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See detailSpectre des longueurs des représentations d'un groupe de surface
Tholozan, Nicolas UL

Presentation (2015, May 22)

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See detailLe spectre du tronc commun
Gardin, Matias UL; Barbu, Ragnhild UL; Rothmüller, Barbara UL

Article for general public (2016)

Pourquoi le Luxembourg s'inquiète-t-il toujours de l'école polyvalente, une réforme adoptée par le Parlement national en 1979, et qui ne fut jamais été appliquée comme prévu dans les années 1980 ? Plus de ... [more ▼]

Pourquoi le Luxembourg s'inquiète-t-il toujours de l'école polyvalente, une réforme adoptée par le Parlement national en 1979, et qui ne fut jamais été appliquée comme prévu dans les années 1980 ? Plus de trois décennies se sont écoulées et, pour un certain nombre de raisons, le spectre de l'école polyvalente continue à hanter les acteurs de l'éducation publique au Luxembourg. Cette inquiétude se manifeste notamment par un désir constant de la part des gouvernements luxembourgeois successifs d'augmenter le nombre d'élèves étudiant au lycée classique et d’autre part d'abaisser le nombre d'élèves qui poursuivent leurs études en régime préparatoire. Le ministre de l'Éducation Claude Meisch et le secrétaire d'État à l'Éducation Marc Hansen ont fait savoir qu'ils étaient prêts à aborder la question très prochainement. [less ▲]

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See detailUn spectre hante le monde...
Scuto, Denis UL

Article for general public (2018)

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See detailA spectrophotometric assay of D-glucuronate based on Escherichia coli uronate isomerase and mannonate dehydrogenase
Linster, Carole UL; Van Schaftingen, Emile

in Protein Expression & Purification (2004), 37(2), 352-60

Escherichia coli uronate isomerase and mannonate dehydrogenase were overexpressed in E. coli BL21(DE3)pLysS cells and purified to near-homogeneity. The kinetic properties of the two enzymes were ... [more ▼]

Escherichia coli uronate isomerase and mannonate dehydrogenase were overexpressed in E. coli BL21(DE3)pLysS cells and purified to near-homogeneity. The kinetic properties of the two enzymes were investigated. The isomerase was found to be inhibited by EDTA and to be stimulated by Zn(2+), Co(2+), and Mn(2+), but not by Mg(2+) or Ca(2+). Both enzymes were used to develop a sensitive spectrophotometric assay, in which D-glucuronate is converted to D-mannonate with concomitant oxidation of NADH to NAD(+). The sensitivity of this assay permits the detection of less than 1 nmol D-glucuronate. This assay can also be used to determine the concentration of beta-glucuronides and glucuronate 1-phosphate after enzymatic hydrolysis of these compounds with beta-glucuronidase or alkaline phosphatase. [less ▲]

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See detailSpectroscopic Studies of dissimilar Al-Cu laser welding
Schmalen, Pascal Guy UL; Plapper, Peter UL

in proceedings of asme msec 2018 (2018)

This paper describes a novel method to analyze the effect of the fiber laser induced plasma on welding of dissimilar Al and Cu. Based on spectroscopic studies, specific wavelengths were found to be ... [more ▼]

This paper describes a novel method to analyze the effect of the fiber laser induced plasma on welding of dissimilar Al and Cu. Based on spectroscopic studies, specific wavelengths were found to be suitable for process monitoring during laser welding. For aluminum, the double peak at 394.4 and 396.1 nm was studied, for cu the 578 nm peak was studied. The characteristic peaks were observed by multiple photodiodes equipped with narrow optical filters with varying FWHM. Analyzing the plasma emissions of the process enabled to detect material changes in the plasma plume. This novel method has the advantage of higher sampling rate combined with reduced costs compared to a spectrometer and is thus able to capture the process dynamics. [less ▲]

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See detailSpectroscopie expérimentale et théorique du graphène fonctionnalisé
Wirtz, Ludger UL

Scientific Conference (2012)

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See detailSpectrum Allocation for Decentralized Transmission Strategies: Properties of Nash Equilibria
von Wrycza, Peter; Shankar, Bhavani UL; Bengtsson, Mats et al

in EURASIP Journal on Advances in Signal Processing (2009)

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See detailSpectrum Awareness and Exploitation for Cognitive Satellite Communications
Guidotti, Alessandro; Icolari, Vincenzo; Tarchi, Danielle et al

in European Conference on Networks and Communications (EuCNC), Paris, France, Jun 2015. (2015)

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See detailSpectrum Monitoring Algorithms for Wireless and Satellite Communications
Politis, Christos UL

Doctoral thesis (2018)

