This paper, the first of two, introduces an observational study of spiral structure in galaxies chosen from the Spitzer Infrared Nearby Galaxies Survey (SINGS). Near‐infrared (NIR) and optical data are used to produce mass surface density maps, and from these the morphology of the disc is examined. The aim of this work is to characterize the prevalence of spiral structure in this sample and, in the cases where a clear spiral pattern is found, include the findings in a comparative study (reported in Paper II). A two‐armed (‘grand design’) spiral pattern is found in approximately half of the galaxies studied, including all those that are designated as grand design in the optical, but also including some, but not all, optically flocculent galaxies. It is found that the level of non‐axisymmetric structure in the galaxies’ mass distributions is only modestly higher in those galaxies that are classified as ‘grand design’ compared with those that are not, implying that non‐grand design galaxies possess significant power in higher order modes. There is no evidence that bars preferentially trigger the spirals, but they do appear to stir up non‐axisymmetric structure in the disc. In contrast, there is evidence that strong/close tidal interactions with companion galaxies are associated with strong two‐armed spiral structure in the IR, though there are a number of galaxies with relatively weak IR spiral structure that do not possess such companions.

Objectives: The coronavirus 2019 (COVID-19) pandemic has overwhelmed health care systems and disrupted routine care internationally. Health care workers face disruption to their work routines and professional development, as well as an elevated risk of infection and morbidity. We sought to establish the impact of the COVID-19 pandemic on the well-being, practice, and progression of all trainees in cardiothoracic surgery in the United Kingdom. Methods: A 31-item questionnaire was designed, validated, and disseminated via email and an instant-messaging platform. Results: In total, 76 (of 118, 64%) cardiothoracic surgical trainees responded, representing all training grades and programs nationally; 48 (63%) and 24 (32%) were concerned about their physical and mental health, respectively, 25 (33%) had taken time off work due to COVID-19, 65 (86%) had treated patients with COVID-19, 36 of whom (55%) were wearing satisfactory personal protective equipment at the time, 41 (54%) remain concerned about personal protective equipment provision at their institution, 42 (55%) had been redeployed to cover other specialties, and 23 (30%) had encountered ethical dilemmas related to care of patients. There was a significant impact on time spent in outpatient clinics (44% reduction), multidisciplinary team meetings (79% reduction), and operating theaters (78% reduction). In total, 67 (88%) of respondents were concerned about the impact on their training, and 54 (71%) felt that the deviation may require an extension in their planned training time. Conclusions: The duration and impact of the current pandemic is, as yet, uncertain. Timely sharing of experiences, concerns, and expectations will inform health care and education policy and influence practice in the pandemic era and beyond. (J

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We use SPITZER IRAC 3.6 and 4.5micron near infrared data from the Spitzer Infrared Nearby Galaxies Survey (SINGS), optical B, V and I and 2MASS Ks band data to produce mass surface density maps of M81. The IRAC 3.6 and 4.5micron data, whilst dominated by emission from old stellar populations, is corrected for small-scale contamination by young stars and PAH emission. The I band data are used to produce a mass surface density map by a B-V colour-correction, following the method of Bell and de Jong. We fit a bulge and exponential disc to each mass map, and subtract these components to reveal the non-axisymmetric mass surface density. From the residual mass maps we are able to extract the amplitude and phase of the density wave, using azimuthal profiles. The response of the gas is observed via dust emission in the 8micron IRAC band, allowing a comparison between the phase of the stellar density wave and gas shock. The relationship between this angular offset and radius suggests that the spiral structure is reasonably long lived and allows the position of corotation to be determined.Comment: 15 pages, 17 figures, accepted for publication in MNRA