6,011 research outputs found
Developing Analytical and Communication Skills in a Mock-Trial Course Based on the Famous Woburn, Massachusetts Case
This Journal of Geoscience Education article discusses a mock trial in which undergraduates serve as expert witnesses and law students serve as their attorneys. The article identifies the trial as an effective vehicle for developing quantitative skills and enhancing written and oral communication skills. The course discussed is unabashedly about applying scientific principles to solve real-world problems. The entire course revolves around the analysis, interpretation, and presentation of scientific data. Educational levels: Graduate or professional, Undergraduate lower division, Undergraduate upper division
Birefringent filter design
A birefringent filter is provided for tuning the wavelength of a broad band emission laser. The filter comprises thin plates of a birefringent material having thicknesses which are non-unity, integral multiples of the difference between the thicknesses of the two thinnest plates. The resulting wavelength selectivity is substantially equivalent to the wavelength selectivity of a conventional filter which has a thinnest plate having a thickness equal to this thickness difference. The present invention obtains an acceptable tuning of the wavelength while avoiding a decrease in optical quality associated with conventional filters wherein the respective plate thicknesses are integral multiples of the thinnest plate
Research to determine failure modes for transistors
Failure modes of diffused planar transistors under stress screening and life testin
The Effect of a Refractory Period on the Power Spectrum of Neuronal Discharge
The interspike intervals in steady-state neuron firing are assumed to be independently and identically distributed random variables. In the simplest model discussed, each interval is assumed to be the sum of a random neuron refractory period and a statistically independent interval due to a stationary external process, whose statistics are assumed known. The power spectral density (hence the autocorrelation) of the composite neuron-firing renewal process is derived from the known spectrum of the external process and from the unknown spectrum of the neuron-refraction process. The results are applied to spike trains recorded in a previous study [2] of single neurons in the visual cortex of an awake monkey. Two models are demonstrated that may produce peaks in the power spectrum near 40 Hz
Temporal Precision of Spike Trains in Extrastriate Cortex of the Behaving Macaque Monkey
How reliably do action potentials in cortical neurons encode information about a visual stimulus? Most physiological studies do not weigh the occurrences of particular action potentials as significant but treat them only as reflections of average neuronal excitation. We report that single neurons recorded in a previous study by Newsome et al. (1989; see also Britten et al. 1992) from cortical area MT in the behaving monkey respond to dynamic and unpredictable motion stimuli with a markedly reproducible temporal modulation that is precise to a few milliseconds. This temporal modulation is stimulus dependent, being present for highly dynamic random motion but absent when the stimulus translates rigidly
Cross-Validation for Nonlinear Mixed Effects Models
Cross-validation is frequently used for model selection in a variety of
applications. However, it is difficult to apply cross-validation to mixed
effects models (including nonlinear mixed effects models or NLME models) due to
the fact that cross-validation requires "out-of-sample" predictions of the
outcome variable, which cannot be easily calculated when random effects are
present. We describe two novel variants of cross-validation that can be applied
to nonlinear mixed effects models. One variant, where out-of-sample predictions
are based on post hoc estimates of the random effects, can be used to select
the overall structural model. Another variant, where cross-validation seeks to
minimize the estimated random effects rather than the estimated residuals, can
be used to select covariates to include in the model. We show that these
methods produce accurate results in a variety of simulated data sets and apply
them to two publicly available population pharmacokinetic data sets.Comment: 38 pages, 15 figures To be published in the Journal of
Pharmacokinetics and Pharmacodynamic
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