| 1. |
- Coslovich, Francesco, 1990, et al.
(author)
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Added resistance, heave and pitch for the KVLCC2 tanker using a fully nonlinear unsteady potential flow boundary element method
- 2021
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In: Ocean Engineering. - : Elsevier Ltd. - 0029-8018 .- 1873-5258. ; 229
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Journal article (peer-reviewed)abstract
- In this paper, a fully nonlinear unsteady potential flow method is used to predict added resistance, heave and pitch for the KVLCC2 hull in regular head waves at design speed. The method presents a nonlinear decomposition of the velocity potential and the wave field and an adaptive grid refinement. A formulation for the acceleration potential is used to obtain the pressure. To improve computational efficiency, a Barnes-Hut algorithm is introduced. A grid dependency study and a study on the impact of different time steps on the solution are performed. Numerical results have been compared with experimental data for the design speed. A general good agreement is found for added resistance, especially for longer waves. Heave and pitch are properly computed for all wave lengths in the range λ/Lpp=0.4 to 1.4. © 2021 The Author(s)
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| 2. |
- Jalkanen, Jukka-Pekka, et al.
(author)
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Modeling of ships as a source of underwater noise
- 2017
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Conference paper (other academic/artistic)abstract
- Shipping as a source of underwater noise is increasing. Underwater noise emission levels are seldom considered as a ship design parameter unless low vessel noise is specifically required, like in the case of warships and research vessels. Noise emissions are not regulated yet, but the awareness of possible impacts of noise on marine life is increasing. This paper describes the implementation of a noise source model for the Ship Traffic Emission Abatement Model (STEAM; Jalkanen et al. 2009; 2012; Johansson et al, 2017). The combination of vessel technical description and activity can be used to generate noise source maps which are based on actual ship traffic data. The generated noise source maps can ve used to describe the energy emitted as noise to the water, which facilitates regular annual updates of the noise emissions from ship traffic in the Baltic Sea area.
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| 3. |
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| 4. |
- Lindberg, Eskil, 1979-, et al.
(author)
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A vibro-acoustic reduced order model using undeformed coupling interface substructuring - Application to rubber bushing isolation in vehicle suspension systems
- 2014
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In: Applied Acoustics. - : Elsevier BV. - 0003-682X .- 1872-910X. ; 78, s. 43-50
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Journal article (peer-reviewed)abstract
- A vibro-acoustic reduced order model (ROM) based on a substructuring method using undeformed coupling interfaces (UCI) is proposed. The method may be used to reduce the order of a global problem, this by subdividing the global system to substructures interacting through UCI's. The local dynamic stiffness of each substructure may then be modelled with a, for that particular problem, best suited description. The feasibility of the method is demonstrated by a sensitivity analysis of the vibro-acoustic power isolation in a vehicle suspension system, comprising of a link arm connected to a vehicle car body through two rubber bushings. The link arm ROM is a component mode synthesis (CMS)-UCI, the rubber bushing model is a UCI-ROM derived from a 2D axisymmetric model using a frequency dependent visco-elastic material model. Finally the car body model is a frequency dependent UCI-ROM from a full car body finite element model. It is shown that the UCI-ROM approach efficiently can be used for parametric studies on a substructure level. The results suggest that the performed reorientation of the rubber bushings can alter, with orders of magnitude, the energy flow into the car.
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| 5. |
- Lindberg, Olof, et al.
(author)
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Hippocampal Shape Analysis in Alzheimer's Disease and Frontotemporal Lobar Degeneration Subtypes
- 2012
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In: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 30:2, s. 355-365
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Journal article (peer-reviewed)abstract
- Hippocampal pathology is central to Alzheimer's disease (AD) and other forms of dementia such as frontotemporal lobar degeneration (FTLD). Autopsy studies have shown that certain hippocampal subfields are more vulnerable than others to AD and FTLD pathology, in particular the subiculum and cornu ammonis 1 (CA1). We conducted shape analysis of hippocampi segmented from structural T1 MRI images on clinically diagnosed dementia patients and controls. The subjects included 19 AD and 35 FTLD patients [13 frontotemporal dementia (FTD), 13 semantic dementia (SD), and 9 progressive nonfluent aphasia (PNFA)] and 21 controls. Compared to controls, SD displayed severe atrophy of the whole left hippocampus. PNFA and FTD also displayed atrophy on the left side, restricted to the hippocampal head in FTD. Finally, AD displayed most atrophy in left hippocampal body with relative sparing of the hippocampal head. Consistent with neuropathological studies, most atrophic deformation was found in CA1 and subiculum areas in FTLD and AD.
