Examining the Role of Privacy in Virtual Migration: The Case of WhatsApp and Threema

WhatsApp is a widely used instant messaging application on smartphones. However, owing to privacy deficiencies in WhatsApp, alternative services that emphasize privacy protection, such as Threema, have emerged. Thus, the question arises whether users would switch from WhatsApp to Threema for privacy reasons, and what the factors are that would affect their switching intention. To answer these questions, we develop a research model examining the role of privacy in virtual migration, using the push-pull-mooring (PPM) migration framework as a theoretical lens. Based on the results of an online survey of 220 German-speaking smartphone users, we found that privacy protection is relevant to users’ switching intention in two ways: as a push effect encouraging users to leave WhatsApp, and as a pull effect attracting users to Threema. However, while our results suggest that peer influence facilitates WhatsApp users’ switching intention, switching costs appear to be a strong barrier

Boosting Vocabulary Learning by Verbal Cueing During Sleep

Reactivating memories during sleep by re-exposure to associated memory cues (e.g., odors or sounds) improves memory consolidation. Here, we tested for the first time whether verbal cueing during sleep can improve vocabulary learning. We cued prior learned Dutch words either during non-rapid eye movement sleep (NonREM) or during active or passive waking. Re-exposure to Dutch words during sleep improved later memory for the German translation of the cued words when compared with uncued words. Recall of uncued words was similar to an additional group receiving no verbal cues during sleep. Furthermore, verbal cueing failed to improve memory during active and passive waking. High-density electroencephalographic recordings revealed that successful verbal cueing during NonREM sleep is associated with a pronounced frontal negativity in event-related potentials, a higher frequency of frontal slow waves as well as a cueing-related increase in right frontal and left parietal oscillatory theta power. Our results indicate that verbal cues presented during NonREM sleep reactivate associated memories, and facilitate later recall of foreign vocabulary without impairing ongoing consolidation processes. Likewise, our oscillatory analysis suggests that both sleep-specific slow waves as well as theta oscillations (typically associated with successful memory encoding during wakefulness) might be involved in strengthening memories by cueing during slee

Relationship between resistivity and specific heat in a canonical non-magnetic heavy fermion alloy system: UPt_5-xAu_x

UPt_(5-x)Au_x alloys form in a single crystal structure, cubic AuBe_5-type, over a wide range of concentrations from x = 0 to at least x = 2.5. All investigated alloys, with an exception for x = 2.5, were non-magnetic. Their electronic specific heat coefficient $\gamma$ varies from about 60 (x = 2) to about 700 mJ/mol K^2 (x = 1). The electrical resistivity for all alloys has a Fermi-liquid-like temperature variation, \rho = \rho_o + AT^2, in the limit of T -> 0 K. The coefficient A is strongly enhanced in the heavy-fermion regime in comparison with normal and transition metals. It changes from about 0.01 (x = 0) to over 2 micro-ohm cm/K^2 (x = 1). A/\gamma^2, which has been postulated to have a universal value for heavy-fermions, varies from about 10^-6 (x = 0, 0.5) to 10^-5 micro-ohm cm (mol K/mJ)^2 (x > 1.1), thus from a value typical of transition metals to that found for some other heavy-fermion metals. This ratio is unaffected, or only weakly affected, by chemical or crystallographic disorder. It correlates with the paramagnetic Curie-Weiss temperature of the high temperature magnetic susceptibility.Comment: 5 pages, 5 eps figures, RevTe

Optimization of Elastic Cloud Brokerage Mechanisms for Future Telecommunication Service Environments

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Cloud computing mechanisms and cloud-based services are currently revolutionizing Web as well as telecommunication service platforms and service offerings. Apart from providing infrastructures, platforms and software as a service, mechanism for dynamic allocation of compute and storage resources on-demand, commonly termed as “elastic cloud computing” account for the most important cloud computing functionalities. Resource elasticity allows not only for efficient internal compute and storage resource consumption, but also, through so called hybrid cloud computing mechanisms, for dynamic utilization of external resources on-demand. This capability is especially useful in order to cost-efficiently cope with peakworkloads, allowing service providers to significantly reduce usually required over-provisioned service infrastructures, allowing for “pay-per-use” cost models. With a steadily growing number of cloud providers and with the proliferation of unified cloud computing interfaces, service providers are given free choice of flexibly selecting and utilizing cloud resources from different cloud providers. Cloud brokering systems allow for dynamic selection and utilization of cloud computing resources based on functional (e.g. QoS, SLA, energy consumption) as well as nonfunctional criteria (e.g. costs). The presented work focuses on enhanced cloud brokering mechanisms for telecommunication service platforms, enabling quality telecommunication service assurance, still optimizing cloud resources consumption, i.e. saving costs and energy. Furthermore this work shows that by combining cloud brokering mechanisms with standardized telecommunication service brokering mechanisms an even greater benefit for telecommunication service providers can be achieved as this enables an even better cost-efficiency since different user segments can seamlessly be served by allocating different cloud resources to them in a policy-driven manner

