| 1. |
- Keppler, M., et al.
(author)
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Discovery of a planetary-mass companion within the gap of the transition disk around PDS 70
- 2018
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 617
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Journal article (peer-reviewed)abstract
- Context. Young circumstellar disks are the birthplaces of planets. Their study is of prime interest to understand the physical and chemical conditions under which planet formation takes place. Only very few detections of planet candidates within these disks exist, and most of them are currently suspected to be disk features.Aims. In this context, the transition disk around the young star PDS 70 is of particular interest, due to its large gap identified in previous observations, indicative of ongoing planet formation. We aim to search for the presence of an embedded young planet and search for disk structures that may be the result of disk-planet interactions and other evolutionary processes.Methods. We analyse new and archival near-infrared images of the transition disk PDS 70 obtained with the VLT/SPHERE, VLT/NaCo, and Gemini/NICI instruments in polarimetric differential imaging and angular differential imaging modes.Results. We detect a point source within the gap of the disk at about 195 mas (similar to 22 au) projected separation. The detection is confirmed at five different epochs, in three filter bands and using different instruments. The astrometry results in an object of bound nature, with high significance. The comparison of the measured magnitudes and colours to evolutionary tracks suggests that the detection is a companion of planetary mass. The luminosity of the detected object is consistent with that of an L-type dwarf, but its IR colours are redder, possibly indicating the presence of warm surrounding material. Further, we confirm the detection of a large gap of similar to 54 au in size within the disk in our scattered light images, and detect a signal from an inner disk component. We find that its spatial extent is very likely smaller than similar to 17 au in radius, and its position angle is consistent with that of the outer disk. The images of the outer disk show evidence of a complex azimuthal brightness distribution which is different at different wavelengths and may in part be explained by Rayleigh scattering from very small grains.Conclusions. The detection of a young protoplanet within the gap of the transition disk around PDS 70 opens the door to a so far observationally unexplored parameter space of planetary formation and evolution. Future observations of this system at different wavelengths and continuing astrometry will allow us to test theoretical predictions regarding planet-disk interactions, planetary atmospheres, and evolutionary models.
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| 2. |
- Singh, G., et al.
(author)
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Revealing asymmetrical dust distribution in the inner regions of HD 141569
- 2021
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 653
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Journal article (peer-reviewed)abstract
- Context. The combination of high-contrast imaging with spectroscopy and polarimetry offers a pathway to studying the grain distribution and properties of debris disks in exquisite detail. Here, we focus on the case of a gas-rich debris disk around HD 141569A, which features a multiple-ring morphology first identified with SPHERE in the near-infrared.Aims. We obtained polarimetric differential imaging with SPHERE in the H-band to compare the scattering properties of the innermost ring at 44 au with former observations in total intensity with the same instrument. In polarimetric imaging, we observed that the intensity of the ring peaks in the south-east, mostly in the forward direction, whereas in total intensity imaging, the ring is detected only at the south. This noticeable characteristic suggests a non-uniform dust density in the ring. With these two sets of images, we aim to study the distribution of the dust to solve for the actual dust distribution.Methods. We implemented a density function varying azimuthally along the ring and generated synthetic images both in polarimetry and in total intensity, which are then compared to the actual data. The search for the best-fit model was performed both with a grid-based and an MCMC approach. Using the outcome of this modelization, we further measured the polarized scattering phase function for the observed scattering angle between 33 degrees and 147 degrees as well as the spectral reflectance of the southern part of the ring between 0.98 and 2.1 mu m. We tentatively derived the grain properties by comparing these quantities with MCFOST models and assuming Mie scattering.Results. We find that the dust density peaks in the south-west at an azimuthal angle of 220 degrees similar to 238 degrees with a rather broad width of 61 degrees similar to 127 degrees. The difference in the intensity distributions observed in polarimetry and total intensity is the result of this particular morphology. Although there are still uncertainties that remain in the determination of the anisotropic scattering factor, the implementation of an azimuthal density variation to fit the data proved to be robust. Upon elaborating on the origin of this dust density distribution, we conclude that it could be the result of a massive collision when we account for the effect of the high gas mass that is present in the system on the dynamics of grains. In terms of grain composition, our preliminary interpretation indicates a mixture of porous sub-micron sized astro-silicate and carbonaceous grains.Conclusions. The SPHERE observations have allowed, for the first time, for meaningful constraints to be placed on the dust distribution beyond the standard picture of a uniform ring-like debris disk. However, future studies with a multiwavelength approach and additional detailed modeling would be required to better characterize the grain properties in the HD 141569 system.