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| 6. |
- Looi, Jefferey Chee Leong, et al.
(author)
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Shape analysis of the neostriatum in frontotemporal lobar degeneration, Alzheimer's disease, and controls
- 2010
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In: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 51:3, s. 970-986
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Journal article (peer-reviewed)abstract
- Background and purpose: Frontostriatal circuit mediated cognitive dysfunction has been implicated in frontotemporal lobar degeneration (FTLD), but not Alzheimer's disease, or healthy aging. We measured the neostriatum (caudate nucleus and putamen) volume in FTLD (n=34), in comparison with controls (n=27) and Alzheimer's disease (AD, n=19) subjects. Methods: Diagnoses were based on international consensus criteria. Manual bilateral segmentation of the caudate nucleus and putamen was conducted blind to diagnosis by a single analyst, on MRI scans using a standardized protocol. Intra-cranial volume was calculated via a stereological point counting technique and was used for scaling the shape analysis. The manual segmentation binaries were analyzed using UNC Shape Analysis tools (University of North Carolina) to perform comparisons among FTLD, AD, and controls for global shape, local p-value significance maps, and mean magnitude of shape displacement. Results: Shape analysis revealed that there was significant shape difference between FTLD, AD, and controls, consistent with the predicted frontostriatal dysfunction and of significant magnitude, as measured by displacement maps. There was a lateralized difference in shape for the left caudate for FTLD compared to AD; non-specific global atrophy in AD compared to controls; while FTLD showed a more specific pattern in regions relaying fronto- and corticostriatal circuits. Conclusions: Shape analysis shows regional specificity of atrophy, manifest as shape deflation, with implications for frontostriatal and corticostriatal motoric circuits, in FTLD, AD, and controls.
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| 7. |
- Looi, Jeffrey Chee Leong, et al.
(author)
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Shape analysis of the neostriatum in subtypes of frontotemporal lobar degeneration : neuroanatomically significant regional morphologic change
- 2011
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In: Psychiatry Research. - : Elsevier BV. - 0925-4927 .- 1872-7506 .- 0165-1781. ; 191:2, s. 98-111
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Journal article (peer-reviewed)abstract
- Frontostriatal circuit mediated cognitive dysfunction has been implicated in frontotemporal lobar degeneration (FTLD) and may differ across subtypes of FTLD. We manually segmented the neostriatum (caudate nucleus and putamen) in FTLD subtypes: behavioral variant frontotemporal dementia, FTD, n=12; semantic dementia, SD, n=13; and progressive non-fluent aphasia, PNFA, n=9); in comparison with controls (n=27). Diagnoses were based on international consensus criteria. Manual bilateral segmentation of the caudate nucleus and putamen was conducted blind to diagnosis by a single analyst, on MRI scans using a standardized protocol. Intracranial volume was calculated via a stereological point counting technique and was used for normalizing the shape analysis. Segmented binaries were analyzed using the Spherical Harmonic (SPHARM) Shape Analysis tools (University of North Carolina) to perform comparisons between FTLD subtypes and controls for global shape difference, local significance maps and mean magnitude maps of shape displacement. Shape analysis revealed that there was significant shape difference between FTLD subtypes and controls, consistent with the predicted frontostriatal dysfunction and of significant magnitude, as measured by displacement maps. These differences were not significant for SD compared to controls; lesser for PNFA compared to controls; whilst FTD showed a more specific pattern in regions relaying fronto- and corticostriatal circuits. Shape analysis shows regional specificity of atrophy, manifest as shape deflation, with a differential between FTLD subtypes, compared to controls.
