@phdthesis{GuedesCorrea2009,
  author    = {Guedes Corr{\^e}a, Luiz Gustavo},
  title     = {Evolutionary and functional analysis of transcription factors controlling leaf development},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-40038},
  school      = {Universit{\"a}t Potsdam},
  year      = {2009},
  abstract  = {Leaves are the main photosynthetic organs of vascular plants, and leaf development is dependent on a proper control of gene expression. Transcription factors (TFs) are global regulators of gene expression that play essential roles in almost all biological processes among eukaryotes. This PhD project focused on the characterization of the sink-to-source transition of Arabidopsis leaves and on the analysis of TFs that play a role in early leaf development. The sink-to-source transition occurs when the young emerging leaves (net carbon importers) acquire a positive photosynthetic balance and start exporting photoassimilates. We have established molecular and physiological markers (i.e., CAB1 and CAB2 expression levels, AtSUC2 and AtCHoR expression patterns, chlorophyll and starch levels, and photosynthetic electron transport rates) to identify the starting point of the transition, especially because the sink-to-source is not accompanied by a visual phenotype in contrast to other developmental transitions, such as the mature-to-senescent transition of leaves. The sink-to-source transition can be divided into two different processes: one light dependent, related to photosynthesis and light responses; and one light independent or impaired, related to the changes in the vascular tissue that occur when leaves change from an import to an export mode. Furthermore, starch, but not sucrose, has been identified as one of the potential signalling molecules for this transition. The expression level of 1880 TFs during early leaf development was assessed by qRTPCR, and 153 TFs were found to exhibit differential expression levels of at least 5-fold. GRF, MYB and SRS are TF families, which are overrepresented among the differentially expressed TFs. Additionally, processes like cell identity acquisition, formation of the epidermis and leaf development are overrepresented among the differentially expressed TFs, which helps to validate the results obtained. Two of these TFs were further characterized. bZIP21 is a gene up-regulated during the sink-to-source and mature-to-senescent transitions. Its expression pattern in leaves overlaps with the one observed for AtCHoR, therefore it constitutes a good marker for the sink-to-source transition. Homozygous null mutants of bZIP21 could not be obtained, indicating that the total absence of bZIP21 function may be lethal to the plant. Phylogenetic analyses indicate that bZIP21 is an orthologue of Liguleless2 from maize. In these analyses, we identified that the whole set of bZIPs in plants originated from four founder genes, and that all bZIPs from angiosperms can be classified into 13 groups of homologues and 34 Possible Groups of Orthologues (PoGOs). bHLH64 is a gene highly expressed in early sink leaves, its expression is downregulated during the mature-to-senescent transition. Null mutants of bHLH64 are characterized by delayed bolting when compared to the wild-type; this indicates a possible delay in the sink-to-source transition or the retention of a juvenile identity. A third TF, Dof4, was also characterized. Dof4 is neither differentially expressed during the sink-to-source nor during the senescent-to-mature transition, but a null mutant of Dof4 develops bigger leaves than the wild-type and forms a greater number of siliques. The Dof4 null mutant has proven to be a good background for biomass accumulation analysis. Though not overrepresented during the sink-to-source transition, NAC transcription factors seem to contribute significantly to the mature-to-senescent transition. Twenty two NACs from Arabidopsis and 44 from rice are differentially expressed during late stages of leaf development. Phylogenetic analyses revealed that most of these NACs cluster into three big groups of homologues, indicating functional conservation between eudicots and monocots. To prove functional conservation of orthologues, the expression of ten NAC genes of barley was analysed. Eight of the ten NAC genes were found to be differentially expressed during senescence. The use of evolutionary approaches combined with functional studies is thus expected to support the transfer of current knowledge of gene control gained in model species to crops.},
  language  = {en}
}
@phdthesis{Jung2016,
  author    = {Jung, Janis Moritz},
  title     = {The role of dysfunctional peer relationships and academic failure in the development and progression of aggression},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-394477},
  school      = {Universit{\"a}t Potsdam},
  pages     = {163},
