RDWIA analysis of 12C(e,e'p) for Q^2 < 2 (GeV/c)^2

We analyze data for 12C(e,e'p) with Q^2 < 2 (GeV/c)^2 using the relativistic distorted-wave impulse approximation (RDWIA) based upon Dirac-Hartree wave functions. The 1p normalization extracted from data for Q^2 > 0.6 (GeV/c)^2 is approximately 0.87, independent of Q^2, which is consistent with the predicted depletion by short-range correlations. The total 1p and 1s strength for E_m < 80 MeV approaches 100% of IPSM, consistent with a continuum contribution for 30 < E_m < 80 MeV of about 12% of IPSM. Similarly, a scale factor of 1.12 brings RDWIA calculations into good agreement with 12C(e,e'p) data for transparency. We also analyzed low Q^2 data from which a recent NDWIA analysis suggested that spectroscopic factors might depend strongly upon the resolution of the probe. We find that momentum distributions for their empirical Woods-Saxon wave functions fit to low Q^2 data for parallel kinematics are too narrow to reproduce data for quasiperpendicular kinematics, especially for larger Q^2, and are partly responsible for reducing fitted normalization factors.Comment: 19 pages, 14 figures, to be submitted to PR

Performance analysis of air source heat pumps using detailed simulations and comparison to field trial data

The take-up of heat pump technologies in the UK domestic sector has lagged far behind other countries in Europe and North America due primarily to the ready availability of cheap natural gas; this has led to the predominance of gas central heating systems in UK housing. However, with recent gas price volatility along with the depletion of the UK's natural gas reserves interest in heat pump technology, particularly Air source heat pumps (ASHPs) is growing as they have the potential to be a direct, low-carbon replacement for existing gas boiler systems. However, to-date there have been few detailed, simulation-based performance studies of ASHP systems. In this paper a robust, dynamic simulation model of an ASHP device is described. The ASHP model has been integrated into a whole-building model and used to analyse the performance of a retro-fit domestic ASHP heating system. The simulation results were then compared to field trial data

Test of Fermi Gas Model and Plane-Wave Impulse Approximation Against Electron-Nucleus Scattering Data

A widely used relativistic Fermi gas model and plane-wave impulse approximation are tested against electron-nucleus scattering data. Inclusive quasi-elastic cross section are calculated and compared with high-precision data for C, O, and Ca. A dependence of agreement between calculated cross section and data on a momentum transfer is shown. Results for the C(nu_mu,mu) reaction are presented and compared with experimental data of the LSND collaboration.Comment: 10 pages, 8 figure

In-trail dynamics of multiple CDTI-equipped aircraft queues

One of the potential problems of in-trail self-spacing with a Cockpit Display of Traffic Information (CDTI) is whether dynamic oscillations would occur in a queue of aircraft flying an approach, similar to the ""accordion'' effect seem with the queue of automobiles in stop-and-go traffic. In order to gain some insight into this potential problem, a brief experiment was conducted with the Transport Systems Research Vehicle (TSRV) ground-based simulator equipped with CDTI which presented the position of other aircraft in the area. Three simulation sessions were conducted wherein queues of up to nine aircraft were built, each one self-spacing on the preceding aircraft. The aircraft crews were rotated to ensure that the pilots had no prior knowledge of the lead aircraft behavior they would be following. Two different spacing criteria were employed: a constant time predictor criterion and a constant time delay criterion. The experiment failed to uncover any dynamic oscillatory tendencies in queues of seven to nine aircraft

Electronic structure induced reconstruction and magnetic ordering at the LaAlO3∣_3|SrTiO3_3 interface

Using local density approximation (LDA) calculations we predict GdFeO$_3$-like rotation of TiO$_6$ octahedra at the $n$-type interface between LaAlO$_3$ and SrTiO$_3$. The narrowing of the Ti $d$ bandwidth which results means that for very modest values of $U$, LDA$+U$ calculations predict charge and spin ordering at the interface. Recent experimental evidence for magnetic interface ordering may be understood in terms of the close proximity of an antiferromagnetic insulating ground state to a ferromagnetic metallic excited state

