| 1. |
- Cederwall, Bo, et al.
(författare)
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Evidence for a spin-aligned neutron-proton paired phase from the level structure of 92Pd
- 2011
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 469:7328, s. 68-71
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Tidskriftsartikel (refereegranskat)abstract
- Shell structure and magic numbers in atomic nuclei were generally explained by pioneering work(1) that introduced a strong spin-orbit interaction to the nuclear shell model potential. However, knowledge of nuclear forces and the mechanisms governing the structure of nuclei, in particular far from stability, is still incomplete. In nuclei with equal neutron and proton numbers (N = Z), enhanced correlations arise between neutrons and protons (two distinct types of fermions) that occupy orbitals with the same quantum numbers. Such correlations have been predicted to favour an unusual type of nuclear superfluidity, termed isoscalar neutron-proton pairing(2-6), in addition to normal isovector pairing. Despite many experimental efforts, these predictions have not been confirmed. Here we report the experimental observation of excited states in the N = Z = 46 nucleus Pd-92. Gamma rays emitted following the Ni-58(Ar-36,2n)Pd-92 fusion-evaporation reaction were identified using a combination of state-of-the-art high-resolution c-ray, charged-particle and neutron detector systems. Our results reveal evidence for a spin-aligned, isoscalar neutron-proton coupling scheme, different from the previous prediction(2-6). We suggest that this coupling scheme replaces normal superfluidity (characterized by seniority coupling(7,8)) in the ground and low-lying excited states of the heaviest N = Z nuclei. Such strong, isoscalar neutron-proton correlations would have a considerable impact on the nuclear level structure and possibly influence the dynamics of rapid proton capture in stellar nucleosynthesis.
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| 2. |
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| 3. |
- Eriksson, Johan, et al.
(författare)
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Changing Zaire to Congo : The fate of no-longer relevant mnemonic information.
- 2014
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 101, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- In an ever-changing world there is constant pressure on revising long-term memory, such when people or countries change name. What happens to the old, pre-existing information? One possibility is that old associations gradually are weakened and eventually lost. Alternatively, old and no longer relevant information may still be an integral part of memory traces. To test the hypothesis that old mnemonic information still becomes activated when people correctly retrieve new, currently relevant information, brain activity was measured with fMRI while participants performed a cued-retrieval task. Paired associates (symbol-sound and symbol-face pairs) were first learned during two days. Half of the associations were then updated during the next two days, followed by fMRI scanning on day 5 and also 18months later. As expected, retrieval reactivated sensory cortex related to the most recently learned association (visual cortex for symbol-face pairs, auditory cortex for symbol-sound pairs). Critically, retrieval also reactivated sensory cortex related to the no-longer relevant associate. Eighteen months later, only non-updated symbol-face associations were intact. Intriguingly, a subset of the updated associations was now treated as though the original association had taken over, in that memory performance was significantly worse than chance and that activity in sensory cortex for the original but not the updated associate correlated (negatively) with performance. Moreover, the degree of "residual" reactivation during day 5 inversely predicted memory performance 18months later. Thus, updating of long-term memory involves adding new information to already existing networks, in which old information can stay resilient for a long time.
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| 4. |
- Ghazi Moradi, Farnaz, et al.
(författare)
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High-spin study of 162Ta
- 2011
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 84:6, s. 064312-
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Tidskriftsartikel (refereegranskat)abstract
- Excited states in the odd-odd neutron deficient nucleus (162)Ta (Z = 73, N = 89) have been studied for the first time. The gamma spectroscopy analysis using gamma - gamma - gamma coincidences revealed a strongly coupled rotational structure that was established up to large angular momentum states. The rotational band was assigned to the configuration pi h(11/2)[514]9/2 circle times nu i(13/2)[660]1/2 based on its rotational and electromagnetic properties. The data are interpreted within the framework of total Routhian surface calculations, which suggests an axially symmetric shape with a gamma-softminimum at beta(2) approximate to 0.16 and gamma approximate to 6 degrees. The crossing of the signature partners observed in heavier (N >= 91) odd-odd nuclides in this mass region is found to be absent at N = 89. This might be correlated with a change in S-band structure above the paired band crossing at these neutron numbers.
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| 5. |
- Mårtensson, Johan, et al.
(författare)
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Growth of language-related brain areas after foreign language learning
- 2012
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 63:1, s. 240-244
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Tidskriftsartikel (refereegranskat)abstract
- The influence of adult foreign-language acquisition on human brain organization is poorly understood. We studied cortical thickness and hippocampal volumes of conscript interpreters before and after three months of intense language studies. Results revealed increases in hippocampus volume and in cortical thickness of the left middle frontal gyrus, inferior frontal gyrus, and superior temporal gyrus for interpreters relative to controls. The right hippocampus and the left superior temporal gyrus were structurally more malleable in interpreters acquiring higher proficiency in the foreign language. Interpreters struggling relatively more to master the language displayed larger gray matter increases in the middle frontal gyrus. These findings confirm structural changes in brain regions known to serve language functions during foreign-language acquisition.
