Intermittent Type Research Articles

Epidemiology of Malignant Melanoma, Worldwide Incidence, and Etiologic Factors

Malignant melanoma is increasing at an alarming rate, exceeding that of any other cancer in the United States today. Genetic susceptibility and exposure to ultraviolet radiation are thought to be the two most important risk factors for development of the neoplasm. While genetic factors cannot be altered, minimizing exposure to ultraviolet light, especially intermittent intense type, and photoprotective measures may significantly reduce the development of this ominous cutaneous malignancy.

TYPE V INTERMITTENCY IN NONDIFFERENTIABLE AND NONINVERTIBLE MAPS

A both nondifferentiable (or discontinuous ) and noninvertible one-dimensional map can display a new type of intermittency. The mechanism of it is that a stable fixed point collides with the nondifferentiable of discontinuous point of the map and then disappears. This type of intermittency can happen in the case when the absolute eigenvalue of the linearised map near the fixed point equals any number smaller than 1 before the intermittency. Therefore, it can appear suddenly in any part between a period-doubling cascade, interrupt the cascade and lead to chaos. In the intermittent time plot after disappearence of the stable fixed point the dura-tion of the laminar phase follows a logarithmic dependence on the distance between a control parameter value and its critical number. This new scaling law is independent of the details of the map. We believe that this new type of intermittency should exist in many practical sys-tems.

Type V intermittency

A new type of intermittency is possible in one-dimensional nondifferentiable (or discontinuous) and noninvertible maps via the collision of a stable fixed point with a nondifferentiable point. This kind of intermittency can happen in any step of a period-doubling cascade. The average laminar phase is logarithmically dependent on the control parameter.

Effect of structural factors on the macro- and micromechanisms of failure of austenitic precipitation-hardening alloys with intermittent type of decomposition. Communication 2

The article shows that fragmented and ultradisperse structures fail with the participation of rotational processes on a scale of the entire specimen.

Factors controlling spontaneous human chorionic gonadotrophin in superfused first trimester placental explants.

We have recently reported that secretion of human chorionic gonadotrophin (HCG) by placental explants in superfusion is pulsatile. In this study, the factors involved in regulation of spontaneous pulsatility were examined. In superfusion, observed secretion of HCG by isolated cells was continuous, without spontaneous episodic hormonal secretion. However, this was not due to diminished viability of the cells since these cells continued to secrete sex steroids. In addition, the stimulatory response of HCG to a highly effective dose of 10(-9) M gonadotrophin releasing hormone (GnRH) analogue was also maintained. Preincubation of explants with low concentrations of cycloheximide (10(-6)M) markedly reduced baseline HCG levels as well as pulse amplitude, suggesting that episodic hormone secretion is in part dependent on protein synthesis. Moreover, preincubation of explants with labelled leucine has shown that the secretion of placental proteins is also episodic in superfusion. The pattern was similar but not identical to that of HCG. Addition of 1 min pulses of CaCl2 caused a significant release of HCG by superfused explants, suggesting that HCG secretion occurs through the release of storage granules. It was concluded that for the expression of spontaneous pulsatile secretion of HCG cell to cell contact/communication is necessary. HCG secretion is likely to reflect exocytosis of storage granules. HCG pulsatility is partly dependent on protein synthesis and this intermittent type of secretion can be documented by overall protein secretion by the superfused explant.

New type of intermittency in discontinuous maps.

Intermittent behavior originating in a point of discontinuity in 1D maps is investigated. Studying the duration of the laminar phase, we find a logarithmic dependence of the average laminar length 〈l〉 on the control parameter \ensuremath{\epsilon}, in contrast to the three conventional types of intermittency characterized by power-law scaling. Analytical considerations give the relation 〈l〉=log(\ensuremath{\epsilon})/log(s)+\ensuremath{\beta} (where s is the ``slope'' at the point of discontinuity). Numerical data obtained from a relaxation oscillator model are in good agreement with these results.

