960 resultados para light sources
Resumo:
Zeaxanthin, along with its isomer lutein, are the major carotenoids contributing to the characteristic colour of yellow sweet-corn. From a human health perspective, these two carotenoids are also specifically accumulated in the human macula, and are thought to protect the photoreceptor cells of the eye from blue light oxidative damage and to improve visual acuity. As humans cannot synthesise these compounds, they must be accumulated from dietary components containing zeaxanthin and lutein. In comparison to most dietary sources, yellow sweet-corn (Zea mays var. rugosa) is a particularly good source of zeaxanthin, although the concentration of zeaxanthin is still fairly low in comparison to what is considered a supplementary dose to improve macular pigment concentration (2 mg/person/day). In our present project, we have increased zeaxanthin concentration in sweet-corn kernels from 0.2 to 0.3 mg/100 g FW to greater than 2.0 mg/100 g FW at sweet-corn eating-stage, substantially reducing the amount of corn required to provide the same dosage of zeaxanthin. This was achieved by altering the carotenoid synthesis pathway to more than double total carotenoid synthesis and to redirect carotenoid synthesis towards the beta-arm of the pathway where zeaxanthin is synthesised. This resulted in a proportional increase of zeaxanthin from 22% to 70% of the total carotenoid present. As kernels increase in physiological maturity, carotenoid concentration also significantly increases, mainly due to increased synthesis but also due to a decline in moisture content of the kernels. When fully mature, dried kernels can reach zeaxanthin and carotene concentrations of 8.7 mg/100 g and 2.6 mg/100 g, respectively. Although kernels continue to increase in zeaxanthin when harvested past their normal harvest maturity stage, the texture of these 'over-mature' kernels is tough, making them less appealing for fresh consumption. Increase in zeaxanthin concentration and other orange carotenoids such as p-carotene also results in a decline in kernel hue angle of fresh sweet-corn from approximately 90 (yellow) to as low as 75 (orange-yellow). This enables high-zeaxanthin sweet-corn to be visually-distinguishable from standard yellow sweet-corn, which is predominantly pigmented by lutein.
Resumo:
In the study, we used the Agilent 8453 spectrophotometer (which is equipped with a limiting aperture that restricts the light beam to the central 5 mm of the contact lens), to measure the transmittance of various coloured contact lenses including the one Day Acuvue define manufactured by Johnson and Johnson which the authors represent. We measured the instrument baseline before the transmittance spectra of lenses were tested. The values of lens transmittances were thus the difference between baseline and lens measurement at each time. The transmittance measurements were obtained at 0.5 nm intervals, from 200 to 700 nm after a soak in saline to remove the influence of any surface active agents within the packaging products. The technique used in our study was not very different from how other research studies [2], [3], [4], [5] and [6] have measured the spectra transmittances of contact lenses...
Resumo:
Sea-finding behavior in sea turtle hatchlings is modified by the visual cues provided by artificial beach front lighting. The consequent landward movement of hatchlings in response to coastal electric lighting reduces their survival rates. We assessed the potential impact of coastal lighting at Rushikulya, an important mass nesting site of the olive ridley sea turtle (Lepidochelys olivacea) in the Indian Ocean region. We examined the response of hatchlings to light characteristics in an experimental setup, as well as to the existing lighting regimes along the beach, using arena trials. Previous studies on other species indicate preferential orientation towards low wavelength and high intensity light. Our study confirms these preferences among hatchlings from the Indian Ocean population of olive ridleys. In addition we also found that wavelength and intensity could have an interactive effect upon hatchling orientation. Hatchlings at the study site respond both to visible point sources of light and to sheer glows of light. Though beach plantations of introduced Casuarina equisetifolia are generally considered to have negative impacts on sea turtle nesting beaches, we found that they acted as an effective light barrier when planted about 50 m away from the high tide line. We developed a model of the expected impact of artificial lighting on hatchling orientation during mass hatching events of previous years, and predict as much as 50% misorientation in some years. We also developed a map representing the misorientation of hatchlings due to artificial lighting based on arena trials in different regions of the beach. The results of the study helped identify focal areas for light management on the beach, which could be critical for the survival of this population.