Nowadays, there is an increasing demand for more efficient utilization of the radio frequency spectrum as new terrestrial and space services are deployed resulting in the congestion of the already crowded ... [more ▼]

Nowadays, there is an increasing demand for more efficient utilization of the radio frequency spectrum as new terrestrial and space services are deployed resulting in the congestion of the already crowded frequency bands. In this context, spectrum monitoring is a necessity. Spectrum monitoring techniques can be applied in a cognitive radio network, exploiting the spectrum holes and allowing the secondary users to have access in an unlicensed frequency band for them, when it is not occupied by the primary user. Furthermore, spectrum monitoring techniques can be used for interference detection in wireless and satellite communications. These two topics are addressed in this thesis. In the beginning, a detailed survey of the existing spectrum monitoring techniques according to the way that cognitive radio users 1) can detect the presence or absence of the primary user; and 2) can access the licensed spectrum is provided. Subsequently, an overview of the problem of satellite interference and existing methods for its detection are discussed, while the contributions of this thesis are presented as well. Moreover, this thesis discusses some issues in a cognitive radio system such as the reduction of the secondary user's throughput of the conventional \listen before talk" access method in the spectrum. Then, the idea of simultaneous spectrum sensing and data transmission through the collaboration of the secondary transmitter with receiver is proposed to address these concerns. First, the secondary receiver decodes the signal from the secondary transmitter, then, removes it from the total received signal and finally, applies spectrum sensing in the remaining signal in order to decide if the primary user is active or idle. The effects of the imperfect signal cancellation due to decoding errors, which are ignored in the existing literature, are considered in our analysis. The analytical expressions for the probabilities of false alarm and detection are derived and numerical results through simulations are also presented to validate the proposed study. Furthermore, the threat of interference for the satellite communications services is studied in this thesis. It proposes the detection of interference on-board the satellite by introducing a spectrum monitoring unit within the satellite transponder. This development will bring several benefits such as faster reaction time and simplification of the ground stations in multi-beam satellite systems. Then, two algorithms for the detection of interference are provided. The first detection scheme is based on energy detector with signal cancellation exploiting the pilot symbols. The second detection scheme considers a two-stage detector, where first, the energy detector with signal cancellation in the pilot domain is performed, and if required, an energy detector with signal cancellation in the data domain is carried out in the second stage. Moreover, the analytical expressions for the probabilities of false alarm and detection are derived and numerical results through simulations are provided to verify the accuracy of the proposed analysis. Finally, this thesis goes one step further and the developed algorithms are evaluated experimentally using software defined radios, particularly universal software radio peripherals (USRPs), while it concludes discussing some open research topics. [less ▲]

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See detailThe spectrum of circulating RNA: A window into systems toxicology
Wang, Kai; Yuan, Yue; Cho, Ji-Hoon et al

in Toxicological Sciences (2013), 132(2), 478492

Adverse effects caused by therapeutic drugs are a serious and costly health concern. Despite the body’s systemic responses to therapeutics, the liver is often the focus of damage and is usually the focus ... [more ▼]

Adverse effects caused by therapeutic drugs are a serious and costly health concern. Despite the body’s systemic responses to therapeutics, the liver is often the focus of damage and is usually the focus of studies of toxic effects due to its active roles in the metabolism of xenobiotics. It is extremely difficult, however, to assess systemic responses with currently available methods. Comprehensive cataloging of cell-free circulating RNAs using next-generation sequencing technology may open a window to assess drug-associated adverse effects at the systems level. To explore this potential, we conducted an RNA profiling study using the well-characterized acetaminophen overdose mouse model on liver and plasma with microarray and next-generation sequencing platforms, respectively. After drug treatment, the levels of a number of transcripts, both endogenous and exogenous RNAs, showed significant changes in plasma, reflecting not only the classical liver injury induced by acetaminophen overdose but also damage in tissues other than the liver. The changes in exogenous RNAs also reflect alteration on dieting behavior after acetaminophen overdose. Besides reporting an extensive list of circulating RNAbased biomarker candidates, this study illustrates the possibility of using circulating RNAs to assess global effects of therapeutics. This could also lead to a new approach for a more comprehensive assessment of the efficacy and safety of therapeutics. [less ▲]

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See detailSpectrum of GABAA receptor variants in epilepsy
Maljevic, Snezana; Møller, Rikke S.; Reid, Christopher A. et al

in Current Opinion in Neurology (2019)

Purpose of review: Recent publications point to an increasingly important role of variants in genes encoding GABAA receptor subunits associated with both common and rare forms of epilepsies. The aim of ... [more ▼]

