2,144 research outputs found

    Aquatic Insects as Inhalant Allergens : A Review of American Literature

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    Author Institution: University of Vermont, Burlington, Vermonthis article reviews American literature concerning the matter of certain aquatic insects as causes of allergic distress. The effects of bites and stings are not included. Mayflies (Ephemeroptera) were cited as a cause of hay fever as early as 1913. Inhalation of body fragments of mayflies is believed to be the causative agent. Similar medical histories are associated with the caddisflies (Trichoptera). The incidence of sensitivity to these insects is sufficiently large to consider this problem to be of general medical interest. Some evidence indicates that persons continually exposed to these insects could develop sensitivities to them. Allergists are now studying the biochemical and immunological aspects of insect allergy. A selected list of references is included with the articl

    Environmental study of ERTS-1 imagery: Lake Champlain and Vermont

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    Environmental concerns of the State of Vermont currently being stressed include water quality in Lake Champlain and a state-wide land use and capability plan. Significant results obtained from ERTS-1 relate directly to the above concerns. Industrial water pollution and turbidity in Lake Champlain have been identified and mapped and the ERTS pollution data will be used in the developing court suit which Vermont has initiated against the polluters. ERTS imagery has also provided a foundation for updating and revising land use inventories. Major classes of land use have been identified and mapped, and substantial progress has been made toward the mapping of such land use divisions as crop and forest type, and wetlands

    The effect of indentation force and displacement on visual perception of compliance

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    This paper investigates the effect of maximum indentation force and depth on people's ability to accurately discriminate compliance using indirect visual information only. Participants took part in two psychophysical experiments in which they were asked to choose the 'softest' sample out of a series of presented sample pairs. In the experiments, participants observed a computer-actuated tip indent the sample pairs to one of two conditions; maximum depth (10mm) or maximum force (4N). This indentation process simulates tool operated palpation in laparoscopic surgery. Results were used to plot psychometric functions as a measure of accuracy of compliance discriminability. A comparison indicated that participants performed best in the task where they judged samples being indented to a pre-set maximum force relying solely on visual cues, which demonstrates the effect of visual information on compliance discrimination. Results also show that indentation cues such as force and deformation depth have different effects on our ability to visually discriminate compliance. These findings will inform future work on designing a haptic feedback system capable of augmenting visual and haptic information independently for optimal compliance discrimination performance

    Community refinement of glaucoma referrals

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    The impact of visual cues on haptic compliance discrimination using a pseudo-haptic robotic system

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    A psychophysical magnitude estimation experiment was set up to determine the extent of the contribution of visual feedback during haptic compliance discrimination. Subjects remotely palpated physical compliant samples using a novel pseudo-haptic feedback system which allowed for independent manipulation of visual and haptic feedback. Subjects were asked to rate the compliance of a test sample based on that of a reference sample. While visual feedback was modified by switching the physical test samples shown to participants during indentation, haptic compliance of the test samples was always identical to that of the reference sample. Any variations in haptic sensation was a result of pseudo-haptic illusions. Ratings were collated and fitted to Steven's power law as well as Weber's law. A 0.18 power exponent suggests that the system was successful in generating viscoelastic properties through variations in visual information only. A 19.6% visual change from the reference compliance was necessary in order to perceive a change in haptic compliance using the pseudo-haptic system. These findings could prove beneficial in research and educationalfacilities where advanced force feedback devices are limited or inaccessible, where the concept of pseudo-haptics could be used to simulate various mechanical properties of virtual tissue for training purposes without the needfor complicated or costly force feedback

    Observation of Quantum Effects in sub Kelvin Cold Reactions

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    There has been a long-standing quest to observe chemical reactions at low temperatures where reaction rates and pathways are governed by quantum mechanical effects. So far this field of Quantum Chemistry has been dominated by theory. The difficulty has been to realize in the laboratory low enough collisional velocities between neutral reactants, so that the quantum wave nature could be observed. We report here the first realization of merged neutral supersonic beams, and the observation of clear quantum effects in the resulting reactions. We observe orbiting resonances in the Penning ionization reaction of argon and molecular hydrogen with metastable helium leading to a sharp increase in the absolute reaction rate in the energy range corresponding to a few degrees kelvin down to 10 mK. Our method is widely applicable to many canonical chemical reactions, and will enable a breakthrough in the experimental study of Quantum Chemistry

    Neurophysiological signatures of Alzheimer's disease and frontotemporal lobar degeneration : pathology versus phenotype

