The effects of a negative contingency between response rate and reinforcement rate on rate of responding

If the molar dependency between response rate and reinforcement rate can affect response rates, then responding should decrease when subjects are presented with a schedule which produces a negative contingency between response and reinforcement rates. Six pigeons were presented with concurrent linear variable-interval schedules with equal rates of reinforcement on the keys and where uncollected reinforcements were stored while the schedule progressed. This schedule results in a near zero correlation between response rate and reinforcement rate. During some conditions reinforcements were subtracted from the store when a fixed number of responses occurred on one of the keys, resulting in a negative correlation between response and reinforcement rates. Three variable-interval values, 30 seconds, 45 seconds, and 60 seconds, and four subtractive fixed ratio values, 5, 10, 20, and 60 were studied. An effective molar contingency should have produced a response distribution where responding was lowest on the subtractive fixed ratio component, but response rates remained equal on both keys

The N2K Consortium. I. A Hot Saturn Planet Orbiting HD 88133

The N2K ("next 2000") consortium is carrying out a distributed observing campaign with the Keck, Magellan, and Subaru telescopes, as well as the automatic photometric telescopes of Fairborn Observatory, in order to search for short-period gas giant planets around metal-rich stars. We have established a reservoir of more than 14,000 main-sequence and subgiant stars closer than 110 pc, brighter than V = 10.5, and with 0.4 0.1 dex for this survey. We outline the strategy and report the detection of a planet orbiting the metal-rich G5 IV star HD 88133 with a period of 3.41 days, semivelocity amplitude K = 35.7 m s^(-1), and M sin i = 0.29M_J. Photometric observations reveal that HD 88133 is constant on the 3.415 day radial velocity period to a limit of 0.0005 mag. Despite a transit probability of 19.5%, our photometry rules out the shallow transits predicted by the large stellar radius

Progress in Developing a New Detection Method for the Harmful Algal Bloom Species, \u3cem\u3eKarenia brevis\u3c/em\u3e, through Multiwavelength Spectroscopy

Multiwavelength spectroscopy is a rapid analytical technique that can be applied to detect, identify, and quantify microorganisms such as Karenia brevis, the species known for frequent red-tide blooms in Florida\u27s coastal waters. This research will report on a model-based interpretation of UV–vis spectra of K. brevis. The spectroscopy models are based on light scattering and absorption theories, and the approximation of the frequency-dependant optical properties of the basic constituents of living organisms. Absorption and scattering properties of K. brevis, such as cell size/shape, internal structure, and chemical composition, are shown to predict the spectral features observed in the measured spectra. The parameters for the interpretation model were based upon both reported literature values, and experimental values obtained from live cultures and pigment standards. Measured and mathematically derived spectra were compared to determine the adequacy of the model, contribute new spectral information, and to establish the proposed spectral interpretation approach as a new detection method for K. brevis

Effects of Cortisol and Lipopolysaccharide on Expression of Select Growth-, Stress- and Immune-Related Genes in Rainbow Trout Liver

Many studies have shown that stress-induced cortisol levels negatively influence growth and immunity in finfish. Despite this knowledge, few studies have assessed the direct effects of cortisol on liver immune function. Using real-time PCR, the expression of three cortisol-responsive genes (GR: glucocorticoid receptor, IGF-1: insulin-like growth factor-I and SOCS-1: suppressor of cytokine signaling-I), genes involved with innate and adaptive immunity (IL-1β: interleukin-1 beta, IgM: immunoglobin-M and Lyz: lysozyme), and liver-specific antimicrobial peptides (hepcidin and LEAP-2A: liver-expressed antimicrobial peptide-2A) was studied in vitro using rainbow trout liver slices. The abundances of GR, SOCS-1 and IGF-1 mRNAs were suppressed by cortisol treatment. Abundance of IL-1β mRNA was upregulated by LPS and suppressed by cortisol treatment in a time-dependent manner. While abundance of IgM mRNA was suppressed by cortisol treatment and stimulated by LPS, there were no effects of cortisol or LPS on abundance of Lyz mRNA. Abundance of hepcidin and LEAP-2A mRNA levels were suppressed by cortisol treatment and stimulated by LPS. These results demonstrate that cortisol directly suppresses abundance of GR, IGF-1, IL-1β, IgM, hepcidin, LEAP-2A and SOCS-1 mRNA transcripts in the rainbow trout liver. We report for the first time, a suppressive effect of cortisol (within 8 h of treatment) on hepcidin and LEAP-2A mRNAs in rainbow trout liver, which suggests that acute stress may negatively affect liver immune function in rainbow trout

Effects of cocaine on simple reaction times and sensory thresholds in baboons.

The effects of chronic, daily administration of cocaine on auditory and visual reaction times and thresholds were studied in baboons. Single intramuscular injections of cocaine hydrochloride (0.1 to 5.6 mg/kg) were given once daily for periods of 10 to 25 days, and were followed immediately by psychophysical tests designed to assess cocaine's effects on simple reaction times as on auditory and visual threshold functions. Consistent reductions in reaction times were frequently observed over the cocaine dose range of 0.32 to 1.0 mg/kg; at higher doses, either decreases or increases in reaction times were observed, depending upon the animal. Lowered reaction times generally occurred immediately following the 1st day's cocaine injection, and continued through all subsequent days during the dose administration period, suggesting little development of tolerance or sensitivity to these reaction-time effects. Reaction-time decreases showed a U-shaped dose-effect function. The greatest decreases in reaction times occurred from 0.32 to 1.0 mg/kg, and produced an average reaction-time decrease of 10 to 12%. Concurrently measured auditory and visual thresholds showed no systematic changes as a function of cocaine dose. Pausing was observed during performance of the psychophysical tasks, with the length of total session pause times being directly related to cocaine dose