1. |
- Costa, Luciano da F, et al.
(författare)
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Analyzing and modeling real-world phenomena with complex networks: a survey of applications
- 2011
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Ingår i: Advances in Physics. - : Informa UK Limited. - 0001-8732 .- 1460-6976. ; 60:3, s. 329-412
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Forskningsöversikt (refereegranskat)abstract
- The success of new scientific areas can be assessed by their potential in contributing to new theoretical approaches and in applications to real-world problems. Complex networks have fared extremely well in both of these aspects, with their sound theoretical basis being developed over the years and with a variety of applications. In this survey, we analyze the applications of complex networks to real-world problems and data, with emphasis in representation, analysis and modeling. A diversity of phenomena are surveyed, which may be classified into no less than 11 areas, providing a clear indication of the impact of the field of complex networks.
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3. |
- Gustafsson, Kristian, 1980, et al.
(författare)
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Statistical models for spatial patterns of heavy particles in turbulence
- 2016
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Ingår i: Advances in Physics. - : Informa UK Limited. - 0001-8732 .- 1460-6976. ; 65:1, s. 1-57
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Forskningsöversikt (refereegranskat)abstract
- The dynamics of heavy particles suspended in turbulent flows is of fundamental importance for a wide range of questions in astrophysics, atmospheric physics, oceanography, and technology. Laboratory experiments and numerical simulations have demonstrated that heavy particles respond in intricate ways to turbulent fluctuations of the carrying fluid: non-interacting particles may cluster together and form spatial patterns even though the fluid is incompressible, and the relative speeds of nearby particles can fluctuate strongly. Both phenomena depend sensitively on the parameters of the system. This parameter dependence is difficult to model from first principles since turbulence plays an essential role. Laboratory experiments are also very difficult, precisely since they must refer to a turbulent environment. But in recent years it has become clear that important aspects of the dynamics of heavy particles in turbulence can be understood in terms of statistical models where the turbulent fluctuations are approximated by Gaussian random functions with appropriate correlation functions. In this review we summarise how such statistical-model calculations have led to a detailed understanding of the factors that determine heavy-particle dynamics in turbulence. We concentrate on spatial clustering of heavy particles in turbulence. This is an important question because spatial clustering affects the collision rate between the particles and thus the long-term fate of the system.
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4. |
- Häggkvist, Roland, et al.
(författare)
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On the Ising model for the simple cubic lattice
- 2007
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Ingår i: Advances in Physics. - : Informa UK Limited. - 0001-8732 .- 1460-6976. ; 56:5, s. 653-755
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Forskningsöversikt (refereegranskat)abstract
- The Ising model was introduced in 1920 to describe a uniaxial system of magnetic moments, localized on a lattice, interacting via nearest-neighbour exchange interaction. It is the generic model for a continuous phase transition and arguably the most studied model in theoretical physics. Since it was solved for a two-dimensional lattice by Onsager in 1944, thereby representing one of the very few exactly solvable models in dimensions higher than one, it has served as a testing ground for new developments in analytic treatment and numerical algorithms. Only series expansions and numerical approaches, such as Monte Carlo simulations, are available in three dimensions. This review focuses on Monte Carlo simulation. We build upon a data set of unprecedented size. A great number of quantities of the model are estimated near the critical coupling. We present both a conventional analysis and an analysis in terms of a Puiseux series for the critical exponents. The former gives distinct values of the high- and low-temperature exponents; by means of the latter we can get these exponents to be equal at the cost of having true asymptotic behaviour being found only extremely close to the critical point. The consequences of this for simulations of lattice systems are discussed at length.
