| 1. |
- Bruzzi, M, et al.
(author)
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Radiation-hard semiconductor detectors for SuperLHC
- 2005
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In: 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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Journal article (peer-reviewed)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. |
- Davydova, B., et al.
(author)
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Coxsackievirus immunization delays onset of diabetes in non-obese diabetic mice
- 2003
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In: Journal of Medical Virology. - : Wiley. - 0146-6615 .- 1096-9071. ; 69:4, s. 510-520
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Journal article (peer-reviewed)abstract
- Enteroviruses may be involved in the pathogenesis of Type 1 diabetes through different mechanisms including triggering of autoimmunity. The effect of immunization with coxsackievirus B4-E2 on diabetes incidence was studied in the non-obese diabetic mice, an animal model for human autoimmune insulin-dependent diabetes mellitus. The immunization delayed the onset of diabetes in the mice, and the effect was mediated at least partially by virus immunization-activated splenocytes as demonstrated by adoptive transfer experiments. Immunization resulted in a strong humoral immune response against the immunizing virus, formalin-inactivated coxsackievirus B4-E2. Cell-mediated immune responseto virus antigen was characterised by interferon gamma and interleukin 10 secretion. The immunization also resulted in increased antibody levels against several beta-cell autoantigens. By using epitope mapping we were able to show that in addition to reactivity with the known epitopes of viral proteins and tyrosine phosphatase A-2 or heat shock protein 60, responses to some other regions of autoantigens were enhanced. In preproinsulin, the response was restricted against an antigenic region earlier identified as DR4-dependent epitope. This reactivity can not be explained by homologous amino acid sequences and it is possible that enterovirus immunization might change the autoantigen specific TH1/TH2 balance in non-obese diabetic mice. In conclusion, our results suggest that coxsackievirus immunization increased humoral immune response to beta cell autoantigens and this was associated with a less destructive pathology for spontaneous diabetes in non-obese diabetic mice. © 2003 Wiley-Liss, Inc.
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| 3. |
- Harkonen, T, et al.
(author)
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Enterovirus infection may induce humoral immune response reacting with islet cell autoantigens in humans
- 2003
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In: Journal of Medical Virology. - : Wiley. - 0146-6615 .- 1096-9071. ; 69:3, s. 426-440
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Journal article (peer-reviewed)abstract
- Molecular mimicry is one of the mechanisms by which enterovirus infections have been postulated to have a role in the pathogenesis of type 1 diabetes. Immunogenic epitopes in enterovirus capsid protein VP1 and procapsid protein VP0 have sequence similarities with diabetes-associated epitopes in tyrosine phosphatase IA-2/IAR and heat shock protein 60. In the present study, documented enterovirus infection was shown to induce humoral responses, that in 7% and 1% of patients cross-reacted with the known diabetes-associated epitopes in tyrosine phosphatase IAR and heat shock protein 60, respectively. In contrast, none of the children vaccinated against poliomyelitis had antibodies to the diabetes-associated epitope of tyrosine phosphatases IA-2/IAR. The antibody response studied in serum samples from six patients with coxsackievirus A9 infection was mainly targeted to capsid protein VP1. Coxsackievirus A9 infection induced antibodies cross-reacted with one epitope in heat shock protein 60, but not with epitopes derived from other autoantigens. Most diabetic children had high levels of antibodies to both coxsackievirus and poliovirus derived VP1 peptides but the pattern of reactivity did not differ from that seen in healthy children. The reactivity of linear epitopes derived from autoantigens was low in general and associated with the presence of multiple autoantibodies in the patients. Some linear auto-epitopes derived from tyrosine phosphatase IA-2, glutamic acid decarboxylase 65, preproinsulin, and heat shock protein 60 were recognized by sera from diabetic patients, but not by sera from healthy children. In conclusion, enteroviruses may induce immune responses that react with islet cell autoantigens, which is a concern when a putative inactivated enterovirus vaccine is considered.
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| 4. |
- Liu, X. D., et al.
