Olfactory associative learning in Caenorhabditis elegans is impaired in lrn-1 and lrn-2 mutants.

The C. elegans mutants, lrn-1 and lrn-2, are impaired in associative learning using conditioned taste cues. Both mutants are defective in associative learning about appetitive and aversive events, indicating that lrn-1 and lrn-2 exert effects across motivational boundaries. In a new olfactory associative learning paradigm, in which wild type worms learn to avoid a previously attractive diacetyl odor after it has been paired with an aversive acetic acid solution, lrn-1 and lrn-2 are impaired. Although defective in associative learning using a conditioned olfactory cue, nonassociative learning (habituation and dishabituation) using this same olfactory cue is unaffected. The discovery that lrn-1 and lrn-2 are defective in associative learning with both taste and olfactory cues may suggest that associative learning in different sensory modalities converges on a common genetic pathway in C. elegans that is subserved by lrn-1 and lrn-2. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thermal polymerization of thiol–ene network‐forming systems

The thermal polymerization of a tetrafunctional thiol (PETMP) and divinyl ether (TEGDVE) was monitored by temperature‐ramping differential scanning calorimetry (DSC) and the effects of inhibitor type and concentration, oxygen inhibition and initiator type were studied. The incorporation of inhibitors was required to produce a stable system at room temperature. Butylated hydroxytoluene (BHT) inhibited polymerization at low temperatures, but was inefficient at high temperatures and polymerization rates, and hence BHT is an ideal stabilizer. In contrast, a nitroxide inhibitor (NO‐67) was a very effective inhibitor and no polymerization occurred until all of the nitroxide was depleted. The presence of oxygen retarded the onset of polymerization but did not change the final conversion significantly. Polymerization with initiators having higher half‐life temperatures shifted the DSC peak to higher temperature because the rate of initiator decomposition and thus initiation was slower. Rheological investigations of the cure at different temperatures revealed that the gel time decreased significantly with increasing cure temperature, and the calculated apparent activation energy for PETMP/TEGDVE was 54 kJ mol^?1. Dynamical mechanical thermal analysis of the cured material was undertaken and frequency‐superposed results revealed that the glass transition region of PETMP/TEGDVE/azobisisobutyronitrile was much narrower than that of free‐radically cured dimethacrylate, but was similar to that of an epoxy resin cured with an aromatic diamine. This behaviour could be attributed to PETMP/TEGDVE network homogeneity, or to the less constrained crosslinks in the PETMP/TEGDVE network. Copyright © 2007 Society of Chemical Industry     

Wavelet based local tomographic image using terahertz techniques

Terahertz computed tomography has been developed based on coherent THz detection and filtered back projection (FBP) algorithms, which allows the global imaging of the internal structure and extraction of the frequency dependent properties. It offers a promising approach for achieving non-invasive inspection of solid materials. However, with traditional CT techniques, i.e. FBP algorithms, full exposure data are needed for inverting the Radon transform to produce cross sectional images. This remains true even if the region of interest is a small subset of the entire image. For time-domain terahertz measurements, the requirement for full exposure data is impractical due to the slow measurement process. This paper explores time domain reconstruction of terahertz measurements by applying wavelet-based filtered back projection algorithms for recovery of a local area of interest from terahertz measurements within its vicinity, and thus improves the feasibility of using terahertz imaging to detect defects in solid materials and diagnose disease states for clinical practise, to name a few applications.     

Reading pseudohomophones: Implications for models of pronunciation assembly and the locus of word-frequency effects in naming.

Pronunciation performance under speeded conditions was examined for various kinds of letter strings, including pseudohomophones (e.g., TRAX), their real word counterparts (e.g., TRACKS), and a set of nonword controls (e.g., PRAX). Experiment 1 yielded a pronunciation advantage for the pseudohomophones relative to the controls, which was largest among items having few or no orthographic neighbors. Experiment 2 ruled out an account of the pseudohomophone advantage based on differences between pseudohomophones and controls in initial phonemes. Experiment 3 established the existence of a large frequency effect on pronunciation of the base words themselves. These results suggest that whole word representations in the phonological output lexicon are consulted in the course of assembling a pronunciation and that representations in a phonological output lexicon are insensitive to word frequency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling missile propellant fires in shipboard compartments

There are a number of shipboard situations where the unintentional burning of missile propellant is a concern. Full-scale test programs have investigated the phenomena associated with propellant fires. An existing computer fire model, FAST, was modified to account for fire phenomena specific to missile propellant combustion. The modified computer program and the developed missile propellant burning rate algorithm were exercised in blind predictions of full-scale tests. Comparisons between the blind predictions and the test data are presented.     

Ontology-driven hypothesis generation to explain anomalous patient responses to treatment

Within the medical domain there are clear expectations as to how a patient should respond to treatments administered. When these responses are not observed it can be challenging for clinicians to understand the anomalous responses. The work reported here describes a tool which can detect anomalous patient responses to treatment and further suggest hypotheses to explain the anomaly. In order to develop this tool, we have undertaken a study to determine how Intensive Care Unit (ICU) clinicians identify anomalous patient responses; we then asked further clinicians to provide potential explanations for such anomalies. The high level reasoning deployed by the clinicians has been captured and generalised to form the procedural component of the ontology-driven tool. An evaluation has shown that the tool successfully reproduced the clinician’s hypotheses in the majority of cases. Finally, the paper concludes by describing planned extensions to this work.     

Integration of chaos theory and mathematical models in building simulation: Part I: Literature review

Current mathematical models in building research have been limited in most studies to linear dynamics systems. A literature review of past studies investigating chaos theory approaches in building simulation models suggests that as a basis chaos model is valid and can handle the increasingly complexity of building systems that have dynamic interactions among all the distributed and hierarchical systems on the one hand, and the environment and occupants on the other. The review also identifies the paucity of literature and the need for a suitable methodology of linking chaos theory to mathematical models in building design and management studies. This study is broadly divided into two parts and presented in two companion papers. Part (I) reviews the current state of the chaos theory models as a starting point for establishing theories that can be effectively applied to building simulation models. Part (II) develops conceptual frameworks that approach current model methodologies from the theoretical perspective provided by chaos theory, with a focus on the key concepts and their potential to help to better understand the nonlinear dynamic nature of built environment systems. Case studies are also presented which demonstrate the potential usefulness of chaos theory driven models in a wide variety of leading areas of building research. This study distills the fundamental properties and the most relevant characteristics of chaos theory essential to building simulation scientists, initiates a dialogue and builds bridges between scientists and engineers, and stimulates future research about a wide range of issues on building environmental systems.     

Reading aloud: Qualitative differences in the relation between stimulus quality and word frequency as a function of context.

Virtually all theories of visual word recognition assume (typically implicitly) that when a pathway is used, processing within that pathway always unfolds in the same way. This view is challenged by the observation that simple variations in list composition are associated with qualitative changes in performance. The present experiments demonstrate that when reading aloud, the joint effects of stimulus quality and word frequency on response time are driven by the presence/absence of nonwords in the list. Interacting effects of these factors are seen when only words appear in the experiment, whereas additive effects are seen when words and nonwords are randomly intermixed. One way to explain these and other data appeals to the distinction between cascaded processing (or interactive activation) on the one hand versus a thresholded mode of processing on the other, with contextual factors determining which mode of processing dominates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Health and illness: the definition of the World Health Organization

Ethik in der Medizin -