| 1. |
- Jönsson, Henrik, et al.
(författare)
-
Abundances of disk and bulge giants from high-resolution optical spectra I. O, Mg, Ca, and Ti in the solar neighborhood and Kepler field samples
- 2017
-
Ingår i: Astronomy and Astrophysics. - : EDP SCIENCES S A. - 0004-6361 .- 1432-0746. ; 598
-
Tidskriftsartikel (refereegranskat)abstract
- Context. The Galactic bulge is an intriguing and significant part of our Galaxy, but it is hard to observe because it is both distant and covered by dust in the disk. Therefore, there are not many high-resolution optical spectra of bulge stars with large wavelength coverage, whose determined abundances can be compared with nearby, similarly analyzed stellar samples. Aims. We aim to determine the diagnostically important alpha elements of a sample of bulge giants using high-resolution optical spectra with large wavelength coverage. The abundances found are compared to similarly derived abundances from similar spectra of similar stars in the local thin and thick disks. In this first paper we focus on the solar neighborhood reference sample. Methods. We used spectral synthesis to derive the stellar parameters as well as the elemental abundances of both the local and bulge samples of giants. We took special care to benchmark our method of determining stellar parameters against independent measurements of effective temperatures from angular diameter measurements and surface gravities from asteroseismology. Results. In this first paper we present the method used to determine the stellar parameters and elemental abundances, evaluate them, and present the results for our local disk sample of 291 giants. Conclusions. When comparing our determined spectroscopic temperatures to those derived from angular diameter measurements, we reproduce these with a systematic difference of + 10 K and a standard deviation of 53 K. The spectroscopic gravities reproduce those determined from asteroseismology with a systematic off set of + 0.10 dex and a standard deviation of 0.12 dex. When it comes to the abundance trends, our sample of local disk giants closely follows trends found in other works analyzing solar neighborhood dwarfs, showing that the much brighter giant stars are as good abundance probes as the often used dwarfs.
|
|
| 2. |
- Bhatia, Neha, et al.
(författare)
-
Quantitative analysis of auxin sensing in leaf primordia argues against proposed role in regulating leaf dorsoventrality
- 2019
-
Ingår i: eLife. - 2050-084X. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- Dorsoventrality in leaves has been shown to depend on the pre-patterned expression of KANADI and HD-ZIPIII genes within the plant shoot apical meristem (SAM). However, it has also been proposed that asymmetric auxin levels within initiating leaves help establish leaf polarity, based in part on observations of the DII auxin sensor. By analyzing and quantifying the expression of the R2D2 auxin sensor, we find that there is no obvious asymmetry in auxin levels during Arabidopsis leaf development. We further show that the mDII control sensor also exhibits an asymmetry in expression in developing leaf primordia early on, while it becomes more symmetric at a later developmental stage as reported previously. Together with other recent findings, our results argue against the importance of auxin asymmetry in establishing leaf polarity.
|
|
| 3. |
- Briat, C., et al.
(författare)
-
The Conservation of Information, Towards an Axiomatized Modular Modeling Approach to Congestion Control
- 2015
-
Ingår i: IEEE/ACM Transactions on Networking. - 1063-6692 .- 1558-2566. ; 23:3, s. 851-865
-
Tidskriftsartikel (refereegranskat)abstract
- We derive a modular fluid-flow network congestion control model based on a law of fundamental nature in networks: the conservation of information. Network elements such as queues, users, and transmission channels and network performance indicators like sending/acknowledgment rates and delays are mathematically modeled by applying this law locally. Our contributions are twofold. First, we introduce a modular metamodel that is sufficiently generic to represent any network topology. The proposed model is composed of building blocks that implement mechanisms ignored by the existing ones, which can be recovered from exact reduction or approximation of this new model. Second, we provide a novel classification of previously proposed models in the literature and show that they are often not capable of capturing the transient behavior of the network precisely. Numerical results obtained from packet-level simulations demonstrate the accuracy of the proposed model.
|
|
| 4. |
- Dautovic Bergh, Cecilia, 1972-, et al.
(författare)
-
Protein S100B after cardiac surgery: An indicator of long-term anxiety?
- 2007
-
Ingår i: Scandinavian Cardiovascular Journal. - : Informa UK Limited. - 1401-7431 .- 1651-2006. ; 41:2, s. 109-113
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives. The aim of the study was to assess long-term state and trait anxiety in cardiac surgical risk patients. Design. Thirty two patients with serum S100B > 0.3 µg/l 48 hours after cardiac surgery with cardiopulmonary bypass were matched according to age, gender, type, date and length of surgery with 35 operated patients without elevated S100B. They completed Spielberger's Anxiety Inventory (STAI). Results. Patients with elevated S100B reported more state anxiety and trait anxiety. S100B was an independent predictor of both state and trait anxiety when controlling for perioperative variables. Conclusions. Patients with elevated S100B reported more anxiety 3–6 years after cardiac surgery. A postoperative blood sample can identify risk patients and facilitate appropriate follow-up.
|
|
| 5. |
- de Jong, R. S., et al.
