27 research outputs found

    Weighted Automata and Expressions over Pre-Rational Monoids

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    The Kleene theorem establishes a fundamental link between automata and expressions over the free monoid. Numerous generalisations of this result exist in the literature; on one hand, lifting this result to a weighted setting has been widely studied. On the other hand, beyond the free monoid, different monoids can be considered: for instance, two-way automata, and even tree-walking automata, can be described by expressions using the free inverse monoid. In the present work, we aim at combining both research directions and consider weighted extensions of automata and expressions over a class of monoids that we call pre-rational, generalising both the free inverse monoid and graded monoids. The presence of idempotent elements in these pre-rational monoids leads in the weighted setting to consider infinite sums. To handle such sums, we will have to restrict ourselves to rationally additive semirings. Our main result is thus a generalisation of the Kleene theorem for pre-rational monoids and rationally additive semirings. As a corollary, we obtain a class of expressions equivalent to weighted two-way automata, as well as one for tree-walking automata

    Drawing to Remember: External Support of Older Adults’ Eyewitness Performance

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    Although healthy aging is accompanied by a general decline in memory functioning, environmental support at retrieval can improve older adults’ (+65 years) episodic remembering. Despite those over the age of 65years representing a growing proportion of the population, few environmental retrieval support methods have been empirically evaluated for use with older witnesses and victims of crime. Here, the efficacy of a novel retrieval technique, the Sketch Mental Reinstatement of Context, is compared with a standard Mental Reinstatement of Context and a no support control (Control). Fifty-one participants witnessed an unexpected live event, and 48 hours later were interviewed using one of three aforementioned techniques. In line with predictions emanating from cognitive theories of aging and the environmental support hypothesis, participants in the Sketch Mental Reinstatement of Context condition recalled significantly more correct information and fewer inaccurate items. The Sketch Mental Reinstatement of Context technique appears to scaffold memory retrieval in an age-appropriate manner during a post-event interview, possibly by encouraging more effortful retrieval and reducing dual-task load. As such, this procedure offers an effective alternative to current approaches, adding to the toolbox of techniques available to forensic and other interviewers

    ‘‘One needs to be very brave to stand all that’’: Cycling, rational dress and the struggle for citizenship in late nineteenth century Britain

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    The article discusses changing ideas around citizenship through an analysis of first person accounts of women cyclists in Rational Dress in late nineteenth century Britain. A close reading of personal correspondence provides a sense of how it felt to cycle while dressed in new mobility costumes, such as bloomers, in urban and suburban English landscapes. Such attired and independently mobile women affirmed or unsettled onlooker’s understandings of how middle and upper class women should look and act in public. Some viewers subjected them to verbal and often physical assault. Others, in awe of their socio-technical sophistication were more supportive. Taking a ’bloomer point of view’ provides a unique socio-material way of gaining a deeper understanding of what enabled and also inhibited women’s claims to citizenship and freedom of movement, especially at a time when women were not citizens in a legal sense. I argue that through these richly described accounts we gain insightful glimpses into how individual sensory, embodied and political experiences collectively illuminate the becoming of ’citizen’ as it relates to mobility, gender and landscape

    No evidence against Sketch Reinstatement of context, verbal labels or the use of registered intermediaries for children with Autism Spectrum Disorder: response to Henry et al. (2017)

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    Recently, Henry et al. (2017) found no evidence for the use of Verbal labels, Sketch Reinstatement of Context and Registered Intermediaries by forensic practitioners when interviewing children with a diagnosis of Autism Spectrum Disorder. We consider their claims, noting the limited ecological validity of the experimental paradigm, the impacts of repeated interviewing where retrieval support is not provided at first retrieval, question the interviewer/intermediary training and their population relevant experience, and comment on the suppression of population variances. We submit that rejecting these techniques on the basis of this study is completely unwarranted and potentially damaging, particularly if used in legal proceedings to undermine the value of testimony from children with ASD, who continually struggle to gain access to justice

    Probenecid Inhibits the Human Bitter Taste Receptor TAS2R16 and Suppresses Bitter Perception of Salicin