Purpose of review: Recent publications point to an increasingly important role of variants in genes encoding GABAA receptor subunits associated with both common and rare forms of epilepsies. The aim of this review is to give an overview of the current clinical phenotypes, genetic findings and pathophysiological mechanisms related to GABAA receptor variants. Recent findings: Early work showed that inherited variants in GABRG2 and GABRA1 cause relatively mild forms of monogenic epilepsies in large families. More recent studies have revealed that de novo variants in several GABAA receptor genes cause severe developmental and epileptic encephalopathies, inherited variants cause remarkably variable phenotypes within the same pedigrees ranging from asymptomatic carriers to developmental and epileptic encephalopathies, and variants in all GABAA receptor genes are enriched in common forms of epilepsy, namely rolandic epilepsy and genetic generalized epilepsy. Analyses from cellular expression systems and mouse models suggest that all variants cause a loss of GABAA receptor function resulting in GABAergic disinhibition. Summary: Genetic studies have revealed a crucial role of the GABAergic system in the underlying pathogenesis of various forms of common and rare epilepsies. Our understanding of functional consequences of GABAA receptor variants provide an opportunity to develop precision-based therapeutic strategies that are hopefully free from the side-effect burden seen with currently available GABAergic drugs. [less ▲]

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See detailSpectrum of phenotypes and genotypes in Parkinson's disease.
Riess, Olaf; Krüger, Rejko UL; Schulz, Jorg B.

in Journal of neurology (2002), 249 Suppl 3

The pathogenesis of Parkinsons disease (PD) is currently unknown. Environmental and genetic factors might contribute to the neurodegenerative process. Genetic mapping approaches in rare familial cases ... [more ▼]

The pathogenesis of Parkinsons disease (PD) is currently unknown. Environmental and genetic factors might contribute to the neurodegenerative process. Genetic mapping approaches in rare familial cases with autosomal recessive and autosomal dominant inheritance of PD suggest wide genetic heterogeneity of the disease. These gene loci in turn allow now a more specific clinical investigation of affected families to study the clinical heterogeneity of PD. The recent identification of mutations in three genes involved in protein degradation and aggregation in familial PD does now facilitate the deciphering of other genes involved in the pathogenesis of the disease. [less ▲]

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See detailSpectrum Sensing in Dual Polarized Fading Channels for Cognitive SatComs
Sharma, Shree Krishna UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in Proceedings of IEEE Globecom Conference 2012 (2012, December)

Next generation networks are moving towards the convergence of mobile, fixed and broadcasting services in one standard platform, which requires the co-existence of satellite and terrestrial networks in ... [more ▼]

Next generation networks are moving towards the convergence of mobile, fixed and broadcasting services in one standard platform, which requires the co-existence of satellite and terrestrial networks in the same spectrum. This framework has motivated the concept of cognitive Satellite Communication (SatComs). In this aspect, the problem of exploiting Spectrum Sensing (SS) techniques for a dual polarized fading channel is considered. In this paper, the performance of Energy Detection (ED) technique is evaluated in the context of a co-existence scenario of a satellite and a terrestrial link. Diversity combining techniques such as Equal Gain Combining (EGC) and Selection Combining (SC) are considered to enhance the SS efficiency. Furthermore, analytical expressions for probability of detection (Pd) and probability of false alarm (Pf ) are presented for these techniques in the considered fading channel and the sensing performance is studied through analytical and simulation results. Moreover, the effect of Cross Polar Discrimination (XPD) on the sensing performance is presented and it is shown that SS efficiency improves for low XPD. [less ▲]

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See detailSpectrum Sharing in Hybrid Terrestrial-Satellite Backhaul Networks in the Ka Band
Artiga, Xavier; Vázquez, Miguel Ángel; Pérez-Neira, Ana et al

in European Conference on Networks and Communications (EuCNC), June 2017 (2017, June)

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See detailThe speech and language therapist’s role in differential diagnosis
Deroey, Katrien UL

Bachelor/master dissertation (2004)

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See detailSpeech Based Estimation of Parkinson’s Disease Using Gaussian Processes and Automatic Relevance Determination
Despotovic, Vladimir UL; Skovranek, Tomas; Schommer, Christoph UL

in Neurocomputing (2020), 401

Parkinson’s disease is a progressive neurodegenerative disorder often accompanied by impairment in articulation, phonation, prosody and fluency of speech. In fact, speech impairment is one of the earliest ... [more ▼]

