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Teema : hepatologia. English summaryPeer reviewe

Performance of imaging studies in patients with suspected appendicitis after stratification with adult appendicitis score

Background: Diagnostic scoring is used to stratify patients with suspected appendicitis into three groups: high, intermediate, and low probability of appendicitis. The stratification can be used for selective imaging to avoid the harms of radiation without compromising diagnostic accuracy. The aim was to study how stratification by Adult Appendicitis Score affects diagnostic performance of imaging studies. Methods: Analysis of 822 patients who underwent diagnostic imaging for suspected appendicitis was made. Adult Appendicitis Score was used to stratify patients into groups of high, intermediate, and low probability of appendicitis. Diagnostic performance of computed tomography (CT) and ultrasound (US) was compared between these patient groups. Results: After scoring, pre-test probability of appendicitis ranged from 9-16% in low probability group to 75-79% in high probability group in patients who underwent US or CT. Post-test probability of appendicitis after positive CT was 99, 91, and 75% in high probability, intermediate probability and low probability groups, respectively, p <0.001. After positive US the respective probabilities were 95, 91 and 42%, p <0.001. Conclusion: Diagnostic imaging has limited value in patients with low probability of appendicitis according to Adult Appendicitis Score.Peer reviewe

Monte Carlo Analysis of Circulating Currents in Random-Wound Electrical Machines

Electrical machines with stranded random windings often suffer from considerable circulating current losses. These losses have been poorly studied because of the difficulty and computational cost of modelling stranded windings, and the stochastic nature of the problem due to the uncertain positions of the strands. This paper proposes two methods to model random stranded windings of arbitrary complexity. Firstly, a circuit model considering the entire main flux path is presented, and some practical implementation considerations are discussed. Secondly, a computationally efficient finite element approach based on non-conforming meshing is presented. Finally, a method is proposed to model the random packing process of strands within a slot, without any re-meshing or inductance re-calculation required. The proposed methods are then compared to special no-rotor measurement data of a large number of high-speed induction machines, and a good agreement is observed.Peer reviewe

Nutrient recycling – from vision to practice

Nutrient losses to water need to be reduced. This can be accomplished by sustainable use of nutrients and by recycling the nutrients contained in organic side streams. Researchers propose specific actions to speed up the changes needed for better nutrient recycling in Finland.201

Towards a breakthrough in nutrient recycling : State-of-the-art and recommendations for developing policy instruments in Finland

The report has been complemented on 11.9.2018This report describes the state-of-the-art in phosphorus and nitrogen recycling in Finland and looks at basic data on the volumes and geographical distribution of biomasses and their nutrients. Based on this data, the report makes proposals for measures aiming to promote nutrient recycling. This report was prepared collaboratively by experts at the institutions making up the Finnish Partnership for Research on Natural Resources and the Environment (LYNET) to underpin a national action plan on nutrient recycling. Of all sectors in Finland, agriculture is the largest user and recycler of phosphorus and nitrogen. Different biomasses contain an annual total of approximately 26,000 t of recyclable phosphorus, which exceeds the fertilisation needs of grasslands and cereal crops in the entire area of Finland. The volume of nitrogen contained in biomasses is approximately 95,000 t. Still, approx. 11,000 t of phosphorus and 152,000 t of nitrogen are annually used in Finland as conventional inorganic fertilisers. There is a regional imbalance between manure production and crop nutrient requirements. The breakthrough in nutrient recycling means increased implementation of manure processing, thus making manure nutrients easier to transport and reducing the use of conventional inorganic fertilisers. At minimum 20% of the entire volume of manure generated in Finland will require advanced processing to enable long-distance transport of the manure phosphorus to areas in need of it. This requires separation of water. The highest demand for advanced processing is experienced in the regions of Ostrobothnia (approx. 60% at minimum), South Ostrobothnia and Satakunta (approx. 30 %) and Southwest Finland (13%). In the agricultural sector, fertilisation is currently guided by a wide array of different policy instruments, which make up an incoherent and unstructured whole. The instruments cause considerable amounts of regulatory burden, but appear to do little to promote sustainable nutrient recycling. This report proposes a total reform of the policy instruments to boost the recycling of nutrients. All legal standards related to fertilisation should be merged into a single statute, for example by developing the Nitrate Decree. At the same time, the current policy that controls nutrient use via the EU agri-environmental scheme should be abandoned, and the role of the environmental permit for livestock installations and its relationship with general regulatory instruments be clarified. A field plot specific nutrient database should be created to support guidance. The knowledge base of nutrient recycling should be developed by creating and maintaining a comprehensive data system on the quantities, properties and locations of nutrient-rich biomasses and ashes and their current processing methods. The report also proposes setting regional processing targets for livestock manure. Key objectives should include reducing excessive fertilisation in crop production. The goal of normative guidance should be nutrient use according to the crop needs.201

