University of Mannheim

About: University of Mannheim is a education organization based out in Mannheim, Germany. It is known for research contribution in the topics: Population & European union. The organization has 4448 authors who have published 12918 publications receiving 446557 citations. The organization is also known as: Uni Mannheim & UMA.

The economic benefits of public infrastructure

Abstract: The impact of the provision of public infrastructure on private economic activity is examined. Using a flexible functional form of a cost function with public infrastructure as an additional extern...

A randomized multi-center phase II trial of the angiogenesis inhibitor Cilengitide (EMD 121974) and gemcitabine compared with gemcitabine alone in advanced unresectable pancreatic cancer

Abstract: Anti-angiogenic treatment is believed to have at least cystostatic effects in highly vascularized tumours like pancreatic cancer. In this study, the treatment effects of the angiogenesis inhibitor Cilengitide and gemcitabine were compared with gemcitabine alone in patients with advanced unresectable pancreatic cancer. A multi-national, open-label, controlled, randomized, parallel-group, phase II pilot study was conducted in 20 centers in 7 countries. Cilengitide was administered at 600 mg/m2 twice weekly for 4 weeks per cycle and gemcitabine at 1000 mg/m2 for 3 weeks followed by a week of rest per cycle. The planned treatment period was 6 four-week cycles. The primary endpoint of the study was overall survival and the secondary endpoints were progression-free survival (PFS), response rate, quality of life (QoL), effects on biological markers of disease (CA 19.9) and angiogenesis (vascular endothelial growth factor and basic fibroblast growth factor), and safety. An ancillary study investigated the pharmacokinetics of both drugs in a subset of patients. Eighty-nine patients were randomized. The median overall survival was 6.7 months for Cilengitide and gemcitabine and 7.7 months for gemcitabine alone. The median PFS times were 3.6 months and 3.8 months, respectively. The overall response rates were 17% and 14%, and the tumor growth control rates were 54% and 56%, respectively. Changes in the levels of CA 19.9 went in line with the clinical course of the disease, but no apparent relationships were seen with the biological markers of angiogenesis. QoL and safety evaluations were comparable between treatment groups. Pharmacokinetic studies showed no influence of gemcitabine on the pharmacokinetic parameters of Cilengitide and vice versa. There were no clinically important differences observed regarding efficacy, safety and QoL between the groups. The observations lay in the range of other clinical studies in this setting. The combination regimen was well tolerated with no adverse effects on the safety, tolerability and pharmacokinetics of either agent.

Seminonparametric Estimation of Binary-Choice Models With an Application to Labor-Force Participation

Abstract: We adapt the estimation method proposed by Gallant and Nychka to binary-choice models. We present Monte Carlo and asymptotic comparisons with the probit estimator and discuss optimization algorithms, choice of starting values, and strategies for choosing the number of parameters used in approximating the density. Seminonparametric estimation is almost as efficient as probit estimation in normal samples and performs better in nonnormal samples. The estimation of a participation model with 3,658 observations and 21 explanatory variables demonstrates the practicability of this approach on personal computers.

Online communities: a longitudinal analysis of communication activities

Abstract: Online communities (OCs) are seen as an important stimulus to electronic business. However, surprisingly little is known about how the communication activity of their users develops and changes over time. A longitudinal study bears the potential to better elaborate the enabling and inhibiting factors of the users' communication activity in OCs. To explore these phenomena, we aim to develop a conceptual framework that serves as a foundation to guide an explorative data analysis of real OCs. The notions of common ground, information overload, interactivity and social loafing will be used to explain the communication activity of the users in online communities. The empirically explored framework will help organizations to support the development of OCs and utilize them in an economically successful way. Based on a literature review we develop a first conceptual framework. Then, we apply it to describe the development of the communication activity and its determinants in an OC hosted by a German financial service provider. The study examines over 33,000 participants and 1.03 million messages over a period of 3 years. We find a strong effect of external factors on the size of this OC. The size of the OC shows no direct influence on the communication activity of the users. But, in reaction to the increasing information load, communication strategies change and herewith influence the communication activity. The heterogeneity of the users' activity is growing over time and a small minority of users writes more and more of the postings.

Facial mimicry and the mirror neuron system: simultaneous acquisition of facial electromyography and functional magnetic resonance imaging.

Abstract: Numerous studies have shown that humans automatically react with congruent facial reactions, i.e. facial mimicry, when seeing a vis-a-vis’ facial expressions. The current experiment is the first investigating the neuronal structures responsible for differences in the occurrence of such facial mimicry reactions by simultaneously measuring BOLD and facial EMG in an MRI scanner. Therefore, 20 female students viewed emotional facial expressions (happy, sad, and angry) of male and female avatar characters. During Differentiation presentation, the BOLD signal as well as M. zygomaticus major and M. corrugator supercilii activity were recorded simultaneously. Results show prototypical patterns of facial mimicry after correction for MR-related artifacts: enhanced M. zygomaticus major activity in response to happy and enhanced M. corrugator supercilii activity in response to sad and angry expressions. Regression analyses show that these congruent facial reactions correlate significantly with activations in the IFG, SMA and cerebellum. Stronger zygomaticus reactions to happy faces were further associated to increased activities in the caudate, MTG and PCC. Corrugator reactions to angry expressions were further correlated with the hippocampus, insula and STS. Results are discussed in relation to core and extended models of the mirror neuron system.