Comparing reuse practices in two large software-producing companies

Context Reuse can improve productivity and maintainability in software development. Research has proposed a wide range of methods and techniques. Are these successfully adopted in practice? Objective We propose a preliminary answer by integrating two in-depth empirical studies on software reuse at two large software-producing companies. Method We compare and interpret the study results with a focus on reuse practices, effects, and context. Results Both companies perform pragmatic reuse of code produced within the company, not leveraging other available artefacts. Reusable entities are retrieved from a central repository, if present. Otherwise, direct communication with trusted colleagues is crucial for access. Reuse processes remain implicit and reflect the development style. In a homogeneous infrastructure-supported context, participants strongly agreed on higher development pace and less maintenance effort as reuse benefits. In a heterogeneous context with fragmented infrastructure, these benefits did not materialize. Neither case reports statistically significant evidence of negative side effects of reuse nor inhibitors. In both cases, a lack of reuse led to duplicate implementations. Conclusion Technological advances have improved the way reuse concepts can be applied in practice. Homogeneity in development process and tool support seem necessary preconditions. Developing and adopting adequate reuse strategies in heterogeneous contexts remains challenging

Nachweis von Rickettsien in Zecken aus Mühldorf/Inn, Oberbayern

In einer bisher nicht beprobten Region im Landkreis Mühldorf/Inn wurden zur Bestimmung der Prävalenz und Variabilität von Rickettsien Zecken gescreent und – nach Hinweisen aus früheren Untersuchungen – auf das mögliche Vorkommen einer der Rickettsia (R.) massiliae ähnlichen Rickettsien-Art un-tersucht. Es wurden 1084 Zecken der Art Ixodes (I.) ricinus untersucht, davon 55 Männchen, 79 Weibchen, 941 Nymphen und 9 Larven. Die mittels Flagging gesammelten Tiere wurden in Lysing Matrix A Tubes sortiert und bis zur weite-ren Verarbeitung bei -80°C gelagert. Adulte Zecken wurden einzeln, Nym-phen und Larven ab Probe 531 in Pools zu je drei Stück untersucht. Dabei wurden die Zecken zunächst homogenisiert und Nukleinsäuren extrahiert. Die Eluate wurden mittels einer Pan Rickettsia Real-Time-PCR gescreent. 59 Pro-ben wurden auf Rickettsien positiv getestet. Zur Bestimmung der vorliegenden Rickettsien-Spezies erfolgte mit allen positiven Proben eine R. helvetica spezi-fische Real-Time-PCR und zusätzlich ein Multi Locus Sequence Typing der Genorte 16S rDNA, 5S-23S intergenetic spacer region, OmpA und OmpB mit anschließender Gelelektophorese und Sequenzierung. Von den positiven Proben/Probenpools erwiesen sich 36 als R. helvetica und 5 als R. monacen-sis, 18 Proben/Probenpools ließen sich aufgrund der zu niedrigen Nuklein-säure-Konzentration nicht weiter differenzieren. Proben, die einen cycle-threshold < 35 aufwiesen wurden mittels Shell-Vial-Technik und konventionell in Zellkultur angezüchtet. Aus den Shell Vials fand nach 6-8 Tagen eine Pas-sage in kleine Zellkulturflaschen statt. Der Erfolg der Anzucht wurde mittels Real-Time-PCR durch deutliche Abnahme des cycle-threshold-Werts (≥ 2) ge-zeigt, stichprobenartig wurde zusätzlich ein Nachweis per Immunfluoreszenz durchgeführt. Erfolgreich angezogene Rickettsien wurden mit den Zellen ge-erntet und bei -80°C eingelagert. Insgesamt waren 35 Anzuchten erfolgreich (32 R. helvetica/ 3 R. monacensis). Die Anzucht in Shell Vials zeigte einen deutlich höheren Anzuchterfolg. In den untersuchten Genorten des Multi Locus Sequence Typing zeigten sich keine Unterschiede innerhalb der unter-suchten Rickettsien-Spezies. Die 2004 in der 16S-Sequenz R. massiliae-ähnliche Spezies wurde im beprobten Gebiet nicht erneut nachgewiesen

