1,721,079 research outputs found
Accounting for the relationship between money and interest rates
No full textIn time-series from the United States, the relationship between the money to income ratio and the nominal interest rate is a negative and stable one. In Swedish data, there is no such stable relationship. In this paper, we argue that this difference can be explained by the differences in the shock processes that have hit the two countries. Using a dynamic general equilibrium model driven by shock processes estimated to fit the two countries, we find that we can account for the main properties of the data remarkably wel
Methodological aspects on carotid artery intervention
No full textIn Sweden, approximately 25000 patients suffer a cerebral infarction (stroke) annually. Stroke ranks as the third-leading cause of death, and is the leading cause of functional impairment. Carotid artery stenosis accounts for approximately 15% of all strokes and almost all of these are theoretically preventable. There are two conceptually different invasive methods used to treat carotid stenosis: carotid artery stenting (CAS) and carotid endarterectomy (CEA). There are various aspects of these treatments that remain to be evaluated in order to minimize the risks of poor outcome, namely: any differences in short-term and long-term outcomes after CEA or CAS, the potential risks of CAS early after a previous transient ischaemic attack (TIA)/stroke, and the methods to indicate the need of shunting during CEA. Furthermore, since data from randomised controlled trials (RCTs) are often from specialized high volume centres with selected patients, it is important to evaluate population-based results after CAS and CEA.The overall aim of this thesis was to investigate aspects of invasive treatment of carotid artery stenosis, in particular the outcome following endovascular treatment (CAS), and the efficacy of near-infrared spectroscopy in predicting selective shunt use during CEA. The outcome after endovascular treatment was investigated in three cohort studies (study I, II, and III). In study I, we analysed Swedish national short-term results of CAS and CEA and compared a high-volume centre with national results for CAS. In study II we evaluated the procedural risk of CAS, in relation to time from previous TIA /stroke. Study III assessed the long-term population-based outcomes after CAS as compared to CEA. In study IV, a multi-centre diagnostic study, we evaluated the ability of near-infrared spectroscopy (NIRS) to predict cerebral ischaemia during CEA.Study I was a retrospective single-centre review of all consecutive patients treated with CAS at Södersjukhuset between 2004-2011. These results were compared to data from the Swedish national registry for vascular surgery (Swedvasc), where data from all patients treated with CAS or CEA during the same period was extracted. We found that the Swedish national results for CAS were inferior to CEA, but also that it was possible to achieve acceptable results with CAS in a high volume centre. During the study period 464 CAS procedures were performed in Sweden, with 208 of them performed at Södersjukhuset. The stroke and death rate at 30 days among patients in Sweden (Södersjukhuset excluded) was 7.4%. In Södersjukhuset, the stroke and death rate was 2.9%. The results for CAS on a national basis improved over time, the stroke and death rate during the first half of the period was 6.4%, compared to 3.6% in the second part of the study period, which was probably due to the learning curve for the procedure.In study II, all CAS performed for symptomatic carotid stenosis between 2005-2014, were included in a retrospective analysis. Study II revealed that it was safe to perform CAS early (within 1 week), following a TIA/stroke. The stroke and death rate for patient treated within 7 days from neurologic symptom was 4.1%, compared to 6.3% between day 8-14, 4.8% between day 15-28, and 3.6% between days 29-180.The long-term results after CAS in Sweden were examined in study III. In this study, all primary CAS procedures registered in Swedvasc were included (all reoperations were excluded). We compared 409 CAS patients to a control group treated with CEA. The control group was matched with respect to known confounding factors. Postoperative stroke was identified by cross matching the cohort with the In-patient registry. Median follow-up time was 4.1 years, and follow-up data was almost complete. By using Cox regression, we found a substantial (59%) increased risk for late(>30 days) stroke or death for patients treated with CAS compared to CEA. This increased risk was mainly due to an increased risk of ipsilateral stroke during long-term follow-up.In study IV, we have shown that near-infrared spectroscopy has a high sensitivity and acceptable specificity to predict cerebral ischemia during CEA. When a cut-off point of 9% relative decrease in regional SO2 during carotid clamping was chosen, the sensitivity for detecting cerebral ischemia was 95%, and the specificity 81%. This was clearly superior to the conventional and widespread technique of measuring, “stump pressure”.In conclusion, the national population-based results for CAS were inferior to CEA, both short- and long-term. The short-term results after CAS in Sweden have improved over time, and acceptable results can be achieved in high volume centres. If CAS is performed due to symptomatic stenosis it could be performed early after onset of neurologic symptoms. Near-infrared spectroscopy is a reliable method for selective shunting during CEA and superior to stump pressure.List of scientific papersI. Outcome after 7 years of Carotid Artery Stenting and Endarterectomy in Sweden – Single Centre and National Results. David Lindström, Magnus Jonsson, Johan Formgren, Martin Delle, Stefan Rosfors, Peter Gillgren. European journal of vascular and endovascular surgery. 