SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Ekberg Peter) "

Sökning: WFRF:(Ekberg Peter)

  • Resultat 1-50 av 101
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Björklund, Patrik, et al. (författare)
  • Västerås slott : Slott och borgar
  • 2000
  • Rapport (populärvet., debatt m.m.)abstract
    • En majoritet av dagens byggnadsuppgifter gäller att hantera det redan byggda. När vi står inför situationen att restaurera en befintlig byggnad är det viktigt att förstå olika tidsperioders stilideal liksom byggnadsteknik och material. Först då kan vi göra en väl avvägd analys, som tar tillvara och utvecklar de kvaliteter som byggnaderna själva besitter. Därför är utbildningen upplagd som ett växelspel mellan föreläsningar, seminarier, exkursioner och en för året vald studieuppgift.Slott och borgar har varit läsårets tema. Vi har valt att arbeta med Västerås och Örebro slott - två ganska bortglömda Vasaslott som är väl värda att lyfta fram. Särskilt har vi studerat de senaste 300 årens förändringar, som inte tidigare ägnats lika stora forskarmöda som medelitden och Vasatiden. I dessa två exempel finns en provkarta på estetiska, praktiska och tekniska ingrepp från Carl Hårlemans tid och fram till idag.Studierna har således omfattat både gestaltning, funktion och byggnadsteknik. Avsikten är att visa på kvaliteter i de omvandlingar och restaureringar som skett, men också att peka på problem och analysera olika möjligheter inför framtiden. Arbetet har skett i samarbete med Statens fastighetsverk och är tänkt att utgöra ett underlag till vårdprogram och framtida restaureringsinsatser. 
  •  
2.
  • Diaz, Sandra, et al. (författare)
  • Hyperpolarized (3)He apparent diffusion coefficient MRI of the lung: Reproducibility and volume dependency in healthy volunteers and patients with emphysema.
  • 2008
  • Ingår i: Journal of Magnetic Resonance Imaging. - : Wiley. - 1522-2586 .- 1053-1807. ; 27, s. 763-770
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE: To measure the apparent diffusion coefficient (ADC) of hyperpolarized (HP) (3)He gas using diffusion weighted MRI in healthy volunteers and patients with emphysema and examine the reproducibility and volume dependency. MATERIALS AND METHODS: A total of eight healthy volunteers and 16 patients with emphysema were examined after inhalation of HP (3)He gas mixed with nitrogen (N(2)) during breathhold starting from functional residual capacity (FRC) in supine position. Coronal diffusion-sensitized MR images were acquired. Each subject was imaged on three separate days over a seven-day period and received two different volumes (6% and 15% of total lung capacity [TLC]) of HP (3)He each day. ADC maps and histograms were calculated. The mean and standard deviation (SD) of the ADC at different days and volumes were compared. RESULTS: The reproducibility of the mean ADC and SD over several days was good in both healthy volunteers and patients (SD range of 0.003-0.013 cm(2)/second and 0.001-0.009 cm(2)/second at 6% and 15% of TLC for healthy volunteers, and a SD range of 0.001-0.041 cm(2)/second and 0.001-0.011 cm(2)/second, respectively, for patients). A minor but significant increase in mean ADC with increased inhaled gas volume was observed in both groups. CONCLUSION: Mean ADC and SD of HP (3)He MRI is reproducible and discriminates well between healthy controls and patients with emphysema at the higher gas volume. This method is robust and may be useful to gain new insights into the pathophysiology and course of emphysema. J. Magn. Reson. Imaging 2008. (c) 2008 Wiley-Liss, Inc.
  •  
3.
  • Diaz, Sandra, et al. (författare)
  • Validity of apparent diffusion coefficient hyperpolarized He-3-MRI using MSCT and pulmonary function tests as references
  • 2009
  • Ingår i: European Journal of Radiology. - : Elsevier BV. - 1872-7727 .- 0720-048X. ; 71:2, s. 257-263
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: To compare apparent diffusion coefficient (ADC) measurements from hyperpolarized (HP) helium (He-3)-magnetic resonance imaging (MRI) with quantitative data from multislice Computed Tomography (CT) (MSCT) of the whole lungs and pulmonary function tests (PFT). Materials and methods: Twenty-seven subjects, 22 with established emphysema and 5 with preclinical emphysema defined by PFT criteria, were examined with Hp He-3-MRI and MSCT. Mean age was 55 (+/- 12) years, 18 female and 9 male. Mean ADC from He-3-MRI was compared with emphysema index (EI), 15th percentile and mean lung density (MLD) values from MSCT. Both mean ADC and MSCT data were compared to PFT, especially percent of predicted diffusing capacity of carbon monoxide (%predicted DLCO), using Pearson's correlation test. Results: Mean ADC and standard deviation values were 0.392 +/- 0.119 cm(2)/s for the established emphysema group and 0.216 +/- 0.046 for the pre-clinical emphysema group. MSCT values for the established emphysema group and pre-clinical emphysema group were: EI (%) 11 +/- 12 and 0.4 +/- 0.6, respectively; 15th percentile (Hounsfield Units (HU)), -956 +/- 25 and -933 +/- 13, respectively and MLD (HU) -877 +/- 20 and -863 +/- 15, respectively. Correlations between mean ADC and El and 15th percentile were both r=0.90 and for MLD r=0.59. There was higher correlation between mean ADC and %predicted DLCO (r=0.90) than between El and %predicted DLCO (r=0.76). Conclusion: Hp He-3-MRI correlates well with density measurements from MSCT and agrees better than MSCT with %predicted DLCO which is the PFT most related to emphysema. (C) 2008 Elsevier Ireland Ltd. All rights reserved.
  •  
4.
  • Sundin, Maria, 1965, et al. (författare)
  • Mars - a target for teachers and science students
  • 2020
  • Ingår i: Contribution to IAU 367S, Education and Heritage in the Era of Big Data in Astronomy, 8-12 December 2020..
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • A case study is here presented of an interdisciplinary course about Mars for teachers and science students. We aim to share the experience of creating an interdisciplinary approach with lecturers spanning physics, geology, radiation physics and philosophy. Issues in ethics, morality, rights and obligations, conflict management and human psychology as well as rocket orbits, fuel economy, radiation hazards and knowledge of the solar system have proven to be a valued and successful initiative for the further training of teachers and science students. The focus of the course is on planning for a journey with humans to the planet Mars. This provides a great opportunity to package complex societal problems in a physics context. The course is offered with a special sustainability content mark. Mankind has always had a strong and dependent relationship with the physical landscape. The land has given us food and shelter but also imposed challenges and disasters. Understanding the physical environment has been crucial for our survival and development. The same will be equally, or more important for Mars where life conditions are much more extreme. We highlight similarities and differences in the geologic processes that have shaped Earth and Mars. What conditions do the future explorers on Mars have to manage? We then enter the modern era and explore the dynamic Martian landscape of today. Also, by learning to read the landscape we may find locations of shelter such as vast systems of lava tubes, or locations of essential resources such as preserved glacial ice etc. A journey to Mars will cause substantially higher personal irradiation than obtained on Earth. The radiation part of the course lectures starts with defining the different radiation types and the biological effects these different types of radiation will cause. Then, the difference between the irradiation on Earth to the elevated irradiation in space and on Mars is described. Thereafter, it is discussed if this elevated radiation burden can cause acute biological effects, e.g. fatigue, vomiting and death, and late biological effects as cancer induction. Last, possible radiation protection strategies are described and discussed. The philosophy of space exploration consists of philosophical approaches to ethics, presently applied to the topic of Mars exploration and colonization, with environmental ethics (anthropocentric vs ecocentric) and value theory at its core. Four main uses of philosophy are distinguished: ethics, aesthetics, cognition and existentialism. Research has shown that visual representation is an important part for students to be able to create a deeper understanding of concepts as well as context about the material that is taught. Interdisciplinary and complex societal problems have also been shown to be important in science teaching. One way for the teacher to develop his/her teaching is to take further education courses in universities whose focus is to seek and discuss the complex societal problems as well as its solutions from a physics and teacher perspective. Future research could be done on the impact of this course on the education in different levels.
  •  
5.
  • Sundin, Maria, 1965, et al. (författare)
  • Mars – a target for teachers and science students
  • 2021
  • Ingår i: Proceedings of the International Astronomical Union, Vol 15, Symposium 367S. - 1743-9213 .- 1743-9221.
  • Konferensbidrag (refereegranskat)abstract
    • An interdisciplinary course about Mars for teachers and science students is presented. The focus of the course is on planning for a journey with humans to the planet Mars. Issues in ethics, morality, rights and obligations, conflict management and human psychology as well as rocket orbits, fuel economy, radiation hazards and knowledge of the solar system are included. Examination of the teacher students include interpretation of the course material for future pedagogical usage.
  •  
6.
  •  
7.
  •  
8.
  • Acosta, Stefan, et al. (författare)
  • Epidemiology, risk and prognostic factors in mesenteric venous thrombosis.
  • 2008
  • Ingår i: British Journal of Surgery. - : Oxford University Press (OUP). - 1365-2168 .- 0007-1323. ; Aug 21, s. 1245-1251
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND:: Epidemiological reports on risk and prognostic factors in patients with mesenteric venous thrombosis (MVT) are scarce. METHODS:: Patients with MVT were identified through the inpatient and autopsy registry between 2000 and 2006 at Malmö University Hospital. RESULTS:: Fifty-one patients had MVT, diagnosed at autopsy in six. The highest incidence (11.3 per 100 000 person-years) was in the age category 70-79 years. Activated protein C resistance was present in 13 of 29 patients tested. D-dimer at admission was raised in all five patients tested. Multidetector row computed tomography (CT) in the portal venous phase was diagnostic in all 20 patients investigated, of whom 19 were managed conservatively. The median length of resected bowel in 12 patients who had surgery was 0.6 (range 0.1-2.2) m. The overall 30-day mortality rate was 20 per cent; intestinal infarction (P = 0.046), treatment on a non-surgical ward (P = 0.001) and CT not done (P = 0.022) were associated with increased mortality. Cancer was independently associated with long-term mortality: hazard ratio 4.03, 95 per cent confidence interval 1.03 to 15.85; P = 0.046. CONCLUSION:: Portal venous phase CT appeared sensitive in diagnosing MVT. As activated protein C resistance was a strong risk factor, lifelong anticoagulation should be considered. Copyright (c) 2008 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.
