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See detailElectric current crowding effects in microstructured superconductors
Adami, Obaïd-Allah ULg

Doctoral thesis (2016)

Many applications of modern electronic devices are based on thin film geometries including sharp turns, holes and exhibiting inhomogeneities. The inevitable detour of current streamlines around such ... [more ▼]

Many applications of modern electronic devices are based on thin film geometries including sharp turns, holes and exhibiting inhomogeneities. The inevitable detour of current streamlines around such obstacles cause an inhomogeneous current density profile giving rise to current crowding. The goal of my research is to highlight the current crowding effects in micro and nanopatterned superconducting films. [less ▲]

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See detailFertility progression in Germany: an analysis using flexible nonparametric cure survival models
Bremhorst, Vincent; Kreyenfeld, Michaela; Lambert, Philippe ULg

in Demographic Research (2016)

OBJECTIVE This paper uses data from the German Socio-Economic Panel (GSOEP) to study the transition to second and third births. In particular, we seek to distinguish the factors that determine the timing ... [more ▼]

OBJECTIVE This paper uses data from the German Socio-Economic Panel (GSOEP) to study the transition to second and third births. In particular, we seek to distinguish the factors that determine the timing of fertility from the factors that influence ultimate parity progression. METHODS We employ cure survival models, a technique commonly used in epidemiological studies and in the statistical literature but only rarely applied to fertility research. RESULTS We find that education has a different impact on the timing and the ultimate probability of having a second and a third birth. Furthermore, we show that the shape of the fertility schedule for the total population differs from that of ‘susceptible women’ (i.e., those who have a second or a third child). CONCLUSION Standard event history models conflate timing and quantum effects. Our approach overcomes this shortcoming. It estimates separate parameters for the hazard rate of having a next child for the ‘susceptible population’ and the ultimate probability of having another child for the entire population at risk. [less ▲]

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See detailHow do we understand Smart City? An Evolutionary Perspective
Crutzen, Nathalie ULg; Kummitha, Rama

Conference (2016, August 25)

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See detailNormative data on teachers’ voice use in real-life situations
Schiller, Isabel ULg; Morsomme, Dominique ULg; Alcoulombre, Anaëlle et al

Conference (2016, August 25)

Background As part of their working routine, teachers use their voice for extended periods of time. To compensate for adverse acoustic conditions and background noise, they are also required to speak at ... [more ▼]

Background As part of their working routine, teachers use their voice for extended periods of time. To compensate for adverse acoustic conditions and background noise, they are also required to speak at high intensities. Since teaching is acknowledged to be vocally demanding, several studies have investigated teachers’ vocal load, that is, the stress inflicted on the larynx during vocalization, which is thought to be influenced by duration, intensity and frequency of phonation. A promising method for analyzing teachers’ phonatory behavior in real-life situations is the use of a portable voice dosimeter that objectively documents vocal parameters. Depending on several factors, those parameters may vary within the teaching profession (Masuda et al., 1993; Morrow and Connor, 2011; Remacle, Morsomme, and Finck, 2014). With the aim of quantifying their vocal parameters and identifying the most at-risk teaching conditions, we have established a large database of French-speaking teachers. Based on this database, this study analyzed vocal loading differences with regard to gender, teaching level, and environment (professional versus extra-professional). Methods Seventy-six French-speaking teachers (15 males and 61 females) were monitored during one workweek using the Ambulatory Phonation Monitor voice dosimeter (KayPENTAX). The subjects included 21 kindergarten, 20 primary and 35 secondary school teachers. All male subjects were in the latter group. The vocal parameters analyzed were phonation time, intensity and fundamental frequency (F0). Results The statistical analysis revealed that, irrespective of gender, phonation time, F0 and intensity level were significantly higher in the professional environment than the extra-professional environment (p<.01). Among female subjects, the F0 of kindergarten teachers was significantly higher than that of primary school teachers, which in turn was higher than that of secondary school teachers (p<.01). The phonation time and intensity were also higher in female kindergarten teachers than other female teachers, but this difference did not reach significance. As expected, regarding gender differences, we found that female secondary school teachers spoke with significantly higher F0 than their male colleagues (p<.001). In the extra-professional setting, they also spoke with a significantly higher intensity (p<.05), but no such effect was found in the professional environment. Conclusion Overall, our subjects showed an increase in vocal loading parameters when they were at work compared to their free time. This confirms the results of earlier studies and demonstrates that teaching is an occupation with remarkably high vocal demands. The analysis of mean frequency showed that lower school levels were associated with higher-pitched voice. It can be assumed that kindergarten teachers adapt to the higher F0 of their young pupils and that their effort to maintain the pupils’ attention results in greater frequency variations. References Masuda, T., Ikeda, Y., Manako, H., & Komiyama, S. (1993). Analysis of vocal abuse: Fluctuations in phonation time and intensity in 4 groups of speakers. Acta Oto-Laryngologica, 113(3), 547–552. Morrow, S. L., & Connor, N. P. (2011). Comparison of voice-use profiles between elementary classroom and music teachers. Journal of Voice, 25(3), 367–372. Remacle, A., Morsomme, D., & Finck, C. (2014). Comparison of vocal loading parameters in kindergarten and elementary school teachers. Journal of Speech, Language, and Hearing Research, 57(2), 406–415. [less ▲]

