| 1. |
- Anglart, Henryk, et al.
(författare)
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EXPERIMENTAL INVESTIGATION OF STATIONARY AND TRANSIENT POST-DRYOUT HEAT TRANSFER IN 22.1X10 MM ANNULUS WITH SPACERS
- 2005
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Ingår i: Proceedings of the Eleventh International Topical Meeting on Nuclear Reactor Thermal-Hydraulics.
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Konferensbidrag (refereegranskat)abstract
- Experimental investigation of the post-dryout heat transfer in annulus test section has been performed in the high-pressure two-phase loop at the Royal Institute of Technology (KTH). The test section has an annular geometry with 10 mm rod outer diameter and 22.1 mm tube inner diameter. Seven spacers are located along the test section to keep the rod and the tube equidistant along the test section. Both the tube and the rod are manufactured of Inconel 600 to withstand high temperatures. Several thermocouples have been installed on the tube and the rod surface to measure the local temperature.The measurements have been performed for a wide range of the inlet mass flow rate, keeping the inlet subcooling equal to 10 K and the pressure to 70 bars. Uniform axial power distributions have been applied on the rod and tube walls, however, several different ratios between the heat fluxes on the two surfaces have been applied. Both steady-state and transient measurements have been performed in which axial distribution of wall temperatures have been registered.The experiments indicate a very strong influence of spacers on post-dryout heat transfer. In particular, for several cases with relatively low local quality the dryout spot is limited to a direct proximity of spacers, stretching from approximately 10 cm upstream of the spacer to 5 cm downstream of the spacer. Only for relatively high powers the dryout patch could cover the whole distance between two neighboring spacers.
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| 4. |
- Hedberg, Per, 1955, et al.
(författare)
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Energisparande
- 2005
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Ingår i: Holmberg Sören och Weibull Lennert (red). Lyckan kommer, lyckan går. Göteborgs universitet. SOM-institutet. - 0284-4788. - 9189673069 ; , s. 115-122
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Hedberg, Per-Henrik, et al.
(författare)
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Investigating correct and incorrect statements of eyewitness testimony using semantic spaces
- 2009
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Ingår i: 21st Annual Convention of the Association for Psychological Science, San Francisco, 2009. ; , s. 81-81
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Studies have shown that descriptions of real and suggested or fabricated eyewitness memory may differ in ways that could be explained by differences in the formation and cognitive representations of these memories. However, the characteristics of an eyewitness’ description are likely to depend not only on the cognitive features of memory, but also on the witness’ social motivation to display meta-cognitive states to the investigator. For example, when a response to a question is delayed, this delay is open to several interpretations. It may mean that the respondent a) have difficulty understanding the question b) is retrieving the information c) is formulating her response d) is withdrawing from the interaction. To prevent misunderstanding, respondents need to account for their delays, uncertainties, and failures in answering. Linguistic research shows that when responding to general knowledge questions, people do this by using several markers (Brennan & Williams, 1995; Krahmer & Swerts, 2005; Smith & Clark, 1993). Respondents often use fillers like “uh” and “um” to indicate some trouble with processing. The fillers both signal the delay and offer a brief account for it. Lack of confidence can either be implied by rising intonation, or by hedges as “I think”, “I guess”, etc. Respondents can also account for delays with self-talk and explicit commentary. Both fillers and self-talk are showing the questioner that despite the delay, one is still actively trying to retrieve an answer. Both are ways to let the questioner in on how the retrieval is progressing, and show that the respondent is not uncooperative, ignorant, poor in judgment etc. Listeners have been shown to use these cues to make adequate assessments of the certainty or uncertainty of the speaker (Brennan & Williams, 1995; Krahmer & Swerts, 2005; 2006). This constitutes the Interactive view on question answering (Smith & Clark, 1993). The current research investigated whether similar communicative cues discriminated eyewitnesses’ accurate and inaccurate responses to questions about a crime event. Furthermore, we examined the extent to which groups differing in experience with judging eyewitness memory use these cues to estimate witness accuracy. Witnesses were videotaped while being interviewed about their memory of a simulated crime scenario. Responses to cued recall questions that provided correct or incorrect information about a specific detail were protocoled and scored with respect to linguistic and paralinguistic uncertainty cues (delays, fillers non-words/words, hedges, number of words). Results confirmed a higher frequency of “uncertainty” cues in witnesses’ incorrect as compared to correct responses. This finding points to the importance of taking the interactive component of the question-answering situation into account when analysing eyewitness memory. The eyewitness statements were presented to police detectives, chief judges, and lay-persons in written or in videotaped format. While all groups had difficulty determining accuracy, experienced police detectives, but not judges, had a better discrimination accuracy than lay-persons. Both professionals and lay-persons showed better discrimination when presented with statements in written than in videotaped format. This suggests that the visual format conveys information that interferes with the detection of valid accuracy cues.
