Biology and Control of Rice False Smut Caused by Ustilaginoidea virens (Teleomorph Villosiclava virens)

Rice false smut (FS), a disease caused by Ustilaginoidea virens (Cke.) Takahashi (1896), was first reported in northeastern Arkansas counties in 1997. The first objective of this research was to establish a collection of U. virens isolates from geographically diverse regions of Arkansas. Three U. virens isolates and chlamydospores from `Templeton\u27 and `Clearfield-151\u27 rice cultivars were used to determine the effects of temperature and pH on mycelial growth and germination. A nested-PCR protocol and histological methods were used to determine if U. virens infects and colonizes rice seedlings and spikelets on panicles. The sensitivity of three U. virens isolates was tested to analyze the inhibition of mycelial growth in vitro and to establish inhibitory concentrations to six technical and five analytical grade fungicides. Field and greenhouse tests were conducted to determine if fungicide seed treatments using technical grade fungicides could effectively reduce the incidence of U. virens rDNA in seedlings as measured by nested-PCR. Finally, field tests were conducted using fungicide seed treatments to control FS at two locations and disease was assessed by a visual disease assessment. We have an established collection of 190 isolates obtained from nine cultivars in seven counties of Arkansas, USA. Mycelial growth and germination of chlamydospores occurred between pH levels from 5.5 to 8.0. Mycelial growth and germination of chlamydospores occurred at temperatures from 18° to 34°C and from 18 to 26°C, respectively. Nested-PCR tests indicate the protocol is specific and sensitive for detecting U. virens in rice. Ribosomal DNA of U. virens was detected using nested-PCR from seedlings within three days after emergence from the soil and in 27.5 to 75% of spikelets in booted panicles before exsertion. Selected isolates of U. virens were sensitive to fungicides in-vitro but results from using nested-PCR in the greenhouse and field to screen seedlings for U. virens rDNA indicated a significant reduction in the incidence of U. virens in some seed treatments compared to controls. Seed treatments did not significantly reduce FS disease compared to controls in the field plots when measured by visual disease assessments

Writing the revolution: radicalism and the U.S. historical romance, 1835-1860

This dissertation examines popular fictions that employed the history and iconography of the American Revolution to promote radical reform movements in the antebellum United States. The project challenges common critical assumptions that historical fictions—and particularly those drawing upon Revolutionary history—are inherently nostalgic and capable of conveying only a limited range of political meanings. Rather than conservative efforts to preserve Revolutionary history, many works of this type were extensions of their authors’ progressive reform efforts. These historical fictions sought to recruit readers to the cause of completing the democratizing work of the Revolution in order to ensure that the people maintained control over their own institutions. The project considers works by authors who circulated among groups and parties that contributed to the democratic tumult of the antebellum period, including Catharine Maria Sedgwick, George Lippard, Herman Melville, Frederick Douglass, and Harriet Beecher Stowe. As members—either centrally or peripherally—of opposition political parties, unions, and reform groups, these authors spoke on behalf of, or were received as engaging with, campaigns for labor reform, socialism, and abolitionism. Situating these texts within contemporary radical reform movements reveals that they explicitly endorsed policies such as labor reform, socialism, or abolitionism. Even texts by supposedly moderate writers provoked enthusiastic responses from radicals—and chagrin or outrage from conservatives. Reading these texts in light of the controversies and contestations that permeated antebellum culture enables us to recover their radical potential. By re-imagining the past, authors infused their version of Revolutionary history with their own political concerns. This project uncovers within this supposedly conservative genre calls for pension reform for veterans, democratized suffrage, debt relief measures, the formation of unions and socialist cooperatives, and the abolition of slavery. It concludes by examining the dissolution or breakdown of the genre as America neared Civil War and it became increasingly evident that violence, rather than print culture, would be necessary to resolve the nation’s divisions