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| 3. |
- Pittman, S. J., et al.
(author)
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Seascape ecology : identifying research priorities for an emerging ocean sustainability science
- 2021
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In: Marine Ecology Progress Series. - : INTER-RESEARCH. - 0171-8630 .- 1616-1599. ; 663, s. 1-29
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Journal article (peer-reviewed)abstract
- Seascape ecology, the marine-centric counterpart to landscape ecology, is rapidly emerging as an interdisciplinary and spatially explicit ecological science with relevance to marine management, bio-diversity conservation, and restoration. While important progress in this field has been made in the past decade, there has been no coherent prioritisation of key research questions to help set the future research agenda for seascape ecology. We used a 2-stage modified Delphi method to solicit applied research questions from academic experts in seascape ecology and then asked respondents to identify priority questions across 9 interrelated research themes using 2 rounds of selection. We also invited senior management/conservation practitioners to prioritise the same research questions. Analyses highlighted congruence and discrepancies in perceived priorities for applied research. Themes related to both ecological concepts and management practice, and those identified as priorities include seascape change, seascape connectivity, spatial and temporal scale, ecosystem-based management, and emerging technologies and metrics. Highest-priority questions (upper tercile) received 50% agreement between respondent groups, and lowest priorities (lower tercile) received 58% agreement. Across all 3 priority tiers, 36 of the 55 questions were within a +/- 10% band of agreement. We present the most important applied research questions as determined by the proportion of votes received. For each theme, we provide a synthesis of the research challenges and the potential role of seascape ecology. These priority questions and themes serve as a roadmap for advancing applied seascape ecology during, and beyond, the UN Decade of Ocean Science for Sustainable Development (2021-2030).
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| 4. |
- Rieth, M., et al.
(author)
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A brief summary of the progress on the EFDA tungsten materials program
- 2013
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In: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 442:1-3, s. S173-S180
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Journal article (peer-reviewed)abstract
- The long-term objective of the European Fusion Development Agreement (EFDA) fusion materials programme is to develop structural and armor materials in combination with the necessary production and fabrication technologies for reactor concepts beyond the International Thermonuclear Experimental Reactor. The programmatic roadmap is structured into four engineering research lines which comprise fabrication process development, structural material development, armor material optimization, and irradiation performance testing, which are complemented by a fundamental research programme on "Materials Science and Modeling." This paper presents the current research status of the EFDA experimental and testing investigations, and gives a detailed overview of the latest results on materials research, fabrication, joining, high heat flux testing, plasticity studies, modeling, and validation experiments.
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| 5. |
- Rieth, M., et al.
(author)
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Recent progress in research on tungsten materials for nuclear fusion applications in Europe
- 2013
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In: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 432:1-3, s. 482-500
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Research review (peer-reviewed)abstract
- The current magnetic confinement nuclear fusion power reactor concepts going beyond ITER are based on assumptions about the availability of materials with extreme mechanical, heat, and neutron load capacity. In Europe, the development of such structural and armour materials together with the necessary production, machining, and fabrication technologies is pursued within the EFDA long-term fusion materials programme. This paper reviews the progress of work within the programme in the area of tungsten and tungsten alloys. Results, conclusions, and future projections are summarized for each of the programme's main subtopics, which are: (1) fabrication, (2) structural W materials, (3) W armour materials, and (4) materials science and modelling. It gives a detailed overview of the latest results on materials research, fabrication processes, joining options, high heat flux testing, plasticity studies, modelling, and validation experiments.
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| 6. |
- Rieth, M., et al.
