24,397 research outputs found
Developing a web-based cellular automata model for urban growth simulation
Cellular automata as an emerging technology have been adapted increasingly by geographers and planners to simulate the spatial and temporal processes of urban growth. While the literature reports many applications of cellular automata models for urban studies, in practice, the operation of the models as well as the configuration and calibration of relevant parameters used in the models were only known to the model builders. This is largely due to the constraint that most cellular automata models were developed based on desktop computer programs, either by incorporating the model within a desktop GIS environment, or developing the model independent of a desktop GIS. Consequently, there is little input from the user to test or visualise the actual operation or evaluate the applicability of the model under different conditions. This paper presents a methodology to implement a fuzzy constrained cellular automata model of urban growth within a web-based GIS environment, using the actual urban growth of Metropolitan Sydney, Australia from 1976 to 2006 as a case study. With the web-based cellular automata model, users can visualise and test the operation of the model; they can also modify or calibrate the model's parameters to evaluate its simulation accuracies, or even feed the model with various 'what-if' conditions to generate alterative outcomes. Such a web-based modelling platform provides a useful and effective channel for government authority and stakeholders to evaluate different urban growth scenarios. It also provides an interactive environment that can foster public participation in urban planning and management
"Sudden Drop" in Blood Pressure is Associated With Recanalization After Thrombolysis.
We aim to investigate whether the phenomenon of "sudden drop" in blood pressure (BP) within the first 2 hours is associated with vessel recanalization.We retrospectively examined clinical and imaging data from a consecutive series of patients with stroke with large vessel occlusion treated with intravenous thrombolysis (IVT). BP was monitored every 15 minutes during the first 2 hours, then every 30 minutes for 6 hours, and then every hour for 16 hours.We observed the phenomenon of "sudden drop" in systolic BP (≥20 mm Hg) in 82 (50.9%) patients in the first 2 hours and vessel recanalization in 87 (54.0%) patients 24 hours after treatment. This phenomenon was independently associated with recanalization (odds ratio 2.100; 95% confidence interval: 1.085-4.062; P = 0.028) after adjusting for the history of atrial fibrillation, coronary heart disease, and hypertension.The phenomenon of "sudden drop" in systolic BP with 20 mm Hg or greater between 2 continuous measurements within the first 2 hours is associated with recanalization after IVT in patients with large vessel occlusion, especially for middle cerebral artery occlusion
Leptonic decays in the littlest model with T-parity
The littlest model with T-parity (called the model) predicts
the existence of the T-odd leptons, which can generate contributions to some
leptonic processes at the one-loop level. We calculate their contributions to
the leptonic decay processes , , and
Z\rightarro \nu\bar{\nu}. We find that the T-odd leptons can give significant
contributions to the branching ratios of these decay processes in most of the
parameter space. The experimental measurement values might generate constraints
on the free parameters of the model.Comment: 16 pages, 8 figures, minor corrections; final version published in
Phys.Rev.
Number-resolved master equation approach to quantum transport under the self-consistent Born approximation
We construct a particle-number(n)-resolved master equation (ME) approach
under the self-consistent Born approximation (SCBA) for quantum transport
through mesoscopic systems. The formulation is essentially non-Markovian and
incorporates the interlay of the multi-tunneling processes and many-body
correlations. The proposed n-SCBA-ME goes completely beyond the scope of the
Born-Markov master equation, being applicable to transport under small bias
voltage, in non-Markovian regime and with strong Coulomb correlations. For
steady state, it can recover not only the exact result of noninteracting
transport under arbitrary voltages, but also the challenging nonequilibrium
Kondo effect. Moreover, the n-SCBA-ME approach is efficient for the study of
shot noise.We demonstrate the application by a couple of representative
examples, including particularly the nonequilibrium Kondo system.Comment: arXiv admin note: substantial text overlap with arXiv:1302.638
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