Tissue internalisation is a key morphogenetic mechanism by which embryonic tissues generate complex internal organs and a number of studies of epithelia have outlined a general view of tissue internalisation. Here we have used quantitative live imaging and mutant analysis to determine whether similar mechanisms are responsible for internalisation in a tissue that apparently does not have a typical epithelial organisation – the zebrafish neural plate. We found that although zebrafish embryos begin neurulation without a conventional epithelium, medially located neural plate cells adopt strategies typical of epithelia in order to constrict their dorsal surface membrane during cell internalisation. Furthermore, we show that Myosin-II activity is a significant driver of this transient cell remodeling which also depends on Cdh2 (N-cadherin). Abrogation of Cdh2 results in defective Myosin-II distribution, mislocalised internalisation events and defective neural plate morphogenesis. Our work suggests Cdh2 coordinates Myosin-II dependent internalisation of the zebrafish neural plate.

This article explores the uses of sources in coverage of the COVID-19 pandemic in social media posts of mainstream news organizations in Brazil, Chile, Germany, Mexico, Spain, the U.K., and the U.S. Based on computational content analysis, our study analyzes the sources and actors present in more than 940,000 posts on COVID-19 published in the 227 Facebook, Instagram, and Twitter accounts of 78 sampled news outlets between January 1 and December 31 of 2020, comparing their relative importance across countries, across media platforms, and across time as the pandemic evolved in each country. The analysis shows the dominance of political sources across countries and platforms, particularly in Latin America, demonstrating a strong role of the state in constructing pandemic news and suggesting that mainstream news organizations' social media posts maintain a strong elite orientation. Health sources were also prominentconsistent with the defining role of biomedical authority in health coverage-, while significant diversity of sources, including citizen sources, emerged as the pandemic went on. Our results also revealed that the use of specific sources significantly varied over time. These variations tend to go hand in hand with specific global milestones of the pandemic.

Strengthening critical thinking abilities of citizens in the face of news published on the web represents a key challenge for education. Young citizens appear to be vulnerable in the face of poor quality news or those containing nonexplicit ideologies. In the field of data science, computational and statistical techniques have been developed to automatically collect and characterize online news media in real time. Nevertheless, there is still not a lot of interdisciplinary research on how to design data exploration platforms supporting an educational process of critical citizenship. This article explores this opportunity through a case study analyzing critical thinking ability of students when facing news dealing with the social mobilization “No+APF”. From data collected through 4 online exercises conducted by 75 secondary school students, 55 university students and 25 communication specialists, we investigate to what extent young citizens are able to classify news headlines and ideological orientation of news media outlets. We also question the influence of the media’s brand name and the subjectivity of each participant in regards to the social mobilization “No+APF”. The results underline the importance of group work, the influence of the brand name and the correlation between criticalthinking abilities and having a defined opinion. Fortalecer el pensamiento crítico de ciudadanos frente a noticias de Internet representa un desafío educativo clave. Los jóvenes ciudadanos parecen vulnerables frente a noticias de mala calidad u orientaciones ideológicas poco explícitas. Desde la ciencia de datos se desarrollan técnicas informáticas y estadísticas para recopilar prensa digital en tiempo real y caracterizarla automáticamente. Sin embargo, existe poca investigación interdisciplinar para diseñar plataformas de exploración de datos al servicio de un proceso educativo de ciudadanía crítica. Este artículo investiga esa oportunidad, mediante un estudio de caso en Chile que analiza la capacidad crítica del alumnado frente a noticias de un hecho social relevante: la movilización social «No+AFP». A partir de cuatro tareas en línea ?realizadas por 75 estudiantes de secundaria, 55 estudiantes universitarios y 25 especialistas en comunicación? preguntamos en qué medida los jóvenes son capaces de calificar titulares de prensa y orientaciones ideológicas de medios de comunicación. Por otra parte, analizamos la influencia de la marca del medio y de la subjetividad que, frente al movimiento social «No+AFP», imprime cada participante al pensamiento crítico. Los resultados obtenidos destacan la relevancia del trabajo en grupo, la influencia de la marca del medio de prensa y la correlación entre tener una opinión definida y la capacidad crítica.

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