998 resultados para Constitutive Relation


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Atheromatous plaque rupture h the cause of the majority of strokes and heart attacks in the developed world. The role of calcium deposits and their contribution to plaque vulnerability are controversial. Some studies have suggested that calcified plaque tends to be more stable whereas others have suggested the opposite. This study uses a finite element model to evaluate the effect of calcium deposits on the stress within the fibrous cap by varying their location and size. Plaque fibrous cap, lipid pool and calcification were modeled as hyperelastic, Isotropic, (nearly) incompressible materials with different properties for large deformation analysis by assigning time-dependent pressure loading on the lumen wall. The stress and strain contours were illustrated for each condition for comparison. Von Mises stress only increases up to 1.5% when varying the location of calcification in the lipid pool distant to the fibrous cap. Calcification in the fibrous cap leads to a 43% increase of Von Mises stress when compared with that in the lipid pool. An increase of 100% of calcification area leads to a 15% stress increase in the fibrous cap. Calcification in the lipid pool does not increase fibrous cap stress when it is distant to the fibrous cap, whilst large areas of calcification close to or in the fibrous cap may lead to a high stress concentration within the fibrous cap, which may cause plaque rupture. This study highlights the application of a computational model on a simulation of clinical problems, and it may provide insights into the mechanism of plaque rupture.

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Measurement of the relation between polarisation and electric field for ferroelectric trissarcosine calcium chloride (TSCC) was made in the pressure range up to 6 kbar. The pressure dependence of the spontaneous polarisation and the coercive field were obtained, and the existence of a new pressure-induced phase and the paraelectric- ferroelectric-new phase triple point were found.

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This doctoral thesis in theoretical philosophy is a systematic analysis of Karl Popper's philosophy of science and its relation to his theory of three worlds. The general aim is to study Popper's philosophy of science and to show that Popper's theory of three worlds was a restatement of his earlier positions. As a result, a new reading of Popper's philosophy and development is offered and the theory of three worlds is analysed in a new manner. It is suggested that the theory of three worlds is not purely an ontological theory, but has a profound epistemological motivation. In Part One, Popper's epistemology and philosophy of science is analysed. It is claimed that Popper's thinking was bifurcated: he held two profound positions without noticing the tension between them. Popper adopted the position called the theorist around 1930 and focused on the logical structure of scientific theories. In Logik der Forschung (1935), he attempted to build a logic of science on the grounds that scientific theories may be regarded as universal statements which are not verifiable but can be falsified. Later, Popper emphasized another position, called here the processionalist. Popper focused on the study of science as a process and held that a) philosophy of science should study the growth of knowledge and that b) all cognitive processes are constitutive. Moreover, the constitutive idea that we see the world in the searchlight of our theories was combined with the biological insight that knowledge grows by trial and error. In Part Two, the theory of three worlds is analysed systematically. The theory is discussed as a cluster of theories which originate from Popper's attempt to solve some internal problems in his thinking. Popper adhered to realism and wished to reconcile the theorist and the processionalist. He also stressed the real and active nature of the human mind, and the possibility of objective knowledge. Finally, he wished to create a scientific world view.

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Typically, in bag-stack or silo fumigations the concentration of phosphine is not constant, and yet most of what is known about phosphine efficacy against grain insects comes from studies with fixed concentrations. Indeed, where changing concentration experiments have been performed, researchers have been unable to explain observed efficacy on the basis of data from fixed concentrations. The ability to predict insect mortality in relation to changing phosphine concentrations would facilitate the development of effective fumigation protocols. In this paper, we explore the prospects for making such predictions. After reviewing published and new results, we conclude that the commonly used concentration x time (Ct) product is unreliable for this purpose. New results, for a strongly resistant strain of Rhyzopertha dominica from Australia, suggest that the relationship Cnt = k may be useful for predicting mortality of this type of insect in changing concentrations. However, in the case of a strain of Sitophilus oryzae with a type of resistance common in Australian S. oryzae, the relationship Cnt = k proved to be less reliable.

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Adults of a phosphine-resistant strain of Sitophilus oryzae (L) were exposed to constant phosphine concentrations of 0.0035-0.9 mg litre(-1) for periods of between 20 and 168 h at 25 °C, and the effects of time and concentration on mortality were quantified. Adults were also exposed to a series of treatments lasting 48, 72 or 168 h at 25 °C, during which the concentration of phosphine was varied. The aim of this study was to determine whether equations from experiments using constant concentrations could be used to predict the efficacy of changing phosphine concentrations against adults of S oryzae. A probit plane without interaction, in which the logarithms of time (t) and concentration (C) were variables, described the effects of concentration and time on mortality in experiments with constant concentrations. A derived equation of the form C^nt = k gave excellent predictions of toxicity when applied to data from changing concentration experiments. The results suggest that for resistant S oryzae adults there is nothing inherently different between constant and changing concentration regimes, and that data collected from fixed concentrations can be used to develop equations for predicting mortality in fumigations in which phosphine concentration changes. This approach could simplify the prediction of efficacy of typical fumigations in which concentrations tend to rise and then fall over a period of days.

