University of Cologne

About: University of Cologne is a education organization based out in Cologne, Germany. It is known for research contribution in the topics: Population & Transplantation. The organization has 32050 authors who have published 66350 publications receiving 2210092 citations. The organization is also known as: Universität zu Köln & Universitatis Coloniensis.

Avatar-Mediated Networking: Increasing Social Presence and Interpersonal Trust in Net-Based Collaborations

Abstract: This study analyzes the influence of avatars on social presence, interpersonal trust, perceived communication quality, nonverbal behavior, and visual attention in Net-based collaborations using a comparative approach. A real-time communication window including a special avatar interface was integrated into a shared collaborative workspace. Communication modes under investigation were text chat, audio, audio-video, and avatar. Significant differences were found between text chat and all other communication modalities in perceived intimateness, co-presence, and emotionally-based trust. Microanalyses of nonverbal activity and visual attention point to similarities between video and avatar modes, both showing higher levels of exposure to the virtual other and visual attention, in particular in the initial phase of interaction as compared to text and audio.

Induction of T and B cell immunity by anti-idiotypic antibody.

Abstract: A small dose of the IgG1 fraction of anti-idiotypic antibody (aId1) raised in guinea pigs against a strain A/J antibody specific for streptococcal Group A carbohydrate sensitizes A/J mice against Group A streptococci. This is opposed to the previously established suppressive function of anti-idiotypic antibody of the IgG2 class (aId2). Correspondingly, aId1 but not aId2 is eliminated from the circulation in the way typical of an immunogenic molecule. However, the stimulatory component in the IgG1 fraction is not necessarily itself IgG1 antibody. Sensitization occurs in both B and helper T lymphocytes and is specific for Group A streptococci. In the B cell compartment sensitization is restricted to precursor cells expressing the idiotype. The concomitant activation of T helper cells therefore suggests that these cells make use of receptors with a similar or identical idiotype. Efficient sensitization by aId1 of both T and B cells is also demonstrated in strain C57L/J mice which upon immunization with Group A streptococci express a partially cross-reacting idiotype as a minor component. When such animals were primed with aId1, essentially all of the anti-carbohydrate antibody carried the partially cross-reacting idiotype.

Efficacy and Tolerability of Evolocumab vs Ezetimibe in Patients With Muscle-Related Statin Intolerance: The GAUSS-3 Randomized Clinical Trial

Abstract: Importance Muscle-related statin intolerance is reported by 5% to 20% of patients. Objective To identify patients with muscle symptoms confirmed by statin rechallenge and compare lipid-lowering efficacy for 2 nonstatin therapies, ezetimibe and evolocumab. Design, Setting, and Participants Two-stage randomized clinical trial including 511 adult patients with uncontrolled low-density lipoprotein cholesterol (LDL-C) levels and history of intolerance to 2 or more statins enrolled in 2013 and 2014 globally. Phase A used a 24-week crossover procedure with atorvastatin or placebo to identify patients having symptoms only with atorvastatin but not placebo. In phase B, after a 2-week washout, patients were randomized to ezetimibe or evolocumab for 24 weeks. Interventions Phase A: atorvastatin (20 mg) vs placebo. Phase B: randomization 2:1 to subcutaneous evolocumab (420 mg monthly) or oral ezetimibe (10 mg daily). Main Outcome and Measures Coprimary end points were the mean percent change in LDL-C level from baseline to the mean of weeks 22 and 24 levels and from baseline to week 24 levels. Results Of the 491 patients who entered phase A (mean age, 60.7 [SD, 10.2] years; 246 women [50.1%]; 170 with coronary heart disease [34.6%]; entry mean LDL-C level, 212.3 [SD, 67.9] mg/dL), muscle symptoms occurred in 209 of 491 (42.6%) while taking atorvastatin but not while taking placebo. Of these, 199 entered phase B, along with 19 who proceeded directly to phase B for elevated creatine kinase (N = 218, with 73 randomized to ezetimibe and 145 to evolocumab; entry mean LDL-C level, 219.9 [SD, 72] mg/dL). For the mean of weeks 22 and 24, LDL-C level with ezetimibe was 183.0 mg/dL; mean percent LDL-C change, −16.7% (95% CI, −20.5% to −12.9%), absolute change, −31.0 mg/dL and with evolocumab was 103.6 mg/dL; mean percent change, −54.5% (95% CI, −57.2% to −51.8%); absolute change, −106.8 mg/dL ( P P P = .17). Active study drug was stopped for muscle symptoms in 5 of 73 ezetimibe-treated patients (6.8%) and 1 of 145 evolocumab-treated patients (0.7%). Conclusions and Relevance Among patients with statin intolerance related to muscle-related adverse effects, the use of evolocumab compared with ezetimibe resulted in a significantly greater reduction in LDL-C levels after 24 weeks. Further studies are needed to assess long-term efficacy and safety. Trial Registration clinicaltrials.gov Identifier:NCT01984424

Two-lane traffic rules for cellular automata: A systematic approach

Abstract: Microscopic modeling of multi-lane traffic is usually done by applying heuristic lane changing rules, and often with unsatisfying results. Recently, a cellular automaton model for two-lane traffic was able to overcome some of these problems and to produce a correct density inversion at densities somewhat below the maximum flow density. In this paper, we summarize different approaches to lane changing and their results, and propose a general scheme, according to which realistic lane changing rules can be developed. We test this scheme by applying it to several different lane changing rules, which, in spite of their differences, generate similar and realistic results. We thus conclude that, for producing realistic results, the logical structure of the lane changing rules, as proposed here, is at least as important as the microscopic details of the rules.

Stellar Dynamics in the Central Arcsecond of Our Galaxy

Abstract: With 10 years of high-resolution imaging data now available on the stellar cluster in the Galactic center, we present proper motions for more than 40 stars at projected distances ≤12 from Sagittarius A* (Sgr A*). We find evidence on a ≥2 σ level for radial anisotropy of the cluster of stars within 1'' of Sgr A*. For a brightness limit of K ~ 15.5, we find no evidence for a stationary source at the position of Sgr A* or for a source at this position that would be variable on a timescale of at least several hours to days. On timescales of seconds to tens of minutes, we find no variability at the Sgr A* position on brightness levels K ≤ 13.5. We confirm/find accelerated motion for six stars, with four stars having passed the pericenter of their orbits during the observed time span. We calculated/constrained the orbital parameters of these stars. All orbits have moderate to high eccentricities. We discuss the possible bias in detecting preferentially orbits with high eccentricities and find that measured values of e > 0.9 might be detected by about a factor of 1.5-2 more frequently. We find that the center of acceleration for all the orbits coincides with the radio position of Sgr A*. From the orbit of the star S2, the currently most tightly constrained one, we determine the mass of Sgr A* to be × 106 M☉ and its position to 2.0 ± 2.4 mas east and 2.7 ± 4.5 mas south of the nominal radio position. The mass estimate for the central dark mass from the orbit of S2 is fully consistent with the mass estimate of × 106 M☉ obtained from stellar proper motions within 12 of Sgr A* using a Leonard-Merritt mass estimator. We find that radio astronomical observations of the proper motion of Sgr A*, in combination with its intrinsic source size, place at the moment the tightest constraints on the mass density of Sgr A*, which must exceed ρ > 3 × 1019 M☉ pc-3.