On the Impact of Fair Best Response Dynamics

In this work we completely characterize how the frequency with which each player participates in the game dynamics affects the possibility of reaching efficient states, i.e., states with an approximation ratio within a constant factor from the price of anarchy, within a polynomially bounded number of best responses. We focus on the well known class of congestion games and we show that, if each player is allowed to play at least once and at most $\beta$ times any $T$ best responses, states with approximation ratio $O(\beta)$ times the price of anarchy are reached after $T \lceil \log \log n \rceil$ best responses, and that such a bound is essentially tight also after exponentially many ones. One important consequence of our result is that the fairness among players is a necessary and sufficient condition for guaranteeing a fast convergence to efficient states. This answers the important question of the maximum order of $\beta$ needed to fast obtain efficient states, left open by [9,10] and [3], in which fast convergence for constant $\beta$ and very slow convergence for $\beta=O(n)$ have been shown, respectively. Finally, we show that the structure of the game implicitly affects its performances. In particular, we show that in the symmetric setting, in which all players share the same set of strategies, the game always converges to an efficient state after a polynomial number of best responses, regardless of the frequency each player moves with

PolNet Analysis: a software tool for the quantification of network-level endothelial cell polarity and blood flow during vascular remodelling

In this paper, we present PolNet, an open source software tool for the study of blood flow and cell-level biological activity during vessel morphogenesis. We provide an image acquisition, segmentation, and analysis protocol to quantify endothelial cell polarity in entire in vivo vascular networks. In combination, we use computational fluid dynamics to characterise the haemodynamics of the vascular networks under study. The tool enables, for the first time, network-level analysis of polarity and flow for individual endothelial cells. To date, PolNet has proven invaluable for the study of endothelial cell polarisation and migration during vascular patterning, as demonstrated by our recent papers (Franco 2015, Franco 2016a). Additionally, the tool can be easily extended to correlate blood flow with other experimental observations at the cellular/molecular level. We release the source code of our tool under the LGPL licence

Toxicological screening and DNA sequencing detects contamination and adulteration in regulated herbal medicines and supplements for diet, weight loss and cardiovascular health

Use of herbal medicines and supplements by consumers to prevent or treat disease, particularly chronic conditions continues to grow, leading to increased awareness of the minimal regulation standards in many countries. Fraudulent, adulterated and contaminated herbal and traditional medicines and dietary supplements are a risk to consumer health, with adverse effects and events including overdose, drug-herb interactions and hospitalisation. The scope of the risk has been difficult to determine, prompting calls for new approaches, such as the combination of DNA metabarcoding and mass spectrometry used in this study. Here we show that nearly 50% of products tested had contamination issues, in terms of DNA, chemical composition or both. Two samples were clear cases of pharmaceutical adulteration, including a combination of paracetamol and chlorpheniramine in one product and trace amounts of buclizine, a drug no longer in use in Australia, in another. Other issues include the undeclared presence of stimulants such as caffeine, synephrine or ephedrine. DNA data highlighted potential allergy concerns (nuts, wheat), presence of potential toxins (Neem oil) and animal ingredients (reindeer, frog, shrew), and possible substitution of bird cartilage in place of shark. Only 21% of the tested products were able to have at least one ingredient corroborated by DNA sequencing. This study demonstrates that, despite current monitoring approaches, contaminated and adulterated products are still reaching the consumer. We suggest that a better solution is stronger pre-market evaluation, using techniques such as that outlined in this study

Toxicological screening and DNA sequencing detects contamination and adulteration in regulated herbal medicines and supplements for diet, weight loss and cardiovascular health

Use of herbal medicines and supplements by consumers to prevent or treat disease, particularly chronic conditions continues to grow, leading to increased awareness of the minimal regulation standards in many countries. Fraudulent, adulterated and contaminated herbal and traditional medicines and dietary supplements are a risk to consumer health, with adverse effects and events including overdose, drug-herb interactions and hospitalisation. The scope of the risk has been difficult to determine, prompting calls for new approaches, such as the combination of DNA metabarcoding and mass spectrometry used in this study. Here we show that nearly 50% of products tested had contamination issues, in terms of DNA, chemical composition or both. Two samples were clear cases of pharmaceutical adulteration, including a combination of paracetamol and chlorpheniramine in one product and trace amounts of buclizine, a drug no longer in use in Australia, in another. Other issues include the undeclared presence of stimulants such as caffeine, synephrine or ephedrine. DNA data highlighted potential allergy concerns (nuts, wheat), presence of potential toxins (Neem oil) and animal ingredients (reindeer, frog, shrew), and possible substitution of bird cartilage in place of shark. Only 21% of the tested products were able to have at least one ingredient corroborated by DNA sequencing. This study demonstrates that, despite current monitoring approaches, contaminated and adulterated products are still reaching the consumer. We suggest that a better solution is stronger pre-market evaluation, using techniques such as that outlined in this study

