The relationship between precursor level and the temporal effect

Previous studies have suggested that temporal effects in masking may be consistent with a decrease in cochlear gain. One paradigm used to show this is to measure the level of a long-duration masker required to just mask a short-duration tone that occurs near masker onset. The temporal effect is revealed when the signal is detected at a lower signal-to-noise ratio following preceding stimulation (either an extension of the masker or a separate precursor). The present study examined whether this effect depends on precursor level. The signal was a 10-ms, 4-kHz tone. The masker was 200 ms. A fixed-level precursor had the same frequency characteristics as the masker, and was 205 ms. The masker and precursor had either no notch or a wide notch about the signal frequency. For a given precursor level, the growth of masker level with signal level was determined. These data were used to estimate input-output functions. The results are consistent with a graded decrease in gain at the signal frequency when there is no notch in the masker and precursor, and a graded decrease in suppression when there is a large notch. These results could be consistent with the action of the medial olivocochlear reflex.     

The relationship between magnetic and electrophysiological responses to complex tactile stimuli

Background  

Magnetoencephalography (MEG) has become an increasingly popular technique for non-invasively characterizing neuromagnetic field changes in the brain at a high temporal resolution. To examine the reliability of the MEG signal, we compared magnetic and electrophysiological responses to complex natural stimuli from the same animals. We examined changes in neuromagnetic fields, local field potentials (LFP) and multi-unit activity (MUA) in macaque monkey primary somatosensory cortex that were induced by varying the rate of mechanical stimulation. Stimuli were applied to the fingertips with three inter-stimulus intervals (ISIs): 0.33s, 1s and 2s.     

The spatial and temporal development of pseudospark switch plasmas

Optical spectroscopy is used to investigate the spatial and temporal development of high-current pseudospark switch plasmas. At a peak discharge current of 12 kA in amplitude and a current reversal of 20%, the electron density is measured from Stark width broadening of the hydrogen Balmer beta line. The peak electron density of ~4×10¹⁵ cm^-3 is measured briefly after the current maximum. The discharge initially starts on the symmetry axis of the cathode hole. A cylindrical plasma column is observed, which is produced mainly by ionizing collisions of beam electrons formed in the hollow cathode during the early part of the discharge. This plasma column rapidly expands in the radial direction, until it contacts the edge of the cathode hole. The same behavior is found when the Balmer beta line intensity is evaluated rather than the line shape. Although statistically distributed, localized bursts of light are found occasionally, an axially symmetric, homogeneous light intensity distribution is always predominant, and the local arcing is merely superimposed on it. These results confirm that the discharge remains diffuse during most of the current pulse     

Physical mechanisms for the development of lightning discharges between a thundercloud and the ionosphere

An investigation is made of the influence of changes in atmospheric pressure with altitude and the thundercloud geometry on the development of lightning propagating upward to the ionosphere. It is shown that the mechanism for the development of high-altitude lightning does not differ from that for the formation and propagation of ordinary lightning between a thundercloud and the ground. It is established that high-altitude lightning forms as a result of a reduction in pressure with altitude and can only take place from thunderclouds located at high altitudes. Zh. Tekh. Fiz. 69, 134–137 (April 1999)     

多模Ar^＋激光时间相干性与输出功率的关系

本文就多纵模Ar~+激光时间相干性(即相干长度)与输出功率的关系进行了实验观测,得到了相干长度与输出功率关系近似为双曲线函数的实验结果,并根据简单的Smith模型,对多纵模激光的时间相干性与输出功率进行了理论分析与数值计算.研究结果表明,理论与实验结果基本吻合.     

