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PubMed1993

Emotions in the sight of long-time averaged spectrum and three-dimensional analysis of periodicity.

The authors used long-time averaged spectrum and three-dimensional analysis of periodicity (3D-PAN) for analyzing emotional expressions in utterances. They confirmed the movement of the skewness of formant region, that is getting smaller at anger and at joy. It can reach positive values. The skewness is higher at sadness. These findings correspond to the physiological phenomena that we can follow in the whole musculature. The 3D-PAN has not brought any new finding as far.

Computer Graphics↗
PubMed1993

Period-amplitude analysis and power spectral analysis: a comparison based on all-night sleep EEG recordings.

Both period-amplitude analysis (PAA) and power spectral analysis (PSA) were performed on all-night human sleep EEG recordings obtained from 11 subjects. The comparison of the two methods was based on the PAA variables time in band (a wave incidence measure) and rectified amplitude, and on the PSA variables spectral power density and spectral amplitude (the square root of power). The mean time course of these variables was determined for the first 4 nonREM-REM sleep cycles. Spectral power density and spectral amplitude in the delta range were high in nonREM sleep and low in REM sleep, and showed a declining trend over consecutive nonREM sleep episodes. In the frequency range below 2 Hz, rectified amplitude was highly correlated with both time in band and spectral amplitude, and there was no evidence for a dissociation between wave amplitude and wave incidence measures. However, in frequencies above 2 Hz, the modulation of time in band was a mirror image of that below 2 Hz. This result does not reflect a property of the data, but is inherent to the methodology applied. The reversal point of modulation was merely shifted when the high-pass filter settings were changed. It is concluded that band-pass filtering is necessary prior to PAA even for the analysis of the lowest frequency range, and that the indiscriminate use of PAA may give rise to spurious results.

Journal Article↗
PubMed1985

Statistical age-period-cohort analysis: a review and critique.

Descriptive and statistical age-period-cohort (APC) analysis methods have received considerable attention in the literature. The statistical modeling of APC data often involves the popular multiple classification model, a model containing the effects of age groups (rows), periods of observation (columns), and birth cohorts (diagonals of the age-by-period table). The identifiability problem inherent to this model is discussed, and its adverse effects on the results of APC modeling exercises are illustrated numerically. Potential problems attendant with the use of two-factor models are described, and other possible modeling approaches currently in use are discussed. Interpretational limitations due to certain innate characteristics of typical APC data sets are also detailed. Given all the documented potential sources for error, the current state-of-the-art regarding the statistical modeling of APC data should be considered to be at an early stage of development.

Adult↗
PubMed1999

Global analysis of periodic orbit bifurcations in coupled Morse oscillator systems: time-reversal symmetry, permutational representations and codimension-2 collisions.

In this paper we study periodic orbit bifurcation sequences in a system of two coupled Morse oscillators. Time-reversal symmetry is exploited to determine periodic orbits by iteration of symmetry lines. The permutational representation of Tsuchiya and Jaffe is employed to analyze periodic orbit configurations on the symmetry lines. Local pruning rules are formulated, and a global analysis of possible bifurcation sequences of symmetric periodic orbits is made. Analysis of periodic orbit bifurcations on symmetry lines determines bifurcation sequences, together with periodic orbit periodicities and stabilities. The correlation between certain bifurcations is explained. The passage from an integrable limit to nointegrability is marked by the appearance of tangent bifurcations; our global analysis reveals the origin of these ubiquitous tangencies. For period-1 orbits, tangencies appear by a simple disconnection mechanism. For higher period orbits, a different mechanism involving 2-parameter collisions of bifurcations is found. (c) 1999 American Institute of Physics.

Journal Article↗
PubMed1993

[Balloon (Rashkind) atrio-septostomy in transposition of great vessels in the neonatal period].

Analysis of the balloon atrial septostomy (BA) for treatment of the transposition of the great arteries (TVG) during the neonatal period will allow the evaluation of some of the changes that have occurred in the diagnosis and therapy of this congenital cardiopathy. We performed a retrospective survey of the management, evolution complications of 24 BA as a palliative technique in TGV cases, admitted to the Neonatal Intensive Care Unit during a 5 1/2 year period. The aim of the study was to evaluate the factors that indicated a bad prognosis by comparing patients that are still alive (21) with those that are dead (3). The mean age at BA performance was 4.5 +/- 5.5 days. The biological constants prior to catheterization were normal, maintaining good oxygenation, administering prostaglandins in 80% of the patients and mechanical ventilation in 25% of the patients. BA outcome was considered as good in 68%, moderate in 12% and bad in 20% of the cases. Intra-catheterization complications, mainly hemorrhages and bradycardia, were suffered by 40% of the patients and one patient died during catheterization. We could see a progressive arterial desaturation due to the lack of efficacy of the BA. As bad post-catheterization outcome factors were found: hypotension, arrhythmia, hemorrhage, greater need of dobutamine, volume expansion and mechanical ventilation. Our principal conclusion is that, although BA has improved the prognosis of newborns with TGV, because of the progressive worsening of the patients during the months following the BA, it is necessary to perform early corrective surgery.