Malicious Bayesian Congestion Games

In this paper, we introduce malicious Bayesian congestion games as an extension to congestion games where players might act in a malicious way. In such a game each player has two types. Either the player is a rational player seeking to minimize her own delay, or - with a certain probability - the player is malicious in which case her only goal is to disturb the other players as much as possible. We show that such games do in general not possess a Bayesian Nash equilibrium in pure strategies (i.e. a pure Bayesian Nash equilibrium). Moreover, given a game, we show that it is NP-complete to decide whether it admits a pure Bayesian Nash equilibrium. This result even holds when resource latency functions are linear, each player is malicious with the same probability, and all strategy sets consist of singleton sets. For a slightly more restricted class of malicious Bayesian congestion games, we provide easy checkable properties that are necessary and sufficient for the existence of a pure Bayesian Nash equilibrium. In the second part of the paper we study the impact of the malicious types on the overall performance of the system (i.e. the social cost). To measure this impact, we use the Price of Malice. We provide (tight) bounds on the Price of Malice for an interesting class of malicious Bayesian congestion games. Moreover, we show that for certain congestion games the advent of malicious types can also be beneficial to the system in the sense that the social cost of the worst case equilibrium decreases. We provide a tight bound on the maximum factor by which this happens.Comment: 18 pages, submitted to WAOA'0

Finding footy : female fan socialization and Australian rules football

The question of how, irrespective of gender, a person becomes a sports fan has been absent in sociological studies of sports supporters. Distinct from other studies of sport spectatorship that focus on the practices of already existing (and overwhelmingly male) fans, our research is the first to consider how women become supporters, and in doing so, it begins to redress the significant under-representation of women in sports fan research. From interviews with female supporters of the Australian Football League (AFL), this article identifies and critically assesses the modes by which women come to support sport. We propose four categories to explain the different ways women accomplish fandom, focusing on the importance of strong social ties and doxic actions in this process. The events, experiences and social relations that inform women\u27s first encounters with AFL offers a template for the wider consideration of women as social agents in the sporting landscape

Periodic and Quasiperiodic Motion of an Elongated Microswimmer in Poiseuille Flow

We study the dynamics of a prolate spheroidal microswimmer in Poiseuille flow for different flow geometries. When moving between two parallel plates or in a cylindrical microchannel, the swimmer performs either periodic swinging or periodic tumbling motion. Although the trajectories of spherical and elongated swimmers are qualitatively similar, the swinging and tumbling frequency strongly depends on the aspect ratio of the swimmer. In channels with reduced symmetry the swimmers perform quasiperiodic motion which we demonstrate explicitely for swimming in a channel with elliptical cross section

Spontaneous Chiral-Symmetry Breaking in Three-Dimensional QED with a Chern--Simons Term

In three-dimensional QED with a Chern--Simons term we study the phase structure associated with chiral-symmetry breaking in the framework of the Schwinger--Dyson equation. We give detailed analyses on the analytical and numerical solutions for the Schwinger--Dyson equation of the fermion propagator, where the nonlocal gauge-fixing procedure is adopted to avoid wave-function renormalization for the fermion. In the absence of the Chern--Simons term, there exists a finite critical number of four-component fermion flavors, at which a continuous (infinite-order) chiral phase transition takes place and below which the chiral symmetry is spontaneously broken. In the presence of the Chern--Simons term, we find that the spontaneous chiral-symmetry-breaking transition continues to exist, but the type of phase transition turns into a discontinuous first-order transition. A simple stability argument is given based on the effective potential, whose stationary point gives the solution of the Schwinger-Dyson equation.Comment: 34 pages, revtex, with 9 postscriptfigures appended (uuencoded

Nash Equilibria in Discrete Routing Games with Convex Latency Functions

In a discrete routing game, each of n selfish users employs a mixed strategy to ship her (unsplittable) traffic over m parallel links. The (expected) latency on a link is determined by an arbitrary non-decreasing, non-constant and convex latency function φ. In a Nash equilibrium, each user alone is minimizing her (Expected) Individual Cost, which is the (expected) latency on the link she chooses. To evaluate Nash equilibria, we formulate Social Cost as the sum of the users ’ (Expected) Individual Costs. The Price of Anarchy is the worst-case ratio of Social Cost for a Nash equilibrium over the least possible Social Cost. A Nash equilibrium is pure if each user deterministically chooses a single link; a Nash equilibrium is fully mixed if each user chooses each link with non-zero probability. We obtain: For the case of identical users, the Social Cost of any Nash equilibrium is no more than the Social Cost of the fully mixed Nash equilibrium, which may exist only uniquely. Moreover, instances admitting a fully mixed Nash equilibrium enjoy an efficient characterization. For the case of identical users, we derive two upper bounds on the Price of Anarchy: For the case of identical links with a monomial latency function φ(x) = x d, the Price of Anarchy is the Bell number of order d + 1. For pure Nash equilibria, a generic upper bound from the Wardrop model can be transfered to discrete routing games. For polynomial latency functions with non-negative coefficients and degree d, this yields an upper bound of d + 1. For th