256 resultados para Plateaus


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Abstract (Re)thinking Bodies: Deleuze and Guattari 's becoming-woman seeks to explore the notion of becoming-woman, as put forth by Gilles Deleuze and Felix Guattari in their collaborative 1982 text, A Thousand Plateaus: Capitalism and Schizophrenia, and as received by such prominent feminist theorists as Rosi Braidotti and Elizabeth Grosz. Arguing that the fairly decisive repudiation of this concept by some feminist theorists has been based on a critical misunderstanding, this project endeavors to clarify becomingwoman by exploring various conceptions of the body put forth by Baruch de Spinoza, Friedrich Nietzsche and Simone de Beauvoir. These conceptions of the body are indispensible to an appreciation of Deleuze and Guattari's notion of a body lived on both an immanent and transcendent plane, which, in turn, is indispensable to an appreciation of the concept of becoming (and, in particular, the concept of becoming-woman) as intended by Deleuze and Guattari.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This thesis uses a multifaceted process to engage with the topic of food sovereignty in California. It employs diverse methods, including critical and creative prose, photography, autoethnographic mixed media, storytelling and poetry. I am particularly concerned with the " " challenges of approaching food sovereignty, a radical praxis that combines subsistence practices with anti-capitalist resistance, while in my own "skin," which is thoroughly embedded in white, urban, middle classed culture and in corltextualizing ecological relationshipslkinships via cultural, historical and economic trajectories. The project utilizes a processual methodlology drawing substantially from the work of Brian Massumi to explore these issues through four creative narrative pieces which coalesce around the elemental metaphors of air, fire, water and earth. Following Deleuze and Guatarri's concept ofrhizomatic plateaus, the thesis narratives are comprised of many non-hierarchical layers and can be read from many angles. Each is offered "in process" rather than as a finished piece, thus practically validating the concept of the ongoing work of research and suggesting the equally omnipresent possibility of change and mutation in the formation relationally based knowledges. Cultivating ecological ethic and healing on multisensory levels, as well as commitment to emergent and re-productivist worldviews are goals of this project's research.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

L’ostéoarthrose (OA) est une pathologie qui touche les articulations principalement chez les personnes âgées. Il devient capital de mieux cerner cette pathologie à cause des coûts économiques qu’elle engendre mais surtout à cause du vieillissement de la population. Cette maladie se caractérise par une dégradation du cartilage articulaire, une sclérose osseuse, une inflammation de la membrane synoviale ainsi que la présence d’ostéophytes. L’étiologie de cette pathologie est restée nébuleuse car la recherche sur la maladie touchait principalement le cartilage articulaire. Toutefois, le rôle clé de l’os sous-chondral dans l’OA est maintenant reconnu. L’obésité étant un facteur de risque de l’OA, nous avons émis l’hypothèse que la leptine, une adipocytokine clé dans l’obésité, joue un rôle important dans l’OA. En effet, la leptine modifie le phénotype des ostéoblastes (Ob) normaux humain et puisque les Ob OA humains ont un phénotype altéré, notre objectif était de déterminer le rôle potentiel de la leptine dans ces cellules. Pour ce faire, nous avons préparé des cultures primaires d’Ob issus de la plaque sous-chondral du plateau tibial de patients OA et d’individus normaux (N). L’expression de la leptine et de son récepteur actif (OB-Rb) ont été mesurées par RT-PCR en temps réel, et leur production a été mesurée par ELISA et immunobuvardage (IB). La prolifération des Ob OA a été déterminée par incorporation de BrdU. La phosphorylation de p42/44 MAPK dans les Ob OA a été déterminée par IB. Le phénotype des Ob fut déterminé par la mesure de l’activité de la phosphatase alcaline (ALP) et la sécrétion d’ostéocalcine (OC), en présence ou non de leptine. De plus, les effets des ARNs d’interférences (SiRNA) anti-leptine et anti OB-Rb sur le phénotype des Ob OA furent déterminés via leur impact sur l’activité de l’ALP et sur la sécrétion d’OC. L’effet dose-réponse de la leptine sur les expressions d’OB-Rb, du facteur de croissance TGF-1 ou encore sur sa propre expression furent