Über Ceratiten

Gelesen in der Akademie der Wissenschaften am 20. Januar 184

Colonel Blotto games with a head start

This paper studies Colonel Blotto games with two battlefields where one player has a head start in the form of additional troops on one of the battlefields. Such games arise naturally in marketing, electoral competition, and military conflict. Sion and Wolfe (1957) have shown that, if the strategy space is continuous, a mixed-strategy Nash equilibrium need not exist. Therefore, we consider a finite approximation. Using the iterated elimination of (weakly) dominated strategies, we identify an equilibrium for all parameter constellations and discuss its uniqueness properties. In equilibrium, resource decisions are typically not uniform but tend to concern units that roughly correspond in size to multiples of the head start. Moreover, competition takes the form of a hide-and-seek game, where the favorite tries to outguess the number of units that the underdog commits to the balanced battlefield. Somewhat unexpectedly, equilibrium payoffs of finite approximations of the Sion-Wolfe game accumulate around precisely three values. We also discuss the relation to the model with heterogeneous budgets but no head start

Künftige Wettbewerbsfähigkeit der Milchproduktion im Berggebiet Österreichs und der Schweiz

The mountain areas of Austria and Switzerland are important locations for dairy farming. Owing to natural conditions, the milk in these areas is produced at a considerably higher cost. Nevertheless, structural change in the mountain areas of both countries proceeded at a lower pace than in the plain areas. Milk production in the mountain area of Austria was appreciably expanded. This paper presents a number of attempts to explain these regional shifts, analysing the competitiveness of the farms, as well as the alternatives outside of milk production in the mountain and plain areas of Austria and Switzerland. In addition, we investigate whether milk production in these regions is also capable of holding its ground under future conditions. The on-average lower opportunity costs for land and labour in mountain areas are largely responsible for the high perseverance of dairy farmers in these regions. Common to both countries, however, is the fact that the competitiveness of farms in mountain areas can only be guaranteed by high direct payments. The extent of these direct payments is appreciably higher in Switzerland than in Austria, owing to the expected alignment of Swiss and EU milk prices, and the higher wage level in Switzerland. The high national economic importance of mountain milk production with regard to tourism and decentralised settlement explains the broad social acceptance of these payments, which should be less affected by cutbacks than other agricultural subsidies.competitiveness, milk production, mountain areas, opportunity costs, Austria, Switzerland, Agricultural and Food Policy, Livestock Production/Industries, Farm Management,

Achromatic, planar Fresnel-Reflector for a Single-beam Magneto-optical Trap

We present a novel achromatic, planar, periodic mirror structure for single-beam magneto-optical trapping and demonstrate its use in first- and second-stage cooling and trapping for different isotopes of strontium. We refer to it as Fresnel MOT as the structure is inspired by Fresnel lenses. By design, it avoids many of the problems that arise for multi-color cooling using planar structures based on diffraction gratings, which have been the dominant planar structures to be used for single-beam trapping thus far. In addition to a complex design process and cost-intensive fabrication, diffraction gratings suffer from their inherent chromaticity, which causes different axial displacements of trap volumes for the different wavelengths and necessitates tradeoffs in their diffraction properties and achievable trap depths. In contrast, the Fresnel reflector structure presented here is a versatile, easy-to-manufacture device that combines achromatic beam steering with the advantages of a planar architecture. It enables miniaturizing trapping systems for alkaline-earth-like atoms with multiple cooling transitions as well as multi-species trapping in the ideal tetrahedral configuration and within the same volume above the structure. Our design presents a novel approach for the miniaturization of cold-atom systems based on single-beam MOTs and enables the widespread adoption of these systems.Comment: 7 pages, 6 figure

Die betriebliche Integration leistungsgewandelter Mitarbeiter

Die Integration leistungsgewandelter Mitarbeiter wird vor allem auf Grund des demografischen Wandels in der Arbeitswelt ein Problem für Unternehmen. Nach Begriffsbestimmungen und der Kennzeichnung der Gruppe Leistungsgewandelter erfolgt die Einordnung des Problems in verschiedene Managementkonzepte, d. h. in das Personal-, Gesundheits-, Diversity Management und Disability Management. Sodann werden das Integrations-, Separations-, Flexibilisierungs- und Insourcing-Outsourcing-Modell zur betrieblichen Eingliederung Leistungsgewandelter diskutiert. Es erfolgt überwiegend am Beispiel des Projekts "Work2Work". Schließlich werden aus diesem Projekt Folgerungen für weitere Unternehmen abgeleitet.The integration of employees with changing capabilities and productivity levels is becoming an issue for companies against the background of demographic changes in the workplace. After defining the term and identifying the group of employees with changing capabilities and productivity levels, the issue is integrated in management concepts i.e. in human resources, health, diversity and disability management. There follows a discussion on the integration of employees with changing capabilities and productivity levels using the models for integration, separation, flexibilisation and in-sourcing/out-sourcing. The discussion is based largely on the "Work2Work" project. Conclusions are drawn from this project for other companies

