TY - JOUR A1 - Baedke, Jan A1 - Schöttler, Tobias T1 - Visual Metaphors in the Sciences BT - the Case of Epigenetic Landscape Images JF - Journal for General Philosophy of Science N2 - Recent philosophical analyses of the epistemic dimension of images in the sciences show a certain trend in acknowledging potential roles of these images beyond their merely decorative or pedagogical functions. We argue, however, that this new debate has yet paid little attention to a special type of pictures, we call ‘visual metaphor’, and its versatile heuristic potential in organizing data, supporting communication, and guiding research, modeling, and theory formation. Based on a case study of Conrad Hal Waddington’s epigenetic landscape images in biology, we develop a descriptive framework applicable to heuristic roles of various visual metaphors in the sciences. KW - Conrad Hal Waddington KW - Epigenetic landscape KW - Modelling KW - Scientific images KW - Theory formation KW - Visual metaphor Y1 - 2017 U6 - https://doi.org/10.1007/s10838-016-9353-9 SN - 0925-4560 SN - 1572-8587 VL - 48 SP - 173 EP - 194 PB - Springer CY - Dordrecht ER - TY - INPR A1 - Murray, Wayne S. A1 - Fischer, Martin H. A1 - Tatler, Benjamin W. T1 - Serial and parallel processes in eye movement control - current controversies and future directions T2 - The quarterly journal of experimental psychology N2 - In this editorial for the Special Issue on Serial and Parallel Processing in Reading we explore the background to the current debate concerning whether the word recognition processes in reading are strictly serialsequential or take place in an overlapping parallel fashion. We consider the history of the controversy and some of the underlying assumptions, together with an analysis of the types of evidence and arguments that have been adduced to both sides of the debate, concluding that both accounts necessarily presuppose some weakening of, or elasticity in, the eyemind assumption. We then consider future directions, both for reading research and for scene viewing, and wrap up the editorial with a brief overview of the following articles and their conclusions. KW - Serial and parallel KW - Eye movements KW - Reading KW - Scene perception KW - Modality KW - Modelling KW - Eyemind assumption KW - Decoupling KW - Alan Kennedy Y1 - 2013 U6 - https://doi.org/10.1080/17470218.2012.759979 SN - 1747-0218 VL - 66 IS - 3 SP - 417 EP - 428 PB - Wiley CY - Hove ER - TY - JOUR A1 - Bronstert, Axel A1 - de Araujo, Josè Carlos A1 - Batalla Villanueva, Ramon J. A1 - Costa, Alexandre Cunha A1 - Delgado, José Miguel Martins A1 - Francke, Till A1 - Förster, Saskia A1 - Guentner, Andreas A1 - Lopez-Tarazon, José Andrés A1 - Mamede, George Leite A1 - Medeiros, Pedro Henrique Augusto A1 - Mueller, Eva A1 - Vericat, Damia T1 - Process-based modelling of erosion, sediment transport and reservoir siltation in mesoscale semi-arid catchments JF - Journal of soils and sediments : protection, risk assessment and remediation N2 - To support scientifically sound water management in dryland environments a modelling system has been developed for the quantitative assessment of water and sediment fluxes in catchments, transport in the river system, and retention in reservoirs. The spatial scale of interest is the mesoscale because this is the scale most relevant for management of water and land resources. This modelling system comprises process-oriented hydrological components tailored for dryland characteristics coupled with components comprising hillslope erosion, sediment transport and reservoir deposition processes. The spatial discretization is hierarchically designed according to a multi-scale concept to account for particular relevant process scales. The non-linear and partly intermittent run-off generation and sediment dynamics are dealt with by accounting for connectivity phenomena at the intersections of landscape compartments. The modelling system has been developed by means of data from nested research catchments in NE-Spain and in NE-Brazil. In the semi-arid NE of Brazil sediment retention along the topography is the main process for sediment retention at all scales, i.e. the sediment delivery is transport limited. This kind of deposition retains roughly 50 to 60 % of eroded sediment, maintaining a similar deposition proportion in all spatial scales investigated. On the other hand, the sediment retained in reservoirs is clearly related to the scale, increasing with catchment area. With increasing area, there are more reservoirs, increasing the possibility of deposition. Furthermore, the area increase also promotes an increase in flow volume, favouring the construction of larger reservoirs, which generally overflow less frequently and retain higher sediment fractions. The second example comprises a highly dynamic Mediterranean catchment in NE-Spain with nested sub-catchments and reveals the full dynamics of hydrological, erosion and deposition features. The run-off modelling performed well with only some overestimation during low-flow periods due to the neglect of water losses along the river. The simulated peaks in sediment flux are reproduced well, while