déterminées par RT-PCR en temps réel. Pour terminer, la signalisation de la leptine a été étudiée en évaluant l’effet dose réponse de celle-ci sur la production des protéines JAK2 et STAT3 phosphorylées par IB. Les résultats obtenus ont montrés que les Ob OA expriment et produisent plus de leptine que les Ob N. Au niveau phénotypique, ces Ob OA possèdent une activité de l’ALP ainsi qu’une sécrétion d’OC plus importante que celles observées chez les Ob N. L’ajout d’anticorps inactivant l’interaction leptine et OB-Rb ou d’inhibiteurs chimiques comme tyrphostin ou piceatannol diminuèrent l’activité de l’ALP ainsi que la sécrétion d’OC dans les Ob OA. Par contre, l’ajout de leptine exogène aux Ob OA augmenta l’activité de l’ALP sans pour autant faire varier la sécrétion d’OC. La leptine à des doses de 1ng/ml à 10mg/ml stimula la prolifération des Ob OA ainsi que la phosphorylation de p42/44 MAPK. La leptine exogène diminua l’expression de TFG-1 tandis qu’elle stimula la phosphorylation de JAK2 et STAT3 ou encore sa propre expression de manière dose-dépendante. Cependant, l’expression d’OB-Rb diminua de manière dose-dépendante. Enfin, le traitement des Ob OA avec des Si leptine ou Si OB-Rb diminua l’activité d’ALP, la sécrétion d’OC, l’expression de la leptine, l’expression d’OB-RB ainsi que l’expression du facteur TGF-1. L’ensemble de ces données démontre que la leptine endogène des Ob OA est sous contrôle des facteurs de croissance et qu’elle contribue à maintenir le phénotype anormal de l’os sous-chondral OA. De plus, ceci suggère que la leptine serait un acteur important dans la régulation du remodelage osseux.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

La vitamine E (VE) est parfois préconisée pour le traitement de l’arthrose chez le chien, par contre aucune étude n’a documenté cette efficacité. L’objectif de cette étude était de déterminer l’effet d’une forte dose de VE alimentaire sur l’inflammation et la douleur arthrosique chez le chien. Deux groupes de chiens avec arthrose provoquée par section du ligament croisé crânial du membre postérieur droit ; un groupe contrôle (n=8) et un groupe supplémenté avec la VE (n=7), ont été suivis selon un design parallèle, randomisé et en aveugle. La supplémentation a été commencée 1 jour après la chirurgie avec une dose de 400 UI/animal/jour par voie orale pendant 56 jours. Les évaluations objectives (activité électrodermique, EDA) et subjectives (VAS, NRS) de la douleur ont été faites avant la chirurgie J0, à J28 et à J55 après chirurgie. La détermination de la concentration synoviale des marqueurs de l’inflammation (IL-1β, PGE2 et NOx) et l’étude lésionnelle ont été faites après l’euthanasie à J56. Une comparaison unilatérale avec un seuil alpha de 10% a été réalisée. Les concentrations synoviales de PGE2 et de NOx étaient faibles chez le groupe supplémenté en VE par rapport au contrôle (P=0,03 et P<0,0001 respectivement). Les valeurs de VAS, NRS et EDA ont montré une tendance constante à l’amélioration de la douleur dans le groupe traité, avec des résultats significatifs obtenus pour VAS à J55 et pour EDA à J28 (P ajusté = 0,07 dans les deux cas). L’analyse histologique du cartilage articulaire a montré une réduction significative des scores lésionnels dans le groupe traité. C’est la première fois qu’une étude menée chez le chien avec arthrose, a montré qu’une forte dose en VE alimentaire permet de réduire les marqueurs de l’inflammation articulaire, les lésions histologiques cartilagineuses et permet aussi d’améliorer les signes de la douleur associe à l’arthrose.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Ce petit échantillon d’une étude ethnographique, fait à partir de la méthode d’observation participante, interroge la nature de la tendance de la mode auprès de jeunes citadins au coeur d'un centre urbain francophone du Canada. Les participants identifient un « look » comme étant emblématique du Plateau, un arrondissement de Montréal qui est démographiquement divers et contenant beaucoup de commerces dynamiques. Le Plateau a été promu par les organisations de la ville de Montréal comme le point central de la mode, arts et culture. Locaux ou simples touristes voient le Plateau comme un environnement aidant à la transformation personnelle et à l’autoréalisation, particulièrement chez les locaux de 18-30 ans. Plus particulièrement, les membres appartenant à cette tranche d’âge conçoivent leurs propres interprétations de la mode et participent à un certains nombres de projets créatifs en vue de réaliser d’authentiques et véritables expressions de