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| 8. |
- Lucarelli, Andrea, 1982-
(author)
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The Political Dimension of Place Branding
- 2015
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Doctoral thesis (other academic/artistic)abstract
- Place branding is commonly understood as the application of marketing and commercial ideas, strategies, measurements and logic to the realm of places such as cities, regions and nations. Nevertheless, place branding is also understood as the locus where political activities – imbued with political impact and political effects – appear and affect the soft and hard infrastructures of urban agglomeration and other spatial environments. In this regard, by performing an analysis that helps unpack the multiple characters and impacts of political structures and processes in relation to place branding activities, the present dissertation aims to offer a conceptualization of the political dimension of place branding. By drawing on the critical assessment of the academic literature on place branding and on a series of studies about the branding processes in the region of Romagna and in the Greater Stockholm, the present dissertation further specifies an alternative conceptual framework (i.e. ecological politics) that suggests how place branding should be seen an empirical and theoretical political apparatus that acts, in praxis, based on an emerging, multifaceted and spatio-temporal enfolding of politics. More specifically, the ecological politics of place branding is characterized by four main aspects: the unfolding of a biopolitical ecology around place-branding practices; the ideological appropriation of place-branding processes; the positioning through politicized actions between the interest groups; and finally place-branding as a process of policy-intervention. Finally, on more general level, the present dissertation, by recognizing the political activities and efforts of place branding as crucial elements to be analyzed, makes the case for a more explicit, complex and manifold political analysis of the political dimension of place branding, which allows attention to be given to the impact that branding processes, practices and activities have on cities, regions and nations
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| 9. |
- Martin, Cederlöf, 1980-, et al.
(author)
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A longitudinal study of adolescent psychotic experiences and later development of substance use disorder and suicidal behavior
- 2017
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In: Schizophrenia Research. - Amsterdam, Netherlands : Elsevier. - 0920-9964 .- 1573-2509. ; 181, s. 13-16
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Journal article (peer-reviewed)abstract
- Introduction: Psychotic experiences are associated with later substance use disorder and suicidal behavior, but individual psychotic experiences have not been examined in a longitudinal data set. Also, the potential dose-response relationship between these phenomena remains unknown.Method: Cohort study including 9242 adolescents who participated in The Child and Adolescent Twin Study in Sweden (CATSS). At ages 15 and/or 18, seven psychotic experiences (auditory and visual hallucinations, and five delusions) were assessed via questionnaires. Outcomes at follow-up were physician-assigned diagnoses of substance use disorder and suicide attempts ascertained from the Swedish Patient Register. Associations were estimated with Cox regressions and expressed as hazard ratios.Results: All psychotic experiences were associated with later substance use disorder and/or suicide attempts, with hazard ratios ranging from 1.6 to 3.0. A dose-response relationship was observed between psychotic experiences and later substance use disorder, and suicide attempt.Discussion: Auditory and visual hallucinations as well as delusions in adolescence are associated with later development of substance use disorder and suicide attempt, and there is a dose-response relationship between the load of psychotic experiences and these adverse outcomes. Clinicians should assess subclinical hallucinations as well as delusions in psychiatric evaluations of adolescents.
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| 10. |
- Martin, Cederlöf, 1980-, et al.
(author)
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The association between childhood autistic traits and adolescent psychotic experiences is explained by general neuropsychiatric problems.
- 2016
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In: American Journal of Medical Genetics Part B. - Hoboken, USA : Wiley-Blackwell. - 1552-4841 .- 1552-485X. ; 171:2, s. 153-159
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Journal article (peer-reviewed)abstract
- Studies suggest associations between childhood autistic traits and adolescent psychotic experiences. However, recent research suggests that a general neuropsychiatric problems factor predicts adverse outcomes better than specific diagnostic entities. To examine if the alleged association between autistic traits and psychotic experiences could rather be explained by a general neuropsychiatric problems factor comprising symptoms of ADHD, tic disorder, developmental coordination disorder, and learning disorder, we conducted a prospective cohort study based on the Child and Adolescent Twin Study in Sweden. In addition, we examined the genetic and environmental influences on the associations. A total of 9,282 twins with data on childhood autistic traits and other neuropsychiatric problems, and follow-up data on psychotic experiences at ages 15 and/or 18 years were included. First, psychotic experiences were regressed on autistic traits and second, the general neuropsychiatric problems factor was added to the model. Auditory hallucinations were analyzed separately from the other psychotic experiences. Finally, twin analyses were employed to disentangle genetic from environmental influences in the observed associations. Replicating prior research, significant associations were found between autistic traits in childhood and auditory hallucinations at ages 15 and 18. However, after controlling for the general neuropsychiatric problems factor, the associations between autistic traits and auditory hallucinations disappeared, whereas the association between the general neuropsychiatric problems factor and auditory hallucinations persisted after controlling for autistic traits. Twin analyses revealed that the association between the general neuropsychiatric problems factor and auditory hallucinations was driven by shared genetic influences. .
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