791 research outputs found

    Diffraction-limited Subaru imaging of M82: sharp mid-infrared view of the starburst core

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    We present new imaging at 12.81 and 11.7 microns of the central ~40"x30" (~0.7x0.5 kpc) of the starburst galaxy M82. The observations were carried out with the COMICS mid-infrared (mid-IR) imager on the 8.2m Subaru telescope, and are diffraction-limited at an angular resolution of <0".4. The images show extensive diffuse structures, including a 7"-long linear chimney-like feature and another resembling the edges of a ruptured bubble. This is the clearest view to date of the base of the kpc-scale dusty wind known in this galaxy. These structures do not extrapolate to a single central point, implying multiple ejection sites for the dust. In general, the distribution of dust probed in the mid-IR anticorrelates with the locations of massive star clusters that appear in the near-infrared. The 10-21 micron mid-IR emission, spatially-integrated over the field of view, may be represented by hot dust with temperature of ~160 K. Most discrete sources are found to have extended morphologies. Several radio HII regions are identified for the first time in the mid-IR. The only potential radio supernova remnant to have a mid-IR counterpart is a source which has previously also been suggested to be a weak active galactic nucleus. This source has an X-ray counterpart in Chandra data which appears prominently above 3 keV and is best described as a hot (~2.6 keV) absorbed thermal plasma with a 6.7 keV Fe K emission line, in addition to a weaker and cooler thermal component. The mid-IR detection is consistent with the presence of strong [NeII]12.81um line emission. The broad-band source properties are complex, but the X-ray spectra do not support the active galactic nucleus hypothesis. We discuss possible interpretations regarding the nature of this source.Comment: Accepted for publication in PASJ Subaru special issue. High resolution version available temporarily at http://www.astro.isas.jaxa.jp/~pgandhi/pgandhi_m82.pd

    Reducing the psychosocial impact of aphasia on mood and quality of life in people with aphasia and the impact of caregiving in family members through the Aphasia Action Success Knowledge (Aphasia ASK) program: Study protocol for a randomized controlled trial

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    © 2016 Worrall et al. Background: People with aphasia and their family members are at high risk of experiencing post stroke depression. The impact of early interventions on mood and quality of life for people with aphasia is unknown. Methods/design: This study will determine whether an early intervention for both the person with aphasia after stroke and their family members leads to better mood and quality of life outcomes for people with aphasia, and less caregiver burden and better mental health for their family members. This is a multicenter, cluster-randomized controlled trial. Clusters, which are represented by Health Service Districts, will be randomized to the experimental intervention (Aphasia Action Success Knowledge Program) or an attention control (Secondary Stroke Prevention Information Program). People with aphasia and their family members will be blinded to the study design and treatment allocation (that is, will not know there are two arms to the study). Both arms of the study will receive usual care in addition to either the experimental or the attention control intervention. A total of 344 people with aphasia and their family members will be recruited. Considering a cluster size of 20, the required sample size can be achieved from 18 clusters. However, 20 clusters will be recruited to account for the potential of cluster attrition during the study. Primary outcome measures will be mood and quality of life of people with aphasia at 12 months post stroke. Secondary measures will be family member outcomes assessing the impact of caregiving and mental health, and self-reported stroke risk-related behaviors of people with aphasia. Discussion: This is the first known program tailored for people with aphasia and their family members that aims to prevent depression in people with aphasia by providing intervention early after the stroke. Trial registration: This trial is registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) as ACTRN12614000979651. Date registered: 11 September 2014

    The Chandra X-ray Observatory Resolves the X-ray Morphology and Spectra of a Jet in PKS 0637-752

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    The core-dominated radio-loud quasar PKS 0637-752 (z = 0.654) was the first celestial object observed with the Chandra X-ray Observatory, offering the early surprise of the detection of a remarkable X-ray jet. Several observations with a variety of detector configurations contribute to a total exposure time with the Chandra Advanced CCD Imaging Spectrometer (ACIS; Garmire et al. 2000, in preparation) of about 100ks. A spatial analysis of all the available X-ray data, making use of Chandra's spatial resolving power of about 0.4 arcsec, reveals a jet that extends about 10 arcsec to the west of the nucleus. At least four X-ray knots are resolved along the jet, which contains about 5% of the overall X-ray luminosity of the source. Previous observations of PKS 0637-752 in the radio band (Tingay et al. 1998) had identified a kpc-scale radio jet extending to the West of the quasar. The X-ray and radio jets are similar in shape, intensity distribution, and angular structure out to about 9 arcsec, after which the X-ray brightness decreases more rapidly and the radio jet turns abruptly to the north. The X-ray luminosity of the total source is log Lx ~ 45.8 erg/s (2 - 10keV), and appears not to have changed since it was observed with ASCA in November 1996. We present the results of fitting a variety of emission models to the observed spectral distribution, comment on the non-existence of emission lines recently reported in the ASCA observations of PKS 0637-752, and briefly discuss plausible X-ray emission mechanisms.Comment: 24 pages, includes 8 figures, Accepted for publication in Ap

    Establishing consensus on a definition of aphasia: an e-Delphi study of international aphasia researchers

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    Background : Definitions reflect the current state of knowledge about a health condition. An agreed definition of aphasia is central to the progression of the science and clinical practice relevant to aphasia. Aim : To establish consensus on a definition of aphasia. Methods & Procedures : A three-round modified e-Delphi study was conducted with aphasia researchers who were members of the Collaboration of Aphasia Trialists (CATs). In round one, participants were provided with a draft definition developed by the Societal Impact and Reintegration Working Group of CATs. Participants were asked whether they agreed with the definition and were asked to comment on any aspects that they perceived to require amendment. Comments were collated and analysed using inductive content analysis. In round two, participants were presented with the collated and de-identified results of the first round and the participants were asked to vote “yes/no” on two contentious aspects of the definition. In round three, agreement on the revised definition was again sought using closed “yes/no” voting. Consensus was defined a priori as at least 70% agreement by 80% of all CATs members. CATs membership fluctuated across the study period and ranged between 131 and 141 members. Outcomes & Results : The proposed definition was Aphasia is a communication disability due to an acquired impairment of language modalities caused by focal brain damage. Aphasia may affect participation and quality of life of the person with aphasia as well as their family and friends. Aphasia masks competence and affects functioning across relationships, life roles and activities, thereby influencing social inclusion, social connectedness, access to information and services, equal rights, and wellbeing in family, community and culture. Two main categories of proposed amendments to the definition were identified: (1) definition of aphasia as a communication disability versus a language impairment; and (2) definition of aphasia as being the result of a focal and/or diffuse lesion. After three rounds of surveys, consensus was unable to be achieved with an almost even split across participants on both amendment issues. Conclusion : Further debate about the use of the term communication disability to describe aphasia and whether aphasia is a result of focal or diffuse lesions is required before consensus is again attempted
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