Predicting students drop out : a case study

The monitoring and support of university freshmen is considered very important at many educational institutions. In this paper we describe the results of the educational data mining case study aimed at predicting the Electrical Engineering (EE) students drop out after the first semester of their studies or even before they enter the study program as well as identifying success-factors specific to the EE program. Our experimental results show that rather simple and intuitive classifiers (decision trees) give a useful result with accuracies between 75 and 80%. Besides, we demonstrate the usefulness of cost-sensitive learning and thorough analysis of misclassifications, and show a few ways of further prediction improvement without having to collect additional data about the students

High risk of cardiovascular mortality in individuals with impaired fasting glucose is explained by conversion to diabetes - The Hoorn Study

OBJECTIVE: To optimize identification of future diabetic patients, the American Diabetes Association (ADA) introduced criteria for impaired fasting glucose (IFG) in 1997 (IFG 6.1 mmol/l [IFG6.1]) and lowered the threshold from 6.1 to 5.6 mmol/l (IFG5.6) in 2003. Our aim was to assess the consequences of lowering the IFG cutoff on the risk of cardiovascular disease (CVD) mortality and to evaluate whether this risk is explained by a conversion to type 2 diabetes within 6.4 years. RESEARCH DESIGN AND METHODS: In a population-based cohort, the Hoorn Study, plasma glucose was determined in 1989 and 1996 (n = 1,428). Subjects were classified in 1989 according to 1997 and 2003 ADA criteria. Subjects with IFG in 1989 were further classified according to diabetes status in 1996. Hazard ratios for CVD mortality (n = 81) in the period 1996-2005 were adjusted for age and sex. RESULTS: Subjects with IFG6.1, but not IFG5.6, had a significantly higher CVD mortality risk than normal fasting glucose (NFG) subjects. Subjects who converted from IFG to diabetes (IFG6.1: 42%; IFG5.6: 21%) had a more than twofold risk of CVD mortality (IFG6.1: 2.47 [1.17-5.19]; IFG5.6: 2.14 [1.12-4.10]) than subjects with NFG. IFG subjects who did not develop diabetes did not have significantly higher CVD mortality risks (IFG6.1: 1.50 [0.72-3.15]; IFG5.6: 1.15 [0.69-1.93]). CONCLUSIONS: The lower cutoff for IFG (ADA 2003 criteria) results in a category of IFG that no longer represents a high-risk state of CVD. Furthermore, only subjects who convert from IFG to diabetes have a high risk of CVD mortality

Pectobacterium carotovorum subsp carotovorum can cause potato blackleg in temperate climates

It is well established that the pectinolytic bacteria Pectobacterium atrosepticum (Pca) and Dickeya spp. are causal organisms of blackleg in potato. In temperate climates, the role of Pectobacterium carotovorum subsp. carotovorum (Pcc) in potato blackleg, however, is unclear. In different western and central European countries plants are frequently found with blackleg from which only Pcc can be isolated, but not Pca or Dickeya spp. Nevertheless, tubers vacuum-infiltrated with Pcc strains have so far never yielded blackleg-diseased plants in field experiments in temperate climates. In this study, it is shown that potato tubers, vacuum-infiltrated with a subgroup of Pcc strains isolated in Europe, and planted in two different soil types, can result in up to 50% blackleg diseased plants

Operations Research for Green Logistics – An Overview of Aspects, Issues, Contributions and Challenges

The worldwide economic growth of the last century has given rise to a vast consumption of goods while globalization has led to large streams of goods all over the world. The production, transportation, storage and consumption of all these goods, however, have created large environmental problems. Today, global warming, created by large scale emissions of greenhouse gasses, is a top environmental concern. Governments, action groups and companies are asking for measures to counter this threat. Operations research has a long tradition in improving operations and especially in reducing costs. In this paper, we present a review that highlights the contribution of operations research to green logistics, which involves the integration of environmental aspects in logistics. We give a sketch of the present and possible developments, focussing on design, planning and control in a supply chain for transportation, inventory of products and facility decisions. While doing this, we also indicate several areas where environmental aspects could be included in OR models for logistics

L'image en expansion : plaisir de la retransmission sportive et enjeux esthétiques

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