Comparative developmental osteology of the seahorse skeleton reveals heterochrony amongst Hippocampus sp. and progressive caudal fin loss

Background: Seahorses are well known for their highly derived head shape, prehensile tail and armoured body. They belong to the family of teleosts known as Syngnathidae, which also includes the pipefishes, pipehorses and seadragons. Very few studies have investigated the development of the skeleton of seahorses because larvae are extremely difficult to obtain in the wild and breeding in captivity is rarely successful. Here we compare the developmental osteology of Hippocampus reidi over an ontogenetic series spanning the first 93 days after release from the brood pouch to that of a smaller series of Hippocampus; namely H. subelongatus. Results: We compare the osteology in these two species over growth to the published description of the dwarf species, H. zosterae. We show that ossification onset in H. subelongatus is earlier than in H. reidi, despite similar sizes at parturition. Interestingly, the timing of development of the bony skeleton in H. zosterae is similar to that of the larger species, H. subelongatus. Furthermore, we show that the growth rate of all three species is similar up until about 30 days post pouch release. From this stage onwards in the life history, the size of the dwarf species H. zosterae remains relatively constant whilst the other two species continue growing with an accelerated growth phase. Conclusion: This data together with a phylogenetic assessment suggests that there has been a heterochronic shift (a delay) in the timing of ossification in H. reidi and accelerated bonedevelopment in H. zosterae. That is, H. zosterae is not a developmentally truncated dwarf species but rather a smaller version of its larger ancestor, "a proportioned dwarf" species. Furthermore, we show that caudal fin loss is incomplete in Hippocampus seahorses. This study shows that these three species of Hippocampus seahorses have evolved (either directly or indirectly) different osteogenic strategies over the last 20-30 million years of seahorse evolution

Induction of the retinal pigment epithelium of the chicken embryonic eye

During development of the eye, invagination of the optic cup gives rise to a double layered neuroepithelium, part of which differentiates into the retinal pigment epithelium (RPE). The molecular mechanisms which control differentiation of the RPE are not known. The present study was undertaken to determine 1) when induction of the RPE has occurred in chicken embryos and 2) to investigate whether contact with the presumptive neural retina (NR) is required for RPE differentiation. In order to investigate when RPE induction has occurred, early expression of two genes involved in pigmentation were investigated. Digoxigenin-labeled tyrosinase and tyrosinaserelated protein-2 (TRP-2) riboprobes were synthesised and used in ISH reactions on embryonic eye tissue. Tyrosinase transcripts were first detected at stage 19.5 (70-71 hours) and TRP-2 transcripts were detected a few hours earlier at stage 18.5 (67-69 hours) of embryonic development. These results indicate that induction has occurred by stage 18.5, approximately ten hours before distinct granules are visible in the RPE. The tyrosinase and TRP-2 transcripts were always localised first in the optical axis of the eye in the region where pigment granules are first present. This indicates that differentiation of the RPE proceeds from the optical axis of the eye cup outwards towards the periphery and that induction of the RPE may also proceed in this direction. To determine whether the presumptive NR is required for RPE induction, synthetic barriers were inserted into the uninvaginated optic vesicle of chicken embryos at stage 11 (40-45 hours) of development. The embryos were cultured in vitro until the optic vesicle had invaginated and sectioned to locate the barrier. Results suggest that contact with the presumptive NR may not be necessary for RPE induction

Automatic road network extraction in suburban areas from high resolution aerial images

In this paper a road network extraction algorithm for suburban areas is presented. The algorithm uses colour infrared (CIR) images and digital surface models (DSM). The CIR data allow a good separation between vegetation and roads. The image is first segmented in two steps: an initial segmentation using the normalized cuts algorithm and a subsequent grouping of the segments. Road parts are extracted from the segments and then first connected locally to form subgraphs, because roads are often not extracted as a whole due to disturbances in their appearance. Subgraphs can contain several branches, which are resolved by a subsequent optimisation. The optimisation uses criteria describing the relations between the road parts as well as context objects such as trees, vehicles and buildings. The resulting road strings, represented by their centre lines, are then connected to a road network by searching for junctions at the ends of the roads. Small isolated roads are eliminated because they are likely to be false extractions. Results are presented for three image subsets coming from two different data sets, and a quantitative analysis of the completeness and correctness is shown from nine image subsets from the two data sets. The results show that the approach is suitable for the extraction of roads in suburban areas from aerial images

