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Search Results: 1 - 10 of 828 matches for " Olofsson Camilla "
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Nuclear medicine technologists are able to accurately determine when a myocardial perfusion rest study is necessary
Tr?g?rdh Elin,Johansson Liselott,Olofsson Camilla,Valind Sven
BMC Medical Informatics and Decision Making , 2012, DOI: 10.1186/1472-6947-12-97
Abstract: Background In myocardial perfusion scintigraphy (MPS), typically a stress and a rest study is performed. If the stress study is considered normal, there is no need for a subsequent rest study. The aim of the study was to determine whether nuclear medicine technologists are able to assess the necessity of a rest study. Methods Gated MPS using a 2-day 99mTc protocol for 121 consecutive patients were studied. Visual interpretation by 3 physicians was used as gold standard for determining the need for a rest study based on the stress images. All nuclear medicine technologists performing MPS had to review 82 training cases of stress MPS images with comments regarding the need for rest studies, and thereafter a test consisting of 20 stress MPS images. After passing this test, the nuclear medicine technologists in charge of a stress MPS study assessed whether a rest study was needed or not or if he/she was uncertain and wanted to consult a physician. After that, the physician in charge interpreted the images and decided whether a rest study was required or not. Results The nuclear medicine technologists and the physicians in clinical routine agreed in 103 of the 107 cases (96%) for which the technologists felt certain regarding the need for a rest study. In the remaining 14 cases the technologists were uncertain, i.e. wanted to consult a physician. The agreement between the technologists and the physicians in clinical routine was very good, resulting in a kappa value of 0.92. There was no statistically significant difference in the evaluations made by technicians and physicians (P = 0.617). Conclusions The nuclear medicine technologists were able to accurately determine whether a rest study was necessary. There was very good agreement between nuclear medicine technologists and physicians in the assessment of the need for a rest study. If the technologists can make this decision, the effectiveness of the nuclear medicine department will improve.
Art Blended Research and Children’s Gender Identity Making  [PDF]
Camilla H?llgren
Creative Education (CE) , 2015, DOI: 10.4236/ce.2015.622240
Abstract: The intention with this article is to explore how visuals and written text may combine to further understandings about complex matters such as gendered aspects of the human condition. To do so, I bring together my professional practices as researcher and artist by theorizing, conceptualizing and visualizing aspects of children’s gender identity making. As such, this article is conceptual rather than empirical and covers issues about learning, existentialism, social constructivism, children, identity, and gender. It also exemplifies what I call Art Blended Research, an approach that draws on the insight of that there is more to see than meets the eye. In conclusion, the strength of this approach does not lie in the ability to explain what is. Instead, the strength of Art Blended Research is found in possible explorations and inspirations of what might be.
Negotiating figurations for feminist methodologies - a manifest for the fl@neur
Jennie Olofsson
Graduate Journal of Social Science , 2008,
Abstract:
Local Riemann Hypothesis for complex numbers
Rikard Olofsson
Mathematics , 2006,
Abstract: In this paper a special class of local zeta functions is studied. The main theorem states that the functions have all zeros on the line Re (s)=1/2. This is a natural generalization of the result of Bump and Ng stating that the zeros of the Mellin transform of Hermite functions have Re (s)=1/2.
A computation of Poisson kernels for some standard weighted biharmonic operators in the unit disc
Anders Olofsson
Mathematics , 2007,
Abstract: We compute Poisson kernels for integer weight parameter standard weighted biharmonic operators in the unit disc with Dirichlet boundary conditions. The computations performed extend the supply of explicit examples of such kernels and suggest similar formulas for these Poisson kernels to hold true in more generality. Computations have been carried out using the open source computer algebra package Maxima.
Large supremum norms and small Shannon entropy for Hecke eigenfunctions of quantized cat maps
Rikard Olofsson
Mathematics , 2007, DOI: 10.1007/s00220-008-0627-x
Abstract: This paper concerns the behavior of eigenfunctions of quantized cat maps and in particular their supremum norm. We observe that for composite integer values of N, the inverse of Planck's constant, some of the desymmetrized eigenfunctions have very small support and hence very large supremum norm. We also prove an entropy estimate and show that our functions satisfy equality in this estimate. In the case when N is a prime power with even exponent we calculate the supremum norm for a large proportion of all desymmetrized eigenfunctions and we find that for a given N there is essentially at most four different values these assume.