Who gets to see themselves as talented? Biased self-concepts contribute to first-generation students' disadvantage in talent-focused environments

Intellectual talent is commonly regarded as an important factor for success – i.e., “what it takes to succeed” in Western educational contexts. Yet, the differential experiences individuals have may not allow everyone to think of themselves as talented - i.e., as having “what it takes to succeed” - to the same degree. In five studies with 3584 students in Western countries, we show i) that first-generation students see themselves as less intellectually talented than continuing-generation students, ii) that this bias in self-concept contributes to disadvantages in their academic experience and engagement, and iii) how this disadvantage may be reduced. Quasi-experiments 1a and b (N = 694; 316) show that first-generation students view themselves as relatively less talented, but not less diligent, above and beyond prior performance-levels. Field and experimental Studies 2a-b (N = 1881; 362) show that this bias in students' talent self-concept contributes to disadvantage in first-generation students' academic experience and engagement. Experiment 3 (N = 331) suggests that talent self-concept bias is most consequential in talent-focused environments. If, however, environments emphasize effort, disadvantages connected to talent self-concepts are mitigated. The experiences first-generation students have in current Western environments seem to make them see themselves as relatively less talented, contributing to disadvantage. Creating effort-focused environments can reduce this disadvantage and promote equality

Pick-N multiple choice-exams: a comparison of scoring algorithms

To compare different scoring algorithms for Pick-N multiple correct answer multiple-choice (MC) exams regarding test reliability, student performance, total item discrimination and item difficulty. Data from six 3rd year medical students' end of term exams in internal medicine from 2005 to 2008 at Munich University were analysed (1,255 students, 180 Pick-N items in total). Scoring Algorithms: Each question scored a maximum of one point. We compared: (a) Dichotomous scoring (DS): One point if all true and no wrong answers were chosen. (b) Partial credit algorithm 1 (PS(50)): One point for 100% true answers; 0.5 points for 50% or more true answers; zero points for less than 50% true answers. No point deduction for wrong choices. (c) Partial credit algorithm 2 (PS(1/m)): A fraction of one point depending on the total number of true answers was given for each correct answer identified. No point deduction for wrong choices. Application of partial crediting resulted in psychometric results superior to dichotomous scoring (DS). Algorithms examined resulted in similar psychometric data with PS(50) only slightly exceeding PS(1/m) in higher coefficients of reliability. The Pick-N MC format and its scoring using the PS(50) and PS(1/m) algorithms are suited for undergraduate medical examinations. Partial knowledge should be awarded in Pick-N MC exams

Sustainability in software engineering: a systematic literature review

Background: Supporting sustainability in software engineering is becoming an active area of research. We want to contribute the first Systematic Literature Review(SLR) in this field to aid researchers who are motivated to contribute to that topic by providing a body of knowledge as starting point, because we know from own experience, this search can be tedious and time consuming. Aim: We aim to provide an overview of different aspects of sustainability in software engineering research with regard to research activity, investigated topics, identified limitations, proposed approaches, used methods, available studies, and considered domains. Method: The applied method is a SLR in five reliable and commonly-used databases according to the (quasi-standard) protocol by Kitchenham et al. [1]. We assessed the 100 first results of each database ordered by relevance with respect to the search query. Results: Of 500 classified publications, we regard 96 as relevant for our research questions. We sketch a taxonomy of their topics and domains, and provide lists of used methods and proposed approaches. Most of the excluded publications were ruled out because of an unfitting usage of terms within the search query. Conclusions: Currently, there is little research coverage on the different aspects of sustainability in software engineering while other disciplines are already more active. Future work includes extending the study by reviewing a higher number of publications, including dedicated journal and workshop searches, and snowballing.Peer ReviewedPostprint (author's final draft