The Riccati equation plays as important a role in scattering theory as it does in linear least squares estimation theory. However, in the scattering literature, a somewhat different framework of treating the Riccati equation has been developed. This framework is shown to be appropriate for estimation problems and makes possible simple derivations of known results as well as leading to several new

A certain "star-product" formalism in scattering theory as developed by Redheffer is shown to also be naturally applicable to discrete-time linear least-squares estimation problems. The formalism seems to provide a nice way of handling some of the well-known algebraic complications of the discrete-time case, e.g., the distinctions between time and measurement updates, predicted and filtered estima

The results stated in the above paper1 concerning an approved stochastic approximation method are considered. Formulas for the variances of the estimates are derived, and it is found that, in fact, the new algorithm is inferior to previously suggested ones.

At the same time as our dependence on IT systems increases, the number of reports of problems caused by failures of critical IT systems has also increased. Today, almost every societal system or service, e.g., water supply, power supply, transportation, depends on IT systems, and failures of these systems have serious and negative effects on society. In general, public organizations are responsibl

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OBJECTIVES: The predictive ability of the STarT Back Tool (SBT) has not yet been examined among acute/subacute back and/or neck pain in a primary care setting in respect to health-related quality of life (HRQoL) and work ability outcomes. The aim of this study was to evaluate the SBT's predictive validity for HRQoL and work ability outcomes at long-term follow-up in a population with acute/subacut

Background: Implementation of clinical health promotion (CHP) aiming at better health gain is slow despite its effect. CHP focuses on potentially modifiable lifestyle risks such as smoking, alcohol, diet, and physical inactivity. An operational program was created to improve implementation. It included patients, staff, and the organization, and it combined existing standards, indicators, documenta

Monoamines are presumed to be diffuse metabotropic neuromodulators of the topographically and temporally precise ionotropic circuitry which dominates CNS functions. Their malfunction is strongly implicated in motor and cognitive disorders, but their function in behavioral and cognitive processing is scarcely understood. In this paper, the principles of such a monoaminergic function are conceptuali

Ichthyosaurs are extinct marine reptiles that display a notable external similarity to modern toothed whales. Here we show that this resemblance is more than skin deep. We apply a multidisciplinary experimental approach to characterize the cellular and molecular composition of integumental tissues in an exceptionally preserved specimen of the Early Jurassic ichthyosaur Stenopterygius. Our analyses

High-brilliance x-ray sources (x-ray free-electron lasers or diffraction-limited storage rings) allow the visualization of ultrafast processes in a 2D manner using single exposures. Current 3D approaches scan the sample using multiple exposures, and hence they are not compatible with single-shot acquisitions. Here we propose and verify experimentally an x-ray multi-projection imaging approach, whi

Heart transplantation is the only cure for patients with terminal cardiac failure, but the supply of allogeneic donor organs falls far short of the clinical need1–3. Xenotransplantation of genetically modified pig hearts has been discussed as a potential alternative4. Genetically multi-modified pig hearts that lack galactose-α1,3-galactose epitopes (α1,3-galactosyltransferase knockout) and express

The literature describing medical aspects on sauna bathing is briefly reviewed. The circulatory effects of heating and subsequent cooling related to sauna bath differ with age, underlying medical condition and use of drugs. The circulatory changes may often be beneficial but can sometimes prove dangerous. More than 2000 sauna bathers were followed for around 20 years in a Finnish population study.

Microglia represent a specialized population of macrophages-like cells in the central nervous system (CNS) considered immune sentinels that are capable of orchestrating a potent inflammatory response. Microglia are also involved in synaptic organization, trophic neuronal support during development, phagocytosis of apoptotic cells in the developing brain, myelin turnover, control of neuronal excita