The overexpectation effect (OXE) is the finding that following compound training with two asymptotic elements, X and A, animals respond less during tests of X or A alone compared to animals that did not receive such a compound treatment. During Pavlovian conditioning, the temporal relationship between a conditioned stimulus (CS) and an unconditioned stimulus (US) modulates both the nature (e.g., timing) and magnitude of the conditioned response (Catania, 1970; Roberts 1981). In three experiments, we used a conditioned magazine approach paradigm to evaluate the role of timing in the OXE. We hypothesized that the response decrement seen following overexpectation would manifest as temporally specific drops in magazine approach behavior during tests of X. In Phase 1, rats were given separate trials in which X (40 s in duration) and A (10 s in duration) signaled the arrival of a common US (e.g., sucrose). The delivery the US, moreover, occurred either 30s (Experiment 1), 15 s (Experiment 2) or 5 s (Experiment 3) after the onset of X. In Phase 2, we embedded A into X such that both elements signaled the same sucrose delivery, and consequently, the rats expected twice the sucrose. Tests of X revealed that rats responded less during the time periods in which sucrose was previously overexpected, as compared to rats that received only training trials of X alone in Phase 2 (Experiment 1 and 3) or trials with a novel element, C, embedded in X (Experiment 2). These are the first studies demonstrating a temporally specific OXE.

Channel morphologies embody the physical reaction between channel substrate, bed material, and flow regime. This study examines reach-scale morphology variability in an ungauged tropical headwater stream. Field morphology classifications are validated through quantifying instream wood distribution and modeling the down-reach hydraulic variation of boundary shear stress and mean stream power. Bifurcated reaches display increased wood abundance and loading, as they provide a means of storage for unattached pieces. This corresponds with the transition from a stepped morphology to a widened, meandering reach that bifurcates around a mid-channel bar, followed by a transition back to a stepped morphology. Hydraulic modeling of two bifurcated reaches demonstrated significant variability in shear stress and stream power in one dimension through these transitions. These results substantiate the effectiveness of coupling field classification schemes with ultra-high resolution topographic surveys when investigating unmonitored streams and they indicate that transitional reaches can punctuate bedform regularity in high-energy drainages.

The current experiments examined whether directed thinking about role models could increase students' attitudes toward pursuing math and science. Directed thinking involves persuasive strategies where individuals generate their own ideas or arguments (McGuire & McGuire, 1991). We predicted that directed thinking about role models would make role models more salient to students at the time they evaluated their attitudes toward math and science, leading to more positive attitudes (Study 1). In addition, we thought generating a few role models (as opposed to many) would be most effective (Study 2). In Study 1, some evidence supported the manipulation was effective for math attitudes, but no support was found in Study 2. We thought that students' self-generated role models may not have possessed resilience, possibly an important quality for inspiration, so we tried having students read about resilient role models (Study 3). The results of Study 3 did not support this prediction.

Past research has shown that when people describe or imagine events that did not actually occur, they can later mistakenly remember that those events did occur. These memory errors can occur even for their own actions, including past attitude reports. In addition, the more people misrepresent past actions, the greater the memory errors. The present experiments investigated two motivational factors that might cause people to differ spontaneously in the extent to which they lie about their own past attitude-relevant actions. Experiment 1 tested whether single college students would misrepresent their own previous attitude reports more to a disagreeing opposite-sex student who was single than to one who was already in a committed relationship. Experiment 2 tested whether college students would misrepresent their own previous attitude reports more to a disagreeing same-sex student who could reward them than to one who could not. Both experiments further tested whether differences in the level of misrepresentation would cause differences in what participants remembered about their own previous attitude reports. Although participants in Experiment 1 misrepresented their past attitude reports when given an opportunity to lie, the single vs. committed manipulation caused no differences in the level of misrepresentation or memory. The reward manipulation in Experiment 2 did cause differences in both the level of misrepresentation and memory. The results are discussed in terms of source monitoring framework, false memories, differences between memory and attitude processes, and self-deception.

