While they are pregnant and rearing pups, bats continue to leave their roosts to forage for food. Many bats use echolocation vocalizations as part of this process. Other mammalian species including primates experience changes in vocal characteristics during pregnancy and lactation. As echolocation is a vital tool for spatial navigation and prey detection in most bats, investigating echolocation characteristics during pregnancy through lactation may provide new insight into how reproduction, pregnancy and pup rearing influence vocalizations. We measured changes in mass and recorded echolocation calls of pregnant (n = 21) and non-pregnant (n = 2) female wild-caught big brown bats (Eptesicus fuscus) released by hand into roost emergence-like flight. Recording began ~15 days prepartum and ended when the last bat reached 34 days postpartum, when pups were expected to be weaned. Analyses were completed using MATLAB and R, primarily with repeated measures ANOVAs focused on echolocation calls present in the ~562 ms before and ~562 ms after take-off. Based on vocal changes experienced by humans during pregnancy and post-birth, correlations found between bat echolocation call characteristics and the effects of differences in mass on bat echolocation, we predicted that female bats in late-stage pregnancy would emit calls of shorter duration, longer pulse interval, narrower bandwidth, and lower centroid frequency compared to calls emitted by the same bat post-parturition and compared to non-pregnant bats, while source level remained unchanged. We found that pulse interval and source level did not change while pregnant/lactating or control bats were in flight, and that increases in call duration and decreases in centroid frequency and bandwidth in flight began in pregnancy and continued through the lactation period while remaining unchanged for the control bats. / Thesis / Master of Science (MSc) / The goals of this study were to see if big brown bats change the way that they echolocate while they are pregnant and/or nursing pups, and what changes occur. We did this by recording the vocal sounds bats made while they were pregnant and after they had given birth, and looking to see if there were any changes in the duration of echolocation calls, the time between individual sounds, the range of sound frequencies in each call, the central sound frequency in each call, and each call’s sound pressure level over this time and compared to non-pregnant/nursing female big brown bats. We found that echolocation call duration increases over pregnancy and nursing pups, while frequency range and the centre frequency decreases.

For a year and a spring semester, I have been in the works of a school music project. I set out to make a record of ten self-penned songs. Along the length of the project, I would discover musicians and recording artists. I notated my songs on a staff and recorded demos to assist players of drums, electric bass, French horn, and violin. I play guitar, percussion, synthesized instruments, and do all of the singing on Brown Study, the record's title. The technology used to create the songs include a Tascam 2488 (home digital recording device), computers, printers, cell phones and i-phones, amplifiers, microphones and headphones, and a drum machine. This is my first attempt at collaborating with other musicians. At the defense I will be presenting 4 songs: "Runaway," "Lonely Heart," "Topsy Turvy," and "Friendliest Advice." Each song has a particular history and story to tell containing influences and aesthetic philosophies. My gift is to be shared with whoever will listen upon completing and distributing the full-length album.

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Regression analyses and delta-lognormal models were used to investigate whether river discharge and environmental variables significantly affected relative abundance of brown shrimp, Farfantepenaeus aztecus, in the northern Gulf of Mexico. Significant negative relationships were found between mean river flow during winter and spring months and catch rates (CPUE) off Texas, Louisiana and Mississippi/Alabama. However, during the same months significant positive relationships between CPUE and the variation in mean river discharge were found for each state. In Texas and Louisiana, delta-lognormal models revealed depth zone was the most significant variable (P≤0.001) in describing distribution, while time of day (P≤0.001) was most significant in describing CPUE and also distribution and CPUE in Mississippi/Alabama. These results suggest that brown shrimp relative abundance is effected by river discharge, while gulf-wide environmental variables exert no influence, except dissolved oxygen concentrations affecting distribution off Louisiana.

