1,240 research outputs found

    HST and Spitzer point source detection and optical extinction in powerful narrow-line radio galaxies

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    We present the analysis of infrared HST and Spitzer data for a sample of 13 FRII radio galaxies at 0.03<z<0.11 that are classified as narrow-line radio galaxies (NLRG). In the context of the unified schemes for active galactic nuclei (AGN), our direct view of the AGN in NLRG is impeded by a parsec-scale dusty torus structure. Our high resolution infrared observations provide new information about the degree of extinction induced by the torus, and the incidence of obscured AGN in NLRG. We find that the point-like nucleus detection rate increases from 25 per cent at 1.025μ\mum, to 80 per cent at 2.05μ\mum, and to 100 per cent at 8.0μ\mum. This supports the idea that most NLRG host an obscured AGN in their centre. We estimate the extinction from the obscuring structures using X-ray, near-IR and mid-IR data. We find that the optical extinction derived from the 9.7μ\mum silicate absorption feature is consistently lower than the extinction derived using other techniques. This discrepancy challenges the assumption that all the mid-infrared emission of NLRG is extinguished by a simple screen of dust at larger radii. This disagreement can be explained in terms of either weakening of the silicate absorption feature by (i) thermal mid-IR emission from the narrow-line region, (ii) non-thermal emission from the base of the radio jets, or (iii) by direct warm dust emission that leaks through a clumpy torus without suffering major attenuation.Comment: 18 pages, 7 figures, 8 tables, accepted for publication in MNRA

    Need for redefining needs

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    Defining needs is difficult due to the inherent complexity of the concept of 'need', so it is not surprising that numerous definitions have been proposed. 'Health' consists of a wide range of characteristics so 'health needs' ought to include personal and social care, health care, accommodation, finance, education, employment and leisure, transport and access.Target-driven standards in areas of health care with a high political profile appear to be replacing the concept of universal provision and clinical need; this major change in clinical care warrants a re-evaluation of health care outcomes. Identifying who might benefit from this new approach to health care is equally important if scarce resources are to be fully and appropriately utilised. If the goal of care is 'optimal health', the key marker of success ought to be to ascertain individual patients' health care needs (HCN) and tailor services accordingly. Wide variation in the description of 'needs' directly affects policies and services intended to meet a population's health care needs. Consequently, the definition of 'needs' has important implications for healthcare provision- the more constrained the definition, the less healthcare will be made available and vice versa. This paper describes some common definitions of needs and discusses their respective benefits and disadvantages in terms of health care provision and their potential impact on health polic

    Is quality of life measurement likely to be a proxy for health needs assessment in patients with coronary artery disease?

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    BACKGROUND: The identification of patients' health needs is pivotal in optimising the quality of health care, increasing patient satisfaction and directing resource allocation. Health needs are complex and not so easily evaluated as health-related quality of life (HRQL), which is becoming increasingly accepted as a means of providing a more global, patient-orientated assessment of the outcome of health care interventions than the simple medical model. The potential of HRQL as a surrogate measure of healthcare needs has not been evaluated. OBJECTIVES AND METHOD: A generic (Short Form-12; SF-12) and a disease-specific questionnaire (Seattle Angina Questionnaire; SAQ) were tested for their potential to predict health needs in patients with acute coronary disease. A wide range of healthcare needs were determined using a questionnaire specifically developed for this purpose. RESULTS: With the exception of information needs, healthcare needs were highly correlated with health-related quality of life. Patients with limited enjoyment of personal interests, weak financial situation, greater dependency on others to access health services, and dissatisfaction with accommodation reported poorer HRQL (SF-12: p < 0.001; SAQ: p < 0.01). Difficulties with mobility, aids to daily living and activities requiring assistance from someone else were strongly associated with both generic and disease-specific questionnaires (SF-12: r = 0.46-0.55, p < 0.01; SAQ: r = 0.53-0.65, p < 0.001). Variables relating to quality of care and health services were more highly correlated with SAQ components (r = 0.33-0.59) than with SF-12 (r = 0.07-0.33). Overall, the disease-specific Seattle Angina Questionnaire was superior to the generic Short Form-12 in detecting healthcare needs in patients with coronary disease. Receiver-operator curves supported the sensitivity of HRQL tools in detecting health needs. CONCLUSION: Healthcare needs are complex and developing suitable questionnaires to measure these is difficult and time-consuming. Without a satisfactory means of measuring these needs, the extent to which disease impacts on health will continue to be underestimated. Further investigation on larger populations is warranted but HRQL tools appear to be a reasonable proxy for healthcare needs, as they identify the majority of needs in patients with coronary disease, an observation not previously reported in this patient grou

