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See detailGenuine Bianchi modular forms of higher level, at varying weight and discriminant
Rahm, Alexander UL; Tsaknias, Panagiotis UL

E-print/Working paper (in press)

Bianchi modular forms are automorphic forms over an imaginary quadratic field, associated to a Bianchi group. Even though modern studies of Bianchi modular forms go back to the mid 1960's, most of the ... [more ▼]

Bianchi modular forms are automorphic forms over an imaginary quadratic field, associated to a Bianchi group. Even though modern studies of Bianchi modular forms go back to the mid 1960's, most of the fundamental problems surrounding their theory are still wide open. Only for certain types of Bianchi modular forms, which we will call "generic", it is possible at present to develop dimension formulas: They are (twists of) those forms which arise from elliptic cuspidal modular forms via the Langlands base-change procedure, or arise from a quadratic extension of the imaginary quadratic field via automorphic induction (so-called CM-forms). The remaining, non-"generic" Bianchi modular forms are what we call "genuine", and they are of interest for an extension of the modularity theorem (formerly the Taniyama-Shimura conjecture, crucial in the proof of Femat's Last Theorem) to imaginary quadratic fields. In a preceding paper by Rahm and Sengun, an extreme paucity of "genuine" cuspidal Bianchi modular forms has been reported, but those and other computations and were restricted to level One. In this paper, we are extending the formulas for the "generic" Bianchi modular forms to deeper levels, and we are able to spot the first, rare instances of "genuine" forms at deeper level and heavier weight. [less ▲]

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See detailYolanda von Vianden und das Yolanda-Epos
Sieburg, Heinz UL

E-print/Working paper (in press)

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See detailThe edge-based strain smoothing method for compressible and nearly incompressible non-linear elasticity for solid mechanics
Lee, Chang-Kye; Mihai, L. Angela; Kerfriden, Pierre et al

E-print/Working paper (in press)

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See detailThe Farrell--Tate and Bredon homology for PSL_4(Z) and other arithmetic groups
Bui, Anh Tuan; Rahm, Alexander UL; Wendt, Matthias

E-print/Working paper (in press)

We provide some new computations of Farrell--Tate and Bredon (co)homology for arithmetic groups. For calculations of Farrell--Tate or Bredon homology, one needs cell complexes where cell stabilizers fix ... [more ▼]

We provide some new computations of Farrell--Tate and Bredon (co)homology for arithmetic groups. For calculations of Farrell--Tate or Bredon homology, one needs cell complexes where cell stabilizers fix their cells pointwise. We provide an algorithm computing an efficient subdivision of a complex to achieve this rigidity property. Applying this algorithm to available cell complexes for PSL_4(Z) and PGL_3(Z[i]) provides computations of Farrell--Tate cohomology for small primes as well as the Bredon homology for the classifying spaces of proper actions with coefficients in the complex representation ring. On the other hand, to check correctness of the computer calculations, we describe the Farrell--Tate cohomology in some rank-one cases, using Brown's complex and a number-theoretic description of the conjugacy classification of cyclic subgroups. [less ▲]

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See detailOn the Cohomological Crepant Resolution Conjecture for the complexified Bianchi orbifolds
Perroni, Fabio; Rahm, Alexander UL

E-print/Working paper (in press)

We give formulae for the Chen--Ruan orbifold cohomology for the orbifolds given by a Bianchi group acting on complex hyperbolic 3-space. The Bianchi groups are the arithmetic groups PSL_2(A), where A is ... [more ▼]

We give formulae for the Chen--Ruan orbifold cohomology for the orbifolds given by a Bianchi group acting on complex hyperbolic 3-space. The Bianchi groups are the arithmetic groups PSL_2(A), where A is the ring of integers in an imaginary quadratic number field. The underlying real orbifolds which help us in our study, given by the action of a Bianchi group on real hyperbolic 3-space (which is a model for its classifying space for proper actions), have applications in physics. We then prove that, for any such orbifold, its Chen-Ruan orbifold cohomology ring is isomorphic to the usual cohomology ring of any crepant resolution of its coarse moduli space. By vanishing of the quantum corrections, we show that this result fits in with Ruan's Cohomological Crepant Resolution Conjecture. [less ▲]

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See detailA co-located partitions strategy for parallel CFD-DEM couplings
Pozzetti, Gabriele UL; Besseron, Xavier UL; Rousset, Alban UL et al

E-print/Working paper (in press)

In this work, a new partition-collocation strategy for the parallel execution of CFD–DEM couplings is investigated. Having a good parallel performance is a key issue for an Eulerian-Lagrangian software ... [more ▼]

In this work, a new partition-collocation strategy for the parallel execution of CFD–DEM couplings is investigated. Having a good parallel performance is a key issue for an Eulerian-Lagrangian software that aims to be applied to solve industrially significant problems, as the computational cost of these couplings is one of their main drawback. The approach presented here consists in co-locating the overlapping parts of the simulation domain of each software on the same MPI process, in order to reduce the cost of the data exchanges. It is shown how this strategy allows reducing memory consumption and inter-process communication between CFD and DEM to a minimum and therefore to overcome an important parallelization bottleneck identified in the literature. Three benchmarks are proposed to assess the consistency and scalability of this approach. A coupled execution on 280 cores shows that less than 0.1% of the time is used to perform inter-physics data exchange. [less ▲]

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See detailData Filtering Rules in Option Valuation
Bams, Dennis; Blanchard, Gildas; Lehnert, Thorsten UL

E-print/Working paper (2018)

The choice of data filtering rules are, next to model selection and parameter calibration, an important step in an option pricing exercise. We illustrate the implications of data filtering rules, by ... [more ▼]

The choice of data filtering rules are, next to model selection and parameter calibration, an important step in an option pricing exercise. We illustrate the implications of data filtering rules, by investigating three alternative renowned filtering rules in the context of pricing European S&P 500 index options. Different filtering rules result in strongly diverging samples, which carry different information and therefore lead to different parameter estimates. This is illustrated for the Ad Hoc Black-Scholes model. No filtering rule is, in terms of pricing performance, superior on the whole range of options. Instead, each filtering rule is specialized toward better pricing of options types that were included in the calibration sample at the costs of excluded options. Included options are unable to perfectly represent the properties and characteristics of excluded options. In particular, option prices are heterogeneous in the maturity dimension, which is a major driving force underlying the impact of exclusion filters on pricing performance. Additionally, small deviations from the put-call parity strongly affect parameter estimates as well as the accompanying pricing performance. These results emphasize the prominent role of filtering rules as an important implicit choice for an option pricing model calibration. [less ▲]

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See detailModel Uncertainty and Pricing Performance in Option Valuation
Bams, Dennis; Blanchard, Gildas; Lehnert, Thorsten UL

E-print/Working paper (2018)

The objective of this paper is to evaluate option pricing model performance at the cross sectional level. For this purpose, we propose a statistical framework, in which we in particular account for the ... [more ▼]

The objective of this paper is to evaluate option pricing model performance at the cross sectional level. For this purpose, we propose a statistical framework, in which we in particular account for the uncertainty associated with the reported pricing performance. Instead of a single figure, we determine an entire probability distribution function for the loss function that is used to measure option pricing model performance. This methodology enables us to visualize the effect of parameter uncertainty on the reported pricing performance. Using a data driven approach, we confirm previous evidence that standard volatility models with clustering and leverage effects are sufficient for the option pricing purpose. In addition, we demonstrate that there is short-term persistence but long-term heterogeneity in cross-sectional option pricing information. This finding has two important implications. First, it justifies the practitioner’s routine to refrain from time series approaches, and instead estimate option pricing models on a cross-section by cross-section basis. Second, the long term heterogeneity in option prices pinpoints the importance of measuring, comparing and testing option pricing model for each cross-section separately. To our knowledge no statistical testing framework has been applied to a single cross-section of option prices before. We propose a methodology that addresses this need. The proposed framework can be applied to a broad set of models and data. In the empirical part of the paper, we show by means of example, an application that uses a discrete time volatility model on S&P 500 European options. [less ▲]

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See detailIslamic Banking and Economic Growth: New Evidence
Kchouri, Bilal UL; Lehnert, Thorsten UL

E-print/Working paper (2018)

While extensive work has shown that conventional banking development is generally conducive to economic growth, there are only a limited number of studies that investigate the impact of Islamic banking ... [more ▼]

While extensive work has shown that conventional banking development is generally conducive to economic growth, there are only a limited number of studies that investigate the impact of Islamic banking. Importantly, the literature on conventional banking claims that a reverse causality from economy performance to banking may exists, but existing studies on Islamic banking fail to address this potential endogeneity problem. This paper tackles this problem and explores the relationship between Islamic banking development and economic performance in a sample of 32 developed and developing countries based on data spanning the 2000 to 2016 period. The findings show that, although Islamic banks are considered small relative to the total size of the financial sector, Islamic banking is positively correlated with economic growth even after controlling for financial structure, macroeconomic factors and other variables. The outcome is robust across different econometric specifications like pooling OLS, fixed effects, panel data with over-identified GMM, and dynamic difference GMM. The results are confirmed on two different indicators of Islamic banking and hold for different time periods. [less ▲]

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See detailAsset Pricing Implications of Risk Governance
Lehnert, Thorsten UL

E-print/Working paper (2018)

Some of the world’s poorest countries have demonstrated that political leadership and practical policies make a difference. Good governance could help to strengthen accountability, enhance participation ... [more ▼]

