Two-colour QCD at non-zero quark-number density

We have simulated two-colour four-flavour QCD at non-zero chemical potential $\mu$ for quark number. Simulations were performed on $8^4$ and $12^3 \times 24$ lattices. Clear evidence was seen for the formation of a colourless diquark condensate which breaks quark number spontaneously, for $\mu > \mu_c \sim m_\pi/2$. The transition appears to be second order. We have measured the spectrum of scalar and pseudoscalar bosons which shows clear evidence for the expected Goldstone boson. Our results are in qualitative agreement with those from effective Lagrangians for the potential Goldstone excitations of this theory.Comment: 22 pages RevTeX, 6 figures in 10 postscript file

Effect of pressure on the crystal structure of L-serine-I and the crystal structure of L-serine-II at 5.4 GPa

The crystal structure of L-serine has been determined at room temperature at pressures between 0.3 and 4.8 GPa. The structure of this phase ( hereafter termed L-serine-I), which consists of the molecules in their zwitterionic tautomer, is orthorhombic, space group P2(1)2(1)2(1). The least compressible cell dimension (c), corresponds to chains of head-to-tail NH ... carboxylate hydrogen bonds. The most compressible direction is along b, and the pressure-induced distortion in this direction takes the form of closing up voids in the middle of R-type hydrogen-bonded ring motifs. This occurs by a change in the geometry of hydrogen-bonded chains connecting the hydroxyl groups of the - CH2OH side chains. These hydrogen bonds are the longest conventional hydrogen bonds in the system at ambient pressure, having an O ... O separation of 2.918 (4) Angstrom and an O ... O ... O angle of 148.5 (2)degrees; at 4.8 GPa these parameters are 2.781 (11) and 158.5 (7) degrees. Elsewhere in the structure one NH ... O interaction reaches an N ... O separation of 2.691 (13) Angstrom at 4.8 GPa. This is amongst the shortest of this type of interaction to have been observed in an amino acid crystal structure. Above 4.8 GPa the structure undergoes a single-crystal-to-single-crystal phase transition to a hitherto uncharacterized polymorph, which we designate L-serine-II. The OH ... OH hydrogen-bonded chains of L-serine-I are replaced in L-serine-II by shorter OH ... carboxyl interactions, which have an O ... O separation of 2.62 (2) Angstrom. This phase transition occurs via a change from a gauche to an anti conformation of the OH group, and a change in the NCalphaCO torsion angle from -178.1 (2)degrees at 4.8 GPa to -156.3 (10)degrees at 5.4 GPa. Thus, the same topology appears in both crystal forms, which explains why it occurs from one single- crystal form to another. The transition to L-serine-II is also characterized by the closing-up of voids which occur in the centres of other R-type motifs elsewhere in the structure. There is a marked increase in CH ... O hydrogen bonding in both phases relative to L-serine-I at ambient pressure.</p

Bringing remote sensing technology to the user community

The procedures and services available for educating and training potential users of remote sensing technology are discussed along with approaches for achieving an in-house capability for the analysis of remotely sensed data using numerical techniques based on pattern recognition principles. Cost estimates are provided where appropriate

Systematically searching for and assessing the literature for self-management of chronic pain: A lay users' perspective

© 2014 Schofield et al.; licensee BioMed Central Ltd. Background: The Engaging with older adults in the development of strategies for the self management of chronic pain (EOPIC) study aims to design and develop self management strategies to enable older adults to manage their own pain. Involving older adults in research into chronic pain management will better enable the identification and development of strategies that are more appropriate for their use, but how can perspectives really be utilised to the best possible outcomes?. Method. Seven older adults were recruited through a local advertising campaign to take part. We also invited participants from the local pain services, individuals who had been involved in earlier phase of the EOPIC study and a previous ESRC funded project. The group undertook library training and research skills training to facilitate searching of the literature and identified sources of material. A grading tool was developed using perceived essential criteria identified by the older adults and material was graded according to the criteria within this scale. Results: Fifty-seven resources from over twenty-eight sources were identified. These materials were identified as being easily accessible, readable and relevant. Many of the web based materials were not always easy to find or readily available so they were excluded by the participants. All but one were UK based. Forty-four items were identified as meeting the key criteria for inclusion in the study. This included five key categories as follows; books, internet, magazines, leaflets, CD's/Tapes. Conclusion: This project was able to identify a number of exemplars of self management material along with some general rules regarding the categories identified. We must point out that the materials identified were not age specific, were often locally developed and would need to be adapted to older adults with chronic pain. For copyright issues we have not included them in this paper. The key message is really related to the format rather than the content. However, the group acknowledge that these may vary according to the requirements of each individual older adult and therefore recommend the development of a leaflet to help others in their search for resources. This leaflet has been developed as part of Phase IV of the EOPIC study

