4,790 research outputs found

    Viscous vortex flows

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    Several computational studies are currently being pursued that focus on various aspects of representing the entire lifetime of the viscous trailing vortex wakes generated by an aircraft. The formulation and subsequent near-wing development of the leading-edge vortices formed by a delta wing are being calculated at modest Reynolds numbers using a three-dimensional, time-dependent Navier-Stokes code. Another computational code was developed to focus on the roll-up, trajectory, and mutual interaction of trailing vortices further downstream from the wing using a two-dimensional, time-dependent, Navier-Stokes algorithm. To investigate the effect of a cross-wind ground shear flow on the drift and decay of the far-field trailing vortices, a code was developed that employs Euler equations along with matched asymptotic solutions for the decaying vortex filaments. And finally, to simulate the conditions far down stream after the onset of the Crow instability in the vortex wake, a full three-dimensional, time-dependent Navier-Stokes code was developed to study the behavior of interacting vortex rings

    Inclusive Practice: researching the relationships between dyslexia, personality, and art students’ drawing ability.

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    This paper addresses the conference theme of inclusivity from two standpoints. Firstly, involving collaboration between researchers from fields including psychology, educational study support and studio drawing practice, which has revealed insights into students’ learning difficulties in drawing, which are not easily accessible through mono-disciplinary research practice. Secondly it involves a proposal outlining a strategy for the teaching of drawing which attempts to include students of varying abilities in drawing, and to empower their practice equally. The paper demonstrates the effectiveness of an inclusive, cross-disciplinary approach to exploring the relations between personality factors, perceptual problems, visual memory and drawing skills in art students who report difficulties producing accurate drawn representations of their observational experiences. Results indicate that whilst in general drawing ability seems not to relate to dyslexia, higher drawing ability does appear related to the personality measure of conscientiousness, and also both to sex (in the biological sense, males drawing better than females) and to gender (those who perceive themselves as more masculine drawing better, whether they are male or female). Poor drawers are less good at accurately copying angles and proportions, and their visual memory is less good. These findings inform a proposed inclusive group teaching strategy for drawing which attempts to address these weaknesses without hindering the progress of the more able student

    Athena

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    The Athena simulation software supports an analyst from DoD or other federal agency in making stability and reconstruction projections for operational analyses in areas like Iraq or Afghanistan. It encompasses the use of all elements of national power: diplomatic, information, military, and economic (DIME), and anticipates their effects on political, military, economic, social, information, and infrastructure (PMESII) variables in real-world battle space environments. Athena is a stand-alone model that provides analysts with insights into the effectiveness of complex operations by anticipating second-, third-, and higher-order effects. For example, the first-order effect of executing a curfew may be to reduce insurgent activity, but it may also reduce consumer spending and keep workers home as second-order effects. Reduced spending and reduced labor may reduce the gross domestic product (GDP) as a third-order effect. Damage to the economy will have further consequences. The Athena approach has also been considered for application in studies related to climate change and the smart grid. It can be applied to any project where the impacts on the population and their perceptions are important, and where population perception is important to the success of the project

    Silicon based microfluidic cell for terahertz frequencies

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    We present a detailed analysis of the design, fabrication and testing of a silicon based, microfluidic cell, for transmission terahertz time-domain spectroscopy. The sensitivity of the device is tested through a range of experiments involving primary alcohol/water mixtures. The dielectric properties of these solutions are subsequently extracted using a Nelder–Mead search algorithm, and are in good agreement with literature values obtained via alternative techniques. Quantities in the order of 2 Όmol can be easily distinguished for primary alcohols in solution, even with the subwavelength optical path lengths used. A further display of the device sensitivity is shown through the analysis of commercial whiskeys, where there are clear, detectable differences between samples. Slight absorption variations were identified between samples of the same commercial brand, owing to a 2.5% difference in their alcoholic content. Results from data taken on subsequent days after system realignment are also presented, confirming the robustness of the technique, and the data extraction algorithm used. One final experiment, showing the possible use of this device to analyze aqueous biological samples is detailed; where biotin, a molecule known for its specific terahertz absorptions, is analyzed in solution. The device sensitivity is once again displayed, where quantities of 3 nmol can be clearly detected between samples

    Convergent metabotropic signalling pathways inhibit SK channels to promote synaptic plasticity in the hippocampus