A Brownian optimal switching problem under incomplete information
Marcus Olofsson
Mathematics , 2015,
Abstract: In this paper we study an incomplete information optimal switching problem in which the manager only has access to noisy observations of the underlying Brownian motion $\{W_t\}_{t \geq 0}$. The manager can, at a fixed cost, switch between having the production facility open or closed and must find the optimal management strategy using only the noisy observations. Using the theory of linear stochastic filtering, we reduce the incomplete information problem to a full information problem, show that the value function is non-decreasing with the amount of information available, and that the value function of the incomplete information problem converges to the value function of the corresponding full information problem as the noise in the observed process tends to $0$.
Size-biased branching population measures and the multi-type $x\log x$ condition
Peter Olofsson
Statistics , 2010, DOI: 10.3150/09-BEJ211
Abstract: We investigate the $x\log x$ condition for a general (Crump--Mode--Jagers) multi-type branching process with a general type space by constructing a size-biased population measure that relates to the ordinary population measure via an intrinsic martingale $W_t$. Sufficiency of the $x\log x$ condition for a non-degenerate limit of $W_t$ is proved and conditions for necessity are investigated.
The mid-infrared extinction in molecular clouds Case study of B 335
Sven Olofsson,G?ran Olofsson
Physics , 2011, DOI: 10.1051/0004-6361/201015564
Abstract: The purpose of the investigation is to probe the dust properties inside a molecular cloud, how particle grow and how the presence of ice coatings may change the overall shape of the extinction curve. Field stars can be used to probe the cloud extinction. By combining multi-colour photometry and IR spectroscopy the spectral class of the star can be determined as can the extinction curve. We determine the reddening curve from 0.35 to 24 \mu m. The water ice band at 3.1 \mu m is weaker (\tau(3.1) = 0.4) than expected from the cloud extinction (AV \approx 10 for the sightline to the most obscured star). On the other hand, the CO ice band at 4.7 \mu m is strong (\tau(4.67) = 0.7) and indicates, that the mass column density of frozen CO is about the same as that of water ice. We show that the reddening curves for the two background stars, for which the silicate band has been measured, can be accurately modelled from the UV to 24 \mu m. These models only include graphite and silicate grains. No need for any additional major grain component to explain the slow decline of the reddening curve beyond the K band. The dust model for the dense part of the cloud has more large grains than for the rim. We propose that the well established shallow reddening curve beyond the K band has two different explanations: larger graphite grains in dense regions and relatively small grains in the diffuse ISM, giving rise to substantially less extinction beyond the K band than previously thought. For the sight line towards the most obscured star, we derive the relation AKs = 0.97 \cdot E(J - Ks), and assuming that all silicon is bound in silicates, N(2 H2 +H) \approx 1.5 \times 10^{21} \cdot AV \approx 9 \times 10^{21} \cdot AKs. For the rim of the cloud we get AKs = 0.51 \cdot E(J - Ks), which is close to recent determinations for the diffuse ISM. The corresponding gas column density is N(2 H2 +H) \approx 2.3 \times 10^{21} \cdot AV \approx 3 \times 10^{22} \cdot AKs.
The extinction law for molecular clouds. Case study of B 335
Sven Olofsson,G?ran Olofsson
Physics , 2011, DOI: 10.1051/0004-6361/201014174
Abstract: We determine the extinction curve from the UV to the near-IR for molecular clouds and investigate whether current models can adequately explain this wavelength dependence of the extinction. The aim is also to interpret the extinction in terms of H2 column density. We applied five different methods, including a new method for simultaneously determining the reddening law and the classification of the background stars. Our method is based on multicolour observations and a grid of model atmospheres. We confirm that the extinction law can be adequately described by a single parameter, RV (the selective to absolute extinction), in accordance with earlier findings. The RV value for B 335 is RV = 4.8. The reddening curve can be accurately reproduced by model calculations. By assuming that all the silicon is bound in silicate grains, we can interpret the reddening in terms of column density, NH = 4.4 (\pm0.5) \times 1021 EI-Ks cm-2, corresponding to NH = 2.3 (\pm0.2) \times 1021 \cdot AV cm-2, close to that of the diffuse ISM, (1.8-2.2) \times 1021 cm-2 . We show that the density of the B 335 globule outer shells can be modelled as an evolved Ebert-Bonnor gas sphere with {\rho} \propto r-2, and estimate the mass of this globule to 2.5 Msun
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