    Determinants of SME exporting: Insights and implications

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    This study offers insights into determinants of SME exporting according to the characteristics of exporting firms and their resources, thus contributing to a limited literature. The dataset comprised 4,838 respondents from a survey of the UK Federation of Small Businesses. The dependent variable used was two-category (‘do not export’ and ‘export’), allowing a binary logistic multiple regression approach to be used, with separate binomial (logit) regression equations generated for the complete sample and then for different firm age groupings, allowing relationships between exporting and each individual independent variable to be determined whilst holding all other independent variables in the equation constant. The results show that determinants of SME exporting include industry sector, age and the characteristics of the SME owner-manager, along with the firms’ available resources, including the human capital of the owner-manager, use of technology and intellectual property. While an innovation focus was consistently found to be positively linked to exporting, a growth focus was not. These results inform both practice and policy, as the exporting activity of SMEs remains closely linked to economic development policy

    Unmet health needs in patients with coronary heart disease: implications and potential for improvement in caring services

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    BACKGROUND: Improving the quality of health care services requires tailoring facilities to fulfil patients' needs. Satisfying patients' healthcare needs, listening to patients' opinions and building a closer provider-user partnership are central to the NHS. Few published studies have discussed cardiovascular patients' health needs, but they are not comprehensive and fail to explore the contribution of outcome to needs assessment. METHOD: A comprehensive self-administered health needs assessment (HNA) questionnaire was developed for concomitant use with generic (Short Form-12 and EuroQOL) and specific (Seattle Angina Questionnaire) health-related quality of life (HRQL) instruments on 242 patients admitted to the Acute Cardiac Unit, Nottingham. RESULTS: 38% reported difficulty accessing health facilities, 56% due to transport and 32% required a travelling companion. Mean HRQOL scores were lower in those living alone (P < 0.05) or who reported unsatisfactory accommodation. Dissatisfaction with transport affected patients' ease of access to healthcare facilities (P < 0.001). Younger patients (<65 y) were more likely to be socially isolated (P = 0.01). Women and patients with chronic disease were more likely to be concerned about housework (P < 0.05). Over 65 s (p < 0.05) of higher social classes (p < 0.01) and greater physical needs (p < 0.001) had more social needs, correlating moderately (0.32 < r < 0.63) with all HRQL domains except SAQ-AS. Several HRQL components were highly correlated with the HNA physical score (p < 0.001). CONCLUSIONS: Patients wanted more social (suitable accommodation, companionship, social visits) and physical (help aids, access to healthcare services, house work) support. The construct validity and intra-class reliability of the HNA tool were confirmed. Our results indicate a gap between patients' health needs and available services, highlighting potential areas for improvement in the quality of service

    Science at mid-infrared wavelengths with large telescopes

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    For background-limited observations such as those at mid-infrared wavelengths, an increase in telescope aperture not only improves the angular resolution (as it does at all wavelengths) but also leads to very large increases in sensitivity because of the reduced background within the diffraction-limited point spread function. In this presentation we look at the magnitude of that increase for several different operational modes of mid-infrared instrumentation, and we consider some of the implications for science on the current generation of 8-10 meter telescopes

    Distribution of dust clouds around the central engine of NGC 1068

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    We studied the distribution of dust clouds around the central engine of NGC 1068 based on shifted-and-added 8.8 - 12.3 micron (MIR) multi-filter images and 3.0 - 3.9 micron (L-band) spectra obtained with the Subaru Telescope. In a region of 100 pc (1.4") around the central peak, we successfully constructed maps of color temperatures and emissivities of the MIR and L-band continua as well as the 9.7 micron and 3.4 micron dust features with spatial resolutions of 26 pc (0.37") in the MIR and 22 pc (0.3") in the L-band. Our main results are: 1) color temperature of the MIR continuum scatters around the thermal equilibrium temperature with the central engine as the heat source while that of the L-band continuum is higher and independent upon distance from the central engine; 2) the peak of the 9.7 micron silicate absorption feature is shifted to a longer wavelength at some locations; 3) the ratio of the optical depths of the dust features is different from the Galactic values and show complicated spatial distribution; and 4) there is a pie shaped warm dust cloud as an enhancement in the emissivity of the MIR continuum extending about 50 pc to the north from the central engine. We speculate that material falls into the central engine through this cloud.Comment: 26 pages, 9 figures. Accepted for publication on Ap