soi. Cependant, à cause de la commercialisation de la mode présentée pour les consommateurs du Plateau, la jeune population perçoit le courant dominant du « hipster » comme n’étant plus l’authentique représentation à leur course à l’authenticité individuelle dans un monde en perpétuel globalisation. La chercheuse a découvert l’existence d’une idéologie de l’individu restreint à ce quartier. Vu l’animosité présente parmi la population locale du Plateau pour le courant principal hipster, l’ensemble de ces données montrent qu’il y a un besoin d’une meilleure compréhension de la relation entre la commercialisation de la mode occidentale et de ces acheteurs au niveau de l’individu et au niveau local dans les espaces urbaine en perpétuel globalisation. Le contexte de la mode dans cet environnement est contraint par l’hypothèse de la valeur qu'être différent est imaginé et digne d’intérêt dans cette communauté si et seulement si quelqu’un est confiant au point de se tenir debout avec ses idéaux au milieu des autres.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Within the noncollinear local spin-density approximation, we have studied the ground state structure of a parabolically confined quantum wire submitted to an in-plane magnetic field, including both Rashba and Dresselhaus spin-orbit interactions. We have explored a wide range of linear electronic densities in the weak (strong) coupling regimes that appear when the ratio of spin-orbit to confining energy is small (large). These results are used to obtain the conductance of the wire. In the strong coupling limit, the interplay between the applied magnetic field¿irrespective of the in-plane direction, the exchange-correlation energy, and the spin-orbit energy-produces anomalous plateaus in the conductance vs linear density plots that are otherwise absent, or washes out plateaus that appear when the exchange-correlation energy is not taken into account.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Die Ionisation von H2 in intensiven Laserpulsen wird mit Hilfe der numerischen Integration der zeitabhängigen Schrödingergleichung für ein Einelektronenmodell untersucht, das die Vibrationsbewegung berücksichtigt. Die Spektren der kinetischen Elektronenenergie hängen stark von der Vibrationsquantenzahl des erzeugten H2+ Ions ab. Für bestimmte Vibrationszustände ist die Ausbeute der Elektronen in der Mitte des Plateaus stark erhöht. Der Effekt wird "channel closings" zugeschrieben, die in Atomen durch Variation der Laserintensität beobachtet wurden. The ionization of H2 in intense laser pulses is studied by numerical integration of the time-dependent Schrödinger equation for a single-active-electron model including the vibrational motion. The electron kinetic energy spectra in high-order above-threshold ionization are strongly dependent on the vibrational quantum number of the created H2+ ion. For certain vibrational states, the electron yield in the mid-plateau region is strongly enhanced. The effect is attributed to channel closings, which were previously observed in atoms by varying the laser intensity.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Die vorliegende Arbeit beschäftigt sich mit dem Werk des französischen Philosophen Gilles Deleuze (1925-1995), indem sie dessen vielfältig-pluralistisches, in mancher Hinsicht sogar heterogenes Denken in einen Zusammenhang mit vitalistischen Philosophien der ersten Hälfte des 20. Jahrhunderts stellt (an erster Stelle Henri Bergson, aber auch Hans Driesch und Jakob von Uexküll), um auf diese Weise – durch Vergleiche und Gegenüberstellungen - zu verdeutlichen, dass und inwiefern der Vitalismus in der Version von Deleuze unter dem Eindruck der Entwicklung der Biologie seit Darwin (für die hier besonders die wissenschaftsphilosophischen Überlegungen der französischen Molekularbiologen François Jacob und Jacques Monod herangezogen werden) nicht mehr in erster Linie naturphilosophisch verstanden werden kann, sondern experimentell. Das, womit hier gedanklich experimentiert wird, sind Intensitäten. Und Intensität – so wird dargelegt – ist der Schlüsselbegriff zum Verständnis von Deleuzes’ erstem philosophischen Hauptwerk „Differenz und Wiederholung“. Im Zeichen eines Denkens der Intensitäten versucht Deleuze etablierte Dualismen wie die von Natur (physis) und Kunst (techné), Mensch und Tier, Individualität und Allgemeinheit zu unterlaufen. Weil dieser Versuch sich selbst als ein – wie es in dem von Deleuze gemeinsam mit dem Psychiater Félix Guattari verfassten Buch „Tausend Plateaus“ heißt - Vorstoß in "eine Welt aus