A numerical fit of analytical to simulated density profiles in dark matter haloes

Analytical and geometrical properties of generalized power-law (GPL) density profiles are investigated in detail. In particular, a one-to-one correspondence is found between mathematical parameters and geometrical parameters. Then GPL density profiles are compared with simulated dark haloes (SDH) density profiles, and nonlinear least-absolute values and least-squares fits involving the above mentioned five parameters (RFSM5 method) are prescribed. More specifically, the sum of absolute values or squares of absolute logarithmic residuals is evaluated on a large number of points making a 5-dimension hypergrid, through a few iterations. The size is progressively reduced around a fiducial minimum, and superpositions on nodes of earlier hypergrids are avoided. An application is made to a sample of 17 SDHs on the scale of cluster of galaxies, within a flat $\Lambda$CDM cosmological model (Rasia et al. 2004). In dealing with the mean SDH density profile, a virial radius, averaged over the whole sample, is assigned, which allows the calculation of the remaining parameters. Using a RFSM5 method provides a better fit with respect to other methods. No evident correlation is found between SDH dynamical state (relaxed or merging) and asymptotic inner slope of the logarithmic density profile or (for SDH comparable virial masses) scaled radius. Mean values and standard deviations of some parameters are calculated, and a comparison with previous results is made with regard to the scaled radius. A certain degree of degeneracy is found in fitting GPL to SDH density profiles. If it is intrinsic to the RFSM5 method or it could be reduced by the next generation of high-resolution simulations, still remains an open question.Comment: 44 pages, 6 figures, updated version with recent results from high-resolution simulations (Diemand et al. 2004; Reed et al. 2005) included in the discussion; accepted for publication on SAJ (Serbian Astronomical Journal

Bioelectrical signal processing in cardiac and neurological applications and electromyography: physiology, engineering, and noninvasive applications

The present article reviews two recent books dealing with rather closely related subjects; in fact, they tend to complement and supplement reciprocally. Obviously, the electromyogram is a bioelectrical signal that often is mathematically manipulated in different ways to better extract its information. Moreover, its correlation with other bioelectric variables may become necessary

50 years a biomedical engineer remembering a long and fascinating journey

Looking back at one point of life appears as a nice exercise to round out and summarize. However, the objective should not be simply to tell a story; it must transmit a message to the young. To start with, two concepts are useful: Respect for others begins when you learn to laugh at yourself and, taken from an old saying, I did not want to be poor ... but money wouldn't make me rich. After elementary and high schools, during times of turmoil, I describe my engineering school years at the University of Buenos Aires and a working experience in an international telecommunications company. Significant events taught me a concept, rooted in another motto: Isn't this house nice? It is my house, and I love it very much. In 1960, I began my activities in the USA. A couple of bad decisions resulted in significant events for me teaching me an important truth: "Beware of golden promises; time is the most precious asset". Finally, in 1972, settled down in Tucumán until retirement in 2001, a long period of productive activity came about, not without difficulties and also stained by a dark political interval. Crises seem to characterize our generations in Argentina. Non-the-less, there were some real accomplishments: an undergraduate program in BME and a National BME Society (SABI) plus an archive of specialized published material. After spending time following retirement in Peru and Italy, my current activity came as unexpected dessert at the University of Buenos Aires, with a small research group, so offering the opportunity of transmitting what I still have available

Honoring Leslie A. Geddes - Farewell ...

Honor thy father and thy mother, say the Holy Scriptures[1], for they at least gave thee this biological life, but honor thy teachers, too, for they gave thee knowledge and example

Neuroendocrinology and its Quantitative Development: A Bioengineering View

Biomedical engineering is clearly present in modern neuroendocrinology, and indeed has come to embrace it in many respects. First, we briefly review the origins of endocrinology until neuroendocrinology, after a long saga, was established in the 1950's decade with quantified results made possible by the radioimmunoassay technique (RIA), a development contributed by the physical sciences. However, instrumentation was only one face of the quantification process, for mathematical models aiding in the study of negative feedback loops, first rather shyly and now at a growing rate, became means building the edifice of mathematical neuroendocrinology while computer assisted techniques help unravel the associated genetic aspects or the nature itself of endocrine bursts by numerical deconvolution analysis. To end the note, attention is called to the pleiotropic characteristics of neuroendocrinology, which keeps branching off almost endlessly as bioengineering does too