<p> Fragmentation during encounters between protostellar disks provides a possible scenario for the formation of substellar objects such as brown dwarfs and planets. A series of simulations of protostellar disk encounters were performed to investigate the fragmentation under different encounter parameters, and to characterize the properties of any resultant fragments. It was found that the initial disk minimum Toomre Q must satisfy Qini ;S 1.1 for the fragmentation to be induced by the encounters. Fragments of substellar mass can form via disk fragmentation, shock layer fragmentation and tidal tail fragmentation, and the effectiveness of each mechanism is closely related to the initial disk configuration. The fragmentation is also constrained by the relative encounter velocity since the number of fragments decreases quickly with increasing velocity. </p> <p> In comparing to previous studies of protostellar disk encounters it was also found that resolving both the local Jeans Mass during the encounter and the disks' vertical structure are critical to prevent artificial fragmentation and give the correct picture. Heating and cooling rates were estimated in both the optically thin and thick regimes. The comparison between the two indicates that during strong impacts the heating rate increases rapidly but is still comparable to the cooling rate, so the locally isothermal equation of state used in this study is an acceptable approximation. </p> <p> 32 clumps formed in various Qini = 0.9 disk-disk encounters were taken as the sample in an analysis of fragment properties and prospects for their further evolution. The results show that the clump masses are all less than the hydrogen burning mass limit ~ 0.075M0 , so the objects are substellar. Most of the clumps are of brown dwarf mass since the formation of planetary mass clumps is suppressed due to numerical resolution. The mass distribution is broadly consistent to the observed initial mass function in Pleiades. The clumps have highly flattened disk-like shapes and possess large spin angular momentum, which implies that young brown dwarfs may develop disks, jets, or planetary mass companions. About one third of the fragments are unbound to the stars and likely to form free floating brown dwarfs. Orbital analyses of the clumps which are bound to the stars show that there is a lack of close brown dwarf companions ( R < 3 AU), which is consistent to the observed "brown dwarf desert". Many of the orbits are highly eccentric and intersect with other orbits, so ejection of some clumps due to gravitational scattering is likely. Also, dispersion of gas during the encounter and the high spin angular momentum of the clumps may provide mechanisms other than ejection to prevent the clumps from accreting more mass, making the simulated clumps representative of the long term substellar mass function. </p> / Thesis / Master of Science (MSc)

BACKGROUND: There has been renewed interest in the study of brown adipose tissue (BAT) as a potential therapeutic target for obesity, diabetes and non-alcoholic fatty liver disease (NAFLD). There is now much evidence to suggest that BAT is not only important in thermogenesis but also plays an important role in metabolism. In adults, cold-induced BAT activation has led to a significant increase in insulin sensitivity and energy expenditure as well as decreased blood sugar levels. Thus, it is important to identify factors associated with these metabolic disorders such as the presence and activity of BAT to better understand if and how BAT can be targeted to treat these disorders. However, as a potential therapeutic target, it is important to develop accurate, precise, robust and reproducible non-invasive modalities to measure BAT. PROJECT OBJECTIVES: 1) Develop and assess protocols for the use of MRI in measuring BAT characteristics and activity 2) Examine the relationship between BAT MR outcomes and known covariates such as age, sex, body fat percentage and outdoor temperature in adult humans 3) Determine if there is any association between BAT outcomes and liver fat in adult humans, before and after adjusting for potential covariates of liver fat such as age, sex and body fat percentage METHODS: In total, 36 healthy participants (i.e. no conditions or medications that could influence BAT metabolism and/or liver disease) aged 18 to 60 years were recruited to this cross-sectional study. There were two study visits. In visit 1, anthropometrics (i.e. height, weight and waist circumference), blood pressure and body composition (via dual x-ray energy absorptiometry) were measured. Additionally, fasting bloodwork was collected and a 75-g oral glucose tolerance test (OGTT) was administered. During visit 2, participants were exposed to a standardized cold exposure set at 18°C for 3 hours using a water-perfused suit. MRI scans were acquired to evaluate changes in fat-fraction (FF%) and T2* relaxation (T2*) (BAT MR outcomes), liver fat and abdominal fat after a cold exposure. During the cold exposure protocol, mean skin temperature (MST) was monitored using 12 wireless temperature loggers placed at different sites of the body while electromyography (EMG) was used to measure shivering intensity. RESULTS: In the current study, an MRI protocol capable of detecting BAT in the supraclavicular (SCV) region was developed. This protocol included the use of FF and T2* masks to more accurately characterize BAT in the SCV region. Additionally, the MR segmentation protocol was found to be very reliable, as demonstrated by excellent ICC values (i.e. ICCagreement and ICCconsistency ≥ 0.90) for all BAT MR outcomes irrespective of cold exposure. As expected, FF% (mean difference = -2.97; p < 0.0001*) and T2* (mean difference = -0.84; p < 0.0001*) values in the SCV significantly decreased after cold exposure, consistent with BAT activation. Furthermore, the decline in both FF% and T2* after cooling was specific to the SCV region, as these changes did not occur in the posterior neck fat. In examining the relationship between BAT MR outcomes and known covariates of BAT (i.e. age, sex, body fat percentage and outdoor temperature), it is important to note that lower FF% or T2* values are reflective of a browner phenotype while a greater reduction in FF% is indicative of higher BAT activity. BAT characteristics (A: pre-cold FF%; B: pre-cold T2*) and BAT activity (C: FF% reduction) were correlated with age (A: r = 0.54; p = 0.0007*; B: r = 0.42; p = 0.0112*; C: r = -0.39; p = 0.0213*) and body fat percentage (A: r = 0.83; p < 0.0001*; B: r = 0.58; p = 0.0002*; C: r = -0.64; p < 0.0001*). That is, higher age and body fat were associated with a less brown phenotype prior to cold exposure and with less BAT activity (i.e. lower FF% decline) in response to cold exposure. However, no associations were found between BAT MR outcomes and sex or outdoor temperature. Lastly, liver fat was associated with higher values of pre-cold FF% (r = 0.60; p < 0.0001*) and pre-cold T2* (r = 0.47; p = 0.0040*) while FF% reduction was inversely correlated with liver fat (r = -0.38; p = 0.0295*). Additionally, the relationship between BAT MR outcomes and liver fat still existed after adjusting for age and sex while its effects were mediated by adiposity. CONCLUSION: In this study, a highly reliable MR segmentation protocol was developed that is capable of measuring BAT characteristics and activity irrespective of cold exposure. Additionally, the cold exposure protocol used was sufficient to elicit changes in BAT MR outcomes, as demonstrated by significant changes in FF% and T2* after cooling. Consistent with previous studies, BAT outcomes (as measured by MRI) were associated with age and body fat percentage. Lastly, findings in this thesis provide strong supporting data that BAT may regulate liver lipid content, however, the extent and mechanisms remain to be determined. / Thesis / Master of Science (MSc)

