Suchergebnisse

Die Formeln für Mittelwert und Standardabweichung kennt man auswendig, viel mehr aber meist nicht! Zur Unterstützung gibt es nun diese kompakte Formelsammlung, die die wichtigsten Formeln und Testverfahren der Statistik übersichtlich zusammengestellt. So knapp wie möglich, so umfangreich wie nötig: mit Voraussetzungen für die Anwendung eines Tests, Angaben zu Stichprobengrößen und Konfidenzintervallen. Ob deskriptive oder Inferenzstatistik - die ersten Formeln und statistischen Testverfahren (t-Test, F-Test etc.) mögen noch verständlich und gut herzuleiten sein. Aber alle Formeln kann man sich nicht merken - und das muss man auch nicht. Der übersichtliche Aufbau und die Zusammenstellung aller notwendigen Informationen zu einer Formel oder einem Test ermöglichen schnelles und unkompliziertes Nachschlagen. Prof. Dr. Michael Eid, Lehrstuhl Methoden und Evaluation, FU Berlin.

Yersinia enterocolitica is generally considered an important food-borne pathogen worldwide, especially in the European Union. A lytic Yersinia phage X1 (Viruses; dsDNA viruses, no RNA stage; Caudovirales; and Myoviridae) was isolated. Phage X1 showed a broad host range and could effectively lyse 27/51 Y. enterocolitica strains covering various serotypes that cause yersiniosis in humans and animals (such as serotype O3 and serotype O8). The genome of this phage was sequenced and analyzed. No toxin, antibiotic-resistance or lysogeny related modules were found in the genome of phage X1. Studies of phage stability confirmed that X1 had a high tolerance toward a broad range of temperatures (4–60°C) and pH values (4–11) for 1 h. The ability to resist harsh acidic conditions and enzymatic degradation in vitro demonstrated that phage X1 is suitable for oral administration, and in particular, that this phage can pass the stomach barrier and efficiently reach the intestine in vivo without losing infectious ability. The potential of this phage against Y. enterocolitica infection in vitro was studied. In animal experiments, a single oral administration of phage X1 at 6 h post infection was sufficient to eliminate Y. enterocolitica in 33.3% of mice (15/45). In addition, the number of Y. enterocolitica strains in the mice was also dramatically reduced to approximately 10(3) CFU/g after 18 h compared with 10(7) CFU/g in the mice without phage treatment. Treatment with phage X1 showed significant improvement by intestinal histopathologic observations. Moreover, proinflammatory cytokine levels (IL-6, TNF-α, and IL-1β) were significantly reduced (P < 0.05). These results indicate that phage X1 is a promising candidate to control infection by Y. enterocolitica in vivo.