Nimodipin versus Magnesium als Vasospasmusprophylaxe bei der Behandlung von Patienten mit aneurysmatischer Subarachnoidalblutung

Abstract: Objective: The prophylactic use of nimodipine in patients with aneurysmal subarachnoid hemorrhage (SAH) reduces the risk of ischemic brain damage, however its efficacy appears rather moderate. The question arises whether other types of calcium antagonists offer better protection. Magnesium, nature's physiologic calcium antagonist, is neuroprotective in animal models, promotes dilatation of cerebral arteries, and has an established safety profile. The aim of the current study is to evaluate the efficacy of magnesium versus nimodipine to prevent delayed ischemic deficits after aneurysmal SAH. Methods: 113 patients with aneurysmal SAH were enrolled in the study and randomized to receive either magnesium sulfate (loading 10 mg/kg followed by 30 mg/kg/d) or nimodipine (48 mg/d) intravenously until postoperative day 7. Primary parameters were blood flow velocity as determined by daily transcranial Doppler (TCD), incidence of vasospasm and infarction, and outcome at discharge. Results: 104 patients met the study requirements. In the magnesium group (N=53) 8 patients (15%) developed symptomatic and 20 patients (38%) asymptomatic vasospasm according to TCD criteria compared to 14 (27%) and 17 (33%) patients in nimodipine the group (N=51). If symptomatic vasospasm occurred, 75% of the magnesium-treated versus 50% of the nimodipine-treated patients developed cerebral infarction resulting in fatal outcome in 37% and 14%, respectively. Overall there was no difference in outcome between groups. Conclusion: The observed trend towards a lesser incidence of symptomatic vasospasm in magnesium-treated patients and the lesser incidence of fatal outcome from symptomatic vasospasm in nimodipine-treated patients make future studies on the combined administration of magnesium and nimodipine appear promising

Zwischen Wien, Versailles und Berlin. Handlungsspielräume und Strukturen badischer Diplomatie im Ancien Régime

Die Dissertation analysiert die Strukturen und die Funktionsweise eines kleinstaatlichen Corps diplomatique am Beispiel der Markgrafschaft Baden-Durlach. Dabei werden die Möglichkeiten und Grenzen der Reichs- und Außenpolitik vom Ende des Spanischen Erbfolgekrieges 1714 und dem Tod Ludwigs XIV. 1715 bis zur Wiedervereinigung mit der katholischen Markgrafschaft Baden-Baden 1771 untersucht. Der Schwerpunkt bildet die protestantische Linie Baden-Durlach. Im Ancien Régime verfügten deutsche Einzelstaaten über das Recht, politische Beziehungen auf internationaler Ebene zu unterhalten und mit Gesandten vor Ort vertreten zu sein. Durch die Lage an der deutsch-französischen Grenze musste der Karlsruher Hof stets auf ein gutes Verhältnis zum Kaiser und zum König von Frankreich bedacht sein, so dass sich die Arbeit mit den Optionen kleinstaatlicher Politik im 18. Jahrhundert befasst. Auch das im Zug der friderizianischen Außenpolitik zur Großmacht avancierte protestantische Preußen spielte für den Karlsruher Hof seit dem Siebenjährigen Krieg eine immer wichtigere Rolle

The Digital Transformation of the News Media Business – Paid Content and Entrepreneurship in Digital Journalism

The digital transformation of the news business continues to agitate publishers. Concerned about declining sales in the print segment, legacy outlets, local news companies and freelance journalists alike search for ways to monetize digital journalism properly. At first glance, digital journalism and its monetisation as paid content seem a promising effort. The digitisation of the news business enabled distribution at a marginal cost of almost zero while giving journalists access to new research technologies and lowering the cost of entry for smaller companies. However, while digital journalism enjoys broad popularity and use, online news are gaining few paying customers. Furthermore, online news compete within a larger digital media complex, comprising movies, games, and social media. After 25 years of experimentation, the digital future of journalism is still heavily debated in media management. Concerning the reconstitution as a digital medium, this research examines conditions of success and obstacles for the digital news media business to be successful as a business venture. Therefore, the research question reads What factors enable the viability and entrepreneurial success of the news media business in light of the consequences of digital transformation? The overarching research question is considered from two angles: The first angle concerns the demand side by looking at the antecedents of the audience's willingness to pay for paid content. The second angle focuses on the supply side and therefore examines antecedents of success in the context of digital journalistic start-ups and founders. In four studies, this thesis develops an analysis of the online news business with a local focus on the German news market. For this purpose, a variety of methods ranging from qualitative work and literature review to empirical research employing path analysis and predictive analytics are applied. Theoretically, digital transformation, free mentality and other peculiarities of information goods inform the frame of this work. Thus, this research aims at contributing to a financially sustainable news media business