Catheterization↗
PubMed1999

A comparison of period amplitude analysis and FFT power spectral analysis of all-night human sleep EEG.

Zero-cross and zero-derivative period amplitude analysis (PAA) data were compared with power spectral analysis (PSA) data obtained with the fast Fourier transform in all-night sleep EEG from 10 subjects. Although PAA zero-cross-integrated amplitude showed good agreement with PSA power in 0.3-2 Hz, zero-cross analysis appears relatively ineffective in measuring 2-4 Hz and above waves. However, PAA zero-derivative measures of peak-trough amplitude correlated well with PSA power in 2-4 Hz. Thus, while PAA appears able to measure the entire EEG spectrum, the analytic technique should be changed from zero cross to zero derivative at about 2 Hz in human sleep EEG. PAA and PSA both demonstrate robust and interrelated across-night oscillations in three frequency bands: delta (0.3-4 Hz); sigma (12-16 Hz); and fast beta (20-10 Hz). The frequencies between delta and sigma, and between sigma and fast beta, did not show clear across-night oscillations using either method, and the two methods showed lower epoch-to-epoch agreement in these intermediate bands. The causes of this reduced agreement are not immediately clear, nor is it obvious which method gives more valid results. We believe that the three strongly oscillating frequency bands represent fundamental properties of the human sleep EEG that provide important clues to underlying physiological mechanisms. These mechanisms are more likely to be understood if their dynamic properties are preserved and measured naturalistically rather than being forced into arbitrary sleep stages or procrustean models. Both PAA and PSA can be employed for such naturalistic studies. PSA has the advantages of applying the same analytic method across the EEG spectrum and rests on more fully developed theory. Combined zero-cross and zero-derivative PAA demonstrates EEG oscillations that closely parallel those observed with spectral power, and the PAA measures do not rely on assumptions about the spectral composition of the signal. In addition, both PAA techniques can measure the relative contributions of wave amplitude and incidence to total power: These waveform characteristics represent different biological processes and respond differentially to a wide range of experimental conditions.

Adult↗
PubMed1979

[Occurrence of giant nucleolar fibrillar centers in neurons of rat superior cervical ganglia during dark period: sterological analysis].

In the rat, fibrillar centers (nucleolar organizers) of neurons in superior cervical ganglia are small during light period whereas quite giant ones are observed during dark period. Stereological analysis demonstrates that mean volume of fibrillar centers which is 11.9 x 10(-2) micron 3 in light period increases up to 159 x 10(-2) micron 3 in dark period. So, the more or less development of fibrillar centers in these interphasic nuclei is a circadian phenomenon.

Animals↗
PubMed2002

Efficient analysis of periodic dielectric waveguides using Dirichlet-to-Neumann maps.

We present a numerical scheme for the analysis of periodic dielectric waveguides using Floquet-Bloch theory. The problem of finding the fundamental propagation modes is reduced to a nonlinear eigenvalue problem involving Dirichlet-to-Neumann maps. This approach leads to much smaller matrix problems than the ones that have appeared previously. By an increase of the discretization fineness, any desired precision of the method can be achieved. We discuss an eigensolver and extend the conventional rule to choose the branches of the transverse wave numbers. This ensures analytic dependence on the Floquet multiplier and convergence of the nonlinear solver. We demonstrate that even for a complicated multilayer waveguide structure the propagation factors can be calculated within seconds to several digits of accuracy.

Journal Article↗
PubMed2004

Mortality trends of multiple sclerosis in Spain, 1951-1997: an age-period-cohort analysis.

Trends of multiple sclerosis mortality in Spain from 1951 to 1997 are examined. Age-adjusted mortality strongly decreased from 3.08 per 100,000 women in 1951-1967 to 0.59 in 1968-1980 (similar figures were obtained for men). This decrease seems to be due to an artifact produced by changes in codification of causes of death. An age-period-cohort analysis, limited to the period 1968-1997, showed that the mortality trend in Spain cannot be fully explained by year of death (period effect), but that a cohort (year of birth) effect is also necessary. An increase in mortality related with the cohort of birth was detected: people born after 1953 had double the risk of those born between 1938 and 1947, and four times the risk of those born between 1923 and 1932. Regarding the period effect, there is a decrease in mortality, probably due to improvements in life expectancy of multiple sclerosis patients.