low-flow sediment transport is less well captured, due to the disregard of sediment remobilization in the riverbed during low flow. This combined observation and modelling study deepened the understanding of hydro-sedimentological systems characterized by flashy run-off generation and by erosion and sediment transport pulses through the different landscape compartments. The connectivity between the different landscape compartments plays a very relevant role, regarding both the total mass of water and sediment transport and the transport time through the catchment. KW - Connectivity KW - Deposition KW - Erosion KW - Modelling KW - Sediment transfer KW - Semi-arid Y1 - 2014 U6 - https://doi.org/10.1007/s11368-014-0994-1 SN - 1439-0108 SN - 1614-7480 VL - 14 IS - 12 SP - 2001 EP - 2018 PB - Springer CY - Heidelberg ER - TY - THES A1 - Züllich, Gunda T1 - Migration and development in Senegal : a system dynamics analysis of the feedback relationships N2 - This thesis investigates the reciprocal relationship between migration and development in Senegal. Therewith, it contributes to the debate as to whether migration in developing countries enhances or rather impedes the development process. Even though extensive and controversial discussions can be found in the scientific literature regarding the impact of migration on development, research has scarcely examined the feedback relationships between migration and development. Science however agrees with both the fact that migration affects development as well as that the level of development in a country determines migration behaviour. Thus, both variables are neither dependent nor independent, but endogenous variables influencing each other and producing behavioural pattern that cannot be investigated using a static and unidirectional approach. On account of this, the thesis studies the feedback mechanisms existing between migration and development and the behavioural pattern generated by the high interdependence in order to be able to draw conclusions concerning the impact of changes in migration behaviour on the development process. To explore these research questions, the study applies the computer simulation method ‘System Dynamics’ and amplifies the simulation model for national development planning called ‘Threshold 21’ (T21), representing development processes endogenously and integrating economic, social and environmental aspects, using a structure that portrays the reasons and consequences of migration. The model has been customised to Senegal, being an appropriate representative of the theoretical interesting universe of cases. The comparison of the model generated scenarios - in which the intensity of emigration, the loss and gain of education, the remittances or the level of dependence changes - facilitates the analysis. The present study produces two important results. The first outcome is the development of an integrative framework representing migration and development in an endogenous way and incorporating several aspects of different theories. This model can be used as a starting point for further discussions and improvements and it is a fairly relevant and useful result against the background that migration is not integrated into most of the development planning tools despite its significant impact. The second outcome is the gained insights concerning the feedback relations between migration and development and the impact of changes in migration on development. To give two examples: It could be found that migration impacts development positively, indicated by HDI, but that the dominant behaviour of migration and development is a counteracting behaviour. That means that an increase in emigration leads to an improvement in development, while this in turn causes a decline in emigration, counterbalancing the initial increase. Another insight concerns the discovery that migration causes a decline in education in the short term, but leads to an increase in the long term, after approximately 25 years - a typical worse-before-better behaviour. From these and further observations, important policy implications can be derived for the sending and receiving countries. Hence, by overcoming the unidirectional perspective, this study contributes to an improved understanding of the highly complex relationship between migration and development and their feedback relations. N2 - Die vorliegende Arbeit untersucht das wechselseitige Verhältnis zwischen Migration und Entwicklung im Senegal. Damit soll ein Beitrag zu der Debatte geleistet werden, ob Migration in Entwicklungsländern den Entwicklungsprozess eher fördert oder verhindert. Während die Frage nach der Auswirkung von Migration auf Entwicklung in der Literatur ausgiebig und kontrovers diskutiert wird, hat sich die Forschung bisher kaum den Rückkopplungen zwischen Migration und Entwicklung gewidmet, obwohl sich die Wissenschaft sowohl darüber einig ist, dass Migration den Entwicklungsprozess beeinflusst, als auch, dass der Entwicklungsstand eines Land das Migrationsverhalten bestimmt. Folglich sind beide Variablen weder abhängig, noch unabhängige, sondern endogene Variablen, die sich