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See detailThe mod 2 cohomology rings of congruence subgroups in the Bianchi groups
Berkove, Ethan; Lakeland, Grant; Rahm, Alexander UL

E-print/Working paper (in press)

We provide new tools for the calculation of the torsion in the cohomology of congruence subgroups in the Bianchi groups : An algorithm for finding particularly useful fundamental domains, and an analysis ... [more ▼]

We provide new tools for the calculation of the torsion in the cohomology of congruence subgroups in the Bianchi groups : An algorithm for finding particularly useful fundamental domains, and an analysis of the equivariant spectral sequence combined with torsion subcomplex reduction. [less ▲]

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See detailNo more Piecemeal Tactics
Kafteranis, Dimitrios UL; Robert, Brochhaus

E-print/Working paper (2021)

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See detailAssessing the role of polygenic background on the penetrance of monogenic forms in Parkinson\textquoterights disease. 2021.06.06.21253270
Hassanin, Emadeldin; May, Patrick UL; Aldisi, Rana et al

E-print/Working paper (2021)

Background: Several rare and common variants are associated with Parkinson's disease. However, there is still an incomplete penetrance in the carriers of rare variants associated with Parkinson's disease ... [more ▼]

Background: Several rare and common variants are associated with Parkinson's disease. However, there is still an incomplete penetrance in the carriers of rare variants associated with Parkinson's disease. To address this issue, we investigated whether a PRS calculated from significant GWAS SNPs affects the penetrance of Parkinson's disease among carriers of rare monogenic variants in known Parkinson's disease genes and those with a family history. Methods: We calculated the PRS based on common variants and selected the carriers of rare monogenic variants by using the exome data from UK Biobank. Individuals were divided into three risk categories based on PRS: low (<10%), intermediate (10%-90%), and high (>90%) risk groups. We then compared how PRS affects Parkinson\textquoterights disease risk among carriers of rare monogenic variants and those with family-history. Results: We observed a two-fold higher odds ratio for a carrier of a monogenic variant that had a high PRS (OR 4.07,95\% CI, 1.72-8.08) compared to carriers with a low PRS (OR 1.91, 95\% CI, 0.31-6.05). In the same line, carriers with a first-degree family history and with \>90\% PRS have even a higher risk of developing PD (OR 23.53, 95\%CI 5.39-71.54) compared to those with \<90\% PRS (OR 9.54, 95\% CI 3.32-21.65). Conclusions: Our results show that PRS, carrier status, and family history contribute independently and additively to the Parkinson's disease risk. [less ▲]

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See detailBreast and prostate cancer risk: the interplay of polygenic risk, high-impact monogenic variants, and family history 2021.06.04.21258277
Hassanin, Emadeldin; May, Patrick UL; Aldisi, Rana et al

E-print/Working paper (2021)

Purpose: Investigate to which extent polygenic risk scores (PRS), high-impact monogenic variants, and family history affect breast and prostate cancer risk by assessing cancer prevalence and cancer ... [more ▼]

Purpose: Investigate to which extent polygenic risk scores (PRS), high-impact monogenic variants, and family history affect breast and prostate cancer risk by assessing cancer prevalence and cancer cumulative lifetime incidence. Methods 200,643 individuals from the UK Biobank were stratified as follows: 1. carriers or non-carriers of high impact constitutive, monogenic variants in cancer susceptibility genes, 2. high or non-high PRS (90th percentile threshold), 3. with or without a family history of cancer. Multivariable logistic regression was used to compare the odds ratio (OR) across the different groups while Cox proportional hazards models were used to compute the cumulative incidence through life. Results Breast and prostate cancer cumulative incidence by age 70 is 7 and 5 for non-carriers with non-high PRS and reaches 37 and 32 among carriers of high-impact variants in cancer susceptibility genes with high PRS. The additional presence of family history is associated with a further increase of the risk of developing cancer reaching an OR of 14 and 21 for breast and prostate cancer, respectively. Conclusion: High PRS confers a cancer risk comparable to high-impact monogenic variants. Family history, monogenic variants, and PRS contribute additively to breast and prostate cancer risk. [less ▲]

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See detailHeterozygous variants in KCNC2 cause a broad spectrum of epilepsy phenotypes associated with characteristic functional alterations 2021.05.21.21257099
Schwarz, Niklas; Seiffert, Simone; Pendziwiat, Manuela et al

E-print/Working paper (2021)

Background KCNC2 encodes a member of the shaw-related voltage-gated potassium channel family (KV3.2), which are important for sustained high-frequency firing and optimized energy efficiency of action ... [more ▼]

Background KCNC2 encodes a member of the shaw-related voltage-gated potassium channel family (KV3.2), which are important for sustained high-frequency firing and optimized energy efficiency of action potentials in the brain.Methods Individuals with KCNC2 variants detected by exome sequencing were selected for clinical, further genetic and functional analysis. The cases were referred through clinical and research collaborations in our study. Four de novo variants were examined electrophysiologically in Xenopus laevis oocytes.Results We identified novel KCNC2 variants in 27 patients with various forms of epilepsy. Functional analysis demonstrated gain-of-function in severe and loss-of-function in milder phenotypes as the underlying pathomechanisms with specific response to valproic acid.Conclusion These findings implicate KCNC2 as a novel causative gene for epilepsy emphasizing the critical role of KV3.2 in the regulation of brain excitability with an interesting genotype-phenotype correlation and a potential concept for precision medicine. [less ▲]

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See detailAggregated hold-out for sparse linear regression with a robust loss function
Maillard, Guillaume UL

E-print/Working paper (2021)

Sparse linear regression methods generally have a free hyperparameter which controls the amount of sparsity, and is subject to a bias-variance tradeoff. This article considers the use of Aggregated hold ... [more ▼]

Sparse linear regression methods generally have a free hyperparameter which controls the amount of sparsity, and is subject to a bias-variance tradeoff. This article considers the use of Aggregated hold-out to aggregate over values of this hyperparameter, in the context of linear regression with the Huber loss function. Aggregated hold-out (Agghoo) is a procedure which averages estimators selected by hold-out (cross-validation with a single split). In the theoretical part of the article, it is proved that Agghoo satisfies a non-asymptotic oracle inequality when it is applied to sparse estimators which are parametrized by their zero-norm. In particular, this includes a variant of the Lasso introduced by Zou, Hastié and Tibshirani \cite{Zou_Has_Tib:2007}. Simulations are used to compare Agghoo with cross-validation. They show that Agghoo performs better than CV when the intrinsic dimension is high and when there are confounders correlated with the predictive covariates. [less ▲]

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See detailLoss of function variants in the KCNQ5 gene are associated with genetic generalized epilepsies
Krueger, Johanna; Schubert, Julian; Kegele, Josua et al

E-print/Working paper (2021)

Objective: De novo missense variants in KCNQ5, encoding the voltage gated K+ channel KV7.5, have been described as a cause of developmental and epileptic encephalopathy (DEE) or intellectual disability ... [more ▼]

Objective: De novo missense variants in KCNQ5, encoding the voltage gated K+ channel KV7.5, have been described as a cause of developmental and epileptic encephalopathy (DEE) or intellectual disability (ID). We set out to identify disease-related KCNQ5 variants in genetic generalized epilepsy (GGE) and their underlying mechanisms. Methods: 1292 families with GGE were studied by next-generation sequencing. Whole-cell patch-clamp recordings, biotinylation and phospholipid overlay assays were performed in mammalian cells combined with docking and homology modeling. Results: We identified three deleterious heterozygous missense variants, one truncation and one splice site alteration in five independent families with GGE with predominant absence seizures, two variants were also associated with mild to moderate ID. All three missense variants displayed a strongly decreased current density indicating a loss-of-function (LOF). When mutant channels were co-expressed with wild-type (WT) KV7.5 or KV7.5 and KV7.3 channels, three variants also revealed a significant dominant-negative effect on WT channels. Other gating parameters were unchanged. Biotinylation assays indicated a normal surface expression of the variants. The p.Arg359Cys variant altered PI(4,5)P2-interaction, presumably in the non-conducting preopen-closed state. Interpretation: Our study indicates that specific deleterious KCNQ5 variants are associated with GGE, partially combined with mild to moderate ID. The disease mechanism is a LOF partially with dominant-negative effects through functional, rather than trafficking deficits. LOF of KV7.5 channels will reduce the M-current, likely resulting in increased excitability of KV7.5-expressing neurons. Further studies on a network level are necessary to understand which circuits are affected and how the variants induce generalized seizures. [less ▲]

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See detailUltra-rare constrained missense variants in the epilepsies: Shared and specific enrichment patterns in neuronal gene-sets 2021.04.18.440264
Koko, Mahmoud; Krause, Roland UL; Sander, Thomas et al

E-print/Working paper (2021)

Background: Burden analysis in epilepsy has shown an excess of deleterious ultra-rare variants (URVs) in few gene-sets, such as known epilepsy genes, constrained genes, ion channel or GABAA receptor genes ... [more ▼]

Background: Burden analysis in epilepsy has shown an excess of deleterious ultra-rare variants (URVs) in few gene-sets, such as known epilepsy genes, constrained genes, ion channel or GABAA receptor genes. We set out to investigate the burden of URVs in a comprehensive range of gene-sets presumed to be implicated in epileptogenesis. Methods: We investigated several constraint and conservation-based strategies to study whole exome sequencing data from European individuals with developmental and epileptic encephalopathies (DEE, n = 1,003), genetic generalized epilepsy (GGE, n = 3,064), and non-acquired focal epilepsy (NAFE, n = 3,522), collected by the Epi25 Collaborative, compared to 3,962 ancestry-matched controls. The burden of 12 URVs types in 92 gene-sets was compared between epilepsy cases (DDE, GGE, NAFE) and controls using logistic regression analysis. Results: Burden analysis of brain-expressed genes revealed an excess of different URVs types in all three epilepsy categories which was largest for constrained missense variants. The URVs burden was prominent in neuron-specific, synaptic and developmental genes as well as genes encoding ion channels and receptors, and it was generally higher for DEE and GGE compared to NAFE. The patterns of URVs burden in gene-sets expressed in inhibitory vs. excitatory neurons or receptors suggested a high burden in both in DEE but a differential involvement of inhibitory genes in GGE, while excitatory genes were predominantly affected in NAFE. Top ranking susceptibility genes from a recent genome-wide association study (GWAS) of generalized and focal epilepsies displayed a higher URVs burden in constrained coding regions in GGE and NAFE, respectively. Conclusions: Using exome-based gene-set burden analysis, we demonstrate that missense URVs affecting mainly constrained sites are enriched in neuronal genes in both common and rare severe epilepsy syndromes. Our results indicate a differential impact of these URVs in genes expressed in inhibitory vs. excitatory neurons and receptors in generalized vs. focal epilepsies. The excess of URVs in top-ranking GWAS risk-genes suggests a convergence of rare deleterious and common risk-variants in the pathogenesis of generalized and focal epilepsies. [less ▲]

