The American West: Out of Myth, Into Reality

Review of: The American West: Out of Myth, Into Reality. Hassrick, Peter H

Employee Engagement in an Animal Research Facility

Disengaged employees can compromise organizational growth. In this qualitative, single-case study, participants discussed their perceptions leading to engagement or disengagement while working at the facility. The characterization of the negative organizational and social effects of employee disengagement may lead to improvements in employee satisfaction, business growth, integrity, and animal welfare.https://scholarworks.waldenu.edu/archivedposters/1088/thumbnail.jp

The American West: Out of Myth, Into Reality

Review of: The American West: Out of Myth, Into Reality. Hassrick, Peter H

Diel periodicity and chronology of upstream migration in yellowphase American Eels (Anguilla rostrata)

This thesis examined 24-h diel periodicity of upstream migration of yellow-phase American Eels (Anguilla rostrata), and the chronology of upstream movements within diel periods (day, night, and twilight). Further, relationships were examined for total lengths of upstream migrants and diel movements (vespertine, nocturnal, matutinal, and diurnal), as well as for total lengths and season of year. The thesis is comprised of two chapters: (1) an introduction and literature review on American Eel life history, migration and movement, and population concerns, and (2) a research study of diel periodicity and movement chronology of upstream migrant yellow-phase American Eels at an eel ladder. Study objectives were to (1) examine diel periodicity of upstream migrants using time-series spectral analysis, (2) describe the distribution of passage counts during diel periods (day, twilight, and night) among seasons (spring, summer, and fall), and (3) examine size of upstream migrants relative to diel and seasonal periods. Data were collected at the Millville Dam eel ladder on the lower Shenandoah River, West Virginia, from 2011--2014. Six multi-day passage events with a high number of passage counts were selected for analysis and categorized by season (spring, summer, late summer/early fall, fall) and diel periods of movement (vespertine, nocturnal, matutinal, and diurnal). To examine diel periodicity of movements, I graphically-depicted passage count data as time-series histograms (10-min bins) and used time-series spectral analysis (Fast Fourier Transformation, FFT) to identify cyclical patterns and periodicity of upstream migration. I also pooled histogram data into 14-h periods (18:00--08:00 hours) using 10-min bins for each multi-day passage event (representing vespertine, nocturnal, and matutinal movements). Using pooled 14-h histograms, I examined patterns of movements for each passage event and described multiple peaks of passage counts for vespertine, nocturnal, and matutinal movements by fitting a normal model and eight normal mixture models (2--9 mixtures). The Bayesian information criterion (BIC) was used to select the best approximating model. A mixed-model methodology was used to examine relationships among total length (TL), diel period, and season. Periodicity of movements closely followed a 24-h cycle of activity with most movement being nocturnal. Based on mixture model analysis, multimodal models were supported by the data, but distribution patterns and timing of upstream migration were complex and variable across the six passage events. An additive-effects model of diel period + season was selected as the best approximating model for the mixed-model analysis of TL. Also, the mean TL of individuals using the eel ladder decreased as the night progressed (i.e., from vespertine to diurnal periods of movement) and was the highest during fall (330.3 mm +/- 1.9 SE, n = 472) relative to similar mean values of TL for spring (304.1 mm +/- 1.0 SE, n = 1700), summer (301.2 mm +/- 1.1 SE, n = 1548) and late summer/early fall (303.4 mm +/- 0.87 SE, n = 2269). This study increased our understanding of upstream migration ecology of yellow-phase American Eels and dam passage at the Millville Dam eel ladder

A System-Wide Approach to Universal Design for Learning Implementation

Universal Design for Learning (UDL), an instructional framework based in neuroscience, optimizes teaching and learning by supporting learners through three overarching principles: Multiple Means of Engagement, Multiple Means Representation, and Multiple Means of Action and Expression (?About universal?). These principles and the subsequent framework that grew out of the work of CAST co-founders and framework co-creators Dr. David Rose and Anne Meyers has become greater than the sum of its parts. Practitioners who have even dabbled in Universal Design for Learning have likely come to the understanding that UDL is a student-centered value system of flexibility, accessibility, and high standards for all students; indeed, the goal of Universal Design for Learning is to create learning environments where students grow to be experts in their own learning. The Every Student Succeeds Act (ESSA) defines and endorses Universal Design for Learning as the framework for designing learning experiences that support the success of all learner

Following Darwin's footsteps using 'the most wonderful plants in the world': the ecophysiological responses of the carnivorous plant Drosera rotundifolia to nitrogen availability.

Nitrogen (N) is an essential element to plants for growth, maintenance and reproduction, however most N does not exist in a form that is biologically available to plants. In order to maximise the acquisition and retention of N, plants have evolved a variety of morphological and physiological adaptations and life history strategies, as well as the ability to respond plastically to changes in resource availability in ecological time. Determining the ecophysiological responses of plants to changes in root N availability is crucial to further understanding of the mechanisms underlying competitive interactions between plants, and between plants and other organisms, that ultimately contribute to community structure and ecosystem functioning. Carnivorous plants are ideal systems for investigating ecophysiological responses to N availability as:- (i) they share a unique adaptation for obtaining supplemental N from captured prey, therefore ecological stoichiometry and energetic cost/benefit models may be explored; (ii) the trait of botanical carnivory is widely considered to have independently co-evolved as a response to N-deficient, sunny and wet environments, therefore resource allocation trade-offs between plant investment in N and carbon (C) acquisition may be observed, and (iii) they are extremely sensitive to changes in root N availability in ecological time. In this research, the carnivorous plant Drosera rotundifolia (round-leaved sundew) was used to address several unanswered ecophysiological and evolutionary questions relating to patterns and processes of prey capture and the N nutrition of carnivorous plants. Furthermore, the potential for reducing uncertainty in the calculation of plant reliance on carnivory using a δ15N natural abundance multi-level linear mixing model was explored. A combined approach of in-situ and ex-situ studies was employed, using co-occurring non-carnivorous plants or carnivorous plant species with differing evolutionary lineages or prey capture mechanisms respectively to provide context. Results show that the adaptations of carnivory, high reproductive investment and a relatively short life span enable Drosera rotundifolia to survive and thrive in an extreme, N deficient environment. Phenotypically plastic responses by the plant to light and root N availability provide evidence of resource allocation trade-offs between investment in carnivory for N acquisition and in photosynthesis for C acquisition. Plants invested less heavily in prey capture (measured as the stickiness of leaf mucilage) as N availability increased or light availability decreased. These results show that the energetic costs associated with carnivory are avoided by the plant when less costly sources of N are available for uptake and that the production of carbon-rich mucilage is only made under nutrient-limited and well-lit conditions. Results obtained from the comparison of captured insect prey with background invertebrates of potential prey indicate that Drosera rotundifolia is a dietary generalist, where the quantity of prey captured per plant is positively correlated with leaf stickiness and total leaf area. Plant reliance on prey-derived N decreased with increasing root N availability, providing evidence that carnivory is only of net benefit to the plant in N-deficient and well-lit environments, as the photosynthetic costs of investment in the trait are not exceeded by the energetic gain from prey N uptake in shady or dry habitats. A more accurate and precise method for calculating plant reliance on botanical carnivory is presented which incorporates the insect diet of the plant. This method has wider significance for reducing uncertainty in the calculation of relative source contributions to a mixture for most natural abundance applications using a multi-level linear mixing model. To conclude, results from this research further understanding of the ecophysiological mechanisms underlying plant responses to changes in resource availability and the selective pressures driving the evolution of plant adaptations. These results therefore assist with predicting how plants and plant communities may respond to sustained N deposition inputs and future environmental scenarios