Adult↗
PubMed2004

Periodic orbit analysis reveals subtle effects of atropine on epileptiform activity in the guinea-pig hippocampal slice.

Epileptiform activity is a state often induced in vitro in order to study seizures and antiepileptic/anticonvulsant drugs. Traditional methods of evaluating drug effects have commonly relied upon measuring changes in the frequency and duration of such events. We have used a recently developed mathematical technique based on periodic orbit analysis to investigate the effect of atropine (a muscarinic antagonist) on epileptiform activity induced by soman (an irreversible acetylcholinesterase inhibitor), 4-aminopyridine (a K+ channel blocker) and 8-cyclopentyl-1,3-dipropylxanthine (an adenosine A1 receptor antagonist) in the guinea-pig hippocampal slice. This technique showed that significant changes in periodic orbits can occur without an accompanying change in burst rate. These results suggest that periodic orbit analysis may be useful in detecting and predicting novel actions of anticonvulsant drugs.

4-Aminopyridine↗
PubMedDate not supplied

[Possibilities of management of dyspeptic symptoms in the immediate postoperative period].

Analysis of the postoperative course of 1276 patients has shown that the incidence of nausea and vomiting in the first hours after surgical intervention does not depend on the mode of analgesia. Dyspepsia in the immediate postoperative period occurred in more than 1/3 of the patients after surgery on the bile duct. Addition of metoclopramide or dimetpromide to premedication helped reduce the incidence of postoperative vomiting. An antiemetic drug should be an obligatory component of premedication.

Dyspepsia↗
PubMed1998

Nonlinear dynamical analysis of periodic lateralized epileptiform discharges.

Nonlinear time series analysis can be used to investigate the dynamics underlying the generation of EEG signal. In the present study we used this approach to study the pathophysiology of PLEDs. We calculated the correlation dimension D2 of an EEG with typical PLEDs, and compared the results with those obtained for surrogate data. These surrogate data have the same power spectrum and amplitude distribution as the original EEG data, but are otherwise random. By construction, such surrogate data can be described by a linear model. Our results showed that D2 estimations for PLEDs were low, on the order of one, and that the results for EEG and the surrogate data were clearly different, indicating that the EEG with PLEDs reflects nonlinear dynamics of the underlying neural networks.

Electroencephalography↗
PubMed2005

Significant difference in the trends of female breast cancer incidence between Taiwanese and Caucasian Americans: implications from age-period-cohort analysis.

Female invasive breast cancer (FIBC) in Taiwan is characterized by a striking recent increase of incidence and a relatively young median age (45-49 years) at diagnosis. The Westernization of lifestyle that is increasingly affecting younger generations of Taiwanese may have an important impact on this change. We compared epidemiologic data on FIBC in Taiwanese obtained from the Taiwan Cancer Registry with data for Caucasian Americans obtained from the database of the Surveillance, Epidemiology, and End Results Program for the period from 1980 to 1999. Age-specific incidence rates of FIBC were plotted by calendar year at diagnosis and by birth cohort for both populations. The individual effects of time period and birth cohort on the incidence trends of FIBC in both populations were evaluated using the age-period-cohort analysis. The incidence rate of FIBC was continuously increased in Taiwanese throughout the past 2 decades, whereas the increase of incidence was slowing down in Caucasian Americans. The incidence rates in Taiwanese women born after the 1960s were approaching that of Caucasian Americans. The age-period-cohort analysis showed a much stronger birth cohort effect on the incidence trend of FIBC in Taiwanese than in Caucasian Americans. This strong birth cohort effect corresponded to the Westernization of lifestyle in Taiwan since 1960. These findings indicate that a continued shift in the incidence and age distribution pattern of FIBC in Taiwanese toward that of Caucasian Americans should be anticipated.

Adult↗
PubMedDate not supplied

[The pathogenetic and treatment problems of multiple organ failure in patients with severe combined trauma and massive blood loss in the early postresuscitation period].

Analysis of the results of treatment of 583 patients with grave and terminal stages of shock resultant from severe combined injuries and blood loss, hospitalized in resuscitation wards, showed visceral involvement and development of pyoinflammatory complications in the early postresuscitation period (days 5-10 of treatment) in 43.6% cases. Prolonged mixed type hypoxia and persistence of impaired tissue perfusion, shown by rheovasography, play an important role in the mechanisms of development of complications. Early onset (6-8, 10-12 h after the beginning of treatment) and long standing of disseminated intravascular coagulation (DIC) contributes to the pathogenesis of polyorgan failure. A protocol of pathogenetically validated measures for the prevention and treatment of DIC is presented as one of approaches to the prevention and treatment of polyorgan failure.

