718 research outputs found
Stable Determination of the Electromagnetic Coefficients by Boundary Measurements
The goal of this paper is to prove a stable determination of the coefficients
for the time-harmonic Maxwell equations, in a Lipschitz domain, by boundary
measurements
Alternative display and interaction devices
While virtual environment systems are typically thought to consist of a head mounted display and a flex-sensing glove, alternative peripheral devices are beginning to be developed in response to application requirements. Three such alternatives are discussed: fingertip sensing gloves, fixed stereoscopic viewers, and counterbalanced head mounted displays. A subset of commercial examples that highlight each alternative is presented as well as a brief discussion of interesting engineering and implementation issues
Distribution and abundance of fish and crayfish in a Waikato stream in relation to basin area
The aim of this study was to relate the longitudinal distribution of fish and crayfish to increasing basin area and physical site characteristics in the Mangaotama Stream, Waikato region, North Island, New Zealand. Fish and crayfish were captured with two-pass removal electroshocking at 11 sites located in hill-country with pasture, native forest, and mixed land uses within the 21.6 km2 basin. Number of fish species and lineal biomass of fish increased with increasing basin area, but barriers to upstream fish migration also influenced fish distribution; only climbing and non-migratory species were present above a series of small waterfalls. Fish biomass increased in direct proportion to stream width, suggesting that fish used much of the available channel, and stream width was closely related to basin area. Conversely, the abundance of crayfish was related to the amount of edge habitat, and therefore crayfish did not increase in abundance as basin area increased. Densities of all fish species combined ranged from 17 to 459 fish 100 m-2, and biomass ranged from 14 to 206 g m-2. Eels dominated the fish assemblages, comprising 85-100% of the total biomass; longfinned eels the majority of the biomass at most sites. Despite the open access of the lower sites to introduced brown trout, native species dominated all the fish communities sampled
The role of mindfulness in distress and quality of life for men with advanced prostate cancer.
OBJECTIVE: To examine the extent to which mindfulness skills influence psychological distress and health-related quality of life (HRQOL) in men with metastatic or castration-resistant biochemical progression of prostate cancer. PATIENTS AND METHODS: A cross-sectional survey of 190 men (46 % response; mean age 71 years, SD = 8.7, range 40-91 years) with advanced prostate cancer, assessed psychological and cancer-specific distress, HRQOL. Mindfulness skills were assessed as potential predictors of adjustment outcomes. RESULTS: Overall, 39 % of men reported high psychological distress. One third had accessed psychological support previously although only 10 % were under current psychological care. One quarter had accessed a prostate cancer support group in the past six months. Higher HRQOL and lower cancer-specific and global psychological distress were related to non-judging of inner experience (p < 0.001). Higher HRQOL and lower psychological distress were related to acting with awareness (p < 0.001). Lower distress was also related to higher non-reactivity to inner experience and a lower level of observing (p < 0.05). CONCLUSIONS: Men with advanced prostate cancer are at risk of poor psychological outcomes. Psychological flexibility may be a promising target for interventions to improve adjustment outcomes in this patient group. CLINICAL TRIAL REGISTRY: Trial Registration: ACTRN12612000306819
Phylogenetic-based propagation of functional annotations within the Gene Ontology consortium
The goal of the Gene Ontology (GO) project is to provide a uniform way to describe the functions of gene products from organisms across all kingdoms of life and thereby enable analysis of genomic data. Protein annotations are either based on experiments or predicted from protein sequences. Since most sequences have not been experimentally characterized, most available annotations need to be based on predictions. To make as accurate inferences as possible, the GO Consortium's Reference Genome Project is using an explicit evolutionary framework to infer annotations of proteins from a broad set of genomes from experimental annotations in a semi-automated manner. Most components in the pipeline, such as selection of sequences, building multiple sequence alignments and phylogenetic trees, retrieving experimental annotations and depositing inferred annotations, are fully automated. However, the most crucial step in our pipeline relies on software-assisted curation by an expert biologist. This curation tool, Phylogenetic Annotation and INference Tool (PAINT) helps curators to infer annotations among members of a protein family. PAINT allows curators to make precise assertions as to when functions were gained and lost during evolution and record the evidence (e.g. experimentally supported GO annotations and phylogenetic information including orthology) for those assertions. In this article, we describe how we use PAINT to infer protein function in a phylogenetic context with emphasis on its strengths, limitations and guidelines. We also discuss specific examples showing how PAINT annotations compare with those generated by other highly used homology-based methods
Fluctuations and differential contraction during regeneration of Hydra vulgaris tissue toroids
We studied regenerating bilayered tissue toroids dissected from Hydra
vulgaris polyps and relate our macroscopic observations to the dynamics of
force-generating mesoscopic cytoskeletal structures. Tissue fragments undergo a
specific toroid-spheroid folding process leading to complete regeneration
towards a new organism. The time scale of folding is too fast for biochemical
signalling or morphogenetic gradients which forced us to assume purely
mechanical self-organization. The initial pattern selection dynamics was
studied by embedding toroids into hydro-gels allowing us to observe the
deformation modes over longer periods of time. We found increasing mechanical
fluctuations which break the toroidal symmetry and discuss the evolution of
their power spectra for various gel stiffnesses. Our observations are related
to single cell studies which explain the mechanical feasibility of the folding
process. In addition, we observed switching of cells from a tissue bound to a
migrating state after folding failure as well as in tissue injury.
