398 research outputs found
Field-based measurement of hydrodynamics associated with engineered in-channel structures: the example of fish pass assessment
The construction of fish passes has been a longstanding measure to improve
river ecosystem status by ensuring the passability of weirs, dams and other in-
channel structures for migratory fish. Many fish passes have a low biological
effectiveness because of unsuitable hydrodynamic conditions hindering fish to
rapidly detect the pass entrance. There has been a need for techniques to
quantify the hydrodynamics surrounding fish pass entrances in order to identify
those passes that require enhancement and to improve the design of new
passes. This PhD thesis presents the development of a methodology for the
rapid, spatially continuous quantification of near-pass hydrodynamics in the
field. The methodology involves moving-vessel Acoustic Doppler Current
Profiler (ADCP) measurements in order to quantify the 3-dimensional water
velocity distribution around fish pass entrances. The approach presented in this
thesis is novel because it integrates a set of techniques to make ADCP data
robust against errors associated with the environmental conditions near
engineered in-channel structures. These techniques provide solutions to
(i) ADCP compass errors from magnetic interference, (ii) bias in water velocity
data caused by spatial flow heterogeneity, (iii) the accurate ADCP positioning in
locales with constrained line of sight to navigation satellites, and (iv) the
accurate and cost-effective sensor deployment following pre-defined sampling
strategies. The effectiveness and transferability of the methodology were
evaluated at three fish pass sites covering conditions of low, medium and high
discharge. The methodology outputs enabled a detailed quantitative
characterisation of the fish pass attraction flow and its interaction with other
hydrodynamic features. The outputs are suitable to formulate novel indicators of
hydrodynamic fish pass attractiveness and they revealed the need to refine
traditional fish pass design guidelines
Automated identification of river hydromorphological features using UAV high resolution aerial imagery
European legislation is driving the development of methods for river ecosystem protection in light of concerns over water quality and ecology. Key to their success is the accurate and rapid characterisation of physical features (i.e., hydromorphology) along the river. Image pattern recognition techniques have been successfully used for this purpose. The reliability of the methodology depends on both the quality of the aerial imagery and the pattern recognition technique used. Recent studies have proved the potential of Unmanned Aerial Vehicles (UAVs) to increase the quality of the imagery by capturing high resolution photography. Similarly, Artificial Neural Networks (ANN) have been shown to be a high precision tool for automated recognition of environmental patterns. This paper presents a UAV based framework for the identification of hydromorphological features from high resolution RGB aerial imagery using a novel classification technique based on ANNs. The framework is developed for a 1.4 km river reach along the river Dee in Wales, United Kingdom. For this purpose, a Falcon 8 octocopter was used to gather 2.5 cm resolution imagery. The results show that the accuracy of the framework is above 81%, performing particularly well at recognising vegetation. These results leverage the use of UAVs for environmental policy implementation and demonstrate the potential of ANNs and RGB imagery for high precision river monitoring and river management
Reticulons 3 and 6 interact with viral movement proteins
Funding; This research was funded by the Science and Technology Facilities Council Programme (grant no. 14230008), a British Biotechnology and Biological Sciences Research Council (grant no. BB/J004987/1 to Professor Chris Hawes), and a Vice-Chancellors Research Fellowship to V.K. Parts of this work were funded by the U.K. Biotechnology and Biomedical Sciences Research Council (BBSRC) grant BB/M007200/1 to J.T. Work in J.T.'s laboratory is supported by the Scottish Government's Rural and Environment Science and Analytical Services Division (RESAS).Plant reticulon (RTN) proteins are capable of constricting membranes and are vital for creating and maintaining tubules in the endoplasmic reticulum (ER), making them prime candidates for the formation of the desmotubule in plasmodesmata (PD). RTN3 and RTN6 have previously been detected in an Arabidopsis PD proteome and have been shown to be present in primary PD at cytokinesis. It has been suggested that RTN proteins form protein complexes with proteins in the PD plasma membrane and desmotubule to stabilize the desmotubule constriction and regulate PD aperture. Viral movement proteins (vMPs) enable the transport of viruses through PD and can be ER-integral membrane proteins or interact with the ER. Some vMPs can themselves constrict ER membranes or localize to RTN-containing tubules; RTN proteins and vMPs could be functionally linked or potentially interact. Here we show that different vMPs are capable of interacting with RTN3 and RTN6 in a membrane yeast two-hybrid assay, coimmunoprecipitation, and Förster resonance energy transfer measured by donor excited-state fluorescence lifetime imaging microscopy. Furthermore, coexpression of the vMP CMV-3a and RTN3 results in either the vMP or the RTN changing subcellular localization and reduces the ability of CMV-3a to open PD, further indicating interactions between the two proteins.Publisher PDFPeer reviewe
Defining the dance: Quantification and classification of ER dynamics
