3,603 research outputs found

    Active cloaking of finite defects for flexural waves in elastic plates

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    We present a new method to create an active cloak for a rigid inclusion in a thin plate, and analyse flexural waves within such a plate governed by the Kirchhoff plate equation. We consider scattering of both a plane wave and a cylindrical wave by a single clamped inclusion of circular shape. In order to cloak the inclusion, we place control sources at small distances from the scatterer and choose their intensities to eliminate propagating orders of the scattered wave, thus reconstructing the respective incident wave. We then vary the number and position of the control sources to obtain the most effective configuration for cloaking the circular inclusion. Finally, we successfully cloak an arbitrarily shaped scatterer in a thin plate by deriving a semi-analytical, asymptotic algorithm.Comment: 19 pages, 14 figures, 1 tabl

    The spatial sensitivity of the spectral diversity–biodiversity relationship: an experimental test in a prairie grassland

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    Remote sensing has been used to detect plant biodiversity in a range of ecosystems based on the varying spectral properties of different species or functional groups. However, the most appropriate spatial resolution necessary to detect diversity remains unclear. At coarse resolution, differences among spectral patterns may be too weak to detect. In contrast, at fine resolution, redundant information may be introduced. To explore the effect of spatial resolution, we studied the scale dependence of spectral diversity in a prairie ecosystem experiment at Cedar Creek Ecosystem Science Reserve, Minnesota, USA. Our study involved a scaling exercise comparing synthetic pixels resampled from high-resolution images within manipulated diversity treatments. Hyperspectral data were collected using several instruments on both ground and airborne platforms. We used the coefficient of variation (CV) of spectral reflectance in space as the indicator of spectral diversity and then compared CV at different scales ranging from 1 mm2 to 1 m2 to conventional biodiversity metrics, including species richness, Shannon’s index, Simpson’s index, phylogenetic species variation, and phylogenetic species evenness. In this study, higher species richness plots generally had higher CV. CV showed higher correlations with Shannon’s index and Simpson’s index than did species richness alone, indicating evenness contributed to the spectral diversity. Correlations with species richness and Simpson’s index were generally higher than with phylogenetic species variation and evenness measured at comparable spatial scales, indicating weaker relationships between spectral diversity and phylogenetic diversity metrics than with species diversity metrics. High resolution imaging spectrometer data (1 mm2 pixels) showed the highest sensitivity to diversity level. With decreasing spatial resolution, the difference in CV between diversity levels decreased and greatly reduced the optical detectability of biodiversity. The optimal pixel size for distinguishing a diversity in these prairie plots appeared to be around 1 mm to 10 cm, a spatial scale similar to the size of an individual herbaceous plant. These results indicate a strong scaledependence of the spectral diversity-biodiversity relationships, with spectral diversity best able to detect a combination of species richness and evenness, and more weakly detecting phylogenetic diversity. These findings can be used to guide airborne studies of biodiversity and develop more effective large-scale biodiversity sampling methods

    Demography and disorders of the French Bulldog population under primary veterinary care in the UK in 2013

