771 research outputs found

    Representing multifunctional cities: density and diversity in space and time

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    In this paper, we define measures of urban diversity, density and segregation using newdata and software systems based on GIS. These allow us to visualise the meaning of themultifunctional city. We begin with a discussion of how cities have become moresegregated in their land uses and activities during the last 200 years and how the currentfocus is on reversing this trend through limiting urban sprawl and bringing new lifeback to the inner and central city. We define various indices which show how diversityand density manifest themselves spatially. We argue that multifunctionalism is a relativeconcept, dependent upon the spatial and temporal scale that we use to think about themixing and concentration of urban land uses. We present three examples using spatiallysmoothed indicators of diversity: for a world city ? London, for a highly controlledpolycentric urban region ? Randstad Holland, and for a much more diffusely populatedsemi-urban region ? Venice-Padua-Teviso. We conclude by illustrating that urbandiversity varies as people engage in different activities associated with different landuses throughout the day, as well as through the vertical, third dimension of the city. Thisimpresses the point that we need to understand multifunctional cities in all theirdimensions of space and time

    Suppression of spin-torque in current perpendicular to the plane spin-valves by addition of Dy cap layers

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    We demonstrate that the addition of Dy capping layers in current perpendicular to the plane giant magneto-resistive spin-valves can increase the critical current density beyond which spin-torque induced instabilities are observed by about a factor of three. Current densities as high as 5e7 A/cm2 are measured provided that the electron current flows from the free to the reference layer. While Dy capped samples exhibit nonmagnetic 1/f noise, it is sufficiently small to be unimportant for read head operation at practical data rates.Comment: 13 pages (manuscript form), with 5 figures. Submitted for publicatio

    The Art of Doubting in <i>Obligationes Parisienses</i>

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    Recent studies on obligationes tend to focus on the specific type of positio. This emphasis has led to a neglect of the less standard types, including dubitatio. While some claim that dubitatio is merely a trivial variant of positio, we show that the dubitatio rules given in the 13th-century treatise Obligationes Parisienses are by no means trivial and in fact lend themselves to a somewhat peculiar system of dialogue. Dubitatio in this treatise shares many aspects with dubitatio in two other 13th-century treatises, by William of Sherwood and Nicholas of Paris. We use these similarities to shed some light on the history of dubitatio in general and the interpretation of the Parisienses rules in particular

    The Art of Doubting in <i>Obligationes Parisienses</i>

    Get PDF
    Recent studies on obligationes tend to focus on the specific type of positio. This emphasis has led to a neglect of the less standard types, including dubitatio. While some claim that dubitatio is merely a trivial variant of positio, we show that the dubitatio rules given in the 13th-century treatise Obligationes Parisienses are by no means trivial and in fact lend themselves to a somewhat peculiar system of dialogue. Dubitatio in this treatise shares many aspects with dubitatio in two other 13th-century treatises, by William of Sherwood and Nicholas of Paris. We use these similarities to shed some light on the history of dubitatio in general and the interpretation of the Parisienses rules in particular

    Reorientation Transition in Single-Domain (Ga,Mn)As

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    We demonstrate that the interplay of in-plane biaxial and uniaxial anisotropy fields in (Ga,Mn)As results in a magnetization reorientation transition and an anisotropic AC susceptibility which is fully consistent with a simple single domain model. The uniaxial and biaxial anisotropy constants vary respectively as the square and fourth power of the spontaneous magnetization across the whole temperature range up to T_C. The weakening of the anisotropy at the transition may be of technological importance for applications involving thermally-assisted magnetization switching.Comment: 4 pages, 4 figure

    Evaluation of European Land Data Assimilation System (ELDAS) products using in site observations

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    Three land-surface models with land-data assimilation scheme (DA) were evaluated for one growing season using in situ observations obtained across Europe. To avoid drifts in the land-surface state in the models, soil moisture corrections are derived from errors in screen-level atmospheric quantities. With the in situ data it is assessed whether these land-surface schemes produce adequate results regarding the annual range of the soil water content, the monthly mean soil moisture content in the root zone and evaporative fraction (the ratio of evapotranspiration to energy available at the surface). DA considerably reduced bias in net precipitation, while slightly reducing RMSE as well. Evaporative fraction was improved in dry conditions but was hardly affected in moist conditions. The amplitude of soil moisture variations tended to be underestimated. The impact of improved land-surface properties like Leaf Area Index, water holding capacity and rooting depth may be as large as corrections of the DA systems. Because soil moisture memorizes errors in the hydrological cycle of the models, DA will remain necessary in forecast mode. Model improvements should be balanced against improvements of DA per se. Model bias appearing from persistent analysis increments arising from DA systems should be addressed by model improvement

    De skeletten uit het grafmonument te Rijnsburg: een hernieuwd onderzoek

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    A renewed research of the remains of skeletons in the sepulchral monument at Rijnsburg, which were excavated in the years 1949/50 and were then ascribed to family members of the count of Holland, took place in the years 1995/96. A bone sample was taken from the left thighbone of each of the 16 skeletons for the purpose of 14C datings. The results show a 300 to 600 years' discrepancy with the supposed historical data. From the physiological-anthropological research it was concluded that the demographic and osteopathological findings are inconsistent with the historically known information to such a degree, that there is no ground for a positive identification with the members of the count's family of Holland buried at Rijnsburg. An extensive analysis of all the historical and archaeological information with respect to these skeletons, in combination with the above-mentioned research results, led to the conclusion that the researched skeletons belonged to a sepulchral field below the foundations of the church, which was there before the abbey church was built. This sepulchral field forms part of the settlement known from historical and archaeological information and for the greater part dates back to the 9th to 11th centuries, with a few graves dating from the Merovingian period (early 7th century)
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