Optimisation of common snook Centropomus undecimalis broodstock management

Advances in aquaculture technologies are being investigated to support the replenishment of local fisheries, develop marine food fish farming opportunities and to increase seafood production globally. In order to promote the expansion and development of aquaculture technologies required to raise new finfish species, a number of key bottlenecks restricting commercial-scale culture need to be addressed, including the ability to control fish reproduction in captivity and to produce high quality seeds. One candidate species for large-scale production, and the focus of this work, is common snook. Prized as a food fish in Mexico, Central and South America and as a popular game fish along the Gulf coast of the United States; common snook are economically important having both a high market value and recreational demand. Despite recent advances in captive spawning, a number of reproductive bottlenecks still need to be addressed such as lack of spontaneous spawning in captivity, poor fertilization rates and inconsistent production of high quality eggs and larvae. Therefore, the overall aim of this thesis was to better understand the reproductive biology of common snook in order to develop protocols to improve the reliability of captive spawning in closed recirculating aquaculture systems and the quality of eggs produced as a basis for commercial scale cultivation. First, this PhD project described oocyte development in common snook and validated a non-invasive method for assessing reproductive condition in wild and captive stocks (Chapter 2). This was done by using a tiered and adaptable staging scheme to compare the wet mount technique with histological preparations of ovarian biopsies. When compared with histology, the wet mount provided an immediate and precise method for determining whether female broodstock were candidates for hormonal induction. In fishery biology, an understanding of fish reproductive success and population reproductive potential is critical for designing and implementing effective fisheries management strategies. The wet mount technique provides a tool for non-lethal, low-cost determination of reproductive status in wild fish stocks. The next research chapter focused on spawning induction of captive snook populations. The first trial compared the effects of slow and regular release GnRHa implants whereas the second trial investigated the effects of GnRHa, alone or in combination with the dopamine antagonist, pimozide (PIM), on milt characteristics and plasma steroid levels in captive male common snook broodstock (Chapter 3). In an effort to better enable reliable control of reproduction under captive conditions, the annual plasma sex steroid profile of captive male and female broodstock maintained under natural photo-thermal conditions was also examined. When possible, milt samples were collected pre and post implantation; sperm density, sperm motility and spermatocrit were documented among individual males. The assigned treatments appeared to have no or little effects on milt production in male broodstock although plasma steroid levels were found to be significantly elevated in individuals treated with GnRHa in combination with the dopamine antagonist, pimozide. At the time this work was performed, no data on spawning dynamics, including individual spawning performance, had been reported for common snook in captivity. Mass spawning tanks are complex systems where fish are left to spawn naturally and fertilized eggs are collected with little or no control over the mating of the animals. Therefore, the third part of this thesis explored the potential of DNA profiling for monitoring mating outcomes in captive broodstock by employing eight microsatellite markers to detect and quantify individual parental contributions for 2,154 larvae obtained from the three broodstock tanks (Chapter 4). The panel of loci was generally robust and allowed unambiguous assignment of 89% of larvae to a single family. Overall, spawn contribution data 1) provided a confirmation of GnRHa treatment efficacy in female snook with a minimum stage of oogenesis (late secondary growth-SGl) required for successful spawning, 2) identified a potential impact of handling on maturation and spawning of captive broodstock and 3) confirmed that, through photothermal conditioning, captive broodstock can spawn over consecutive days and several times per year including outside of their natural spawning season. The exogenous cues that tropical species use to synchronize key life events like reproduction remain largely unstudied, therefore, my PhD project also investigated the influence of tidal cycle on reproductive activity in common snook (Chapter 5). Real-time quantitative RT-PCR assays were developed and validated to measure the temporal expression patterns of gonadotropin genes (fshβ and lhβ) during the reproductive cycle in males and females. These were evaluated in relation to sex steroid production, LH blood plasma levels, gonadal development and tidal cycle. The phylogenetic analysis of the deduced amino acid sequence of common snook for fshβ and lhβ revealed strong identity with other teleosts (75-90%). Additionally, the mRNA profiles of fshβ and lhβ in the pituitary of females displayed a clear pattern of expression concomitant with histological changes in oocyte development. Histological observations of gonads suggested a circa-tidal rhythm of follicular development. The findings, as a whole, provided new information supporting the role of tidal cycle on the entrainment of gametogenesis allowing for a better understanding of the environmental control of reproduction in common snook. Although the primary research emphasis in this PhD was on broodstock spawning and gamete quality, the final chapter focuses on larval ontogeny. The goal of this research was to gain improve understanding of the early life history characteristics of common snook in order to improve larval culture technologies. To do so, a combination of digital photography and histological techniques were used to document the embryonic and early larval development (0 to 14 days post hatch-DPH) of hatchery-reared individuals (Chapter 6). Larvae hatched 15 h after fertilization at 28°C, lacked pigmentation, had a rudimentary digestive tract and undeveloped visual system. Development was rapid and by 3 DPH larvae had almost doubled in length, the yolk sac was nearly exhausted, the mouth was open and eyes were pigmented with a well-structured retinal layer. The alimentary canal was differentiated into three distinct sections including the foregut, midgut and hindgut. Food was observed in the gut (rotifers) and structural epithelium organelles, such as the nucleus, mitochondria, and dark vesicles, were all present in high numbers. The swim bladder was formed and inflated. In summary, understanding early ontogenetic development in common snook can help provide information needed to address key bottlenecks seen in captive cultivation, such as the high incidence of larval mortality observed during the transition from endogenous to exogenous feeding. Overall, this doctoral work 1) validated molecular and endocrine analytical tools for future studies of common snook reproductive physiology, 2) provided a better understanding of both broodfish requirements in tank systems as well as the endocrine control of reproduction and spawning at the level of the brain-pituitary-gonadal axis, 3) increased our knowledge in genetic management of captive broodstock, in terms of parentage assignment and 4) offered new insight into wild population reproductive strategy as well as how reproduction is entrained through environmental cues and the pathways leading to oocyte recruitment and maturation. The new information presented here can be used to conserve wild snook stocks through production of farm raised individuals as a sustainable source of seafood and for fisheries enhancement

