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- Andersson, August, et al.
(författare)
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(14)C-Based source assessment of soot aerosols in Stockholm and the Swedish EMEP-Aspvreten regional background site
- 2011
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 45:1, s. 215-222
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Tidskriftsartikel (refereegranskat)abstract
- Combustion-derived soot or black carbon (BC) in the atmosphere has a strong influence on both climate and human health. In order to propose effective mitigation strategies for BC emissions it is of importance to investigate geographical distributions and seasonal variations of BC emission sources. Here, a radiocarbon methodology is used to distinguish between fossil fuel and biomass burning sources of soot carbon (SC). SC is isolated for subsequent off-line (14)C quantification with the chemothermal oxidation method at 375 degrees C (CTO-375 method), which reflects a recalcitrant portion of the BC continuum known to minimize inadvertent inclusion of any non-pyrogenic organic matter. Monitored wind directions largely excluded impact from the Stockholm metropolitan region at the EMEP-Aspvreten rural station 70 km to the south-west. Nevertheless, the Stockholm city and the rural stations yielded similar relative source contributions with fraction biomass (f(biomass)) for fall and winter periods in the range of one-third to half. Large temporal variations in (14)C-based source apportionment was noted for both the 6 week fall and the 4 month winter observations. The f(biomass) appeared to be related to the SC concentration suggesting that periods of elevated BC levels may be caused by increased wood fuel combustion. These results for the largest metropolitan area in Scandinavia combine with other recent (14)C-based studies of combustion-derived aerosol fractions to suggest that biofuel combustion is contributing a large portion of the BC load to the northern European atmosphere.
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| 2. |
- Barbu, Andreea, et al.
(författare)
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Blood flow in endogenous and transplanted pancreatic islets in anesthetized rats : Effects of lactate and pyruvate
- 2012
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Ingår i: Pancreas. - 0885-3177 .- 1536-4828. ; 41:8, s. 1263-1271
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The objective of this study was to evaluate the effects of exogenously administered lactate and pyruvate on blood perfusion in endogenous and transplanted islets. METHODS: Anesthetized Wistar-Furth rats were given lactate or pyruvate intravenously, and regional blood perfusion was studied 3 or 30 minutes later with a microsphere technique. Separate rats received a 30-minute infusion of pyruvate or lactate into the portal vein before blood flow measurements. We also administered these substances to islet-implanted rats 4 weeks after transplantation and measured graft blood flow with laser Doppler flowmetry. The expression of monocarboxylate transporter 1 and lactate dehydrogenase A was analyzed. RESULTS: The expression of monocarboxylate transporter 1 and lactate dehydrogenase A was markedly up-regulated in transplanted as compared with endogenous islets. Administration of pyruvate, but not lactate, increased mesenteric blood flow after 3 minutes. Pyruvate decreased mesenteric blood flow after 30 minutes, whereas lactate decreased only islet blood flow. These responses were absent in transplanted animals. A continuous intraportal infusion of lactate or pyruvate increased selectively islet blood flow but did not affect blood perfusion of transplanted islets. CONCLUSIONS: Lactate and pyruvate affect islet blood flow through effects mediated by interactions between the liver and the nervous system. Such a response can help adjust the release of islet hormones during excess substrate concentrations.
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| 3. |
- Crooks, Lucy, et al.
(författare)
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Identification of Null Alleles and Deletions from SNP Genotypes for an Intercross Between Domestic and Wild Chickens
- 2013
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Ingår i: G3. - : Oxford University Press (OUP). - 2160-1836. ; 3:8, s. 1253-1260
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Tidskriftsartikel (refereegranskat)abstract
- We analyzed genotypes from similar to 10K single-nucleotide polymorphisms (SNPs) in two families of an F-2 intercross between Red Junglefowl and White Leghorn chickens. Possible null alleles were found by patterns of incompatible and missing genotypes. We estimated that 2.6% of SNPs had null alleles compared with 2.3% with genotyping errors and that 40% of SNPs in which a parent and offspring were genotyped as different homozygotes had null alleles. Putative deletions were identified by null alleles at adjacent markers. We found two candidate deletions that were supported by fluorescence intensity data from a 60K SNP chip. One of the candidate deletions was from the Red Junglefowl, and one was present in both the Red Junglefowl and White Leghorn. Both candidate deletions spanned protein-coding regions and were close to a previously detected quantitative trait locus affecting body weight in this population. This study demonstrates that the similar to 50K SNP genotyping arrays now available for several agricultural species can be used to identify null alleles and deletions in data from large families. We suggest that our approach could be a useful complement to linkage analysis in experimental crosses.
