| 51. |
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| 53. |
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| 54. |
- Pepic, I., et al.
(författare)
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Early detection of sepsis using artificial intelligence : a scoping review protocol
- 2021
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Ingår i: Systematic Reviews. - : Springer Nature. - 2046-4053. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. To decrease the high case fatality rates and morbidity for sepsis and septic shock, there is a need to increase the accuracy of early detection of suspected sepsis in prehospital and emergency department settings. This may be achieved by developing risk prediction decision support systems based on artificial intelligence.Methods: The overall aim of this scoping review is to summarize the literature on existing methods for early detection of sepsis using artificial intelligence. The review will be performed using the framework formulated by Arksey and O’Malley and further developed by Levac and colleagues. To identify primary studies and reviews that are suitable to answer our research questions, a comprehensive literature collection will be compiled by searching several sources. Constrictions regarding time and language will have to be implemented. Therefore, only studies published between 1 January 1990 and 31 December 2020 will be taken into consideration, and foreign language publications will not be considered, i.e., only papers with full text in English will be included. Databases/web search engines that will be used are PubMed, Web of Science Platform, Scopus, IEEE Xplore, Google Scholar, Cochrane Library, and ACM Digital Library. Furthermore, clinical studies that have completed patient recruitment and reported results found in the database ClinicalTrials.gov will be considered. The term artificial intelligence is viewed broadly, and a wide range of machine learning and mathematical models suitable as base for decision support will be evaluated. Two members of the team will test the framework on a sample of included studies to ensure that the coding framework is suitable and can be consistently applied. Analysis of collected data will provide a descriptive summary and thematic analysis. The reported results will convey knowledge about the state of current research and innovation for using artificial intelligence to detect sepsis in early phases of the medical care chain.Ethics and dissemination: The methodology used here is based on the use of publicly available information and does not need ethical approval. It aims at aiding further research towards digital solutions for disease detection and health innovation. Results will be extracted into a review report for submission to a peer-reviewed scientific journal. Results will be shared with relevant local and national authorities and disseminated in additional appropriate formats such as conferences, lectures, and press releases.
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| 55. |
- Rich, Evan A., et al.
(författare)
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The fundamental stellar parameters of FGK stars in the SEEDS survey Norman, OK 73071, USA
- 2017
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 472:2, s. 1736-1752
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Tidskriftsartikel (refereegranskat)abstract
- Large exoplanet surveys have successfully detected thousands of exoplanets to-date. Utilizing these detections and non-detections to constrain our understanding of the formation and evolution of planetary systems also requires a detailed understanding of the basic properties of their host stars. We have determined the basic stellar properties of F, K and G stars in the Strategic Exploration of Exoplanets and Disks with Subaru (SEEDS) survey from Echelle spectra taken at the Apache Point Observatory's 3.5m telescope. Using ROBOSPECT to extract line equivalent widths and TemperatureGravity microtrubulentVelocity ITerations to calculate the fundamental parameters, we have computed T-eff, log(g), v(t), [Fe/H], chromospheric activity and the age for our sample. Our methodology was calibrated against previously published results for a portion of our sample. The distribution of [Fe/H] in our sample is consistent with that typical of the Solar neighbourhood. Additionally, we find the ages of most of our sample are < 500 Myr, but note that we cannot determine robust ages from significantly older stars via chromospheric activity age indicators. The futuremeta-analysis of the frequency ofwide stellar and sub-stellar companions imaged via the SEEDS survey will utilize our results to constrain the occurrence of detected comoving companions with the properties of their host stars.
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| 56. |
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| 57. |
- Toogood, Andy, et al.