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The specific activity of glutamine synthetase (L-glutamate: ammonia ligase, EC 6.3.1.2) in surface grown Aspergillus niger was increased 3-5 fold when grown on L-glutamate or potassium nitrate, compared to the activity obtained on ammonium chloride. The levels of glutamine synthetase was regulated by the availability of nitrogen source like NH4 + , and further, the enzyme is repressed by increasing concentrations of NH4 +. In contrast to other micro-organisms, the Aspergillus niger enzyme was neither specifically inactivated by NH4+ or L-glutamine nor regulated by covalent modification.Glutamine synthetase from Aspergillus niger was purified to homogenity. The native enzyme is octameric with a molecular weight of 385,000±25,000. The enzyme also catalyses Mn2+ or Mg2+-dependent synthetase and Mn2+-dependent transferase activity.Aspergillus niger glutamine synthetase was completely inactivated by two mol of phenylglyoxal and one mol of N-ethylmaleimide with second order rate constants of 3·8 M–1 min–1 and 760 M–1 min–1 respectively. Ligands like Mg. ATP, Mg. ADP, Mg. AMP, L-glutamate NH4+, Mn2+ protected the enzyme against inactivation. The pattern of inactivation and protection afforded by different ligands against N-ethylamaleimide and phenylglyoxal was remarkably similar. These results suggest that metal ATP complex acts as a substrate and interacts with an arginine ressidue at the active site. Further, the metal ion and the free nucleotide probably interact at other sites on the enzyme affecting the catalytic activity.
Resumo:
A central tenet in the theory of reliability modelling is the quantification of the probability of asset failure. In general, reliability depends on asset age and the maintenance policy applied. Usually, failure and maintenance times are the primary inputs to reliability models. However, for many organisations, different aspects of these data are often recorded in different databases (e.g. work order notifications, event logs, condition monitoring data, and process control data). These recorded data cannot be interpreted individually, since they typically do not have all the information necessary to ascertain failure and preventive maintenance times. This paper presents a methodology for the extraction of failure and preventive maintenance times using commonly-available, real-world data sources. A text-mining approach is employed to extract keywords indicative of the source of the maintenance event. Using these keywords, a Naïve Bayes classifier is then applied to attribute each machine stoppage to one of two classes: failure or preventive. The accuracy of the algorithm is assessed and the classified failure time data are then presented. The applicability of the methodology is demonstrated on a maintenance data set from an Australian electricity company.
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This paper investigates the short-run effects of economic growth on carbon dioxide emissions from the combustion of fossil fuels and the manufacture of cement for 189 countries over the period 1961-2010. Contrary to what has previously been reported, we conclude that there is no strong evidence that the emissions-income elasticity is larger during individual years of economic expansion as compared to recession. Significant evidence of asymmetry emerges when effects over longer periods are considered. We find that economic growth tends to increase emissions not only in the same year, but also in subsequent years. Delayed effects - especially noticeable in the road transport sector - mean that emissions tend to grow more quickly after booms and more slowly after recessions. Emissions are more sensitive to fluctuations in industrial value added than agricultural value added, with services being an intermediate case. On the expenditure side, growth in consumption and growth in investment have similar implications for national emissions. External shocks have a relatively large emissions impact, and the short-run emissions-income elasticity does not appear to decline as incomes increase. Economic growth and emissions have been more tightly linked in fossil-fuel rich countries.
