4,481 research outputs found

    More than one way to see it: Individual heuristics in avian visual computation

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    Comparative pattern learning experiments investigate how different species find regularities in sensory input, providing insights into cognitive processing in humans and other animals. Past research has focused either on one species’ ability to process pattern classes or different species’ performance in recognizing the same pattern, with little attention to individual and species-specific heuristics and decision strategies. We trained and tested two bird species, pigeons (Columba livia) and kea (Nestor notabilis, a parrot species), on visual patterns using touch-screen technology. Patterns were composed of several abstract elements and had varying degrees of structural complexity. We developed a model selection paradigm, based on regular expressions, that allowed us to reconstruct the specific decision strategies and cognitive heuristics adopted by a given individual in our task. Individual birds showed considerable differences in the number, type and heterogeneity of heuristic strategies adopted. Birds’ choices also exhibited consistent species-level differences. Kea adopted effective heuristic strategies, based on matching learned bigrams to stimulus edges. Individual pigeons, in contrast, adopted an idiosyncratic mix of strategies that included local transition probabilities and global string similarity. Although performance was above chance and quite high for kea, no individual of either species provided clear evidence of learning exactly the rule used to generate the training stimuli. Our results show that similar behavioral outcomes can be achieved using dramatically different strategies and highlight the dangers of combining multiple individuals in a group analysis. These findings, and our general approach, have implications for the design of future pattern learning experiments, and the interpretation of comparative cognition research more generally

    Improved Skin Friction Interferometer

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    An improved system for measuring aerodynamic skin friction which uses a dual-laser-beam oil-film interferometer was developed. Improvements in the optical hardware provided equal signal characteristics for each beam and reduced the cost and complexity of the system by replacing polarization rotation by a mirrored prism for separation of the two signals. An automated, objective, data-reduction procedure was implemented to eliminate tedious manual manipulation of the interferometry data records. The present system was intended for use in two-dimensional, incompressible flows over a smooth, level surface without pressure gradient, but the improvements discussed are not limited to this application

    Expendable bubble tiltmeter for geophysical monitoring

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    An unusually rugged highly sensitive and inexpensive bubble tiltmeter has been designed, tested, and built in quantity. These tiltmeters are presently used on two volcanoes and an Alaskan glacier, where they continuously monitor surface tilts of geological interest. This paper discusses the mechanical, thermal, and electric details of the meter, and illustrates its performance characteristics in both large ( > 10^(-4) radian) and small ( < 10^(-6) radian) tilt environments. The meter's ultimate sensitivity is better than 2 X 10^(-8) radians rms for short periods (hours), and its useful dynamic range is greater than 10^4. Included is a short description of field use of the instrument for volcano monitoring

    l. suis medication of piglets with Baycoxo 5% against coccidiose and for stabilisation of the microflora against intestinal infections and reducing the application of antibiotica and vaccines against diarrhoea with E.coli and Clostridia

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    After the oral treatment of all p1glets 3 - 5 days after birth with Baycox 5% we found a better intestine health in the suckling and in the flatdeck period. ln this study there was a reduced diarrhoea dunng suckling and in the flatdeck.With the Baycox• therapeutic the vaccination program against E. coli and Clostridium perfringens Typ C and the application of antibiotica to the weaners could be decreased for nearly 40 % during the breeding period. AII pigs got better health status with higher weight gain and uniformity

    Ultraviolet downconverting phosphor for use with silicon CCD imagers

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    The properties and application of a UV downconverting phosphor (coronene) to silicon charge coupled devices are discussed. Measurements of the absorption spectrum have been extended to below 1000 A, and preliminary results indicate the existence of useful response to at least 584 A. The average conversion efficiency of coronene was measured to be ~20% at 2537 A. Imagery at 3650 A using a backside illuminated 800 X 800 CCD coated with coronene is presented

    The pan-European order at the crossroads: three principles for a new beginning

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    The year 2014 confronted European policy-makers with a qualitatively altered situation. For the first time in many years an interstate conflict in Europe - manifested as an inner-state conflict - is being resolved by military means. Persistent uncertainty and a growing potential for conflict are the new realities the European Union (EU) must face - in its eastern neighborhood as well as in the Mediterranean region. This neighborhood also holds major strategic significance for the supply of energy to Europe. In order to limit the risks, it is necessary to define and construct a new pan-European order - based on existing conditions - that can rein in the potential for conflict, ensure greater predictability and build new trust. Germany should use its OSCE chairmanship in 2016 to initiate negotiations to this effect along the lines of new principles, with a view to establishing a pan-European order with a strong energy component as its core. (author's abstract

    Thermal detector model for cryogenic composite detectors for the dark matter experiments CRESST and EURECA

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    The CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) and the EURECA (European Underground Rare Event Calorimeter Array) experiments are direct dark matter search experiments where cryogenic detectors are used to detect spin-independent, coherent WIMP (Weakly Interacting Massive Particle)-nucleon scattering events by means of the recoil energy. The cryogenic detectors use a massive single crystal as absorber which is equipped with a TES (transition edge sensor) for signal read-out. They are operated at mK-temperatures. In order to enable a mass production of these detectors, as needed for the EURECA experiment, a so-called composite detector design (CDD) that allows decoupling of the TES fabrication from the optimization procedure of the absorber single-crystal was developed and studied. To further investigate, understand and optimize the performance of composite detectors a detailed thermal detector model which takes into account the CDD has been developed.Comment: To appear in Journal of Physics: Conference Series; Proceedings of Neutrino 2008, Christchurch, New Zealan
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