Facial cues affect the feedback negativity to offers in the ultimatum game

Bei der feedback negativity handelt es sich um eine negative Komponente des ereigniskorrelierten Potentials, die sensibel auf Feedback in Zusammenhang mit negativen Ereignissen oder monetären Verlusten reagiert. Da die feedback negativity zumeist mit Hilfe von experimentellen Paradigmen untersucht wurde, in denen die Folgen einer Handlung mit dem Verhalten der Versuchspersonen übereinstimmten, wurde davon ausgegangen, dass die feedback negativity einen Prozess der Verhaltensüberwachung bzw. des Lernens über kürzlich ausgeführte Handlungen widerspiegle. In verschiedenen Studien konnte jedoch mittlerweile nachgewiesen werden, dass die feedback negativity auch dann hervorgerufen werden kann, wenn Resultate nicht mit vorherigem Verhalten oder vorherigen Entscheidungen übereinstimmen. Diese Ergebnisse führten zu der Vermutung, dass die feedback negativity auch die Evaluation von Erwartungen bezüglich Umweltkontingenzen (zum Beispiel erwartete Zusammenhänge zwischen Belohnungen und Eigenschaften der Stimuli in den entsprechenden Studien) reflektieren könnte. Das Ziel der vorliegende Studie lag nun in der Überprüfung dieser Vermutung, indem versucht wurde die Erwartungen der Versuchspersonen, die die Rolle von Annehmern im Ultimatum Spiel übernahmen, bezüglich Zusammenhängen von Angeboten im Ultimatum Spiel und dem Gesichtsausdruck der jeweiligen Anbietern aufzubauen und die feedback negativity zu evaluieren. Die Anbieter mit denen die Versuchspersonen konfrontiert wurden, zeigten, bevor sie den Versuchspersonen unterschiedlich faire Angebote unterbreiteten, entweder einen freundlichen oder einen verärgerten Gesichtsausdruck. Diese unterschiedlichen Mimiken sollten die Erwartungen der Versuchspersonen in Bezug auf die nachfolgenden Angebote beeinflussen. Nach unfairen Angeboten wurden im Vergleich zu den restlichen Angeboten größerer feedback negativity Amplituden ausgelöst. Des Weiteren lösten freundliche Anbieter, die einen als unfair wahrgenommenen Geldbetrag offerierten, eine größere feedback negativity Amplitude aus, als verärgert aussehende Anbieter, die denselben Betrag anboten. Demzufolge scheinen Erwartungsverletzungen in Bezug auf Kontingenzen im Ultimatum Spiel (freundliche Anbieter unterbreiten unfaire Angebote) zu vergrößerten feedback negativity Amplituden zu führen.The feedback negativity, a component of the event-related brain potential, is elicited by feedback stimuli indicating unfavorable outcomes. The feedback negativity has been regarded to reflect a process of performance monitoring and/or learning about recently executed actions, since it has been primarily investigated using experimental paradigms where outcomes seemed to be contingent upon the behavior of the participants. Recently several studies demonstrated that the feedback negativity can be elicited as well by outcomes that are not contingent on preceding actions or choices. These findings led to the suggestion that the feedback negativity might additionally reflect the evaluation of expectations about environmental contingencies. The present study attempted to test this suggestion by evaluating the feedback negativity while participants‘ expectations about contingencies in the Ultimatum Game, a commonly-used bargaining task, were manipulated. Participants were confronted with proposers, displaying either a smile or an angry face, who provided differential fair offers. The displayed facial expressions were meant to affect expectations about succeeding offers. Larger feedback negativity amplitudes were elicited following unfavorable outcomes, more precisely after unfair and midfair offers, compared to fair offers. Furthermore a happy proposer offering an amount of money perceived as unfair elicited a more pronounced feedback negativity amplitude compared to angry proposers offering the same amount of money. Thus, violated expectations about contingencies in the Ultimatum Game (happy proposers providing unfair offers) led to more pronounced feedback negativity amplitudes

Emotional arousal modulates oscillatory correlates of targeted memory reactivation during NREM, but not REM sleep

Rapid eye movement (REM) sleep is considered to preferentially reprocess emotionally arousing memories. We tested this hypothesis by cueing emotional vs. neutral memories during REM and NREM sleep and wakefulness by presenting associated verbal memory cues after learning. Here we show that cueing during NREM sleep significantly improved memory for emotional pictures, while no cueing benefit was observed during REM sleep. On the oscillatory level, successful memory cueing during NREM sleep resulted in significant increases in theta and spindle oscillations with stronger responses for emotional than neutral memories. In contrast during REM sleep, solely cueing of neutral (but not emotional) memories was associated with increases in theta activity. Our results do not support a preferential role of REM sleep for emotional memories, but rather suggest that emotional arousal modulates memory replay and consolidation processes and their oscillatory correlates during NREM sleep

No effect of targeted memory reactivation during sleep on retention of vocabulary in adolescents

Re-exposure of newly acquired vocabulary during sleep improves later memory recall in healthy adults. The success of targeted memory reactivation (TMR) during sleep presumably depends on the presence of slow oscillations (i.e., EEG activity at a frequency of about 0.75Hz). As slow oscillating activity is at its maximum during adolescence, we hypothesized that TMR is even more beneficial at this developmental stage. In the present study, adolescents aged 11 to 13 learnt Dutch vocabulary in the evening and were tested on recall performance the next morning. Half of the words were presented via loudspeakers during post-learning periods of NREM (Non Rapid Eye Movement) sleep in order to stimulate memory reactivation. Unexpectedly, TMR during sleep did not improve memory on the behavioral level in adolescents. On the oscillatory level, successful reactivation during sleep resulted in the characteristic increase in theta power over frontal brain regions, as reported in adults. However, we observed no increase in spindle power during successful reactivation. Possible factors that may explain the lacking effect of TMR in adolescents in this study such as differences in learning abilities and pre-sleep performance levels are discussed