Editorial — Business and Human Rights: Taking Stock of Trends in International Governance and Domestic Litigation

Business and Human Rights: Taking Stock of Trends in International Governance and Domestic Litigation (Editorial

A Social Network Approach to Blogs: Improving Digital Collaborative Learning

Blogs as digital collaboration tools are promising resources in higher education to impart knowledge, enhance collaboration and social interaction among students and thus, to increase their success. Despite the widespread use of blogs, little is known about blogs’ impact on students’ social networks and its effect on learning success. Therefore, based on a social network perspective, we empirically assess the change in the social network of 51 blog users. We are among the first to investigate the influence of the social network’s characteristics on students\u27 subjectively perceived performance and access to knowledge within a blog-learning environment. We find evidence that blogs significantly increase the students\u27 social networks, but are primarily a medium for reinforcing what the student has learned rather than influencing performance related outcomes. Our results yield important practical and theoretical recommendations on how blogs can be used to enhance students’ social networks and in turn increase their success

What Do I Do in a World of Artificial Intelligence? Investigating the Impact of Substitutive Decision-Making AI Systems on Employees’ Professional Role Identity

Artificial intelligence (AI) systems in the workplace increasingly substitute for employees’ tasks, responsibilities, and decision-making. Consequently, employees must relinquish core activities of their work processes without the ability to interact with the AI system (e.g., to influence decision-making processes or adapt or overrule decision-making outcomes). To deepen our understanding of how substitutive decision-making AI systems affect employees’ professional role identity and how employees adapt their identity in response to the system, we conducted an in-depth case study of a company in the area of loan consulting. We qualitatively analyzed more than 60 interviews with employees and managers. Our research contributes to the literature on IS and identity by disclosing mechanisms through which employees strengthen and protect their professional role identity despite being unable to directly interact with the AI system. Further, we highlight the boundary conditions for introducing an AI system and contribute to the body of empirical research on the potential downsides of AI

Algorithmic Technologies as Threat to Who We Are: The Effect an IT Identity Threat has on Employees\u27 Work Engagement

Organizations’ introduction of algorithmic technologies fundamentally affects employees’ work processes, tasks, and responsibilities in organizations. Employees often find their professional identities threatened by the introduction of IT (a phenomenon labeled as IT Identity Threat). While prior studies have examined which mechanisms employees use to deal with such a perceived threat, it remains unclear how an IT Identity Threat affects employees’ work attitude in response to advanced IT such as algorithmic technologies. Employees’ work attitude is a recognized antecedent to workers’ well-being or performance. Based on a mixed-method study in the banking industry, our study reveals that an IT Identity Threat negatively affects employees’ work engagement. Further, our study uncovers how this effect comes about by showing that an IT Identity Threat decreases employees’ perceived autonomy and experienced responsibility for their work outcomes. Overall, both factors contribute to a negative relationship between an IT Identity Threat and employees’ work engagement

A qualitative analysis of the major curriculum reform of medical studies at the Charité applying the sociological perspective of Pierre Bourdieu