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| 6. |
- Hedberg, Per, 1955
(författare)
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Högradioaktivt ämne.
- 2009
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Ingår i: Holmberg, Sören och Weibull, Lennart (red). Svensk höst. Göteborgs universitet. SOM-institutet.. - 0284-4788. - 9789189673168 ; , s. 259-266
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 7. |
- Hedberg, Per, 1955
(författare)
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Rekordlågt valdeltagande
- 2006
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Ingår i: Oscarsson Henrik och Holmberg Sören med bidrag av Hedberg Per och Dahlberg Stefan. Europaval. Göteborgs universitet. Statsvetenskapliga institutionen. ; , s. 25-59
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 8. |
- Hedberg, Per, 1955
(författare)
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Sol, vind och vågor
- 2007
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Ingår i: Holmberg Sören och Weibull Lennart (red). Det nya Sverige. Göteborgs universitet. SOM-institutet.. - 0284-4788. - 9789189673113 ; , s. 303-316
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Hedberg, Per, 1955
(författare)
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Svenska folket tycker om sol och vind
- 2005
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Ingår i: Holmberg Sören & Weibull Lennart (red). Lyckan kommer, lyckan går. Göteborgs universitet. SOM-institutet.. - Göteborg : SOM-institutet, Göteborg University. - 0284-4788. - 9189673069 ; , s. 221-230
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 10. |
- Hedberg, Per, 1955
(författare)
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Svenska folket vill ha mer vindkraft
- 2006
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Ingår i: Holmberg Sören och Weibull Lennart (red). Du stora nya värld. Göteborgs universitet. SOM-institutet.. - 0284-4788. - 9189673093 ; , s. 279-286
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 16. |
- Hedberg, Per, 1955
(författare)
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Vindkraft på frammarch
- 2008
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Ingår i: Holmberg, Sören och Weibull, Lennart (red) Skilda världar. Göteborg. SOM-institutet.. - Göteborg : University of Gothenburg. - 0284-4788. ; , s. 213-226
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 18. |
- Hedberg, Sara Thulin, et al.
(författare)
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Antibiotic susceptibility and characteristics of Neisseria meningitidis isolates from the African meningitis belt, 2000 to 2006 : phenotypic and genotypic perspectives
- 2009
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Ingår i: Antimicrobial Agents and Chemotherapy. - 0066-4804 .- 1098-6596. ; 53:4, s. 1561-1566
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Tidskriftsartikel (refereegranskat)abstract
- Up-to-date information regarding the antibiotic susceptibility of Neisseria meningitidis strains from African countries is highly limited. Our aim was to comprehensively describe the antibiotic susceptibilities of a selection of N. meningitidis isolates recovered between 2000 and 2006 from 18 African countries, mainly those within the meningitis belt. Susceptibilities to 11 antibiotics were determined using Etest for 137 N. meningitidis isolates (stringently selected from 693 available isolates). The isolates were also characterized by serogrouping, multilocus sequence typing, genosubtyping, and penA allele identification. All N. meningitidis isolates were susceptible to ceftriaxone, chloramphenicol, and ciprofloxacin. No isolate produced beta-lactamase. Only three isolates (2%) displayed reduced susceptibility to penicillin G. The two isolates with the highest penicillin G MICs were the only isolates showing reduced susceptibility to ampicillin and cefuroxime. One of these isolates was also resistant to penicillin V. One percent of isolates displayed reduced susceptibility to rifampin, while 52% of the isolates were resistant to tetracycline, 74% were resistant to erythromycin, and 94% were resistant to sulfadiazine. The MICs of rifampin and tetracycline seemed to be associated with the serogroup of the isolates. In total, 18 sequence types (STs), 10 genosubtypes, and 8 different penA alleles were identified; the most common were ST-7, P1.20,9,35-1, and penA4, respectively. A high level of correlation was found between ST, genosubtype, and penA allele. In conclusion, N. meningitidis isolates from the African meningitis belt remain highly susceptible to the antibiotics used. Regarding beta-lactam antibiotics, rare isolates showed a reduced susceptibility to penicillins, but the expanded-spectrum cephalosporins are not affected at present.
