628 research outputs found
An Evolutionary Analysis of World Energy Consumption and World Population
The evolution of large-scale systems is described by a model based on the assumption of hyperbolic growth and saturation processes. It is shown that this Hyper-Logistic Evolution Model (HLEM) successfully describes the development of world population and global primary energy consumption over the past century; the model is also used to provide projections of world population and primary energy consumption up to the year 2100
Dynamic Problems of Evolution
Evolution and growth of natural and man-made processes have impressed human beings from the very beginning. What is evolution? Is it the passage from an initial to a higher stage? What does "higher" mean in a world of many objectives? Is "higher" bound to the existence of monotonous indicators like entropy, or is it "gambling" within a predetermined combinatoric multifold of possibilities?
Questions of this kind arise from the phenomena in our environment, from the spring-off of new species, but also from processes in our man-made technological world. How is the transition of basic innovation to technology and use of the corresponding products by society, what forecast can be made from increasing CO2, in the atmosphere on the impact on climate, from features of seismologic waves on future events etc. That means there is a strong connection between evolution processes and the emphasis of systems analysis as a help for strategic actions.
This paper deals with general considerations about possible growth mechanisms as a base for creating valid growth models. But the main goal is to show how the parameters in growth models can be estimated using on one hand a fuzzy approach together with vector optimization and on the other hand a Bayesian approach. It can be seen that both approaches are useful and applicable and we get informations from one approach which the other one cannot give us. We studied already the growth of cracks in materials, processes well described in [10]. Preliminary results are contained in [13].
Research will be continued to identify the superposition of driving forces and of coupled systems in which oscillations can arise because of time delays between their driving-force pulses
Graphene formed on SiC under various environments: Comparison of Si-face and C-face
The morphology of graphene on SiC {0001} surfaces formed in various
environments including ultra-high vacuum, 1 atm of argon, and 10^-6 to 10^-4
Torr of disilane is studied by atomic force microscopy, low-energy electron
microscopy, and Raman spectroscopy. The graphene is formed by heating the
surface to 1100 - 1600 C, which causes preferential sublimation of the Si
atoms. The argon atmosphere or the background of disilane decreases the
sublimation rate so that a higher graphitization temperature is required, thus
improving the morphology of the films. For the (0001) surface, large areas of
monolayer-thick graphene are formed in this way, with the size of these areas
depending on the miscut of the sample. Results on the (000-1) surface are more
complex. This surface graphitizes at a lower temperature than for the (0001)
surface and consequently the growth is more three-dimensional. In an atmosphere
of argon the morphology becomes even worse, with the surface displaying
markedly inhomogeneous nucleation, an effect attributed to unintentional
oxidation of the surface during graphitization. Use of a disilane environment
for the (000-1) surface is found to produce improved morphology, with
relatively large areas of monolayer-thick graphene.Comment: 22 pages, 11 figures, Proceedings of STEG-2 Conference; eliminated
Figs. 4 and 7 from version 1, for brevity, and added Refs. 18, 29, 30, 31
together with associated discussio
Diacylglycerol kinase zeta inhibits G alpha q-induced atrial remodeling in transgenic mice
ArticleHEART RHYTHM. 6(1):78-84 (2009)journal articl
The additional value of CT images interpretation in the differential diagnosis of benign vs. malignant primary bone lesions with 18F-FDG-PET/CT
Objective: To evaluate the value of a dedicated interpretation of the CT images in the differential diagnosis of benign vs. malignant primary bone lesions with 18fluorodeoxyglucose-positron emission tomography/computed tomography (18F-FDG-PET/CT). Materials and methods: In 50 consecutive patients (21 women, 29 men, mean age 36.9, age range 11-72) with suspected primary bone neoplasm conventional radiographs and 18F-FDG-PET/CT were performed. Differentiation of benign and malignant lesions was separately performed on conventional radiographs, PET alone (PET), and PET/CT with specific evaluation of the CT part. Histology served as the standard of reference in 46 cases, clinical, and imaging follow-up in four cases. Results: According to the standard of reference, conventional 17 lesions were benign and 33 malignant. Sensitivity, specificity, and accuracy in assessment of malignancy was 85%, 65% and 78% for conventional radiographs, 85%, 35% and 68% for PET alone and 91%, 77% and 86% for combined PET/CT. Median SUVmax was 3.5 for benign lesions (range 1.6-8.0) and 5.7 (range 0.8-41.7) for malignant lesions. In eight patients with bone lesions with high FDG-uptake (SUVmax ≥ 2.5) dedicated CT interpretation led to the correct diagnosis of a benign lesion (three fibrous dysplasias, two osteomyelitis, one aneurysmatic bone cyst, one fibrous cortical defect, 1 phosphaturic mesenchymal tumor). In four patients with lesions with low FDG-uptake (SUVmax < 2.5) dedicated CT interpretation led to the correct diagnosis of a malignant lesion (three chondrosarcomas and one leiomyosarcoma). Combined PET/CT was significantly more accurate in the differentiation of benign and malignant lesions than PET alone (p = .039). There was no significant difference between PET/CT and conventional radiographs (p = .625). Conclusion: Dedicated interpretation of the CT part significantly improved the performance of FDG-PET/CT in differentiation of benign and malignant primary bone lesions compared to PET alone. PET/CT more commonly differentiated benign from malignant primary bone lesions compared with conventional radiographs, but this difference was not significan
Observations of a high‐latitude stable electron auroral emission at ∼16 MLT during a large substorm
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94792/1/jgra21045.pd
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Modeling the observed proton aurora and ionospheric convection responses to changes in the IMF clock angle: 1. Persistence of cusp proton aurora
We employ a numerical model of cusp ion precipitation and proton aurora emission to fit variations of the peak Doppler-shifted Lyman-a intensity observed on 26 November 2000 by the SI-12 channel of the FUV instrument on the IMAGE satellite. The major features of this event appeared in response to two brief swings of the interplanetary magnetic field (IMF) toward a southward orientation. We reproduce the observed spatial distributions of this emission on newly opened field lines by combining the proton emission model with a model of the response of ionospheric convection. The simulations are based on the observed variations of the solar wind proton temperature and concentration and the interplanetary magnetic field clock angle. They also allow for the efficiency, sampling rate, integration time and spatial resolution of the FUV instrument. The good match (correlation coefficient 0.91, significant at the 98% level) between observed and modeled variations confirms the time constant (about 4 min) for the rise and decay of the proton emissions predicted by the model for southward IMF conditions. The implications for the detection of pulsed magnetopause reconnection using proton aurora are discussed for a range of interplanetary conditions
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