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See detailDetermining new threshold temperatures for cooling and heating degree day index of different climatic zones of Iran
Roshan, Gh.R.; Ghanghermeh, A.A.; Attia, Shady ULg

in Renewable Energy : An International Journal (2016), 101(2017), 156-167

Iran is a country with a variety of different climates. Determining the threshold temperatures suitable for providing thermal and climatic comfort is necessary and vital to its population well-being. This ... [more ▼]

Iran is a country with a variety of different climates. Determining the threshold temperatures suitable for providing thermal and climatic comfort is necessary and vital to its population well-being. This research presents new threshold temperatures in order to calculate the degree day index required for heating and cooling by taking advantage of the 12 stations that are representative of the diversity of Iran's climate. Using Olgyay diagram, different bioclimatic ranges of 12 weather stations and their frequencies were compiled, processes and analysed. Mean daily data of temperature and relative humidity were used for the period of 1950e2010. Based on the frequencies of temperature readings falling in Olgyay's diagram comfort zone, representive temperature thresholds were selected based on 40 to 60 percentiles or (P20), 25e75% percentile (P50) and the threshold of 10e90% percentile. The findings of this study shows that Mashhad with 29.6% and Anzali with 2.33% of frequencies, have experienced the maximum and minimum days of comfort. After analyzing various percentiles to determine the threshold temperatures, it was observed that there is a little difference among the stations for determining the minimum threshold for the comfort. Differences are more obvious in the maximum thresholds. In total, minimum base temperatures (HDD) belonged to Ardabil stations that were 20.50, 20.90 and 20 deg C for P20, P50 and P80 respectively. The maximum temperature for calculating CDD with values of (P20 ¼ 25 C; P50 ¼ 26.25 C; P80 ¼ 27.50 C) is dedicated to Zabol station. The findings present more reasonable thermal comfort thresholds that can be used by architects, engineers and policy makers to achieve, in turn, more energy efficient homes and high quality indoor and outdoor living environments. [less ▲]

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See detailDobble, analyse d'un jeu de cartes
Rigo, Michel ULg

Conference given outside the academic context (2016)

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See detailNos écosystèmes sont-ils des alliés pour lutter contre le changement climatique?
Heinesch, Bernard ULg

Conference given outside the academic context (2016)

Les écosystèmes terrestres jouent un rôle dans le changement climatique. Ils peuvent notamment échanger des gaz à effet de serre avec l’atmosphère. Ils peuvent par exemple émettre ou séquestrer du CO2, du ... [more ▼]

Les écosystèmes terrestres jouent un rôle dans le changement climatique. Ils peuvent notamment échanger des gaz à effet de serre avec l’atmosphère. Ils peuvent par exemple émettre ou séquestrer du CO2, du CH4 et du N2O en fonction du type d’écosystème, de la façon dont l’homme les exploite et des conditions climatiques. Dans cet exposé, des exemples concrets d’expériences menées sur des forêts, des cultures ou des prairies wallonnes seront utilisés pour illustrer les avancées scientifiques récentes dans le domaine et apporter des réponses à des questions du type: «Est-ce qu’une grande culture permet de stocker du carbone ? Et une prairie ? Que devient le bilan si la prairie est pâturée par du bétail ? Quelles pratiques d’exploitation pourraient améliorer le bilan ?» Des exemples de projets menés au sein des écoles secondaires et associant les élèves et des chercheurs seront aussi présentés. [less ▲]