(författare)
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Similar Clinical Features Among Patients With Severe Adult Growth Hormone Deficiency Diagnosed With Insulin Tolerance Test Or Arginine Or Glucagon Stimulation Tests
- 2012
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Ingår i: Endocrine Practice. - 1530-891X .- 1934-2403. ; 18:3, s. 325-334
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To determine whether the ITT, arginine (AST) and glucagon stimulation tests (GST) identify patients who have similar features of GH deficiency using a diagnostic threshold of 3 μg/l.Patients and Methods: 5453 tests were available from 4,867 patients registered in the KIMS database (49.9% females, ITT = 3111, AST = 1390, GST = 952). Comparisons were made for GH peak, BMI, lipids, waist circumference, waist:hip ratio and quality of life (QoL-AGHDA questionnaire).Results.There were significant (p<0.0001) intra-individual correlations between the GH peaks for the ITT vs AST (r = 0.655), ITT vs GST (r = 0.445) and AST vs GST (r = 0.632). GH peaks in response to all tests were negatively correlated to the number of additional pituitary hormone deficiencies, and positively correlated to IGF-I SDS. BMI had a negative influence on all three tests.Comparing GHD patients according to the diagnostic test used, most clinical variables did not differ between the groups. The only exceptions showing any difference were BMI being slightly higher in the AST and GST groups, triglyceride levels increased in the GST group, and IGF-I SDS was lower in the ITT and AST than in the GST group. Waist circumference was larger and quality of life was worse in the GST group than in the other groups.Conclusions.This study demonstrates that the ITT, AST and GST produce similar GH peaks, are influenced by similar clinical factors and identify patients with similar features of GH deficiency at a diagnostic threshold of 3 μg/L.
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| 58. |
- Unterkalmsteiner, Michael, et al.
(författare)
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A conceptual framework for SPI evaluation
- 2014
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Ingår i: Journal of Software: Evolution and Process. - : Wiley. - 2047-7473. ; 26:2, s. 251-279
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Tidskriftsartikel (refereegranskat)abstract
- Software Process Improvement (SPI) encompasses the analysis and modification of the processes within software development, aimed at improving key areas that contribute to the organizations’ goals. The task of evaluating whether the selected improvement path meets these goals is challenging. On the basis of the results of a systematic literature review on SPI measurement and evaluation practices, we developed a framework (SPI Measurement and Evaluation Framework (SPI-MEF)) that supports the planning and implementation of SPI evaluations. SPI-MEF guides the practitioner in scoping the evaluation, determining measures, and performing the assessment. SPI-MEF does not assume a specific approach to process improvement and can be integrated in existing measurement programs, refocusing the assessment on evaluating the improvement initiative’s outcome. Sixteen industry and academic experts evaluated the framework’s usability and capability to support practitioners, providing additional insights that were integrated in the application guidelines of the framework.
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| 59. |
- Unterkalmsteiner, Michael, et al.
(författare)
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Evaluation and Measurement of Software Process Improvement : A Systematic Literature Review
- 2012
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Ingår i: IEEE Transactions on Software Engineering. - : IEEE. - 0098-5589 .- 1939-3520. ; 38:2, s. 398-424
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Tidskriftsartikel (refereegranskat)abstract
- Software Process Improvement (SPI) is a systematic approach to increase the efficiency and effectiveness of a software development organization and to enhance software products. OBJECTIVE—This paper aims to identify and characterize evaluation strategies and measurements used to assess the impact of different SPI initiatives. METHOD--The systematic literature review includes 148 papers published between 1991 and 2008. The selected papers were classified according to SPI initiative, applied evaluation strategies and measurement perspectives. Potential confounding factors interfering with the evaluation of the improvement effort were assessed. RESULTS--Seven distinct evaluation strategies were identified, whereas the most common one, "Pre-Post Comparison", was applied in 49% of the inspected papers. Quality was the most measured attribute (62%), followed by Cost (41%) and Schedule (18%). Looking at measurement perspectives, "Project" represents the majority with 66%. CONCLUSION—The evaluation validity of SPI initiatives is challenged by the scarce consideration of potential confounding factors, particularly given that "Pre-Post Comparison" was identified as the most common evaluation strategy, and the inaccurate descriptions of the evaluation context. Measurements to assess the short and mid-term impact of SPI initiatives prevail, whereas long-term measurements in terms of customer satisfaction and return on investment tend to be less used.
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| 60. |
- Vigan, A., et al.