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5. |
- Sundqvist, Bertil
(författare)
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Fullerenes under high pressures
- 1999
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Ingår i: Advances in Physics. - : Informa UK Limited. - 0001-8732 .- 1460-6976. ; 48:1, s. 1-134
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Forskningsöversikt (övrigt vetenskapligt/konstnärligt)abstract
- This paper reviews the properties and phases of fullerenes and their derivatives and compounds under high pressures. For obvious reasons most of the paper deals with C60 but the materials reviewed also include C70, simple derivatives of C60, carbon nanotubes, and intercalation compounds of C60 with both acceptors and donors, mainly alkali metals. After a brief overview of high-pressure techniques and the structures and properties of C60 at atmospheric pressure, the structural phase diagram of C60 from atmospheric pressure to above 40GPa (400kbar) is reviewed. The evolution with pressure of the orientational and translational structure of 'normal' molecular C60 in the range up to 1-5GPa (depending on temperature) is discussed in some detail, as is the appearance of a large number of polymeric phases at higher pressures and temperatures, some of them known to have extreme mechanical properties. At very high static (or shock) pressures or temperatures, C60 transforms into ordered or disordered forms of diamond or graphite. The phase diagram is reasonably well investigated up to near 10GPa, but at higher pressures there are still large gaps in our knowledge. Available experimental data for the physical properties of both monomeric and polymeric C60 under high pressures are reviewed as far as possible. The compression behaviour of C60 has been well investigated and is discussed in detail because of its basic importance, but optical, electrical and lattice properties have also been studied for several of the many structural phases of C60. Whenever possible, experimental data are compared with the results of theoretical calculations. The phase diagram and properties of C70 are much less known because of the larger complexity caused by the anisotropy of the molecule, and very little is known about most compounds of C60. However, noble-gas intercalation in C60 has been reasonably well investigated. Finally, the high-pressure properties of superconducting alkali-metalintercalated C60 are briefly reviewed.
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6. |
- Wehling, T. O., et al.
(författare)
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Dirac materials
- 2014
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Ingår i: Advances in Physics. - : Informa UK Limited. - 0001-8732 .- 1460-6976. ; 63:1, s. 1-76
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Forskningsöversikt (refereegranskat)abstract
- A wide range of materials, like d-wave superconductors, graphene, and topological insulators, share a fundamental similarity: their low-energy fermionic excitations behave as massless Dirac particles rather than fermions obeying the usual Schrodinger Hamiltonian. This emergent behavior of Dirac fermions in condensed matter systems defines the unifying framework for a class of materials we call Dirac materials. In order to establish this class of materials, we illustrate how Dirac fermions emerge in multiple entirely different condensed matter systems and we discuss how Dirac fermions have been identified experimentally using electron spectroscopy techniques (angle-resolved photoemission spectroscopy and scanning tunneling spectroscopy). As a consequence of their common low-energy excitations, this diverse set of materials shares a significant number of universal properties in the low-energy (infrared) limit. We review these common properties including nodal points in the excitation spectrum, density of states, specific heat, transport, thermodynamic properties, impurity resonances, and magnetic field responses, as well as discuss many-body interaction effects. We further review how the emergence of Dirac excitations is controlled by specific symmetries of the material, such as time-reversal, gauge, and spin-orbit symmetries, and how by breaking these symmetries a finite Dirac mass is generated. We give examples of how the interaction of Dirac fermions with their distinct real material background leads to rich novel physics with common fingerprints such as the suppression of back scattering and impurity-induced resonant states.
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7. |
- Cederberg, David, et al.
(författare)
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Extreme intracranial pressure elevation > 90 mmHg in an awake patient with primary CNS lymphoma—case report
- 2020
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Ingår i: Acta Neurochirurgica. - : Springer Science and Business Media LLC. - 0001-6268 .- 0942-0940. ; 162:8, s. 1819-1823
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Tidskriftsartikel (refereegranskat)abstract
- We describe a patient with primary CNS lymphomas, awake despite an extreme ICP elevation. A 48-year-old woman presented with headache since 1 month, and bilateral papillary edema was observed. Magnetic resonance imaging revealed diffuse infiltration around the petrous bone. Following external ventricular drainage (EVD) placement, ICP levels of > 90 mmHg were recorded while the patient was fully awake. Cytology revealed an aggressive primary CNS lymphoma. Cerebrospinal fluid (CSF) drainage at high opening pressure levels was required. We conclude that extreme ICP elevations, treatable by CSF drainage, can be observed without a reduced level of consciousness.
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8. |
- Tegner, Eva, et al.
(författare)
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Erythroderma with sparing around the nipples
- 2003
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Ingår i: Acta Dermato-Venereologica. - : Medical Journals Sweden AB. - 1651-2057 .- 0001-5555. ; 83:3, s. 236-236
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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