A spitzer survey of deep drilling fields to be targeted by the Vera C. Rubin observatory legacy survey of space and time

The Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) will observe several Deep Drilling Fields (DDFs) to a greater depth and with a more rapid cadence than the main survey. In this paper, we describe the 'DeepDrill' survey, which used the Spitzer Space Telescope Infrared Array Camera (IRAC) to observe three of the four currently defined DDFs in two bands, centred on 3.6 and 4.5 μm. These observations expand the area that was covered by an earlier set of observations in these three fields by the Spitzer Extragalactic Representative Volume Survey (SERVS). The combined DeepDrill and SERVS data cover the footprints of the LSST DDFs in the Extended Chandra Deep Field-South (ECDFS) field, the ELAIS-S1 field (ES1), and the XMM-Large-Scale Structure Survey field (XMM-LSS). The observations reach an approximate 5σ point-source depth of 2 μJy (corresponding to an AB magnitude of 23.1; sufficient to detect a 1011 M⊙ galaxy out to z ≈ 5) in each of the two bands over a total area of ≈ 29 deg2. The dual-band catalogues contain a total of 2.35 million sources

Delayed Enhancement Imaging: Standardized Segmental Assessment of Myocardial Viability in Patients with ST-Elevation Myocardial Infarction

Objective: To prospectively compare a selective short axis slice positioning method (selective 3-of-5) used in combination with a single long-axis slice, to the conventional short axis multi-slice technique in the assessment of myocardial viability. Materials and methods: Thirty-one patients with recent or chronic ST segment elevation myocardial infarct (STEMI) were recruited to undergo delayed enhancement (DE) cardiac magnetic resonance imaging (CMR). All patients underwent both methods of DE imaging, with subsequent review of both sets of data by two experienced observers. Sensitivity and specificity, as well as intra and interobserver reproducibility for both techniques were assessed. Results: There was good agreement between the selective 3-of-5 and the conventional multi-slice method for the assessment of viability, with no significant difference in results for sensitivity or reproducibility between the techniques. Conclusion: In patients with STEMI, a selective 3-of-5 short axis slice acquisition used in combination with a single vertical long-axis slice can be utilised to produce a standard American Heart Association (AHA) 17-segment model for the assessment of myocardial viability

Mutual passivation of group IV donors and isovalent nitrogen in diluted GaN{sub x}As{sub 1-x} alloys

We demonstrate the mutual passivation of electrically active group IV donors and isovalent N atoms in the GaN{sub x}As{sub 1-x} alloy system. This phenomenon occurs through the formation of a donor-nitrogen bond in the nearest neighbor IV{sub Ga}-N{sub As} pairs. In Si doped GaInN{sub 0.017}As{sub 0.983} the electron concentration starts to decrease rapidly at an annealing temperature of 700 C from {approx} 3 x 10{sup 19}cm{sup -3} in the as-grown state to less than 10{sup 16}cm{sup -3} after an annealing at 900 C for 10 s. At the same time annealing of this sample at 950 C increases the gap by about 35 meV, corresponding to a reduction of the concentration of the active N atoms by an amount very close to the total Si concentration. We also show that the formation of Si{sub Ga}-N{sub As} pairs is controlled by the diffusion of Si via Ga vacancies to the nearest N{sub As} site. The general nature of this mutual passivation effect is confirmed by our study of Ge doped GaN{sub x}As{sub 1-x} layers formed by N and Ge co-implantation in GaAs followed by pulsed laser melting