11,630 research outputs found

    An alternative wind profile formulation for urban areas in neutral conditions

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    On the basis of meteorological observations conducted within the city of Rome, Italy, a new formulation of the wind-speed profile valid in urban areas and neutral conditions is developed. It is found that the role played by the roughness length in the canonical log-law profile can be taken by a local length scale, depending on both the surface cover and the distance above the ground surface, which follows a pattern of exponential decrease with height. The results show that the proposed model leads to increased performance compared with that obtained by using other approaches found in the literature

    Collections for people: museums' stored collections as a public resource

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    Collections in UK museums grew enormously in the latter half of the 20th century yet museum collections, mostly maintained at public expense, are perceived as an underused resource. The Museums Association’s 2005 report, Collections for the Future1, together with press comments and books such as Treasures on Earth (2002)2 and Fragments of the World (2005)3, brought this issue into sharp focus. Collections for People set out to understand the scale of museum stored collections, and the main parameters of their access and use: • What is the size and nature of collections as a resource? How are they distributed, geographically and among different types of museum? • How much are different types of collection used by people other than museum staff? What sort of people use collections? What do they use them for: research, teaching and learning, creative activities, visits for enjoyment such as store tours? • How do users perceive this service? Do museums actively market collections access? Do they publicise what is in their collections? • How do museums facilitate collections use? What are the factors associated with greater use of collections? What do museums see as the barriers to more use

    The use of ultrasound in clinical setting for children affected by NAFLD. is it safe and accurate?

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    Non-alcoholic fatty liver disease (NAFLD) has become over the last decade the most common form of chronic liver disease in children and adults. Thus, establishing the diagnosis of NAFLD is of utmost importance and represents a major challenge as the disease is generally silent and the current gold standard for diagnosis is an invasive liver biopsy, a procedure that is not suitable for screening purposes. Many non-invasive diagnostic tools have been evaluated so far. Recently the utility of ultrasonography for non-invasive diagnosis and estimation of hepatic steatosis has been demonstrated in a large prospective pediatric study

    Adiabatic Evolution for Systems with Infinitely many Eigenvalue Crossings

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    We formulate an adiabatic theorem adapted to models that present an instantaneous eigenvalue experiencing an infinite number of crossings with the rest of the spectrum. We give an upper bound on the leading correction terms with respect to the adiabatic limit. The result requires only differentiability of the considered spectral projector, and some geometric hypothesis on the local behaviour of the eigenvalues at the crossings

    Jaime Alvar - José María Blázquez (eds.) Héroes y antihéroes de la Antigüedad Clásica. Madrid, Edic. Cátedra, 1997, 332 pp. I.S.B.N.: 84-376-1505-4.

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    Fil: Monti, Gabriela A.

    Effects of Marangoni numbers on thermocapillary drop migration: constant for quasi-steady state?

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    The overall {\it steady}-state energy balance with two phases in a flow domain requires that the change in energy of the domain is equal to the difference between the total energy entering the domain and that leaving the domain. From the condition, the integral thermal flux across the surface is studied for a {\it steady} thermocapillary drop migration in a flow field with uniform temperature gradient at small and large Marangoni (Reynolds) numbers. The drop is assumed to have only a slight axisymmetric deformation from a sphere. It is identified that a conservative/nonconservative integral thermal flux across the surface in the {\it steady} thermocapillary drop migration at small/large Marangoni (Reynolds) numbers. The conservative flux confirms the assumption of {\it quasi-steady} state in the thermocapillary drop migration at small Marangoni (Reynolds) numbers. The nonconservative flux may well result from the invalid assumption of {\it quasi-steady} state, which indicates that the thermocapillary drop migration at large Marangoni (Reynolds) numbers cannot reach {\it steady} state and is thus a {\it unsteady} process.Comment: 21 pages. arXiv admin note: text overlap with arXiv:1112.276
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