The purpose of this study was to examine the pulse wave velocity, aortic augmentation index corrected for heart rate 75 (AIx@75), and central systolic and diastolic blood pressure during 24-hour monitoring in normotensive volunteers. Overall, 467 subjects (206 men and 261 women) were recruited in this study. Participants were excluded from the study if they were less than 19 years of age, had blood test abnormalities, had a body mass index greater than 2 7.5 kg/m(2), had impaired glucose tolerance, or had hypotension or hypertension. Ambulatory blood pressure monitoring (ABPM) with the BPLab(®) device was performed in each subject. ABPM waveforms were analyzed using the special automatic Vasotens(®) algorithm, which allows the calculation of pulse wave velocity, AIx@75, central systolic and diastolic blood pressure for "24-hour", "awake", and "asleep" periods. Circadian rhythms and sex differences in these indexes were identified. Pending further validation in prospective outcome-based studies, our data may be used as preliminary diagnostic values for the BPLab ABPM additional index in adult subjects.
OBJECTIVES: The purpose of this research was to study possible abnormalities in the beat to beat complexity of heart rate dynamics in patients with a previous myocardial infarction. BACKGROUND: Analysis of approximate entropy of time series data provides information on the complexity of both deterministic and random processes. It has been proposed that regularity or loss of complexity of RR interval dynamics may be related to pathologic states, but this hypothesis has not been well tested in cardiovascular disorders. METHODS: Approximate entropy and conventional time and frequency domain measures of RR interval variability were compared between 40 healthy subjects with no evidence of heart disease and 40 patients with coronary artery disease and a previous Q wave myocardial infarction. The groups were matched with respect to age, and cardiac medication was discontinued in the patients with coronary artery disease before the 24-h electrocardiographic recordings. RESULTS: Approximate entropy was significantly higher in the postinfarction patients (1.21 +/- 0.18 [mean +/- SD]) than in the healthy subjects (1.05 +/- 0.11, p
Fixed passive acoustic monitoring can be used for long-term recording of vocalizing cetaceans. Both presence monitoring and animal density estimation requires the call rates and sound source levels of vocalizations produced by single animals. In this study, blue whale calls were recorded using acoustic bio-logging systems in Skjálfandi Bay off Húsavík, Northeast Iceland, in June 2012. An accelerometer was attached to individual whales to monitor diving behavior. During 21?h recording two individuals, 8?h 45?min and 13?h 2?min, respectively, 105 and 104 lunge feeding events and four calls were recorded. All recorded calls were down-sweep calls ranging from 105 to 48?Hz. The sound duration was 1-2?s. The source level was estimated to be between 158 and 169?dB re 1µPa rms, assuming spherical sound propagation from the possible sound source location to the tag. The observed sound production rates and source levels of individual blue whales during feeding were extremely small compared with those observed previously in breeding grounds. The feeding whales were nearly acoustically invisible. The function of calls during feeding remains unknown.
Masking from industrial noise can hamper the ability to detect marine mammal sounds near industrial operations, whenever conventional (pressure sensor) hydrophones are used for passive acoustic monitoring. Using data collected from an autonomous recorder with directional capabilities (Directional Autonomous Seafloor Acoustic Recorder), deployed 4.1?km from an arctic drilling site in 2012, the authors demonstrate how conventional beamforming on an acoustic vector sensor can be used to suppress noise arriving from a narrow sector of geographic azimuths. Improvements in signal-to-noise ratio of up to 15?dB are demonstrated on bowhead whale calls, which were otherwise undetectable using conventional hydrophones.
Masking from industrial noise can hamper the ability to detect marine mammal sounds near industrial operations, whenever conventional (pressure sensor) hydrophones are used for passive acoustic monitoring. Using data collected from an autonomous recorder with directional capabilities (Directional Autonomous Seafloor Acoustic Recorder), deployed 4.1?km from an arctic drilling site in 2012, the authors demonstrate how conventional beamforming on an acoustic vector sensor can be used to suppress noise arriving from a narrow sector of geographic azimuths. Improvements in signal-to-noise ratio of up to 15?dB are demonstrated on bowhead whale calls, which were otherwise undetectable using conventional hydrophones.
