Enlarging a training set for genomic selction by imputation of un-genotyped animals in populations of varying genetic architecture

Background: The most common application of imputation is to infer genotypes of a high-density panel of markers on animals that are genotyped for a low-density panel. However, the increase in accuracy of genomic predictions resulting from an increase in the number of markers tends to reach a plateau beyond a certain density. Another application of imputation is to increase the size of the training set with un-genotyped animals. This strategy can be particularly successful when a set of closely related individuals are genotyped. ----- Methods: Imputation on completely un-genotyped dams was performed using known genotypes from the sire of each dam, one offspring and the offspring’s sire. Two methods were applied based on either allele or haplotype frequencies to infer genotypes at ambiguous loci. Results of these methods and of two available software packages were compared. Quality of imputation under different population structures was assessed. The impact of using imputed dams to enlarge training sets on the accuracy of genomic predictions was evaluated for different populations, heritabilities and sizes of training sets. ----- Results: Imputation accuracy ranged from 0.52 to 0.93 depending on the population structure and the method used. The method that used allele frequencies performed better than the method based on haplotype frequencies. Accuracy of imputation was higher for populations with higher levels of linkage disequilibrium and with larger proportions of markers with more extreme allele frequencies. Inclusion of imputed dams in the training set increased the accuracy of genomic predictions. Gains in accuracy ranged from close to zero to 37.14%, depending on the simulated scenario. Generally, the larger the accuracy already obtained with the genotyped training set, the lower the increase in accuracy achieved by adding imputed dams. ----- Conclusions: Whenever a reference population resembling the family configuration considered here is available, imputation can be used to achieve an extra increase in accuracy of genomic predictions by enlarging the training set with completely un-genotyped dams. This strategy was shown to be particularly useful for populations with lower levels of linkage disequilibrium, for genomic selection on traits with low heritability, and for species or breeds for which the size of the reference population is limited.

Knowledge Building in Landscape Architecture

The objective of this study was to develop an internet-based seminar framework applicable for landscape architecture education. This process was accompanied by various aims. The basic expectation was to keep the main characteristics of landscape architecture education also in the online format. On top of that, four further objectives were anticipated: (1) training of competences for virtual team work, (2) fostering intercultural competence, (3) creation of equal opportunities for education through internet-based open access and (4) synergy effects and learning processes across institutional boundaries. This work started with the hypothesis that these four expected advantages would compensate for additional organisational efforts caused by the online delivery of the seminars and thus lead to a sustainable integration of this new learning mode into landscape architecture curricula. This rationale was followed by a presentation of four areas of knowledge to which the seminar development was directly related (1) landscape architecture as a subject and its pedagogy, (2) general learning theories, (3) developments in the ICT sector and (4) wider societal driving forces such as global citizenship and the increase of open educational resources. The research design took the shape of a pedagogical action research cycle. This approach was constructive: The author herself is teaching international landscape architecture students so that the model could directly be applied in practice. Seven online seminars were implemented in the period from 2008 to 2013 and this experience represents the core of this study. The seminars were conducted with varying themes while its pedagogy, organisation and the technological tools remained widely identical. The research design is further based on three levels of observation: (1) the seminar design on the basis of theory and methods from the learning sciences, in particular educational constructivism, (2) the seminar evaluation and (3) the evaluation of the seminars’ long term impact. The seminar model itself basically consists of four elements: (1) the taxonomy of learning objectives, (2) ICT tools and their application and pedagogy, (3) process models and (4) the case study framework. The seminar framework was followed by the presentation of the evaluation findings. The major findings of this study can be summed up as follows: Implementing online seminars across educational and national boundaries was possible both in term of organisation and technology. In particular, a high level of cultural diversity among the seminar participants has definitively been achieved. However, there were also obvious obstacles. These were primarily competing study commitments and incompatible schedules among the students attending from different academic programmes, partly even in different time zones. Both factors had negative impact on the individual and working group performances. With respect to the technical framework it can be concluded that the majority of the participants were able to use the tools either directly without any problem or after overcoming some smaller problems. Also the seminar wiki was intensively used for completing the seminar assignments. However, too less truly collaborative text production was observed which could be improved by changing the requirements for the collaborative task. Two different process models have been applied for guiding the collaboration of the small groups and both were in general successful. However, it needs to be said that even if the students were able to follow the collaborative task and to co-construct and compare case studies, most of them were not able to synthesize the knowledge they had compiled. This means that the area of consideration often remained on the level of the case and further reflections, generalisations and critique were largely missing. This shows that the seminar model needs to find better ways for triggering knowledge building and critical reflection. It was also suggested to have a more differentiated group building strategy in future seminars. A comparison of pre- and post seminar concept maps showed that an increase of factual and conceptual knowledge on the individual level was widely recognizable. Also the evaluation of the case studies (the major seminar output) revealed that the students have undergone developments of both the factual and the conceptual knowledge domain. Also their self-assessment with respect to individual learning development showed that the highest consensus was achieved in the field of subject-specific knowledge. The participants were much more doubtful with regard to the progress of generic competences such as analysis, communication and organisation. However, 50% of the participants confirmed that they perceived individual development on all competence areas the survey had asked for. Have the additional four targets been met? Concerning the competences for working in a virtual team it can be concluded that the vast majority was able to use the internet-based tools and to work with them in a target-oriented way. However, there were obvious differences regarding the intensity and activity of participation, both because of external and personal factors. A very positive aspect is the achievement of a high cultural diversity supporting the participants’ intercultural competence. Learning from group members was obviously a success factor for the working groups. Regarding the possibilities for better accessibility of educational opportunities it became clear that a significant number of participants were not able to go abroad during their studies because of financial or personal reasons. They confirmed that the online seminar was to some extent a compensation for not having been abroad for studying. Inter-institutional learning and synergy was achieved in so far that many teachers from different countries contributed with individual lectures. However, those teachers hardly ever followed more than one session. Therefore, the learning effect remained largely within the seminar learning group. Looking back at the research design it can be said that the pedagogical action research cycle was an appropriate and valuable approach allowing for strong interaction between theory and practice. However, some more external evaluation from peers in particular regarding the participants’ products would have been valuable.

