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See detailUnderstanding Molecular Crystals with Dispersion-Inclusive Density Functional Theory: Pairwise Corrections and Beyond
Kronik, Leeor; Tkatchenko, Alexandre UL

in ACCOUNTS OF CHEMICAL RESEARCH (2014), 47(11, SI), 3208-3216

Molecular crystals are ubiquitous in many areas of science and engineering, including biology and medicine. Until recently, our ability to understand and predict their structure and properties using ... [more ▼]

Molecular crystals are ubiquitous in many areas of science and engineering, including biology and medicine. Until recently, our ability to understand and predict their structure and properties using density functional theory was severely limited by the lack of approximate exchangecorrelation functionals able to achieve sufficient accuracy. Here we show that there are many cases where the simple, minimally empirical pairwise correction scheme of Tkatchenko and Scheffler provides a useful prediction of the structure and properties of molecular crystals. After a brief introduction of the approach, we demonstrate its strength through some examples taken from our recent work. First, we show the accuracy of the approach using benchmark data sets of molecular complexes. Then we show its efficacy for structural determination using the hemozoin crystal, a challenging system possessing a wide range of strong and weak binding scenarios. Next, we show that it is equally useful for response properties by considering the elastic constants exhibited by the supramolecular diphenylalanine peptide solid and the infrared signature of water libration movements in brushite. Throughout, we emphasize lessons learned not only for the methodology but also for the chemistry and physics of the crystals in question. We further show that in many other scenarios where the simple pairwise correction scheme is not sufficiently accurate, one can go beyond it by employing a computationally inexpensive many-body dispersive approach that results in useful, quantitative accuracy, even in the presence of significant screening and/or multibody contributions to the dispersive energy. We explain the principles of the many-body approach and demonstrate its accuracy for benchmark data sets of small and large molecular complexes and molecular solids. [less ▲]

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See detailUnderstanding Moral Decision-Making in Video Games: A Focus Group Study
Holl, Elisabeth UL; Bernard, Steve UL; Melzer, André UL

Scientific Conference (2020, May)

Moral dilemmas have become increasingly popular in video games, although it is still widely unknown why players might find them pleasurable, how they process dilemmas, and which factors affect the ... [more ▼]

Moral dilemmas have become increasingly popular in video games, although it is still widely unknown why players might find them pleasurable, how they process dilemmas, and which factors affect the processing. Therefore, three different focus groups sessions with expert gamers (N = 16) were conducted. Gamers’ expressions of their experience with meaningful and morally relevant game situations were grouped for relevant topics. Topics are supported by direct quotations from participants of discussion groups, referring to up-to-date video game titles and presented together with respective theoretical assumptions. Results show that besides the game-defining theme of interactivity, statements can be grouped broadly into factors that describe why players engage or disengage in the first place (motivation) and factors that shape the moral interaction itself (influencing factors). In summary, our findings support the notion that moral-decision making in video games is a dynamic interplay between several game and user-dependent variables. Findings provide insights into players’ processing of moral dilemmas in video games, which also offers promising suggestions for future research using experimental setups. [less ▲]

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See detailUnderstanding non-covalent interactions in larger molecular complexes from first principles
Al-Hamdani, Yasmine; Tkatchenko, Alexandre UL

in Journal of Chemical Physics (2019), 150

Non-covalent interactions pervade all matter and play a fundamental role in layered materials, biological systems, and large molecular complexes. Despite this, our accumulated understanding of non ... [more ▼]

