Numerous essential cellular processes, such as gene regulation and tRNA processing, are carried out by structured RNAs. While in vitro most RNAs become kinetically trapped in non-functional misfolded states that render them inactive on a biologically-relevant time scale, RNAs folding in vivo do not share this same outcome. RNAs do indeed misfold in the cell; however, chaperone proteins promote escape from these non-native states and foster folding to functional conformations. DEAD-box proteins are ATP-dependent RNA chaperone proteins that function by disrupting structure, which can facilitate structural conversions. Here, studies with both local and global focuses are used to uncover mechanistic features of DEAD-box proteins CYT-19 and Mss116p. Both of these proteins are general RNA chaperones as they each have the ability to facilitate proper folding of multiple structured RNAs. The first study probes how DEAD-box proteins interact with a simple duplex substrate. Separating the strands of a duplex is an ATP-dependent process and is central to structural disruption by DEAD-box proteins. Here, how ATP is utilized during duplex separation is monitored by comparing ATP hydrolysis rates with strand separation rates. Results indicate that one ATP molecule is sufficient for complete separation of a 6-11 base pair RNA duplex. Under some conditions, ATP binding in the absence of hydrolysis is sufficient for duplex separation. Next, focus is shifted to a more global perspective as the function of Mss116p is probed in the folding of a cognate group II intron substrate, aI5[gamma], under near-physiological conditions. Three catalytically-active constructs of aI5[gamma] are used and catalysis serves as a proxy for folding. Folding of all constructs is promoted by the presence of Mss116p and ATP. In vitro and in vivo results indicate that a local unfolding event is promoted by Mss116p, stimulating formation of the native state. Lastly, orthogonal methods that probe physical features of RNA are used to provide insight into the structural intermediates with which Mss116p acts. / text

No description available.

Photographic, film and video representations of dying and dead subjects bring to light delicate balancing acts of agency involving representational perspective. In this thesis, I examine contemporary, lens-based artworks by Sarah Charlesworth, Eric Fischl (whose sculptural medium is an exception), Alejandro Gonzalez Innaritu, Gillian Wearing, Andres Serrano, Nan Goldin, AA Bronson and Jorge Zontal, as well as works by photojournalists Richard Drew and Theresa Frare, to show how they effectively convey facets of identity to dying and dead subjects. The voice, visuality, touch and embodiment (in particular, the body's weight and its materiality) are considered dimensions of intersubjectivity in order to explore how they foster access to the dying or the dead. My hypothesis is that, despite the avenues of intersubjective agency that appear to be foreclosed to the dying and the dead, the artists negotiate the following, significant challenges: how to bear witness to suffering without enacting visual mastery; how to grant a voice to or engage in dialogue with a silenced subject; how to touch the other without inflicting injury. Through the artists' divergent representational paradigms, the terms of intersubjectivity will be shown to equally involve the potential for reverence as well as for representational violence and it is upon this duality that the ethical concern hinges. The degrees of photographic transparency invoked by the artists alter the emergence of identity and the extent to which it reflects the perspective of the dying and the dead or, alternatively, becomes a framework of distortion. In terms of subject matter, the causes of death to the subjects represented, all of which are non-fictional, are AIDS-related illness, falling from buildings and violence (sometimes self-inflicted). Conceptually, I will be relying upon the phenomenological models of Maurice Merleau-Ponty, the photographic theories of Roland Barthes, the feminist met

