1,145 research outputs found

    Structural metamaterial lattices by laser powder-bed fusion of 17-4PH steel

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    Additive manufacturing build parameters are used to engineer structural metamaterials lattices with controllable mechanical performance, achieved through microstructural grading of 17-4PH steel without compositional or geometric modification. The high solidification rates of laser powder-bed fusion suppress the thermal martensitic transformation and lead to elevated levels of retained austenite. Diamond cubic lattices built at low energy density (low thermal strain) retain a low martensite phase fraction (3 wt%) and exhibit a bend-dominated compression response. Lattices built at high energy density experience increased thermal strain during the build, causing in-situ deformation-driven transformation, yielding 44 wt% martensite; these exhibit a stretch-dominated compression response. Metamaterial lattices, with high and low energy density parameters in different configurations, exhibit mixed compression responses. Controllable mechanical response was achieved through control of microstructure, using build parameters to adjust thermal strain and selectively suppress or trigger the martensitic phase transformation in-situ

    Fishing the georges river: Cultural diversity and urban environments

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    The Georges River runs through the heart of Sydney’s most culturally diverse population, including long-established Aboriginal and Anglo-Celtic communities as well as the many more recent immigrant communities that have developed since the 1980s. Most people in all these communities are in working-class employment (if they have jobs at all), are living in densely packed suburbs and, despite some gentrification on the margins, still have significant disadvantages in educational and social infrastructure. As well as being a large river with scenic parklands threading along its lower estuarine reaches, the Georges River is also the focus of intensifying ethnic conflicts which often spill over into the media. The names of the river’s suburbs – Cabramatta, Liverpool, Bankstown, Macquarie Fields and Lakemba – are well known around Australia for their tensions. Yet, recent surveys of Australian attitudes to cultural diversity have demonstrated a widespread endorsement of the desire to reach across cultural differences despite the effect of international events and the media in increasing the hostile polarisation between ethnic groups (Ang et al. 2002, 2006). This paper will ask whether considering the area’s complex relationships and tensions through the lens of ‘everyday’ activities might allow us to understand those conflicts more clearly

    Thermodynamic Signature of a Two-Dimensional Metal-Insulator Transition

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    We present a study of the compressibility, K, of a two-dimensional hole system which exhibits a metal-insulator phase transition at zero magnetic field. It has been observed that dK/dp changes sign at the critical density for the metal-insulator transition. Measurements also indicate that the insulating phase is incompressible for all values of B. Finally, we show how the phase transition evolves as the magnetic field is varied and construct a phase diagram in the density-magnetic field plane for this system.Comment: 4 pages, 4 figures, submitted to Physical Review Letters; version 1 is identical to version 2 but didn't compile properl

    On equal temperament

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    In this article, I use Stengers’ (2010) concepts of ‘factish’, ‘requirements’ and ‘obligations’, as well as Latour’s (1993) critique of modernity, to interrogate the rise of Equal Temperament as the dominant system of tuning for western music. I argue that Equal Temperament is founded on an unacknowledged compromise which undermines its claims to rationality and universality. This compromise rests on the standardization which is the hallmark of the tuning system of Equal Temperament, and, in this way, it is emblematic of Latour’s definition of modernity. I further argue that the problem of the tuning of musical instruments is one which epitomizes the modern distinction between the natural and the social. In turn, this bears witness to what Whitehead calls the ‘bifurcation of nature’. Throughout this article, using the work of Stengers and Latour, I seek to use tuning as a case study which allows social research to talk both of the natural and of the social aspects of music and tuning, without recourse to essentialism or simple social construction. In this way, my argument seeks to avoid bifurcating nature

    Generalized partially linear models on Riemannian manifolds

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    We introduce generalized partially linear models with covariates on Riemannian manifolds. These models, like ordinary generalized linear models, are a generalization of partially linear models on Riemannian manifolds that allow for scalar response variables with error distribution models other than a normal distribution. Partially linear models are particularly useful when some of the covariates of the model are elements of a Riemannian manifold, because the curvature of these spaces makes it difficult to define parametric models. The model was developed to address an interesting application: the prediction of children's garment fit based on three‐dimensional scanning of their bodies. For this reason, we focus on logistic and ordinal models and on the important and difficult case where the Riemannian manifold is the three‐dimensional case of Kendall's shape space. An experimental study with a well‐known three‐dimensional database is carried out to check the goodness of the procedure. Finally, it is applied to a three‐dimensional database obtained from an anthropometric survey of the Spanish child population. A comparative study with related techniques is carried out