<p> The mtDNA control region of the Brown-headed Cowbird (Molothrus ater) was sequenced and comparisons made at the inter- and intraspecific level. Comparison of the control region with that of another Passerine, Darwin's Finch (Geospiza scandens), revealed a high degree of both gross and fine scale structural similarity. At the nucleotide level, this comparison confirmed the presence of a hypervariable domain which evolves at rate approximately 5 times faster than coding mtDNA as well as a relatively conserved central domain which evolves at rate comparable to coding mtDNA. Both species displayed the typical avian mtDNA gene organisation previously described by Desjardins and Morais (1990, 1991) and Quinn and Wilson (in press). However, the most notable structural feature in common was the apparent deletion of the entire left hypervariable domain (CR1). At a finer scale, Conserved Sequence Block (CSB1) was perfectly conserved between cowbird and finch and Conserved Sequence Block 2 (CSB2) was 78% similar. The hypervariable right domain showed the largest degree of sequence divergence between species, 22.7%, while the central domain and phe-tRNA showed much less divergence, 6.47 and 4.41% respectively. At an intraspecific level, in 524 bases of sequence from 31 nestling cowbirds from a population at Delta, Manitoba, only 3 variable sites were detected which defined a total of 4 haplotypes. The average percent sequence divergence for this population was 0.27%. This level of variation within the cowbird population is low compared to other vertebrate populations. This relative lack of variation is largely attributable to the loss of the left hypervariable domain (CR1). The loss of CR1 will limit the control region's usefulness for high resolution population level studies but may make it a useful marker for phylogenetic studies within the class Aves.</p> / Thesis / Master of Science (MSc)

