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The well-known and commonly accepted finite dimensional model qualitatively describing surge instabilities in centrifugal (and axial) compressors is considered. The problem of global output feedback stabilization for it is solved. The solution relies on two new criteria for global stability proposed for a class of nonlinear systems exploiting quadratic constraints for infinite sector nonlinearitie

A constitutive theory is proposed, which possesses the possibilities of modelling all the important features or the behaviour or frictional materials such as: influence of all three stress invariants, coupling between deviatoric and volumetric response, dilatancy, softening, and different behaviour in loading and unloading. The basic constitutive assumptions are relations between properly defined

Over the past few decades, the literature on agency autonomy has increased rapidly. It still struggles, however, to find solid evidence for specific factors explaining variations in autonomy. This paper argues that a reason for this is basic assumptions in this line of research, and more specifically the tendency to focus on factors on the collective level. Using the distinction between methodolog

Recent results have shown that denoising an image with the Rudin, Osher and Fatemi (ROF) total variation model can be accomplished by solving a series of binary optimization problems. We observe that this fact can be used in the other direction. The procedure is applied to the two-phase, piecewise constant Mumford-Shah functional, where an image is approximated with a function taking only two valu

Höftprotesoperationer har blivit ett säkert och mycket framgångsrikt kirurgiskt ingrepp och lever upp till mycket av de förväntningar som patienterna har. Förbättring av material, protesdesign och kirurgiska tekniker har förlängt protesöverlevnaden påtagligt. Emellertid är icke optimal protesplacering och felaktigt val av komponentstorlekar känt för att öka risken för biomekaniska problem och ökatTotal hip arthroplasty (THA) has become a safe and very successful surgical intervention. A vast majority of patients get their expectations met. Improvement of materials, implant designs, and surgical techniques, have extended prosthetic survival. However, inferior placement and sizing of a hip prosthesis are known to increase the risk of mechanical failure, wear, and early loosening as well as p

The maritime expansion of Scandinavian populations during the Viking Age (about ad 750–1050) was a far-flung transformation in world history1,2. Here we sequenced the genomes of 442 humans from archaeological sites across Europe and Greenland (to a median depth of about 1×) to understand the global influence of this expansion. We find the Viking period involved gene flow into Scandinavia from the

Hypertension affects approximately one third of the world’s adult population and is a major cause of premature death despite considerable advances in pharmacological treatments. Growing evidence supports the use of lifestyle interventions for the prevention and adjuvant treatment of hypertension. In this Review, we provide a summary of the epidemiological research supporting the preventive and ant

The dynamics of planetesimals plays an important role in planet formation because their velocity distribution sets the growth rate to larger bodies. When planetesimals form in the gaseous environment of protoplanetary discs, their orbits are nearly circular and planar due to the effect of gas drag. However, mutual close encounters of the planetesimals increase eccentricities and inclinations until

This talk discusses two analytical calculations relevant for the Standard Model calculation of the muon g−2. The first part is the recent derivation of the quark-loop as the first term in a well-defined operator-product expansion for the short-distance part of the hadronic light-by-light contribution, as well as the calculation of the next term. The second part is the calculation of finite volume