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Stable isotopes are a powerful tool for ecologists, often used to assess contributions of different sources to a mixture (e.g. prey to a consumer). Mixing models use stable isotope data to estimate the contribution of sources to a mixture. Uncertainty associated with mixing models is often substantial, but has not yet been fully incorporated in models. We(More)
Rabbits received 0 to 450 exposures of a tone conditioned stimulus (CS) prior to classical defensive conditioning of the nicitating membrane response based on an infraorbital eye shock unconditioned stimulus. Tone preexposure resulted in retarded conditioning in normal rabbits. This latent inhibition effect was not present in animals with bilateral dorsal(More)
Cells progressing through the cell cycle must commit irreversibly to mitosis without slipping back to interphase before properly segregating their chromosomes. A mathematical model of cell-cycle progression in cell-free egg extracts from frog predicts that irreversible transitions into and out of mitosis are driven by hysteresis in the molecular control(More)
A previously described neural-network model (Desmond 1991; Desmond and Moore 1988; Moore et al. 1989) predicts that both CS-onset-evoked and CS-offset-evoked stimulus trace processes acquire associative strength during classical conditioning, and that CR waveforms can be altered by manipulating the time at which the processes are activated. In a trace(More)
The activity of neurons in the interposed and dentate nuclei of the cerebellum was investigated during differential classical conditioning of the rabbit eye blink nictitating membrane response. Forty-seven percent of the 165 cells in the study responded to the orbital stimulation used as the unconditioned stimulus (US). The latency distribution of(More)
A neuron-like adaptive element with computational features suitable for classical conditioning, the Sutton-Barto (S-B) model, was extended to simulate real-time aspects of the conditioned nictitating membrane (NM) response. The aspects of concern were response topography, CR-related neuronal firing, and interstimulus interval (ISI) effects for forward-delay(More)
Previous investigations have suggested that the cerebellum and associated brainstem structures, including the red nucleus, are essential for the expression of the classically conditioned nictitating membrane (NM) response. The present study examined the firing patterns of extracellularly-recorded single units in the red nucleus of the awake rabbit during(More)
Conditioned eyeblink responses are presumably learned in the cerebellum and relayed to motoneurons by way of the red nucleus. Projections from the red nucleus to cerebellar cortex (Larsell's lobule HVI) could be important for shaping temporally adaptive features of the conditioned response. Rabbits that had pipettes containing wheat germ agglutinated(More)
The associations between serum concentrations of oestradiol, testosterone and sex hormone-binding globulin (SHBG) and risk of breast cancer in post-menopausal women were investigated in a prospective study on the island of Guernsey. Sixty-one women who developed breast cancer an average of 7.8 years after blood collection were matched for age, year of blood(More)