Methods of Smile: A Science Seminar Course in Deliberate Education

Oregon State University’s Science and Math Investigative Learning Experiences (SMILE) Program is an enrichment program for minority and underrepresented K-12 students. Through an eight-year iterative process, SMILE has developed and refined a science seminar course that allows undergraduate and master’s degree students to explore science enrichment for youth. Students enrolled in the course are engaged in teaching and learning as a community of learners with a focus on service learning. The intended audience for the course is those students who are interested in working in educational settings with youth—as classroom teachers, science/mathematics professionals engaged in precollege outreach, and the like. The actual audience, though quite broad, represents those students who want to be better prepared as effective science educators in their various career roles. This article provides the context for the course, defines and examines deliberate education as illustrated by the structure and activities of the Methods of SMILE seminar course, highlights the elements of an effective community of learners as demonstrated through it, details the specific strategies and activities of it, and summarizes the next steps in identifying its impact in transforming the participants’ college experiences

Spray Characterization and Herbicide Efficacy as Influenced by Pulse-Width Modulation Sprayers

Pesticide applications are a heavily scrutinized facet of today’s agricultural industry, and a concerted effort to optimize each application needs to be implemented. More precise and efficient pesticide applications are necessary to meet regulatory demands and increase economic efficiency through reduced pesticide inputs. Current pesticide application methods using precision technologies, including pulse-width modulation (PWM) sprayers, can assist with these goals. However, vast advancements in pesticide formulations, adjuvants, and nozzles, as well as the increasing popularity of PWM systems, have only increased the need for applied PWM and weed science research. Additionally, efforts have been placed on increasing spray droplet size to reduce particle drift, but this practice has led to reduced herbicide efficacy. Therefore, identifying an optimum herbicide droplet size which can reduce particle drift while simultaneously maintaining efficacy is a necessity. The objectives of this research were to: (1) identify the influence of application parameters on droplet size, droplet exit velocity, nozzle tip pressure, and spray pattern uniformity from a PWM sprayer, (2) create best use PWM recommendations to optimize pesticide applications from these sprayers, (3) investigate the effect of spray droplet size and carrier volume on the efficacy of multiple herbicide solutions, (4) establish novel weed management recommendations based on an optimum droplet size, and (5) determine the plausibility of using PWM sprayers in site-specific weed management strategies. The results of this research have led to more precise PWM sprayer operation through clear and concise best use recommendations. The capability of PWM sprayers to make precise and uniform applications can assist with the reduction of spray particle drift and increase the overall application effectiveness. Additionally, site-specific weed management strategies were effectively established and optimum herbicide droplet sizes were estimated across a wide range of geographies and weed species. Although, convoluted interactions were identified between droplet size, carrier volume, and other application parameters in regards to their effect on herbicide efficacy. As a result of this research, applicators can more effectively utilize PWM sprayers, reduce herbicide inputs, mitigate spray particle drift, and reduce the selection pressure for the evolution of herbicide-resistant weeds. Advisor: Greg R. Kruge

Cure Violence: A Public Health Model to Reduce Gun Violence

Scholars and practitioners alike in recent years have suggested that real and lasting progress in the fight against gun violence requires changing the social norms and attitudes that perpetuate violence and the use of guns. The Cure Violence model is a public health approach to gun violence reduction that seeks to change individual and community attitudes and norms about gun violence. It considers gun violence to be analogous to a communicable disease that passes from person to person when left untreated. Cure Violence operates independently of, while hopefully not undermining, law enforcement. In this article, we describe the theoretical basis for the program, review existing program evaluations, identify several challenges facing evaluators, and offer directions for future research

A statnet Tutorial

The statnet suite of R packages contains a wide range of functionality for the statistical analysis of social networks, including the implementation of exponential-family random graph (ERG) models. In this paper we illustrate some of the functionality of statnet through a tutorial analysis of a friendship network of 1,461 adolescents.

ergm: A Package to Fit, Simulate and Diagnose Exponential-Family Models for Networks

We describe some of the capabilities of the ergm package and the statistical theory underlying it. This package contains tools for accomplishing three important, and inter-related, tasks involving exponential-family random graph models (ERGMs): estimation, simulation, and goodness of fit. More precisely, ergm has the capability of approximating a maximum likelihood estimator for an ERGM given a network data set; simulating new network data sets from a fitted ERGM using Markov chain Monte Carlo; and assessing how well a fitted ERGM does at capturing characteristics of a particular network data set.

Droplet size and nozzle tip pressure from a pulse-width modulation sprayer

Pulse-width modulation (PWM) sprayers can improve application accuracy through flow control, turn compensation, and high-resolution overlap control by pulsing an electronically-actuated solenoid valve which controls the relative proportion of time each solenoid valve is open (duty cycle). The objective of this experiment was to identify the droplet size distribution and nozzle tip pressure when influenced by PWM duty cycle, nozzle technology, and gauge pressure to provide PWM guidelines. The experiment was conducted in a low-speed wind tunnel at the Pesticide Application Technology Laboratory using a SharpShooter® PWM system. In general, for non-venturi nozzles, as duty cycle decreased, droplet size slightly increased between 40 and 100% duty cycles. Conversely, venturi nozzles did not always follow this trend. The lowest duty cycle evaluated (20%) negatively impacted droplet size and caused inconsistencies for all nozzle by pressure combinations. The addition of a solenoid valve lowered nozzle tip pressure while gauge pressure remained constant indicating a restriction is present within the solenoid valve. Greater orifice sizes increased the pressure loss observed. Duty cycle minimally impacted nozzle tip pressure trends which were similar to the electrical square wave PWM signals. However, venturi nozzles deviated from this trend, specifically twin-fan, single pre-orifice venturi nozzles. In conclusion, venturi nozzles are not recommended for PWM systems as they may lead to inconsistent applications, specifically in regards to droplet size generation and nozzle tip pressures. Spray pressures of 276 kPa or greater and PWM duty cycles of 40% or greater are recommended to ensure proper PWM operation

statnet: Software Tools for the Representation, Visualization, Analysis and Simulation of Network Data

statnet is a suite of software packages for statistical network analysis. The packages implement recent advances in network modeling based on exponential-family random graph models (ERGM). The components of the package provide a comprehensive framework for ERGM-based network modeling, including tools for model estimation, model evaluation, model-based network simulation, and network visualization. This broad functionality is powered by a central Markov chain Monte Carlo (MCMC) algorithm. The coding is optimized for speed and robustness.

Rock Response in a 12-M Tunnel through a Zone of Low Strength

At the Rocky Mountain Pumped Storage Project a 12 meter diameter power tunnel was excavated through sedimentary rock for 760 meters. Approximately 10% of this tunnel was through Pennington shale that is described as a dark gray massive organic shale. This paper will describe the methods of testing .and rock characterization, the results of instrumentation and monitoring, and the post-construction testing program for the excavation, and conclude with a discussion of the observed rock response in relation to the measured strength and deformation properties. This particular zone of the tunnel required the addition of longer rockbolts, and a discussion of that supplemental rock reinforcement will be included