On boundary layers

https://projecteuclid.org/download/pdf_1/euclid.afm/148589849

A Quantification of the Morphological Computations in Perception Systems

We suggest a straightforward strategy how to quantify how much "computation" a given morphology is performing while transforming a stimuli

Side reactions do not completely disrupt linear self-replicating chemical reaction systems

A crucial question within the fields of origins of life and metabolic networks is whether or not a self-replicating chemical reaction system is able to persist in the presence of side reactions. Due to the strong nonlinear effects involved in such systems, they are often difficult to study analytically. There are however certain conditions that allow for a wide range of these reaction systems to be well described by a set of linear ordinary differential equations. In this article, we elucidate these conditions and present a method to construct and solve such equations. For those linear self-replicating systems, we quantitatively find that the growth rate of the system is simply proportional to the sum of all the rate constants of the reactions that constitute the system (but is nontrivially determined by the relative values). We also give quantitative descriptions of how strongly side reactions need to be coupled with the system in order to completely disrupt the system

Optimization of additive chemotherapy combinations for an in vitro cell cycle model with constant drug exposures

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

Device and method for treating ruptured aneurysms

A stent device for treating an aneurysm is disclosed. The stent device comprises an expandable balloon with a channel extending through said balloon from one side to another, and a supporting stent connected to said balloon. In an operative disposition, when the expandable balloon is expanded, the supporting stent is arranged at least partly within said channel of said expandable balloon. Further, the supporting stent has walls which are permeable to blood. The stent device may be introduced and removed by endoscopic procedures, with a relatively simple procedure. Thus, the stent device is highly useable for fast and temporary treatment of ruptured aneurysms

A new stocking compression system with a low well-defined resting pressure and a high working pressure

Compression stockings should preferably apply the intended pressure regardless of leg shape and circumference. This may require custom fitting. Today’s sizing system is focusing on the exerted pressure at the ankle region. A ready-made stocking may therefore exert correct pressure at the ankle, but the pressure at the calf may be well exceeded due to the actual size of the calf, leading to a tourniquet effect, ischemia or even increased risk of thrombosis. Even with a perfectly-fitted stocking, the problem with changes in leg circumference due to the increase/decrease in oedema is not resolved. Stocking donning problems vary with compression class and elasticity of the material used. Added pressure over the calf area has been reported to improve venous pumping function more than graduated compression. Adding stiffness over the calf area may also improve the pumping function. H\ue4fner et.al. stated that “Hemodynamically optimal compression products will make medical compression therapy an even more useful tool in the field of phlebology”. With new smart textiles, the pressure can be controlled. The aim was therefore to evaluate a prototype of a stocking compression system with specified well-defined target resting pressure and supposedly high working pressure created by stiffness

Combining engineering and teacher education – ideas and experiences from Chalmers University of Technology

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

The 3G inequality for a uniformly John domain

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 $\in$ Dare 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

Fermat Pedagogy – a method to help students make effective lecture notes

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

The 3G inequality for a uniformly John domain

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 $\in$ Dare 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