The Heliand: The Warrior\u27s Strength and the Transcendence of Faith

The research project centered on the literary text, Heliand, a biblical paraphrase of the Gospel originally written in Old Saxon in the 9th century. Throughout this period, Christianity was steadily spreading to the pagan lands of northern Europe. Because this initially involved a form cultural clash between the Christian and Germanic world-views, Christianity is often thought to have been an overt replacement of the earlier traditional folk-culture of these lands. The Heliand, though, expresses differently by drawing parallels between the old Germanic warrior culture and the Christian faith. The project examines how this is accomplished by exploring deeper into the specific foundations that defined Germanic tribal culture of the day and how the Heliand appealed to each element in terms of the intimacy of kinship, the heroism of individual conduct and the presence of strong spiritual forces such Fate. Additionally, the project takes into consideration the effects of certain historical events, such as the Saxon Wars and the conversion stories of some of the major Germanic tribes, and the roles they played in the final incorporation of the Germanic culture into Christendom. In the end, this text has given greater insight on how the person of Jesus Christ, as the center of the Christian faith, could also be the ultimate embodiment of the warrior ideology of the northern peoples

Topic Modeling and Figurative Language

Located at the center of Jorie Graham’s collection The End of Beauty, “Self Portrait as Hurray and Delay” crafts a portrait of the artist, poised at a precarious moment in which thought begins to take shape. Like Penelope, Graham entertains the illusion, if only momentarily, of a choice between bringing a creative impulse into form or allowing it to come undone. A weaver of language, Graham subtly, deftly, but unsuccessfully attempts to delay the inevitable moment in poetic creation in which complexity of thought adopts form through language, and so realized is also reduced. In The End of Beauty, the beginning of the creative act signals an inevitable descent into meaning – language’s ultimate impulse. Understanding how topic modeling algorithms handle figurative language means allowing for a similar beautiful failure – not a failure of language, but a necessary inclination toward form that involves a diminishing of language’s possible meanings. However, the necessarily reductive methodology of sorting poetic language into relatively stable categories, as topic modeling suggests, yields precisely the kind of results that literary scholars might hope for – models of language that, having taken form, are at the same moment at odds with the laws of their creation. In the following article, I suggest that topic modeling poetry works, in part, because of its failures. Somewhere between the literary possibility held in a corpus of thousands of English-language poems and the computational rigor of Latent Dirichlet Allocation (LDA), there is an interpretive space that is as vital as the weaving and unraveling at Penelope’s loom

Beyond Darwinian Distance: Situating Distant Reading in a Feminist Ut Pictura Poesis Tradition

Looking from a distance, as a condition of knowledge, participates within a long-standing Western tradition of power relations. This article considers the use of "distant reading" as theorized by Franco Moretti in his book by the same title and suggests that the method of literary analysis that uses such a metaphor should be aware and critical of that tradition. Moreover, this article suggests that we look to examples in literature, such as ekphrastic poetry by women for possible alternative approaches to reading at a distance as an approach to large corpora of text. Essentially, a feminist approach to distant reading is possible and necessary, and this paper calls for making such work more central to our discussions of distant reading by literary scholars