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Superconductivity is found in tetragonal La3−x Ba3+x Cu6O14+δ and La, Ba)6−x Sr x Cu6O14+δ even though they do not possess Cu-O chains or the K2NiF4 structure. Resistivity measurements confirm the occurrence of a transformation from chain-superconductivity to sheet-superconductivity in YBa2Cu3O7−δ as δ is varied in the range 0.0–0.5.

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The dissertation analyses the political culture of Sweden during the reign of King Gustav III (1771-1792). This period commonly referred to as the Gustavian era followed the so-called Age of Liberty ending half a century of strong parliamentary rule in Sweden. The question at the heart of this study engages with the practice of monarchical rule under Gustav III, its ideological origins and power-political objectives as well as its symbolic expression. The study thereby addresses the very nature of kingship. In concrete terms, why did Gustav III, his court, and his civil service vigorously pursue projects that contemporaneous political opponents and, in particular, subsequent historiography have variously pictured as irrelevant, superficial, or as products of pure vanity? The answer, the study argues, is to be found in patterns of political practice as developed and exercised by Gustav III and his administration, which formed a significant part of the political culture of Gustavian Sweden. The dissertation is divided into three parts. The first traces the use and development of royal graces chivalric orders, medals, titles, privileges, and other gifts issued by the king. The practice of royal reward is illustrated through two case studies: the 1772 coup d état that established Gustav III s rule, and the birth and baptism of the crown prince, Gustav Adolf, in 1778. The second part deals with the establishment of the Court of Appeal in Vasa in 1776. The formation of the Appeals Court was accompanied by a host of ceremonial, rhetorical, emblematic, and architectural features solidifying its importance as one of Gustav III s most symbolic administrative reform projects and hence portraying the king as an enlightened monarch par excellence. The third and final part of the thesis engages with war as a cultural phenomenon and focuses on the Russo-Swedish War of 1788-1790. In this study, the war against Russia is primarily seen as an arena for the king and other players to stage, create and re-create as well as articulate themselves through scenes and roles adhering to a particular cultural idiom. Its codes and symbolic forms, then, were communicated by means of theatre, literature, art, history, and classical mythology. The dissertation makes use of a host of sources: protocols, speeches, letters, diaries, newspapers, poetry, art, medals, architecture, inscriptions and registers. Traditional political source material and literary and art sources are studied as totalities, not as separate entities. Also it is argued that political and non-fictional sources cannot be understood properly without acknowledging the context of genre, literary conventions, and artistic modes. The study critically views the futile, but nonetheless almost habitual juxtaposition of the reality of images, ideas, and metaphors, and the reality of supposedly factual historical events. Significantly, the thesis presumes the symbolic dimension to be a constitutive element of reality, not its cooked up misrepresentation. This presumption is reflected in a discussion of the concept of role , which should not be anachronistically understood as roles in which the king cast himself at different times and in different situations. Neither Gustav III nor other European sovereigns of this period played the roles as rulers or majesties. Rather, they were monarchs both in their own eyes and in the eyes of their contemporaries as well as in all relations and contexts. Key words: Eighteenth-Century, Gustav III, Cultural History, Monarchs, Royal Graces, the Vasa Court of Appeal, the Russo-Swedish War 1788–1790.

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Seagrass meadows across north-eastern Australia, survive a range of environmental conditions in coastal bays, reefs, estuarine and deepwater habitats through adaptation of a range of structural, morphological and physiological features. The aim of this study was to investigate the influence of spatial features (habitat type, site and depth) and photon flux on the photosynthetic performance of 11 tropical seagrass species. Pulse amplitude modulated (PAM) fluorometry was used to generate rapid light curves from which measures of maximal electron transport rate (ETRmax), photosynthetic efficiency (?), saturating irradiance (Ek) and effective quantum yield (?F/Fm?) were derived. The amount of light absorbed by leaves (absorption factor) was also determined for each population. In intertidal habitats many seagrass species exhibited typical sun-type responses with a close coupling of both ETRmax and Ek with photon flux. Photosynthetic performance ranged from minima in Thalassodendron ciliatum to maxima in Syringodium isoetifolium. The absence of a coupling between photosynthetic performance and photon flux in subtidal populations was most likely due to highly variable light climates and possible light attenuation, and hence the photo-biology of estuarine and deepwater seagrasses exhibited photosynthetic responses indicative of light limitation. In contrast seagrass species from shallow reef and coastal habitats for the most part exhibited light saturation characteristics. Of all the variables examined ETRmax, Ek and ?F/Fm? were most responsive to changing light climates and provide reliable physiological indicators of real-time photosynthetic performance of tropical seagrasses under different light conditions.

