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。     

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.     

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...     

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.     

Between the waves: Harvard Pigeon Lab 1955-1960

Six or more graduate students were active in and around the Pigeon Lab in the spring of 1955 and also in 1960, but when I arrived it the fall of 1955 there were none. Looking back in 2001 at that period I can appreciate the unique opportunity for research that I had, as well as the exceptional and productive groups of graduate students who had recently finished their study and research and those who would carry on the tradition of excellence.     

Interfacial waves between two piezoelectric half-spaces with electro-mechanical imperfect interface

We study the propagation of shear horizontal waves between the interface of two piezoelectric materials with an electro-mechanical imperfect contact. Mechanical and electrical imperfections are modeled by means of a spring and a capacitor, respectively. The corresponding mathematical expressions for the imperfect contact are given in this article. The system of differential equations for the waves in the considered half-space is derived and the associate solutions are found. A general expression for the dispersion relation, not reported previously in the literature, is given in an explicit form, with the diverse limit cases analyzed in detail. In some of these limit cases, new expressions are also obtained, which predict the existence of interfacial waves. In the other cases, where already reported results exist, a comparison with them is done. Some physical interpretations are derived from the limit cases. The influence of mechanical and electrical imperfect contacts are shown in some numerical examples.     

Shear horizontal surface waves in piezoelectric materials with surface stress

ABSTRACT

The propagation of shear horizontal (SH) surface waves in piezoelectric semi-infinite bodies is investigated theoretically. The surface stress exerting on the boundary is taken into account through surface piezoelectricity theory, and the velocity ranges and existence conditions of such surface waves for both electrically open and shorted cases are derived in detail. Analysis results show that the SH surface waves occurring with surface stress are dispersive in contrast to the classical situation, and the propagation characteristics strongly depend on the relative value of surface elasticity, surface piezoelectricity and surface density.     

Interfacial waves between two magneto-electro-elastic half-spaces with magneto-electro-mechanical imperfect interface

The propagation of shear horizontal waves between the interface of two magneto-electro-elastic materials with an magneto-electro-mechanical imperfect contact has been studied. Mechanical, electrical and magnetical imperfections are modelled by means of a spring, a capacitor and an inductor, respectively. A general expression for the dispersion relation is given in an explicit form. Some limit cases are analysed in detail. The influence of imperfect contacts is shown in some numerical results.     

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.     

Interfacial waves between piezoelectric and piezomagnetic half-spaces with magneto-electro-mechanical imperfect interface

Abstract

We study the propagation of shear horizontal waves between the interface of piezoelectric and piezomagnetic half-spaces with a magneto-electro-mechanical imperfect contact. Mechanical, electrical and magnetical imperfections are modelled by means of a spring, a capacitor and a inductor, respectively. A general expression for the dispersion relation not reported previously in literature is given in an explicit form, with the diverse limit cases analysed in detail. In some of these limit cases, new expressions are also obtained which predict the existence of interfacial waves. In the other cases, when already reported results exist, a comparison with them is done. Some physical interpretations are derived from the limit cases. The influence of mechanical, electrical and magnetical imperfect contacts are shown in some numerical examples.     

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.     

The changing UK careers landscape: tidal waves,turbulence and transformation

ABSTRACT

This article explores how the UK careers landscape in each of the four home nations is changing in response to neo-liberal policies. In this context, careers services are increasingly under pressure to demonstrate their added value, impact and returns on investment. As fiscal arrangements tighten and governments state their preferences and priorities for national careers services, differing strategic responses are beginning to emerge. A quasi-market, experimental approach is now the dominant discourse in England, in contrast to differing and complementary arrangements in Northern Ireland, Scotland and Wales. The article suggests that insofar as these developments are transforming national careers services, they are also creating significant challenges which require new forms of policy imagery and imagination for high-impact, all-age careers services.