Electronic learning can facilitate student performance in undergraduate surgical education: a prospective observational study

BACKGROUND: Our institution recently introduced a novel internet accessible computer aided learning (iCAL) programme to complement existing surgical undergraduate teaching methods. On graduation of the first full cycle of undergraduate students to whom this resource was available we assessed the utility of this new teaching facility. METHOD: The computer programme prospectively records usage of the system on an individual user basis. We evaluated the utilisation of the web-based programme and its impact on class ranking changes from an entry-test evaluation to an exit examination in surgery. RESULTS: 74.4% of students were able to access iCAL from off-campus internet access. The majority of iCAL usage (64.6%) took place during working hours (08:00–18:00) with little usage on the weekend (21.1%). Working hours usage was positively associated with improvement in class rank (P = 0.025, n = 148) but out-of hours usage was not (P = 0.306). Usage during weekdays was associated with improved rank (P = 0.04), whereas weekend usage was not (P = 0.504). There were no significant differences in usage between genders (P = 0.3). Usage of the iCAL system was positively correlated with improvement in class rank from the entry to the exit examination (P = 0.046). Students with lower ranks on entry examination, were found to use the computer system more frequently (P = 0.01). CONCLUSION: Electronic learning complements traditional teaching methods in undergraduate surgical teaching. Its is more frequently used by students achieving lower class ranking with traditional teaching methods, and this usage is associated with improvements in class ranking

Towards Quantum Repeaters with Solid-State Qubits: Spin-Photon Entanglement Generation using Self-Assembled Quantum Dots

In this chapter we review the use of spins in optically-active InAs quantum dots as the key physical building block for constructing a quantum repeater, with a particular focus on recent results demonstrating entanglement between a quantum memory (electron spin qubit) and a flying qubit (polarization- or frequency-encoded photonic qubit). This is a first step towards demonstrating entanglement between distant quantum memories (realized with quantum dots), which in turn is a milestone in the roadmap for building a functional quantum repeater. We also place this experimental work in context by providing an overview of quantum repeaters, their potential uses, and the challenges in implementing them.Comment: 51 pages. Expanded version of a chapter to appear in "Engineering the Atom-Photon Interaction" (Springer-Verlag, 2015; eds. A. Predojevic and M. W. Mitchell

Quantum Computing

Quantum mechanics---the theory describing the fundamental workings of nature---is famously counterintuitive: it predicts that a particle can be in two places at the same time, and that two remote particles can be inextricably and instantaneously linked. These predictions have been the topic of intense metaphysical debate ever since the theory's inception early last century. However, supreme predictive power combined with direct experimental observation of some of these unusual phenomena leave little doubt as to its fundamental correctness. In fact, without quantum mechanics we could not explain the workings of a laser, nor indeed how a fridge magnet operates. Over the last several decades quantum information science has emerged to seek answers to the question: can we gain some advantage by storing, transmitting and processing information encoded in systems that exhibit these unique quantum properties? Today it is understood that the answer is yes. Many research groups around the world are working towards one of the most ambitious goals humankind has ever embarked upon: a quantum computer that promises to exponentially improve computational power for particular tasks. A number of physical systems, spanning much of modern physics, are being developed for this task---ranging from single particles of light to superconducting circuits---and it is not yet clear which, if any, will ultimately prove successful. Here we describe the latest developments for each of the leading approaches and explain what the major challenges are for the future.Comment: 26 pages, 7 figures, 291 references. Early draft of Nature 464, 45-53 (4 March 2010). Published version is more up-to-date and has several corrections, but is half the length with far fewer reference

"Being in a Knowledge Space": information behaviour of cult media fan communities

This article describes the first two parts of a three-stage study investigating the information behaviour of fans and fan communities, focusing on fans of cult media. A literature analysis shows that information practices are an inherent and major part of fan activities, and that fans are practitioners of new forms of information consumption and production, showing sophisticated activities of information organisation and dissemination. A subsequent Delphi study, taking the novel form of a 'serious leisure' Delphi, in which the participants are not experts in the usual sense, identifies three aspects of fan information behaviour of particular interest beyond the fan context: information gatekeeping; classifying and tagging; and entrepreneurship and economic activity