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    Abstract Background Despite its Gallic name, the French Bulldog is a breed of both British and French origin that was first recognised by The Kennel Club in 1906. The French Bulldog has demonstrated recent rapid rises in Kennel Club registrations and is now (2017) the second most commonly registered pedigree breed in the UK. However, the breed has been reported to be predisposed to several disorders including ocular, respiratory, neurological and dermatological problems. The VetCompassℱ Programme collates de-identified clinical data from primary-care veterinary practices in the UK for epidemiological research. Using VetCompassℱ clinical data, this study aimed to characterise the demography and common disorders of the general population of French Bulldogs under veterinary care in the UK. Results French Bulldogs comprised 2228 (0.49%) of 445,557 study dogs under veterinary care during 2013. Annual proportional birth rates showed that the proportional ownership of French Bulldog puppies rose steeply from 0.02% of the annual birth cohort attending VetCompassℱ practices in 2003 to 1.46% in 2013. The median age of the French Bulldogs overall was 1.3 years (IQR 0.6–2.5, range 0.0–13.0). The most common colours of French Bulldogs were brindle (solid or main) (32.36%) and fawn (solid or main) (29.9%). Of the 2228 French Bulldogs under veterinary care during 2013, 1612 (72.4%) had at least one disorder recorded. The most prevalent fine-level precision disorders recorded were otitis externa (14.0%, 95% CI: 12.6–15.5), diarrhoea (7.5%, 95% CI: 6.4–8.7), conjunctivitis (3.2%, 95% CI: 2.5–4.0), nails overlong (3.1%, 95% CI% 2.4–3.9) and skin fold dermatitis (3.0%, 95% CI% 2.3–3.8). The most prevalent disorder groups were cutaneous (17.9%, 95% CI: 16.3–19.6), enteropathy (16.7%, 95% CI: 15.2–18.3), aural (16.3%, 95% CI: 14.8–17.9), upper respiratory tract (12.7%, 95% CI: 11.3–14.1) and ophthalmological (10.5%, 95% CI: 9.3–11.9). Conclusions Ownership of French Bulldogs in the UK is rising steeply. This means that the disorder profiles reported in this study reflect a current young UK population and are likely to shift as this cohort ages. Otitis externa, diarrhoea and conjunctivitis were the most common disorders in French Bulldogs. Identification of health priorities based on VetCompassℱ data can support evidence–based reforms to improve health and welfare within the breed

    Children's informal learning at home during COVID-19 lockdown

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    The national COVID-19 lockdown during school Term 1 2020 provided a unique context to investigate children’s experiences of informal, everyday learning in their household bubble. In Terms 3 and 4, 178 children in Years 4–8 from 10 primary schools agreed to participate in a group art-making activity and an individual interview about their experiences. The research adopted a strengths-based approach on the basis that most children are capable actors in their social worlds. This report documents children’s accounts of the multiple ways in which they negotiated the novel experience of forced confinement over a period of several weeks with family and whānau. The report is rich with children’s own accounts of their everyday living and learning during lockdown. To foreground children’s descriptions and explanations of their lockdown experience in this way is an acknowledgement of their right to express their views on matters of interest to them in their lives, and to have those views listened to, and acted on, by adults. Similarly, the approach reflects a growing educational research interest in student voice: enabling children to articulate their experiences so that adults can use this knowledge to better respond to and support children’s learning aspirations and needs. This research report does not speak for all children or all children’s experiences. Nevertheless, it does provide valuable insights about the phenomenon of children’s informal and everyday learning during lockdown, gained from a group of children for whom it was a mostly positive experience, and through which they learned much about themselves as persons and as members of a family and whānau. Several months after the event, children in this study were able and willing to recall their experiences of learning during lockdown. They could identify social, cultural, and historical dimensions of their learning at home. Some children were able to recount rich, detailed stories about their lockdown experience and the ways in which they organised their days and activities. For some others, their days were largely shaped for them by family and whānau members, but even so, the children were able to explain what they enjoyed, or did not, and why. Variations in children’s learning across the group highlighted the complexity of learning that each child experienced, and the importance of having social relations, environments, and contexts that encourage and support their learning. Children demonstrated an understanding and appreciation of the value of this learning.falsehttp://www.nzcer.org.nz/research/publications/learning-during-lockdownNew Zealand Council for Educational Researc

    Radiation Test Results on COTS and non-COTS Electronic Devices for NASA-JSC Space Flight Projects

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    This presentation reports the results of recent proton and heavy ion Single Event Effect (SEE) testing on a variety of COTS and non-COTs electronic devices and assemblies tested for the Space Shuttle, International Space Station (ISS) and Multi-Purpose Crew Vehicle (MPCV)