Some of the world’s poorest countries have demonstrated that political leadership and practical policies make a difference. Good governance could help to strengthen accountability, enhance participation and break down inequalities. Furthermore, a country’s quality of government has a positive effect on the development of its financial market and equity returns. In particular, it lowers equity volatility and, therefore, the costs of equity financing, which further helps to reduce inequalities. While price jumps are prevalent in stock markets all over the world, previous literature provides little guidance about the international nature of jumps and its relationship with country characteristics. Jumps are found to be far less systematic than the smooth (non-jump) component of country price indexes. Hence, if jumps are more idiosyncratic, risk governance should primarily affect the jump risk component of stock market volatility. This is good news for international investors, because diversification provides insurance against jumps. Relying on an equilibrium asset-pricing model in an economy under jump diffusion, I decompose the moments of the returns of international stock markets into a diffusive (systematic) risk and a (idiosyncratic) jump risk part. Using stock market data for a balanced panel of 52 countries, my results suggest that risk governance is an important determinant of (idiosyncratic) jump risk. Stock markets in poorly governed countries are characterized by higher volatility and more negative return asymmetry, primarily driven by the higher jump risk. Among the different governance indicators analyzed, the regulatory quality, the government effectiveness and the control of corruption appear to be most important. Results are robust to the inclusion of various controls for other country- or market-specific characteristics. My results have important policy implications. [less ▲]

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See detailMarket Skewness Risk, Risk Aversion and the Cross-Section of Stock Returns
Bams, Dennis; Honarvar, Iman; Lehnert, Thorsten UL

E-print/Working paper (2018)

Previous research suggests that the cross section of stock returns has substantial exposure to risks captured by higher moments of market returns, implied by S&P500 index option prices. However, assuming ... [more ▼]

Previous research suggests that the cross section of stock returns has substantial exposure to risks captured by higher moments of market returns, implied by S&P500 index option prices. However, assuming that risk aversion is time-varying, a risk-based explanation would suggest that the exposure is priced in periods of high risk aversion, while it is not necessarily priced/weaker in periods of low risk aversion. We find that for market skewness and kurtosis, this hypothesis is not supported by the data. We find that each of the higher moment prices of risk is time-varying and has significantly different patterns under different market conditions, proxied by a measure of investors’ relative risk aversion. In particular, in line with our reasoning, our results suggest that only in down-markets (high risk aversion periods), the exposure to the market volatility innovations is priced significantly negative in the cross-section of stocks, while it is not priced in up-markets (low risk aversion periods). In contrast, we find that in down-markets, market skewness and kurtosis are not priced risk factors, while the price of market skewness risk is significantly negative and the price of kurtosis risk is positive in up-markets. However, the previously reported results for skewness and kurtosis are counterintuitive, strictly violate the risk compensation principles and, therefore, do not support a risk-based explanation. The results persist even after controlling for the Fama-French and Carhart factors. [less ▲]

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See detailTabakkonsum von Schülern in Luxemburg
Kern, Matthias Robert UL; Heinz, Andreas UL; Residori, Caroline UL et al

E-print/Working paper (2018)

In der HBSC-Studie 2014 wurden Fragen zum Tabakkonsum gestellt. Von den 11-12-Jährigen sind 2 % laut eigenen Angaben Raucher, in der Altersgruppe 17-18 steigt dieser Anteil auf knapp über ein Drittel. Bis ... [more ▼]

In der HBSC-Studie 2014 wurden Fragen zum Tabakkonsum gestellt. Von den 11-12-Jährigen sind 2 % laut eigenen Angaben Raucher, in der Altersgruppe 17-18 steigt dieser Anteil auf knapp über ein Drittel. Bis zum Alter von 14 Jahren ist der Anteil der regelmäßigen Raucher (d.h. sie rauchen mindestens einmal pro Woche) bei Jungen und Mädchen etwa gleich hoch. In der Altersgruppe 17-18 rauchen 32 % der männlichen Jugendlichen regelmäßig, aber nur 23 % der weiblichen Jugendlichen. Im Enseignement secondaire technique ist der Anteil der regelmäßigen Raucher in allen Altersgruppen ungefähr doppelt so hoch wie im Enseignement secondaire. Die Hälfte der Raucher hat mit 14 Jahren oder noch früher mit dem Rauchen angefangen, daher sollte frühzeitig über die Gefahren des Rauchens aufgeklärt werden. [less ▲]

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See detailFrühstückgewohnheiten
Residori, Caroline UL; van Duin, Claire UL; Kern, Matthias Robert UL et al

E-print/Working paper (2018)

In der HBSC-Studie 2014 wurden die Schüler gefragt, ob sie an allen Schultagen frühstücken. Tägliches Frühstücken nimmt mit dem Alter ab: Während im Alter von 11-12 rund zwei Drittel der Schüler täglich ... [more ▼]

In der HBSC-Studie 2014 wurden die Schüler gefragt, ob sie an allen Schultagen frühstücken. Tägliches Frühstücken nimmt mit dem Alter ab: Während im Alter von 11-12 rund zwei Drittel der Schüler täglich frühstücken, sind es weniger als die Hälfte der Schüler im Alter von 17-18. Im Alter von 11-16 ist tägliches Frühstücken bei Jungen häufiger verbreitet als bei Mädchen, in der Altersgruppe 17-18 gibt es keine Unterschiede. Die befragten Schüler frühstücken umso eher täglich, je höher der Wohlstand der Familie ist, in der sie aufwachsen. Tägliches Frühstücken ist bei Schülern im Fondamental häufiger verbreitet als bei Schülern an Sekundarschulen. Innerhalb der Sekundarschulen ist tägliches Frühstücken am weitesten verbreitet im Enseignement secondaire und am seltensten im Modulaire. [less ▲]

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See detail"Was hältst du zurzeit von der Schule?"
van Duin, Claire UL; Heinz, Andreas UL; Kern, Matthias Robert UL et al

E-print/Working paper (2018)

Die Schule ist ein wichtiger Ort der Sozialisation, an dem die Schüler viel Zeit verbringen. Positive Erfahrungen mit der Schule können die soziale und gesundheitliche Entwicklung der Schüler fördern ... [more ▼]

Die Schule ist ein wichtiger Ort der Sozialisation, an dem die Schüler viel Zeit verbringen. Positive Erfahrungen mit der Schule können die soziale und gesundheitliche Entwicklung der Schüler fördern, negative Erfahrungen können die Entwicklung beeinträchtigen. Daher wurde in der HBSC-Studie 2014 gefragt, wie sehr die Schüler ihre Schule mögen. Von den 11-12-Jährigen mögen 30 % die Schule sehr, weitere 52 % mögen sie einigermaßen. In der Gruppe der 15-16-Jährigen mögen 11 % die Schule sehr und 15 % mögen sie überhaupt nicht. Dementsprechend mögen Schüler des Fondamental ihre Schule eher als Schüler an Sekundarschulen. Zwischen den Schultypen Secondaire, Secondaire technique und Modulaire gibt es hingegen kaum Unterschiede. Je mehr sich Schüler durch die Schularbeit gestresst fühlen, desto eher mögen sie die Schule nicht. Sie mögen sie auch dann eher nicht, wenn sie vermuten, dass ihre Lehrer sie für leistungsschwach halten. Je weniger die Schüler ihre Schule mögen, desto mehr Gesundheitsbeschwerden berichten sie. [less ▲]

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See detailAlkoholkonsum von Schülern in Luxemburg
Catunda, Carolina UL; van Duin, Claire UL; Kern, Matthias Robert UL et al

E-print/Working paper (2018)

In der HBSC-Studie 2014 wurden die Schüler gefragt, ob sie in den vergangenen 30 Tagen Alkohol getrunken haben. Von den 11-12-Jährigen gaben dies 4 % an, in der Altersgruppe 17-18 waren es 68 %. Bis zum ... [more ▼]

In der HBSC-Studie 2014 wurden die Schüler gefragt, ob sie in den vergangenen 30 Tagen Alkohol getrunken haben. Von den 11-12-Jährigen gaben dies 4 % an, in der Altersgruppe 17-18 waren es 68 %. Bis zum Alter von 16 Jahren geben Jungen und Mädchen ähnlich häufig Alkoholkonsum an. In der Altersgruppe 17-18 haben männliche Jugendliche häufiger als weibliche Jugendliche Alkohol getrunken (73 % vs. 63 % in den vergangenen 30 Tagen). Ältere Jugendliche aus wohlhabenden Familien gaben häufiger Alkoholkonsum an als Jugendliche aus Familien mit geringem Wohlstand (74 % vs. 63 %). Zudem konsumieren die 15-18-jährigen Schüler des Enseignement secondaire häufiger Alkohol als die Schüler des Enseignement secondaire technique. Verglichen mit 15-jährigen Schülern aus anderen Ländern geben die luxemburgischen Schüler seltener an, bereits zweimal oder häufiger in ihrem Leben betrunken gewesen zu sein. [less ▲]

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See detailGeschlechtsverkehr und Verhütung
van Duin, Claire UL; Heinz, Andreas UL; Kern, Matthias Robert UL et al

E-print/Working paper (2018)

In der HBSC-Studie 2014 wurden den Schülern von Sekundarschulen Fragen zu Sexualität und Verhütung gestellt. Von den männlichen Jugendlichen im Alter von 15 Jahren gaben 27 % an, schon Geschlechtsverkehr ... [more ▼]

In der HBSC-Studie 2014 wurden den Schülern von Sekundarschulen Fragen zu Sexualität und Verhütung gestellt. Von den männlichen Jugendlichen im Alter von 15 Jahren gaben 27 % an, schon Geschlechtsverkehr gehabt zu haben, bei den weiblichen Jugendlichen liegt der Anteil mit 22 % etwas darunter. Von den 18-Jährigen gaben jeweils rund zwei Drittel an, schon mit jemandem geschlafen zu haben. Schüler des Enseignement secondaire technique geben häufiger als ihre Altersgenossen im Enseignement secondaire an, schon Geschlechtsverkehr gehabt zu haben. Bei ihrem letzten Geschlechtsverkehr haben 68 % mit Kondomen verhütet und 55 % mit der Pille. Jungen wussten häufiger als die Mädchen nicht, welche Verhütungsmittel sie genutzt haben. Dies deutet darauf hin, dass Jungen in Verhütungsfragen sorgloser sind und ein Teil von ihnen Verhütung als Frauensache ansieht. Rund 3 % der sexuell aktiven Schüler gaben ein riskantes Verhütungsverhalten an: Sie haben beim letzten Geschlechtsverkehr mittels Koitus interruptus verhütet und sie haben auf andere Methoden verzichtet oder sie wussten nicht, ob der Partner bzw. die Partnerin zusätzlich eine sichere Methode einsetzt. [less ▲]

