1,357 research outputs found

    Bewegen in de toekomst: een trend verkenning

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    Een achtergrondstudie van maatschappelijke, ruimtelijke en technologische trends ten behoeve van de planvorming rond de as Haarlemmermeer-Almer

    Institutional interventions in complex urban systems: Coping with boundary issues in urban planning projects

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    __Abstract__ Urban planning projects are planned and organized through arrangements between actors. These arrangements are institutional interventions: they intervene in the institutional landscape as existing organizational boundaries are (temporarily) redrawn. Such boundary decisions are intended to simplify complexity. However, these boundary decisions also produce new complexities as new boundary issu

    Afbakeningsperikelen in ruimtelijke projecten

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    Projectmanagers proberen bewust ruimtelijke projecten af te bakenen om met de complexiteit van de stedelijke omgeving om te kunnen gaan. Daarmee wordt beoogd de externe afhankelijkheden te minimaliseren en zo de complexiteit beheersbaar te maken. Desondanks blijven externe afhankelijkheden bestaan. Voorwaarde om hiermee om te gaan is tijdige reflectie en het toepassen van een coping strategie, in plaats van vasthouden aan achterhaalde grenzen

    Physical health and the onset and persistence of depression in older adults: an eight-wave prospective community based study.

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    Background. Poor physical health has long been recognized to be one of the most important risk factors for depression in older adults. Since many aspects of physical health can be targeted for improvement in primary care, it is important to know whether physical health problems predict the onset and/or the persistence of depression. Methods. The study is based on a sample which at the outset consisted of 327 depressed and 325 non-depressed older adults (55-85) drawn from a larger random community-based sample in the Netherlands. Depression was measured using the Center for Epidemiologic Studies Depression scale (CES-D) at eight successive waves. Results. From all incident episodes, the majority (57%) was short-lived. These short episodes could generally not be predicted by physical health problems. The remaining incident episodes (43%) were not short-lived and could be predicted by poor physical health. Chronicity (34%) was also predicted by physical health problems. Conclusions. The study design with its frequent measurements recognized more incident cases than previous studies; these cases however did have a better prognosis than is often assumed. The prognosis of prevalent cases was rather poor. Physical health problems were demonstrated to be a predictor of both the onset and the persistence of depression. This may well have implications for prevention and intervention

    Prognostic factors for important clinical outcomes in patients with a severe infection

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    Patients who are admitted with a suspicion of a severe infection usually enter the hospital through the emergency department (ED). The recognition of prognostic factors in an early stage affects further treatment and might improve clinical outcomes. WE EXAMINED POSSIBLE PROGNOSTIC FACTORS FOR FOUR IMPORTANT OUTCOMES: intensive care unit (ICU) admission, positive blood cultures, mortality and re-admission. All adult patients arriving at the ED with a suspected infection for whom admittance and intravenous (iv) antibiotics were indicated were included between March and December 2006. Possible prognostic variables were obtained from medical history, physical examination and laboratory results during the ED presentation. Data were analysed using logistic regression analysis. A total of 295 ED patients were evaluated, of whom 27 were referred to the ICU, 62 had a positive blood culture, 16 died and 48 were re-admitted. In multivariate analysis, patients with a respiration rate of >25/min were at higher risk for ICU admission. Patients with a positive blood culture had a higher heart rate and a higher percentage of segmented neutrophils. Patients who died during admission were more likely to be older, confused and had lower blood pressure. Patients who were re-admitted within 30 days were more likely to be male, younger and less likely to have a positive blood culture. Routine clinical and biochemical information can be used to predict ICU admission, the presence of bacteraemia, mortality and re-admission (within 30 days) and should be taken into consideration for treatment decision

    Asymptotic tunneling conductance in Luttinger liquids

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    Conductance through weak constrictions in Luttinger liquids is shown to vanish with frequency ω\omega as c1ω2+c2ω2/g2c_1 \omega^2 + c_2 \omega^{2/g - 2}, where gg is a dimensionless parameter characterizing the Luttinger liquid phase, and c1c_1 and c2c_2 are nonuniversal constants. The first term arises from the ^^ Coulomb blockade' effect and dominates for g<1/2g < 1/2, whereas the second results from eliminating high-energy modes and dominates for g>1/2g > 1/2.Comment: Latex file + one appended postcript figur

    Resonant Photon-Assisted Tunneling Through a Double Quantum Dot: An Electron Pump From Spatial Rabi Oscillations

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    The time average of the fully nonlinear current through a double quantum dot, subject to an arbitrary combination of ac and dc voltages, is calculated exactly using the Keldysh nonequilibrium Green function technique. When driven on resonance, the system functions as an efficient electron pump due to Rabi oscillation between the dots. The pumping current is maximum when the coupling to the leads equals the Rabi frequency.Comment: 6 pages, REVTEX 3.0, 3 postscript figure

    Transport spectroscopy in a time-modulated open quantum dot

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    We have investigated the time-modulated coherent quantum transport phenomena in a ballistic open quantum dot. The conductance GG and the electron dwell time in the dots are calculated by a time-dependent mode-matching method. Under high-frequency modulation, the traversing electrons are found to exhibit three types of resonant scatterings. They are intersideband scatterings: into quasibound states in the dots, into true bound states in the dots, and into quasibound states just beneath the subband threshold in the leads. Dip structures or fano structures in GG are their signatures. Our results show structures due to 2ω\hbar\omega intersideband processes. At the above scattering resonances, we have estimated, according to our dwell time calculation, the number of round-trip scatterings that the traversing electrons undertake between the two dot openings.Comment: 8 pages, 5 figure

    Functionalised metal-organic frameworks: a novel approach to stabilising single metal atoms

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    We have investigated the potential of metal-organic frameworks for immobilising single atoms of transition metals using a model system of Pd supported on NH2-MIL-101(Cr). Our Transmission Electron Microscopy and in-situ Raman spectroscopy results give evidence for the first time that functionalised metal-organic frameworks may support, isolate and stabilise single atoms of palladium. Using Thermal Desorption Spectroscopy we were able to evaluate the proportion of single Pd atoms. Furthermore, in a combined theoretical-experimental approach, we show that the H-H bonds in a H2 molecule elongate by over 15% through the formation of a complex with single atoms of Pd. Such deformation would affect any hydrogenation reaction and thus the single atoms supported on metal-organic frameworks may become promising single atom catalysts in the future
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