The majority of patients with chronic obstructive pulmonary disease (COPD) have milder airway obstruction and are not diagnosed in a timely fashion. Nevertheless, these patients are largely under-studied; this, despite new evidence of increased morbidity and mortality in this sub-population. Recent studies have highlighted the increased ventilatory requirements and abnormalities in respiratory mechanics as important features to explain the relatively reduced exercise tolerance and greater exertional dyspnea in these patients. However, it remains uncertain whether such abnormal mechanical factors actually limit exercise capacity in mild COPD. Accordingly, the objective of this study was to determine whether ventilatory constraints represent a primary factor in exercise limitation and increased dyspnea in this patient group. To determine the role of mechanical factors in exercise limitation in mild COPD, we selectively loaded the respiratory system by adding dead space (DS) to the breathing circuit. We compared ventilation, breathing pattern, operating lung volumes, and dyspnea intensity during incremental cycle exercise in 20 patients with GOLD stage I COPD (post-bronchodilator FEV1/FVC=61±5%, and FEV1=95±11% predicted; mean±SD) and 20 healthy age-, sex- and BMI-matched subjects under two conditions, in randomized order: unloaded control (CTRL) or ventilatory stimulation by 600mL of an added DS. Compared to the CTRL condition, both healthy and COPD participants had small decreases in peak work rate and no significant increase in peak ventilation with the added DS. At the highest equivalent work rate of 60 watts, DS caused a smaller increase in tidal volume (VT) in COPD compared with healthy subjects (+0.26±0.29 vs. +0.56±0.22 L respectively, p<0.01) with a correspondingly greater increase in dyspnea intensity (+1.8±1.8 vs. +0.2±0.6 Borg units, respectively, p<0.0001). At peak exercise, COPD patients failed to significantly increase VT, reflecting the fact that end-inspiratory lung volume (EILV) could not increase with DS vs. CTRL (5.25±0.91 vs. 5.16±0.84 L, respectively, p=0.41). This contrasts the results in health where EILV increased with DS vs. CTRL (5.40±1.01 vs. 5.13±0.90 L, respectively, p<0.05). We conclude that the lower exercise performance in mild COPD, compared with health, is explained by critical respiratory mechanical constraints which limit further increases in ventilation to support a higher metabolic load. / Thesis (Master, Physiology) -- Queen's University, 2012-09-28 12:04:50.507

The conversion of natural forests to production land uses has led to huge losses of biodiversity and continues to threaten remaining terrestrial flora and fauna throughout the world. The global demand for wood products and energy, which was partly responsible for the loss of primary native habitat, is now one of the leading drivers of afforestation with significant new areas of plantation replacing former agricultural lands. While plantations do not support the same biodiversity values as natural forests they do provide significant habitat for a range of species. Saproxylic invertebrates (species that are dependent on deadwood) are strongly affected by the temporal and spatial availability of different deadwood resources. Previous research on saproxylic invertebrates has largely been restricted to natural or managed natural forests predominantly in the Northern Hemisphere, where forest management practices have been modified to conserve these species This thesis fills a distinct research gap in New Zealand and is the first large scale study to quantify the effects of deadwood age, wood species, and landscape composition on saproxylic invertebrates in our plantation forests by direct rearing. In this thesis I show that thinning residues, which are currently retained in many plantation forests, provide significant habitat for a range of native invertebrate taxonomic groups, including diverse assemblages of Coleoptera and Hymenoptera. Deadwood age is an important attribute determining taxonomic richness of saproxylic invertebrates. Richness of invertebrate orders/classes and Coleoptera species all increased in older deadwood material, and a stepwise multidimensional analysis procedure indicated that the age of deadwood was the most important factor structuring saproxylic invertebrate community composition in Pinus radiata thinning residues. Deadwood age was a stronger predictor of community composition in thinning residue than measures of landscape composition, such as the proportion of remnant native forest cover. The change in saproxylic invertebrate composition that occurs with deadwood age was related to changes in the feeding guilds, with a transition from primary wood feeding species to predators/parasitoids and fungal feeders with increasing dead wood age. Because thinning’s are carried out at prescribed times throughout the stand rotation, stand age could be adopted as a proxy for deadwood age in these systems allowing forest managers a simple method for monitoring saproxylic beetle habitat availability . My research provides strong empirical evidence that supports the existing conservation paradigm that forest managers should seek to create a mosaic of habitats at the landscape scale to enhance biodiversity opportunities in plantations. In addition to the habitat opportunities provided by P. radiata deadwood that is derived from silvicultural practices there are several sources of native wood in plantations. Native woody resources are found in either the embedded remnant areas of native forest or in the understory of stands as many native woody species colonise this habitat. As yet the importance of native understory deadwood resources for saproxylic species is unknown. In addition it is unclear how the importance of such understory resources is influenced by proximity to remnant native forest patches. I used experimental wood billets of four tree species (3 native and the exotic P. radiata) placed along replicated transects spanning native habitat and adjacent early stage regenerating plantation stands to assess the saproxylic invertebrate assemblages associated with different deadwood species as a function of proximity to native forest. I found that an interaction between wood host specificity (local scale) and proximity to interior native forest (landscape scale) was the most important factor regulating saproxylic invertebrate community structure. Deadwood of the native subcanopy trees Schefflera digitata, Melicytus ramiflorus, Aristotelia serrata and the exotic conifer P. radiata provided habitat for different subsets of the saproxylic fauna. The most pronounced differences in saproxylic community structure were between the native sub-canopy broadleaf species and the exotic P. radiata. Surprisingly the P. radiata supported a greater species richness and abundance of saproxylic Coleoptera in native remnants than the native wood species in the same habitat. In general, species richness was higher in native forest habitats and declined with increasing distance from native habitat. These results suggest that both the diversity of deadwood resources that are available and their proximity to native remnants are important for maintaining saproxylic communities in plantations. However, two of the native wood species (M. ramiflorus and A. serrata) exhibited steep declines in species richness at the plantation native forest boundary, suggesting that the contrasting stand types (native remnant and young regenerating plantation stands) with their different microclimate may have had a significant influence. Future research needs to compare the saproxylic fauna of dead wood in mature plantation stands with adjacent native remnants to ascertain if the effect of native habitat proximity is due to landscape composition or a reflection of microclimatic differences. The large diversity of saproxylic species observed during this study highlights the importance of plantations as habitat for saproxylic species, particularly in heavily fragmented landscapes that retain little original native forest. My research findings provide forest managers with options for improving forest management to enhance opportunities for the conservation of saproxylic invertebrates. In addition my thesis provides one of the most comprehensive multi-taxon data sets of saproxylic species associated with a variety of deadwood resources. This information will be invaluable to future researchers that continue to work on New Zealand’s saproxylic fauna.

