Hybridization of 20 mer probe oligonucleotides to complementary, surface-immobilized target oligonucleotides was visualized on a single-molecule basis by fluorescence microscopy. Coincident determination of the positions of both the target and the probe oligonucleotides using dual-wavelength fluorescence labeling allowed for highly reliable discrimination of specifically bound probe molecules from those being physisorbed. The figures of merit of the assay are characterized by the low probability for false positive (10(-4)) events and the high speed for detection of up to hundreds of different DNA fragments per second. The probability for false negative events is limited by the biochemical binding probability of short oligonucleotides. The potentials and limitations of this methodology for single-cell single-DNA analysis are discussed.

Only a few studies exist that try to investigate whether there is a significant correlation between external software quality and the data provided by static code analysis tools. A clarification on this issue could pave the way for more precise prediction models on the probability of defects based on the violation of programming rules. We therefore initiated a study where the defect data of selected versions of the open source development environment "Eclipse SDK" is correlated with the data provided by the static code analysis tools PMD and FindBugs applied the source code of Eclipse. The results from this study are promising as especially some PMD rulesets show a good correlation with the defect data and could therefore serve as basis for measurement, control and prediction of software quality.

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There is empirical evidence that internal software quality, e.g., the quality of source code, has great impact on the overall quality of software. Besides well-known manual inspection and review techniques for source code, more recent approaches utilize tool-based static code analysis for the evaluation of internal software quality. Despite the high potential of code analyzers the application of tools alone cannot replace well-founded expert opinion. Knowledge, experience and fair judgment are indispensable for a valid, reliable quality assessment, which is accepted by software developers and managers. The EMISQ method (Evaluation Method for Internal Software Quality), guides the assessment process for all stakeholders of an evaluation project. The method is supported by the Software Product Quality Reporter (SPQR), a tool which assists evaluators with their analysis and rating tasks and provides support for generating code quality reports. The application of SPQR has already proved its usefulness in various code assessment projects around the world. This paper introduces the EMISQ method and describes the tool support needed for an efficient and effective evaluation of internal software quality.

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