Kryptographiegesetzgebung im Wandel

Zusammenfassung  Im Oktober 2007 trat in Gro?britannien ein Gesetz in Kraft, das es den Polizeibeh?rden erlaubt, die Herausgabe kryptographischer Schlüssel von ihren Nutzern zu verlangen. Dies ist nur eine von zahlreichen Ma?nahmen, die einen globalen Kurswechsel hin zu verst?rkter überwachung und Regulierung von Verschlüsselungsmechanismen belegen. In diesem Beitrag werden die Entwicklungen der Kryptographiegesetzgebung der letzten Jahre und ihr heutiger Stand dokumentiert. Dipl.-Inform. Malte Diehl Doktorand an der Uni Oldenburg, Department für Informatik, Stipendiat der DFG     

Glass-fibre-reinforced composites with enhanced mechanical and electrical properties - Benefits and limitations of a nanoparticle modified matrix

Nanoparticles and especially carbon nanotubes (CNTs) provide a high potential for the modification of polymers. They are very effective fillers regarding mechanical properties, especially toughness. Furthermore, they allow the implication of functional properties, which are connected to their electrical conductivity, into polymeric matrices. In the present paper, different nanoparticles, as fumed silica and carbon black, were used to optimise the epoxy matrix system of a glass-fibre-reinforced composite. Their nanometre-size enables their application as particle-reinforcement in FRPs produced by the resin-transfer-moulding method (RTM), without being filtered by the glass-fibre bundles. Additionally, an electrical field was applied during curing, in order to enhance orientation of the nanofillers in z-direction. The interlaminar shear strengths of the nanoparticle modified composites were significantly improved (+16%) by adding only 0.3 wt.% of CNTs. The interlaminar toughness G_Ic and G_IIc was not affected in a comparable manner. The laminates containing carbon nanotubes exhibited a relatively high electrical conductivity at very low filler contents, which allows the implication of functional properties, such as stress-strain monitoring and damage detection.     

Patterned anvils for high pressure measurements at low temperature

Multiprobe high pressure measurements require electrical leads in the sample chamber. Compared to conventional wire-based techniques, metallic tracks patterned onto the anvil surface improve reliability and ease of use, and enable novel and more demanding measurements under high pressure. We have developed new anvil designs based on sputter-deposited tracks on alumina and moissanite anvils. These anvils allow convenient and reliable measurements of electrical transport properties or of the magnetic susceptibility under hydrostatic conditions, as demonstrated by test measurements on Pb and Ca(3)Ru(2)O(7).     

Digital Frequency Multiplexer for TES Detectors—Path to Flight

Frequency-domain multiplexing has been used for reading out ～1000 detectors on the APEX-SZ and South Pole Telescope receiver for half a decade and produced many high-impact science papers. A?new digital FPGA-based backend reduces the power consumption and system-size by an order of magnitude. This Digital Frequency-domain Multiplexer (DfMUX) was operated successfully in a space-like environment during the stratospheric balloon test-flight of the EBEX polarimeter, saw first light on the POLARBEAR experiment in 2010, and will be deployed for the South Pole Telescope polarimeter and ASTE sub-mm continuum camera. We are presently developing a new generation DfMUX targeting a factor 5 lower power consumption and robustness for satellite platforms. The system will incorporate new technology for identifying and correcting radiation induced errors in the FPGA logic, higher bandwidth to accommodate a multiplexing factor of?64, and Digital Active Nulling (DAN) feedback. DAN linearizes the SQUID system response while dramatically reducing its input impedance.     

Intramyocardial Inflammation after COVID-19 Vaccination: An Endomyocardial Biopsy-Proven Case Series

Myocarditis in response to COVID-19 vaccination has been reported since early 2021. In particular, young male individuals have been identified to exhibit an increased risk of myocardial inflammation following the administration of mRNA-based vaccines. Even though the first epidemiological analyses and numerous case reports investigated potential relationships, endomyocardial biopsy (EMB)-proven cases are limited. Here, we present a comprehensive histopathological analysis of EMBs from 15 patients with reduced ejection fraction (LVEF = 30 (14–39)%) and the clinical suspicion of myocarditis following vaccination with Comirnaty^® (Pfizer-BioNTech) (n = 11), Vaxzevria^® (AstraZenica) (n = 2) and Janssen^® (Johnson & Johnson) (n = 2). Immunohistochemical EMB analyses reveal myocardial inflammation in 14 of 15 patients, with the histopathological diagnosis of active myocarditis according the Dallas criteria (n = 2), severe giant cell myocarditis (n = 2) and inflammatory cardiomyopathy (n = 10). Importantly, infectious causes have been excluded in all patients. The SARS-CoV-2 spike protein has been detected sparsely on cardiomyocytes of nine patients, and differential analysis of inflammatory markers such as CD4⁺ and CD8⁺ T cells suggests that the inflammatory response triggered by the vaccine may be of autoimmunological origin. Although a definitive causal relationship between COVID-19 vaccination and the occurrence of myocardial inflammation cannot be demonstrated in this study, data suggest a temporal connection. The expression of SARS-CoV-2 spike protein within the heart and the dominance of CD4⁺ lymphocytic infiltrates indicate an autoimmunological response to the vaccination.     

