Search results for "Oscillometry"
showing 10 items of 30 documents
Levy targeting and the principle of detailed balance
2011
We investigate confining mechanisms for Lévy flights under premises of the principle of detailed balance. In this case, the master equation of the jump-type process admits a transformation to the Lévy-Schrödinger semigroup dynamics akin to a mapping of the Fokker-Planck equation into the generalized diffusion equation. This sets a correspondence between above two stochastic dynamical systems, within which we address a (stochastic) targeting problem for an arbitrary stability index μ ε (0,2) of symmetric Lévy drivers. Namely, given a probability density function, specify the semigroup potential, and thence the jump-type dynamics for which this PDF is actually a long-time asymptotic (target) …
Analytical properties of horizontal visibility graphs in the Feigenbaum scenario
2012
Time series are proficiently converted into graphs via the horizontal visibility (HV) algorithm, which prompts interest in its capability for capturing the nature of different classes of series in a network context. We have recently shown [1] that dynamical systems can be studied from a novel perspective via the use of this method. Specifically, the period-doubling and band-splitting attractor cascades that characterize unimodal maps transform into families of graphs that turn out to be independent of map nonlinearity or other particulars. Here we provide an in depth description of the HV treatment of the Feigenbaum scenario, together with analytical derivations that relate to the degree di…
Omnibus experiment: CPT and CP violation with sterile neutrinos
2017
The verification of the sterile neutrino hypothesis and, if confirmed, the determination of the relevant oscillation parameters is one of the goals of the neutrino physics in near future. We propose to search for the sterile neutrinos with a high statistics measurement utilizing the radioactive sources and oscillometric approach with large liquid scintillator detector like LENA, JUNO, or RENO-50. Our calculations indicate that such an experiment is realistic and could be performed in parallel to the main research plan for JUNO, LENA, or RENO-50. Assuming as the starting point the values of the oscillation parameters indicated by the current global fit (in 3 + 1 scenario) and requiring at le…
Numerical solution of a spatio-temporal gender-structured model for hantavirus infection in rodents.
2017
In this article we describe the transmission dynamics of hantavirus in rodents using a spatio-temporal susceptible-exposed-infective-recovered (SEIR) compartmental model that distinguishes between male and female subpopulations [L.J.S. Allen, R.K. McCormack and C.B. Jonsson, Bull. Math. Biol. 68 (2006), 511--524]. Both subpopulations are assumed to differ in their movement with respect to local variations in the densities of their own and the opposite gender group. Three alternative models for the movement of the male individuals are examined. In some cases the movement is not only directed by the gradient of a density (as in the standard diffusive case), but also by a non-local convolution…
Rat liver preservation by hypothermic oscillating liver perfusion compared to simple cold storage.
1998
Rat livers were preserved hypothermically for 10 or 24 h in vitro as if for transplantation. Two methods of preservation were compared using physiological and biochemical parameters: simple storage and oscillating perfusion. By measuring the nucleotides after preservation the calculated energy charge was significantly higher after 10 and 24 h of oscillating perfusion compared to the simple storage group. In addition, a significant energy charge loading was demonstrated by 10 h oscillating perfusion compared to the initial value prior to perfusion. The oscillating, computer-controlled perfusion permits continuous monitoring of perfusate temperature, O2 consumption, pCO2, portal vein pressure…
Subthreshold oscillation of the membrane potential in magnocellular neurones of the rat supraoptic nucleus
2000
The hypothalamic supraoptic nucleus (SON) contains two major populations of magnocellular neurosecretory neurones, producing and secreting vasopressin and oxytocin, respectively (for review see Poulain & Wakerley 1982). Neurones of a subpopulation of supraoptic neurosecretory cells share the capability of generating phasic bursts of action potentials. In these neurones, action potentials are succeeded by a depolarizing afterpotential (DAP; Andrew, 1987; Armstrong et al. 1994; Li et al. 1995). Depending on the discharge frequency, DAPs summate, eventually resulting in the generation of a plateau potential that gives rise to the discharge of a long-lasting train of action potentials. Thus, DA…
Reproducibility of pulse wave velocity and augmentation index derived from non-invasive occlusive oscillometric tonometry analysis in adolescents
2018
The aim of this study was to investigate the short-term reproducibility of aortic pulse wave velocity (PWVao) and augmentation index (AIx%) assessed by the non-invasive oscillometric device. Altogether of 55 (19 boys, 36 girls) adolescents 16-19-years-of-age participated in the study. PWVao and AIx% were measured during the same laboratory visit at 2 min intervals using the Arteriograph™ device. Peak oxygen uptake (VO2peak ) was assessed by the maximal exercise test on a cycle ergometer and body fat percentage by bioelectrical impedance analysis. We studied reproducibility using intraclass correlation coefficients (ICC), coefficient variation with the root-means-square method expressed as p…
Arterial Stiffness and Its Relationship to Cardiorespiratory Fitness in Children and Young Adults with a Fontan Circulation
2019
There are no previous studies on arterial stiffness and its associations with cardiorespiratory fitness in young Fontan patients. Therefore, we examined the arterial stiffness and its relationship to cardiorespiratory fitness in children and young adults with a Fontan circulation. Altogether, 17 Fontan patients and 26 healthy controls (16 females and 27 males aged 8–40 years) participated in this cross-sectional study. The cardiorespiratory fitness was assessed by cardiopulmonary exercise testing on a cycle ergometer and was defined as the standard deviation scores (SDS) of peak oxygen uptake per body mass (VO2peak/kg) based on the national reference values and assessed with cardiopulmonary…
Ambulatory blood pressure and arterial stiffness web-based telemonitoring in patients at cardiovascular risk. First results of the VASOTENS (Vascular…
2019
The VASOTENS Registry is an international telehealth-based repository of 24-hour ambulatory blood pressure monitorings (ABPM) obtained through an oscillometric upper-arm BP monitor allowing combined estimation of some vascular biomarkers. The present paper reports the results obtained in 1200 participants according to different categories of CV risk. Individual readings were averaged for each recording and 24-hour mean of brachial and aortic systolic (SBP) and diastolic blood pressure (DBP), pulse wave velocity (PWV), and augmentation index (AIx) obtained. Peripheral and central BP, PWV and AIx values were increased in older participants (SBP only) and in case of hypertension (SBP and DBP).…
Tissue optical perfusion pressure: a simplified, more reliable, and faster assessment of pedal microcirculation in peripheral artery disease
2020
Oscillometry is an alternative to continuous-wave Doppler (cw-Doppler) to determine peripheral artery disease (PAD) severity using the ankle-brachial index (ABI). cw-Doppler ABI differentiates systolic pressure of ATP and ADP where either one of both values in most patients is higher (high) and the other value is lower (low). In contrast, oscillometric ABI measures the strongest signal and hence misses the lower value. Both do not take pedal perfusion into consideration. Simultaneous determination of tissue microperfusion cares for pedal PAD. ABI was determined by cw-Doppler and oscillometry. Tissue optical perfusion pressure (TOPP) was taken from the first toe using photoplethysmography. 3…