Combined Modality Therapy↗
PubMed1987

Age-period-cohort analysis of secular trends in onset of major depression: findings in siblings of patients with major affective disorder.

Analyses of data from the NIMH-CRB Collaborative Depression Study on age at onset of Major Depressive Disorder (MDD) in 1144 directly interviewed siblings of patients with major affective disorder show a strong secular trend toward increased lifetime risk and earlier onset in successive cohorts of birth since 1930. The proportionate increases in the instantaneous probabilities (hazard) of onset of MDD for each one year difference in year of birth were 5% for brothers and 7% for sisters. Age-period-cohort analysis suggests a powerful period effect may be responsible for this secular trend in rates of MDD, with rates of onset for siblings between 15 and 50 years of age doubling between the 1960s and 1970s. Possible artifacts are investigated.

Adolescent↗
PubMed1984

EEGs during high-dose fentanyl-, sufentanil-, or morphine-oxygen anesthesia.

In 49 patients undergoing open-heart surgery we compared the electroencephalographic (EEG) effects of high-dose morphine, fentanyl, or sufentanil with O2, using two computerized analysis and display techniques: a period analysis (the Klein method) and an aperiodic analysis (the Neurometrics monitor). During fentanyl or sufentanil anesthesia, both techniques revealed a general decrease in frequency, shown by the aperiodic analysis primarily as a marked increase in the very low frequency range: an increase in the 1-Hz bin (TP1, in muv2) from 2.80 X 10(4) +/- 3.20 X 10(4) (SD) to 45.1 X 10(4) +/- 27.2 X 10(4) for fentanyl and from 3.11 X 10(4) +/- 2.83 X 10(4) to 52.8 X 10(4) for sufentanil. The cumulative percent power at 3 Hz (CP3) increased from 27.2 +/- 6.8 to 83.0 +/- 11.0 for fentanyl and from 22.7 +/- 5.2 to 85.1 +/- 10.4 for sufentanil, while the frequency at 90% cumulative percent power (F90, in Hz) decreased from 17.8 +/- 2.9 to 7.9 +/- 2.8 for fentanyl and 16.4 +/- 5.2 to 5.6 +/- 4.3 for sufentanil. The changes with morphine were less obvious, with some attenuation of high-frequency power shown by the Klein method, and an increase from 24.1 +/- 8.6 to 59.3 +/- 20.7 with CP3, but no change in TP1. Low-frequency power with the period analysis and TP1 with the aperiodic analysis decreased between laryngoscopy and the incisions with fentanyl and sufentanil.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2007

Breastfeeding and infant eczema in the first year of life in the KOALA birth cohort study: a risk period-specific analysis.

OBJECTIVE: We studied the association between breastfeeding and eczema, taking into account the possible influence of reverse causation, with risk period-specific analyses. METHODS: Information on breastfeeding, determinants, and outcomes at 1 year of age was collected with repeated questionnaires for 2405 mother-infant pairs participating in the KOALA (Child, Parent and Health: Lifestyle and Genetic Constitution [in Dutch]) birth cohort study. By using multivariate logistic regression analysis, we compared an overall analysis with risk period-specific analyses. RESULTS: By the age of 1 year, 535 infants (22.2%) had developed eczema. In an overall analysis, we found a weak nonsignificant trend toward a reduced risk of eczema in the first year of life with increasing duration of breastfeeding (lowest risk for those breastfed for > or = 7 months versus never breastfed). In the risk period-specific analysis (confined to infants "at risk" for eczema onset after 3 months of age), no indication for reverse causation was found (results were not very different, compared with the overall analysis). Infants who were breastfed from birth on had a slightly (although not statistically significantly) increased risk for eczema in the first 3 months of life, compared with infants who were formula fed from birth on. CONCLUSIONS: Our results indicated that no strong effect of breastfeeding on eczema in the first year of life was present. This conclusion was strengthened by risk period-specific analysis, which made the influence of reverse causation unlikely.

Breast Feeding↗
PubMed1990

Morphology and development of the terminal portion of the abdominal aorta in cow during fetal and neonatal periods.

Analysis of morphological and developmental features of arteries forming the terminal portion of the aorta was performed. These are the external iliac, umbilical, median sacral, ovarian, caudal mesenteric and lumbar arteries. In the earliest fetuses slow rate of development of the branches of aorta is stated. However, beginning from 13th week ot gestation the rate increases causing considerable developmental and individual variability of the vessels. At the end of the fetal period and in newborns a decrease in the rate of the development of the terminal portion of the aorta is typical for the species and sex except individual variability of its secondary branches.

Animals↗