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See detailWhy do temporal generalization gradients change when people make decisions as quickly as possible?
Klapproth, Florian UL; Wearden, John H.

in Quarterly Journal of Experimental Psychology (2011), 64(8), 1646-1664

Three experiments investigated temporal generalization performance under conditions in which participants were instructed to make their decisions as quickly as possible (speed), or were allowed to take ... [more ▼]

Three experiments investigated temporal generalization performance under conditions in which participants were instructed to make their decisions as quickly as possible (speed), or were allowed to take their time (accuracy). A previous study (Klapproth & Müller, 2008) had shown that under speeded conditions people were more likely to confuse durations shorter than the standard with the standard than in the accuracy conditions, and a possible explanation of this result is that longer stimulus durations are "truncated" (i.e., people make a judgement about them before they have terminated, thereby shortening their effective duration) and that these truncated durations affect the standard used for the task. Experiment 1 investigated performance under speed and accuracy conditions when comparison durations were close to the standard or further away. No performance difference was found as a function of stimulus spacing, even though responses occurred on average before the longest durations had terminated, but this lack of effect was attributed to "task difficulty" effects changing decision thresholds. In Experiment 2, the standard duration was either the longest or the shortest duration in the comparison set, and differences between speed and accuracy groups occurred only when the comparisons were longer than the standard, supporting the "truncation" hypothesis. A third experiment showed that differences between speed and accuracy groups only occurred if some memory of the standard that was valid for more than one trial was used. In general, the results suggest that the generalization gradient shifts in speeded conditions occur because of truncation of longer comparison durations, which influences the effective standard used for the task. [less ▲]

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See detailWhy do we make Cu(In,Ga)Se2 solar cells non-stoichiometric?
Siebentritt, Susanne UL; Gütay, Levent UL; Regesch, David UL et al

in Solar Energy Materials & Solar Cells (2013)

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See detailWhy do you play World of Warcraft? An in-depth exploration of self-reported motivations to play online and in-game behaviours in the virtual world of Azeroth
Billieux, Joël UL; Van Der Linden, M.; Achab, S. et al

in Computers in Human Behavior (2013), 29(1), 103-109

Massively multiplayer online role-playing games (MMORPGs) are video games in which players create an avatar that evolves and interacts with other avatars in a persistent virtual world. Motivations to play ... [more ▼]

Massively multiplayer online role-playing games (MMORPGs) are video games in which players create an avatar that evolves and interacts with other avatars in a persistent virtual world. Motivations to play MMORPGs are heterogeneous (e.g. achievement, socialisation, immersion in virtual worlds). This study investigates in detail the relationships between self-reported motives and actual in-game behaviours. We recruited a sample of 690 World of Warcraft players (the most popular MMORPG) who agreed to have their avatar monitored for 8 months. Participants completed an initial online survey about their motives to play. Their actual in-game behaviours were measured through the game's official database (the Armory website). Results showed specific associations between motives and in-game behaviours. Moreover, longitudinal analyses revealed that teamwork- and competition-oriented motives are the most accurate predictors of fast progression in the game. In addition, although specific associations exist between problematic use and certain motives (e.g. advancement, escapism), longitudinal analyses showed that high involvement in the game is not necessarily associated with a negative impact upon daily living. © 2012 Elsevier Ltd. All rights reserved. [less ▲]

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See detailWhy does multi-situated ethnography develop new competences for sociological research on the poorest and most excluded populations' health as well as for evidence-based health promotion interventions?
Lurbe-Puerto, Katia UL; Baumann, Michèle UL

in European Society for Health and Medical Sociology (2010)

When extremely poor and excluded populations are concerned, Multi-Situated Ethnography (MSE) represents a valuable research design for health needs and resources diagnosis* and for the improvement of ... [more ▼]

