When Randomization in Collective Tournaments is Profitable for the Principal

In the context of principal-agent theory risk is largely seen as a source that causes inefficiencies and lowers incentives and accordingly is not in the principal’s interest. In this paper I compare two different designs of a collective tournament where output in a team is generated through a particular two-stage production process. I show within a theoretical tournament framework that risk in terms of chance is beneficial from the point of view of a profit maximizing principal who organizes the tournament. Selecting an agent randomly that has to work at the final stage after all agents exerted effort at the first stage helps the principal to overcome a trade-off in incentive provision he faces when selecting the agent who works at the final stage before the tournament starts. This trade-off causes optimal efforts to be lower in a tournament without random selection compared to a tournament with random selection. As the higher efforts overcompensate additional wage costs the principal earns higher expected profits when selecting the agent that has to work at the second stage randomly after the first stage.collective tournament, incentives, randomization, risk

Bewegungstherapeutische Effekte bei Patienten mit gestörter Glukosetoleranz

Eine gezielte bewegungstherapeutische Intervention verbessert den Glukosestoffwechsel, reduziert den Grad der Adipositas und belegt einen antiinflammatorischen Effekt. Ungeklärt ist dabei, in welchem Zeitintervall sich die jeweiligen Risikoparameter Adipositas, Glukosestoffwechsel und chronische Entzündungsreaktionen, in einer 12-monatigen Kontroll-Interventionsstudie bei Patienten mit gestörter Glukosetoleranz (IGT) im Vergleich zu einer Rosiglitazontherapie und einer unbehandelten Kontrollgruppe adaptieren. In der vorliegenden Untersuchung wurden 60 Patienten aus einer Population von 500 Probanden mittels 2-Stunden oralem Glukose Toleranztest (2h-oGTT) als Patienten mit gestörter Glukosetoleranz identifiziert und randomisiert den zwei Therapiearmen, Rosiglitazon- und Bewegungstherapie, sowie einer Kontrollgruppe zugeführt. Es werden dabei die Effekte einer 3-mal wöchentlichen Bewegungstherapie auf den Body Mass Index (BMI), Waist Hip Ratio (WHR), Fasting Plasma Insulin (FPI), Fasting Plasma Glukose (FPG), HbA1c, 2h-oGTT, maximale Sauerstoffaufnahme (VO2max) sowie Interleukin 6 (IL6) und C-reaktives Protein (CrP) nach 1, 6 und 12 Monaten untersucht. Die Bewegungstherapie erzielt nach 1 Monat eine signifikante Verbesserung der Adipositas und des Glukosestoffwechsels. Eine Reduzierung der chronischen Entzündungsreaktion via IL6 konnte nach 12 Monaten erreicht werden. Im vergleichbaren Zeitraum zeigt die Kontrollgruppe keine statistischen Änderungen des BMI, des WHR und der inflammatorischen Parameter. Die Insulinsensitivität verminderte sich in der Kontrollgruppe signifikant innerhalb von 12 Monaten. Unter Applikation von täglich 4 mg Rosiglitazon verbessert sich der Glukosestoffwechsel nach 6 Monaten. Änderungen des Grades der Adipositas und der chronischen Entzündungsreaktion konnten nicht erzielt werden. Die Untersuchungen belegen den hohen Stellenwert der Bewegungstherapie in der Behandlung von IGT-Patienten als Standardtherapieoption. Die Bewegungstherapie sollte mindestens 3-mal wöchentlich als kombiniertes Kraft- und Ausdauertraining bei einer Intensität von 70 - 85 % VO2max und 70 - 85 % 1RM erfolgen.:1 Hintergrund und Ziel der Arbeit 2 Studiendesign und Methoden 3 Ergebnisse 3.1 Einfluss der Bewegungstherapie auf den Gewichtsverlust 3.2 Einfluss der Bewegungstherapie auf den Glukosestoffwechsel 3.3 Einfluss der Bewegungstherapie auf chronische Entzündungsreaktionen 3.4 Einfluss des IL6-Polymorphismus IL6-SNP -174G/C 4 Schlussfolgerung 5 Literaturverzeichnis 6 Publikation Long-term exercise training decreases interleukin-6 (IL6) Serum levels in subjects with impaired glucose tolerance: effect of the -174G/C variant in IL6 gene 7 Zusammenfassung 8 Anhang Erklärung über die eigenständige Abfassung der Arbeit Lebenslauf und wissenschaftlicher Werdegang Danksagun

Fungal Traits Important for Soil Aggregation

Soil structure, the complex arrangement of soil into aggregates and pore spaces, is a key feature of soils and soil biota. Among them, filamentous saprobic fungi have well-documented effects on soil aggregation. However, it is unclear what properties, or traits, determine the overall positive effect of fungi on soil aggregation. To achieve progress, it would be helpful to systematically investigate a broad suite of fungal species for their trait expression and the relation of these traits to soil aggregation. Here, we apply a trait-based approach to a set of 15 traits measured under standardized conditions on 31 fungal strains including Ascomycota, Basidiomycota, and Mucoromycota, all isolated from the same soil. We find large differences among these fungi in their ability to aggregate soil, including neutral to positive effects, and we document large differences in trait expression among strains. We identify biomass density, i.e., the density with which a mycelium grows (positive effects), leucine aminopeptidase activity (negative effects) and phylogeny as important factors explaining differences in soil aggregate formation (SAF) among fungal strains; importantly, growth rate was not among the important traits. Our results point to a typical suite of traits characterizing fungi that are good soil aggregators, and our findings illustrate the power of employing a trait-based approach to unravel biological mechanisms underpinning soil aggregation. Such an approach could now be extended also to other soil biota groups. In an applied context of restoration and agriculture, such trait information can inform management, for example to prioritize practices that favor the expression of more desirable fungal traits