(author)
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Origin and expansion of the world's most widespread pinniped: Range-wide population genomics of the harbour seal (Phoca vitulina)
- 2022
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In: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 31:6, s. 1682-1699
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Journal article (peer-reviewed)abstract
- The harbour seal (Phoca vitulina) is the most widely distributed pinniped, occupying a wide variety of habitats and climatic zones across the Northern Hemisphere. Intriguingly, the harbour seal is also one of the most philopatric seals, raising questions as to how it colonized its current range. To shed light on the origin, remarkable range expansion, population structure and genetic diversity of this species, we used genotyping-by-sequencing to analyse similar to 13,500 biallelic single nucleotide polymorphisms from 286 individuals sampled from 22 localities across the species' range. Our results point to a Northeast Pacific origin of the harbour seal, colonization of the North Atlantic via the Canadian Arctic, and subsequent stepping-stone range expansions across the North Atlantic from North America to Europe, accompanied by a successive loss of genetic diversity. Our analyses further revealed a deep divergence between modern North Pacific and North Atlantic harbour seals, with finer-scale genetic structure at regional and local scales consistent with strong philopatry. The study provides new insights into the harbour seal's remarkable ability to colonize and adapt to a wide range of habitats. Furthermore, it has implications for current harbour seal subspecies delineations and highlights the need for international and national red lists and management plans to ensure the protection of genetically and demographically isolated populations.
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| 5. |
- Brault, Emily K., et al.
(author)
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Trophic position and foraging ecology of Ross, Weddell, and crabeater seals revealed by compound-specific isotope analysis
- 2019
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In: Marine Ecology Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 611, s. 1-18
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Journal article (peer-reviewed)abstract
- © The authors 2019. Ross seals Ommatophoca rossii are one of the least studied marine mammals, with little known about their foraging ecology. Research to date using bulk stable isotope analysis suggests that Ross seals have a trophic position intermediate between that of Weddell Leptonychotes weddellii and crabeater Lobodon carcinophaga seals. However, consumer bulk stable isotope values not only reflect trophic dynamics, but also variations in baseline isotope values, which can be substantial. We used compound-specific isotope analysis of amino acids (CSI-AA) to separate isotopic effects of a shifting baseline versus trophic structure on the foraging ecology of these ecologically important Antarctic pinnipeds. We found that Ross seals forage in an open ocean food web, while crabeater and Weddell seals forage within similar food webs closer to shore. However, isotopic evidence suggests that crabeater seals are likely following sea ice, while Weddell seals target productive areas of the continental shelf of West Antarctica. Our CSI-AA data indicate that Ross seals have a high trophic position equivalent to that of Weddell seals, contrary to prior conclusions from nitrogen isotope results on bulk tissues. CSI-AA indicates that crabeater seals are at a trophic position lower than that of Ross and Weddell seals, consistent with a krill-dominated diet. Our results redefine the view of the trophic dynamics and foraging ecology of the Ross seal, and also highlight the importance of quantifying baseline isotope variations in foraging studies.
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| 6. |
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| 7. |
- Harkonen, T., et al.
(author)
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Collapse of a Marine Mammal Species Driven by Human Impacts
- 2012
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In: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 7:9
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Journal article (peer-reviewed)abstract
- Understanding historical roles of species in ecosystems can be crucial for assessing long term human impacts on environments, providing context for management or restoration objectives, and making conservation evaluations of species status. In most cases limited historical abundance data impedes quantitative investigations, but harvested species may have long-term data accessible from hunting records. Here we make use of annual hunting records for Caspian seals (Pusa caspica) dating back to the mid-19th century, and current census data from aerial surveys, to reconstruct historical abundance using a hind-casting model. We estimate the minimum numbers of seals in 1867 to have been 1-1.6 million, but the population declined by at least 90% to around 100,000 individuals by 2005, primarily due to unsustainable hunting throughout the 20th century. This collapse is part of a broader picture of catastrophic ecological change in the Caspian over the 20th Century. Our results combined with fisheries data show that the current biomass of top predators in the Caspian is much reduced compared to historical conditions. The potential for the Caspian and other similar perturbed ecosystems to sustain natural resources of much greater biological and economic value than at present depends on the extent to which a number of anthropogenic impacts can be harnessed.
