A Bulk-Parallel Priority Queue in External Memory with STXXL

We propose the design and an implementation of a bulk-parallel external memory priority queue to take advantage of both shared-memory parallelism and high external memory transfer speeds to parallel disks. To achieve higher performance by decoupling item insertions and extractions, we offer two parallelization interfaces: one using "bulk" sequences, the other by defining "limit" items. In the design, we discuss how to parallelize insertions using multiple heaps, and how to calculate a dynamic prediction sequence to prefetch blocks and apply parallel multiway merge for extraction. Our experimental results show that in the selected benchmarks the priority queue reaches 75% of the full parallel I/O bandwidth of rotational disks and and 65% of SSDs, or the speed of sorting in external memory when bounded by computation.Comment: extended version of SEA'15 conference pape

Ultraluminous Infrared Galaxies

At luminosities above ~10^{11} L_sun, infrared galaxies become the dominant population of extragalactic objects in the local Universe (z < 0.5), being more numerous than optically selected starburst and Seyfert galaxies, and QSOs at comparable bolometric luminosity. At the highest luminosities, ultraluminous infrared galaxies (ULIGs: L_ir > 10^{12} L_sun), outnumber optically selected QSOs by a factor of ~1.5-2. All of the nearest ULIGs (z < 0.1) appear to be advanced mergers that are powered by both a circumnuclear starburst and AGN, both of which are fueled by an enormous concentration of molecular gas (~10^{10} M_sun) that has been funneled into the merger nucleus. ULIGs may represent a primary stage in the formation of massive black holes and elliptical galaxy cores. The intense circumnuclear starburst that accompanies the ULIG phase may also represent a primary stage in the formation of globular clusters, and the metal enrichment of the intergalactic medium by gas and dust expelled from the nucleus due to the combined forces of supernova explosions and powerful stellar winds.Comment: LaTex, 6 pages with 4 embedded .eps figures. Postscript version plus color plates available at http://www.ifa.hawaii.edu/users/sanders/astroph/s186/plates.html To appear in "Galaxy Interactions at Low and High Redshift" IAU Symposium 186, Kyoto, Japan, eds. J.E. Barnes and D.B. Sander

Modified Newtonian Dynamics as an Alternative to Dark Matter

Modified Newtonian dynamics (MOND) is an empirically motivated modification of Newtonian gravity or inertia suggested by Milgrom as an alternative to cosmic dark matter. The basic idea is that at accelerations below a0 ~ 10^{-8} cm/s^2 ~ cH0/6 the effective gravitational attraction approaches sqrt{gN*a0} where gN is the usual Newtonian acceleration. This simple algorithm yields flat rotation curves for spiral galaxies and a mass-rotation velocity relation of the form M ~ V^4 that forms the basis for the observed luminosity-rotation velocity relation-- the Tully-Fisher law. We review the phenomenological success of MOND on scales ranging from dwarf spheroidal galaxies to superclusters, and demonstrate that the evidence for dark matter can be equally well interpreted as evidence for MOND. We discuss the possible physical basis for an acceleration-based modification of Newtonian dynamics as well as the extension of MOND to cosmology and structure formation.Comment: To be published in volume 40 of Annual Reviews of Astronomy & Astrophysics. 36 pages plus 12 figures and 1 tabl

Super-resolving phase measurements with a multi-photon entangled state

Using a linear optical elements and post-selection, we construct an entangled polarization state of three photons in the same spatial mode. This state is analogous to a ``photon-number path entangled state'' and can be used for super-resolving interferometry. Measuring a birefringent phase shift, we demonstrate two- and three-fold improvements in phase resolution.Comment: 4 pages, 3 figure

Fake people, real effects : the presence of virtual onlookers can impair performance and learning

Can effects of social influence be elicited in virtual contexts, and if so, under which conditions can they be observed? Answering these questions has theoretical merit, as the answers can help broaden our understanding of the interaction mechanisms described by social psychology. The increasing popularity of immersive media in training applications, however, has made these questions of practical significance. Virtual reality (VR), in particular, is a weapon of choice in designing training and education simulations, as it can be used to generate highly realistic characters and environments. As a consequence, it is key to understand under which circumstances virtual ‘others’ can facilitate or impede performance and – especially – learning. In this study, we investigated the impact of virtual onlookers on an adapted Serial Reaction Time (SRT) task that was presented in VR. In each trial, participants responded to a series of spherical stimuli by tapping them with handheld controllers when they lit up. Depending on the experiment block, the sequence order was either the permutation of a fixed order (and therefore predictable given the first stimulus), or fully random (and therefore unpredictable). Participants were divided into three groups (audience variable), depending on the environment in which the task was set: a group without onlookers (none condition), a group with a computer-generated audience (CGI condition), and a group being watched by a prerecorded audience (filmed condition). Results showed that the presence of a virtual audience can hamper both overall performance and learning, particularly when the audience appears more realistic. This study further reinforces the notion that the effects of social influence transcend the physical presence of others, but rather extend to virtual audiences

