Life would not exist in the absence of catalysis. The “RNA World” model for the origin of life hinges on the capabilities of ribonucleic acid to encode information and perform catalysis (i.e. self-replication). Previously, functional nucleic acids such as ribozymes and deoxyribozymes (DNAzymes) have been isolated using the process of in vitro selection. This method is typically performed by isolating a catalytically active molecule from a large random library, with the assumption being that active molecules are already present in the pool and this method filters them from inactive molecules. However, in vitro selection has never been used to show that a molecule can be evolved from an inactive to an active catalyst. Here we show that the properties of DNA can be exploited to act as a proxy system for the origins of biotic chemistry by isolating a functional catalyst from a previously non-catalytic sequence. This project employs a novel perspective; rather than a random library, a known, non-functional sequence is utilized. Using in vitro selection, this known sequence is gradually evolved into a functional catalyst by solely allowing the existence of sequences that acquire mutations which enhance their function. Deep sequencing analysis of DNA pools along the evolution trajectory has identified individual mutations as the progressive drivers of molecular evolution. Evolving a catalyst from a non-catalyst gives insight into the comprehension of how life originated. This project demonstrates that an enzyme can indeed arise from a sequence of a functional polymer via permissive molecular evolution, a mechanism that may have been exploited by nature for the creation of the enormous repertoire of enzymes in the biological world today. / Thesis / Master of Science (MSc)

No description available.

The purpose of this thesis was to use color as the primary design element for a place of commerce along the Big Dig (Boston). Color informed the building form and provided the connection for the building type and the urban site. The thesis book unfolds in reverse order, with the intent to reveal the final design at the beginning. As the pages unfold, the evolution of the design emerges to complete with the beginning of the thesis. / Master of Architecture

The Sanskrit prātimokṣa-sūtras contained in the Gilgit Buddhist manuscripts have been identified as belonging to the Mūlasarvāstivāda school. However, the identification of these manuscripts as Mūlasarvāstivādin texts is problematic. A key factor for determining the school affiliation of a prātimokṣa is the rule order. The Gilgit prātimokṣa-sūtras, however, differ in their rule order. In this thesis, I explore the relationship of these Gilgit prātimokṣa-sūtras to Mūlasarvāstivādin literature. In order to do so, I have conducted a comparative analysis of the Gilgit prātimokṣa-sūtras focusing on differences in rule order in Gilgit Serials 2, 3a, and 4b/4c. I have also compared the rule order contained within the Gilgit prātimokṣa-sūtras to known Mūlasarvāstivādin commentaries. I argue that we have evidence for two distinct Mūlasarvāstivādin Vinaya traditions within the Gilgit prātimokṣa-sūtras. The author(s)/redactor(s) of Gilgit prātimokṣa-sūtras 2 and 3a were aware of a tradition similar, if not identical, to that known to the author(s)/redactor(s) of the Mūlasarvāstivādin prātimokṣa-sūtra contained in the Tibetan canon. Serial 4b/4c contains a different Mūlasarvāstivādin Vinaya tradition, one that has close parallels to Mūlasarvāstivādin commentaries. The Gilgit prātimokṣa-sūtras, therefore, contain Sanskrit evidence for multiple Mūlasarvāstivādin Vinaya traditions. / Master of Arts (MA)

The lowland Maya site of Ceibal, Guatemala, had a long history of occupation, spanning from the Middle Preclassic Period through the Terminal Classic (1000 BC to AD 950). The Ceibal-Petexbatun Archaeological Project has been conducting archaeological investigations at this site since 2005 and has obtained 154 radiocarbon dates, which represent the largest collection of radiocarbon assays from a single Maya site. The Bayesian analysis of these dates, combined with a detailed study of ceramics, allowed us to develop a high-precision chronology for Ceibal. Through this chronology, we traced the trajectories of the Preclassic collapse around AD 150–300 and the Classic collapse around AD 800–950, revealing similar patterns in the two cases. Social instability started with the intensification of warfare around 75 BC and AD 735, respectively, followed by the fall of multiple centers across the Maya lowlands around AD 150 and 810. The population of Ceibal persisted for some time in both cases, but the center eventually experienced major decline around AD 300 and 900. Despite these similarities in their diachronic trajectories, the outcomes of these collapses were different, with the former associated with the development of dynasties centered on divine rulership and the latter leading to their downfalls. The Ceibal dynasty emerged during the period of low population after the Preclassic collapse, suggesting that this dynasty was placed under the influence from, or by the direct intervention of, an external power.