(författare)
-
4MOST : Project overview and information for the First Call for Proposals
- 2019
-
Ingår i: The Messenger. - : European Southern Observatory. - 0722-6691. ; 175, s. 3-11
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We introduce the 4-metre Multi-Object Spectroscopic Telescope (4MOST), a new high-multiplex, wide-field spectroscopic survey facility under development for the four-metre-class Visible and Infrared Survey Telescope for Astronomy (VISTA) at Paranal. Its key specifications are: a large field of view (FoV) of 4.2 square degrees and a high multiplex capability, with 1624 fibres feeding two low-resolution spectrographs (R = λ/Δλ ~ 6500), and 812 fibres transferring light to the high-resolution spectrograph (R ~ 20 000). After a description of the instrument and its expected performance, a short overview is given of its operational scheme and planned 4MOST Consortium science; these aspects are covered in more detail in other articles in this edition of The Messenger. Finally, the processes, schedules, and policies concerning the selection of ESO Community Surveys are presented, commencing with a singular opportunity to submit Letters of Intent for Public Surveys during the first five years of 4MOST operations.
|
|
| 6. |
- Jakobsen, Peter, et al.
(författare)
-
Territorial structure: An early Marxist theorisation of geography
- 2022
-
Ingår i: Socio-Spatial Theory in Nordic Geography : Intellectual Histories and Critical Interventions - Intellectual Histories and Critical Interventions. - Cham : Springer International Publishing. - 9783031042331 - 9783031042362 - 9783031042348 ; , s. 51-68
-
Bokkapitel (refereegranskat)abstract
- Radical geography came only patchily to Nordic geography, and the development of theoretical Marxist geography was even sparser. But in the radical geography environment at Copenhagen University, a group of geographers in the 1970s developed a vocal and self-assured Marxist theory, which became known as the territorial-structure approach and drew its inspiration from the work of the GDR geographer Gerhard Schmidt-Renner. In this chapter we present a critical discussion of the territorial-structure approach as an example of an early theorisation of geography from a Marxist perspective. We discuss the central controversies that came to surround the approach, and we discuss the territorial-structure approach as a conscious effort to resist disciplinary specialisation and fragmentation of (human) geography. Our aim is not to resurrect the territorial-structure approach, but rather to investigate this theory as an important step towards socio-spatial theory in Nordic geography.
|
|
| 7. |
- Jönsson, Henrik, et al.
(författare)
-
Controversial significance of early S100B levels after cardiac surgery
- 2004
-
Ingår i: BMC Neurology. - : Springer Science and Business Media LLC. - 1471-2377. ; 4:1
-
Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe brain-derived protein S100B has been shown to be a useful marker of brain injury of different etiologies. Cognitive dysfunction after cardiac surgery using cardiopulmonary bypass has been reported to occur in up to 70% of patients. In this study we tried to evaluate S100B as a marker for cognitive dysfunction after coronary bypass surgery with cardiopulmonary bypass in a model where the inflow of S100B from shed mediastinal blood was corrected for.Methods56 patients scheduled for coronary artery bypass grafting underwent prospective neuropsychological testing. The test scores were standardized and an impairment index was constructed. S100B was sampled at the end of surgery, hourly for the first 6 hours, and then 8, 10, 15, 24 and 48 hours after surgery. None of the patients received autotransfusion.ResultsIn simple linear analysis, no significant relation was found between S100B levels and neuropsychological outcome. In a backwards stepwise regression analysis the three variables, S100B levels at the end of cardiopulmonary bypass, S100B levels 1 hour later and the age of the patients were found to explain part of the neuropsychological deterioration (r = 0.49, p < 0.005).ConclusionsIn this study we found that S100B levels 1 hour after surgery seem to be the most informative. Our attempt to control the increased levels of S100B caused by contamination from the surgical field did not yield different results. We conclude that the clinical value of S100B as a predictive measurement of postoperative cognitive dysfunction after cardiac surgery is limited.
|
|
| 8. |
- Larsen, Henrik Gutzon, et al.
