Systematic trading behaviour and its informational effect: evidence from the OMXH

in Applied Financial Economics (2014), 24(22), 1421-1427

By using signed small trade turnover (SSTT) as a proxy of investors’ systematic trading behaviour and permanent price effect (PPE) as a proxy for informed trading, this article investigates the short-term ... [more ▼]

By using signed small trade turnover (SSTT) as a proxy of investors’ systematic trading behaviour and permanent price effect (PPE) as a proxy for informed trading, this article investigates the short-term outperformance of high SSTT stocks for categories of investors on the NASDAQ OMX Helsinki (OMXH) and whether the outperformance is best understood in the context of investor trading behaviour or informed trading. This study finds that the trading of high SSTT stocks is associated with a lower PPE than the trading of low SSTT stocks, which implies that the trading of high SSTT stocks is less informed than the trading of low SSTT stocks, and that the short-term outperformance of high SSTT stocks relative to low SSTT stocks is best explained within the behavioural finance framework, that is, by investors’ bias towards popular stocks proxied by SSTT, and not within the rational framework, that is, by informed trading proxied by the PPE. These findings are economically and statistically significant for all types of investors. [less ▲]

The systematic variation of task characteristics facilitates the understanding of task difficulty: A cognitive diagnostic modeling approach to complex problem solving

in Psychological Test and Assessment Modeling (2014), 56(1), 83-103

Since the 1960ies, when pioneering research on Item Response Theory (IRT) was published, considerable progress has been made with regard to the psychometrical quality of psychological assessment tools ... [more ▼]

Since the 1960ies, when pioneering research on Item Response Theory (IRT) was published, considerable progress has been made with regard to the psychometrical quality of psychological assessment tools. One recent development building upon IRT is the introduction of Cognitive Diagnostic Modeling (CDM). The major goal of introducing CDM was to develop methods that allow for examining which cognitive processes are involved when a person is working on a specific assessment task. More precisely, CDM enables researchers to investigate whether assumed task characteristics drive item difficulty and, thus, person ability parameters. This may – at least according to the assumption inherent in CDM - allow conclusions about cognitive processes involved in assessment tasks. In this study, out of the numerous CDMs available the Least Square Distance Method (LSDM; Dimitrov, 2012) was applied to investigate psychometrical qualities of an assessment instrument measuring Complex Problem Solving (CPS) skills. For the purpose of the study, two task characteristics essential for mastering CPS tasks were identified ex-ante – degree of connectivity and presence of indirect effects by adding eigendynamics to the task. The study examined whether and how the two hypothesized task characteristics drive item difficulty of two CPS dimensions, knowledge acquisition and knowledge application. The sample consisted of 490 German high school students, who completed the computer-based CPS assessment instrument MicroDYN. The two task characteristics in MicroDYN items were varied systematically. Results obtained in LSDM indicated that the two hypothesized task characteristics, degree of connectivity and introducing indirect effects, drove item difficulty only for knowledge acquisition. Hence, other task characteristics that may determine item difficulty of knowledge application need to be investigated in future studies in order to provide a sound measurement of CPS. [less ▲]

Systematization of threats and requirements for private messaging with untrusted servers. The case of E-mailing and instant messaging

in International Conference on Information Systems Security and Privacy, Malta 25-27 February 2020 (2020, February)

Modern email and instant messaging applications often offer private communications. In doing so, they share common concerns about how security and privacy can be compromised, how they should face similar ... [more ▼]

Modern email and instant messaging applications often offer private communications. In doing so, they share common concerns about how security and privacy can be compromised, how they should face similar threats, and how to comply with comparable system requirements. Assuming a scenario where servers may not be trusted, we review and analyze a list of threats specifically against message delivering, archiving, and contact synchronization. We also describe a list of requirements intended for whom undertakes the task of implementing secure and private messaging. The cryptographic solutions available to mitigate the threats and to comply with the requirements may differ, as the two applications are built on different assumptions and technologies. [less ▲]

Le système juridictionnel de l’Union comme garantie de l’Etat de droit dans la jurisprudence récente de la CJUE

in Revue du Droit de l'Union Européenne (2019), (4), 153-168

La jurisprudence récente de la Cour de justice suggère que la fonction du système juridictionnel de l’Union, composé des juridictions nationales et européennes stricto sensu, n’est pas seulement de ... [more ▼]

