Evidence indicates that Antarctic minke whales (AMWs) in the Ross Sea affect the foraging behaviour, especially diet, of sympatric Adélie penguins (ADPEs) by, we hypothesize, influencing the availability of prey they have in common, mainly crystal krill. To further investigate this interaction, we undertook a study in McMurdo Sound during 2012–2013 and 2014–2015 using telemetry and biologging of whales and penguins, shore-based observations and quantification of the preyscape. The 3D distribution and density of prey were assessed using a remotely operated vehicle deployed along and to the interior of the fast-ice edge where AMWs and ADPEs focused their foraging. Acoustic surveys of prey and foraging behaviour of predators indicate that prey remained abundant under the fast ice, becoming successively available to air-breathing predators only as the fast ice retreated. Over both seasons, the ADPE diet included less krill and more Antarctic silverfish once AMWs became abundant, but the penguins' foraging behaviour (i.e. time spent foraging, dive depth, distance from colony) did not change. In addition, over time, krill abundance decreased in the upper water column near the ice edge, consistent with the hypothesis (and previously gathered information) that AMW and ADPE foraging contributed to an alteration of prey availability.

La prise en charge non-pharmacologique de la maladie d’Alzheimer et des maladies apparentées (MA) représente un enjeu de santé majeur chez les personnes âgées . L’environnement Enrichi (EE), combinaison de stimulations cognitive, physique et d’engagement social en contexte émotionnel positif, apparaît comme une méthode efficace pour lutter contre la progression d’une MA . La principale difficulté est de proposer aux patients un EE adapté et motivant. Les serious games peuvent aider dans ce sens . Xtorp est un Serious exerGame (à activité physique, SeG) d’action/aventure développé pour KinectTM. Le joueur pilote un sous-marin (Fig. 1). Il doit devenir Amiral 5 étoiles en collectant de l’expérience au cours de batailles et missions. Dix patients (MA stade léger) et 8 témoins ont suivi un programme d’entrainement avec le jeu durant 1 mois, réparties en 12 séances. Les performances au jeu, les émotions perçues (PANAS) et l’intensité d’effort physique induite par le jeu ont été étudiées. Tous les participants ont terminé au moins une fois Xtorp. Les patients ont une capacité de jeu inférieure aux témoins (temps total de jeu et vitesse de progression patents : 420 minutes et 185 points d’expérience/minute, témoins : 489 minutes et 287 points d’expérience/minute). Les patients et les témoins n’ont quasiment ressenti que des émotions positives, légèrement plus fortes pour les témoins (PANAS positifs patients : 27/50, témoins, 36/50 ; PANAS négatifs patients : 12/50, témoins 11/50). Enfin, le jeu a été stimulant physiquement mais à un moindre degré chez les patients (fréquence cardiaque de réserve moyenne et pic par séance patients : 33 % et 53 %, témoins : 44 % et 62 %). En conclusion Xtorp est un EE utilisable, motivant qui permet de réaliser une activité physique potentiellement modérée chez des patients présentant des troubles cognitifs.

The detection of fireballs streaks in astronomical imagery can be carried out by a variety of methods. The Desert Fireball Network uses a network of cameras to track and triangulate incoming fireballs to recover meteorites with orbits and to build a fireball orbital dataset. Fireball detection is done on-board camera, but due to the design constraints imposed by remote deployment, the cameras are limited in processing power and time. We describe the processing software used for fireball detection under these constrained circumstances. Two different approaches were compared: (1) A single-layer neural network with 10 hidden units that were trained using manually selected fireballs and (2) a more traditional computational approach based on cascading steps of increasing complexity, whereby computationally simple filters are used to discard uninteresting portions of the images, allowing for more computationally expensive analysis of the remainder. Both approaches allowed a full night’s worth of data (over a thousand 36-megapixel images) to be processed each day using a low-power single-board computer. We distinguish between large (likely meteorite-dropping) fireballs and smaller fainter ones (typical ‘shooting stars’). Traditional processing and neural network algorithms both performed well on large fireballs within an approximately 30 000-image dataset, with a true positive detection rate of 96% and 100%, respectively, but the neural network was significantly more successful at smaller fireballs, with rates of 67% and 82%, respectively. However, this improved success came at a cost of significantly more false positives for the neural network results, and additionally the neural network does not produce precise fireball coordinates within an image (as it classifies). Simple consideration of the network geometry indicates that overall detection rate for triangulated large fireballs is calculated to be better than 99.7% and 99.9%, by ensuring that there are multiple double-station opportunities to detect any one fireball. As such, both algorithms are considered sufficient for meteor-dropping fireball event detection, with some consideration of the acceptable number of false positives compared to sensitivity.

