10,578 research outputs found

    Are Radio Pulsars Strange Stars ?

    Full text link
    A remarkably precise observational relation for pulse core component widths of radio pulsars is used to derive stringent limits on pulsar radii, strongly indicating that pulsars are strange stars rather than neutron stars. This is achieved by inclusion of general relativistic effects due to the pulsar mass on the size of the emission region needed to explain the observed pulse widths, which constrain the pulsar masses to be less than 2.5 Solar masses and radii to be smaller than 10.5 km.Comment: v.2 : 12 pages including 3 figures and 2 tables, LaTex, uses epsfig. This version has one extra figure, few lines of new text and typos fixe

    Four Stokes parameter radio frequency polarimetry of a flare from AD Leonis

    Get PDF
    Observations of the four Stokes parameters of a 430 MHz flare from the UV Ceti-type star AD Leonis are presented. The maximum amplitude of the event was 0.52 flux units and the durations at one-half and one-tenth maximum were 12 and 40 seconds, respectively. The degree of circular polarization at maximum intensity was approximately 56 percent and was later observed to be as high as 92 percent. Linear polarization was also observed at a level of about 21 percent at flare maximum which allowed an upper limit of 440 radians - sq m to be placed on the rotation measure

    A preliminary case study of the effect of shoe-wearing on the biomechanics of a horse’s foot

    Get PDF
    Horse racing is a multi-billion-dollar industry that has raised welfare concerns due to injured and euthanized animals. Whilst the cause of musculoskeletal injuries that lead to horse morbidity and mortality is multifactorial, pre-existing pathologies, increased speeds and substrate of the racecourse are likely contributors to foot disease. Horse hooves have the ability to naturally deform during locomotion and dissipate locomotor stresses, yet farriery approaches are utilised to increase performance and protect hooves from wear. Previous studies have assessed the effect of different shoe designs on locomotor performance; however, no biomechanical study has hitherto measured the effect of horseshoes on the stresses of the foot skeleton in vivo. This preliminary study introduces a novel methodology combining three-dimensional data from biplanar radiography with inverse dynamics methods and finite element analysis (FEA) to evaluate the effect of a stainless steel shoe on the function of a Thoroughbred horse's forefoot during walking. Our preliminary results suggest that the stainless steel shoe shifts craniocaudal, mediolateral and vertical GRFs at mid-stance. We document a similar pattern of flexion-extension in the PIP (pastern) and DIP (coffin) joints between the unshod and shod conditions, with slight variation in rotation angles throughout the stance phase. For both conditions, the PIP and DIP joints begin in a flexed posture and extend over the entire stance phase. At mid-stance, small differences in joint angle are observed in the PIP joint, with the shod condition being more extended than the unshod horse, whereas the DIP joint is extended more in the unshod than the shod condition. We also document that the DIP joint extends more than the PIP after midstance and until the end of the stance in both conditions. Our FEA analysis, conducted solely on the bones, shows increased von Mises and Maximum principal stresses on the forefoot phalanges in the shod condition at mid-stance, consistent with the tentative conclusion that a steel shoe might increase mechanical loading. However, because of our limited sample size none of these apparent differences have been tested for statistical significance. Our preliminary study illustrates how the shoe may influence the dynamics and mechanics of a Thoroughbred horse's forefoot during slow walking, but more research is needed to quantify the effect of the shoe on the equine forefoot during the whole stance phase, at faster speeds/gaits and with more individuals as well as with a similar focus on the hind feet. We anticipate that our preliminary analysis using advanced methodological approaches will pave the way for new directions in research on the form/function relationship of the equine foot, with the ultimate goal to minimise foot injuries and improve animal health and welfare

    Anti-racist social work in a 'post-race society'? Interrogating the amorphous 'other'

    Get PDF
    Anti-racist social work is at a crossroads: while on the one hand, racial binaries such as black/white, us/other and slave/master can be useful political tools to understand institutional racism, current contexts of multiculturalism raise questions about the continued relevance of race as a category for analysis. 'Newer' forms of racialised identities are emerging that need to be incorporated into a broader conceptualisation of non-colour-based race theory. In this article, these contradictions are explicated through a phenomenological study of embodied reflections on race, ethnicity and self-identity among social work students. Frantz Fanon's 'fact of blackness' provides an epistemic guide to this phenomenological study, providing a multi-layered examination of social work students' experiential accounts of their embodied identities, their colour, race, blackness, whiteness and sexuality and what this means for self-identity. Tentative student discourses provide powerful insights into the urgent need for a radical turn in (re)locating culture and race studies in the social work curriculum