Ultraviolet to infrared emission of z>1 galaxies: Can we derive reliable star formation rates and stellar masses?

We seek to derive star formation rates (SFR) and stellar masses (M_star) in distant galaxies and to quantify the main uncertainties affecting their measurement. We explore the impact of the assumptions made in their derivation with standard calibrations or through a fitting process, as well as the impact of the available data, focusing on the role of IR emission originating from dust. We build a sample of galaxies with z>1, all observed from the UV to the IR (rest frame). The data are fitted with the code CIGALE, which is also used to build and analyse a catalogue of mock galaxies. Models with different SFHs are introduced. We define different set of data, with or without a good sampling of the UV range, NIR, and thermal IR data. The impact of these different cases on the determination of M_star and SFR are analysed. Exponentially decreasing models with a redshift formation of the stellar population z ~8 cannot fit the data correctly. The other models fit the data correctly at the price of unrealistically young ages when the age of the single stellar population is taken to be a free parameter. The best fits are obtained with two stellar populations. As long as one measurement of the dust emission continuum is available, SFR are robustly estimated whatever the chosen model is, including standard recipes. M_star measurement is more subject to uncertainty, depending on the chosen model and the presence of NIR data, with an impact on the SFR-M_star scatter plot. Conversely, when thermal IR data from dust emission are missing, the uncertainty on SFR measurements largely exceeds that of stellar mass. Among all physical properties investigated here, the stellar ages are found to be the most difficult to constrain and this uncertainty acts as a second parameter in SFR measurements and as the most important parameter for M_star measurements.Comment: 14 pages, 14 figures, accepted for publication A&

Mesons and Flavor on the Conifold

We explore the addition of fundamental matter to the Klebanov-Witten field theory. We add probe D7-branes to the ${\cal N}=1$ theory obtained from placing D3-branes at the tip of the conifold and compute the meson spectrum for the scalar mesons. In the UV limit of massless quarks we find the exact dimensions of the associated operators, which exhibit a simple scaling in the large-charge limit. For the case of massive quarks we compute the spectrum of scalar mesons numerically.Comment: 19 pages, 3 figures, v2: typos fixe

Making postgraduate students and supervisors aware of the role of emotions in the PhD process

Emotions are an integral part of the PhD process. A range of emotions are common and to be expected. How do emotions affect the PhD process for both postgraduate students and their supervisors? How can we make our emotions work positively for us in the PhD process? To explore answers to these questions, three lecturers currently supervising postgraduates and three postgraduates at various stages in their doctoral studies collectively pooled their experiences. We developed an interactive workshop that was recently conducted for postgraduate students at Murdoch University and at the Australian Association for Social Research annual conference 2002. This presentation will explore the role that emotions play in the PhD process and how supervisors and postgraduates alike can benefit from reflecting on this issue. A number of practical (and humorous) tips will be provided as well as examples from others' PhD experiences. The role of emotions at the beginning, middle and end of a PhD program will be explored. The data collection and analysis phases are a time when emotions may run riot. Trepidation is especially common when fieldwork or data collection is involved, as is anger when postgraduate's views about how the world works are challenged and then sadness (and relief!) when the data collection phase is finished. We will discuss how supervisors can assist their postgraduates to make these feelings work for them. The presentation will also explore the emotions that arise from the supervisor-postgraduate partnership