The availability of quantification methods for sub-cellular organelle dynamic analysis has increased rapidly over the last 20 years. The application of these techniques to contiguous sub-cellular structures that exhibit dynamic re-modelling over a range of scales and orientations is challenging as quantification of ‘movement’ rarely corresponds to traditional, qualitative classifications of types of organelle movement. The plant endoplasmic reticulum represents a particular challenge for dynamic quantification as it itself is an entirely contiguous organelle that is in a constant state of flux and gross remodelling, controlled by the actinomyosin cytoskeleton
The plant endoplasmic reticulum: An organized chaos of tubules and sheets with multiple functions
The endoplasmic reticulum (ER) is a fascinating organelle at the core of the secretory pathway. It is responsible for the synthesis of one third of the cellular proteome and, in plant cells, it produces receptors and transporters of hormones as well as the proteins responsible for the biosynthesis of critical components of a cellulosic cell wall. The ER structure resembles a spider-web network of interconnected tubules and cisternae that pervades the cell. The study of the dynamics and interaction of this organelles with other cellular structures such as the plasma membrane, the Golgi apparatus and the cytoskeleton, have been permitted by the implementation of fluorescent protein and advanced confocal imaging. In this review, we report on the findings that contributed toward the understanding of the ER morphology and function with the aid of fluorescent proteins, focusing on the contributions provided by pioneering work from the lab of the late Professor Chris Hawes
Labeling the ER for Light and Fluorescence Microscopy
The ER is a highly dynamic network of tubules and membrane sheets. Hence imaging this organelle in its native and mobile state is of great importance. Here we describe methods of labeling the native ER using fluorescent proteins and lipid dyes as well as methods for immunolabeling on plant tissue
Analyse der Knochendeformation und Muskelkräfte der menschlichen Tibia
Für die Erforschung des Weltraums durch den Menschen, aber auch für
die Gesundheit auf der Erde allgemein, ist ein grundlegendes Verständnis
über die Adaption des Knochens essentiell. Die Regulierung des Auf- und
Abbaus des Knochens wird über seine Deformation gesteuert, welche
wiederum aus der mechanischen Belastung dessen resultiert. Diese
Zusammenhänge zu verstehen, die Auswirkungen von verschiedenen
Aktivitäten auf die Deformation des Knochens zu kennen und in Relation
setzten zu können, ist der Schlüssel zu dem gesuchten, grundlegenden
Verständnis.
Im Zuge dieser Arbeit wurde hierfür eine Methode entwickelt, diese
Zusammenhänge qualitativ und quantitativ herzuleiten. Basierend auf in
vivo Messungen an der Tibia wurde ein Algorithmus zur in silico Analyse
der vorliegenden Daten entwickelt. Dieser macht sich die Konsequenzen
des Hookeschen Gesetzes in Form des Superpositionsprinzips zu Nutze,
um quasi-invers aus der gemessenen Deformationsbewegung die dafür
notwendigen Kräfte zu bestimmen. Diese können in einer Finite Elemente
Analyse (FEA) mit den rekonstruierten Tibia-Knochen verwendet werden,
um deren Spannungs-Dehnungs-Zustand zu bestimmen.
Zur Validierung der Annahmen und Randbedingungen des Algorithmus
wurde ein biomechanischer Messstand konstruiert. In diesem konnten in
replica und ex vivo Untersuchungen durchgeführt werden. Zu diesem
Zweck wurden Tibia-Replikate aus Komposite-Material bzw. Leichenbeine
künstlich über Aktuatoren mit Kräften beaufschlagt und über eine
spezielle Anwendung von Motion Capturing die Deformationsbewegung
des Knochens gemessen.
Die Auswertung der in vivo Daten mittels der in silico Analyse lieferte
quantitative Ergebnisse zur Dehnung in der Tibia für diverse alltägliche
Aktivitäten. Diese Ergebnisse sind, im Gegensatz zur bisherigen gängigen
Methode, jedoch nicht auf einen singulären Messpunkt limitiert, sondern
decken den kompletten rekonstruierten Bereich der Tibia ab. Dies führte
zur Feststellung, dass die aktuell angenommenen Werte zu niedrig
angesetzt sind. Hinzu kommt, dass die Analyse eine zeitliche und örtliche
Varianz der Peak-Dehnungen im Knochen über den Ablauf einer Aktivität
aufzeigt. Diese Ergebnisse verändern das bisherige Verständnis über die
Knochenadaption und deren Regulierungsmechanismen
Das Aufführungsformat Festival unter besonderer Berücksichtigung der Neuen Musik in Österreich
In der vorliegenden Arbeit wird das Phänomen Festival als wichtiges Aufführungsformat in der Musik, insbesondere unter Betrachtung des Genres der Neuen Musik, behandelt.
Anhand wichtiger Beispiele aus dem deutschsprachigen Raum wird auf die Geschichte des
Musikfestivals eingegangen sowie die Rolle der Neuen Musik im Festivalbetrieb diskutiert
und bedeutende Institutionen und Merkmale beschrieben. Einen weiteren wichtigen Aspekt
stellt der Aufführungskontext des (Musik-)Festivals dar, der durch einen geschichtlichen
Abriss des Wandels des Konzertwesens veranschaulicht wird. Vor diesem Hintergrund
wird zudem auf wichtige Elemente, wie etwa die Programmgestaltung und das Publikum
sowie auch auf Kulturpolitik und Musikvermittlung näher eingegangen. Abschließend
porträtiert ein umfassendes Resümee dreier ausgewählter Neue Musik-Festivals
stellvertretend die österreichische Festivalsituation und stellt diese im Kontext der zuvor
genannten Punkte dar. Schlussfolgernd lässt sich ein deutlicher Trend zum Veranstalten
von Festivals erkennen, der auch Aspekte wie die zunehmende Eventisierung beinhaltet
- …