Exploring the use of Controlled English for communication with ACT-R agents

Research is being undertaken into sense-making by collaborative agents, based upon a cognitive framework of human behaviour, ACT-R, together with communication between the agents. We explore the use of Controlled English for this purpos

Effect of Tactile Feedback on Performance

Humans interact with their environment by obtaining information from various modalities of sensing. These various modalities of sensing combine to facilitate manipulation and interaction with objects and the environment. The way humans interact with computers mirrors this environmental interaction with the absence of feedback from the tactile channel. The majority of computer operation is completed visually because currently, the primary feedback humans receive from computers is through the eyes. This strong dependence on the visual modality can cause visual fatigue and fixation on displays, resulting in errors and a decrease in performance. Distributing tasks and information across sensory modalities could possibly solve this problem. This study added tactile feedback to the human computer interface through vibration of a mouse to more accurately reflect a human\u27s multi-sensory interaction with their environment. This investigation used time off target to measure performance in a pursuit-tracking task. The independent variables were type of feedback with two levels, (i.e., tactile feedback vs no tactile feedback) and speed of target at three different levels, (i.e., slow, medium, and fast). Tactile feedback improved pursuit-tracking performance by 6%. Significant main effects where found for both the speed and feedback factors, but no significant interaction between speed and feedback was obtained. This improvement in performance was consistent with previous research, and lends further support to the advantages multimodal feedback may have to offer man-machine interfaces

Earth-atmosphere evolution based on the new determination of Devonian atmosphere Ar isotopic composition

The isotopic composition of the noble gases, in particular Ar, in samples of ancient atmosphere trapped in rocks and minerals provides the strongest constraints on the timing and rate of Earth atmosphere formation by degassing of the Earth's interior. We have re-measured the isotopic composition of argon in the Rhynie chert from northeast Scotland using a high precision mass spectrometer in an effort to provide constraints on the composition of Devonian atmosphere. Irradiated chert samples yield 40Ar/36Ar ratios that are often below the modern atmosphere value. The data define a 40Ar/36Ar value of 289.5±0.4 at K/36Ar = 0. Similarly low 40Ar/36Ar are measured in un-irradiated chert samples. The simplest explanation for the low 40Ar/36Ar is the preservation of Devonian atmosphere-derived Ar in the chert, with the intercept value in 40Ar–39Ar–36Ar space representing an upper limit. In this case the Earth's atmosphere has accumulated only 3% (5.1±0.4×1016 mol) of the total 40Ar inventory since the Devonian. The average accumulation rate of 1.27±0.09×108 mol40Ar/yr overlaps the rate over the last 800 kyr. This implies that there has been no resolvable temporal change in the outgassing rate of the Earth since the mid-Palaeozoic despite the likely episodicity of Ar degassing from the continental crust. Incorporating the new Devonian atmosphere 40Ar/36Ar into the Earth degassing model of Pujol et al. (2013) provides the most precise constraints on atmosphere formation so far. The atmosphere formed in the first ∼100 Ma after initial accretion during a catastrophic degassing episode. A significant volume of 40Ar did not start to accumulate in the atmosphere until after 4 Ga which implies that stable K-rich continental crust did not develop until this time

A functional link between the actin cytoskeleton and lipid rafts during budding of filamentous influenza virions

AbstractMorphogenesis of influenza virus is a poorly understood process that produces two types of enveloped virion: ∼100-nm spheres and similar diameter filaments that reach 20 μm in length. Spherical particles assemble at plasma membrane lipid rafts in a process independent of microfilaments. The budding site of filamentous virions is hitherto uncharacterised but their formation involves the actin cytoskeleton. We confirm microfilament involvement in filamentous budding and show that after disruption of cortical actin by jasplakinolide, HA, NP, and M1 redistributed around β-actin clusters to form novel annular membrane structures. HA in filamentous virions and jasplakinolide-induced annuli was detergent insoluble at 4°C. Furthermore, in both cases HA partitioned into low buoyant density detergent-insoluble glycolipid domains, indicating that filamentous virions and annuli contain reorganised lipid rafts. We propose that the actin cytoskeleton is required to maintain the correct organisation of lipid rafts for incorporation into budding viral filaments

Reverse osmosis brine concentration using falling film freeze crystallisation technology: a pilot-scale study