Uncoupling protein, a mitochondrial inner membrane protein found in mammalian brown adipose tissue, functions as an uncoupler of oxidative phosphorylation by serving as a proton carrier when activated, resulting in heat production, the function of the tissue. Unlike most nuclear-encoded mitochondrial proteins, uncoupling protein is not made with a cleavable presequence. With the availability of an uncoupling protein cDNA clone, the region responsible for targeting uncoupling protein to mitochondria was examined using in vitro transcription and translation and import into isolated mitochondria. In order to localize the targeting sequence of uncoupling protein, fusion proteins containing portions of uncoupling protein and uncoupling protein modified by site-directed mutagenesis were constructed and analysed for their ability to be imported. Previously it has been shown that there was a targeting signal within uncoupling protein amino acids 13 to 105 (Liu et al., 1988). However, amino acids 13 to 51 did not target a passenger protein to mitochondria (Liu et al., 1988). Here the role of amino acids 53 to 105 of uncoupling protein in targeting was examined with two new constructs, uncoupling protein amino acids 53 to 105 joined to rat ornithine carbamoyltransferase amino acids 147 to 354 and to mouse dihydrofolate reductase. These two constructs along with uncoupling protein with amino acids 2 to 51 deleted were imported into mitochondria consistent with uncoupling protein amino acids 53 to 105 having a potential targeting role in uncoupling protein. Further, these three constructs were processed upon import. The major processed forms of all three constructs are approximately 20 amino acids smaller than the initial translation product. Both fusion constructs also have an intermediate-sized processed form approximately 14 amino acids smaller than the initial translation product. Processing suggests that at least the amino terminus of these proteins has reached the mitochondrial matrix. The location of the proteins was examined using Na2CO3 extraction. Uncoupling protein and U13-105-OCT (uncoupling protein amino acids 13 to 105 joined to ornithine carbamoyltransferase amino acids 147 to 354) were found in the membrane fraction while the processed forms of Ud2-51 (uncoupling protein with amino acids 2 to 52 deleted) and U53-105-DHFR (uncoupling protein amino acids 53 to 105 joined to dihydrofolate reductase) were found in the aqueous fraction suggesting that uncoupling protein amino acids 2 to 52/53 are involved in membrane localization. Analysis of Ud2-35 (uncoupling protein with amino acids 2 to 35 deleted) revealed that it was associated with both the membrane and aqueous fractions. Analysis of uncoupling protein amino acids 53 to 105 revealed the potential existence of two positively charged amphipathic a-helices. Based on the sizes of processed forms and on the helical wheel projection for the first possible sequence, arginine54 , lysine56 and lysine67 were changed to glutamines, individually and in various combinations using oligonucleotide site-directed mutagenesis. All mutant proteins were imported into mitochondria even when all three basic amino acids were replaced. The results suggest that this portion of uncoupling protein, amino acids 54 to 67, is not a targeting signal in the protein. / Thesis / Master of Science (MS)

Insectivorous bats alter relative use of metabolic substrates to match requirements of their activities, including energetically expensive flight. The “fasting while foraging” hypothesis states that the metabolic demands of flight often exceed energy intake while foraging, hence bats may metabolize fat stores (especially early in the night) to power flight with ketones, a byproduct of the normal oxidation of fatty acids. Previous studies in bats have found increases in the plasma ketone ß-hydroxybutyrate following food consumption paired with or without flight. However, no study has explored whether increases in plasma ß-hydroxybutyrate occur following flight without food consumption. We used metabolite analysis to examine changes in plasma ß-hydroxybutyrate as a function of flight duration in 2 groups (fall and spring) of captive big brown bats (Eptesicus fuscus). We fasted bats for 12 hours prior to flight (exercise treatment) or rest (control), and then collected interfemoral vein blood. Exercise activity was quantified as flight time. For the Fall group, we collected three rest samples and one flight sample. Results for the Fall group were variable; interpretation of data patterns for this group may be complicated by changes in metabolism that occur in the fall when bats physiologically prepare for hibernation. To control for seasonal effects, we tested a second group of bats in the spring, collecting two rest and three flight samples. We found a positive correlation between flight duration and levels of plasma ß-hydroxybutyrate in the Spring group, which supports the fasting while foraging hypothesis. / Thesis / Master of Science (MSc) / The “fasting while foraging” hypothesis states that the metabolic demands of flight can exceed energy intake from recently consumed prey items, so insectivorous bats may metabolize fat stores (especially early in the night) to power flight with ketones, a byproduct of the normal oxidation of fatty acids. Previous studies in bats have found increases in the plasma ketone ß-hydroxybutyrate following food consumption, but no study has explored whether increases in plasma ß-hydroxybutyrate occur following flight without food consumption. We collected and analyzed blood to examine changes in plasma ß-hydroxybutyrate following different flight durations in big brown bats. We explored both seasonal and captivity effects. To explore seasonal effects, we sampled blood from bats in the fall and the spring, times that are biologically significant to big brown bats. The spring is when bats move out of torpor, a form of hibernation, into an active state and the fall is when bats are preparing for entering into torpor. To explore captivity effects, we sampled blood from bats recently introduced to or established to captivity. Bats were fasted for 12 hours prior to flight (exercise treatment) or rest (control), and then blood was collected. We characterized exercise using flight time. We found that plasma ß-hydroxybutyrate increased after longer flight durations, which supports the fasting while foraging hypothesis.