23,601 research outputs found

    Vehicle Steering control: A model of learning

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    A hierarchy of strategies were postulated to describe the process of learning steering control. Vehicle motion and steering control data were recorded for twelve novices who drove an instrumented car twice a week during and after a driver training course. Car-driver describing functions were calculated, the probable control structure determined, and the driver-alone transfer function modelled. The data suggested that the largest changes in steering control with learning were in the way the driver used the lateral position cue

    Essential role for PDGF signaling in ophthalmic trigeminal placode induction

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    Much of the peripheral nervous system of the head is derived from ectodermal thickenings, called placodes, that delaminate or invaginate to form cranial ganglia and sense organs. The trigeminal ganglion, which arises lateral to the midbrain, forms via interactions between the neural tube and adjacent ectoderm. This induction triggers expression of Pax3, ingression of placode cells and their differentiation into neurons. However, the molecular nature of the underlying signals remains unknown. Here, we investigate the role of PDGF signaling in ophthalmic trigeminal placode induction. By in situ hybridization, PDGF receptor ÎČ is expressed in the cranial ectoderm at the time of trigeminal placode formation, with the ligand PDGFD expressed in the midbrain neural folds. Blocking PDGF signaling in vitro results in a dose-dependent abrogation of Pax3 expression in recombinants of quail ectoderm with chick neural tube that recapitulate placode induction. In ovo microinjection of PDGF inhibitor causes a similar loss of Pax3 as well as the later placodal marker, CD151, and failure of neuronal differentiation. Conversely, microinjection of exogenous PDGFD increases the number of Pax3+ cells in the trigeminal placode and neurons in the condensing ganglia. Our results provide the first evidence for a signaling pathway involved in ophthalmic (opV) trigeminal placode induction

    Paradox and promise in joint school/university arts research

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    Collaborative university and school research projects are inevitably labour intensive endeavours that require the careful negotiation of trust and the joint development of critique of current practice. While this raises tension it also builds generative communities of inquiry that can enhance both theory and practice. This paper reports on an Arts project undertaken in primary classrooms between university staff and generalist teacher co-researchers focusing on children’s idea development in dance, drama, music and art. This two year project is briefly outlined and some issues that arise in school research are explored. Project collaborators need to exercise caution in their examination of practice and strive to resist premature closure. All parties need to hold the tension of apparent contradictions, being both interested (in effective Arts pedagogy) and disinterested (in order to heighten perception) so that they might ‘surprise themselves in a landscape of practice with which many are very familiar indeed’ (McWilliam 2004:14). These issues and paradoxes in collaborative research are considered alongside some particular processes that build school and university partnerships

    Exploring children's development of ideas in music and dance

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    Eisner maintains that the Arts education community needs ‘empirically grounded examples of artistic thinking related to the nature of the tasks students engage in, the material with which they work, the context’s norms and the cues the teacher provides to advance their students’ thinking’ (2000:217). This paper reflects on preliminary results of a collaborative research project between teachers and university researchers that is investigating how children develop and refine arts-making ideas and related skills in Dance and Music in a small sample of schools in New Zealand. Factors such as the place of repetition in the development of ideas, the relevance of offers, the place of verbal and non-verbal communication in arts idea generation, and group work as an accepted ritual of practice, are explored and discussed

    Water ice in the Kuiper belt

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    We examine a large collection of low-resolution near-infrared spectra of Kuiper Belt objects (KBOs) and centaurs in an attempt to understand the presence of water ice in the Kuiper Belt. We find that water ice on the surface of these objects occurs in three separate manners: (1) Haumea family members uniquely show surfaces of nearly pure water ice, presumably a consequence of the fragmentation of the icy mantle of a larger differentiated proto-Haumea; (2) large objects with absolute magnitudes of H < 3 (and a limited number to H = 4.5) have surface coverings of water ice—perhaps mixed with ammonia—that appears to be related to possibly ancient cryovolcanism on these large objects; and (3) smaller KBOs and centaurs which are neither Haumea family members nor cold-classical KBOs appear to divide into two families (which we refer to as "neutral" and "red"), each of which is a mixture of a common nearly neutral component and either a slightly red or very red component that also includes water ice. A model suggesting that the difference between neutral and red objects due to formation in an early compact solar system either inside or outside, respectively, of the ~20 AU methanol evaporation line is supported by the observation that methanol is only detected on the reddest objects, which are those which would be expected to have the most of the methanol containing mixture

    Developing non-verbal ways of knowing in dance: Collaborative school / university action research.

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    Gardner (1983, 1993) has long argued that education privileges certain intelligences, primarily the linguistic and the logical-mathematical. As the arts tend to emphasise ways of knowing outside these intelligences, their marginalised status is exacerbated. A recent two-year project in eight primary schools on dance, drama, music and visual art found that the non-verbal aspects of each art form warranted serious attention to investigate what it means to learn in the arts. In this paper we describe and discuss the results of an aspect of action research in dance from this larger research project. We demonstrate how movement can be used as the primary expressive mode of communication, as opposed to privileging the spoken word. Through the use of powerpoint and video, we provide an intriguing and innovative model for providing non-verbal feedback and feed forward in the dance classroom

    Ground-based detection of a cloud of methanol from Enceladus: When is a biomarker not a biomarker?

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    Saturn's moon Enceladus has vents emerging from a sub-surface ocean, offering unique probes into the liquid environment. These vents drain into the larger neutral torus in orbit around Saturn. We present a methanol (CH3OH) detection observed with IRAM 30-m from 2008 along the line-of-sight through Saturn's E-ring. Additionally, we also present supporting observations from the Herschel public archive of water (ortho-H2O; 1669.9 GHz) from 2012 at a similar elongation and line-of-sight. The CH3OH 5(1,1)-4(1,1) transition was detected at 5.9 sigma confidence. The line has 0.43 km/s width and is offset by +8.1 km/s in the moon's reference frame. Radiative transfer models allow for gas cloud dimensions from 1750 km up to the telescope beam diameter ~73000 km. Taking into account the CH3OH lifetime against solar photodissociation and the redshifted line velocity, there are two possible explanations for the CH3OH emission: methanol is primarily a secondary product of chemical interactions within the neutral torus that (1) spreads outward throughout the E-ring or (2) originates from a compact, confined gas cloud lagging Enceladus by several km/s. We find either scenario to be consistent with significant redshifted H2O emission (4 sigma) measured from the Herschel public archive. The measured CH3OH:H2O abundance (> 0.5 per cent) significantly exceeds the observed abundance in the direct vicinity of the vents (~0.01 per cent), suggesting CH3OH is likely chemically processed within the gas cloud with methane (CH4) as its parent species.Comment: 16 pages, 4 figures, accepted for publication in the International Journal of Astrobiology (IJA

    Plasma Sterilization Technology for Spacecraft Applications

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    The application of plasma gas technology to sterilization and decontamination of spacecraft components is considered. Areas investigated include: effective sterilizing ranges of four separate gases; lethal constituents of a plasma environment; effectiveness of plasma against a diverse group of microorganisms; penetrating efficiency of plasmas for sterilization; and compatibility of spacecraft materials with plasma environments. Results demonstrated that plasma gas, specifically helium plasma, is a highly effective sterilant and is compatible with spacecraft materials
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