1,895 research outputs found

    Time to guide: evidence for delayed attentional guidance in contextual cueing

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    Contextual cueing experiments show that, when displays are repeated, reaction times (RTs) to find a target decrease over time even when the observers are not aware of the repetition. Recent evidence suggests that this benefit in standard contextual cueing tasks is not likely to be due to an improvement in attentional guidance (Kunar, Flusberg, Horowitz, & Wolfe, 2007). Nevertheless, we ask whether guidance can help participants find the target in a repeated display, if they are given sufficient time to encode the display. In Experiment 1 we increased the display complexity so that it took participants longer to find the target. Here we found a larger effect of guidance than in a condition with shorter RTs. Experiment 2 gave participants prior exposure to the display context. The data again showed that with more time participants could implement guidance to help find the target, provided that there was something in the search stimuli locations to guide attention to. The data suggest that, although the benefit in a standard contextual cueing task is unlikely to be a result of guidance, guidance can play a role if it is given time to develop

    Relict Late Wisconsinan Dune Fields of the Northern Great Plains, Canada

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    Late Wisconsinan dune activity is investigated within the present-day boreal forest and parkland regions of the northern Great Plains, Canada, to extend the understanding of the spatial and temporal eolian record. Optical ages from stabilized sand dunes document the timing of past activity. Eolian activity ranges from about 16 ka in west-central Alberta to 9 ka in northwestern Saskatchewan. Between about 16 and 13 ka, dune activity in central Alberta occurred in an ice-proximal tundra setting along the margins of the Laurentide and Cordilleran ice sheets. Predominant dune-forming winds were from the west and northwest. Dune activity continued in this area between about 13 and 11 ka within parkland and grassland settings as the Laurentide Ice Sheet retreated to the northeast. Winds continued to blow from the west and northwest, and the climate was likely influenced by an increasingly dominant Pacific air mass. Also beginning at about 13 ka, dune-forming winds along the margins of the retreating Laurentide Ice Sheet were influenced by anticyclonic winds from the southeast that were maintained until about 9 ka. As the Laurentide Ice Sheet retreated, these southeasterly anticyclonic winds were successively replaced by winds from the northwest associated with the Pacific air mass. Dune activity across the region terminated in a time-transgressive manner from the southwest, at about 11 ka, to the northeast, at about 9 ka, with the establishment of boreal forest vegetation and reduced wind strength.Les auteurs étudient l’activité dunaire au Wisconsinien tardif dans la forêt boréale et la prairie-parc actuelles des Grandes Plaines septentrionales du Canada, afin d’approfondir les connaissances sur l’évolution spatiotemporelle de l’activité éolienne. Les âges optiques mesurés sur des dunes de sable stabilisées permettent de reconstituer la chronologie de l’activité passée. Les âges de l’activité éolienne s’échelonnent entre 16 ka dans le centre-ouest de l’Alberta et 9 ka dans le nord-ouest de la Saskatchewan. Entre 16 et 13 ka, l’activité dunaire dans le centre de l’Alberta a eu lieu dans un environnement de toundra juxtaglaciaire le long des marges des inlandsis laurentidien et cordillérien. Les vents efficaces prédominants soufflaient de l’ouest et du nord-ouest. L’activité dunaire s’est poursuivie dans cette région entre 13 et 11 ka dans des environnements de prairie-parc et de prairie herbageuse, avec le recul de l’Inlandsis laurentidien vers le nord-est. Les vents ont continué de souffler de l’ouest et du nord-ouest, et le climat a probablement été influencé par une masse d’air du Pacifique de plus en plus dominante. Également au début de 13 ka, les vents efficaces le long des marges de l’Inlandsis laurentidien en recul ont été influencées par des vents anticycloniques du sud-ouest, qui ont duré jusqu’à 9 ka. Avec le retrait de l’Inlandsis laurentidien, ces vents ont été successivement remplacés par des vents du nord-ouest associés à la masse d’air du Pacifique. L’activité dunaire dans la région s’est terminée de façon diachrone à partir du sud-ouest, vers 11 ka, jusqu’au nord-est, vers 9 ka, par l’établissement d’une végétation forestière boréale et la diminution de la force des vents

