Separability and the stella octangula

A geometrical picture of separability of 2 x 2 composite quantum systems, showing the region of separable density matrices in the space of hermitian matrices, is given. It rests on the criterion of separability given by Peres, and it is an extension of the ``Horodecki diagram'' and the ``stella octangula'' described by Aravind.Comment: 4 pages, 1 figur

Educating engineering designers for a multidisciplinary future

Contemporary companies on a global market are experiencing constantly changing business demands and increased competition. Increasing focus in product development is now put on issues like understanding users and their needs, the context where users’ activities take place and creating sustainable solutions (McAloone, et.al., 2007). In manufacturing companies, engineering designers play a significant role in realising what is captured in these words.Future engineering designers will hold wider responsibilities for such tasks (McAloone, et.al., 2007; Larsson, et.al., 2005), thus challenging current engineering design education. Educating engineering designers today significantly differs from traditional engineering education (McAloone, et.al., 2007). However, a broader view of design activities gains little attention. The project course Product/Service-Systems, which is coupled to the lecture based course Product life and Environmental issues at the Technical University of Denmark (DTU) and the master programme in Product Development at the Luleå University of Technology (LTU), Sweden, are both curriculums with a broader view than traditional (mechanical) engineering design. Based on these two representatives of a Scandinavian approach, the purpose in this presentation is to describe two ways of educating engineering designers to enable them to develop these broader competencies of socio-technical aspects of engineering design. Product Development at LTU A process, called Participatory Product Innovation (P2I) underpins the master programme Product Development and originates from the Design for Wellbeing (DfW) framework (Larsson, et.al., 2005). This is an inclusive framework which seeks to bring together business, human issues and technology in a comprehensive approach to support the creation of tomorrow’s innovations. A main principle is that many different disciplines should contribute to spur innovation by collaboration across disciplines (Larsson, et.al., 2007). The P2I process starting position is in Needfinding (Patnaik and Becker, 1999), were the students conduct observations and interviews to gain access to ualities in the users’ context. An identified challenge here is to keep people in view and not jump into conclusions, i.e., to understand a situation perceived by its actors as problematic and to widen the design space. Product/Service-Systems at DTU Besides the teaching of traditional engineering skills, the curriculum for the project course aims to build up multidisciplinary competences such as understanding the socio technical aspects of product design and synthesis of products and delivery systems. The students are assigned to redesign an existing physical product, such as a washing machine, and turn it into a product/service-system. The main objective for the project is that the resulting solution should have a substantially lower environmental impact whilst maintaining a similar functional performance as the initial product. The student teams are first guided through an analysis of the initial product’s product life cycle, yielding insights into four aspects of product design:1. indentification of current environmental impacts, 2. life phase systems the product encounters, 3. activities that involve the human actor (i.e. customer) and the product, 4. actor-network that support and supply these activities throughout the product’s life. Based on the analysis, goals are set for the improved solution and concepts are developed for a new product/service-system. This way the students are lead through engineering and socio-technical analysis tasks and thereby laying the foundation for their synthesis work in the concept development phase of the project. Concluding Remark By emphasising socio technical aspects in a process model or in a project course, the students are more likely to consider users, their context and sustainable solutions. This we see as essential competencies in product/service-system design and functional product development. References Larsson, A., Larsson, T., Leifer, L., Van der Loos, M., Feland, J. (2005), Design for Wellbeing: Innovations for People, In proceedings of 15th International Conference on Engineering Design, ICED 05, August 15-18, Melbourne, Australia.McAloone, T.C., Andreasen, M.M., Boelskifte, P. (2007), A Scandinavian Model of Innovative Product Development, In Proccedings of the 17th CIRP Design Conference, Springer-Verlag, Berlin. Patnaik, D., Becker, R. (1999), Needfinding: The Why and How of Uncovering People’s Needs, Design Management Journal, 10 (2), 37-43.Godkänd; 2007; 20071201 (tobias)Fastelaboratoriet - VINNEX

Birkhoff's polytope and unistochastic matrices, N=3 and N=4

The set of bistochastic or doubly stochastic N by N matrices form a convex set called Birkhoff's polytope, that we describe in some detail. Our problem is to characterize the set of unistochastic matrices as a subset of Birkhoff's polytope. For N=3 we present fairly complete results. For N=4 partial results are obtained. An interesting difference between the two cases is that there is a ball of unistochastic matrices around the van der Waerden matrix for N=3, while this is not the case for N=4.Comment: 30 pages, 4 figure

Effects of the gg-factor in semi-classical kinetic plasma theory

A kinetic theory for spin plasmas is put forward, generalizing those of previous authors. In the model, the ordinary phase space is extended to include the spin degrees of freedom. Together with Maxwell's equations, the system is shown to be energy conserving. Analysing the linear properties, it is found that new types of wave-particle resonances are possible, that depend directly on the anomalous magnetic moment of the electron. As a result new wave modes, not present in the absence of spin, appear. The implications of our results are discussed.Comment: 4 pages, two figures, version to appear in Physical Review Letter

Improvement of arterial oxygenation in free-ranging moose (Alces alces) immobilized with etorphine-acepromazine-xylazine

Background: The effect of intranasal oxygen and/or early reversal of xylazine with atipamezole on arterial oxygenation in free-ranging moose (Alces alces) immobilized with etorphine-acepromazine-xylazine with a cross-sectional clinical study on 33 adult moose was evaluated. Moose were darted from a helicopter with 3.37 mg etorphine, 15 mg acepromazine and 75 mg xylazine. Intranasal oxygen at a flow rate of 4 L/min and/or early reversal of xylazine with 7.5 mg atipamezole to improve oxygenation was evaluated, using four treatment regimens; intranasal oxygen (n = 10), atipamezole intramuscularly (n = 6), atipamezole intravenously (n = 10), or a combination of atipamezole intravenously and intranasal oxygen (n = 7). Arterial blood was collected 7–30 minutes (min) after darting, and again 15 min after institution of treatment and immediately analyzed using an i-STAT®1 Portable Clinical Analyzer. Results: Before treatment the mean ± SD (range) partial pressure of arterial oxygen (PaO2) was 62 ± 17 (26–99) mmHg. Twenty-six animals had a PaO2 < 80 mmHg. Ten had a PaO2 of 40–60 mmHg and three animals had a PaO2 < 40 mmHg. Intranasal oxygen and intravenous administration of atipamezole significantly increased the mean PaO2, as did the combination of the two. In contrast, atipamezole administered intramuscularly at the evaluated dose had no significant effect on arterial oxygenation. Conclusions: This study shows that intranasal oxygen effectively improved arterial oxygenation in immobilized moose, and that early intravenous reversal of the sedative component, in this case xylazine, in an opioid-based immobilization drug-protocol significantly improves arterial oxygenation