A Problem of Play for Democratic Education? Abstraction, Realism, and Exploration in Learning Games. A Response to The Challenges of Gaming for Democratic Education: The Case of iCivics

In this review article, I argue that games are complementary, not self-supporting, learning tools for democratic education because they can: (a) offer simplified, but often not simple, outlines (later called “models”) of complex social systems that generate further inquiry; (b) provide practice spaces for exploring systems that do not have the often serious consequences of taking direct and immediate social, civic, and legal action; and (c) use rules to allow players to explore this aforementioned outline or model by making decisions and seeing an outcome. To make these arguments, I perform a close reading of three examples of participatory and playful media that could be germane to, but are not designed for, educational settings: the early-20th-century board game The Landlord’s Game, YouTube videos advising about law enforcement encounters, and the dystopian indie game Papers, Please

Forbidden Fruit: Dryden\u27s The State of Innocence And Fall of Man, An Operatic Version of Paradise Lost

Ever since Dryden published his opera The state of innocence, critics have speculated about his reasons for making a stage adaptation of Milton\u27s Paradise lost. The fact that Dryden worked for Milton in Cromwell\u27s government may have been a factor. Dryden\u27s Puritan indoctrination during childhood, followed by influences from a royalist schoolmaster in his teenage years, makes the answer to the question somewhat more complex, as does the fact that the play, its source a Puritan epic adapted by an Anglican royalist poet, is dedicated to the Catholic bride of James, Duke of York and brother to Charles II. Throughout the two works, theological, sociological, and political differences abound, but it is Dryden\u27s stage characters that are the primary vehicles through which he portrays his divergence from Milton\u27s epic. Lucifer, the ultimate evil, is in rebellion against Christ the King, and, while Adam ponders the dilemma of free will versus preordination, the ever-narcissistic Eve traipses through the garden toward her meeting with the serpent. This meeting, being both preordained and a result of Eve\u27s (and Lucifer\u27s) free will, brings about the fall of Man. Thus, Dryden and Milton take the Old Testament story and transform it into a vehicle for their own political, social, and theological agendas

“Hagene, der vil ungetriuwe man”? Courtly Rivalry, Loyalty Conflict, and the Figure of Hagen in the Nibelungenlied

The variety of scholarly approaches to the Middle High German poem Das Nibelungenlied has generated a wide range of conflicting analyses of the character of Hagen, a figure who plays a key role in both the plot and the interpretation of the work. This thesis proposes that viewing Hagen’s relationship with Siegfried in relation to the poem’s central theme of loyalty (triuwe) allows for an analysis that integrates both the positive and negative aspects of Hagen’s character. By examining the depiction of courtly rivalry in four contemporary Middle High German works (Herzog Ernst B, Wolfdietrich A, Tristan, and Parzival), I outline the basic features of this common medieval narrative structure and then apply the same framework to a close reading of the relationship between Hagen and Siegfried in the Nibelungenlied. I also argue that the incorporation of the courtly rivalry motif as a unifying theme of the text allows the poet to take a stance on the broader issue of loyalty conflict, a topic which appears frequently in contemporary literature and had particular relevance within the political climate of medieval Germany. My reading of the character of Hagen can thus hopefully shed new light on the thematic structure of the Nibelungenlied as well as on the relationship between the poem and the literary and historical context in which it was written

The evolution and comparative neurobiology of endocannabinoid signalling

CB(1)- and CB(2)-type cannabinoid receptors mediate effects of the endocannabinoids 2-arachidonoylglycerol (2-AG) and anandamide in mammals. In canonical endocannabinoid-mediated synaptic plasticity, 2-AG is generated postsynaptically by diacylglycerol lipase alpha and acts via presynaptic CB(1)-type cannabinoid receptors to inhibit neurotransmitter release. Electrophysiological studies on lampreys indicate that this retrograde signalling mechanism occurs throughout the vertebrates, whereas system-level studies point to conserved roles for endocannabinoid signalling in neural mechanisms of learning and control of locomotor activity and feeding. CB(1)/CB(2)-type receptors originated in a common ancestor of extant chordates, and in the sea squirt Ciona intestinalis a CB(1)/CB(2)-type receptor is targeted to axons, indicative of an ancient role for cannabinoid receptors as axonal regulators of neuronal signalling. Although CB(1)/CB(2)-type receptors are unique to chordates, enzymes involved in biosynthesis/inactivation of endocannabinoids occur throughout the animal kingdom. Accordingly, non-CB(1)/CB(2)-mediated mechanisms of endocannabinoid signalling have been postulated. For example, there is evidence that 2-AG mediates retrograde signalling at synapses in the nervous system of the leech Hirudo medicinalis by activating presynaptic transient receptor potential vanilloid-type ion channels. Thus, postsynaptic synthesis of 2-AG or anandamide may be a phylogenetically widespread phenomenon, and a variety of proteins may have evolved as presynaptic (or postsynaptic) receptors for endocannabinoids