Privately Waiting – A Usability Analysis of the Tor Anonymity Network

As the Internet is increasingly absorbing information from the real world it becomes more important to prevent unauthorized collection and abuse of personalized information. At the same time, democratic societies should establish an environment helping not only their own people but also people who face repressive censorship to access public information without being identified or traced. Internet anonymization tools such as Tor offer functionalities to meet this demand. In practice, anonymization of Internet access can only be achieved by accepting higher latency, i.e., a longer waiting time before a Web site is displayed in the browser, and therefore reducing its usability significantly. Since many users may not be willing to accept this loss of usability, they may refrain from or stop using Tor – at the same time decreasing the anonymity of other users, which depends on shared resources in the Tor user community. In this paper1, we quantify the loss of usability by measuring the additional latency of the Tor software and combine our measurements with metrics of the existing Web usability and performance literature. Our findings indicate that there is still a major usability gap induced by Tor, leading to its possible disuse accompanied by a higher risk exposure of Internet users

The Impact of National Culture on Mobile Commerce Adoption and Usage Intensity

The usage of mobile commerce increases around the world. However, little is known about why adoption and usage of mobile commerce services differ across countries. We address this question by analyzing the impact of national culture on mobile commerce adoption and usage intensity. Using a dataset that comprises individual consumer survey data from 43 countries across six continents and country-level data on Hofstede’s six cultural dimensions, we study cross-cultural adoption and usage patterns pertaining three mobile commerce services, i.e. mobile banking, mobile shopping and mobile payment. Our results show that adoption and usage intensity are indeed affected by different cultural dimensions. Specifically, the adoption of mobile commerce services is negatively influenced by a country’s level of uncertainty avoidance, while consumers’ usage intensity is driven by indulgence. This implies that providers of mobile commerce services need to tailor their market entry and market cultivation strategies accounting for each country’s specific culture

The Impact of National Culture on Mobile Commerce Adoption and Usage Intensity

The usage of mobile commerce increases around the world. However, little is known about why adoption and usage of mobile commerce services differ across countries. We address this question by analyzing the impact of national culture on mobile commerce adoption and usage intensity. Using a dataset that comprises individual consumer survey data from 43 countries across six continents and country-level data on Hofstede’s six cultural dimensions, we study cross-cultural adoption and usage patterns pertaining three mobile commerce services, i.e. mobile banking, mobile shopping and mobile payment. Our results show that adoption and usage intensity are indeed affected by different cultural dimensions. Specifically, the adoption of mobile commerce services is negatively influenced by a country’s level of uncertainty avoidance, while consumers’ usage intensity is driven by indulgence. This implies that providers of mobile commerce services need to tailor their market entry and market cultivation strategies accounting for each country’s specific culture

Coherent phonon-magnon interactions detected by micro-focused Brillouin light scattering spectroscopy

We investigated the interaction of surface acoustic waves and spin waves with spatial resolution by micro-focused Brillouin light scattering spectroscopy in a Co$_{40}$Fe$_{40}$B$_{20}$ ferromagnetic layer on a LiNbO$_{3}$-piezoelectric substrate. We experimentally demonstrate that the magnetoelastic excitation of magnons by phonons is coherent by studying the interfering BLS-signals of the phonons and magnons during their conversion process.We find a pronounced spatial dependence of the phonon annihilation and magnon excitation which we map as a function of the magnetic field. The coupling efficiency of the surface acoustic waves (SAWs) and the spin waves (SWs) is characterized by a magnetic field dependent decay of the SAWs amplitude