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    Hebbian synaptic plasticity at hippocampal Schaffer collateral synapses is tightly regulated by postsynaptic SK channels that restrict NMDA receptor activity. SK channels are themselves modulated by G-protein-coupled signalling pathways, but it is not clear under what conditions these are activated to enable synaptic plasticity. Here, we show that muscarinic M1 receptor (M1R) and type 1 metabotropic glutamate receptor (mGluR1) signalling pathways, which are known to inhibit SK channels and thereby disinhibit NMDA receptors, converge to facilitate spine calcium transients during the induction of long-term potentiation (LTP) at hippocampal Schaffer collateral synapses onto CA1 pyramidal neurons of male rats. Furthermore, mGluR1 activation is required for LTP induced by reactivated place cell firing patterns that occur in sharp wave ripple events during rest or sleep. In contrast, M1R activation is required for LTP induced by place cell firing patterns during exploration. Thus, we describe a common mechanism that enables synaptic plasticity during both encoding and consolidation of memories within hippocampal circuits

    Negotiating daughterhood and strangerhood: retrospective accounts of serial migration

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    Most considerations of daughtering and mothering take for granted that the subjectivities of mothers and daughters are negotiated in contexts of physical proximity throughout daughters’ childhoods. Yet many mothers and daughters spend periods separated from each other, sometimes across national borders. Globally, an increasing number of children experience life in transnational families. This paper examines the retrospective narratives of four women who were serial migrants as children (whose parents migrated before they did) . It focuses on their accounts of the reunion with their mothers and how these fit with the ways in which they construct their mother-daughter relationships. We take a psychosocial approach by using a psychoanalytically-informed reading of these narratives to acknowledge the complexities of the attachments produced in the context of migration and to attend to the multi-layered psychodynamics of the resulting relationships. The paper argues that serial migration positioned many of the daughters in a conflictual emotional landscape from which they had to negotiate ‘strangerhood’ in the context of sadness at leaving people to whom they were attached in order to join their mothers (or parents). As a result, many were resistant to being positioned as daughters, doing daughtering and being mothered in their new homes

    Community views on ‘Can perinatal services safely identify Aboriginal and Torres Strait Islander parents experiencing complex trauma?’

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    Family and extended kinship systems which nurture healthy, happy children are central to Aboriginal and Torres Strait Islander cultures. Since colonisation, Aboriginal and Torres Strait Islander communities have been impacted by intergenerational cycles of trauma, stemming from colonial violence, genocidal policies and discrimination, including the forced removal of children from their families. Becoming a parent offers a unique life-course opportunity for trauma recovery and preventing intergenerational trauma. However, identifying or ‘recognising’ complex trauma carries significant risk of harm for Aboriginal and Torres Strait Islander parents due to reactive prenatal child protection involvement potentially compounding experiences of trauma, and limited benefits due to lack of culturally appropriate support. The Aboriginal-led participatory Healing the Past by Nurturing the Future project aims to co-design safe, accessible and feasible perinatal awareness, recognition, assessment and support strategies for Aboriginal and Torres Strait Islander parents experiencing complex trauma. This paper presents views of 38 workshop participants to determine prerequisites for ensuring benefits outweigh risks of assessment to safely recognise parents experiencing complex trauma, consistent with screening criteria. Six essential elements were identified from thematic analysis: high-quality holistic care; cultural, social and emotional safety; empowerment, choice and control; flexible person-centred approaches; trusting relationships; and sensitive, skilled communication

    Searching for music: understanding the discovery, acquisition, processing and organization of music in a domestic setting for design

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    This series of studies make it clear that a wide range of both physical and digital resources are involved in domestic music consumption. The selection of digital resources is particularly evident, and it can be observed that domestic music consumption is a fragmented business, taking advantage of many different "channels'' for getting, using and preparing music. While there are not a series of common channels, each home displayed a variety of methods in respect to using metadata in multiple different modalities: regardless, the activities involved in getting, using and preparing music cohere through a noticeable, emergent set of workflows. We find that not only does metadata support searching, as one might expect, but also it pervades all parts of the workflow and is used in real-time as a reflexive artifact and in terms of its future perceived/prescribed use. The findings of the research raise a series of possibilities and issues that form the basis for understanding and designing for metadata use
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