1,636 research outputs found

    Olivines in angrite LEW 87051: Phenos or xenos

    Get PDF
    Nyquist et al. recently reported the presence of live Mn-53 in angrite LEW 86010 when it crystallized. Hence, melting must have occurred within approx. 10 Ma of the accretion of the angrite parent body, and LEW 86010 is the oldest known differentiated meteorite. This discovery has made it even more desirable to understand teh petrogenesis of angrites, which presumably were all formed at a similar time. As part of the continuing work on angrite petrogenesis, crystallization experiments were conducted on LEW 87051, the other Antarctic angrite, to clarify its petrogenesis. Several aspects of the experimental work is reported. Although the details are not understood, it is clear that the Cr abundance in the experimental olivines must be controlled by spinel crystallization

    The accordian and the deep bowl of spaghetti: Eight researchers' experiences of using IPA as a methodology

    Get PDF
    Since 1996 Interpretative Phenomenological Analysis (IPA) has grown rapidly and been applied in areas outside its initial ā€œhomeā€ of health psychology. However, explorations of its application from a researcher's perspective are scarce. This paper provides reflections on the experiences of eight individual researchers using IPA in diverse disciplinary fields and cultures. The research studies were conducted in the USA, Malaysia, Australia, New Zealand, Ireland and the UK by researchers with backgrounds in business management, consumer behaviour, mental health nursing, nurse education, applied linguistics, clinical psychology, health and education. They variously explored media awareness, employee commitment, disengagement from mental health services, in-vitro fertilisation treatment, student nurses' experience of child protection, second language acquisition in a university context, the male experience of spinal cord injury and academics experience of working in higher education and womenā€™s experiences of body size and health practices. By bringing together intercultural, interdisciplinary experiences of using IPA, the paper discusses perceived strengths and weaknesses of IPA

    TimeSets for uncertainty visualisation

    Get PDF
    TimeSets consist of a timeline showing sequence of events displayed across a visualisation, while makings sense of sets relation among events in the timeline [NXWW15]. This study looked into extending TimeSets to accommodate Visualisation of trust and uncertainty as parts of its variables for events displayed across the timeline. The aim of the challenge is to build tools in the context of big data analytics that can be used to aid military operations through intelligence analytics and decision-making

    Synthetic and natural Nakhla pyroxenes: Parent melt composition and REE partition coefficients

    Get PDF
    Nakhla is one of the SNC meteorites, generally believed to be of martian origin. It is composed mainly of cumulus augite, in which primary igneous zoning is apparently preserved, and which serves as a recorder of the composition of Nakhla's parent melt and the conditions under which it crystallized. Knowledge of the composition and petrogenesis of this parent melt may help unravel Nakhla's relationship to the other SNC's, and provide clues to martian petrogenesis in general. This abstract reports new results of an ongoing study in which we are (1) comparing the major and minor element compositions of synthetic pyroxenes crystallized from various proposed parent melt compositions with those in Nakhla pyroxene to constrain the composition of the parent melt, and (2) measuring minor and trace element partition coefficients, particularly those of the REE, in order to obtain the most applicable D values with which to invert the natural pyroxene compositions to obtain the trace element composition of the parent melt. Results suggest that recent estimates of Nakhla's parent melt composition are too aluminous, and that mafic or ultramafic melts are more likely candidates

    The Nakhla parent melt: REE partition coefficients and clues to major element composition

    Get PDF
    Nakhla is one of the SNC meteorites, generally believed to be of Martian origin. It is a medium-grained augite-olivine cumulate with a variolitic groundmass of sodic plagioclase, alkali feldspar, and Fe-rich pyroxenes and olivine. One of the major tasks in deciphering Nakhla's petrogenesis is determining the composition of its parent melt. Gaining an understanding of the composition and petrogenesis of this parent melt may help unravel Nakhla's relationship to the other SNCs, and provide clues to Martian petrogenesis in general. Our experimental partitioning studies provide new information that helps constrain both the major and trace element composition of the Nakhla parent melt

    Contrastive Learning for Self-Supervised Pre-Training of Point Cloud Segmentation Networks With Image Data

    Full text link
    Reducing the quantity of annotations required for supervised training is vital when labels are scarce and costly. This reduction is particularly important for semantic segmentation tasks involving 3D datasets, which are often significantly smaller and more challenging to annotate than their image-based counterparts. Self-supervised pre-training on unlabelled data is one way to reduce the amount of manual annotations needed. Previous work has focused on pre-training with point clouds exclusively. While useful, this approach often requires two or more registered views. In the present work, we combine image and point cloud modalities by first learning self-supervised image features and then using these features to train a 3D model. By incorporating image data, which is often included in many 3D datasets, our pre-training method only requires a single scan of a scene and can be applied to cases where localization information is unavailable. We demonstrate that our pre-training approach, despite using single scans, achieves comparable performance to other multi-scan, point cloud-only methods.Comment: In Proceedings of the Conference on Robots and Vision (CRV'23), Montreal, Canada, Jun. 6-8, 2023. arXiv admin note: substantial text overlap with arXiv:2211.1180