Analytic theory of ground-state properties of a three-dimensional electron gas at varying spin polarization

We present an analytic theory of the spin-resolved pair distribution functions $g_{\sigma\sigma'}(r)$ and the ground-state energy of an electron gas with an arbitrary degree of spin polarization. We first use the Hohenberg-Kohn variational principle and the von Weizs\"{a}cker-Herring ideal kinetic energy functional to derive a zero-energy scattering Schr\"{o}dinger equation for $\sqrt{g_{\sigma\sigma'}(r)}$. The solution of this equation is implemented within a Fermi-hypernetted-chain approximation which embodies the Hartree-Fock limit and is shown to satisfy an important set of sum rules. We present numerical results for the ground-state energy at selected values of the spin polarization and for $g_{\sigma\sigma'}(r)$ in both a paramagnetic and a fully spin-polarized electron gas, in comparison with the available data from Quantum Monte Carlo studies over a wide range of electron density.Comment: 13 pages, 8 figures, submitted to Phys. Rev.

Biliary Anomalies in Patients With HNF1B Diabetes

Context: The clinical spectrum of organogenetic anomalies associated with HNF1B mutations is heterogeneous. Besides cystic kidney disease, diabetes, and various other manifestations, odd cases of mainly neonatal and posttransplantation cholestasis have been described. The biliary phenotype is incompletely defined. Objective: To systematically characterize HNF1B-related anomalies in the bile ducts by imaging with magnetic resonance imaging (MRI) or magnetic resonance cholangiopancreatography (MRCP). Setting and Patients: Fourteen patients with HNF1B mutations in the catchment area of the Helsinki University Hospital were evaluated with upper abdominal MRI and MRCP. Blood samples and clinical history provided supplemental data on the individual phenotype. Main Outcome Measure(s): Structural anomalies in the biliary system, medical history of cholestasis, other findings in abdominal organs, diabetes and antihyperglycemic treatment, hypomagnesemia, and hyperuricemia. Results: Structural anomalies of the bile ducts were found in seven of 14 patients (50%). Six patients had choledochal cysts, which are generally considered premalignant. Conclusions: Structural anomalies of the biliary system were common in HNF1B mutation carriers. The malignant potential of HNF1B-associated choledochal cysts warrants further studies.Peer reviewe

Treatment of Correlation Effects in Electron Momentum Density: Density Fuctional Theory and Beyond

Recent high resolution Compton scattering experiments clearly reveal that there are fundamental limitations to the conventional local density approximation (LDA) based description of the ground state electron momentum density (EMD) in solids. In order to go beyond the framework of the density functional theory (DFT), we consider for the correlated system a BCS-like approach in which we start with a singlet pair wavefunction or a 'geminal' from which the many body wavefunction is then constructed by taking an antisymmetrized geminal product (AGP). A relatively simple practical implementation of the AGP method is developed where the one-particle orbitals are approximated by the Kohn-Sham solutions used in standard band computations, and the orbital-dependent BCS energy scale $\Delta_i$ is determined through a readily computed exchange-type integral. The methodology is illustrated by considering EMD and Compton profiles in Li, Be and Al. It is found that in Li the present scheme predicts a substantial renormalization of the LDA result for the EMD; in Be, the computed correlation effect is anisotropic, while in Al, the deviations from the LDA are relatively small. These theoretical predictions are in qualitative accord with the corresponding experimental observations on Li, Be and Al, and indicate the potential of the AGP method for describing correlation effects on the EMD in wide classes of materials.Comment: 4 figures, accepted for publication in J. Phys. Chem. Solid