1,268 research outputs found

    Carbon radio recombination lines from gigahertz to megahertz frequencies towards Orion A

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    Context. The combined use of carbon radio recombination lines (CRRLs) and the 158 μ\mum-[CII] line is a powerful tool for the study of the energetics and physical conditions (e.g., temperature and density) of photodissociation regions (PDRs). However, there are few observational studies that exploit this synergy. Aims. Here we explore the relation between CRRLs and the 158 μ\mum-[CII] line in light of new observations and models. Methods. We present new and existing observations of CRRLs in the frequency range 0.15--230 GHz with ALMA, VLA, the GBT, Effelsberg 100m, and LOFAR towards Orion~A (M42). We complement these observations with SOFIA observations of the 158 μ\mum-[CII] line. We studied two PDRs: the foreground atomic gas, known as the Veil, and the dense PDR between the HII region and the background molecular cloud. Results. In the Veil we are able to determine the gas temperature and electron density, which we use to measure the ionization parameter and the photoelectric heating efficiency. In the dense PDR, we are able to identify a layered PDR structure at the surface of the molecular cloud to the south of the Trapezium cluster. There we find that the radio lines trace the colder portion of the ionized carbon layer, the C+^{+}/C/CO interface. By modeling the emission of the 158158~μ\mum-[CII] line and CRRLs as arising from a PDR we derive a thermal pressure >5×107>5\times10^{7} K cm−3^{-3} and a radiation field G0≈105G_{0}\approx10^{5} close to the Trapezium. Conclusions. This work provides additional observational support for the use of CRRLs and the 158 μ\mum-[CII] line as complementary tools to study dense and diffuse PDRs, and highlights the usefulness of CRRLs as probes of the C+^{+}/C/CO interface.Comment: 18 pages, 16 figures, accepted for publication in A&

    Post-discharge Telemonitoring of Physical Activity, Vital Signs, and Patient-Reported Symptoms in Older Patients Undergoing Cancer Surgery

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    BACKGROUND: Postoperative home monitoring could potentially detect complications early, but evidence in oncogeriatric surgery is scarce. Therefore, we evaluated whether post-discharge physical activity, vital signs, and patient-reported symptoms are related to post-discharge complications and hospital readmissions in older patients undergoing cancer surgery. METHODS: In this observational cohort study, we monitored older patients (≥65 years of age) undergoing cancer surgery, for 2 weeks post-discharge using tablet-based applications and connected devices. Outcome measures were post-discharge complications and readmissions; physical activity and patient-reported symptoms over time; and threshold violations for physical activity (step count 38°C; blood pressure 150/100 mmHg; heart rate 100 bpm; weight -5% or +5% of weight at discharge); and patient-reported symptoms (pain score greater than the previous day; presence of dyspnea, vomiting, dizziness, fever). RESULTS: Of 58 patients (mean age 72 years), 24 developed a post-discharge complication and 13 were readmitted. Measured parameters indicated 392 threshold violations out of 5379 measurements (7.3%) in 40 patients, mostly because of physical inactivity. Patients with readmissions had lower physical activity at discharge and at day 9 after discharge and violated a physical activity threshold more often. Patients with post-discharge complications had a higher median pain score compared with patients without these adverse events. No differences in threshold violations of other parameters were observed between patients with and without post-discharge complications and readmissions. CONCLUSION: Our results show the potential of telemonitoring older patients after cancer surgery but confirm that detecting post-discharge complications is complex and multifactorial

    Perioperative telemonitoring of older adults with cancer:Can we connect them all?

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    OBJECTIVES: Although the increasing cancer incidence in older patients is widely recognised, older patients remain underrepresented in clinical cancer trials and eHealth studies. The aim of this research is to identify technological and patient-related barriers to inclusion of this population in a clinical eHealth study. MATERIAL AND METHODS: This is a retrospective analysis of a prospective cohort study with older patients (≥ 65 years) undergoing cancer-related surgery, who were identified for a perioperative telemonitoring study. Reasons for ineligibility and refusal had been prospectively registered. Characteristics and postoperative outcomes were compared between participants and non-participants. RESULTS: Between May 2018 and March 2020, 151 patients were assessed for eligibility, resulting in 65 participants and 86 non-participants. The main reason for ineligibility was lack of internet access at home (n = 16), while main reasons for refusal were perceived high mental burden (n = 46) and insufficient digital skills (n = 12). Compared with participants, non-participants were significantly older (mean age 75 vs. 73, p = 0.01); more often female (64% vs. 35%, p = 0.00), unmarried (42% vs. 8%, p = 0.01) living alone (38% vs. 19%, p = 0.02); had a higher ASA classification (43% vs. 19%, p = 0.00); often had polypharmacy (67% vs. 43%, p = 0.00); and were more often discharged to skilled nursing facilities (0% vs. 15%, p = 0.00). CONCLUSION: Our results confirm the underrepresentation of older female patients with little support from a partner and higher comorbidity. We should be aware of technological and patient-related barriers to including older adults with cancer, in order to avoid further dividing patients with low and high digital health literacy

    An Automated Scalable Framework for Distributing Radio Astronomy Processing Across Clusters and Clouds

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    The Low Frequency Array (LOFAR) radio telescope is an international aperture synthesis radio telescope used to study the Universe at low frequencies. One of the goals of the LOFAR telescope is to conduct deep wide-field surveys. Here we will discuss a framework for the processing of the LOFAR Two Meter Sky Survey (LoTSS). This survey will produce close to 50 PB of data within five years. These data rates require processing at locations with high-speed access to the archived data. To complete the LoTSS project, the processing software needs to be made portable and moved to clusters with a high bandwidth connection to the data archive. This work presents a framework that makes the LOFAR software portable, and is used to scale out LOFAR data reduction. Previous work was successful in pre-processing LOFAR data on a cluster of isolated nodes. This framework builds upon it and and is currently operational. It is designed to be portable, scalable, automated and general. This paper describes its design and high level operation and the initial results processing LoTSS data

    The discovery of diffuse steep spectrum sources in Abell 2256

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    Context: Hierarchical galaxy formation models indicate that during their lifetime galaxy clusters undergo several mergers. Here we report on the discovery of three diffuse radio sources in the periphery of Abell 2256, using the GMRT. Aims: The aim of the observations was to search for diffuse ultra-steep spectrum radio sources within the galaxy cluster Abell 2256. Methods: We have carried out GMRT 325 MHz radio continuum observations of Abell 2256. V, R and I band images of the cluster were taken with the 4.2m WHT. Results: We have discovered three diffuse elongated radio sources located about 1 Mpc from the cluster center. Two are located to the west of the cluster center, and one to the southeast. The sources have a measured physical extent of 170, 140 and 240 kpc, respectively. The two western sources are also visible in deep low-resolution 115-165 MHz WSRT images, although they are blended into a single source. For the combined emission of the blended source we find an extreme spectral index of -2.05\pm 0.14 between 140 and 351 MHz. The extremely steep spectral index suggests these two sources are most likely the result of adiabatic compression of fossil radio plasma due to merger shocks. Conclusions: The discovery of the steep spectrum sources implies the existence of a population of faint diffuse radio sources in (merging) clusters with such steep spectra that they have gone unnoticed in higher frequency (\gtrsim 1 GHz) observations. An exciting possibility therefore is that such sources will determine the general appearance of clusters in low-frequency high resolution radio maps as will be produced by for example LOFAR or LWA.Comment: 5 pages, 2 figures, accepted for publication in A&A on October 16, 200
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