When extremely poor and excluded populations are concerned, Multi-Situated Ethnography (MSE) represents a valuable research design for health needs and resources diagnosis* and for the improvement of health promotion programmes. By focusing on the results of our 2-years community-based participatory study on prevention amongst Roma populations living in France**, we will assess the potentials of ethnography-based research for both scientific production and health promotion interventions. Methods/actions. A MSE has been carried in three distinct scenarios, selected because of the different socio-cultural integration levels and life conditions of the Roma families. There are: 1) the Forest of Mery-sur-Oise, a shanty town where around twenty Roma families live, 2) the collective emergency housing in the old headquarters in Saint-Maur-des-Fossé, and 3) S.A.N. de Sénart, a conglomeration of towns which an integration plan of Roma people was launched in. This fieldwork has produced scientific data on the healthcare provision and the social accompaniment realised by professionals of the health, social and administrative sectors as well as on Roma’s health promotion practices. A reflexive evaluation design was undertaken through the conduction of an expert panel involving 3 sociologists and 3 social workers, meeting each month. Results. The MSE allowed building up comparative relations between health practices and socio-economic and geo-political factors amongst “hermetical populations” when they asked to share information on their life with outsiders. Simultaneously, the data analysis allowed considering: universal similarities, cultural differences and individual singularities. The increased of the methodological procedures as it helped avoid falling into stigma reification of groups already highly racially discriminated. Its participatory dimension helped document and share learning across contexts, providing a renewed source of dynamism amongst professionals dealing with sensitive fields and very difficult to access. Because of the sensitivity brought by its in-depth comprehensive-based approach, it moved closer professionals to their Roma beneficiaries, even leading to cases of conflict resolution between both actors. Conclusion. The acquisition of the required skills to carry out a social and health intervention based on a community-based participatory diagnostic of needs and resources and, on an evaluative follow-up of the actions undertaken within the intervention scenario is a major asset for the elaboration and management of individual or community-dimensioned professional projects. MSE needs to be revisited and revalued as it comprises useful a set of competences to give informed guidance by supplying decision-makers and professionals, with sound and comprehensive analysis. [less ▲]

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See detailWhy is it so hard? And for whom? Obstacles in the intra-EU mobility: Mobility fields in comparison
Kmiotek, Emilia Alicja UL; Ardic, Tuba; Dabasi-Halász, Zsuzsanna et al

Scientific Conference (2018, March 08)

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See detailWHY IS THE MARKET SKEWNESS-RETURN RELATIONSHIP NEGATIVE?
Lehnert, Thorsten UL

E-print/Working paper (2018)

The observed negative relationship between market skewness and excess return or the negative price of market skewness risk in the cross-section of stock returns is somewhat counterintuitive when we ... [more ▼]

The observed negative relationship between market skewness and excess return or the negative price of market skewness risk in the cross-section of stock returns is somewhat counterintuitive when we consider the usual interpretation of e.g. option-implied skewness as an indicator of jump risk or downside risk. One possible explanation for this inconsistency is that there are factors affecting option-implied market skewness other than jump risk in the stock market. In this paper, I find that price pressure associated with “crowded trades” of mutual funds is an important endogenous factor. Given that retail investors are prone to herding, the directional trading of mutual funds is correlated, and their collective actions can generate short-term price pressure on aggregate stock prices. Short sellers systematically exploit these patterns not only in the equity lending market, but also in the options market. In line with this economic channel, I find that firstly, the significant negative relationship between market skewness and returns becomes insignificant, once I control for price pressure. Secondly, the negative relationship is only present for the “bad” downside component of risk-neutral skewness, associated with out-of-the-money put options. For the “good” upside component of risk-neutral skewness, associated with out-of-the-money call options, the relationship is always positive. Thirdly, price pressure affects the skewness-return relationship, which can be clearly distinguished from the impact of flows on the volatility-return relationship in terms of the leverage effect. [less ▲]

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See detailWhy medication or tobacco consumption enhance the life satisfaction of cardiovascular patients?
Bucki, Barbara UL; Tchicaya, Anastase; Baumann, Michèle UL

in European Health Psychologist (The) (2015), special

While life satisfaction (LS) promotes the health of cardiovascular patients, LS may be affected by a range of primary and secondary determinants. We analysed LS and its relationships with cardiovascular ... [more ▼]

