The epidemiology of Puccinia emaculata (rust) in switchgrass and evaluation of the mycoparasite Sphaerellopsis filum as a potential biological control organism for switchgrass rust.

Switchgrass (Panicum virgatum L.) is a warm-season, perennial grass, whose native range includes the entire United States and north into Canada, excluding areas along the pacific coast. Recently, symptoms and signs of rust disease (Puccinia emaculata) have been observed on agronomic switchgrass, which include chlorosis of leaf tissue, necrosis, lodging, and plant death. To evaluate disease progress of switchgrass rust, in four fields, individual leaves of twenty-five switchgrass plants were rated once per week for fifteen weeks over two growing seasons for disease severity. Rust was first observed on Julian day 166 and 152 in 2010 and 2011, respectively. Ninety-five percent of switchgrass plants were at the 5-7 leaf growth stage before rust was first observed. Disease severity progressed logistically after detection; the rate of increase in disease severity lessened in late August to early September. The log phase of disease progression occurred from mid-June to mid-August. Leaf mortality was first observed in mid-to-late June. Greater than five percent of leaf surfaces were covered with uredia by early-to-mid October. Data collected in this study indicates when rust epidemics begin and subside on switchgrass in East Tennessee. If fungicide sprays become a viable management strategy, this data will be useful in timing those applications. Growth and pycnidial production of Sphaerellopsis filum was highest on V8 juice agar, which was used to maintain cultures. To evaluate the mycoparasite’s ability to impede urediospore production and viability, uredia of P. emaculata on detached switchgrass leaves were inoculated with conidia of S. filum. Pycnidia formed in uredia at 12-14 days after inoculation. The mycoparasite significantly reduced the number of urediospores per uredium by an average of 246 spores when compared to untreated uredia. When germination of urediospores was compared between healthy or those parasitized by S. filum, percent germination was 73% and 42%, respectively. Germ tubes of urediospores from healthy uredia averaged 96.9 um in length, whereas those from parasitized uredia averaged 32.3 um at three hours. As the mycoparasite reduced urediospore production, germination, and germ tube length, further investigation into its use as a potential biological control agent for P. emaculata is warranted

Effectiveness of conservation education at the Chattanooga Zoo

Conservation is the central focus of many modern zoos and aquariums. These zoos incorporate guest education to facilitate a connection between zoo guests and animal conservation. I conducted a study at the Chattanooga Zoo and the University of Tennessee at Chattanooga which examined two modern zoo education approaches. The two approaches utilized in the study are currently used in keeper chats at the Chattanooga Zoo. The first approach is an emotional appeal (an appeal to the personalities of the chimps at the zoo) and the second approach is a utilization of a take-action initiative (recycling cell phones to reduce mining in chimpanzee habitat). Both approaches were placed at the beginning of the same chimpanzee presentation which exclusively involved facts about chimpanzees. These two approaches were tested against a control presentation that involved only the chimpanzee facts and no educational approaches. All three presentations were given to two populations, zoo guests and UTC students in front of the chimpanzee exhibit at the zoo and in various lecture halls at UTC. My goal was to examine the effects of these approaches on retention of chimpanzee related information. I hypothesized that incorporating an emotional appeal in an informational chat increases guest retention more than using a take-action initiative. The response data collected from the Chattanooga Zoo revealed no significant differences in guest retention of information between any of the three zoo chats (presentations) due to small sample size. The results from the UTC student population did yield statistically significant differences. The group exposed to the emotional appeal scored the highest on average, followed by the control group, and finally the take-action initiative group. My study may serve as a starting point for future research involving effectiveness of conservation messaging at the Chattanooga Zoo

Insights from Educational Psychology Part 4: Academic Self-Concept and Emotions

Students’ emotions are closely tied to their self-esteem, self-concept, and feelings of self-efficacy. Academic self-concept is specific to the educational context, so a student may be engaged in some academic pursuits but not connect to others. Disidentification from an academic pursuit usually causes withdrawal of effort. Anxiety is the emotion that has received the most attention from educational psychologists and librarians, but students also experience surprise, curiosity, enyoyment, confusion, frustration, and boredom. Confusion can be beneficial to learning if it is resolved before one feels overly frustrated

Insights from Educational Psychology Part 5: Learning as a Social Act

Educational psychologists have developed several theories on how individuals learn via interactions with others. Prominent ideas that apply to reference librarianship and teaching information literacy are the theory of social constructivism, social-cognitive theory, and socio-cultural theory. These theories’ emphasis on the social aspect of learning underscore why collaborative learning within diverse groups can lead to deeper and broader learning. Techniques for effectively scaffolding student learning are introduced. We highlight the key role of collaboration for students to develop the ability to transfer knowledge, and the Guided Reciprocal Peer Questioning technique for developing that ability is described

Reaction-Diffusion-Branching Models of Stock Price Fluctuations

Several models of stock trading [P. Bak et al, Physica A {\bf 246}, 430 (1997)] are analyzed in analogy with one-dimensional, two-species reaction-diffusion-branching processes. Using heuristic and scaling arguments, we show that the short-time market price variation is subdiffusive with a Hurst exponent $H=1/4$. Biased diffusion towards the market price and blind-eyed copying lead to crossovers to the empirically observed random-walk behavior ($H=1/2$) at long times. The calculated crossover forms and diffusion constants are shown to agree well with simulation data.Comment: 4 pages, 3 figure