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The first larval instar has been identified as a critical stage for population mortality in Lepidoptera, yet due to the body size of these larvae, the factors that contribute to mortality under field conditions are still not clear. Dispersal behaviour has been suggested as a significant, but ignored factor contributing to mortality in first-instar lepidopteran larvae. The impact that leaving the host plant has on the mortality rate of Helicoverpa armigera neonates was examined in field crops and laboratory trials. In this study the following are examined: (1) the effects of soil surface temperature, and the level of shade within the crop, on the mortality of neonates on the soil after dropping off from the host plant; (2) the percentage of neonates that dropped off from a host plant and landed on the soil; and (3) the effects of exposure to different soil surface temperatures on the development and mortality of neonates. The findings of this study showed that: (1) on the soil, surface temperatures above 43°C were lethal for neonates, and exposure to these temperatures contributed greatly to the overall mortality rate observed; however, the fate of neonates on the soil varied significantly depending on canopy closure within the crop; (2) at least 15% of neonates dropped off from the host plant and landed on the soil, meaning that the proportion of neonates exposed to these condition is not trivial; and (3) 30 min exposure to soil surface temperatures approaching the lethal level (>43°C) has no significant negative effects on the development and mortality of larvae through to the second instar. Overall leaving the plant through drop-off contributes to first-instar mortality in crops with open canopies; however, survival of neonates that have lost contact with a host plant is possible, and becomes more likely later in the crop growing season.

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A constitutive modeling approach for shape memory alloy (SMA) wire by taking into account the microstructural phase inhomogeneity and the associated solid-solid phase transformation kinetics is reported in this paper. The approach is applicable to general thermomechanical loading. Characterization of various scales in the non-local rate sensitive kinetics is the main focus of this paper. Design of SMA materials and actuators not only involve an optimal exploitation of the hysteresis loops during loading-unloading, but also accounts for fatigue and training cycle identifications. For a successful design of SMA integrated actuator systems, it is essential to include the microstructural inhomogeneity effects and the loading rate dependence of the martensitic evolution, since these factors play predominant role in fatigue. In the proposed formulation, the evolution of new phase is assumed according to Weibull distribution. Fourier transformation and finite difference methods are applied to arrive at the analytical form of two important scaling parameters. The ratio of these scaling parameters is of the order of 10(6) for stress-free temperature-induced transformation and 10(4) for stress-induced transformation. These scaling parameters are used in order to study the effect of microstructural variation on the thermo-mechanical force and interface driving force. It is observed that the interface driving force is significant during the evolution. Increase in the slopes of the transformation start and end regions in the stress-strain hysteresis loop is observed for mechanical loading with higher rates.

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Based on a one-year ethnographic study of a primary school in Finland with specialised classes in Finnish and English (referred to as bilingual classes by research participants), this research traces patterns of how nationed, raced, classed and gendered differences are produced and gain meaning in school. I examine several aspects of these differences: the ways the teachers and parents make sense of school and of school choice; the repertoires of self put forward by teachers, parents and pupils of the bilingual classes; and the insitutional and classroom practices in Sunny Lane School (pseudonym). My purpose is to examine how the construction of differentness is related to the policy of school choice. I approach this questions from a knowledge problematic, and explore connections and disjunctions between the interpretations of teachers and those of parents, as well as between what teachers and parents expressed or said and the practices they engaged in. My data consists of fieldnotes generated through a one-year period of ethnographic study in Sunny Lane School, and of ethnographic interviews with teachers and parents primarily of the bilingual classes. This data focuses on the initial stages of the bilingual classes, which included the application and testing processes for these classes, and on Grades 1─3. In my analysis, I pursue poststructural feminist theorisations on questions of knowledge, power and subjectivity, which foreground an understanding of the constitutive force of discourse and the performative, partial, and relational nature of knowledge. I begin by situating my ethnographic field in relation to wider developments, namely, the emergence of school choice and the rhetoric of curricular reform and language education in Finland. I move on from there to ask how teachers discuss the introduction of these specialised classes, then trace pupils paths to these classes, their parents goals related to school choice, teachers constructions of the pupils and parents of bilingual classes, and how these shape the ways in which school and classroom practices unfold. School choice, I argue, functioned as a spatial practice, defining who belongs in school and demarcating the position of teachers, parents and pupils in school. Notions of classed and ethnicised differences entered the ways teachers and parents made sense of school choice. Teachers idealised school in terms of social cohesiveness and constructed social cohesion as a task for school to perform. The hopes parents iterated were connected to ensuring their children s futurity, to their perceptions of the advantages of fluency in English, but also to the differences they believed to exist between the social milieus of different schools. Ideals such as openmindedness and cosmopolitanism were also articulated by parents, and these ideals assumed different content for ethnic majority and minority parents. Teachers discussed the introduction of bilingual classes as being a means to ensure the school s future, and emphasised bilingual classes as fitting into the rubric of Finnish comprehensive schooling which, they maintained, is committed to equality. Parents were expected to accommodate their views and adopt the position of the responsible, supportive parent that was suggested to them by teachers. Teachers assumed a posture teachers of appreciating different cultures, while maintaining Finnishness as common ground in school. Discussion on pupils knowledge and experience of other countries took place often in bilingual classes, and various cultural theme events were organized on occasion. In school, pupils are taught to identify themselves in terms of cultural belonging. The rhetoric promoted by teachers was one of inclusiveness, which was also applied to describe the task of qualifying pupils for bilingual classes, qualifying which pupils can belong. Bilingual classes were idealised as taking a neutral, impartial posture toward difference by ethnic majority teachers and parents, and the relationship of school choice to classed advantage, for example, was something teachers, as well as parents, preferred not to discuss. Pupils were addressed by teachers during lessons in ways that assumed self responsibility and diligence, and they assumed the discursive category of being good, competent pupils made available to them. While this allowed them to position themselves favourably in school, their participation in a bilingual class was marked by the pressure to succeed well in school.

