The time course of auditory perceptual learning: neurophysiological changes during speech-sound training

Here we report that training-associated changes in neural activity can precede behavioral learning. This finding suggests that speech-sound learning occurs at a pre-attentive level which can be measured neurophysiologically (in the absence of a behavioral response) to assess the efficacy of training. Children with biologically based perceptual learning deficits as well as people who wear cochlear implants or hearing aids undergo various forms of auditory training. The effectiveness of auditory training can be difficult to assess using behavioral methods because these populations are communicatively impaired and may have attention and/or cognitive deficits. Based on our findings, if neurophysiological changes are seen during auditory training, then the training method is effectively altering the neural representation of the speech/sounds and changes in behavior are likely to follow.     

Mutation at chromosome 11q23 in human non-familial breast cancer: a microdissection microsatellite analysis

We tested the hypothesis that time series analysis can provide accurate predictions of future poison center telephone call volume by a prospective stochastic time series modeling of calls to a university-based regional poison center. All callers evaluated and managed during two sequential years had the time and date of the call recorded in a computer database. Time series variables were formed for poison center calls per hour. Prediction models were developed from the 1992 data and included four types: raw observations, moving average, means with moving average smoothing, and autoregressive integrated moving average. Forecasts from each model were tested against observations from the first 26 weeks of 1993. Each model's adequacy was tested on residuals by autocorrelation functions, integrated periodograms, linear regression, and differences among the variances. A total of 44,584 calls were received in 1992 and 24,781 in the first half of 1993. Large periodic variations in call volume with time of day were found (p < 0.001). The model based on arithmetic means of each hour of the week with three-point moving average smoothing yielded the most accurate forecasts and explained 58.5% of the variation observed in the 1993 test series (p < 0.001). Time series analysis can provide powerful, accurate short range forecasts of future poison center telephone call volume. Simpler, less expensive models performed best in this study.     

Power losses in steel pipe delivering very large currents

This paper presents a finite difference time domain solution for the electromagnetic fields in ferromagnetic conducting steel pipes of the type used to deliver large currents for in situ heating of heavy oil reservoirs and for in situ environmental decontamination. A method is described whereby a single measured hysteresis loop can be used to deduce the family of hysteresis loops that governs the variable magnetic behavior throughout the pipe wall. Hysteresis and eddy current losses are calculated, and it is shown that hysteresis effects greatly alter the eddy current distribution and can more than triple the total power losses in the steel pipe when compared to the power losses that would be present if hysteresis effects are ignored and magnetic permeability is assumed constant     

Novel calcium phosphate composite bone cement: strength and bonding properties

A new high-strength cement prepared from calcium phosphate and calcium aluminate has been developed and was evaluated for potential use in bone and joint repair applications. Cement specimens were aged under simulated physiological conditions. The compressive strength of the cement was determined at time intervals 1 h after setting up to 52 weeks. A compressive strength of 111.6±12.9 MPa was measured at 4 weeks, with the cement attaining 64% of this maximum strength within 4 h of preparation. Compressive strength greater than 90 MPa was maintained up to 52 weeks. The strength of the cement–prosthesis interface was studied using a pull-out test. Polished, 316L stainless steel rods were implanted in canine cadaver femurs to simulate a cemented hip prosthesis. At 4, 24 h, and 60 days post implantation, the force required to displace the rod was measured. Mean interfacial shear strengths of 1.17±0.25, 1.11±0.21, and 1.11±0.32 MPa were observed at respective time-periods.     

Load bearing characteristics of ceramic refractories

This paper describes the underlying mechanisms of deformation of refractories at high temperatures. Equations for deformation by consolidation of pores and by slumping are developed.In this paper, the heavy refractories are shown to deform primarily by viscous flow. The hot load behavior of a fireclay at 1450°C. was analyzed and found to be predominantly compaction of pores by the Mackenzie-Shuttleworth viscous flow mechanism with an activation energy of 100 Kcal/mol.     

Automatic Power Control for Electric-Arc Furnaces

By using a predetermined optimum power input program, the efficiency of electric-arc furnaces can be improved. The equipment, reasoning, and results of furnace tests for increasing efficiencies are described.     

Routine postpartum treatment of dairy cattle with intrauterine neomycin sulfate boluses.

Within location, 119 dairy cattle from two experiment station herds, which had no problems associated with parturition, were randomly either treated by insertion of two intrauterine boluses containing a total of 1000 mg neomycin sulfate 24 h postpartum or maintained as a control. Uteri and ovaries of all cows were palpated 17 to 24 days postpartum and at 14 day intervals thereafter until inovulation of the uterus was judged complete and an estrus had been observed. All cows were inseminated at the first estrus after 60 days postpartum and at each estrus thereafter until conception. Cows treated with neomycin sulfate required more services per conception (1.7 to 1.4) and were open more days before conception (100.5 to 88.5) than the controls. The probable cause of the lowered reproductive efficiency is discussed. Treatment did not later significantly days to ovulation, estrus, involution, or first service. Three treated and five control animals needed additional uterine treatment. Routine intrauterine treatment of all cows with neomycin sulfate boluses should not be recommended.     

On the mechanism of the N(4S) + CS2reactions: N2-CO2laser pumping from the products of the N(4S) + CS2reaction

The reaction of N atoms with CS2has been studied and a mechanism for the reaction proposed. It has been demonstrated that the N + NS reaction produces vibrationally excited N2. Evidence has been presented which indicates that the rate of the N + CS2reaction is substantially slower than first indicated. The analogous reaction N + OCS → NS + CO has also been studied and a mechanism proposed.     

Microstructure and elastic properties of sintered hydroxyapatite

The paper focuses on the dependence of microstructure and elastic properties of sintered hydroxyapatite on the processing parameters. Several specimens were sintered in conventional furnace at various temperatures. Elastic moduli were measured ultrasonically and information about the microstructure was recovered from these data and then verified by analysis of microphotographs. It was obtained that the average shape of pores becomes more round as the sintering temperature increases. That leads, in particular, to higher fracture toughness of the material since the stress concentration near pores is reduced.