Global Priorities for Conserving the Evolutionary History of Sharks, Rays, and Chimaeras

In an era of accelerated biodiversity loss and limited conservation resources, systematic prioritization of species and places is essential. In terrestrial vertebrates, evolutionary distinctness has been used to identify species and locations that embody the greatest share of evolutionary history. We estimate evolutionary distinctness for a large marine vertebrate radiation on a dated taxon-complete tree for all 1,192 chondrichthyan fishes (sharks, rays and chimaeras) by augmenting a new 610-species molecular phylogeny using taxonomic constraints. Chondrichthyans are by far the most evolutionarily distinct of all major radiations of jawed vertebrates—the average species embodies 26 million years of unique evolutionary history. With this metric, we identify 21 countries with the highest richness, endemism and evolutionary distinctness of threatened species as targets for conservation prioritization. On average, threatened chondrichthyans are more evolutionarily distinct—further motivating improved conservation, fisheries management and trade regulation to avoid significant pruning of the chondrichthyan tree of life

Phylogeographic pattern and extensive mitochondrial DNA divergence disclose a species complex within the Chagas disease vector Triatoma dimidiata.

ABSTARCT: Previous studies have shown that "bioequivalent" generic products of vancomycin are less effective in vivo against Staphylococcus aureus than the innovator compound. Considering that suboptimal bactericidal effect has been associated with emergence of resistance, we aimed to assess in vivo the impact of exposure to innovator and generic products of vancomycin on S. aureus susceptibility. A clinical methicillin-resistant S. aureus (MRSA) strain from a liver transplant patient with persistent bacteremia was used for which MIC, minimum bactericidal concentration (MBC), and autolytic properties were determined. Susceptibility was also assessed by determining a population analysis profile (PAP) with vancomycin concentrations from 0 to 5 mg/liter. ICR neutropenic mice were inoculated in each thigh with ∼7.0 log(10) CFU. Treatment with the different vancomycin products (innovator and three generics; 1,200 mg/kg of body weight/day every 3 h) started 2 h later while the control group received sterile saline. After 24 h, mice were euthanized, and the thigh homogenates were plated. Recovered colonies were reinoculated to new groups of animals, and the exposure-recovery process was repeated until 12 cycles were completed. The evolution of resistance was assessed by PAP after cycles 5, 10, 11, and 12. The initial isolate displayed reduced autolysis and higher resistance frequencies than S. aureus ATCC 29213 but without vancomycin-intermediate S. aureus (VISA) subpopulations. After 12 cycles, innovator vancomycin had significantly reduced resistant subpopulations at 1, 2, and 3 mg/liter, while the generic products had enriched them progressively by orders of magnitude. The great capacity of generic vancomycin to select for less susceptible organisms raises concerns about the role of therapeutic inequivalence of any antimicrobial on the epidemiology of resistance worldwide

Phylogeography of Aegean green toads (Bufo viridis subgroup): continental hybrid swarm vs. insular diversification with discovery of a new island endemic

BACKGROUND: Debated aspects in speciation research concern the amount of gene flow between incipient species under secondary contact and the modes by which post-zygotic isolation accumulates. Secondary contact zones of allopatric lineages, involving varying levels of divergence, provide natural settings for comparative studies, for which the Aegean (Eastern Mediterranean) geography offers unique scenarios. In Palearctic green toads (Bufo viridis subgroup or Bufotes), Plio-Pleistocene (~ 2.6 Mya) diverged species show a sharp transition without contemporary gene flow, while younger lineages, diverged in the Lower-Pleistocene (~ 1.9 Mya), admix over tens of kilometers. Here, we conducted a fine-scale multilocus phylogeographic analysis of continental and insular green toads from the Aegean, where a third pair of taxa, involving Mid-Pleistocene diverged (~ 1.5 Mya) mitochondrial lineages, earlier tentatively named viridis and variabilis, (co-)occurs. RESULTS: We discovered a new lineage, endemic to Naxos (Central Cyclades), while coastal islands and Crete feature weak genetic differentiation from the continent. In continental Greece, both lineages, viridis and variabilis, form a hybrid swarm, involving massive mitochondrial and nuclear admixture over hundreds of kilometers, without obvious selection against hybrids. CONCLUSIONS: The genetic signatures of insular Aegean toads appear governed by bathymetry and Quaternary sea level changes, resulting in long-term isolation (Central Cyclades: Naxos) and recent land-bridges (coastal islands). Conversely, Crete has been isolated since the end of the Messinian salinity crisis (5.3 My) and Cretan populations thus likely result from human-mediated colonization, at least since Antiquity, from Peloponnese and Anatolia. Comparisons of green toad hybrid zones support the idea that post-zygotic hybrid incompatibilities accumulate gradually over the genome. In this radiation, only one million years of divergence separate a scenario of complete reproductive isolation, from a secondary contact resulting in near panmixia