The paper presents data on the formation of spatial synchronization of brain potentials in 91 children aged 7-18 years living in European North of Russia. We estimated coherence values for 19 derivations (pair 171) in five EEG frequency bands (delta, theta, alpha-1, alpha-2 and beta). We described age-related changes, gender differences and topical specific features of the formation of coherence in the left and right hemispheres, and in inter- and intrahemispheric synchronization. We carried out computer assessment of the differences in EEG coherence between three age groups of children in order to determine criteria for identification of children with retarded formation of spatial organization of local EEG processes. Age-related changes in the structure of EEG patterns observed in the study reflect the processes of morphofunctional brain development in children and adolescents at different stages of postnatal ontogenesis under severe conditions of northern climate.
Opioids alter resting state brain oscillations by multiple and complex factors, which are still to be elucidated. To increase our knowledge, multi-channel electroencephalography (EEG) was subjected to multivariate pattern analysis (MVPA), to identify the most descriptive frequency bands and scalp locations altered by remifentanil in healthy volunteers. Sixty-two channels of resting EEG followed by independent measures of pain scores to heat and bone pain were recorded in 21 healthy males before and during remifentanil infusion in a placebo-controlled, double-blind crossover study. EEG frequency distributions were extracted by a continuous wavelet transform and normalized into delta, theta, alpha, beta and gamma bands. Alterations relative to pre-treatment responses were calculated for all channels and used as input to the MVPA. Compared to placebo, remifentanil increased the delta band and decreased the theta and alpha band oscillations as a mean over all channels (all p = 0.007). The most discriminative channels in these frequency bands were F1 in delta (83.33%, p = 0.0023) and theta bands (95.24%, p
Measurements covering a broad frequency range from 100 Hz to 80 kHz have been made in Behm Canal, Alaska. This site represents a fairly deep embayment (400 m) with a soft bottom (porosity of about 0.8) and, hence, the noise detected at the hydrophones is affected negligibly by multipath contributions except possibly at the lowest frequencies. Data were gathered over a wide range of wind speeds (0 to 15 m/s) and during periods of rain and snow. Several unique and noteworthy results were obtained. Foremost was the observation that the wind-generated noise level measured during the winter was approximately 5 dB lower than during the summer for the same wind speeds and air-sea temperature differences (air temperature about the same as or colder than the sea surface). The summer data agree well with the most recent published measurements and are approximately 2 dB higher than the standard Knudsen/Wenz reference spectra. It appeared that below-freezing air temperatures and snow were responsible for the 5 dB offset between the summer and winter data. Most reported wind noise measurements are restricted to frequencies less than 20 kHz. Those that go beyond this frequency display a noticeable hump above the usual--17 dB/decade power-law slope, and the Behm Canal measurements show that this hump continues to 80 kHz where the spectrum rejoins the extension of the canonical power-law slope.
This study analyses results from the first Swedish UNHS program. It includes over 33 000 measurement files from 14 287 children at two maternity wards. The screening program uses a two-stage TEOAE test procedure. A database was created in MedLog after data transformation in Word and Excel. The coverage rate was 99.1%. Bilateral pass rate after retesting was 97.0%. A unilateral pass criterion would have resulted in 1268 fewer children (9.0% of target group) for retesting and 231 fewer children (1.6% of target group) for diagnostic evaluation. When the first test was performed on the day the child was born, the pass rate was 64.8%; the pass rate increased to 89.2% when testing> or =3 days after birth. High coverage rates and pass rates were found to be possible, independent of the number of children born at the maternity ward. Learning curves were observed in the program with improvements distributed over time. Test performance was clearly better when the children were tested day two after birth or later.
In order to analyze balance control, we developed a new inclinometry-based method to provide direct information about body sway in the side-to-side and forward-backward directions. We tested the clinical utility of this method for analyzing balance in Parkinson's disease (PD), and studied the clinical correlates of the balance measures in PD. Postural sway was measured during quiet stance with eyes open and eyes closed in 28 PD patients and in 32 age- and sex-matched control subjects. Postural sway was modeled using side-to-side and forward-backward directional sway movements, sway velocity, and sway area. The amount of postural sway in the PD patients was greater than in the control subjects, the higher level being most marked in patients with severe or long-duration PD. All the side-to-side directional sway parameters were abnormal in the PD patients compared with the control subjects (P