Counterfactual Evaluation of Peer-Review Assignment Policies

Peer review assignment algorithms aim to match research papers to suitable expert reviewers, working to maximize the quality of the resulting reviews. A key challenge in designing effective assignment policies is evaluating how changes to the assignment algorithm map to changes in review quality. In this work, we leverage recently proposed policies that introduce randomness in peer-review assignment--in order to mitigate fraud--as a valuable opportunity to evaluate counterfactual assignment policies. Specifically, we exploit how such randomized assignments provide a positive probability of observing the reviews of many assignment policies of interest. To address challenges in applying standard off-policy evaluation methods, such as violations of positivity, we introduce novel methods for partial identification based on monotonicity and Lipschitz smoothness assumptions for the mapping between reviewer-paper covariates and outcomes. We apply our methods to peer-review data from two computer science venues: the TPDP'21 workshop (95 papers and 35 reviewers) and the AAAI'22 conference (8,450 papers and 3,145 reviewers). We consider estimates of (i) the effect on review quality when changing weights in the assignment algorithm, e.g., weighting reviewers' bids vs. textual similarity (between the review's past papers and the submission), and (ii) the "cost of randomization", capturing the difference in expected quality between the perturbed and unperturbed optimal match. We find that placing higher weight on text similarity results in higher review quality and that introducing randomization in the reviewer-paper assignment only marginally reduces the review quality. Our methods for partial identification may be of independent interest, while our off-policy approach can likely find use evaluating a broad class of algorithmic matching systems

Bounding regret in empirical games

Empirical game-theoretic analysis refers to a set of models and techniques for solving large-scale games. However, there is a lack of a quantitative guarantee about the quality of output approximate Nash equilibria (NE). A natural quantitative guarantee for such an approximate NE is the regret in the game (i.e. the best deviation gain). We formulate this deviation gain computation as a multi-armed bandit problem, with a new optimization goal unlike those studied in prior work. We propose an efficient algorithm Super-Arm UCB (SAUCB) for the problem and a number of variants. We present sample complexity results as well as extensive experiments that show the better performance of SAUCB compared to several baselines

A One-Size-Fits-All Approach to Improving Randomness in Paper Assignment

The assignment of papers to reviewers is a crucial part of the peer review processes of large publication venues, where organizers (e.g., conference program chairs) rely on algorithms to perform automated paper assignment. As such, a major challenge for the organizers of these processes is to specify paper assignment algorithms that find appropriate assignments with respect to various desiderata. Although the main objective when choosing a good paper assignment is to maximize the expertise of each reviewer for their assigned papers, several other considerations make introducing randomization into the paper assignment desirable: robustness to malicious behavior, the ability to evaluate alternative paper assignments, reviewer diversity, and reviewer anonymity. However, it is unclear in what way one should randomize the paper assignment in order to best satisfy all of these considerations simultaneously. In this work, we present a practical, one-size-fits-all method for randomized paper assignment intended to perform well across different motivations for randomness. We show theoretically and experimentally that our method outperforms currently-deployed methods for randomized paper assignment on several intuitive randomness metrics, demonstrating that the randomized assignments produced by our method are general-purpose.Comment: 24 pages, 8 figures, 3 tables, neurips 2023 spotligh

A Dataset on Malicious Paper Bidding in Peer Review

In conference peer review, reviewers are often asked to provide "bids" on each submitted paper that express their interest in reviewing that paper. A paper assignment algorithm then uses these bids (along with other data) to compute a high-quality assignment of reviewers to papers. However, this process has been exploited by malicious reviewers who strategically bid in order to unethically manipulate the paper assignment, crucially undermining the peer review process. For example, these reviewers may aim to get assigned to a friend's paper as part of a quid-pro-quo deal. A critical impediment towards creating and evaluating methods to mitigate this issue is the lack of any publicly-available data on malicious paper bidding. In this work, we collect and publicly release a novel dataset to fill this gap, collected from a mock conference activity where participants were instructed to bid either honestly or maliciously. We further provide a descriptive analysis of the bidding behavior, including our categorization of different strategies employed by participants. Finally, we evaluate the ability of each strategy to manipulate the assignment, and also evaluate the performance of some simple algorithms meant to detect malicious bidding. The performance of these detection algorithms can be taken as a baseline for future research on detecting malicious bidding

Evaluation of harvest time/temperature and storage temperature on postharvest incidence of red drupelet reversion development and firmness of blackberry (Rubus L. subgenus Rubus Watson)