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    The disruption of brain networks is characteristic of neurodegenerative dementias. However, it is controversial whether changes in connectivity reflect only the functional anatomy of disease, with selective vulnerability of brain networks, or the specific neurophysiological consequences of different neuropathologies within brain networks. We proposed that the oscillatory dynamics of cortical circuits reflect the tuning of local neural interactions, such that different pathologies are selective in their impact on the frequency spectrum of oscillations, whereas clinical syndromes reflect the anatomical distribution of pathology and physiological change. To test this hypothesis, we used magnetoencephalography from five patient groups, representing dissociated pathological subtypes and distributions across frontal, parietal and temporal lobes: amnestic Alzheimer's disease, posterior cortical atrophy, and three syndromes associated with frontotemporal lobar degeneration. We measured effective connectivity with graph theory-based measures of local efficiency, using partial directed coherence between sensors. As expected, each disease caused large-scale changes of neurophysiological brain networks, with reductions in local efficiency compared to controls. Critically however, the frequency range of altered connectivity was consistent across clinical syndromes that shared a likely underlying pathology, whilst the localization of changes differed between clinical syndromes. Multivariate pattern analysis of the frequency-specific topographies of local efficiency separated the disorders from each other and from controls (accuracy 62% to 100%, according to the groups' differences in likely pathology and clinical syndrome). The data indicate that magnetoencephalography has the potential to reveal specific changes in neurophysiology resulting from neurodegenerative disease. Our findings confirm that while clinical syndromes have characteristic anatomical patterns of abnormal connectivity that may be identified with other methods like structural brain imaging, the different mechanisms of neurodegeneration also cause characteristic spectral signatures of physiological coupling that are not accessible with structural imaging nor confounded by the neurovascular signalling of functional MRI. We suggest that these spectral characteristics of altered connectivity are the result of differential disruption of neuronal microstructure and synaptic physiology by Alzheimer's disease versus frontotemporal lobar degeneration.Peer reviewe

    MRI-based anatomical characterisation of lower-limb muscles in older women

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    The ability of muscles to produce force depends, among others, on their anatomical features and it is altered by ageing-associated weakening. However, a clear characterisation of these features, highly relevant for older individuals, is still lacking. This study hence aimed at characterising muscle volume, length, and physiological cross-sectional area (PCSA) and their variability, between body sides and between individuals, in a group of post-menopausal women. Lower-limb magnetic resonance images were acquired from eleven participants (69 (7) y. o., 66.9 (7.7) kg, 159 (3) cm). Twenty-three muscles were manually segmented from the images and muscle volume, length and PCSA were calculated from this dataset. Personalised maximal isometric force was then calculated using the latter information. The percentage difference between the muscles of the two lower limbs was up to 89% and 22% for volume and length, respectively, and up to 84% for PCSA, with no recognisable pattern associated with limb dominance. Between-subject coefficients of variation reached 36% and 13% for muscle volume and length, respectively. Generally, muscle parameters were similar to previous literature, but volumes were smaller than those from in-vivo young adults and slightly higher than ex-vivo ones. Maximal isometric force was found to be on average smaller than those obtained from estimates based on linear scaling of ex-vivo-based literature values. In conclusion, this study quantified for the first time anatomical asymmetry of lower-limb muscles in older women, suggesting that symmetry should not be assumed in this population. Furthermore, we showed that a scaling approach, widely used in musculoskeletal modelling, leads to an overestimation of the maximal isometric force for most muscles. This heavily questions the validity of this approach for older populations. As a solution, the unique dataset of muscle segmentation made available with this paper could support the development of alternative population-based scaling approaches, together with that of automatic tools for muscle segmentation

    Developing a Labeled Affective Magnitude scale and Fuzzy Linguistic scale for tactile feeling

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    Affective design is the inclusion or representation of human emotions and subjective impressions in product design processes. In affective design, a number of different scales are commonly used to reveal and measure subjective emotions related to the design features of products. Osgood's Semantic Differential Scale (SDS) is one of the scales that has often been used for this purpose. However, there are some drawbacks in the SDS due to the ordinal nature of the scale that leads to losses or distortions of a significant amount of information and this makes it difficult to justify parametric statistical analysis. In this study, two scales, namely a Labeled Affective Magnitude (LAM) scale and a Fuzzy Linguistic scale, are developed. The LAM scale is an alternative scale based on magnitude estimation and has ratio properties. The Fuzzy Linguistic scale is an interval scale for which responses are linguistic descriptors that are identified with fuzzy numbers or intervals. The scales were developed for tactile feelings because they are an important factor in product evaluation. Statistical analysis was conducted to compare the scales. There was no significant difference between the newly constructed fuzzy scale and 11 point SDS, whereas there was a significant difference between the newly constructed LAM scale and 11 point SDS
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