Non-covalent interactions pervade all matter and play a fundamental role in layered materials, biological systems, and large molecular complexes. Despite this, our accumulated understanding of non-covalent interactions to date has been mainly developed in the tens-of-atoms molecular regime. This falls considerably short of the scales at which we would like to understand energy trends, structural properties, and temperature dependencies in materials where non-covalent interactions have an appreciable role. However, as more reference information is obtained beyond moderately sized molecular systems, our understanding is improving and we stand to gain pertinent insights by tackling more complex systems, such as supramolecular complexes, molecular crystals, and other soft materials. In addition, accurate reference information is needed to provide the drive for extending the predictive power of more efficient workhorse methods, such as density functional approximations that also approximate van der Waals dispersion interactions. In this perspective, we discuss the first-principles approaches that have been used to obtain reference interaction energies for beyond modestly sized molecular complexes. The methods include quantum Monte Carlo, symmetry-adapted perturbation theory, non-canonical coupled cluster theory, and approaches based on the random-phase approximation. By considering the approximations that underpin each method, the most accurate theoretical references for supramolecular complexes and molecular crystals to date are ascertained. With these, we also assess a handful of widely used exchange-correlation functionals in density functional theory. The discussion culminates in a framework for putting into perspective the accuracy of high-level wavefunction-based methods and identifying future challenges. [less ▲]

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See detailUnderstanding political processes: A new arena for cultural psychology
Valsiner, Jaan UL

in Magioglou, Thalia (Ed.) Culture and political psychology : A societal perspective (2014)

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See detailUnderstanding primary-school students' beliefs regarding the adoption of pro-environmental behaviors
De Leeuw, Astrid UL; Valois, Pierre

in International Journal of Education, Economics, and Management Engeneering (2014), 8(5), 1391-1395

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See detailUnderstanding primary-school, high-school and university students sustainable behaviours: An approach based on the theory of planned behaviour
De Leeuw, Astrid UL

Doctoral thesis (2015)

Developing a more thorough understanding of what motivates young people to adopt sustainable behaviours is an important area of concern that has practical implications for creating sound educational ... [more ▼]

Developing a more thorough understanding of what motivates young people to adopt sustainable behaviours is an important area of concern that has practical implications for creating sound educational interventions and ensuring a sustainable future. The overall purpose of this thesis was to assess and understand primary- and high-school students’ environmentally sustainable behaviours in order to inform educational interventions. Moreover, it aimed at analysing one particular socially sustainable behavioural intention among university students, notably their intention to buy fair trade products. The theory of planned behaviour (TPB) was used as the basic theoretical framework to examine these behaviours. We first conducted a pilot study for each behaviour, with the aim to identify salient beliefs of the target populations with regard to the behaviour investigated. Open-ended questionnaires were administered to a sample of 116 primary-school students, 92 high-school students, and 17 voluntary participants at the university level. A content analysis of the participants’ responses allowed the determination of the most salient beliefs, which were used as the basis for the quantitative measures of beliefs in the main studies. The first and second main studies investigated the beliefs of 812 primary-school students and 602 high-school students regarding the adoption of pro-environmental behaviours using a longitudinal approach. The gist of our results seems to be that for both age groups, educational interventions should target control beliefs especially. For instance, students insist on tools that would facilitate pro-environmental behaviours (e.g., having duplex printers or recycling bins at school and at home). However, behavioural and normative beliefs should not be neglected. The last study examined mainly differences in male and female university students’ intentions to consume fair trade products. The results indicate that for women, more emphasis should be placed on perceived behavioural control (e.g., factors that facilitate the ii purchase of fair trade products), while for men, more emphasis should be placed on attitudes towards buying fair trade products (i.e., the advantages of adopting this behaviour). Our results confirm the usefulness of the TPB as a framework for understanding young people’s sustainable intentions and behaviours, with perceived control and attitudes having considerable impacts on sustainable intentions and perceived social pressure having a rather low weight. In addition, perceived control and intentions contributed significantly to the explained variance in primary- and high-school students’ eco-friendly behaviours. This thesis makes a number of important contributions to the literature. From a practical point of view, primary- and high-school students are important populations because sustainability-related habits might be established early in life. Moreover, in their roles as potentially important future decision makers in our society (e.g., future company leaders, politicians, global citizens), university students should be sensitized to the unequal power relationships often involved in conventional trading. Offering fair trade products and encouraging their consumption should be considered a small, but important, step in universities’ duty to create awareness. Despite the positive input for interventions inspired by this thesis, some limitations have to be considered, for instance, our reliance on self-report questionnaires and the possibility that participants may have overestimated the extent to which they perform environmentally and socially desirable behaviours related to sustainability. Last, further research is needed to test the effectiveness of interventions based on the present results. [less ▲]

