1,267 research outputs found
Identifying significant factors and optimal sites for commercial salmon farming in northern Norway. An integrated GIS and machine learning approach using random forest.
This study presents a data-driven modelling approach to identify important factors influencing
the growth- and mortality rate for farmed salmon in northern Norway. Furthermore, a model
is trained to determine the best fish farming sites and identify optimal areas with the best
geographical conditions.
Aquaculture site production and location data from 323 salmon farming sites (all licensed
aquaculture sites) in northern Norway were obtained from the Directory of Fisheries. Two
dependent variables, growth- and mortality rate, were calculated based on the monthly
increase in biomass and mortality. These variables were combined with state-of-the-art
environmental- and exploratory socio-economic data obtained from the institute of marine
research (IMR), the Norwegian Meteorological Institute, Delft University of Technology,
Norwegian Coastal Administration, and Statistics Norway.
Using random forest regression and recursive feature elimination, a data-driven ensemble
approach identified significant variables. Prediction of optimal sites for salmon farming in
northern Norway was done with a species distribution modelling approach using random
forest classification.
The important factors affecting salmon growth were specific feeding rate, temperature, and
total biomass. The important factors influencing salmon mortality were temperature and total
biomass. The predicted optimal areas were inside Vefsnfjorden, Ranfjorden, Sørfjorden and
Glomfjorden, small areas near the coast and around the small islands stretching from Gladstad
to Narvik. Areas near the coast of Lofoten, Værøy, Røst, Vesterålen, Sortland and Senja.
Further north, some dispersed regions were predicted as optimal outside Tromsø and Sørøya.
Also large areas around Varangerhalvøya, Olderdalen/Kåfjorden, Lille Altafjorden and near
the shore on both sides of Stjernøysundet.
The results clearly show that space is a scares resource and that there is an urge to evaluate
the regulations and legislations concerning aquaculture in Norway. Especially the minimum
distances between the fairways and aquaculture locations. The incorporation of machine
learning approaches in GIS-based MCE analysis is suggested to help planners and decision-makers make informed and sustainable decisions about sea-area use
Effects of Attention Allocation on Habituation to Food Cues in Normal Weight and Overweight Children
ABSTRACT OF THE DISSERTATION Effects of Attention Allocation on Habituation to Food Cues in Normal weight and Overweight Children by Vandana Passi Aspen Doctor of Philosophy in Psychology Washington University in St. Louis, 2010 Professor Denise Wilfley, Chairperson Despite the rising prevalence of pediatric overweight, minimal research has been conducted to understand the basic biological processes underlying overweight in children. The present study assesses changes in physiological response: i.e., salivation) to food over time. The primary aims were to examine whether salivation patterns in children vary based on weight status and/or allocating attention to a distracter task. It was hypothesized that: 1) overweight children would not habituate: salivation at the final trial would not decrease back to baseline level), regardless of distracter task condition while the normal weight children would habituate: i.e., salivation at the final trial would decrease back to baseline level) and that 2) all children attending to the distracter task would take longer to habituate as compared to those not attending to the task. Participants were 31 normal weight and 26 overweight children ages 9 to12 years. All children were presented with nine one-minute trials of a food stimulus: French fries). During each intertrial interval, participants either listened to sequential one-minute presentations of an audio-book: distracter task) or listened to white noise: no-distracter-task control). Pattern and rate of salivation were measured using a validated procedure: the Strongin-Hinsie Peck method) and analyzed using repeated measures ANCOVA and Kaplan-Meier survival analysis. The rate of change in salivation over trials differed significantly by weight status: p = .01) but not by distracter task condition: p \u3e .10). Specifically, regardless of distracter task condition, at the final trial of the study, normal weight children habituated to food cues while overweight children did not. Results suggest that children\u27s physiological response to food is related to weight status. Such atypical habituation patterns could potentially lead to overconsumption, thus serving as a possible causal or maintaining factor in childhood overweight. The lack of a distracter effect is in contrast to previous findings and may be due to differences in methodology across studies. Future directions, including, a) experiments to explore causal mechanisms, b) experiments testing habituation in more naturalistic settings and, c) prospective studies to determine the role of salivary response in OW, are discussed
Essays on the Economics of Electric Vehicle Charging Stations
Electric vehicles (EVs) have peaked people’s interest since the first electric-powered vehicle was developed in the 1830’s. By the 1890’s EVs were the most common vehicle in the U.S. However, due to issues with charging batteries and limitations of the electrical grid, EVs were left behind as gasoline vehicles became commonly available in the early 20th century. Several attempts to repopularize EVs over the last 100 years suffered from difficulties with limited driving ranges, but today, expanded driving ranges and improved charging capabilities have made EVs a real alternative to gasoline engines. The possibility of zero-emission transportation made possible by EVs has fueled both public and private investment in EV charging infrastructure through a variety of subsidies. However, a better understanding of how charging stations are utilized and of the effects of charging station subsidies on drivers and station development is essential. This dissertation studies how charging station subsidies, station location, and prices affect driver charging behavior and new station construction
IDENTIFYING A CONSUMER-PRODUCER AGRICULTURAL KNOWLEDGE GAP
The purpose of this paper and online survey was to see if an agricultural knowledge gap between consumers and producers be found. Low agricultural literacy rates can lead to misconceptions of the agriculture industry, unhealthy food choices, environmentally unfriendly product choices, food waste, etc. The hypothesis for this thesis is that those born in the mid1960s to early 1980s (Generation X) will be the start of an increased knowledge gap. The survey was compiled of both qualitative and quantitative questions and questions were inspired by American Farm Bureau’s AITC Benchmarks. Responses were analyzed and the results revealed that my participants were able to answer AITC Benchmark questions with a \u3e70% correctness. The results of this study were inconclusive of the existence of a knowledge gap across different generations. Future research should survey a more diverse participant pool
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