48 research outputs found

    Bronchial Challenge Testing

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    High-Spatial Resolution SED of NGC 1068 from Near-IR to Radio. Disentangling the thermal and non-thermal contributions

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    We investigate the ideas that a sizable fraction of the interferometrically unresolved infrared emission of the nucleus of NGC 1068 might originate from other processes than thermal dust emission from the torus. We examine the contribution of free-free or synchrotron emissions to the central mid- and near-IR parsec-scale emitting region of NGC 1068. Each mechanism is constrained with parsec scale radio data available for NGC 1068 in the 10^9 - 10^11 Hz regime, and compared to the highest-resolution interferometric data available in the mid-infrared. It is shown that the unresolved emission in the interferometric observation (<~1pc) is still dominatedd by dust emission and not by contributions from synchrotron or free-free emission. As recent studies suggest, the interferometric observations prefer a clumpy structure of the dust distribution. Extrapolation of the radio free-free or synchrotron emission to the IR indicates that their contribution is <20% even for the unresolved fraction of the interferometric flux. The slope of the available radio data is consistent with a power law exponent alpha = 0.29 +/- 0.07 which we interprete in terms of either free-free emission or synchrotron radiation from quasi-monochromatic electrons. We apply emission models for both mechanisms in order to obtain physical parameters. (abridged)Comment: 8 pages, 3 figures; accepted by A&

    AGN dust tori at low and high luminosities

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    A cornerstone of AGN unification schemes is the presence of an optically and geometrically thick dust torus. It provides the obscuration to explain the difference between type 1 and type 2 AGN. We investigate the influence of the dust distribution on the Eddington limit of the torus. For smooth dust distributions, the Eddingtion limit on the dust alone is 5 orders of magnitudes below the limit for electron scattering in a fully ionized plasma, while a clumpy dust torus has an Eddington limit slightly larger than the classical one. We study the behaviour of a clumpy torus at low and high AGN luminosities. For low luminosities of the order of ~10^42 erg/s, the torus changes its characteristics and obscuration becomes insufficient. In the high luminosity regime, the clumpy torus can show a behaviour which is consistent with the "receding torus" picture. The derived luminosity-dependent fraction of type-2-objects agrees with recent observational results. Moreover, the luminosity-dependent covering factor in a clumpy torus may explain the presence of broad-line AGN with high column densities in X-rays.Comment: 5 pages, 0 figures; Accepted for publication in MNRA

    Smoking Prevalence Increases following Canterbury Earthquakes

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    Background. A magnitude 7.1 earthquake hit Canterbury in September 2010. This earthquake and associated aftershocks took the lives of 185 people and drastically changed residents’ living, working, and social conditions. Aim. To explore the impact of the earthquakes on smoking status and levels of tobacco consumption in the residents of Christchurch. Methods. Semistructured interviews were carried out in two city malls and the central bus exchange 15 months after the first earthquake. A total of 1001 people were interviewed. Results. In August 2010, prior to any earthquake, 409 (41%) participants had never smoked, 273 (27%) were currently smoking, and 316 (32%) were ex-smokers. Since the September 2010 earthquake, 76 (24%) of the 316 ex-smokers had smoked at least one cigarette and 29 (38.2%) had smoked more than 100 cigarettes. Of the 273 participants who were current smokers in August 2010, 93 (34.1%) had increased consumption following the earthquake, 94 (34.4%) had not changed, and 86 (31.5%) had decreased their consumption. 53 (57%) of the 93 people whose consumption increased reported that the earthquake and subsequent lifestyle changes as a reason to increase smoking. Conclusion. 24% of ex-smokers resumed smoking following the earthquake, resulting in increased smoking prevalence. Tobacco consumption levels increased in around one-third of current smokers

    Stakeholders’ Perspectives on the Quality of End-of-Life Health Care Services for Chronic Obstructive Airways Disease: A Focus Group Study