gegenseitig beeinflussen und damit Verhaltensweisen produzieren, deren Erforschung ein statischer, unidirektionaler Ansatz nicht gerecht wird. Deswegen fragt diese Arbeit nach den Rückwirkungsmechanismen, die zwischen Migration und Entwicklung existieren, und nach den Verhaltensweisen, die durch die hohe Interdependenz entstehen, um daraus Rückschlüsse auf die Frage ziehen zu können, welchen Einfluss Änderungen im Migrationsverhalten auf den Entwicklungsprozess haben. Um diese Forschungsfragen zu untersuchen wurde die Computersimulationsmethode System Dynamics genutzt und das Simulationsmodell zur nationalen Entwicklungsplanung, das ‚Threshold 21’ (T21), das die Entwicklungsprozesse endogen darstellt und soziale, ökonomische sowie ökologische Aspekte miteinander verknüpft, um eine Struktur erweitert, welche die Gründe und Konsequenzen von Migration abbildet. Dies wurde an den Senegal, ein angemessener Repräsentant der theoretisch interessanten Grundgesamtheit, angepasst. Der Vergleich der mit dem Modell generierten Szenarien, in denen die Intensität der Abwanderung, des Bildungsverlustes, des Bildungsgewinns, der Geldüberweisungen, oder der Abhängigkeit verändert wurden, ermöglichte die Analyse. Die Studie bringt zwei wichtige Ergebnisse hervor. Erstens entwickelt sie ein umfangreiches Modell, das Migration und Entwicklung endogen erklärt und verschiedene theoretische Ansatzpunkte enthält. Dies kann sowohl als Grundlage für weitere Diskussion und Verbesserungen genutzt werden, ist aber vor allem vor dem Hintergrund, dass Migration in den meisten Modellen zur Entwicklungsplanung trotz des relevanten Einflusses nicht integriert ist, ein wichtiges und nützliches Resultat. Zweitens konnte die Analyse des Verhaltens des Modells wichtige Erkenntnisse bezüglich der Rückwirkungsmechanismen zwischen Migration und Entwicklung und der Wirkung von Veränderungen in Migration auf Entwicklung erzielen. Um zwei Beispiele zu nennen, wurde herausgearbeitet, dass Migration sich positiv auf Entwicklung, gemessen am Human Development Index (HDI), auswirkt, dass es sich aber generell um ein sich ausgleichendes Verhalten handelt, da die positiven Einflüsse auf Entwicklung ihrerseits Migration verringern, wodurch die positiven Einflüsse wieder abnehmen. Ebenso konnte festgestellt werden, dass Migration für das Bildungsniveau zunächst eine Verschlechterung, später aber, nach ca. 25 Jahren, eine Verbesserung nach sich zieht. Aus diesen und weiteren Beobachtungen können wichtige Politikempfehlungen für die Sende- und Empfängerländer von Migration abgeleitet werden. Durch das Überwinden der unidirektionalen Betrachtungsweise trägt diese Arbeit somit zu einem besseren Verständnis des hoch komplexen und von Rückwirkungsmechanismen geprägten Verhältnisses zwischen Migration und Entwicklung bei. KW - Internationale Migration KW - Nachhaltige Entwicklung KW - Senegal KW - System Dynamics KW - Modellierung KW - International Migration KW - Sustainable Development KW - Senegal KW - System Dynamics KW - Modelling Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-57836 ER - TY - JOUR A1 - Heckmann, Tobias A1 - Schwanghart, Wolfgang A1 - Phillips, Jonathan D. T1 - Graph theory-recent developments of its application in geomorphology JF - Geomorphology : an international journal on pure and applied geomorphology N2 - Applications of graph theory have proliferated across the academic spectrum in recent years. Whereas geosciences and landscape ecology have made rich use of graph theory, its use seems limited in physical geography, and particularly in geomorphology. Common applications of graph theory analyses of connectivity, path or transport efficiencies, subnetworks, network structure, system behaviour and dynamics, and network optimization or engineering all have uses or potential uses in geomorphology and closely related fields. In this paper, we give a short introduction to graph theory and review previous geomorphological applications or works in related fields that have been particularly influential. Network-like geomorphic systems can be classified into nonspatial or spatially implicit system components linked by statistical/causal relationships and spatial units linked by some spatial relationship, for example by fluxes of matter and/or energy. We argue that, if geomorphic system properties and behaviour (e.g., complexity, sensitivity, synchronisability, historical contingency, connectivity etc.) depend on system structure and if graph theory is able to quantitatively describe the configuration of system components, then graph theory should provide us with tools that help in quantifying system properties and in inferring system behaviour. (C) 2015 Elsevier B.V. All rights reserved. KW - Graph theory KW - Network analysis KW - Spatial and nonspatial graphs KW - Geomorphic systems KW - Modelling Y1 - 2015 U6 - https://doi.org/10.1016/j.geomorph.2014.12.024 SN - 0169-555X SN - 1872-695X VL - 243 SP - 130 EP - 146 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Eldridge, Tilly A1 - Langowski, Lukasz A1 - Stacey, Nicola A1 - Jantzen, Friederike A1 - Moubayidin, Laila A1 - Sicard, Adrien A1 - Southam, Paul A1 - Kennaway, Richard