244 research outputs found

    Arthur Provancher Envelope Addressed to Charlotte Michaud

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    Envelope addressed from Arthur Provancher, Lewiston, Maine, to Charlotte Michaud, Framingham, Massachusetts.https://digitalcommons.usm.maine.edu/michaud-auger/1004/thumbnail.jp

    Letter from Laurette Provancher to Charlotte Michaud 09/29/1979

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    09/29/1979 Letter from Laurette Provancher to Charlotte Michaud.https://digitalcommons.usm.maine.edu/michaud-auger/1001/thumbnail.jp

    Revisions of the afrotropical genera of argidae and species of Pampsilota konow, 1899 (Hymenoptera, Tenthredinoidea)

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    Open Access JournalThe Afrotropical fauna contains five genera of Argidae. These are keyed. New subjective synonyms, followed by the valid name in brackets, are Calarge Enslin, 1911 [Arge Schrank, 1802], Calarge africana Enslin, 1911 [Arge congrua Konow, 1907], Clyparge Pasteels, 1963 [Scobina Lepeletier & Serville, 1828], Clyparge terminalis Pasteels, 1963 [Scobina poecila (Klug, 1834)], and Sterictophora [sic] afra Pasteels, 1963 [Sphacophilus afer comb. n., species inquirenda near S. monjarasi Smith & Morales-Reyes, 2015]. The type material of both C. terminalis and S. afra was probably collected in the New World, but labelled with the wrong locality “Kamerun”. An introduction of both species to Africa, not followed by long-term establishment, seems less likely. The removal of these taxa from the faunal list of the region is recommended. The nine known Afrotropical species of Pampsilota are revised, and an illustrated dichotomous identification key presented, with distribution maps for all species. Four species are here described as new to science: P. dahomeyanus Goergen, Koch & Liston, sp. n., P. nigeriae Liston & Koch, sp. n., P. tsavoensis Liston & Koch, sp. n., and P. zebra Liston & Koch, sp. n. Lectotypes are designated for Pampsilota afer Konow, 1899, and Cipdele africana Mocsáry, 1909. The immature stages and host plant of only one species are known: P. dahomeyanus on Lannea nigritana (Anacardiaceae). Its larval morphology strongly resembles that of European and North American species of Arge. We provisionally retain Pampsilota as a valid genus, although it could justifiably be treated as comprising merely a species group, or groups, within Arge

    The Sociological Benefits of a Parish Survey

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    Scaling hard vertical surfaces with compliant microspine arrays

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    A new approach for climbing hard vertical surfaces has been developed that allows a robot to scale concrete, stucco, brick and masonry walls without using suction or adhesives. The approach is inspired by the mechanisms observed in some climbing insects and spiders and involves arrays of microspines that catch on surface asperities. The arrays are located on the toes of the robot and consist of a tuned, multi-link compliant suspension. In this paper we discuss the fundamental issues of spine allometric scaling versus surface roughness and the suspension needed to maximize the probability that each spine will find a useable surface irregularity and to distribute climbing tensile and shear loads among many spines. The principles are demonstrated with a new climbing robot that can scale a wide range of exterior walls

    Human brain activity related to the tactile perception of stickiness

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    While the perception of stickiness serves as one of the fundamental dimensions for tactile sensation, little has been elucidated about the stickiness sensation and its neural correlates. The present study investigated how the human brain responds to perceived tactile sticky stimuli using functional magnetic resonance imaging (fMRI). To evoke tactile perception of stickiness with multiple intensities, we generated silicone stimuli with varying catalyst ratios. Also, an acrylic sham stimulus was prepared to present a condition with no sticky sensation. From the two psychophysics experiments-the methods of constant stimuli and the magnitude estimation—we could classify the silicone stimuli into two groups according to whether a sticky perception was evoked: the Supra-threshold group that evoked sticky perception and the Infra-threshold group that did not. In the Supra-threshold vs. Sham contrast analysis of the fMRI data using the general linear model (GLM), the contralateral primary somatosensory area (S1) and ipsilateral dorsolateral prefrontal cortex (DLPFC) showed significant activations in subjects, whereas no significant result was found in the Infra-threshold vs. Sham contrast. This result indicates that the perception of stickiness not only activates the somatosensory cortex, but also possibly induces higher cognitive processes. Also, the Supra- vs. Infra-threshold contrast analysis revealed significant activations in several subcortical regions, including the pallidum, putamen, caudate and thalamus, as well as in another region spanning the insula and temporal cortices. These brain regions, previously known to be related to tactile discrimination, may subserve the discrimination of different intensities of tactile stickiness. The present study unveils the human neural correlates of the tactile perception of stickiness and may contribute to broadening the understanding of neural mechanisms associated with tactile perception.ope

    Haptic pop-out of movable stimuli

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    When, in visual and haptic search, a target is easily found among distractors, this is called a pop-out effect. The target feature is then believed to be salient, and the search is performed in a parallel way. We investigated this effect with movable stimuli in a haptic search task. The task was to find a movable ball among anchored distractors or the other way round. Results show that reaction times were independent of the number of distractors if the movable ball was the target but increased with the number of items if the anchored ball was the target. Analysis of hand movements revealed a parallel search strategy, shorter movement paths, a higher average movement speed, and a narrower direction distribution with the movable target, as compared with a more detailed search for an anchored target. Taken together, these results show that a movable object pops out between anchored objects and this indicates that movability is a salient object feature. Vibratory signals resulting from the movable ball were found to be a reasonable explanation regarding the sensation responsible for the pop-out of movability

    Using curvature information in haptic shape perception of 3D objects

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    Are humans able to perceive the circularity of a cylinder that is grasped by the hand? This study presents the findings of an experiment in which cylinders with a circular cross-section had to be distinguished from cylinders with an elliptical cross-section. For comparison, the ability to distinguish a square cuboid from a rectangular cuboid was also investigated. Both elliptical and rectangular shapes can be characterized by the aspect ratio, but elliptical shapes also contain curvature information. We found that an elliptical shape with an aspect ratio of only 1.03 could be distinguished from a circular shape both in static and dynamic touch. However, for a rectangular shape, the aspect ratio needed to be about 1.11 for dynamic touch and 1.15 for static touch in order to be discernible from a square shape. We conclude that curvature information can be employed in a reliable and efficient manner in the perception of 3D shapes by touch
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