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    Introduction: Delivery of end-of-life care for severe chronic obstructive pulmonary disease (COPD) has been hampered by an unpredictable disease trajectory and poor integration of health care and social services. Objective: To critically explore the perspectives, values, and experiences of stakeholders in COPD end-of-life healthcare services in a large district in Aotearoa New Zealand. Design: Focus groups analysed utilising critical theory and Actor-Network Theory. Methods: Stakeholders in end-of-life COPD healthcare services were purposively sampled from a large healthcare network in Canterbury, Aotearoa New Zealand to participate in seven focus groups (bereaved carers, community-based health professionals, non-Māori, non-Pacific patients, and support people (two groups), Māori patients, supporters and health professionals, Pacific patients, support people and health professionals, and hospital-based health professionals). Participants discussed end-of-life care services for people with COPD. Transcripts were coded utilising descriptive and structural coding to develop themes related to provision of quality care. Participants were positioned as experts. We considered how the themes arising supported and disrupted the healthcare network for end-of-life COPD. Results: Five themes related to quality of care for end-of-life COPD were identified: compassion, competence, community, commitment, and collaboration. The absence of any of these five themes required for quality care led to power imbalances within healthcare systems. Power inequities created disconnection among stakeholders which then disrupted commitment, community, and collaboration. A dysfunctional healthcare network impeded compassion between stakeholders and did not support their competence, leading to lower quality care. All five themes were identified as essential to delivery of high-quality end-of-life care in COPD. Conclusion: Stakeholders’ perspectives of end-of-life care for COPD identified of core features of a health system network that enabled or impeded the actions of stakeholders and allocation of resources to provide quality care

    The small dispersion of the mid IR -- hard X-ray correlation in AGN

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    Context: We investigate mid-infrared and X-ray properties of the dusty torus in unification scenarios for active galactic nuclei. Aims: We use the relation between mid IR and hard X-ray luminosities to constrain AGN unification scenarios. Methods: With VISIR at the VLT, we have obtained the currently highest angular resolution (0".35 FWHM) narrow-band mid infrared images of the nuclei of 8 nearby Seyfert galaxies. Combining these observations with X-ray data from the literature we study the correlation between their mid IR and hard X-ray luminosities. Results: We find that the rest frame 12.3 mircon (L_MIR) and 2-10 keV (L_X) luminosities are correlated at a highly significant level. The best fit power-law to our data is log L_MIR \propto (1.60 \pm 0.22) log L_X, showing a much smaller dispersion than earlier studies. Conclusions: The similarity in the og L_MIR / log L_X ratio between Sy1s and Sy2s even using high angular resolution MIR data implies that the similarity is intrinsic to AGN and not caused by contamination from extra-nuclear emission. This supports clumpy torus models. The exponent of the correlation constrains the inner geometry of the torus.Comment: 5 pages, 3 figures, accepted for publication in Astronomy & Astrophysic

    Interstellar gas within ∌10\sim 10 pc of Sgr A∗^*

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    We seek to obtain a coherent and realistic three-dimensional picture of the interstellar gas out to about 10 pc of the dynamical center of our Galaxy, which is supposed to be at Sgr A∗^*. We review the existing observational studies on the different gaseous components that have been identified near Sgr A∗^*, and retain all the information relating to their spatial configuration and/or physical state. Based on the collected information, we propose a three-dimensional representation of the interstellar gas, which describes each component in terms of both its precise location and morphology and its thermodynamic properties. The interstellar gas near Sgr A∗^* can represented by five basic components, which are, by order of increasing size: (1) a central cavity with roughly equal amounts of warm ionized and atomic gases, (2) a ring of mainly molecular gas, (3) a supernova remnant filled with hot ionized gas, (4) a radio halo of warm ionized gas and relativistic particles, and (5) a belt of massive molecular clouds. While the halo gas fills ≈80\approx 80% of the studied volume, the molecular components enclose ≈98\approx 98% of the interstellar mass.Comment: 21 pages, 7 figure

    Severe COPD and the transition to a palliative approach

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    Patients with severe chronic obstructive pulmonary disease (COPD) have a chaotic trajectory towards death. Research has focused on identifying a “transition point” that would allow identification of those patients who may benefit from a palliative approach to their care, or referral to a specialist palliative care service. This article aims to outline difficulties in identifying this transition point, summarise current literature on this topic and suggests a model based on clinical milestones. Educational aims To outline the difficulties associated with identifying patients with severe COPD who are at risk of dying. To summarise current research on this topic. Key points A specific transition point is difficult to identify in severe COPD. Tools are available that may assist the physician in identifying those at risk of dying. It is essential that the patient voice is heard, patients can describe specific events that may be used as a “trigger” for a palliative approach. Specialist palliative care services may only be required for a subgroup of patients whose needs cannot be managed by the primary care team
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