Muscle glycogen and blood lactate in yellowfin tuna, Thunnus albacares, and skipjack, Katsuwonus pelamis, following capture and tagging

ENGLISH: Tagging and the recovery of tagged yellowfin (Thunnus albacares) and skipjack (Katsuwonus pelamis) tunas are important aspects of the investigations conducted by the Inter-American Tropical Tuna Commission in the Eastern Tropical Pacific Ocean. The results of the tagging program provide information on population structures, migrations, mortality rates and growth rates of these two species. The present experimental program was undertaken to study the relationship between muscular fatigue and high tagging mortalities in yellowfin and skipjack. SPANISH: La marcación del atún aleta amarilla (Thunnus albacares) y del barrilete (Katsuwonus pelamis), y el recobro de estos atunes marcados, son aspectos importantes de la investigación que efectúa la Comisión Interamericana del Atún Tropical en el Océano Pacífico Oriental Tropical. Los resultados del programa de marcación proporcionan información sobre la estructura de las poblaciones, migraciones, tasas de mortalidad y tasas de crecimiento de estas dos especies. El programa experimental presente fue emprendido para estudiar la relación entre la fatiga muscular y la alta mortalidad causada por la marcación en el atún aleta amarilla y el barrilete. (PDF contains 52 pages.

Continuum modeling of active nematics via data-driven equation discovery

Data-driven modeling seeks to extract a parsimonious model for a physical system directly from measurement data. One of the most interpretable of these methods is Sparse Identification of Nonlinear Dynamics (SINDy), which selects a relatively sparse linear combination of model terms from a large set of (possibly nonlinear) candidates via optimization. This technique has shown promise for synthetic data generated by numerical simulations but the application of the techniques to real data is less developed. This dissertation applies SINDy to video data from a bio-inspired system of mictrotubule-motor protein assemblies, an example of nonequilibrium dynamics that has posed a significant modelling challenge for more than a decade. In particular, we constrain SINDy to discover a partial differential equation (PDE) model that approximates the time evolution of microtubule orientation. The discovered model is relatively simple but reproduces many of the characteristics of the experimental data. The properties of the discovered PDE model are explored through stability analysis and numerical simulation; it is then compared to previously proposed models in the literature. Chapter 1 provides an introduction and motivation for pursuing a data driven modeling approach for active nematic systems by introducing the Sparse Identification of Nonlinear Dynamics (SINDy) modeling procedure and active nematic systems. Chapter 2 lays the foundation for modeling of active nematics to better understand the model space that is searched. Chapter 3 gives some preliminary considerations for using the SINDy algorithm and proposes several approaches to mitigate common errors. Chapter 4 treats the example problem of rediscovering a governing partial differential equation for active nematics from simulated data including some of the specific challenges that arise for discovery even in the absence of noise. Chapter 5 details the procedure for extracting data from experimental observations for use with the SINDy procedure and details tests to validate the accuracy of the extracted data. Chapter 6 presents the active nematic model extracted from experimental data via SINDy, compares its properties with previously proposed models, and provides numerical results of its simulation. Finally, Chapter 7 presents conclusions from the work and provides future directions for both active nematic systems and data-driven modeling in related systems

Blood lactate in yellowfin tuna, Neothunnus macropterus, and skipjack, Katsuwonus pelamis, following capture and tagging

ENGLISH: The staff of the Inter-American Tropical Tuna Commission for several years has been investigating the life history, population structure, behavior and ecology of the yellowfin tuna, Neothunnus macropterus, and the skipjack, Katsuwonus pelamis, in the Eastern Tropical Pacific Ocean. The tagging and subsequent recovery of these tropical tunas, to provide information on population structure, migrations, mortality rates and growth rates, are important aspects of these investigations. Broadhead (1959) and Schaefer, Chatwin and Broadhead (1961) emphasize the many difficulties involved in tagging these extremely active yet delicate fish and give considerable evidence to suggest that tagging mortality is high, perhaps as great as 60 to 80 per cent. The latter authors suggest that the rather high mortality at tagging is related to the effects of hyperactivity brought about by the tagging operation. SPANISH: El personal de la Comisión Interamericana del Atún Tropical ha estado investigando durante varios años la historia natural, la estructura de la población, los hábitos y la ecología del atún aleta amarilla, Neothunnus macropterus, y del barrilete, Katsuwonus pelamis, en el Océano Pacífico Oriental Tropical. La marcación y el subsiguiente recobro de estos atunes tropicales, lo que da información sobre la estructura de la población, los movimientos migratorios y las tasas de crecimiento y de mortalidad, son importantes aspectos de estas investigaciones. Broadhead (1959) y Schaefer, Chatwin y Broadhead (1961) destacan las muchas dificultades que hay para marcar estos peces activos en extremo pero delicados, y proporcionan considerable evidencia que sugiere que la mortalidad por la marcación es bastante alta, siendo quizás de 60 a 80 por ciento. Los autores citados sugieren que esta elevada mortalidad por la marcación está relacionada con los efectos de la hiperactividad producida por la operación de marcación