eLearning im Sportstudium

In der gesamten Hochschullandschaft begleiten eLearning-Szenarien organisatorische Erneuerungsprozesse und stellen damit ein vielversprechendes Instrument zur Unterstützung und Verbesserung der klassischen Präsenzlehre dar. Davon ausgehend wurde von 2010 bis 2011 das Kasseler Sportspiel-Modell um die integrative Vermittlung der Einkontakt-Rückschlagspiele erweitert (Heyer, Albert, Scheid & Blömeke-Rumpf, 2011) und in einen modularisierten eLearning-Content, bestehend aus insgesamt 4 Modulen (17 Lernkurse, 171 Kursseiten, 73 Grafiken, 73 Videos, 38 Lernkontrollfragen), eingebunden. Dieser Content wurde im Rahmen einer Evaluationsstudie in Blended Learning Seminaren, welche die didaktischen Vorteile von Online- und Präsenzphasen zu einer Seminarform vereinen (Treumann, Ganguin & Arens, 2012), vergleichend zur klassischen Präsenzlehre im Sportstudium betrachtet. Die Studie gliedert sich in insgesamt drei Phasen: 1.) Pilotstudie am IfSS in Kassel (WS 2011/12; N=17, Lehramt), 2.) Hauptuntersuchung I am IfSS in Kassel (SS 2012; N=67, Lehramt) und 3.) Hauptuntersuchung II am IfS in Frankfurt a. M. (WS 2012/13; N=112, BA). Mittels varianzanalytischer Untersuchungsverfahren erfasst die Studie auf drei unterschiedlichen Qualitätsebenen folgende Aspekte der Lehr-Lernforschung: 1.) Ebene der Inputqualität: Bewertung der Seminarform (BS), 2.) Ebene der Prozessqualität: Motivation (SELLMO-ST), Lernstrategien (LIST) und computerbezogene Einstellung (FIDEC), 3.) Ebene der Outcomequalität: Lernleistung (Abschlusstest und Transferaufgabe). In der vergleichenden Betrachtung der beiden Hauptuntersuchungen erfolgt eine Gegenüberstellung von je einem Präsenzseminar zu zwei unterschiedlichen Varianten von Blended Learning Seminaren (BL-1, BL-2). Während der Online-Phasen bearbeiten die Sportstudierenden in BL-1 die Module in Lerngruppen. Die Teilnehmer in BL-2 führen in diesen Phasen zusätzlich persönliche Lerntagebücher. Dies soll zu einer vergleichsweise intensiveren Auseinandersetzung mit den Inhalten der Lernkurse sowie dem eigenen Lernprozess auf kognitiver und metakognitiver Ebene anregen (Hübner, Nückles & Renkl, 2007) und folglich zu besseren Ergebnissen auf den drei Qualitätsebenen führen. Die Ergebnisse der beiden Hauptuntersuchungen zeigen in der direkten, standortbezogenen Gegenüberstellung aller drei Seminarformen überwiegend keine statistisch signifikanten Unterschiede. Der erwartete positive Effekt durch die Einführung des Lerntagebuchs bleibt ebenfalls aus. Im standortübergreifenden Vergleich der Blended-Learning-Seminare ist bemerkenswert, dass die Probanden aus Frankfurt gegenüber ihrer Seminarform eine tendenziell kritischere Haltung einnehmen, was möglicherweise mit den vorherrschenden, unterschiedlichen Studiengängen – Lehramt und BA – korrespondiert. Zusammenfassend lässt sich somit für den untersuchten Bereich der Rückschlagspielvermittlung festhalten, dass Blended-Learning-Seminare eine qualitativ gleichwertige Alternative zur klassischen Präsenzlehre im Sportstudium darstellen.