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See detailMalliavin calculus for marked binomial processes: portfolio optimisation in the trinomial model and compound Poisson approximation
Halconruy, Hélène UL

E-print/Working paper (2021)

In this paper we develop a stochastic analysis for marked binomial processes, that can be viewed as the discrete analogues of marked Poisson processes. The starting point is the statement of a chaotic ... [more ▼]

In this paper we develop a stochastic analysis for marked binomial processes, that can be viewed as the discrete analogues of marked Poisson processes. The starting point is the statement of a chaotic expansion for square-integrable (marked binomial) functionals, prior to the elaboration of a Markov-Malliavin structure within this framework. We take advantage of the new formalism to deal with two main applications. First, we revisit the Chen-Stein method for the (compound) Poisson approximation which we perform in the paradigm of the built Markov-Malliavin structure, before studying in the second one the problem of portfolio optimisation in the trinomial model. [less ▲]

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See detailGenotype-phenotype correlations in SCN8A-related disorders reveal prognostic and therapeutic implications
Johannesen, Katrine M.; Liu, Yuanyuan; Gjerulfsen, Cathrine E. et al

E-print/Working paper (2021)

We report detailed functional analyses and genotype-phenotype correlations in 433 individuals carrying disease-causing variants in SCN8A, encoding the voltage-gated Na+ channel NaV1.6. Five different ... [more ▼]

We report detailed functional analyses and genotype-phenotype correlations in 433 individuals carrying disease-causing variants in SCN8A, encoding the voltage-gated Na+ channel NaV1.6. Five different clinical subgroups could be identified: 1) Benign familial infantile epilepsy (BFIE) (n=17, normal cognition, treatable seizures), 2) intermediate epilepsy (n=36, mild ID, partially pharmacoresponsive), 3) developmental and epileptic encephalopathy (DEE, n=191, severe ID, majority pharmacoresistant), 4) generalized epilepsy (n=21, mild to moderate ID, frequently with absence seizures), and 5) affected individuals without epilepsy (n=25, mild to moderate ID). Groups 1-3 presented with early-onset (median: four months) focal or multifocal seizures and epileptic discharges, whereas the onset of seizures in group 4 was later (median: 39 months) with generalized epileptic discharges. The epilepsy was not classifiable in 143 individuals. We performed functional studies expressing missense variants in ND7/23 neuroblastoma cells and primary neuronal cultures using recombinant tetrodotoxin insensitive human NaV1.6 channels and whole-cell patch clamping. Two variants causing DEE showed a strong gain-of-function (GOF, hyperpolarising shift of steady-state activation, strongly increased neuronal firing rate), and one variant causing BFIE or intermediate epilepsy showed a mild GOF (defective fast inactivation, less increased firing). In contrast, all three variants causing generalized epilepsy induced a loss-of-function (LOF, reduced current amplitudes, depolarising shift of steady-state activation, reduced neuronal firing). Including previous studies, functional effects were known for 165 individuals. All 133 individuals carrying GOF variants had either focal (76, groups 1-3), or unclassifiable epilepsy (37), whereas 32 with LOF variants had either generalized (14), no (11) or unclassifiable (5) epilepsy; only two had DEE. Computational modeling in the GOF group revealed a significant correlation between the severity of the electrophysiological and clinical phenotypes. GOF variant carriers responded significantly better to sodium channel blockers (SCBs) than to other anti-seizure medications, and the same applied for all individuals of groups 1-3.In conclusion, our data reveal clear genotype-phenotype correlations between age at seizure onset, type of epilepsy and gain- or loss-of-function effects of SCN8A variants. Generalized epilepsy with absence seizures is the main epilepsy phenotype of LOF variant carriers and the extent of the electrophysiological dysfunction of the GOF variants is a main determinant of the severity of the clinical phenotype in focal epilepsies. Our pharmacological data indicate that SCBs present a therapeutic treatment option in early onset SCN8A-related focal epilepsy. [less ▲]

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See detailSustainable Finance Law: The EU Paradigm and the Way Forward
Alexandraki, Chrysa UL

E-print/Working paper (2021)

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See detailDigitalisierung von Schule und Digitalisierung im Unterricht
Harion, Dominic UL; Pause, Johannes UL

E-print/Working paper (2021)

Detailed reference viewed: 66 (7 UL)
See detailDemocratic Legitimacy of the Single Resolution Board: Is Legality the Right Question?
Mendes, Joana UL

E-print/Working paper (2021)

The choice to entrust EU banking resolution to an independent body opened the familiar democratic legitimacy conundrum that besets independent institutions in national and in EU law. This paper examines ... [more ▼]

The choice to entrust EU banking resolution to an independent body opened the familiar democratic legitimacy conundrum that besets independent institutions in national and in EU law. This paper examines both the conventional view on the relationship between legality control and democratic legitimacy, that the German Federal Constitutional Court endorsed in its SSM/SRM judgment, and the limits of such conception. Conceived as a “compensatory measure”, legal protection through judicial review and internal administrative review enables the Court to bring independent institutions within the (national) constitutional framework that they strain. Law’s binding character becomes a matter of ensuring not only the rule of law but also democracy. Yet, even detailed legal mandates cannot preclude administrative bodies to define the way law is completed and concretised. While the Court does not adhere to a ‘transmission-belt model’ of administrations, not surprisingly – as a court deciding on democratic legitimacy – it falls short of recognising that legality can do very little to ground the democratic legitimacy of fundamental political choices, such as those entrusted to the Single Resolution Board. [less ▲]

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See detailPublic Covid-19 X-ray datasets and their impact on model bias - a systematic review of a significant problem
Garcia Santa Cruz, Beatriz UL; Bossa, Matias Nicolas UL; Sölter, Jan UL et al

E-print/Working paper (2021)

Computer-aided-diagnosis for COVID-19 based on chest X-ray suffers from weak bias assessment and limited quality-control. Undetected bias induced by inappropriate use of datasets, and improper ... [more ▼]

Computer-aided-diagnosis for COVID-19 based on chest X-ray suffers from weak bias assessment and limited quality-control. Undetected bias induced by inappropriate use of datasets, and improper consideration of confounders prevents the translation of prediction models into clinical practice. This study provides a systematic evaluation of publicly available COVID-19 chest X-ray datasets, determining their potential use and evaluating potential sources of bias. Only 5 out of 256 identified datasets met at least the criteria for proper assessment of risk of bias and could be analysed in detail. Remarkably almost all of the datasets utilised in 78 papers published in peer-reviewed journals, are not among these 5 datasets, thus leading to models with high risk of bias. This raises concerns about the suitability of such models for clinical use. This systematic review highlights the limited description of datasets employed for modelling and aids researchers to select the most suitable datasets for their task. [less ▲]

Detailed reference viewed: 66 (2 UL)
See detailAssange’s Extradition: Status Pending
Kafteranis, Dimitrios UL; Andreadakis, Stelios

E-print/Working paper (2021)

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See detailWhich Factors Play a Role in Coco Issuance? Evidence from European Banks.
Wolff, Christian UL

E-print/Working paper (2021)

This paper explores empirically the reasons why some banks issue Contingent Convertible Bonds while others do not. For this purpose we use a binary logistic model and control for the determinants ... [more ▼]

This paper explores empirically the reasons why some banks issue Contingent Convertible Bonds while others do not. For this purpose we use a binary logistic model and control for the determinants suggested by the literature on optimal capital structure which considers four drivers of capital structure: corporate taxes, costs of financial distress, agency costs and asymmetric information.. Our findings suggest that the banks with bigger size and those with higher Tier 1 capital, higher net loans, higher wholesale funding, lower level of leverage and lower risk weighted assets have a higher tendency to issue CoCos. Our results also suggest that banks in countries with higher annual growth rate of GDP per capita and those listed as G-SIBs are more likely to issue CoCos. [less ▲]

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See detailIntroducing the COVID-19 crisis Special Education Needs Coping Survey
Dukes, Daniel; Van Herwegen, Jo; Alessandri, Michael et al

E-print/Working paper (2021)

Individuals with special education needs have been particularly affected by the COVID-19 pandemic as they have been shown to be at high risk of losing medical and institutional support at a time when ... [more ▼]

Individuals with special education needs have been particularly affected by the COVID-19 pandemic as they have been shown to be at high risk of losing medical and institutional support at a time when people are being asked to stay isolated, suffering increased anxiety and depression as a consequence. Their families have often found themselves under tremendous pressure to provide support, engendering financial hardship, and physical and emotional strains. In such times, it is vital that international collaborations assess the impact on the individuals and their families, affording the opportunity to make national and international comparisons of how people have coped and what needs to be done to optimize the measures taken by families, associations and governments. This paper introduces one such collaboration. [less ▲]

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See detailHierarchical a posteriori error estimation of Bank-Weiser type in the FEniCS Project
Bulle, Raphaël UL; Hale, Jack UL; Lozinski, Alexei et al

E-print/Working paper (2021)

In the seminal paper of Bank and Weiser [Math. Comp., 44 (1985), pp.283-301] a new a posteriori estimator was introduced. This estimator requires the solution of a local Neumann problem on every cell of ... [more ▼]

In the seminal paper of Bank and Weiser [Math. Comp., 44 (1985), pp.283-301] a new a posteriori estimator was introduced. This estimator requires the solution of a local Neumann problem on every cell of the finite element mesh. Despite the promise of Bank-Weiser type estimators, namely locality, computational efficiency, and asymptotic sharpness, they have seen little use in practical computational problems. The focus of this contribution is to describe a novel implementation of hierarchical estimators of the Bank-Weiser type in a modern high-level finite element software with automatic code generation capabilities. We show how to use the estimator to drive (goal-oriented) adaptive mesh refinement and to mixed approximations of the nearly-incompressible elasticity problems. We provide comparisons with various other used estimators. An open-source implementation based on the FEniCS Project finite element software is provided as supplementary material. [less ▲]

Detailed reference viewed: 54 (3 UL)
See detailAddressing Hate Speech with Data Science: An Overview from Computer Science Perspective
Lenzini, Gabriele UL; Srba; Pikuliak, Matus et al

E-print/Working paper (2021)

From a computer science perspective, addressing on-line hate speech is a challenging task that is attracting the attention of both industry (mainly social media platform owners) and academia. In this ... [more ▼]

