| 1. |
- Clark, Andrew G., et al.
(författare)
-
Evolution of genes and genomes on the Drosophila phylogeny
- 2007
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 450:7167, s. 203-218
-
Tidskriftsartikel (refereegranskat)abstract
- Comparative analysis of multiple genomes in a phylogenetic framework dramatically improves the precision and sensitivity of evolutionary inference, producing more robust results than single-genome analyses can provide. The genomes of 12 Drosophila species, ten of which are presented here for the first time (sechellia, simulans, yakuba, erecta, ananassae, persimilis, willistoni, mojavensis, virilis and grimshawi), illustrate how rates and patterns of sequence divergence across taxa can illuminate evolutionary processes on a genomic scale. These genome sequences augment the formidable genetic tools that have made Drosophila melanogaster a pre-eminent model for animal genetics, and will further catalyse fundamental research on mechanisms of development, cell biology, genetics, disease, neurobiology, behaviour, physiology and evolution. Despite remarkable similarities among these Drosophila species, we identified many putatively non-neutral changes in protein-coding genes, non-coding RNA genes, and cis-regulatory regions. These may prove to underlie differences in the ecology and behaviour of these diverse species.
|
|
| 2. |
|
|
| 3. |
- Beisert, Niklas, et al.
(författare)
-
Review of AdS/CFT Integrability : An Overview
- 2012
-
Ingår i: Letters in Mathematical Physics. - : Springer Science and Business Media LLC. - 0377-9017 .- 1573-0530. ; 99:1-3, s. 3-32
-
Forskningsöversikt (refereegranskat)abstract
- This is the introductory chapter of a review collection on integrability in the context of the AdS/CFT correspondence. In the collection we present an overview of the achievements and the status of this subject as of the year 2010.
|
|
| 4. |
- Chiodaroli, Marco, et al.
(författare)
-
“Every morning I take two steps to my desk…” : students’ perspectives on distance learning during the COVID-19 pandemic
- 2024
-
Ingår i: Higher Education. - : Springer Science+Business Media B.V.. - 0018-1560 .- 1573-174X.
-
Tidskriftsartikel (refereegranskat)abstract
- During the COVID-19 pandemic, distance learning became the predominant teaching method at most universities, exposing students and teachers alike to novel and unexpected challenges and learning opportunities. Our study is situated in the context of higher physics education at a large Swedish university and adopts a mixed-methods approach to explore how students perceive shifts to distance learning. Quantitative student survey responses comparing distance learning during the pandemic with previous in-person learning are analyzed with k-means cluster analysis and with a random-intercept multilevel linear model. Combined analyses produce a consistent picture of students who report having experienced the greatest challenges. They are on average younger, report being less autonomous in their learning, and find it harder than peers to ask questions to the instructor. They are also less likely to have access to a place where they can study without interruptions. Variation across courses is small with students being largely subjected to the same set of challenges. Qualitative data from semi-structured focus group interviews and open-ended questions supports these findings, provides a deeper understanding of the struggles, and reveals possibilities for future interventions. Students report an overall collapse of structure in their learning that takes place along multiple dimensions. Our findings highlight a fundamental role played by informal peer-to-peer and student-instructor interactions, and by the exchange of what we refer to as “structural information.” We discuss implications for teachers and institutions regarding the possibility of providing support structures, such as study spaces, as well as fostering student autonomy.
|
|
| 5. |
- Faddeev, Ludwig D., et al.
(författare)
-
Shafranov's virial theorem and magnetic plasma confinement
- 2002
-
Ingår i: Journal of Physics A. - : IOP Publishing. - 0305-4470 .- 1361-6447. ; 35:11, s. L133-L139
-
Tidskriftsartikel (refereegranskat)abstract
- Shafranov's virial theorem implies that nontrivial magnetohydrodynamical equilibrium configurations must be supported by externally supplied currents. Here we extend the virial theorem to field theory, where it relates to Derrick's scaling argument on soliton stability. We then employ virial arguments to investigate a realistic field theory model of a two-component plasma, and conclude that stable localized solitons can exist in the bulk of a finite density plasma. These solitons entail a nontrivial electric field, which implies that purely magnetohydrodynamical arguments are insufficient for describing stable, nontrivial structures within the bulk of a plasma.
|
|
| 6. |
- Freyhult, Lisa, et al.
(författare)
-
A generalized scaling function for AdS/CFT
- 2008
-
Ingår i: Journal of Statistical Mechanics. - 1742-5468. ; , s. P07015-
-
Tidskriftsartikel (refereegranskat)abstract
- We study a refined large spin limit for twist operators in the sl(2) sector of AdS/CFT. We derive a novel non-perturbative equation for the generalized two-parameter scaling function associated with this limit, and analyze it for weak coupling. It is expected to smoothly interpolate between weakly coupled gauge theory and string theory for strong coupling.
|
|
| 7. |
|
|
| 8. |
- Freyhult, Lisa, 1977-
(författare)
-
Aspects of Yang-Mills Theory : Solitons, Dualities and Spin Chains
- 2004
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- One of the still big problems in the Standard Model of particle physics is the problem of confinement. Quarks or other coloured particles have never been observed in isolation. Quarks are only observed in colour neutral bound states. The strong interactions are described using a Yang-Mills theory. These type of theories exhibits asymptotic freedom, i.e. the coupling is weak at high energies. This means that the theory is perturbative at high energies only. Understanding quark confinement requires knowledge of the non perturbative regime. One attempt has been to identify the proper order parameters for describing the low energy limit and then to write down effective actions in terms of these order parameters. We discuss one possible scenario for confinement and the effective models constructed with this as inspiration. Further we discuss solitons in these models and their properties.Yang-Mills theory has also become important in the context of string theory. According to the AdS/CFT correspondence string theory in AdS5×S5 is dual to four dimensional Yang-Mills with four supersymmetries. The duality relate the non perturbative regime of one of the theories to the perturbative regime of the other. This makes it in general hard to test this conjecture. For a special type of solutions it is however possible to use a perturbative expansion in both theories. We discuss this type of solutions and in particular we discuss a method, the Bethe ansatz, to find the solutions on the gauge theory side.
|
|
| 9. |
|
|
| 10. |
- Freyhult, Lisa
(författare)
-
Bethe ansatz and fluctuations in SU(3) Yang-Mills operators
- 2004
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Science and Business Media LLC. - 1126-6708 .- 1029-8479. ; :06, s. 010-
-
Tidskriftsartikel (refereegranskat)abstract
- We consider the scalar operators corresponding to semiclassical string states in AdS5 × S5 with the three angular momenta in S5 non-trivial. The string states recieve quantum corrections and we study the corresponding process on the gauge theory side. The anomalous dimension of the scalar operators is computed using the Bethe ansatz and we find the correction that corresponds to the energy of the quantized string. We restrict for simplicity to the case where two of the angular momenta in S5 are equal.
|
|