Abstract Titel: The Walking Gender Författare: Moa Linder Bakgrund: Den populära amerikanska TV-serien The Walking Dead är en zombiefiktion som  inbjuder människor världen över att följa seriens protagonister kämpandes mot zombies och mänskliga grupperingar i ett oroligt postapokalyptiskt USA. Serien kritiseras för att vara bakåtsträvande gällande dess representationer av genus och etnicitet och  det är vad denna analys ämnar att undersöka. Syfte: Syftet är att undersöka hur genus representeras genom karaktärerna i The Walking Dead med ett strukturalistiskt angreppssätt. Jag undersöker även vilken relation hudfärg har med genus i dessa representationer. Material/ metod: Mitt material består av två avsnitt av The Walking Dead. När jag analyserar valda karaktärer använder jag mig av en narrativ och semiotisk analys. Den narrativa analysmodellen ger en konkret struktur åt analysen som börjar med en övergripande narrativ beskrivning över avsnittet för att sedan gå in närmare i tre valda sekvenser som jag analyserar med hjälp av de semiotiska begreppen denotation och konnotation. Slutsatser/ resultat: Analysen visar på att genusrepresentationen hos karaktärerna i stort sker efter stereotypa mönster och anammar maskulina och feminina ideal där männen beskyddar och kvinnorna beskyddas. Det finns ett visst motstånd mot dessa mönster som främst visar sig i karaktären Michonne som inte följer feminina ideal utan istället bär stereotypa maskulina egenskaper. De svarta kvinnliga karaktärerna följer inte feminina ideal utan tendenserar att motsätta sig normen medan de vita kvinnliga karaktärerna upprätthåller feminina ideal. De manliga karaktärerna förkroppsligar det manliga idealet ’den riktiga mannen’. Den maskulina hegemonin verkar med en hierarkisk ordning där den asiatiske och den svarta manliga karaktären befinner sig lägre än de vita karaktärerna.

