Strong field limit analysis of gravitational retro-lensing

We present a complete treatment in the strong field limit of gravitational retro-lensing by a static spherically symmetric compact object having a photon sphere. The results are compared with those corresponding to ordinary lensing in similar strong field situations. As examples of application of the formalism, a supermassive black hole at the galactic center and a stellar mass black hole in the galactic halo are studied as retro-lenses, in both cases using the Schwarzschild and Reissner-Nordstrom geometries.Comment: 11 pages, 1 figure; v2: minor changes. Accepted for publication in Physical Review

EHEC-associated hemolytic uremic syndrome

Das hämolytisch-urämische Syndrom (HUS) ist ein lebensbedrohlicher Zustand, charakterisiert durch akutes Nierenversagen, hämolytische Anämie und Thrombozytopenie. In >80% der Fälle liegen gastrointestinale Infektionen mit enterohämorrhagischen Escherichia coli (EHEC) zugrunde. Diese enterisch-infektiöse (enteropathische) Form des HUS tritt meist bei Kindern unter 6 Jahren auf. Da u. U. rasch eine Blutreinigung eingeleitet werden muss, sollten die Betroffenen in spezialisierten Kinderdialysezentren behandelt werden. Aufgrund der überwiegend enterisch-infektiösen Ätiologie können vereinzelt auftretende Fälle wichtige Hinweise auf Erkrankungshäufungen liefern. In Deutschland treten Infektionen mit einer seltenen Sorbitol fermentierenden Variante von EHEC O157 auf, die schon mehrfach in HUS-Krankheitsausbrüchen mit Todesfällen resultierten. Bereits der Verdacht sowie die Erkrankung oder der Tod an enteropathischem HUS sind durch den feststellenden Arzt unverzüglich an das zuständige Gesundheitsamt zu melden. Dadurch können zeitnah Maßnahmen zur Verhinderung der Ausbreitung der Infektion getroffen werden. Die epidemischen Aspekte des EHEC-assoziierten HUS werden dargestellt, und Kinderärzten Hilfestellungen im Hinblick auf eine frühzeitige Diagnose und Meldung gegeben.Hemolytic uremic syndrome (HUS) is a life-threatening condition characterized by acute renal failure, hemolytic anemia and thrombocytopenia. More than 80% of pediatric HUS is caused by infection with enterohemorrhagic Escherichia coli (EHEC). EHEC-associated HUS mainly affects children under six years of age. HUS patients should be treated in specialized clinics, which are able to provide dialysis. Importantly, sporadic cases of HUS can signalize outbreaks of EHEC infections. In Germany, a rare sorbitol-fermenting variant of EHEC O157 caused several large HUS outbreaks with fatal cases. Physicians are required to notify every suspected, confirmed or fatal case of HUS to their local health department, thereby enabling public health authorities to intervene promptly. This article describes the epidemic aspects of EHEC-associated HUS and assists physicians and pediatricians in terms of timely diagnosis and notification

Is public capital productive in Europe?

This paper addresses the issue of whether and by how much public investment or public capital can increase GDP. In comparison with the literature on the subject, we apply many different methodologies to answer these questions. A vector autoregressive (VAR) model (for France, Italy, Germany, the UK and the USA), a panel composed of 6 European countries (Austria, Belgium, France, Germany, Italy and the Netherlands) and a regional panel (French regions) are estimated. Public investment is shown to be a significant determinant of output; this is also true for public capital but to a lesser extent than public investment with a VAR methodology. The size of the estimated coefficient is also more realistic than those obtained in the literature. This empirical result confirms that the focus of some economists on safeguarding the level of public investment is not misplaced. The debate on the introduction of a ‘golden rule of public finance’ in the European Monetary Union is legitimate in this respect.public capital, public investment, VAR, panel data, European countries, E62, H54, C23,