A parent-centered radial layout algorithm for interactive graph visualization and animation

We have developed (1) a graph visualization system that allows users to explore graphs by viewing them as a succession of spanning trees selected interactively, (2) a radial graph layout algorithm, and (3) an animation algorithm that generates meaningful visualizations and smooth transitions between graphs while minimizing edge crossings during transitions and in static layouts. Our system is similar to the radial layout system of Yee et al. (2001), but differs primarily in that each node is positioned on a coordinate system centered on its own parent rather than on a single coordinate system for all nodes. Our system is thus easy to define recursively and lends itself to parallelization. It also guarantees that layouts have many nice properties, such as: it guarantees certain edges never cross during an animation. We compared the layouts and transitions produced by our algorithms to those produced by Yee et al. Results from several experiments indicate that our system produces fewer edge crossings during transitions between graph drawings, and that the transitions more often involve changes in local scaling rather than structure. These findings suggest the system has promise as an interactive graph exploration tool in a variety of settings

A framework for measuring quality in the emergency department

There is increasing concern that medical care is of variable quality, with variable outcomes, safety, costs and experience for patients. Despite substantial efforts to improve patient safety, some studies suggest little evidence of reductions in adverse events. Furthermore, there is limited agreement about what outcomes are expected and whether increased expenditure results in a real improvement in outcome or experience. In emergency medicine, many countries have developed specific indicators to help drive improvements in patient care. Most of these are time based and there is a lack of consensus regarding which indicators are high priority and what an appropriate framework for measuring quality should look like

Reply to the comment by Carmelo Anile on the paper "Complexity analysis of the cerebrospinal fluid pulse waveform during infusion studies"

Veterinary technology is an emerging profession within the veterinary and allied animal health fields in Australia and affords graduates the opportunity to contribute to the small but growing body of literature within this discipline. This study describes the introduction of a contextualised assessment task to develop students’ research capability, competence and confidence in professional writing, and to engage them with the academic publishing process. Students worked in self-selected dyads to author a scientific case report, of publishable standard, based on authentic cases from their clinical practicum. Intrinsic to the task, students attended a series of workshops that explored topics such as critiquing the literature, professional writing styles and oral presentation skills. Assessment was multi-staged with progressive feedback, including peer review, and culminated with students presenting their abstracts at a mock conference. Students reported the task to be an enjoyable and valuable learning experience which improved their competence and confidence in scientific writing; supported by a comparison of previously submitted work. Linking scientific writing skills to clinical practice experiences enhanced learning outcomes and may foster the professionalisation of students within this emerging discipline

Imaging isodensity contours of molecular states with STM

We present an improved way for imaging the local density of states with a scanning tunneling microscope, which consists in mapping the surface topography while keeping the differential conductance (d$I$/d$V$) constant. When archetypical C$_{60}$ molecules on Cu(111) are imaged with this method, these so-called iso-d$I$/d$V$ maps are in excellent agreement with theoretical simulations of the isodensity contours of the molecular orbitals. A direct visualization and unambiguous identification of superatomic C$_{60}$ orbitals and their hybridization is then possible

Optical Probe of Quantum Shot Noise Reduction at a Single-Atom Contact

Visible and infra-red light emitted at a Ag-Ag(111) junction has been investigated from tunneling to single atom contact conditions with a scanning tunneling microscope. The light intensity varies in a highly nonlinear fashion with the conductance of the junction and exhibits a minimum at conductances close to the conductance quantum. The data are interpreted in terms of current noise at optical frequencies, which is characteristic of partially open transport channels

Electroluminescence from a polythiophene molecular wire suspended in a plasmonic scanning tunneling microscope junction

The electroluminescence of a polythiophene wire suspended between two metallic electrodes is probed using a scanning tunneling microscope. Under positive sample voltage, the spectral and voltage dependencies of the emitted light are consistent with the fluorescence of the wire junction mediated by localized plasmons. This emission is strongly attenuated for the opposite polarity. Both emission mechanism and polarity dependence are similar to what occurs in organic light emitting diodes (OLED) but at the level of a single molecular wire.Comment: to be published in Physical Review Letter

The oxidative debt of fasting : evidence for short to medium-term costs of advanced fasting in adult king penguins

This research was funded by the French Polar Institute (IPEV–Research Program 119) and the French National Centre for Scientific Research (CNRS-INEE). We are especially grateful to Dominic L. Cram and one anonymous reviewer for helpful comments on the paper. Field logistic support was provided by Terres Australes et Antarctiques Françaises. QS was funded by a doctoral fellowship from the Ministère Français de l’Education Supérieur et de la Recherche.Peer reviewedPublisher PD

Microchip Capillary Electrophoresis

For the study of neuromodulation in Cancer borealis we have designed a microfluidic device to separate and detect bioamine concentrations with a high temporal resolution. Our goal is to use this device to measure the concentration of continuous bioamine microdialysis samples directly from the pericardial cavity (the area surrounding the heart) of Cancer borealis. The microfluidic device that we designed is made from polydimethylsiloxane (PDMS) and exhibits an off-channel configuration of capillary electrophoresis (CE) by incorporating micellar electrokinetic chromatography (MEKC). CE is used to separate bioamines based on charge and size due to the applied electrical potential. In the off-channel configuration, the potential is applied across the separation channel and grounded by the palladium decoupler, which lies just before the detector. Microchip CE is advantageous because it uses small amounts of analyte and completes fast run times. We will use MEKC to separate dopamine and octopamine, since they are structural isomers, by their difference in affinity to sodium dodecyl sulfate (SDS) micelles. This results in different elution times for dopamine and octopamine. We were able to drive the fluid in the correct direction. The creation of this device has valuable implications, allowing for baseline concentrations of neuromodulators with the Cancer borealis to be established. The effect of different stimuli on these crabs can then be more accurately determined

Passing Current through Touching Molecules

The charge flow from a single C60 molecule to another one has been probed. The conformation and electronic states of both molecules on the contacting electrodes have been characterized using a cryogenic scanning tunneling microscope. While the contact conductance of a single molecule between two Cu electrodes can vary up to a factor of three depending on electrode geometry, the conductance of the C60-C60 contact is consistently lower by two orders of magnitude. First-principles transport calculations reproduce the experimental results, allow a determination of the actual C60-C60 distances, and identify the essential role of the intermolecular link in bi- and trimolecular chains.Comment: 4 pages, 4 figures (+ suppl. material 2 pages, 1 figure