MICROFACIES SEDIMENTOLOGY OF THE LOWER-MIDDLE KINDBLADE FORMATION (ORDOVICIAN), SLICK HILLS, SOUTHWESTERN OKLAHOMA In the late Cambrian (Franconian), a marine transgression took place on the Laurentian craton throughout a range of Cambrian rhyolite hills, and is now exposed in the Slick Hills of Southwestern Oklahoma. Evidence of the Cambro-Ordovician marine transgression is recorded in the Timbered Hills and the overlying Arbuckle Group. The Arbuckle Group is a 7, 000 ft. thick carbonate platform comprised of six formations: the Fort Sill, Signal Mountain, Mackenzie Hill, Cool Creek, Kindblade, and West Spring Creek at the top. Each formation displays diverse cyclic relationships persevered in the facies sequences and fauna. The present study examines an exposed portion of the Kindblade Formation. The exposure displays an extensive variety of microbial carbonates (stromatolites and thrombolites) as well as deep-water micritic fabrics and diagenetic features. Sediment analysis revealed the paleoenvironment as being a shallow subtidal open-marine environment with subtle cycles from storms and oscillating waves. These were differentiated by varying lithofacies associations found within thin sections and outcrop observations.

Large numbers of migratory tree-bats are being killed at wind turbines worldwide and it remains unclear why this is happening. The purpose of this study was to test the hypothesis that prey items for bats are abundant in the immediate vicinity of wind turbines. During the 2012 fall migratory season (July to October), we used light taps and malaise traps to sample the aerial invertebrate community at Wolf Ridge Wind, LLC, in north-central Texas. Overall, we collected more invertebrates and a greater number of species earlier in the season compared to later in the season and the use of malaise traps significantly added to invertebrate diversity yielded by light traps. Invertebrate abundance and species richness did not differ between the base of turbines and 400 m away, but compilation of data from previous bat diet studies suggested that the area around wind turbines provided foraging resources for local bats. Further research is needed, however, to determine if bats are attracted to wind turbines as a foraging resource.

Methyl mercury (MeHg) is one of the most hazardous contaminants in the environment, adversely affecting both human and wildlife health. Recent studies have demonstrated that aquatic insects biotransport MeHg and other contaminants to terrestrial consumers, but the factors that regulate the flux of MeHg out of aquatic ecosystems via emergent insects have not been studied. I used experimental mesocosms to test the hypothesis that insect emergence and the associated flux of MeHg from aquatic to terrestrial ecosystems is affected by both bottom-up nutrient effects and top-down fish consumer effects. Nutrient addition led to an increase in MeHg flux primarily by enhancing the biomass of emerging MeHg-contaminated insects, while fish decreased MeHg flux primarily by reducing the biomass of emerging insects. These factors were interdependent such that the nutrients effects were more pronounced when fish were absent and the fish effects were more pronounced when nutrients concentrations were high.

Bacillus anthracis must avoid an array of antibacterial defenses by the host during infection. Although anthrax toxin and capsule, located on extra-chromosomal plasmids, play important roles in the pathogenesis of this disease, evidence indicates chromosomal genes also contribute. A random chromosomal mutant library of B. anthracis Sterne was employed to identify novel chromosomal virulence factors. Mutants were screened for loss of virulence in Caenorhabditis elegans. Those unable to infect C. elegans were selected for and the site of transposon insertion was identified. The most highly attenuated mutant had a disruption in an operon containing multiple tellurium resistance genes, leading to an increased susceptibility to potassium tellurite as well as host defenses (ROS and AMPs). In addition, the mutant displays attenuated virulence in whole blood and macrophage survival in comparison to WT. We conclude the tellurium resistance operon of B. anthracis has a novel role in resistance to critical host defenses.

We recently demonstrated that ClpX is critical for the pathogenesis and resistance to cell wall-acting antimicrobials of Bacillus anthracis, the causative agent of anthrax. ClpXP is an intracellular protease conserved across many bacterial species and is often associated with cellular stresses and has been implicated in the virulence of several pathogens. Antimicrobial resistance to cell wall-acting agents can result from a decrease in autolytic activity and an increase in cell wall charge or thickness. We have examined the genetic expression of autolytic and cell charge-acting genes using real-time quantitative PCR and directly measured these characteristics in a B. anthracis mutant lacking ClpX. We examined structural cell wall differences in our ClpX mutant using scanning and transmission electron microscopy. Our results indicate that the loss of ClpX does not affect the autolytic rate or cell wall charge of B. anthracis, but does result in the thinning of the cell wall.

When does imagination shape reality? We know that the presence of others subsequently results in less helping because of diffusion of responsibility, but what effect does the imagined social context have on translating imagined helping into actual actions? People help less in actual situations, for instance, when others are present than when they are alone, but are they also less likely to help in actual situations when they have recently imagined helping with others than helping by themselves? Two studies addressed this question. Compared to those who imagined helping by themselves, participants who imagined helping with others subsequently were actually less likely to help (Study 1), whether the others were friends or strangers (Study 2).