formlosen, gegenstandslosen und gesichtslosen Schnelligkeiten und Langsamkeiten" versteht, stellt sich mit der Frage nach den lebenspraktischen Aspekten dieses grenzüberschreitenden und Freiräume eröffnenden Vorhabens auch die nach den damit verbundenen Risiken und Nebenwirkungen. Zur Konkretisierung werden Beispiele aus der modernen Literatur (die Verzeitlichung des Denkens bei Marcel Proust, aber auch die existentielle Sprachskepsis Antonin Artauds), der bildenden Kunst (die Deformationskunst in der Malerei Francis Bacons) und der Moral- bzw. moralkritischen Philosophie (der Stoizismus als eine Art Kunst der Selbstverteidigung, Nietzsches Umwertung aller Werte als eine Kunst der Selbstüberbietung) erörtert. Was in diesen Praktiken stattfindet und zum Ausdruck gebracht wird, sind Zerreißproben, d. h. radikale Belastungen oder Erprobungen von Vermögen wie Sinnlichkeit, Einbildungskraft, Denken, weshalb diese Versuche mit Deleuze, der sich hier von den stilpsychologischen Untersuchungen des Kunsthistorikers Wilhelm Worringer hat inspirieren lassen, als Spielarten eines nichtorganischen Lebens zu verstehen sind. Sich darauf in einem ständigen Wechsel von Annäherung und Distanzierung einzulassen, macht das ausgeprägte Pathos der Philosophie aus, auf das man im Denken von Gilles Deleuze trifft.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Short summary: This study was undertaken to assess the diversity of plant resources utilized by the local population in south-western Madagascar, the social, ecological and biophysical conditions that drive their uses and availability, and possible alternative strategies for their sustainable use in the region. The study region, ‘Mahafaly region’, located in south-western Madagascar, is one of the country’s most economically, educationally and climatically disadvantaged regions. With an arid steppe climate, the agricultural production is limited by low water availability and a low level of soil nutrients and soil organic carbon. The region comprises the recently extended Tsimanampetsotsa National Park, with numerous sacred and communities forests, which are threatened by slash and burn agriculture and overexploitation of forests resources. The present study analyzed the availability of wild yams and medicinal plants, and their importance for the livelihood of the local population in this region. An ethnobotanical survey was conducted recording the diversity, local knowledge and use of wild yams and medicinal plants utilized by the local communities in five villages in the Mahafaly region. 250 households were randomly selected followed by semi-structured interviews on the socio-economic characteristics of the households. Data allowed us to characterize sociocultural and socioeconomic factors that determine the local use of wild yams and medicinal plants, and to identify their role in the livelihoods of local people. Species-environment relationships and the current spatial distribution of the wild yams were investigated and predicted using ordination methods and a niche based habitat modelling approach. Species response curves along edaphic gradients allowed us to understand the species requirements on habitat conditions. We thus investigated various alternative methods to enhance the wild yam regeneration for their local conservation and their sustainable use in the Mahafaly region. Altogether, six species of wild yams and a total of 214 medicinal plants species from 68 families and 163 genera were identified in the study region. Results of the cluster and discriminant analysis indicated a clear pattern on resource, resulted in two groups of household and characterized by differences in livestock numbers, off-farm activities, agricultural land and harvests. A generalized linear model highlighted that economic factors significantly affect the collection intensity of wild yams, while the use of medicinal plants depends to a higher degree on socio-cultural factors. The gradient analysis on the distribution of the wild yam species revealed a clear pattern for species habitats. Species models based on NPMR (Nonparametric Multiplicative Regression analysis) indicated the importance of vegetation structure, human interventions, and soil characteristics to determine wild yam species distribution. The prediction of the current availability of wild yam resources showed that abundant wild yam resources are scarce and face high harvest intensity. Experiments on yams cultivation revealed that germination of seeds was enhanced by using pre-germination treatments before planting, vegetative regeneration performed better with the upper part of the tubers (corms) rather than the sets of tubers. In-situ regeneration was possible for the upper parts of the wild tubers but the success depended significantly on the type of soil. The use of manure (10-20 t ha¹) increased the yield of the D. alata and D. alatipes by 40%. We thus suggest the promotion of other cultivated varieties of D. alata found regions neighbouring as the Mahafaly Plateau.