From a computer science perspective, addressing on-line hate speech is a challenging task that is attracting the attention of both industry (mainly social media platform owners) and academia. In this chapter, we provide an overview of state-of-the-art data-science approaches - how they define hate speech, which tasks they solve to mitigate the phenomenon, and how they address these tasks. We limit our investigation mostly to (semi-)automatic detection of hate speech, which is the task that the majority of existing computer science works focus on. Finally, we summarize the challenges and the open problems in the current data-science research and the future directions in this field. Our aim is to prepare an easily understandable report, capable to promote the multidisciplinary character of hate speech research. Researchers from other domains (e.g., psychology and sociology) can thus take advantage of the knowledge achieved in the computer science domain but also contribute back and help improve how computer science is addressing that urgent an d socially relevant issue which is the prevalence of hate speech in social media. [less ▲]

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See detailPanic? Probing Angst over Immigration and Crime
Mahe, Clotilde UL; Parra-Cely, Sergio

E-print/Working paper (2021)

We examine empirically whether immigration affects crime in an emerging country, Ecuador. We exploit the fact that immigration flows of Venezuelans suddenly evolved from voluntary to forced, and occurred ... [more ▼]

We examine empirically whether immigration affects crime in an emerging country, Ecuador. We exploit the fact that immigration flows of Venezuelans suddenly evolved from voluntary to forced, and occurred disproportionately along land borders. We use nationally representative administrative and survey data to precisely estimate an economically null effect of Venezuelan immigration on property and violent crime. We also show that natives are more likely to believe that immigration worsens the economy, despite clear evidence of negative labour market impact due to recent Venezuelan inflows. Results confirm that fears over immigration and crime are not necessarily supported by facts. [less ▲]

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See detailA Robustness Check to Multiple Overlapping Deprivation Analysis (MODA) Methodology: The Case of Nigeria
Fagbeja, Teju; Cebotari, Victor UL

E-print/Working paper (2021)

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See detailSchool-Related Violence in Latin America and the Caribbean: Building an Evidence Base for Stronger Schools
Chávez, Cirenia; Cebotari, Victor UL; José Benítez, Maria et al

E-print/Working paper (2021)

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See detailDigital twinning of Cellular Capsule Technology: emerging outcomes from the perspective of porous media mechanics
Urcun, Stéphane UL

E-print/Working paper (2021)

Spheroids encapsulated within alginate capsules are emerging as suitable in vitro tools to investigate the impact of mechanical forces on tumor growth since the internal tumor pressure can be retrieved ... [more ▼]

Spheroids encapsulated within alginate capsules are emerging as suitable in vitro tools to investigate the impact of mechanical forces on tumor growth since the internal tumor pressure can be retrieved from the deformation of the capsule. Here we focus in particular on the Cellular Capsule Technology (CCT). We show in this contribution that a modeling approach accounting for the triphasic nature of the spheroid (extracellular matrix, tumor cells and interstitial fluid) offers a new perspective of analysis revealing that the pressure retrieved experimentally cannot be interpreted as a direct picture of the pressure sustained by the tumor cells and, as such, cannot therefore be used to quantify the critical pressure which induces stress-induced phenotype switch in tumour cells. The proposed multiphase reactive poro-mechanical model was cross-validated. Parameter sensitivity analyses on the digital twin revealed that the main parameters determining the encapsulated growth configuration are different from those driving growth in free condition, confirming that radically different phenomena are at play.Results reported in this contribution support the idea that multiphase reactive poro-mechanics is an exceptional theoretical framework to attain an in-depth understanding of CCT experiments, to confirm their hypotheses and to further improve their design. [less ▲]

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See detailhttps://arxiv.org/abs/2101.07083
El Emam, Christian UL; Seppi, Andrea

E-print/Working paper (2021)

We prove that any minimal Lagrangian diffeomorphism between two closed spherical surfaces with cone singularities is an isometry, without any assumption on the multiangles of the two surfaces. As an ... [more ▼]

We prove that any minimal Lagrangian diffeomorphism between two closed spherical surfaces with cone singularities is an isometry, without any assumption on the multiangles of the two surfaces. As an application, we show that every branched immersion of a closed surface of constant positive Gaussian curvature in Euclidean three-space is a branched covering onto a round sphere, thus generalizing the classical rigidity theorem of Liebmann to branched immersions. [less ▲]

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See detailPestepidemien in Luxemburg
Pauly, Michel UL

E-print/Working paper (2021)

Detailed reference viewed: 71 (0 UL)
See detailThe Value of Coordination in Multimarket Bidding of Grid Energy Storage
Löhndorf, Nils UL

E-print/Working paper (2021)

Detailed reference viewed: 76 (18 UL)
See detailOn the Weyl problem for complete surfaces in the hyperbolic and anti-de Sitter spaces
Schlenker, Jean-Marc UL

E-print/Working paper (2021)

The classical Weyl problem (solved by Lewy, Alexandrov, Pogorelov, and others) asks whether any metric of curvature K≥0 on the sphere is induced on the boundary of a unique convex body in $\R^3$. The ... [more ▼]

The classical Weyl problem (solved by Lewy, Alexandrov, Pogorelov, and others) asks whether any metric of curvature K≥0 on the sphere is induced on the boundary of a unique convex body in $\R^3$. The answer was extended to surfaces in hyperbolic space by Alexandrov in the 1950s, and a ``dual'' statement, describing convex bodies in terms of the third fundamental form of their boundary (e.g. their dihedral angles, for an ideal polyhedron) was later proved. We describe three conjectural generalizations of the Weyl problem in $\HH^3$ and its dual to unbounded convex subsets and convex surfaces, in ways that are relevant to contemporary geometry since a number of recent results and well-known open problems can be considered as special cases. One focus is on convex domain having a ``thin'' asymptotic boundary, for instance a quasicircle -- this part of the problem is strongly related to the theory of Kleinian groups. A second direction is towards convex subsets with a ``thick'' ideal boundary, for instance a disjoint union of disks -- here one find connections to problems in complex analysis, such as the Koebe circle domain conjecture. A third direction is towards complete, convex disks of infinite area in $\HH^3$ and surfaces in hyperbolic ends -- with connections to questions on circle packings or grafting on the hyperbolic disk. Similar statements are proposed in anti-de Sitter geometry, a Lorentzian cousin of hyperbolic geometry where interesting new phenomena can occur, and in Minkowski and Half-pipe geometry. We also collect some partial new results mostly based on recent works. [less ▲]

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See detailOptimal convergence rates for the invariant density estimation of jump-diffusion processes
Amorino, Chiara UL; Nualart, Eulalia

E-print/Working paper (2021)

We aim at estimating the invariant density associated to a stochastic differential equation with jumps in low dimension, which is for d = 1 and d = 2. We consider a class of jump diffusion processes whose ... [more ▼]

We aim at estimating the invariant density associated to a stochastic differential equation with jumps in low dimension, which is for d = 1 and d = 2. We consider a class of jump diffusion processes whose invariant density belongs to some Hölder space. Firstly, in dimension one, we show that the kernel density estimator achieves the convergence rate 1/T, which is the optimal rate in the absence of jumps. This improves the convergence rate obtained in [Amorino, Gloter (2021)], which depends on the Blumenthal-Getoor index for d = 1 and is equal to log T/T for d = 2. Secondly, we show that is not possible to find an estimator with faster rates of estimation. Indeed, we get some lower bounds with the same rates { 1/T , log T/T } in the mono and bi-dimensional cases, respectively. Finally, we obtain the asymptotic normality of the estimator in the one-dimensional case. [less ▲]

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See detailOn generalized Iwasawa main conjectures and p-adic Stark conjectures for Artin motives
Maksoud, Alexandre UL

E-print/Working paper (2021)

We continue the study of Selmer groups associated with an Artin representation endowed with a p-stabilization which was initiated in arXiv:1811.05368. We formulate a main conjecture and an extra zeros ... [more ▼]

We continue the study of Selmer groups associated with an Artin representation endowed with a p-stabilization which was initiated in arXiv:1811.05368. We formulate a main conjecture and an extra zeros conjecture at all unramified odd primes p, which are shown to imply the p-part of the Tamagawa number conjecture for Artin motives at s=0. We also relate our new conjectures with various cyclotomic Iwasawa main conjectures and p-adic Stark conjectures that appear in the literature. In particular, they provide a natural interpretation for recent conjectures on p-adic L-functions attached to (the adjoint of) a weight one modular form. In the case of monomial representations, we prove that our conjectures are essentially equivalent to some newly introduced Iwasawa-theoretic conjectures for Rubin-Stark elements. [less ▲]

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See detailObserving Many Researchers Using the Same Data and Hypothesis Reveals a Hidden Universe of Uncertainty
Breznau, Nate; Rinke, Eike Mark; Wuttke, Alexander et al

E-print/Working paper (2021)

How does noise generated by researcher decisions undermine the credibility of science? We test this by observing all decisions made among 73 research teams as they independently conduct studies on the ... [more ▼]

How does noise generated by researcher decisions undermine the credibility of science? We test this by observing all decisions made among 73 research teams as they independently conduct studies on the same hypothesis with identical starting data. We find excessive variation of outcomes. When combined, the 107 observed research decisions taken across teams explained at most 2.6 of the total variance in effect sizes and 10 of the deviance in subjective conclusions. Expertise, prior beliefs and attitudes of the researchers explain even less. Each model deployed to test the hypothesis was unique, which highlights a vast universe of research design variability that is normally hidden from view and suggests humility when presenting and interpreting scientific findings. [less ▲]

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See detailTraces and memories of an ongoing pandemic – Yes We Care
Majerus, Benoît UL

in HumaMed@Larca (2021)

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See detailA rigged model of the breast for preoperative surgical planning
Mazier, Arnaud UL; Ribes, Sophie; Testylier, Romain et al

E-print/Working paper (2021)

In breast surgical practice, various scans and medical examinations are performed before surgery. This includes identifying landmarks defining the operating procedure. In most cases, the position of the ... [more ▼]

In breast surgical practice, various scans and medical examinations are performed before surgery. This includes identifying landmarks defining the operating procedure. In most cases, the position of the patient during the scan is vastly different from the one encountered during the operation. We address the challenge of mapping preoperative information to the operating field, with the following constraints: registration has to be done in less than 10 seconds to be compatible with a clinical workflow; the cost of the device must be small and we assume data scarcity, i.e. that our database has twenty scans of patients at most. We build anatomical complexity through a skinning model comprised of scalable bones (to account for pose and morphological variations) and deformable organs (blendshapes, to account for anatomical variations). Similar to animation rigs used in computer graphics, and in contrast to statistical approaches, we manually design a model with some desirable properties, using a reduced number of well-chosen degrees of freedom. Meaningful constraints can be applied to the registration depending on the context, and the trade-off between precision and complexity can be optimized. The result is a surface mesh of the patient obtained in less than 1 minute (scan and reconstruction included) and a registration method that converges within a few seconds (3 maximum), reaching a mean absolute squared error of 2.3 mm for mesh registration and 8.0 mm for anatomical landmarks. The registered model is used to transfer surgical reference patterns on any patient in any position. [less ▲]