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    Bitter taste stimuli are detected by a diverse family of G protein-coupled receptors (GPCRs) expressed in gustatory cells. Each bitter taste receptor (TAS2R) responds to an array of compounds, many of which are toxic and can be found in nature. For example, human TAS2R16 (hTAS2R16) responds to β-glucosides such as salicin, and hTAS2R38 responds to thiourea-containing molecules such as glucosinolates and phenylthiocarbamide (PTC). While many substances are known to activate TAS2Rs, only one inhibitor that specifically blocks bitter receptor activation has been described. Here, we describe a new inhibitor of bitter taste receptors, p-(dipropylsulfamoyl)benzoic acid (probenecid), that acts on a subset of TAS2Rs and inhibits through a novel, allosteric mechanism of action. Probenecid is an FDA-approved inhibitor of the Multidrug Resistance Protein 1 (MRP1) transporter and is clinically used to treat gout in humans. Probenecid is also commonly used to enhance cellular signals in GPCR calcium mobilization assays. We show that probenecid specifically inhibits the cellular response mediated by the bitter taste receptor hTAS2R16 and provide molecular and pharmacological evidence for direct interaction with this GPCR using a non-competitive (allosteric) mechanism. Through a comprehensive analysis of hTAS2R16 point mutants, we define amino acid residues involved in the probenecid interaction that result in decreased sensitivity to probenecid while maintaining normal responses to salicin. Probenecid inhibits hTAS2R16, hTAS2R38, and hTAS2R43, but does not inhibit the bitter receptor hTAS2R31 or non-TAS2R GPCRs. Additionally, structurally unrelated MRP1 inhibitors, such as indomethacin, fail to inhibit hTAS2R16 function. Finally, we demonstrate that the inhibitory activity of probenecid in cellular experiments translates to inhibition of bitter taste perception of salicin in humans. This work identifies probenecid as a pharmacological tool for understanding the cell biology of bitter taste and as a lead for the development of broad specificity bitter blockers to improve nutrition and medical compliance

    Seismological structure of the Carpathian-Pannonian region of central Europe

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    The extensional Pannonian Basin is set within the convergent arc of the Alpine-Carpathian mountain system in central Europe. Various models have been proposed as mechanisms to drive extension within this collisional setting. As part of the Carpathian Basins Project(CBP), a temporary network of 56 broadband seismometers was deployed. With a further 44 permanent broadband seismometers, tomographic inversion of P and S-wave relative arrival-time residuals from teleseismic earthquakes, reveal the velocity structure of the mantle to a depth of 850 km throughout the Carpathian-Pannonian region. The tomographic models reduce the P-wave rms residual by 71% from 0.446 s to 0.130 s, and the S-wave rms residual by 59% from 1.513 s to 0.624 s. The effect of applying a deterministic crustal correction on the relative arrival-time residuals is tested using a crustal velocity model derived from previous crustal seismic experiments, but I show that the use of a station term parameter in the inversion provides a robust method of correcting for near-surface velocity variations in this experiment. At shallow sub-lithospheric depths several localised slower regions are imaged, which correlate with extensional depocentres and regional volcanics, and are interpreted as upwelling asthenosphere. Beneath the Eastern Alps, I image a high velocity structure, which continues east beneath the Pannonian Basin with depth and into the mantle transition zone (MTZ). The fast anomaly in the MTZ is distributed laterally as far as the Carpathians, the Dinarides and the Eastern Alps. The high velocity mantle material linking the structure beneath the Pannonian Basin with the Eastern Alps indicates a once continuous continental collision zone. Eastward extrusion from the Adria collision and detachment of the continental lithosphere beneath the Carpathians resulted in asthenospheric upwelling, which may have provided the driving force for extension of the Pannonian Basin

    Environmental Immersion’s Influence on Hedonics, Perceived Appropriateness, and Willingness to Pay in Alcoholic Beverages