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| 8. |
- Heidejorgensen, M. P., et al.
(author)
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LONG-TERM EFFECTS OF EPIZOOTIC IN HARBOR SEALS IN THE KATTEGAT-SKAGERRAK AND ADJACENT AREAS
- 1992
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In: Ambio. - 0044-7447. ; 21:8, s. 511-516
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Journal article (peer-reviewed)abstract
- Results from aerial surveys of hauled-out harbor seals, Phoca vitulina, in the entire Kattegat-Skagerrak, the Limfjord and the western part of the Baltic Sea in 1989-1991 are compared with results from surveys conducted soon after the seal epizootic in 1988. The results suggest that an increase in relative abundance of seals occurred between 1988 and 1991 in the Limfjord and in most parts of the Kattegat-Skagerrak. Pup production was assessed at selected localities in the Kattegat-Skagerrak during 1978-1991. Lowered rate of pup production occurred in 1989, the year after the epizootic. However, the pup production resembled expected values in 1990-1991. The decline in 1989 was probably due either to perturbations of the reproductive cycle caused by the morbilli virus infections in 1988, or to the shortage of mature males in some areas in the 1988 mating season. The lowered pup production was also evident in the aerial surveys where no increase in relative abundance was detected during 1988-1990. Simulations based on a matrix model of the Kattegat-Skagerrak population suggest that skewed sex and age distributions will persist for decades, but a high rate of increase should enable the population to recover by 1995-1996 to a size similar to that before the epizootic.
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| 9. |
- Hussein, T., et al.
(author)
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Evaluation and modeling of the size fractionated aerosol particle number concentration measurements nearby a major road in Helsinki - Part II : Aerosol measurements within the SAPPHIRE project
- 2007
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In: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 7:15, s. 4081-4094
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Journal article (peer-reviewed)abstract
- This study presents an evaluation and modeling exercise of the size fractionated aerosol particle number concentrations measured nearby a major road in Helsinki during 23 August-19 September 2003 and 14 January-11 February 2004. The available information also included electronic traffic counts, on-site meteorological measurements, and urban background particle number size distribution measurement. The ultrafine particle (UFP, diameter < 100 nm) number concentrations at the roadside site were approximately an order of magnitude higher than those at the urban background site during daytime and downwind conditions. Both the modal structure analysis of the particle number size distributions and the statistical correlation between the traffic density and the UFP number concentrations indicate that the UFP were evidently from traffic related emissions. The modeling exercise included the evolution of the particle number size distribution nearby the road during downwind conditions. The model simulation results revealed that the evaluation of the emission factors of aerosol particles might not be valid for the same site during different time.
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| 10. |
- Jonasson, Johan, 1966, et al.
(author)
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A Unifying Framework for Estimating Generation Time in Age-Structured Populations: Implications for Phylogenetics and Conservation Biology
- 2022
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In: American Naturalist. - : University of Chicago Press. - 0003-0147 .- 1537-5323. ; 200:1
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Journal article (peer-reviewed)abstract
- Generation time is a measure of the pace of life and is used to describe processes in population dynamics and evolution. We show that three commonly used mathematical definitions of generation time in age-structured populations can produce different estimates of up to several years for the same set of life history data. We present and prove a mathematical theorem that reveals a general order relation among the definitions. Furthermore, the exact population growth rate at the time of sampling influences estimates of generation time, which calls for attention. For phylogenetic estimates of divergence times between species, included demographic data should be collected when the population growth rate for each species is most common and typical. In conservation biology, demographic data should be collected during phases of population decline in declining species, contrary to common recommendations to use predisturbance data. The results can be used to improve the International Union for Conservation of Nature's recommendation in parameterizing models for evaluating threat categories of threatened species and to avoid underestimating extinction risk.
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