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See detailCannabiskonsum von Schülern in Luxemburg
Heinz, Andreas UL; Kern, Matthias Robert UL; Residori, Caroline UL et al

E-print/Working paper (2018)

In der HBSC-Studie 2014 wurde nach dem Cannabiskonsum der Schüler gefragt. 38 % der 17-18-Jährigen haben laut eigenen Angaben mindestens einmal in ihrem Leben Cannabis probiert, in den vergangenen 30 ... [more ▼]

In der HBSC-Studie 2014 wurde nach dem Cannabiskonsum der Schüler gefragt. 38 % der 17-18-Jährigen haben laut eigenen Angaben mindestens einmal in ihrem Leben Cannabis probiert, in den vergangenen 30 Tagen haben in dieser Altersgruppe 15 % Cannabis konsumiert. Der „Probierkonsum“ ist somit deutlich weiter verbreitet als der regelmäßige Konsum. Je älter die Schüler sind, desto höher ist der Anteil der Cannabiskonsumenten, wobei der Anstieg bei den Jungen größer ist als bei den Mädchen. Von den 17-18-Jährigen haben 20 % der Jungen in den vergangenen 30 Tagen Cannabis genommen, aber nur 11 % der Mädchen. Die Häufigkeit des Konsums unterscheidet sich kaum je nach Wohlstand der Familie oder zwischen dem Enseignement secondaire und dem Enseignement secondaire technique. Ein Viertel der Konsumenten hat bis zum Alter von rund 14 Jahren mit dem Konsum angefangen, daher sollte die Prävention frühzeitig einsetzen. [less ▲]

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See detailSchulischer Stress
Heinz, Andreas UL

E-print/Working paper (2018)

In der HBSC-Studie wurde den Schülern die Frage gestellt: „Fühlst du dich durch die Schularbeit gestresst?“ Insgesamt antworteten 21 % „überhaupt nicht“, 44 % „ein bisschen“, 19 % „einigermaßen“ und 17 ... [more ▼]

In der HBSC-Studie wurde den Schülern die Frage gestellt: „Fühlst du dich durch die Schularbeit gestresst?“ Insgesamt antworteten 21 % „überhaupt nicht“, 44 % „ein bisschen“, 19 % „einigermaßen“ und 17 % „sehr“. Je älter die Schüler sind, desto häufiger geben sie an, unter Schulstress zu leiden. Unter den älteren Schülern sind Mädchen eher von Schulstress betroffen als Jungen. Am häufigsten fühlen sich Schüler des Enseignement secondaire von der Schularbeit gestresst, am seltensten Schüler des Fondamentals, Schüler des Secondaire technique liegen dazwischen. Schüler, die davon ausgehen, dass ihre Lehrer sie für überdurchschnittlich leistungsfähig halten, geben seltener Schulstress an als Schüler, die annehmen, dass ihre Lehrer sie für durchschnittlich oder unterdurchschnittlich leistungsfähig halten. Schüler, die einen stärkeren Schulstress angeben, geben auch an, unter mehr Gesundheitsbeschwerden zu leiden (Kopf-, Bauch- und Rückenschmerzen, Traurigkeit, Gereiztheit, Nervosität, Einschlafschwierigkeiten und Schwindel). [less ▲]

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See detailPortability of Student Benefits in the European Union - The Luxembourg System
Silga, Janine UL

E-print/Working paper (2018)

Since its creation, Luxembourg’s system of financial aid for higher (university) studies has set as its primary objective the increase of the proportion of its resident population holding a higher ... [more ▼]

Since its creation, Luxembourg’s system of financial aid for higher (university) studies has set as its primary objective the increase of the proportion of its resident population holding a higher education degree. However, the fact that Luxembourg did not have its own university system until 2003 made this country even more dependent on other European countries to fulfil this policy objective. This explains why the portability of national financial assistance for higher education was crucial to achieve it. In the European Union (EU) context, the portability – or exportability – of student grants or loans may be defined as the faculty for students to ‘export’ such benefits to a Member State that is different from the one which allocates them. Portability is also the reason why the Luxembourg system falls into the scope of EU law, since it may interfere with equal treatment between workers all the more so, as frontier workers account for more than 45% of the country’s labour force. These peculiarities provide the background for the three decisions of the Court of Justice of the EU (CJEU) on the portability of financial aid for higher studies for children of frontier workers that lie at the heart of this paper. It will start by briefly highlighting the evolution of Luxembourg’s system of financial aid for higher education and present its main features. Then, it will show that despite the recent clarifications given by the CJEU in the last two cases of 2016, several issues remain unanswered, both from an EU and national law perspective. [less ▲]

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See detailA Proof of Entropy Minimization for Outputs in Deletion Channels via Hidden Word Statistics
Atashpendar, Arash UL; Mestel, David; Roscoe, A.W. (Bill) et al

E-print/Working paper (2018)

From the output produced by a memoryless deletion channel from a uniformly random input of known length n, one obtains a posterior distribution on the channel input. The difference between the Shannon ... [more ▼]

From the output produced by a memoryless deletion channel from a uniformly random input of known length n, one obtains a posterior distribution on the channel input. The difference between the Shannon entropy of this distribution and that of the uniform prior measures the amount of information about the channel input which is conveyed by the output of length m, and it is natural to ask for which outputs this is extremized. This question was posed in a previous work, where it was conjectured on the basis of experimental data that the entropy of the posterior is minimized and maximized by the constant strings 𝟶𝟶𝟶… and 𝟷𝟷𝟷… and the alternating strings 𝟶𝟷𝟶𝟷… and 𝟷𝟶𝟷𝟶… respectively. In the present work we confirm the minimization conjecture in the asymptotic limit using results from hidden word statistics. We show how the analytic-combinatorial methods of Flajolet, Szpankowski and Vall\'ee for dealing with the hidden pattern matching problem can be applied to resolve the case of fixed output length and n→∞, by obtaining estimates for the entropy in terms of the moments of the posterior distribution and establishing its minimization via a measure of autocorrelation. [less ▲]

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See detailBetween European Precaution and National Compensation : The Disourses of Risk Management A Critical Analysis of Giovanni Pesce and Others v. Presidenza del Consiglio dei Ministri – Dipartimento della Protezione Civile and Others
Dufour, Pascale UL

E-print/Working paper (2018)

Contemporary society can undisputably be characterized, following Ulrich Beck, as a risk society. Indeed, catastrophic risks multiply themselves, and hence also need to be managed. This paper addresses ... [more ▼]

Contemporary society can undisputably be characterized, following Ulrich Beck, as a risk society. Indeed, catastrophic risks multiply themselves, and hence also need to be managed. This paper addresses more generally the question of how and by whom decision making regarding risk management is made in the European Union. More precisely, it provides a critical analysis of the legal discourse, on the one hand, on the use of the precautionary principle in risk management, and, on the other hand, on compensation of individuals that suffer financial losses related to decisions that are taken on the behalf of this principle. This critic will here be illustrated through an analysis of the Giovanni Pesce and Others v. Presidenza del Consiglio dei Ministri – Dipartimento della Protezione Civile and Others case. [less ▲]

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See detailWozu Mittelalterforschung? Zum 30. Jubiläum des CLUDEM
Pauly, Michel UL

E-print/Working paper (2018)

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See detailCharacterizations of biselective operations
Devillet, Jimmy UL; Kiss, Gergely UL

E-print/Working paper (2018)

Let X be a nonempty set and let i,j in {1,2,3,4}. We say that a binary operation F:X^2 -> X is (i,j)-selective if F(F(x_1,x_2),F(x_3,x_4)) = F(x_i,x_j), for all x_1,x_2,x_3,x_4 in X. In this paper we ... [more ▼]

Let X be a nonempty set and let i,j in {1,2,3,4}. We say that a binary operation F:X^2 -> X is (i,j)-selective if F(F(x_1,x_2),F(x_3,x_4)) = F(x_i,x_j), for all x_1,x_2,x_3,x_4 in X. In this paper we provide characterizations of the class of (i,j)-selective operations. We also investigate some subclasses by adding algebraic properties such as associativity or bisymmetry. [less ▲]

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See detailProperness for circle packings and Delaunay circle patterns on complex projective structures
Schlenker, Jean-Marc UL; Yarmola, Andrew UL

E-print/Working paper (2018)

We consider circle packings and, more generally, Delaunay circle patterns - arrangements of circles arising from a Delaunay decomposition of a finite set of points - on surfaces equipped with a complex ... [more ▼]

We consider circle packings and, more generally, Delaunay circle patterns - arrangements of circles arising from a Delaunay decomposition of a finite set of points - on surfaces equipped with a complex projective structure. Motivated by a conjecture of Kojima, Mizushima and Tan, we prove that the forgetful map sending a complex projective structure admitting a circle packing with given nerve (resp. a Delaunay circle pattern with given nerve and intersection angles) to the underlying complex structure is proper. [less ▲]

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See detailAssociative, idempotent, symmetric, and order-preserving operations on chains
Devillet, Jimmy UL; Teheux, Bruno UL

E-print/Working paper (2018)

We characterize the associative, idempotent, symmetric, and order-preserving operations on (finite) chains in terms of properties of (the Hasse diagram of) their associated semilattice order. In ... [more ▼]

We characterize the associative, idempotent, symmetric, and order-preserving operations on (finite) chains in terms of properties of (the Hasse diagram of) their associated semilattice order. In particular, we prove that the number of associative, idempotent, symmetric, and order-preserving operations on an n-element chain is the nth Catalan number. [less ▲]