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See detailInverse deformation analysis: an experimental and numerical assessment using the FEniCS Project
Mazier, Arnaud UL; Bilger, Alexandre; Forte, Antonio E. et al

E-print/Working paper (2021)

In this paper, we develop a framework for solving inverse deformation problems using the FEniCS Project finite element software. We validate our approach with experimental imaging data acquired from a ... [more ▼]

In this paper, we develop a framework for solving inverse deformation problems using the FEniCS Project finite element software. We validate our approach with experimental imaging data acquired from a soft silicone beam under gravity. In contrast with inverse iterative algorithms that require multiple solutions of a standard elasticity problem, the proposed method can compute the undeformed configuration by solving only one modified elasticity problem. This modified problem has a complexity comparable to the standard one. The framework is implemented within an open-source pipeline enabling the direct and inverse deformation simulation directly from imaging data. We use the high-level Unified Form Language (UFL) of the FEniCS Project to express the finite element model in variational form and to automatically derive the consistent Jacobian. Consequently, the design of the pipeline is flexible: for example, it allows the modification of the constitutive models by changing a single line of code. We include a complete working example showing the inverse deformation of a beam deformed by gravity as supplementary material. [less ▲]

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See detailInnovation in Malmö after the Öresund Bridge
Ejermo, Olof; Hussinger, Katrin UL; Kalash, Basheer et al

E-print/Working paper (2021)

Detailed reference viewed: 38 (13 UL)
See detailGaussian approximation for sums of region-stabilizing scores
Bhattacharjee, Chinmoy UL; Molchanov, Ilya

E-print/Working paper (2021)

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See detailNonparametric needlet estimation for partial derivatives of a probability density function on the d-torus
Durastanti, Claudio; Turchi, Nicola UL

E-print/Working paper (2021)

Detailed reference viewed: 37 (0 UL)
See detailKerr effect in tilted nodal loop semimetals
Ekström, Carl Johan Ingvar UL; Hasdeo, Eddwi Hesky UL; Farias, Maria Belen UL et al

E-print/Working paper (2021)

We investigate the optical activity of tilted nodal loop semimetals. We calculate the full conductivity matrix for a band structure containing a nodal loop with possible tilt in the x−y plane, which ... [more ▼]

We investigate the optical activity of tilted nodal loop semimetals. We calculate the full conductivity matrix for a band structure containing a nodal loop with possible tilt in the x−y plane, which allows us to study the Kerr rotation and ellipticity both for a thin film and a bulk material. We find signatures in the Kerr signal that give direct information about the tilt velocity and direction, the radius of the nodal loop and the internal chemical potential of the system. These findings should serve as guide to understanding optical measurements of nodal loop semimetals and as an additional tool to characterize them. [less ▲]

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See detailA Survey of Requirements for COVID-19 Mitigation Strategies. Part II: Elicitation of Requirements
Jamroga, Wojciech UL

E-print/Working paper (2021)

The COVID-19 pandemic has influenced virtually all aspects of our lives. Across the world, countries have applied various mitigation strategies, based on social, political, and technological instruments ... [more ▼]

The COVID-19 pandemic has influenced virtually all aspects of our lives. Across the world, countries have applied various mitigation strategies, based on social, political, and technological instruments. We postulate that multi-agent systems can provide a common platform to study (and balance) their essential properties. We also show how to obtain a comprehensive list of the properties by ``distilling'' them from media snippets. Finally, we present a preliminary take on their formal specification, using ideas from multi-agent logics. [less ▲]

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See detailPhase transitions and noise sensitivity on the Poisson space via stopping sets and decision trees
Last, Guenter; Peccati, Giovanni UL; Yogeshwaran, Dhandapani

E-print/Working paper (2021)

Detailed reference viewed: 33 (5 UL)
See detailParental Assortative Mating and the Intergenerational Transmission of Human Capital
Bingley, Paul; Cappellari, Lorenzo; Tatsiramos, Konstantinos UL

E-print/Working paper (2021)

We study the contribution of parental similarity in schooling levels to the intergenerational transmission of educational attainment. We develop an empirical model for educational correlations within the ... [more ▼]

We study the contribution of parental similarity in schooling levels to the intergenerational transmission of educational attainment. We develop an empirical model for educational correlations within the family in which parental sorting can translate into intergenerational transmission, or transmission can originate from each parent independently. Estimating the model using educational attainment from Danish population-based administrative data for over 400,000 families, we find that about 75 percent of the intergenerational correlation in education is driven by the joint contribution of the parents. We also document a sizeable secular decline of parental assortative mating in education, with a corresponding fall in joint intergenerational transmission from both parents; a fall compensated by an increase in parent-specific intergenerational transmission, leaving total intergenerational persistence unchanged. The mechanisms of intergenerational transmission have changed, with an increased importance of one-to-one parent-child relationships. [less ▲]

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See detailInternationalisation (at Home) of the Non-Mobile Youth in Europe outside formal Education
Nienaber, Birte UL; Díaz-Catalán, Celia; Kmiotek, Emilia Alicja UL et al

E-print/Working paper (2021)

Mobility is often mentioned as one main aspect of “internationalisation”. However, little is known about the internationalisation at home of non-mobile young people outside formal higher education. In the ... [more ▼]

Mobility is often mentioned as one main aspect of “internationalisation”. However, little is known about the internationalisation at home of non-mobile young people outside formal higher education. In the post- COVID19- era, mobility might remain limited and immobility becomes the rule. Therefore, internationalisation at home plays an important role in times of restricted mobility. To what extent are non-mobile people internationalised? Which factors favour this internationalisation amongst the non-mobiles? We develop a comprehensive index which empirically tests whether and to what extent non-mobiles, become internationalised at home. The answers of 3431 non-mobiles respondents be-tween 18 and 29 years old from six EU countries are analysed. First, we review the concept “internationalisation at home”. We present an empirical measure of internationalisation at home consisting of three dimensions 1) foreign language skills i.e. Eng-lish; 2) multicultural way of living; 3) information about foreign countries. Linear regression models are used to empirically explain which factors influence the internationalisation at home of the non-mobiles on the individual level, using their socio-demographic and social embed-dedness, as well as controlling for the country level. [less ▲]

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See detailRapid Artificial Intelligence Solutions in a Pandemic - The COVID-19-20 Lung CT Lesion Segmentation Challenge.
Roth, Holger; Xu, Ziyue; Diez, Carlos Tor et al

E-print/Working paper (2021)

Artificial intelligence (AI) methods for the automatic detection and quantification of COVID-19 lesions in chest computed tomography (CT) might play an important role in the monitoring and management of ... [more ▼]

Artificial intelligence (AI) methods for the automatic detection and quantification of COVID-19 lesions in chest computed tomography (CT) might play an important role in the monitoring and management of the disease. We organized an international challenge and competition for the development and comparison of AI algorithms for this task, which we supported with public data and state-of-the-art benchmark methods. Board Certified Radiologists annotated 295 public images from two sources (A and B) for algorithms training (n=199, source A), validation (n=50, source A) and testing (n=23, source A; n=23, source B). There were 1,096 registered teams of which 225 and 98 completed the validation and testing phases, respectively. The challenge showed that AI models could be rapidly designed by diverse teams with the potential to measure disease or facilitate timely and patient-specific interventions. This paper provides an overview and the major outcomes of the COVID-19 Lung CT Lesion Segmentation Challenge - 2020. [less ▲]

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See detailHow Many Replicators Does It Take to Achieve Reliability? Investigating Researcher Variability in a Crowdsourced Replication
Breznau, Nate; Rinke, Eike Mark; Wuttke, Alexander et al

E-print/Working paper (2021)

The paper reports findings from a crowdsourced replication. Eighty-four replicator teams attempted to verify results reported in an original study by running the same models with the same data. The ... [more ▼]

The paper reports findings from a crowdsourced replication. Eighty-four replicator teams attempted to verify results reported in an original study by running the same models with the same data. The replication involved an experimental condition. A “transparent” group received the original study and code, and an “opaque” group received the same underlying study but with only a methods section and description of the regression coefficients without size or significance, and no code. The transparent group mostly verified the original study (95.5%), while the opaque group had less success (89.4%). Qualitative investigation of the replicators’ workflows reveals many causes of non-verification. Two categories of these causes are hypothesized, routine and non-routine. After correcting non-routine errors in the research process to ensure that the results reflect a level of quality that should be present in ‘real-world’ research, the rate of verification was 96.1 in the transparent group and 92.4 in the opaque group. Two conclusions follow: (1) Although high, the verification rate suggests that it would take a minimum of three replicators per study to achieve replication reliability of at least 95 confidence assuming ecological validity in this controlled setting, and (2) like any type of scientific research, replication is prone to errors that derive from routine and undeliberate actions in the research process. The latter suggests that idiosyncratic researcher variability might provide a key to understanding part of the “reliability crisis” in social and behavioral science and is a reminder of the importance of transparent and well documented workflows. [less ▲]

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See detailDiversity, National Identity, and Political Participation among Young People in Luxembourg
Procopio, Alessandro UL; Schomaker, Léa UL; Samuel, Robin UL

E-print/Working paper (2021)

Luxembourg is known for its cultural and national diversity. Approximately 48 of the population is foreigners live in Luxembourg. For 15-29-year-olds, this share was approximately 42 in 2019 and 2020 ... [more ▼]

Luxembourg is known for its cultural and national diversity. Approximately 48 of the population is foreigners live in Luxembourg. For 15-29-year-olds, this share was approximately 42 in 2019 and 2020. Furthermore, approximately 185,000 foreign workers commute to Luxembourg daily. Considering this, Luxembourg is an interesting case for investigating national identity and political participation of a diverse society (STATEC 2020a, STATEC 2020b, STATEC 2021). Especially, as the biographies of young people in Luxembourg are becoming increasingly complex (e.g., mixed national parents; highly skilled expatriates), it is worth looking into different aspects and valuations of national identity and political participation of youth in Luxembourg (Amtépé and Hartmann-Hirsch, 2011). In this policy report, we look into the aspects of national identity and how young people living in Luxembourg define a ‘real Luxembourger’ using the Youth Survey Luxembourg (2019) data (Sozio et al., 2020). This will give us the opportunity to investigate what aspects of identity (e.g. Luxembourgish ancestry; the time spent living in Luxembourg) matter for young people to feel part of Luxembourgish society and how these change across different social backgrounds and demographics. The discourse about the interrelations of political participation and youth brings forward the dominant narrative of a disengaging and passive youth. Here, we also investigate these statements in the Luxembourgish context. We analyse the level of interest in politics across young people in Luxembourg and their means of political participation. Finally, we especially investigated the relationship between aspects of national identity, and political interest and engagement of young people in Luxembourg. [less ▲]

