University of Hohenheim

About: University of Hohenheim is a education organization based out in Stuttgart, Germany. It is known for research contribution in the topics: Population & Soil water. The organization has 8585 authors who have published 16406 publications receiving 567377 citations.

Die Validität von Schulnoten zur Vorhersage des Studienerfolgs - eine Metaanalyse.

Abstract: Zusammenfassung. Schulabschlussnoten sind trotz erweiterter Moglichkeiten der Universitaten und Kritik an der Hinlanglichkeit zur Vorhersage des Studienerfolgs nach wie vor das haufigste Einzelkriterium, das zur Auswahl von Studierenden in Deutschland herange- zogen wird. Die vorliegende Metaanalyse integriert die seit 1980 publizierten europaischen Studien zum Zusammenhang von einzelnen und durchschnittlichen Schulnoten einerseits und dem Studienerfolg andererseits (insgesamt 83 Koeffizienten). Es ergeben sich mittlere korrigierte Validitatskoeffizienten in Hohe von .26 bis .53 fur das Studienerfolgskriterium Studiennoten. Die hochste Validitat weisen deutsche Schuldurchschnittsnoten auf (ρ = .53, korrigiert fur die Reliabilitat der Studiennoten und die Varianzeinschrankung durch Selektion). Moderatoranalysen zeigen signifikante Einflusse des Landes, des Studienfachs, der Zeitspanne zwischen Schul- und Studien- leistung und des Studienabschnitts der Studienleistung. Die fur Schulnoten berechneten Validitatskoeffizienten sind generalisierbar positiv und von Null verschieden. Abstract. Although school grades are often criticized and universities in Germany are now allowed to use other criteria of selection, high school grades are still used most often to admit students to university. The present meta-analysis includes all European studies that have been published since 1980 and investigated the relationship between school grades and university grades (altogether 83 coefficients). Grade point average and individual subject grades were accepted as predictors. The mean corrected validity for school grades ranges from .26 to .53, using undergraduate or graduate grades to measure academic success. Highest validity was found for German grade point average (ρ = .53, corrected). Analyses of moderator-effects show significant influences of country of origin, study major, time between school and university grades, and study period. The computed validity coefficients for school grades are positive and different from zero.

The formation of biogenic amines by fermentation organisms

Abstract: A total of 523 strains representing 35 species related to food fermentation organisms of practical importance were investigated for their potential for formation of biogenic amines (BA). The investigation was performed with resting cells in phosphate buffer (pH 5.5) and the formation of the following BAs was followed: putrescine, cadaverine, histamine, tyramine and 2-phenylethylamine. No potential was observed in species of lactococcus, Leuconostoc, Pediococcus, Streptococcus and several Lactobacillus spp., such as L. Pentosus and L. sake. A remarkable potential to form BA was observed in strains of carnobacteria, Lactobacillus buchneri, L. curvatus, L. reuteri, Staphylococcus carnosus and, to a lesser extent, in L. alimentarius, L. brevis, L. bavaricus, L. delbrueckii ssp. lactis, Micrococcus spp. and S. piscifermentans. In well known species with a practical function in the fermentation of dairy products, wine or cabbage a potential was observed for few strains only. In view of their role as starters in food fermentation, or their potential use in protective cultures and as probiotics, BA formation by the organisms has to be taken into consideration by selecting appropriate strains.

Importance of Cell Wall Degrading Enzymes Produced by Fusarium graminearum during Infection of Wheat Heads

Abstract: Cytological studies were carried out to elucidate the importance of cell wall degrading enzymes (CWDE) during infection of wheat spikes by Fusarium graminearum. Scanning electron micrographs revealed that at 6–24 hours after inoculation (hai) of single spikelets with macroconidia of F. graminearum, the fungus germinated by forming several germ tubes and developed a dense hyphal network in the cavity of the spikelet. At 24–36hai, the fungus formed infection hyphae which invaded the ovary and inner surface of the lemma and palea. Transmission electron microscopical studies revealed that the fungus extended inter- and intracellularly in the ovary, lemma and rachis and caused considerable damage and alterations to the host cell walls. In different tissues of healthy and F. graminearum-infected wheat spikes the cell wall components cellulose, xylan and pectin were localized by means of enzyme-gold and immuno-gold labelling techniques. Localization of cellulose, xylan and pectin showed that host cell walls which were in direct contact with the pathogen surface had reduced gold labelling compared to considerable higher labelling densities of walls distant from the pathogen–host interface or in non-colonized tissues. The reduced gold labelling densities in the infected host cell walls indicate that these polysaccharide degrading enzymes might be important pathogenicity factors of F. graminearum during infection of wheat spikes. The results revealed that, infection and colonization of wheat spikes by F. graminearum and reactions of infected host tissue were similar to those reported for F. culmorum.

Identification and population dynamics of yeasts in sourdough fermentation processes by PCR-denaturing gradient gel electrophoresis.

Abstract: Four sourdoughs (A to D) were produced under practical conditions, using a starter obtained from a mixture of three commercially available sourdough starters and baker's yeast. The doughs were continuously propagated until the composition of the microbiota remained stable. A fungi-specific PCR-denaturing gradient gel electrophoresis (DGGE) system was established to monitor the development of the yeast biota. The analysis of the starter mixture revealed the presence of Candida humilis, Debaryomyces hansenii, Saccharomyces cerevisiae, and Saccharomyces uvarum. In sourdough A (traditional process with rye flour), C. humilis dominated under the prevailing fermentation conditions. In rye flour sourdoughs B and C, fermented at 30 and 40°C, respectively, S. cerevisiae became predominant in sourdough B, whereas in sourdough C the yeast counts decreased within a few propagation steps below the detection limit. In sourdough D, which corresponded to sourdough C in temperature but was produced with rye bran, Candida krusei became dominant. Isolates identified as C. humilis and S. cerevisiae were shown by randomly amplified polymorphic DNA-PCR analysis to originate from the commercial starters and the baker's yeast, respectively. The yeast species isolated from the sourdoughs were also detected by PCR-DGGE. However, in the gel, additional bands were visible. Because sequencing of these PCR fragments from the gel failed, cloning experiments with 28S rRNA amplicons obtained from rye flour were performed, which revealed Cladosporium sp., Saccharomyces servazii, S. uvarum, an unculturable ascomycete, Dekkera bruxellensis, Epicoccum nigrum, and S. cerevisiae. The last four species were also detected in sourdoughs A, B, and C.