Multifractal analysis of nonhyperbolic coupled map lattices: Application to genomic sequences

Symbolic sequences generated by coupled map lattices (CMLs) can be used to model the chaotic-like structure of genomic sequences. In this study it is shown that diffusively coupled Chebyshev maps of order 4 (corresponding to a shift of 4 symbols) very closely reproduce the multifractal spectrum $D_q$ of human genomic sequences for coupling constant $\alpha =0.35\pm 0.01$ if $q>0$. The presence of rare configurations causes deviations for $q<0$, which disappear if the rare event statistics of the CML is modified. Such rare configurations are known to play specific functional roles in genomic sequences serving as promoters or regulatory elements.Comment: 7 pages, 6 picture

Small plasma probe Patent

Small plasma probe using tungsten wire collector in tubular shiel

What Does Climate Change Mean for the Arctic? How is Alaska Being Affected?

The Environmental and Energy Study Institute (EESI) held a Congressional briefing on March 15, 2005 on the Arctic Climate Impact Assessment (ACIA) 1 and climate change impacts already observed in Alaska. The assessment, released in November 2004, is an intergovernmental report based on a four-year scientific study of the Arctic conducted by an international team of 300 scientists and sponsored by the eight arctic nations (Canada, Denmark, Finland, Iceland, Norway, Russia, Sweden and the United States) and six indigenous people's organizations. It concludes that the average winter temperatures in Alaska and other arctic regions have increased by 4 to 7 degrees Fahrenheit (3-4 degrees Celsius) in the past 50 years, twice the rate of the rest of the globe, and are projected to continue rising for the next century. Alaska is being affected by climate change and experienced its warmest summer on record in 2004, characterized by its worst fire season, unprecedented insect outbreaks, and significant coastal erosion. The warming has caused a decline in summer sea ice extent and thickness, allowing seasonal storms to increasingly erode portions of the Alaskan coastline. The Government Accountability Office (GAO) estimates costs of $100-400 million to move a single endangered Alaskan village, with some 184 villages seen as susceptible to flooding and erosion

Climate Change Post-2100: What are the Implications of Continued Greenhouse Gas Buildup?

The Environmental and Energy Study Institute (EESI) held a Congressional briefing on September 21, 2004 on the climate change implications of exceeding a doubling of carbon dioxide in the atmosphere from preindustrial levels (prior to the start of the Industrial Revolution). The concentration of carbon dioxide (CO2) in the lower atmosphere, the main heat-trapping greenhouse gas responsible for global warming, is now at its highest level in at least 400,000 years, and likely in the last 35 million years. This concentration stands 32 percent above CO2 levels preceding the Industrial Revolution. Much of the climate modeling reported in the media focuses on the impacts of a doubling of preindustrial CO2 before the end of this century. However, given current rates of anthropogenic (man-made) CO2 emissions and without policy and technology implementation to significantly reduce these rates, atmospheric CO2 concentrations are unlikely to stabilize at twice pre-industrial levels by 2100. They may eventually reach three to four times pre-industrial levels before stabilization is achieved. Several prominent climate research centers around the world are modeling such scenarios. EESI's briefing featured three leading climate change experts who discussed modeling of these CO2-emission scenarios, their potential impacts, and what would be required to avoid emissions trajectories that lead to a tripling or quadrupling of greenhouse gas concentrations

Dynamically dominant magnetic fields in the diffuse interstellar medium

Observations show that magnetic fields in the interstellar medium (ISM) often do not respond to increases in gas density as would be naively expected for a frozen-in field. This may suggest that the magnetic field in the diffuse gas becomes detached from dense clouds as they form. We have investigated this possibility using theoretical estimates, a simple magneto-hydrodynamic model of a flow without mass conservation and numerical simulations of a thermally unstable flow. Our results show that significant magnetic flux can be shed from dense clouds as they form in the diffuse ISM, leaving behind a magnetically dominated diffuse gas.Comment: 2 pages, 1 figure. In proceedings of IAU Symposium 259: "Cosmic magnetic fields: from planets to stars and galaxies", eds. K.G. Strassmeier, A.G. Kosovichev & J.E. Beckman in pres