(author)
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Review on the EFDA programme on tungsten materials technology and science
- 2011
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In: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 417:1-3, s. 463-467
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Journal article (peer-reviewed)abstract
- All the recent DEMO design studies for helium cooled divertors utilize tungsten materials and alloys, mainly due to their high temperature strength, good thermal conductivity, low erosion, and comparably low activation under neutron irradiation. The long-term objective of the EFDA fusion materials programme is to develop structural as well as armor materials in combination with the necessary production and fabrication technologies for future divertor concepts. The programmatic roadmap is structured into four engineering research lines which comprise fabrication process development, structural material development, armor material optimization, and irradiation performance testing, which are complemented by a fundamental research programme on "Materials Science and Modeling". This paper presents the current research status of the EFDA experimental and testing investigations, and gives a detailed overview of the latest results on fabrication, joining, high heat flux testing, plasticity, modeling, and validation experiments.
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| 7. |
- Siersma, V., et al.
(author)
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Importance of factors determining the low health-related quality of life in people presenting with a diabetic foot ulcer: the Eurodialestudy
- 2013
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In: Diabetic Medicine. - : Wiley. - 1464-5491 .- 0742-3071. ; 30:11, s. 1382-1387
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Journal article (peer-reviewed)abstract
- AimTo identify the factors responsible for the low health-related quality of life associated with foot ulcers and the relative importance of these factors. MethodsA total of 1232 patients with a new foot ulcer, who presented at one of the 14 centres in 10 European countries participating in the Eurodiale study, were included in this cross-sectional study. Patient and ulcer characteristics were obtained as well as results from the Euro-Qol-5D questionnaire, a health-related quality of life instrument with five domains (mobility, self-care, usual activities, pain/discomfort and anxiety/depression). To analyse the relative importance of comorbidities and ulcer- and patient-related factors for health-related quality of life, linear regression models were used to calculate the relative contributions of each factor to the fit (R-2) of the model. ResultsPatients reported poor overall health-related quality of life, with problems primarily in the mobility and pain/discomfort domains. Among the comorbidities, the inability to stand or walk without help was the most important determinant of decreased health-related quality of life in all five domains. Among ulcer-related factors, ulcer size, limb-threatening ischaemia and elevated C-reactive protein concentration also had high importance in all domains. The clinical diagnosis of infection, peripheral arterial disease and polyneuropathy were only important in the pain/discomfort domain. ConclusionsThe factors that determine health-related quality of life are diverse and to an extent not disease-specific. To improve health-related quality of life, treatment should not only be focused on ulcer healing but a multifactorial approach by a specialized multidisciplinary team is also important. What's new? The inability to stand or walk without help is the most important determinant of poor health-related quality of life. Other factors with high importance are ulcer size, elevated C-reactive protein concentration and limb-threatening ischaemia. To improve health-related quality of life, treatment should not only be focused on ulcer healing but a multifactorial approach by a specialized multidisciplinary team is also important.
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| 8. |
- Due, P., et al.
(author)
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Socioeconomic position, macroeconomic environment and overweight among adolescents in 35 countries
- 2009
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In: International Journal of Obesity. - : Springer Science and Business Media LLC. - 1476-5497 .- 0307-0565. ; 33:10, s. 1084-1093
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Journal article (peer-reviewed)abstract
- Objective: It is important to understand levels and social inequalities in childhood overweight within and between countries. This study examined prevalence and social inequality in adolescent overweight in 35 countries, and associations with macroeconomic factors. Design: International cross-sectional survey in national samples of schools. Subjects: A total of 11-, 13- and 15-year-olds from 35 countries in Europe and North America in 2001-2002 (N = 162 305). Measurements: The main outcome measure was overweight based on self-reported height and weight ( body mass index cut-points corresponding to body mass index of 25 kg/m(2) at the age of 18 years). Measures included family and school affluence (within countries), and average country income and economic inequality (between countries). Results: There were large variations in adolescent overweight, from 3.5% in Lithuanian girls to 31.7% in boys from Malta. Prevalence of overweight was higher among children from less affluent families in 21 of 24 Western and 5 of 10 Central European countries. However, children from more affluent families were at higher risk of overweight in Croatia, Estonia and Latvia. In Poland, Lithuania, Macedonia and Finland, girls from less affluent families were more overweight whereas the opposite was found for boys. Average country income was associated with prevalence and inequality in overweight when considering all countries together. However, economic inequality as measured by the Gini coefficient was differentially associated with prevalence and socioeconomic inequality in overweight among the 23-high income and 10-middle income countries, with a positive relationship among the high income countries and a negative association among the middle income countries. Conclusion: The direction and magnitude of social inequality in adolescent overweight shows large international variation, with negative social gradients in most countries, but positive social gradients, especially for boys, in some Central European countries. Macroeconomic factors are associated with the heterogeneity in prevalence and social inequality of adolescent overweight. International Journal of Obesity (2009) 33, 1084-1093; doi:10.1038/ijo.2009.128; published online 21 July 2009
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| 9. |
- Ginski, C., et al.
