| 1. |
- Arvanitis, Leena, et al.
(författare)
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Novel antagonistic interactions associated with plant polyploidization influence trait selection and habitat preference.
- 2010
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 13:3, s. 330-7
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Tidskriftsartikel (refereegranskat)abstract
- Polyploidization is an important mechanism for sympatric speciation in plants. Still, we know little about whether plant polyploidization leads to insect host shifts, and if novel interactions influence habitat and trait selection in plants. We investigated herbivory by the flower bud gall-forming midge Dasineura cardaminis on tetraploids and octoploids of the herb Cardamine pratensis. Gall midges attacked only octoploid plant populations, and a transplantation experiment confirmed this preference. Attack rates were higher in populations that were shaded, highly connected or occurred along stream margins. Within populations, late-flowering individuals with many flowers were most attacked. Galling reduced seed production and significantly influenced phenotypic selection on flower number. Our results suggest that an increase in ploidy may lead to insect host shifts and that plant ploidy explains insect host use. In newly formed plant polyploids, novel interactions may alter habitat preferences and trait selection, and influence the further evolution of cytotypes.
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| 2. |
- Box, Marcus
(författare)
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New Venture, Survival, Growth : Continuance, Termination and Growth of Business Firms and Business Populations in Sweden During the 20th Century
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This dissertation focuses on the formation, growth and discontinuance of business populations and firms in Sweden during the 20th century. It addresses some key issues in the domain of economic and social sciences, and in particular entrepreneurship and small business research: if and when firms grow, stagnate and decline, as well as how long firms survive and when they are likely to disband. Previous research has primarily analyzed these questions from a short time frame. Further, an individual or firm-oriented focus is commonly assumed. In that, alternative or complementary explanations to the growth and survival of firms may be disregarded. In contrast to much previous research, this dissertation assumes a micro-to-macro, longitudinal and demographic population approach. The period of investigation is over one hundred years. In addressing the growth and survival of firms, it takes into account the impact of firm-specific structural factors (such as firm age and size), generation (cohort) effects, as well as the influence of macroeconomic, exogenous factors. Further, the relationship between managerial/ownership succession and firm performance is also addressed. Both cross-sectional and longitudinal databases are employed in the dissertation. Its main empirical material consists of unique longitudinal data on new business firms, traced at the firm level from their birth to their termination. More specifically, seven birth cohorts – generations – of approximately 2,200 firms founded in 1899, 1909, 1912, 1921, 1930, 1942 and 1950 are included. The main findings show that ownership/management succession in firms had a quite weak correlation with firm performance and survival. At least at an aggregate level, and with some exceptions, it is debatable if the loss and replacement of owner-managers in small and in larger firms have any observable effects on firm performance. Furthermore, macroeconomic phenomena influence the conditions of individual firms as well as populations/aggregates of businesses. Both the growth and termination of firms and firm populations are found to be related to real economic (environmental) conditions; e.g. favorable macroeconomic conditions implied that firms grew in size. At the same time, under certain circumstances, the influence of structural variables (firm age and size) – as suggested in much previous research – is found to be of importance. As concerns firm growth, as well as firm termination, the economic environment and structural factors interact. These findings challenges individual or firm-level research that mainly focus on personal traits and behaviors in explaining firm success and failure. Other previous assumptions are also challenged when taking a longer time perspective into consideration. For decades, organization and business research have acknowledged a liability of newness and of size for business firms. While this might be true under some conditions, this liability of newness is falsified in the study: the termination behavior of some firm generations did not correspond with these assumptions. Thus, the perspectives and methodology applied in the dissertation complement earlier approaches in entrepreneurship and small business research.
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| 3. |
- Doherty, Patrick, 1957-, et al.
(författare)
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The WITAS unmanned aerial vehicle project
- 2000
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Ingår i: Proceedings of the 14th European Conference on Artificial Intelligence (ECAI). - Amsterdam : IOS Press. - 1586030132 - 4274903885 ; , s. 747-755
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Konferensbidrag (refereegranskat)abstract
- The purpose of this paper is to provide a broad overview of the WITAS Unmanned Aerial Vehicle Project. The WITAS UAV project is an ambitious, long-term basic research project with the goal of developing technologies and functionalities necessary for the successful deployment of a fully autonomous UAV operating over diverse geographical terrain containing road and traffic networks. Theproject is multi-disciplinary in nature, requiring many different research competences, and covering a broad spectrum of basic research issues, many of which relate to current topics in artificial intelligence. A number of topics considered are knowledge representation issues, active vision systems and their integration with deliberative/reactive architectures, helicopter modeling and control, ground operator dialogue systems, actual physical platforms, and a number of simulation techniques.
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| 4. |
- Eriksson Wiklund, Ann-Kristin, et al.
(författare)
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Contaminants and habitat choice in the Baltic Sea: Behavioural experiments with the native species, Monoporeia affinis, and the invasive genus, Marenzelleria
- 2009
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Ingår i: Estuarine, Coastal and Shelf Science. - : Elsevier BV. - 0272-7714 .- 1096-0015. ; 81, s. 238-246
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Tidskriftsartikel (refereegranskat)abstract
- The invasive polychaete genus, Marenzelleria and the native amphipod, Monoporeia affinis are food and habitat competitors in the Baltic Sea. Previous studies have shown that moderate densities of Marenzelleria can affect the behaviour of M. affinis. To examine the short-term interactive effects of interspecific habitat choice and environmental contaminants a series of habitat colonisation experiments were performed. The contaminants examined included harbor sediments and sediment spiked with the antifouling substances, Cu, Zn and Irgarol. Polychaetes and amphipods were exposed to contaminants in single-species and two-species experiments. In spiked-sediment experiments, M. affinis showed clear dose-dependent response. These experiments verified that behavioural response of M. affinis to different habitats is a sensitive method for testing toxicity under controlled conditions. In experiments with three different harbor sediments and reference sediment both species showed the lowest preference for the reference sediment. This sediment also had the lowest content of quality food, indicating that factors such as food quality and quantity may override the disturbing effects of contaminants in natural sediments. The presence of Marenzelleria spp. did not affect amphipod habitat choice, indicating no short-term effects, which implies that both species can co-exist provided sufficient food is available.
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| 5. |
- Fogelström, Elsa, et al.
(författare)
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Plant-herbivore synchrony and selection on plant flowering phenology
- 2017
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Ingår i: Ecology. - : Wiley. - 0012-9658 .- 1939-9170. ; 98:3, s. 703-711
-
Tidskriftsartikel (refereegranskat)abstract
- Temporal variation in natural selection has profound effects on the evolutionary trajectories of populations. One potential source of variation in selection is that differences in thermal reaction norms and temperature influence the relative phenology of interacting species. We manipulated the phenology of the butterfly herbivore Anthocharis cardamines relative to genetically identical populations of its host plant, Cardamine pratensis, and examined the effects on butterfly preferences and selection acting on the host plant. We found that butterflies preferred plants at an intermediate flowering stage, regardless of the timing of butterfly flight relative to flowering onset of the population. Consequently, the probability that plant genotypes differing in timing of flowering should experience a butterfly attack depended strongly on relative phenology. These results suggest that differences in spring temperature influence the direction of herbivore-mediated selection on flowering phenology, and that climatic conditions can influence natural selection also when phenotypic preferences remain constant.
