5,239 research outputs found
Kaon and Pion Fluctuations from Small Disoriented Chiral Condensates
Enhancement of omega and antiomega baryon production in Pb+Pb collisions at a
c.m. energy of 17 A GeV can be explained by the formation of many small
disoriented chiral condensate regions. This explanation implies that neutral
and charged kaons as well as pions must exhibit novel isospin fluctuations. We
compute the distribution of the fraction of neutral pions and kaons from such
regions. We then propose robust statistical observables that can be used to
extract the novel fluctuations from background contributions in pion and kaon
measurements at RHIC and LHC.Comment: 6 pages, revtex, 1 eps figur
Placement experience and learning motivations in Higher Education: a comparison between practical- and study-based programmes
Purpose - Placement-based learning is claimed to benefit educational outcomes in undergraduate programmes, with students gaining employability skills and the application of skill-sets in ‘real world’ situations. Most courses incorporate experiential learning; however, work placements remain exclusive to the aims of the academic programme. This report explores the changing learning motivations between students enrolled on: a) a practical-based programme, involving work placement (BA Adventure Education (Ad Ed)), and b) a study-based programme (BSc Sport and Exercise Science (SES)). In addition, motivation was examined between courses at each year. Design/methodology/approach - A 44 item Motivated Strategies for Learning Questionnaire was completed by first and final year undergraduates studying BA Ad Ed and BSc SES courses in the academic year 2011/12. Questionnaires were triangulated with focus groups, lecturer observations and statistical analyses. Findings - Learning motivation was influenced by: a) knowledge of academic grades, b) link between theoretical content and work experience, c) opportunity for reflection, and d) multidisciplinary nature of degree programmes. Furthermore, the majority of final year Ad Ed students showed understanding of the job market, degree transferability and career availability upon graduation. Originality/value - Where placement experience prepares British undergraduate learners for employment and provides insight into career demand, placements may also demotivate, particularly where careers do not necessitate degree qualification
The Milky Way Heart: Investigating molecular gas and gamma-ray morphologies in the Central Molecular Zone
Since the discovery of a broad distribution of very high energy (VHE; >0.1
TeV) gamma-rays in the Central Molecular Zone (CMZ) of the Galaxy in 2006 by
the HESS collaboration, the correlation of this emission with the integrated
intensity of the CS(1-0) molecular line emission has inferred a hadronic origin
for the gamma-rays. Here we describe the beginning of our investigation into
the strength of this correlation utilising new multi-line millimeter data from
the Mopra CMZ and HOP surveys and multi-wavelength GBT radio continuum
observations towards the CMZ and compare these in detail with the diffuse TeV
gamma-ray emission from HESS. The benefit of these new data is that they allow
us to simultaneously observe and analyse correlations using a large number
(>10) of molecular species, some of which contain their isotopologue pairs. The
use of isotopologue pairs is especially powerful, since it allows one to
analyse the optical depth of a number of different molecular species, thus
investigating the nature of the correlation over a range of different physical
conditions. Here we begin by comparing the integrated line emission and
continuum radio emission with the diffuse gamma-ray emission, and, by using
isotopologue pairs such as HCN/HCN, obtain optical depths throughout the
CMZ corresponding to regions of both strong and weak gamma-ray emission. We
find that the radio continuum better matches the peak of the gamma-ray
emission, which corresponds to the more compact -- compared to the relatively
coarse resolution of the gamma-ray images -- sources in the CMZ. Using the
isotopologue pairs, we find that the optical depth at all positions and
velocities within the CMZ are about 2--4. This is similar to that found for the
CS(1--0) line and would underestimate the mass of the CMZ, potentially
explaining why molecular line emission peaks appear offset from the gamma-ray
peaks.Comment: 8 pages, 5 figures. Accepted to the Proceedings of the 25th Texas
Symposium on Relativistic Astrophysics (Heidelberg, 2010
Regulation of protein kinase B and glycogen synthase kinase-3 by insulin and beta-adrenergic agonists in rat epididymal fat cells - Activation of protein kinase B by wortmannin-sensitive and -insensittve mechanisms
