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| 2. |
- Chapman, Henry N, et al.
(författare)
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Femtosecond X-ray protein nanocrystallography.
- 2011
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 470:7332, s. 73-7
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Tidskriftsartikel (refereegranskat)abstract
- X-ray crystallography provides the vast majority of macromolecular structures, but the success of the method relies on growing crystals of sufficient size. In conventional measurements, the necessary increase in X-ray dose to record data from crystals that are too small leads to extensive damage before a diffraction signal can be recorded. It is particularly challenging to obtain large, well-diffracting crystals of membrane proteins, for which fewer than 300 unique structures have been determined despite their importance in all living cells. Here we present a method for structure determination where single-crystal X-ray diffraction 'snapshots' are collected from a fully hydrated stream of nanocrystals using femtosecond pulses from a hard-X-ray free-electron laser, the Linac Coherent Light Source. We prove this concept with nanocrystals of photosystem I, one of the largest membrane protein complexes. More than 3,000,000 diffraction patterns were collected in this study, and a three-dimensional data set was assembled from individual photosystem I nanocrystals (∼200nm to 2μm in size). We mitigate the problem of radiation damage in crystallography by using pulses briefer than the timescale of most damage processes. This offers a new approach to structure determination of macromolecules that do not yield crystals of sufficient size for studies using conventional radiation sources or are particularly sensitive to radiation damage.
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| 3. |
- Dinasquet, Julie, et al.
(författare)
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Cascading effects of the ctenophore Mnemiopsis leidyi on the planktonic food web in a nutrient-limited estuarine system
- 2012
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Ingår i: Marine Ecology Progress Serie. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 460, s. 49-61
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Tidskriftsartikel (refereegranskat)abstract
- Increasing biomasses of gelatinous zooplankton presumably have major implications for the structure and function of marine food webs at large; however, current data on lower trophic levels are scarce, as most studies have focused on the immediate effects on zooplankton and fish larvae only. We examined the short-term impact of larvae and adults of the invasive ctenophore Mnemiopsis leidyi on a summer planktonic food web in the estuarine southern Baltic Sea, with special emphasis on the microbial loop. Grazing by M. leidyi reduced the mesozooplankton biomass, followed by increased dinoflagellate biomass in treatments with M. leidyi. While chlorophyll a increased most in the treatments with M. leidyi, small phytoplankton and ciliates decreased in all treatments. M. leidyi had a slight effect on bacterial abundance, but not on bacterial production, ectoenzymatic activities, or community composition. Undetectable levels of phosphate and a gradual accumulation of dissolved organic carbon during the experiment suggested a malfunctioning microbial loop scenario. The experiment shows that direct and indirect short-term effects of M. leidyi on the estuarine food web are limited to higher trophic levels and indicates that top-down and bottom-up consequences of M. leidyi expansions on the microbial loop will likely depend on local nutrient conditions.
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| 4. |
- Peter, Christian, et al.
(författare)
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AGNES : connecting people in a multimodal way
- 2013
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Ingår i: Journal on Multimodal User Interfaces. - : Springer Berlin/Heidelberg. - 1783-7677 .- 1783-8738. ; 7:3, s. 229-245
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Tidskriftsartikel (refereegranskat)abstract
- Western societies are confronted with a number of challenges caused by the increasing number of older citizens. One important aspect is the need and wish of older people to live as long as possible in their own home and maintain an independent life. As people grew older, their social networks disperse, with friends and families moving to other parts of town, other cities or even countries. Additionally, people become less mobile with age, leading to less active participation in societal life. Combined, this normal, age-related development leads to increased loneliness and social isolation of older people, with negative effects on mental and physical health of those people. In the AGNES project, a home-based system has been developed that allows connecting elderly with their families, friends and other significant people over the Internet. As most older people have limited experience with computers and often special requirements on technology, one focus of AGNES was to develop with the users novel technological means for interacting with their social network. The resulting system uses ambient displays, tangible interfaces and wearable devices providing ubiquitous options for interaction with the network, and secondary sensors for additionally generating carefully chosen information on the person to be relayed to significant persons. Evaluations show that the chosen modalities for interaction are well adopted by the users. Further it was found that use of the AGNES system had positive effects on the mental state of the users, compared to the control group without the technology.
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| 5. |
- Peter, Christian, et al.
(författare)
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The AGNES System for Ambient Social Interaction
- 2012
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Ingår i: Proceedings of the 5th International Conference on PErvasive Technologies Related to Assistive Environments. - New York, NY, USA : ACM Digital Library. - 9781450313001
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Konferensbidrag (refereegranskat)abstract
- This paper describes the AGNES system, a technology for connecting people at home with their social network be means of off-the-shelf sensing devices and an Internet-based social network. The system provides the user with relevant information of the network by use of traditional information and communication technology as well as dedicated ambient and tangible devices. We describe briefly the requirements on such technology that were elaborated in the frame of the AGNES project, and give an overview of the system developed.
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| 6. |
- Sjögren, Karl-Göran, 1949, et al.
(författare)
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Kinship and social organization in Copper Age Europe. A cross-disciplinary analysis of archaeology, DNA, isotopes, and anthropology from two Bell Beaker cemeteries.
- 2020
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 15:11
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Tidskriftsartikel (refereegranskat)abstract
- We present a high-resolution cross-disciplinary analysis of kinship structure and social institutions in two Late Copper Age Bell Beaker culture cemeteries of South Germany containing 24 and 18 burials, of which 34 provided genetic information. By combining archaeological, anthropological, genetic and isotopic evidence we are able to document the internal kinship and residency structure of the cemeteries and the socially organizing principles of these local communities. The buried individuals represent four to six generations of two family groups, one nuclear family at the Alburg cemetery, and one seemingly more extended at Irlbach. While likely monogamous, they practiced exogamy, as six out of eight non-locals are women. Maternal genetic diversity is high with 23 different mitochondrial haplotypes from 34 individuals, whereas all males belong to one single Y-chromosome haplogroup without any detectable contribution from Y-chromosomes typical of the farmers who had been the sole inhabitants of the region hundreds of years before. This provides evidence for the society being patrilocal, perhaps as a way of protecting property among the male line, while in-marriage from many different places secured social and political networks and prevented inbreeding. We also find evidence that the communities practiced selection for which of their children (aged 0-14 years) received a proper burial, as buried juveniles were in all but one case boys, suggesting the priority of young males in the cemeteries. This is plausibly linked to the exchange of foster children as part of an expansionist kinship system which is well attested from later Indo-European-speaking cultural groups.
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