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See detailLes problèmes de santé des élèves luxembourgeois
Heinz, Andreas UL; Kern, Matthias Robert UL; Catunda, Carolina UL et al

E-print/Working paper (2018)

Dans le cadre de l’enquête HBSC 2014, réalisée dans plusieurs pays de l’Union européenne, les élèves interrogés devaient indiquer la fréquence à laquelle ils souffraient des huit problèmes de santé ... [more ▼]

Dans le cadre de l’enquête HBSC 2014, réalisée dans plusieurs pays de l’Union européenne, les élèves interrogés devaient indiquer la fréquence à laquelle ils souffraient des huit problèmes de santé suivants : maux de tête ou de dos, douleurs abdominales, tristesse, irritabilité, nervosité, difficultés à s’endormir ou vertiges. Le résultat démontre que 41 % des élèves affirmaient avoir plusieurs fois par semaine voire quotidiennement au moins deux des huit problèmes précités. Les filles souffrent plus fréquemment de problèmes de santé que les garçons, ainsi que les élèves plus âgés comparativement aux plus jeunes. En outre, des enfants issus de familles avec un niveau socio-économique faible ont plus souvent des problèmes de santé que les enfants des familles ayant un niveau socio-économique élevé. Enfin, les élèves du secondaire technique et du modulaire souffrent plus fréquemment de problèmes de santé que les élèves de l’enseignement fondamental et du secondaire. [less ▲]

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See detailLe surpoids chez les élèves au Luxembourg
Kern, Matthias Robert UL; Heinz, Andreas UL; Catunda, Carolina UL et al

E-print/Working paper (2018)

Dans le cadre de l’enquête HBSC 2014, réalisée dans plusieurs pays de l’Union européenne, les élèves étaient interrogés concernant leur taille et leur poids pour permettre de calculer leur indice de masse ... [more ▼]

Dans le cadre de l’enquête HBSC 2014, réalisée dans plusieurs pays de l’Union européenne, les élèves étaient interrogés concernant leur taille et leur poids pour permettre de calculer leur indice de masse corporelle (IMC). Parmi les participants, 13 % sont trop maigres, 72 % ont un poids normal, 13 % sont en surpoids et 3 % sont obèses. En comparant avec les autres pays, il y a relativement peu d’enfants de 11 ans au Luxembourg en surpoids. La proportion des élèves de 15 ans en situation de surpoids se trouve au niveau de la moyenne internationale. Les enfants issus de familles de niveau socio-économique élevé ont un risque plus faible d’être en surpoids que ceux des familles avec un niveau plus bas. Les élèves de l’enseignement fondamental et du secondaire sont moins susceptibles d’être en surpoids que ceux du secondaire technique et du modulaire. [less ▲]

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See detailLa satisfaction de vie des élèves au Luxembourg
Kern, Matthias Robert UL; Heinz, Andreas UL; Catunda, Carolina UL et al

E-print/Working paper (2018)

Dans le cadre de l’enquête HBSC 2014, les élèves devaient indiquer à quel point ils étaient satisfaits de leur vie. La valeur « 0 » signifiait « la plus mauvaise vie possible » et la valeur « 10 » ... [more ▼]

Dans le cadre de l’enquête HBSC 2014, les élèves devaient indiquer à quel point ils étaient satisfaits de leur vie. La valeur « 0 » signifiait « la plus mauvaise vie possible » et la valeur « 10 » signifiait « la meilleur vie possible ». Parmi les participants du Luxembourg, 82 % ont indiqué une valeur de 6 ou plus, ce qui est défini comme étant « un niveau de satisfaction de vie élevé ». Pour 10 % d’entre eux, la satisfaction de vie était cotée avec la valeur moyenne de 5 et les 8 % restants ont indiqué une valeur inférieure à 5. La satisfaction de vie des filles moins âgées est plus élevée que celle des filles plus âgées. Chez les garçons, par contre, la satisfaction de vie reste pratiquement constante de 11 à 18 ans. Les garçons sont plus satisfaits de leur vie que les filles, ainsi que les enfants issus des familles avec un niveau socio-économique élevé, en comparaison avec ceux issus des familles ayant un niveau socio-économique faible. La satisfaction de vie est également liée aux problèmes de santé : les élèves qui indiquent souffrir fréquemment de douleurs, de tristesse, de mauvaise humeur / d’irritabilité, de nervosité, de problèmes à s’endormir ou de vertiges sont moins souvent satisfaits de leur vie. [less ▲]

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See detailWWI: Kosakenmütze und roter Stern: Russische Gefangene in Luxemburg 1918
Ganschow, Inna UL

E-print/Working paper (2018)

Die vorliegende Teiluntersuchung beschäftigt sich mit den 3.100 russischen Kriegsgefangenen, die 1918 Luxemburg passierten. Etwa 300 blieben nachweislich in Luxemburg, da die sowjetische Ideologie in ... [more ▼]

Die vorliegende Teiluntersuchung beschäftigt sich mit den 3.100 russischen Kriegsgefangenen, die 1918 Luxemburg passierten. Etwa 300 blieben nachweislich in Luxemburg, da die sowjetische Ideologie in ihrer neuen Heimat, die nun Russische Sowjetische Föderative Sozialistische Republik hieß, sie nicht ansprach. In einer mikrohistorischen Perspektive werden mehrere Schicksale vorgeführt, anhand derer man zum einen die Bedingungen dieser Emigration versteht, die sich zwar auf neutralen Boden vollzog, jedoch unter der stetigen Verfolgung durch die deutsche Armee, die die Unabhängigkeit Luxemburgs wenig kümmerte. Zum anderen wird gezeigt, wie “Russisch” immer mehr mit “Kommunistisch” assoziiert wurde und alle Russen unter Verdacht standen, “rot” zu sein. [less ▲]

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See detailRussians in Luxembourg: Русские в Вильтце - история первых эмигрантов
Ganschow, Inna UL

E-print/Working paper (2018)

Люксембургская русская община ведет свой отсчет с 1927 года – десятой годовщины Февральской, а потом и Октябрьской, революции. Девяносто лет назад прибыли эмигранты, прошедшие Гражданскую войну и ... [more ▼]

Люксембургская русская община ведет свой отсчет с 1927 года – десятой годовщины Февральской, а потом и Октябрьской, революции. Девяносто лет назад прибыли эмигранты, прошедшие Гражданскую войну и Крымскую эвакуацию 1920-го, положившую конец сопротивлению Белого движения на Юге России. Приехали в Люксембург, думая, что ненадолго, а остались... навсегда. [less ▲]

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See detailRussians in Luxembourg, WWII: Поиски старого друга
Ganschow, Inna UL

E-print/Working paper (2018)

Спустя семьдесят лет после окончания Второй мировой войны бывший люксембургский военнопленный решил найти своего старого русского друга, которого пригнали на принудительные работы в сталелитейной ... [more ▼]

Спустя семьдесят лет после окончания Второй мировой войны бывший люксембургский военнопленный решил найти своего старого русского друга, которого пригнали на принудительные работы в сталелитейной промышленности и сельском хозяйстве Люксембурга наравне с другими 4.000 узниками. Судьбы двух пленных переплелись, как они переплетутся между советскими и люксембургскими поданными в Европе еще не раз ... [less ▲]

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See detailMore Necessary and Less Sufficient: An Age-Period-Cohort Approach to Overeducation in Comparative Perspective
Bar-Haim, Eyal UL; Chauvel, Louis UL; Hartung, Anne UL

E-print/Working paper (2018)

In many countries, the skilled labor market has lagged behind educational expansion. As a result of increased competition, younger cohorts of the highly educated face decreasing returns to education or ... [more ▼]

In many countries, the skilled labor market has lagged behind educational expansion. As a result of increased competition, younger cohorts of the highly educated face decreasing returns to education or overeducation. Surprisingly, decreasing occupational outcomes do not coincide empirically with the economic returns among those with tertiary education. Regarding the process of changes in economic returns to education based on cohort transformations, we expect that the expansion of tertiary education affects specific cohorts, which find themselves facing more labor market competition. As a result, the economic returns to education should decrease over cohorts even though they remain stable and even increase during the same period. To study this process, we model economic returns with a new Age-Period- Cohort-Trended-Lag (APCTLAG) method, which allows comparing the gap in economic returns between tertiary and less than tertiary education over cohorts. Using the Luxembourg Income Study (LIS), we analyze trends over three decades in 12 countries. Our results confirm that educational returns for tertiary education have declined over time, even though the gap between the educated and the less educated has remained similar in most of the countries. For younger cohorts, tertiary education has become more necessary to survive in the competitive labor market, but the actual economic returns to it have decreased - making tertiary education less sufficient than before. [less ▲]

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See detailLe régime d’Etat providence joue un rôle dans le bien-être
Samuel, Robin UL; Hadjar, Andreas UL; Brunel, Valentin

E-print/Working paper (2018)

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See detailThe Global Triumph of the Research University: A Driving Force of Science Production
Baker, David P.; Dusdal, Jennifer UL; Powell, Justin J W UL et al

E-print/Working paper (2018)

The demand for higher education in countries around the world has never been higher. This increase in education levels has generated many benefits to society, including more knowledgeable citizens ... [more ▼]

The demand for higher education in countries around the world has never been higher. This increase in education levels has generated many benefits to society, including more knowledgeable citizens, advanced economies, and enhanced longevity. We have also seen countries and universities invest heavily in science, technology, engineering, and mathematics (STEM), including health (STEM+) research and scientific output. This has resulted in unexpected pure exponential growth in science production around the world. Increased competition, as well as boundary-spanning collaborations, drive unprecedented scientific advancement and technological innovation. In a book entitled The Century of Science: The Global Triumph of the Research University, we explore global scientific developments from the early 20th century to today. University-based research, especially, has risen globally to become the driving force of science production in STEM+ fields. Universities, with their multiple missions of research, teaching, and public service, are uniquely positioned to contribute to scientific output while simultaneously producing the next generation of scientists. [less ▲]