  •  
9.
  • Andersson, Robin, 1986, et al. (författare)
  • Integrated analysis of dynamic vehicle-track interaction and plasticity induced damage in the presence of squat defects
  • 2015
  • Ingår i: Proceedings of the 10th International International Conference on Contact Mechanics and Wear of Rail/Wheel Systems, Colorado Springs, USA, August-September 2015.
  • Konferensbidrag (refereegranskat)abstract
    • Despite significant efforts, the mechanisms behind the formation of squats – a form of rolling contact fatigue damage – are not fully understood. This study employs numerical simulations to investigate the propensity of squat initiation in the vicinity of small, isolated rail surface irregularities. Time domain dynamic vehicle–track interaction analysis is used to obtain wheel–rail contact stress distributions, which are mapped onto a continuum finite element model that accounts for plastic deformation of the rail material. The evaluated stress and strain fields are quantified using two RCF impact measures: accumulated effective strain and the Jiang-Sehitoglu multiaxial low cycle fatigue parameter. It is shown that the RCF impact increases with increasing size of the surface irregularity and that clustering of irregularities might strongly promote RCF. The friction coefficient is identified as a very influential parameter. Further, the effect of variations in friction along the rail is evaluated. It is shown that a short rail section of low friction results in fairly high RCF impact.
  •  
10.
  • Andersson, Robin, 1986, et al. (författare)
  • Integrated analysis of dynamic vehicle–track interaction and plasticity induced damage in the presence of squat defects
  • 2016
  • Ingår i: Wear. - : Elsevier BV. - 0043-1648. ; 366-367:SI, s. 139-145
  • Tidskriftsartikel (refereegranskat)abstract
    • Despite significant efforts, the mechanisms behind the formation of squats – a form of rolling contact fatigue (RCF) damage – are not fully understood. This study employs numerical simulations to investigate the propensity of squat initiation in the vicinity of small, isolated rail surface irregularities. Time-domain dynamic vehicle–track interaction analysis is used to obtain wheel–rail contact stress distributions, which are mapped onto a continuum finite element model that accounts for plastic deformation of the rail material. The evaluated stress and strain fields are quantified using two RCF impact measures: accumulated effective strain and the Jiang–Sehitoglu multiaxial low cycle fatigue parameter. It is shown that the RCF impact increases with increasing size of the surface irregularity and that clustering of irregularities might strongly promote RCF. The friction coefficient is identified as a very influential parameter and also the effect of variations in friction along the rail is evaluated.
  •  
11.
  • Armand, Michel, et al. (författare)
  • Lithium-ion batteries – Current state of the art and anticipated developments
  • 2020
  • Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 479
  • Tidskriftsartikel (refereegranskat)abstract
    • Lithium-ion batteries are the state-of-the-art electrochemical energy storage technology for mobile electronic devices and electric vehicles. Accordingly, they have attracted a continuously increasing interest in academia and industry, which has led to a steady improvement in energy and power density, while the costs have decreased at even faster pace. Important questions, though, are, to which extent and how (fast) the performance can be further improved, and how the envisioned goal of truly sustainable energy storage can be realized. Herein, we combine a comprehensive review of important findings and developments in this field that have enabled their tremendous success with an overview of very recent trends concerning the active materials for the negative and positive electrode as well as the electrolyte. Moreover, we critically discuss current and anticipated electrode fabrication processes, as well as an essential prerequisite for “greener” batteries – the recycling. In each of these chapters, we eventually summarize important remaining challenges and propose potential directions for further improvement. Finally, we conclude this article with a brief summary of the performance metrics of commercial lithium-ion cells and a few thoughts towards the future development of this technology including several key performance indicators for the mid-term to long-term future.
  •  
12.
  • Aspelin, Peter, et al. (författare)
  • Ultrasound examination of soft tissue injury of the lower limb in athletes
  • 1992
  • Ingår i: The American journal of sports medicine. - : SAGE Publications. - 1552-3365 .- 0363-5465. ; 20:5, s. 601-603
  • Tidskriftsartikel (refereegranskat)abstract
    • We performed ultrasonography on 32 athletes complaining of intense pain in a swollen and tender thigh or calf after a contusion or stretching trauma. The ultrasonogram was used to visualize the presence and size of a suspected hematoma. The findings included the following: 7 patients with a circumscribed, anechoic lesion compatible with a liquefied hematoma; 10 patients with a circumscribed lesion of mixed echogenicity compatible with areas of liquefied hematoma, coagulated blood, and edema; and 15 patients with a diffuse change in echogenicity of the whole muscle. The circumscribed liquefied, and mixed hematoma were more common after contusion trauma, while the diffuse type was more common after injury caused by stretching. Ultrasonography is useful in localizing the hematoma and in characterizing the different types. Differentiation is important in diagnosis and choice of treatment.
  •  
13.
  • Berglund, Jan, et al. (författare)
  • Rapid increase in volume of the remnant after hemithyroidectomy does not correlate with serum concentration of thyroid stimulating hormone
  • 1998
  • Ingår i: European Journal of Surgery. - : Oxford University Press (OUP). - 1102-4151 .- 1741-9271. ; 164:4, s. 257-262
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVE: To study the effect of postoperative thyroxine on the volume of the thyroid remnant after lobectomy for benign nontoxic goitre. DESIGN: Prospective, randomised study. SETTING: University hospital, Sweden. SUBJECTS: 50 consecutive patients who underwent lobectomy for benign non-toxic goitre. INTERVENTIONS: Patients were randomised postoperatively to take thyroxine 0.1 mg or placebo daily. MAIN OUTCOME MEASURES: The median volume of the remaining thyroid lobe measured by ultrasound. Serum concentrations of thyroxine, triiodothyronine (T3) and thyroid stimulating hormone (TSH) were measured preoperatively and 1, 3, 6, 12 months postoperatively. RESULTS: The median volume of the remaining lobe had increased significantly compared with preoperatively by 1 month postoperatively by 30% in the thyroxine group and 25% in the placebo group (p < 0.01). The difference between the groups was not significant. After the first month the volume did not change significantly. In the thyroxine group, the TSH concentration was unchanged and the thyroxine concentration increased significantly throughout the study. In the placebo group there was a significant increase in TSH concentration and a significant decrease in that of thyroxine at all follow-up examinations. CONCLUSIONS: There is a significant increase in the volume of the remaining thyroid 1 month after lobectomy that persisted throughout the first year. Thyroxine given in a dose that kept the serum TSH concentration at the same level as preoperatively did not seem to influence volume changes; consequently we consider that these are caused by factors other than TSH.
  •  
14.
  •  
15.
  • Bruun, Laila, et al. (författare)
  • Rapid elimination by glomerular filtration of free prostate specific antigen and human kallikrein 2 after renal transplantation.
  • 2004
  • Ingår i: Journal of Urology. - : Ovid Technologies (Wolters Kluwer Health). - 1527-3792 .- 0022-5347. ; 171:4, s. 1432-1435
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE: The low molecular mass and short half-life of free (f) prostate specific antigen (PSA) implies elimination from blood by glomerular filtration. In addition, patients with terminal renal failure have increased fPSA in serum but there have been sparse data reported on the rates and pathways of elimination of PSA complexes and human kallikrein 2 (hK2). We studied glomerular filtration dependent elimination of fPSA and hK2 in patients with renal insufficiency undergoing successful renal transplantation.MATERIALS AND METHODS: We studied 14 patients with immediate onset of renal function after renal transplantation. Blood samples were obtained before and at regular intervals up to 160 hours after transplanted kidney reperfusion. Measurements of fPSA, total PSA and hK2 were performed with immunofluorometric assays and complexed PSA was determined by a chemiluminiscence assay. Glomerular filtration rates were monitored by analyzing serum creatinine and cystatin C. NONMEM, a multivariate pharmacokinetic approach, was used to determine the elimination rates of fPSA and hK2 after renal transplantation.RESULTS: Serum fPSA and hK2 but not PSA complexes, decreased rapidly after renal transplantation. Significant reductions in fPSA and hK2 were observed after only 16 and 8 hours, respectively. fPSA and hK2 showed similar elimination patterns, decreasing to 42% and 44% of their original levels compared to cystatin C, which was at 44% after 160 hours. The median half-lives of fPSA and hK2 were 17.4 and 11.5 hours, respectively.CONCLUSIONS: These results verify the hypothesis that fPSA and hK2 are eliminated from the blood circulation by glomerular filtration and severe renal failure influences the levels of the 2 proteins in serum.
  •  
16.
  • Daemi, Bita, et al. (författare)
  • Advanced image analysis verifies geometry performance of micro-milling systems
  • 2017
  • Ingår i: Applied Optics. - : OPTICAL SOC AMER. - 1559-128X .- 2155-3165. ; 56:10, s. 2912-2921
  • Tidskriftsartikel (refereegranskat)abstract
    • Accurate dimensional measurement of micro-milled items is a challenge and machine specifications do not include operational parameters in the workshop. Therefore, a verification test that shows the machine's overall geometrical performance over its working area would help machine users in the assessment and adjustment of their equipment. In this study, we present an optical technique capable of finding micro-milled features at submicron uncertainty over working areas > 10 cm(2). The technique relies on an ultra-precision measurement microscope combined with advanced image analysis to get the center of gravity of milled cross-shaped features at subpixel levels. Special algorithms had to be developed to handle the disturbing influence of burr and milling marks. The results show repeatability, reproducibility, and axis straightness for three micro-milling facilities and also discovered an unknown 2 mu m amplitude undulation in one of them.
  •  
17.