While life satisfaction (LS) promotes the health of cardiovascular patients, LS may be affected by a range of primary and secondary determinants. We analysed LS and its relationships with cardiovascular risk factors and unhealthy behaviours. Methods. In 2013, 3,632 survivors who underwent coronary angiography in 2008-2009 at the Luxembourgish National Institute of Cardiac Surgery and Cardiological Intervention (INCCI), living at home were asked to estimate, five years after, their LS [1-10] and other health-related variables. Data were analysed via multiple regression models including interaction effects. Findings. LS of the 1,289 participants (age: 69.2±11.1) was 7.3/10. Most were men, employees or manual workers, had secondary education and a 36,000€ or more/year income. The interactions between hypercholesterolemia and hypertension (regression coefficient= 0.628) and with smoking (rc= 0.941) were positively related with LS, but physical inactivity was negatively associated (rc= -0.630). Discussion. Taking medications or maintaining tobacco consumption produces better LS than being ambivalent towards physical activity. Further research is needed to evaluate the efficacy of health interventions eliciting and promoting the behaviour change wheel based on capabilities, opportunities, and motivations. [less ▲]

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See detailWhy organically functionalized nanoparticles increase the electrical conductivity of nematic liquid crystal dispersions
Urbanski, Martin; Lagerwall, Jan UL

in Journal of Materials Chemistry C (2017), 5(34), 8802-8809

Doping liquid crystals with gold nanoparticles increases the conductivity by up to three orders of magnitude, an increase even stronger than expected for equimolar amounts of organic electrolytes. Despite ... [more ▼]

Doping liquid crystals with gold nanoparticles increases the conductivity by up to three orders of magnitude, an increase even stronger than expected for equimolar amounts of organic electrolytes. Despite recent high activity in the field of liquid crystalline nanocomposites, the origin of this increase has rarely been addressed and is not well understood. In this dielectric spectroscopy study we discuss the origin of the increased conductivity and identify its source. We demonstrate that the hydrodynamic radius of the mobile charge carrier species in nanoparticle dispersions is significantly smaller than the 3–5 nm gold core, which rules out the particles themselves to be the source of conductivity. Likewise, also the ligand molecules from the organic capping layer do not themselves add to the conductivity of the dispersions, but affect the electrical properties by acting as a trap for ionic impurities. We suggest that the partial release of these impurities upon interactions of the ligand shell with the uniaxial nematic host phase is the most likely source for the increased conductivity. Our study opens a new perspective on synthesis strategies for functionalized nanoparticles and will help to overcome the current issues preventing high-performing liquid crystal nanodispersions. [less ▲]

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See detailWhy Should Judges Be independent? Reflections on Coke, Montesquieu and the French Tradition of Judicial Dependence
Heuschling, Luc UL

in Baranger, Denis; Ziegler, Katja; Bradley, Anthony W. (Eds.) Constitutionalism and the Role of Parliaments (2007)

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See detailWhy so few, and why so late? Green parties and the question of governmental participation
Dumont, Patrick UL; Bäck, Hanna

in EUROPEAN JOURNAL OF POLITICAL RESEARCH (2006), 45

Green parties have been represented in the parliaments of European Union countries since 1981, but it was not until recently that a few have entered national governments. Using a data set comprised of 51 ... [more ▼]

Green parties have been represented in the parliaments of European Union countries since 1981, but it was not until recently that a few have entered national governments. Using a data set comprised of 51 government formation opportunities (where the Greens were represented in parliament), the authors of this article show that the parties involved in these bargaining situations are more office-oriented than earlier studies had found. As Green parties are seen to be less office-seeking than other parties, this general tendency for office-seeking behaviour in government formation may partly account for the scarcity of Greens in government. Furthermore, a number of hypotheses derived from theories that account for the specific nature of Green parties in terms of their office-, policy- and vote-seeking orientations are tested. It is found that Greens participate in government when they have lost votes in at least one election, when the main party of the left identifies them as a clear electoral threat and when the policy distance between the Greens and either the formateur party or the main left party is small (the latter condition must be accompanied by a substantial proportion of seats for the Green party in parliament). As most of these simultaneous conditions only materialized recently, and in a few countries, it is argued that this analysis, which is the first comparative and multivariate test focused on this question, explains the scarcity and the delay of Green governmental participation. [less ▲]

