On phase behavior and dynamical signatures of charged colloidal platelets

We investigate the competition between anisotropic excluded-volume and repulsive electrostatic interactions in suspensions of thin charged colloidal discs, by means of Monte-Carlo simulations and dynamical characterization of the structures found. We show that the original intrinsic anisotropy of the electrostatic potential between charged platelets, obtained within the non-linear Poisson-Boltzmann formalism, not only rationalizes the generic features of the complex phase diagram of charged colloidal platelets such as Gibbsite and Beidellite clays, but also predicts the existence of novel structures. In addition, we find evidences of a strong slowing down of the dynamics upon increasing density.Comment: 6 pages, 6 Figure

Environmental Problems of Space Flight Structures. 2. Meteoroid Hazard

Environmental problems of space flight structures - part 2, meteoroid hazard

Watch Out for the Beast: Fear Information and Attentional Bias in Children

Although valenced information about novel animals changes the implicit and explicit fear beliefs of children (Field & Lawson, 2003), how it might lead to anxiety is unknown. One possibility, based on cognitive models of anxiety, is that fear information creates attentional biases similar to those seen in anxiety disorders. Children between 7 and 9 years old were given positive information about 1 novel animal, negative information about another, and no information about the 3rd. A pictorial dot-probe task was used, immediately or with a 24-hr delay, to test for attentional biases to the different animals. The results replicated the finding that fear information changes children's fear beliefs. Regardless of whether there was a delay, children acquired an attentional bias in the left visual field toward the animal about which they held negative beliefs compared to the control animal. These results imply a possible way in which fear information might contribute to acquired fear

On the He II Emission In Eta Carinae and the Origin of Its Spectroscopic Events

We describe and analyze Hubble Space Telescope (HST) observations of transient emission near 4680 {\AA} in Eta Car, reported earlier by Steiner & Damineli (2004). If, as seems probable, this is He II $\lambda$4687, then it is a unique clue to Eta Car's 5.5-year cycle. According to our analysis, several aspects of this feature support a mass-ejection model of the observed spectroscopic events, and not an eclipse model. The He II emission appeared in early 2003, grew to a brief maximum during the 2003.5 spectroscopic event, and then abruptly disappeared. It did not appear in any other HST spectra before or after the event. The peak brightness was larger than previously reported, and is difficult to explain even if one allows for an uncertainty factor of order 3. The stellar wind must provide a temporary larger-than-normal energy supply, and we describe a special form of radiative amplification that may also be needed. These characteristics are consistent with a class of mass-ejection or wind-disturbance scenarios, which have implications for the physical structure and stability of Eta Car.Comment: 47 pages (including all appendices, tabs, & figs), 9 figures, 3 tables; submitted to Astrophysical Journal (2005 March 29), accepted for publication in Ap

Advance care planning in 21st century Australia: a systematic review and appraisal of online advance care directive templates against national framework criteria

Objectives A drive to promote advance care planning at a population level has led to a proliferation of online advance care directive (ACD) templates but little information to guide consumer choice. The current study aimed to appraise the quality of online ACD templates promoted for use in Australia. Methods A systematic review of online Australian ACD templates was conducted in February 2014. ACD templates were identified via Google searches, and quality was independently appraised by two reviewers against criteria from the 2011 report A National Framework for Advance Care Directives. Bias either towards or against future medical treatment was assessed using criteria designed to limit subjectivity. Results Fourteen online ACD templates were included, all of which were available only in English. Templates developed by Southern Cross University best met the framework criteria. One ACD template was found to be biased against medical treatment – the Dying with Dignity Victoria Advance Healthcare Directive. Conclusions More research is needed to understand how online resources can optimally elicit and record consumers’ individual preferences for future care. Future iterations of the framework should address online availability and provide a simple rating system to inform choice and drive quality improvement