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| 19. |
- Hedberg, Sara Thulin, et al.
(författare)
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Combined real-time PCR and pyrosequencing strategy for objective, sensitive, specific, and high throughput identification of reduced susceptibility to penicillins in Neisseria meningitidis
- 2008
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Ingår i: Antimicrobial Agents and Chemotherapy. - Washington, DC : American Society for Microbiology. - 0066-4804 .- 1098-6596. ; 52:2, s. 753-756
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Tidskriftsartikel (refereegranskat)abstract
- A segment of penA in Neisseria meningitidis strains (n = 127), including two nucleotide sites closely associated to reduced susceptibility to penicillins, was amplified and pyrosequenced. All results were in concordance with Sanger sequencing, and a high correlation between alterations in the two Pen(i)-specific sites and reduced susceptibility to penicillins was identified.
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| 23. |
- Jacobsson, Susanne, 1974-, et al.
(författare)
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Prevalence and sequence variations of the genes encoding the five antigens included in the novel 5CVMB vaccine covering group B meningococcal disease
- 2009
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Ingår i: Vaccine. - Amsterdam : Elsevier. - 0264-410X .- 1873-2518. ; 27:10, s. 1579-1584
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Tidskriftsartikel (refereegranskat)abstract
- During the recent years, projects are in progress for designing broad-range non-capsular-based meningococcal vaccines, covering also serogroup B isolates. We have examined three genes encoding antigens (NadA, GNA1030 and GNA2091) included in a novel vaccine, i.e. the 5 Component Vaccine against Meningococcus B (5CVMB), in terms of gene prevalence and sequence variations. These data were combined with the results from a similar study, examining the two additional antigens included in the 5CVMB (fHbp and GNA2132).nadA and fHbp v. 1 were present in 38% (n=36), respectively 71% (n=67) of the isolates, whereas gna2132, gna1030 and gna2091 were present in all the Neisseria meningitidis isolates tested (n=95). The level of amino acid conservation was relatively high in GNA1030 (93%), GNA2091 (92%), and within the main variants of NadA and fHbp. GNA2132 (54% of the amino acids conserved) appeared to be the most diversified antigen. Consequently, the theoretical coverage of the 5CVMB antigens and the feasibility to use these in a broad-range meningococcal vaccine is appealing.
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| 24. |
- Ou, Gangwei, et al.
(författare)
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Proximal small intestinal microbiota and identification of rod-shaped bacteria associated with childhood celiac disease
- 2009
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Ingår i: American Journal of Gastroenterology. - : Ovid Technologies (Wolters Kluwer Health). - 0002-9270 .- 1572-0241. ; 104:12, s. 3058-3067
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Alterations in the composition of the microbiota in the intestine may promote development of celiac disease (CD). Using scanning electron microscopy (SEM) we previously demonstrated that rod-shaped bacteria were present on the epithelium of proximal small intestine in children with CD but not in controls. In this study we characterize the microbiota of proximal small intestine in children with CD and controls and identify CD-associated rod-shaped bacteria. METHODS: Proximal small intestine biopsies from 45 children with CD and 18 clinical controls were studied. Bacteria were identified by 16S rDNA sequencing in DNA extracted from biopsies washed with buffer containing dithiothreitol to enrich bacteria adhering to the epithelial lining, by culture-based methods and by SEM and transmission electron microscopy. RESULTS: The normal, mucosa-associated microbiota of proximal small intestine was limited. It was dominated by the genera Streptococcus and Neisseria, and also contained Veillonella, Gemella, Actinomyces, Rothia, and Haemophilus. The proximal small intestine microbiota in biopsies from CD patients collected during 2004-2007 differed only marginally from that of controls, and only one biopsy (4%) had rod-shaped bacteria by SEM (SEM+). In nine frozen SEM+ CD biopsies from the previous study, microbiotas were significantly enriched in Clostridium, Prevotella, and Actinomyces compared with SEM- biopsies. Bacteria of all three genera were isolated from children born during the Swedish CD epidemic. New Clostridium and Prevotella species and Actinomyces graevenitzii were tentatively identified. CONCLUSIONS: Rod-shaped bacteria, probably of the indicated species, constituted a significant fraction of the proximal small intestine microbiota in children born during the Swedish CD epidemic and may have been an important risk factor for CD contributing to the fourfold increase in disease incidence in children below 2 years of age during that time.