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See detailSeasonal variation in human brain function
Vandewalle, Gilles ULg

Conference (2016, August 25)

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See detailEtude des rôles du produit d'expression du gène M138L du virus Myxoma dans la pathogénie de la myxomatose
Boutard, Bérengère ULg

Doctoral thesis (2016)

Myxoma virus belongs to the Poxviridae family and induces a severe and often lethal disease called myxomatosis in the European rabbit (Bertagnoli & Marchandeau, 2015). Numerous genes of the virus encode ... [more ▼]

Myxoma virus belongs to the Poxviridae family and induces a severe and often lethal disease called myxomatosis in the European rabbit (Bertagnoli & Marchandeau, 2015). Numerous genes of the virus encode for proteins with immunomodulatory functions (Spiesschaert et al., 2011; Zuniga, 2002). Among them, it has been demonstrated that the virus encodes for an α-2,3-sialyltransferase (Jackson et al., 1999; Markine-Goriaynoff et al., 2004b) that catalyzes the transfer of sialic acid to the N and O-glycans of glycoproteins and glycolipids (Varki & Schauer, 2009). Glycans, and especially sialic acids, are known to play significant roles in interactions and recognition between cells and between cells and viruses (Cohen & Varki, 2010; Raman et al., 2005; Vigerust & Shepherd, 2007). The aim of this thesis was to better understand the roles played by the viral α-2,3-sialyltransferase in the pathogenesis of myxomatosis. Using the Lausanne strain as parental strain, we have constructed strains deficient for the M138L gene encoding the α-2,3-sialyltransferase, and a revertant strain. Although no difference could be detected between the strains in vitro, the M138L knockout strains were highly attenuated in vivo. Especially, we observed more neutrophils at the beginning of infection and then an important mononuclear cells infiltrate in the dermis of the primary sites of infection for rabbits infected with the M138L knockout strains. We then wanted to determine which viral and / or cellular proteins were affected by the viral α-2,3-sialyltransferase, to check if their modification could explain the phenotype that we observed. We showed that the viral M-T7 protein was sialylated by the viral enzyme. M-T7 is a homologue of the interferon-γ receptor (Mossman et al., 1995) which is also able to bind and inhibit several chemokines, to block the chemokine gradient formation and to inhibit the inflammatory cells attraction towards the site of infection (Alcami, 2003; Lalani et al., 1997). However, we could not detect any effect of sialylation on the secretion or the activity of the M-T7 proteins purified from the four strains, either in vitro or in vivo. Altogether , these results show that the viral α-2,3-sialyltransferase is a virulence factor of the virus that could act directly or indirectly on several immunomodulatory viral proteins, and so on the immune cells attraction and adaptive immunity development. [less ▲]

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See detailEtude des sémiochimiques volatils impliqués dans le mutualisme fourmis-pucerons
Fischer, Christophe ULg

Doctoral thesis (2016)

For decades, the mutualistic relationship that ant and aphids may present has fascinated entomologists, as evidenced by the abundant literature on the subject. The principles of this interaction are ... [more ▼]

For decades, the mutualistic relationship that ant and aphids may present has fascinated entomologists, as evidenced by the abundant literature on the subject. The principles of this interaction are simple: as long as their colony remains, aphids provide ants with a stable and abundant source of sugars, honeydew. In exchange, ants tend aphid colonies and provide them cleaning and protection against various natural enemies. Nevertheless, some aspects of this relationship remain misunderstood. This is for example the case of the factors influencing the search and the discovery of a potential partner, first step to any potential mutualistic interaction. The role held by volatile chemical cues, called semiochemicals, in this relationship is also misunderstood. The objective of this thesis is to improve understanding of the role played by volatile semiochemicals in this mutualistic relationship, especially during the partner search stage, both from the perspective of the ant and of the aphid. The black garden ant, Lasius niger L., and the black bean aphid, Aphis fabae Scop., constitute our biological model. The impact of volatile compounds on the search behavior of the ant has first been investigated. These compounds are from multiple origins, either directly emitted by the aphid or induced by its presence. First, the ability of ants to perceive E-β-farnesene, the main component of many aphid alarm pheromone, and to use it to locate aphid colonies has been highlighted. This compound has indeed shown attractiveness to ants, even at low doses corresponding to the emissions of an unstressed aphid colony. Then, the roles played by honeydew volatile compounds in ant attraction have been demonstrated. These compounds also allow ants to remotely discriminate different aphid species and to direct their searches accordingly. These semiochemicals are produced by honeydew microflora, and a particularly attractive bacterial strain, Staphylococcus xylosus, has been isolated from A. fabae honeydew. Finally, the active role of winged aphids, which are aphid’s dispersal form, in the search for a mutualistic partner was also studied. Aphids do not appear to be preferentially attracted toward a host plant frequented by ants or close an ant nest. Nevertheless, once a potential host plant reached, they remain longer on it in case of ant presence. This thesis highlights the importance of volatile semiochemicals and honeydew microflora in ant-aphid mutualistic relationships, thus completing by a new aspect an already well documented biological model. [less ▲]