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| 6. |
- Granlund, Gösta H., et al.
(författare)
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Issues in Robot Vision
- 1994
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Ingår i: Image and Vision Computing. - : Elsevier BV. - 0262-8856 .- 1872-8138. ; 12:3, s. 131-148
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we discuss certain issues regarding robot vision. The main theme will be the importance of the choice of information representation. We will see the implications at different parts of a robot vision structure. We deal with aspects of pre-attentive versus attentive vision, control mechanisms for low level focus of attention, and representation of motion as the orientation of hyperplanes in multdimensional time-space. Issues of scale will be touched upon, and finally, a depth-from stereo algorithm based on guadrature filter phase is presented.
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| 7. |
- Hassila, Carl Johan
(författare)
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Additive Manufacturing of Ni-Fe Superalloys : Exploring the Alloying Envelope and the Impact of Process on Mechanical Properties
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Additive manufacturing of metals has received a lot of attention in the last decade as this family of manufacturing processes allows the manufacturing of complicated geometries which would be difficult to produce using conventional manufacturing techniques. Additive manufacturing of the Ni-Fe based superalloys 625 and 718 using the Powder Bed Fusion – Laser Beam (PBF-LB) process is facilitated by the fact that these alloys were developed as weldable alternatives to other high-strength, high-temperature Ni-based superalloys. However, given that these alloys were developed with casting and forging as the main manufacturing route, the alloying composition of these alloys may possibly be tuned to better suit the PBF-LB process. In this thesis, small changes to the alloy 625 and 718 alloy compositions were made, with the goal of either improving material properties or reducing the environmental footprint of the produced materials. For alloy 718, the influence of carbon content on the resulting microstructure and mechanical properties was investigated both in the as-built and heat-treated conditions using tensile and impact testing. A similar study, but also including corrosion experiments, was performed on an alloy 625 composition which had been tuned to allow it to be atomized using nitrogen instead of argon, a transition that results in environmental benefits as argon gas carries with it a larger environmental footprint compared to nitrogen gas. In addition to the above, as the process conditions in the PBF-LB process have a strong influence on the developing microstructure, their influence on rolling contact fatigue and residual stresses in printed alloys 625 and 718 were investigated. Rolling contact fatigue experiments were performed on alloy 625 and were complemented by a fractographic study which showed that the different grain structures achieved depending on the used process condition affected the pitting damage development. Meanwhile, the residual stress experiments were performed on PBF-LB processed alloy 625 and 718. The residual stresses in the materials were first calculated using experimental data attained from high energy synchrotron diffraction experiments. These results were then compared to the predicted stresses from a thermo-mechanical model. The thermomechanical model included a built-in mechanism-based material model which was shown to successfully simulate relaxation effects stemming from the cyclic heating of the material during the PBF-LB process. Lastly, a modelling approach using the thermo-mechanical model was developed which allowed the model to successfully predict the stresses also when using different scanning strategies.
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| 8. |
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| 9. |
- Hassila Karlsson, Carl Johan, et al.
(författare)
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Influence of scanning strategy on residual stresses in laser powder bed fusion manufactured alloy 718: Modeling and experiments
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Residual stresses are a known phenomenon in additively manufactured materials. The residual stresses increase the risk of cracks, limit in-service performance, and distort printed parts. In this work, thermo-mechanical finite element models using the hatch-by-hatch and layer-by-layer approach, and the inherent strain method has been developed and applied to predict the effects of different scanning strategies on the deflection and the residual stresses of two PBF-LB processed geometries. To account for viscoplasticty and relaxation effects, a mechanism-based material model have been implemented and used. It is shown that the hatch-by-hatch approach and inherent strain method both successfully predicted the experimentally measured deflections of the first geometry, which was printed using different scanning directions. To predict the stress field experimentally, high-energy synchrotron measurements have been used to. The thermo-mechanical models and the inherent strain method both captures the trend of experimentally measured residual stress fields, although with an overall underprediction. The predictions of the models were evaluated, and their accuracy discussed in terms of physical aspects of the Powder Bed Fusion – Laser Beam process.
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| 10. |
- Herlitz, Johan, 1949, et al.
(författare)
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Morbidity and quality of life 5 years after early intervention with metoprolol in suspected acute myocardial infarction.
- 1988
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Ingår i: Cardiology. - : Karger AG. - 0008-6312 .- 1421-9751. ; 75:5, s. 357-64
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Tidskriftsartikel (refereegranskat)abstract
- In 1,395 patients in the age range 40-74 years participating in a double-blind trial with metoprolol in suspected acute myocardial infarction morbidity and quality of life were assessed during the first 5 years after randomization. During the first 3 months patients were given 200 mg metoprolol daily or placebo. Thereafter the two groups were treated similarly. Mortality during 5 years was 24.2% in patients originally randomized to metoprolol versus 25.7% in patients originally randomized to placebo (p greater than 0.2). No difference was observed regarding reinfarction rate, stroke or occurrence of bypass surgery during the 5-year follow-up. During the first 3 months 10% of patients in the metoprolol group were rehospitalized for various reasons versus 13% in the placebo group. The corresponding figures for 5 years were 59 and 60%, respectively. Among patients surviving 5 years 84% in both groups were on some medication of which beta-blockade was the dominating one. Symptoms of chest pain, dyspnea, claudicatio, smoking habits and working capacity did not differ and neither did quality of life according to the Nottingham Health Profile. We thus conclude that morbidity and quality of life were not significantly affected 5 years after early intervention with metoprolol in patients with suspected acute myocardial infarction.
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| 11. |
- Holmberg, Jonas, 1976-, et al.