  • Daemi, Bita, 1982- (författare)
  • Enhanced image analysis, a tool for precision metrology in the micro and macro world
  • 2017
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The need for high speed and cost efficient inspection in manufacturing lineshas led to a vast usage of camera-based vision systems. The performance ofthese systems is sufficient to determine shape and size, but hardly to an accuracylevel comparable with traditional metrology tools. To achieve highprecision shape/position/defect measurements, the camera techniques haveto be combined with high performance image metrology techniques whichare developed and adapted to the manufactured components. The focus ofthis thesis is the application of enhanced image analysis as a tool for highprecision metrology. Dedicated algorithms have been developed, tested andevaluated in three practical cases ranging from micro manufacturing at submicronprecision to meter sized aerospace components with precision requirementsin the 10 μm range.The latter measurement challenge was solved by low cost standard consumerproducts, i.e. digital cameras in a stereo configuration and structured lightfrom a gobo-projector. Combined with high-precision image analysis and anew approach in camera calibration and 3D reconstruction for precise 3Dshape measurement of meter sized surfaces, the achievement was fulfilledand verified by two conventional measurement systems; a high precisioncoordinate measurement machine and a laser scanner.The sub-micron challenge was the implementation of image metrology forverification of micro manufacturing installations within a joint Europeaninfrastructure network, EUMINAfab. The results were an unpleasant surprisefor some of the participating laboratories, but became a big step forwardto improve the dimensional accuracy of the investigated laser micromachining, micro milling and micro-printing systems, since the accuracy ofthese techniques are very difficult to assess.The third high precision metrology challenge was the measurement of longrange,low-amplitude topographic structures on specular (shiny) aerodynamicsurfaces. In this case Fringe Reflection Technique (FRT) was appliedand image analysis algorithms were used to evaluate the fringe deformationas a measure of the surface slopes to obtain high resolution data. The resultwas compared with an interferometric analysis showing height deviation inthe range of tens of micrometers over a lateral extension of several cm.
  •  
18.
  • Daemi, Bita, 1982-, et al. (författare)
  • Lateral performance evaluation of laser micromachining by highprecision optical metrology and image analysis
  • 2017
  • Ingår i: Precision engineering. - : Elsevier. - 0141-6359 .- 1873-2372.
  • Tidskriftsartikel (refereegranskat)abstract
    • Today several techniques are available for micro-manufacturing. Yet, it is difficult to assess the precisionand lateral X,Y accuracy of these techniques. The available accuracy information is usually based on spec-ifications given by machine suppliers. This information is based on in-house laboratory tests performedby dedicated machine operators and within an adapted environment. In practice, the accuracy is likelyto vary due to environmental conditions, materials and operator skills. In order to check the specifica-tions in realistic environments the EUMINAfab infrastructure consortium initiated a set of independenthigh precision onsite verification tests on different laser micromachining installations. In addition toproviding performance verification, it gave the participating partners real capability information of theirequipment and possibilities to improve machining performance to a higher level. In this study a compre-hensive verification test was designed and carried out by using a high precision metrology method for 2Dmeasurements based on subpixel resolution image analysis. This methodology improved our knowledgeof the capabilities of three laser micromachining installations, and showed that specifications at singlemicron levels are hard to obtain.
  •  
19.
  • Daemi, Bita, 1982-, et al. (författare)
  • Performance Evaluation of Micro Milling Installations
  • 2013
  • Ingår i: Proceedings of the 10th International Conference on Multi-Material Micro Manufacture. - Singapore : Research Publishing Services. - 9789810772475 - 9810772475 ; , s. 213-216
  • Konferensbidrag (refereegranskat)abstract
    • Micro manufacturing has developed into many areas over the past decade. Several manufacturing technologies are available but the precision and accuracy of the techniques are still difficult to get access to. Typically the capability information of micro milling equipment is based on specifications given by the machine deliverers. The specified high accuracy is likely to be altered in practice because of environmental conditions and operator skills. So in practice the absolute performances of micro milling/machining equipment may be far off from their listed specifications. When forming the EUMINAfab infrastructure consortium it was decided that independent high precision verification testsshould be made on different installations to help the micro-manufacturers to get the real capability information of their equipment and be able to improve performance to a higher EUMINAfab level. In this study a comprehensive verification test was designed and carried out by using an ultra-precision metrology method for 2D measurements in order to establish more knowledge about the capabilities of micro milling equipment. The measurement results show the machine’s X,Y positioning accuracy, pseudo-repeatability, reproducibility and axis straightness of two different micro milling installations.
  •  
20.
  • Diaz, Sandra, et al. (författare)
  • Progression of Emphysema in a 12-month Hyperpolarized (3)He-MRI Study Lacunarity Analysis Provided a More Sensitive Measure than Standard ADC Analysis(1).
  • 2009
  • Ingår i: Academic Radiology. - : Elsevier BV. - 1878-4046 .- 1076-6332. ; 16:6, s. 700-707
  • Tidskriftsartikel (refereegranskat)abstract
    • RATIONALE AND OBJECTIVES: Inhaled hyperpolarized (3)He magnetic resonance (MR) imaging has been used to measure alveolar size in patients with emphysema. The aim of this study was to test the hypothesis that (3)He MR images could be used to develop a biomarker of emphysema progression. MATERIALS AND METHODS: Twelve healthy controls and 18 patients with emphysema (eight current smokers, 10 ex-smokers) were imaged at baseline and 6 and 12 months. An additional nine subjects with alpha-1 antitrypsin deficiency (four with emphysema, six without symptoms) were also imaged at baseline and at 6 months. Each subject was imaged at two lung volumes: functional residual capacity (FRC) and FRC plus 15% of total lung capacity. Means and standard deviations of apparent diffusion coefficients (ADCs) were calculated from coronal images of the entire lung and correlated with pulmonary function test results. The lacunarity hypothesis was tested and calculated from the data using a range of 2x2 x 2 to 6x6 x 6 voxels, and the average was calculated. RESULTS: There was no change in the mean ADC at either lung volume in any subject over the 6- or 12-month period. FRC and residual volume increased over the 12 months, suggesting air trapping. The lacunarity of images collected at FRC increased at 6 and 12 months in smokers only (P=.063 and P=.023, respectively). CONCLUSIONS: The mean ADC calculated from MR images of the lungs with helium was not sufficiently sensitive to detect changes over a 12-month period. However, lacunarity captured more of the spatial information in the images and detected emphysema progress in the smokers.
  •  
21.
  • dos Santos, Klinsmann Carolo, et al. (författare)
  • The impact of macronutrient composition on metabolic regulation : An Islet-Centric view
  • 2022
  • Ingår i: Acta Physiologica. - : Wiley. - 1748-1708 .- 1748-1716. ; 236:4
  • Tidskriftsartikel (refereegranskat)abstract
    • Aim: The influence of dietary carbohydrates and fats on weight gain is inconclusively understood. We studied the acute impact of these nutrients on the overall metabolic state utilizing the insulin:glucagon ratio (IGR). Methods: Following in vitro glucose and palmitate treatment, insulin and glucagon secretion from islets isolated from C57Bl/6J mice was measured. Our human in vivo study included 21 normoglycaemia (mean age 51.9 ± 16.5 years, BMI 23.9 ± 3.5 kg/m2, and HbA1c 36.9 ± 3.3 mmol/mol) and 20 type 2 diabetes (T2D) diagnosed individuals (duration 12 ± 7 years, mean age 63.6 ± 4.5 years, BMI 29.1 ± 2.4 kg/m2, and HbA1c 52.3 ± 9.5 mmol/mol). Individuals consumed a carbohydrate-rich or fat-rich meal (600 kcal) in a cross-over design. Plasma insulin and glucagon levels were measured at −30, −5, and 0 min, and every 30 min until 240 min after meal ingestion. Results: The IGR measured from mouse islets was determined solely by glucose levels. The palmitate-stimulated hormone secretion was largely glucose independent in the analysed mouse islets. The acute meal tolerance test demonstrated that insulin and glucagon secretion is dependent on glycaemic status and meal composition, whereas the IGR was dependent upon meal composition. The relative reduction in IGR elicited by the fat-rich meal was more pronounced in obese individuals. This effect was blunted in T2D individuals with elevated HbA1c levels. Conclusion: The metabolic state in normoglycaemic individuals and T2D-diagnosed individuals is regulated by glucose. We demonstrate that consumption of a low carbohydrate diet, eliciting a catabolic state, may be beneficial for weight loss, particularly in obese individuals.
  •  
22.
  • Dreja, Julia, et al. (författare)
  • Volumetric analysis of small bowel motility in an unselected cohort of patients with Crohn’s disease
  • 2020
  • Ingår i: Neurogastroenterology and Motility. - : Wiley. - 1350-1925 .- 1365-2982. ; 32:10
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Quantified terminal ileal motility during magnetic resonance enterography (MRE) has been suggested to be used as a biomarker of Crohn's disease (CD). The aim of the present study was to evaluate this method in clinical practice. Methods: Healthy volunteers and all consecutive patients referred to MRE during a 2-year period were asked to participate and complete the Irritable Bowel Syndrome-Symptom Severity Scale (IBS-SSS) to assess gastrointestinal symptoms. Medical records were scrutinized, and motility indices (MIs) were calculated from MR images. Key Results: Twenty-two healthy controls and 134 examinations with CD were included (inclusion rate: 76.3%). Patients with CD had increased mural thickness of the terminal ileum, increased fecal calprotectin, and more symptoms than controls. Patients with active CD had increased mural thickness of ileum and terminal ileum, higher MR activity indices, and signs of inflammation in laboratory analyses, but similar symptoms, compared with inactive disease. After exclusion of sole colon disease (n = 13), MI inversely correlated with mural thickness in terminal ileum, and MI was lower in active disease versus controls in ileum (P =.019) and terminal ileum (P =.005), and versus inactive disease in terminal ileum (P =.044). The area under the curve of MI in terminal ileum was 0.736 for active CD against healthy controls (P =.002) and 0.682 for active against inactive CD (P =.001). MIs were similar in controls and inactive CD. Conclusions and Interferences: MI reflects inflammatory activity in the intestine. Alterations in MI did not explain symptomatology in inactive CD, without measurable inflammatory parameters in morphology or laboratory analyses.
  •  
23.