Quasi-elastic neutrino charged-current scattering cross sections on oxygen

The charged-current quasi-elastic scattering of muon neutrinos on oxygen target is computed for neutrino energies between 200 MeV and 2.5 GeV using the relativistic distorted-wave impulse approximation with relativistic optical potential, which was earlier successfully applied to describe electron-nucleus data. We study both neutrino and electron processes and show that the reduced exclusive cross sections for neutrino and electron scattering are similar. The comparison with the relativistic Fermi gas model (RFGM), which is widely used in data analyses of neutrino experiments, shows that the RFGM fails completely when applied to exclusive cross section data and leads to overestimated values of inclusive and total cross sections. We also found significant nuclear-model dependence of exclusive, inclusive and total cross sections for about 1 GeV energy.Comment: 30 pages, 11 figures; final version to appear in Phys. Rev.

The Infrared Nucleus of the Wolf-Rayet Galaxy Henize 2-10

We have obtained near-infrared images and mid-infrared spectra of the starburst core of the dwarf Wolf-Rayet galaxy He 2-10. We find that the infrared continuum and emission lines are concentrated in a flattened ellipse 3-4'' or 150 pc across which may show where a recent accretion event has triggered intense star formation. The ionizing radiation from this cluster has an effective temperature of 40,000 K, corresponding to $30M_\odot$ stars, and the starburst is $0.5-1.5 \times 10^7$ years old.Comment: 17 pages Latex, 7 postscript figures, 1 postscript table, accepted to A

Identifying studies for systematic reviews - An example from medical imaging

Objectives: To determine if published figures on the proportion of articles included in systematic reviews and identified in electronic databases are applicable to an example from medical imaging. Methods: A systematic review was performed. Additionally, sensitivity and precision of a MEDLINE search were compared with values from three published searches, each customized for a specific field. Results: All articles included in the systematic review were in electronic databases. The MEDLINE search had low precision compared with searches in other fields. Conclusions: in a specific area of medical imaging, electronic databases, including MEDLINE, are reliable sources of articles

Mapping CS in Starburst Galaxies: Disentangling and Characterising Dense Gas

Aims. We observe the dense gas tracer CS in two nearby starburst galaxies to determine how the conditions of the dense gas varies across the circumnuclear regions in starburst galaxies. Methods. Using the IRAM-30m telescope, we mapped the distribution of the CS(2-1) and CS(3-2) lines in the circumnuclear regions of the nearby starburst galaxies NGC 3079 and NGC 6946. We also detected the formaldehyde (H2CO) and methanol (CH3OH) in both galaxies. We marginally detect the isotopologue C34S. Results. We calculate column densities under LTE conditions for CS and CH3OH. Using the detections accumulated here to guide our inputs, we link a time and depth dependent chemical model with a molecular line radiative transfer model; we reproduce the observations, showing how conditions where CS is present are likely to vary away from the galactic centres. Conclusions. Using the rotational diagram method for CH3OH, we obtain a lower limit temperature of 14 K. In addition to this, by comparing the chemical and radiative transfer models to observations, we determine the properties of the dense gas as traced by CS (and CH3OH). We also estimate the quantity of the dense gas. We find that, provided that there are a between 10^5 and 10^6 dense cores in our beam, for both target galaxies, emission of CS from warm (T = 100 - 400 K), dense (n(H2) = 10^5-6 cm-3) cores, possibly with a high cosmic ray ionisation rate (zeta = 100 zeta0) best describes conditions for our central pointing. In NGC 6946, conditions are generally cooler and/or less dense further from the centre, whereas in NGC 3079, conditions are more uniform. The inclusion of shocks allows for more efficient CS formation, leading to an order of magnitude less dense gas being required to replicate observations in some cases.Comment: 14 pages, 10 figures, accepted to A&