(författare)
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Machining of additively manufactured alloy 718 in as-built and heat-treated condition: surface integrity and cutting tool wear
- 2024
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Ingår i: The International Journal of Advanced Manufacturing Technology. - : Springer Nature. - 0268-3768 .- 1433-3015. ; 130:3-4, s. 1823-1842
-
Tidskriftsartikel (refereegranskat)abstract
- Additive manufacturing (AM) using powder bed fusion is becoming a mature technology that offers great possibilities and design freedom for manufacturing of near net shape components. However, for many gas turbine and aerospace applications, machining is still required, which motivates further research on the machinability and work piece integrity of additive-manufactured superalloys. In this work, turning tests have been performed on components made with both Powder Bed Fusion for Laser Beam (PBF-LB) and Electron Beam (PBF-EB) in as-built and heat-treated conditions. The two AM processes and the respective heat-treatments have generated different microstructural features that have a great impact on both the tool wear and the work piece surface integrity. The results show that the PBF-EB components have relatively lower geometrical accuracy, a rough surface topography, a coarse microstructure with hard precipitates and low residual stresses after printing. Turning of the PBF-EB material results in high cutting tool wear, which induces moderate tensile surface stresses that are balanced by deep compressive stresses and a superficial deformed surface that is greater for the heat-treated material. In comparison, the PBF-LB components have a higher geometrical accuracy, a relatively smooth topography and a fine microstructure, but with high tensile stresses after printing. Machining of PBF-LB material resulted in higher tool wear for the heat-treated material, increase of 49%, and significantly higher tensile surface stresses followed by shallower compressive stresses below the surface compared to the PBF-EB materials, but with no superficially deformed surface. It is further observed an 87% higher tool wear for PBF-EB in as-built condition and 43% in the heat-treated condition compared to the PBF-LB material. These results show that the selection of cutting tools and cutting settings are critical, which requires the development of suitable machining parameters that are designed for the microstructure of the material.
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| 12. |
- Larsson, Johan P., et al.
(författare)
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Location choices of graduate entrepreneurs
- 2017
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Ingår i: Research Policy. - : Elsevier. - 0048-7333 .- 1873-7625. ; 46:8, s. 1490-1504
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Tidskriftsartikel (refereegranskat)abstract
- We review complementary theoretical perspectives on location choices of university graduate entrepreneurs derived from the individual-opportunity nexus and local embeddedness perspectives on entrepreneurship. Analysis of the full population of 215,388 graduates from Swedish institutions of higher education between 2002 and 2006 provides support for both location choice perspectives. Overall, 63% of graduate entrepreneurs start businesses locally in their region of graduation while 37% start businesses elsewhere. The likelihood of starting locally is substantially higher in metropolitan regions, if the graduate was born locally or has university peer entrepreneurs and entrepreneurial family members in the region of graduation. Implications for theory and public policy are discussed.
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| 13. |
- Lindberg, Johan, et al.
(författare)
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The Mitochondrial and Autosomal Mutation Landscapes of Prostate Cancer
- 2013
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Ingår i: European Urology. - : Elsevier BV. - 0302-2838 .- 1873-7560. ; 63:4, s. 702-708
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Tidskriftsartikel (refereegranskat)abstract
- Background: Prostate cancer (PCa) is the most common cancer in men. PCa is strongly age associated; low death rates in surveillance cohorts call into question the widespread use of surgery, which leads to overtreatment and a reduction in quality of life. There is a great need to increase the understanding of tumor characteristics in the context of disease progression. Objective: To perform the first multigenome investigation of PCa through analysis of both autosomal and mitochondrial DNA, and to integrate exome sequencing data, and RNA sequencing and copy-number alteration (CNA) data to investigate how various different tumor characteristics, commonly analyzed separately, are interconnected. Design, setting, and participants: Exome sequencing was applied to 64 tumor samples from 55 PCa patients with varying stage and grade. Integrated analysis was performed on a core set of 50 tumors from which exome sequencing, CNA, and RNA sequencing data were available. Outcome measurements and statistical analysis: Genes, mutated at a significantly higher rate relative to a genomic background, were identified. In addition, mitochondrial and autosomal mutation rates were correlated to CNAs and proliferation, assessed as a cell cycle gene expression signature. Results and limitations: Genes not previously reported to be significantly mutated in PCa, such as cell division cycle 27 homolog (Saccharomyces cerevisiae) (CDC27), myeloid/lymphoid or mixed-lineage leukemia 3 (MLL3), lysine (K)-specific demethylase 6A (KDM6A), and kinesin family member 5A (KIF5A) were identified. The mutation rate in the mitochondrial genome was 55 times higher than that of the autosomes. Multilevel analysis demonstrated a tight correlation between high reactive-oxygen exposure, chromosomal damage, high proliferation, and in parallel, a transition from multiclonal indolent primary PCa to monoclonal aggressive disease. As we only performed targeted sequence analysis; copy-number neutral rearrangements recently described for PCa were not accounted for. Conclusions: The mitochondrial genome displays an elevated mutation rate compared to the autosomal chromosomes. By integrated analysis, we demonstrated that different tumor characteristics are interconnected, providing an increased understanding of PCa etiology. (C) 2012 European Association of Urology. Published by Elsevier B. V. All rights reserved.
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| 14. |
- Westelius, Carl-Johan, et al.
(författare)
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Phase-based Disparity Estimation
- 1995
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Ingår i: Vision as Process. - Berlin : Springer-Verlag. - 354058143X - 038758143X ; , s. 157-178
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The problem of estimating depth information from two or more images of a scene is one which has received considerable attention over the years and a wide variety of methods have been proposed to solve it [Barnard and Fichsler, 1982; Fleck, 1991]. Methods based on correlation and methods using some form of feature matching between the images have found most widespread use. Of these, the latter have attracted increasing attention since the work of Marr [Marr, 1982], in which the features are zero-crossings on varying scales. These methods share an underlying basis of spatial domain operations.In recent years, however, increasing interest has been shown in computational models of vision based primarily on a localized frequency domain representation - the Gabor representation [Gabor, 1946; Adelson and Bergen, 1985], first suggested in the context of computer vision by Granlund [Granlund, 1978].
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| 15. |
- Westelius, Carl-Johan, et al.
(författare)
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Prototyping, Visualization and Simulation Using the Application Visualization System
- 1994
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Ingår i: Experimental Environments for Computer Vision and Image Processing. - Singapore : World Scientific Publishing Co. Pte. Ltd.. - 981021510X ; , s. 33-62
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The Application Visualization System software from Advanced Visual Systems Inc is an interactive visualization environment for scientists, engineers and technical professionals. This report contains a short overview of the AVS software packages and a discussion about its general performance. The software package has actively been used at the Computer Vision Laboratory, Linköping University, during the last three years. The AVS package has been used in many applications. Examples are generating images from a virtual environment, simulation of a controllable robot with a stereo camera head and visualization of multidimensional data structures. Lately we also have used AVS for handling communication between different processes which may be distributed on different machines. AVS was primarily developed as a tool for visualization of complex data sets. However, another important aspect of the software is that it can be used as an advanced workbench for controlling networks of Unix processes (including external ones on different machine types) using simple visual programming.
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| 16. |
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| 17. |
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| 18. |
- Wiklund, Johan A., et al.