Since 1964, the University of Arkansas blackberry breeding program has worked to improve fruit quality and shipping capabilities. A major limitation in blackberry fruit is postharvest handling potential for the shipping market. Maintaining fruit firmness in storage is crucial. Red drupelet reversion (or simply reversion) is also an important postharvest disorder in which drupelets change from black to red during storage. It is hypothesized that reversion is increased when fruit is picked at hot temperatures and exposed to a rapid change of temperature. These studies evaluated harvest time/temperature, as well as storage temperature, on berry firmness and the incidence of reversion. In Study One, eight genotypes were evaluated. Fruit was harvested at four harvest times (7:00 AM, 10:00 AM, 1:00 PM and 4:00 PM) and then stored for 7 d at 5 °C before evaluation. Results indicated significant sources of variation were genotype and time of harvest for the variables compression (a measure of firmness) and incidence of reversion. Breeding selection A-2453T maintained high firmness and low incidence of reversion after storage compared to other genotypes. Reversion was also significantly lower at the 7:00 AM harvest time compared to later harvests. Study Two included two genotypes harvested at 7:00 AM and 1:00 PM which were evaluated at different storage temperatures (5 and 1 °C). No significant effects were found; however, trends suggested that A-2453T maintained higher firmness despite storage temperature. These studies confirm differences in firmness and reversion among genotypes as well as reveal harvest time impact on reversion

BLUE LIGHT THERAPY INDUCES A DECREASE IN THE FUNCTIONAL BRAIN RESPONSE TO SUBLIMINAL PRESENTATION OF SOCIAL THREAT IN POST-TRAUMATIC STRESS DISORDER

The exact mechanisms by which sleep, fear conditioning, emotional processing, and psychopathology all interact in the context of Post-Traumatic Stress Disorder (PTSD) during the weeks, months, and years post-trauma is a relatively novel field of research, and a standard treatment method for PTSD unfortunately remains underdeveloped. This study’s goal was to investigate the overall usefulness of Blue Light Therapy (BLT) as a non-pharmacologic approach to treating symptoms of PTSD specifically, and improving emotional processing, as measured by the Masked Affect Task (MAT). It was proposed that six weeks of BLT compared to an amber light placebo would result in a marked reduction in left amygdala response to fearful facial stimuli, as well as an increased activation of the ventromedial prefrontal cortex (vmPFC). Participants diagnosed with PTSD underwent two visits during which they were asked to complete questionnaires, undergo a fear-conditioning task, and complete certain tasks and resting state measures in a functional magnetic resonance imaging (fMRI) scanner. These two visits were separated by six weeks of daily 30-minute light treatment with either blue light or amber light placebo and completion of self-report sleep diaries. Though participants in both conditions showed a decrease in PTSD severity, results were not indicative of a statistically significant reduction of activity in the left amygdala or an increase in the ventromedial prefrontal cortex (vmPFC). However, a significant decrease in activity in the anterior insula in response to fearful facial stimuli was shown after six weeks of BLT compared to the placebo amber light group. These results enhance our understanding of theneural mechanisms by which this decrease in fear neurocircuitry activation takes place following blue light exposure. These findings have the potential to inform future therapeutic approaches to the treatment of PTSD, as BLT is a simple adjunctive method for existing therapeutic practices

Nature, depression, and the vagus nerve

honors thesisCollege of HumanitiesInternational StudiesDave StrayerThe positive effects of natural environments on mental health have been observed and studied for decades. Specifically, psychology research from across the world has provided evidence that being immersed in nature has positive effects for those suffering from depression, although there is uncertainty about the mechanisms behind this relationship. Scott et al. (2021) proposed that cognitive restoration and stress recovery in nature are indications of stimulation of the vagus nerve. Applying Scott et al.'s (2021) argument to research on nature and depression, this paper argues that activation of the vagus nerve is part of the mechanism by which nature exposure decreases depression. Research on the direct relationship between being in nature and vagal tone in individuals with depression is needed in order to determine if this relationship exists. In an increasingly globalized world, it is vital that this research includes participants and researchers who are from different cultural backgrounds in order to determine that this interaction is present across humans from diverse backgrounds and what socio-cultural influences are not understood currently. Further, this research can not only be applied in the mental health field, but it can also be used in environmental advocacy