Delay-independent asymptotic stability in monotone systems

Monotone systems comprise an important class of dynamical systems that are of interest both for their wide applicability and because of their interesting mathematical properties. It is known that under the property of quasimono-tonicity time-delayed systems become monotone, and some remarkable properties have been reported for such systems. These include, for example, the fact that for linear systems global asymptotic stability of the undelayed system implies global asymptotic stability for the delayed system under arbitrary bounded delays. Nevertheless, extensions to nonlinear systems have thus far relied on various restrictive conditions, such as homogeneity and subhomogeneity, and it has been conjectured that these can be relaxed. Our aim in this paper is to show that this is feasible for a general class of nonlinear monotone systems, by deriving asymptotic stability results in which simple properties of the undelayed system lead to delay-independent stability. In particular, one of our results is to show that if the undelayed system has a convergent trajectory that is unbounded in all components as t → -∞ then the system is globally asymptotically stable for arbitrary time-varying delays. This follows from a more general result derived in the paper where delay-independent regions of attraction are quantified from the asymptotic behavior of individual trajectories of the undelayed system. This result recovers various known delay-independent stability results, and several examples are included in the paper to illustrate the significance of the proposed stability conditions.This is the author accepted manuscript. The final version is available from IEEE via http://dx.doi.org/10.1109/ACC.2015.717206

Delay-independent incremental stability in time-varying monotone systems satisfying a generalized condition of two-sided scalability

Monotone systems generated by delay differential equations with explicit time-variation are of importance in the modeling of a number of significant practical problems, including the analysis of communications systems, population dynamics, and consensus protocols. In such problems, it is often of importance to be able to guarantee delay-independent incremental asymptotic stability, whereby all solutions converge toward each other asymptotically, thus allowing the asymptotic properties of all trajectories of the system to be determined by simply studying those of some particular convenient solution. It is known that the classical notion of quasimonotonicity renders time-delayed systems monotone. However, this is not sufficient alone to obtain such guarantees. In this work we show that by combining quasimonotonicity with a condition of scalability motivated by wireless networks, it is possible to guarantee incremental asymptotic stability for a general class of systems that includes a variety of interesting examples. Furthermore, we obtain as a corollary a result of guaranteed convergence of all solutions to a quantifiable invariant set, enabling time-invariant asymptotic bounds to be obtained for the trajectories even if the precise values of time-varying parameters are unknown.Engineering and Physical Sciences Research Counci

Stability of a general class of distributed algorithms for power control in time-varying wireless networks

In order for a wireless network to function effectively, the signal power of each user's transmitter must be sufficiently large to ensure a reliable uplink connection to the receiver, but not so large as to cause interference with neighboring users. We consider a general class of distributed algorithms for the control of transmitter power allocations in wireless networks with a general form of interference nonlinearity. In particular, we allow this interference to have explicit time-dependence, allowing our analysis to remain valid for network configurations that vary with time. We employ appropriately constructed Lyapunov functions to show that any bounded power distribution obtained from these algorithms is uniformly asymptotically stable. Further, we use Lyapunov-Razumikhin functions to show that, even when the system incorporates heterogeneous, time-varying delays, any solution along which the generalized system nonlinearity is bounded must also be uniformly asymptotically stable. Moreover, in both of these cases this stability is shown to be global, meaning that every power distribution has the same asymptotic behavior. These results are also used in the paper to derive time-invariant asymptotic bounds for the trajectories when the system nonlinearities are appropriately bounded