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See detailUnderstanding procrastination: A motivational approach
Grund, Axel UL; Fries, Stefan

in PERSONALITY AND INDIVIDUAL DIFFERENCES (2018), 121

Procrastination is often seen as a self-regulatory failure. We want to offer a perspective that shifts the focus from volitional to motivational aspects of procrastination. In an attempt to demystify the ... [more ▼]

Procrastination is often seen as a self-regulatory failure. We want to offer a perspective that shifts the focus from volitional to motivational aspects of procrastination. In an attempt to demystify the phenomenon, we combine two studies exploring the motivational foundations of procrastination with a study aiming to uncover its implicit normative connotations. Study 1 investigated the link between value orientations and procrastination at a general level, showing that people high in procrastination entertain low achievement and high well-being value orientations. Study 2 investigated the link between self-determination and procrastination within and across daily activities. Low self-determination related to low levels of activity completion and to procrastination in general. Finally, Study 3 investigated the link between value as well as political orientations and perceptions of procrastination. Individuals who favored modern, conservative values were more likely to attribute academic procrastination as personal failure, whereas individuals who endorsed post-modern, liberal values were more likely to consider situational causes of academic procrastination. Against this background, we argue for a less normative view on procrastination and recommend motivational (e.g., goal selection) rather than volitional (e.g., goal implementation) interventions to prevent procrastination. [less ▲]

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See detailUnderstanding Stereophony? Early Dummy Head Research on Sound Localization
Krebs, Stefan UL

Scientific Conference (2017)

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See detailUnderstanding Structure and Bonding of Multilayered Metal-Organic Nanostructures
Egger, David A.; Ruiz, Victor G.; Said, Wissam A. et al

in JOURNAL OF PHYSICAL CHEMISTRY C (2013), 117(6), 3055-3061

For organic and hybrid electronic devices, the physicochemical properties of the contained interfaces play a dominant role. To disentangle the various interactions occurring at such heterointerfaces we ... [more ▼]

For organic and hybrid electronic devices, the physicochemical properties of the contained interfaces play a dominant role. To disentangle the various interactions occurring at such heterointerfaces we here model a complex, yet prototypical, three-component system consisting of a Cu-phthalocyanine (CuPc) film on a 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) monolayer adsorbed on Ag(111). The two encountered interfaces are similar, as in both cases there would be no bonding without van der Waals interactions. Still they are also distinctly different, as only at the Ag-(111) PTCDA interface do massive charge-rearrangements occur. Using recently developed theoretical tools, we show that it has become possible to provide atomistic insight into the physical and chemical processes in this comparatively complex nanostructure distinguishing between interactions involving local rearrangements of the charge density and long-range van der Waals attraction. [less ▲]

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See detailUnderstanding students' performance in a computer-based assessment of complex problem solving. An analysis of behavioral data from computer-generated log files.
Greiff, Samuel UL; Niepel, Christoph UL; Scherer, Ronny et al

in Computers in Human Behavior (2016), 61

Computer-based assessments of complex problem solving (CPS) that have been used in international large-scale surveys require students to engage in an in-depth interaction with the problem environment. In ... [more ▼]

Computer-based assessments of complex problem solving (CPS) that have been used in international large-scale surveys require students to engage in an in-depth interaction with the problem environment. In this, they evoke manifest sequences of overt behavior that are stored in computer-generated logfiles. In the present study, we explored the relation between several overt behaviors, which N=1476 Finnish ninth-grade students (mean age=15.23,SD=.47 years) exhibited when exploring a CPS environment, and their CPS performance. We used the MicroDYN approach to measure CPS and inspected students' behaviors through log-file analyses. Results indicated that students who occasionally observed the problem environment in a noninterfering way in addition to actively exploring it (noninterfering observation) showed better CPS performance, whereas students who showed a high frequency of (potentially unplanned) interventions (intervention frequency) exhibited worse CPS performance. Additionally, both too much and too little time spent on a CPS task (time on task) was associated with poor CPS performance. The observed effects held after controlling for students' use of an exploration strategy that required a sequence of multiple interventions (VOTAT strategy) indicating that these behaviors exhibited incremental effects on CPS performance beyond the use of VOTAT. [less ▲]