Behavioral differences in depressed and conduct-disordered youth

This study investigated the behavioral parameters of depression in children and adolescents. Demographic information, DSM-III psychiatric diagnosis, scores on the Children\u27s Depression Inventory (CDI), and admitting problem (POR) behaviors were obtained from an archival data pool collected at four different child psychiatric hospitals on 630 inpatient subjects 5 to 20 years of age.;Subjects were assigned to one of four research groups defined by psychiatric diagnosis (DSM-III) and/or by scores on the CDI, i.e., CDI only groups (high vs. low scorers), DSM-III only groups (depressed vs. conduct-disordered), DSM-III + CDI groups (depressed high scorers vs. conduct-disordered low scorers), and DSM-III only (depressed children vs. depressed adolescents). Forty POR behaviors previously identified as being symptoms or associated features of childhood depression were used in a discriminant function analysis for each research question.;There was no difference between groups on POR behaviors when separated only by CDI scores. Results supported some behavioral difference between psychiatrically diagnosed depressed and conduct-disordered youth. Sadness appeared to be the most powerful discriminating variable for predicting depression as separate from conduct disorder when depression was defined by DSM-III criteria alone and in conjunction with CDI cutoff scores of 11 or higher. Aggression was significant in predicting conduct disorder for the DSM-III only groups. Poor self-concept and school underachievement were also indicated as behavior variables having discriminating power when depression was defined by DSM-III only. Age differences in POR behaviors for DSM-III depressed children and adolescents were not significant.;Results were discussed in terms of trends in the data that may be useful for further investigative efforts. The presence of a number of behaviors in DSM-III and DSM-III plus CDI depressed groups supported findings of previous psychometric studies; support was also found for several overlapping behaviors between depressed and conduct-disordered groups as reported in the literature. It was concluded that further behavioral study is needed with depressed children and adolescents to confirm findings from previous psychiatrically and psychometrically based studies. Findings would ultimately be useful in formulating developmental refinements in the assessment criteria for childhood depression and aiding in the differential diagnosis of depression and conduct disorder

Agriculture education majors who graduated from the University of Tennessee College of Agriculture from the summer quarter, 1955, through the summer quarter, 1964

This study was designed as a follow-up study of all agricultural education majors who graduated with a Bachelor of Science degree from The University of Tennessee College of Agriculture, beginning with the summer quarter, 1955, through the summer quarter, 19611-. The primary objective of this study was to determine the occupational status of agricultural education majors and their reasons for selection of such occupations

The Idea of a Post Colonial University

Universities in the English-speaking world may trace their origins to England, where the first universities of Oxford and Cambridge were established. These universities were, for centuries, the models for universities to come both in terms of structure and philosophy; and they also became a tool of British colonial policy. With the progression of British expansionism, many English men penned their ideas of a university; some of which were brought to fruition. In the 21st century, we have a multiplicity of independent nations which were formerly under British rule. While in most societies there was a phasing out of colonial institutions, many universities established during the colonial epoch seem to have withstood the test of time. It would be interesting therefore to assess some of these institutions and their evolutions in a broader endeavour to examine developments in higher education in societies post-independence. What conversations were had prior to independence regarding higher education? What ideas of a post-colonial university prevailed and what ideas should have been put forth? Were there shifts away from what constituted a colonial university? This paper is also an attempt to include universities in the post-colonial discourse and to propose an ideals of the university from a post-colonial perspective

Analysis of critical issues and incidents in the New York City school crisis, 1967-1970, and their implications for urban education in the 1970\u27s.

Abstract not availabl

The reaction to romanticism in the North American Review, 1835-1860

The key to literary Romanticism is dynamic organicism, a principle that, espceially in its negative aspects, frequently gave rise to literary works that were at odds with the world-view of the critics

Working the Digital Humanities: Uncovering Shadows between the Dark and the Light

The following is an exchange between the two authors in response to a paper given by Chun at the “Dark Side of the Digital Humanities” panel at the 2013 Modern Languages Association (mla) Annual Convention. This panel, designed to provoke controversy and debate, succeeded in doing so. However, in order to create a more rigorous conversation focused on the many issues raised and elided and on the possibilities and limitations of digital humanities as they currently exist, we have produced this collaborative text. Common themes in Rhody’s and Chun’s responses are: the need to frame digital humanities within larger changes to university funding and structure, the importance of engaging with uncertainty and the ways in which digital humanities can elucidate “shadows” in the archive, and the need for and difficulty of creating alliances across diverse disciplines.  We hope that this text provokes more ruminations on the future of the university (rather than simply on the humanities) and leads to more wary, creative, and fruitful engagements with digital technologies that are increasingly shaping the ways and means by which we think.&nbsp