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Human selenium (Se) requirements are currently based on biochemical markers of Se status. In rats, tissue glutathione peroxidase-1 (Gpx1) mRNA levels can be used effectively to determine Se requirements; blood Gpx1 mRNA levels decrease in Se-deficient rats, so molecular biology-based markers have potential for human nutrition assessment. To study the efficacy of molecular biology markers for assessing Se status in humans, we conducted a longitudinal study on 39 subjects (age 45 +/- 11) in Reading, UK. Diet diaries (5 day) and blood were obtained from each subject at 2, 8, 17 and 23 weeks, and plasma Se, glutathione peroxidase (Gpx3) enzyme activity, and selenoprotein mRNA levels were determined. There were no significant longitudinal effects on Se biomarkers. Se intake averaged 48 +/- 14 mu g/d. Plasma Se concentrations averaged 1.13 +/- 0.16 mu mol/l. Plasma Se v. energy-corrected Se intake (ng Se/kJ/d) was significantly correlated, but neither Gpx3 activity v. Se intake (ng Se/kJ/d) nor Gpx3 activity v. plasma Se was significantly correlated. Collectively, this indicates that subjects were on the plateaus of the response curves. Selenoprotein mRNAs were quantitated in total RNA isolated from whole blood, but mRNA levels for Gpx1, selenoprotein H, and selenoprotein W (all highly regulated by Se in rodents), as well selenoprotein P, Gpx3, and phospholipid hydroperoxide glutathione peroxidase were also not significantly correlated with plasma Se. Thus selenoprotein molecular biomarkers, as well as traditional biochemical markers, are unable to further distinguish differences in Se status in these Se replete subjects. The efficacy of molecular biomarkers to detect Se deficiency needs to be tested in Se-deficient populations.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Mako bimodal volcanic belt of the Kedougou-Kenieba inlier is composed of volcanic basalts and peridotites interbedded by quartzites and limestones intruded by different generations of granitoids. The early volcanic episode of the belt is constituted of submarine basalts with peridotite similar to those of the oceanic abyssal plains. It is intruded by the Badon Kakadian TTG-granitic batholite dated around 2200 Ma. The second volcanic phase is constituted of basaltic, andesitic, and felsitic flows exhibit structures of aerial volcanic rocks. It is intruded by granites dated between 2160 and 2070 Ma. The general pattern of trace element variation of submarine volcanic rocks is consistent with those of basalts from oceanic plateaus which are the modern equivalent of the Archean greenstones belts. The Nd and Sr isotopic systematics typical of juvenile material indicates that the source of these igneous rocks is derived from a depleted mantle source. These results are consistent with the idea of a major accretion within the West African Craton occurring at about 2.1 Ga and corresponding to an important process of mantle-oceanic lithosphere differentiation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this paper I argue for the use of Deleuzian theories in educational contexts. In particular, I am interested in the use of the concept of rhizomes, and the analysis of texts as rhizomes, drawing on Deleuze and Guattari's work in A Thousand Plateaus (1987). I discuss the possibilities for using rhizomatics in educational contexts through an exploration of the construction of an 'apparatus of social critique' (Buchanan, 2000). I then describe a rhizomatic understanding of the relationships between teachers and policy texts, which can disrupt commonsense understandings of these relations. I provide examples from my own research (Honan, 2001) of a rhizo-textual analysis of policy texts. This rhizo-textual analysis involved an exploration of the construction of the subject position, teacher, within one policy text, as well as a mapping of two teachers' readings of this text. The paper concludes with a discussion of the implications for using Deleuzian theory in educational contexts, implications for both policy developers and educational researchers.