Kinetic model for the relationship between mean diameter shortening and age reduction in glass samples

Fission tracks in glass samples are shortened when they experience thermal treatment. Consequently, the observable dimensions associated with track length also diminish. The dimension normally used to characterize track size is the mean diameter of the etched track at the surface, D. Another consequence of length shortening is the reduction of surface density, ρ, implying a reduction of the fission-track age. In this work, a kinetic model is developed to describe the relationship between fission-track mean diameter shortening and surface fission-track density reduction in glass samples, based on geometrical and etching hypotheses. The result is a two-parameter equation given by

(1)

in which h is the thickness of the layer removed during etching and n is a parameter related to the latent track geometry and etching reaction rate. The equation was compared with experimental data on Australite glass found in the literature and with fresh data on Macusanite glass presented in this work. The model fits the experimental curves quite well, showing that it describes the etching effects correctly (within its limitations). In addition, the model equation derived in this work can be very useful in age correction of partially annealed glass samples.     

The relationship between the conformal and gravitational anomalies

It is shown that the vectorial part of the general coordinate transformation (GCT) anomaly cannot be eliminated by local counterterms without generating the conformal anomaly for the system with classical GCT and conformal symmetries. The vectorial part of the GCT anomaly is equivalent to the non-topological conformal anomaly similarly as the chiral part of the GCT anomaly is equivalent to the topological Lorentz anomaly. In two dimensions, the conformal anomaly is topological, and equivalent to the Lorentz anomaly up to the factor i for the left (or right) part contribution only.     

The relationship between ferritin and haemosiderin

Under conditions of iron overload haemosiderin may replace ferritin as a major iron store. Much of this haemosiderin is contained within secondary lysosomes, known as sidersomes, where it is thought to have arisen by breakdown of ferritin. We report on⁵⁷Fe Mössbauer studies of ferritin and haemosiderin prepared from iron loaded rat livers and measured over a wide temperature range. Our results indicate significantly different superparamagnetic blocking temperatures consistent with the model whereby haemosiderin is derived from ferritin by lysosomal degradation.     

Numerical investigation of relationship between water contact angle and drag reduction ratio of superhydrophobic surfaces

This paper proposes a novel bubble model to analyze drag reduction. The relationship between the slip length and air bubble height is discussed. The numerical relationship between the surface contact angle and slip length is obtained using the solid-liquid contact ratio in the Cassie equation. The surface drag reduction ratio increases by 40% at low velocities when the solid liquid contact ratio decreases from 90% to 10%. An experimental setup to study liquid/solid friction drag is reported. The drag reduction ratio for the superhydrophobic surface tested experimentally is 30%–35% at low velocities. These results are similar to the simulation results obtained at low velocities.     

The relationship between thermodynamics and the toxicity of gadolinium complexes

The suitability of gadolinium complexes as magnetic resonance imaging contrast agents depends on a number of factors. A thermodynamic relationship to toxicity exists if one assumes that the chemotoxicity of the intact complex is minimal but that the toxicity of the components of the complex (free metal and uncomplexed ligands) is substantial. Release of Gd3+ from the complex is responsible for the toxicity associated with gadolinium complexes; this release appears to be a consequence of Zn2+, Cu2+, and Ca2+ transmetallation in vivo. This hypothesis is supported by acute toxicity experiments, which demonstrate that despite a 50-fold range of LD50 values for four Gd complexes, all become lethally toxic when they release precisely the same quantity of Gd3+, and by subchronic rodent toxicity experiments, which demonstrate a set of gross and microscopic findings similar to those known to be caused by Zn2+ deficiency. Finally, this hypothesis predicts that subtle changes in formulation can further enhance the intrinsic safety of these complexes.     

The development of baryon asymmetry in the early universe

The development of an excess of baryons over antibaryons due to CP and baryon number violating reactions during the very early stages of the big bang is calculated in simple models using the Boltzmann equation. We show that it is necessary to solve the coupled Boltzmann equations in order to determine the final baryon number in any specific model.     

The temporal development of the intensity distribution in a focussed laser beam

This paper extends the steady-state calculation of the intensity distribution near the focus of a laser beam, to the case when the laser intensity is changing rapidly, over a time of order 1 picosecond. An efficient procedure for computation is outlined, allowing for the primary spherical aberration of the focussing lens and arbitrary dependence of the incident amplitude on position and time, and results are given for two trial calculations.     

