Biomedical subjects

F Graef

Publications and source records attributed to F Graef.

4 recordsLinked to original sources

PubMed2007

Comparison between computer-aided testing and traditional multiple choice: an equivalence study.

AIMS: Computer-aided learning (CAL) is a viable alternative to traditional teaching methods. While CAL is used for teaching only, computer-aided testing (CAT) can be applied as a computer-based examination method. The aim of the present study was to compare the performance of undergraduate students in computer-interactive tests and traditional multiple choice tests and to evaluate the influence of question length and language skills on test results. MATERIALS AND METHODS: Fifty-two native German-speaking students and five non-native speaking students were randomly assigned to two groups. They were required to answer 20 conventional multiple choice questions and 20 questions using the interactive MobiTed system. An analysis of variance and t-tests (alpha = 0.05) were used to compare scores. RESULTS: Non-native speakers scored significantly lower on the interactive test compared with the native speaking students (P = 0.048 for long questions and P = 0.003 for short questions). There were no significant group differences on the conventional multiple choice test (P = 0.052 for long questions and P = 0.089 for short questions). Based on the results of the native speaking students neither test method nor question length had an influence on overall performance. CONCLUSION: Interactive multiple choice tests may provide an alternative to written tests, especially when considering time expenditure. Language skills and question length should be taken into account when setting time limits for examination.

Computer-Assisted Instruction↗

PubMed2006

Stress and inflammation as a detrimental combination for peri-implant bone loss.

The causes of peri-implant bone loss continue to be controversial. To determine the impact of biomechanical stress and inflammation, we investigated a total of 80 interforaminal implants in situ for more than 10 years. Two stress groups, with 14 patients each, were established: a low-stress situation with single-standing implants, and an increased-stress situation with splinted implants. To categorize inflammation, we introduced a Composite Inflammation Score using 4 inflammatory parameters. Peri-implant bone loss was calculated from digital panoramic radiographs. To differentiate between the effects of stress and inflammation, we compared bone loss in both stress groups at equivalent levels of inflammation. With greater Composite Inflammation Score values, a clear discrepancy between single-standing and splinted implants was evident (p = 0.117/0.000, regression analysis; p = 0.135/0.000, analysis of variance; p = 0.002, t tests). While stress and inflammation alone may not necessarily be detrimental factors, the presence of stress heightens peri-implant bone loss significantly as inflammation increases.

Aged↗

PubMed2005

Determining ecoregions for environmental and GMO monitoring networks.

A representative environmental monitoring network at the regional scale cannot use raster-based or random sampling designs, but requires a stratified sampling procedure integrating different information layers, and it has to occur in ecologically differing homogeneous regions (ecoregions). These we have determined using a set of spatial strata with ecological variables which we analysed with classification and regression trees (CART). We present a framework for environmental monitoring, that covers different scales, and we transfer the framework to a potential GMO (genetically modified organisms) monitoring network. We use ecoregion and other environmental strata together with existing environmental monitoring networks to determine GMO monitoring sites more precisely.

Agriculture↗

PubMed2005

Methodological scheme for designing the monitoring of genetically modified crops at the regional scale.

According to EC regulations the deliberate release of genetically modified (GM) crops into the agro-environment needs to be accompanied by environmental monitoring to detect potential adverse effects, e.g. unacceptable levels of gene flow from GM to non-GM crops, or adverse effects on single species or species groups thus reducing biodiversity. There is, however, considerable scientific and public debate on how GM crops should be monitored with sufficient accuracy, discussing questions of potential adverse effects, agro-environmental variables or indicators to be monitored and respective detection methods; Another basic component, the appropriate number and location of monitoring sites, is hardly considered. Currently, no consistent GM crop monitoring approach combines these components systematically. This study focuses on and integrates spatial agro-environmental aspects at a landscape level in order to design monitoring networks. Based on examples of environmental variables associated with the cropping of Bt-Maize (Zea maize L.), herbicide-tolerant (HT) winter oilseed rape (Brassica napus L.), HT sugar beet (Beta vulgaris L.), and starch-modified potato (Solanum tuberosum L.), we develop a transferable framework and assessment scheme that comprises anticipated adverse environmental effects, variables to be measured and monitoring methods. These we integrate with a rule-based GIS (geographic information system) analysis, applying widely available spatial area and point information from existing environmental networks. This is used to develop scenarios with optimised regional GM crop monitoring networks.

Beta vulgaris↗