    Is there a close association between "soils" and "vegetation"? : A case study from central western New South Wales

    Get PDF
    The assumption that ‘soils’ and ‘vegetation’ are closely associated was tested by describing soils and vegetation along a Travelling Stock Reserve west of Grenfell, New South Wales (lat 33° 55’S, long 147° 45’E). The transect was selected on the basis of (a) minimising the effects of non-soil factors (human interference, climate and relief) on vegetation and (b) the presence of various soil and vegetation types as indicated by previous mapping. ‘Soils’ were considered at three levels: soil landscapes (a broad mapping unit widely used in central western NSW), soil types (according to a range of classifications) and soil properties (depth, pH, etc.). ‘Vegetation’ was considered in three ways: vegetation type (in various classifications), density/floristic indices (density of woody species, abundance of native species, etc.) and presence/absence of individual species. Sites along the transect were grouped according to soil landscapes or soil types and compared to vegetation types or indices recorded at the sites. Various measures indicated low associations between vegetation types and soil landscapes or soil types. Except for infrequent occurrences of a soil type or landscape, any one soil type or landscape was commonly associated with a number of vegetation types and any one vegetation type was associated with a number of soil landscapes or soil types. However, significant associations between some vegetation indices, mainly density or numbers of woody species, and some soil landscapes and soil types were evident. Although many species were relatively ubiquitous, some groups of species that were restricted to one or two soil types were identified. Canonical Correspondence Analysis provided some suggestions as to which properties (e.g. texture) of these soils were associated with the presence of particular species

    The Effects of Simultaneous Prompting and Instructive Feedback For Individuals with Autism

    Get PDF
    Autism Spectrum Disorder (ASD) is a developmental delay characterized by significant impairment in many areas including: social communication, academic, occupational, and activities of daily living. The Individuals with Disabilities Education Act (IDEA) mandates that educators use evidence-based practices (EBPs) with individuals receiving special education services. In addition to EBPs, educators should provide the most efficient instruction possible. This study examines the efficacy of two EBPs on the acquisition of spoken category names (i.e., fruit, nut, vegetable, herb): (1) simultaneous prompting – a prompt-fading procedure, and (2) instructive feedback (IF) – a technique in which additional stimuli are presented during a learning trial. IF stimuli (i.e., spoken category names) were presented during listener discrimination training using simultaneous prompting. A multiple-probe single case design was used across three categories and replicated across five participants with ASD. Results indicate that the intervention was effective for Category 1, but was ineffective for subsequent categories, for four participants. The intervention was ineffective for the remaining participant. These findings suggest simultaneous prompting and IF may be effective for individuals with ASD; however, further research is needed to explore how to maintain effectiveness across additional target categories

    Four rural cemeteries in central western NSW: Islands of Australiana in a European sea?

    Get PDF
    Vascular plants present in groundstoreys of variously–managed areas in four cemeteries in central western NSW – two on the Central Western Slopes (Garra and Toogong) and two on the Central Tablelands (Lyndhurst and Carcoar) – were recorded over periods of 6–10 years. It was hypothesised that (a) areas of the cemeteries with a history of nil or low disturbance would represent high quality remnant vegetation (i.e. contain a diversity of native species but few naturalised species), and (b) that clearing of woody vegetation, together with similar management (e.g. regular mowing) would result in homogenisation of the groundstoreys such that many species, native and naturalised, would be common to all sites. 344 species (176 native, 154 naturalised and 14 non–naturalised exotics) were recorded across the four cemeteries. Many native species that were rare in the surrounding agricultural lands were present in the cemeteries (enhancing their value as conservation areas) but no cemetery contained areas of groundstorey that would qualify as ‘pristine’. Across all management areas, the proportions of naturalised species in the native + naturalised floras of the cemeteries ranged from 46 to 55 %. Though never dominant, naturalised species also comprised high proportions (42 to 51 %) of the floras of the least disturbed (nil or infrequently mown) areas within each cemetery. Many (40 %) of the species recorded occurred at only one cemetery. This partly explained why the floras of similarly– managed parts of cemeteries on the Central Western Slopes were, contrary to expectations, markedly different to those on the Central Tablelands. However, within the same botanic subdivision, floras – particularly of naturalised species in regularly mown grasslands – were more similar (‘homogenised’) than those of nil or infrequently mown grasslands

    Physical Measurements with the Valve Ultra-Micrometer

    Get PDF
    corecore