Synthesis and spectroscopic characterization of new mixed-metal, mixed-chalcogenide clusters [Fe<SUB>2</SUB>W(CO)<SUB>10</SUB>(μ<SUP>3</SUP>-Se)(μ<SUP>3</SUP>-E)](E = Te or S). Structures of [Fe<SUB>2</SUB>M(CO)<SUB>10</SUB>(μ<SUP>3</SUP>-Se)(μ<SUP>3</SUP>-E)](M = W, E = Se or Te; M = Mo, E = Se)

The room-temperature reaction of [Fe2(CO)6(μ-SeTe)] and [Fe2(CO)6(μ-SSe)] with freshly prepared [W(CO)5(thf)](thf = tetrahydrofuran) yielded the new mixed-metal, mixed-chalcogenide clusters [Fe2W(CO)10(μ3-Se)(μ3-E)](E = Te 1 or S 2). Compounds 1 and 2 were characterized by IR and 13C, 77Se and 125Te NMR spectroscopy. The crystal structure of 1 was elucidated by X-ray diffraction methods. The previously reported compounds [Fe2W(CO)10(μ3-Se)2]3 and [Fe2Mo(CO)10(μ3-Se)2]4 were further characterized by 77Se NMR spectroscopy and single-crystal X-ray analysis. Clusters 1, 3 and 4 are isostructural and isomorphous (in the solid state). The structure consists of square-pyramidal Fe2WSeTe, Fe2WSe2 and Fe2MoSe2 cores respectively, and in each case the heterometal atom (W for 1 and 3 and Mo for 4) occupies the apical site

Snap denaturation reveals dimerization by AraC-like protein Rns

Here we show that the Rns regulator of Escherichia coli dimerises in vivo and in vitro. Furthermore, we demonstrate that Rns forms aggregates in vitro and describe a methodology to ameliorate aggregation thus permitting the analysis of Rns by cross-linking

Evaluation of biogenic amines in the faeces of children with and without autism by LC-MS/MS

Previous researchers have postulated that gastrointestinal bacteria may contribute to the development and maintenance of Autism Spectrum Disorders (ASD). There is evidence based on quantitative evaluation of the gastrointestinal bacterial population in ASD that this is unlikely and an alternate mechanism will be examined where the bacteria may contribute to the development of ASD via their metabolic products and the role of biogenic amines (BAs) will be investigated. In humans, BAs influence a number of physiological processes via their actions as neurotransmitters, local hormones and gastric acid secretion. Various amines have been implicated in several medical conditions such as schizophrenia and colon cancer. To date, the relationship between BAs and autism has not been explored. This study has been designed to identify differences (and/or similarities) in the level of Bas in faecal samples of autistic children (without gastrointestinal dysfunction: n = 14; with gastrointestinal dysfunction; n = 21) and their neurotypical siblings (n = 35) by LC-MS/MS. Regardless of the diagnosis, severity of ASD and gastrointestinal dysfunction there were no significant differences found between the groups. The findings suggest that BAs in the gastrointestinal tract do not play a role in the pathophysiology of gastrointestinal dysfunction associated with ASD

On relaxation processes in collisionless mergers

We analyze N-body simulations of halo mergers to investigate the mechanisms responsible for driving mixing in phase-space and the evolution to dynamical equilibrium. We focus on mixing in energy and angular momentum and show that mixing occurs in step-like fashion following pericenter passages of the halos. This makes mixing during a merger unlike other well known mixing processes such as phase mixing and chaotic mixing whose rates scale with local dynamical time. We conclude that the mixing process that drives the system to equilibrium is primarily a response to energy and angular momentum redistribution that occurs due to impulsive tidal shocking and dynamical friction rather than a result of chaotic mixing in a continuously changing potential. We also analyze the merger remnants to determine the degree of mixing at various radii by monitoring changes in radius, energy and angular momentum of particles. We confirm previous findings that show that the majority of particles retain strong memory of their original kinetic energies and angular momenta but do experience changes in their potential energies owing to the tidal shocks they experience during pericenter passages. Finally, we show that a significant fraction of mass (~ 40%) in the merger remnant lies outside its formal virial radius and that this matter is ejected roughly uniformly from all radii outside the inner regions. This highlights the fact that mass, in its standard virial definition, is not additive in mergers. We discuss the implications of these results for our understanding of relaxation in collisionless dynamical systems.Comment: Version accepted for Publication in Astrophysical Journal, March 20, 2007, v685. Minor changes, latex, 14 figure

NHS commissioning practice and health system governance: a mixed-methods realistic evaluation