We found a supra-cellular actin ring assembled along the toroid's inner edge.
Its contraction can lead to the observed folding dynamics as we could confirm
by finite element simulations. This actin ring in the inner cell layer is
assembled by myosin- driven length fluctuations of supra-cellular
{\alpha}-actin structures (myonemes) in the outer cell-layer.Comment: 19 pages and 8 figures, submitted to New Journal of Physic
Localised hydrogen peroxide sensing for reproductive health
Session 10 - Chemical Sensors and Biosensors IIThe production of reactive oxygen species (ROS) is known to affect the developmental competence of embryos. Hydrogen peroxide (H₂O₂) an important reactive oxygen species, is also known to causes DNA damage and defective sperm function. Current techniques require incubating a developing embryo with an organic fluorophore which is potentially hazardous for the embryo. What we need is a localised ROS sensor which does not require fluorophores in solution and hence will allow continuous monitoring of H₂O₂ production without adversely affect the development of the embryo. Here we report studies on such a fibre-based sensor for the detection of H₂O₂ that uses a surface-bound aryl boronate fluorophore carboxyperoxyfluor-1(CPF1). Optical fibres present a unique platform due to desirable characteristics as dip sensors in biological solutions. Attempts to functionalise the fibre tips using polyelectrolyte layers and (3-aminopropyl)triethoxysilane (APTES) coatings resulted in a limited signal and poor fluorescent response to H₂O₂ due to a low tip surface density of the fluorophore. To increase the surface density, CPF1 was integrated into a polymer matrix formed on the fibre tip by a UV-catalysed polymerisation process of acrylamide onto a methacrylate silane layer. The polyacrylamide containing CPF1 gave a much higher surface density than previous surface attachment methods and the sensor was found to effectively detect H₂O₂. Using this method, biologically relevant concentrations of H₂O₂ were detected, enabling remote sensing studies into ROS releases from embryos throughout early development.Malcolm S Purdey, Erik P Schartner, Melanie L Sutton-McDowall, Lesley J Ritter, Jeremy G Thompson, Tanya M Monro, and Andrew D Abel
Induced innovation in energy technologies and systems: a review of evidence and potential implications for CO2 mitigation
We conduct a systematic, interdisciplinary review of empirical literature assessing evidence on induced innovation in energy and related technologies. We explore links between demand-drivers (both market-wide and targeted); indicators of innovation (principally, patents); and outcomes (cost reduction, efficiency, and multi-sector/macro consequences). We build on existing reviews in different fields and assess over 200 papers containing original data analysis. Papers linking drivers to patents, and indicators of cumulative capacity to cost reductions (experience curves), dominate the literature. The former does not directly link patents to outcomes; the latter does not directly test for the causal impact of on cost reductions). Diverse other literatures provide additional evidence concerning the links between deployment, innovation activities, and outcomes. We derive three main conclusions. (1) Demand-pull forces enhance patenting; econometric studies find positive impacts in industry, electricity and transport sectors in all but a few specific cases. This applies to all drivers - general energy prices, carbon prices, and targeted interventions that build markets. (2) Technology costs decline with cumulative investment for almost every technology studied across all time periods, when controlled for other factors. Numerous lines of evidence point to dominant causality from at-scale deployment (prior to self-sustaining diffusion) to cost reduction in this relationship. (3) Overall Innovation is cumulative, multi-faceted, and self-reinforcing in its direction (path-dependent). We conclude with brief observations on implications for modeling and policy. In interpreting these results, we suggest distinguishing the economics of active deployment, from more passive diffusion processes, and draw the following implications. There is a role for policy diversity and experimentation, with evaluation of potential gains from innovation in the broadest sense. Consequently, endogenising innovation in large-scale models is important for deriving policy-relevant conclusions. Finally, seeking to relate quantitative economic evaluation to the qualitative socio-technical transitions literatures could be a fruitful area for future research
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Combining quantitative and qualitative survey work. Methodological framework, practical issues, and case studies
This document is an output of the DFID funded research project R7033 "Methodological Framework for Integrating Qualitative and Quantitative Approaches for Socio-Economic Survey Work". The project's main objective was to improve survey methodologies used in the natural resources sector, leading in turn to improved quality of information required for decision-making at the various stages of natural resources programmes and projects. The project, which was jointly implemented by the Natural Resources Institute and the Statistical Services Centre, attempted to bridge the gap between informal I qualitative methods on the one hand and formal I quantitative ones on the other. The document is presented in the form of a manual, allowing the user to read each of its parts and sections independently of each other. Nevertheless, cross references indicate links to other parts of the document where appropriate. Part I provides a methodological framework, which will also be available as a Best-Practice Guideline published by the Natural Resources Systems Programme of DFID. Part 11, which contains six theme papers, looks into a number of practical issues encountered when combining quantitative and qualitative survey techniques. And finally, in Part III case studies are used to demonstrate how the two approaches can be integrated in survey work and experiments related to the natural resources sector. The framework document, theme papers and case studies have been produced between 1998 and 2000
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