Using Implantable Tags to Investigate the Free-Swimming Activity and Bioenergetics of Largemouth Bass and Lake Trout

Accurately assessing free-swimming activity, energy use, and behaviour remains challenging, but is important in advancing our ability to predict factors that influence movements, foraging, reproduction, and survival. These measurements are also valuable to improve bioenergetics models which rarely incorporate free-swimming measurements. Tagging devices may be used to estimate these endpoints; however, this requires prior calibrations which relate recordings of activity, metabolism, or the target behaviour to tag recordings (e.g., acceleration). I my thesis, I sought to 1) expand the scope of free-swimming measurements that can be collected from tagged largemouth bass (Micropterus nigiricans) and lake trout (Salvelinus namaykush) using swim performance and behavioural calibrations, 2) advance our understanding of their free-swimming activity and energy use, and 3) improve their bioenergetics models. Additionally, as winter-specific bioenergetics measurements are presumably lacking, throughout my research there is an emphasis on winter or cold-water. To contextualize the importance of cold-water bioenergetics research, I reviewed existing literature on cold-water bioenergetics research in freshwater fish. My results indicated that there was a lack of cold-water bioenergetics measurements for certain parameters and that less than half of the bioenergetics models reviewed included cold-water measurements in their derivations. Using swim tunnel respirometry, I produced calibrations which allow the estimation of swimming speed and metabolism in free-swimming lake trout and largemouth bass across an environmentally relevant range of temperatures. I later assessed largemouth bass’ overwinter activity and energy use, estimated using my previously derived lab calibrations. Generally, activity, heart rate, and metabolic rate decreased with fall cooling, remained low over the winter, increased with spring warming, and peaked in the late spring coinciding with their spawning period. Bioenergetics modeling indicated that bass engaged in overwinter feeding to explain observed weight changes which were highly variable. I also explored whether tags could be calibrated to predict sea lamprey attacks on free-swimming lake trout. Predictive models produced were able to identify periods when sea lamprey were attached to trout with reasonable accuracy but data noise caused by tag movement within the body seemed to impair model performance. Modifications to the surgical procedure may improve model accuracy if further developed

The Effectiveness of Modern Advertising at Achieving Brand Remembrance

The relationship between aspects of modern commercial advertising, such as use of storytelling, positive and negative emotional factors, and message content, and their effect on achieving correct brand remembrance with the commercial’s viewers was studied. One hundred sixty subjects completed a survey that prompted them to remember the brands associated with five different commercials shown during the 2015 Super Bowl, as well as asked other questions about each commercial and the subjects’ television viewing habits. Results showed that a very small percentage of viewers correctly remembered the brand associated with commercials they had seen, and that this correct brand remembrance can be influenced by the aforementioned advertising methods and psychological factors

Bayesian calibration of stochastic agent based model via random forest

Agent-based models (ABM) provide an excellent framework for modeling outbreaks and interventions in epidemiology by explicitly accounting for diverse individual interactions and environments. However, these models are usually stochastic and highly parametrized, requiring precise calibration for predictive performance. When considering realistic numbers of agents and properly accounting for stochasticity, this high dimensional calibration can be computationally prohibitive. This paper presents a random forest based surrogate modeling technique to accelerate the evaluation of ABMs and demonstrates its use to calibrate an epidemiological ABM named CityCOVID via Markov chain Monte Carlo (MCMC). The technique is first outlined in the context of CityCOVID's quantities of interest, namely hospitalizations and deaths, by exploring dimensionality reduction via temporal decomposition with principal component analysis (PCA) and via sensitivity analysis. The calibration problem is then presented and samples are generated to best match COVID-19 hospitalization and death numbers in Chicago from March to June in 2020. These results are compared with previous approximate Bayesian calibration (IMABC) results and their predictive performance is analyzed showing improved performance with a reduction in computation

Primer for Directors of Not-for-Profit Corporations: Rights, Duties and Practices

Directors of not-for-profit corporations are, like the organizations they serve, a diverse lot. Perhaps the two characteristics they are all most likely to share are that they are well-intentioned and time-pressed. This book was created with both these factors in mind. We have attempted to prepare a text that will help directors do a good job, as well as protect themselves from potential claims arising from their actions or decisions. We have also attempted to do so in a friendly fashion that does not require prolonged study, but highlights the essentials of what you need to know