Nonlinear Integrable Ion Traps

Quadrupole ion traps can be transformed into nonlinear traps with integrable motion by adding special electrostatic potentials. This can be done with both stationary potentials (electrostatic plus a uniform magnetic field) and with time-dependent electric potentials. These potentials are chosen such that the single particle Hamilton-Jacobi equations of motion are separable in some coordinate systems. The electrostatic potentials have several free adjustable parameters allowing for a quadrupole trap to be transformed into, for example, a double-well or a toroidal-well system. The particle motion remains regular, non-chaotic, integrable in quadratures, and stable for a wide range of parameters. We present two examples of how to realize such a system in case of a time-independent (the Penning trap) as well as a time-dependent (the Paul trap) configuration

Addressing Ethical Issues in Studying Men’s Traumatic Stress

Like many human experiences, traumatic stress is highly gendered. Over the past several decades, a sub-stantial number of empirical studies have explored ethical issues in traumatic stress research. However, these studies have typically reported female samples or failed to account for the influence of gender in their analyses of mixed-sex samples. By extension, ethical issues that are relevant to male participants in traumatic stress research are poorly understood. After briefly exploring why the vulnerabilities of male participants are under-explored in traumatic stress research, this article highlights many ethical issues that are important to address when men participate in traumatic stress research, concluding with some sugges-tions for how these might be taken up to advance the field

Self-care and entrepreneurism: An ethnography of soft skills development for higher education staff

Despite the ubiquity of staff soft skills programmes, few studies have examined why and how academic and corporate services staff utilise these programmes for self-care/governance. This study reports on findings from an ethnography of soft-skills learning and development programmes (LDPs) in a UK university, focusing on interviews with programme participants and facilitators. Results suggest that, as social worlds with neoliberal directives, LDPs promote various self-governance activities in the form of entrepreneurism and novel, corporate versions of self-care. Time on LDPs was seen as a chance to, ‘put oneself first,’ examine career options and cultivate sought-after attributes, including self-confidence and assertiveness. Social networking and performance management also emerged as significant issues. Career development was important for all participants; however, perceptions of how to realise this differed. Based on our findings, we propose three types of work-related performance – ‘career nomad,’ ‘reluctant entrepreneur,’ and ‘course hopper’ – constituting a typology for understanding social worlds inhabited by contemporary university professionals. Our study suggests that self-care ‘technologies’ have multiple, competing functions in continuing professional education. While LDPs can help professionals navigate paths through increasingly turbulent organisations, their entrepreneurial ethos and content reflect the market interests they serve

The Near-Infrared Extinction Law in Regions of High Av

We present a spectroscopic study of the shape of the dust-extinction law between 1.0 and 2.2um towards a set of nine ultracompact HII regions with Av > 15 mag. We find some evidence that the reddening curve may tend to flatten at higher extinctions, but just over half of the sample has extinction consistent with or close to the average for the interstellar medium. There is no evidence of extinction curves significantly steeper than the standard law, even where water ice is present. Comparing the results to the predictions of a simple extinction model, we suggest that a standard extinction law implies a robust upper limit to the grain-size distribution at around 0.1 - 0.3um. Flatter curves are most likely due to changes in this upper limit, although the effects of flattening due to unresolved clumpy extinction cannot be ruled out.Comment: 9 pages, 7 figure

Ring for test of nonlinear integrable optics

Nonlinear optics is a promising idea potentially opening the path towards achieving super high beam intensities in circular accelerators. Creation of a tune spread reaching 50% of the betatron tune would provide strong Landau damping and make the beam immune to instabilities. Recent theoretical work has identified a possible way to implement stable nonlinear optics by incorporating nonlinear focusing elements into a specially designed machine lattice. In this report we propose the design of a test accelerator for a proof-of-principle experiment. We discuss possible studies at the machine, requirements on the optics stability and sensitivity to imperfections.Comment: 3 pp. Particle Accelerator, 24th Conference (PAC'11) 28 Mar - 1 Apr 2011: New York, US

Helium and Hydrogen Line Ratios and The Stellar Content of Compact HII Regions

We present observations and models of the behaviour of the HI and HeI lines between 1.6 and 2.2um in a small sample of compact HII regions. As in our previous papers on planetary nebulae, we find that the `pure' 1.7007um 4^3D-3^3P and 2.16475um 7^(3,1)G-4^(3,1)F HeI recombination lines behave approximately as expected as the effective temperature of the central exciting star(s) increases. However, the 2.058um 2^1P-2^1S HeI line does not behave as the model predicts, or as seen in planetary nebulae. Both models and planetary nebulae showed a decrease in the HeI 2^1P-2^1S/HI Br gamma ratio above an effective temperature of 40000K. The compact HII regions do not show any such decrease. The problem with this line ratio is probably due to the fact that the photoionisation model does not account correctly for the high densities seen in these HII regions, and that we are therefore seeing more collisional excitation of the 2^1P level than the model predicts. It may also reflect some deeper problem in the assumed model stellar atmospheres. In any event, although the normal HeI recombination lines can be used to place constraints on the temperature of the hottest star present, the HeI 2^1P-2^1S/HI Br gamma ratio should not be used for this purpose in either Galactic HII regions or in starburst galaxies, and conclusions from previous work using this ratio should be regarded with extreme caution. We also show that the combination of the near infrared `pure' recombination line ratios with mid-infrared forbidden line data provides a good discriminant of the form of the far ultraviolet spectral energy distribution of the exciting star(s). From this we conclude that CoStar models are a poor match to the available data for our sources, though the more recent WM-basic models are a better fit.Comment: Accepted for publication in MNRA

A large conductance, Ca2+-activated K+ channel in a human lung epithelial cell line (A549)

AbstractA large conductance, Ca2+-activated K+ channel in a human lung epithelial cell line (A549) was identified using the single channel patch clamp technique. Channel conductance was 242±33 pS (n=67) in symmetrical KCl (140 mM). The channel was activated by membrane depolarization and increased cytosolic Ca2+. High selectivity was observed for K+ over Rb+(0.49)>Cs+(0.14)>Na+(0.09). Open probability was significantly decreased by Ba2+ (5 mM) and quinidine (5 mM) to either surface, but TEA (5 mM) was only effective when added to the external surface. All effects were reversible. Increasing cytosolic Ca2+ concentration from 10−7 to 10−6 M caused an increase in open probability from near zero to fully activated. ATP decreased open probability at ∼2 mM, but the effect was variable. The channel was almost always observed together with a smaller conductance channel, although they could both be seen individually. We conclude that A549 cells contain large conductance Ca2+-activated K+ channels which could explain a major fraction of the K+ conductance in human alveolar epithelial membranes

Care, control and the electroconvulsive therapy (ECT) ritual: Making sense of polarised patient narratives

Despite evidence of short-term effectiveness of ECT (electroconvulsive therapy), both positive and negative patient reports are common. However, research examining these polarized accounts has not adequately elucidated why such divergences occur. We thus sought to examine opposing patient narratives to better understand underlying meanings. Eighteen interviews were conducted with UK-based people who had experienced the treatment. Our analysis revealed that the quality of relations with staff, ECT artefacts (e.g. the ECT suite), and perceived outcomes all play a role in divergent accounts. Positive reflections on ECT emerged alongside narratives of trust in staff, comfort with ECT, and perception of sufficient personal control. Conversely, where negative evaluations of ECT predominated, there was anger associated with a lack of control, and a belief that ECT made little sense, and was linked to past abuses and/or the unacceptability of side effects. We discuss the implications of our findings for professionals