  • Ekberg, EwaCarin, et al. (författare)
  • Diagnostic Criteria for Temporomandibular Disorders - INfORM recommendations : Comprehensive and short-form adaptations for adolescents.
  • 2023
  • Ingår i: Journal of Oral Rehabilitation. - : John Wiley & Sons. - 1365-2842. ; 50:11, s. 1167-1180
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: The Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) for use in adults is in use worldwide. Until now, no version of this instrument for use in adolescents has been proposed.OBJECTIVE: To present comprehensive and short-form adaptations of the adult version of DC/TMD that are appropriate for use with adolescents in clinical and research settings.METHODS: International experts in TMDs and experts in pain psychology participated in a Delphi process to identify ways of adapting the DC/TMD protocol for physical and psychosocial assessment of adolescents.RESULTS: The proposed adaptation defines adolescence as ages 10-19 years. Changes in the physical diagnosis (Axis I) include (i) adapting the language of the Demographics and the Symptom Questionnaires to be developmentally appropriate for adolescents, (ii) adding two general health questionnaires, one for the adolescent patient and one for their caregivers, and (iii) replacing the TMD Pain Screener with the 3Q/TMD questionnaire. Changes in the psychosocial assessment (Axis II) include (i) adapting the language of the Graded Chronic Pain Scale to be developmentally appropriate for adolescents, (ii) adding anxiety and depression assessment that have been validated for adolescents, and (iii) adding three constructs (stress, catastrophizing and sleep disorders) to assess psychosocial functioning in adolescents.CONCLUSION: The recommended DC/TMD, including Axis I and Axis II for adolescents, is appropriate to use in clinical and research settings. This adapted first version for adolescents includes changes in Axis I and Axis II requiring reliability and validity testing in international settings. Official translations of the comprehensive and short-form to different languages according to INfORM requirements will enable a worldwide dissemination and implementation.
  •  
24.
  • Ekberg, Kerstin, et al. (författare)
  • New Business Structures Creating Organizational Opportunities and Challenges for Work Disability Prevention.
  • 2016
  • Ingår i: Journal of occupational rehabilitation. - : Springer. - 1053-0487 .- 1573-3688. ; 26:4, s. 480-489
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose Flexible work arrangements are growing in order to develop resource-efficient production and because of advanced technologies, new societal values, changing demographics, and globalization. The article aims to illustrate the emerging challenges and opportunities for work disability prevention efforts among workers in alternate work arrangements. Methods The authors participated in a year-long collaboration that ultimately led to an invited 3-day conference, "Improving Research of Employer Practices to Prevent Disability," held October 14-16, 2015, in Hopkinton, Massachusetts, USA. The collaboration included a topical review of the literature, group conference calls to identify key areas and challenges, drafting of initial documents, review of industry publications, and a conference presentation that included feedback from peer researchers and a roundtable discussion with experts having direct employer experience. Results Both worker and employer perspectives were considered, and four common alternate work arrangements were identified: (a) temporary and contingent employment; (b) small workplaces; (c) virtual work/telework; and (d) lone workers. There was sparse available research of return-to-work (RTW) and workplace disability management strategies with regard to alternate work patterns. Limited research findings and a review of the grey literature suggested that regulations and guidelines concerning disabled workers are often ambiguous, leading to unsatisfactory protection. At the workplace level, there was a lack of research evidence on how flexible work arrangements could be handled or leveraged to support RTW and prevent disability. Potential negative consequences of this lack of organizational guidance and information are higher costs for employers and insurers and feelings of job insecurity, lack of social support and integration, or work intensification for disabled workers. Conclusions Future studies of RTW and workplace disability prevention strategies should be designed to reflect the multiple work patterns that currently exist across many working populations, and in particular, flexible work arrangements should be explored in more detail as a possible mechanism for preventing disability. Labor laws and policies need to be developed to fit flexible work arrangements.
  •  
25.
  • Ekberg, Lars Peter, 1955- (författare)
  • Development of ultra-precision tools for metrology and lithography of large area photomasks and high definition displays
  • 2013
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Large area flat displays are nowadays considered being a commodity. After the era of bulky CRT TV technology, LCD and OLED have taken over as the most prevalent technologies for high quality image display devices. An important factor underlying the success of these technologies has been the development of high performance photomask writers in combination with a precise photomask process. Photomask manufacturing can be regarded as an art, highly dependent on qualified and skilled workers in a few companies located in Asia. The manufacturing yield in the photomask process depends to a great extent on several steps of measurements and inspections. Metrology, which is the focus of this thesis, is the science of measurement and is a prerequisite for maintaining high quality in all manufacturing processes. The details and challenges of performing critical measurements over large area photomasks of square meter sizes will be discussed. In particular the development of methods and algorithms related to the metrology system MMS15000, the world standard for large area photomask metrology today, will be presented.The most important quality of a metrology system is repeatability. Achieving good repeatability requires a stable environment, carefully selected materials, sophisticated mechanical solutions, precise optics and capable software. Attributes of the air including humidity, CO2 level, pressure and turbulence are other factors that can impact repeatability and accuracy if not handled properly. Besides the former qualities, there is also the behavior of the photomask itself that needs to be carefully handled in order to achieve a good correspondence to the Cartesian coordinate system. An uncertainty specification below 100 nm (3σ) over an area measured in square meters cannot be fulfilled unless special care is taken to compensate for gravity-induced errors from the photomask itself when it is resting on the metrology tool stage. Calibration is therefore a considerable challenge over these large areas. A novel method for self-calibration will be presented and discussed in the thesis. This is a general method that has proven to be highly robust even in cases when the self-calibration problem is close to being underdetermined.A random sampling method based on massive averaging in the time domain will be presented as the solution for achieving precise spatial measurements of the photomask patterns. This method has been used for detection of the position of chrome or glass edges on the photomask with a repeatability of 1.5 nm (3σ), using a measurement time of 250 ms. The method has also been used for verification of large area measurement repeatability of approximately 10 nm (3σ) when measuring several hundred measurement marks covering an area of 0.8 x 0.8 m2.The measurement of linewidths, referred to in the photomask industry as critical dimension (CD) measurements, is another important task for the MMS15000 system. A threshold-based inverse convolution method will be presented that enhances resolution down to 0.5 µm without requiring a change to the numerical aperture of the system.As already mentioned, metrology is very important for maintaining high quality in a manufacturing environment. In the mask manufacturing industry in particular, the cost of poor quality (CoPQ) is extremely high. Besides the high materials cost, there are also the stringent requirements placed on CD and mask overlay, along with the need for zero defects that make the photomask industry unique. This topic is discussed further, and is shown to be a strong motivation for the development of the ultra-precision metrology built into the MMS15000 system.
  •  
26.
  •  
27.
  • Ekberg, Marie, et al. (författare)
  • Hospital admission rates among men and women with symptoms of chronic bronchitis and airflow limitation corresponding to the GOLD stages of chronic obstructive pulmonary disease - A population-based study
  • 2008
  • Ingår i: Respiratory Medicine. - : Elsevier BV. - 1532-3064 .- 0954-6111. ; 102:1, s. 109-120
  • Tidskriftsartikel (refereegranskat)abstract
    • Chronic obstructive pulmonary disease is a major cause of increased morbidity and mortality. The aim of this study was to investigate hospital admission rates among individuals with symptoms of chronic bronchitis and among those with airflow limitation corresponding to GOLD stages 1-4. Method: Between 1974 and 1992, 22 044 middle-aged individuals participated in a health screening, which included spirometry (without broncho-dilation), as well as recording of respiratory symptoms and smoking habits. Information on hospital admissions until 31 December 2002 was obtained from local and national registers. The hospital admission rates due to all causes, obstructive Lung disease and cardiovascular disease were analysed among individuals with symptoms of chronic bronchitis and among those with airflow limitation corresponding to GOLD stages 1-4 using ordinal regression with adjustment for age and with individuals with normal lung function and without symptoms of chronic bronchitis as reference group. Results: Symptoms of chronic bronchitis and GOLD stages 1-4 showed increased hospital admission rates (hospital admission rates due to obstructive lung disease excluded) among smokers of both genders. Furthermore, symptoms of chronic bronchitis showed increased hospital admission rates due to obstructive lung disease among smoking women. There were also increased hospital admission rates due to obstructive lung disease among smokers of GOLD stages 1-4 and increased hospital admission rates due to cardiovascular disease among female smokers of GOLD stage 2. Conclusion: Among smokers, symptoms of chronic bronchitis as well airflow limitation corresponding to GOLD stages 1-4 conveyed a substantial morbidity with increased hospital admission rates due to all causes. The burden of disease is most likely underestimated among individuals with symptoms of chronic bronchitis and chronic obstructive pulmonary disease.
  •  
28.
  • Ekberg, Marie, et al. (författare)
  • Mortality in GOLD stages of COPD and its dependence on symptoms of chronic bronchitis
  • 2005
  • Ingår i: Respiratory Research. - : Springer Science and Business Media LLC. - 1465-9921 .- 1465-993X. ; 6, s. 98-106
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: The GOLD classification of COPD severity introduces a stage 0 ( at risk) comprising individuals with productive cough and normal lung function. The aims of this study were to investigate total mortality risks in GOLD stages 0 - 4 with special focus on stage 0, and furthermore to assess the influence of symptoms of chronic bronchitis on mortality risks in GOLD stages 1 - 4. Method: Between 1974 and 1992, a total of 22 044 middle-aged individuals participated in a health screening, which included a spirometry as well as recording of respiratory symptoms and smoking habits. Individuals with comorbidity at baseline ( diabetes, stroke, cancer, angina pectoris, or heart infarction) were excluded from the analyses. Hazard ratios (HR 95% CI) of total mortality were analyzed in GOLD stages 0 - 4 with individuals with normal lung function and without symptoms of chronic bronchitis as a reference group. HR: s in smoking individuals with symptoms of chronic bronchitis within the stages 1 - 4 were calculated with individuals with the same GOLD stage but without symptoms of chronic bronchitis as reference. Results: The number of deaths was 3674 for men and 832 for women based on 352 324 and 150 050 person-years respectively. The proportion of smokers among men was 50% and among women 40%. Self reported comorbidity was present in 4.6% of the men and 6.6% of the women. Among smoking men, Stage 0 was associated with an increased mortality risk, HR; 1.65 ( 1.32 - 2.08), of similar magnitude as in stage 2, HR; 1.41 ( 1.31 - 1.70). The hazard ratio in stage 0 was significantly higher than in stage 1 HR; 1.13 ( 0.98 - 1.29). Among male smokers with stage 1; HR: 2.04 ( 1.34 - 3.11), and among female smokers with stage 2 disease; HR: 3.16 ( 1.38 - 7.23), increased HR: s were found in individuals with symptoms of chronic bronchitis as compared to those without symptoms of chronic bronchitis. Conclusion: Symptoms fulfilling the definition of chronic bronchitis were associated with an increased mortality risk among male smokers with normal pulmonary function ( stage 0) and also with an increased risk of death among smoking individuals with mild to moderate COPD ( stage 1 and 2).