    Potential Aboriginal-Occupation-Induced Dune Activity, Elbow Sand Hills, Northern Great Plains, Canada

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    Geomorphological and archeological evidence indicates potential linkages between Plains aboriginal occupation and dune activity in the Elbow Sand Hills of southern Saskatchewan, Canada. Vegetation encroachment has rapidly outpaced migration of an active dune complex over the last 65 years. Optical ages of stabilized dune remnants indicate that dune activity predates Euro-Canadian settlement (ca. AD 1900). Early Euro-Canadian explorers observed local occupation and exploitation of the sand hills by aboriginal groups for herding and impounding bison. Mapping of archeological sites in relation to physiography reveals that sand dunes, in close proximity to permanent water resources, were preferred areas of occupation. Collectively, these results support the hypothesis that aboriginal occupation disturbance may have perpetuated dune activity in the Elbow Sand Hills until the late 19th century, and that Euro-Canadian settlement and land use emphasizing conservation may have encouraged recent stabilization. We propose that similar aboriginal occupation disturbances may have been responsible for perpetuating dune activity in other dune fields in the Great Plains. To this end, climatic variability should not be considered exclusive of other drivers of dune activity in semivegetated inland dune fields of the Great Plains

    Legume based plant mixtures for delivery of multiple ecosystem services: An overview of benefits

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    As costs for mineral fertilizers rise, legume-based leys are recognised as a potential alternative nitrogen source for crops. Here we demonstrate that including species-rich legume-based leys in the rotation helps to maximize synergies between agricultural productivity and other ecosystem services. By using functionally diverse plant species mixtures these services can be optimised and fine-tuned to regional and farm-specific needs. Field experiments run over three years at multiple locations showed that the stability of ley performance was greater in multi-species mixtures than in legume monocultures. In addition, mixing different legume species in the ley helps to suppress both early and late weeds. Further, combining complementary phenologies of different legume species extended forage availability for key pollinator species. Finally, widening the range of legume species increases opportunities to build short term leys into rotations on conventional farms via cover cropping or undersowing

    F.A.R.O.G. FORUM, Vol. 5 No. 6

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    https://digitalcommons.library.umaine.edu/francoamericain_forum/1018/thumbnail.jp

    Protocol: Evaluating the impact of a nation-wide train-the-trainer educational initiative to enhance the quality of palliative care for children with cancer

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    Background: There are identified gaps in the care provided to children with cancer based on the self-identified lack of education for health care professionals in pediatric palliative care and in the perceptions of bereaved parents who describe suboptimal care. In order to address these gaps, we will implement and evaluate a national roll-out of Education in Palliative and End-of-Life Care for Pediatrics (EPEC (R)-Pediatrics), using a 'Train-the-Trainer' model.Methods/design: In this study we are using a pre-post-test design and an integrated knowledge translation approach to assess the impact of the educational roll-out in four areas: 1) self-assessed knowledge of health professionals; 2) knowledge dissemination outcomes; 3) practice change outcomes; and 4) quality of palliative care. The quality of palliative care will be assessed using data from three sources: a) parent and child surveys about symptoms, quality of life and care provided; b) health record reviews of deceased patients; and c) bereaved parent surveys about end-of-life and bereavement care. After being trained in EPEC (R)-Pediatrics, 'Master Facilitators' will train 'Regional Teams' affiliated with 16 pediatric oncology programs in Canada. Each team will consist of three to five health professionals representing oncology, palliative care, and the community. Each team member will complete online modules and attend one of two face-to-face conferences, where they will receive training and materials to teach the EPEC (R)-Pediatrics curriculum to 'End-Users' in their region. Regional Teams will also choose a Tailored Implementation of Practice Standards (TIPS) Kit to guide implementation of a quality improvement project in their region; support will be provided via quarterly meetings with Co-Leads and via a listserv and webinars with other teams.Discussion: Through this study we aim to raise the level of pediatric palliative care education amongst health care professionals in Canada. Our study will be a significant step forward in evaluation of the impact of EPEC (R)-Pediatrics both on dissemination outcomes and on care quality at a national level. Based on the anticipated success of our project we hope to expand the EPEC (R)-Pediatrics roll-out to health professionals who care for children with non-oncological life-threatening conditions
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