2012;43(5):499-503. https://doi.org/10.1016/j.ejvs.2012.01.024 II. Peri-procedural Risk with Urgent Carotid Artery Stenting: A Population based Swedvasc Study. Magnus Jonsson, Peter Gillgren, Anders Wanhainen, Stefan Acosta, David Lindström. European journal of vascular and endovascular surgery. 2015;49(5):506-12. https://doi.org/10.1016/j.ejvs.2015.01.007 III. Long-Term Outcome After Carotid Artery Stenting - A Population-Based Matched Cohort Study. Magnus Jonsson, David Lindström, Peter Gillgren, Anders Wanhainen, Jonas Malmstedt. Stroke. 2016;47:2083-2089. https://doi.org/10.1161/STROKEAHA.116.013018 IV. Near-infrared Spectroscopy (NIRS) as Predictor for Shunt Need During Carotid Endarterectomy. Magnus Jonsson, David Lindström, Anders Wanhainen, Khatereh Djavani-Gidlund, Peter Gillgren. [Submitted]</p
Investigation of High Pressure Turbine End-Wall Film Cooling Performances under Realistic Inlet Conditions
No full textThe mean value of turbine entry temperature increased to improve efficiency and specific power. Due to the combustor characteristics, thermal and aero-dynamics non-uniformities can be individuated at the turbine inlet section. Then, a further increase in the inlet temperature will generate in the next years harmful conditions also for vane end-walls. In other words, it is necessary to use realistic turbine inlet temperature and velocity profiles to evaluate the effects generated by this design tendency. The objective of the present work is to analyze a cooled high-pressure vane in terms of adiabatic effectiveness and aerodynamic behavior. An end-wall cooling geometry with both fan-shaped and cylindrical holes, tested by EPFL in the frame of the EU funded TATEF2 project, has been chosen. Numerical analysis has been performed by the Energy Engineering Department of the University of Florence. Inlet non-uniformity of total temperature and velocity profile has been considered as representative of realistic situations. According to the distributions of Cd, BR and ηaw, a steady RANS simulation is able to reproduce the experimental data with an error slightly higher that the one of the measurements. Once the inlet T0 profile is imposed, an increase of 100% in the laterally averaged ηaw, generated by the radial T0 distribution can be achieved. The improved performance is visible on the 2D maps, too. The gain in cooling efficiency is limited by the inlet swirl, whose presence modifies the horseshoe vortex development and generates a stronger passage vortex with a detrimental effect for the platform cooling. Therefore, an accurate estimation of the inlet conditions is vital for machine reliability.GT
Supplemental Material - Glycemic control and outcome after carotid intervention in patients with T2D: A Swedish nationwide cohort study
No full textSupplemental Material for Glycemic control and outcome after carotid intervention in patients with T2D: A Swedish nationwide cohort study by Alexander Zabala, Anders Gottsäter, Marcus Lind, Björn Eliasson, Rebecka Bertilsson, Jan Ekelund, Magnus Jonsson, and Thomas Nyström in Diabetes and Vascular Disease Research</p
sj-docx-2-jet-10.1177_15266028211058686 – Supplemental material for Comparison of Early and Mid-Term Outcomes After Fenestrated-Branched Endovascular Aortic Repair in Patients With or Without Prior Infrarenal Repair
No full textSupplemental material, sj-docx-2-jet-10.1177_15266028211058686 for Comparison of Early and Mid-Term Outcomes After Fenestrated-Branched Endovascular Aortic Repair in Patients With or Without Prior Infrarenal Repair by Mario D’Oria, Jacob Budtz-Lilly, David Lindstrom, Goran Lundberg, Magnus Jonsson, Anders Wanhainen, Kevin Mani and Jon Unosson in Journal of Endovascular Therapy</p
sj-docx-1-jet-10.1177_15266028211058686 – Supplemental material for Comparison of Early and Mid-Term Outcomes After Fenestrated-Branched Endovascular Aortic Repair in Patients With or Without Prior Infrarenal Repair
No full textSupplemental material, sj-docx-1-jet-10.1177_15266028211058686 for Comparison of Early and Mid-Term Outcomes After Fenestrated-Branched Endovascular Aortic Repair in Patients With or Without Prior Infrarenal Repair by Mario D’Oria, Jacob Budtz-Lilly, David Lindstrom, Goran Lundberg, Magnus Jonsson, Anders Wanhainen, Kevin Mani and Jon Unosson in Journal of Endovascular Therapy</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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