  •  
29.
  • Ekberg, Marie, et al. (författare)
  • Socio-economic status and lung cancer risk including histologic subtyping-A longitudinal study.
  • 2006
  • Ingår i: Lung Cancer. - : Elsevier BV. - 1872-8332 .- 0169-5002. ; 51:1, s. 21-29
  • Tidskriftsartikel (refereegranskat)abstract
    • We investigated prospectively the risk of lung cancer in relation to socioeconomic status (SES) in 22387 middle-aged individuals who attended a screening program in the city of Malmo, Sweden between 1974 and 1992. We also examined the relationship between SES and histologic subtype in smokers. By 2003, a total of 550 lung cancer cases had been identified. Relative risks (RR) were calculated with adjustment for age, current smoking, inhalation habits and marital status at baseline in the low SES group compared to high SES group. Among smokers, the RR (95% confidence interval (Cl)) for lung cancer in the tow SES group of men was 1.39 (1.11-1.73), and women 1.56 (1.04-2.34). Also among smokers, low SES was associated with an increased risk of squamous cell carcinoma in men; RR 1.89 (1.16-2.81) and women; RR 7.10 (1.63-30.86), and with an increased risk of mesothelioma in men RR 9.97 (1.29-76.96). We conclude that Low SES groups run an increased risk of lung cancer despite accounting for smoking habits. Furthermore, tow SES was positively associated with squamous cell carcinoma and mesothelioma. Our results suggest that the association between low SES and lung cancer could be mediated by unaccounted for smoking exposure, Lifestyle or occupational hazards. (C) 2005 Elsevier Ireland Ltd. All rights reserved.
  •  
30.
  • Ekberg, N. R., et al. (författare)
  • Smart Pen Exposes Missed Basal Insulin Injections and Reveals the Impact on Glycemic Control in Adults With Type 1 Diabetes
  • 2024
  • Ingår i: Journal of Diabetes Science and Technology. - : SAGE Publications. - 1932-2968. ; 18:1, s. 66-73
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Adherence to basal insulin injections and the effects of missed basal insulin injections in adults with type 1 diabetes (T1D) were investigated using data from continuous glucose monitoring (CGM) and smart insulin pen devices in a real-world study. Methods: This was a post hoc analysis of a prospective, real-world study conducted in Sweden. Adults with T1D who were using CGM received a smart insulin pen device (NovoPen 6) for insulin injections. Missed basal insulin doses (≥40 hours between doses) were evaluated over 14-day periods, and the probability of missing basal insulin doses was estimated. Associations between missed basal insulin doses and glycemic outcomes were also explored. Results: Thirty-two patients with 4410 acceptable CGM days (315 14-day periods) were included. The number of missed basal insulin doses ranged from 0 to 4 over 315 14-day periods. The estimated probability of missing at least one basal insulin dose over any given 14-day period was 22% (95% confidence interval: 10%-40%). Missed basal insulin doses were significantly associated with higher mean glycemic levels, higher glucose management indicator, and lower time in range (70-180 mg/dL [3.9-10.0 mmol/L]). Similar results were observed when adjusted for missed bolus insulin doses; age and sex had no statistically significant effect on any glycemic parameter. Conclusions: This is the first study, based on accurate real-world injection data, to demonstrate the challenge of adherence to basal insulin injections in patients with T1D, and document that just one missed basal injection per week can result in clinically significant changes in glycemic control. © 2022 Diabetes Technology Society.
  •  
31.
  • Ekberg, Olle, et al. (författare)
  • In memoriam Prof. Erik Boijsen
  • 2018
  • Ingår i: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 28:4, s. 1788-1789
  • Tidskriftsartikel (refereegranskat)
  •  
32.
  •  
33.
  • Ekberg, Peter, et al. (författare)
  • 3D precision measurements of meter sized surfaces using low cost illumination and camera techniques
  • 2017
  • Ingår i: Measurement science and technology. - : Institute of Physics Publishing (IOPP). - 0957-0233 .- 1361-6501. ; 28:4
  • Tidskriftsartikel (refereegranskat)abstract
    • Using dedicated stereo camera systems and structured light is a well-known method for measuring the 3D shape of large surfaces. However the problem is not trivial when high accuracy, in the range of few tens of microns, is needed. Many error sources need to be handled carefully in order to obtain high quality results. In this study, we present a measurement method based on low-cost camera and illumination solutions combined with high-precision image analysis and a new approach in camera calibration and 3D reconstruction. The setup consists of two ordinary digital cameras and a Gobo projector as a structured light source. A matrix of dots is projected onto the target area. The two cameras capture the images of the projected pattern on the object. The images are processed by advanced subpixel resolution algorithms prior to the application of the 3D reconstruction technique. The strength of the method lays in a different approach for calibration, 3D reconstruction, and high-precision image analysis algorithms. Using a 10 mm pitch pattern of the light dots, the method is capable of reconstructing the 3D shape of surfaces. The precision (1 sigma repeatability) in the measurements is < 10 mu m over a volume of 60 x 50 x 10 cm(3) at a hardware cost of similar to 2% of available advanced measurement techniques. The expanded uncertainty (95% confidence level) is estimated to be 83 mu m, with the largest uncertainty contribution coming from the absolute length of the metal ruler used as reference.
  •  
34.
  • Ekberg, Peter, et al. (författare)
  • A Large-area ultra-precision 2D geometrical measurement technique based on statistical random phase detection
  • 2012
  • Ingår i: Measurement science and technology. - : Institute of Physics Publishing (IOPP). - 0957-0233 .- 1361-6501. ; 23:3
  • Tidskriftsartikel (refereegranskat)abstract
    • The manufacturing of high-quality chrome masks used in the display industry for the manufacturing of liquid crystals, organic light emission diodes and other display devices would not be possible without high-precision large-area metrology. In contrast to the semiconductor industry where 6' masks are most common, the quartz glass masks for the manufacturing of large area TVs can have sizes of up to 1.6 x 1.8 m(2). Besides the large area, there are demands of sub-micrometer accuracy in 'registration', i.e. absolute dimensional measurements and nanometer requirements for 'overlay', i.e. repeatability. The technique for making such precise measurements on large masks is one of the most challenging tasks in dimensional metrology today. This paper presents a new approach to two-dimensional (2D) ultra-precision measurements based on random sampling. The technique was recently presented for ultra-precise one-dimensional (1D) measurement. The 1D method relies on timing the scanning of a focused laser beam 200 mu m in the Y-direction from an interferometrically determined reference position. This microsweep is controlled by an acousto-optical deflector. By letting the microsweep scan from random X-positions, we can build XY-recordings through a time-to-space conversion that gives very precise maps of the feature edges of the masks. The method differs a lot from ordinary image processing methods using CCD or CMOS sensors for capturing images in the spatial domain. We use events grabbed by a single detector in the time domain in both the X-and Y-directions. After a simple scaling, we get precise and repeatable spatial information. Thanks to the extremely linear microsweep and its precise power control, spatial and intensity distortions, common in ordinary image processing systems using 2D optics and 2D sensors, can be practically eliminated. Our 2D method has proved to give a standard deviation in repeatability of less than 4 nm (1 sigma) in both the X-and Y-directions over an area of approximately 0.8 x 0.8 m(2). Only feature edges are recorded, so all irrelevant information in areas containing constant intensity are filtered out already by the hardware. This relaxes the demands and complexity of the data channel dramatically compared to conventional imaging systems.
  •  
35.
  • Ekberg, Peter, et al. (författare)
  • A new 2D-self-calibration method with large freedom and high-precision performance for imaging metrology devices
  • 2015
  • Ingår i: Proceedings of the 15th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2015. - : Elsevier. - 9780956679079 ; , s. 159-160
  • Konferensbidrag (refereegranskat)abstract
    • When calibrating 2D (or 3D) metrology systems you need to rely on a traceable artefact for the calibration. However if the system you intend to calibrate has smaller uncertainties than the uncertainty of the reference artefact, the uncertainty of the instrument will be dominated by the artefact and not by the instrument. The only way to reveal the performance of the instrument is then to use self-calibration, i.e. a calibration without any externally verified references, except a 1D traceable measurement between two points on an artefact. Already in 1997, Mikael Raugh developed the rigorous mathematics for self-calibration of a 2D metrology stage, based on a lattice structured artefact. The original method and subsequent later improvements have in common that the problem is solved by using some assumptions regarding the artefact used in the calibration; like that the locations of the marks in the lattice are approximately known. There are also other constrains in the mathematical solution that limits its practical use in the industry. In this paper the application of a new general self-calibration algorithm is presented giving a large freedom to the positioning of the artefact, and also less demands on the 2D-structure on it. Rather than being based on rigorous mathematics requiring very exact positioning of the artefact, our algorithm is using a numerical iterative technique to minimize all overall errors. The algorithm is an enhancement of the self-calibration method already published by P. Ekberg et al. The algorithm has successfully been tested by simulations and by using real data from a white light interference microscope, yielding X, Y precision of few nm. The algorithm has also been used for separating distortions in ordinary low cost camera based systems opening up possibilities for accurate measurements in images. In the latter case the images can be compensated for most errors, like barrel or pin-cushion distortions, as well as perspective effects due to the angle of the camera relative the object.
