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Animals frequently make adaptive decisions about what to prioritize when faced with multiple, competing demands simultaneously. However, the proximate mechanisms of decision-making in the face of competing demands are not well understood. We explored this question using brain transcriptomics in a classic model system: threespined sticklebacks, where males face conflict between courtship and territorial defence. We characterized the behaviour and brain gene expression profiles of males confronted by a trade-off between courtship and territorial defence by comparing them to males not confronted by this trade-off. When faced with the trade-off, males behaviourally prioritized defence over courtship, and this decision was reflected in their brain gene expression profiles. A distinct set of genes and biological processes was recruited in the brain when males faced a trade-off and these responses were largely non-overlapping across two brain regions. Combined, these results raise new questions about the interplay between the neural and molecular mechanisms involved in decision-making.

 

It has recently been demonstrated experimentally that a turbulent plasma created by the collision of two inhomogeneous, asymmetric, weakly magnetized, laser-produced plasma jets can generate strong stochastic magnetic fields via the small-scale turbulent dynamo mechanism, provided the magnetic Reynolds number of the plasma is sufficiently large. In this paper, we compare such a plasma with one arising from two pre-magnetized plasma jets whose creation is identical save for the addition of a strong external magnetic field imposed by a pulsed magnetic field generator. We investigate the differences between the two turbulent systems using a Thomson-scattering diagnostic, x-ray self-emission imaging, and proton radiography. The Thomson-scattering spectra and x-ray images suggest that the external magnetic field has a limited effect on the plasma dynamics in the experiment. Although the external magnetic field induces collimation of the flows in the colliding plasma jets and although the initial strengths of the magnetic fields arising from the interaction between the colliding jets are significantly larger as a result of the external field, the energies and morphologies of the stochastic magnetic fields post-amplification are indistinguishable. We conclude that, for turbulent laser-plasmas with supercritical magnetic Reynolds numbers, the dynamo-amplified magnetic fields are determined by the turbulent dynamics rather than the seed fields or modest changes in the initial flow dynamics of the plasma, a finding consistent with theoretical expectations and simulations of turbulent dynamos. 

It has recently been demonstrated experimentally that a turbulent plasma created by the collision of two inhomogeneous, asymmetric, weakly magnetized, laser-produced plasma jets can generate strong stochastic magnetic fields via the small-scale turbulent dynamo mechanism, provided the magnetic Reynolds number of the plasma is sufficiently large. In this paper, we compare such a plasma with one arising from two pre-magnetized plasma jets whose creation is identical save for the addition of a strong external magnetic field imposed by a pulsed magnetic field generator. We investigate the differences between the two turbulent systems using a Thomson-scattering diagnostic, x-ray selfemission imaging, and proton radiography. The Thomson-scattering spectra and x-ray images suggest that the external magnetic field has a limited effect on the plasma dynamics in the experiment. Although the external magnetic field induces collimation of the flows in the colliding plasma jets and although the initial strengths of the magnetic fields arising from the interaction between the colliding jets are significantly larger as a result of the external field, the energies and morphologies of the stochastic magnetic fields post-amplification are indistinguishable. We conclude that, for turbulent laser-plasmas with supercritical magnetic Reynolds numbers, the dynamo-amplified magnetic fields are determined by the turbulent dynamics rather than the seed fields or modest changes in the initial flow dynamics of the plasma, a finding consistent with theoretical expectations and simulations of turbulent dynamos. https://doi.org/10.1063/5.0084345 

If an objective of public higher education is to engage with a diversity of communities, then coursework should be less insulated within classrooms. This work describes and analyzes a university course design that supports undergraduate students to experience learning as relational and transformational via Site Visits within various communities. We focus on “technological assemblages” as a way to understand students’ reorientation to the process and purpose of learning (and teaching). We analyze experiences within the course as moments of disorientation, reassembly and stabilization in which students use their mobile devices, bodies and interactions-in-place to understand familiar locations as socially and historically contingent sites of learning (and teaching). We argue that this instructional model does important work of putting students at the nexus of building relationships between the university and other community settings around the city. 

Future tactical communications involves high data rate best effort traffic working alongside real-time traffic for time-critical applications with hard deadlines. Unavailable bandwidth and/or untimely responses may lead to undesired or even catastrophic outcomes. Ethernet-based communication systems are one of the major tactical network standards due to the higher bandwidth, better utilization, and ability to handle heterogeneous traffic. However, Ethernet suffers from inconsistent performance for jitter, latency and bandwidth under heavy loads. The emerging Time-Triggered Ethernet (TTE) solutions promise deterministic Ethernet performance, fault-tolerant topologies and real-time guarantees for critical traffic. In this paper we study the TTE protocol and build a TTTech TTE test bed to evaluate its performance. Through experimental study, the TTE protocol was observed to provide consistent high data rates for best effort messages, determinism with very low jitter for time-triggered messages, and fault-tolerance for minimal packet loss using redundant networking topologies. In addition, challenges were observed that presented a trade-off between the integration cycle and the synchronization overhead. It is concluded that TTE is a capable solution to support heterogeneous traffic in time-critical applications, such as aerospace systems (eg. airplanes, spacecraft, etc.), ground-based vehicles (eg. trains, buses, cars, etc), and cyber-physical systems (eg. smart-grids, IoT, etc.). 

This symposium aims to explore current research working toward conceptualizing and measuring productive disciplinary engagement (PDE) contextualized in diverse learning and project contexts. Disciplinary engagement is critical for fostering students’ deep, integrated understanding of STEM content and disciplinary practices. However, there are significant challenges to reaching this engagement quality, with CSCL environments providing opportunities and supports for engagement, but also posing challenges. This symposium aims to account for recent developments, as presenters showcase rich range in exploring application of PDE in diverse domains, grade bands, and learning contexts. The presentations also showcase a range of methods to analyze PDE as collective, situated, cross-contextual, dynamic, and generative.