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See detailWhen Time Breaks: The Hiatus of Refugee Status
Van Der Walt, Johan Willem Gous UL

E-print/Working paper (2018)

“In the first place, we don’t like to be called ‘refugees.’ We ourselves call one another ‘newcomers’ or ‘immigrants.’” Already here, in the first sentence of Arendt’s essay “We Refugees,” does the hiatus ... [more ▼]

“In the first place, we don’t like to be called ‘refugees.’ We ourselves call one another ‘newcomers’ or ‘immigrants.’” Already here, in the first sentence of Arendt’s essay “We Refugees,” does the hiatus of refugee status become manifest. A divide already opens up between different habits of reference. Refugees refer to themselves in one way, non-refugees refer to them in another, and so does the projected or desired possibility of one world in which both refugees and non-refugees might find accommodation, split into two very different realities. Consciousness of the split is of course solely that of the refugees, at first. Initially, the hiatus is theirs only. Others – non-refugees – remain soundly oblivious to this fundamental split until such time as it brutally breaks into their world too, for instance, when the corpse of a four-year old child washes up on a beach, and washes up on every doorstep in a succession of media waves. And then the hiatus is suddenly everywhere and no one remains exempted. As the last sentence of Arendt’s essay contends forcefully, the split begins with the refugee status of some, but it ends with the bigger split of a world that begins to falter and fall apart: “The comity of European peoples went to pieces when, and because, it allowed its weakest member to be excluded and persecuted.” The comity of European peoples show all signs of going to pieces again today. When the comity of peoples goes to pieces, it is not only common space that cracks up, but also common time, the common time that warrants common space according to Kant’s Schematismuslehre. It is ultimately this breaking of time – the hiatus of time – that Arendt thematises elsewhere with reference to “the desolate aimless wanderings of Israeli tribes in the wilderness and the dangers which befell Aeneas before he reached the Italian shore.” “[T]his hiatus,” she continues, obviously creeps into all time speculations which deviate from the currently accepted notion of time as a continuous flow.” (Arendt On Revolution, 205). This text is also a supplementary discussion of my reviews of two recent monographs on Arendt. See: RECENT ARENDT SCHOLARSHIP: Review of The Wandering Thought of Hannah Arendt by Hans Jörg Sigwart, Palgrave MacMillan, 2016, ISBN: 978-1-137-48214-3, 147 pages (abbreviated as WT below), and Rightlessness in an Age of Rights. Hannah Arendt and the Contemporary Struggles of Migrants by Ayten Gündoğdu, New York: Oxford University Press: 2015, 298 pages, forthcoming in Constellations. [less ▲]

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See detailDelaunay Triangulations of Points on Circles
despré, vincent; devillers, olivier; Parlier, Hugo UL et al

E-print/Working paper (2018)

Delaunay triangulations of a point set in the Euclidean plane are ubiquitous in a number of computational sciences, including computational geometry. Delaunay triangulations are not well defined as soon ... [more ▼]

Delaunay triangulations of a point set in the Euclidean plane are ubiquitous in a number of computational sciences, including computational geometry. Delaunay triangulations are not well defined as soon as 4 or more points are concyclic but since it is not a generic situation, this difficulty is usually handled by using a (symbolic or explicit) perturbation. As an alternative, we propose to define a canonical triangulation for a set of concyclic points by using a max-min angle characterization of Delaunay triangulations. This point of view leads to a well defined and unique triangulation as long as there are no symmetric quadruples of points. This unique triangulation can be computed in quasi-linear time by a very simple algorithm. [less ▲]

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See detailConnecting Personal Data of Third Country Nationals: Interoperability of EU Databases in the Light of the CJEU's Case Law on Data Retention
Quintel, Teresa Alegra UL

E-print/Working paper (2018)

On 12 December 2017, the EU Commission presented a proposal on the interoperability of EU large-scale Information Systems. The proposal seeks to enable all centralised EU databases for security, border ... [more ▼]

On 12 December 2017, the EU Commission presented a proposal on the interoperability of EU large-scale Information Systems. The proposal seeks to enable all centralised EU databases for security, border and migration management to be interconnected by 2020. The underlying IT systems retain data of Third Country Nationals (TCNs), namely travellers, applicants for international protection, information relating to visa applications or data on missing persons and criminals. With the proposal, the Commission seeks to create new possibilities to exchange information, manage migration challenges and to enhance the Union’s internal security. The interconnectivity of databases would introduce fundamental changes to the current structure of EU IT-systems and requires careful consideration and assessment of compliance with EU data protection standards. This also means that access to information in an interoperable system must be strictly aligned to the access rights of the underlying databases and that requesting authorities only obtain the data that they are authorized to access. With interoperability, data once held in silos would be retained in three new centralized databases and would be more easily accessible, also for the prevention, investigation and prosecution of crime. Where criminal investigations previously required multiple searches in separate databases, this cascading safeguard shall progressively be abandoned to streamline access to personal data by law enforcement authorities. Despite simplified access conditions, this would require new types of processing operations for which the interoperability proposal does not provide a legal basis. During recent years, several judgments of the Court of Justice of the European Union (CJEU) have highlighted the difficulty of striking a proper balance between the fundamental rights to privacy and data protection, enshrined in Article 7 and 8 of the Charter of Fundamental Rights of the European Union (EU Charter) with an increased demand for security and the surveillance of potential criminals. The Court repeatedly pointed out the need to strike a fair balance between these (allegedly) competing interests and emphasised that law enforcement authorities should not be granted access to personal data without prior authorization. Using the CJEU’s judgments as vehicle and considering the assumption that TCNs risk to become subject to data retention measures in a disproportionate manner, the following analysis seeks to assess both existing EU databases and their foreseen interoperability against the requirements established by the Court in order to evaluate their (in)-compatibility with the fundamental rights standards enshrined in the EU Charter. [less ▲]

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See detailBayesian variable selection in linear dynamical systems
Aalto, Atte UL; Goncalves, Jorge UL

E-print/Working paper (2018)

We develop a method for reconstructing regulatory interconnection networks between variables evolving according to a linear dynamical system. The work is motivated by the problem of gene regulatory ... [more ▼]

We develop a method for reconstructing regulatory interconnection networks between variables evolving according to a linear dynamical system. The work is motivated by the problem of gene regulatory network inference, that is, finding causal effects between genes from gene expression time series data. In biological applications, the typical problem is that the sampling frequency is low, and consequentially the system identification problem is ill-posed. The low sampling frequency also makes it impossible to estimate derivatives directly from the data. We take a Bayesian approach to the problem, as it offers a natural way to incorporate prior information to deal with the ill-posedness, through the introduction of sparsity promoting prior for the underlying dynamics matrix. It also provides a framework for modelling both the process and measurement noises. We develop Markov Chain Monte Carlo samplers for the discrete-valued zero-structure of the dynamics matrix, and for the continuous-time trajectory of the system. [less ▲]

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See detailFrom Clustering Supersequences to Entropy Minimizing Subsequences for Single and Double Deletions
Atashpendar, Arash UL; Beunardeau, Marc; Connolly, Aisling et al

E-print/Working paper (2018)

A binary string transmitted via a memoryless i.i.d. deletion channel is received as a subsequence of the original input. From this, one obtains a posterior distribution on the channel input, corresponding ... [more ▼]

A binary string transmitted via a memoryless i.i.d. deletion channel is received as a subsequence of the original input. From this, one obtains a posterior distribution on the channel input, corresponding to a set of candidate supersequences weighted by the number of times the received subsequence can be embedded in them. In a previous work it is conjectured on the basis of experimental data that the entropy of the posterior is minimized and maximized by the constant and the alternating strings, respectively. In this work, we present an algorithm for counting the number of subsequence embeddings using a run-length encoding of strings. We then describe two different ways of clustering the space of supersequences and prove that their cardinality depends only on the length of the received subsequence and its Hamming weight, but not its exact form. Then, we consider supersequences that contain a single embedding of a fixed subsequence, referred to as singletons, and provide a closed form expression for enumerating them using the same run-length encoding. We prove an analogous result for the minimization and maximization of the number of singletons, by the alternating and the uniform strings, respectively. Next, we prove the original minimal entropy conjecture for the special cases of single and double deletions using similar clustering techniques and the same run-length encoding, which allow us to characterize the distribution of the number of subsequence embeddings in the space of compatible supersequences to demonstrate the effect of an entropy decreasing operation. [less ▲]

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See detailExpediting in Two-Echelon Spare Parts Inventory Systems
Drent, Melvin UL; Arts, Joachim UL

E-print/Working paper (2018)

We consider a two-echelon spare parts inventory system consisting of one central warehouse and multiple local warehouses. Each warehouse keeps multiple types of repairable parts to maintain several types ... [more ▼]

We consider a two-echelon spare parts inventory system consisting of one central warehouse and multiple local warehouses. Each warehouse keeps multiple types of repairable parts to maintain several types of capital goods. The local warehouses face Poisson demand and are replenished by the central warehouse. We assume that unsatisfied demand is backordered at all warehouses. Furthermore, we assume deterministic lead times for the replenishments of the local warehouses. The repair shop at the central warehouse has two repair options for each repairable part: a regular repair option and an expedited repair option. Both repair options have stochastic lead times. Irrespective of the repair option, each repairable part uses a certain resource for its repair. Assuming a dual-index policy at the central warehouse and base stock control at the local warehouses, an exact and efficient evaluation procedure for a given control policy is formulated. To find an optimal control policy, we look at the minimization of total investment costs under constraints on both the aggregate mean number of backorders per capital good type and the aggregate mean fraction of repairs that are expedited per repair resource. For this non-linear non-convex integer programming problem, we develop a greedy heuristic and an algorithm based on decomposition and column generation. Both solution approaches perform very well with average optimality gaps of 1.56 and 0.23 percent, respectively, across a large test bed of industrial size. [less ▲]