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| 25. |
- Taha, Muhamed-Kheir, et al.
(författare)
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Defining the breakpoint for resistance to rifampicin in Neisseria meningitidis by rpoB sequencing
- 2009
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Clinical isolates of Neisseria meningitidis resistant to rifampicin are important to identify asthey lead to failure of chemoprophylaxis of meningococcal disease. However, theidentification of these isolates is hindered by the absence of a harmonized breakpoint despiteefforts of standardization. In the present study, a large number (n=352) of clinical N.meningitidis isolates from 12 mainly European countries and spanning over 25 years (1984 to2009) were examined. The collection comprised all clinical isolates with MIC 0.25 mg/lreceived by the national reference laboratories for meningococci in the participating countries(n=161). In addition, representative isolates displaying MIC of rifampicin <0.25 mg/l wereexamined (n=191). Phenotyping and genotyping of isolates were performed and a 660 bpDNA fragment of the rpoB gene was sequenced in all the included isolates. Sequencesdiffering by at least one nucleotide were defined as a unique rpoB allele (n=55). Geometricmeans of MIC were calculated for isolates displaying the same allele. All the clinical isolatesdisplaying MIC >1 mg/l of rifampicin possessed rpoB alleles with critical mutations (in total21 alleles), resulting in substitutions at the codon H552 and less frequently at nearby codons(S548 and S557). These alterations were absent in the alleles (n=34) found in all isolates withMIC 1 mg/l. Based on these findings, rifampicin susceptible isolates could be defined asthose with MIC 1 mg/l. A new web site was created based on the data from this work (http://neisseria.org/nm/typing/rpoB). The rifampicin resistant isolates belonged to diversegenetic lineages and provoked lower bacteremia levels in mice. This biological cost mayexplain the non-expansion of the rifampicin resistant isolates.
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| 26. |
- Thulin Hedberg, Sara
(författare)
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Antibiotic susceptibility and resistance in Neisseria meningitidis : phenotypic and genotypic characteristics
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Neisseria meningitidis, also known as the meningococcus, is a globally spread obligate human bacterium causing meningitis and/or septicaemia. It is responsible for epidemics in both developed and developing countries. Untreated invasive meningococcal disease is often fatal, and despite modern intensive care units, the mortality is still remarkably high (approximately 10%). The continuously increasing antibiotic resistance in many bacterial pathogens is a serious public health threat worldwide and there have been numerous reports of emerging resistance in meningococci during the past decades. In paper I, the gene linked to reduced susceptibility to penicillins, the penA gene, was examined. The totally reported variation in all published penA genes was described. The penA gene was highly variable (in total 130 variants were identified). By examination of clinical meningococcal isolates, the association between penA gene sequences and penicillin susceptibility could be determined. Isolates with reduced susceptibility displayed mosaic structures in the penA gene. Two closely positioned nucleotide polymorphisms were identified in all isolates with reduced penicillin susceptibility and mosaic structured penA genes. These alterations were absent in all susceptible isolates and were successfully used to detect reduced penicillin susceptibility by real-time PCR and pyrosequencing in paper II. In papers III and IV, antibiotic susceptibility and characteristics of Swedish and African meningitis belt meningococcal isolates were comprehensively described. Although both populations were mainly susceptible to the antibiotics used for treatment and prophylaxis, the proportion of meningococci with reduced penicillin susceptibility was slightly higher in Sweden. A large proportion of the African isolates was resistant to tetracycline and erythromycin. In paper V, the gene linked to rifampicin resistance, the rpoB gene, was examined in meningococci from 12 mainly European countries. Alterations of three amino acids in the RpoB protein were found to always and directly lead to rifampicin resistance. A new breakpoint for rifampicin resistance in meningococci was suggested. The biological cost of the RpoB alterations was investigated in mice. The pathogenicity/virulence was significantly lower in rifampicin resistant mutants as compared with susceptible wild-type bacteria.
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