(författare)
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A comparative study of UVP and LDA techniques for pulp suspensions in pipe flow
- 2006
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Ingår i: AIChE Journal. - : Wiley. - 0001-1541 .- 1547-5905. ; 52:2, s. 484-495
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Tidskriftsartikel (refereegranskat)abstract
- For the first time, noninvasive measurements in pulp suspensions at consistencies ranging from 0.74%(w/w) up to 7.8%(w/w) have been performed simultaneously using ultrasound velocity profiling (UVP) and laser doppler anemometry (LDA) in an experimental pipe flow loop. Results show that both techniques can be used to determine the plug flow velocity with good agreement in much more concentrated pulp suspensions than what has been reported so far in the literature. Instantaneous velocity profiles have been obtained noninvasively in pipe flow using the UVP technique, and it is shown that combined with simultaneous pressure drop measurements, the UVP technique can be used to determine the yield stress in-line. Results further show that LDA works, with limited penetration depth of up to several millimeters, even in strongly opaque systems, such as in 7.8%(w/w) pulp. Deviating results were however obtained in the near wall region and more work is needed.
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| 19. |
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| 20. |
- Wiklund, Johan, et al.
(författare)
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Hierarchical Phase Based Disparity Estimation
- 1992
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Ingår i: Proceedings of 2nd Singapore International Conference on Image Processing. - Linköping, Sweden : Linköping University, Department of Electrical Engineering. - 9789810211820 - 9810211821
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Rapport (övrigt vetenskapligt/konstnärligt)
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| 21. |
- Wiklund, Susanne, et al.
(författare)
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Visualization of GC/TOF-MS-based metabolomics data for identification of biochemically interesting compounds using OPLS class models
- 2008
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Ingår i: Analytical Chemistry. - Columbus, OH : American Chemical Society. - 0003-2700 .- 1520-6882. ; 80:1, s. 115-22
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Tidskriftsartikel (refereegranskat)abstract
- Metabolomics studies generate increasingly complex data tables, which are hard to summarize and visualize without appropriate tools. The use of chemometrics tools, e.g., principal component analysis (PCA), partial least-squares to latent structures (PLS), and orthogonal PLS (OPLS), is therefore of great importance as these include efficient, validated, and robust methods for modeling information-rich chemical and biological data. Here the S-plot is proposed as a tool for visualization and interpretation of multivariate classification models, e.g., OPLS discriminate analysis, having two or more classes. The S-plot visualizes both the covariance and correlation between the metabolites and the modeled class designation. Thereby the S-plot helps identifying statistically significant and potentially biochemically significant metabolites, based both on contributions to the model and their reliability. An extension of the S-plot, the SUS-plot (shared and unique structure), is applied to compare the outcome of multiple classification models compared to a common reference, e.g., control. The used example is a gas chromatography coupled mass spectroscopy based metabolomics study in plant biology where two different transgenic poplar lines are compared to wild type. By using OPLS, an improved visualization and discrimination of interesting metabolites could be demonstrated.
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| 22. |
- Achtenhagen, Leona, 1969-, et al.
(författare)
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How Companies Manage Resources For Firm Expansion
- 2006
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Ingår i: Paper presented at the Strategic Management Society Annual International Conference, Vienna, Austria, February 2006.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 23. |
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| 24. |
- Ackerley, Rochelle, 1980, et al.
(författare)
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Differential effects of radiant and mechanically applied thermal stimuli on human C-tactile afferent firing patterns.
- 2018
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Ingår i: Journal of neurophysiology. - : American Physiological Society. - 1522-1598 .- 0022-3077. ; 120:4, s. 1885-1892
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Tidskriftsartikel (refereegranskat)abstract
- C-tactile (CT) afferents respond to gentle tactile stimulation, but only a handful of studies in humans and animals have investigated whether their firing is modified by temperature. We describe the effects of radiant thermal stimuli, and of stationary and very slowly moving mechanothermal stimuli, on CT afferent responses. We find that CT afferents are primarily mechanoreceptors, as they fired little during radiant thermal stimuli, but they exhibited different patterns of firing during combined mechano-cool stimulation compared with warming. CTs fired optimally to gentle, very slowly moving, or stationary mechanothermal stimuli delivered at neutral temperature (~32°C, normal skin temperature), but they responded with fewer spikes (median 67% decrease) and at significantly lower rates (47% decrease) during warm (~42°C) tactile stimuli. During cool tactile stimuli (~18°C), their mean instantaneous firing frequency significantly decreased by 35%, but they often fired a barrage of afterdischarge spikes at a low frequency (~5 Hz) that outlasted the mechanical stimulus. These effects were observed under a variety of stimulus conditions, including during stationary and slowly moving touch (0.1 cm/s), and we complemented these tactile approaches using a combined electrical-thermal stimulation experiment where we found a suppression of spiking during warming. Overall, CT afferents are exquisitely sensitive to tactile events, and we show that their firing is modulated with touch temperatures above and below neutral skin temperature. Warm touch consistently decreased their propensity to fire, whereas cool touch produced lower firing rates but afterdischarge spiking. NEW & NOTEWORTHY C-tactile (CT) afferents are thought to underpin pleasant touch, and previous work has shown that they respond optimally to a slow caress delivered at typical (neutral) skin temperature. Here, we show that, although CTs are primarily mechanoreceptive afferents, they are modified by temperature: warm touch decreases their firing, whereas cool touch produces lower firing rates but long-lasting spiking, frequently seen as afterdischarges. This has implications for the encoding of affective sensory events in human skin.
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| 25. |
- Almby, Kristina E., et al.
(författare)
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Effects of Gastric Bypass Surgery on the Brain : Simultaneous Assessment of Glucose Uptake, Blood Flow, Neural Activity, and Cognitive Function During Normo- and Hypoglycemia
- 2021
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 70:6, s. 1265-1277
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Tidskriftsartikel (refereegranskat)abstract
- While Roux-en-Y gastric bypass (RYGB) surgery in obese individuals typically improves glycemic control and prevents diabetes, it also frequently causes asymptomatic hypoglycemia. Previous work showed attenuated counterregulatory responses following RYGB. The underlying mechanisms as well as the clinical consequences are unclear. In this study, 11 subjects without diabetes with severe obesity were investigated pre- and post-RYGB during hyperinsulinemic normo-hypoglycemic clamps. Assessments were made of hormones, cognitive function, cerebral blood flow by arterial spin labeling, brain glucose metabolism by F-18-fluorodeoxyglucose (FDG) positron emission tomography, and activation of brain networks by functional MRI. Post- versus presurgery, we found a general increase of cerebral blood flow but a decrease of total brain FDG uptake during normoglycemia. During hypoglycemia, there was a marked increase in total brain FDG uptake, and this was similar for post- and presurgery, whereas hypothalamic FDG uptake was reduced during hypoglycemia. During hypoglycemia, attenuated responses of counterregulatory hormones and improvements in cognitive function were seen postsurgery. In early hypoglycemia, there was increased activation post- versus presurgery of neural networks in brain regions implicated in glucose regulation, such as the thalamus and hypothalamus. The results suggest adaptive responses of the brain that contribute to lowering of glycemia following RYGB, and the underlying mechanisms should be further elucidated.