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See detailRisk and Refugee Migration
Joxhe, Majlinda UL; Bocqueho, Geraldine; Helstroffer, Jenny et al

E-print/Working paper (2018)

This paper uses the experimental setup of Tanaka et al. (2010) to measure refugees’ risk preferences. A sample of 206 asylum seekers was interviewed in 2017-18 in Luxembourg. Contrary to studies which ... [more ▼]

This paper uses the experimental setup of Tanaka et al. (2010) to measure refugees’ risk preferences. A sample of 206 asylum seekers was interviewed in 2017-18 in Luxembourg. Contrary to studies which focus on risk aversion in general, we analyze its components using a cumulative prospect theory (CPT) framework. We show that refugees exhibit particularly low levels of risk aversion compared to other populations and that CPT provides a better fit for modelling risk attitudes. Moreover, we include randomised temporary treatments provoking emotions and find a small significant impact on probability distortion. Robustness of the Tanaka et al. (2010) experimental framework is confirmed by including treatments regarding the embedding effect. Finally, we propose a theoretical model of refugee migration that integrates the insights from our experimental outcomes regarding the functional form of refugees’ decision under risk and the estimated parameter values. The model is then simulated using the data from our study. [less ▲]

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See detailEnergy efficiency optimization in MIMO interference channels: A successive pseudoconvex approximation approach
Yang, Yang UL; Pesavento, Marius; Chatzinotas, Symeon UL et al

E-print/Working paper (2018)

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See detailThe Credit Structure Database
Leon, Florian UL

E-print/Working paper (2018)

We describe a new publicly available dataset on credit structure across the world over the period 1995-2014. The database contains two modules. The first part reports the structure of bank loan by types ... [more ▼]

We describe a new publicly available dataset on credit structure across the world over the period 1995-2014. The database contains two modules. The first part reports the structure of bank loan by types of borrowers (households vs. firms). Data are available for 143 countries. Household credit is breakdown between mortgage loans and other household loans (credit cards, car loans, student loans, etc.). Firm credit is decomposed into six sectors (agriculture, industry, construction, transport, trade and other services). The second module contains credit by maturity for 85 countries. Short-term credit is defined as loans with a maturity of one year or less and long-term credit as loans whose maturity exceeds one year. Database is freely available and downlable in Excel and Stata format at the following link: https://sites.google.com/site/florianleon/research/data [less ▲]

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See detailLimit theorems for symmetric U-statistics using contractions
Döbler, Christian UL; Peccati, Giovanni UL

E-print/Working paper (2018)

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See detailDigitalisierung der Arbeit in Luxemburg - Teil 3
Sischka, Philipp UL; Steffgen, Georges UL

E-print/Working paper (2018)

Arbeitnehmer unterscheiden sich hinsichtlich dem Grad durch den ihre Arbeit von der Digitalisierung betroffen ist sowie durch die Auswirkungen, die die Digitalisierung auf ihre Arbeit und ihr Arbeits(er ... [more ▼]

Arbeitnehmer unterscheiden sich hinsichtlich dem Grad durch den ihre Arbeit von der Digitalisierung betroffen ist sowie durch die Auswirkungen, die die Digitalisierung auf ihre Arbeit und ihr Arbeits(er)leben haben. Arbeitnehmer, deren Arbeit stärker durch die Digitalisierung beeinflusst ist, erleben tendenziell mehr Partizipation, Feedback und Autonomie auf ihrer Arbeit. Gleichzeitig weisen sie auch mehr emotionale und mentale Anforderungen, sowie mehr Zeitdruck auf. Arbeitnehmer, deren Arbeit nur in geringem Maß von der Digitalisierung betroffen ist, sind dagegen weniger von emotionalen und mentalen Anforderungen, sowie von Zeitdruck, Konkurrenz und Mobbing betroffen. Insbesondere die geringere Planbarkeit von Arbeitszeit und Freizeit sowie die stärkere Überwachung und Kontrolle der Arbeitsleistung sind negative Konsequenzen der Digitalisierung, die zu einem verstärkten Erleben von emotionalen und mentalen Anforderungen sowie von Zeitdruck, Konkurrenz und Mobbing führt. Die Möglichkeit durch die Digitalisierung auch von zuhause oder von unterwegs arbeiten zu können führt einerseits zu mehr wahrgenommener Autonomie, andererseits ist dieses Potenzial der Digitalisierung auch mit negativen Konsequenzen verknüpft (z.B. erhöhter Zeitdruck). [less ▲]

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See detailDigitalisierung der Arbeit in Luxemburg - Teil 2
Sischka, Philipp UL; Steffgen, Georges UL

E-print/Working paper (2018)

Arbeitnehmer mit höherer formaler Bildung sowie Arbeitnehmer, die als Manager und Führungskräfte, in akademischen Berufen, als Techniker und als Bürokräfte arbeiten, berichten eher von einer gestiegenen ... [more ▼]

Arbeitnehmer mit höherer formaler Bildung sowie Arbeitnehmer, die als Manager und Führungskräfte, in akademischen Berufen, als Techniker und als Bürokräfte arbeiten, berichten eher von einer gestiegenen Entscheidungsfreiheit, von geringerer körperlicher Belastung, von mehr Aufgaben, von der Notwendigkeit ständiger Weiterentwicklung der eigenen Fähigkeiten sowie einer erhöhten Arbeitsleistung durch die Digitalisierung. Insbesondere Hilfsarbeitskräfte geben seltener an sowohl von den Vorteilen aus auch von den Nachteilen der Digitalisierung betroffen zu sein. Differenziert nach Geschlecht oder nach Alter ergeben sich oft nur geringfügige Unterschiede. [less ▲]

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See detailBisymmetric and quasitrivial operations: characterizations and enumerations
Devillet, Jimmy UL

E-print/Working paper (2018)

We investigate the class of bisymmetric and quasitrivial binary operations on a given set X and provide various characterizations of this class as well as the subclass of bisymmetric, quasitrivial, and ... [more ▼]

We investigate the class of bisymmetric and quasitrivial binary operations on a given set X and provide various characterizations of this class as well as the subclass of bisymmetric, quasitrivial, and order-preserving binary operations. We also determine explicitly the sizes of these classes when the set X is finite. [less ▲]

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See detailDigitalisierung der Arbeit in Luxemburg - Teil 1
Sischka, Philipp UL; Steffgen, Georges UL

E-print/Working paper (2018)

Die Digitalisierung steht derzeit im Fokus der öffentlichen und politischen Debatte. Im Folgenden wird dargestellt, wie Arbeitnehmer in Luxemburg ihre Arbeit durch die Digitalisierung beeinflusst sehen ... [more ▼]

Die Digitalisierung steht derzeit im Fokus der öffentlichen und politischen Debatte. Im Folgenden wird dargestellt, wie Arbeitnehmer in Luxemburg ihre Arbeit durch die Digitalisierung beeinflusst sehen. Hierbei werden die verschiedenen Formen der Digitalisierung sowie die Angst durch den technischen Fortschritt seinen Arbeitsplatz zu verlieren näher beleuchtet. Manager und Führungskräfte, Arbeitnehmer in akademischen Berufen, Techniker sowie Bürokräfte konstatieren einen starken Einfluss der Digitalisierung auf ihre Arbeit. Diese Einschätzung fällt für Arbeitnehmer in Dienstleistungs- und in Handwerksberufen sowie für Bedienern von Anlagen und Hilfsarbeitskräfte moderater aus. Während Manager und Führungskräfte, sowie Arbeitnehmer in akademischen Berufen vor allem die Bedeutung von elektronischer Kommunikation und unterstützender elektronischer Geräte hervorheben, kommt für Techniker und Arbeitnehmer in Handwerksberufen auch noch das Arbeiten mit computergesteuerten Maschinen oder Robotern hinzu. Die mit der Digitalisierung und dem technischen Fortschritt häufig debattierte Angst vor Arbeitsplatzverlust ist insgesamt moderat ausgeprägt. Etwas stärker ist diese bei Arbeitnehmern der Altersgruppe ab 35 Jahren sowie bei Bedienern von Anlagen und Bürokräften ausgeprägt. [less ▲]

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See detailAttacks and Countermeasures for White-box Designs
Biryukov, Alex UL; Udovenko, Aleksei UL

E-print/Working paper (2018)

In the traditional symmetric cryptography, the adversary has access only to the inputs and outputs of a cryptographic primitive. In the white-box model the adversary is given full access to the ... [more ▼]

In the traditional symmetric cryptography, the adversary has access only to the inputs and outputs of a cryptographic primitive. In the white-box model the adversary is given full access to the implementation. He can use both static and dynamic analysis as well as fault analysis in order to break the cryptosystem, e.g. to extract embedded secret key. Implementations secure in such model have many applications in industry. However, creating such implementations turns out to be a very challenging if not an impossible task. Recently, Bos et al. proposed a generic attack on white-box primitives called differential computation analysis (DCA). This attack applies to most existent white-box implementations both from academia and industry. The attack comes from side-channel cryptanalysis method. The most common method protecting against such side-channel attacks is masking. Therefore, masking can be used in white-box implementations to protect against the DCA attack. In this paper we investigate this possibility and present multiple generic attacks against masked white-box implementations. We use the term “masking” in a very broad sense. As a result, we deduce new constraints that any secure white-box implementation must satisfy. We suggest partial countermeasures against the attacks. Some of our attacks were successfully applied to the WhibOx 2017 challenges. [less ▲]

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See detailBrexit Seen from Luxembourg
Högenauer, Anna-Lena UL

E-print/Working paper (2018)

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See detailDemographics and FDI: Lessons from China's One-Child Policy
Donaldson, John B.; Koulovatianos, Christos UL; Li, Jian et al

E-print/Working paper (2018)

Lucas (1990) argues that the neoclassical adjustment process fails to explain the relative paucity of FDI inflows from rich to poor countries. In this paper we consider a natural experiment: using China ... [more ▼]