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| 4. |
- Frank, Jens, et al.
(författare)
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Predictability of repeated carnivore attacks on livestock favours reactive use of mitigation measures
- 2010
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Ingår i: Journal of Applied Ecology. - : Wiley. - 0021-8901 .- 1365-2664. ; 47, s. 166-171
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Tidskriftsartikel (refereegranskat)abstract
- Summary 1. Predation on livestock is one of the main reasons for low tolerance against large carnivores in many parts of the world. Measures to reduce the conflicts have been developed, but resources for using them are often scarce. If wildlife managers as well as farmers learn more about when the risk of predation on livestock is higher, they will be able to make more effective use of resources for reducing predation. 2. In this study, we tested the hypothesis that the risk of predation on livestock immediately after an attack is higher on the affected farm compared with other farms in the same area. Data on sheep predation by brown bear Ursus arctos, lynx Lynx lynx and wolf Canis lupus in Sweden 1998–2006 were used in the analysis. 3. Ondepredatedfarmstherewasapproximatelya55timeshigherriskforarepeatpredationevent within 12 months compared to any other farm in the same area. During the first 5 weeks, 63%, 60% and 50% of the repeat attacks had occurred. 4. Wesuggestthatthemainmechanismbehindrepeatattacksonlivestockisthatcarnivoresreturn to the kill site to feed on carrion. Where livestock are still present and unprotected at the kill site when the carnivore returns, the farms will suffer a higher likelihood of a further attack compared to livestock on other farms. This study uses data from Sweden but we argue that the pattern will be the same in any part of the world where the ranges of livestock and large carnivores overlap. 4. Synthesis and applications. As the risk of an attack is higher directly after an initial attack, it will be more cost-effective to implement measures designed to reduce livestock predation by large carni- vores at that time, i.e. within the following 5 weeks. Temporary proactive measures are usually simpler and cheaper than permanent deterrents and we recommend their use wherever resources are limited.
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| 8. |
- Johansson, Anna Maria, et al.
(författare)
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Genome-Wide Effects of Long-Term Divergent Selection
- 2010
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Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 6:11, s. e1001188-
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Tidskriftsartikel (refereegranskat)abstract
- To understand the genetic mechanisms leading to phenotypic differentiation, it is important to identify genomic regions under selection. We scanned the genome of two chicken lines from a single trait selection experiment, where 50 generations of selection have resulted in a 9-fold difference in body weight. Analyses of nearly 60,000 SNP markers showed that the effects of selection on the genome are dramatic. The lines were fixed for alternative alleles in more than 50 regions as a result of selection. Another 10 regions displayed strong evidence for ongoing differentiation during the last 10 generations. Many more regions across the genome showed large differences in allele frequency between the lines, indicating that the phenotypic evolution in the lines in 50 generations is the result of an exploitation of standing genetic variation at 100s of loci across the genome.
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| 9. |
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| 10. |
- Johansson, Peter, et al.
(författare)
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Effect of selenium and Q10 on the cardiac biomarker NT-proBNP
- 2013
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Ingår i: Scandinavian Cardiovascular Journal. - : Informa Healthcare. - 1401-7431 .- 1651-2006. ; 47:5, s. 281-288
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To investigate whether the effect of 48-month usage of coenzyme Q10 and selenium on cardiac function was different for participants with different levels of cardiac wall tension as measured by plasma levels of N-terminal natriuretic peptide (NT-proBNP) at baseline. Methods. A 48-month randomized double-blind controlled trial in a cohort of community-dwelling elderly (mean age 78 years) was carried out. A total of 443 participants were given coenzyme Q10 combined with selenium, or a placebo. NT-proBNP measured at baseline and 48 months was used to evaluate the cardiac wall tension. Results. After 48 months, supplementation of coenzyme Q10 and selenium had varying impacts depending on the severity of impairment of cardiac function. Analyses of the responses in the different quintiles of baseline NT-proBNP showed that those with active supplementation, and a plasma level of NT-proBNP in the second to fourth quintiles demonstrated significantly reduced NT-proBNP levels (p = 0.022) as well as cardiovascular mortality after 48 months (p = 0.006). Conclusion. Long-term supplementation of coenzyme Q10/selenium reduces NT-proBNP levels and cardiovascular mortality in those with baseline NT-proBNP in the second to fourth quintiles indicating those who gain from supplementation are patients with mild to moderate impaired cardiac function.
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