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    The eating experience is multimodal. As we consume a dish, we perceive much more than that which initially activates the senses, including influences from our surroundings. Foods sampled in experimental settings are largely evaluated within a sensory booth, an environment designed to be devoid of such external or non-standardized stimuli, so that participants can focus solely on the sample itself. In natural experiences, we rarely consume food in such isolation—context is actually key to many dining experiences and can have an integral role in how we perceive the foods we eat. Using virtual reality to artificially provide this context, we tested how the setting in which a beverage was consumed influenced perception of two different samples. Virtual environments were formed by processing custom-recorded 360 degree videos and overlaying audio, text, and sensory scales to simulate a typical sensory evaluation. Participants were asked to taste two alcoholic beverages, a beer and a sparkling wine, in two virtual contexts, a bar and a winery. The results indicated that participants’ willingness to pay for, and overall enjoyment of the sparkling wine increased when placed in the winery context, with no change between the two virtual contexts for the beer sample. This occurred without alteration of the samples’ sensory properties or the ability of panelists to identify the beverage they were drinking; however, perceived appropriateness of the samples for the setting was strongly influenced by the context in which they were sampled, suggesting that perceived appropriateness for a surrounding may play a role in the degree to which we enjoy a food. Results provide further proof that artificially-applied context, such as that provided by virtual reality, can further the sensory testing of foods

    An aggregated template methodology: Novel automatic phase-onset identification by template matching

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    The precision of P- and S-wave phase picking strongly determines the precision of earthquake locations, but such picking can be challenging in the case of emergent signals, large data sets or temporally varying seismic networks. To overcome these challenges, we have developed the concept of an aggregated template to perform automatic picking of the P- and S-wave phases. An aggregated template is defined as a representative event for a small area, built by aggregating the best signal-to-noise-ratio seismic traces from events with similar waveforms (i.e. multiplet events). A template matching procedure, based on the cross-correlation between an aggregated template and an unpicked event, automatically determines the unpicked event P- and S-wave phases. This method enables (1) consistent and accurate P- and S-wave phase picking and (2) reduces processing time relative to traditional template matching by using a clustering method that finds the most representative templates for a region, and thus limiting the required number of templates. We established two parameters to weight the picking precision: (1) the cross-correlation between the aggregated template and the unpicked event and (2) the number of P- and S-wave picks determined per event. We tested this method on 2100 events recorded in the south-west of Iceland. Nineteen aggregated templates have been defined and used to automatically pick ∼65% of the complete event catalogue with an accuracy within the range of the manual picking uncertainty. These automatically picked events can then be used for event location, even when characterized by low magnitude, low signal to noise ratios and with emergent P-wave signals

    Array Signal Processing on Distributed Acoustic Sensing Data: Directivity Effects in Slowness Space

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    Distributed Acoustic Sensing (DAS) involves the transmission of laser pulses along a fiber-optic cable. These pulses are backscattered at fiber inhomogeneities and again detected by the same interrogator unit that emits the pulses. Elastic deformation along the fiber causes phase shifts in the backscattered laser pulses which are converted to spatially averaged strain measurements, typically at regular fiber intervals. DAS systems provide the potential to employ array processing algorithms. However, there are certain differences between DAS and conventional sensors. While seismic sensors typically record the directional particle displacement, velocity, or acceleration, the DAS axial strain is inherently proportional to the spatial gradient of the axial cable displacement. DAS is therefore insensitive to broadside displacement, for example, broadside P-waves. In classical delay-and-sum beamforming, the array response function is the far-field response on a horizontal slowness (or wavenumber) grid. However, for geometrically non-linear DAS layouts, the angle between wavefront and cable varies, requiring the analysis of a steered response that varies with the direction of arrival. This contrasts with the traditional array response function which is given in terms of slowness difference between arrival and steering. This paper provides a framework for DAS steered response estimation accounting also for cable directivity and gauge-length averaging – hereby demonstrating the applicability of DAS in array seismology and to assess DAS design aspects. It bridges a gap between DAS and array theory frameworks and communities, facilitating increased employment of DAS as a seismic array, while providing building blocks for the development of DAS array design tools
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