Lucas (1990) argues that the neoclassical adjustment process fails to explain the relative paucity of FDI inflows from rich to poor countries. In this paper we consider a natural experiment: using China as the treated country and India as the control, we show that the dynamics of the relative FDI flows subsequent to the implementation of China's one-child policy, as seen in the data, are consistent with neoclassical fundamentals. In particular, following the introduction of the one-child policy in China, the capital-labor (K/L) ratio of China increased relative to that of India, and, simultaneously, relative FDI inflows into China vs. India declined. These observations are explained in the context of a simple neoclassical OLG paradigm. The adjustment mechanism works as follows: the reduction in the (urban) labor force due to the one-child policy increases the savings per capita. This increases the K/L ratio and reduces the marginal product of capital (MPK). The reduction in MPK (relative to India) reduces the relative attractiveness of investment in China and is thus associated with lower FDI/GDP ratios. Our paper contributes to the nascent literature exploring demographic transitions and their effects on FDI flows. [less ▲]

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See detailDo banks and microfinance institutions compete? Microevidence from Madagascar
Leon, Florian UL; Baraton, Pierrick

E-print/Working paper (2018)

In recent years, both microfinance institutions (MFIs) and banks across the world have been converging towards the financing of small enterprises with high financing needs. This paper scrutinizes whether ... [more ▼]

In recent years, both microfinance institutions (MFIs) and banks across the world have been converging towards the financing of small enterprises with high financing needs. This paper scrutinizes whether banks and MFIs compete each other as a result of recent transformations in both industries. In doing so, we study whether the loan strategy of a microfinance institution is shaped by the local presence of a bank. Specifically, we investigate whether bank proximity influences loan conditions provided by one of the largest microfinance institutions in Madagascar. We employ an original panel dataset of 32,374 loans granted to 14,834 borrowers over the period 2008-2014. We find that the closer a bank is located to a given MFI borrower, the larger the loan obtained and the less collateral required. These results are insensitive to several robustness tests for possible endogeneity of distance, sample selection issue, and alternative specifications. In addition, findings are stronger for larger and more established (older) firms in line with our hypothesis. [less ▲]

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Peer Reviewed
See detailFragebogen HBSC 2018 (enseignement fondamental)
Heinz, Andreas UL

E-print/Working paper (2018)

Detailed reference viewed: 61 (9 UL)
Peer Reviewed
See detailFragebogen HBSC 2018 (enseignement secondaire)
Heinz, Andreas UL

E-print/Working paper (2018)

Detailed reference viewed: 32 (3 UL)
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Peer Reviewed
See detailAlonso and the scaling of urban profiles
Delloye, Justin; Lemoy, Rémi UL; Caruso, Geoffrey UL

E-print/Working paper (2018)

Urban characteristics scaling with total population has become an important urban research field since one needs to better understand the benefits and disadvantages of urban growth and fur- ther ... [more ▼]

Urban characteristics scaling with total population has become an important urban research field since one needs to better understand the benefits and disadvantages of urban growth and fur- ther population concentration. Urban scaling research, however, is largely disconnected from the empirics and theory of intra-urban structure for it considers averaged attributes and ignores resi- dential choice trade-offs between transport and housing costs within cities. Using this fundamental trade-off, the monocentric model of Alonso provides theory to urban density profiles. However, it is silent about how these profiles scale with population, thus preventing empirical scaling studies to anchor in a strong micro-economic theory. This paper fixes this gap by introducing power laws for land and for population density in the Alonso model. From an augmented model with land use, we derive the conditions at which equilibrium profiles match recent empirical findings about the scaling of urban land and population density profiles in European cities. We find that the Alonso model is theoretically compatible with the observed scaling of population density profiles and leads to a satisfactory representation of European cities. The conditions for this compatibility refine current understanding of wage and transport costs elasticities with population. Although they require a scaling power of the profile of the share of urbanised land that is different from what is observed, it is argued that alternatives specifications of transport cost functions could solve this issue. Thus our results call for revisiting theories about land development and housing processes as well as the empirics of agglomeration benefits and transport costs. [less ▲]

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See detailLong-term finance and entrepreneurship
Leon, Florian UL

E-print/Working paper (2018)

This paper investigates whether long-term finance affects the firm entry across the world. We construct a new database on short-term and long-term credit provided by commercial banks to the private sector ... [more ▼]

This paper investigates whether long-term finance affects the firm entry across the world. We construct a new database on short-term and long-term credit provided by commercial banks to the private sector in 85 countries over the period 1995-2014. We then analyze whether differences in entrepreneurship are correlated with the provision of short-term and long-term bank credit. Data on entrepreneurship are extracted from two frequently used databases: the Global Entrepreneurship Monitoring dataset and Entrepreneurship Database, each of which captures different aspects of firm creation. Econometric results indicate that long-term credit does not stimulate the firm entry. On the contrary, we find that short-term credit exerts a positive impact at each stage of firm creation from activity birth to registration. Our findings are robust to a battery of sensitivity tests, including additional control variables, alternative dependent variables, alternative sample, and changes in econometric specification. Our findings suggest that better provision of short-term credit allows entrepreneurs to apply for a formal loan instead of relying exclusively on informal loans or internal funds, contrary to long-term loans [less ▲]

Detailed reference viewed: 27 (7 UL)
See detailLa réponse au défi migratoire : «Europe souveraine» ou «souverainisme de repli» ?
Gatti, Mauro UL

E-print/Working paper (2018)

La migration est probablement le « défi majeur » de l’Europe, aujourd’hui et dans les années qui viennent, comme le reconnaît Emmanuel Macron dans son discours de la Sorbonne de septembre 2017. On peut ... [more ▼]

La migration est probablement le « défi majeur » de l’Europe, aujourd’hui et dans les années qui viennent, comme le reconnaît Emmanuel Macron dans son discours de la Sorbonne de septembre 2017. On peut noter, par ailleurs, que la gestion de ce défi est à présent inadéquate : si 285.000 migrants ont été sauvés par des opérations coordonnées par l’Union européenne, 3.139 sont morts en 2017 ; en outre, l’état des droits des migrants dans l’Union et, surtout, dans les pays partenaires, reste problématique. Le « souverainisme de repli » n’assure aucune solution : « l’Europe seule peut, en un mot, assurer une souveraineté réelle » (Macron). Et la souveraineté de l’Europe – conçue comme la « capacité à exister dans le monde actuel pour y défendre nos valeurs et nos intérêts » – ne peut que s’assurer par la « solidarité » entre les Etats membres. Emmanuel Macron propose deux solutions au défi de la migration, qui paraissent toutefois insuffisantes ou illusoires : la création d’un « espace commun des frontières » vis-à- vis de l’extérieur et une gestion plus efficace de l’asile à l’intérieur de l’Union. [less ▲]

Detailed reference viewed: 50 (7 UL)
See detailContinuous time Gaussian process dynamical models in gene regulatory network inference
Aalto, Atte UL; Viitasaari, Lauri; Ilmonen, Pauliina et al

E-print/Working paper (2018)

One of the focus areas of modern scientific research is to reveal mysteries related to genes and their interactions. The dynamic interactions between genes can be encoded into a gene regulatory network ... [more ▼]

One of the focus areas of modern scientific research is to reveal mysteries related to genes and their interactions. The dynamic interactions between genes can be encoded into a gene regulatory network (GRN), which can be used to gain understanding on the genetic mechanisms behind observable phenotypes. GRN inference from time series data has recently been a focus area of systems biology. Due to low sampling frequency of the data, this is a notoriously difficult problem. We tackle the challenge by introducing the so-called continuous-time Gaussian process dynamical model (GPDM), based on Gaussian process framework that has gained popularity in nonlinear regression problems arising in machine learning. The model dynamics are governed by a stochastic differential equation, where the dynamics function is modelled as a Gaussian process. We prove the existence and uniqueness of solutions of the stochastic differential equation. We derive the probability distribution for the Euler discretised trajectories and establish the convergence of the discretisation. We develop a GRN inference method based on the developed framework. The method is based on MCMC sampling of trajectories of the GPDM and estimating the hyperparameters of the covariance function of the Gaussian process. Using benchmark data examples, we show that our method is computationally feasible and superior in dealing with poor time resolution. [less ▲]

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See detailKummer theory for number fields
Perucca, Antonella UL; Sgobba, Pietro

E-print/Working paper (2018)

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See detailBig Moves of Mutual Funds
Lehnert, Thorsten UL

E-print/Working paper (2018)

Detailed reference viewed: 23 (1 UL)
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See detailMath around the Clock
Perucca, Antonella UL

E-print/Working paper (2018)

We present several original arithmetical clocks presenting the numbers from 1 to 12 according to some specific theme (e.g. use only the digit 7).