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See detailUnderstanding the Babylonian tablet ‘Plimpton 322’ with the decimal system
Perucca, Antonella UL; Stranen, Deborah

E-print/Working paper (2018)

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See detailUnderstanding the Context of Product Development
Gericke, Kilian UL; Meißner, Moritz; Paetzold, Kristin

in Proceedings of 19th International Conference on Engineering Design (2013, August)

Adaptation of design methodologies to the context in which they should be actually applied is seen as a necessity in order to enhance its acceptance and to widen its application. Even though, a context ... [more ▼]

Adaptation of design methodologies to the context in which they should be actually applied is seen as a necessity in order to enhance its acceptance and to widen its application. Even though, a context dependent adaptation is seen as a suitable means to make a substantial improvement of current design methodologies, only few contributions were made over the last years, and it often remains somewhat fuzzy what context actually means. This paper is intended to consolidate the different meanings of context, ways to represent and specify the context and ways to structure the different views on the context. A scheme for categorising influencing factors is presented. The scheme consolidates factors from literature which have been identified as having an influence on design projects. It is seen as a means to support understanding of a design approach and its context. Therefore, the scheme is a consolidation of existing work, which allows a more comprehensive description and analysis of the context than the more specific lists and schemes from literature. [less ▲]

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See detailUnderstanding the differences between how novice and experienced designers approach design tasks
Ahmed, S.; Wallace, K. M.; Blessing, Lucienne UL

in Research in Engineering Design (2003), 14(1), 1-11

Research was undertaken to understand how to provide the most appropriate support for novice designers in engineering design. However, how designers apply their experience and knowledge is not understood ... [more ▼]

Research was undertaken to understand how to provide the most appropriate support for novice designers in engineering design. However, how designers apply their experience and knowledge is not understood and further research in this area is required. This paper describes an observational study to understand how novice and experienced designers approach design tasks. [less ▲]

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See detailUnderstanding the Everyday Use of Head-Worn Computers
Vogl, Anita; Louveton, Nicolas UL; Mccall, Roderick UL et al

in Understanding the Everyday Use of Head-Worn Computers (2015)

Early research on head-worn computers (HWCs) has focused on hardware and specific applications. However, there is little research about the everyday usage of head-worn computers in particular aspects such ... [more ▼]

Early research on head-worn computers (HWCs) has focused on hardware and specific applications. However, there is little research about the everyday usage of head-worn computers in particular aspects such as: context of use, social acceptance across different activities, audiences and interaction techniques. This paper provides insights into the use of head- worn computers by capturing the opinions of novice and expert users through a survey, a three-week diary study, and interviews. The overarching finding is that the context of use is critical, ei- ther due to the need to support micro-interactions, or because the interaction paradigm itself should depend on the context of use. [less ▲]

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See detailUnderstanding the Evolution of Android App Vulnerabilities
Gao, Jun UL; li, li; Bissyande, Tegawendé François D Assise UL et al

in IEEE Transactions on Reliability (2020)

The Android ecosystem today is a growing universe of a few billion devices, hundreds of millions of users and millions of applications targeting a wide range of activities where sensitive information is ... [more ▼]