(författare)
-
Sublimated expansionism? Living space ideas in Nordic small-state geopolitics
- 2022
-
Ingår i: Socio-Spatial Theory in Nordic Geography : Intellectual Histories and Critical Interventions - Intellectual Histories and Critical Interventions. - Cham : Springer International Publishing. - 9783031042331 - 9783031042362 - 9783031042348 ; , s. 15-30
-
Bokkapitel (refereegranskat)abstract
- In intellectual histories of geography as well as in international relations, geopolitics is usually the business of great powers, understood as the expansion of hard power through territorial control. However, the existence of a ‘Geopolitik of the weak’ has also been theorised, premised on the ability of smaller states – such as the Nordic countries – to secure their survival through a wider range of policy instruments. In this chapter, we analyse key themes in the work of two Nordic geographical thinkers deeply concerned with the place and status of their home countries in the era of high modernity – Rudolf Kjellén and Gudmund Hatt. Relying upon their scholarly works as well as relevant public debates circa 1905–1945, we trace the ‘small-state geopoliticking’ of Hatt and Kjellén, identifying three key characteristics of their style of small-state geopolitics: (1) determinism is qualified by voluntarism; (2) space is complemented by future; and (3) external expansion is sublimated into internal progress. In its reconceptualisation of living space as primarily concerned with existential survival as premised upon future progress, rather than outward-oriented territorial expansion, small-state geopolitics emerges as a highly situated, somewhat quaint but nonetheless significant element in Nordic theorising of geography.
|
|
| 9. |
- Smiljanic, R., et al.
(författare)
-
The Gaia-ESO Survey: The analysis of high-resolution UVES spectra of FGK-type stars
- 2014
-
Ingår i: Astronomy & Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 570
-
Tidskriftsartikel (refereegranskat)abstract
- Context. The ongoing Gaia-ESO Public Spectroscopic Survey is using FLAMES at the VLT to obtain high-quality medium-resolution Giraffe spectra for about 10(5) stars and high-resolution UVES spectra for about 5000 stars. With UVES, the Survey has already observed 1447 FGK-type stars. Aims. These UVES spectra are analyzed in parallel by several state-of-the-art methodologies. Our aim is to present how these analyses were implemented, to discuss their results, and to describe how a final recommended parameter scale is defined. We also discuss the precision (method-to-method dispersion) and accuracy (biases with respect to the reference values) of the final parameters. These results are part of the Gaia-ESO second internal release and will be part of its first public release of advanced data products. Methods. The final parameter scale is tied to the scale defined by the Gaia benchmark stars, a set of stars with fundamental atmospheric parameters. In addition, a set of open and globular clusters is used to evaluate the physical soundness of the results. Each of the implemented methodologies is judged against the benchmark stars to define weights in three different regions of the parameter space. The final recommended results are the weighted medians of those from the individual methods. Results. The recommended results successfully reproduce the atmospheric parameters of the benchmark stars and the expected T-eff-log g relation of the calibrating clusters. Atmospheric parameters and abundances have been determined for 1301 FGK-type stars observed with UVES. The median of the method-to-method dispersion of the atmospheric parameters is 55K for T-eff, 0.13dex for log g and 0.07 dex for [Fe/H]. Systematic biases are estimated to be between 50-100 K for T-eff, 0.10-0.25 dex for log g and 0.05-0.10 dex for [Fe/H]. Abundances for 24 elements were derived: C, N, O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Mo, Ba, Nd, and Eu. The typical method-to-method dispersion of the abundances varies between 0.10 and 0.20 dex. Conclusions. The Gaia-ESO sample of high-resolution spectra of FGK-type stars will be among the largest of its kind analyzed in a homogeneous way. The extensive list of elemental abundances derived in these stars will enable significant advances in the areas of stellar evolution and Milky Way formation and evolution.
|
|
| 10. |
- Thorsbro, B., et al.
(författare)
-
Evidence against Anomalous Compositions for Giants in the Galactic Nuclear Star Cluster
- 2018
-
Ingår i: Astrophysical Journal. - : Bibliopolis, Edizioni di Filosofia e Scienze. - 0004-637X .- 1538-4357. ; 866:1
-
Tidskriftsartikel (refereegranskat)abstract
- Very strong Sc I lines have recently been found in cool M giants in the Nuclear Star Cluster (NSC) in the Galactic center. Interpreting these as anomalously high scandium abundances in the Galactic center would imply a unique enhancement signature and chemical evolution history for NSCs, and a potential test for models of chemical enrichment in these objects. We present high resolution K-band spectra (NIRSPEC/Keck II) of cool M giants situated in the solar neighborhood and compare them with spectra of M giants in the NSC. We clearly identify strong Sc I lines in our solar neighborhood sample as well as in the NSC sample. The strong Sc I lines in M giants are therefore not unique to stars in the NSC and we argue that the strong lines are a property of the line formation process that currently escapes accurate theoretical modeling. We further conclude that for giant stars with effective temperatures below approximately 3800 K these Sc I lines should not be used for deriving the scandium abundances in any astrophysical environment until we better understand how these lines are formed. We also discuss the lines of vanadium, titanium, and yttrium identified in the spectra, which demonstrate a similar striking increase in strength below 3500 K effective temperature.
|
|