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We analyse the corporate governance and performance relation, when conditioning on corporate fraud, for fraud firms during 2000 – 2007. Fraud firms are identified as either self- reported fraud events, or subject to regulatory investigation. We use the inverse Mills ratio procedure to account for firms' (unobservable) fraud culture in the dynamic system GMM model of the performance- governance relation. We find that corporate governance is an endogenously determined characteristic that has no causal impact on firm performance when conditioning on fraud. Fraud is a significant regulatory event but its overall economic impact at the firm level is highly variable.

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This paper investigates the association between global community concerns about bribery activities and anti-bribery disclosure practices by two Chinese telecommunication companies operating internationally, namely China Mobile and ZTE. Based on content analysis of annual reports and global news media articles over a period of 16 years from 1995-2010, the findings suggest that the changes in the level of disclosures by the two major Chinese telecommunications companies were closely associated with the level of international concerns over bribery practices within the Chinese telecommunications industry. This finding indicates that the companies adopt anti-bribery disclosure practices in order to minimise the gap of trust (Social capital) between companies themselves and global stakeholders. In this paper we argue that, for domestic companies in China, culturally constructed social capital, such as guanxi, creates a level of trust between managers and their stakeholders, which obviates the need for managers to disclose anti-bribery performance information. However, for companies operating internationally, as social capital is inadequate to bridge the gap of trust between managers and global stakeholders, managers use disclosures of anti-bribery performance information as a way to minimise such a gap.

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Mature green mango fruits of commercially important varieties were screened to investigate the levels of constitutive antifungal compounds in peel and to assess anthracnose disease after inoculation with Colletotrichum gloeosporioides. High pressure liquid chromatography was used to quantify the levels of 5-n-heptadecenylresorcinol and 5-n-pentadecylresorcinol in the peel extracts. The fruit peel of the varieties ‘Kensington Pride’ and ‘Keitt’ were observed to have the highest levels of both 5-n-heptadecenylresorcinol (107.3-123.7 and 49.9-61.4 μg/g FW, respectively) and 5-n-pentadecylresorcinol (6.32-7.99 and 3.30-6.05 μg/g FW, respectively), and the fruit of the two varieties were found to have some resistance to postharvest anthracnose. The varieties ‘Kent’, ‘R2E2’, ‘Nam Doc Mai’, ‘Calypso’, and ‘Honey Gold’ contained much lower concentrations of resorcinols in their peel and three of these varieties were found to be more susceptible to anthracnose. Concentrations of 5-nheptadecenylresorcinol were significantly lower at the ‘sprung’ and ‘eating ripe’ stages of ripening compared to levels at harvest. Concentrations of 5-n-pentadecylresorcinol did not differ significantly across the three stages of ripening. The levels of these two resorcinols were found to be strongly inter-correlated (P < 0.001, r2 = 0.71), with concentrations of 5-nheptadecenylresorcinol being an average 18 times higher than those of 5-npentadecylresorcinol. At the ‘eating ripe’ stage, significant relationships were observed between the concentrations of each type of alk(en)ylresorcinol and anthracnose lesion areas following postharvest inoculation, P<0.001, r2= 0.69 for 5-n pentadecylresorcinol, and P<0.001, r2= 0.44 for 5-n-heptadecenylresorcinol.