Despite the well-documented health benefits of physical activity in older adults, participation levels remain low. With rapid global population ageing, intensive efforts are needed to encourage higher levels of participation to ameliorate the negative effects of physical inactivity for older individuals and society as a whole. The aim of this qualitative study was to inform future physical activity promotion interventions by examining factors contributing to low activity levels among older people undertaking less than half the recommended level of moderate-to-vigorous physical activity (MVPA). Semi-structured interviews were conducted with 102 (65% female) community-dwelling Western Australians aged 60+ years (mean = 71.52, standard deviation = 6.26) who engaged in ⩽75 minutes of MVPA per week as measured by accelerometers. Several modifiable and unmodifiable barriers were identified, of which poor health featured most prominently. Lifetime physical inactivity, caring duties, low motivation, misperceptions of physical activity and ageing, and a lack of affordable and attractive options were the other barriers identified. The results suggest that strategies are needed to raise awareness of current physical activity guidelines, normalise engagement in MVPA throughout the lifespan, develop initiatives to motivate participation, improve the availability of affordable physical activity programmes that are attractive to this population segment, and facilitate participation among those with intensive caring responsibilities.

Unlike most bird species, individual kingfisher species (Aves: Alcedinidae) are typically parasitized by only a single genus of louse (Alcedoffula, Alcedoecus, or Emersoniella). These louse genera are typically specific to a particular kingfisher subfamily. Specifically, Alcedoecus and Emersoniella parasitize Halcyoninae, whereas Alcedoffula parasitizes Alcedininae and Cerylinae. Although Emersoniella is geographically restricted to the Indo-Pacific region, Alcedoecus and Alcedoffula are geographically widespread. We used DNA sequences from two genes, the mitochondrial COI and nuclear EF-1α genes, to infer phylogenies for the two geographically widespread genera of kingfisher lice, Alcedoffula and Alcedoecus. These phylogenies included 47 kingfisher lice sampled from 11 of the 19 currently recognized genera of kingfishers. We compared louse phylogenies to host phylogenies to reconstruct their cophylogenetic history. Two distinct clades occur within Alcedoffula, one that infests Alcedininae and a second that infests Cerylinae. All species of Alcedoecus were found only on host species of the subfamily Halcyoninae. Cophylogenetic analysis indicated that Alcedoecus, as well as the clade of Alcedoffula occurring on Alcedininae, do not show evidence of cospeciation. In contrast, the clade of Alcedoffula occurring on Cerylinae showed strong evidence of cospeciation.

A sound gradual type system ensures that untyped components of a program can never break the guarantees of statically typed components. This assurance relies on runtime checks, which in turn impose performance overhead in proportion to the frequency and nature of interaction between typed and untyped components. The literature on gradual typing lacks rigorous descriptions of methods for measuring the performance of gradual type systems. This gap has consequences for the implementors of gradual type systems and developers who use such systems. Without systematic evaluation of mixed-typed programs, implementors cannot precisely determine how improvements to a gradual type system affect performance. Developers cannot predict whether adding types to part of a program will significantly degrade (or improve) its performance. This paper presents the first method for evaluating the performance of sound gradual type systems. The method quantifies both the absolute performance of a gradual type system and the relative performance of two implementations of the same gradual type system. To validate the method, the paper reports on its application to 20 programs and 3 implementations of Typed Racket.

Boyer & Petersen (B&P) argue that folk-economic beliefs are widespread – shaped by evolved cognitive systems – and they offer exemplar beliefs to illustrate their thesis. In this commentary, we highlight evidence of substantial variation in one of these exemplars: beliefs about immigration. Contra claims by B&P, we argue that the balance of this evidence suggests the “folk” may actually hold positive beliefs about the economic impact of immigration.