Continuous time vertex-reinforced jump processes

 We study the continuous time integer valued process , which jumps to each of its two nearest neighbors at the rate of one plus the total time the process has previously spent at that neighbor. We show that the proportion of the time before t which this process spends at integers j converges to positive random variables V _j , which sum to one, and whose joint distribution is explicitly described. We also show Received: 19 December 2000 / Revised version: 1 November 2001 / Published online: 17 May 2002     

Initial state and transition state solvation effects in the cobaltitungstate oxidation of iodide in binary aqueous solvent mixtures

Summary Rate constants are reported for 12-tungstocobaltate(III) [CoW₁₂O₄₀]^5– oxidation of iodide in water and in binary aqueous solvent mixtures containing up to 40% methanol, 40% acetonitrile, or 60% dimethyl sulphoxide. From these kinetic results, solubility measurements on potassium 12-tungstocobaltate(III), and published data on Gibbs free energies of transfer of appropriate ions, it has been deduced that the dominant factor in determining the marked decrease in rate observed on going from water into the binary aqueous solvent mixtures is destabilisation of the transition state for the electron-transfer reaction.     

Kinetic and spectroscopic studies of an intermediate in the reaction of the diimine complex trisferrozineiron(II) with hydroxide ion in water and in aqueous methanol

Summary Kinetic and spectroscopic evidence is presented to support the postulate of a ligand-substituted intermediate in the reaction of the trisferrozineiron(II) anion with hydroxide ion in water and in aqueous methanol.     

Measurement of traffic noise shielding provided by buildings

This paper presents a comparison between some current prediction methods for traffic noise shielding provided by buildings and the actual measured attenuations in typical residential areas. Generally, it was found that the method developed by the Department of Environment in the UK gives a reasonably accurate prediction of attenuation by shielding in fairly simple situations. In more complex situations, and particularly where a receiving position is close to a significant shielding structure, such as building, the attenuation obtained is underpredicted by the DOE method, thus the design facade levels for the rear of a building are overpredicted; however, in some other situations, the DOE method overpredicts the attenuation obtained. The attenuations measured for individual noise events under nominally identical conditions are shown to have large variations in attenuation.     

Heritability of Stroop and flanker performance in 12-year old children

Background  

There is great interest in appropriate phenotypes that serve as indicator of genetically transmitted frontal (dys)function, such as ADHD. Here we investigate the ability to deal with response conflict, and we ask to what extent performance variation on response interference tasks is caused by genetic variation. We tested a large sample of 12-year old monozygotic and dizygotic twins on two well-known and closely related response interference tasks; the color Stroop task and the Eriksen flanker task. Using structural equation modelling we assessed the heritability of several performance indices derived from those tasks.     

Accurate analysis of multitone signals using a DFT

Optimum data windows make it possible to determine accurately the amplitude, phase, and frequency of one or more tones (sinusoidal components) in a signal. Procedures presented in this paper can be applied to noisy signals, signals having moderate nonstationarity, and tones close in frequency. They are relevant to many areas of acoustics where sounds are quasistationary. Among these are acoustic probes transmitted through media and natural sounds, such as animal vocalization, speech, and music. The paper includes criteria for multitone FFT block design and an example of application to sound transmission in the atmosphere.     

Instantaneous, stoichiometric generation of powerfully reducing states of protein active sites using Eu(II) and polyaminocarboxylate ligands

Addition of an equivalent of a polyaminocarboxylate ligand (L) to a solution of a redox protein and the aqua Eu2+ ion results in the instantaneous in situ generation of a very powerful reductant Eu(II)-L that can rapidly drive an electron stoichiometrically onto a redox centre having an extremely negative reduction potential (lower than -1 V): this is exemplified by straightforward generation of the super-reduced state of the Fe-protein of nitrogenase.     

The contribution of high frequencies to human brain activity underlying horizontal localization of natural spatial sounds

Background  

In the field of auditory neuroscience, much research has focused on the neural processes underlying human sound localization. A recent magnetoencephalography (MEG) study investigated localization-related brain activity by measuring the N1m event-related response originating in the auditory cortex. It was found that the dynamic range of the right-hemispheric N1m response, defined as the mean difference in response magnitude between contralateral and ipsilateral stimulation, reflects cortical activity related to the discrimination of horizontal sound direction. Interestingly, the results also suggested that the presence of realistic spectral information within horizontally located spatial sounds resulted in a larger right-hemispheric N1m dynamic range. Spectral cues being predominant at high frequencies, the present study further investigated the issue by removing frequencies from the spatial stimuli with low-pass filtering. This resulted in a stepwise elimination of direction-specific spectral information. Interaural time and level differences were kept constant. The original, unfiltered stimuli were broadband noise signals presented from five frontal horizontal directions and binaurally recorded for eight human subjects with miniature microphones placed in each subject's ear canals. Stimuli were presented to the subjects during MEG registration and in a behavioral listening experiment.