Brachypodium distachyon: a new pathosystem to study Fusarium head blight and other Fusarium diseases of wheat

<p>Abstract</p> <p>Background</p> <p><it>Fusarium </it>species cause Fusarium head blight (FHB) and other important diseases of cereals. The causal agents produce trichothecene mycotoxins such as deoxynivalenol (DON). The dicotyledonous model species <it>Arabidopsis thaliana </it>has been used to study <it>Fusarium</it>-host interactions but it is not ideal for model-to-crop translation. <it>Brachypodium distachyon </it>(Bd) has been proposed as a new monocotyledonous model species for functional genomic studies in grass species. This study aims to assess the interaction between the most prevalent FHB-causing <it>Fusarium </it>species and Bd in order to develop and exploit Bd as a genetic model for FHB and other <it>Fusarium </it>diseases of wheat.</p> <p>Results</p> <p>The ability of <it>Fusarium graminearum </it>and <it>Fusarium culmorum </it>to infect a range of Bd tissues was examined in various bioassays which showed that both species can infect all Bd tissues examined, including intact foliar tissues. DON accumulated in infected spike tissues at levels similar to those of infected wheat spikes. Histological studies revealed details of infection, colonisation and host response and indicate that hair cells are important sites of infection. Susceptibility to <it>Fusarium </it>and DON was assessed in two Bd ecotypes and revealed variation in resistance between ecotypes.</p> <p>Conclusions</p> <p>Bd exhibits characteristics of susceptibility highly similar to those of wheat, including susceptibility to spread of disease in the spikelets. Bd is the first reported plant species to allow successful infection on intact foliar tissues by FHB-causing <it>Fusarium </it>species. DON appears to function as a virulence factor in Bd as it does in wheat. Bd is proposed as a valuable model for undertaking studies of Fusarium head blight and other <it>Fusarium </it>diseases of wheat.</p

The effect of transition type in multi-view 360 media

360-degree images and video have become extremely popular formats for immersive displays, due in large part to the technical ease of content production. While many experiences use a single camera viewpoint, an increasing number of experiences use multiple camera locations. In such multi-view 360-degree media (MV360M) systems, a visual effect is required when the user transitions from one camera location to another. This effect can take several forms, such as a cut or an image-based warp, and the choice of effect may impact many aspects of the experience, including issues related to enjoyment and scene understanding. To investigate the effect of transition types on immersive MV360M experiences, a repeated-measures experiment was conducted with 31 participants. Wearing a head-mounted display, participants explored four static scenes, for which multiple 360-degree images and a reconstructed 3D model were available. Three transition types were examined: teleport, a linear move through a 3D model of the scene, and an image-based transition using a Mobius transformation. The metrics investigated included spatial awareness, users’ movement profiles, transition preference and the subjective feeling of moving through the space. Results indicate that there was no significant difference between transition types in terms of spatial awareness, while significant differences were found for users’ movement profiles, with participants taking 1.6 seconds longer to select their next location following a teleport transition. The model and Mobius transitions were significantly better in terms of creating the feeling of moving through the space. Preference was also significantly different, with model and teleport transitions being preferred over Mobius transitions. Our results indicate that trade-offs between transitions will require content creators to think carefully about what aspects they consider to be most important when producing MV360M experiences

Investigating the perceived strengths and limitations of Free-Viewpoint Video (FVV)

Free-viewpoint video (FVV) is a type of immersive content in which a character performance is filmed using an array of cameras and processed into a video-textured, animated 3D mesh. Although FVV content has a unique set of properties that differentiates it from other immersive media types, relatively little work explores the user experience of such content. As a preliminary investigation, we adopted an open-ended, qualitative approach to investigate these issues. Semi-structured interviews were conducted with six immersive content experts, exploring the perceived strengths and limitations of FVV as a content type. These interviews were analyzed using inductive thematic analysis. We identified five themes during our analysis: they don't look real, but that's okay; they can really move; they don't connect with me; encounter, legacy, and truth; no technology is an island. Our analysis reveals a wide range of future research directions and provides insight into which areas may produce the most benefit in relation to the user experience. We discuss, for example, the potential impact of difficulties in supporting user engagement, aspects related to visual quality such as the importance of responding realistically to environment lighting, and tensions between visual and behavioral quality. The analysis also highlights the complex interplay of factors related to the content itself, such as performance style and the use of creative production techniques to reduce the impact of potential limitations

Improving Free-Viewpoint Video content production using RGB-camera-based skeletal tracking

Free-Viewpoint Video (FVV) is a type of volumetric content in which an animated, video-textured 3D mesh of a character performance is constructed using data from an array of cameras. Previous work has demonstrated excellent results when creating motion graphs from FVV content, but these techniques are often prohibitively expensive in practice. We propose the use of skeletons to identify cut points between FVV clips, allowing a minimal set of frames to be processed into a 3D mesh. While our method performed with 2.8% poorer accuracy than the state-of-the-art for our synthetic dataset, cost and processing time requirements are dramatically reduced