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See detailAgeism in Belgium and Burundi: A comparative analysis
Marquet, Manon ULg; Missotten, Pierre ULg; Schroyen, Sarah ULg et al

in Clinical Interventions in Aging (2016), 11

Background: Recent cross-cultural comparisons between Asian and Western cultures have shown that ageism arises more from the lack of availability of social and economic resources for older adults than ... [more ▼]

Background: Recent cross-cultural comparisons between Asian and Western cultures have shown that ageism arises more from the lack of availability of social and economic resources for older adults than from the culture itself. We tested this assumption by conducting a survey among people living in a least-developed country compared with a developed country. Methods: Twenty-seven Belgians living in Belgium, 29 Burundians living in Belgium and 32 Burundians living in Burundi were included in this study. Their attitudes toward older adults were assessed using several self-reported measures. Results: Statistical analyses confirmed that older people are more negatively perceived by Burundians living in Burundi than by Burundians and Belgians living in Belgium, whose attitudes did not differ from each other. Conclusion: Consistent with our hypothesis, our results suggest that the level of development of a country and more particularly the lack of government spending on older people (pension and healthcare systems) may contribute to their younger counterparts perceiving them more negatively. [less ▲]

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See detailMESURES INCITATIVES A LA PRODUCTION COTONNIERE ET PERSPECTIVES DE LA PRIVATISATION DES FILIALES CMDT AU MALI
Koné, Bouréma ULg

Doctoral thesis (2016)

Cotton is the first export crop in Mali with 84,370 billion Fcfa in 2010 (INSTAT, 2010), but the production of this crop has huge problems due to external factors (prices of inputs and seed cotton) and ... [more ▼]

Cotton is the first export crop in Mali with 84,370 billion Fcfa in 2010 (INSTAT, 2010), but the production of this crop has huge problems due to external factors (prices of inputs and seed cotton) and internal (within payment to producers, internal debts of cooperatives). To boost cotton production during the years 2010/11 and 2011/12, the government had maintained the level of fertilizer subsidy at 50% of normal price on the market. In addition to this level of subsidy, the incentive price of 255Fcfa / kg was fixed to the producer and the National Union of Cotton Producers Cooperative Societies (NU-CPCS) facilitated the clearance of the internal debts of cooperatives. Despite the fall in world prices after 2011/12, the price of cotton seed remains little changed. The price stayed at 255 CFA francs / kg in 2012/13 and got back to 250 CFA francs / kg in 2013/14. The objective of this work is to analyze the effects of incentives factors cotton production with a view to the privatization of CMDT subsidiaries Surveys were conducted with a sample of 240 farms selected from the four zones of the CMDT zones based on two villages subsidiary during the years of 2008/09, 2010/11 and 2011/12. The results showed a positive trend in production (mainly due to an increase in the area) and in the income of cotton producers with a higher reimbursement rate of input credits under cultivation. The analysis of the Domestic Resource Cost (DRC) the Nominal protection coefficients (NPC) and the Effective (CPE) showed an improvement in thèse variables in 2011/12 with the incentive policy. An analysis of the determinants of the supply of cotton showed that only two variables were significant: the price cottonseed and payment period. The incentive factors are influenced by fiber market in 2011/12 which took a downward trend from the campaign. This incentive policy being favored by the market of fiber which is very unstable, it would be necessary to create conditions in which the producer can benefit from the price obtained on the quality of fiber to maintain the incentive policy for producers. For the privatization of Cotton Company, an upgrade of this company is necessary with the support of the Malian state. But this upgrade should not affect too much the selling price of sale of cotton that can bring new companies in a situation of too long term recovery of capital invested (long period of investment recovery). The privatization scheme as presented makes major companies more competitive. In order to reduce the operating costs a form of collaborative relationships among delivery companies would be required. Keywords: fertilizer subsidy, incentive price, cotton sector in Mali, privatization subsidiary, competitiveness. [less ▲]