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A single-factor experiment was conducted to investigate the effects of dietary astaxanthin concentration on the skin colour of snapper. Snapper (mean weight=129 g) were held in white cages and fed one of seven dietary levels of unesterified astaxanthin (0, 13, 26, 39, 52, 65 or 78 mg astaxanthin kg−1) for 63 days. Treatments comprised four replicate cages, each containing five fish. The skin colour of all fish was quantified using the CIE L*, a*, b* colour scale after 21, 42 and 63 days. In addition, total carotenoid concentrations of the skin of two fish cage−1 were determined after 63 days. Supplementing diets with astaxanthin strongly affected redness (a*) and yellowness (b*) values of the skin at all sampling times. After 21 days, the a* values increased linearly as the dietary astaxanthin concentration was increased before a plateau was attained between 39 and 78 mg kg−1. The b* values similarly increased above basal levels in all astaxanthin diets. By 42 days, a* and b* values increased in magnitude while a plateau remained between 39 and 78 mg kg−1. After 63 days, there were no further increases in measured colour values, suggesting that maximum pigmentation was imparted in the skin of snapper fed diets >39 mg kg−1 after 42 days. Similarly, there were no differences in total carotenoid concentrations of the skin of snapper fed diets >39 mg kg−1 after 63 days. The plateaus that occurred in a* and b* values, while still increasing in magnitude between 21 and 42 days, indicate that the rate of astaxanthin deposition in snapper is limited and astaxanthin in diets containing >39 mg astaxanthin kg−1 is not efficiently utilized. Astaxanthin retention after 63 days was greatest from the 13 mg kg−1 diet; however, skin pigmentation was not adequate. An astaxanthin concentration of 39 mg kg−1 provided the second greatest retention in the skin while obtaining maximum pigmentation. To efficiently maximize skin pigmentation, snapper growers should commence feeding diets containing a minimum of 39 mg unesterified astaxanthin kg−1 at least 42 days before sale.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

One of the fundamental machine learning tasks is that of predictive classification. Given that organisations collect an ever increasing amount of data, predictive classification methods must be able to effectively and efficiently handle large amounts of data. However, it is understood that present requirements push existing algorithms to, and sometimes beyond, their limits since many classification prediction algorithms were designed when currently common data set sizes were beyond imagination. This has led to a significant amount of research into ways of making classification learning algorithms more effective and efficient. Although substantial progress has been made, a number of key questions have not been answered. This dissertation investigates two of these key questions. The first is whether different types of algorithms to those currently employed are required when using large data sets. This is answered by analysis of the way in which the bias plus variance decomposition of predictive classification error changes as training set size is increased. Experiments find that larger training sets require different types of algorithms to those currently used. Some insight into the characteristics of suitable algorithms is provided, and this may provide some direction for the development of future classification prediction algorithms which are specifically designed for use with large data sets. The second question investigated is that of the role of sampling in machine learning with large data sets. Sampling has long been used as a means of avoiding the need to scale up algorithms to suit the size of the data set by scaling down the size of the data sets to suit the algorithm. However, the costs of performing sampling have not been widely explored. Two popular sampling methods are compared with learning from all available data in terms of predictive accuracy, model complexity, and execution time. The comparison shows that sub-sampling generally products models with accuracy close to, and sometimes greater than, that obtainable from learning with all available data. This result suggests that it may be possible to develop algorithms that take advantage of the sub-sampling methodology to reduce the time required to infer a model while sacrificing little if any accuracy. Methods of improving effective and efficient learning via sampling are also investigated, and now sampling methodologies proposed. These