1,595 research outputs found

    Requirements for tracking radar for falling spheres

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    Error analysis on radar tracking of falling sphere

    On the non-persistence of Hamiltonian identity cycles

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    We study the leading term of the holonomy map of a perturbed plane polynomial Hamiltonian foliation. The non-vanishing of this term implies the non-persistence of the corresponding Hamiltonian identity cycle. We prove that this does happen for generic perturbations and cycles, as well for cycles which are commutators in Hamiltonian foliations of degree two. Our approach relies on the Chen's theory of iterated path integrals which we briefly resume.Comment: 17 page

    Dairy Cattle Handling Extension Programs: Training Workers and Cattle

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    Cattle handling Extension program educators often overlook the animal training component of efficient handling. The objectives of the study described in this article were to measure young dairy heifer behavioral responses toward handlers who received different types of training and to document whether repeated handling or time of day of handling affected heifer behavioral responses to handlers. Six handlers received training through a lecture, hands-on workshop, or video. An observer recorded heifer behavior during handling tests. The day and time of heifer training were most influential on heifer behavior, but heifer handling ease was improved when handlers had participated in the hands-on training

    Evidence-based planning and costing palliative care services for children : novel multi-method epidemiological and economic exemplar

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    Background: Children’s palliative care is a relatively new clinical specialty. Its nature is multi-dimensional and its delivery necessarily multi-professional. Numerous diverse public and not-for-profit organisations typically provide services and support. Because services are not centrally coordinated, they are provided in a manner that is inconsistent and incoherent. Since the first children’s hospice opened in 1982, the epidemiology of life-limiting conditions has changed with more children living longer, and many requiring transfer to adult services. Very little is known about the number of children living within any given geographical locality, costs of care, or experiences of children with ongoing palliative care needs and their families. We integrated evidence, and undertook and used novel methodological epidemiological work to develop the first evidence-based and costed commissioning exemplar. Methods: Multi-method epidemiological and economic exemplar from a health and not-for-profit organisation perspective, to estimate numbers of children under 19 years with life-limiting conditions, cost current services, determine child/parent care preferences, and cost choice of end-of-life care at home. Results: The exemplar locality (North Wales) had important gaps in service provision and the clinical network. The estimated annual total cost of current children’s palliative care was about £5.5 million; average annual care cost per child was £22,771 using 2007 prevalence estimates and £2,437- £11,045 using new 2012/13 population-based prevalence estimates. Using population-based prevalence, we estimate 2271 children with a life-limiting condition in the general exemplar population and around 501 children per year with ongoing palliative care needs in contact with hospital services. Around 24 children with a wide range of life-limiting conditions require end-of-life care per year. Choice of end-of-life care at home was requested, which is not currently universally available. We estimated a minimum (based on 1 week of end-of-life care) additional cost of £336,000 per year to provide end-of-life support at home. Were end-of-life care to span 4 weeks, the total annual additional costs increases to £536,500 (2010/11 prices). Conclusions: Findings make a significant contribution to population-based needs assessment and commissioning methodology in children’s palliative care. Further work is needed to determine with greater precision which children in the total population require access to services and when. Half of children who died 2002-7 did not have conditions that met the globally used children's palliative care condition categories, which need revision in light of findings

    Hemlock Woolly Adelgid in the Eastern United States: What Have We Learned?

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    Adelges tsugae (Hemlock Woolly Adelgid) is a small piercing-sucking insect that feeds on hemlock trees (Tsuga spp.). Native to Asia and the Pacific Northwest, the Hemlock Woolly Adelgid is invasive in the eastern United States where it attacks Tsuga canadensis (Eastern Hemlock) and T. caroliniana (Carolina Hemlock). It is currently found in 19 eastern states and has caused extensive mortality to hemlock forests. The ecological and economic impacts of this pest are significant, widespread, and often difficult to quantify. As the Hemlock Woolly Adelgid continues to disperse throughout the range of Eastern and Carolina Hemlocks, management techniques aimed at controlling it are being researched, implemented, and assessed. This introductory paper provides an overview of the biology, life cycle, ecology, and history of this pest in the eastern US as a foundation for this special issue

    Influence of HiPIMS pulse widths on the deposition behaviour and properties of CuAgZr compositionally graded films

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    In this work, the influence of different pulse widths (25, 50 and 100 μs) during high power impulse magnetron sputtering (HiPIMS) of copper, silver and zirconium was investigated in terms of plasma properties and properties of combinatorial composition gradient CuAgZr film libraries. In situ plasma diagnostics via optical emission spectroscopy (OES), time-of-flight mass spectrometry (TOFMS), and modified quartz crystal microbalance (m-QCM), followed by film ex situ X-ray diffraction (XRD) and scanning electron microscopy (SEM) investigations allowed to determine the effect of deposition parameters on the thin films' microstructural changes. Changing the pulse width, while keeping the duty cycle constant, modified the discharge composition in the target region and the ionised fraction of the sputtered species in the substrate region. The maximum Cu ionised fraction (19 %) was found for 50 μs, resulting in compact and smooth morphology for Cu-rich films, whereas short 25 μs pulses provided porous columnar films with rough surfaces, as the result from Ar+ bombardment. For Ag-rich films, Ag segregation allowed the deposition of dense layers, regardless of the used pulse width. Furthermore, low Ag (<10 at.%) CuAgZr films produced via HiPIMS and direct-current magnetron sputtering (DCMS) were compared in terms of structural and mechanical property changes as a function of Zr contents. For the studied chemical composition range, a linear relationship between Zr content, XRD phase shift and mechanical properties was observed for HiPIMS films, in contrast to DCMS's more abrupt transitions. An increase in hardness and elastic modulus (up to 44 % and 22 %, respectively) was found for the HiPIMS films compared to DCMS ones. The obtained results highlight HiPIMS's flexibility in providing a wide range of tailoring possibilities to meet specific application requirements, such as crystalline microstructure, density and associated mechanical properties

    VFDB 2008 release: an enhanced web-based resource for comparative pathogenomics

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    Virulence factor database (VFDB) was set up in 2004 dedicated for providing current knowledge of virulence factors (VFs) from various medical significant bacterial pathogens to facilitate pathogenomic research. Nowadays, complete genome sequences of almost all the major pathogenic microbes have been determined, which makes comparative genomics a powerful approach for uncovering novel virulence determinants and hidden aspects of pathogenesis. VFDB was therefore upgraded to present the enormous diversity of bacterial genomes in terms of virulence genes and their organization. The VFDB 2008 release includes the following new features; (i) detailed tabular comparison of virulence composition of a given genome with other genomes of the same genus, (ii) multiple alignments and statistical analysis of homologous VFs and (iii) graphical comparison of genomic organizations of virulence genes. Comparative analysis of the numerous VFs will improve our understanding of the nature and evolution of virulence, as well as the development of new therapeutic and preventive strategies. VFDB 2008 release offers more user-friendly tools for comparative pathogenomics and it is publicly accessible at http://www.mgc.ac.cn/VFs/
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