14,109 research outputs found

    Now the wars are over: The past, present and future of Scottish battlefields

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    Battlefield archaeology has provided a new way of appreciating historic battlefields. This paper provides a summary of the long history of warfare and conflict in Scotland which has given rise to a large number of battlefield sites. Recent moves to highlight the archaeological importance of these sites, in the form of Historic Scotland’s Battlefields Inventory are discussed, along with some of the problems associated with the preservation and management of these important cultural sites

    Experience with duplex bearings in narrow angle oscillating applications

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    Duplex ball bearings are matched pairs on which the abutting faces of the rings have been accurately ground so that when the rings are clamped together, a controlled amount of interference (preload) exists across the balls. These bearings are vulnerable to radial temperature gradients, blocking in oscillation and increased sensitivity to contamination. These conditions decrease the service life of these bearings. It was decided that an accelerated thermal vacuum life test should be conducted. The test apparatus and results are described and the rationale is presented for reducing a multiyear life test on oil lubricated bearings to less than a year

    Preliminary investigation of pressure influence on multiphase heat transfer report no. ii

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    Pressure and surface condition in multiphase boiling heat transfe

    Baby-Step Giant-Step Algorithms for the Symmetric Group

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    We study discrete logarithms in the setting of group actions. Suppose that GG is a group that acts on a set SS. When r,sSr,s \in S, a solution gGg \in G to rg=sr^g = s can be thought of as a kind of logarithm. In this paper, we study the case where G=SnG = S_n, and develop analogs to the Shanks baby-step / giant-step procedure for ordinary discrete logarithms. Specifically, we compute two sets A,BSnA, B \subseteq S_n such that every permutation of SnS_n can be written as a product abab of elements aAa \in A and bBb \in B. Our deterministic procedure is optimal up to constant factors, in the sense that AA and BB can be computed in optimal asymptotic complexity, and A|A| and B|B| are a small constant from n!\sqrt{n!} in size. We also analyze randomized "collision" algorithms for the same problem

    Review of deaths related to taking ecstasy, England and Wales, 1997-2000

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    Original article can be found at: http://www.bmj.com/archive/--Copyright BMJ Publishing Group Ltd DOI : 10.1136/bmj.326.7380.80Peer reviewe

    Labor Allocation and Productivity of Men and Women on Thai Farms

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    This paper examines the efficiency at labor allocation and the productivity of labor by gender between and within farm and non-farm enterprises on Thai farms. A Cobb-Douglas production function is estimated for both types of enterprises using disaggregated data. The estimated parameters of these functions are utilized to analyze efficiency and productivity issues. The results showed that inter-enterprise efficiency can be enhanced by allocating more labor of men to non-farm enterprises and mare labor of women to farm enterprises, but cultural constraints may impede such substitution. Policy makers need to improve incentives for non-farm enterprises

    Imaging Carrier Inhomogeneities in Ambipolar Tellurene Field Effect Transistors

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    Developing van der Waals (vdW) homojunction devices requires materials with narrow bandgaps and simultaneously high hole and electron mobilities for bipolar transport, as well as methods to image and study spatial variations in carrier type and associated conductivity with nanometer spatial resolution. Here we demonstrate the general capability of near-field scanning microwave microscopy (SMM) to image and study the local carrier type and associated conductivity in operando by studying ambiploar field effect transistors (FETs) of the 1D vdW material tellurium in 2D form. To quantitatively understand electronic variations across the device, we produce nanometer resolved maps of the local carrier equivalence backgate voltage. We show that the global device conductivity minimum determined from transport measurements does not arise from uniform carrier neutrality, but rather from the continued coexistence of p-type regions at the device edge and n-type regions in the interior of our micron-scale devices. This work both underscores and addresses the need to image and understand spatial variations in the electronic properties of nanoscale devices.Comment: 15 pages, 4 figure

    Biochemical and clinical response after umbilical cord blood transplant in a boy with early childhood-onset beta-mannosidosis.

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    BACKGROUND: Deficiency in the enzyme β-mannosidase was described over three decades ago. Although rare in occurrence, the presentation of childhood-onset β-mannosidase deficiency consists of hypotonia in the newborn period followed by global development delay, behavior problems, and intellectual disability. No effective pharmacologic treatments have been available. METHODS: We report 2-year outcomes following the first umbilical cord blood transplant in a 4-year-old boy with early childhood-onset disease. RESULTS: We show restoration of leukocyte β-mannosidase activity which remained normal at 2 years posttransplant, and a simultaneous increase in plasma β-mannosidase activity and dramatic decrease in urine-free oligosaccharides were also observed. MRI of the brain remained stable. Neurocognitive evaluation revealed test point gains, although the magnitude of improvement was less than expected for age, causing lower IQ scores that represent a wider developmental gap between the patient and unaffected peers. CONCLUSION: Our findings suggest that hematopoietic cell transplant can correct the biochemical defect in β-mannosidosis, although preservation of the neurocognitive trajectory may be a challenge
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