949 research outputs found

    Sensor Sleeve: Sensing Affective Gestures

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    We describe the use of textile sensors mounted in a garment sleeve to detect affective gestures. The `Sensor Sleeve' is part of a larger project to explore the role of affect in communications. Pressure activated, capacitive and elasto-resistive sensors are investigated and their relative merits reported on. An implemented application is outlined in which a cellphone receives messages derived from the sleeve's sensors using a Bluetooth interface, and relays the signals as text messages to the user's nominated partner

    A nonparametric characteristics model of the demand for milk

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    Characteristics models in demand analysis capture the idea that people value goods not For the commodity itself but for the characteristics (or attributes) or embodied in the good. For example, agents may care about the fat content and the taste of different sorts of milk but not the actual type of milk. When we have fewer characteristics than types of good the theory imposes restrictions on observables. We present a revealed preference characteristics model analysis of the demand for milk in Denmark

    Submerged Aquatic Bryophytes in Colour Lake, a Naturally Acidic Polar Lake with Occasional Year-round Ice-cover

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    Colour Lake is a small, naturally acidic (pH 3.7) lake on Axel Heiberg Island (Canadian High Arctic) that experiences occasional year-round ice cover. We investigated the benthic vegetation of this lake, with a specific aim of determining whether the annual growth of benthic bryophytes reflects the state of summer ice cover. We found the bed of the lake to be almost completely covered by mosses or liverworts to a depth of 22 m. The mosses showed annual growth bands 10-30 mm in length, visible as changes in leaf density and size. Four to five bands retained recognizable leaves and measurable amounts of chlorophyll-a (chla), and up to 12 bands were recognizable from leaf scars. We could not find a consistent relationship between band length and persistence of ice cover for a given year. We suggest that this lack is due to the complex effects of ice cover on moss growth conditions, specifically on the water temperature and irradiance at depth. Photosynthetic characteristics of Calliergon over a range of light and temperature conditions, determined using pulse amplitude-modulated fluorometry, are presented in support of this argument. We conclude that moss banding patterns are an unreliable method of hindcasting episodic failure of ice to melt in Arctic lakes.Le lac Colour est un petit lac de l'île Axel Heiberg, située dans l'Extrême-Arctique canadien, dont l'acidité (pH = 3,7) est naturelle et qui reste parfois englacé toute l'année. On a étudié la végétation benthique de ce lac, dans le but précis de déterminer si la croissance annuelle des bryophytes benthiques reflète l'état de la couverture de la glace en été. On a trouvé que le lit du lac est presque entièrement recouvert de mousses ou d'hépatiques jusqu'à une profondeur de 22 m. Les mousses affichaient des bandes de croissance annuelles de 10 à 30 mm de longueur, visibles sous la forme d'un changement dans la densité et la taille de la feuille. De 4 à 5 bandes conservaient des feuilles reconnaissables et des quantités mesurables de chlorophylle-a (chla), et jusqu'à 12 bandes étaient reconnaissables d'après les cicatrices foliaires. On n'a pu trouver de rapport constant entre la longueur de la bande et la persistance du manteau glaciel pour une année donnée. On suggère que ce manque est dû aux effets complexes du manteau glaciel sur les conditions de croissance de la mousse, en particulier sur la température de l'eau et l'irradiance en profondeur. Les attributs photosynthétiques de Calliergon pour une gamme de conditions d'éclairement et de température données, déterminés par fluorimétrie par impulsions à amplitude modulée, sont présentés à l'appui de cette thèse. On conclut que les schémas de rubanement de la mousse constituent une méthode peu fiable de prévision a posteriori des interruptions épisodiques de fonte de la glace dans les lacs arctiques

    Influence of feed ration size on somatic and muscle growth in landlocked dwarf and farmed Atlantic salmon Salmo salar

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    We examined the possible adaptation of the dwarf Bleke population of Atlantic salmon Salmo salar from Lake Byglandsfjord in southern Norway to limited food resources. The growth performance and muscle development in juvenile Bleke and farmed S. salar under satiated or restricted (50%) feeding were examined for 10 months, starting 3 weeks after first‐feeding stage. Four‐thousand fish were divided into four replicated groups and random samples of 16–40 fish per group were measured six times during the experiment. The two strains showed no significant difference in mean body mass when fed restricted ration, but the individual variation was considerably higher in the farmed fish. Both Bleke and farmed S. salar grew significantly faster when fed to satiation, but the farmed S. salar showed much higher gain in mass and were three times heavier (201.5 g v. 66.7 g) and possessed twice as many fast muscle fibres (179682 v. 84779) compared with landlocked S. salar after 10 months. Farmed fish fed full ration displayed both hypertrophic and hyperplasic muscle growth, while the increased growth in Bleke S. salar was entirely associated with a larger fibre diameter. The landlocked Bleke strain has apparently adapted to low food availability by minimising the metabolic costs of maintenance and growth through reduced dominance hierarchies and by an increase in average muscle fibre diameter relative to the ancestral condition.PostprintPeer reviewe

    Runoff and focused groundwater recharge response to flooding rains in the arid zone of Australia

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    A groundwater recharge investigation in the arid zone of Australia is presented. The investigation used a wide range of hydrogeological techniques including geological mapping, surface and borehole geophysics, groundwater hydraulics, streambed temperature and pressure monitoring, and hydrogeochemical and environmental tracer sampling, and it was complemented by analysis of rainfall intensity from 18 tipping-bucked rain gauges, climate data and stream runoff measurements. Run-off and recharge from a 200-mm rainfall event in January 2015, the largest daily rainfall in the local 50-year record, were investigated in detail. While this major storm provided substantial run-off as a potential source for focused, indirect recharge, it only produced enough actual recharge to the shallow aquifer to temporarily halt a long-term groundwater recession. A series of smaller rainfall-runoff events in 2016 produced a similar recharge response. The results suggest that the total magnitude of a flood event is not the main control on indirect groundwater recharge at this location. A deeper aquifer shows no hydraulic response to surface-water flow events and is isolated from the shallow system, consistent with its Pleistocene groundwater age. This supports a growing body of evidence indicating that attributing or predicting generalised changes in recharge to changes in climate in dryland environments should not be attempted without first unravelling the dynamic processes governing groundwater recharge in the locality of interest. The results should prompt more detailed and long-term field investigation in other arid zone locations to further understand the episodic and nonlinear nature of recharge in such environments
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