(författare)
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First light of the VLT planet finder SPHERE I. Detection and characterization of the substellar companion GJ 758 B
- 2016
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 587
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Tidskriftsartikel (refereegranskat)abstract
- GJ 758 B is a brown dwarf companion to a nearby (15.76%) solar-type, metal-rich (M/H = +0.2 dex) main-sequence star (G9V) that was discovered with Subaru/HiCIAO in 2009. From previous studies, it has drawn attention as being the coldest (similar to 600 K) companion ever directly imaged around a neighboring star. We present new high-contrast data obtained during the commissioning of the SPHERE instrument at the Very Large Telescope (VLT). The data was obtained in Y-, J-, H-, and K-s-bands with the dual-band imaging (DBI) mode of IRDIS, thus providing a broad coverage of the full near-infrared (near-IR) range at higher contrast and better spectral sampling than previously reported. In this new set of high-quality data, we report the re-detection of the companion, as well as the first detection of a new candidate closer-in to the star. We use the new eight photometric points for an extended comparison of GJ 758 B with empirical objects and four families of atmospheric models. From comparison to empirical object, we estimate a T8 spectral type, but none of the comparison objects can accurately represent the observed near-IR fluxes of GJ 758 B. From comparison to atmospheric models, we attribute a T-eff = 600 +/- 100 K, but we find that no atmospheric model can adequately fit all the fluxes of GJ 758 B. The lack of exploration of metal enrichment in model grids appears as a major limitation that prevents an accurate estimation of the companion physical parameters. The photometry of the new candidate companion is broadly consistent with L-type objects, but a second epoch with improved photometry is necessary to clarify its status. The new astrometry of GJ 758 B shows a significant proper motion since the last epoch. We use this result to improve the determination of the orbital characteristics using two fitting approaches: Least-Squares Monte Carlo and Markov chain Monte Carlo. We confirm the high-eccentricity of the orbit (peak at 0.5), and find a most likely semi-major axis of 46.05 AU. We also use our imaging data, as well as archival radial velocity data, to reject the possibility that this is a false positive effect created by an unseen, closer-in, companion. Finally, we analyze the sensitivity of our data to additional closer-in companions and reject the possibility of other massive brown dwarf companions down to 4-5 AU.
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| 61. |
- Vigan, A., et al.
(författare)
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The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs at wide orbits
- 2017
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 603
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the formation and evolution of giant planets (>= 1 M-Jup) at wide orbital separation (>= 5 AU) is one of the goals of direct imaging. Over the past 15 yr, many surveys have placed strong constraints on the occurrence rate of wide-orbit giants, mostly based on non-detections, but very few have tried to make a direct link with planet formation theories. In the present work, we combine the results of our previously published VLT/NaCo large program with the results of 12 past imaging surveys to constitute a statistical sample of 199 FGK stars within 100 pc, including three stars with sub-stellar companions. Using Monte Carlo simulations and assuming linear flat distributions for the mass and semi-major axis of planets, we estimate the sub-stellar companion frequency to be within 0.75-5.70% at the 68% confidence level (CL) within 20-300 AU and 0.5-75 M-Jup, which is compatible with previously published results. We also compare our results with the predictions of state-of-the-art population synthesis models based on the gravitational instability (GI) formation scenario with and without scattering. We estimate that in both the scattered and non-scattered populations, we would be able to detect more than 30% of companions in the 1-75 M-Jup range (95% CL). With the three sub-stellar detections in our sample, we estimate the fraction of stars that host a planetary system formed by GI to be within 1.0-8.6% (95% CL). We also conclude that even though GI is not common, it predicts a mass distribution of wide-orbit massive companions that is much closer to what is observed than what the core accretion scenario predicts. Finally, we associate the present paper with the release of the Direct Imaging Virtual Archive (DIVA), a public database that aims at gathering the results of past, present, and future direct imaging surveys.
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| 62. |
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| 63. |
- Zurlo, A., et al.
