River research and applications across borders

Rivers flow across national borders, unfettered by political distinctions, and the ecological health of rivers is closely linked to their degree of connectivity. River research today is more global than it has ever been, but we show that river research, engineering, and management still operate within homegrown local paradigms. As a basis for this discussion, we studied the citation networks surrounding the most widely cited papers in our field, assessing the degree to which researchers have collaborated across geographical boundaries and fully drawn from the international literature. Despite gains over time, our field remains surprisingly and pervasively provincial. The likely explanation for provincial bias is that researchers are generally more familiar and comfortable with their own research methods, sites, and agendas. However, local focus has tangible consequences. For example, contrasting paradigms and differing approaches to river restoration and to flood-risk management show that opportunities are lost when we fail to learn from the successes and failures of other regions. As Sharp and Leshner (2014; p. 579) have argued, "the search for solutions needs to draw upon the talents and innovative ideas of scientists, engineers, and societal leaders worldwide to overcome traditional and nationalistic paradigms that have so far been inadequate to meeting these challenges.

Local Acceleration of Neurofilament Transport at Nodes of Ranvier

© 2019 the authors. Myelinated axons are constricted at nodes of Ranvier. These constrictions are important physiologically because they increase the speed of saltatory nerve conduction, but they also represent potential bottlenecks for the movement of axonally transported cargoes. One type of cargo are neurofilaments, which are abundant space-filling cytoskeletal polymers that function to increase axon caliber. Neurofilaments move bidirectionally along axons, alternating between rapid movements and prolonged pauses. Strikingly, axon constriction at nodes is accompanied by a reduction in neurofilament number that can be as much as 10-fold in the largest axons. To investigate how neurofilaments navigate these constrictions, we developed a transgenic mouse strain that expresses a photoactivatable fluorescent neurofilament protein in neurons. We used the pulse-escape fluorescence photoactivation technique to analyze neurofilament transport in mature myelinated axons of tibial nerves from male and female mice of this strain ex vivo. Fluorescent neurofilaments departed the activated region more rapidly in nodes than in flanking internodes, indicating that neurofilament transport is faster in nodes. By computational modeling, we showed that this nodal acceleration can be explained largely by a local increase in the duty cycle of neurofilament transport (i.e., the proportion of the time that the neurofilaments spend moving). We propose that this transient acceleration functions to maintain a constant neurofilament flux across nodal constrictions, much as the current increases where a river narrows its banks. In this way, neurofilaments are prevented from piling up in the flanking internodes, ensuring a stable neurofilament distribution and uniform axonal morphology across these physiologically important axonal domains

Distributed Cognition in Aid of Interdisciplinary Collaborations

What does it take to perform collaborative interdisciplinarity with good epistemic and academic results? This pragmatical question, slightly rephrased, has been one of the few key issues of the philosophical studies on interdisciplinarity since the Seventies. In this paper I aim at addressing that question adopting a conceptual framework weirdly not yet used for this purpose: distributed cognition theories. In particular I will focus on the embodied, emerging, and extended nature of cognitive activities at the core of successful examples of collaborative interdisciplinarity. In the first section of this paper I will briefly review the literature on interdisciplinary collaborations. In the second section I will present the perspective from which I aim at addressing their recurrent problems: a broadly conceived distributed cognition theory, which incorporates insights from the extended mind approach, and from the theories on emerging and embodied cognition. In the third section of the paper I will analyze some of the usual emerging problems of collaborative interdisciplinarity by referring to some well-documented case studies. Then, I will propose some ways to face those problems in the organization and development of a collaborative interdisciplinary project, referring to it as a complex system of distributed cognitive activities