Leading circle model

Allessie MA, Bonke FIM, Schopman FJG Circus movement in rabbit atrial muscle as a mechanism of tachycardia. III. The leading circle concept A new model of circus movement in cardiac tisue without the involvement of an anatomical obstacle. Cite Res 1977 41 9-18. 

Allessie, M. A., Bonke, F. I. M., Shopman, F. J. G. (1977) Circus movement in rabbit atrial muscle as a mechanism of tachycardia. III. The leading circle concept A new model of circus movement in cardiac tissue without the involvement of an anatomical obstacle. Circ. Res. 41, 9 Arneodo, A., Coullet, P., Tresser, C. (1981) A possible new mechanism for the onset of turbulence. Phys. Lett. 81A, 197... 

Fig. 4. A schematic two-dimensional illustration of the idea for an information theory model of hydrophobic hydration. Direct insertion of a solute of substantial size (the larger circle) will be impractical. For smaller solutes (the smaller circles) the situation is tractable a successful insertion is found, for example, in the upper panel on the right. For either the small or the large solute, statistical information can be collected that leads to reasonable but approximate models of the hydration free energy, Eq. (7). An important issue is that the solvent configurations (here, the point sets) are supplied by simulation or X-ray or neutron scattering experiments. Therefore, solvent structural assumptions can be avoided to some degree. The point set for the upper panel is obtained by pseudo-random-number generation so the correct inference would be of a Poisson distribution of points and = kTpv where v is the van der Waals volume of the solute. Quasi-random series were used for the bottom panel so those inferences should be different. See Pratt et al. (1999).

Yet it is on the issues of reproducibility and instrumentation that Occult Chemistry failed to persuade, at least outside of Theosophical circles and the small group of scientists in recent years who have been willing to work entirely at the level of theory. Besant and Leadbeater could move beyond older models of science, which based themselves upon deductions from revealed principles (alchemical or scientific deductions from the writings of the Hermetic tradition, for instance, or from the revelations of H. P. Blavatsky), by turning to experimentation. Not surprisingly, their form of experimentation did not admit of reproducibility. In spite of efforts by Stephen Phillips to conduct blind trials using a Buddhist clairvoyant to confirm Besant and Lead-beater s micro-psi visions (1996,48), direct experience is neither convincingly verifiable nor falsifiable. 

Fig. 3 Relative dipole-bound anion formation rates in RET collisions between Rydberg Xe(nf) atoms with (a) adenine (circles) or imidazole (squares) molecules and (b) adenine-imidazole complex produced in a supersonic beam. Experimental data are fitted to curvecrossing model calculations which lead to the experimental determination of EAdS values, equal to 11 meV for adenine, 23 meV for imidazole and 54 meV for adenine-imidazole complex (reproduced by permission of the American Chemical Society).

Figure 1. Schematic representation of remodelling mechanisms. (Adapted form Langst and Becker, 2004.) The schemes show nucleosomes from the top. (a) The twist diffusion model - Twisting of DNA moves it over the histone surface in one base pair increments. This changes the position of the DNA with respect to the histone, as shown by the open and closed circles, (b) The Loop recapture model - Extranucleosomal DNA is pulled into the nucleosomes to replace a DNA segment which consequently loops out. This loop is then propragated over the histone surface like ripples of a wave. The star,, indicates how this leads to a change in the position of DNA relative to the nucleosome. (See Colour Plate 4.)...

The experimental data (dots) are reproduced very well within the framework of the hydraulic permeation model (solid lines). For the basic case with zero gas pressure gradient between cathode and anode sides, APe = 0, the model (solid line) predicts uniform water distribution and constant membrane resistance at )p < 1 A cm and a steep increase in R/R beyond this point. These trends are in excellent agreement with experimental data (open circles) for Nafion 112 in Figure 6.15. A finife positive gas pressure gradient, APs = P/ - P/ > 0, improves the internal humidification of fhe membrane, leading to more uniform water distribution and significantly reduced dependence of membrane resistance on X. The latter trends are consistent with the predictions of fhe hydraulic permeation model. 

Fig. 4.3. (a) Locations x, 1 < i < 5,000, of compounds (circles) and rj, 1 < j < 12, of lead compounds (crosses) in the 2-d descriptor space determined from the original algorithm, (b) Relative weights Xj associated with different locations of lead compounds. Reprinted ( adapted or in part ) with permission from Journal of Chemical Information and Modeling. Copyright 2008 American Chemical Society. 

