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- Larsson, Bengt, et al.
(författare)
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Molecular oxygen in the rho Ophiuchi cloud
- 2007
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Ingår i: Astronomy & Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 466:3, s. 5-
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Tidskriftsartikel (refereegranskat)abstract
- Context: Molecular oxygen, O2, has been expected historically to be an abundant component of the chemical species in molecular clouds and, as such, an important coolant of the dense interstellar medium. However, a number of attempts from both ground and from space have failed to detect O2 emission.Aims: The work described here uses heterodyne spectroscopy from space to search for molecular oxygen in the interstellar medium. Methods: The Odin satellite carries a 1.1 m sub-millimeter dish and a dedicated 119 GHz receiver for the ground state line of O2. Starting in 2002, the star forming molecular cloud core ρ Oph A was observed with Odin for 34 days during several observing runs.Results: We detect a spectral line at v_LSR =+3.5 km s-1 with Δ v_FWHM=1.5 km s-1, parameters which are also common to other species associated with ρ Oph A. This feature is identified as the O2 (NJ = 11 - 1_0) transition at 118 750.343 MHz.Conclusions: The abundance of molecular oxygen, relative to H{2} , is 5 × 10-8 averaged over the Odin beam. This abundance is consistently lower than previously reported upper limits.Based on observations with Odin, a Swedish-led satellite project funded jointly by the Swedish National Space Board (SNSB), the Canadian Space Agency (CSA), the National Technology Agency of Finland (Tekes) and Centre National d'Étude Spatiale (CNES). The Swedish Space Corporation has been the industrial prime contractor and also is operating the satellite. Appendix A is only available in electronic form at http://www.aanda.org
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| 3. |
- Brown, Barry, et al.
(författare)
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Seeing Ethnographically: Teaching ethnography as part of CSCW
- 2007
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Ingår i: In L. J. Bannon, I. Wagner, C. Gutwin, R. H. R. Harper & K. Schmidt (Eds.), Proceedings of the 10th European Conference on Computer-Supported Cooperative Work. London: Springer. - London : Springer. ; , s. 411-430, s. 411-430
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Konferensbidrag (refereegranskat)
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| 4. |
- Brown, Barry, et al.
(författare)
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Seeing ethnographically: teaching ethnography as part of CSCW
- 2007. - 1
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Konferensbidrag (refereegranskat)abstract
- While ethnography is an established part of CSCW research, teaching and learning ethnography presents unique and distinct challenges. This paper discusses a study of fieldwork and analysis amongst a group of students learning ethnography as part of a CSCW & design course. Studying the students’ practices we explore fieldwork as a learning experience, both learning about fieldsites as well as learning the practices of ethnography. During their fieldwork and analysis the students used a wiki to collaborate, sharing their field and analytic notes. From this we draw lessons for how ethnography can be taught as a collaborative analytic process and discuss extensions to the wiki to better support its use for collaborating around fieldnotes. In closing we reflect upon the role of learning ethnography as a practical hands on – rather than theoretical – pursuit.
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| 5. |
- Larsson, Tomas, et al.
(författare)
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Early vertebrate chromosome duplications and the evolution of the neuropeptide Y receptor gene regions
- 2008
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Ingår i: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 8:1, s. 184-
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Forskningsöversikt (refereegranskat)abstract
- Background One of the many gene families that expanded in early vertebrate evolution is the neuropeptide (NPY) receptor family of G-protein coupled receptors. Earlier work by our lab suggested that several of the NPY receptor genes found in extant vertebrates resulted from two genome duplications before the origin of jawed vertebrates (gnathostomes) and one additional genome duplication in the actinopterygian lineage, based on their location on chromosomes sharing several gene families. In this study we have investigated, in five vertebrate genomes, 45 gene families with members close to the NPY receptor genes in the compact genomes of the teleost fishes Tetraodon nigroviridis and Takifugu rubripes. These correspond to Homo sapiens chromosomes 4, 5, 8 and 10. Results Chromosome regions with conserved synteny were identified and confirmed by phylogenetic analyses in H. sapiens, M. musculus, D. rerio, T. rubripes and T. nigroviridis. 26 gene families, including the NPY receptor genes, (plus 3 described recently by other labs) showed a tree topology consistent with duplications in early vertebrate evolution and in the actinopterygian lineage, thereby supporting expansion through block duplications. Eight gene families had complications that precluded analysis (such as short sequence length or variable number of repeated domains) and another eight families did not support block duplications (because the paralogs in these families seem to have originated in another time window than the proposed genome duplication events). RT-PCR carried out with several tissues in T. rubripes revealed that all five NPY receptors were expressed in the brain and subtypes Y2, Y4 and Y8 were also expressed in peripheral organs. Conclusion We conclude that the phylogenetic analyses and chromosomal locations of these gene families support duplications of large blocks of genes or even entire chromosomes. Thus, these results are consistent with two early vertebrate tetraploidizations forming a paralogon comprising human chromosomes 4, 5, 8 and 10 and one teleost tetraploidization. The combination of positional and phylogenetic data further strengthens the identification of orthologs and paralogs in the NPY receptor family.
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| 8. |
- Olinski, Robert, et al.
(författare)
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Conserved Synteny Between the Ciona Genome and Human Paralogons Identifies Large Duplication Events in the Molecular Evolution of the Insulin-Relaxin Gene Family
- 2006
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Ingår i: Molecular biology and evolution. - : Oxford University Press (OUP). - 0737-4038 .- 1537-1719. ; 23:1, s. 10-22
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Tidskriftsartikel (refereegranskat)abstract
- The aims of the study were to outline the sequence of eventsthat gave rise to the vertebrate insulin-relaxin gene familyand the chromosomal regions in which they reside. We analyzedthe gene content surrounding the human insulin/relaxin geneswith respect to what family they belonged to and if the duplicationhistory of investigated families parallels the evolution ofthe insulin-relaxin family members. Markov Clustering and phylogeneticanalysis were used to determine family identity. More than 15%of the genes belonged to families that have paralogs in theregions, defining two sets of quadruplicate paralogy-regions.Thereby, the localization of insulin/relaxin genes in humanis in accordance with that regions on human chromosomes 1, 11,12, 19q (insulin/IGFs) and 1, 6p/15q, 9/5, 19p (INSLs/relaxins)were formed during two genome duplications. We compared thehuman genome with that of Ciona intestinalis, a species thatsplit from the vertebrate lineage before the two suggested genomeduplications. Two insulin-like orthologs were discovered inaddition to the already described Ci-insulin gene. Conservedsynteny between the Ciona regions hosting the insulin-like genesand the two sets of human paralogons implies their common origin.Linkage of the two human paralogons, as seen in human chromosome1, as well as the two regions hosting the Ciona insulin-likegenes, suggests that a segmental duplication gave rise to theentire region prior to the genome doublings. Thus, preservedgene content provides support that genome duplication(s) inaddition to segmental and single gene duplications shaped thegenomes of extant vertebrates.
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