Different types of intermittency observed in transverse-pumped spin-wave instabilities

The dynamic behaviour of magnetization in YIG spheres was studied by FMR within the coincidence regime of the first-order Suhl instability. For certain ranges of the control parameters (magnetic field, microwave frequency and amplitude, etc.) the time-resolved absorption signal shows auto-oscillations changing over to chaos by intermettency. We clearly observed each of the types I–III and rather often crises.

An experimental observation of a new type of intermittency

A novel hysteretic form of regular intermittency has been observed experimentally in a variant of the Taylor-Couette problem where the fluid flow is confined between a stationary outer cylinder and a rotating inner cylinder and end plates. The results cannot all be explained within the standard Pomeau-Manneville classification of intermittency, and an extension to this theory is proposed to account for the observed phenomena. A satisfactory agreement is found between experiment and theory both for the reinjection burst frequency scaling law and the influence of noise on the regularity of the bursts.

Full characterization of a strange attractor: Chaotic dynamics in low-dimensional replicator systems

Two chaotic attractors observed in Lotka-Volterra equations of dimension n = 3 are shown to represent two different cross-sections of one and the same chaotic regime. The strange attractor is studied in the equivalent four-dimensional catalytic replicator network. Analytical expressions are derived for the Lyapunov exponents of the flow. In the centre of the chaotic regime the strange attractor was characterized by the Lyapunov dimension ( D L = 2.06 ± 0.02) and the Rényi fractal dimensions. The set corresponding to the attractor represents a multifractal. Its singularity spectrum is computed. One route in parameter space leading into the chaotic regime and crossing it was studied in detail. It leads to a Feigenbaum-type cascade of bifurcations. Before the chaos is fully developed the dynamic system passes an internal crisis through a period-two tangent bifurcation. Then a second sequence of period-doubling bifurcations leading to another chaotic regime is observed, which eventually ends in a crisis and then after a rather complicated periodic regime the attractor finally disappears. Trajectories in the intermediate periodic regime show transient chaotic bursts of intermittency type. A series of one-dimensional maps is derived from a properly chosen Poincaré cross-section which illustrates structural changes in the attractor. Mutations are included in the catalytic replicator network and the changes in the dynamics observed are compared with the predictions of an approach based on perturbation theory. The most striking result is the gradual disappearance of complex dynamics with increasing mutation rates. The parameter space spanned by the mutation rate and selected parameters of the replication network is split in regions of complex periodic behaviour near the chaotic regime. Fractal boundaries of these regions are likely to occur but the data available do not allow definitive conclusions yet.

Acoustic sounder detection of anabatic/katabatic winds in abisko, N. Sweden

A three-axial acoustic sounder with doppler wind measurements capability has been successfully operated to detect anabatic and katabatic winds in a mountainous and lake-locked region of northern Sweden, Abisko (68°20'N, 18°50'E) between 1 and 2 April 1983. While the flow was predominantly katabatic, two types of anabatic flows were detected: 1. (a) an intermittent type resulting from the action of unsteady wave phenomena and 2. (b) a convectively-induced type resulting from the lifting and erosion of nocturnal inversion as the boundary layer deepens following the input of solar radiation by the sun at dawn. Vertical fluxes of zonal and meridional momentum were calculated. The imprint of gravity wave activity was made manifest by these results and spectral analysis of vertical velocities which were in agreement with observed facsimile record signatures. Observed winds closely follow a modified form of Reiher's 1936 model [M. Reiher, Bioklim Beiblatter 3, 152–163 (1936)].

Fluctuation Spectrum for a New Type of Intermittency in a Coupled Electronic Circuit

A new type of intermittency associated with the transition from uniform to nonuniform chaos in a coupled electronic circuit is studied by means of the fluctuation spectrum theory. The time series are constructed by taking the n -th power of original experimental data obtained near the intermittent transition point. The intermittent behavior is enhanced as the power n is increased. Two types of scaling laws are found for the fluctuation spectra σ(α)'s.

