The relationship between cell size and cell fate in Volvox carteri

In Volvox carteri development, visibly asymmetric cleavage divisions set apart large embryonic cells that will become asexual reproductive cells (gonidia) from smaller cells that will produce terminally differentiated somatic cells. Three mechanisms have been proposed to explain how asymmetric division leads to cell specification in Volvox: (a) by a direct effect of cell size (or a property derived from it) on cell specification, (b) by segregation of a cytoplasmic factor resembling germ plasm into large cells, and (c) by a combined effect of differences in cytoplasmic quality and cytoplasmic quantity. In this study a variety of V. carteri embryos with genetically and experimentally altered patterns of development were examined in an attempt to distinguish among these hypotheses. No evidence was found for regionally specialized cytoplasm that is essential for gonidial specification. In all cases studied, cells with a diameter > approximately 8 microns at the end of cleavage--no matter where or how these cells had been produced in the embryo--developed as gonidia. Instructive observations in this regard were obtained by three different experimental interventions. (a) When heat shock was used to interrupt cleavage prematurely, so that presumptive somatic cells were left much larger than they normally would be at the end of cleavage, most cells differentiated as gonidia. This result was obtained both with wild-type embryos that had already divided asymmetrically (and should have segregated any cytoplasmic determinants involved in cell specification) and with embryos of a mutant that normally produces only somatic cells. (b) When individual wild-type blastomeres were isolated at the 16-cell stage, both the anterior blastomeres that normally produce two gonidia each and the posterior blastomeres that normally produce no gonidia underwent modified cleavage patterns and each produced an average of one large cell that developed as a gonidium. (c) When large cells were created microsurgically in a region of the embryo that normally makes only somatic cells, these large cells became gonidia. These data argue strongly for a central role of cell size in germ/soma specification in Volvox carteri, but leave open the question of how differences in cell size are actually transduced into differences in gene expression

A State Observer Design for Simultaneous Estimation of Charge State and Crossover in Self-Discharging Disproportionation Redox Flow Batteries

This paper presents an augmented state observer design for the simultaneous estimation of charge state and crossover flux in disproportionation redox flow batteries, which exhibits exponential estimation error convergence to a bounded residual set. The crossover flux of vanadium through the porous separator is considered as an unknown function of the battery states, model-approximated as the output of a persistently excited linear system. This parametric model and the simple isothermal lumped parameter model of the battery are combined to form an augmented space state representation suitable for the observer design, which is carried out via Lyapunov stability theory including the error-uncertainty involved in the approximation of the crossover flux. The observer gain is calculated by solving a polytopic linear matrix inequality problem via convex optimization. The performance of this design is evaluated with a laboratory flow battery prototype undergoing self-discharge.Comment: arXiv admin note: text overlap with arXiv:1903.0407

Con la escuela en el cuerpo, cuerpos escolarizados: la construccion de identidades inter/nacionales en la sociedad post-disciplinaria

From the 1880s until the present schooling practices have institutionalised That focus on the social regulation and normalization of the body. To Illustrate and elaborate this argument, I will seek to show how the regulation of the body in space and in time worked in schools in the mid to late 19th century in Australia and Britain. I will next show how school physical training, sport and medical inspection were developed as a cluster of specialised highly corporeal practices during the first half of the 20th century. I will then even though there suggest that have been attempts during the 20th century to challenge schooling as an institution, the basic structure of the school as a site of corporeal regulation remained and normalization has more or less intact to the present. Finally, I will speculate about the ways in contemporary processes which may construct of schooling embodied inter / national identities in the first decade of the 21st century

'Maculinisation', 'sportification' and 'academicisation' in the men's colleges : a case study of the Carnegie curriculum

The dominant narrative flowing through much of the historical writing on physical education is that the men and women existed, as the 19th century ideology had it, in ‘separate spheres’ (Rosenburg 1982). In England, as Fletcher (1984) argued, women led the field from the late 19th century until the middle of the 20th century. When the men began to arrive on the scene in large numbers in the post WW2 period, in earnest from the late 1940s on, there began a ‘gender-war’ in physical education which the women, so the narrative tells us, eventually lost. But in fact professional training for men in physical education began much earlier than the 1950s and the input of men into the physical education profession starts even earlier than this date. Dunfermline College accepted male students from the 1910s, the Scottish School of Physical Education based in Glasgow opened its doors in 1932, while Carnegie Physical Training College in Leeds had its first intake of students in 1934, with Loughborough College close behind in 1936. Like those for the women, the colleges for men were initially strictly single-sex, seemingly confirming the separate spheres aspect of the narrative

A defining time for physical education futures? Exploring the legacy of Fritz Duras