The concept of energy and its early historical development

The concept of energy, the premier concept of physics and indeed of all science, is here investigated from the standpoint of its early historical origin and the philosophical implications thereof. The fundamental assumption is made that the root of the concept is the notion of invariance or constancy in the midst of change. Salient points in the development of this idea are presented from ancient times up to the publication of Lagrange'sMécanique Analytique (1788).     

An investigation of the temporal development of the pseudosparkdischarge

A study of the different discharge phases of the pseudospark discharge is presented. During the temporal development several modes of the pseudospark discharge are observed leading to a transient, high current, low pressure gas discharge with current densities of the order of 10⁴A/cm² and a forward voltage drop of about 10 ² volts. Therefore measurements of the discharge current, the total charge transported, the forward voltage drop and the influence of the gas pressure and LRC circuit, from initial phase of discharge until the transient phase to the superdense glow, are reported. Through comparison of experimental results with literature the different types of discharges are characterized. Optical studies of the radially expanding plasma column enable the temporal and spatial location of the discharge plasma. In the high current phase estimations of the temperature on the cathode surface and the solution of the Schottky-Equation show that a constriction of the ion current at microscopic surface irregularities is necessary to sustain the discharge     

The temporal development of intracavity absorption in a dye laser

Intercavity absorptions is known to lead to an enormous enhancement in the detectability of absorbing species. Here the time development of this enhancement of this enhancement is investigated in order to fix a typical time scale such measurements. This is done with a Pockles cell in front and inside a flashlamp pumped dye laser resonator. The enhancement of absorption steeply increases at laser threshold and then levels off during the letter part of the laser pulse. By Q-switching a dye laser it is demonstrated that on a time resolution of 20 nsec extinctions as low as 10^-4 can be measured with an enhancement of two orders of magnitude.     

Dual mechanisms in the perceptual processing of click train temporal regularity

Two experiments measured human sensitivity to temporal jitter in 25-click trains with inter-click intervals (ICIs) between 5 and 100 ms. In a naturalistic experiment using wideband clicks, jitter thresholds were a nonmonotonic function of ICI, peaking for ICIs near 40-60 ms. In a subsequent experiment, clicks were high-passed and presented against a low-frequency noise masker. Jitter threshold vs ICI functions lost the positive slope over short ICIs but retained the negative slope at long ICIs. The same behavior was seen in click rate discrimination tasks. Different processes mediate regularity analysis for click trains with ICIs above and below 40-60 ms.     

The relationship between formal scattering theory and the density matrix

A study has been carried out on the relationship between formal scattering theory and the density matrix formalism. The density operator is developed in terms of the scattering operator S and the observable square modulus matrix elements of S are shown to be equivalent to elements of the density matrix. The Møller wave operators are similarly treated and subsequently used in obtaining the density matrix expression for the transition matrix. Finally, using the latter, it is shown that the hierarchy of approximations to the density matrix yields equivalent results to those obtained from the Born series.     

The relationship between the canonical super-virasoro and functional super-Weyl anomalies

In this letter, recent work relating the various anomalies encountered in the different quantisation approaches, is extended to the superstring. The reparametrization and supersymmetry anomalies of the canonical approach are constructed from the super-Weyl anomaly of the path-integral approach via the descent equations. We also give an exact correspondence between this procedure and operations in canonical field theory.     

The love-hate relationship between the shell model and cluster models

We adopt a personal approach here reviewing several calculations over the years in which we have experienced confrontations between cluster models and the shell model. In previous cluster conferences, we have noted that cluster models go hand in hand with Skyrme-Hartree-Fock calculations in describing states which cannot easily, if at all, be handled by the shell model. These are the highly deformed (many particle-many hole) intruder states, linear chain states, etc. In the present work, we will consider several topics: the quadrupole moment of ⁶Li; the nonexistence of low-lying intruders in ⁸Be; and then jumping to the f _7/2 shell, we discuss the two-faceted nature of the nuclei, which sometimes display shell-model properties and other times cluster properties.