Bifascicular Block and Wolff-Parkinson-White Syndrome

The casual coexistence of ventricular preexcitation with either right or left bundle branch block has been reported by several authors. 1 Pick A Fisch C Ventricular preexcitation (WPW) in the presence of bundle branch block. Am Heart J. 1958; 55: 504-512 Crossref PubMed Scopus (19) Google Scholar , 2 Denes P Goldfinger P Rosen KM Left bundle branch block and intermittent type A preexcitation. Chest. 1975; 68: 356-358 Abstract Full Text Full Text PDF PubMed Scopus (6) Google Scholar , 3 Rakovec P Kranjec I Fettich JJ Association of an accessory pathway and ipsilateral bundle branch block. Int J Cardiol. 1985; 7: 161-164 Abstract Full Text PDF PubMed Scopus (2) Google Scholar , 4 Rakovec P Kranjec I Fettich JJ Jakopin J Fidler V Turk J Wolff-Parkinson-White syndrome type B and left bundle-branch block: Electrophysiologic and radionuclide study. Clin Cardiol. 1985; 8: 51-56 Crossref PubMed Scopus (2) Google Scholar The resulting electrocardiographic pattern is quite different, if the accessory pathway is located in the same side of the heart where the bundle branch block exists, or in the opposite side of the heart. In the former case, the bundle branch block is considered ipsilateral to the anomalous pathway, and in the latter, it is considered to be contralateral. Ipsilateral bundle branch block is masked when preexcitation is present and can be seen occasionally in the electrocardiogram only if the preexcitation is intermittent. The association of preexcitation and contralateral bundle branch block results in wide QRS complexes showing both delta waves and terminal slowing. An unusual combination of bifascicular block and Wolff-Parkinson-White syndrome forms the basis of this report.

Comparison Between Intermittent (Spring-Loaded) and Continuous Closed Suction Drainage of Orthopedic Wounds: A Controlled Clinical Trial

A randomized prospective trial of a continuous vacuum system (VariDyne) and an intermittent spring type system (Hemovac) was conducted in 126 consecutive orthopedic surgical wounds between February 1988 and October 1988 in which postoperative suction drainage was required. Comparison between the two groups showed a statistically significant difference among total drainage removed by the vacuum units and wound drainage into the dressing following drain removal. Hip and knee arthroplasty patients receiving continuous vacuum suction experienced a greater average drainage volume and better wound healing than those receiving the spring-loaded device. Overall, all wounds which utilized continuous vacuum drained less serosanguinous or serous fluid than those wounds utilizing the intermittent system following drain removal. A clear advantage to using a continuous vacuum suction device over an intermittent spring-loaded device is seen with respect to hematoma evacuation, wound drainage, wound healing, and possible complications.

Fatty change in the human temporomandibular joint disc. Light and electron microscopy study

Joint pain has been associated with fatty infiltration of the knee articulation. The purpose of this study is to report on the histopathological findings, especially fatty changes, that are seen in surgical specimens from the temporomandibular joints (TMJ) of patients that had persistent pain after non-surgical therapy. Forty plicated TMJ retrodiscal samples from 25 patients were used in this study. The patients were previously treated with splints for variable periods but not less than 2 months. The specimens were obtained by 2 surgeons using standard TMJ plication techniques. Control disc specimens were obtained from normal appearing cadaveric TM joints. Samples were immediately immersed in glutaraldehyde and processed for light and electron microscopic examination. The specimens were composed mainly of moderately dense tissue with cells that appeared fibroblastic and intermittent chondrocytic type cells. Fatty change, exclusively in association with the perivascular areas, was observed in 27 of 40 specimens. Electron microscopy showed fibroblasts, as well as large fat inclusions adjacent to elastin macroglobules. Fatty infiltration of the TMJ has been interpreted as a degenerative change. It is postulated that kinins and prostaglandins generated in the fat pads can pass freely in tissue fluid to adjacent, highly innervated structures thus leading to joint pain. It is further postulated that the finding of associated elastin with fatty deposition is similar to the atherosclerotic changes encountered in large blood vessels and the aorta.

