1,557 research outputs found
Use of a mobile platform for assessing urban heat stress in Rotterdam
In this study, an assessment of the intensity of the urban heat island (UHI) in Rotterdam was carried out using an innovative mobile bio-meteorological measuring platform mounted on a cargo bicycle. The goal was to assess whether or not heat stress is currently or likely to become a critical issue. Physiological equivalent temperatures were calculated directly from the measurements. Preliminary results show how effective urban parks and greenery are in reducing the UHI. The maximum UHI was about 7 K warmer than the rural area, whereas greener urban configurations were under 3 K warmer. City parks show marked cooling effects during daytime. The preliminary results clearly demonstrate the presence of a considerable UHI in Rotterdam, which is expected to be found in other Dutch cities, and confirms the important role of green spaces in mitigating urban heat stress
Gemeten actuele verdamping voor twaalf locaties in Nederland
Stowa heeft Alterra de opdracht gegeven jaarreeksen van actuele dagelijkse verdamping af te leiden voor twaalf meetlocaties in Nederland. Daarbij is gebruik gemaakt van bestaande (micro)meteorologische meetgegevens. De meetgegevens zijn gecontroleerd op kwaliteit en continuĂŻteit en ontbrekende dagtotalen zijn aangevuld met door een Artificieel Neuraal Netwerk gesimuleerde gegevens. De onzekerheid in de jaartotalen van de bepaalde actuele verdamping ligt tussen de 10 en 15%
Interobserver Variation of Colour Duplex Scanning of the Popliteal,Tibial and Pedal Arteries
AbstractObjectives: to determine interobserver variation in the measurement of Peak Systolic Velocity (PSV) and grading of disease by means of Duplex scanning (DS) in the popliteal, tibial and pedal arteries. Design: prospective validation study. Materials twenty-four consecutive patients with severe claudication (n=6), ischaemic rest pain (n=11) and tissue loss (n=7). Methods two vascular technologists independently examined the popliteal, tibial and pedal arteries. The PSV was recorded in 15 arterial segments that were graded with B-mode and Doppler parameters as fully patent, severely diseased or occluded. Concordance in PSV recordings was expressed as intraclass correlation coefficients (ICC). Agreement in artery assessment was expressed as weighted Îş-values. Results the ICC for PSV measurements was 0.90 (95% CI, 0.86 to 0.93) within the popliteal and tibial arteries and 0.64 (95% CI, 0.37 to 0.81) within the pedal arteries. Agreement for grading disease was good within the popliteal and tibial arteries (Îş 0.66, 95% CI, 0.58 to 0.74), and moderate within the pedal arteries (Îş 0.54, 95% CI 0.33 to 0.74). The presence of diabetes or stage of disease did not influence interobserver agreement. Conclusion interobserver agreement of DS is good within the popliteal and tibial arteries and moderate within the pedal arteries
Dielectronic Recombination in Li+ Ions
This research was sponsored by the National Science Foundation Grant NSF PHY-931478
Dielectronic Recombination in Li+ Ions
This research was sponsored by the National Science Foundation Grant NSF PHY-931478
The Gross-Neveu Model from String Theory
We study an intersecting D-brane model which at low energies describes
(1+1)-dimensional chiral fermions localized at defects on a stack of N_c
D4-branes. Fermions at different defects interact via exchange of massless
(4+1)-dimensional fields. At weak coupling this interaction gives rise to the
Gross-Neveu (GN) model and can be studied using field theoretic techniques. At
strong coupling one can describe the system in terms of probe branes
propagating in a curved background in string theory. The chiral symmetry is
dynamically broken at zero temperature and is restored above a critical
temperature T_c which depends on the coupling. The phase transition at T_c is
first order at strong coupling and second order at weak coupling.Comment: 32 pages, harvmac (b
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