The Android ecosystem today is a growing universe of a few billion devices, hundreds of millions of users and millions of applications targeting a wide range of activities where sensitive information is collected and processed. Security of communication and privacy of data are thus of utmost importance in application development. Yet, regularly, there are reports of successful attacks targeting Android users. While some of those attacks exploit vulnerabilities in the Android OS, others directly concern application-level code written by a large pool of developers with varying experience. Recently, a number of studies have investigated this phenomenon, focusing however only on a specific vulnerability type appearing in apps, and based on only a snapshot of the situation at a given time. Thus, the community is still lacking comprehensive studies exploring how vulnerabilities have evolved over time, and how they evolve in a single app across developer updates. Our work fills this gap by leveraging a data stream of 5 million app packages to re-construct versioned lineages of Android apps and finally obtained 28;564 app lineages (i.e., successive releases of the same Android apps) with more than 10 app versions each, corresponding to a total of 465;037 apks. Based on these app lineages, we apply state-of- the-art vulnerability-finding tools and investigate systematically the reports produced by each tool. In particular, we study which types of vulnerabilities are found, how they are introduced in the app code, where they are located, and whether they foreshadow malware. We provide insights based on the quantitative data as reported by the tools, but we further discuss the potential false positives. Our findings and study artifacts constitute a tangible knowledge to the community. It could be leveraged by developers to focus verification tasks, and by researchers to drive vulnerability discovery and repair research efforts. [less ▲]

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See detailUnderstanding the evolution of coopetition among SMEs in a wine cluster: A social capital approach
Granata, Julien; Geraudel, Mickaël UL; Nicolosi, Alessandro et al

in International Journal of Entrepreneurship and Small Business (2017), 31(1), 67-84

Research on small and medium-sized enterprises (SMEs) has done little to explore the drivers of coopetition. However, this issue is crucial for practitioners in charge of implementing the coopetition ... [more ▼]

Research on small and medium-sized enterprises (SMEs) has done little to explore the drivers of coopetition. However, this issue is crucial for practitioners in charge of implementing the coopetition process. We address this gap by exploring the drivers of coopetition among SMEs through a longitudinal case study based on 34 interviews along with informal conversations in the French wine cluster of Pic Saint-Loup. We find that the coopetition process (1) occurs in stages driven by specific environmental factors and (2) is facilitated by the social capital of cluster members, particularly the central member (owner-manager), which is key to the success of each coopetition stage. Our results provide a better understanding of wine cluster development and the inducement of SME coopetition. [less ▲]

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See detailUnderstanding the functional neuroanatomy of acquired prosopagnosia
Sorger, Bettina; Goebel, Rainer; Schiltz, Christine UL et al

in NeuroImage (2007), 35(2), 836-852

One of the most remarkable disorders following brain damage is prosopagnosia, the inability to recognize faces. While a number of cases of prosopagnosia have been described at the behavioral level, the ... [more ▼]

One of the most remarkable disorders following brain damage is prosopagnosia, the inability to recognize faces. While a number of cases of prosopagnosia have been described at the behavioral level, the functional neuroanatomy of this face recognition impairment, and thus the brain regions critically involved in normal face recognition, has never been specified in great detail. Here, we used anatomical and functional magnetic resonance imaging (fMRI) to present the detailed functional neuroanatomy of a single case of acquired prosopagnosia (PS; Rossion, B., Caldara, R., Seghier, M., Schuller, A.-M., Lazeyras, F., Mayer, E., 2003a. A network of occipito-temporal face-sensitive areas besides the right middle fusiform gyrus is necessary for normal face processing. Brain 126, 2381-95; Rossion, B., Joyce, C.A., Cottrell, G.W., Tarr, M.J., 2003b. Early lateralization and orientation tuning for face, word, and object processing in the visual cortex. Neuroimage 20, 1609-24) with normal object recognition. First, we clarify the exact anatomical location and extent of PS' lesions in relation to (a) retinotopic cortex, (b) face-preferring regions, and (c) other classical visual regions. PS' main lesion - most likely causing her prosopagnosia - is localized in the posterior part of the right ventral occipitotemporal cortex. This lesion causes a left superior paracentral scotoma, as frequently observed in cases of prosopagnosia. While the borders of the early visual areas in the left hemisphere could be delineated well, the extensive posterior right-sided lesion hampered a full specification of the cortical representation of the left visual field. Using multiple scanning runs, face-preferring activation was detected within the right middle fusiform gyrus (MFG) in the so-called 'fusiform face area' ('FFA'), but also in the left inferior occipital gyrus (left 'OFA'), and in the right posterior superior temporal sulcus (STS). The dorsal part of the lateral occipital complex (LOC) and the human middle temporal cortex (hMT+/V5) were localized bilaterally. The color-preferring region V4/V8 was localized only in the left hemisphere. In the right hemisphere, the posterior lesion spared the ventral part of LOC, a region that may be critical for the preserved object recognition abilities of the patient, and the restriction of her deficit to the category of faces. The presumptive functions of both structurally damaged and preserved regions are discussed and new hypotheses regarding the impaired and preserved abilities of the patient during face and non-face object processing are derived. Fine-grained neurofunctional analyses of brain-damaged single cases with isolated recognition deficits may considerably improve our knowledge of the brain regions critically involved in specific visual functions, such as face recognition. [less ▲]

