Equation of Motion of Small Bodies in Relativity

There is proven a theorem, to the effect that a material body in general relativity, in a certain limit of sufficiently small size and mass, moves along a geodesic.Comment: 7 page

Schwarzschild and Synge once again

We complete the historical overview about the geometry of a Schwarzschild black hole at its horizon by emphasizing the contribution made by J. L. Synge in 1950 to its clarification.Comment: 2 pages, LaTeX, submitted for publication; 2 references, one Note, and an Acknowledgement are adde

The “Missing Glaciations” of the Middle Pleistocene

Global glaciations have varied in size and magnitude since the Early-Middle Pleistocene transition (~773 ka), despite the apparent regular and high-amplitude 100 kyr pacing of glacial-interglacial cycles recorded in marine isotopic records. The evidence on land indicates that patterns of glaciation varied dramatically between different glacial-interglacial cycles. For example, MIS (Marine Isotope Stages) 8, 10 and 14 are all noticeably absent from many terrestrial glacial records in North America and Europe. However, globally, the patterns are more complicated with major glaciations recorded in MIS 8 in Asia and in parts of the Southern Hemisphere, such as Patagonia for example. This spatial variability in glaciation between glacial-interglacial cycles is likely to be driven by ice volume changes in the West Antarctic Ice Sheet and associated interhemispheric connections through ocean-atmosphere circulatory changes. The weak global glacial imprint in some glacial-interglacial cycles is related to the pattern of global ice build-up. This is caused by feedback mechanisms within glacier systems themselves which partly result from long-term orbital changes driven by eccentricity.n/

The Theory of Caustics and Wavefront Singularities with Physical Applications

This is intended as an introduction to and review of the work of V, Arnold and his collaborators on the theory of Lagrangian and Legendrian submanifolds and their associated maps. The theory is illustrated by applications to Hamilton-Jacobi theory and the eikonal equation, with an emphasis on null surfaces and wavefronts and their associated caustics and singularities.Comment: Figs. not include

Elsterzeitliche (Anglian) Eisdynamik in East Anglia

Gefügeuntersuchungen in Aufschlüssen in East Anglia haben gezeigt, daß während der Elster-Vereisung (Anglian) ein Eisvorstoß aus dem Nordseebecken von einem Vorstoß britischen Eises erst aus westlicher, später aus nördlicher Richtung gefolgt wurde. Durch das ungleichzeitige Vorstoßen und Abschmelzen der beiden Eisschilde und durch die isostatische Absenkung im Nordsee-Bereich hat sich zeitweise eine nach NE gerichtete Eisbewegung ergeben.researc

Active Mass Under Pressure

After a historical introduction to Poisson's equation for Newtonian gravity, its analog for static gravitational fields in Einstein's theory is reviewed. It appears that the pressure contribution to the active mass density in Einstein's theory might also be noticeable at the Newtonian level. A form of its surprising appearance, first noticed by Richard Chase Tolman, was discussed half a century ago in the Hamburg Relativity Seminar and is resolved here.Comment: 28 pages, 4 figure

Blended Assessment: Mündliche und elektronische Prüfungen im klinischen Kontext

Die Curriculumsreform in der Tiermedizin und die Einführung des „praktischen Jahres“ an der Tierärztlichen Hochschule Hannover machten es notwendig, die klinischen Prüfungen in zwei Teilen durchzuführen. Eine Kombination aus schriftlicher und mündlicher Prüfung wurde gewählt. In der vorliegenden Studie werden Erfahrungen mit verschiedenen Prüfungsformen hinsichtlich ihrer Effizienz und Qualität verglichen: mündliche Prüfungen, papiergestützte schriftliche Prüfungen und elektronische Prüfungen. Zusätzlich wurden Studierende und Dozierende zu den Prüfungsformen befragt. Durch Einführung der elektronischen Teilprüfungen wurde eine Effizienz- und Qualitätssteigerung erreicht. Die Akzeptanz bei den Studierenden ist gut, bei den Prüfenden herrschen noch gewisse Ressentiments. Mit der Einführung elektronischer Prüfungen wurde der richtige Weg eingeschlagen; um die Qualität weiter zu steigern, sind aber Fortbildung der PrüferInnen und die Weiterentwicklung der Itemformate notwendig. 31.01.2010 | Jan P. Ehlers, Torsten Carl, Karl-Heinz Windt, Daniel Möbs, Jürgen Rehage & Andrea Tipold (Hannover / Bergisch Gladbach

Foodborne hepatitis A outbreak associated with bakery products in northern Germany, 2012

In October 2012, a hepatitis A (HA) outbreak with 83 laboratory-confirmed cases occurred in Lower Saxony. We defined primary outbreak cases as people with laboratory-confirmed HA and symptom onset between 8 October and 12 November 2012, residing in or visiting the affected districts. Secondary outbreak cases were persons with symptom onset after 12 November 2012 and close contact with primary cases. We identified 77 primary and six secondary cases. We enrolled 50 primary cases and 52 controls matched for age and sex, and found that 82% of cases and 60% of controls had consumed products from a particular bakery (OR=3.09; 95% CI: 1.15–8.68). Cases were more likely to have eaten sweet pastries (OR=5.74; 95% CI: 1.46–22.42). Viral isolates from five selected cases and three positively tested surfaces in the bakery had identical nucleotide sequences. One additional identical isolate derived from a salesperson of the bakery suffering from a chronic disease that required immunosuppressive treatment. Epidemiological and laboratory findings suggested that the salesperson contaminated products while packing and selling. Future risk assessment should determine whether food handlers with chronic diseases under immunosuppressive treatment could be more at risk of contaminating food and might benefit from HAV immunisation

Newtonian Cosmology in Lagrangian Formulation: Foundations and Perturbation Theory

The ``Newtonian'' theory of spatially unbounded, self--gravitating, pressureless continua in Lagrangian form is reconsidered. Following a review of the pertinent kinematics, we present alternative formulations of the Lagrangian evolution equations and establish conditions for the equivalence of the Lagrangian and Eulerian representations. We then distinguish open models based on Euclidean space $\R^3$ from closed models based (without loss of generality) on a flat torus \T^3. Using a simple averaging method we show that the spatially averaged variables of an inhomogeneous toroidal model form a spatially homogeneous ``background'' model and that the averages of open models, if they exist at all, in general do not obey the dynamical laws of homogeneous models. We then specialize to those inhomogeneous toroidal models whose (unique) backgrounds have a Hubble flow, and derive Lagrangian evolution equations which govern the (conformally rescaled) displacement of the inhomogeneous flow with respect to its homogeneous background. Finally, we set up an iteration scheme and prove that the resulting equations have unique solutions at any order for given initial data, while for open models there exist infinitely many different solutions for given data.Comment: submitted to G.R.G., TeX 30 pages; AEI preprint 01