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| 6. |
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| 7. |
- Nyberg, Annakarin, 1975-, et al.
(författare)
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Sociala medier och härskartekniker
- 2014. - 1
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- En snabb kommentar, en gest eller bara en lite för lång konstpaus kan fullständigt omdefiniera det sociala rummet. Mellan två personer skapas en maktasymmetri där den ena parten använder tekniker för att ställa sig ovanför, vid sidan om, eller i avstånd från den andre. Det sker subtilt men ändå så uppenbart. Det handlar om härskartekniker.Sociala medier är inget undantag. Även på Twitter, Facebook, Instagram och i exempelvis bloggosfären, pågår liknande sociala makt- och positioneringsspel. I den här boken möter du nätprofilerna Johanna Frändén och Clara Lidström som båda har skapat sig en stark röst och position i de sociala medierna. Genom deras erfarenheter lär vi oss om strategier som har vuxit fram för att förhålla sig till det sociala spel som pågår på nätet.Bokens teoretiska utgångspunkt är de handlingsutrymmen och härskartekniker som de sociala medierna möjliggör. Författarna Annakarin Nyberg och Mikael Wiberg presenterar tio härskartekniker som idag utövas på nätet – och tio motstrategier för att utveckla ett bättre förhållningssätt till såväl subtila som tydliga härskartekniker i sociala medier.Sociala medier och härskartekniker vänder sig till dig som vill förstå vår digitala samtid. Boken syftar till att medvetandegöra det komplexa i det till synes ytliga i vår vardag på nätet.
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| 8. |
- Nyberg, Lars, et al.
(författare)
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Longitudinal evidence for diminished frontal-cortex function in aging
- 2010
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 107:52, s. 22682-22686
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Tidskriftsartikel (refereegranskat)abstract
- Cross-sectional estimates of age-related changes in brain structure and function were compared with 6-y longitudinal estimates. The results indicated increased sensitivity of the longitudinal approach as well as qualitative differences. Critically, the cross-sectional analyses were suggestive of age-related frontal overrecruitment, whereas the longitudinal analyses revealed frontal underrecruitment with advancing age. The cross-sectional observation of overrecruitment reflected a select elderly sample. However, when followed over time, this sample showed reduced frontal recruitment. These findings dispute inferences of true age changes on the basis of age differences, hence challenging some contemporary models of neurocognitive aging, and demonstrate age-related decline in frontal brain volume as well as functional response.
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| 9. |
- Quennerstedt, Mikael, et al.
(författare)
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Learning and active video gaming in school
- 2014
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Konferensbidrag (refereegranskat)abstract
- Video- and computer games are an important part of youth culture, criticised in terms of sedentary lifestyles as well as held forth as an important competence for the future in terms of IT-competence. A certain type of videogames, so called exergames, is now put forward as interesting tools in schools since they combine IT-technology and physical activity. In this symposium we will present results from a four-year study with the aim to investigate the learning regarding the body, physical activity and health that take place in young peoples playing of exergames. The project has first investigated if teachers use videogames in health- and physical education as well as explored the arguments for doing that. Secondly, the content offered in the games regarding the body, physical activity and health has been explored in game manuals and in the game-play content. Thirdly, and in focus for this symposium, the project has explored what young people learn playing videogames and how this learning occurs. The study has been carried out through video- and audio recordings of on-going video gaming both during physical education lessons in Sweden, and when small groups of youth have played the games once a week during ten weeks. The analysis have focused on spoken as well as embodied actions appearing in young peoples playing of different exergames. In the symposium results will be presented and discussed in relation to (i) How images of health and the human body is taught by using exergames in school, (ii) Young people’s aesthetic experiences of playing exergames, (iii) How exergames are used to teach dance in PE, and (iv) How Laban Movement Analysis can be used to understand the learning of movement qualities in game-play.
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| 10. |
- Sjöberg, Jonny, et al.
(författare)
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Computer simulations of blasting with precise initiation
- 2012
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Konferensbidrag (refereegranskat)abstract
- Using blasting caps with electronic delay units, it has become possible to employ wave superposition in rock blasting. This paper presents computer simulations to investigate the hypothesis that fragmentation is improved in areas between blast holes where the tensile waves meet, overlap and interact. In this study, a numerical methodology using the code LS-DYNA was developed. LS-DYNA is a commercially available multi-purpose finite-element code, which is well suited to various types of dynamic modeling. Two different element formulations were used — Euler formulation in, and close to, the blast hole, and Lagrange formulation in the rock volume farther from the blast hole. The models used have a resolution (element size) of 50 mm and comprise approximately 20 million elements. Single and dual blast hole configurations have been studied, and a methodology to calculate possible fragmentation based on model interpretation was developed. The results showed that the amount of explosives and the blast hole spacing had the largest effect on fragmentation. The effect of varying delay times was small and local, implying that a significant increase in fragmentation should not be expected through wave superposition.
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