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| 26. |
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| 27. |
- Amezcua, Alejandro, et al.
(författare)
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Organizational sponsorship and founding environments : A contingency view on the survival of business incubated firms, 1994-2007
- 2013
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Ingår i: Academy of Management Journal. - : Academy of Management. - 0001-4273 .- 1948-0989. ; 56:6, s. 1628-1654
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Tidskriftsartikel (refereegranskat)abstract
- Organizational sponsorship mediates the relationship between new organizations and their environments by creating a resource-munificent context intended to increase survival rates among those new organizations. Existing theories are prone to treat such resource munificence as the inverse of resource dependence, indicating that the application of new resources in an entrepreneurial context should always benefit new firms. These existing theories, however, often overlook heterogeneity in both types of applied resources as well as founding environmental conditions. By attending to these nuances, we reveal that resource munificence is not necessarily predictive of organizational survival. We find that resource munificence related to sponsorship can potentially decrease or increase survival rates among new organizations and that these effects are contingent on fit of resource type with its respective geographic-based founding density. These findings confirm the need for a more-nuanced theory of sponsorship that attends to the mechanisms and conditions by which resource munificence is likely to alter new organization survival rates.
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| 28. |
- Andersson, Johan, et al.
(författare)
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Male sex pheromone release and female mate choice in a butterfly
- 2007
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 210:6, s. 964-970
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Tidskriftsartikel (refereegranskat)abstract
- In butterflies female mate choice is influenced by both visual and olfactory cues, the latter of which are important at close range. Males of the green-veined butterfly, Pieris napi, are known to release citral ( mixture of geranial and neral, 1: 1), but its role(s) and conditions of release are not known. Here, we show that male P. napi release citral when interacting with conspecific males, conspecific females, heterospecific males and also when alone. The amount of citral released correlated strongly with male flight activity, which explained more than 70% of the variation. This suggests that males do not exercise control over turning release on or off, but rather that citral is emitted as a passive physical process during flight. Electroantennogram experiments showed that female antennal response was ten times more sensitive to citral than male response. Females expressed acceptance behavior when exposed to models made with freshly excised male wings or those treated with citral following chemical extraction, but not to ones with extracted wings only. Hence, these behavioral and electrophysiological tests provide strong evidence that citral is a signal from the male directed to the female during courtship, and that it functions as a male sex pheromone.
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| 29. |
- Andersson, Johan, et al.
(författare)
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Sexual conflict and anti-aphrodisiac titre in a polyandrous butterfly : male ejaculate tailoring and absence of female control
- 2004
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 271:1550, s. 1765-1770
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Tidskriftsartikel (refereegranskat)abstract
- Males of the green-veined butterfly Pieris napi synthesize and transfer the volatile methyl salicylate (MeS) to females at mating, a substance that is emitted by non-virgin females when courted by males, curtailing courtship and decreasing the likelihood of female re-mating. The volatile is released when females display the 'mate-refusal' posture with spread wings and elevated abdomen, when courted by conspecific males. Here, we assess how the amount of MeS released by courted females changes over time since mating, and whether it is influenced by the frequency with which females display the mate-refusal posture. We also assess whether males tailor the anti-aphrodisiac content of ejaculates with respect to the expected degree of sperm competition, by comparing how males allocate MeS proportionately to first and second ejaculates in relation to ejaculate mass. The results show that females housed for 5 days in individual cages where they were able to fly and oviposit normally, released similar amounts of MeS. However, females housed together for the same period of time, causing them to frequently display the mate-refusal posture, released significantly lower levels of MeS than the individually housed females. This indicates that female display of the mate-refusal posture depletes their anti-aphrodisiac stores, and suggests that females are unable to voluntarily control their release of the anti-aphrodisiac. A comparison of relative proportion of MeS transferred by males in their first and second ejaculates showed that proportionately more MeS was allocated to the first ejaculate, in accordance with the idea that these are tailored to delay female re-mating.
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| 30. |
- Andersson, Mats, et al.
(författare)
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Filter Networks
- 1999
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Ingår i: Proceedings of Signal and Image Processing (SIP'99). - Nassau, Bahamas : IASTED. - 0889862672 ; , s. 213-217
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Konferensbidrag (refereegranskat)abstract
- This paper presents a new and efficient approach for optimization and implementation of filter banks e.g. velocity channels, orientation channels and scale spaces. The multi layered structure of a filter network enable a powerful decomposition of complex filters into simple filter components and the intermediary results may contribute to several output nodes. Compared to a direct implementation a filter network uses only a fraction of the coefficients to provide the same result. The optimization procedure is recursive and all filters on each level are optimized simultaneously. The individual filters of the network, in general, contain very few non-zero coefficients, but there are are no restrictions on the spatial position of the coefficients, they may e.g. be concentrated on a line or be sparsely scattered. An efficient implementation of a quadrature filter hierarchy for generic purposes using sparse filter components is presented.
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| 31. |
- Andersson, Mats, et al.
(författare)
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Sequential Filter Trees for Efficient 2D 3D and 4D Orientation Estimation
- 1998
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A recursive method to condense general multidimensional FIR-filters into a sequence of simple kernels with mainly one dimensional extent has been worked out. Convolver networks adopted for 2, 3 and 4D signals is presented and the performance is illustrated for spherically separable quadrature filters. The resulting filter responses are mapped to a non biased tensor representation where the local tensor constitutes a robust estimate of both the shape and the orientation (velocity) of the neighbourhood. A qualitative evaluation of this General Sequential Filter concept results in no detectable loss in accuracy when compared to conventional FIR (Finite Impulse Response) filters but the computational complexity is reduced several orders in magnitude. For the examples presented in this paper the attained speed-up is 5, 25 and 300 times for 2D, 3D and 4D data respectively The magnitude of the attained speed-up implies that complex spatio-temporal analysis can be performed using standard hardware, such as a powerful workstation, in close to real time. Due to the soft implementation of the convolver and the tree structure of the sequential filtering approach the processing is simple to reconfigure for the outer as well as the inner (vector length) dimensionality of the signal. The implementation was made in AVS (Application Visualization System) using modules written in C.
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| 32. |
- Andersson, Thord, et al.
(författare)
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WITAS Project at Computer Vision Laboratory; A status report (Jan 1998)
- 1998
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Ingår i: Proceedings of the SSAB symposium on image analysis. ; , s. 113-116
-
Konferensbidrag (refereegranskat)abstract
- WITAS will be engaged in goal-directed basic research in the area of intelligent autonomous vehicles and other autonomous systems. In this paper an overview of the project is given together with a presentation of our research interests in the project. The current status of our part in the project is also given.
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| 33. |
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| 34. |
- Arvanitis, Leena, et al.
(författare)
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Butterfly seed predation: effects of landscape characteristics, plant ploidy level and population structure
- 2007
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Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 152:2, s. 275-285
-
Tidskriftsartikel (refereegranskat)abstract
- Polyploidization has been suggested as one of the most common mechanisms for plant diversification. It is often associated with changes in several morphological, phenological and ecological plant traits, and therefore has the potential to alter insect–plant interactions. Nevertheless, studies evaluating the effect of plant polyploidy on interspecific interactions are still few. We investigated pre-dispersal seed predation by the butterfly Anthocharis cardamines in 195 populations of two ploidy levels of the herb Cardamine pratensis (tetraploid ssp. pratensis, 2n = 30 vs. octoploid ssp. paludosa, 2n = 56–64). We asked if differences in incidence and intensity of predation among populations were related to landscape characteristics, plant ploidy level and population structure. The incidence of the seed predator increased with increasing plant population size and decreasing distance to nearest population occupied by A. cardamines. The intensity of predation decreased with increasing plant population size and was not affected by isolation. Probability of attack decreased with increasing shading, and intensity of predation was higher in grazed than in non-grazed habitats. The attack intensity increased with increasing mean flower number of plant population, but was not affected by flowering phenology. Individuals in tetraploid populations suffered on average from higher levels of seed predation, had higher mean flower number, were less shaded and occurred more often in grazed habitats than octoploid populations. When accounting for differences in habitat preferences between ploidy levels there was no longer a difference in intensity of predation, suggesting that the observed differences in attack rates among populations of the two ploidy levels are mediated by the habitat. Overall, our results suggest that polyploidization is associated with differentiation in habitat preferences and phenotypic traits leading to differences in interspecific interaction among plant populations. This, in turn, may facilitate further divergence of ploidy levels.
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| 35. |
- Arvanitis, Leena, et al.
(författare)
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Plant ploidy level influences selection by butterfly seed predators
- 2008
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Ingår i: Oikos. ; 117, s. 1020-1025
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Tidskriftsartikel (refereegranskat)abstract
- Polyploidization is a common route to plant diversification. Polyploids often differ from their progenitors in size, flower number, flower size and flowering phenology. Such differences may translate into differences in the intensity of interactions with animals. Here we investigated the impact of the ploidy-related differences in tetraploids and octoploids of the perennial herb Cardamine pratensis on pre-dispersal seed predation by the butterfly Anthocharis cardamines. The probability of escaping attack was lower for octoploids than for tetraploids, even after accounting for the fact that octoploids were larger and had fewer flowers than tetraploids. Flower shoot size was correlated with probability of attack in tetraploids but not in octoploids. Differences in plant traits associated with polyploidization can alter interactions with animals, and animal-mediated differences in trait selection between ploidy types can contribute to their further divergence.
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| 36. |
- Arvanitis, Leena, 1959-
(författare)
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Plant polyploidy and interactions with insect herbivores
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Polyploidization has been suggested to be a common mechanism for plant speciation. Polyploidy is associated with changes in plant traits and altered habitat preference. Antagonistic and mutualistic animals are known to discriminate between plants based on variation in such plant traits, suggesting that interactions may have an important role in divergence of plant polyploids after the polyploidization. In this thesis, I investigated the effect of insect herbivores on divergence of plant polyploids in a system consisting of the predispersal seed predator butterfly Anthocharis cardamines, the bud gall forming midge Dasineura cardaminis, and tetraploids and octoploids of the herb Cardamine pratensis. Octoploid populations occurred more often in shaded and nongrazed habitats than tetraploids. Octoploid plants were larger and had fewer but larger flowers than tetraploids. Butterfly attack rates were higher in tetraploid than in octoploid populations, whereas the gall midge attacked only octoploids. These differences were associated with higher abundance of butterflies in sunny habitats and gall midges in shaded habitats. In contrast to the pattern at the population level, octoploid flower shoots were more likely to be attacked by the butterfly in sympatric populations. Also trait selection differed between ploidy levels, both in the absence and in the presence of herbivores. In a field experiment, butterfly preference did not alter the trait selection in tetraploids. In octoploids, the two herbivores did not change selection considered separately. However, their joint effect resulted in significant selection for smaller flower shoots and reduced selection on number of flowers. This thesis demonstrates that differences in habitat preference and phenotypic plant traits between polyploid cytotypes can lead to altered interactions with herbivores. Such differences in interactions with animals may alter not only the relative fitness of cytotypes but also trait selection within the respective ploidy type.
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| 37. |
- Axén, Elin, et al.
(författare)
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Degree of Preservation of Neurovascular Bundles in Radical Prostatectomy and Recurrence of Prostate Cancer
- 2021
-
Ingår i: European Urology Open Science. - : Elsevier BV. - 2666-1691 .- 2666-1683. ; 30, s. 25-33
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Reports on possible benefits for continence with nerve-sparing (NS) radical prostatectomy have expanded the indications beyond preservation of erectile function. It is unclear whether NS surgery affects oncological outcomes. Objective: To determine whether the degree of NS during radical prostatectomy influences oncological outcomes. Design, setting, and participants: Of 4003 patients enrolled in a prospective, controlled trial comparing open and robotic radical prostatectomy during 2008–2011, we evaluated 2401 patients who received robotic radical prostatectomy at seven Swedish centres. Patients were followed for 8 yr. Outcome measurements and statistical analysis: Data for recurrence and positive surgical margin status were assessed using validated patient questionnaires, patient interviews, and clinical record forms before and at 3, 12, and 24 mo and 6 and 8 yr after surgery. Cox and logistic regressions were used to model the effect on recurrence and positive surgical margins (PSM), respectively. Results and limitations: A total of 481 men had PSM and 467 experienced recurrence during follow-up. Median follow-up for men without recurrence was 6.6 yr. There were no statistically significant differences in recurrence rate between degrees of NS. The PSM rate was significantly higher with a higher degree of NS: interfascial NS, odds ratio (OR) 2.32 (95% confidence interval [CI] 1.69–3.16); intrafascial NS, OR 3.23 (95% CI 2.17–4.80). Recurrence rates were higher for patients with pT2 disease and PSM (hazard ratio [HR] 3.32, 95% CI 2.43–4.53) than for patients with pT3 disease without PSM (HR 2.08, 95% CI 1.66–2.62). The lack of central review of pathological specimens is a limitation. Conclusions: A higher degree of NS significantly increased the risk of PSM but did not significantly increase the risk of cancer recurrence. Combined with the known functional benefits of NS surgery, these results underscore the need to identify an individualised balance. Patient summary: In this report we looked at the effect of a nerve-sparing approach during removal of the prostate on cancer outcomes for patients having robot-assisted surgery at seven Swedish hospitals. We found that a high degree of nerve-sparing increased the rate of cancer positivity at the margins of surgical specimens and that positive surgical margins increased the risk of recurrence of prostate cancer. © 2021 The Authors
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| 38. |
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| 39. |
- Bankel, Johan, 1959, et al.
(författare)
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Benchmarking engineering curricula with the CDIO syllabus
- 2005
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Ingår i: International Journal of Engineering Education. - 0949-149X. ; 21:1, s. 121-133
-
Tidskriftsartikel (refereegranskat)abstract
- Four internationally-renowned universities-Chalmers University of Technology, Linkoping University, Royal Institute of Technology (Sweden), and the Massachusetts Institute of Technology (USA)-developed a benchmark survey that may be used by any engineering school to benchmark curricula for teaching of personal, interpersonal and system building skills. These skills are enumerated in the CDIO Syllabus. Teaching activities were categorized as Introduce, Teach or Utilize, based on intent, time spent, and linkage to learning objectives, assignments and assessment criteria. Interviews were used to collect the data from instructors of the schools' engineering programs. The data was then reduced and analyzed to illuminate patterns of teaching. The results indicate that much effort is expended in covering these topics, but often in an inefficient, uncoordinated and unplanned manner. For example, there are often frequent repetitions of introducing a topic, without ever teaching it. In other instances, students are expected to utilize knowledge without having been taught it. The results of the benchmark survey indicate that a consistent and deliberately designed curriculum in this area could demand no additional resources, yet provide a much more effective education. The survey gives useful indications of how to begin such a curriculum redesign process.
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| 40. |
- Bankel, Johan, et al.
(författare)
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The CDIO syllabus: a comparative study of expected student proficiency
- 2003
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Ingår i: European Journal of Engineering Education. - : Taylor & Francis. - 0304-3797 .- 1469-5898. ; 28:3, s. 297-315
-
Tidskriftsartikel (refereegranskat)abstract
- Engineering students must graduate with command of a vast body of technical knowledge. They must possess personal, interpersonal and system-building skills to function in teams, and be prepared to produce products and systems. Their education must have been structured under a curriculum blending ability to combine technical expertise with ethical, innovative, philosophical and humanistic acumen. This paper describes a unique international collaboration among four universities to reform engineering education. The collaborators agreed to a statement of goals, which includes descriptions of knowledge, skills and attitudes vital to an effective education, and codifies proficiency levels expected of graduates. We developed and utilized unique stakeholder surveys both to validate our prototype and to determine desired proficiency levels. This collaboration resulted in The CDIO Syllabus, A Statement of Goals for Undergraduate Engineering Education. The syllabus is both a template and a process that can be used to customize the syllabus to others' programmes. It can define new educational initiatives/and be employed as the basis for rigorous assessment. This paper details how, with the input of industry, academia and others, we employed an engineering problem-solving paradigm to effect our redesign. It outlines the syllabus and the unique process employed to create it.
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| 41. |
- Bartha, Erzsebet, et al.
(författare)
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Performance of prediction models of postoperative mortality in high-risk surgical patients in swedish university hospitals : Predictors, Risk factors and Outcome Following major Surgery study (PROFS study NCT02626546)
- 2017
-
Ingår i: Acta Anaesthesiologica Scandinavica. - : John Wiley & Sons. - 0001-5172 .- 1399-6576. ; 61:8, s. 1056-1057
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background: There are several progn ostic prediction models that estimate the probability of postoperative mortality. The role of these models is to support clinical decisions. Before implementation of a prediction model in routine care, it is necessary to analyze its performance in the target population. Our aim was to analyze the performance of four different prediction models of postoperative mortality in a high-risk surgical population.Methods: Data collected from 2015-11-01 until 2016-02-15 in a prospective consecutive observational study (PROFS study) in four university hospitals was used. The inclusion criteria were adult, ASA classification ≥3, and major/complex upper or lower gastrointestinal, urogenital or orthoped ic surgery (UK surgical severity codingA XA PPP). Four prediction models were evaluated: Surgical Outcome Risk Tool (SORT), Surgical APGAR, P-POSSUM and Surgical Risk Scale (SRS). The outcome measure was 90-day mortality. We evaluated the discrimination of the models by area under receiver operator characteristic curve (AUC ROC) before and after recalibration.Results: In total, 1 089 patients were included. Thirteen patients were excluded due to erroneous inclusion, and another three were lost to follow-up, so data from 1 073 was used in this analysis. The mean age was 73 years, the presence of malignancy was 41%, and 90-day mortality was 13% (n = 140). The SORT model had the best discrimination both before and after recalibration. The P-POSSUM model improved after recalibration. The SRS model overestimated, whereas the APGAR model underestimated, the risk of mortality.Conclusions: The original SORT model is promising and could be incorporated as decision support for high-risk surgical patients.
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| 42. |
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| 43. |
- Berglund, Johan C, 1978, et al.
(författare)
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A Method for Visualization of Surface Texture Anisotropy in Different Scales of Observation
- 2011
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Ingår i: Scanning. - : John Wiley & Sons. - 0161-0457 .- 1932-8745. ; 33:5, s. 325-331
-
Tidskriftsartikel (refereegranskat)abstract
- Anisotropy of functional surfaces can in many practical cases significantly influence the surface function. Tribological contacts in sheet forming and engine applications are good examples. This article introduces and exemplifies a method for visualization of anisotropy. In a single graph, surface texture properties related to the anisotropy as a function of scale are plotted. The anisotropy graph can be used to explain anisotropy properties of a studied surface such as texture direction and texture strength at different scales of observation. Examples of milled steel surfaces and a textured steel sheet surface are presented to support the proposed methodology. Different aspects of the studied surfaces could clearly be seen at different scales. Future steps to improve filtering techniques and an introduction of length-scale analysis are discussed.
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| 44. |
- Berta, M., et al.
(författare)
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Correlation between in-line measurements of tomato ketchup shear viscosity and extensional viscosity
- 2016
-
Ingår i: Journal of Food Engineering. - : Elsevier BV. - 0260-8774 .- 1873-5770. ; 173, s. 8-14
-
Tidskriftsartikel (refereegranskat)abstract
- The viscosity and shear thinning behavior are essential characteristics of tomato ketchup. A real-time monitoring of those characteristics during processing is important to obtain a good quality of the final product and to reduce production waste. This work investigates the measurement of rheological in-line flow properties of tomato ketchup, using a real-time technique that combines ultrasound velocity profiling (UVP) and pressure difference (PD) assessment. In-line data were compared to those obtained off-line using a rotational viscometer. There was a poor correlation with the Bostwick measurement, whereas the flow curves calculated from flow velocimetry data were very similar to those measured off-line. The extensional viscosity of ketchup was determined through the measurement of Hyperbolic Contraction Flow; the curve followed a trend similar to that for the shear viscosity over the deformation rate investigated.
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| 45. |
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| 46. |
- Bigun, Josef, et al.
(författare)
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Multidimensional orientation estimation with applications to texture analysis and optical flow
- 1991
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Ingår i: IEEE Transactions on Pattern Analysis and Machine Intelligence. - : Institute of Electrical and Electronics Engineers (IEEE). - 0162-8828 .- 1939-3539. ; 13:8, s. 775-790
-
Tidskriftsartikel (refereegranskat)abstract
- The problem of detection of orientation in finite dimensional Euclidean spaces is solved in the least squares sense. In particular, the theory is developed for the case when such orientation computations are necessary at all local neighborhoods of the n-dimensional Euclidean space. Detection of orientation is shown to correspond to fitting an axis or a plane to the Fourier transform of an n-dimensional structure. The solution of this problem is related to the solution of a well-known matrix eigenvalue problem. Moreover, it is shown that the necessary computations can be performed in the spatial domain without actually doing a Fourier transformation. Along with the orientation estimate, a certainty measure, based on the error of the fit, is proposed. Two applications in image analysis are considered: texture segmentation and optical flow. An implementation for 2-D (texture features) as well as 3-D (optical flow) is presented. In the case of 2-D, the method exploits the properties of the complex number field to by-pass the eigenvalue analysis, improving the speed and the numerical stability of the method. The theory is verified by experiments which confirm accurate orientation estimates and reliable certainty measures in the presence of noise. The comparative results indicate that the proposed theory produces algorithms computing robust texture features as well as optical flow. The computations are highly parallelizable and can be used in realtime image analysis since they utilize only elementary functions in a closed form (up to dimension 4) and Cartesian separable convolutions.
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| 47. |
- Bill-Axelson, Anna, 1965-
(författare)
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Localized Prostate Cancer : Results From a Randomized Clinical Trial
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aims of the thesis were to• explore whether radical prostatectomy is beneficial compared with watchful waiting in survival and disease progression• find possible effect modifiers• evaluate a protocol of multiple biopsies and investigate if men with previous benign prostate biopsies are a group at risk for later prostate cancer• inquire into patients’ and clinicians’ experiences of randomization in order to find out what made this study possible to conduct, and thereby contribute to improve randomization in the futureThe background material was a large randomized clinical trial, the Scandinavian Prostatic Cancer Group Study Number 4, or SPCG-4, which was open for inclusion from February 1989 through December 1999. It comprised 695 men in Sweden, Finland and Iceland who had localized prostate cancer and were randomized to either radical prostatectomy or watchful waiting. After a mean follow-up time of 6.2 years the first analyses, according to intention-to-treat, showed that radical prostatectomy reduced disease specific mortality, risk of metastases and risk of local progression but did not statistically significantly reduce overall mortality. The second analyses confirmed our earlier findings and furthermore, at ten years, radical prostatectomy also statistically significantly reduced overall mortality. Age appeared as an independent effect modifier that will be further investigated.A total of 547 men, with a suspicion of prostate cancer that had undergone multiple biopsies, and whose biopsies had benign histology were later compared with the background population to evaluate whether they were a group at risk of developing prostate cancer. Within six years of follow-up, there was no increased risk of prostate cancer.Patients as well as clinicians used individual strategies to cope with the situation. The randomizing clinician has to understand the patient’s strategy and his expectations in order to individualize the information accordingly.
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| 48. |
- Blombäck, Anna, et al.
(författare)
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The Risk-taking Behaviour of Rapid Growth SMEs
- 1999
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Ingår i: The Third International Stockholm Seminar on Risk Behaviour and Risk Management..
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 49. |
- Bock, David, 1976, et al.
(författare)
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Habits and self-assessed quality of life, negative intrusive thoughts and depressed mood in patients with prostate cancer: a longitudinal study
- 2017
-
Ingår i: Scandinavian Journal of Urology. - : Medical Journals Sweden AB. - 2168-1805 .- 2168-1813. ; 51:5, s. 353-359
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: The aim of this study was to evaluate the association of self-assessed preoperative physical activity, alcohol consumption and smoking with self-assessed quality of life, negative intrusive thoughts and depressed mood after radical prostatectomy.Materials and methods: The Laparoscopic Prostatectomy Robot Open (LAPPRO) trial was a prospective, controlled, non-randomized longitudinal trial of patients (n=4003) undergoing radical prostatectomy at 14 centers in Sweden. Validated patient questionnaires were collected at baseline, and 3, 12 and 24 months after surgery.Results: Preoperative medium or high physical activity or low alcohol consumption or non-smoking was associated with a lower risk of depressed mood. High alcohol consumption was associated with increased risk of negative intrusive thoughts. Postoperatively, quality of life and negative intrusive thoughts improved gradually in all groups. Depressed mood appeared to be relatively unaffected.Conclusions: Evaluation of preoperative physical activity, tobacco and alcohol consumption habits can be used to identify patients with a depressed mood in need of psychological support before and immediately after surgery. Quality of life and intrusive thoughts improved postoperatively.
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| 50. |
- Bock, David, 1976, et al.
(författare)
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Learning curve for robot-assisted laparoscopic radical prostatectomy in a large prospective multicentre study
- 2022
-
Ingår i: Scandinavian Journal of Urology. - : Medical Journals Sweden AB. - 2168-1805 .- 2168-1813. ; 56:3, s. 182-190
-
Tidskriftsartikel (refereegranskat)abstract
- Objective Differences in outcome after radical prostatectomy for prostate cancer can partly be explained by intersurgeon differences, where degree of experience is one important aspect. This study aims to define the learning curve of robot-assisted laparoscopic prostatectomy (RALP) regarding oncological and functional outcomes. Materials and methods Out of 4003 enrolled patients in the LAPPRO trial, 3583 met the inclusion criteria, of whom 885 were operated on by an open technique. In total, 2672 patients with clinically localized prostate cancer from seven Swedish centres were operated on by RALP and followed for 8 years (LAPPRO trial). Oncological outcomes were pathology-reported surgical margins and biochemical recurrence at 8 years. Functional outcomes included patient-reported urinary incontinence and erectile dysfunction at 3, 12 and 24 months. Experience was surgeon-reported experience before and during the study. The relationship between surgeon experience and functional outcomes and surgical margin status was analysed by mixed-effects logistic regression. Biochemical recurrence was analysed by Cox regression, with robust standard errors. Results The learning curve for positive surgical margins was relatively flat, with rates of 21% for surgeons who had performed 0-74 cases and 24% for surgeons with > 300 cases. Biochemical recurrence at 4 years was 11% (0-74 cases) and 13% (> 300 cases). Incontinence was stable over the learning curve, but erectile function improved at 2 years, from 38% (0-74 cases) to 53% (> 300 cases). Conclusions Analysis of the learning curve for surgeons performing RALP showed that erectile function improved with increasing number of procedures, which was not the case for oncological outcomes.
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