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The Influence of Phantom Size, Shape, and Density, and Collimator Selection on the Dual Photopeak Scatter Correction Method

Results from a Monte Carlo investigation are presented for the application of the dual photopeak window (DPW) scatter correction method to phantom geometries of varying shapes, sizes, and densities as well as to several collimators. A Monte Carlo program was used to simulate a Tc-99m point source at locations of 0.5 cm from the phantom surface, at the center, 0.5 cm from the bottom, and 4/5 the di

Were glacial iceberg surges in the North Atlantic triggered by climatic warming?

High-resolution physical, mineralogical, sedimentological and micropalaeontological studies were carried out on North Atlantic cores from the Reykjanes Ridge at 59degreesN and from the region southwest of the Faeroe Islands. All core sites are situated along the pathway of Iceland-Scotland Overflow Water (ISOW) and the various parameters measured display similar features. Previously identified car

A Mathematical Model for Calculating Heat Release in the Room Corner Test

A mathematical model is presented for calculating heat release rate in the Room Corner Test, where lining materials are mounted on both walls and ceiling. The model is based on a thermal theory for concurrent flow flame spread. By using a simple mathematical representation of the heat release rate from the Cone Calorimeter, analytical solutions are arrived at for the velocity and position of the p

Protection of Accrued Pension Rights - An Inquiry into Reforms of Statutory and Occupational Pension Schemes in a German, Norwegian and Swedish Context

How is the conflict between a protection of accrued pension rights and economic, political and social interests in reforming the pension scheme resolved in different countries and regarding different kinds of pension schemes? What legal or political mechanisms exist to protect accrued pension rights and to resolve this conflict? This thesis takes a comprehensive view on the pension situation of t

Stress computations on perforated polygonal domains

A high order accurate and fast algorithm is constructed for 2D stress problems on multiply connected finite domains. The algorithm is based on a Fredholm integral equation of the second kind with non-singular operators. The unknown quantity is the limit of an analytic function. On polygonal domains there is a trade-off between stability and rate of convergence. A moderate amount of precomputation

Algebraic lower bounds for the uniform radius of spatial analyticity for the generalized KdV equation

The generalized Korteweg-de Vries equation has the property that solutions with initial data that are analytic in a strip in the complex plane continue to be analytic in a strip as time progresses. Established here are algebraic lower bounds on the possible rate of decrease in time of the uniform radius of spatial analyticity for these equations. Previously known results featured exponentially dec

Aluminum complexation suppresses citrate uptake by acid forest soil microorganisms

Organo-mineral interactions have been hypothesized to play a major role in biogeochemical cycling and pedogenesis in some forest soils. These processes are likely to be controlled to some extent by their persistence in soil, however, the factors regulating their bioavailability remain poorly understood. Therefore, we investigated the microbial utilization of C-14-labeled citrate in glass bead fill

Tissue plasminogen activator and plasminogen activator inhibitor-1 in stroke patients

BACKGROUND AND PURPOSE: Abnormal endogenous fibrinolytic activity may be a risk factor for stroke. Since the possible variation of tissue-type plasminogen activator (TPA) antigen and plasminogen activator inhibitor-1 (PAI-1) antigen concentrations over time after stroke has been rarely studied, it was examined in plasma from stroke patients in the acute and convalescent phases of the disease and i

Electric brain responses obtained from newborn infants to changes in duration in complex harmonic tones

Event-related brain potentials of 10 full-term newborns in response to duration changes in complex, harmonic tones known to elicit prominent mismatch negativity (MMN) response in adults were investigated. Here we report that duration changes elicited prominent MMN responses in a 11 newborns tested. In contrast, MMN has been reported in as little as 50% of the infants in some previous studies using

Washout of 133-xenon as an objective assessment of paranasal sinus ventilation in endoscopic sinus surgery

Endoscopic sinus surgery (ESS) is today a common method for the treatment of chronic rhinosinusitis. Assessment of the results has been based mainly upon subjective evaluation, and only a few reports present objective measurements, In the present study, the 133-xenon washout technique was used for preoperative and postoperative evaluation of paranasal sinus ventilation in 12 patients selected for

On the Selection of Methods and Tools for Analysis of Heat and Power Plants

Popular Abstract in Swedish Affärsklimatet för dagens energimarknad har varit händelserik de senaste två decennierna med introduktaion av den avreglerade elmarknaden och den ökade vikten av miljöfrågor vid design och inköp av energirelaterade anläggningar. Detta har bidragit med krav om nya analyskriterier, vilka inte bara påverkar den tekniska utformningen av komponenter och system, utan även tilThe business climate of the energy market has been eventful over the last two decades, particularly with the introduction of the deregulated electricity market and promotion of environmental issues. This has subsequently lead to new analysis criteria, influencing both technology requirements and production costs. To be able to manage all the questions that have arisen from this the knowledge of th

Den anomiska rätten. Om undantagskonstruktionen av de rent ideella kränkningsersättningarna.

Anomi är ett centralt rättssociologiskt begrepp introducerat av Émile Durkheim (1858-1917) som beskriver ett tillstånd av oklarhet och normlöshet som överförs på individen vilket får denne att känna otillfredsställelse. Identifieringen av anomi indikerar rättsliga förändringsprocesser och tydliggör samtidens rättskultur när mönster bryts. Kränkningsersättning, s.k. rent ideellt skadestånd, som akt

Dust Measurements During Galileo's Approach to Jupiter and Io Encounter

About a hundred dust impacts per day were detected during the first week in December 1995 by Galileo during its approach to Jupiter. These impacts were caused by submicrometer-sized particles that were just above the detection limit. After the closest approach to Io on 7 December, impacts of these small particles ceased. This effect is expected for dust grains emitted from Io that exit the field o

Asymptomatic leg atherosclerosis is reduced by regular physical activity. Longitudinal results from the cohort "men born in 1914"

OBJECTIVE: To study whether physical activity is associated with reduced occurrence of asymptomatic leg atherosclerosis. DESIGN: Longitudinal and cross-sectional analyses of the population-based cohort "men born in 1914". METHODS: Comparison of the systolic ankle/arm pressure index (AAI) at age 68 in groups who were sedentary, performed some activity, and performed regular physical training at 55