    The evolution of Araliaceae : a phylogenetic analysis based on ITS sequences of nuclear ribosomal DNA

    Get PDF
    Phylogenetic analyses of ITS sequence data from 70 species and 40 genera of Araliaceae (representing all major lineages within the "core group" of the family) do not support the widely used traditional division of Araliaceae into three tribes. Tribe Aralieae (characterized by imbricate petals) is found nested within a paraphyletic Schefflerieae (whose taxa have valvate petals). There are, however, two large monophyletic groups comprising most araliad genera: the "Aralia-Polyscias-Pseudopanax group" (which includes Aralia, Meryta, Munroidendron, Panax, Pentapanax, Polyscias, Pseudopanax, Reynoldsia, Sciadodendron, Tetraplasandra, and their close allies), and the "Eleutherococcus-Dendropanax-Schefflera group" (including Brassaiopsis, Dendropanax, Eleutherococcus, Fatsia, Hedera, Oreopanax, Schefflera, Sinopanax, and their close allies). The ITS trees also permit a re-evaluation of several taxonomically important morphological characters (e.g., petal aestivation, leaf architecture, carpel number, and habit), and provide the opportunity to assess traditional generic delimitations in the family. Four of the largest genera appear to be either polyphyletic (Schefflera, Pseudopanax) or paraphyletic (Aralia, Polyscias), but further studies will be needed to fully re-define these complex taxa. Outgroup comparisons and the placement of Astrotricha and Osmoxylon (in basally-branching lineages in Araliaceae) help to confirm a paleotropical origin of the family. The ITS topologies suggest that biogeographic radiations into different tropical/subtropical regions and into the north and south temperate regions occurred early in the history of core Araliaceae. Temperate taxa have arisen several times independently from tropical and subtropical relatives, although a few subtropical taxa may be found nested within temperate clades (e.g., Pentapanax within Aralia). Migrations between the Old and New Worlds are also suggested for several taxa, including Aralia, Panax, Oplopanax, and the Sinopanax-Oreopanax generic pair

    The Effect of Static Stretching on Proprioception, Pennation Angle, and Muscle Power Production

    Get PDF
    With widespread use of pre-exercise stretching methods across sport and exercise, recent studies have questioned the effectiveness of such methods (Kay & Blazevich 2012; Cramer et al., 2005; Curry, Chengkalath, Crouch, Romance, & Manns, 2009). The purpose of this study was to examine how the relationship between pennation angle, proprioception, and muscle power are influenced by a static stretching protocol. Participants (n = 17) from a southeastern university in the United States consented to participate and were divided into an experimental group (n = 12) and control group (n = 5). The experimental group engaged in static stretched by placing the right foot on an incline board and maximally dorsiflexing the ankle joint while keeping the bottom of their foot flush with the boardā€™s surface and the knee fully extended. The control group remained seated for the same amount of time and did not engage in stretching. Both groups were measured for vertical jump using the Vertec force plate, electrical activity of the gastrocnemius via the Terason ultrasound machine, and proprioception of the ankle joint via the Biodex 2 dynamometer pre- and post- stretching and control protocols. Results indicated that static stretching resulted in a decrease in muscle power without change of proprioception or electrical-mechanical delay while accompanied by an increase in pennation angle. The increase in pennation angle may the reason why static stretch resulted in a reduction in muscle power. The results are discussed in regard to previous research and future practical application

    High stakes lies: Police and non-police accuracy in detecting deception

    Get PDF
    This is an Accepted Manuscript of an article published by Taylor & Francis in Psychology, Crime and Law on 26 June 2014 available online: http://wwww.tandfonline.com/10.1080/1068316X.2014.935777To date, the majority of investigations in to accuracy in detecting deception have used low stakes lies as stimulus materials, and findings from these studies suggest that people are generally poor at detecting deception. The research presented here utilised real life, high stakes lies as stimulus materials, to investigate the accuracy of police and non-police observers in detecting deception. It was hypothesised that both police and non-police observers would achieve above chance levels of accuracy in detecting deception, that police officers would be more accurate at detecting deception than non-police observers, that confidence in veracity judgements would be positively related to accuracy, and that consensus judgements would predict veracity. 107 observers (70 police officers and 37 non-police participants) watched 36 videos of people lying or telling the truth in an extremely high stakes, real life situation. Police observers achieved mean accuracy in detecting deception of 72%, non-police observers achieved 68% mean accuracy, and confidence in veracity judgements were positively related to accuracy. Consensus judgements correctly predicted veracity in 92% of cases.ESRC grant number ES/I013288/
    • ā€¦
    corecore