Object removal in panoramic media

Due in large part to new consumer virtual reality systems, panoramic media is an increasingly popular image and video format. While the capture of panoramic media is well understood, editing still poses many challenges. In this paper we explore object removal in 360 images. First, a method is proposed in which field-of-view expansion using retargeting techniques is combined with Graphcut Textures to remove objects near the equator of the viewing sphere. Several extensions and refinements are proposed to improve this technique, including how it can be extended to removing objects anywhere on the viewing sphere. Secondly, inpainting in 360 images is examined, with an exploration of how the choice of projection affects the inpainting result. Finally, the latter technique is shown to work for video in certain situations

Perception of volumetric characters' eye-gaze direction in head-mounted displays

Volumetric capture allows the creation of near-video-quality content that can be explored with six degrees of freedom. Due to limitations in these experiences, such as the content being fixed at the point of filming, an understanding of eye-gaze awareness is critical. A repeated-measures experiment was conducted that explored users’ ability to evaluate where a volumetrically captured avatar (VCA) was looking. Wearing one of two head-mounted displays (HMDs), 36 participants rotated a VCA to look at a target. The HMD resolution, target position, and VCA’s eye-gaze direction were varied. Results did not show a difference in accuracy between HMD resolutions, while the task became significantly harder for target locations further away from the user. In contrast to real-world studies, participants consistently misjudged eye-gaze direction based on target location, but not based on the avatar’s head turn direction. Implications are discussed, as results for VCAs viewed in HMDs appear to differ from face-to-face scenarios

Biotic and Abiotic Associations with Westslope Cutthroat Trout (Oncorhynchus clarkii lewisi) in the North Fork Flathead River Basin in northwestern Montana, USA and southeastern British Columbia, CAN under current and future climate scenarios.

Westslope Cutthroat Trout (Oncorhynchus clarkii lewisi; WCT) populations are declining across much of their native range due to threats such as habitat degradation, competition with non-native species, and climate change. Understanding how habitat characteristics impact distributions of nonhybridized WCT populations throughout a relatively pristine core conservation area is needed to inform management and conservation efforts. We investigated whether abiotic (e.g., gradient) and biotic (i.e., Bull Trout – Salvelinus confluentus) variables predicted WCT presence and predicted how future stream temperature projections for the area might be expected to alter distributions. We compared logistic regression models of WCT presence throughout tributaries of the North Fork Flathead River in Montana, USA and British Columbia, CAN models using a variety of metrics (e.g., Akaike Information Criterion). WCT were widespread throughout the 293 reaches analyzed (present in 69.3% of reaches). Their presence was predicted by gradient, summer temperature, and an interaction of pool density and Bull Trout. Using this regression model and climate projections under both moderate and extreme emissions scenarios, WCT presence is predicted to increase by 13.0% and 14.1% respectively in 2075 from current distributions based on changes in temperature alone. When changes in Bull Trout distributions and temperatures are considered, WCT distributions are predicted to increase by 13.4% and 17.5% under the moderate and high emissions scenario, respectively. This conservation area is predicted to continue to serve as a WCT stronghold, if other threats can be contained

Directing versus attracting attention: exploring the effectiveness of central and peripheral cues in panoramic videos

Filmmakers of panoramic videos frequently struggle to guide attention to Regions of Interest (ROIs) due to consumers’ freedom to explore. Some researchers hypothesize that peripheral cues attract reflexive/involuntary attention whereas cues within central vision engage and direct voluntary attention. This mixed-methods study evaluated the effectiveness of using central arrows and peripheral flickers to guide and focus attention in panoramic videos. Twenty-five adults wore a head-mounted display with an eye tracker and were guided to 14 ROIs in two panoramic videos. No significant differences emerged in regard to the number of followed cues, the time taken to reach and observe ROIs, ROI-related memory and user engagement. However, participants’ gaze travelled a significantly greater distance toward ROIs within the first 500 ms after flicker-onsets compared to arrow-onsets. Nevertheless, most users preferred the arrow and perceived it as significantly more rewarding than the flicker. The findings imply that traditional attention paradigms are not entirely applicable to panoramic videos, as peripheral cues appear to engage both involuntary and voluntary attention. Theoretical and practical implications as well as limitations are discussed

Threaded Rings that Swim in Excitable Media

Cardiac tissue and the Belousov-Zhabotinsky reaction provide two notable examples of excitable media that support scroll waves, in which a filament core is the source of spiral waves of excitation. Here we consider a novel topological configuration in which a closed filament loop, known as a scroll ring, is threaded by a pair of counterrotating filaments that are perpendicular to the plane of the ring and end on the boundary of a thin medium. We simulate the dynamics of this threaded ring (thring) in the photosensitive Belousov-Zhabotinsky excitable medium, using the modified Oregonator reaction-diffusion equations. These computations reveal that the threading topology induces an exotic motion in which the thring swims in the plane of the ring. We propose a light templating protocol to create a thring in the photosensitive Belousov-Zhabotinsky medium and provide experimental confirmation that this protocol indeed yields a thrin