    Identification of novel pesticides for use against glasshouse invertebrate pests in UK tomatoes and peppers

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    To inform current and future pesticide availability to glasshouse vegetable growers, the current project trialled more than twenty products, including existing industry standards, against four key pests of glasshouse tomatoes and bell peppers. These included experimental conventional chemical pesticides as well as alternative biopesticide and biorational products based on phytochemicals, microbials and physically-acting substances. The results suggest that certain biopesticide products, particularly botanicals, provide good levels of pest control, with the same being true of experimental conventional chemical pesticides not yet recommended for use against these pests on these crops. Efforts are on-going to ensure that results of the current project translate to industry benefit via new pesticide approvals

    Extremity and excess : proceedings of the 2011 University of Salford College of Arts and Social Sciences postgraduate research conference

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    The essays gathered in this volume explore the difficulties of classifying and conceptualizing the extreme and the excessive. Uniting a broad selection of new research (initially presented as part of the University of Salford’s annual College of Arts and Social Sciences Conference 2011), the collection queries some of the premises surrounding these topics: ideas that are most often presented as a counterpoint to a perceived ‘normality’. Both terrorism/responses to terrorist threat and the grotesque within horror cinema are represented whilst perhaps reflecting that which is deemed outside of the general parameters of acceptability and decency. Yet there is also a focus on subjects that may, at first, be seen as less radical. From alternative representations of authorship to new technology’s attempts at ‘realness’, prose as hysteria through to melodramatic depictions of war and, finally, approaches that aim to challenge the more commonplace critical strategies employed in the assessment of both fine art and fine artists, this collection will be of particular interest to students and scholars prepared to look beyond a concept that may hint at the merely shocking and engage with a more widely interpreted and nuanced critique of extremity and excess

    estudo da opinião dos médicos e implicaçÔes para o futuro

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    INTRODUCTION: The COVID-19 pandemic led to the reorganization of healthcare services and teleconsultation emerged as a solution to facilitate patient appointments. The aim of this study was to characterize, from a physician perspective, the teleconsultations carried out in the Portuguese National Health Service (SNS) during the first phase of the pandemic and to identify factors that influence the experience of the teleconsultation. MATERIAL AND METHODS: A cross-sectional analytical study was conducted based on an online survey, between July-September 2020, aimed at SNS doctors. Data on demographics, practice, attitudes and perceptions associated with the teleconsultation was collected. The adjusted prevalence ratio (aPR) was calculated to identify demographic factors and determinants of teleconsultation associated with satisfaction, use of video calls and greater motivation to carry out teleconsultations in the future. RESULTS: 2225 valid responses were obtained. Teleconsultation was carried out by 93.8% of participants in this period, 99.0% used the telephone as a form of communication and only 8.0% used a video call. A high degree of satisfaction with the teleconsultation was significantly associated with perceiving the teleconsultation as providing care with equivalent quality to a face-to-face consultation (aPR = 1.472) and being motivated to do teleconsultation after the pandemic (aPR = 4.081). Reporting clinical (aPR = 0.763) or technical difficulties (aPR = 0.666) was negatively associated with satisfaction). 70.4% of doctors would like to continue doing follow-up teleconsultations and 53.3% consider that video call technologies should always or often be used during teleconsultations. CONCLUSION: Teleconsultation seems to have potential to to become a common practice in the future. However, it is important to address clinical, technical, organizational, and legal questions and, above all, to ensure that it is a safe and valuable practice for patients.publishersversionepub_ahead_of_prin

    Generalized observers and velocity measurements in General Relativity

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    To resolve some unphysical interpretations related to velocity measurements by static observers, we discuss the use of generalized observer sets, give a prescription for defining the speed of test particles relative to those observers and show that, for any locally inertial frame, the speed of a freely falling material particle is always less than the speed of light at the Schwarzschild black hole surface.Comment: 20 pages, 1 figure, submitted to General Relativity and Gravitatio
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