Background By 2010 English health policy-makers had concluded that the main NHS commissioners [primary care trusts (PCTs)] did not sufficiently control provider costs and performance. After the 2010 general election, they decided to replace PCTs with general practitioner (GP)-controlled Clinical Commissioning Groups (CCGs). Health-care commissioners have six main media of power for exercising control over providers, which can be used in different combinations (‘modes of commissioning’). Objectives To: elicit the programme theory of NHS commissioning policy and empirically test its assumptions; explain what shaped NHS commissioning structures; examine how far current commissioning practice allowed commissioners to exercise governance over providers; examine how commissioning practices differ in different types of commissioning organisation and for specific care groups; and explain what factors influenced commissioning practice and the relationships between commissioners and providers. Design Mixed-methods realistic evaluation, comprising: Leximancer and cognitive frame analyses of policy statements to elicit the programme theory of NHS commissioning policy; exploratory cross-sectional analysis of publicly available managerial data about PCTs; systematic comparison of case studies of commissioning in four English sites – including commissioning for older people at risk of unplanned hospital admission; mental health; public health; and planned orthopaedic surgery – and of English NHS commissioning practice with that of a German sick-fund and an Italian region (Lombardy); action learning sets, to validate the findings and draw out practical implications; and two framework analyses synthesising the findings and testing the programme theory empirically. Results In the four English case study sites, CCGs were formed by recycling former commissioning structures, relying on and maintaining the existing GP commissioning leaderships. The stability of distributed commissioning depended on the convergence of commissioners’ interests. Joint NHS and local government commissioning was more co-ordinated at strategic than operational level. NHS providers’ responsiveness to commissioners reflected how far their interests converged, but also providers’ own internal ability to implement agreements. Commissioning for mental health services and to prevent recurrent unplanned hospital readmissions relied more on local ‘micro-commissioning’ (collaborative care pathway design) than on competition. Service commissioning was irrelevant to intersectoral health promotion, but not clinical prevention work. On balance, the possibility of competition did not affect service outcomes in the ways that English NHS commissioning policies assumed. ‘Commodified’ planned orthopaedic surgery most lent itself to provider competition. In all three countries, tariff payments increased provider activity and commissioners’ costs. To contain costs, commissioners bundled tariff payments into blocks, agreed prospective case loads with providers and paid below-tariff rates for additional cases. Managerial performance, negotiated order and discursive control were the predominant media of power used by English, German and Italian commissioners. Conclusions Commissioning practice worked in certain respects differently from what NHS commissioning policy assumed. It was often laborious and uncertain. In the four English case study sites financial and ‘real-side’ contract negotiations were partly decoupled, clinician involvement being least on the financial side. Tariff systems weakened commissioners’ capacity to choose providers and control costs. Commissioners adapted the systems to solve this problem. Our findings suggest a need for further research into whether or not differently owned providers (corporate, third sector, public, professional partnership, etc.) respond differently to health-care commissioners and, if so, what specific implications for commissioning practice follow. They also suggest that further work is needed to assess how commissioning practices impact on health system integration when care pathways have to be constructed across multiple providers that must tender competitively for work, perhaps against each other. Funding The National Institute for Health Research Health Services and Delivery Research programme

Feeling our way: academia, emotions and a politics of care

This paper aims to better understand the role of emotions in academia, and their part in producing, and challenging, an increasingly normalized neoliberal academy. It unfolds from two narratives that foreground emotions in and across academic spaces and practices, to critically explore how knowledges and positions are constructed and circulated. It then moves to consider these issues through the lens of care as a political stance towards being and becoming academics in neoliberal times. Our aim is to contribute to the burgeoning literature on emotional geographies, explicitly bringing this work into conversation with resurgent debates surrounding an ethic of care, as part of a politic of critiquing individualism and managerialism in (and beyond) the academy. We consider the ways in which neoliberal university structures circulate particular affects, prompting emotions such as desire and anxiety, and the internalisation of competition and audit as embodied scholars. Our narratives exemplify how attendant emotions and affect can reverberate and be further reproduced through university cultures, and diffuse across personal and professional lives. We argue that emotions in academia matter, mutually co-producing everyday social relations and practices at and across all levels. We are interested in their political implications, and how neoliberal norms can be shifted through practices of caring-with

Chaotic mixing in noisy Hamiltonian systems

This paper summarises an investigation of the effects of low amplitude noise and periodic driving on phase space transport in 3-D Hamiltonian systems, a problem directly applicable to systems like galaxies, where such perturbations reflect internal irregularities and.or a surrounding environment. A new diagnsotic tool is exploited to quantify how, over long times, different segments of the same chaotic orbit can exhibit very different amounts of chaos. First passage time experiments are used to study how small perturbations of an individual orbit can dramatically accelerate phase space transport, allowing `sticky' chaotic orbits trapped near regular islands to become unstuck on suprisingly short time scales. Small perturbations are also studied in the context of orbit ensembles with the aim of understanding how such irregularities can increase the efficacy of chaotic mixing. For both noise and periodic driving, the effect of the perturbation scales roughly in amplitude. For white noise, the details are unimportant: additive and multiplicative noise tend to have similar effects and the presence or absence of a friction related to the noise by a Fluctuation- Dissipation Theorem is largely irrelevant. Allowing for coloured noise can significantly decrease the efficacy of the perturbation, but only when the autocorrelation time, which vanishes for white noise, becomes so large that t here is little power at frequencies comparable to the natural frequencies of the unperturbed orbit. This suggests strongly that noise-induced extrinsic diffusion, like modulational diffusion associated with periodic driving, is a resonance phenomenon. Potential implications for galaxies are discussed.Comment: 15 pages including 18 figures, uses MNRAS LaTeX macro