  year      = {2016},
  abstract  = {Background: Aggression is a severe behavioral problem that interferes with many developmental challenges individuals face in middle childhood and adolescence. Particularly in the peer and in the academic domain, aggression inhibits the individual from making important learning experiences that are predictive for a healthy transition into adulthood. Furthermore, the resulting developmental deficits have the propensity to feedback and to promote aggression at later developmental stages. The aim of the present PhD thesis was to investigate pathways and processes involved in the etiology of aggression by examining the interrelation between multiple developmental problems in the peer and in the academic domain. More specifically, the relevance of affiliation with deviant peers as a driving mechanism for the development of aggression, factors promoting the affiliation with deviant peers (social rejection; academic failure), and mechanisms by which affiliation with deviant peers leads to aggression (external locus of control) were investigated. Method: The research questions were addressed by three studies. Three data waves were available for the first study, the second and third study were based on two data waves. The first study specified pathways to antisocial behavior by investigating the temporal interrelation between social rejection, academic failure, and affiliation with deviant peers in a sample of 1,657 male and female children and adolescents aged between 6 and 15 years. The second study examined the role of external control beliefs as a potential mediator in the link between affiliation with deviant peers and aggression in a sample of 1,466 children and adolescents in the age of 9 to 19 years, employing a half-longitudinal design. The third study aimed to expand the findings of Study 1 and Study 2 by examining the differential predictivity of combinations of developmental risks for different functions of aggression, using a sample of 1,479 participants in the age between 9 and 19 years. First, profiles of social rejection, academic failure, and affiliation with deviant peers were identified, using latent profile analysis. Second, prospective pathways between risk-profiles and reactive and proactive aggression were investigated, using latent path analysis. Results: The first study revealed that antisocial behavior at T1 was associated with social rejection and academic failure at T2. Both mechanisms promoted affiliation with deviant peers at the same data wave, which predicted deviancy at T3. Furthermore, both an indirect pathway via social rejection and affiliation with deviant peers and an indirect pathway via academic failure and affiliation with deviant peers significantly mediated the link between antisocial behavior at the first and the third data wave. Additionally, the proposed pathways generalized across genders and different age groups. The second study yielded that external control beliefs significantly mediated the link between affiliation with deviant peers and aggression, with affiliation with deviant peers at T1 predicting external control beliefs at T2 and external control beliefs at T1 predicting aggressive behavior at T2. Again, the analyses provided no evidence for gender and age specific variations in the proposed pathways. In the third study, three distinct risk groups were identified, made up of a large non-risk group, with low scores on all risk measures, a group characterized by high scores on social rejection (SR group), and a group with the highest scores on measures of affiliation with deviant peers and academic failure (APAF group). Importantly, risk group membership was differentially associated with reactive and proactive aggression. Only membership in the SR group at T1 was associated with the development of reactive aggression at T2 and only membership in the APAF group at T1 predicted proactive aggression at T2. Additionally, proactive aggression at T1 predicted membership in the APAF group at T2, indicating a reciprocal relationship between both constructs. Conclusion: The results demonstrated that aggression causes severe behavioral deficits in social and academic domains which promote future aggression by increasing individuals' tendency to affiliate with deviant peers. The stimulation of external control beliefs provides an explanation for deviant peers' effect on the progression and intensification of aggression. Finally, multiple developmental risks were shown to co-occur within individuals and to be differentially predictive of reactive and proactive aggression. The findings of this doctoral dissertation have possible implications for the conceptualization of prevention and intervention programs aimed to reduce aggression in middle childhood and adolescence.},
  language  = {en}
}
@phdthesis{Kirsch2017,
  author    = {Kirsch, Fabian},
