19 research outputs found
Multigoal-oriented optimal control problems with nonlinear PDE constraints
In this work, we consider an optimal control problem subject to a nonlinear
PDE constraint and apply it to the regularized -Laplace equation. To this
end, a reduced unconstrained optimization problem in terms of the control
variable is formulated. Based on the reduced approach, we then derive an a
posteriori error representation and mesh adaptivity for multiple quantities of
interest. All quantities are combined to one, and then the dual-weighted
residual (DWR) method is applied to this combined functional. Furthermore, the
estimator allows for balancing the discretization error and the nonlinear
iteration error. These developments allow us to formulate an adaptive solution
strategy, which is finally substantiated via several numerical examples
Comparative chromosome painting discloses homologous Segments in distantly related mammals
Comparative chromosome painting, termed ZOO-FISH, using DNA libraries from flow
sorted human chromosomes 1,16,17 and X, and mouse chromosome 11 discloses the
presence of syntenic groups in distantly related mammalian Orders ranging from
primates (Homo sapiens), rodents (Mus musculus), even-toed ungulates (Muntiacus
muntjak vaginalis and Muntiacus reevesi) and whales (Balaenoptera physalus). These
mammalian Orders have evolved separately for 55-80 million years (Myr). We conclude
that ZOO-FISH can be used to generate comparative chromosome maps of a large
number of mammalian species
Digital chest radiography: an update on modern technology, dose containment and control of image quality
The introduction of digital radiography not only has revolutionized communication between radiologists and clinicians, but also has improved image quality and allowed for further reduction of patient exposure. However, digital radiography also poses risks, such as unnoticed increases in patient dose and suboptimum image processing that may lead to suppression of diagnostic information. Advanced processing techniques, such as temporal subtraction, dual-energy subtraction and computer-aided detection (CAD) will play an increasing role in the future and are all targeted to decrease the influence of distracting anatomic background structures and to ease the detection of focal and subtle lesions. This review summarizes the most recent technical developments with regard to new detector techniques, options for dose reduction and optimized image processing. It explains the meaning of the exposure indicator or the dose reference level as tools for the radiologist to control the dose. It also provides an overview over the multitude of studies conducted in recent years to evaluate the options of these new developments to realize the principle of ALARA. The focus of the review is hereby on adult applications, the relationship between dose and image quality and the differences between the various detector systems