Restrukturierung objektorientierter Datenbankschemata mittels formaler Begriffsanalyse

Zusammenfassung.   Eine Restrukturierung eines gegebenen Datenbankschemas kann aus unterschiedlichen Gründen notwendig werden. So kann dadurch z.B. die Verst?ndlichkeit des Schemas verbessert werden. Im Bereich der relationalen Datenbanken steht die Normalisierungstheorie zur Verfügung, um z.B. Redundanz zu vermeiden. Der Normalisierung liegt dabei ein Begriff der ?quivalenz von Datenbankschemata zugrunde. Im Bereich der objektorientierten Datenbanken gibt es bislang kaum vergleichbare Ans?tze. In diesem Beitrag pr?sentieren wir daher einen Ansatz, mit dem Klassenhierarchien in objektorientierten Datenbankschemata in eine „normalisierte” Form transformiert werden k?nnen. Dazu mu? zun?chst eine extensionale Analyse durchgeführt werden, die die notwendigen Informationen über extensionale Beziehungen zwischen den gegebenen Klassen liefert. Anschlie?end wenden wir Konzepte der formalen Begriffsanalyse an, um eine „normalisierte” Klassenhierarchie abzuleiten. Eingegangen am 16. Januar 1999 / Angenommen am 3. Oktober 1999     

Can high stakes national testing improve instruction: reexamining conventional wisdom

In this paper, the authors draw on recent international experience to assess the success of five propositions for how high stakes national testing can improve classroom instruction and, ultimately, raise student achievement. Findings indicate that testing can be an effective mechanism for improving instructional practice, but its success is not ensured. It has failed as often as it has succeeded, usually because those implementing the strategy failed to understand the intermediate conditions that had to be met for changes in test content, format, or use to have the desired impact on teachers' classroom practice.     

Assay validity of point-of-care platelet function tests in thrombocytopenic blood samples

IntroductionPoint-of-care (POC) platelet function tests are faster and easier to perform than in-depth assessment by flow cytometry. At low platelet counts, however, POC tests are prone to assess platelet function incorrectly. Lower limits of platelet count required to obtain valid test results were defined and a testing method to facilitate comparability between different tests was established.Materials and methodsWe assessed platelet function in whole blood samples of healthy volunteers at decreasing platelet counts (> 100, 80-100, 50-80, 30-50 and < 30 x10⁹/L) using two POC tests: impedance aggregometry and in-vitro bleeding time. Flow cytometry served as the gold standard. The number of platelets needed to reach 50% of the maximum function (ED₅₀) and the lower reference limit (ED_ref) were calculated to define limits of test validity.ResultsThe minimal platelet count required for reliable test results was 100 x10⁹/L for impedance aggregometry and in-vitro bleeding time but only 30 x10⁹/L for flow cytometry. Comparison of ED₅₀ and ED_ref showed significantly lower values for flow cytometry than either POC test (P value < 0.05) but no difference between POC tests nor between the used platelet agonists within a test method.ConclusionCalculating the ED₅₀ and ED_ref provides an effective way to compare values from different platelet function assays. Flow cytometry enables correct platelet function testing as long as platelet count is > 30 x10⁹/L whereas impedance aggregometry and in-vitro bleeding time are inconsistent unless platelet count is > 100 x10⁹/L.     

Reading Orthographically Strange Nonwords: Modelling Backup Strategies in Reading

The latest version of the connectionist dual process model of reading (CDP++.parser) was tested on a set of nonwords, many of which were orthographically strange (e.g., PSIZ). A grapheme-by-grapheme read-out strategy was used because the normal strategy produced many poor responses. The new strategy allowed the model to produce results similar to individual participants. Given that the strategy uses only simple information acquired in the normal course of learning, it shows that it is a plausible method for reading when the normal method fails and offers insight into how groups with low orthographic exposure might read.     

INTEGRATING RESOURCE DEVELOPMENT AND INSTITUTIONAL PLANNING

Fundraising has long been a central activity in four‐year institutions, whereas community colleges have only recently begun to see the necessity for such efforts. Resource development and private fundraising as a community college function have only been marginally understood and often are only instigated in times of financial crises. In today's educational arena, development needs to become a long‐term core function in order to maximize the funding base of community colleges. This article gives a brief look at the historical background of fundraising in community colleges, contrasts such efforts with the four‐year institutions, and discusses the matter of integrating resource development with institutional planning processes. Several examples of successful community college development efforts are given, along with a discussion of several planning models that might be used as guides for integrating resource development efforts with institutional planning.     

ACADEMIC PERFORMANCE OF COMMUNITY COLLEGE TRANSFER STUDENTS AND "NATIVE" STUDENTS AT A LARGE STATE UNIVERSITY

Students were randomly chosen from the class of 1998 and 1999 at a large public university. Fifty in each class were community college transfer students who transferred to the university in the fall of 1996 and fall of 1997; 50 in each class were native students who had entered the university in the fall of 1994 and the fall of 1995. All students were from the College of Arts and Sciences. These groups of students were compared by GPAs at the end of the lower division work (sophomore year for natives and at the end of the second year of community college work for transfers). Students also were compared at the end of their first semester in their academic major to determine if transfer shock was evident for transfer students and if a GPA decline was evident for natives. Lastly, the students GPAs were compared at the end of the spring semesters of 1998 and 1999 to determine if there was recovery from transfer shock for the transfers and from the possible decline in GPA for native students. Retention and graduation rates for both groups were compared.