Amoeba Techniques for Shape and Texture Analysis

Morphological amoebas are image-adaptive structuring elements for morphological and other local image filters introduced by Lerallut et al. Their construction is based on combining spatial distance with contrast information into an image-dependent metric. Amoeba filters show interesting parallels to image filtering methods based on partial differential equations (PDEs), which can be confirmed by asymptotic equivalence results. In computing amoebas, graph structures are generated that hold information about local image texture. This paper reviews and summarises the work of the author and his coauthors on morphological amoebas, particularly their relations to PDE filters and texture analysis. It presents some extensions and points out directions for future investigation on the subject.Comment: 38 pages, 19 figures v2: minor corrections and rephrasing, Section 5 (pre-smoothing) extende

Conditionally complete sponges: new results on generalized lattices

Sponges were recently proposed as a generalization of lattices, focussing on joins/meets of sets, while letting go of associativity/transitivity. In this work we provide tools for characterizing and constructing sponges on metric spaces and groups. These are then used in a characterization of epigraph sponges: a new class of sponges on Hilbert spaces whose sets of left/right bounds are formed by the epigraph of a rotationally symmetric function. We also show that the so-called hyperbolic sponge generalizes to more than two dimensions.Comment: 24 page

New binaries from the SHINE survey

Stars and planetary system

A study of land transformation in Savar Upazila, Bangladesh, 1915-2001 : an integrated approach using remote sensing, census, map and field data

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Probing the Role of AGN Feedback and Galactic Mergers in Galaxy Evolution

In this thesis we aim to probe the role of two of the processes that can dictate the evolution of galaxies – feedback from the central active galactic nucleus (AGN) and mergers. To study the importance of AGN feedback and, in particular, its most direct manifestation as galactic-scale cold-gas winds we assembled two carefully matched large samples of nearby galaxies with and without the presence of optical unobscured Seyfert 2 active galactic nucleus activity. To infer and quantify the presence of such galactic kpc-scale outflows we then studied and compared the properties of the interstellar Na i λλ5890,5895 (NaD) absorption-line doublet, present in some of these systems. We detected excess interstellar NaD absorption in a similar fraction of galaxies in both of our samples. We identified only 53 (or 0.5% of the population) of our Seyfert 2 AGN galaxies potentially harbor outflows. Moreover, in a large fraction of these 53 Seyfert 2s, available ancillary radio and infrared data indicated that star-formation may actually be the principal driver of the outflows. Our results suggest that galactic-scale winds at low redshift are no more frequent in Seyfert 2s than they are in their control-sample counterparts and that optical AGNs are not direct significant contributors to the quenching of star formation in the nearby Universe. On the other hand, to investigate the impact that mergers can have on galaxy evolution we have focused on two galaxies that show signatures of embedded counter-rotating components. Such features are believed to be the fossil records of a past gas acquisition events or a merger. We have successfully separated the contributions of the two distinct kinematic components to the spectra in one of them NGC 448. Drawing on this separation we have shown that the two decoupled stellar components in NGC 448 have similar ages, but different chemical compositions. Our findings indicate that the kinematically distinct component in NGC 448 is truly decoupled, has external origin, and was formed through either the acquisition of gas and a subsequent star-formation episode or from the direct accretion of stars from a companion. Conversely, the presence of a kinematically distinct component in NGC 4365 is not associated to a true kinematic decoupling and is instead most likely due to a projection effect stemming from the triaxial nature of this galaxy. We have also used two samples from a large integral-field spectroscopic survey to verify some of our previous finding and study the demographics of galaxies with embedded counterrotating components. We have performed some preliminary analysis of this data. The results of this investigation confirm the validity of our method for the detection of cold-gas flows in our Seyfert 2 and control samples. Finally, we have verified some previously known trends in the demographics and properties of galaxies that display stellar counter-rotation as inferred by integral-field observations. On the other hand, our analysis is in contrast with previous studies that have observed that the presence of a counter-rotating stellar component is associated rather frequently with the presence of counter-rotating gas traced by nebular emission

Metropolitan Research: Methods and Approaches

Metropolitan research requires multidisciplinary perspectives in order to do justice to the complexities of metropolitan regions. This volume provides a scholarly and accessible overview of key methods and approaches in metropolitan research from a uniquely broad range of disciplines including architectural history, art history, heritage conservation, literary and cultural studies, spatial planning and planning theory, geoinformatics, urban sociology, economic geography, operations research, technology studies, transport planning, aquatic ecosystems research and urban epidemiology. It is this scope of disciplinary - and increasingly also interdisciplinary - approaches that allows metropolitan research to address recent societal challenges of urban life, such as mobility, health, diversity or sustainability

Metropolitan Research

Metropolitan research requires multidisciplinary perspectives in order to do justice to the complexities of metropolitan regions. This volume provides a scholarly and accessible overview of key methods and approaches in metropolitan research from a uniquely broad range of disciplines including architectural history, art history, heritage conservation, literary and cultural studies, spatial planning and planning theory, geoinformatics, urban sociology, economic geography, operations research, technology studies, transport planning, aquatic ecosystems research and urban epidemiology. It is this scope of disciplinary - and increasingly also interdisciplinary - approaches that allows metropolitan research to address recent societal challenges of urban life, such as mobility, health, diversity or sustainability

Role of complement genetic variants in inflammatory diseases by an interactive database and protein structure modelling

The rare diseases atypical haemolytic uraemic syndrome (aHUS) and C3 glomerulopathy (C3G) are associated with dysregulation of complement activation. It is unclear which genes most frequently predispose to aHUS or C3G. Accordingly, a six- centre analysis of 610 rare genetic variants in 13 mostly complement genes from >3500 patients with aHUS and C3G was performed. A new interactive Database of Complement Gene Variants was developed to extract allele frequencies for these 13 genes using the Exome Aggregation Consortium server as the reference genome. For aHUS, significantly more protein-altering rare variation was found in the five genes CFH, CFI, CD46, C3 and DGKE than in ExAC. For C3G, an association was only found for rare variants in C3 and the N-terminal C3b-binding or C-terminal non-surface-associated regions of factor H (FH). FH is the major regulator of C3b and its Tyr402His polymorphism is an age-related macular degeneration risk-factor. To better understand FH complement binding, the solution structures of both allotypes were studied. Starting from known FH short complement regulator domains and glycan structures, small angle X-ray scattering data were fitted using Monte Carlo methods to determine atomistic structures for monomeric FH. The analysis of 29,715 physically realistic but randomised FH conformations resulted in 100 similar best-fit FH structures for each allotype. Two distinct molecular structures resulted; an extended N-terminal domain arrangement with a folded-back C-terminus, or an extended C-terminus and folded-back N-terminus. To clarify FH functional roles in host protection, crystal structures for the FH complexes with C3b and C3dg revealed that the extended N-terminal conformation accounted for C3b fluid phase regulation, the extended C-terminal conformation accounted for C3d binding, and both conformations accounted for bivalent FH binding to the host cell-surface. Finally, statistical analyses indicated that the structural location of rare variants in complement may predict the occurrences of aHUS or C3G