A Study of the Thallium Dithizone Complex Using Radioactive Tracer Techniques

In the present work, use has been made of a radioactive isotope of thallium as a tracer in the study of the thallium dithizone complex

The Penguin: a Low Reynolds Number Powered Glider for Station Keeping Missions

The Penguin is a low Reynolds number (approx. 100,000) remotely piloted vehicle (RPV). It was designed to fly three laps indoors around two pylons in a figure-eight course while maximizing loiter time. The Penguin's low Reynolds number mission is an important one currently being studied for possible future flights in the atmospheres of other planets and for specialized military missions. Although the Penguin's mission seemed quite simple at first, the challenges of such low Reynolds number flight have proven to be quite unique. In addition to the constraint of low Reynolds number flight, the aircraft had to be robust in its control, highly durable, and it had to carry a small instrument package. The Penguin's flight plan, concept, performance, aerodynamic design, weight estimation, structural design, propulsion, stability and control, and cost estimate is detailed

Lepidopteran Granivory Reduces Seed Counts in a Rare Species of Riparian Scour Prairies

In Pennsylvania Baptisia australis var. australis is found along only four waterways: the Allegheny River, Youghiogheny River, Clarion River, and Red Bank Creek. Because of its limited distribution and small number of extant populations, the species is considered state-threatened in Pennsylvania. In addition, the riparian prairie habitat that Pennsylvania Baptisia australis var. australis is restricted to is also in decline and considered vulnerable. Because of these conservation concerns, insights into the natural history of the taxon in the state is valuable and will inform conservation efforts. Field surveys and fruit collections along the Allegheny River and herbarium collections were used to investigate and document granivory in Pennsylvania Baptisia australis var. australis, a phenomenon recorded in other parts of the species\u27 range, but not previously reported on in Pennsylvania. Using a model of best fit, the number of seeds found in fruit was found to be significantly impacted by the presence of granivores. We also report that visual surveys of fruits in the field are found to be accurate assessments of the presence and potential impact of granivores. In turn, our results will inform the conservation and management of Baptisia australis var. australis populations in Pennsylvania and highlight the importance of field surveys in protecting threatened taxa

To Approach or Avoid: An Introductory Overview of the Study of Anxiety Using Rodent Assays

Anxiety is a widely studied phenomenon in behavioral neuroscience, but the recent literature lacks an overview of the major conceptual framework underlying anxiety research to introduce young researchers to the field. In this mini-review article, which is aimed toward new undergraduate and graduate students, we discuss how researchers exploit the approach-avoidance conflict, an internal conflict rodents face between exploration of novel environments and avoidance of danger, to inform rodent assays that allow for the measurement of anxiety-related behavior in the laboratory. We review five widely-used rodent anxiety assays, consider the pharmacological validity of these assays, and discuss neural circuits that have recently been shown to modulate anxiety using the assays described. Finally, we offer related lines of inquiry and comment on potential future directions

Factors that Influence Teachers’ Views on Standardized Tests

The central aim of this study was to explore K-12 teachers’ (N = 183) attitudes about standardized tests as a function of experience, instructional level, student population, and type of school. The Teachers’ Views on Standardized Tests Questionnaire was developed to assess teachers’ perceptions of the impact of standardized tests on practice. All survey items were intended to measure a facet of teachers’ attitudes regarding the necessity of standardized tests and their influence on best practices. Findings from this study indicated that special education and inclusion teachers viewed standardized tests as more negatively influencing instruction than general education teachers. There were also significant differences by instructional level and type of school (i.e., public vs. independent). Compared to elementary teachers, middle and high school teachers’ views were more negative, and public school educators perceived standardized assessments as having a more negative influence on instruction than teachers in independent schools. Finally, elementary school teachers reported that the standards of learning were more appropriate in contrast to middle and high school teachers

Characterization of ventromedial hypothalamus activity during exposure to innate and conditioned threats

In the face of imminent predatory danger, animals quickly detect the threat and mobilize key survival defensive actions, such as escape and freezing. The dorsomedial portion of the ventromedial hypothalamus (VMH) is a central node in innate and conditioned predator-induced defensive behaviours. Prior studies have shown that activity of steroidogenic factor 1 (sf1)-expressing VMH cells is necessary for such defensive behaviours. However, sf1-VMH neural activity during exposure to predatory threats has not been well characterized. Here, we use single-cell recordings of calcium transients from VMH cells in male and female mice. We show this region is activated by threat proximity and that it encodes future occurrence of escape but not freezing. Our data also show that VMH cells encoded proximity of an innate predatory threat but not a fear-conditioned shock grid. Furthermore, chemogenetic activation of the VMH increases avoidance of innate threats, such as open spaces and a live predator. This manipulation also increased freezing towards the predator, without altering defensive behaviours induced by a shock grid. Lastly, we show that optogenetic VMH activation recruited a broad swath of regions, suggestive of widespread changes in neural defensive state. Taken together, these data reveal the neural dynamics of the VMH during predator exposure and further highlight its role as a critical component of the hypothalamic predator defense system