Drought in the Colorado River Basin: Spatiotemporal Analysis using an Edge Detection Filter

A detailed history of drought variability in the Colorado River Basin for the last half millennium was obtained using tree ring-widths of precipitation sensitive trees as a proxy record of past climatic conditions. A one-dimensional edge detection filter was applied to standardized ring-width indices to identify years with rapid change in ring-width magnitude that may reflect changes in state. Both standardized indices and edge detection outputs were mapped to analyze how the spatial pattern of drought changes over time. A Principal Components Analysis was performed for both the mapped index and edge detection outputs to determine whether there were specific patterns within the data. This data analysis identified repeating spatial patterns between each of the identified drought periods during drought onset, with the first principal component of the edge detection accounting for 60% of the variance in the edge data. A temporal mapping of principal component loadings suggests that the Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation play a significant role in forcing drought onset patterns. Superposed Epoch Analysis and a species-sensitivity analysis revealed that there are differences that exist between the droughts, including variation in the timing of the peak index year relative to the onset of drought (peak edge year), in magnitude of drought response, and in the migration patterns of drought onset, making it difficult to classify the droughts. The edge detection filter was found to be successful in identifying periods of drought onset, illustrating drought onset, and capturing migration of drought areas. The Principal Component Analysis loading patterns suggest that there are specific regions within the Colorado River Basin that vary synchronously during drought onset. Having a better understanding of these repeating regional variations in the Colorado River Basin will lead to improved drought predictability, and aid in water management in the region

Article on New Student Group SHADES

Article profiling a new student group on campus, SHADES, that focuses on ethnicity, gender, and sexuality

The Effect of a One Time Imagery Intervention on Self-Efficacy and Exercise Frequency in a Non-Exercising Population

We all know physical activity is an important part of a healthy lifestyle, yet many people are still living sedentary lifestyles. One theory used to explain why some people exercise, while others do not is self-efficacy theory. Past research has indicated that people\u27s self-efficacy may be related to their exercise behavior. It has also been shown that imagery can positive affect self-efficacy. Past research has shown that there is a relationship between imagery, self-efficacy, and exercise frequency, however no intervention studies have assessed this relationship. Therefore, the purpose of this study was to investigate the effect of a one time imagery intervention on self-efficacy beliefs and exercise frequency in a currently inactive population. Fifty-four participants were separated into three different groups, an imagery group, a group that received information on exercise, and a control group. Participants completed an exercise information and background form, the Exercise Self-Efficacy Questionnaire, the Exercise Information Inventory-Revised and companion scale, pre-intervention (time 1), and then again seven days later (time two), and fourteen days later (time 3). Results revealed that the exercise frequency level increased for all groups. Those in the exercise information group increased their exercise frequency significantly more from time one to time three than those in the imagery group. For scheduling self-efficacy, regardless of the group the participants were in their scheduling self-efficacy scores significantly increased from time one to time three. Although the findings of this study were unexpected, they still add valuable information to the discussion on imagery, self-efficacy, and exercise. Specifically, because this is the first study to assess the above relationship through intervention based research, the findings have highlighted potential limitations for imagery interventions, but more importantly the findings have indicated what future research should focus on including imagery intervention length, individualization of the scripts, and matching the script to the persons current behavior level (e.g., adoption versus maintenance)

Investigation of a novel approach for aquaculture site selection

This study investigated the potential use of two “species distribution models” (SDMs), Mahalanobis Typicality and Maxent, for aquaculture site selection. SDMs are used in ecological studies to predict the spatial distribution of species based on analysis of conditions at locations of known presence or absence. Here the input points are aquaculture sites, rather than species occurrence, thus the models evaluate the parameters at the sites and identify similar areas across the rest of the study area. This is a novel approach that avoids the need for data reclassification and weighting which can be a source of conflict and uncertainty within the commonly used multi-criteria evaluation (MCE) technique. Using pangasius culture in the Mekong Delta, Vietnam, as a case study, Mahalanobis Typicality and Maxent SDMs were evaluated against two models developed using the MCE approach. Mahalanobis Typicality and Maxent assess suitability based on similarity to existing farms, while the MCE approach assesses suitability using optimal values for culture. Mahalanobis Typicality considers the variables to have equal importance whereas Maxent analyses the variables to determine those which influence the distribution of the input data. All of the models indicate there are suitable areas for culture along the two main channels of the Mekong River which are currently used to farm pangasius and also inland in the north and east of the study area. The results show the Mahalanobis Typicality model had more high scoring areas and greater overall similarity than Maxent to the MCE outputs, suggesting, for this case study, it was the most appropriate SDM for aquaculture site selection. With suitable input data, a combined SDM and MCE model would overcome limitations of the individual approaches, allowing more robust planning and management decisions for aquaculture, other stakeholders and the environment

A model for optimization of the productivity and bioremediation efficiency of marine integrated multitrophic aquaculture

Integrated multitrophic aquaculture (IMTA) has been proposed as a solution to nutrient enrichment generated by intensive fish mariculture. In order to evaluate the potential of IMTA as a nutrient bioremediation method it is essential to know the ratio of fed to extractive organisms required for the removal of a given proportion of the waste nutrients. This ratio depends on the species that compose the IMTA system, on the environmental conditions and on production practices at a target site. Due to the complexity of IMTA the development of a model is essential for designing efficient IMTA systems. In this study, a generic nutrient flux model for IMTA was developed and used to assess the potential of IMTA as a method for nutrient bioremediation. A baseline simulation consisting of three growth models for Atlantic salmon Salmo salar, the sea urchin Paracentrotus lividus and for the macroalgae Ulva sp. is described. The three growth models interact with each other and with their surrounding environment and they are all linked via processes that affect the release and assimilation of particulate organic nitrogen (PON) and dissolved inorganic nitrogen (DIN). The model forcing functions are environmental parameters with temporal variations that enables investigation of the understanding of interactions among IMTA components and of the effect of environmental parameters. The baseline simulation has been developed for marine species in a virtually closed system in which hydrodynamic influences on the system are not considered. The model can be used as a predictive tool for comparing the nitrogen bioremediation efficiency of IMTA systems under different environmental conditions (temperature, irradiance and ambient nutrient concentration) and production practices, for example seaweed harvesting frequency, seaweed culture depth, nitrogen content of feed and others, or of IMTA systems with varying combinations of cultured species and can be extended to open water IMTA once coupled with waste distribution models

Body dissatisfaction and self-esteem among male college students

The purpose of this study was to examine self-esteem, exposure to the media\u27s portrayal of the ideal male body, and athletic standing of college-aged men in relation to body dissatisfaction. College men (N= 100) were surveyed on these variables. It was hypothesized that males with greater body dissatisfaction would have lower levels of self-esteem. Further, it was expected that males who were more frequently exposed to the body ideal would have higher levels of body dissatisfaction, and that males who do not participate in a college sport would have higher levels of body dissatisfaction than those who do. Results show a significant relationship between body dissatisfaction and self-esteem, such that high levels of body dissatisfaction are associated with low levels of self-esteem. A positive correlation was found between exposure to the media ideal and levels of body dissatisfaction, such that increased exposure was associated with high levels of body dissatisfaction. No significant correlation was found between athletic status and body dissatisfaction. Results of the current study add to previous literature, as well as focus on the college-aged male population