  title     = {Intrapersonal risk factors of aggressive behavior in childhood},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-407369},
  school      = {Universit{\"a}t Potsdam},
  pages     = {X, 182},
  year      = {2017},
  abstract  = {BACKGROUND: Aggressive behavior at an early age is linked to a broad range of psychosocial problems in later life. That is why risk factors of the occurrence and the development of aggression have been examined for a long time in psychological science. The present doctoral dissertation aims to expand this research by investigating risk factors in three intrapersonal domains using the prominent social-information processing approach by Crick and Dodge (1994) as a framework model. Anger regulation was examined as an affective, theory of mind as a cognitive, and physical attractiveness as an appearance-related developmental factor of aggression in middle childhood. An additional goal of this work was to develop and validate a behavioral observation assessment of anger regulation as past research lacked in ecologically valid measures of anger regulation that are applicable for longitudinal studies. METHODS: Three empirical studies address the aforementioned intrapersonal risk factors. In each study, data from the PIER-project were used, a three-wave-longitudinal study covering three years with a total sample size of 1,657 children in the age between 6 and 11 years (at the first measurement point). The central constructs were assessed via teacher-reports (aggression), behavioral observation (anger regulation), computer tests (theory of mind), and independent ratings (physical attractiveness). The predictive value of each proposed risk factor for the development of aggressive behavior was examined via structural equation modeling. RESULTS AND CONCLUSION: The newly developed behavioral observation measure was found to be a reliable and valid tool to assess anger regulation in middle childhood, but limited in capturing a full range of relevant regulation strategies. That might be the reason, why maladaptive anger regulation was not found to function as a risk factor of subsequent aggressive behavior. However, children's deficits in theory of mind and a low level in physical attractiveness significantly predicted later aggression. Problematic peer relationships were identified as underlying the link between low attractiveness and aggression. Thus, fostering children's skills in theory of mind and their ability to call existing beliefs about the nature of more versus less attractive individuals into question may be important starting points for the prevention of aggressive behavior in middle childhood.},
  language  = {en}
}
@phdthesis{LueckSchneider2007,
  author    = {L{\"u}ck-Schneider, Dagmar},
  title     = {Sportberufe im Kontext neuerer Sportentwicklungen : Analyse {\"o}ffentlicher Arbeitsmarktdaten (1997-2006)},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18420},
  school      = {Universit{\"a}t Potsdam},
  year      = {2007},
  abstract  = {Expansion und Pluralisierung des Sports lassen sich auch in {\"o}ffentlichen Arbeitsmarktstatistiken nachweisen. Dies zeigen Analysen {\"o}ffentlich eingesetzter Berufsverzeichnisse ab 1927 sowie Besch{\"a}ftigungsdaten, Arbeitslosenzahlen und Daten zu offen gemeldeten Stellen der Bundesagentur f{\"u}r Arbeit. Diese wurden f{\"u}r eine Vielzahl von Sportberufen ab 1997 erstmals ausgewertet. Die Bedeutung von Sportberufen in Berufsverzeichnissen ist gewachsen. Neue Berufe fanden bei entsprechender Arbeitsmarktbedeutung Eingang in die Verzeichnisse. Vereinzelt zeigen sich auch neuere Sporttrends. Ferner gab es seit 1999 eine außergew{\"o}hnliche Zunahme geringf{\"u}gig Besch{\"a}ftigter in allen betrachteten Berufsordnungen mit Sportberufen, teils auch eine Zunahme der sozialversicherungspflichtig Besch{\"a}ftigten. Fast ausnahmslos waren die Entwicklungen in beiden Besch{\"a}ftigungsarten in den untersuchten Berufsordnungen weit g{\"u}nstiger als im {\"u}bergeordneten Berufsumfeld. F{\"u}r den {\"u}berwiegenden Teil der Sportberufe ergab sich ein solches Ergebnis auch bei Betrachtung der Arbeitslosenzahlen, die von Anfang 1998 bis Ende 2004 ausgewertet wurden. Demgegen{\"u}ber wurden der Bundesagentur f{\"u}r Arbeit f{\"u}r fast alle sportbezogenen Berufsklassen 2006 weniger offene ungef{\"o}rderte Stellen gemeldet als noch 2000. Diese Entwicklung war jedoch nicht ausschließlich f{\"u}r die Berufsklassen im Sport zu beobachten. So sprechen die Ergebnisse zumindest f{\"u}r eine vergleichsweise gute Arbeitsmarktentwicklung in den meisten untersuchten Sportberufen. Die große Zunahme geringf{\"u}giger Besch{\"a}ftigung zeigt aber, dass hier vor allem keine als Haupterwerbsquelle geeigneten Besch{\"a}ftigungen entstanden sind. Dies reduziert zugleich die Chancen, mit diesen Berufen Arbeitslosigkeit zu reduzieren.},
  language  = {de}
}