Quasisymmetric parametrizations of two-dimensional metric spheres

We study metric spaces homeomorphic to the 2-sphere, and find conditions under which they are quasisymmetrically homeomorphic to the standard 2-sphere. As an application of our main theorem we show that an Ahlfors 2-regular, linearly locally contractible metric 2-sphere is quasisymmetrically homeomorphic to the standard 2-sphere, answering a question of Heinonen and Semmes

Design and evaluation of synthetic silica-based monolithic materials in shrinkable tube for efficient protein extraction

Sample pretreatment is a required step in proteomics in order to remove interferences and preconcentrate the samples. Much research in recent years has focused on porous monolithic materials since they are highly permeable to liquid flow and show high mass transport compared with more common packed beds. These features are due to the micro-structure within the monolithic silica column which contains both macropores that reduce the back pressure, and mesopores that give good interaction with analytes. The aim of this work was to fabricate a continuous porous silica monolithic rod inside a heat shrinkable tube and to compare this with the same material whose surface has been modified with a C(18) phase, in order to use them for preconcentration/extraction of proteins. The performance of the silica-based monolithic rod was evaluated using eight proteins; insulin, cytochrome C, lysozyme, myoglobin, β-lactoglobulin, ovalbumin, hemoglobin, and bovine serum albumin at a concentration of 60 μM. The results show that recovery of the proteins was achieved by both columns with variable yields; however, the C(18) modified silica monolith gave higher recoveries (92.7 to 109.7%) than the non-modified silica monolith (25.5 to 97.9%). Both silica monoliths can be used with very low back pressure indicating a promising approach for future fabrication of the silica monolith inside a microfluidic device for the extraction of proteins from biological media

Exploring Mars Mysteries in NASA Photographs: Could Some Images be Animal Skeletons?

The NASA photographs containing what appear to be animal skeletons have created a mystery that remains unsolved today. Because they generate questions and inquiries in many arenas, the animal skeleton pictures were used to help gifted students critically think about how these structures were created. Several additional exceptionalities common in most groups of students, including attention deficit disorder with and without hyperactivity and difficulties in executive functioning, were addressed through the lesson design. The exceptionalities were addressed through methods that could be used in any classroom while using the Mars Animal Skeletons to motivate and engage students. Incorporation of teaching strategies to accommodate these exceptionalities allows delivery of an engaging lesson that meets the needs of all learners

CAD learning in mechanical engineering at universities

In this study, we attempt to compile all the CAD-related concepts, contents and working methods that students of mechanical engineering should learn at universities. To do so, we first study the background to CAD-related methodologies. In second place, we compile the results of surveys administered over the past three years to our students of CAD studying mechanical engineering at our university. In third place, different publications in the literature relating to the need for CAD in industry are studied to understand the sort of CAD training that is needed in industry. In fourth place, an exploratory analysis is performed of the CAD-related contents taught at the 50 universities that top the QS (Quacquarelli Symonds) ranking. In fifth place, a survey of possible CAD-related contents is administered to teachers, instructors, and experts in CAD from those 50 leading universities in the QS ranking. The basic pillars of modeling in 3D are: methodologies of modeling, solid modeling, assemblies, and the design of technical drawings. The use of 3D printers in CAD learning means that thinking, designing, and manufacturing any object is easy at university. Knowledge of top-down/bottom-up/in-context methodologies has to be widened both for industry and for students. Design intent must be introduced in CAD from the very beginning so that all the models are flexible and robust. The students expressed a preference to learn the concepts through a set of good practice exercises and to be evaluated by completing a final course assignment of their choice

Toward optimised skeletons for heterogeneous parallel architecture with performance cost model

High performance architectures are increasingly heterogeneous with shared and distributed memory components, and accelerators like GPUs. Programming such architectures is complicated and performance portability is a major issue as the architectures evolve. This thesis explores the potential for algorithmic skeletons integrating a dynamically parametrised static cost model, to deliver portable performance for mostly regular data parallel programs on heterogeneous archi- tectures. The rst contribution of this thesis is to address the challenges of program- ming heterogeneous architectures by providing two skeleton-based programming libraries: i.e. HWSkel for heterogeneous multicore clusters and GPU-HWSkel that enables GPUs to be exploited as general purpose multi-processor devices. Both libraries provide heterogeneous data parallel algorithmic skeletons including hMap, hMapAll, hReduce, hMapReduce, and hMapReduceAll. The second contribution is the development of cost models for workload dis- tribution. First, we construct an architectural cost model (CM1) to optimise overall processing time for HWSkel heterogeneous skeletons on a heterogeneous system composed of networks of arbitrary numbers of nodes, each with an ar- bitrary number of cores sharing arbitrary amounts of memory. The cost model characterises the components of the architecture by the number of cores, clock speed, and crucially the size of the L2 cache. Second, we extend the HWSkel cost model (CM1) to account for GPU performance. The extended cost model (CM2) is used in the GPU-HWSkel library to automatically nd a good distribution for both a single heterogeneous multicore/GPU node, and clusters of heteroge- neous multicore/GPU nodes. Experiments are carried out on three heterogeneous multicore clusters, four heterogeneous multicore/GPU clusters, and three single heterogeneous multicore/GPU nodes. The results of experimental evaluations for four data parallel benchmarks, i.e. sumEuler, Image matching, Fibonacci, and Matrix Multiplication, show that our combined heterogeneous skeletons and cost models can make good use of resources in heterogeneous systems. Moreover using cores together with a GPU in the same host can deliver good performance either on a single node or on multiple node architectures