On the formation of cyclones and anticyclones in a rotating fluid

It is commonly observed that the columnar vortices that dominate the large scales in homogeneous, rapidly rotating turbulence are predominantly cyclonic. This has prompted us to ask how this asymmetry arises. To provide a partial answer to this we look at the process of columnar vortex formation in a rotating fluid and, in particular, we examine how a localized region of swirl (an eddy) can convert itself into a columnar structure by inertial wave propagation. We show that, when the Rossby number (Ro) is small, the vortices evolve into columnar eddies through the radiation of linear inertial waves. When the Rossby number is large, on the other hand, no such column is formed. Rather, the eddy bursts radially outward under the action of the centrifugal force. There is no asymmetry between cyclonic and anticyclonic eddies for these two regimes. However, cyclones and anticyclones behave differently in the intermediate regime of Ro~1. Here we find that the transition from columnar vortex formation to radial bursting occurs at lower values of Ro for anticyclones, with the transition for anticyclones occurring at Ro~0.5, and that for cyclones at Ro~2. Thus, in a homogeneous turbulence experiment conducted at, say, Ro=1, we would expect to see more cyclones than anticyclones. The reason for this asymmetry at Ro~1 is explained

Kohn-Sham calculations combined with an average pair-density functional theory

A recently developed formalism in which Kohn-Sham calculations are combined with an ``average pair density functional theory'' is reviewed, and some new properties of the effective electron-electron interaction entering in this formalism are derived. A preliminary construction of a fully self-consitent scheme is also presented in this framework.Comment: submitted to Int. J. Mod. Phys. B (proceedings of the 30th International Workshop on Condensed Matter Theories

Spectrum Orbit Utilization Program Documentation: SOUP5 Version 3.8 User's Manual, Volume 2, Appendices a Through G

The appendixes of the user manual are presented. Input forms which may be used to prepare data for the SOUP5V3.4 of the R2BCSAT-83 data base are given. The IBM job control language which can be used to run the SOUP5 system from a magnetic tape is described. Copies of a run using the delivered tape and IBM OS/MVS Job Control Language card deck are illustrated. Numerical limits on scenario data requests are listed. Error handling, error messages and editing procedures are also listed. Instructions as to how to enter a protection ratio template are given. And relation between PARC prameter, channelization, channel families, and interference categories are also listed

Sr Isotope Zoning in Plagioclase from Parinacota Volcano (Northern Chile): Quantifying Magma Mixing and Crustal Contamination

We present analyses of Sr isotope zoning by microdrilling and thermal ionization mass spectrometry in plagioclase crystals from Parinacota volcano (Central Volcanic Zone, northern Chile), which were analysed for major and minor element zoning in a previous study. Although the isotopic range of the bulk-rock samples is small at this volcano (0·7067-0·7070, except for one flow of mafic andesite at 0·7061), significant variations are seen (0·70649-0·70700) within and between plagioclase crystals. A general negative correlation is observed between Sr isotope composition and Sr concentration in the liquid in equilibrium with each plagioclase zone, as calculated from chemical zoning data and partition coefficients. Additional scatter is superimposed on this general trend, indicating a decoupling between isotopic and chemical variations for Sr. In one dacite sample a detailed isotopic profile shows increasing contamination during crystal growth, except for an abrupt decrease correlated with a dissolution surface and interpreted as a recharge event. We apply energy-constrained recharge, assimilation and fractional crystallization modelling to the melt evolution recorded in the chemical and isotopic zoning in this crystal. Results suggest 20% assimilation of the local wall-rock gneiss, at high initial temperatures. The isotopic data confirm the involvement of two contrasting mafic magmas, which are sampled at flank cinder cone vents. One (Lower Ajata) has a low Sr content with high 87Sr/86Sr, the other (Upper Ajata) has a high Sr content with lower 87Sr/86Sr. In some samples from Parinacota, the isotopic composition of plagioclase crystal rims or groundmass crystals is significantly higher than that of the high 87Sr/86Sr mafic magma. In others, where chemical zoning profiles suggest that recharge was from the low 87Sr/86Sr magma, the 87Sr/86Sr of the groundmass and crystal rims is higher than expected. This indicates either additional parent magmas to the two previously identified, or further crustal assimilation, either at lower crustal depths, before crystallization of plagioclase, or just after the last recharge. Our results illustrate the complexity of magma-crust interaction beneath Parinacota, which is likely to be representative of many other Central Andean volcanoes formed on thick crust. Such complex interactions can be revealed by combined study of chemical and isotopic zoning in plagioclase (in a textural petrographic context), despite a small whole-rock isotopic range. The distinct contamination patterns of various samples suggest an important role for the geometry, location and evolution of the magma plumbing system and, in general, variations of the thermal and compositional structure of the crust underneath the volcan