(författare)
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First light of the VLT planet finder SPHERE III. New spectrophotometry and astrometry of the HR 8799 exoplanetary system
- 2016
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 587
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Tidskriftsartikel (refereegranskat)abstract
- Context. The planetary system discovered around the young A-type HR8799 provides a unique laboratory to: a) test planet formation theories; b) probe the diversity of system architectures at these separations, and c) perform comparative (exo)planetology.Aims. We present and exploit new near-infrared images and integral-field spectra of the four gas giants surrounding HR8799 obtained with SPHERE, the new planet finder instrument at the Very Large Telescope, during the commissioning and science verification phase of the instrument (July-December 2014). With these new data, we contribute to completing the spectral energy distribution (SED) of these bodies in the 1.0-2.5 mu m range. We also provide new astrometric data, in particular for planet e, to further constrain the orbits.Methods. We used the infrared dual-band imager and spectrograph (IRDIS) subsystem to obtain pupil-stabilized, dual-band H2H3 (1.593 mu m, 1.667 mu m), K1K2 (2.110 mu m, 2.251 mu m), and broadband J (1.245 mu m) images of the four planets. IRDIS was operated in parallel with the integral field spectrograph (IFS) of SPHERE to collect low-resolution (R similar to 30), near-infrared (0.94-1.64 mu m) spectra of the two innermost planets HR8799 d and e. The data were reduced with dedicated algorithms, such as the Karhunen-Loeve image projection (KLIP), to reveal the planets. We used the so-called negative planets injection technique to extract their photometry, spectra, and measure their positions. We illustrate the astrometric performance of SPHERE through sample orbital fits compatible with SPHERE and literature data.Results. We demonstrated the ability of SPHERE to detect and characterize planets in this kind of systems, providing spectra and photometry of its components. The spectra improve upon the signal-to-noise ratio of previously obtained data and increase the spectral coverage down to the Y band. In addition, we provide the first detection of planet e in the J band. Astrometric positions for planets HR8799 bcde are reported for the epochs of July, August, and December 2014. We measured the photometric values in J, H2H3, K1K2 bands for the four planets with a mean accuracy of 0.13 mag. We found upper limit constraints on the mass of a possible planet f of 3-7 M-Jup. Our new measurements are more consistent with the two inner planets d and e being in a 2d:1e or 3d:2e resonance. The spectra of HR8799 d and e are well matched by those of L6-8 field dwarfs. However, the SEDs of these objects are redder than field L dwarfs longward of 1.6 mu m.
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| 64. |
- Zurlo, A., et al.
(författare)
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Orbital and dynamical analysis of the system around HR 8799 New astrometric epochs from VLT/SPHERE and LBT/LUCI
- 2022
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 666
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Tidskriftsartikel (refereegranskat)abstract
- Context. HR 8799 is a young planetary system composed of four planets and a double debris belt. Being the first multi-planetary system discovered with the direct imaging technique, it has been observed extensively since 1998. This wide baseline of astrometric measurements, counting over 50 observations in 20 years, permits a detailed orbital and dynamical analysis of the system.Aims. To explore the orbital parameters of the planets, their dynamical history, and the planet-to-disk interaction, we made follow-up observations of the system during the VLT/SPHERE guaranteed time observation program. We obtained 21 observations, most of them in favorable conditions. In addition, we observed HR 8799 with the instrument LUCI at the Large Binocular Telescope (LBT).Methods. All the observations were reduced with state-of-the-art algorithms implemented to apply the spectral and angular differential imaging method. We re-reduced the SPHERE data obtained during the commissioning of the instrument and in three open-time programs to have homogeneous astrometry. The precise position of the four planets with respect to the host star was calculated by exploiting the fake negative companions method. We obtained an astrometric precision of the order of 6 mas in the worst case and 1 mas in the best case. To improve the orbital fitting, we also took into account all of the astrometric data available in the literature. From the photometric measurements obtained in different wavelengths, we estimated the masses of the planets following the evolutionary models.Results. We obtained updated parameters for the orbits with the assumption of coplanarity, relatively small eccentricities, and periods very close to the 2:1 resonance. We also refined the dynamical mass of each planet and the parallax of the system (24.49 ± 0.07 mas), which overlap with the recent Gaia eDR3/DR3 estimate. Hydrodynamical simulations suggest that inward migration of the planets caused by the interaction with the disk might be responsible for the planets being locked in resonance. We also conducted detailed N-body simulations indicating possible positions of a putative fifth planet with a mass below the present detection limits of ≃3 MJup.
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