The reverse osmosis (RO) desalination process has increasingly been utilized with aim of producing drinking water from different marginal sources of water such as seawater, and brackish ground and surface water, due to water scarcity. Unfortunately, desalination applications are limited by the brine disposal challenges including the adverse impact of brine on the surrounding environment. Therefore, this paper is focused on the technical evaluation of falling film freeze crystallization (FFFC) technology for treating and concentrating RO brine. An industrial pilot plant using the FFFC process was tested and assessed for concentrating RO brine in this study. The experimental results showed that the crystallization experiments using a feed stage (without the sweating process) and at the operating end-point heat transfer medium (HTM) temperature of –6°C, achieved a salt rejection ratio and water recovery ratio of 56.6% and 49.8% respectively. Whereas at the endpoint HTM temperature of –24°C, the salt rejection ratio and water recovery ratios were 24.5% and 84.6% respectively. The multi-stage process experiments using feed and rectification stages (without the sweating process) achieved a salt rejection and product water recovery ratio of 46.89% and 64.24% respectively. By using a multi-stage process including feed, rectification, and stripping stages (with the sweating process), the salt rejection and product water recovery ratio reached 70.68% and 50.15% respectively. In general, the results showed that the FFFC technology, using a single freezing stage and without the sweating process, would be an ideal treatment system for concentrating RO brine and to produce saline water to near seawater quality that can be used directly as feed water for a RO plant. The research proved that the investigated FFFC process can be considered as a great solution available for brine concentration and as an alternative for reducing the environmental impact of the large volume of waste streams from coastal and inland desalination plants

Comparative genomics of Shiga toxin encoding bacteriophages

Background Stx bacteriophages are responsible for driving the dissemination of Stx toxin genes (stx) across their bacterial host range. Lysogens carrying Stx phages can cause severe, lifethreatening disease and Stx toxin is an integral virulence factor. The Stx-bacteriophage vB_EcoP-24B, commonly referred to as 24B, is capable of multiply infecting a single bacterial host cell at a high frequency, with secondary infection increasing the rate at which subsequent bacteriophage infections can occur. This is biologically unusual, therefore determining the genomic content and context of 24B compared to other lambdoid Stx phages is important to understanding the factors controlling this phenomenon and determining whether they occur in other Stx phages. Results The genome of the Stx2 encoding phage, 24B was sequenced and annotated. The genomic organisation and general features are similar to other sequenced Stx bacteriophages induced from Enterohaemorrhagic Escherichia coli (EHEC), however 24B possesses significant regions of heterogeneity, with implications for phage biology and behaviour. The 24B genome was compared to other sequenced Stx phages and the archetypal lambdoid phage, lambda, using the Circos genome comparison tool and a PCR-based multi-loci comparison system. Conclusions The data support the hypothesis that Stx phages are mosaic, and recombination events between the host, phages and their remnants within the same infected bacterial cell will continue to drive the evolution of Stx phage variants and the subsequent dissemination of shigatoxigenic potentia

Enhancement of reliability in condition monitoring techniques in wind turbines

The majority of electrical failures in wind turbines occur in the semiconductor components (IGBTs) of converters. To increase reliability and decrease the maintenance costs associated with this component, several health-monitoring methods have been proposed in the literature. Many laboratory-based tests have been conducted to detect the failure mechanisms of the IGBT in their early stages through monitoring the variations of thermo-sensitive electrical parameters. The methods are generally proposed and validated with a single-phase converter with an air-cored inductive or resistive load. However, limited work has been carried out considering limitations associated with measurement and processing of these parameters in a three-phase converter. Furthermore, looking at just variations of the module junction temperature will most likely lead to unreliable health monitoring as different failure mechanisms have their own individual effects on temperature variations of some, or all, of the electrical parameters. A reliable health monitoring system is necessary to determine whether the temperature variations are due to the presence of a premature failure or from normal converter operation. To address this issue, a temperature measurement approach should be independent from the failure mechanisms. In this paper, temperature is estimated by monitoring an electrical parameter particularly affected by different failure types. Early bond wire lift-off is detected by another electrical parameter that is sensitive to the progress of the failure. Considering two separate electrical parameters, one for estimation of temperature (switching off time) and another to detect the premature bond wire lift-off (collector emitter on-state voltage) enhance the reliability of an IGBT could increase the accuracy of the temperature estimation as well as premature failure detection