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See detailWhy social studies of childhood? An introduction to the handbook
Honig, Michael-Sebastian UL; Qvortrup, Jens; Corsaro, William A.

in Qvortrup, Jens; Corsaro, William A.; Honig, Michael-Sebastian (Eds.) The Palgrave Handbook of Childhood Studies (2009)

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See detailWhy ‘what works’ still won’t work. From evidence-based education to value-based education.
Biesta, Gert UL

in Studies in Philosophy & Education (2010), 29(5), 491-503

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See detail„Why“ is the answer not the question: The role of perceived responsibility and control for emotional adaptation in cancer patient
Hoffmann, Martine UL; Lessing, J.; Ferring, Dieter UL

in Annual Conference of the Canadian Association of Psychosocial Oncology. Vancouver, Canada (2009)

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See detailWi-Fi butterfly effect in indoor localization: The impact of imprecise ground truth and small-scale fading
Popleteev, Andrei UL

in 14th IEEE Workshop on Positioning, Navigation and Communications (WPNC-2017) (2017, October)

The increasing accuracy of indoor positioning systems makes their evaluation an increasingly challenging task. A number of factors are already known to affect performance of fingerprint-based systems ... [more ▼]

The increasing accuracy of indoor positioning systems makes their evaluation an increasingly challenging task. A number of factors are already known to affect performance of fingerprint-based systems: hardware diversity, device orientation, environment dynamics. This paper presents a new butterfly-like effect in localization experiments. The effect is caused by minor ground truth (GT) errors --- that is, small deviations between calibration and test positions. While such deviations are widely considered as purely additive and thus negligible, we demonstrate that even centimeter-scale GT errors are amplified by small-scale radio fading and lead to severe multi-meter Wi-Fi positioning errors. The results show that fingerprint-based localization accuracy quickly deteriorates as GT errors increase towards 0.4 wavelength (5 cm for 2.4 GHz). Beyond that threshold, system's accuracy saturates to about one-third of its original level achievable with precise GT. This effect challenges the impact of the already known accuracy-limiting factors (such as cross-user tests, receiver diversity, device orientation and temporal variations), as they can be partially explained by minor GT errors. Moreover, for smartphone-in-a-hand experiments, this effect directly associates the evaluation outcomes with experimenters' diligence. [less ▲]

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See detailWideband Identification of Power Network Parameters Using Pseudo-Random Binary Sequences on Power Inverters
Neshvad, Surena UL; Chatzinotas, Symeon UL; Sachau, Jürgen UL

in IEEE Transactions on Smart Grid (2015)

Due to the push for renewable energy in the last decades, European countries have witnessed an exponential growth of Distributed Generation (DG) on the Medium Voltage (MV) network. An increasingly large ... [more ▼]

Due to the push for renewable energy in the last decades, European countries have witnessed an exponential growth of Distributed Generation (DG) on the Medium Voltage (MV) network. An increasingly large portion of the electricity demand is fed in through the distribution grid, whose good health and operational status will be important for guaranteeing grid stability. In Luxembourg, the distribution network is sparsely monitored and controlled, thus instabilities arising due to line overvoltage or DG malfunctioning are not rapidly detected and resolved. This research discusses a novel and low infrastructure methodology for online monitoring of the distribution grid. Such a tool will be increasingly necessary in order to guarantee the stability, reliability and security of the power network, as a larger and larger portion of the energy demand will be satisfied by DG in future years. In this research, advanced system identification techniques utilized in communications, such as Pseudo-Random Binary Sequences, Successive Interference Cancellation are applied to estimate the transfer function of power network propagation paths. The developed method proposes an online monitoring tool that computes grid parameters in real time during operation, without extensive infrastructure addition, by utilizing the PWM based inverters on the grid for active system identification. [less ▲]

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See detailWider das Lernen. Die Wiedergewinnung einer Sprache für Erziehung im Zeitalter des Lernens.
Biesta, Gert UL

in Vierteljahresschrift für wissenschaftliche Pädagogik (2008), 84(2), 179-194

Detailed reference viewed: 179 (0 UL)