    Understanding signaling cascades in melanoma

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    Understanding regulatory pathways involved in melanoma development and progression has advanced significantly in recent years. It is now appreciated that melanoma is the result of complex changes in multiple signaling pathways that affect growth control, metabolism, motility and the ability to escape cell death programs. Here we review the major signaling pathways currently known to be deregulated in melanoma with an implication to its development and progression. Among these pathways are Ras, B-Raf, MEK, PTEN, phosphatidylinositol-3 kinase (PI3Ks) and Akt which are constitutively activated in a significant number of melanoma tumors, in most cases due to genomic change. Other pathways discussed in this review include the [Janus kinase/signal transducer and activator of transcription (JAK/STAT), transforming growth factor-beta pathways which are also activated in melanoma, although the underlying mechanism is not yet clear. As a paradigm for remodeled signaling pathways, melanoma also offers a unique opportunity for targeted drug development.Fil: Lopez Bergami, Pablo Roberto. Sanford-burnham Medical Research Institute; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Fitchmann, B. Sanford-burnham Medical Research Institute; Estados UnidosFil: Ronai, Ze´ev. Sanford-burnham Medical Research Institute; Estados Unido

    The assessment of neuromuscular fatigue during 120 min of simulated soccer exercise

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    Purpose This investigation examined the development of neuromuscular fatigue during a simulated soccer match incorporating a period of extra time (ET) and the reliability of these responses on repeated test occasions. Methods Ten male amateur football players completed a 120 min soccer match simulation (SMS). Before, at half time (HT), full time (FT), and following a period of ET, twitch responses to supramaximal femoral nerve and transcranial magnetic stimulation (TMS) were obtained from the knee-extensors to measure neuromuscular fatigue. Within 7 days of the first SMS, a second 120 min SMS was performed by eight of the original ten participants to assess the reliability of the fatigue response. Results At HT, FT, and ET, reductions in maximal voluntary force (MVC; −11, −20 and −27%, respectively, P ≤ 0.01), potentiated twitch force (−15, −23 and −23%, respectively, P < 0.05), voluntary activation (FT, −15 and ET, −18%, P ≤ 0.01), and voluntary activation measured with TMS (−11, −15 and −17%, respectively, P ≤ 0.01) were evident. The fatigue response was robust across both trials; the change in MVC at each time point demonstrated a good level of reliability (CV range 6–11%; ICC2,1 0.83–0.94), whilst the responses identified with motor nerve stimulation showed a moderate level of reliability (CV range 5–18%; ICC2,1 0.63–0.89) and the data obtained with motor cortex stimulation showed an excellent level of reliability (CV range 3–6%; ICC2,1 0.90–0.98). Conclusion Simulated soccer exercise induces a significant level of fatigue, which is consistent on repeat tests, and involves both central and peripheral mechanisms

    Broad clinical phenotypes associated with TAR-DNA binding protein (TARDBP) mutations in amyotrophic lateral sclerosis

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    The finding of TDP-43 as a major component of ubiquitinated protein inclusions in amyotrophic lateral sclerosis (ALS) has led to the identification of 30 mutations in the transactive response-DNA binding protein (TARDBP) gene, encoding TDP-43. All but one are in exon 6, which encodes the glycine-rich domain. The aim of this study was to determine the frequency of TARDBP mutations in a large cohort of motor neurone disease patients from Northern England (42 non-superoxide dismutase 1 (SOD1) familial ALS (FALS), nine ALS-frontotemporal dementia, 474 sporadic ALS (SALS), 45 progressive muscular atrophy cases). We identified four mutations, two of which were novel, in two familial (FALS) and two sporadic (SALS) cases, giving a frequency of TARDBP mutations in non-SOD1 FALS of 5% and SALS of 0.4%. Analysis of clinical data identified that patients had typical ALS, with limb or bulbar onset, and showed considerable variation in age of onset and rapidity of disease course. However, all cases had an absence of clinically overt cognitive dysfunction

    Barriers to and enablers of sustainable practices: insights from ethnic minority migrants

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    Migration from the Global South to Global North is a major feature of contemporary population movements, and provides a lived experiment of the implications of moving from less resource-intensive modes of living towards more resource-intensive ones. Pre-migration practices come together in complex ways post-migration with established norms and infrastructures in destination countries. Here we examine the barriers to and enablers of sustainable practices, synthesising in-depth research from nine different studies in south-eastern Australia in relation to household water use, food growing and transport. The total sample includes 323 migrants from 33 countries. The main barriers include infrastructure and broader patterns of work and society. The main enablers are cultural norms of frugality and preferences for public transport. Barriers and enablers interact in diverse ways. We show that migrants are important contributors to inadvertent sustainabilities, but their contributions may be weakened by infrastructural, structural and cultural barriers. Addressing the diverse capacities of migrants would enhance system change for everyone
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