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See detailHarmonic amplitude summation for frequency-tagging analysis
Retter, Talia UL; Rossion, Bruno; Schiltz, Christine UL

E-print/Working paper (2021)

In the approach of frequency tagging, stimuli that are presented periodically generate periodic responses of the brain. Following a transformation into the frequency domain, the brain’s response is ... [more ▼]

In the approach of frequency tagging, stimuli that are presented periodically generate periodic responses of the brain. Following a transformation into the frequency domain, the brain’s response is evident often at the frequency of stimulation, F, and its higher harmonics (2F, 3F, etc.). This approach is increasingly used in neuroscience, as it affords objective measures to characterize brain function. However, whether these specific harmonic frequency responses should be combined for analysis, and if so, how, remains an outstanding issue. In most studies, higher harmonic responses have not been described or were described only individually; in other studies, harmonics have been combined with various approaches, e.g., averaging and root mean squared summation. A rationale for these approaches in the context of frequency-based analysis principles, and understanding of how they relate to the brain’s response amplitudes in the time domain, has been missing. Here, with these elements addressed, the summation of (baseline-corrected) harmonic amplitude is recommended. [less ▲]

Detailed reference viewed: 65 (0 UL)
See detailGaussian approximation in random minimal directed spanning trees
Bhattacharjee, Chinmoy UL

E-print/Working paper (2021)

Detailed reference viewed: 28 (2 UL)
See detailEuropean Border Region Studies in Times of Borderization
Wille, Christian UL

E-print/Working paper (2021)

The text originates from a time of borderization, at global level and at the EU’s internal borders. At the latest since covidfencing began in the spring of 2020, many Europeans have become familiar with ... [more ▼]

The text originates from a time of borderization, at global level and at the EU’s internal borders. At the latest since covidfencing began in the spring of 2020, many Europeans have become familiar with border experiences and the practices of civic contestation of borders. With that in mind, the text argues that it is necessary to open European border region studies to the contestation of borders, for which it should enter into dialogue with international (and critical) border studies. [less ▲]

Detailed reference viewed: 62 (2 UL)
See detailA Mixture of Generative Models Strategy Helps Humans Generalize across Tasks
Herce Castañón, Santiago; Cardoso-Leite, Pedro UL; Altarelli, Irene et al

E-print/Working paper (2021)

What role do generative models play in generalization of learning in humans? Our novel multi-task prediction paradigm—where participants complete four sequence learning tasks, each being a different ... [more ▼]

What role do generative models play in generalization of learning in humans? Our novel multi-task prediction paradigm—where participants complete four sequence learning tasks, each being a different instance of a common generative family—allows the separate study of within-task learning (i.e., finding the solution to each of the tasks), and across-task learning (i.e., learning a task differently because of past experiences). The very first responses participants make in each task are not yet affected by within-task learning and thus reflect their priors. Our results show that these priors change across successive tasks, increasingly resembling the underlying generative family. We conceptualize multi-task learning as arising from a mixture-of-generative-models learning strategy, whereby participants simultaneously entertain multiple candidate models which compete against each other to explain the experienced sequences. This framework predicts specific error patterns, as well as a gating mechanism for learning, both of which are observed in the data. [less ▲]

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See detailOptical properties of topological flat and dispersive bands
Habibi, Alireza UL; Musthofa, Ahmad Z.; Adibi, Elaheh et al

E-print/Working paper (2021)

We study the optical properties of topological flat and dispersive bands. Due to their topological nature, there exists an anomalous Hall response which gives rise to a transverse current without applied ... [more ▼]

We study the optical properties of topological flat and dispersive bands. Due to their topological nature, there exists an anomalous Hall response which gives rise to a transverse current without applied magnetic field. The dynamical Hall conductivity of systems with flat bands exhibits a sign change when the excitation energy is on resonance with the band gap, similar to the magnetotransport Hall conductivity profile. The sign change of the Hall conductivity is located at the frequency corresponding to the singularity of the joint density of states, i.e., the van Hove singularity (VHS). For perfectly flat bands, this VHS energy matches the band gap. On the other hand, in the case of dispersive bands, the VHS energy is located above the band gap. As a result, the two features of the Hall conductivity, i.e., the resonant feature at the band gap and the sign change at the VHS energy, become separated. This anomalous Hall response rotates the polarization of an electric field and can be detected in the reflected and transmitted waves, as Kerr and Faraday rotations, respectively, thus allowing a simple optical characterization of topological flat bands. [less ▲]

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Peer Reviewed
See detailAll in one stroke? Intervention Spaces for Dark Patterns
Rossi, Arianna UL; Bongard, Kerstin UL

E-print/Working paper (2021)

This position paper draws from the complexity of dark patterns to develop arguments for differentiated interventions. We propose a matrix of interventions with a \textit{measure axis} (from user-directed ... [more ▼]

This position paper draws from the complexity of dark patterns to develop arguments for differentiated interventions. We propose a matrix of interventions with a \textit{measure axis} (from user-directed to environment-directed) and a \textit{scope axis} (from general to specific). We furthermore discuss a set of interventions situated in different fields of the intervention spaces. The discussions at the 2021 CHI workshop "What can CHI do about dark patterns?" should help hone the matrix structure and fill its fields with specific intervention proposals. [less ▲]

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See detailGaussian fluctuation for Gaussian Wishart matrices of overall correlation
Nourdin, Ivan UL; Pu, Fei

E-print/Working paper (2021)

Detailed reference viewed: 32 (1 UL)
See detailThe Weyl problem for unbounded convex domains in $\HH^3$
Schlenker, Jean-Marc UL

E-print/Working paper (2021)

Let $K\subset \HH^3$ be a convex subset in $\HH^3$ with smooth, strictly convex boundary. The induced metric on $\partial K$ then has curvature $K>-1$. It was proved by Alexandrov that if $K$ is bounded ... [more ▼]

Let $K\subset \HH^3$ be a convex subset in $\HH^3$ with smooth, strictly convex boundary. The induced metric on $\partial K$ then has curvature $K>-1$. It was proved by Alexandrov that if $K$ is bounded, then it is uniquely determined by the induced metric on the boundary, and any smooth metric with curvature $K>-1$ can be obtained. We propose here an extension of the existence part of this result to unbounded convex domains in $\HH^3$. The induced metric on $\partial K$ is then clearly not sufficient to determine $K$. However one can consider a richer data on the boundary including the ideal boundary of $K$. Specifically, we consider the data composed of the conformal structure on the boundary of $K$ in the Poincar\'e model of $\HH^3$, together with the induced metric on $\partial K$. We show that a wide range of "reasonable" data of this type, satisfying mild curvature conditions, can be realized on the boundary of a convex subset in $\HH^3$. We do not consider here the uniqueness of a convex subset with given boundary data. [less ▲]

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See detailUncertainty-driven symmetry-breaking and stochastic stability in a generic differential game of lobbying
Boucekkine, Raouf; Prieur, Fabien; Ruan, Weihua et al

E-print/Working paper (2021)

We study a 2-players stochastic differential game of lobbying. Players have opposite interests; at any date, each player invests in lobbying activities to alter the legislation, the continuous state ... [more ▼]

We study a 2-players stochastic differential game of lobbying. Players have opposite interests; at any date, each player invests in lobbying activities to alter the legislation, the continuous state variable of the game, in her own benefit. The payoffs are quadratic and uncertainty is driven by a Wiener process. We prove that while a symmetric Markov Perfect Equilibrium (MPE) always exists, (two) asymmetric MPE only emerge when uncertainty is large enough. In the latter case, the legislative state converges to a stationary invariant distribution. We fully characterize existence and stochastic stability of the legislative state for both types of MPE. We finally study the implications for rent dissipation asymptotically. We show in particular that while the average rent dissipation is lower with asymmetric equilibria relative to the symmetric, the former yield larger losses at the most likely asymptotic states for large enough but moderate uncertainty. [less ▲]

Detailed reference viewed: 44 (7 UL)
Peer Reviewed
See detailBorder or bordering practice? Changing perspectives on borders and challenges of praxeological approaches
Connor, Ulla UL

E-print/Working paper (2021)

In Border Studies, the ongoing discussions on methodological and theoretical questions have led to the development of transformed approaches and vocabulary for border research. This contribution ... [more ▼]

In Border Studies, the ongoing discussions on methodological and theoretical questions have led to the development of transformed approaches and vocabulary for border research. This contribution highlights the shift from ‘border’ to ‘bordering practice’ and questions its sources in the scientific context, such as the cultural turn and the related practice turn. Despite the popular use of the term ‘practice’ in Border Studies, sociological practice theories are not at the center of the development of dynamic concepts for studying borders. The article emphasizes the compatibility of sociological practice theories with the practice and process orientation in Border Studies. It gives a short overview of praxeological thinking in sociology and identifies methodological challenges for Border Studies targeting the development of praxeological re-search perspectives for borders. [less ▲]

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See detailStages of COVID-19 pandemic and paths to herd immunity by vaccination: dynamical model comparing Austria, Luxembourg and Sweden
Kemp, Francoise UL; Proverbio, Daniele UL; Aalto, Atte UL et al

E-print/Working paper (2021)

Background. Worldwide more than 72 million people have been infected and 1.6 million died with SARS-CoV-2 by 15th December 2020. Non-pharmaceutical interventions which decrease social interaction have ... [more ▼]

Background. Worldwide more than 72 million people have been infected and 1.6 million died with SARS-CoV-2 by 15th December 2020. Non-pharmaceutical interventions which decrease social interaction have been implemented to reduce the spread of SARS-CoV-2 and to mitigate stress on healthcare systems and prevent deaths. The pandemic has been tackled with disparate strategies by distinct countries resulting in different epidemic dynamics. However, with vaccines now becoming available, the current urgent open question is how the interplay between vaccination strategies and social interaction will shape the pandemic in the next months. Methods. To address this question, we developed an extended Susceptible-Exposed-Infectious-Removed (SEIR) model including social interaction, undetected cases and the progression of patients trough hospitals, intensive care units (ICUs) and death. We calibrated our model to data of Luxembourg, Austria and Sweden, until 15th December 2020. We incorporated the effect of vaccination to investigate under which conditions herd immunity would be achievable in 2021. Results. The model reveals that Sweden has the highest fraction of undetected cases, Luxembourg displays the highest fraction of infected population, and all three countries are far from herd immunity as of December 2020. The model quantifies the level of social interactions, and allows to assess the level which would keep Reff(t) below 1. In December 2020, this level is around 1/3 of what it was before the pandemic for all the three countries. The model allows to estimate the vaccination rate needed for herd immunity and shows that 2700 vaccinations/day are needed in Luxembourg to reach it by mid of April and 45,000 for Austria and Sweden. The model estimates that vaccinating the whole country’s population within 1 year could lead to herd immunity by July in Luxembourg and by August in Austria and Sweden. Conclusion. The model allows to shed light on the dynamics of the epidemics in different waves and countries. Our results emphasize that vaccination will help considerably but not immediately and therefore social measures will remain important for several months before they can be fully alleviated. [less ▲]

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See detailTropical Fock-Goncharov coordinates for SL3-webs on surfaces II: naturality
Sun, Zhe UL; Douglas, Daniel C.