Enhancing the efficiency of alternating current driven organic light-emitting devices by optimizing the operation frequency

We report efficient and bright organic light-emitting devices operated by capacitive energy coupling. In this approach, the organic layers are enclosed between sputter-deposited hafnium dioxide layers to prevent charge carrier injection. When a sinusoidal voltage signal is applied to the electrodes, the devices emit bright green light whereas no detectable emission is generated upon application of a constant voltage. The efficiency of the process depends heavily on the frequency of the applied voltage signal. By optimizing the driving scheme, a record luminous efficacy for AC driven OLEDs of 2.7 lm/W at 500 cd/m² is achieved.     

Fostering Creativity in New Product Development through Entrepreneurial Decision Making

Research has emphasized the importance of employees' individual entrepreneurial decision making for innovation. In this context, practised creativity as the ability to perceive and exploit creative opportunities, can be regarded as a crucial requirement for employees in new product development. We discuss the application of decision making logic as an important antecedent of practised creativity in new product development. We survey 219 employees from new product development departments of German product and service firms. Results indicate that the use of entrepreneurial decision making logic positively impacts practised creativity; comparably we find indicators that the use of causal decision making logic negatively influences creativity. The effects significantly depend on the moderating role of uncertainty. The results contribute to the literature of creativity, entrepreneurship and new product development by theoretically and empirically revealing effectuation as antecedent to practised creativity. The results open promising avenues for future research and allow the derivation of valuable guidelines for practitioners. Aligning the new product development process to support employees' entrepreneurial decision making may help generating practised creativity.     

Supporting driver headway choice: The effects of discrete headway feedback when following headway instructions

With specific headway instructions drivers are not able to attain the exact headways as instructed. In this study, the effects of discrete headway feedback (and the direction of headway adjustment) on headway accuracy for drivers carrying out time headway instructions were assessed experimentally. Two groups of each 10 participants (one receiving headway feedback; one control) carried out headway instructions in a driving simulator; increasing and decreasing their headway to a target headway of 2 s at speeds of 50, 80, and 100 km/h. The difference between the instructed and chosen headway was a measure for headway accuracy. The feedback group heard a sound signal at the moment that they crossed the distance of the instructed headway. Unsupported participants showed no significant difference in headway accuracy when increasing or decreasing headways. Discrete headway feedback had varying effects on headway choice accuracy. When participants decreased their headway, feedback led to higher accuracy. When increasing their headway, feedback led to a lower accuracy, compared to no headway feedback. Support did not affect driver's performance in maintaining the chosen headway. The present results suggest that (a) in its current form discrete headway feedback is not sufficient to improve the overall accuracy of chosen headways when carrying out headway instructions; (b) the effect of discrete headway feedback depends on the direction of headway adjustment.     

Flammability of layered silicate epoxy nanocomposites combined with low‐melting inorganic ceepree glass

Tetraphenylphosphonium modified layered silicate epoxy nanocomposite (EP/TPPMMT) combined with low‐melting silicate glass, Ceepree (CP) is investigated by thermal analysis, flammability tests and cone calorimeter at different heat fluxes. Adding CP and TPPMMT does not change the pyrolysis apart from increasing inorganic residue. The total heat evolved (THE) is changed insignificantly, as neither relevant additional carbonaceous charring nor flame inhibition occurs. However, flame retardancy is clearly observed due to an inorganic‐carbonaceous surface protection layer. The peak heat released rate (PHRR) is reduced by around 32–42% when 5 wt% TPPMMT is added, and 51–63% when 10 wt% CP is added. PHRR reduction less than expected is observed when both additives are combined. The reduction is greater than that achieved by using TPPMMT but less than when only CP is used. The morphology of fire residue is investigated by scanning electron microscope on different length scales and turns out to be the key to understanding the efficiency of flame retardancy. The fire residue of EP/CP shows a layered structure, whereas separated columns limit the barrier properties for EP/5%TPPMMT on the micrometer scale. Columns dominating the fire residue structure of EP/5%TPPMMT/10%CP deteriorate the fire retardancy, whereas a more integral structure at the top of the residue causes the improvement over EP/5%TPPMMT. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Performance Effects of Exploratory and Exploitative Innovation Strategies and the Moderating Role of External Innovation Partners

In today's dynamic environment, the involvement of external partners in the innovation process is frequently assumed to be a panacea to cut costs while improving outcomes. In this study, we scrutinize how different collaboration types influence the effects of exploitative and exploratory innovation strategies on new product development (NPD) performance. For our analyses, we draw on a survey comprising a sample of 254 technology-based German firms. Our findings indicate that exploitative strategies are best pursued without comprehensive external collaborations, while the involvement of several partners in a balanced approach is most promising for exploratory strategies. Joint exploration with competitors, in particular, shows the highest effects on NPD performance. The paper discusses the findings and provides several implications for future research.