浅析心电波形唯一性假说

通过对海量心电图资料的分析,发现每个人的心电图波形绝然不同,均有其自身特点,也即具有唯一性,而同一人的心电波形在出生后至18岁成年前如人的容貌、身高、体重一样变化较大,成年后则相对稳定、基本不变,我们认为心电波形如同其他生物特征一样具有生物特征的显著特点,由此提出心电图心电波形具有唯一性的假说。     

浅析心电波形唯一性假说

通过对海量心电图资料的分析,发现每个人的心电图波形绝然不同,均有其自身特点,也即具有唯一性,而同一人的心电波形在出生后至18岁成年前如人的容貌、身高、体重一样变化较大,成年后则相对稳定、基本不变,我们认为心电波形如同其他生物特征一样具有生物特征的显著特点,由此提出心电图心电波形具有唯一性的假说.     

Point-particle explanations: the case of gravitational waves

Synthese - This paper explores the role of physically impossible idealizations in model-based explanation. We do this by examining the explanation of gravitational waves from distant stellar...     

The evaluation and control of acoustical standing waves

Calibration of a standard pigeon box subsequently modified for use as an acoustical chamber in a frequency discrimination experiment revealed that the enclosure was not acoustically “flat”. Standing waves were detected at each of the six frequencies measured. To ascertain whether the maximum standing waves recorded (3.0 dB) could serve as an added or alternative cue for pigeons tested in the chamber on a frequency discrimination problem, pure-tone intensity difference thresholds were determined for two pigeons at 1.0, 2.0, and 3.0 KHz. The results of the experiment indicated that the smallest intensity difference detectable was 10.0 dB, a value that was 7.0 dB above the maximum standing wave measured in the box. These data suggest that the modified pigeon chamber is suitable to test pure-tone frequency discriminations in pigeons in the range of 1.0 to 3.0 KHz.     

Interfacial shear horizontal waves in a piezoelectric-piezomagnetic bi-material

The propagation of an interfacial shear horizontal (SH) wave is studied in two bonded semi-infinite materials, one piezoelectric and the other piezomagnetic. Both materials are hexagonal (6?mm) crystals. The dispersion relation is given in an explicit form. Based on the obtained dispersion relationship, conditions for the existence of interfacial SH waves are discussed in detail.     

Shear-horizontal surface waves in a half-space of piezoelectric semiconductors

We study the propagation of shear-horizontal waves near the surface of a piezoelectric semiconductor half-space of crystals of class 6 mm with the presence of a biasing electric field in the propagation direction. The three-dimensional equations of linear piezoelectric semiconductors are used. A transcendental equation that determines the dispersion relation is obtained and solved numerically. Results show that the semiconduction affects the wave speed and causes wave dispersion as well as attenuation, and that the waves can be amplified by the biasing electric field.     

Pursuit eye movement in tracking a target with two sine waves

It has been reported that, when subjects track a moving target comprising two sine waves, the tracking lag for the faster sine wave component is much smaller than that for the slower one. To understand this phenomenon further, this study examined frequency characteristics of the human tracking response and pursuit eye movement in response to the target with two sine waves of equal amplitude. Analysis indicates that, while the tracking response has very large phase lag for the slower sine wave component and very small phase lag for the faster one, the pursuit eye movement has a conspicuously large phase lead for the slower component and very small phase lag for the faster one. It is suggested that the lack of synchrony of the pursuit eye movement with slower component of the target may be associated with the inferiority of the slower component to the faster one in tracking lag.     

EEG paroxysmal gamma waves during Bhramari Pranayama: a yoga breathing technique

Here we report that a specific form of yoga can generate controlled high-frequency gamma waves. For the first time, paroxysmal gamma waves (PGW) were observed in eight subjects practicing a yoga technique of breathing control called Bhramari Pranayama (BhPr). To obtain new insights into the nature of the EEG during BhPr, we analyzed EEG signals using time-frequency representations (TFR), independent component analysis (ICA), and EEG tomography (LORETA). We found that the PGW consists of high-frequency biphasic ripples. This unusual activity is discussed in relation to previous reports on yoga and meditation. It is concluded this EEG activity is most probably non-epileptic, and that applying the same methodology to other meditation recordings might yield an improved understanding of the neurocorrelates of meditation.     