  •  
36.
  • Ekberg, Peter, et al. (författare)
  • A new general approach for solving the self-calibration problem on large area 2D ultra-precision coordinate measurement machines
  • 2014
  • Ingår i: Measurement science and technology. - : IOP Publishing. - 0957-0233 .- 1361-6501. ; 25:5, s. 055001-
  • Tidskriftsartikel (refereegranskat)abstract
    • The manufacturing of flat panel displays requires a number of photomasks for the placement of pixel patterns and supporting transistor arrays. For large area photomasks, dedicated ultra-precision writers have been developed for the production of these chromium patterns on glass or quartz plates. The dimensional tolerances in X and Y for absolute pattern placement on these plates, with areas measured in square meters, are in the range of 200-300 nm (3 sigma). To verify these photomasks, 2D ultra-precision coordinate measurement machines are used having even tighter tolerance requirements. This paper will present how the world standard metrology tool used for verifying large masks, the Micronic Mydata MMS15000, is calibrated without any other references than the wavelength of the interferometers in an extremely well-controlled temperature environment. This process is called self-calibration and is the only way to calibrate the metrology tool, as no square-meter-sized large area 2D traceable artifact is available. The only parameter that cannot be found using self-calibration is the absolute length scale. To make the MMS15000 traceable, a 1D reference rod, calibrated at a national metrology lab, is used. The reference plates used in the calibration of the MMS15000 may have sizes up to 1 m(2) and a weight of 50 kg. Therefore, standard methods for self-calibration on a small scale with exact placements cannot be used in the large area case. A new, more general method had to be developed for the purpose of calibrating the MMS15000. Using this method, it is possible to calibrate the measurement tool down to an uncertainty level of <90 nm (3 sigma) over an area of (0.8 x 0.8) m(2). The method used, which is based on the concept of iteration, does not introduce any more noise than the random noise introduced by the measurements, resulting in the lowest possible noise level that can be achieved by any self-calibration method.
  •  
37.
  • Ekberg, Peter, 1955- (författare)
  • Development of a state-of-the-art nm-measurement system for square meter sized lithography masks
  • 2012
  • Ingår i: Proceedings of the 12th euspen International Conference 2012. ; , s. 57-62
  • Konferensbidrag (refereegranskat)abstract
    • The demands and solutions for ultra-precision metrology in the manufacturing of lithography masks for the display industry are indeed challenging. Specification demands to be overcome are a measurement repeatability of 10 nm (3 σ) and an absolute accuracy of better than 100 nm (3 σ) on a scale of more than 1.5 m in the X and Y directions. The design of a measurement system that meets these requirements calls for careful selections of materials such as metal, ceramic composites, quartz or glass as they at this precision level are highly affected by the surrounding temperature. Also the fact that the refractive index of air in the interferometers measuring absolute distances is affected by temperature, pressure, humidity and CO2 content make the reference measurements really challenging [1].As in many other areas in the industry high quality metrology is the key for success in developing high accuracy production tools. This paper will therefore start by introducing the metrology requirements of mask making for display screens and end with the state-of-the-art results we have achieved.
  •  
38.
  • Ekberg, Peter, et al. (författare)
  • Fast and accurate metrology of multi-layered ceramic materials by an automated boundary detection algorithm developed for optical coherence tomography data
  • 2014
  • Ingår i: Optical Society of America. Journal A. - 1084-7529 .- 1520-8532. ; 31:2, s. 217-226
  • Tidskriftsartikel (refereegranskat)abstract
    • Optical coherence tomography (OCT) is useful for materials defect analysis and inspection with the additional possibility of quantitative dimensional metrology. Here, we present an automated image-processing algorithm for OCT analysis of roll-to-roll multilayers in 3D manufacturing of advanced ceramics. It has the advantage of avoiding filtering and preset modeling, and will, thus, introduce a simplification. The algorithm is validated for its capability of measuring the thickness of ceramic layers, extracting the boundaries of embedded features with irregular shapes, and detecting the geometric deformations. The accuracy of the algorithm is very high, and the reliability is better than 1 mu m when evaluating with the OCT images using the same gauge block step height reference. The method may be suitable for industrial applications to the rapid inspection of manufactured samples with high accuracy and robustness.
  •  
39.
  • Ekberg, Peter, et al. (författare)
  • High-precision lateral distortion measurement and correction in coherence scanning interferometry using an arbitrary surface
  • 2017
  • Ingår i: Optics Express. - : OPTICAL SOC AMER. - 1094-4087. ; 25:16, s. 18703-18712
  • Tidskriftsartikel (refereegranskat)abstract
    • Lateral optical distortion is present in most optical imaging systems. In coherence scanning interferometry, distortion may cause field-dependent systematic errors in the measurement of surface topography. These errors become critical when high-precision surfaces, e.g. precision optics, are measured. Current calibration and correction methods for distortion require some form of calibration artefact that has a smooth local surface and a grid of high-precision manufactured features. Moreover, to ensure high accuracy and precision of the absolute and relative locations of the features of these artefacts, requires their positions to be determined using a traceable measuring instrument, e.g. a metrological atomic force microscope. Thus, the manufacturing and calibration processes for calibration artefacts are often expensive and complex. In this paper, we demonstrate for the first time the calibration and correction of optical distortion in a coherence scanning interferometer system by using an arbitrary surface that contains some deviations from flat and has some features (possibly just contamination), such that feature detection is possible. By using image processing and a self-calibration technique, a precision of a few nanometres is achieved for the distortion correction. An inexpensive metal surface, e.g. the surface of a coin, or a scratched and defected mirror, which can be easily found in a laboratory or workshop, may be used. The cost of the distortion correction with nanometre level precision is reduced to almost zero if the absolute scale is not required. Although an absolute scale is still needed to make the calibration traceable, the problem of obtaining the traceability is simplified as only a traceable measure of the distance between two arbitrary points is needed. Thus, the total cost of transferring the traceability may also be reduced significantly using the proposed method. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License.
  •  
40.
  • Ekberg, Peter, 1955- (författare)
  • Metrology : a forgotten added value maker that eliminates cost of poor qualityand supports a sustainable zero defect production
  • 2012
  • Ingår i: The 5th International Swedish Production Symposium.
  • Konferensbidrag (refereegranskat)abstract
    • The purpose of this paper is to highlight the importance of metrology in the industrial production process.Different kinds of processes, like mass production of parts and the very special photo mask process will bediscussed. It will be shown how much impact metrology has on the added value of the product in the latterprocess. Proper inspection planning with feedbacks from the process at certain points is very important forboth keeping up the yield and also keeping the process stable. In the example presented about the photomask process bad inspection planning will have extreme consequences. Another aspect that will bediscussed is the problem when metrology tools or production tools do not fulfil their intended specifications.In many cases the user is completely dependent on the tools without any chance to verify their performance.This will of course lead to poor quality. Solutions to these kinds of problems generate additional costs ininvestments but will in the long run pay off since quality can be assured.
  •  
41.
  • Ekberg, Peter, et al. (författare)
  • Past and future challenges from a display mask writer perspective
  • 2012
  • Ingår i: Photomask and Next-Generation Lithography Mask Technology XIX. - : SPIE - International Society for Optical Engineering. - 9780819491367 ; , s. 84410N-
  • Konferensbidrag (refereegranskat)abstract
    • Since its breakthrough, the liquid crystal technology has continued to gain momentum and the LCD is today the dominating display type used in desktop monitors, television sets, mobile phones as well as other mobile devices. To improve production efficiency and enable larger screen sizes, the LCD industry has step by step increased the size of the mother glass used in the LCD manufacturing process. Initially the mother glass was only around 0.1 m 2 large, but with each generation the size has increased and with generation 10 the area reaches close to 10 m2. The increase in mother glass size has in turn led to an increase in the size of the photomasks used - currently the largest masks are around 1.6 &times; 1.8 meters. A key mask performance criterion is the absence of "mura" - small systematic errors captured only by the very sensitive human eye. To eliminate such systematic errors, special techniques have been developed by Micronic Mydata. Some mura suppressing techniques are described in this paper. Today, the race towards larger glass sizes has come to a halt and a new race - towards higher resolution and better image quality - is ongoing. The display mask is therefore going through a change that resembles what the semiconductor mask went through some time ago: OPC features are introduced, CD requirements are increasing sharply and multi tone masks (MTMs) are widely used. Supporting this development, Micronic Mydata has introduced a number of compensation methods in the writer, such as Z-correction, CD map and distortion control. In addition, Micronic Mydata MMS15000, the world's most precise large area metrology tool, has played an important role in improving mask placement quality and is briefly described in this paper. Furthermore, proposed specifications and system architecture concept for a new generation mask writers - able to fulfill future image quality requirements - is presented in this paper. This new system would use an AOD/AOM writing engine and be capable of resolving 0.6 micron features.
  •  
42.
  • Ekberg, Peter, et al. (författare)
  • Traceable X,Y self-calibration at single nm level of an optical microscope used for coherence scanning interferometry
  • 2018
  • Ingår i: Measurement science and technology. - : IOP PUBLISHING LTD. - 0957-0233 .- 1361-6501. ; 29:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Coherence scanning interferometry used in optical profilers are typically good for Z-calibration at nm-levels, but the X,Y accuracy is often left without further notice than typical resolution limits of the optics, i.e. of the order of similar to 1 mu m. For the calibration of metrology tools we rely on traceable artefacts, e.g. gauge blocks for traditional coordinate measurement machines, and lithographically mask made artefacts for microscope calibrations. In situations where the repeatability and accuracy of the measurement tool is much better than the uncertainty of the traceable artefact, we are bound to specify the uncertainty based on the calibration artefact rather than on the measurement tool. This is a big drawback as the specified uncertainty of a calibrated measurement may shrink the available manufacturing tolerance. To improve the uncertainty in X, Y we can use self-calibration. Then, we do not need to know anything more than that the artefact contains a pattern with some nominal grid. This also gives the opportunity to manufacture the artefact in-house, rather than buying a calibrated and expensive artefact. The self-calibration approach we present here is based on an iteration algorithm, rather than the traditional mathematical inversion, and it leads to much more relaxed constrains on the input measurements. In this paper we show how the X, Y errors, primarily optical distortions, within the field of view (FOV) of an optical coherence scanning interferometry microscope, can be reduced with a large factor. By self-calibration we achieve an X, Y consistency in the 175 x 175 mu m(2) FOV of similar to 2.3 nm (1 sigma) using the 50x objective. Besides the calibrated coordinate X, Y system of the microscope we also receive, as a bonus, the absolute positions of the pattern in the artefact with a combined uncertainty of 6 nm (1s) by relying on a traceable 1D linear measurement of a twin artefact at NIST.