Detailed reference viewed: 40 (6 UL)
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See detailProducts in the category of Z_2^n manifolds
Bruce, Andrew UL; Poncin, Norbert UL

E-print/Working paper (2018)

Detailed reference viewed: 26 (1 UL)
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Peer Reviewed
See detailA parallel dual-grid multiscale approach to CFD-DEM couplings
Pozzetti, Gabriele UL; Jasak, Hrvoje; Besseron, Xavier UL et al

E-print/Working paper (2018)

In this work, a new parallel dual-grid multiscale approach for CFD-DEM couplings is investigated. Dual- grid multiscale CFD-DEM couplings have been recently developed and successfully adopted in different ... [more ▼]

In this work, a new parallel dual-grid multiscale approach for CFD-DEM couplings is investigated. Dual- grid multiscale CFD-DEM couplings have been recently developed and successfully adopted in different applications still, an efficient parallelization for such a numerical method represents an open issue. Despite its ability to provide grid convergent solutions and more accurate results than standard CFD-DEM couplings, this young numerical method requires good parallel performances in order to be applied to large-scale problems and, therefore, extend its range of application. The parallelization strategy here proposed aims to take advantage of the enhanced complexity of a dual-grid coupling to gain more flexibility in the domain partitioning while keeping a low inter-process communication cost. In particular, it allows avoiding inter- process communication between CFD and DEM software and still allows adopting complex partitioning strategies thanks to an optimized grid-based communication. It is shown how the parallelized multiscale coupling holds all its natural advantages over a mono-scale coupling and can also have better parallel performance. Three benchmark cases are presented to assess the accuracy and performance of the strategy. It is shown how the proposed method allows maintaining good parallel performance when operated over 1000 processes. [less ▲]

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See detailFinancial ratios analysis in determination of bank performance in the German banking sector
Lardic, Sandrine; Terraza, Virginie UL

E-print/Working paper (2018)

Detailed reference viewed: 14 (2 UL)
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See detailOn the Hilbert eigenvariety at exotic and CM classical weight 1 points
Deo, Shaunak UL; Betina, Adel; Fite, Francesc

E-print/Working paper (2018)

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See detailDihedral Universal Deformations
Deo, Shaunak UL; Wiese, Gabor UL

E-print/Working paper (2018)

This article deals with universal deformations of dihedral representations with a particular focus on the question when the universal deformation is dihedral. Results are obtained in three settings: (1 ... [more ▼]

This article deals with universal deformations of dihedral representations with a particular focus on the question when the universal deformation is dihedral. Results are obtained in three settings: (1) representation theory, (2) algebraic number theory, (3) modularity. As to (1), we prove that the universal deformation is dihedral if all infinitesimal deformations are dihedral. Concerning (2) in the setting of Galois representations of number fields, we give sufficient conditions to ensure that the universal deformation relatively unramified outside a finite set of primes is dihedral, and discuss in how far these conditions are necessary. As a side-result, we obtain cases of the unramified Fontaine-Mazur conjecture. As to (3), we prove a modularity theorem of the form `R=T' for parallel weight one Hilbert modular forms for cases when the minimal universal deformation is dihedral. [less ▲]

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See detailLocal curvature estimates for the Laplacian flow
Li, Yi UL

E-print/Working paper (2018)

Detailed reference viewed: 50 (7 UL)
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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)

Detailed reference viewed: 21 (0 UL)
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See detailA hyper-reduction method using adaptivity to cut the assembly costs of reduced order models
Hale, Jack UL; Schenone, Elisa; Baroli, Davide UL et al

E-print/Working paper (2018)

At every iteration or timestep of the online phase of some reduced-order modelling schemes, large linear systems must be assembled and then projected onto a reduced order basis of small dimension. The ... [more ▼]

At every iteration or timestep of the online phase of some reduced-order modelling schemes, large linear systems must be assembled and then projected onto a reduced order basis of small dimension. The projected small linear systems are cheap to solve, but assembly and projection are now the dominant computational cost. In this paper we introduce a new hyper-reduction strategy called reduced assembly (RA) that drastically cuts these costs. RA consists of a triangulation adaptation algorithm that uses a local error indicator to con- struct a reduced assembly triangulation specially suited to the reduced order basis. Crucially, this reduced assembly triangulation has fewer cells than the original one, resulting in lower assembly and projection costs. We demonstrate the efficacy of RA on a Galerkin-POD type reduced order model (RAPOD). We show performance increases of up to five times over the baseline Galerkin-POD method on a non-linear reaction-diffusion problem solved with a semi-implicit time-stepping scheme and up to seven times for a 3D hyperelasticity problem solved with a continuation Newton-Raphson algorithm. The examples are implemented in the DOLFIN finite element solver using PETSc and SLEPc for linear algebra. Full code and data files to produce the results in this paper are provided as supplementary material. [less ▲]

Detailed reference viewed: 21 (5 UL)
See detailAccounting for Differences in Income Inequality across Countries: Ireland and the United Kingdom
Sologon, Denisa M.; van Kerm, Philippe UL; Li, Jinjing et al

E-print/Working paper (2018)

This paper proposes a framework for studying international differences in the distribution of household income. Integrating micro-econometric and micro-simulation approaches in a decomposition analysis it ... [more ▼]

This paper proposes a framework for studying international differences in the distribution of household income. Integrating micro-econometric and micro-simulation approaches in a decomposition analysis it quantifies the role of tax-benefit systems, employment and occupational structures, labour prices and market returns, and demographic composition in accounting for differences in income inequality across countries. Building upon EUROMOD (the European tax-benefit calculator) and its harmonized datasets, the model is portable and can be implemented for any cross-country comparisons within the EU. An application to the UK and Ireland--two countries that have much in common while displaying different levels of inequality--shows that differences in tax-benefit rules between the two countries account for roughly half of the observed difference in disposable household income inequality. Demographic differences play negligible roles. The Irish tax-benefit system is more redistributive than UK's due to a higher tax progressivity and higher average transfer rates. These are largely attributable to policy parameter differences, but also to differences in pre-tax, pre-transfer income distributions. [less ▲]

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See detailEffect of increasing the ramification on pseudo-deformation rings
Deo, Shaunak UL

E-print/Working paper (2018)

Detailed reference viewed: 18 (0 UL)
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See detailFunctional analytic issues in Z_2 ^n Geometry
Bruce, Andrew UL; Poncin, Norbert UL

E-print/Working paper (2018)

Detailed reference viewed: 17 (1 UL)
See detailEntwicklungen der Trans*-Bewegung in der Bundesrepublik Deutschland
De Silva, Adrian UL

E-print/Working paper (2018)

Detailed reference viewed: 58 (18 UL)
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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 detailMutant Quality Indicators
Papadakis, Mike UL; Titcheu Chekam, Thierry UL; Le Traon, Yves UL

E-print/Working paper (2018)

Detailed reference viewed: 121 (9 UL)
See detailCharacterization of field homomorphisms through Pexiderized functional equations
Gselmann, Eszter; Kiss, Gergely UL; Vincze, Csaba

E-print/Working paper (2018)

Detailed reference viewed: 12 (0 UL)
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See detailIsolation of nucleic acids from low biomass samples: detection and removal of sRNA contaminants
Heintz-Buschart, Anna; Yusuf, Dilmurat; Kaysen, Anne UL et al

E-print/Working paper (2017)

Sequencing-based analyses of low-biomass samples are known to be prone to misinterpretation due to the potential presence of contaminating molecules derived from laboratory reagents and environments. Due ... [more ▼]

Sequencing-based analyses of low-biomass samples are known to be prone to misinterpretation due to the potential presence of contaminating molecules derived from laboratory reagents and environments. Due to its inherent instability, contamination with RNA is usually considered to be unlikely. Here we report the presence of small RNA (sRNA) contaminants in widely used microRNA extraction kits and means for their depletion. Sequencing of sRNAs extracted from human plasma samples was performed and significant levels of non-human (exogenous) sequences were detected. The source of the most abundant of these sequences could be traced to the microRNA extraction columns by qPCR-based analysis of laboratory reagents. The presence of artefactual sequences originating from the confirmed contaminants were furthermore replicated in a range of published datasets. To avoid artefacts in future experiments, several protocols for the removal of the contaminants were elaborated, minimal amounts of starting material for artefact-free analyses were defined, and the reduction of contaminant levels for identification of bona fide sequences using 'ultra-clean' extraction kits was confirmed. In conclusion, this is the first report of the presence of RNA molecules as contaminants in laboratory reagents. The described protocols should be applied in the future to avoid confounding sRNA studies. [less ▲]

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Peer Reviewed
See detailFundamental limits to helical edge conductivity due to sphin-phonon scattering
Groenendijk, Solofo UL; Dolcetto; Schmidt, Thomas UL

E-print/Working paper (2017)

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Peer Reviewed
See detailUniversal scaling of quench-induced correlations in a one-dimensional channel at finite temperature
Calzona, Alessio UL; Gambetta, Filippo Maria; Carrega, Matteo et al

E-print/Working paper (2017)

Detailed reference viewed: 30 (0 UL)
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See detailDie allgemeine Lebenszufriedenheit von Schülern in Luxemburg
Kern, Matthias Robert UL; Residori, Caroline UL; Heinz, Andreas UL et al

E-print/Working paper (2017)

Detailed reference viewed: 53 (16 UL)
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See detailGesundheitsbeschwerden von Schülern in Luxemburg
Heinz, Andreas UL; Kern, Matthias Robert UL; Residori, Caroline UL et al

E-print/Working paper (2017)

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Peer Reviewed
See detailInternetdelikte und die Herausforderungen des Forum Shoppings
Schmitz, Sandra UL

E-print/Working paper (2017)

Detailed reference viewed: 24 (1 UL)
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See detailÜbergewicht bei Schülern in Luxemburg
Residori, Caroline UL; Kern, Matthias Robert UL; Heinz, Andreas UL et al

E-print/Working paper (2017)

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See detailL'ethnographie du travail
de Saint-Georges, Ingrid UL

E-print/Working paper (2017)

Detailed reference viewed: 24 (1 UL)
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See detailMechanizing Principia Logico-Metaphysica in Functional Type Theory
Kirchner, Daniel; Benzmüller, Christoph UL; Zalta, Edward N.

E-print/Working paper (2017)

Principia Logico-Metaphysica proposes a foundational logical theory for metaphysics, mathematics, and the sciences. It contains a canonical development of Abstract Object Theory [AOT], a metaphysical ... [more ▼]

Principia Logico-Metaphysica proposes a foundational logical theory for metaphysics, mathematics, and the sciences. It contains a canonical development of Abstract Object Theory [AOT], a metaphysical theory (inspired by ideas of Ernst Mally, formalized by Zalta) that differentiates between ordinary and abstract objects. This article reports on recent work in which AOT has been successfully represented and partly automated in the proof assistant system Isabelle/HOL. [less ▲]

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See detailTime Averages of Markov Processes and Applications to Two-Timescale Problems
Pepin, Bob UL

E-print/Working paper (2017)

Detailed reference viewed: 22 (0 UL)