E-print/Working paper (2020)

Detailed reference viewed: 33 (0 UL)
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See detailExploring Governance Issues between the SRB and the ESM in the Use of the Common Backstop
Lupinu, Pier Mario UL

E-print/Working paper (2020)

To date, the resolution of the Banco Popular Español, being the first and only resolution case in the euro area, has had the “benefit” of bringing to light several shortfalls of this crisis management ... [more ▼]

To date, the resolution of the Banco Popular Español, being the first and only resolution case in the euro area, has had the “benefit” of bringing to light several shortfalls of this crisis management system. Back then, thanks to the sale of business, the need of the use of the Single Resolution Fund (SRF) has been avoided, prompting criticism on whether the fund had sufficient means to overcome a major widespread crisis. During the period elapsed from the last financial crisis, the euro area banking sector has built capital and liquidity buffers, which were aimed at protecting them for future shocks. Although it is now widely accepted that crises are of a cyclical nature, new risks and the high interconnectivity of today’s economic activities brought an unexpected crisis due to the current pandemic. The consequences of this unprecedented event in modern history had severe effects to the worldwide economy, mostly for the boundless block of labour activities, which caused severe losses for households, enterprises and governments that consequently affected the financial intermediation function of the banks. Concerning the European Stability Mechanism (ESM), the current pandemic has had the effect to put temporary on hold the discussion on the revision of the ESM Treaty, including its role as a Backstop to the SRF, so that the Mechanism could experience a new role through the ESM Pandemic Crisis Support. In such a framework, this paper aims to bring back the attention to the unfinished path in the establishment of the Common Backstop by addressing an important element of risk, namely its decision-making process. The main aim is to explore possible governance issues, which could hamper a timely and effective use of the Common Backstop, in the case that the SRF would be depleted and no alternative funding sources would be available. [less ▲]

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See detailA NEW CORRESPONDENCE BETWEEN TASEPAND BURGERS’ EQUATION
Flandoli, Franco; Gess, Benjamin; Grotto, Francesco UL

E-print/Working paper (2020)

We introduce a new particle model, which we dub Active Bi-Directional Flow, conjugated to the Totally Asymmetric Exclusion Processin discrete time. We then associate to our model intrinsically stochastic ... [more ▼]

We introduce a new particle model, which we dub Active Bi-Directional Flow, conjugated to the Totally Asymmetric Exclusion Processin discrete time. We then associate to our model intrinsically stochastic, non-entropic weak solutions of Burgers’ equation onR, thus linking the latter tothe KPZ universality class. [less ▲]

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See detailWie haben sich emotionale Anforderungen für Arbeitnehmer in Luxemburg über die Zeit entwickelt?
Sischka, Philipp UL; Steffgen, Georges UL

E-print/Working paper (2020)

Im Rahmen dieser Newsletter wird analysiert, wie sich emotionale Anforderungen für Arbeitnehmer in Luxemburg über die letzten Jahre entwickelt haben. Emotionale Anforderungen sind mit reduziertem Well ... [more ▼]

Im Rahmen dieser Newsletter wird analysiert, wie sich emotionale Anforderungen für Arbeitnehmer in Luxemburg über die letzten Jahre entwickelt haben. Emotionale Anforderungen sind mit reduziertem Well-Being assoziiert. Dabei weisen Arbeitnehmer mit ausgeprägten emotionalen Anforderungen insbesondere ein höheres Burnoutlevel auf. Zwischen 2016 und 2020 kam es zu einem deutlichen Anstieg der emotionalen Anforderungen. Arbeitnehmerinnen weisen über die Zeit konstant höhere emotionale Anforderungen auf im Vergleich zu Arbeitnehmern. Insbesondere Arbeitnehmer in akademischen Berufen, Manager und Arbeitnehmer in Dienstleistungsberufen weisen über die Zeit konstant hohe emotionale Anforderungen auf. Bediener von Anlagen und Hilfsarbeitskräfte weisen dagegen einen Anstieg zwischen 2016 und 2020 auf. [less ▲]

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See detailHomogeneous selection promotes microdiversity in the glacier-fed stream microbiome
Fodelianakis, Styliianos; Busi, Susheel Bhanu UL; Wilmes, Paul UL et al

E-print/Working paper (2020)

Microdiversity, the organization of microorganisms into groups with closely related but ecologically different sub-types, is widespread and represents an important linchpin between microbial ecology and ... [more ▼]

Microdiversity, the organization of microorganisms into groups with closely related but ecologically different sub-types, is widespread and represents an important linchpin between microbial ecology and evolution. However, the drivers of microdiversification remain largely unknown. Here we show that selection promotes microdiversity in the microbiome associated with sediments in glacier-fed streams (GFS). Applying a novel phylogenetic framework, we identify several clades that are under homogeneous selection and that contain genera with higher levels of microdiversity than the rest of the genera. Overall these clades constituted ~44% and ~64% of community α-diversity and abundance, and both percentages increased further in GFS that were largely devoid of primary producers. Our findings show that strong homogeneous selection drives the microdiversification of specialized microbial groups putatively underlying their success in the extreme environment of GFS. This microdiversity could be threatened as glaciers shrink, with unknown consequences for microbial diversity and functionality in these ecosystems. [less ▲]

Detailed reference viewed: 92 (2 UL)
See detailAge, Intentions and the Implicit Role of Out-Selection Factors of International Migration
Beine, Michel UL

E-print/Working paper (2020)

In this paper, I propose to isolate the role of age as a self-selection factor of international migration. The role of age is estimated on intended emigration rather than on observed outcomes of migration ... [more ▼]

In this paper, I propose to isolate the role of age as a self-selection factor of international migration. The role of age is estimated on intended emigration rather than on observed outcomes of migration, using individual measures of intended emigration drawn from a large-scale survey conducted by Gallup. I find evidence that age has a monotonic negative effect on desired emigration for the working-age population. The estimations point to a very robust effect, suggesting that an additional year of age decreases the probability of intended emigration by about 0.5%. This effect is steady over different periods of time and for most types of countries of origin. The results contrast with previous evidence obtained on observed outcomes of migration, suggesting that out-selection factors interact with age and shape the demographic profile of migrants. [less ▲]

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See detailIn-plane magnetic field-driven symmetry breaking in topological insulator-based three-terminal junctions
Kölzer, Jonas; Moors, Kristof; Schmidt, Thomas UL et al

E-print/Working paper (2020)

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See detailA hybrid MGA-MSGD ANN training approach for approximate solution of linear elliptic PDEs
Dehghani, Hamidreza UL; Zilian, Andreas UL

E-print/Working paper (2020)

We introduce a hybrid "Modified Genetic Algorithm-Multilevel Stochastic Gradient Descent" (MGA-MSGD) training algorithm that considerably improves accuracy and efficiency of solving 3D mechanical problems ... [more ▼]

We introduce a hybrid "Modified Genetic Algorithm-Multilevel Stochastic Gradient Descent" (MGA-MSGD) training algorithm that considerably improves accuracy and efficiency of solving 3D mechanical problems described, in strong-form, by PDEs via ANNs (Artificial Neural Networks). This presented approach allows the selection of a number of locations of interest at which the state variables are expected to fulfil the governing equations associated with a physical problem. Unlike classical PDE approximation methods such as finite differences or the finite element method, there is no need to establish and reconstruct the physical field quantity throughout the computational domain in order to predict the mechanical response at specific locations of interest. The basic idea of MGA-MSGD is the manipulation of the learnable parameters’ components responsible for the error explosion so that we can train the network with relatively larger learning rates which avoids trapping in local minima. The proposed training approach is less sensitive to the learning rate value, training points density and distribution, and the random initial parameters. The distance function to minimise is where we introduce the PDEs including any physical laws and conditions (so-called, Physics Informed ANN). The Genetic algorithm is modified to be suitable for this type of ANN in which a Coarse-level Stochastic Gradient Descent (CSGD) is exploited to make the decision of the offspring qualification. Employing the presented approach, a considerable improvement in both accuracy and efficiency, compared with standard training algorithms such classical SGD and Adam optimiser, is observed. The local displacement accuracy is studied and ensured by introducing the results of Finite Element Method (FEM) at sufficiently fine mesh as the reference displacements. A slightly more complex problem is solved ensuring the feasibility of the methodology [less ▲]

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See detailEmpowering Large Chemical Knowledge Bases for Exposomics: PubChemLite Meets MetFrag
Schymanski, Emma UL; Kondic, Todor UL; Neumann, Steffen et al

E-print/Working paper (2020)

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See detailCorona-Zeiten, Corona Räume: Alltägliche Raumkonstruktion vor dem Hintergrund der Eindämmung der Covid-19-Pandemie im Saarland
Mellinger, Lukas UL

E-print/Working paper (2020)

In der Reaktion auf die Ausbreitung der Covid-19-Pandemie kam es weltweit für viele Menschen zum Bruch sozialer und räumlicher Routinen. In Deutschland haben die Landesregierungen die führende Rolle beim ... [more ▼]

In der Reaktion auf die Ausbreitung der Covid-19-Pandemie kam es weltweit für viele Menschen zum Bruch sozialer und räumlicher Routinen. In Deutschland haben die Landesregierungen die führende Rolle beim Versuchübernommen, durch Verfügungen und Verordnungen die weitere Ausbreitung der Pandemie einzu-dämmen. In diesem Kontexthatdie Art und Weise wie Gesetze und Regeln Alltagsräume durchdringen für viele Menschen eine neue (unmittelbar erlebbare) Dimension angenommen. Ziel dieses Beitrags ist es,mit einem Fokus auf die getroffenenMaßnahmen der saarländischen Landesregierung diesbezüglich eine lo-kale Perspektive zu entwickeln. Durch die qualitative Methode der Autofotographie werden dabei individu-elle Sichtweisen auf das zugrundeliegendeWechselspiel von Recht, Raum und Gesellschaft in den Vorder-grund der Analyse gestellt.Durch den Blick auf sozialräumliche Zusammenhänge werden so die Auswirkun-gen der getroffenen Maßnahmen hinterfragt. [less ▲]

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See detailRate of estimation for the stationary distribution of jump-processes over anisotropic Holder classes.
Amorino, Chiara UL