    Born Again Protoplanetary Disk Around Mira B

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    The Mira AB system is a nearby (~107 pc) example of a wind accreting binary star system. In this class of system, the wind from a mass-losing red giant star (Mira A) is accreted onto a companion (Mira B), as indicated by an accretion shock signature in spectra at ultraviolet and X-ray wavelengths. Using novel imaging techniques, we report the detection of emission at mid-infrared wavelengths between 9.7 and 18.3 μ\mum from the vicinity of Mira B but with a peak at a radial position about 10 AU closer to the primary Mira A. We interpret the mid-infrared emission as the edge of an optically-thick accretion disk heated by Mira A. The discovery of this new class of accretion disk fed by M-giant mass loss implies a potential population of young planetary systems in white-dwarf binaries which has been little explored, despite being relatively common in the solar neighborhood.Comment: Accepted for Ap

    Optical and Infrared Spectroscopy of the type IIn SN 1998S : Days 3-127

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    We present contemporary infrared and optical spectroscopic observations of the type IIn SN 1998S for the period between 3 and 127 days after discovery. In the first week the spectra are characterised by prominent broad emission lines with narrow peaks superimposed on a very blue continuum(T~24000K). In the following two weeks broad, blueshifted absorption components appeared in the spectra and the temperature dropped. By day 44, broad emission components in H and He reappeared in the spectra. These persisted to 100-130d, becoming increasingly asymmetric. We agree with Leonard et al. (2000) that the broad emission lines indicate interaction between the ejecta and circumstellar material (CSM) and deduce that progenitor of SN 1998S appears to have gone through at least two phases of mass loss, giving rise to two CSM zones. Examination of the spectra indicates that the inner zone extended to <90AU, while the outer CSM extended from 185AU to over 1800AU. Analysis of high resolution spectra shows that the outer CSM had a velocity of 40-50 km/s. Assuming a constant velocity, we can infer that the outer CSM wind commenced more than 170 years ago, and ceased about 20 years ago, while the inner CSM wind may have commenced less than 9 years ago. During the era of the outer CSM wind the outflow was high, >2x10^{-5}M_{\odot}/yr corresponding to a mass loss of at least 0.003M_{\odot} and suggesting a massive progenitor. We also model the CO emission observed in SN 1998S. We deduce a CO mass of ~10^{-3} M_{\odot} moving at ~2200km/s, and infer a mixed metal/He core of ~4M_{\odot}, again indicating a massive progenitor.Comment: 22 pages, 14 figures, accepted in MNRA

    A multi-wavelength view of the central kiloparsec region in the Luminous Infrared Galaxy NGC1614

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    The Luminous Infrared Galaxy NGC1614 hosts a prominent circumnuclear ring of star formation. However, the nature of the dominant emitting mechanism in its central ~100 pc is still under debate. We present sub-arcsecond angular resolution radio, mid-infrared, Pa-alpha, optical, and X-ray observations of NGC1614, aimed at studying in detail both the circumnuclear ring and the nuclear region. The 8.4 GHz continuum emission traced by the Very Large Array (VLA) and the Gemini/T-ReCS 8.7 micron emission, as well as the Pa-alpha line emission, show remarkable morphological similarities within the star-forming ring, suggesting that the underlying emission mechanisms are tightly related. We used an HST/NICMOS Pa-alpha map of similar resolution to our radio maps to disentangle the thermal free-free and non-thermal synchrotron radio emission, from which we obtained the intrinsic synchrotron power-law for each individual region within the central kpc of NGC1614. The radio ring surrounds a relatively faint, steep-spectrum source at the very center of the galaxy, suggesting that the central source is not powered by an AGN, but rather by a compact (r < 90 pc) starburst. Chandra X-ray data also show that the central kpc region is dominated by starburst activity, without requiring the existence of an AGN. We also used publicly available infrared data to model-fit the spectral energy distribution of both the starburst ring and a putative AGN in NGC1614. In summary, we conclude that there is no need to invoke an AGN to explain the observed bolometric properties of the galaxy.Comment: 13 pages, 7 figures, 5 tables. Accepted for publication in Ap
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