Sanderian activation waves: a hypothesis of a nonsymbolic influence on moods

This paper describes a hypothesis of Tronick's (2002) that positive and negative affect activation waves with changing amplitudes based on positive and negative lived experiences are the sources of persistent or regularly recurrent moods of feeling upbeat or downbeat. The characteristics of discrete affects, moods, and affect states are discussed in the light of a previous study based on clinical observation (Lichtenberg, Lachmann, and Fosshage 1996). The clinical experience theory underpinning that study is then compared with Tronick's Sanderian activation wave theory. A case example is presented, and the overall relevance of Tronick's theory to clinical work is discussed.     

Frequency pattern of alpha waves in the early stages of cerebrovascular circulation disorders]

In this study 201 EEG curves are interpreted belonging to patients suffering from incipient disturbances of the cerebral circulation. The patients were divided into 3 groups according to age (group I, 30-40 years; group II, 40-50 years; group III, 50 years and over). In group I there prevailed a rate of 11-12 alpha waves per sec., and a slower rate was hardly ever found; in group III the frequency pattern was quite different. This decreased frequency of the waves could be confirmed by statistics. We believe a direct link can be assumed to exist between a decrease in frequency and the beginning of disturbed cerebral circulation.     

Detection of P300 waves in single trials by the wavelet transform (WT)

The P300 response is conventionally obtained by averaging the responses to the task-relevant (target) stimuli of the oddball paradigm. However, it is well known that cognitive ERP components show a high variability due to changes of cognitive state during an experimental session. With simple tasks such changes may not be demonstrable by the conventional method of averaging the sweeps chosen according to task-relevance. Therefore, the present work employed a response-based classification procedure to choose the trials containing the P300 component from the whole set of sweeps of an auditory oddball paradigm. For this purpose, the most significant response property reflecting the P300 wave was identified by using the wavelet transform (WT). The application of a 5 octave quadratic B-spline-WT on single sweeps yielded discrete coefficients in each octave with an appropriate time resolution for each frequency range. The main feature indicating a P300 response was the positivity of the 4th delta (0.5-4 Hz) coefficient (310-430 ms) after stimulus onset. The average of selected single sweeps from the whole set of data according to this criterion yielded more enhanced P300 waves compared with the average of the target responses, and the average of the remaining sweeps showed a significantly smaller positivity in the P300 latency range compared with the average of the non-target responses. The combination of sweeps classified according to the task-based and response-based criteria differed significantly. This suggests an influence of changes in cognitive state on the presence of the P300 wave which cannot be assessed by task performance alone.     

Breaking the waves: age differences in electrical brain activity when reading text with distractors

The authors tested whether older adults have greater difficulty than younger adults in ignoring task-irrelevant information during reading as a result of age-related decline in inhibitory processes. Participants were shown target sentences containing distractor words. They were instructed to read aloud each sentence and ignore distractors. The N400 event-related potential (ERP) was used to measure the extent of semantic processing of target and distracting information. It showed that younger adults semantically processed both target and distracting material, whereas online processing of target sentences in older adults was disrupted by the distractors. In older adults, memory for target information related to their susceptibility to distraction and inhibition efficiency. Implications for age-differences in inhibitory control, working memory, and resource capacity are discussed.     

Microgenetic patterns of children's multiplication learning: confirming the overlapping waves model by latent growth modeling

Variability in strategy selection is an important characteristic of learning new skills such as mathematical skills. Strategies gradually come and go during this development. In 1996, Siegler described this phenomenon as "overlapping waves." In the current microgenetic study, we attempted to model these overlapping waves statistically. In addition, we investigated whether development in strategy selection is related to development in accuracy and to what degree working memory is related to both. We expected that children with poor working memory are limited in their possibilities to make the associations that are necessary to progress to more mature strategies. This limitation would explain the often-found relationship between working memory and mathematical abilities. To this aim, the strategy selection and accuracy of 98 children who were learning single-digit multiplication was assessed eight times on a weekly basis. Using latent growth modeling for categorical data, we confirmed Siegler's hypothesis of overlapping waves. Moreover, both the intercepts and the slopes of strategy selection and accuracy were strongly interrelated. Finally, working memory predicted both strategy selection and accuracy, confirming that working memory is related to mathematical problem solving in two ways because it influences both the maturity of strategy choice and the probability of making procedural mistakes.