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The differential operator -(d2/dx2)-(y/x), γ∈R, in one dimension is studied using distribution theory. It is proven that there exists a unique self-adjoint operator corresponding to the differential expression understood in the principle-value sense. Point interactions determined by the singular operator -(d2/dx2)-(y/x)+αδ(x) are studied
Results from the application of a modified dual photopeak window scatter correction method to Monte Carlo simulated Tl-201 emission images are presented. In the Monte Carlo investigation, individual simulations are performed for six radiation emissions of Tl-201. For each emission, point sources of Tl-201 are imaged at various locations in a water-filled elliptical tub phantom using three energy w
Data supporting the notion that exercise during growth built a stronger skeleton is compelling. Exercise during growth, especially during the pre-pubertal years, increases bone mineral density (BMD) and perhaps also bone size, each independently conferring bone strength. In adulthood, exercise at best halts bone loss or increases BMD by a few percentage points, an increase of questionable biologic
This thesis deals with computational methods in algebra, mainly focusing on the concept of Gröbner and SAGBI bases in non-commutative algebras. The material has a natural division into two parts. The first part is a rather extensive treatment of the basic theory of Gröbner bases and SAGBI bases in the non-commutative polynomial ring. The second part is a collection of six papers. In the first pap
The nigrostriatal dopamine (DA) system has an essential role in the selection and control of movement sequences, and its degeneration causes the characteristic motor symptoms of Parkinson's disease. Parkinsonian motor symptoms are alleviated by l-DOPA, but this treatment induces motor fluctuations and dyskinesias (abnormal involuntary movements). Clinical and experimental findings indicate that th
Scattering of electromagnetic waves from a red blood cell is simulated using the finite-difference time-domain method (FDTD), the Rytov approximation and the discrete dipole approximation (DDA). Both FDTD and DDA are full wave methods that give accurate results in a wide range of wavelengths. The Rytov approximation is a much simpler method that is limited to scattering angles within 30/spl deg/ f
Lifetimes for the3S1,3P0, 1, 2 and3D1, 2, 3 states in the 3s23p5p configuration of silicon have been determined using stepwise dye laser excitation and time resolved detection. A comparison is made with theoretical values, calculated using multi-configuration Hartree-Fock wavefunctions. Laser-evaporation was used to produce free silicon atoms by focusing a Nd: YAG laser on a rotating silicon targe
The performance of a turbo code is dependent on two code properties: its distance spectrum and its suitability to be iteratively decoded. Both these properties are influenced by the choice of interleaver used in the turbo encoder. This paper presents an interleaver design criterion that focuses on the performance of iterative decoding, based on the correlation properties of the extrinsic inputs. I
A contaminated site at Lernacken in southern Sweden, formerly used for sludge disposal, was investigated using a 3-D resistivity imaging technique. The data acquisition was carried out using a roll-along technique for 3-D data acquisition that allows using standard multielectrode equipment designed for engineering and environmental applications. The technique allows for the measurement of large tr
AIMS: The increase in risk for cardiovascular complications in diabetic women is even greater than that in diabetic men. We found arterial stiffness to be increased in women, but not in men, with Type 1 diabetes mellitus (DM). The aims of the present study were to evaluate whether the changes in arterial distensibility are influenced by diabetes duration and to evaluate any association between aut
The aim of this study was to compare interstitial laser thermotherapy with excision of a liver tumour. A dimethylhydrazine-induced adenocarcinoma was implanted into the left lateral lobe of the rat liver, and treatment was performed 8 days later. Rats were treated with resection of the tumour-bearing lobe or underwent interstitial laser thermotherapy, which was performed at a steady-state temperat
This paper argues that there is reason to be skeptical about the idea that the transition to a service economy will bring about dematerialization of production and consequent environmental improvement. This is because the shift to a service economy is an illusion in terms of real production, but is instead generated by the fall in the price of manufacturing goods relative to services, which is in
We consider a two-echelon distribution inventory system with a central warehouse and a number of retailers. The retailers face stochastic demand. The system is controlled by continuous review installation stock (R,Q) policies with given batch quantities. One way to decentralize the system control is to provide a backorder cost to the warehouse, and let the warehouse choose its reorder point so tha
In the generalization of the cranking model from rotation about a principal axis [one dimensional (1D)] to tilted rotation (2D and 3D), the mapping of the lowest total routhian on the yrast band is broken. In tilted rotation the single-particle energy diagrams cannot alone be used to construct the yrast band, because they lack information of the spin component perpendicular to the rotation axis. I