4818408 Intermittent aeration type biological treatment process and system therefor

4818408 Intermittent aeration type biological treatment process and system therefor

Noise-induced intermittency in the quasiperiodic regime of Rayleigh-B�nard convection

Thermal measurements on a converting dilute3He-superfluid4He solution in the quasiperiodic regime show a transition from a mode-locked periodic state to chaotic time dependence via intermittency. The type of intermittency is discussed in the context of standard models of the phenomenon. In a region just below the onset of intermittency, injection of external multiplicative noise with noise amplitude above a certain threshold level induces the chaotic state. This noise-induced transition can be understood to be due to perturbations of a system with a barely stable attractor; the noise causes the system to escape the weakly attracting periodic points. We present a numerical simulation of a 1D map with external noise which explains some aspects of the noise-induced behavior, and a 2D map which has certain features of the intermittency.

A New Type of Intermittency in an Electronic Circuit

An intermittency which has a different origin from the Pomeau-Manneville types is studied in a coupled nonlinear LCR circuit. This type of intermittency has a close relation to the multiplicative noise process. The electronic circuit is made up of inductors, resistors and capacitor diodes. An experimental study is done in this system. The results are compared with those of a phenomenological theory based on the multiplicative noise process. More· over, a numerical calculation is also carried out on the equations for the present circuit with observed nonlinear characteristics of diodes. Satisfactory agreement between the exper· imental and calculated results is obtained.

Maple syrup urine disease: a possible biochemical basis for the clinical heterogeneity

Nine patients with maple syrup urine disease (MSUD), of whom eight were detected by mass-screening of neonates for inherited metabolic disease, were studied to determine possible relationships between clinical features and properties of the branched-chain alpha-keto acid dehydrogenase complex (BCKDH) in cultured lymphoblastoid cells. Based on their tolerance for leucine and on the clinical manifestations observed after 2 years of age, most could be classified into three types; classical (tolerate less than 600 mg of leucine per day, N = 2), intermediate (N = 3) and intermittent (N = 3) types. In the other patient two of these three phenotypes were present. The BCKDH activities measured at a lower alpha-ketoisovaleric acid concentration (0.054 mM) were 0.026 +/- 0.015 in classical, 0.118 +/- 0.016 in intermediate and 0.625 +/- 0.139 in intermittent types and 7.052 +/- 0.779 (nmol/h per milligram of protein) in two controls, respectively; the differences being statistically significant (P less than 0.01, classical vs intermediate types; P less than 0.01, intermediate vs intermittent types; P less than 0.01, intermittent vs control). Kinetic and immunochemical analyses of the BCKDH revealed that, although there are a few exceptions, classical, intermediate and intermittent types correspond to the enzyme properties of sigmoidal kinetics with E1 beta subunit deficiency, near-sigmoidal kinetics with E1 beta subunit deficiency and hyperbolic kinetics with E2 subunit deficiency of the BCKDH, respectively.

Bifurcations of subharmonics and chaotic motions of articulated towers

The dynamic responses of articulated towers, subjected to regular waves and large motions, are computed numerically using the governing nonlinear differential equations. In certain frequency and system parameter ranges, the motions of the towers are found to exhibit subharmonics and chaotic behaviour which are identified to be the type of intermittency with random alternations of chaotic and regular behaviour in time evolution. The identification, characterization and evaluation of the chaotic motions are performed numerically by studying the discrete trajectories and Poincaré points of the responses. Such chaotic behaviour, if with significant magnitude, can make the responses of the deterministic system random and unpredictable in a practical sense, because the system is extremely sensitive to the initial conditions assumed.

Wave propagation in a one-dimensional quasiperiodic medium: Localization and intermittency.

We consider the propagation of a wave in a quasiperiodic medium whose refractive index exhibits \ensuremath{\delta}-like peaks of equal amplitudes and which are located on quasiperiodic sites. Two specific models of site distributions are investigated. In the first one, we find ``quasilocalized states'' with a very critical definition in energy. In the second model, a particular type of intermittency and a phenomenon of ``noise localization'' appear. The properties of the two models are based on the existence of a slow variable for particular energy values. Experimental applications of the observed resonances are suggested.