La jurisprudence récente de la Cour de justice suggère que la fonction du système juridictionnel de l’Union, composé des juridictions nationales et européennes stricto sensu, n’est pas seulement de garantir le contenu matériel de l’Etat de droit. Les principes régissant ce système et ses mécanismes constituent en effet autant de composantes du contenu de l’Etat de droit et font du système juridictionnel une garantie à part entière de cette valeur fondatrice de l’Union. D’un point de vue procédural, la fonction nouvelle du système juridictionnel s’exprime par les obligations incombant aux Etats membres et par l’office européen du juge national, dont la pratique a transformé, dans un esprit de loyauté juridictionnelle et de volontarisme, les mécanismes du renvoi préjudiciel et du mandat d’arrêt européen en garanties systémiques de l’Etat de droit. La présente contribution propose une modélisation nouvelle de l’Union qui permet de visualiser le rapprochement du contenu systémique de la protection juridictionnelle et du principe européen de légalité mais aussi la suprématie du principe de loyauté qui non seulement affecte le principe de légalité mais fait aussi émerger des principes fonctionnels dérivés tels que la primauté et la confiance mutuelle. [less ▲]

Un système plurilingue peut-il être efficace?

in Cahiers du Service de Pédagogie Expérimentale (SPE) (2003, September), 15(16), 157-164

Le système scolaire luxembourgeois: Un système scolaire scolaire peu efficace malgré ou à cause de son caractère multilingue?

in Cahiers du Service de Pédagogie Expérimentale (SPE) (2003), 15/16(4), 516-532

Systèmes de numération en base rationnelle

Presentation (2008, October)

Systemic network analysis identifies XIAP and IkappaBalpha as potential drug targets in TRAIL resistant BRAF mutated melanoma.

in NPJ systems biology and applications (2018), 4

Metastatic melanoma remains a life-threatening disease because most tumors develop resistance to targeted kinase inhibitors thereby regaining tumorigenic capacity. We show the 2nd generation hexavalent ... [more ▼]

Metastatic melanoma remains a life-threatening disease because most tumors develop resistance to targeted kinase inhibitors thereby regaining tumorigenic capacity. We show the 2nd generation hexavalent TRAIL receptor-targeted agonist IZI1551 to induce pronounced apoptotic cell death in mutBRAF melanoma cells. Aiming to identify molecular changes that may confer IZI1551 resistance we combined Dynamic Bayesian Network modelling with a sophisticated regularization strategy resulting in sparse and context-sensitive networks and show the performance of this strategy in the detection of cell line-specific deregulations of a signalling network. Comparing IZI1551-sensitive to IZI1551-resistant melanoma cells the model accurately and correctly predicted activation of NFkappaB in concert with upregulation of the anti-apoptotic protein XIAP as the key mediator of IZI1551 resistance. Thus, the incorporation of multiple regularization functions in logical network optimization may provide a promising avenue to assess the effects of drug combinations and to identify responders to selected combination therapies. [less ▲]

A systemic transcriptome analysis reveals the regulation of neural stem cell maintenance by an E2F1-miRNA feedback loop.

in Nucleic Acids Research (2013), 41(6), 3699-712

Stem cell fate decisions are controlled by a molecular network in which transcription factors and miRNAs are of key importance. To systemically investigate their impact on neural stem cell (NSC ... [more ▼]

Stem cell fate decisions are controlled by a molecular network in which transcription factors and miRNAs are of key importance. To systemically investigate their impact on neural stem cell (NSC) maintenance and neuronal commitment, we performed a high-throughput mRNA and miRNA profiling and isolated functional interaction networks of involved mechanisms. Thereby, we identified an E2F1-miRNA feedback loop as important regulator of NSC fate decisions. Although E2F1 supports NSC proliferation and represses transcription of miRNAs from the miR-17 approximately 92 and miR-106a approximately 363 clusters, these miRNAs are transiently up-regulated at early stages of neuronal differentiation. In these early committed cells, increased miRNAs expression levels directly repress E2F1 mRNA levels and inhibit cellular proliferation. In mice, we demonstrated that these miRNAs are expressed in the neurogenic areas and that E2F1 inhibition represses NSC proliferation. The here presented data suggest a novel interaction mechanism between E2F1 and miR-17 approximately 92 / miR-106a approximately 363 miRNAs in controlling NSC proliferation and neuronal differentiation. [less ▲]

Systemisches und räumliches Denken in der geographischen Bildung. Erste Ergebnisse zur Überprüfung eines Modells der Geographischen Systemkompetenz

in Hüttermann, A.; Kirchner, P.; Schuler, S. (Eds.) et al Räumliche Orientierung: Räumliche Orientierung, Karten und Geoinformation im Unterricht (2012)