Lack of Disease Specificity Limits the Usefulness of In Vitro Costimulation in HIV- and HCV-Infected Patients

Measurements of antigen-specific T cell responses in chronic diseases are limited by low frequencies of antigen-specific cells in the peripheral blood. Therefore, attempts have been made to add costimulatory molecules such as anti-CD28 or IL-7/IL-15 to ELISPOT assays to increase sensitivity. While this approach has been successful under certain circumstances, results are often inconsistent. To date, there are no comprehensive studies directly comparing the in vitro effects of multiple costimulatory molecules in different disease settings. Therefore, in the present study we tested the effects of IL-7/IL-15, IFN-α, anti-ICOS, and anti-CD28 on antigen-specific T cell responses in patients infected with HCV or HIV versus healthy individuals. Our data show that none of the aforementioned molecules could significantly increase ELISPOT sensitivity, neither in HCV nor in HIV. Moreover, all of them caused false-positive responses to HCV and HIV antigens in healthy individuals. Our results question the broad use of in vitro costimulation

Intensity-Based Camera Setup for Refractometric and Biomolecular Sensing with a Photonic Crystal Microfluidic Chip

Label-free sensing is a promising approach for point-of-care testing devices. Among optical transducers, photonic crystal slabs (PCSs) have positioned themselves as an inexpensive yet versatile platform for label-free biosensing. A spectral resonance shift is observed upon biomolecular binding to the functionalized surface. Commonly, a PCS is read out by a spectrometer. Alternatively, the spectral shift may be translated into an intensity change by tailoring the system response. Intensity-based camera setups (IBCS) are of interest as they mitigate the need for postprocessing, enable spatial sampling, and have moderate hardware requirements. However, they exhibit modest performance compared with spectrometric approaches. Here, we show an increase of the sensitivity and limit of detection (LOD) of an IBCS by employing a sharp-edged cut-off filter to optimize the system response. We report an increase of the LOD from (7.1 ± 1.3) × 10-4 RIU to (3.2 ± 0.7) × 10-5 RIU. We discuss the influence of the region of interest (ROI) size on the achievable LOD. We fabricated a biochip by combining a microfluidic and a PCS and demonstrated autonomous transport. We analyzed the performance via refractive index steps and the biosensing ability via diluted glutathione S-transferase (GST) antibodies (1:250). In addition, we illustrate the speed of detection and demonstrate the advantage of the additional spatial information by detecting streptavidin (2.9 µg/mL). Finally, we present the detection of immunoglobulin G (IgG) from whole blood as a possible basis for point-of-care devices

The Choice of Sports Affects Mental Rotation Performance in Adolescents

This study investigates mental rotation performance of adolescent female dancers and soccer players in object-based and egocentric mental rotation tasks using human body stimuli. 60 young females, 30 soccer players, and 30 dancers (not twosome), completed a chronometric mental rotation task with object-based and egocentric transformation of male and female figures, which were displayed either in front or back view. During their sport-specific activity soccer-players and dancers very often have to adapt their movements to the movement of a partner or opponent, soccer-players especially in front view positions. While for soccer-players reaction time (RT) often is crucial for sporting success, dancers mainly focus on the accuracy of their movements. Therefore, we expect significantly faster RTs for soccer players for front view stimuli but no differences between soccer players and dancers for back view stimuli. The main result was that soccer-players showed a significantly shorter RT than dancers for stimuli presented in front view in object based and egocentric transformation. There was no such difference, when the stimuli were presented in the back view. Contrary to literature we didn't find significantly higher RTs and error rates for stimuli presented in front view compared to back view in general but only for egocentric transformations. The results of this study show that specific sports affect individual aspects of mental rotation performance

Food Intake, Diet Quality and Behavioral Problems in Children: Results from the GINI-plus/LISA-plus Studies

Background/Aims: To assess the association between food intake and diet quality and behavioral problems at the 10-year follow-up of the two population-based birth cohorts of the studies German Infant Nutritional Intervention and `Influences of lifestyle-related factors on the immune system and the development of allergies in childhood'. Methods: Cross-sectional data on food intake over the past year were collected by a parent-reported food frequency questionnaire. Diet quality was based on reference values of food amounts of the optimized mixed diet. Behavioral problems were assessed by a parent-reported Strengths and Difficulties Questionnaire. Relationships between food category intake, diet quality and behavior problems were examined using multivariable regression modeling adjusted for gender, sociodemographic characteristics, body mass index, physical exercise, television viewing/PC use and total energy intake. A total of 3,361 children with complete data were analyzed. Results: Children with increased intake of confectionery had increased odds of having emotional symptoms {[}adjusted odds ratio (ORadj) 1.19, 95% confidence interval (CI) 1.08-1.32] compared to children with low intake. A higher diet quality score was associated with lower likelihood of emotional symptoms (ORadj 0.89, 95% CI 0.80-0.98). The un-adjusted significant relationship between diet quality and hyperactivity/inattention was attenuated by adjusting for several confounders to an ORadj of 0.92 (95% CI 0.82-1.03). Conclusions: Increased consumption of high-sugar products and lower diet quality are associated with a higher likelihood of emotional symptoms in children. Copyright (C) 2012 S. Karger AG, Base