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- Thompson, Paul M., et al.
(author)
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The ENIGMA Consortium : large-scale collaborative analyses of neuroimaging and genetic data
- 2014
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In: BRAIN IMAGING BEHAV. - : Springer Science and Business Media LLC. - 1931-7557 .- 1931-7565. ; 8:2, s. 153-182
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Journal article (peer-reviewed)abstract
- The Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) Consortium is a collaborative network of researchers working together on a range of large-scale studies that integrate data from 70 institutions worldwide. Organized into Working Groups that tackle questions in neuroscience, genetics, and medicine, ENIGMA studies have analyzed neuroimaging data from over 12,826 subjects. In addition, data from 12,171 individuals were provided by the CHARGE consortium for replication of findings, in a total of 24,997 subjects. By meta-analyzing results from many sites, ENIGMA has detected factors that affect the brain that no individual site could detect on its own, and that require larger numbers of subjects than any individual neuroimaging study has currently collected. ENIGMA's first project was a genome-wide association study identifying common variants in the genome associated with hippocampal volume or intracranial volume. Continuing work is exploring genetic associations with subcortical volumes (ENIGMA2) and white matter microstructure (ENIGMA-DTI). Working groups also focus on understanding how schizophrenia, bipolar illness, major depression and attention deficit/hyperactivity disorder (ADHD) affect the brain. We review the current progress of the ENIGMA Consortium, along with challenges and unexpected discoveries made on the way.
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- Backé, Eva-Maria, et al.
(author)
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The role of psychosocial stress at work for the development of cardiovascular diseases : a systematic review.
- 2012
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In: International Archives of Occupational and Environmental Health. - Berlin : Springer Berlin/Heidelberg. - 0340-0131 .- 1432-1246. ; 85:1, s. 67-79
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Journal article (peer-reviewed)abstract
- PURPOSE: A systematic review was carried out to assess evidence for the association between different models of stress at work, and cardiovascular morbidity and mortality. METHODS: A literature search was conducted using five databases (MEDLINE, Cochrane Library, EMBASE, PSYNDEX and PsycINFO). Inclusion criteria for studies were the following: self-reported stress for individual workplaces, prospective study design and incident disease (myocardial infarction, stroke, angina pectoris, high blood pressure). Evaluation, according to the criteria of the Scottish Intercollegiate Guidelines Network, was done by two readers. In case of disagreement, a third reader was involved. RESULTS: Twenty-six publications were included, describing 40 analyses out of 20 cohorts. The risk estimates for work stress were associated with a statistically significant increased risk of cardiovascular disease in 13 out of the 20 cohorts. Associations were significant for 7 out of 13 cohorts applying the demand-control model, all three cohorts using the effort-reward model and 3 out of 6 cohorts investigating other models. Most significant results came from analyses considering only men. Results for the association between job stress and cardiovascular diseases in women were not clear. Associations were weaker in participants above the age of 55. CONCLUSIONS: In accordance with other systematic reviews, this review stresses the importance of psychosocial factors at work in the aetiology of cardiovascular diseases. Besides individual measures to manage stress and to cope with demanding work situations, organisational changes at the workplace need to be considered to find options to reduce occupational risk factors for cardiovascular diseases.
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3. |
- Bauer, Friederike U., et al.
(author)
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Tracing the exhumation history of the Rwenzori Mountains, Albertine Rift, Uganda, using low-temperature thermochronology
- 2013
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In: Tectonophysics. - : Elsevier BV. - 0040-1951 .- 1879-3266. ; 599, s. 8-28
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Journal article (peer-reviewed)abstract
- The Rwenzori Mtns form a striking feature within the Albertine Rift of the East African Rift System. They are made up of a dissected Precambrian metamorphic basement block reaching heights of more than 5 km. Applying low-temperature therrnochronology a complex exhumation history becomes evident, where rock and surface uplift can be traced from Palaeozoic to Neogene times. Fission-track and (U-Th-Sm)/He cooling ages and derived cooling histories allow distinguishing different blocks in the Rwenzori Mtns. In the central part a northern and a southern block are separated by a putative NW-SE trending fault; with the northern block showing distinctly younger apatite fission-track ages (similar to 130 Ma) than the southern block (similar to 300 Ma). Cooling ages in both blocks do not vary significantly with elevation, despite considerable differences in elevation. Thermal history modelling reflects protracted cooling histories. Modelled t-T paths show decoupled blocks that were relocated separately along distinct fault planes, which reactivated pre-existing structures, inherited from Palaeozoic folding and thrusting. Initial cooling affected the Rwenzori area in Silurian to Devonian times, followed by Mesozoic and Cainozoic cooling events. Pre-Neogene evolution seems to be triggered by tectonic processes like the opening of the Indian Ocean and the south Atlantic. From thermochronological data the formation of a Mesozoic Albertine high is conceivable. In Cainozoic times the area was affected by rifting, resulting in differentiated surface uplift. Along the western flank of the Rwenzori Mtns, surface uplift was more pronounced. This is also reflected in their recent topography, formed by accelerated rock uplift in the near past (Pliocene to Pleistocene). Erosion could not compensate for this most recent uplift, resulting in apatite He ages of Oligocene to Miocene age or even older.
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4. |
- Holtermann, R., et al.