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I examine the portrayal of Jesus as a friend of toll collectors and sinners in the Third Gospel. I aim at a comprehensive view on the Lukan sinner texts, combining questions of the origin and development of these texts with the questions of Luke s theological message, of how the text functions as literature, and of the social-historical setting(s) behind the texts. Within New Testament scholarship researchers on the historical Jesus mostly still hold that a special mission to toll collectors and sinners was central in Jesus public activity. Within Lukan studies, M. Goulder, J. Kiilunen and D. Neale have claimed that this picture is due to Luke s theological vision and the liberties he took as an author. Their view is disputed by other Lukan scholars. I discuss methods which scholars have used to isolate the typical language of Luke s alleged written sources, or to argue for the source-free creation by Luke himself. I claim that the analysis of Luke s language does not help us to the origin of the Lukan pericopes. I examine the possibility of free creativity on Luke s part in the light of the invention technique used in ancient historiography. Invention was an essential part of all ancient historical writing and therefore quite probably Luke used it, too. Possibly Luke had access to special traditions, but the nature of oral tradition does not allow reconstruction. I analyze Luke 5:1-11; 5:27-32; 7:36-50; 15:1-32; 18:9-14; 19:1-10; 23:39-43. In most of these some underlying special tradition is possible though far from certain. It becomes evident that Luke s reshaping was so thorough that the pericopes as they now stand are decidedly Lukan creations. This is indicated by the characteristic Lukan story-telling style as well as by the strongly unified Lukan theology of the pericopes. Luke s sinners and Pharisees do not fit in the social-historical context of Jesus day. The story-world is one of polarized right and wrong. That Jesus is the Christ, representative of God, is an intrinsic part of the story-world. Luke wrote a theological drama inspired by tradition. He persuaded his audience to identify as (repenting) sinners. Luke's motive was that he saw the sinners in Jesus' company as forerunners of Gentile Christianity.
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The improvement terms in the generalised energy-momentum tensor of Callan, Coleman and Jackiw can be derived from a variational principle if the Lagrangian is generalised to describe coupling between ‘matter’ fields and a spin-2 boson field. The required Lorentz-invariant theory is a linearised version of Kibble-Sciama theory with an additional (generally-covariant) coupling term in the Lagrangian. The improved energy-momentum tensor appears as the source of the spin-2 field, if terms of second order in the coupling constant are neglected.
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The purpose of this study is to analyse the development and understanding of the idea of consensus in bilateral dialogues among Anglicans, Lutherans and Roman Catholics. The source material consists of representative dialogue documents from the international, regional and national dialogues from the 1960s until 2006. In general, the dialogue documents argue for agreement/consensus based on commonality or compatibility. Each of the three dialogue processes has specific characteristics and formulates its argument in a unique way. The Lutheran-Roman Catholic dialogue has a particular interest in hermeneutical questions. In the early phases, the documents endeavoured to describe the interpretative principles that would allow the churches to together proclaim the Gospel and to identify the foundation on which the agreement in the church is based. This investigation ended up proposing a notion of basic consensus , which later developed into a form of consensus that seeks to embrace, not to dismiss differences (so-called differentiated consensus ). The Lutheran-Roman Catholic agreement is based on a perspectival understanding of doctrine. The Anglican-Roman Catholic dialogue emphasises the correctness of interpretations. The documents consciously look towards a common future , not the separated past. The dialogue s primary interpretative concept is koinonia. The texts develop a hermeneutics of authoritative teaching that has been described as the rule of communion . The Anglican-Lutheran dialogue is characterised by an instrumental understanding of doctrine. Doctrinal agreement is facilitated by the ideas of coherence, continuity and substantial emphasis in doctrine. The Anglican-Lutheran dialogue proposes a form of sufficient consensus that considers a wide set of doctrinal statements and liturgical practices to determine whether an agreement has been reached to the degree that, although not complete , is sufficient for concrete steps towards unity. Chapter V discusses the current challenges of consensus as an ecumenically viable concept. In this part, I argue that the acceptability of consensus as an ecumenical goal is based not only the understanding of the church but more importantly on the understanding of the nature and function of the doctrine. The understanding of doctrine has undergone significant changes during the time of the ecumenical dialogues. The major shift has been from a modern paradigm towards a postmodern paradigm. I conclude with proposals towards a way to construct a form of consensus that would survive philosophical criticism, would be theologically valid and ecumenically acceptable.
