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- Ueta, T., et al.
(author)
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Herschel Planetary Nebula Survey (HerPlaNS)
- 2014
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In: Asymmetrical Planetary Nebulae VI conference, Proceedings of the conference held 4-8 November, 2013. ; , s. 106-
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Conference paper (other academic/artistic)abstract
- The Herschel Planetary Nebula Survey (HerPlaNS) is one of the largest Open Time programs carried out by the Herschel Space Observatory, by which we simultaneously probe the dust and gas components of the circumstellar environments of evolved stars. HerPlaNS is part of a community-wide panchromatic (from X-ray to Radio) observational initiative to furnish substantial PN data resources that would allow us - PN astronomers - to tackle a multitude of issues in PN physics. In this contribution we will give a general overview of the survey and a glimpse of what the data can tell us using NGC 6781 as an example.
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- Ueta, T., et al.
(author)
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Planetary Nebula dust haloes revealed by Herschel
- 2013
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In: Proceedings of Science. - Trieste, Italy : Sissa Medialab. - 1824-8039.
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Conference paper (peer-reviewed)abstract
- Herschel Planetary Nebula Survey (HerPlaNS) is a far-IR imaging and spectroscopic survey of planetary nebulae, performedwith the Herschel Space Observatory, aiming at (1) establishing the spatially-resolved far-IR characteristics of the target nebulae and (2) understanding the energetics and shaping history of the circumstellar nebulae. Below we briefly demonstrate the breadth and depth of the HerPlaNS data set using one of the targets, NGC6781, as an example, and explore expectations in the era of SPICA, the next-generation far-IR mission.
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- Ueta, T., et al.
(author)
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The Herschel Planetary Nebula Survey (HerPlaNS) I. Data overview and analysis demonstration with NGC 6781
- 2014
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 565, s. A36-
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Journal article (peer-reviewed)abstract
- Context. This is the first of a series of investigations into far-IR characteristics of 11 planetary nebulae (PNe) under the Herschel Space Observatory open time 1 program, Herschel Planetary Nebula Survey (HerPlaNS). Aims. Using the HerPlaNS data set, we look into the PN energetics and variations of the physical conditions within the target nebulae. In the present work, we provide an overview of the survey, data acquisition and processing, and resulting data products. Methods. We performed (1) PACS/SPIRE broadband imaging to determine the spatial distribution of the cold dust component in the target PNe and (2) PACS/SPIRE spectral-energy-distribution and line spectroscopy to determine the spatial distribution of the gas component in the target PNe. Results. For the case of NGC 6781, the broadband maps confirm the nearly pole-on barrel structure of the amorphous carbon-rich dust shell and the surrounding halo having temperatures of 26-40 K. The PACS/SPIRE multiposition spectra show spatial variations of far-.IR lines that reflect the physical stratification of the nebula. We demonstrate that spatially resolved far-IR line diagnostics yield the (T-e, n(e)) profiles, from which distributions of ionized, atomic, and molecular gases can be determined. Direct comparison of the dust and gas column mass maps constrained by the HerPlaNS data allows to construct an empirical gas-to-dust mass ratio map, which shows a range of ratios with the median of 195 +/- 110. The present analysis yields estimates of the total mass of the shell to be 0.86 M-circle dot, consisting of 0.54 M-circle dot of ionized gas, 0.12 M-circle dot of atomic gas, 0.2 M-circle dot of molecular gas, and 4 x 10(-3) M-circle dot of dust grains. These estimates' also suggest that the central star of about 1.5 M-circle dot initial mass is terminating its PN evolution onto the white dwarf cooling track. Conclusions. The HerPlaNS data provide various diagnostics for both the dust and gas components in a spatially resolved manner. In the forthcoming papers of the HerPlaNS series we will explore the HerPlaNS data set fully for the entire sample of 11 PNe.
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- Estes, James A., et al.
(author)
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Trophic Downgrading of Planet Earth
- 2011
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In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 333:6040, s. 301-306
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Research review (peer-reviewed)abstract
- Until recently, large apex consumers were ubiquitous across the globe and had been for millions of years. The loss of these animals may be humankind's most pervasive influence on nature. Although such losses are widely viewed as an ethical and aesthetic problem, recent research reveals extensive cascading effects of their disappearance in marine, terrestrial, and freshwater ecosystems worldwide. This empirical work supports long-standing theory about the role of top-down forcing in ecosystems but also highlights the unanticipated impacts of trophic cascades on processes as diverse as the dynamics of disease, wildfire, carbon sequestration, invasive species, and biogeochemical cycles. These findings emphasize the urgent need for interdisciplinary research to forecast the effects of trophic downgrading on process, function, and resilience in global ecosystems.
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- Holmberg, Lars, et al.
(author)
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A comparison of prostate cancer survival in England, Norway and Sweden : A population-based study
- 2012
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In: Cancer Epidemiology. - : Elsevier BV. - 1877-7821 .- 1877-783X. ; 36:1, s. e7-e12
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Journal article (peer-reviewed)abstract
- Purpose The objective of the study was to compare patterns of survival 2001-2004 in prostate cancer patients from England, Norway and Sweden in relation to age and period of follow-up. Subjects and methods Excess mortality in men with prostate cancer was estimated using nation-wide cancer register data using a period approach for relative survival. 179,112 men in England, 23,192 in Norway and 59,697 in Sweden were included. Results In all age groups, England had the lowest survival, particularly so among men aged 80+. Overall age-standardised five-year survival was 76.4%, 80.3% and 83.0% for England, Norway and Sweden, respectively. The majority of the excess deaths in England were confined to the first year of follow-up. Conclusion The results indicate that a small but important group of older patients present at a late stage and succumb early to their cancers, possibly in combination with severe comorbidity, and this situation is more common in England than in Norway or Sweden.
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