(author)
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A Hybrid Approach to the Modelling and Simulation of Grinding Processes
- 2014
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In: Proceedings of the 11th World Congress on Computational Mechanics (WCCM XI); 5th European Conference on Computational Mechanics (ECCM V); 6th European Conference on Computational Fluid Dynamics (ECFD VI). - 9788494284472 ; , s. 1932-1937
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Conference paper (peer-reviewed)abstract
- We present recent advances in the modelling and simulation of Internal Traverse Grinding, a high performance grinding process incorporating a high rate of material removal combined with a high surface quality. Due to a special grinding wheel geometry, the latter two goals are achieved in just one pass of the tool through the axisymmetric workpiece. The simulation framework we present generally consists of three components. The first one is a parametric plane strain, h-adaptive finite element model capturing the material penetration of a single cBN grain on a meso-scale during the machining process. Secondly, a topography analysis procedure as well as a kinematic simulation have been developed to measure and analyse the surface topography of an actual grinding wheel. We then use this information to model the grinding wheel surface in the latter kinematic simulation. This enables us to perform an exact calculation of the transient penetration history of every grain intersecting with the workpiece bulk. The superposition of these results is then used in the third component of the simulation framework, namely a process scale workpiece model currently under development which captures the effects of thermo-mechanical loads on the workpiece undergoing material removal and thus, in the near future, shall enable us to predict potential unwanted phase transformations of the bulk surface as well as size and shape errors of the finished part. In this contribution, we will focus on the first two parts of the simulation framework, namely the meso-scale as well as the kinematic simulation and the coupling between the two scales.
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6. |
- Jusufi, Ilir
(author)
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Towards the Visualization of Multivariate Biochemical Networks
- 2012
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Licentiate thesis (other academic/artistic)abstract
- Many open challenges exist when dealing with different biological networks. They are crucial for the understanding of living beings. Complete drawings of these typically large networks usually suffer from clutter and visual overload. In order to overcome this issue, the networks are divided into single, hierarchically structured pathways. However, this subdivision makes it harder to navigate and understand the connections between pathways. Another challenge is to visualize ontologies and hierarchical clusterings, which are important tools to study high-throughput data that are automatically generated nowadays. Both of these methods produce different types of large graphs. Although these methods are used to explore the same data set, they are usually considered independently. Therefore, a combined view showing the results of both methods is desired. Additionally, real life data sets, including biological networks, usually have additional attributes related to the considered network. Investigating means to visualize such multivariate data together with the network drawing is also one of the ongoing challenges in biology, but also in other fields.The aim of this thesis is to lay out the foundations towards defining techniques for the visualization of multivariate biochemical networks. An overall understanding of the problems related to biochemical networks should be acquired to achieve this aim. More importantly, a contribution to the aforementioned challenges is necessary.Two research goals have been defined to accomplish our aim: for the first goal, we should improve shortcomings of the approach of dividing larger biological networks into smaller pieces and contribute to the problem of a visualization of different types of interconnected biological networks. The second goal is a contribution for the visualization of multivariate biological networks.Initially, a brief survey on techniques to visualize multivariate networks is presented in this thesis. Then, various visualization and interaction techniques are presented that address the challenges in biochemical network analysis. Three different software tools were implemented to demonstrate our research efforts. We discuss all features of our systems in detail, describe the visualization and interaction techniques as well as disadvantages and scalability issues if present.
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7. |
- Raphael, Holtermann, et al.
(author)
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Modelling, simulation and experimental investigation of chip formation in internal traverse grinding
- 2013
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In: Production Engineering. - : Springer Science and Business Media LLC. - 0944-6524 .- 1863-7353. ; 7:2-3, s. 251-263
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Journal article (peer-reviewed)abstract
- We present recent developments in modelling and simulation of internal traverse grinding, a high speed machining process which enables both a large material removal rate and high surface quality. We invoke a hybrid modelling framework, including a process scale model, simulations on a mesoscale capturing the proximity of a single cBN grain and an analysis framework to investigate the grinding wheel topography. Moreover, we perform experiments to verify our simulations. Focus in this context is the influence of the cutting speed variation on the grain specific heat generation.
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8. |
- Schumann, Barbara, et al.
(author)
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Lifestyle factors and lumbar disc disease : results of a German multi-center case-control study (EPILIFT).
- 2010
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In: Arthritis Research & Therapy. - : Springer Science and Business Media LLC. - 1478-6362. ; 12:5, s. R193-
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Journal article (peer-reviewed)abstract
- INTRODUCTION: In the large-scale case-control study EPILIFT, we investigated the dose-response relationship between lifestyle factors (weight, smoking amount, cumulative duration of different sports activities) and lumbar disc disease.METHODS: In four German study regions (Frankfurt am Main, Freiburg, Halle/Saale, Regensburg), 564 male and female patients with lumbar disc herniation and 351 patients with lumbar disc narrowing (chondrosis) aged 25 to 70 years were prospectively recruited. From the regional population registers, 901 population control subjects were randomly selected. In a structured personal interview, we enquired as to body weight at different ages, body height, cumulative smoking amount and cumulative duration of different sports activities. Confounders were selected according to biological plausibility and to the change-in-estimate criterion. Adjusted, gender-stratified odds ratios with 95% confidence intervals were calculated using unconditional logistic regression analysis.RESULTS: The results of this case-control study reveal a positive association between weight and lumbar disc herniation as well as lumbar disc narrowing among men and women. A medium amount of pack-years was associated with lumbar disc herniation and narrowing in men and women. A non-significantly lowered risk of lumbar disc disease was found in men with high levels of cumulative body building and strength training.CONCLUSIONS: According to our multi-center case-control study, body weight might be related to lumbar disc herniation as well as to lumbar disc narrowing. Further research should clarify the potential protective role of body building or strength training on lumbar disc disease.
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