Resumo:
Sangen ialo Rucous. The prayer book of the Schwenckfeldiens as a source for Michael Agricola The significance of the prayer book published by the Finnish reformer Michael Agricola in the year of 1544 has not been comprehended enough among the prayer literature of the Reformation century. Especially in foreign research literature one of the era s most extensive and versatile prayer books has been practically disregarded. According to the prayer book, Agricola appears to be a traditionalist, who derives most of his source material from medieval and old church prayer books. The low number of the prayers from Evangelical prayer books is noteworthy. The study in hand examines Agricola s theology expressed in his translation work of the prayer book of the mystic spiritualistic Schwenckfeldien movement. The prayer book of the Schwenckdeldiens diverged from Lutheranism was called Bekantnus der sünden and it was composed around the year of 1526. Agricola is the only prayer book collector who has regarded it as necessary to add all the 45 prayers of the Schwenckfeldien prayer book and its introduction to his book. In the prayers containing the Schwenckfeldien communion theology and Christology Agricola has not changed the content of the text, apparently because he was not aware of the problems involved in the Schwenckfeldien theology. On a few occasions Agricola added points of view concerning the church, priesthood, preaching the Word and sacraments to his prayers, which the Schwenckfeldiens despised. From the ten additions four Agricola created himself, the rest he borrowed from Wolfgang Capito s prayer book. As a source Agricola used Capito s Latin prayer book together with the German text from Bekantnus. When looking at the studied material, Agricola does not turn out to be a creative translator. Even though he had a model for a less restricted translation in Wolfgang Capito s prayer book, he sticks to his habit of translating word by word. Because not even a good example has had a liberating effect on his translation principles, Agricola cannot be considered a theologically orientated writer. The translation of the Schwenckfeldien prayers Agricola starts with Capito s prayer book. Very soon he takes the Bekantnus alongside Capito s text and abandons the use of Capito s prayer book in the middle of the translation process. Comparing Agricola s translation with the two texts in different languages has made it possible to create the disposition theory described above. On the basis of the disposition theory it can be concluded that Agricola first worked out a precise plan for his prayer book. Then he translated prayers theme by theme using multiple sources at the same time. Later Agricola fixed the disposition, which does not seem to have a direct paragon. From the prayers of the Schwenckfeldien prayer book Agricola translated 26 texts using the Bekantnus as an only base, from Capito s prayer book he translated four texts and 17 texts he translated using the two basic texts simultaneously. In the previous studies, words and texts added by Agricola have been examined as one problem unit. In this study the additions have been placed into three different categories: additions consequential on tautological parataxis, specifying additions and additions significant to the content. Due to Agricola s meticulous translation techniques, there are so few additions. Agricola does not show his own creativity even in the additions significant to the content but uses there some complete sentences or word fragments from the other prayers he has translated. In the translations of the prayers there are some unique appearing words and the analysis of the translation work shed a new light on the background of their first literary appearance in Finnish. Agricola s linguistic abilities turned out to be great. In those prayers where Agricola uses both the German and Latin basic texts at the same time, the translation process is a very intensive twine made on the basis of the two sources.
