1000 resultados para Fanning, Charlotte Fall, 1809-1896.


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by T.K. Cheyne

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Antihydrogen holds the promise to test, for the first time, the universality of freefall with a system composed entirely of antiparticles. The AEgIS experiment at CERN’s antiproton decelerator aims to measure the gravitational interaction between matter and antimatter by measuring the deflection of a beam of antihydrogen in the Earths gravitational field (g). The principle of the experiment is as follows: cold antihydrogen atoms are synthesized in a Penning-Malberg trap and are Stark accelerated towards a moir´e deflectometer, the classical counterpart of an atom interferometer, and annihilate on a position sensitive detector. Crucial to the success of the experiment is the spatial precision of the position sensitive detector.We propose a novel free-fall detector based on a hybrid of two technologies: emulsion detectors, which have an intrinsic spatial resolution of 50 nm but no temporal information, and a silicon strip / scintillating fiber tracker to provide timing and positional information. In 2012 we tested emulsion films in vacuum with antiprotons from CERN’s antiproton decelerator. The annihilation vertices could be observed directly on the emulsion surface using the microscope facility available at the University of Bern. The annihilation vertices were successfully reconstructed with a resolution of 1–2 μmon the impact parameter. If such a precision can be realized in the final detector, Monte Carlo simulations suggest of order 500 antihydrogen annihilations will be sufficient to determine gwith a 1 % accuracy. This paper presents current research towards the development of this technology for use in the AEgIS apparatus and prospects for the realization of the final detector.

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Ein persistierender Ductus arteriosus (Ductus Botalli) ist seit Jahren als Ursache eines plötzlichen und unerwarteten Neugeborenentods und pulmonaler Hämorrhagien identifiziert. Insbesondere Frühgeborene weisen ein erhöhtes Risiko zur Entwicklung eines hämodynamisch signifikanten persistierenden Ductus arteriosus auf. Vorgestellt wird der plötzliche und unerwartete Todesfall eines 4 Tage alt gewordenen Säuglings, der 2 Wochen vor dem errechneten Termin geboren worden war. Bei der Obduktion zeigte sich ein sehr muskelkräftiger arterieller Gefäßkurzschluss zwischen der A. pulmonalis und dem Aortenbogen mit einem Durchmesser knapp unter dem der A. pulmonalis. Als Folge der pulmonalen Hyperperfusion fanden sich eine massive akute Blutstauung und kongestives Herzversagen infolge des „shunting“ von der systemischen in die pulmonale Zirkulation.

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[Originalfotografie von C. F. Mylius]