This paper explores the legacy of Dr Fritz Duras in order to address the issue of whether the implementation of a new curriculum for health and physical education in Australia represents a defining time for the subject. Dr Duras was Director of the first physical education teacher education course at the University of Melbourne during an earlier defining time, when a new sports and games-based form of physical education was created to replace an older drilling and exercising form of physical training. The paper interrogates what we might mean by the notion of a defining time before investigating key events in the history of Australian physical education between the 1940s and the 1970s. It considers the role of Australian Council for Health, Physical Education and Recreation and individual activism in relation to the new curriculum. The paper concludes with a detailed discussion of five things the new curriculum must do in order for it to build further on the legacy of Dr Duras and create a new defining time for the subject in Australian schools

Precarity and Physical Education

This paper explores the concept of precarity and its relevance for physical education. I argue that precarity is closely related to neoliberal practices of privatization and free-markets, and that these practices have been exerting an influence on physical education for some time. As the digitization of education gains momentum, I suggest physical educators cannot afford to be complacent about their future place in the school curriculum. Nor can they ignore the rise of precarity and its detrimental influence on the young people they teach. Physical educators have long argued that they make a contribution to young people’s affective development, in terms of their motivation, resilience, cooperation and interest. Arguably, in the face of rising precarity and its ill effects on young people’s mental health and wellbeing, there is a need for physical educators to develop ‘pedagogies of affect’, that take affective learning as its main concern. Teachers themselves may become victims of precarity as education in the Global North, once regarded as a mainly public good, increasingly is privatised. The neoliberal imperative to maximise profit at whatever cost to human wellbeing could result in teachers’ working conditions deteriorating, further adding to what is for many an already high stress occupation. I conclude that we may need to rethink the critical pedagogy project in an age of precarity

A new critical pedagogy for physical education in turbulent times : what are the possibilities?

In his book On Critical Pedagogy, Henry Giroux (2011) writes about the possibilities for critical pedagogy 'in dark times'. Giroux argues that "politics is central to any notion of pedagogy that takes as its primary project the necessity to provide conditions that expand the capacities of students to think critically and teach them how to take risks in a socially responsible way" (p. 6). The challenge for critical pedagogy is to address the changes that have taken place in politics and in society more broadly in the past 50 years, since the earliest appearance of this concept inspired by the work of activist scholars such Paolo Friere (1996/1968) among others. Recent social analyses have disorganised and undermined standard conceptions of political divisions around Left and Right, and traditional strategies of resistance to oppression and stock critical pedagogy aspirations such as empowerment and emancipation. A particular focus of this work has been social injustice (Dorling, 2010), inequality (Atkinson, 2015; Wilkinson and Pickett, 2009), ‘hard times’ and economic crises (Clark, 2014), the reshaping of social class in the 21st century (Savage, 2015) and the rise of the 'precariat' (Standing, 2016). This chapter takes up the challenge of a critical pedagogy for dark times and how such work might be undertaken for and through physical education. Physical education itself as be repositioned in the school curriculum in many countries, most often within larger configurations of school knowledge such as 'health and wellbeing'. This repositioning and the requirement for physical educators to work with new subject matter beyond sports and games has created risk but also opened up new possibilities for critical pedagogy in 'dark times'

School physical education and learning about health : pedagogical strategies for using social media

This chapter considers school physical education, pedagogical strategies and the role of social media in supporting young people's learning about health. I consider what can be learned from the case studies developed from Goodyear, Armour & Wood's (2017) research project, the wider research literature, and some of the implications for pedagogical strategies and teachers' professional learning. I conclude that physical educators can contribute to young people's critical health literacy, develop pedagogies of affect, and deploy social media forms and contents in critical and positive ways. This work will be challenging for physical educators in the face of the pervasive influence of social media in young people's lives

A People's History Of Recent Urban Transportation Innovation

Who are the people leading the charge in urban transportation? As our report explains, the short answer is that it takes leaders from three different sectors of urban society to make change happen quickly.First, there needs to be a robust civic vanguard, the more diverse their range of skills and participation, the better. Second, mayors, commissioners and other city leaders need to create the mandate and champion the change. The third sector is the agency staff. When these three sectors align, relatively quick transformation is possible. Several cities, including New York and Pittsburgh, recently experienced this alignment of a healthy civic community, a visionary and bold mayor and transportation head, and internal agency champions. Our report also highlighted the potential of other cities, such as Charlotte, where the civic sector continues to build on and widen their base

Transforming a 4th year Modern Optics Course Using a Deliberate Practice Framework

We present a study of active learning pedagogies in an upper division physics course. This work was guided by the principle of deliberate practice for the development of expertise, and this principle was used in the design of the materials and the orchestration of the classroom activities of the students. We present our process for efficiently converting a traditional lecture course based on instructor notes into activities for such a course with active learning methods. Ninety percent of the same material was covered and scores on common exam problems showed a 15 % improvement with an effect size greater than 1 after the transformation. We observe that the improvement and the associated effect size is sustained after handing off the materials to a second instructor. Because the improvement on exam questions was independent of specific problem topics and because the material tested was so mathematically advanced and broad (including linear algebra, Fourier Transforms, partial differential equations, vector calculus), we expect the transformation process could be applied to most upper division physics courses having a similar mathematical base.Comment: 31 page