Developmental Transitions

Insect metamorphosis has been a classic model to understand the role of hormones in growth and timing of developmental transitions. In addition to hormones, transitions in some species are regulated by genetic programs, such as the heterochronic gene network discovered in C. elegans. However, the functional link between hormones and heterochronic genes is not clear. The heterochronic gene lin-28 is involved in the maintenance of stem cells, growth and developmental timing in vertebrates. In this work, we used gain-of-function and loss-of-function experiments to study the role of Lin-28 in larval growth and the timing of metamorphosis of Drosophila melanogaster. During the late third instar stage, Lin-28 is mainly expressed in neurons of the central nervous system and in the intestine. Loss-of-function lin-28 mutant larvae are smaller and the larval-topupal transition is accelerated. This faster transition correlates with increased levels of ecdysone direct target genes such as Broad-Complex (BR-C) and Ecdysone Receptor (EcR). Overexpression of Lin-28 does not affect the timing of pupariation but most animals are not able to eclose, suggesting defects in metamorphosis. Overexpression of human Lin-28 results in delayed pupariation and the death of animals during metamorphosis. Altogether, these results suggest that Lin-28 is involved in the control of growth during larval development and in the timing and progression of metamorphosis.

Nas sociedades ocidentais contemporâneas, parece assistir-se a um agravamento do sentimento de incerteza, a uma diminuição da coesão social e, simultaneamente, a um aumento das alternativas vocacionais e das possibilidades de escolha. O objetivo da investigação cujo projeto aqui se apresenta tem que ver, então, com a forma como os adultos licenciados (ou com qualificação superior) se percecionam face a situações de não emprego, ou seja, quando não conseguem obter emprego no seu nível e/ou área de formação. Para além disso, importará compreender quais as estratégias implementadas pelos sujeitos para lidar com essas transições desenvolvimentais. Pensa-se que este trabalho se reveste de pertinência científica, porquanto é um problema pouco estudado em Portugal, e social, também, pelo facto de se referir a um conjunto significativo de desempregados, a que acrescem os números de "inativos" (disponíveis e desencorajados) e do subemprego (visível e percebido) não contabilizados n...

This study investigates how the transition toward self-direction is experienced and facilitated in 2 semester-long courses in teacher education degree programs and the differences in such a transition for freshman and master's students. The thematic analysis of the written self-assessments of 8 illustrative examples enabled the detection of (a) students' initial upset in the face of demands for internal authority; (b) the support of the teacher and peers in managing that upset; and (c) the students' shift toward more complex conceptions of learning and teaching, including evidence of increasing selfdirection. These findings shed light on the potential of intentionally designed learning contexts for promoting students' epistemological development. The similarities found between freshman and master's students' experiences when managing the demands of internal authority emphasize the underutilization of the most extended teaching practices in higher education.

Insect metamorphosis has been a classic model to understand the role of hormones in growth and timing of developmental transitions. In addition to hormones, transitions in some species are regulated by genetic programs, such as the heterochronic gene network discovered in C. elegans. However, the functional link between hormones and heterochronic genes is not clear. The heterochronic gene lin-28 is involved in the maintenance of stem cells, growth and developmental timing in vertebrates. In this work, we used gain-of-function and loss-of-function experiments to study the role of Lin-28 in larval growth and the timing of metamorphosis of Drosophila melanogaster. During the late third instar stage, Lin-28 is mainly expressed in neurons of the central nervous system and in the intestine. Loss-of-function lin-28 mutant larvae are smaller and the larval-topupal transition is accelerated. This faster transition correlates with increased levels of ecdysone direct target genes such as Broad-Complex (BR-C) and Ecdysone Receptor (EcR). Overexpression of Lin-28 does not affect the timing of pupariation but most animals are not able to eclose, suggesting defects in metamorphosis. Overexpression of human Lin-28 results in delayed pupariation and the death of animals during metamorphosis. Altogether, these results suggest that Lin-28 is involved in the control of growth during larval development and in the timing and progression of metamorphosis.

The technological, commercial and sexual revolution of the past century paved the way for an emerging youth movement that is in the 21st Century, especially in developed countries, an exciting and prolonged developmental stage presenting numerous opportunities, freedoms, but also challenges and risks that were unheard of to their parents and grandparents. The carefree life, captured in the words ‘young, wild and free’ are in part a reflection of this continued transitional feature of young people’s role and engagement in society and the postponement of more serious commitments, such as marriage, viewed as closing doors and spontaneity.

This study aims to look at characteristics that make the transitional period between adolescence and emerging adulthood special or ‘wild’, and delves into risks and opportunities predominant in this protracted developmental stage.

This study investigates how the transition toward self-direction is experienced and facilitated in 2 semester-long courses in teacher education degree programs and the differences in such a transition for freshman and master’s students. The thematic analysis of the written self-assessments of 8 illustrative examples enabled the detection of (a) students’ initial upset in the face of demands for internal authority; (b) the support of the teacher and peers in managing that upset; and (c) the students’ shift toward more complex conceptions of learning and teaching, including evidence of increasing self-direction. These findings shed light on the potential of intentionally designed learning contexts for promoting students’ epistemological development. The similarities found between freshman and master’s students’ experiences when managing the demands of internal authority emphasize the underutilization of the most extended teaching practices in higher education.

We proceed to present in this chapter an active and experiential teaching approach based in the creation of "collaborative contexts". This collaborative approach has been experienced and developed through different educational scenarios from Bachelor's to Doctorate's degree studies since 2002. Going beyond the application of cooperative techniques we propose the convenience of reflecting about the kind of context that is created all through one course between all the involved participants: teacher and students as a whole. According to this we reflect and present evidence concerning the following topics: developmental demands for teachers and students participating in a collaborative experience; key social skills (communication, managing conflicts and leadership processes); interdisciplinary practices with the coordination of several subjects; coherent evaluation practices promoting learning instead of control processes; competence promotion instead of just content elaboration; optional instead of compulsory contexts; useful connecting processes (the McGuffin project ); real practices instead of faked or simulated exercises and finally integration of new virtual technologies such as wikis, blogs and forums to support the process. After exploring these topics we conclude proposing a typical sequence useful to promote this kind of collaborative approach.