E-print/Working paper (2020)

We study the problem of the non-parametric estimation for the density π of the stationary distribution of the multivariate stochastic differential equation with jumps (Xt)0≤t≤T , when the dimension d is ... [more ▼]

We study the problem of the non-parametric estimation for the density π of the stationary distribution of the multivariate stochastic differential equation with jumps (Xt)0≤t≤T , when the dimension d is such that d ≥ 3. From the continuous observa- tion of the sampling path on [0, T ] we show that, under anisotropic H ̈older smoothness constraints, kernel based estimators can achieve fast convergence rates. In particu- lar, they are as fast as the ones found by Dalalyan and Reiss [9] for the estimation of the invariant density in the case without jumps under isotropic H ̈older smooth- ness constraints. Moreover, they are faster than the ones found by Strauch [29] for the invariant density estimation of continuous stochastic differential equations, under anisotropic H ̈older smoothness constraints. Furthermore, we obtain a minimax lower bound on the L2-risk for pointwise estimation, with the same rate up to a log(T) term. It implies that, on a class of diffusions whose invariant density belongs to the anisotropic Holder class we are considering, it is impossible to find an estimator with a rate of estimation faster than the one we propose. [less ▲]

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See detailGender bias in magazines oriented to men and women: a computational approach
Kozlowski, Diego UL; Lozano, Gabriela; Fletcher, Carla M. et al

E-print/Working paper (2020)

Cultural products are a source to acquire individual values and behaviours. Therefore, the differences in the content of the magazines aimed specifically at women or men are a means to create and ... [more ▼]

Cultural products are a source to acquire individual values and behaviours. Therefore, the differences in the content of the magazines aimed specifically at women or men are a means to create and reproduce gender stereotypes. In this study, we compare the content of a women-oriented magazine with that of a men-oriented one, both produced by the same editorial group, over a decade (2008-2018). With Topic Modelling techniques we identify the main themes discussed in the magazines and quantify how much the presence of these topics differs between magazines over time. Then, we performed a word-frequency analysis to validate this methodology and extend the analysis to other subjects that did not emerge automatically. Our results show that the frequency of appearance of the topics Family, Business and Women as sex objects, present an initial bias that tends to disappear over time. Conversely, in Fashion and Science topics, the initial differences between both magazines are maintained. Besides, we show that in 2012, the content associated with horoscope increased in the women-oriented magazine, generating a new gap that remained open over time. Also, we show a strong increase in the use of words associated with feminism since 2015 and specifically the word abortion in 2018. Overall, these computational tools allowed us to analyse more than 24,000 articles. Up to our knowledge, this is the first study to compare magazines in such a large dataset, a task that would have been prohibitive using manual content analysis methodologies [less ▲]

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See detailOn the nonparametric inference of coefficients of self-exciting jump-diffusion
Amorino, Chiara UL; Dion, Charlotte; Gloter, Arnaud et al

E-print/Working paper (2020)

In this paper, we consider a one-dimensional diffusion process with jumps driven by a Hawkes process. We are interested in the estimations of the volatility function and of the jump function from discrete ... [more ▼]

In this paper, we consider a one-dimensional diffusion process with jumps driven by a Hawkes process. We are interested in the estimations of the volatility function and of the jump function from discrete high-frequency observations in long time horizon. We first propose to estimate the volatility coefficient. For that, we introduce in our estimation procedure a truncation function that allows to take into account the jumps of the process and we estimate the volatility function on a linear subspace of L 2 (A) where A is a compact interval of R. We obtain a bound for the empirical risk of the volatility estimator and establish an oracle inequality for the adaptive estimator to measure the performance of the procedure. Then, we propose an estimator of a sum between the volatility and the jump coefficient modified with the conditional expectation of the intensity of the jumps. The idea behind this is to recover the jump function. We also establish a bound for the empirical risk for the non-adaptive estimator of this sum and an oracle inequality for the final adaptive estimator. We conduct a simulation study to measure the accuracy of our estimators in practice and we discuss the possibility of recovering the jump function from our estimation procedure. [less ▲]

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See detailConical SL(3) foams
Khovanov, Mikhail; Robert, Louis-Hadrien UL

E-print/Working paper (2020)

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See detailGetzler-Kapranov complexes and moduli stacks of curves
Kalugin, Alexey UL

E-print/Working paper (2020)

Detailed reference viewed: 147 (17 UL)
See detailSARS-CoV-2 Transmission in Educational Settings During an Early Summer Epidemic Wave in Luxembourg
Mossong, Joël; Mombaerts, Laurent UL; Veiber, Lisa UL et al

E-print/Working paper (2020)

Background: The role of schools and children in the transmission of SARS-CoV-2 remains to be determined. Following a first wave in spring and gradual easing of lockdown, Luxembourg experienced an early ... [more ▼]

Background: The role of schools and children in the transmission of SARS-CoV-2 remains to be determined. Following a first wave in spring and gradual easing of lockdown, Luxembourg experienced an early second epidemic wave before the start of summer school holidays on 15th July. This provided the opportunity to study the role of school-age children and school settings in SARS-CoV-2 transmission. More specifically, we compared the incidence in school-age children, teachers and the general working population, and estimated the number of secondary transmissions occurring at schools using contact tracing data. Findings: While SARS-CoV-2 incidence was much higher in adults aged 20 and above than in children aged 0 to 19 during the first wave in spring, no significant difference was found during the second wave in early summer. The incidence during the second wave was similar for pupils, teachers and the general working population. Based on a total of 424 reported confirmed COVID-19 cases in school-age children and teachers, we estimate that 179 index cases caused 49 secondary transmissions in schools. While some small clusters of mainly student-to-student transmission within the same class were identified, we did not observe any large outbreaks with multiple generations of infection. Interpretation: Transmission of SARS-CoV-2 within Luxembourg schools was limited during the early summer epidemic wave in 2020. Precautionary measures including physical distancing as well as easy access to testing, systematic contact tracing appears to have been successful in mitigating transmission within educational settings. Funding Statement: LV is supported by the Luxembourg National Research Fund grant COVID-19/2020- 1/14701707/REBORN, LM is supported by Luxembourg National Research Fund grant COVID19/14863306/PREVID, PW is supported by the European Research Council (ERC-CoG 863664). Declaration of Interests: No competing interests. Ethics Approval Statement: The Health Directorate has the legal permission to process patient confidential information for national surveillance of communicable diseases in general and contact tracing for the COVID-19 pandemic and individual patient consent is not required. [less ▲]

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See detailAnonymous proof-ofasset transactions using pairing-based designated blind signatures
Sharma, Neetu; Sahu, Rajeev Anand UL; Saraswat, Vishal et al

E-print/Working paper (2020)

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See detailDimension-free Harnack inequalities for conjugate heat equations and their applications to geometric flows
Cheng, Li-Juan; Thalmaier, Anton UL

E-print/Working paper (2020)

Let M be a differentiable manifold endowed with a family of complete Riemannian metrics g(t) evolving under a geometric flow over the time interval [0,T[. In this article, we give a probabilistic ... [more ▼]

Let M be a differentiable manifold endowed with a family of complete Riemannian metrics g(t) evolving under a geometric flow over the time interval [0,T[. In this article, we give a probabilistic representation for the derivative of the corresponding conjugate semigroup on M which is generated by a Schrödinger type operator. With the help of this derivative formula, we derive fundamental Harnack type inequalities in the setting of evolving Riemannian manifolds. In particular, we establish a dimension-free Harnack inequality and show how it can be used to achieve heat kernel upper bounds in the setting of moving metrics. Moreover, by means of the supercontractivity of the conjugate semigroup, we obtain a family of canonical log-Sobolev inequalities. We discuss and apply these results both in the case of the so-called modified Ricci flow and in the case of general geometric flows. [less ▲]

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See detailBetween Discretion and Proportionality: The Duty of Care in EU Judicial Review
Hofmann, Herwig UL

E-print/Working paper (2020)

Detailed reference viewed: 57 (3 UL)
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See detailA generalization of Krull-Webster's theory to higher order convex functions: multiple gamma-type functions
Marichal, Jean-Luc UL; Zénaïdi, Naïm

E-print/Working paper (2020)

We provide uniqueness and existence results for the eventually $p$-convex and eventually $p$-concave solutions to the difference equation $\Delta f=g$ on the open half-line $(0,\infty)$, where $p$ is a ... [more ▼]

We provide uniqueness and existence results for the eventually $p$-convex and eventually $p$-concave solutions to the difference equation $\Delta f=g$ on the open half-line $(0,\infty)$, where $p$ is a given nonnegative integer and $g$ is a given function satisfying the asymptotic property that the sequence $n\mapsto\Delta^p g(n)$ converges to zero. These solutions, that we call $\log\Gamma_p$-type functions, include various special functions such as the polygamma functions, the logarithm of the Barnes $G$-function, and the Hurwitz zeta function. Our results generalize to any nonnegative integer $p$ the special case when $p=1$ obtained by Krull and Webster, who both generalized Bohr-Mollerup-Artin's characterization of the gamma function. We also follow and generalize Webster's approach and provide for $\log\Gamma_p$-type functions analogues of Euler's infinite product, Weierstrass' infinite product, Gauss' limit, Gauss' multiplication formula, Legendre's duplication formula, Euler's constant, Stirling's constant, Stirling's formula, Wallis's product formula, and Raabe's formula for the gamma function. We also introduce and discuss analogues of Binet's function, Burnside's formula, Fontana-Mascheroni's series, Euler's reflection formula, and Gauss' digamma theorem. Lastly, we apply our results to several special functions, including the Hurwitz zeta function and the generalized Stieltjes constants, and show through these examples how powerful is our theory to produce formulas and identities almost systematically. [less ▲]

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See detailEnforcing EU law: the case of the whistle-blower
Kafteranis, Dimitrios UL

E-print/Working paper (2020)

Detailed reference viewed: 21 (0 UL)
See detailTime to reconsider Strasbourg's whistleblower case law
Kafteranis, Dimitrios UL; Robert, Brockhaus

E-print/Working paper (2020)

Detailed reference viewed: 33 (0 UL)
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See detailThe European Citizens` Initiative: diversifying policy debates at European level
Hiry, Jasmin UL

E-print/Working paper (2020)

Detailed reference viewed: 34 (1 UL)
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See detailOn the Composition and Limitations of Publicly Available COVID-19 X-Ray Imaging Datasets
Garcia Santa Cruz, Beatriz UL; Sölter, Jan UL; Bossa, Matias Nicolas UL et al

E-print/Working paper (2020)

 Machine learning based methods for diagnosis and progression prediction of COVID-19 from imaging data have gained significant attention in the last months, in particular by the use of deep learning ... [more ▼]