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See detailOverhanging Constraints in Addivitive Manufacturing Using Two Different Tools
Bauduin, Simon ULg; Collet, Maxime ULg; Duysinx, Pierre ULg

Poster (2016, August 23)

Topology optimization is widely used as a design tool for advanced application in mechanical, aerospace and automotive industries. This technique offers an optimal distribution of a predetermined amount ... [more ▼]

Topology optimization is widely used as a design tool for advanced application in mechanical, aerospace and automotive industries. This technique offers an optimal distribution of a predetermined amount of material in a given design space. In the last years, a lot of efforts has been invested into the development of high performance methods such as homogenization, SIMP or BESO. However as the state of the art in manufacturing experiences evolution, a coupling between topology optimization and additive manufacturing is needed. Additive manufacturing has numerous advantages that fits the characteristics of topology optimized designs. It can manufacture highly complex design without high cost increase and furthermore continuous density material of the SIMP method could be manufactured by lattice structures. With all the opportunities given by the additive manufacturing the urge to bind the last one to topology optimization is heavily required. Specific constraints related to manufacturing issues have to be taken into account such as the need of supports structures to ensure a good heat evacuation during the manufacturing process, as well as to hold up overhanging section. Some researches have been done to try to include this constraint in the optimization problem such as Leary and al or Andrew T. Gaynor. However this work focuses on 2 different methods (projection scheme and mechanical approach) to tackle the overhanging problem and compare them . [less ▲]

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See detailGraphene-multiferroic interfaces for spintronics applications
Zanolli, Zeila ULg

in Scientific Reports (2016)

Graphene and magnetoelectric multiferroics are promising materials for spintronic devices with high performance and low energy consumption. A very long spin di usion length and high carrier mobility make ... [more ▼]

Graphene and magnetoelectric multiferroics are promising materials for spintronic devices with high performance and low energy consumption. A very long spin di usion length and high carrier mobility make graphene attractive for spintronics. The coupling between ferroelectricity and magnetism, which characterises magnetoelectrics, opens the way towards unique device architectures. In this work, we combine the features of both materials by investigating the interface between graphene and BaMnO3, a magnetoelectric multiferroic. We show that electron charge is transferred across the interface and magnetization is induced in the graphene sheet due to the strong interaction between C and Mn. Depending on the relative orientation of graphene and BaMnO3, a quasi-half-metal or a magnetic semiconductor can be obtained. A remarkably large proximity induced spin splitting of the Dirac cones (~300 meV) is achieved. We also show how doping with acceptors can make the high-mobility region of the electronic bands experimentally accessible. This suggests a series of possible applications in spintronics (e.g. spin filters, spin injectors) for hybrid organic-multiferroic materials and reveals hybrid organic-multiferroics as a new class of materials that may exhibit exotic phenomena such as the quantum anomalous Hall effect and a Rashba spin-orbit induced topological gap. [less ▲]

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See detailSO(10) models with flavour symmetries: Classification and examples
Ivanov, Igor ULg; Lavoura, Luis

in Journal of Physics : G Nuclear & Particle Physics (2016), 43(10), 105005

Renormalizable SO(10) grand unified theory (GUT) models equipped with flavour symmetries are a popular framework for addressing the flavour puzzle. Usually, the flavour symmetry group has been an ad hoc ... [more ▼]

Renormalizable SO(10) grand unified theory (GUT) models equipped with flavour symmetries are a popular framework for addressing the flavour puzzle. Usually, the flavour symmetry group has been an ad hoc choice, and no general arguments limiting this choice were known. In this paper, we establish the full list of flavour symmetry groups which may be enforced, without producing any further accidental symmetry, on the Yukawa-coupling matrices of an SO(10) GUT with arbitrary numbers of scalar multiplets in the ${\bf{10}}$, $\bar{{\bf{126}}}$, and ${\bf{120}}$ representations of SO(10). For each of the possible discrete non-Abelian symmetry groups, we present examples of minimal models which do not run into obvious contradiction with the phenomenological fermion masses and mixings. [less ▲]