A1 - Lenhard, Michael A1 - Coen, Enrico S. A1 - Ostergaard, Lars T1 - Fruit shape diversity in the Brassicaceae is generated by varying patterns of anisotropy JF - Development : Company of Biologists N2 - Fruits exhibit a vast array of different 3D shapes, from simple spheres and cylinders to more complex curved forms; however, the mechanism by which growth is oriented and coordinated to generate this diversity of forms is unclear. Here, we compare the growth patterns and orientations for two very different fruit shapes in the Brassicaceae: the heart-shaped Capsella rubella silicle and the near-cylindrical Arabidopsis thaliana silique. We show, through a combination of clonal and morphological analyses, that the different shapes involve different patterns of anisotropic growth during three phases. These experimental data can be accounted for by a tissue level model in which specified growth rates vary in space and time and are oriented by a proximodistal polarity field. The resulting tissue conflicts lead to deformation of the tissue as it grows. The model allows us to identify tissue-specific and temporally specific activities required to obtain the individual shapes. One such activity may be provided by the valve-identity gene FRUITFULL, which we show through comparative mutant analysis to modulate fruit shape during post-fertilisation growth of both species. Simple modulations of the model presented here can also broadly account for the variety of shapes in other Brassicaceae species, thus providing a simplified framework for fruit development and shape diversity. KW - Brassicaceae KW - Capsella KW - Arabidopsis KW - Fruit shape KW - Modelling KW - Anisotropic growth Y1 - 2016 U6 - https://doi.org/10.1242/dev.135327 SN - 0950-1991 SN - 1477-9129 VL - 143 SP - 3394 EP - 3406 PB - Company of Biologists Limited CY - Cambridge ER - TY - JOUR A1 - Streich, Rita A1 - Becken, Michael T1 - Electromagnetic fields generated by finite-length wire sources: comparison with point dipole solutions JF - Geophysical prospecting N2 - In present-day land and marine controlled-source electromagnetic (CSEM) surveys, electromagnetic fields are commonly generated using wires that are hundreds of metres long. Nevertheless, simulations of CSEM data often approximate these sources as point dipoles. Although this is justified for sufficiently large source-receiver distances, many real surveys include frequencies and distances at which the dipole approximation is inaccurate. For 1D layered media, electromagnetic (EM) fields for point dipole sources can be computed using well-known quasi-analytical solutions and fields for sources of finite length can be synthesized by superposing point dipole fields. However, the calculation of numerous point dipole fields is computationally expensive, requiring a large number of numerical integral evaluations. We combine a more efficient representation of finite-length sources in terms of components related to the wire and its end points with very general expressions for EM fields in 1D layered media. We thus obtain a formulation that requires fewer numerical integrations than the superposition of dipole fields, permits source and receiver placement at any depth within the layer stack and can also easily be integrated into 3D modelling algorithms. Complex source geometries, such as wires bent due to surface obstructions, can be simulated by segmenting the wire and computing the responses for each segment separately. We first describe our finite-length wire expressions and then present 1D and 3D examples of EM fields due to finite-length sources for typical land and marine survey geometries and discuss differences to point dipole fields. KW - Electromagnetics KW - Mathematical formulation KW - Modelling KW - Numerical study Y1 - 2011 U6 - https://doi.org/10.1111/j.1365-2478.2010.00926.x SN - 0016-8025 VL - 59 IS - 2 SP - 361 EP - 374 PB - Wiley-Blackwell CY - Malden ER - TY - JOUR A1 - Bäckemo, Johan Dag Valentin A1 - Liu, Yue A1 - Lendlein, Andreas T1 - Bio-inspired and computer-supported design of modulated shape changes in polymer materials JF - MRS communications / a publication of the Materials Research Society N2 - The Venus flytrap is a fascinating plant with a finely tuned mechanical bi-stable system, which can switch between mono- and bi-stability. Here, we combine geometrical design of compliant mechanics and the function of shape-memory polymers to enable switching between bi- and mono-stable states. Digital design and modelling using the Chained Beam Constraint Model forecasted two geometries, which were experimentally realized as structured films of cross-linked poly[ethylene-co-(vinyl acetate)] supported by digital manufacturing. Mechanical evaluation confirmed our predicted features. We demonstrated that a shape-memory effect could switch between bi- and mono-stability for the same construct, effectively imitating the Venus flytrap. KW - Additive manufacturing KW - Biomimetic KW - Shape memory KW - Modelling KW - Polymer Y1 - 2021 U6 - https://doi.org/10.1557/s43579-021-00056-6 SN - 2159-6867 VL - 11 IS - 4 SP - 462 EP - 469 PB - Springer CY - Berlin ER -