Critical scale invariance in a healthy human heart rate

We demonstrate the robust scale-invariance in the probability density function (PDF) of detrended healthy human heart rate increments, which is preserved not only in a quiescent condition, but also in a dynamic state where the mean level of the heart rate is dramatically changing. This scale-independent and fractal structure is markedly different from the scale-dependent PDF evolution observed in a turbulentlike, cascade heart rate model. These results strongly support the view that a healthy human heart rate is controlled to converge continually to a critical state.     

When Langmuir is too simple: H2 dissociation on Pd(111) at high coverage

Recent experiments of H2 adsorption on Pd(111) [Nature (London) 422, 705 (2003)]] have questioned the classical Langmuir picture of second order adsorption kinetics at high surface coverage requiring pairs of empty sites for the dissociative chemisorption. Experiments find that at least three empty sites are needed. Through density functional theory, we find that H2 dissociation is favored on ensembles of sites that involve a Pd atom with no direct interaction with adsorbed hydrogen. Such active sites are formed by aggregation of at least 3 H-free sites revealing the complex structure of the "active sites."     

Dynamics of desorption induced by electronic transitions: Desorption of neutrals from physisorbed layers

The dynamical theory of desorption from physisorbed layers irradiated by electrons or photons is presented. The basic steps of the microscopic mechanism are: ionization to a more strongly bound state, acceleration towards the surface, reneutralization, and finally, desorption. Desorption yields and the kinetic energy distributions of desorbing neutrals obtained in the classical and in the fully quantum-mechanical approach are numerically compared. Comparison with the existing experimental data is also made. Next, the classical trajectory approximation is applied to study the metal — adsorbate charge transfer process. The neutralization rate obtained is compared with the one following from the conventional perturbation theory. Viene presentata la teoria dinamica di desorbimento da strati fisisorbiti irraggiati da elettroni o fotoni. Le fasi basilari del meccanismo microscopico sono: ionizzazione ad uno stato più fortemente legato, accelerazione verso la superficie, rineutralizzazione ed infine, desorbimento. Vengono confrontati numericamente i rendimenti di desorbimento e le distribuzioni di energia cinetica delle specie neutre desorbite, ottenute nello schema classico e in quello totalmente quanto-mccanico. Si confrontano inoltre i dati sperimentali esistenti.     

Universal scaling law in human behavioral organization

We describe the nature of human behavioral organization, specifically how resting and active periods are interwoven throughout daily life. Active period durations with physical activity count successively above a predefined threshold, when rescaled with individual means, follow a universal stretched exponential (gamma-type) cumulative distribution with characteristic time, both in healthy individuals and in patients with major depressive disorder. On the other hand, resting period durations below the threshold for both groups obey a scale-free power-law cumulative distribution over two decades, with significantly lower scaling exponents in the patients. We thus find universal distribution laws governing human behavioral organization, with a parameter altered in depression.     

pH and temperature-sensitive N-isopropylacrylamide ampholytic networks incorporating L-lysine

Ampholytic polymer gels based on N-isopropylacrylamide (NIPA) and natural amino acid L-lysine were prepared by free radical polymerization in aqueous solutions. To make amino acids attachable to the polymer chain, the acrylic group was added to the epsilon-amino group of lysine to obtain N-epsilon-acrylic-lysine (Z). Finally, a new temperature- and pH-sensitive (NIPA-Z) hydrogel was obtained. The presence of amino and carboxylic groups of amino acids gave us a possibility to control the amount and sign of the excessive charge on the polymeric network with respect to pH. The swelling behavior of the NIPA-Z hydrogels with respect to the amount of Z (0-4%), temperature, and pH was investigated. Temperature and pH were changed in the ranges of 20-50 degrees C and 2-12, respectively. To eliminate the influence of ionic strength on the swelling behavior, this parameter was kept constant in all experiments. It was found that the pH dependence of the degree of swelling for the NIPA-Z gels, measured at constant temperature, exhibits a minimum. Such a minimum was seen for the ampholyte networks with independent acidic and basic groups attached to the polymer chains. For the NIPA-Z gels, the minimum was wide, and the pH range over which it was spread corresponded well to the pH distribution of the zwitterions. The way the gel volume changed with an increase in temperature depends on the amino acid amount. It is initially discontinuous and turns to the continuous one for the higher percentage of amino acid. The temperature dependence of the swelling process obtained for different pH values clearly shows that for the pH region where the zwitterions dominate, the polymer networks collapse more efficiently.     

Spin Correlations in Nonrelativistic Quantum Mechanics

Einstein—Podolsky—Rosen spin correlations in the framework of nonrelativistic quantum mechanics for moving observers are calculated. The measurements are performed in bounded regions of space (detectors), not necessarily simultaneously. The resulting correlation function depends not only on the directions of spin measurements but also on the relative velocity of the observers.     

Spectroscopic Characterization of Eu(III) Complexes with New Monophosphorus Acid Derivatives of H<Subscript>4</Subscript>dota

The luminescence lifetimes of europium(III) complexes with new monophosphorus acid derivatives of H₄dota were measured by means of time-resolved laser-induced luminescence spectroscopy in H₂O and D₂O. The hydration numbers of these complexes were estimated using different empirical equations [Horrocks and Sudnick (1979) J. Am. Chem. Soc. 101 (1979) 334; Choppin and Barthelemy(1989) Inorg. Chem. 28, 3354–3357; Choppin and Bünzli Lanthanide probes in life, chemical and earth sciences. Theory and practice (1989); Kimura and Kato J. Alloys Comp. 275–277 (1998) 806; Parker (1999) J. Chem. Soc., Perkin Trans. 2, 493–503; Supkowski and Horroks (2002) Inorg. Chim. Acta. 340, 44–48]. It was shown that all the relationships gave similar results with a satisfactory precision. The hydration numbers of complexes of H₃do3a and H₄dota agreed with the literature values. One water molecule is coordinated in complexes of the new ligands. The results showed that the Choppin formula based on measurements only in H₂O can be satisfactorily used for estimation of the hydration numbers.     

The Valentiner group as Galois group

We obtain the complete set of solutions to the Galois embedding problem given by the Valentiner group as a triple cover of the alternating group .

     

Phase transition in a healthy human heart rate

A healthy human heart rate displays complex fluctuations which share characteristics of physical systems in a critical state. We demonstrate that the human heart rate in healthy individuals undergoes a dramatic breakdown of criticality characteristics, reminiscent of continuous second order phase transitions. By studying the germane determinants, we show that the hallmark of criticality--highly correlated fluctuations--is observed only during usual daily activity, and a breakdown of these characteristics occurs in prolonged, strenuous exercise and sleep. This finding is the first reported discovery of the dynamical phase transition phenomenon in a biological control system and will be a key to understanding the heart rate control system in health and disease.     

Equlibrium measure of a product subset of

In this note we show that an equilibrium measure of a product of two subsets of and , respectively, is a product of their equilibrium measures. We also obtain a formula for , where are locally bounded plurisubharmonic functions and .