methodologies include using a varying-proportion of instances to determine the next inference step and using a statistical calculation at each inference step to determine sufficient sample size. Experiments show that using a statistical calculation of sample size can not only substantially reduce execution time but can do so with only a small loss, and occasional gain, in accuracy. One of the common uses of sampling is in the construction of learning curves. Learning curves are often used to attempt to determine the optimal training size which will maximally reduce execution time while nut being detrimental to accuracy. An analysis of the performance of methods for detection of convergence of learning curves is performed, with the focus of the analysis on methods that calculate the gradient, of the tangent to the curve. Given that such methods can be susceptible to local accuracy plateaus, an investigation into the frequency of local plateaus is also performed. It is shown that local accuracy plateaus are a common occurrence, and that ensuring a small loss of accuracy often results in greater computational cost than learning from all available data. These results cast doubt over the applicability of gradient of tangent methods for detecting convergence, and of the viability of learning curves for reducing execution time in general.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The thesis concerns the treatment of actuality in film and television, particularly the narrativization of actuality images, and the context of their placement within audio/visual texts. Several instances of the convergence of media form and genre are analyzed, and the conventions of classificatory systems and boundaries that pertain to film and television representations are reconsidered in light of changes in the conventions of genre. The distinction between, and convergence of fictional and non-fictional conventions of narrative are therefore central to the thesis, as are the related issues of viewer response, the nature of subjectivity in the viewer, the connectivity of text and culture, and the relations of actuality to the text. The thesis traces the narrativization of actuality through textual, formal and genre boundaries, adopting a ‘line of flight or deterritorialization’ that enables the thesis to ‘change in nature and connect with other multiplicities.’This line of flight passes through the conventional separation of genre groupings and texts, and, similarly, has been applied in the thesis as a rationale for the diminution of theoretical boundaries. A multiperpectival approach is applied to the permeability of, or transcendent relations of the analysis to the boundaries between genres, between texts and culture, and between actuality and virtual representation. In the thesis there is also a theoretical deterritorialization that consents to a pluralism of theory, which is an approach demonstrated by Deleuze and Guattari in A Thousand Plateaus. The model of multi-perspectivalism adopted in the thesis engages in establishing connections and similarities between theories, rather than emphasizing contradictory and exclusive practices. The Foucauldian notion of the rules of formation in discourse, Nichols’ theories of documentary representation of reality, Bordwell’s schematic interpretation, and several other positions are critiqued, as the line of flight embarked upon in the thesis intersects with, and passes through both textual and theoretical boundaries. The thesis consists of two parts: firstly, a location of theoretical perspective, in which the issues of theory pertaining to actuality and narrative are explicated, and the methodological approach of the thesis is defined. The second part commences with an analysis of the most familiar instances of actuality in film and television, with particular attention to documentary forms. It then engages in the analysis of films that represent actuality but which, in the process of narrativization, display a convergence of genre conventions. The films selected for analysis include Steven Speilberg's Schindler's List, (1993) Oliver Stone's JFK, (1991) and Robert Zemeckis' Forrest Gump, (1994) and Contact, (1996). Hence the thesis is concerned with the application of a pluralist theoretical approach, with, however, an emphasis on the Deleuzo-Guattarian notions of rhizome and assemblage. Within this theoretical frame, the connections between actuality and the audio/visual text are explicated, and the formation of text as ‘a rhizome with the world’, is analyzed across a range of examples.