Taut ideal triangulations of 3-manifolds

A taut ideal triangulation of a 3-manifold is a topological ideal triangulation with extra combinatorial structure: a choice of transverse orientation on each ideal 2-simplex, satisfying two simple conditions. The aim of this paper is to demonstrate that taut ideal triangulations are very common, and that their behaviour is very similar to that of a taut foliation. For example, by studying normal surfaces in taut ideal triangulations, we give a new proof of Gabai's result that the singular genus of a knot in the 3-sphere is equal to its genus.Comment: Published in Geometry and Topology at http://www.maths.warwick.ac.uk/gt/GTVol4/paper12.abs.htm

Ultrashort Q-switched pulses from a passively mode-locked distributed Bragg reflector semiconductor laser

A compact semiconductor mode-locked laser (MLL) is presented that demonstrates strong passive Q-switched mode-locking over a wide range of drive conditions. The Q-switched frequency is tunable between 1 and 4 GHz for mode-locked pulses widths around 3.5 ps. The maximum ratio of peak to average power of the pulse-train is >120, greatly exceeding that of similarly sized passively MLLs

Impact of climate change and bioenergy on nutrition

Food security has deteriorated since 1995 and reductions in child malnutrition are proceeding too slowly to meet the Millennium Development Goal (MDG) target for halving hunger by 2015. Three major challenges threaten to drastically complicate efforts to overcome food insecurity and malnutrition: climate change, the growing use of food crops as a source of fuel and soaring food prices. Food security has four dimensions: food availability, access to food, stability of supply and access and safe and healthy food utilization. It is a key factor in good nutrition, along with health, sanitation and care practices. Globally, one billion people are currently without access to safe water and over 2 billion lack adequate sanitation facilities. Present global food supplies are more than adequate to provide everyone with all the needed calories, if the food were equally distributed. But over 820 million people in developing countries have calorie-deficient diets; over 60 percent live in Sub-Saharan Africa and South Asia.Climate change, Bioenergy, Nutrition, food security, Food prices, Sustainable development,

Editor\u27s Introduction: Playing for Keeps: Games and Cultural Resistance [Special Issue]

This edition is as much about Game Studies as it about the games being studied. At its heart there are really two impulses behind the collection of critical thought we have been fortunate enough to gather for this issue of Reconstruction. First, there is the sense that games can’t do anything. Second, there is the sense that games don’t do anything. Their origin (and the underlying biases) makes these sentiments particularly intriguing. In the simplest terms, these premises delineate competing camps, as well. Roger Ebert notoriously asserts that video games will never be art (Ebert). Similarly, and yet quite differently, Espen Aarseth proclaims that a game has no intertext (cf. 48). Frankly, locating a project within these dismally disparate parameters is kind out like hitting water after falling out of a boat in the Pacific Ocean. It is, for all intents and purposes, irrelevant. Nevertheless, the question of games and cultural resistance is something of a loaded one given the prevailing popular and professorial positions on the subject. For his part, Gonzalo Frasca, wonders if (video) games will ever have the purchase to qualify as progressive political texts (cf. 86). Moreover, neither of the current editors began approaching games, gamers and gaming with either or even an inkling for these positions. Quite simply, we recognize that gaming is a (kind of) social act. It doesn’t take a rhetorician—though one of us is—to notice that any assertion implies its negation, nor does it take someone versed in cultural theory—though that would be the other of us—to find that any discourse defines itself by implicitly disqualifying and that this signals a clear relationship of power

A Detailed Study of Giants and Horizontal Branch Stars in M68: Atmospheric Parameters and Chemical Abundances

In this paper, we present a detailed high-resolution spectroscopic study of post main sequence stars in the Globular Cluster M68. Our sample, which covers a range of 4000 K in $T_{eff}$, and 3.5 dex in $log(g)$, is comprised of members from the red giant, red horizontal, and blue horizontal branch, making this the first high-resolution globular cluster study covering such a large evolutionary and parameter space. Initially, atmospheric parameters were determined using photometric as well as spectroscopic methods, both of which resulted in unphysical and unexpected $T_{eff}$, $log(g)$, $\xi_{t}$, and [Fe/H] combinations. We therefore developed a hybrid approach that addresses most of these problems, and yields atmospheric parameters that agree well with other measurements in the literature. Furthermore, our derived stellar metallicities are consistent across all evolutionary stages, with $\langle$[Fe/H]$\rangle$ = $-$2.42 ($\sigma$ = 0.14) from 25 stars. Chemical abundances obtained using our methodology also agree with previous studies and bear all the hallmarks of globular clusters, such as a Na-O anti-correlation, constant Ca abundances, and mild $r$-process enrichment.Comment: Accepted to the Astronomical Journa

Weak government, strong parliament? A preview of Theresa May’s legislative challenges

Being the first without a majority in the Commons or the Lords for 40 years, how will May’s minority government implement any part of their legislative agenda? How will committees function? Will the smaller parties in the Commons work together? Marc Geddes, Alexandra Meakin, and Louise Thompson offer a preview of how the 2017 Parliament may function

Introduction: A Game\u27s Study Manifesto

In the epigraph to this collection, we return to a foundational text of the western literary canon, Homer’s Odyssey, and see in Penelope’s “bow contest” an illustrative moment in the history of game culture. Having fought in the Trojan War and having survived his ten-year trek home, the weary Odysseus cannot simply show up—the returning hero must rout the odious suitors whom Penelope has forestalled. In order to buy more time for vengeance, Odysseus disguises himself as an old beggar; in order to buy more time for deferral, Penelope creates an unwinnable game: she will marry the suitor able to string Odysseus’ bow and shoot an arrow through the handles of twelve axes. We contend that this ludic scene from the Odyssey—an exemplar of literature, which is a constituent of Western culture—mirrors the ludic scene of digital games—exemplars of media, which are constituent of global culture.1 As a canonical text, the Odyssey clearly has an influence on subsequent texts, yet we know that contemporary texts will condition reception of the Odyssey just as surely as we saw and heard people on the Costa Concordia claim that their experience was like being in the movie Titanic instead of like being aboard the ship RMS Titanic