  •  
43.
  • Ekberg, Peter, et al. (författare)
  • Ultra-precision geometrical measurement technique based on a statistical random phase clock combined with acoustic-optical deflection
  • 2010
  • Ingår i: Measurement science and technology. - : IOP Publishing. - 0957-0233 .- 1361-6501. ; 21:12, s. 125103-
  • Tidskriftsartikel (refereegranskat)abstract
    • Mask writers and large area measurements systems are key systems for production of large liquid crystal displays (LCD) and image devices. With position tolerances in the sub-mu m range over square meter sized masks, the metrology challenges are indeed demanding. Most systems used for this type of measurement rely on a microscope camera imaging system, provided with a charge coupled device, a complementary metal-oxide-semiconductor sensor or a time delay and integration sensor to transform the optical image to a digital gray-level image. From this image, processing algorithms are used to extract information such as location of edges. The drawback of this technique is the vast amount of data captured but never used. This paper presents a new approach for ultra-high-precision lateral measurement at nm-levels of chrome/glass patterns separated by centimeters, so called registration marks, on masks used for the LCD manufacturing. Registration specifications demand a positioning accuracy <200 nm and critical dimensions, i.e. chrome line widths, which need to be accurate in the 80 nm range. This accuracy has to be achieved on glass masks of 2.4 x 1.6 m(2) size. Our new measurement method is based on nm-precise lateral scanning of a focused laser beam combined with statistical random phase sampling of the reflected signal. The precise scanning is based on an extremely accurate time measuring device controlling an acousto optic deflector crystal. The method has been successfully applied in measuring the 4 mu m pitch of reference gratings at standard deviations sigma of 0.5 nm and registration marks separated by several cm at standard deviations of 23 nm.
  •  
44.
  • Ekberg, Peter (författare)
  • Ultra precision metrology : the key for mask lithography and manufacturing of high definition displays
  • 2011
  • Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Metrology is the science of measurement. It is also a prerequisite for maintaining a high quality in all manufacturing processes. In this thesis we will present the demands and solutions for ultra-precision metrology in the manufacturing of lithography masks for the TV-display industry. The extreme challenge that needs to be overcome is a measurement uncertainty of 10 nm on an absolute scale of more that 2 meters in X and Y. Materials such as metal, ceramic composites, quartz or glass are highly affected by the surrounding temperature when tolerances are specified at nanometer levels. Also the fact that the refractive index of air in the interferometers measuring absolute distances is affected by temperature, pressure, humidity and CO2 contents makes the reference measurements really challenging. This goes hand in hand with the ability of how to design a mask writer, a pattern generator with a performance good enough for writing masks for the display industry with sub-micron accuracy over areas of square meters.  As in many other areas in the industry high quality metrology is the key for success in developing high accuracy production tools. The aim of this thesis is therefore to discuss the metrology requirements of mask making for display screens. Defects that cause stripes in the image of a display, the so called “Mura” effect, are extremely difficult to measure as they are caused by spatially systematic errors in the mask writing process in the range of 10-20 nm. These errors may spatially extend in several hundreds of mm and are superposed by random noise with significantly higher amplitude compared to the 10-20 nm.  A novel method for measuring chromium patterns on glass substrates will also be presented in this thesis. This method will be compared to methods based on CCD and CMOS images. Different methods have been implementedin the Micronic MMS1500 large area measuring machine, which is the metrology tool used by the mask industry, for verifying the masks made by the Micronic mask writers. Using alternative methods in the same system has been very efficient for handling different measurement situations. Some of  the discussed methods are also used by the writers for calibration purposes.  
  •  
45.
  • Ekberg, Peter (författare)
  • Z-correction, a method for achieving ultra-high absolute pattern placement accuracy of large area photomasks
  • 2013
  • Ingår i: Proceedings of the 13th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2013. - : euspen. - 9780956679024 ; , s. 253-256
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • Photomasks are used in the production of LCD, OLED and other kinds of displays. For TV displays these photomasks, made of quartz glass with a Cr pattern, may have sizes up to 1.62 × 1.78 m2 and a thickness up to 16 mm. The absolute placement accuracy, i.e. ×,Y position of a pi×el or line in the mask pattern needs to be better than 150 nm (3s). The demand for higher resolution displays has led to tighter flatness requirements of the photomask, to secure that the chrome pattern is always in best focus. In contrast to small area semiconductor masks with dimensions up to 300 × 300 mm2and three point supports, the large area photomasks have to rest on a large stage in the mask writer. It is then unavoidable that distortions will be induced due to the fact that the glass backside or stage surface is not perfectly flat. If not corrected for, these distortions in Z direction can easily generate geometrical errors in the ×,Y plane corresponding to pattern displacements of several hundred nanometers. To avoid these ×,Y errors we have developed a technique called Z-correction. It is a function developed for correcting the mask pattern placement prior to the writing process in the pattern generator or in a verification measurement in the MMS15000 metrology tool [1]. This is the first time this method is used for improving the accuracy of photo masks. It is based on height measurements of the quartz glass when it is resting on the stage during the temperature stabilizing time. Without using Z-correction it is very challenging to achieve an absolute uncertainty better than ∼200 nm (3s) over an area of 0.8 × 0.8 m2. With Z-correction it is possible to enhance this number to < 100 nm (3s). In the MMS15000 metrology tool the performance is even better, ∼50 nm (3s) over a 0.8 × 0.8 m2 stage area when using Z-correction in the self-calibration process. [2] [3].
  •  
46.
  • Ekberg, Peter, et al. (författare)
  • Z-correction, a method for achieving ultraprecise self-calibration on large area coordinate measurement machines for photomasks
  • 2014
  • Ingår i: Measurement science and technology. - : IOP Publishing. - 0957-0233 .- 1361-6501. ; 25:5, s. 055002-
  • Tidskriftsartikel (refereegranskat)abstract
    • High-quality photomasks are a prerequisite for the production of flat panel TVs, tablets and other kinds of high-resolution displays. During the past years, the resolution demand has become more and more accelerated, and today, the high-definition standard HD, 1920 x 1080 pixels(2), is well established, and already the next-generation so-called ultra-high-definition UHD or 4K display is entering the market. Highly advanced mask writers are used to produce the photomasks needed for the production of such displays. The dimensional tolerance in X and Y on absolute pattern placement on these photomasks, with sizes of square meters, has been in the range of 200-300 nm (3 sigma), but is now on the way to be <150 nm (3 sigma). To verify these photomasks, 2D ultra-precision coordinate measurement machines are used with even tighter tolerance requirements. The metrology tool MMS15000 is today the world standard tool used for the verification of large area photomasks. This paper will present a method called Z-correction that has been developed for the purpose of improving the absolute X, Y placement accuracy of features on the photomask in the writing process. However, Z-correction is also a prerequisite for achieving X and Y uncertainty levels <90 nm (3 sigma) in the self-calibration process of the MMS15000 stage area of 1.4 x 1.5 m(2). When talking of uncertainty specifications below 200 nm (3 sigma) of such a large area, the calibration object used, here an 8-16 mmthick quartz plate of size approximately a square meter, cannot be treated as a rigid body. The reason for this is that the absolute shape of the plate will be affected by gravity and will therefore not be the same at different places on the measurement machine stage when it is used in the self-calibration process. This mechanical deformation will stretch or compress the top surface (i.e. the image side) of the plate where the pattern resides, and therefore spatially deform the mask pattern in the X- and Y-directions. Errors due to this deformation can easily be several hundred nanometers. When Z-correction is used in the writer, it is also possible to relax the flatness demand of the photomask backside, leading to reduced manufacturing costs of the plates.
  •  
47.
  • Elinder, Carl-Gustaf, et al. (författare)
  • Variations in graft and patient survival after kidney transplantation in Sweden: caveats in interpretation of center effects when benchmarking.
  • 2009
  • Ingår i: Transplant international : official journal of the European Society for Organ Transplantation. - : Frontiers Media SA. - 1432-2277 .- 0934-0874. ; 22:11, s. 1051-7
  • Tidskriftsartikel (refereegranskat)abstract
    • Benchmarking and comparisons between transplantation centers are becoming more common. A crude comparison indicated a 50% difference in patient survival between centers in Sweden. A 'task group' was formed to refute or confirm and learn from this observation. Patient survival and graft survival of 5 933 patients transplanted at three different transplantation centers in Sweden (Stockholm, Göteborg, and Malmö) were followed up until February 2007. Patient survival and graft survival were compared between the centers with and without consideration being given to important covariates such as time period, type of donation (living or deceased donor), gender, and age. A refined cohort of 2,956 adult patients that had been transplanted for the first time between 1991 and 2007 was assessed in more detail using Cox regression analysis. The difference in patient and transplant outcome observed in the crude comparison diminished considerably after adjustment for differences in case mix and time period of transplantation, and was neither evident nor significant after 1999. Patient survival and graft survival have improved considerably during the time period since 1991. The adjusted hazards ratio for mortality was 0.39 (95% CI 0.29-0.53) for patients who were transplanted after 1999 when compared with those transplanted between 1991 and 1994. Crude comparisons between results from transplantation centers may be severely confounded not only by case mix but also by differences in the proportion of patients transplanted during different time periods. Patient outcome and graft outcome have improved considerably since 1991, and after 1999 center effects were no longer apparent in Sweden.