(author)
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An extended scattered light disk around AT Pyx. Possible planet formation in a cometary globule
- 2022
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 662
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Journal article (peer-reviewed)abstract
- Aims. To understand how the multitude of planetary systems that have been discovered come to be, we need to study systems at different evolutionary stages, with different central stars but also in different environments. The most challenging environment for planet formation may be the harsh UV radiation field of nearby massive stars which quickly erodes disks by external photo-evaporation. We observed the AT Pyx system, located in the head of a cometary globule in the Gum Nebula, to search for signs of ongoing planet formation.Methods. We used the extreme adaptive optics imager VLT/SPHERE in Dual Beam Polarization Imaging Mode in H-band as well as in IRDIFS Extended mode (K12-band imaging and Y-H integral field spectroscopy) to observe AT Pyx in polarized light and total intensity. Additionally, we employed VLT/NACO to observe the system in the L-band.Results. We resolve the disk around AT Pyx for the first time in scattered light across multiple wavelengths in polarized light and total intensity. We find an extended (≥126 au) disk, with an intermediate inclination of between 35° and 42°. The disk shows a complex substructure and we identify two or possibly three spiral-like features. Depending on the precise geometry of the disk (which we cannot unambiguously infer from our data), the disk may be eccentric with an eccentricity of ~0.16 or partially self-shadowed. The spiral features and possible eccentricity are both consistent with signatures of an embedded gas giant planet with a mass of ~1 MJup. Our own observations can rule out brown dwarf companions embedded in the resolved disk, but are nevertheless not sensitive enough to confirm or rule out the presence of a gas giant.Conclusions. AT Pyx is the first disk to be spatially resolved in a cometary globule in the Gum Nebula. By comparison with disks in the Orion Nebula Cluster we note that the extension of the disk may be exceptional for this environment if the external UV radiation field is indeed comparable to other cometary globules in the region. The signposts of ongoing planet formation are intriguing and need to be followed up with either higher sensitivity or at different wavelengths.
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| 10. |
- Pickwell, K., et al.
(author)
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Minor amputation does not negatively affect health-related quality of life as compared with conservative treatment in patients with a diabetic foot ulcer : An observational study
- 2017
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In: Diabetes/Metabolism Research and Reviews. - : Wiley. - 1520-7552. ; 33:3
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Journal article (peer-reviewed)abstract
- Background: Health-related quality of life (HRQoL) is poor in patients with persistent diabetic foot ulcers and poor HRQoL predicts worse outcomes in these patients. Amputation is often considered a treatment failure, which is why conservative treatment is generally preferred over amputation. However, it is unclear whether minor amputation negatively affects HRQoL compared with conservative treatment in patients with diabetic foot ulcers. Methods: In the cohort of the multicenter, prospective, observational Eurodiale study, we determined difference in change of HRQoL measured by EQ-5D between patients with a diabetic foot ulcers that healed after conservative treatment (n = 676) and after minor amputation (n = 145). Propensity score was used to adjust for known confounders, attempting to overcome lack of randomization. Results: Baseline HRQoL was not significantly different between patients treated conservatively and undergoing minor amputation. In addition, there was no difference in the change of HRQoL between these groups. In patients who healed 6 to 12 months after the first visit, HRQoL on the anxiety/depression subscale even appeared to improve more in those who underwent minor amputation. Conclusions: Minor amputation was not associated with a negative impact on HRQoL in patients with a diabetic foot ulcers. It may therefore not be considered treatment failure in terms of HRQoL but rather a viable treatment option. A randomized controlled trial is warranted to further examine the influence of minor amputations on health-related quality of life.
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