 Machine learning based methods for diagnosis and progression prediction of COVID-19 from imaging data have gained significant attention in the last months, in particular by the use of deep learning models. In this context hundreds of models where proposed with the majority of them trained on public datasets. Data scarcity, mismatch between training and target population, group imbalance, and lack of documentation are important sources of bias, hindering the applicability of these models to real-world clinical practice. Considering that datasets are an essential part of model building and evaluation, a deeper understanding of the current landscape is needed. This paper presents an overview of the currently public available COVID-19 chest X-ray datasets. Each dataset is briefly described and potential strength, limitations and interactions between datasets are identified. In particular, some key properties of current datasets that could be potential sources of bias, impairing models trained on them are pointed out. These descriptions are useful for model building on those datasets, to choose the best dataset according the model goal, to take into account the specific limitations to avoid reporting overconfident benchmark results, and to discuss their impact on the generalisation capabilities in a specific clinical setting. [less ▲]

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See detailTerritorial patterns and relations in Austria
Szendrei, Greta UL; Evrard, Estelle UL; Nienaber, Birte UL et al

E-print/Working paper (2020)

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See detailOn the Gauss map of equivariant immersions in hyperbolic space
El Emam, Christian UL; Seppi, Andrea

E-print/Working paper (2020)

Given an oriented immersed hypersurface in hyperbolic space H^{n+1}, its Gauss map is defined with values in the space of oriented geodesics of H^{n+1}, which is endowed with a natural para-Kähler ... [more ▼]

Given an oriented immersed hypersurface in hyperbolic space H^{n+1}, its Gauss map is defined with values in the space of oriented geodesics of H^{n+1}, which is endowed with a natural para-Kähler structure. In this paper we address the question of whether an immersion G of the universal cover of an n-manifold M, equivariant for some group representation of π1(M) in Isom(H^{n+1}), is the Gauss map of an equivariant immersion in H^{n+1}. We fully answer this question for immersions with principal curvatures in (−1,1): while the only local obstructions are the conditions that G is Lagrangian and Riemannian, the global obstruction is more subtle, and we provide two characterizations, the first in terms of the Maslov class, and the second (for M compact) in terms of the action of the group of compactly supported Hamiltonian symplectomorphisms [less ▲]

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See detailThe Flow of Information Among Authorities Involved in the Banking Union’s Resolution Procedure: The Case of the SRB and the ECB
Lupinu, Pier Mario UL

E-print/Working paper (2020)

The flow of information is vital for the smooth functioning and certainty of the successful outcome of a resolution procedure during resolution planning and execution. As a result, the exchange of ... [more ▼]

The flow of information is vital for the smooth functioning and certainty of the successful outcome of a resolution procedure during resolution planning and execution. As a result, the exchange of relevant information has become highly influential in current debates. This article will focus on the exchange of information between the Single Resolution Board (SRB) and the European Central Bank (ECB). Firstly, the Authorities decided to arrange the rules for sharing information bilaterally in the form of a Memorandum of Understanding (MoU). While this framework of cooperation and exchange of information between the SRB and the ECB constitutes an obligation under Article 30(7) of the Single Resolution Mechanism Regulation (SRMR), it was drafted in the non-binding form of an MoU. The general purpose of an MoU is to establish the basis for cooperation and convergence of intentions. Such foundations aim to strengthen the resolution procedure by joining forces to obtain more accurate and complete data with better coordination of tasks and resources in order to achieve the most solid result possible within a tighter timeframe. [less ▲]

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See detailUAV Relay-Assisted Emergency Communications in IoT Networks: Resource Allocation and Trajectory Optimization
Tran Dinh, Hieu UL; Nguyen, van Dinh UL; Gautam, Sumit UL et al

E-print/Working paper (2020)

Unmanned aerial vehicle (UAV) communication has emerged as a prominent technology for emergency communications (e.g., natural disaster) in Internet of Things (IoT) networks to enhance the ability of ... [more ▼]

Unmanned aerial vehicle (UAV) communication has emerged as a prominent technology for emergency communications (e.g., natural disaster) in Internet of Things (IoT) networks to enhance the ability of disaster prediction, damage assessment, and rescue operations promptly. In this paper, a UAV is deployed as a flying base station (BS) to collect data from time-constrained IoT devices and then transfer the data to a ground gateway (GW). In general, the latency constraint at IoT users and the limited storage capacity of UAV highly hinder practical applications of UAV-assisted IoT networks. In this paper, full-duplex (FD) technique is adopted at the UAV to overcome these challenges. In addition, half-duplex (HD) scheme for UAV-based relaying is also considered to provide a comparative study between two modes (viz., FD and HD). Herein, a device is successfully served iff its data is collected by UAV and conveyed to GW within the flight time. In this context, we aim at maximizing the number of served IoT devices by jointly optimizing bandwidth and power allocation, as well as the UAV trajectory, while satisfying the requested timeout (RT) requirement of each device and the UAV’s limited storage capacity. The formulated optimization problem is troublesome to solve due to its non-convexity and combinatorial nature. Toward appealing applications, we first relax binary variables into continuous values and transform the original problem into a more computationally tractable form. By leveraging inner approximation framework, we derive newly approximated functions for non-convex parts and then develop a simple yet efficient iterative algorithm for its solutions. Next, we attempt to maximize the total throughput subject to the number of served IoT devices. Finally, numerical results show that the proposed algorithms significantly outperform benchmark approaches in terms of the number of served IoT devices and the amount of collected data. [less ▲]

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See detailThe prestige and status of research fields within mathematics
Schlenker, Jean-Marc UL

E-print/Working paper (2020)

While the ``hierarchy of science'' has been widely analysed, there is no corresponding study of the status of subfields within a given scientific field. We use bibliometric data to show that subfields of ... [more ▼]

While the ``hierarchy of science'' has been widely analysed, there is no corresponding study of the status of subfields within a given scientific field. We use bibliometric data to show that subfields of mathematics have a different ``standing'' within the mathematics community. Highly ranked departments tend to specialize in some subfields more than in others, and the same subfields are also over-represented in the most selective mathematics journals or among recipients of top prizes. Moreover this status of subfields evolves markedly over the period of observation (1984--2016), with some subfields gaining and others losing in standing. The status of subfields is related to different publishing habits, but some of those differences are opposite to those observed when considering the hierarchy of scientific fields. We examine possible explanations for the ``status'' of different subfields. Some natural explanations -- availability of funding, importance of applications -- do not appear to function, suggesting that factors internal to the discipline are at work. We propose a different type of explanation, based on a notion of ``focus'' of a subfield, that might or might not be specific to mathematics. [less ▲]

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See detailElection Verifiability Revisited: Automated Security Proofs and Attacks on Helios and Belenios
Baloglu, Sevdenur UL; Bursuc, Sergiu UL; Mauw, Sjouke UL et al

E-print/Working paper (2020)

Election verifiability aims to ensure that the outcome produced by electronic voting systems correctly reflects the intentions of eligible voters, even in the presence of an adversary that may corrupt ... [more ▼]

Election verifiability aims to ensure that the outcome produced by electronic voting systems correctly reflects the intentions of eligible voters, even in the presence of an adversary that may corrupt various parts of the voting infrastructure. Protecting such systems from manipulation is challenging because of their distributed nature involving voters, election authorities, voting servers and voting platforms. An adversary corrupting any of these can make changes that, individually, would go unnoticed, yet in the end will affect the outcome of the election. It is, therefore, important to rigorously evaluate whether the measures prescribed by election verifiability achieve their goals. We propose a formal framework that allows such an evaluation in a systematic and automated way. We demonstrate its application to the verification of various scenarios in Helios and Belenios, two prominent internet voting systems. For Helios, our analysis is the first one to be, at the same time, fully automated (with the Tamarin protocol prover) and to precisely capture its end-to-end verifiability guarantees, allow- ing us to derive new security proofs and new attacks on deployed versions of it. For Belenios, similarly, we capture precisely the end-to-end verifiability guarantees when all election authorities are corrupted, which is outside the scope of previous formal definitions. We also find new attacks that apply in weaker corruption scenarios that are expected to be secure. In general, our framework allows a unified analy- sis and comparison of cryptographic voting protocols, corruption scenarios and verifiability procedures towards ensuring the end goal of election integrity. [less ▲]

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See detailWorking Document to support the EMN Inform: EU and OECD Member States responses to managing residence permits and migrant unemployment during the COVID-19 pandemic
Sommarribas, Adolfo UL; Sheridan, Anne

E-print/Working paper (2020)

The COVID-19 took by surprise most Member States of the European Union, as they underestimated the rapid spread of the contagion in the continent. The response of the Member States was asymmetrical ... [more ▼]

The COVID-19 took by surprise most Member States of the European Union, as they underestimated the rapid spread of the contagion in the continent. The response of the Member States was asymmetrical, individualistic and significantly slow. The first measures taken were to close down the internal borders. The response of the European Union was even slower to the point that and it was not until March 17th 2020 that the external borders were closed. These actions affected legal migration into the European Union from four perspectives: 1) it affected the mobility of those third country nationals who were on temporary stay in the Member States; 2) the entry of third country nationals to do seasonal work; 3) the entry and stay of legal migrants; and 4) the status quo of the third country nationals already residing in the Member States, especially those who have a loss of income. This article will deal with the measures taken by Member States on who to manage the immigration services during the crisis as well as the measures taken in order to deal with overstayers, seasonal workers and other legal migrants. Finally, we will focus in the vulnerable situation that third-country national salaried workers are exposed due to the loss of income or loss of employment in the Member States and the risk of being returned to their country of origin. [less ▲]

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See detailTesting informed SIR based epidemiological model for COVID-19 in Luxembourg
Sauter, Thomas UL; Pires Pacheco, Maria Irene UL

E-print/Working paper (2020)

The interpretation of the number of COVID-19 cases and deaths in a country or region is strongly dependent on the number of performed tests. We developed a novel SIR based epidemiological model (SIVRT ... [more ▼]

The interpretation of the number of COVID-19 cases and deaths in a country or region is strongly dependent on the number of performed tests. We developed a novel SIR based epidemiological model (SIVRT) which allows the country-specific integration of testing information and other available data. The model thereby enables a dynamic inspection of the pandemic and allows estimating key figures, like the number of overall detected and undetected COVID-19 cases and the infection fatality rate. As proof of concept, the novel SIVRT model was used to simulate the first phase of the pandemic in Luxembourg. An overall number of infections of 13.000 and an infection fatality rate of 1,3 was estimated, which is in concordance with data from population-wide testing. Furthermore based on the data as of end of May 2020 and assuming a partial deconfinement, an increase of cases is predicted from mid of July 2020 on. This is consistent with the current observed rise and shows the predictive potential of the novel SIVRT model. [less ▲]

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