Trait variation among heterospecific and conspecific organisms may substantially affect community and food web dynamics. While the relevance of competition and feeding traits have been widely studied for different consumer species, studies on intraspecific differences are more scarce, partly owing to difficulties in distinguishing different clones of the same species. Here, we investigate how intraspecific trait variation affects the competition between the freshwater ciliates Euplotes octocarinatus and Coleps hirtus in a nitrogen-limited chemostat system. The ciliates competed for the microalgae Cryptomonas sp. (Cry) and Navicula pelliculosa (Nav), and the bacteria present in the cultures over a period of 33 days. We used monoclonal Euplotes and three different Coleps clones (Col 1, Col 2, and Col 3) in the experiment that could be distinguished by a newly developed rDNA-based molecular assay based on the internal transcribed spacer (ITS) regions. While Euplotes feeds on Cry and on bacteria, the Coleps clones cannot survive on bacteria alone but feed on both Cry and Nav with clone-specific rates. Experimental treatments comprised two-species mixtures of Euplotes and one or all of the three different Coleps clones, respectively. We found intraspecific variation in the traits "selectivity" and "maximum ingestion rate" for the different algae to significantly affect the competitive outcome between the two ciliate species. As Nav quickly escaped top-down control and likely reached a state of low food quality, ciliate competition was strongly determined by the preference of different Coleps clones for Cry as opposed to feeding on Nav. In addition, the ability of Euplotes to use bacteria as an alternative food source strengthened its persistence once Cry was depleted. Hence, trait variation at both trophic levels codetermined the population dynamics and the outcome of species competition.

The purpose of this thesis was to investigate the developmental dynamics between interest, motivation, and learning strategy use during physics learning. The target population was lower secondary school students from a developing country, given that there is hardly in research that studies the above domain-specific concepts in the context of developing countries. The aim was addressed in four parts. The first part of the study was guided by three objectives: (a) to adapt and validate the Science Motivation Questionnaire (SMQ-II) for the Ugandan context; (b) to examine whether there are significant differences in motivation for learning Physics with respect to students’ gender; and (c) to establish the extent to which students’ interest predicts their motivation to learn Physics. Being a pilot study, the sample comprised 374 randomly selected students from five schools in central Uganda who responded to anonymous questionnaires that included scales from the SMQ-II and the Individual Interest Questionnaire. Data were analysed using confirmatory factor analyses, t-tests and structural equation modelling in SPSS-25 and Mplus-8. The five-factor model solution of the SMQ-II fitted adequately with the study data, with deletion of one item. The modified SMQ-II exhibited invariant factor loadings and intercepts (i.e., strong measurement invariance) when administered to boys and girls. Furthermore, on assessing whether motivation for learning Physics varied with gender, no significant differences were noted. On assessing the predictive effects of individual interest on students’ motivation, individual interest significantly predicted all motivational constructs, with stronger predictive strength on students’ self-efficacy and self-determination in learning Physics. In the second part whilst using comprised 934 Grade 9 students from eight secondary schools in Uganda, Latent profile analysis (LPA) - a person-centred approach was used to investigate motivation patterns that exist in lower secondary school students during physics learning. A three-step approach to LPA was used to answer three research questions: RQ1, which profiles of secondary school students exist with regards to their motivation for Physics learning; RQ2, are there differences in students’ cognitive learning strategies in the identified profiles; and RQ3, does students’ gender, attitudes, and individual interest predict membership in these profiles? Six motivational profiles were identified: (i) low-quantity motivation profile (101 students; 10.8%); (ii) moderate-quantity motivation profile (246 students; 26.3%); (iii) high-quantity motivation profile (365 students; 39.1%); (iv) primarily intrinsically motivated profile (60 students,6.4%); (v) mostly extrinsically motivated profile (88 students, 9.4%); and (vi) grade-introjected profile (74 students, 7.9%). Low-quantity and grade introjected motivated students mostly used surface learning strategies whilst the high-quantity and primarily intrinsically motivated students used deep learning strategies. On examining the predictive effect of gender, individual interest, and students’ attitudes on the profile membership, unlike gender, individual interest and students’ attitudes towards Physics learning strongly predicted profile membership. In the third part of the study, the occurrence of different secondary school learner profiles depending on their various combinations of cognitive and metacognitive learning strategy use, as well as their differences in perceived autonomy support, intrinsic motivation, and gender was examined. Data were collected from 576 9th grade student. Four learner profiles were identified: competent strategy user, struggling user, surface-level learner, and deep-level learner profiles. Gender differences were noted in students’ use of elaboration and organization strategies to learn Physics, in favour of girls. In terms of profile memberships, significant differences in gender, intrinsic motivation and perceived autonomy support were also noted. Girls were 2.4 - 2.7 times more likely than boys to be members of the competent strategy user and surface-level learner profiles. Additionally, higher levels of intrinsic motivation predicted an increased likelihood membership into the deep-level learner profile, whilst higher levels of perceived teacher autonomy predicted an increased likelihood membership into the competent strategy user profile as compared to other profiles. Lastly, in the fourth part, changes in secondary school students’ physics motivation and cognitive learning strategies use during physics learning across time were examined. Two waves of data were collected from initially 954 9th students through to their 10th grade. A three-step approach to Latent transition analysis was used. Generally, students’ motivation decreased from 9th to 10th grade. Qualitative students’ motivation profiles indicated strong with-in person stability whilst the quantitative profiles were relatively less stable. Mostly, students moved from the high quantity motivation profile to the extrinsically motivated profiles. On the other hand, the cognitive learning strategies use profiles were moderately stable; with higher with-in person stability in the deep-level learner profile. None of the struggling users and surface-level learners transitioned into the deep-level learners’ profile. Additionally, students who perceived increased support for autonomy from their teachers had higher membership likelihood into the competent users’ profiles whilst those with an increase in individual interest score had higher membership likelihood into the deep-level learner profile.

(40)A/Ar-39 step-heating of mica and amphibole megacrysts from hauyne-bearing olivine melilitite scoria/tephra from the Zelezna hurka yielded a 435 +/- 108 ka isotope correlation age for phlogopite and a more imprecise 1.55 Ma total gas age of the kaersutite megacryst. The amphibole megacrysts may constitute the first, and the younger phlogopite megacrysts the later phase of mafic, hydrous melilitic magma crystallization. It cannot be ruled out that the amphibole megacrysts are petrogenetically unrelated to tephra and phlogopite megacrysts and were derived from mantle xenoliths or disaggregated older, deep crustal pegmatites. This is in line both with the rarity of amphibole at Zelezna hurka and with the observed signs of magmatic resorption at the edges of amphibole crystals.

Wo steht die Entrepreneurship-Forschung aktuell und welchen Nutzen stiftet sie für die Gründungspraxis? Das Buch gibt einen repräsentativen Querschnitt durch das breite Spektrum des Entrepreneuerships und zeigt den aktuellen State-of-the-Art auf. Schwerpunktthemen sind: - Entrepreneur-Persönlichkeit - Unternehmerische Organisation - Spezifische Erscheinungsformen des Entrepreneurships - Systemische Betrachtung des Entrepreneurships - Entrepreneurial Ecosystem - Entrepreneurial Education Das Buchprojekt versteht sich als Beitrag zum Theorie-Praxis-Transfer und richtet sich neben Wissenschaftlern auch an Entrepreneure in der Praxis.