Figure 23.7 Vertical profiles of water temperature (dotted line) and of measured (circles) and calculated (solid line) PCE concentration in Greifensee (Switzerland) for the period May to October 1985. Numbers give PCE inventory in moles (M = measured, C = calculated). From the model calculation it can be concluded that between May 6 and July 1, 1985, about 360 moles of PCE entered the lake, thus leading to a significant increase of the concentration in the lake during several months. After July 1, the input was virtually zero.

The developed model was applied to the EPS experiment (Fig.lb) to extract information on the water dynamics. Similar to the previous report [17], the EPS function decreases rapidly at a time scale of -0.5 ps, then raises again at -2 ps, and finally falls off to zero. The EPS functions acquired while keeping the delays tn (empty circles) and t23 (solid circles) fixed [20], are shifted along the vertical axis which is a consequence of the relatively short excited-state lifetime (700 fs). The peak in the EPS function around -2 ps is explained in the framework of our model as arising from interference between the chromophore and solvent responses. The delicate balance between phases of genuinely nonlinear and thermal contributions as the delay t12 between the two excitation pulses is increased, leads to the enhancement of the integrated signal that is measured in the EPS experiment. 

Figure 1. Model of Polymeric Unit [Pbi(OH)/tY+. Lead atoms are designated by small circles. Large circles represent assumed positions for oxygen atoms (11)...

The other important case is a center-of-mass motion of molecules between the leads (Fig. 10). Here not the internal overlap integrals, but the coupling to the leads Vik<7,a(x) is fluctuating. This model is easily reduced to the general model (137), if we consider additionaly two not flexible states in the left and right leads (two atoms most close to a system), to which the central system is coupled (shown by the dotted circles). 

In the course of further measurements at Fr, Q = idem, the viscosity of the experimental liquid is reduced stepwise to raise Re towards Rej- compare the three hollow circles. The smaller the selected model-scale, the greater is the danger of this approach also finally leading to false extrapolation to Ne(ReT) We do not know that Re is no longer relevant at Re > 104 ... 

In the model derived by McClintock and Irwin the shape and size of the plastic zone were calculated by a combination of the stress field at the crack tip (e.g. Eq. (2)) with a yield criterion (e.g. von Mises, Tresca). This leads to the well known dog-bone type of plastic zone showing the influence of stress state. Its form is often approximated to by a circle of radius Tp, where... 

Fi< . 33. Shift data for two adsorbates on Pt/Rh catalysts as a function of overall Rh concentration. Squares and right-hand scale. H circles and left-hand scale. CO. In both cases application of a simple two-site rapid-exchange model (as in Fig. 32) would lead to the conclusion that the surface is enriched in Rh. At least for the CO-covered samples, additional NMR experiments do not confirm this conclusion 9S, 105). 

Fig. 6. (a) Interstitial pressure gradients in the mammary adenocarcinoma R3230AC as a function of radial position. The circles ( ) represent data points (Boucher et al., 1990), and the solid line represents the theoretical profile based on our previously developed mathematical model (Jain and Baxter, 1988 Baxter and Jain, 1989). Note that the pressure is nearly uniform in most of the tumor, but drops precipitously to normal tissue values in the periphery. Elevated pressure in the central region retards the extravasation of fluid and macromolecules. In addition, the pressure drop from the center to the periphery leads to an experimentally verifiable, radially outward fluid flow. (Reproduced from Boucher et al., 1990, with permission.) (b) Microvascular pressure (MVP) in the peripheral vessels of the mammary adenocarcinoma R3230AC is comparable to the central interstitial fluid pressure (IFP) (adapted from Boucher and Jain, 1992). These results suggest that osmotic pressure difference across vessel walls is small in this tumor. 

Oil biomarker compositions were measured in samples from three wells in the central part of the Ross Field (Fig. 11). Wells 13/28-2 and 13/28a-5 had similar compositions, but the oil in 13/29a-3 has a different composition, related to a higher thermal maturity. If diffusion was the only mechanism leading to fluid mixing, then in 40 Ma the oil would be able to mix over a distance of about 520 m, illustrated by dashed circles around the wells in Figure 11. It is thus possible that the biomarker differences were inherited from the reservoir filling history, and subsequently have not had time to mix completely. This would indicate that the oil chemistry could not be interpreted to indicate compartmentalization. However, it is possible that the biomarker maturity parameters reflect oils of different density (unfortunately, density was not measured in oils from the crucial location). Indeed, there are density differences between the oils in wells 13/29a-l and 13.29a-3. The density-mixing model (equation (10)) would indicate that density overturn would mix oil densities over the whole central part of the field... 

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