Pressure of Hot QCD at Large N_f

We compute the pressure and entropy of hot QCD in the limit of large number of fermions, N_f >> N_c ~ 1, to next to leading order in N_f. At this order the calculation can be done exactly, up to ambiguities due to the presence of a Landau pole in the theory; the ambiguities are O(T^8/\Lambda^4_{Landau}) and remain negligible long after the perturbative series (in g^2 N_f) has broken down. Our results can be used to test several proposed resummation schemes for the pressure of full QCD.Comment: 16 pages including 4 figures. Short enough for you to read. Numerical results corrected after an error was found by Andreas Ipp and Anton Rebha

Ulnar Collateral Ligament Reconstruction with Traditional Docking Compared to Novel Surgical Techniques

Background: Ulnar Collateral Ligament Reconstruction (UCLR) is a surgical procedure on one of the main ligaments that provides normal stability for the elbow joint against excessive valgus stress. Damage to this ligament is common in athletes performing overhead throwing activities, primarily baseball players, due to excessive valgus stress during the throwing motion. The most common form of treatment for this type of injury is reconstructive surgery of the ligament, especially if athletes wish to return to sport participation. This type of surgery is extremely invasive and requires extensive post-operative rehabilitation in order to facilitate return to play. To date, many surgical techniques have been proposed and evaluated, but there are no conclusive comparison studies on patient outcomes following UCLR. Purpose: The purpose of this paper is to analyze previous studies on UCLR techniques and determine if there is a single superior surgical method leading to improved biomechanical outcomes and decreased failure measures. Our focused clinical question was identifying if the traditional docking technique compared to novel docking techniques during UCLR superior in relation to biomechanical outcomes and failure measures in cadaveric tissue. Methodology: The study design in this paper is a critically appraised topic. Various scholarly databases such as PubMed, MEDLINE and SportDiscus were utilized to search for studies related to UCLR surgical techniques. After an initial search, a list of fifteen relevant studies were identified. Each study was then scrutinized and evaluated to meet predetermined inclusion criteria and a minimum score of 6/9 on the PEDro scale. All studies not meeting these requirements were excluded. This left a total of five articles which were then used to answer the clinical question for this paper. The inclusion criteria involved meeting a cadaveric age of 16-60 y, objective measures of valgus testing, angular displacement, stiffness and modes of failure as post-operative outcomes. Further, we included studies that had a minimum of seven cadaver pairs tested, and studies were required to compare traditional docking to at least one novel technique. Results: All five studies involved compared at least one novel surgical technique to the docking technique. Four studies found no significant overall difference between the native and reconstructed states of any surgical technique. One study found no overall significant difference, but did identify slight differences in biomechanical properties. Discussion: All conclusions from individual studies demonstrate comparable findings between all UCLR techniques. Biomechanics, kinematics and failure modes in the acute stages following surgery in cadavers are similar between UCLR techniques. Despite all that has been done, additional research is still necessary to determine a superior surgical technique

Determination of the critical current density in the d-wave superconductor YBCO under applied magnetic fields by nodal tunneling

We have studied nodal tunneling into YBa2Cu3O7-x (YBCO) films under magnetic fields. The films' orientation was such that the CuO2 planes were perpendicular to the surface with the a and b axis at 450 form the normal. The magnetic field was applied parallel to the surface and perpendicular to the CuO2 planes. The Zero Bias Conductance Peak (ZBCP) characteristic of nodal tunneling splits under the effect of surface currents produced by the applied fields. Measuring this splitting under different field conditions, zero field cooled and field cooled, reveals that these currents have different origins. By comparing the field cooled ZBCP splitting to that taken in decreasing fields we deduce a value of the Bean critical current superfluid velocity, and calculate a Bean critical current density of up to 3*10^7 A/cm2 at low temperatures. This tunneling method for the determination of critical currents under magnetic fields has serious advantages over the conventional one, as it avoids having to make high current contacts to the sample.Comment: 8 pages, 2 figure