Kundenakzeptanz von Bluetooth-Beacons im Lebensmittelhandel

Die Nutzung des Internets hat zu einem veränderten Kaufverhalten der Gesellschaft geführt, was wiederum Auswirkungen auf den stationären Einzelhandel hat. Da die Anzahl an Smartphone-Nutzern ebenfalls kontinuierlich steigt, werden mobile Anwendungen immer wichtiger. Durch den Einsatz von Bluetooth-Beacons – kleinen, beliebig platzierbaren Funksendern, dessen Signale von einer entsprechenden App verarbeitet werden können – kann der Einkauf sowohl erleichtert als auch erlebnisreicher gestaltet werden. Der Gebrauch von Beacons in Deutschland ist weniger verbreitet und erforscht. Pilotprojekte stützen sich lediglich auf Nutzungsdaten und Reaktionszeiten, jedoch nicht auf Kundenmeinungen. Diese Arbeit untersucht Nutzungsmöglichkeiten und Kundenakzeptanz von auf Beacons basierenden Konzepten im Einzelhandel mittels einer Online-Kundenumfrage

Characterization of a CCD array for Bragg spectroscopy

The average pixel distance as well as the relative orientation of an array of 6 CCD detectors have been measured with accuracies of about 0.5 nm and 50 $\mu$rad, respectively. Such a precision satisfies the needs of modern crystal spectroscopy experiments in the field of exotic atoms and highly charged ions. Two different measurements have been performed by illuminating masks in front of the detector array by remote sources of radiation. In one case, an aluminum mask was irradiated with X-rays and in a second attempt, a nanometric quartz wafer was illuminated by a light bulb. Both methods gave consistent results with a smaller error for the optical method. In addition, the thermal expansion of the CCD detectors was characterized between -105 C and -40 C.Comment: Submitted to Review of Scientific Instrument

Extended Trochanteric Osteotomy with Intermediate Resection Arthroplasty Is Safe for Use in Two-Stage Revision Total Hip Arthroplasty for Infection

Background: This study sought to compare the results of two-stage revision total hip arthroplasty (THA) for periprosthetic infection (PJI) in patients with and without the use of an extended trochanteric osteotomy (ETO) for removal of a well-fixed femoral stem or cement. Methods: Thirty-two patients who had undergone an ETO as part of a two-stage revision without spacer placement were matched 1:2 with a cohort of sixty-four patients of the same sex and age who had stem removal without any osteotomy. Clinical outcomes including interim revision, reinfection and aseptic failure rates were evaluated. Modified Harris hip scores (mHHS) were calculated. Minimum follow-up was two years. Results: Patients undergoing ETO had a significantly lower rate of interim re-debridement compared to non-ETO patients (0% vs. 14.1%, p = 0.026). Reinfection following reimplantation was similar in both groups (12.5% in ETO patients vs. 9.4% in non-ETO patients, p = 0.365). Revision for aseptic reason was necessary in 12.5% in the ETO group and 14.1% in the non-ETO group (p = 0.833). Periprosthetic femoral fractures were seen in three patients (3.1%), of which all occurred in non-ETO patients. Dislocation was the most common complication, which was equally distributed in both groups (12.5%). The mean mHHS was 37.7 in the ETO group and 37.3 in the non-ETO group, and these scores improved significantly in both groups following reimplantation (p < 0.01). Conclusion: ETO without the use of spacer is a safe and effective method to manage patients with well-fixed femoral stems and for thorough cement removal in two-stage revision THA for PJI. While it might reduce the rate of repeated debridement in the interim period, the use of ETO appears to lead to similar reinfection rates following reimplantation

Influence of carbon nanoparticle modification on the mechanical and electrical properties of epoxy in small volumes

The influence of nanoparticle morphology and filler content on the mechanical and electrical properties of carbon nanoparticle modified epoxy is investigated regarding small volumes. Three types of particles, representing spherical, tubular and layered morphologies are used. A clear size effect of increasing true failure strength with decreasing volume is found for neat and carbon black modified epoxy. Carbon nanotube (CNT) modified epoxy exhibits high potential for strength increase, but dispersion and purity are critical. In few layer graphene modified epoxy, particles are larger than statistically distributed defects and initiate cracks, counteracting any size effect. Different toughness increasing mechanisms on the nano- and micro-scale depending on particle morphology are discussed based on scanning electron microscopy images. Electrical percolation thresholds in the small volume fibres are significantly higher compared to bulk volume, with CNT being found to be the most suitable morphology to form electrical conductive paths. Good correlation between electrical resistance change and stress strain behaviour under tensile loads is observed. The results show the possibility to detect internal damage in small volumes by measuring electrical resistance and therefore indicate to the high potential for using CNT modified polymers in fibre reinforced plastics as a multifunctional, self-monitoring material with improved mechanical properties