Asymmetric reproductive isolation between terminal forms of the salamander ring species Ensatina eschscholtzii revealed by fine-scale genetic analysis of a hybrid zone

<p>Abstract</p> <p>Background</p> <p>Ring species, exemplified by salamanders of the <it>Ensatina eschscholtzii </it>complex, represent a special window into the speciation process because they allow the history of species formation to be traced back in time through the geographically differentiated forms connecting the two terminal forms of the ring. Of particular interest is the nature and extent of reproductive isolation between the geographically terminal forms, in this case <it>E. e. eschscholtzii </it>and <it>E. e. klauberi</it>. Previous studies have documented infrequent hybridization at the end of the ring. Here, we report the first fine-scale genetic analysis of a hybrid zone between the terminal forms in southern California using individual-based Bayesian analyses of multilocus genetic data to estimate levels and direction of hybridization and maximum-likelihood analysis of linkage disequilibrium and cline shape to make inferences about migration and selection in the hybrid zone.</p> <p>Results</p> <p>The center of the hybrid zone has a high proportion of hybrids, about half of which were classified as F1s. Clines are narrow with respect to dispersal, and there are significant deviations from Hardy-Weinberg equilibrium as well as nonrandom associations (linkage disequilibria) between alleles characteristic of each parental type. There is cytonuclear discordance, both in terms of introgression and the geographic position of mitochondrial versus nuclear clines. Genetic disequilibrium is concentrated on the <it>eschscholtzii </it>side of the zone. Nearly all hybrids possess <it>klauberi </it>mtDNA, indicating that most hybrids are formed from female <it>klauberi </it>mating with male <it>eschscholtzii </it>or male hybrids (but not vice versa).</p> <p>Conclusions</p> <p>Our results are consistent with a tension zone trapped at an ecotone, with gene combinations characteristic of <it>klauberi </it>showing up on the <it>eschscholtzii </it>side of the zone due to asymmetric hybridization. We suggest that the observed asymmetry is best explained by increased discriminatory power of <it>eschscholtzii </it>females, or asymmetric postzygotic isolation. The relatively high frequency of hybrids, particularly F1s, contrasts with other contacts between the terminal forms, and with other contacts between other divergent <it>Ensatina </it>lineages, highlighting the diverse outcomes of secondary contact within a single species complex.</p

A prospective investigation of rumination and executive control in predicting overgeneral autobiographical memory in adolescence

The CaR-FA-X model (Williams et al., 2007), or capture and rumination (CaR), functional avoidance (FA) and impaired executive control (X), is a model of overgeneral autobiographical memory. Two mechanisms of the model, rumination and executive control were examined in isolation and in interaction to investigate overgeneral autobiographical memory over time. Method: Across two time points, six months apart, a total of 149 adolescents (13-16 years) completed a minimal instruction autobiographical memory test, a measure of executive control with emotional and non-emotional stimuli, and measures of brooding rumination and reflective pondering. Results: It was found that executive control for emotional information was negatively associated with OGM, but only when reflective pondering levels were high. Conclusion: In the context of higher levels of reflective pondering, greater switch costs (i.e. lower executive control) when processing emotional information predict a decrease in OGM over time