Development of the orifice plate with a cone swirler flow conditioner

Purpose - The sensitivity of orifice plate metering to poorly conditioned and swirling flows are subjects of concerns to flow meter users and manufacturers. The distortions caused by pipe fittings and pipe installations upstream of the orifice plate are major sources of this type of non-standard flows. These distortions will alter the accuracy of metering up to an unacceptable degree. Design/methodology/approach - The design of orifice plate meters that are independent of the initial flow conditions of the upstream is a major object of flow metering. Either using a long straight pipe or a flow conditioner upstream of an orifice plate usually achieves this goal. The effect of cone swirler flow conditioner for both standard and non-standard flow conditions has been carried out in the experimental rig. The measuring of mass flow rate under different conditions and different Reynolds numbers were used to establish a change in discharge coefficient relative to a standard one. Findings - The experimental results using the cone swirler flow conditioner showed that the combination of an orifice plate and cone swirler flow conditioner is broadly insensitive to upstream disturbances. The results clearly show that this flow conditioner can attenuate the effect of both swirling and asymmetric flows on metering to an acceptable level. Originality/value - Previous work on the orifice plate has shown that the concept has promise. The results of using a combination of a cone swirler and orifice plate for non-standard flow conditions including swirling flow and asymmetric flow show this package can preserve the accuracy of metering up to the level required in the standards, providing that a new discharge coefficient is used for the combined swirler and orifice plate

Analytical reliability calculation of linear dynamical systems in higher dimensions

The recent application of reliability analysis to controller synthesis has created the need for a computationally efficient method for the estimation of the first excursion probabilities for linear dynamical systems in higher dimensions. Simulation methods cannot provide an adequate solution to this specific application, which involves numerical optimization of the system reliability with respect to the controller parameters, because the total computational time needed is still prohibitive. Instead, an analytical approach is presented in this paper. The problem reduces to the calculation of the conditional upcrossing rate at each surface of the failure boundary. The correlation between upcrossings of the failure surface for the different failure events may be addressed by the introduction of a multi-dimensional integral. An efficient algorithm is adopted for the numerical calculation of this integral. Also, the problem of approximation of the conditional upcrossing rate is discussed. For the latter there is no known theoretical solution. Three of the semi-empirical corrections that have been proposed previously for scalar processes are compared and it is shown that the correction should be based on the bandwidth characteristics of the system. Finally, examples that verify the validity of the analytical approximations for systems in higher dimensions are discussed

The magnetic field of M31 from multi-wavelength radio polarization observations

The configuration of the regular magnetic field in M31 is deduced from radio polarization observations at the wavelengths 6, 11 and 20 cm. By fitting the observed azimuthal distribution of polarization angles, we find that the regular magnetic field, averaged over scales 1--3 kpc, is almost perfectly axisymmetric in the radial range 8 to 14 kpc, and follows a spiral pattern with pitch angles of p\simeq -19\degr to p\simeq -8\degr. In the ring between 6 and 8 kpc a perturbation of the dominant axisymmetric mode may be present, having the azimuthal wave number m=2. A systematic analysis of the observed depolarization allows us to identify the main mechanism for wavelength dependent depolarization -- Faraday rotation measure gradients arising in a magneto-ionic screen above the synchrotron disk. Modelling of the depolarization leads to constraints on the relative scale heights of the thermal and synchrotron emitting layers in M31; the thermal layer is found to be up to three times thicker than the synchrotron disk. The regular magnetic field must be coherent over a vertical scale at least similar to the scale height of the thermal layer, estimated to be h\therm\simeq 1 kpc. Faraday effects offer a powerful method to detect thick magneto-ionic disks or halos around spiral galaxies.Comment: 17 pages, 16 figures, accepted for publication in A&

How wide are European borders? : On the integration effects of monetary unions

We use consumer price data for 81 European cities (in Germany, Austria, Finland, Italy, Spain, Portugal and Switzerland) to study the impact of the introduction of the euro on goods market integration. Employing both aggregated and disaggregated consumer price index (CPI) data we confirm previous results which showed that the distance between European cities explains a significant amount of the variation in the prices of similar goods in different locations. We also find that the variation of relative prices is much higher for two cities located in different countries than for two equidistant cities in the same country. Under the EMU, the elimination of nominal exchange rate volatility has largely reduced these border effects, but distance and border still matter for intra-European relative price volatility