Parkinson’s disease is a progressive neurodegenerative disorder often accompanied by impairment in articulation, phonation, prosody and fluency of speech. In fact, speech impairment is one of the earliest Parkinson’s disease symptoms, and may be used for early diagnosis. We present an experimental study of identification of Parkinson’s disease and assessment of disease progress from speech using Gaussian processes, which is further combined with Automatic Relevance Determination (ARD) for efficient feature selection. Hyperparameters of ARD covariance functions are learned for each individual feature; therefore, can be used for evaluation of their importance. In that way only a small subset of highly relevant acoustic features is selected, leading to models with better performance and lower complexity. The performance of the proposed method was assessed on two datasets: Parkinson’s disease detection dataset, which contains a range of biomedical voice measurements obtained from 31 subjects, 23 of them suffering from Parkinson’s disease and 8 healthy subjects; and Parkinson’s telemonitoring dataset, containing biomedical voice measurements collected from 42 Parkinson’s disease patients for estimation of the disease progress. Gaussian process classification with automatic relevance determination is able to successfully discriminate between Parkinson’s disease patients and healthy controls with 96.92% accuracy, outperforming Support Vector Machines and decision tree ensembles (random forests, boosted and bagged decision trees). The usability of Gaussian processes is further confirmed in regression task for tracking the progress of the disease. [less ▲]

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See detailSpeeding up Collision Search for Byte-Oriented Hash Functions
Khovratovich, Dmitry UL; Biryukov, Alex UL; Nikolic, Ivica UL

in CT-RSA (2009)

We describe a new tool for the search of collisions for hash functions. The tool is applicable when an attack is based on a differential trail, whose probability determines the complexity of the attack ... [more ▼]

We describe a new tool for the search of collisions for hash functions. The tool is applicable when an attack is based on a differential trail, whose probability determines the complexity of the attack. Using the linear algebra methods we show how to organize the search so that many (in some cases — all) trail conditions are always satisfied thus significantly reducing the number of trials and the overall complexity. The method is illustrated with the collision and second preimage attacks on the compression functions based on Rijndael. We show that slow diffusion in the Rijndael (and AES) key schedule allows to run an attack on a version with a 13-round compression function, and the S-boxes do not prevent the attack. We finally propose how to modify the key schedule to resist the attack and provide lower bounds on the complexity of the generic differential attacks for our modification. [less ▲]

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See detailSpeeding-Up Mutation Testing via Data Compression and State Infection
Zhu, Qianqian; Panichella, Annibale UL; Zaidman, Andy

in IEEE International Conference on Software Testing, Verification and Validation Workshops (ICSTW) 2017 (2017, March 13)

Mutation testing is widely considered as a high-end test criterion due to the vast number of mutants it generates. Although many efforts have been made to reduce the computational cost of mutation testing ... [more ▼]

Mutation testing is widely considered as a high-end test criterion due to the vast number of mutants it generates. Although many efforts have been made to reduce the computational cost of mutation testing, its scalability issue remains in practice. In this paper, we introduce a novel method to speed up mutation testing based on state infection information. In addition to filtering out uninfected test executions, we further select a subset of mutants and a subset of test cases to run leveraging data-compression techniques. In particular, we adopt Formal Concept Analysis (FCA) to group similar mutants together and then select test cases to cover these mutants. To evaluate our method, we conducted an experimental study on six open source Java projects. We used EvoSuite to automatically generate test cases and to collect mutation data. The initial results show that our method can reduce the execution time by 83.93% with only 0.257% loss in precision. [less ▲]

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See detailSpeedy assessment of speeded reasoning with the intelligence screening „mini-q“.
Baudson, Tanja Gabriele UL; Kaufmann, M.; Preckel, F. et al

Scientific Conference (2015)

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See detailSpeer und Er. Und Wir? Deutsche Geschichte in gebrochener Erinnerung
Krebs, Stefan UL; Tschacher, Werner

in Geschichte in Wissenschaft und Unterricht (2007), 58(3), 163-173

Warum ist Albert Speer auch heute noch als der „gute Nazi“ im kollektiven Gedächtnis der Bundesrepublik verankert? Ausgehend von der Kontroverse um die Anwesenheit Speers bei der Posener Gauleitertagung ... [more ▼]

Warum ist Albert Speer auch heute noch als der „gute Nazi“ im kollektiven Gedächtnis der Bundesrepublik verankert? Ausgehend von der Kontroverse um die Anwesenheit Speers bei der Posener Gauleitertagung im Oktober 1943 zeichnet der Aufsatz das Ringen geschichtspolitischer Akteure um die Interpretation der NS-Vergangenheit nach. Dabei wird sichtbar, dass in den letzten Jahrzehnten die historische Forschung den Mythos Speer zerstört und ein neues Bild der Nationalsozialisten gezeichnet hat, aber in den Massenmedien weiterhin überkommene Deutungsmuster des „Dritten Reiches“ überdauern. [less ▲]

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