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See detailLa santé psycho-sociale des adolescents à l’épreuve de l’immigration : le cas des jeunes d’origine marocaine et turque en Belgique.
Gavray, Claire ULg

Conference (2016, August 23)

Cette communication s’appuie sur les analyses effectuées au départ des données belges de l’enquête ‘International Study on Self-reported Delinquency’. Nous investiguons la question du mal-être ... [more ▼]

Cette communication s’appuie sur les analyses effectuées au départ des données belges de l’enquête ‘International Study on Self-reported Delinquency’. Nous investiguons la question du mal-être psychologique desadolescents autochtones et allochtones (via échelle réduite de dépression des adolescents de Moos) encomparaison et en lien avec leur contexte social, affectif et relationnel. Nous affinons l’analyse en ce qui concerne les jeunes d’origine turque et marocaine vivant en Belgique, sachant que si les deux sous-groupes nationaux partagent de nombreuses expériences dans leurs relations aux différentes sphères sociales, leur groupe d’origine se caractérise aussi par des stratégies économiques et d’insertion qui peuvent différer. Nous discutons le résultat selon lequel, malgré un contexte social et historique plus favorable, les jeunes d’origine belge manifestent une tendance dépressive plus prononcée que les autres et la conclusion selon laquelle ce n’est pas automatiquement et exactement les mêmes facteurs socio-relationnels qui expliquent le niveau de dépression dans chacun des groupes étudiés. [less ▲]

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See detailThe influence of background noise on vocal loading parameters in music theory teachers
Schiller, Isabel ULg; Morsomme, Dominique ULg; Sfez, Lou et al

Poster (2016, August 23)

Background: Music theory teachers, who teach rhythm, singing and other music-related skills and topics, depend greatly on a well-functioning voice. Unlike other schoolteachers, who primarily use their ... [more ▼]

Background: Music theory teachers, who teach rhythm, singing and other music-related skills and topics, depend greatly on a well-functioning voice. Unlike other schoolteachers, who primarily use their voice as a pedagogic tool, music theory teachers also use it as an instrument. Furthermore, they often engage in vocally demanding free-time activities requiring a singing voice. To date, few studies have specifically looked at the voice use of music theory teachers. This study aims (1) to measure the background noise level and the amount of vocal loading affecting this specific population, and (2) to describe the influence of background noise on vocal loading parameters. Methods: Thirteen French-speaking music theory teachers (9 females and 4 males) working in a music school were monitored for one workweek, using the VoxLog voice dosimeter (Sonvox). To investigate the professional and extra-professional environments, all subjects wore the dosimeter from early morning until the end of the day. The parameters analysed were background noise level, duration of phonation, sound pressure level (SPL) and fundamental frequency (F0) of voice. Results: Overall, the mean background noise level was 75.2 dB (SD=5.4). We measured higher background noise level at work (mean=78.2 dB, SD=5.8) than in the extra-professional environment (mean=72.2 dB, SD=5.2). As expected, a rise in background noise was accompanied by a significant rise in voice SPL in both males and females (r=.61, p<.001). A significant correlation between background noise and F0 was found in females (r=.41, p=.002), but not in males (r=.39, p=.055). Furthermore, our data exhibit a significant correlation between background noise and duration of phonation (r=.05, p<.001). Conclusion: Our data suggest, that in class, music theory teachers must cope with background noise levels that dramatically exceed the limit of 35 dB recommended by the WHO (Inserm, 2006). High background noise levels lead to an increase in voice SPL, a phenomenon known as the Lombard effect (Inserm, 2006). In female subjects, we also observed a rise in F0 further to high background noise. Like Ternström, Södersten, and Bohman’s (2002) study, our data indicate that high background noise levels increase the duration of phonation. In a noisy environment, subjects seem to prolong the voiced segments of speech to make themselves understood. In other words, high background noise levels result in higher vocal loading. In the long run, this may increase the risk of voice disorders such as hyperfunctional dysphonia or vocal fold pathologies consecutive to repeated microtrauma in music theory teachers. [less ▲]

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