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See detailUnderstanding the internationalization of higher education as a policy process. The case of Romania
Deca, Ligia UL

Doctoral thesis (2016)

This doctoral thesis analyzes internationalization of higher education in Romania as a both an international norm diffusion process and as a discrete policy process, in a wider context of post-communist ... [more ▼]

This doctoral thesis analyzes internationalization of higher education in Romania as a both an international norm diffusion process and as a discrete policy process, in a wider context of post-communist transition. It is conceived as a study of policy for policy, with the explicit aim of contributing to better decision-making at the national and institutional levels. As such, it is intended to facilitate a strategic pursuit of internationalization strategies in Romania, which may further inform our understanding of other similar (post-communist transition) national cases. The research objective is to understand the internationalization of higher education as a distinct policy process at the national and university level, by using a five-point star model of the policy field, which highlights the multiplicity of actors involved and acts as a ‘cat’s cradle’. A multi-theory approach for higher education governance is used for unpacking the complexity of this policy field. Stakeholder and resource dependency theories are employed for understanding the articulation of the interests, capacities and interactions between the actors, while discursive institutionalism is used to look at the role of ideas (norms) mobilized by actors to influence policy change and to construct policy frames. In terms of scope, the thesis addresses the rationales, drivers and impacts of internationalization of higher education, as well as its strategic use by relevant actors. The conclusion yields that internationalization in Romania, especially at the national level, is more a fruit of the existing context – the overall globalization trends, the Bologna Process and the EU pre- and post-accession policy processes – than a deliberate strategic pursuit based on either foresight or long term planning. Political and economic rationales are predominant, to the detriment of those linked to social and cultural considerations, given the competing pressures linked to the demographic downturn, reduced public funding to universities, the perceived need to ‘catch-up with Europe’ and the global competitiveness imperative. Another finding is that internationalization of higher education has never reached the stage of policy formulation at the national level and in most Romanian universities; it was used as a legitimating discourse within higher education reform, but a genuine commitment to comprehensive internationalization policies was lacking, leading to an over-reliance on European programs and a narrow focus on mobility and research partnerships. When looking at the agents of change, it can be inferred that success in pursuing internationalization activities was mostly influenced by policy entrepreneurs and leadership commitment and continuity, regardless of the institutional profile. At the same time, Romania has proven to be an exceptional laboratory for understanding internationalization as a distinctive public policy process within the higher education sector. This is due to the double centralization legacy of the higher education system (caused by its Napoleonic model of higher education system and the communist influence) and the over-sized influence of international actors in policy reform (e.g. UNESCO CEPES and the World Bank). A number of the overall conclusions, mainly aimed at improving decision-making at the national level, are also potentially relevant for a wider regional audience: the need to minimize the over-reliance on international funds and technical assistance of international organizations; limiting over-regulation based on international norms; and improving the national role in the global discussions on internationalization and fighting double discourse. This latter aspect points to the difficulties of replicating policy concepts across borders in a non-contextualized form, especially when domestic contexts differ significantly from the pioneering setting of a given policy. [less ▲]

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