  •  
48.
  • Filipsson, Peter J, 1985, et al. (författare)
  • Luftflöde i vårdlokaler - Med ett fastighetstekniskt perspektiv
  • 2024
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Denna rapport, initierad och finansierad av PTS Forum, rör ventilation för begränsning av risken för luftburen smittspridning i vårdlokaler. Arbetet är begränsat till tre specifika rumstyper: vårdrum, undersökningsrum och väntrum. Ökat ventilationsluftflöde innebär generellt en minskad risk för luftburen smittspridning. Rapporten tar avstamp från detta centrala samband men gräver dessutom djupare i andra aspekter som också bör tas hänsyn till vid framtagande av rekommendationer och riktlinjer. Dessa aspekter är: -Det finns negativa konsekvenser förknippade med ökat luftflöde. -Vedertagna teoretiska samband mellan luftflöde och smittrisk är i många avseenden förenklingar, ofta till fördel för fördelarna med ökat luftflöde.  -Det finns andra, varav vissa mer effektiva, sätt att reducera smittrisk. -Fördelen med högre luftflöde beror på mängden smittämnen som genereras i rummet. Den första punkten handlar primärt om kostnader och miljöpåverkan orsakade av energibehov, utrymmesbehov och behov av tekniska installationer, men även konsekvenser för inomhusmiljön. Exempel på de förenklingar som avses i den andra punkten är att den ursprungliga s.k. Wells-Rileymodellen inte tar hänsyn till andra smittrisksänkande fenomen än just ventilation samt att ventilationseffektiviteten normalt antas vara oberoende av luftflödet. Den tredje punkten är viktig eftersom nyttan av olika smittrisksänkande åtgärder inte går att addera med varandra. Nyttan av ökat luftflöde är väldigt stor i fall där alla andra parametrar gynnar smittspridning, men om andra åtgärder vidtas parallellt (t.ex. munskydd) så sjunker nyttan med ökat luftflöde drastiskt. Eftersom de negativa konsekvenserna av ökat luftflöde är oförändrade så blir de andra åtgärderna väldigt avgörande för vad som är ett optimalt luftflöde. Den fjärde punkten innebär att det i rum utan smittsamma personer inte finns några smittsänkande fördelar alls med ett högre luftflöde. Tvärtom, om ett centralt återluftssystem har varit nödvändigt för att ha råd med det högre luftflödet så innebär ventilationen i stället en ökad smittrisk. I rum där det genereras mycket smitta finns det däremot desto större fördel med ett högt luftflöde (oavsett om det är uteluft eller väl filtrerad återluft). Förutom att detta motiverar olika luftflöden i olika rumstyper så motiverar det tillfälligt högre luftflöden vid händelse av pandemiutbrott, vilket t.ex. har anammats i amerikanska standarder.  Beräkningarna i rapporten visar till exempel att en ökning av uteluftflödet från 2 till 4 luftomsättningar per timme reducerar risken för luftburen smitta med 40 % till en kostnad av 2 080 kr/m2 (inklusive nuvärdet av framtida energikostnader). 25 % av kostnaden hänförs till ökat energibehov, drygt 40 % till ökat behov av tekniska installationer och drygt 30 % till ökat utrymmesbehov. Utöver detta medför luftflödesökningen utsläpp av 16,5 kgCO2e/m2 vid uppförandet av byggnaden och 1,4 kgCO2e/m2år till följd av ökad energianvändning. Därtill kommer betydande risk för försämrad inomhusmiljö. I ett realistiskt scenario ökar ljudnivån med 3 dB och andelen personer som kan förväntas besväras av drag med 7 procentenheter. Inomhusluften kommer bli torrare, men i hur hög grad beror på ventilationsaggregatets fuktåtervinnande egenskaper och har inte uppskattats i den här studien. Exempel på andra sätt att sänka smittrisken är att installera en rumsluftrenare, installera desinficerande UV-ljus, använda munskydd och att förbättra luftföringen. Värdet av att reducera risken för luftburen smitta (på avstånd >1.0 m) i de aktuella rummen beror helt och hållet på hur många fall av överförd smitta detta i praktiken motsvarar. Rekommendationer om smittrisksänkande åtgärder bör därför föregås av en, åtminstone grov, uppskattning av den faktiska incidensen (dvs. antal fall av överförd smitta).
  •  
49.
  •  
50.
  • Gustavsson, Maria, 1962-, et al. (författare)
  • Lokalt ledarskap i en global organisation : kvinnors och mäns möjligheter att bli chefer och utöva ledarskap inom ett verkstadsindustriföretag
  • 2008
  • Rapport (övrigt vetenskapligt/konstnärligt)abstract
    • Frågor som rör chef- och ledarskap genererar alltid ett stort intresse såväl i arbetslivet som inom forskning. Det tema som fokuseras i den här rapporten är chef-/ledarskap och kön, särskilt könsfördelningen på ledande befattningar. I dagsläget är merparten av alla chefer i svenskt arbetsliv män. Män är överrepresenterade på chefsbefattningar i relation till samtliga anställda män i såväl privat som offentlig sektor. På de högsta chefsbefattningarna blir mansdominansen än tydligare (SCB, 2006). Mansdominansen på ledande befattningar kan sägas utgöra en utgångspunkt för de forskningsfrågor som formulerats inom forskningsområdet chef-/ledarskap och kön. Forskningsfrågorna handlar t.ex. om varför så få kvinnor är chefer samt på senare år om hur ledarskap är könsmärkt, dvs. hur ledarskap förknippas med kön. En återkommande fråga i mansdominerade organisationer är: Hur kan vi få fler kvinnor på ledande befattningar? Det är just denna problematik som fokuseras i föreliggande rapport som sammanfattar erfarenheter från ett forsknings- och utvecklingsprojekt som pågick från senhösten 2007 till senhösten 2008.Syftet med föreliggande rapport är att kartlägga och analysera villkor för kvinnor och män att bli chefer och att utöva chef- och ledarskap, samt varför få kvinnor har chefspositioner. Utgångspunkten för denna analys är en empirisk studie inom ett globalt verkstadsindustriföretag baserad på intervjuer med chefer, både kvinnor och män, på olika chefsnivåer och från olika divisioner. Följande mer specifika frågeställningar har formulerats:Vad karaktäriserar chefernas uppfattningar om ledarskap, chefsrekrytering, lärande och karriär, jämställdhet samt hälsa i företaget?Vilka förutsättningar finns för kvinnor och män att rekryteras till chefspositioner samt utöva chef- och ledarskap i företaget?Vilka orsaker finns till varför få kvinnor har chefspositioner i företaget?För att kunna diskutera skillnader mellan kvinnors och mäns uppfattningar och villkor närmar vi oss forskningsfrågorna utifrån ett genusperspektiv. Med genusperspektiv avser vi i denna rapport synsättet att vi formas till kvinnor och män genom det vi gör, och de aktiviteter vi deltar i, i samspel med andra människor i det dagliga arbetet. Våra könsidentiteter är beroende av rådande, socialt konstruerade, föreställningar i samhället och vi lär oss och lär oss att förhålla oss till dessa föreställningar i det dagliga arbetet. Vi utvecklar dessa tankar ytterligare i kapitel 2.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-50 av 101
Typ av publikation
tidskriftsartikel (71)
konferensbidrag (20)
rapport (3)
doktorsavhandling (3)
bok (2)
bokkapitel (1)
visa fler...
licentiatavhandling (1)
visa färre...
Typ av innehåll
refereegranskat (82)
övrigt vetenskapligt/konstnärligt (18)
populärvet., debatt m.m. (1)
Författare/redaktör
Ekberg, Olle (27)
Ekberg, Peter (26)
Leander, Peter (15)
Mattsson, Lars (15)
Ekberg, Anders, 1967 (6)
Svensson, Peter (5)
visa fler...
Aspelin, Peter (5)
Sundin, Maria, 1965 (5)
Ekberg, EwaCarin (4)
List, Thomas (4)
Alstergren, Per (4)
Ohrbach, Richard (4)
Månsson, Sven (4)
Löfdahl, Claes-Göran (4)
Hakansson, K (4)
Peck, Christopher C. (4)
Nilsson, Ing-Marie (4)
Lobbezoo, Frank (4)
Wahlund, Kerstin (4)
Kapos, Flavia P (4)
Sharma, Sonia (4)
Durham, Justin (4)
Hirsch, Christian (4)
Diaz, Sandra (3)
Piitulainen, Eeva (3)
Su, Rong (3)
Ohlsson, Bodil (3)
Kabo, Elena, 1972 (3)
Al-Khotani, Amal (3)
Magnusson, Peter (3)
Åkeson, Per (3)
Ekberg, Henrik (3)
Bernhardt, Peter, 19 ... (3)
Ekberg, Kerstin (3)
Palermo, Tonya M. (3)
Johnsson, Andreas, 1 ... (3)
Besen, Elyssa (3)
Ekberg, Marie (3)
Conti, Paulo César R ... (3)
Michelotti, Ambrosin ... (3)
Daemi, Bita, 1982- (3)
Mattsson, Lars, 1950 ... (3)
Ekberg, Peter, 1955- (3)
Casselbrant, Ingrid (3)
Peterson, Barry (3)
Koutris, Michail (3)
Penlington, Chris (3)
Visscher, Corine M. (3)
Goulet, Jean-Paul (3)
King, Christopher D (3)
visa färre...
Lärosäte
Lunds universitet (40)
Kungliga Tekniska Högskolan (29)
Karolinska Institutet (18)
Göteborgs universitet (11)
Chalmers tekniska högskola (10)
Linköpings universitet (9)
visa fler...
Uppsala universitet (5)
Malmö universitet (4)
Umeå universitet (2)
Örebro universitet (2)
Högskolan i Skövde (1)
Kungl. Konsthögskolan (1)
visa färre...
Språk
Engelska (96)
Svenska (5)
Forskningsämne (UKÄ/SCB)
Medicin och hälsovetenskap (50)
Teknik (25)
Naturvetenskap (14)
Samhällsvetenskap (7)
Humaniora (7)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy