| 1. |
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| 2. |
- Bengmark, Samuel, 1965, et al.
(författare)
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Chalmersutbildning kan ge högre lärarstatus
- 2009
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Ingår i: Göteborgs Posten, Debatt, nätupplagan.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Läraryrket behöver en uppvärdering och stora pensionsavgångar samt svårigheter att konkurrera om studenter till lärarutbildningen kräver åtgärder och nytänkande. Chalmers vill därför starta ämneslärarutbildning i data, fysik, kemi, matematik och teknik så att studenten kan få både en lärarexamen och en ingenjörsexamen, skriver bland andra Samuel Bengmark, programansvarig för Chalmers lärarutbildning.
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| 3. |
- Bengmark, Samuel, 1965, et al.
(författare)
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Combining engineering and teacher education – ideas and experiences from Chalmers University of Technology
- 2021
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Ingår i: Bidrag från 8:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar. - 9789178672714
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Konferensbidrag (refereegranskat)abstract
- In response to the lack of STEM teachers in Sweden, Chalmers University of Technology offers a double degree program in engineering and education. This article investigates which ideas behind the program’s design have been of particular value in implementing the program and their added value. The five main ideas are: involve skilled schoolteachers called master teachers in the education, having many entrances to the program but only one exit, using interviews as part of the admission process, using a competency model to ensure coherence in the education, focusing on concrete work skills at the beginning of the education and later move on to theory and further development. We invite other universities to consider double degree programs in engineering and education and be inspired by these five ideas in their implementation.
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| 4. |
- Larsson, J., et al.
(författare)
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A developmentally descriptive method for quantifying shape in gastropod shells
- 2020
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Ingår i: Journal of the Royal Society Interface. - : The Royal Society. - 1742-5689 .- 1742-5662. ; 17:163
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Tidskriftsartikel (refereegranskat)abstract
- The growth of snail shells can be described by simple mathematical rules. Variation in a few parameters can explain much of the diversity of shell shapes seen in nature. However, empirical studies of gastropod shell shape variation typically use geometric morphometric approaches, which do not capture this growth pattern. Wehave developedaway toinfera setofdevelop-mentally descriptive shape parameters based on three-dimensional logarithmic helicospiral growth and using landmarks from two-dimensional shell images as input. We demonstrate the utility of this approach, and compare it to the geometric morphometric approach, using a large set of Littorina saxatilis shells in which locally adapted populations differ in shape. Our method can be modified easily to make it applicable to a wide range of shell forms, which would allow for investigations of the similarities and differences between and within many different species of gastropods. © 2020 The Authors.
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| 5. |
- Lundh, Torbjörn, 1965, et al.
(författare)
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Fermat Pedagogy – a method to help students make effective lecture notes
- 2018
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Ingår i: 6:e utvecklingskonferensen för Sveriges ingenjörsutbildningar Göteborg, 2017-11-22 - 2017-11-23, s. 61-65. ; , s. 61-65
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Konferensbidrag (refereegranskat)abstract
- We have developed and implemented a form of lecturing, which we call Fermat Pedagogy, that promotes analternative form of student note-taking. We did a comparative study in a basic calculus course if about 300 students randomly divided into two groups, one taught with Fermat Pedagogy and one control group. We used a diagnostic test and the final test to collect data. We report both the students thoughts about note-taking and also about the level of knowledge in both groups in the beginning andin the end of the course. The main three opinions about note-taking that we find in the students response are that note-taking help to keep focus, that the notes provide an shorter text and but that note-taking makes it harder to listen.The quantitative results indicates that Fermat Pedagogy can help the more motivated students to get a higher grade, but seem also have the effect that the weaker students do worse than they otherwise should have. These indications are not conclusive and need more studies to be verified. This may never the less make a foundation for a discussion on how we might look at our own lectures and how they are perceived, and documented, by our students.
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| 6. |
- Lundh, Torbjörn, 1965, et al.
(författare)
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Politiker missar på nytt det centrala
- 2014
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Ingår i: Svenska Dagbladet, Opinion, Brännpunkt 4 april 2014. - 1101-2412.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Läraruppdraget är en mycket komplex uppgift. Fokus måste därför ligga på att 1. göra läraryrket attraktivt så att vi lockar de mest drivna studenterna att söka sig till yrket, och 2. se till de som är verksamma som lärare rustas för att fungera i den komplexa rollen.
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| 7. |
- Aikawa, Hiroaki, 1956, et al.
(författare)
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MARTIN BOUNDARY FOR UNION OF CONVEX SETS
- 2002
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Ingår i: 京都大学数理解析研究所, Potential Theory and Related Topics. ; 1293, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- We study Martin boundary points of aproper subdomain in $\mathbb{R}^{n}$ , where $n$ $\geq 2$ , that can be represented as the union of open convex sets. Especially, we give acertain sufficient condition for aboundary point to have exactly one (minimal) Martin boundary point.
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| 8. |
- Aikawa, Hiroaki, 1956, et al.
(författare)
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Martin boundary of a fractal domain
- 2003
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Ingår i: Potential Analysis. - : Springer Science and Business Media LLC. - 0926-2601 .- 1572-929X. ; 18:4, s. 311-357
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Tidskriftsartikel (refereegranskat)abstract
- A uniformly John domain is a domain intermediate between a John domain and a uniform domain. We determine the Martin boundary of a uniformly John domain D as an application of a boundary Harnack principle. We show that a certain self-similar fractal has its complement as a uniformly John domain. In particular, the complement of the 3-dimensional Sierpinacuteski gasket is a uniform domain and its Martin boundary is homeomorphic to the Sierpinacuteski gasket itself.
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| 9. |
- Aikawa, Hiroaki, 1956, et al.
(författare)
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Martin boundary points of a John domain and unions of convex sets
- 2006
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Ingår i: J. Math. Soc. Japan. - 0025-5645 .- 1881-1167. ; 58:1, s. 247-274
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Tidskriftsartikel (refereegranskat)abstract
- We show that a John domain has finitely many minimal Martin boundary points at each Euclidean boundary point. The number of minimal Martin boundary points is estimated in terms of the John constant. In particular, if the John constant is bigger than $\sqrt3/2$ , then there are at most two minimal Martin boundary points at each Euclidean boundary point. For a class of John domains represented as the union of convex sets we give a sufficient condition for the Martin boundary and the Euclidean boundary to coincide.
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| 10. |
- Aikawa, Hiroaki, et al.
(författare)
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On boundary layers
- 1996
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Ingår i: Arkiv för matematik. ; 34:1
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Tidskriftsartikel (refereegranskat)
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| 11. |
- Aikawa, Hiroaki, 1956, et al.
(författare)
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On boundary layers
- 1996
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Ingår i: Arkiv för matematik. ; 34:1
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Tidskriftsartikel (refereegranskat)abstract
- https://projecteuclid.org/download/pdf_1/euclid.afm/1485898494
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| 12. |
- Aikawa, Hiroaki, 1956, et al.
(författare)
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The 3G inequality for a uniformly John domain
- 2005
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Ingår i: Kodai Mathematical Journal. ; 28:2, s. 209-219
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Tidskriftsartikel (refereegranskat)abstract
- Let G be the Green function for a domain D $\subset$ Rd with d ≥ 3. The Martin boundary of D and the 3G inequality: $\frac{G(x,y)G(y,z)}{G(x,z)} \le A(|x-y|^{2-d}+|y-z|^{2-d})$ for x,y,z $\in$ D are studied. We give the 3G inequality for a bounded uniformly John domain D, although the Martin boundary of D need not coincide with the Euclidean boundary. On the other hand, we construct a bounded domain such that the Martin boundary coincides with the Euclidean boundary and yet the 3G inequality does not hold.
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| 13. |
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| 14. |
- Baaz, Marcus, 1993, et al.
(författare)
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Population Modeling of Toxicological Combination Effects
- 2022
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Aim: Nonlinear mixed effects (NLME) modeling is currently the state-of-the-art mathematical framework for analyzing population data in medicine. We aim to illustrate how NLME modeling and the Tumor Static Exposure (TSE) concept can be beneficial for analyzing the effects of combined pollutants in marine life. Results: TSE is defined as all drug exposure that results in tumor stasis and therefore separates the space of all exposures into a region of tumor growth and a region of tumor shrinkage. TSE is derived from the equations of the NLME model and when two drugs are investigated the TSE for the median individual can be illustrated in a diagram with each axis representing the exposure of one of the drugs. We apply a similar approach to a toxicological model that describes the combined toxicological effects of two pollutants on marine animals. The model is based on a set of ordinary differential equations and from these, we derive a curve, similar to TSE, which describes all exposure combinations that result in a critical toxicological event. We use simulated data to calibrate the model and illustrate how predictions of toxicity can be made on a population level. Discussion/Conclusions: Since all possible combinations of pollutants cannot be tested experimentally the modified version of the TSE-curve can be useful to explore how different combinations affect marine life populations. Thus, it could be used to rank which pollutants are most important to reduce in the oceans. The NLME framework provides a powerful method for analyzing time-series data and could increase the statistical power when analyzing data from animal studies. In addition, it allows for simulation-based analysis, which could help reduce the number of animal experiments.
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| 15. |
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| 16. |
- Bondesson, Johan, 1991, et al.
(författare)
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Automated Quantification of Diseased Thoracic Aortic Longitudinal Centerline and Surface Curvatures
- 2020
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Ingår i: Journal of Biomechanical Engineering-Transactions of the Asme. - : ASME International. - 0148-0731 .- 1528-8951. ; 142:4
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Tidskriftsartikel (refereegranskat)abstract
- Precise description of vascular morphometry is crucial to support medical device manufacturers and clinicians for improving device development and interventional outcomes. A compact and intuitive method is presented to automatically characterize the surface geometry of tubular anatomic structures and quantify surface curvatures starting from generic stereolithographic (STL) surfaces. The method was validated with software phantoms and used to quantify the longitudinal surface curvatures of 37 human thoracic aortas with aneurysm or dissection. The quantification of surface curvatures showed good agreement with analytic solutions from the software phantoms, and demonstrated better agreement as compared to estimation methods using only centerline geometry and cross-sectional radii. For the human thoracic aortas, longitudinal inner surface curvature was significantly higher than centerline curvature (0.33 +/- 0.06 versus 0.16 +/- 0.02cm(-1) for mean; 1.38 +/- 0.48 versus 0.45 +/- 0.11cm(-1) for peak; both p<0.001). These findings show the importance of quantifying surface curvatures in order to better describe the geometry and biomechanical behavior of the thoracic aorta, which can assist in treatment planning and supplying device manufactures with more precise boundary conditions for mechanical evaluation.
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| 17. |
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| 18. |
- Bondesson, Johan, 1991, et al.
(författare)
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Definition of Tubular Anatomic Structures from Arbitrary Stereo Lithographic Surface
- 2017
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Ingår i: Initiative Seminar Engineering Health, 8-9 November 2017, Chalmers.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- An accurate description of anatomies and dynamics of vessels is crucial to understand their characteristics and improve surgical techniques, thus it is the basis, in addition to surgeon experience, on which stent design and operation procedures rely. The process of producing this description is user intensive, and recent improvement in image processing of medical3D imaging allows for a more automated workflow. However, there is a need to bridge the gap from a processed geometry to a robust mathematical computational grid. By sequentially segmenting a tubular anatomic structure, here defined by a stereo lithographic (STL) surface, an initial centerline is formed by connecting centroids of orthogonal cross-sectional contours along the length of the structure. Relying on the initial centerline, a set of non-overlapping 2D cross sectional contours are defined along the centerline, a centerline which is updated after the 2D contours are produced. After a second iteration of producing 2D contours and updating the centerline, a full description of the structure is created. Our method for describing vessel geometry shows good coherence to existing method. The main advantages of our method include the possibility of having arbitrary triangulated STL surface input, automated centerline definition, safety against intersecting cross-sectional contours and automatic clean-up of local kinks and wrinkles.
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| 19. |
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| 20. |
- Bondesson, Johan, 1991, et al.
(författare)
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Quantification of True Lumen Helical Morphology and Chirality in Type B Aortic Dissections
- 2021
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Ingår i: American Journal of Physiology - Heart and Circulatory Physiology. - : American Physiological Society. - 1522-1539 .- 0363-6135. ; 320:2, s. H901-H911
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Tidskriftsartikel (refereegranskat)abstract
- Chirality is a fundamental property in many biologic systems. Motivated by previous observations of helical aortic blood flow, aortic tissue fibers, and propagation of aortic dissections, we introduce methods to characterize helical morphology of aortic dissections. After validation on computer generated phantoms, the methods were applied to patients with type B dissection. For this cohort, there was a distinct bimodal distribution of helical propagation of the dissection with either achiral or exclusively right-handed chirality, with no intermediate cases or left-handed cases. This clear grouping indicates that dissection propagation favors these two modes, potentially due to the right-handedness of helical aortic blood flow and cell orientation. The characterization of dissection chirality and quantification of helical morphology advances our understanding of dissection pathology and lays a foundation for applications in clinical research and treatment practice. For example, the chirality and magnitude of helical metrics of dissections may indicate risk of dissection progression, help define treatment and surveillance strategies, and enable development of novel devices that account for various helical morphologies.
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| 21. |
- Bondesson, J., et al.
(författare)
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Quantification of true lumen helical morphology and chirality in type B aortic dissections
- 2021
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Ingår i: American Journal of Physiology-Heart and Circulatory Physiology. - : American Physiological Society. - 0363-6135 .- 1522-1539. ; 320:2
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Tidskriftsartikel (refereegranskat)abstract
- Chirality is a fundamental property in many biological systems. Motivated by previous observations of helical aortic blood flow, aortic tissue fibers, and propagation of aortic dissections, we introduce methods to characterize helical morphology of aortic dissections. After validation on computer-generated phantoms, the methods were applied to patients with type B dissection. For this cohort, there was a distinct bimodal distribution of helical propagation of the dissection with either achiral or exclusively right-handed chirality, with no intermediate cases or left-handed cases. This clear grouping indicates that dissection propagation favors these two modes, which is potentially due to the right-handedness of helical aortic blood flow and cell orientation. The characterization of dissection chirality and quantification of helical morphology advances our understanding of dissection pathology and lays a foundation for applications in clinical research and treatment practice. For example, the chirality and magnitude of helical metrics of dissections may indicate risk of dissection progression, help define treatment and surveillance strategies, and enable development of novel devices that account for various helical morphologies. NEW & NOTEWORTHY A novel definition of helical propagation of type B aortic dissections reveals a distinct bimodality, with the true lumen being either achiral (nonhelical) or exclusively right-handed. This right-handed chirality is consistent with anatomic and physiological phenomena such as right-handed twist during left ventricle contraction, helical blood flow, and tissue fiber direction. The helical character of aortic dissections may be useful for pathology research, diagnostics, treatment selection, therapeutic durability prediction, and aortic device design.
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| 22. |
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| 23. |
- Cardilin, Tim, 1989, et al.