Hintergrund: Curriculumreformen sind essenziell für Universitäten, um zukünftige Mediziner*innen bestmöglich auf die klinische Praxis, den fortschreitenden Erkenntnisgewinn der Medizin und die steigenden Anforderungen vorzubereiten. Reformen sind jedoch komplexe Prozesse und bergen zahlreiche Konflikte wie Machtkämpfe und Widerstand unter den Beteiligten. In dieser Arbeit wird am Beispiel der umfassenden Reform des Medizinstudiums an der Charité – Universitätsmedizin Berlin untersucht, welche sozialen Mechanismen innerhalb einer Reform wirken. Als theoretisches Rahmenwerk für diese Studie dient Pierre Bourdieus Theorie der sozialen Praxis. Diese beschreibt soziale Felder, in denen Individuen mit unterschiedlichem Habitus soziale Positionen einnehmen, welche durch ökonomisches, kulturelles oder soziales Kapital definiert werden (Bourdieu 1986). Methode: An der Charité wurde von 2000 bis 2016 in einer umfassenden Reform der traditionelle, fächerbasierte Regelstudiengang Medizin in einen integrierten, kompetenzbasierten und Outcome-orientierten Modellstudiengang reformiert. Ab 2013 wurde eine Reform der Reform notwendig, welche von einem Curriculumplanungskomitee durchgeführt wurde. Mit 13 Mitgliedern aller drei Interessengruppen dieses Planungskomitees (Einrichtungs- und Studierendenvertreter*innen, Curriculumentwickler*innen) wurden qualitative Interviews über ihre Erfahrungen geführt. Die Interviewtranskriptionen wurden unter Anwendung der zusammenfassenden und strukturierenden Inhaltsanalyse nach Mayring (2015) in einem induktiven-deduktiven Vorgang ausgewertet. Ergebnisse: Mit der Perspektive von Bourdieus Theorie konnten Machtstrukturen innerhalb des Planungskomittees durch die Identifikation verschiedener sozialer Positionen von Beteiligten und die Verteilung von Kapital sichtbar gemacht werden. Die konfliktreichen Diskussionen zwischen den Interessengruppen wurden vordergründig auf inhaltlicher Ebene über Curriculumsinhalte geführt. Hintergründig wurden jedoch hochschulpolitische Kämpfe für und mit unterschiedlichen Formen von Kapital ausgetragen, um soziale Positionen innerhalb der medizinischen Fakultät zu erhalten und auszubauen. Die Reform ging mit einem Machtverlust für die Einrichtungsvertreter*innen einher, welche von einer ständigen Angst begleitet waren, Mitarbeiter*innenstellen zu verlieren. Die Studierendenvertreter*innen, als treibende Kraft für die Reform, konnten mit dem Einsatz von sozialem und kulturellem Kapital ihre soziale Position verbessern. Der Habitus der Medizinstudierenden war geprägt von Enthusiasmus für den neuen Studiengang, um eine bestmögliche Ausbildung für ihre spätere ärztliche Tätigkeit zu bekommen, während der Habitus der Einrichtungsvertreter*innen mehr auf die klinische Leistung als auf die Lehre von Studierenden ausgerichtet war. Schlussfolgerung: Eine Curriculumreform führt zu einer Verschiebung und Aushandlung von manifestierten sozialen Strukturen und Machtverhältnissen innerhalb von medizinischen Fakultäten. Reformprozesse gehen weit über die Planungs- und Implementationsphase von veränderten Lehr- und Lerninhalten hinaus und bedeuten zudem einen radikalen Wandel von Denkweisen und Einstellungen der Beteiligten einer medizinischen Fakultät.Background: Curriculum reform is essential for medical schools in order to prepare future physicians in the best possible way for their clinical practice and the increasing demands associated with the rapidly advancing medical knowledge. However, reforms are complex processes and involve numerous conflicts such as power struggles and resistance among the stakeholders of different institutions. This work examines the social mechanisms that occur within a curriculum reform on basis of the comprehensive curriculum reform at the Charité – Universitätsmedizin Berlin. For this study, Pierre Bourdieu's theory of social practice serves as the theoretical framework. It describes social fields in which individuals with different habitus occupy social positions that are defined by their economic, cultural or social capital (Bourdieu 1986). Methods: At the Charité, the traditional, discipline-based curriculum was reformed into an integrated, competency-based and outcome-oriented medical program from 2000 to 2016. Starting in 2013, a reform of the reform became necessary, which was carried out by a curriculum planning committee. Qualitative interviews were conducted with 13 members of this planning committee about their experiences (department representatives, student representatives, curriculum staff management representatives). The interview transcriptions were analyzed using the summarizing and structuring content analysis according to Mayring (2015) in an inductive-deductive approach. Results: Using the perspective of Bourdieu's theory, power struggles within the planning committee could be made visible through the identification of different social positions and the distribution of capital. On the surface, the conflicting discussions between the interest groups were about curricular content. Behind the scenes, members of the committee fought for and with different forms of capital in order to maintain and increase their social positions within medical school. The reform was accompanied by a loss of power for the department representatives, who had a constant fear of losing staff positions. The student representatives, as the driving force of the reform, were able to improve their social position by using social and cultural capital. The habitus of medical students was characterized by enthusiasm for the new curriculum in order to receive the best possible training for their future clinical practice, while department representatives preferred clinical performance over teaching students. Conclusions: Curriculum reform leads to a shift and negotiation of manifested social structures and power relations within medical schools. Reform processes go far beyond the planning and implementation phase of changed teaching and learning content and involves a radical shift in the mindsets and attitudes of those involved in a medical school