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| 2. |
- Khonsari, R H, et al.
(författare)
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Shape and volume of craniofacial cavities in intentional skull deformations
- 2013
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Ingår i: American Journal of Physical Anthropology. - : Wiley. - 0002-9483 .- 1096-8644. ; 151:1, s. 110-119
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Tidskriftsartikel (refereegranskat)abstract
- Intentional cranial deformations (ICD) have been observed worldwide but are especially prevalent in preColombian cultures. The purpose of this study was to assess the consequences of ICD on three cranial cavities (intracranial cavity, orbits, and maxillary sinuses) and on cranial vault thickness, in order to screen for morphological changes due to the external constraints exerted by the deformation device. We acquired CT-scans for 39 deformed and 19 control skulls. We studied the thickness of the skull vault using qualitative and quantitative methods. We computed the volumes of the orbits, of the maxillary sinuses, and of the intracranial cavity using haptic-aided semi-automatic segmentation. We finally defined 3D distances and angles within orbits and maxillary sinuses based on 27 anatomical landmarks and measured these features on the 58 skulls. Our results show specific bone thickness patterns in some types of ICD, with localized thinning in regions subjected to increased pressure and thickening in other regions. Our findings confirm that volumes of the cranial cavities are not affected by ICDs but that the shapes of the orbits and of the maxillary sinuses are modified in circumferential deformations. We conclude that ICDs can modify the shape of the cranial cavities and the thickness of their walls but conserve their volumes. These results provide new insights into the morphological effects associated with ICDs and call for similar investigations in subjects with deformational plagiocephalies and craniosynostoses.
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| 3. |
- Atkin, Max R., et al.
(författare)
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On the ratio probability of the smallest eigenvalues in the Laguerre unitary ensemble
- 2018
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Ingår i: Nonlinearity. - : IOP PUBLISHING LTD. - 0951-7715 .- 1361-6544. ; 31:4, s. 1155-1196
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Tidskriftsartikel (refereegranskat)abstract
- We study the probability distribution of the ratio between the second smallest and smallest eigenvalue in the n x n Laguerre unitary ensemble. The probability that this ratio is greater than r > 1 is expressed in terms of an n x n Hankel determinant with a perturbed Laguerre weight. The limiting probability distribution for the ratio as n -> infinity is found as an integral over (0, infinity) containing two functions q(1)(x) and q(2)(x). These functions satisfy a system of two coupled Painleve V equations, which are derived from a Lax pair of a Riemann-Hilbert problem. We compute asymptotic behaviours of these functions as rx -> 0(+) and (r - 1)x -> infinity, as well as large n asymptotics for the associated Hankel determinants in several regimes of r and x.
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| 4. |
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| 5. |
- Charlier, R, et al.
(författare)
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Modelling Coupled Mechanics, Moisture and Heat in Pavement Structures
- 2009
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Ingår i: Water in Road Structures. - Dordrecht : Springer. ; , s. 243-281
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Bokkapitel (refereegranskat)abstract
- Different physical problems have been analysed in the preceding {chapters}: they relate to water transfer, to heat transfer, to pollutant transfer and to mechanical equilibrium. All these problems are governed by differential equations and boundary conditions but analytical solutions are, in general, unobtainable because of the complex interaction of the various aspects which are always present in real-world situations. In such circumstances, numerical modelling can give a valuable alternative methodology for solving such highly coupled problems. The first part of this chapter is dedicated to a brief statement of the finite element method for highly coupled phenomena. In the second part, a number of numerical simulations are summarised as an illustration of what could be done with modern tools. The chapter shows that it is possible to achieve realistic results although, at present, some simplification is often required to do so.
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| 6. |
- Charlier, R, et al.
(författare)
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Water Influence on Bearing Capacity and Pavement Performance : Field Observations
- 2009
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Ingår i: Water in Road Structures. - Dordrecht : Springer. - 9781402085611 ; , s. 175-192
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Bokkapitel (refereegranskat)abstract
- This chapter presents a mechanical behaviour study, i.e. the bearing capacity as a function of the moisture degree. The field point of view is expressed and the chapter summarises a number of observations on road behaviour, in relation to variations of moisture. First, the road structure is recalled with respect to the mechanical analysis point of view. Then some observations on field under temperate climate, humid, are given. In a second step, the specific case of frost and thawing are discussed.
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| 7. |
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| 8. |
- Laloui, L., et al.
(författare)
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Water Influence on Mechanical Behaviour of Pavements : Constitutive Modelling
- 2009
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Ingår i: Water in road structures. - Dordrecht : Springer. - 9781402085611 ; , s. 193-216
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Bokkapitel (refereegranskat)abstract
- This chapter deals with the effects of water on the mechanical behaviour of pavements. The analysis is based on constitutive considerations. Constitutive models devoted to both routine and advanced pavement analysis and design are introduced and both the resilient behaviour as well as the long term elasto-plastic approaches are presented. As soon as the approach considers the material as a two phase (solid matrix and a fluid), the introduction of the effective stress concept is required. In the last section an analysis is made on the extension of the constitutive models to the characterisation of partially saturated materials
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| 9. |
- Naveau, Elise, et al.
(författare)
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Alteration of rat fetal cerebral cortex development after prenatal exposure to polychlorinated biphenyls
- 2014
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Ingår i: PLOS ONE. - : PLOS. - 1932-6203. ; 9:3
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Tidskriftsartikel (refereegranskat)abstract
- Polychlorinated biphenyls (PCBs) are environmental contaminants that persist in environment and human tissues. Perinatal exposure to these endocrine disruptors causes cognitive deficits and learning disabilities in children. These effects may involve their ability to interfere with thyroid hormone (TH) action. We tested the hypothesis that developmental exposure to PCBs can concomitantly alter TH levels and TH-regulated events during cerebral cortex development: progenitor proliferation, cell cycle exit and neuron migration. Pregnant rats exposed to the commercial PCB mixture Aroclor 1254 ended gestation with reduced total and free serum thyroxine levels. Exposure to Aroclor 1254 increased cell cycle exit of the neuronal progenitors and delayed radial neuronal migration in the fetal cortex. Progenitor cell proliferation, cell death and differentiation rate were not altered by prenatal exposure to PCBs. Given that PCBs remain ubiquitous, though diminishing, contaminants in human systems, it is important that we further understand their deleterious effects in the brain.
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