Historians have debated to what extent the free people of color in New Orleans were members of a wealthy privileged elite or part of a middle or working class in the South's largest antebellum city. This study steps outside the debate to suggest that analysis of the censuses of 1850 and 1860 shows correlations between neighborhoods, household structures, and occupations that reveal a heterogeneous population that eludes simple definitions. In particular this study focuses on mixed-race households to shed light on this segment of the free colored population that is mostly unstudied and generally misrepresented. This study also finds that immediately prior to the Civil War, mixed-race families, for no easily understood reason, tended to cluster in certain neighborhoods. Mostly this study points out that by the Civil War, the free people of color in New Orleans had evolved into a diverse mostly working class population.

L'infertilité affecte près d'un couple sur 6 en France. L’obésité et l'excès de réserves adipeuses, à l'origine de stress oxydant, sont associés à l'infertilité idiopathique. L’équilibre des concentrations entre les pro et antioxydants est assuré par des enzymes antioxydantes, dont la fonction est partiellement contrôlée par des polymorphismes génétiques. De plus, l'altération des gamètes par le stress oxydant pourrait aussi entraîner des conséquences sur le développement d'infertilité chez la descendance. L'objectif de cette étude était d’évaluer les relations entre l’alimentation, le stress oxydant et l’infertilité à travers une étude cas-témoins chez l’Homme et à l’aide d’un modèle animal. Chez l’Homme, le polymorphisme des enzymes impliquées dans le stress oxydant a été étudié chez 110 individus infertiles et 69 fertiles. Le risque d’infertilité est augmenté chez les hommes porteurs d’au moins un allèle Ala-SOD2 (rs4880) et chez les porteurs, hommes et femmes confondus, de deux allèles G-NOS3 (rs1799983). La prise en compte de ces polymorphismes pourrait permettre d’adapter l’alimentation et/ou la prise d’antioxydants selon le génotype du couple infertile idiopathique. Chez la lapine, une alimentation hyperlipidique administrée dès la période prépubertaire a un impact délétère sur la folliculogénèse avec une réduction du nombre de follicules tertiaires et une atrésie folliculaire augmentée par rapport aux témoins. La fonction de l’axe hypothalamo-hypophysaire est aussi perturbée. Chez les descendantes, on observe une atrésie folliculaire augmentée. Ces résultats indiquent qu'une alimentation déséquilibrée en lipides entraine des dysfonctions de l’axe hypothalamo-hypophyso-gonadique chez la mère et ses filles. / Infertility affects one in 6 couples. Obesity and excess fat, which induce oxidative stress, have been associated with idiopathic infertility. The balance between pro- and antioxidant enzymes is insured by antioxidant enzymes, which activity partly depends on genetic polymorphisms. Moreover, the alteration of gamete quality through oxidative stress may also affect offspring development and fertility. The aim of the project was to evaluate the association between nutrition, oxidative stress and infertility through a case-control study in humans and using a rabbit model. In humans, the genetic polymorphism of enzymes involved in oxidative stress was studied in 110 infertile and 69 fertile individuals. The presence of at least one Ala-SOD2 allele in men and the presence of two G-NOS3 alleles in both men and women increased the risk of infertility. The analysis of these gene polymorphisms in infertile couples may help adapting nutrition and/or antioxidant intake depending on the couple's genotype. Feeding a hyperlipidic diet to female rabbits from the prepubertal period has a detrimental impact on folliculogenesis, with a reduction in tertiary follicles and an increase in atretic follicles numbers in the ovary, together with an alteration of the hypothalamo-pituitary axis. An increased number of atretic follicles was also observed in adult female offspring. Those results highlight the importance of a high fat diet on hypothalamo-pituitary-gonadal function in females and their offspring.

No description available.