This research study analyses the construction of meaning surrounding the embalmed corpse in contemporary England. It documents a process of social change in which Legal, Medical and Religious discourses concerning the dead, once dominant and unchallenged, now co-exist, if somewhat uneasily, with modern constructions of death and the possibility of an after life. The meaning of the embalmed corpse is considered to be constructed by different elements which are presented historically. Initially religious discourses governed the meaning of the body, which was preserved for religious reasons. 17th century surgeon-embalmers requisitioned the corpse for reasons of status assertion, presenting their arguments in medical terms. Contemporary hygiene issues, in tandem with legal issues, today have a powerful impact on the corpse, which is usually experienced by mourners in the context of contemporary consumer culture, after the process of embalming has occurred. The decline of religious practices also mean that the contemporary corpse has assumed a far greater significance than in the past. From the perspective of the sociology of the body, based on the seminal work of Turner, this thesis discusses how changing experiences of live bodies are inextricably linked with changing experience of dead bodies in contemporary societies. This is accomplished through an interpretation of the different meaning attributed to embalmed corpses, together with an appreciation of the work of Hertz and Van Gennep, both of whom identified, in pre-literate societies, the centrality and embeddedness of the treatment of the corpse to funeral rituals. The thesis reports some empirical investigations of embalming-related issues which provide an analysis of contemporary meanings of the corpse and cast light upon the contemporary structure of the English funeral world. Embalmers expect to produce a culturally acceptable ‘death disguise’ for the benefit of mourners whose encounters with the corpse are surprisingly numerous in contemporary death-denying society. Culturally acceptable death images appear to focus upon the dead being in a condition of 'liminal repose', where the illusion of rest is constructed. Embalmers and funeral directors comprise occupations that are quite distinct, although working with the dead in different parts of the same process. Highlighting the significance of corpse appearance, whereby it is rendered 'normal', has also highlighted the socio-cultural process whereby this transformation occurs. As the dead are carefully re-presented, this has hidden the 'true' condition of the dead and therefore also hidden the covert technicians, embalmers, who accomplish this transformation. Embalming therefore appears a hidden aspect of the social construction of the dead, as death is now estranged from the popular context.

No description available.

This dissertation investigates ways in which early Jewish communities conceptualized the production and collection of writing. Through a study of 11QPsalms-a, the Qumran Psalms Scroll, it shows how modern book culture (shaped by the canon, codex, print, authorial copyright, and scholarly editing) has distorted our understanding of ancient texts and fostered anachronistic questions about their creation and reception. Taking seriously what early Jewish texts have to say about their own writtenness and building upon earlier scholarship on scriptural multiformity, the dissertation also uses theoretical insights from the field of Book History to study the identity, assembly, and literary context of the Psalms Scroll as an example of the ancient textual imagination. Physical and discursive evidence suggest that no concept of a “Book of Psalms” existed as a coherent entity in the ancient Jewish imagination, but that psalms collections were conceptualized and created in looser, unbounded ways. New metaphors made possible by electronic text, which likewise cannot be constrained into the categories of print book culture, can encourage new ways of imagining ancient concepts of fluid textuality as well. After a study of the status and compilation of the Psalms Scroll (Ch. 1-2), the dissertation engages the question of Davidic authorship (Ch. 3). David was not imagined as the author of a particular psalms collection, but as the inaugurator of a variety of liturgical traditions. The identity between an individual figure and a specific text should be unbound in favour of a looser relationship, allowing for the continuing growth of traditions inspired by the figure. Chapters 4 and 5 present a reading of the Psalms Scroll and Davidic lore alongside two other traditions: Ben Sira and angelic ascent literature. Both possess literary links with the Psalms Scroll, but also shed light on the ways in which ancient communities imagined writing and understood their own relationship to their texts. Thus, reading across canonical and generic boundaries embeds psalms traditions in a richer context of reception and provides a fuller picture of the ancient textual imagination. The conclusion makes a comparative gesture toward the Nachleben of psalms collecting in Syriac Christianity.

国立情報学研究所で電子化したコンテンツを使用している。