We consider real valued functions $f$ defined on a subinterval $I$ of the positive real axis and prove that if all of $f$’s quantum differences are nonnegative then $f$ has a power series representation on $I$. Further, if the quantum differences have fixed sign on $I$ then $f$ is analytic on $I$.
We define Bernstein-type operators on the half line $\mathopen [0,+\infty \mathclose [$ by means of two sequences of strictly positive real numbers. After studying their approximation properties, we also establish a Voronovskaja-type result with respect to a suitable weighted norm.
The study investigated whether specific changes in phase synchrony in the beta 2 frequency band of EEG (25-35 Hz) occurred during a recognition task. The level of synchrony was examined between one hundred and eighty loci in the frontal and temporal lobes of eight epileptic patients with intracerebral electrodes; the EEG records were obtained during a visual oddball task. In each pair of records, the correlation curves were created from the sequence of correlation coefficients calculated. These curves consisted of irregular oscillations between the maximal and minimal r-values. Transient highly synchronized activity was observed during the whole time course of the experiment in all record pairs investigated and a significant relationship was found between the number of such episodes and the mean correlation coefficient (Spearman R 0.84; N 3240; p<0.001). On averaged curves, which were calculated using stimulus onsets as the trigger of averaging, a significant increase of the mean correlation coefficient in the post-stimulus epoch was found (p<0.01 after both target and non-target stimuli; t-test for dependent samples). As the cognitive demand significantly increases after stimulus presentation, the results are considered to be the first evidence from intracranial recording of increased synchronization in the beta 2 frequency band related to the cognitive activity., M. Kukleta ... [et al.]., and Obsahuje seznam literatury
The utility of biodiversity measures that incorporate pairwise species functional differences is becoming increasingly recognized. Functional diversity is regarded as the key for linking community composition to ecosystem processes like productivity, nutrient cycling, carbon sequestration, or stability when subject to perturbations. Therefore, several indices have been proposed to measure the functional diversity of a given species assemblage. The principle behind these measures is that a species assemblage with high functional overlap among species has a lower functional diversity than an assemblage with low functional overlap. On the other hand, the variability in the species functional characters among different species assemblages (i.e., functional beta diversity) has received much less attention. The aim of this paper is thus to discuss a general framework for calculating functional beta diversity from plot-to-plot functional dissimilarity matrices. To illustrate our proposal we use data from two beech forest stands with different management histories in central Italy. The results of our analysis show that, though the two stands are significantly different from one another in terms of their species functional traits, the difference in their functional beta diversity values is only marginally significant. These results are related to the characteristic scale at which ecological variations occur in the two stands.
β-adrenergic receptors (β-ARs) play a pivotal role in the cardiovascular regulation. In the human heart β1- and β2-ARs dominate in atria as well as in ventricle influencing heart rate and myocardial contractility. Some single nucleotide polymorphisms (SNPs) of β-ARs might influence cardiovascular function. However, the influence of β-AR genes SNPs on hemodynamic parameters at rest and their reactivity under stress is still not well known. We aimed to explore the associations between four selected β-ARs gene polymorphisms and selected cardiovascular measures in eighty-seven young healthy subjects. While in β1-AR polymorphism rs1801252 no significant association was observed, second β1-AR polymorphism rs1801253 was associated with decreased cardiac output and cardiac index during all phases and with decreased flow time corrected and ejection time index at rest and during mental arithmetics. Polymorphism rs1042713 in β2-AR was associated with alterations in blood pressure variability at rest and during head-up-tilt, while rs1042714 was associated predominantly with decreased parameters of cardiac contractility at rest and during mental arithmetics. We conclude that complex analysis of various cardiovascular characteristics related to the strength of cardiac contraction and blood pressure variability can reveal subtle differences in cardiovascular sympathetic nervous control associated with β-ARs polymorphisms.
Beta-integers were defined as a generalization of integers by Alfréd Rényi in 1957 in the course of his study of expansions of real numbers in non-integer bases. Together with mathematicians, crystallographers are also interested in this unusual structure. They have found out that beta-lattices are in particular convenience for the description of quasicrystals and their diffraction images., Ľubomíra Balková., and Obsahuje bibliografii