| 1. |
- Bruzzi, M, et al.
(författare)
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Radiation-hard semiconductor detectors for SuperLHC
- 2005
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 541:1-2, s. 189-201
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Tidskriftsartikel (refereegranskat)abstract
- An option of increasing the luminosity of the Large Hadron Collider (LHC) at CERN to 1035 cm-2 s-1 has been envisaged to extend the physics reach of the machine. An efficient tracking down to a few centimetres from the interaction point will be required to exploit the physics potential of the upgraded LHC. As a consequence, the semiconductor detectors close to the interaction region will receive severe doses of fast hadron irradiation and the inner tracker detectors will need to survive fast hadron fluences of up to above 1016cm-2. The CERN-RD50 project "Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders" has been established in 2002 to explore detector materials and technologies that will allow to operate devices up to, or beyond, this limit. The strategies followed by RD50 to enhance the radiation tolerance include the development of new or defect engineered detector materials (SiC, GaN, Czochralski and epitaxial silicon, oxygen enriched Float Zone silicon), the improvement of present detector designs and the understanding of the microscopic defects causing the degradation of the irradiated detectors. The latest advancements within the RD50 collaboration on radiation hard semiconductor detectors will be reviewed and discussed in this work.
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| 2. |
- Luan, Shi-Lu, et al.
(författare)
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Multilocus sequence typing of Swedish invasive group B streptococcus isolates indicates a neonatally associated genetic lineage and capsule switching.
- 2005
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Ingår i: Journal of clinical microbiology. - 0095-1137 .- 1098-660X. ; 43:8, s. 3727-33
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Tidskriftsartikel (refereegranskat)abstract
- Streptococcus agalactiae, also designated group B streptococcus (GBS), is an important pathogen in neonates, pregnant women, and nonpregnant adults with predisposing conditions. We used multilocus sequence typing (MLST) to characterize 158 GBS isolates that were associated with neonatal and adult invasive disease and that were collected in northern and western Sweden from 1988 to 1997. Five major genetic lineages (sequence type [ST] 19, ST-17, ST-1, ST-23, and ST-9 complexes) were identified among the isolates, including serotype Ia, Ib, and II to V isolates, indicating a highly clonal population structure among invasive GBS isolates. A number of STs were found to contain isolates of different serotypes, which indicates that capsule switching occurred rather frequently. Two distantly related genetic lineages were identified among isolates of serotype III, namely, clonal complex 19 (CC19), and CC17. CC19 was equally common among isolates from adult and neonatal disease (accounting for 10.3% of GBS isolates from adult disease and 18.7% from neonatal disease), whereas CC17 significantly appeared to be associated with neonatal invasive disease (isolated from 21.9% of neonatal isolates but only 2.6% of adult isolates). The distribution of the mobile elements GBSi1 and IS1548 reveals that they can act as genetic markers for lineages CC17 and CC19, respectively.
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| 3. |
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| 4. |
- Palmgren, Helena, 1955-, et al.
(författare)
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Salmonella in Black-headed gulls ( Larus ridibundus); prevalence, genotypes and influence on Salmonella epidemiology.
- 2006
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Ingår i: Epidemiology and Infection. - 0950-2688 .- 1469-4409. ; 134:3, s. 635-644
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Tidskriftsartikel (refereegranskat)abstract
- During a period of 3 years, 1998-2000, 1047 faecal swabs from Black-headed gulls were sampled at one location in Southern Sweden. Salmonella spp. was found in 28 individuals (2.7%) and the dominating serotype found was S. Typhimurium (83%). Twenty-five per cent of the Salmonella-infected gulls were later recaptured and re-sampled. We found that Salmonella infection in Black-headed gulls was of short duration, and that infection in this bird species was predominantly expressed as carriage without disease manifestations. All S. Typhimurium isolates were subjected to antibiotic resistance profiling and molecular characterization by pulsed-field gel electrophoresis and IS200 polymerase chain reaction. The S. Typhimurium gull isolates were compared to human and domestic animal isolates of the same serotype and phage type. We found genetic relatedness of S. Typhimurium DT195 isolates from gulls, domestic animals and humans, indicating that Black-headed gulls might play a role in the spread of S. Typhimurium in Sweden.
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| 5. |
- Wilkens, Carl, 1968-
(författare)
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Auri sacra fames : Interest Rates -- Prediction, Jumps and the Market Price of Risk
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis consists of three essays investigating different aspects of interest rates."Prediction of Future Risk-Neutral Short-Term Interest Rate Densities: Can the Black, Derman and Toy Model Assist?" (Co-authored with David Vestin.) This essay evaluates two different approaches to inferring expectations of future interest rates from asset prices. One is based on bond data and builds on the Black, Derman and Toy model, the other is based on option prices. We compare the outcome with a specified assumed benchmark data generating process. The main conclusion is that the option based model works well, whereas the bond based model has difficulties in capturing aspects of the true distribution."Natura non facit saltum – Or Are Jumps an Inherent Feature in European Interest Rate Markets?" A jump-enhanced diffusion model for the instantaneous interest rate is estimated on the EURIBOR, LIBOR and STIBOR one-week interest rates via the characteristic function and a Fourier transform to recover the density function. This is compared with an estimated non-jump diffusion model. Both continuous-time and discrete-time versions of the model are estimated. For all three interest rate series, likelihood ratio tests favor the jump-enhanced model at a statistically significant level. This result holds for both the continuous-time and the discrete-time versions of the model."Estimating the Market Price of Risk in European Interest Rate Markets Using Spectral GMM." The market price of risk in European interest rate markets, constituted by the market price of diffusion risk and the market price of jump risk, is estimated for a jump diffusion model, using the characteristic function and the Generalized Method of Moments. Utilized data is the EURIBOR twelve-month interest rate during 1999-2003. The results are in line with earlier studies on US interest rate markets. The estimation technique appears promising in its technical simplicity, but entails practical estimation difficulties such as start-value sensitivity and lack of efficiency.
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