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PURPOSE The purpose of this study was to examine the relationship between objectively measured ambient light exposure and longitudinal changes in axial eye growth in childhood. METHODS A total of 101 children (41 myopes and 60 nonmyopes), 10 to 15 years of age participated in this prospective longitudinal observational study. Axial eye growth was determined from measurements of ocular optical biometry collected at four study visits over an 18-month period. Each child’s mean daily light exposure was derived from two periods (each 14 days long) of objective light exposure measurements from a wrist-worn light sensor. RESULTS Over the 18-month study period, a modest but statistically significant association between greater average daily light exposure and slower axial eye growth was observed (P ¼ 0.047). Other significant predictors of axial eye growth in this population included children’s refractive error group (P < 0.001), sex (P < 0.01), and age (P < 0.001). Categorized according to their objectively measured average daily light exposure and adjusting for potential confounders (age, sex, baseline axial length, parental myopia, nearwork, and physical activity), children experiencing low average daily light exposure (mean daily light exposure: 459 6 117 lux, annual eye growth: 0.13 mm/y) exhibited significantly greater eye growth than children experiencing moderate (842 6 109 lux, 0.060 mm/y), and high (1455 6 317 lux, 0.065 mm/y) average daily light exposure levels (P ¼ 0.01). CONCLUSIONS In this population of children, greater daily light exposure was associated with less axial eye growth over an 18-month period. These findings support the role of light exposure in the documented association between time spent outdoors and childhood myopia.
Resumo:
• Although there is evidence that outdoor activity is an important factor involved in the development of childhood refractive error,1,2 the mechanism underlying the association between more outdoor activity and less myopia in childhood is not clear. • In this prospective longitudinal study, the relationship between objectively measured ambient light exposure and eye growth in childhood was examined.
Resumo:
This dissertation is a study of some aspects of theoretical philosophy of the early modern thinker Thomas Hobbes (1588-1679). The focal point of the work is Hobbes s conception of imagination, which is discussed from both a systematic and a historical point of view, as well as in the light of contemporary scholarship. I argue that though there are significant similarities between the view of Hobbes and that of his predecessors, he gives a novel theory of imagination, which clarifies not only early modern discussions on human nature, knowledge, science, and literary criticism, but above all his own versatile philosophy. The prologue of the dissertation introduces methodological principles and gives critical remarks on the standard view of Hobbes. In Chapter II, I discuss the prominent theories of imagination before Hobbes and link them to his account. I argue that though Hobbes adopted the Aristotelian framework, his view is not reduced to it, as he borrows from various sources, for instance, from the Stoics and from Renaissance thought. Chapters III and IV form the psychological part of the work. In the Chapter III I argue that imagination, not sense, is central in the basic cognitive operations of the mind and that imagination has a decisive role in Hobbes s theory of motivation. The Chapter IV concentrates on various questions of Hobbes s philosophy of language. The chapter ends with a defence of a less naturalistic reading of Hobbes s theory of human nature. Chapters V and VI form the epistemological part of the work. I suggest, contrary to what has been recently claimed, that though Hobbes s ideas of good literary style do have a point of contact with his philosophy (e.g. the psychology of creative process), his ideas in the field are independent of his project of demonstrative political science. Instead I argue that the novelty of his major political work, Leviathan (1651), is based on a new theory of knowledge which he continued to develop in the post-Leviathan works. Chapter VII seeks to connect the more theoretical conclusions of Chapters V and VI to Hobbes's idea(l) of science as well as to his philosophical practice. On the basis of Hobbes s own writings as well as some historical examinations, I argue that method is not an apt way to conceptualise Hobbes s philosophical practice. Contemporary readings of Hobbes s theory of science are critically discussed and the chapter ends with an analysis of Hobbes s actual argumentation. In addition to the concluding remarks, the epilogue suggest three things: first, imagination is central when trying to understand Hobbes s versatile philosophy; second, that it is misleading to depict Hobbes as a simple materialist, mechanist, and empiricist; and, third, that in terms of imagination his influence on early modern thought has not been fully appreciated.
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The blue emission of polyfluorene (PF)-based light-emitting diodes (LEDs) is known to degrade due to a low-energy green emission, which hitherto has been attributed to oxidative defects. By studying the electroluminescence (EL) from ethyl-hexyl substituted PF LEDs in the presence of oxygen and in an inert atmosphere, and by using trace quantities of paramagnetic impurities (PM) in the polymer, we show that the triplet states play a major role in the low-energy emission mechanism. Our time-dependent many-body studies show a large cross-section for the triplet formation in the EL process in the presence of PM, primarily due to electron-hole recombination processes.