Oral diagnosis and treatment planning: Part 6. Preventive and treatment planning for periodontal disease

A high level of sustained personal plaque control is fundamental for successful treatment outcomes in patients with active periodontal disease and, hence, oral hygiene instructions are the cornerstone of periodontal treatment planning. Other risk factors for periodontal disease also should be identified and modified where possible. Many restorative dental treatments in particular require the establishment of healthy periodontal tissues for their clinical success. Failure by patients to control dental plaque because of inappropriate designs and materials for restorations and prostheses will result in the long-term failure of the restorations and the loss of supporting tissues. Periodontal treatment planning considerations are also very relevant to endodontic, orthodontic and osseointegrated dental implant conditions and proposed therapies.E. Corbet and R. Smale

Telomeric expression sites are highly conserved in trypanosoma brucei

Subtelomeric regions are often under-represented in genome sequences of eukaryotes. One of the best known examples of the use of telomere proximity for adaptive purposes are the bloodstream expression sites (BESs) of the African trypanosome Trypanosoma brucei. To enhance our understanding of BES structure and function in host adaptation and immune evasion, the BES repertoire from the Lister 427 strain of T. brucei were independently tagged and sequenced. BESs are polymorphic in size and structure but reveal a surprisingly conserved architecture in the context of extensive recombination. Very small BESs do exist and many functioning BESs do not contain the full complement of expression site associated genes (ESAGs). The consequences of duplicated or missing ESAGs, including ESAG9, a newly named ESAG12, and additional variant surface glycoprotein genes (VSGs) were evaluated by functional assays after BESs were tagged with a drug-resistance gene. Phylogenetic analysis of constituent ESAG families suggests that BESs are sequence mosaics and that extensive recombination has shaped the evolution of the BES repertoire. This work opens important perspectives in understanding the molecular mechanisms of antigenic variation, a widely used strategy for immune evasion in pathogens, and telomere biology

Facilitative parenting and children's social, emotional and behavioural adjustment

Facilitative parenting (FP) supports the development of children’s social and emotional competence and effective peer relationships. Previous research has shown that FP discriminates between children bullied by peers from children who are not bullied, according to reports of teachers. This study investigates the association between FP and children’s social, emotional and behavioral problems, over and above the association with dysfunctional parenting (DP). 215 parents of children aged 5–11 years completed questionnaires about parenting and child behavior, and children and teachers completed measures of child bullying victimization. As predicted, FP accounted for variance in teacher reports of children’s bullying victimization as well as parent reports of children’s social and emotional problems and prosocial behavior better than that accounted for by DP. However for children’s reports of peer victimization the whole-scale DP was a better predictor than FP. Contrary to predictions, FP accounted for variance in conduct problems and hyperactivity better than DP. When analyses were replicated substituting subscales of dysfunctional and FP, a sub-set of FP subscales including Warmth, Supports Friendships, Not Conflicting, Child Communicates and Coaches were correlated with low levels of problems on a broad range of children’s adjustment problems. Parent–child conflict accounted for unique variance in children’s peer victimization (teacher report), peer problems, depression, emotional problems, conduct problems and hyperactivity. The potential relevance of FP as a protective factor for children against a wide range of adjustment problems is discussed

Spin Caloritronics

This is a brief overview of the state of the art of spin caloritronics, the science and technology of controlling heat currents by the electron spin degree of freedom (and vice versa).Comment: To be published in "Spin Current", edited by S. Maekawa, E. Saitoh, S. Valenzuela and Y. Kimura, Oxford University Pres

What we talk about when we talk about "global mindset": managerial cognition in multinational corporations

Recent developments in the global economy and in multinational corporations have placed significant emphasis on the cognitive orientations of managers, giving rise to a number of concepts such as “global mindset” that are presumed to be associated with the effective management of multinational corporations (MNCs). This paper reviews the literature on global mindset and clarifies some of the conceptual confusion surrounding the construct. We identify common themes across writers, suggesting that the majority of studies fall into one of three research perspectives: cultural, strategic, and multidimensional. We also identify two constructs from the social sciences that underlie the perspectives found in the literature: cosmopolitanism and cognitive complexity and use these two constructs to develop an integrative theoretical framework of global mindset. We then provide a critical assessment of the field of global mindset and suggest directions for future theoretical and empirical research