Previous studies using L6 myotubes have suggested that glycogen synthase kinase-3 (GSK-3) is phosphoryl ated and inactivated in response to insulin by protein kinase B (PKB, also known as Akt or RAG) (Cross, D, A, E., Alessi, D, R., Cohen, P., Andjelkovic, M., and Hemmings, B, A. (1995) Nature 378, 785-789), In the present study, marked increases in the activity of PKB have been shown to occur in insulin-treated rat epididymal fat cells with a time course compatible with the observed decrease in GSK-3 activity, Isoproterenol, acting primarily through beta(3)-adrenoreceptors, was found to decrease GSK-3 activity to a similar extent (approximately 50%) to insulin, However, unlike the effect of insulin, the inhibition of GSK by isoproterenol was not found to be sensitive to inhibition by the phosphatidylinositol 3'-kinase inhibitors, wortmannin or LY 294002, The change in GSK-3 activity brought about by isoproterenol could not be mimicked by the addition of permeant cyclic AMP analogues or forskolin to the cells, although at the concentrations used, these agents were able to stimulate lipolysis. Isoproterenol, but again not the cyclic AMP analogues, was found to increase the activity of PKB, although to a lesser extent than insulin. While wortmannin abolished the stimulation of PKB activity by insulin, it was without effect on the activation seen in response to isoproterenol, The activation of PKB by isoproterenol was not accompanied by any detectable change in the electrophoretic mobility of the protein on SDS-polyacrylamide gel electrophoresis. It would therefore appear that distinct mechanisms exist for the stimulation of PKB by insulin and isoproterenol in rat fat cells
The length of time's arrow
An unresolved problem in physics is how the thermodynamic arrow of time
arises from an underlying time reversible dynamics. We contribute to this issue
by developing a measure of time-symmetry breaking, and by using the work
fluctuation relations, we determine the time asymmetry of recent single
molecule RNA unfolding experiments. We define time asymmetry as the
Jensen-Shannon divergence between trajectory probability distributions of an
experiment and its time-reversed conjugate. Among other interesting properties,
the length of time's arrow bounds the average dissipation and determines the
difficulty of accurately estimating free energy differences in nonequilibrium
experiments
Who is in the transition gap? Transition from CAMHS to AMHS in the Republic of Ireland
Objective: The ITRACK study explored the process and predictors of transition between Child and Adolescent Mental Health Services (CAMHS) and Adult Mental Health Services (AMHS) in the Republic of Ireland. Method: Following ethical approval, clinicians in each of Ireland's four Health Service Executive (HSE) areas were contacted, informed about the study and invited to participate. Clinicians identified all cases who had reached the transition boundary (i.e. upper age limit for that CAMHS team ) between January and December 2010. Data were collected on clinical and socio-demographic details and factors that informed the decision to refer or not refer to AMHS and case notes were scrutinised to ascertain the extent of information exchanged between services during transition
CFD assessment of the effect of nanoparticles on the heat transfer properties of acetone/ZnBr2 solution
A potential novel working fluid for vapour absorption refrigeration utilising very low grade waste heat, is based on acetone and zinc bromide as the salt solution. A Computational Fluid Dynamics (CFD) model is presented of the fluid with zinc oxide nano-particles in a flat tube flow. A two phase type of model represents the zinc oxide nano-particles as a distinct fluid phase. The cases of laminar and turbulent flow are explored numerically for a wide range of acetone and nanoparticles concentrations. The velocity is varied between 1.5 and 6 ms−1, representing typical heat exchanger conditions. Reynolds number depends significantly on the solution concentration. Heat transfer coefficient increases with Re, by turbulent mixing, and with the concentration of nanoparticles and of acetone by the enhanced thermal diffusivity. The shear wall stress is not affected by changing the concentration of nano-particles. The nano-fluid is demonstrated to work well for heat transfer enhancement over the base fluid; the further issue of suspension of the nano-particles in the solution is explored experimentally. The nano-fluid can be achieved by ultra-sonic excitation, with a settling time in the order of several hours. Subject to the particle suspension time being increased, this fluid combination is a good candidate for the application considered
Jet substructure as a new Higgs search channel at the LHC
It is widely considered that, for Higgs boson searches at the Large Hadron
Collider, WH and ZH production where the Higgs boson decays to b anti-b are
poor search channels due to large backgrounds. We show that at high transverse
momenta, employing state-of-the-art jet reconstruction and decomposition
techniques, these processes can be recovered as promising search channels for
the standard model Higgs boson around 120 GeV in mass.Comment: 4 pages, 3 figure
Processes Contributing to the Maintenance of Flying Phobia: A Narrative Review
Flying phobia is a highly prevalent anxiety disorder, which causes sufferers significant distress and life interference. The processes which maintain flying phobia remain poorly understood. A systematic search of the literature was performed to identify what research has been conducted into the processes which may be involved in the fear of flying and whether processes which are believed to maintain other anxiety disorder diagnoses have been investigated in flying phobia. The results of the literature review are presented and related to existing cognitive behavioural theory and research. The results indicate that little research has been conducted into a number of areas considered important in the wider cognitive behavioural literature on anxiety disorders: namely attention, mental imagery, memory, worry and safety-seeking behaviours. The review proposes a hypothetical model, derived from cognitive behavioural theory, for the processes which may be involved in maintaining flying phobia, and considers a number of areas for future research
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