Water Demand Management in England and Wales: constructions of the domestic water-user

YesMeasures to manage demand include implicit and explicit messages about domestic water-users which have important potential impacts on their perceptions and practices. Drawing on recent literature, this paper identifies three different ¿dimensions¿ along which demand management measures¿ constructions of the water-user may vary: these relate to whether the water user is passive or active, whether they are motivated by individual or common needs, and whether they perceive water as a right or a commodity. Demand management measures currently used in England and Wales are then discussed and analysed. The paper concludes by highlighting the importance of communications associated with demand management, and in particular, notes the need to consider the cumulative impact of messages and their interactions with people¿s existing understandings

Photometry of supernovae in an image series : methods and application to the Supernova Legacy Survey (SNLS)

We present a technique to measure lightcurves of time-variable point sources on a spatially structured background from imaging data. The technique was developed to measure light curves of SNLS supernovae in order to infer their distances. This photometry technique performs simultaneous PSF photometry at the same sky position on an image series. We describe two implementations of the method: one that resamples images before measuring fluxes, and one which does not. In both instances, we sketch the key algorithms involved and present the validation using semi-artificial sources introduced in real images in order to assess the accuracy of the supernova flux measurements relative to that of surrounding stars. We describe the methods required to anchor these PSF fluxes to calibrated aperture catalogs, in order to derive SN magnitudes. We find a marginally significant bias of 2 mmag of the after-resampling method, and no bias at the mmag accuracy for the non-resampling method. Given surrounding star magnitudes, we determine the systematic uncertainty of SN magnitudes to be less than 1.5 mmag, which represents about one third of the current photometric calibration uncertainty affecting SN measurements. The SN photometry delivers several by-products: bright star PSF flux mea- surements which have a repeatability of about 0.6%, as for aperture measurements; we measure relative astrometric positions with a noise floor of 2.4 mas for a single-image bright star measurement; we show that in all bands of the MegaCam instrument, stars exhibit a profile linearly broadening with flux by about 0.5% over the whole brightness range.Comment: Accepted for publication in A&A. 20 page

Comment on and Erratum to "Pressure of Hot QCD at Large N_f"

We repeat and correct the recent calculation of the thermodynamic potential of hot QCD in the limit of large number N_f of fermions. The new result for the thermal pressure turns out to agree significantly better with results obtained from perturbation theory at small coupling. For large coupling, a nonmonotonic behaviour is reproduced, but the pressure of the strongly coupled theory does not exceed the free pressure as long as the Landau pole ambiguity remains negligible numerically.Comment: 9 pages, 3 figures, JHEP3; v2: version accepted for publication in JHEP (title changed, 1 footnote added, 1 reference updated, content otherwise unchanged

Diffuse retro-reflective imaging for improved mosquito tracking around human baited bednets

Robust imaging techniques for tracking insects have been essential tools in numerous laboratory and field studies on pests, beneficial insects and model systems. Recent innovations in optical imaging systems and associated signal processing have enabled detailed characterisation of nocturnal mosquito behaviour around bednets and improvements in bednet design, a global essential for protecting populations against malaria. Nonetheless, there remain challenges around ease of use for large scale in situ recordings and extracting data reliably in the critical areas of the bednet where the optical signal is attenuated. Here we introduce a retro-reflective screen at the back of the measurement volume, which can simultaneously provide diffuse illumination, and remove optical alignment issues whilst requiring only one-sided access to the measurement space. The illumination becomes significantly more uniform, although, noise removal algorithms are needed to reduce the effects of shot noise particularly across low intensity bednet regions. By systematically introducing mosquitoes in front and behind the bednet in lab experiments we are able to demonstrate robust tracking in these challenging areas. Overall, the retro-reflective imaging setup delivers mosquito segmentation rates in excess of 90% compared to less than 70% with back-lit systems