Bumble bee parasite strains vary in resistance to phytochemicals

Nectar and pollen contain diverse phytochemicals that can reduce disease in pollinators. However, prior studies showed variable effects of nectar chemicals on infection, which could reflect variable phytochemical resistance among parasite strains. Inter-strain variation in resistance could influence evolutionary interactions between plants, pollinators, and pollinator disease, but testing direct effects of phytochemicals on parasites requires elimination of variation between bees. Using cell cultures of the bumble bee parasite Crithidia bombi, we determined (1) growth-inhibiting effects of nine floral phytochemicals and (2) variation in phytochemical resistance among four parasite strains. C. bombi growth was unaffected by naturally occurring concentrations of the known antitrypanosomal phenolics gallic acid, caffeic acid, and chlorogenic acid. However, C. bombi growth was inhibited by anabasine, eugenol, and thymol. Strains varied >3-fold in phytochemical resistance, suggesting that selection for phytochemical resistance could drive parasite evolution. Inhibitory concentrations of thymol (4.53-22.2 ppm) were similar to concentrations in Thymus vulgaris nectar (mean 5.2 ppm). Exposure of C. bombi to naturally occurring levels of phytochemicals—either within bees or during parasite transmission via flowers—could influence infection in nature. Flowers that produce antiparasitic phytochemical, including thymol, could potentially reduce infection in Bombus populations, thereby counteracting a possible contributor to pollinator decline

Seismic Failure Probability of a Curved Bridge Based on Analytical and Neural Network Approaches

This study focuses on seismic fragility assessment of horizontal curved bridge, which has been derived by neural network prediction. The objective is the optimization of structural responses of metaheuristic solutions. A regression model for the responses of the horizontal curved bridge with variable coefficients is built in the neural networks simulation environment based on the existing NTHA data. In order to achieve accurate results in a neural network, 1677 seismic analysis was performed in OpenSees. To achieve better performance of neural network and reduce the dimensionality of input data, dimensionality reduction techniques such as factor analysis approach were applied. Different types of neural network training algorithm were used and the best algorithm was adopted. The developed ANN approach is then used to verify the fragility curves of NTHA. The obtained results indicated that neural network approach could be used for predicting the seismic behavior of bridge elements and fragility, with enough feature extraction of ground motion records and response of structure according to the statistical works. Fragility curves extracted from the two approaches generally show proper compliance

A Participation Requirement to Engage Students in a Pharmacokinetics Course Synchronously Taught at a Local and Distant Campus

Objective To design, implement, and evaluate a strategy to actively engage doctor of pharmacy (PharmD) students at local and distant sites in a pharmacokinetics course. Design A Web-based system was designed that allowed second-year pharmacy students to choose whether to participate in a instructor-led class discussion session by registering prior to or during the first 10 minutes of each class. The instructor then used the program to randomly select students to respond to questions based on the assigned reading. Five percent of the overall course grade was based on class participation. Assessment For each class session, an average of 85% of students at both the local and distant campuses registered for participation in class discussion and approximately 5% were called on to respond to questions. Student responses to course survey questions regarding the participation strategy were overwhelmingly positive, with 75%-90% agreeing that the strategy more actively engaged them in classroom activities, resulting in improved learning. Student performance in all assessment categories was almost identical at the local and distant sites. Conclusions Implementation of a participation strategy in a large course synchronously taught on 2 campuses is feasible and results in successful engagement of most students at both sites