(författare)
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Optimization of additive chemotherapy combinations for an in vitro cell cycle model with constant drug exposures
- 2021
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Ingår i: Mathematical Biosciences. - : Elsevier BV. - 0025-5564 .- 1879-3134. ; 338
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Tidskriftsartikel (refereegranskat)abstract
- Proliferation of an in vitro population of cancer cells is described by a linear cell cycle model with n states, subject to provocation with m chemotherapeutic compounds. Minimization of a linear combination of constant drug exposures is considered, with stability of the system used as a constraint to ensure a stable or shrinking cell population. The main result concerns the identification of redundant compounds, and an explicit solution formula for the case where all exposures are nonzero. The orthogonal case, where each drug acts on a single and different stage of the cell cycle, leads to a version of the classic inequality between the arithmetic and geometric means. Moreover, it is shown how the general case can be solved by converting it to the orthogonal case using a linear invertible transformation. The results are illustrated with two examples corresponding to combination treatment with two and three compounds, respectively.
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| 24. |
- Celander, Malin C., 1962, et al.
(författare)
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DEVELOPMENT OF ALTERNATIVE MATHEMATICAL TOOLS TO ASSESS SYNERGISTIC MIXTURE EFFECTS
- 2015
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Ingår i: 18th International symposium on Pollutant Responses in Marine Organisms (PRIMO18).
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Mixture effects are well known problems but chemical legislations are typically based on single chemical toxicity, which is unfortunate as chemicals occur as mixtures in the environment. There are mathematical models to assess additive mixture effects that are based on linear mixture effects such as toxicodynamic interactions. Chemicals with same or different mode-of-actions can also interfere with each other’s elimination pathways that can result in toxicokinetic interactions and cause indirect mixture effects. Therefore, chemicals that inhibit CYP enzymes in the elimination pathways of different classes of environmental pollutants can cause non-linear mixture effects that are more-than-additive. More-than-additive mixture effects have been observed between azoles and other classes of environmental pollutants such as estrogenic chemicals and aromatic hydrocarbons, as a result of toxicokinetic interactions via CYP1A/CYP3A inhibitions. There is need for new mathematical models to assess non-linear mixture effects. We have initiated the development of alternative mathematical tools to forecast non-linear mixture effects that are based on toxicokinetic interactions from earlier lab-studies in fish and fish cells. Time-dynamic is a key factor in toxicokinetic interactions and therefore we will combine multiple differential equations in the models. These equations describe how one chemical’s concentration changes over time in relationship to changes of another chemical’s concentration over time and how that affect biomarker responses such as CYP1A and vitellogenin. We will use statistical tools to quantitatively fit the suggested models with data from lab-studies. Non-linear models can be used to describe synergistic mixture effects. Those could be bottom-up-models, where we start from the different chemicals involved, or they could be top-down-models, where we fit a multi-dimension function to a given dataset using an auxiliary non-linear model. Our preliminary non-linear mathematical top-down model describes how the vitellogenin and the CYP1A biomarker responses can vary with concentrations of a synthetic estrogen and an antimycotic azole.
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| 25. |
- Damm, Josefin, et al.
(författare)
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An Innovative Compression System Providing Low, Sustained Resting Pressure and High, Efficient Working Pressure
- 2017
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Ingår i: Veins and Lymphatics. - : PAGEPress Publications. - 2279-7483. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- Chronic venous insufficiency (CVI) can cause considerable morbidity and reduced quality of life. Compression therapy, such as bandages and stockings, is the cornerstone and golden standard in the prevention and treatment of CVI today. It is also shown that compression used after the healing of ulcers, reduces the rate of recurrence. It has been found that compression products with a stiff, non-elastic material, are essential for an improved haemodynamic effect, indicating that low resting pressure and high working pressure is vital, in order to achieve the most effective and well tolerated compression treatment. However, one great challenge is that by applying a stiff bandage, either as a single component or as a part in a multi-component product, one always adds, a not so easily quantified, resting pressure. In order to achieve the most effective treatment it is easy to apply the bandage in a too tight and uneven manner, often resulting in painful resting pressures. In earlier studies, it has been shown that common for todays practice is that the compression treatment is dependent on the applier and that only about 10% of the healthcare personnel managers to apply a pre-defined target bandage pressure. It has also been shown that the applied pressures decrease in effectiveness, only after a couple of hours, due to e.g. oedema reduction, resulting in poor compression treatment over time.
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