From what wells did the apocalyptic writers draw? What motivated them to write such bizarre and fantastic stories about the future end of history and battles between the forces of good and the forces of evil? The Book of Daniel is considered the first and only apocalypse of the Hebrew Bible, and it was the primary inspiration for much of the Book of Revelation, Apocalypse of John in the Christian New Testament. But well before Daniel, apocalyptic passages appeared in Jewish literature. With the discovery of the Dead Sea Scrolls in 1947 came also the discovery of the oldest Jewish apocalypse, written in ancient Aramaic, and well-known in both ancient Judaism and early Christianity: a collection of books known as 1 Enoch. It was in these texts, especially the first and oldest one, the Book of Watchers, that apocalyptic imagery, including the Son of Man figure, first appeared in Jewish writing. Though scholars note developments from the Hebrew Prophets, particularly the Latter ones, a significant evolution took place. The question is why and when? My thesis is that the earliest Jewish apocalyptic writing, the Book of Watchers, 1 Enoch 1-36, was written as a result of Babylonian elements. With the help of scholars specializing in Jewish apocalyptic origins, I hope to show hoe the roots of this fascinating aspect of religion, which captivates and often frightens twenty-first century humans, took hold twenty-five hundred years ago in Mesopotamia.

<p>Primates and many other animals that move in an arboreal environment often cling, sometimes for long periods, on vertical supports. Primates, however, face a special challenge in that almost all primates bear nails on the tips of their digits rather than claws. Squirrels and other arboreal animals possess claws and/or adhesive pads on their digits in order to hold their weight on vertical substrates. Assuming the ancestral primate was arboreal and lost claws prior to the radiation of primates this paradox has important implications and raises a significant question about living primates and early primate evolution: how can primates maintain vertical postures without claws and how did early primates meet this challenge? Primate vertically clinging and grasping postures (VCG) have been studied in the wild and theoretical models of VCG postures have been described. This dissertation builds on this work, by studying the biomechanics of VCG postures in primates. Based on mechanical models, it was hypothesized VCG posture in primates will vary in three ways. </p><p>Hypothesis 1: Species with different morphological features associated with different locomotor modes will vertically cling and grasp in different ways. </p><p>Hypothesis 2: As substrate size increases, primates will place their arms to the side of the support and adjust posture and muscle recruitment in order to maintain a necessary tangential to normal force ratio to resist gravity. </p><p>Hypothesis 3: On substrates of the same relative size, larger animals should be less effective at maintaining VCG postures due to scaling relationships between muscle strength and body mass. </p><p>The sample consisted of multiple individuals from eight strepsirrhine species at the Duke Lemur Center. The sample varied in locomotor mode--habitual vertical clinging and leaping (VCL) compared to less specialized arboreal quadrupeds--and body mass--100 to 4,000 grams. Subjects were videorecorded while holding VCG postures on substrates of increasing size. Substrate preference data were calculated based on frequency and duration of VCG postures on each substrate. Qualitative kinematic data were recorded for a maximum of thirty trials per individual, per substrate. Angular data were calculated for forelimbs and hindlimbs from these videos for ten trials per individual per substrate. In addition, kinetic data from an imbedded force transducer were collected for two species that vary in locomotor mode, but not body mass. </p><p>There are several significant and relevant results from this study that address both primate functional anatomy and locomotor evolution. Hypothesis one was supported by hand and hindlimb joint postures, shown to be highly sensitive to locomotor mode. VCL primates exhibited deeply flexed limbs and more hand grasping (wrapping around the substrate) versus parallel hand postures and use of bowed finger postures compared to less specialized primates. Kinetically, species were shown to bear the majority of their weight in their hindlimbs relative to their forelimbs. The forelimb joints and foot showed little variation by habitual locomotor mode. Hypothesis two found support in that species tend to prefer smaller substrates, clinging less frequently for shorter durations as substrate size increases. Hand posture changed as size increased, as primates (except for the slow lorises) in this study grasped with their pollex on smaller substrates, but the pollex disengaged in grasping on larger substrates. Hypothesis three was not supported; body mass did not influence VCG postures. </p><p>Taken together, the finding that the forelimb held a wide range of postures on each substrate size for all species and played a limited role in weight-bearing suggests the forelimb free to move (to adjust posture and or forage). The hindlimb plays a more specific role in weight-bearing and is more sensitive to variations in primate anatomy. Additionally, these findings lead to hypotheses concerning the relatively short pollexes of primates, and that the ancestral primate was smaller than 100g and preferred small substrates as found in a fine-branch niche.</p> / Dissertation