973 resultados para Light and darkness in literature.


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Natural light and its provision within asylum and other buildings is a neglected aspect of the historical archaeology of institutions. An Edwardian asylum in the north of Ireland is analysed for the management of natural light through the siting of buildings, window design and placement of interior glazing. A close reading of selected contemporary literature relating to natural light is employed to assess the significance of light provision within institutions of this period and contemporary discourses are in turn illuminated by the material practices recorded in the case study.

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It is well known that clocks are present in brain regions other than the suprachiasmatic nucleus and in many peripheral tissues. In the teleost, Danio rerio, peripheral oscillators can be directly synchronized by light. Danio rerio ZEM-2S embryonic cells respond to light with differential growth: cells kept in constant light exhibited a strong inhibition of proliferation, whereas in cells kept in light:dark (LD) cycles (14L:10D and 10L:14D) or in constant darkness (DD), the doubling times were not statistically different. We demonstrated by RT-PCR followed by PCR that ZEM-2S cells express two melanopsins, Opn4x and Opn4m, and the six Cry genes. The presence of the protein OPN4x was demonstrated by immunocytochemistry. The pattern of temporal expression of the genes Opn4x, Per1, Cry1b, and Clock was studied in ZEM-2S cells kept for five days in 12L:12D or DD. In 12L:12D, the clock genes Per 1 and Cry1b exhibited robust circadian expression, while Opn4x and Clock expression seemed to vary in an ultradian pattern. Both Per1 and Cry1b genes had higher expression during the L phase; Clock gene had an increase in expression coincident with the D phase, and during the subjective night. In DD, the temporal variation of Per1 and Cry1b genes was greatly attenuated but not extinguished, and the higher expressions were shifted to the transition times between subjective day and night, demonstrating that Per and Cry1b were synchronized by the LD cycle. Clock and Opn4x kept the ultradian oscillation, but the rhythm was not statistically significant. As endothelins (ET) have been reported to be a potent stimulator of Per genes in rodents, we investigated the effect of endothelin on ZEM-2S cells, which express ETA receptors. Cells were kept in 12D:12L for five days, and then treated with 10-11 to 10-8M ET-1 for 24h. ET-1 exhibited a biphasic effect on Opn4x expression. At 10-11M, the hormone exerted a highly significant stimulation of Opn4x expression during the L phase and introduced a circadian oscillatory pattern. At 10-10M, a significant increase was seen at ZT21 and ZT0 (i.e., at the end of the D phase and beginning of the L phase), whereas 10-9 and 10-8M ET-1 inhibited the expression of Opn4x at most ZTs. Clock expression was unaffected by 10-8M ET-1; however, in the presence of lower concentrations, the expression was enhanced at some ZTs, strengthening the ultradian oscillation. ET-1 at 10-11 and 10-10M had no effect on Per1 circadian expression; however, 10-9 and 10-8M ET-1 reduced the amplitude of Per1 expression in the beginning of the L phase. ET-1 effects were less evident on Cry 1b. For both genes, the reduction in expression was not sufficient to abolish the circadian oscillatory pattern. Based on these results and data in the literature, a link between ET-1 stimulation of ETA receptors may be established by E4BP4 binding to the promoters and consequent inhibition of gene expression.

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This project was concerned with the perception of size constancy of simple, elongated and planar objects in the light and dark. The main findings are: transverse, vertical and medial axes give rise to different degrees of size constancy; true size and shape of the objects proved to be a factor in size constancy; the size-distance invariance hypothesis (SDIH) cannot explain underconstancy in the light, and perfect constancy in the dark.

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In Le Guin's Earthsea Quartet, knowledge of the name of a thing or person guarantees control over their destiny. In a world where light and darkness co-exist and where dragons are an extension of humans, a name is the means with which one can achieve one's vision of the world. If utopia is the individual projection of a supposedly collective ideal, then knowledge of names is the vehicle for the realization of one's own utopia, which may well come into conflict with the utopias of others. However, Earthsea is not simply a series of battles between individual utopists. Earthsea itself constitutes a precarious and non-traditional utopia, where antithetical sides co-exist and neither prevails forever. As its name denotes, “earth” and “sea,” darkness and light, tombs and open seas, tiny islands and eternal journeys operate together to produce the setting for the novels and enable the chase of an ever-elusive knowledge. For as the utopists in Earthsea find out, knowledge can only be complete if it also comprises its Jungian opposite, namely ignorance. In an attempt to explore the relation between utopia, knowledge, and ignorance, this article employs psychology and linguistics, and constructs a description of a “just” world which remains necessarily utopian.

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A look at the role that symbolism plays in the novel. In this case, as it is in many other great novels, we see that symbolism is used to enhance the mood and the atmosphere of the novel rather than adding anything of importance to the plot.

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The avian circadian system is composed of the retina, the mammalian homolog region of the suprachiasmatic nucleus (SNC), and the pineal gland. The retina, itself, displays many rhythmic physiological events, such as movements of photoreceptor cells, opsin expression, retinal reisomerization, and melatonin and dopamine production and secretion. Altogether, these rhythmic events are coordinated to predict environmental changes in light conditions during the day, optimizing retina function. The authors investigated the expression pattern of the melanopsin genes Opn4x and Opn4m, the clock genes Clock and Per2, and the genes for the key enzymes N-Acetyltransferase and Tyrosine Hidroxylase in chicken embryo dispersed retinal cells. Primary cultures of chicken retina from 8-day-old embryos were kept in constant dark (DD), in 12-h light/12-h dark (12L:12D), in 12L:12D followed by DD, or in DD in the absence or presence of 100 mu M glutamate for 12 h. Total RNA was extracted throughout a 24-h span, every 3 h starting at zeitgeber time 0 (ZT0) of the 6th day, and submitted to reverse transcriptase-polymerase chain reaction (RT-PCR) followed by quantitative PCR (qPCR) for mRNA quantification. The data showed no rhythmic pattern of transcription for any gene in cells kept in DD. However under a light-dark cycle, Clock, Per2, Opn4m, N-Acetyltransferase, and Tyrosine Hydroxylase exhibited rhythmic patterns of transcription. In DD, 100 mu M glutamate was able to induce rhythmic expression of Clock, strongly inhibited the expression of Tyrosine Hydroxylase, and, only at some ZTs, of Opn4x and Opn4m. The neurotransmitter had no effect on Per2 and N-Acetyltransferase transcription. The authors confirmed the expression of the protein OPN4x by immunocytochemistry. These results suggest that chicken embryonic retinal cells contain a functional circadian clock, whose synchronization requires light-dark cycle or glutamate stimuli. (Author correspondence: amdlcast@ib.usp.br).

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In her book 'Living on Light', Jasmuheen tries to animate people worldwide to follow her drastic nutrition rules in order to boost their quality of life. Several deaths have been reported as a fatal consequence. A doctor of chemistry who believably claimed to have been 'living on light' for 2 years, except for the daily intake of up to 1.5 l of fluid containing no or almost no calories was interested in a scientific study on this phenomenon. PARTICIPANT AND METHODS: The 54-year-old man was subjected to a rigorous 10-day isolation study with complete absence of nutrition. During the study he obtained an unlimited amount of tea and mineral water but had no caloric intake. Parameters to monitor his metabolic and psychological state and vital parameters were measured regularly and the safety of the individual was ensured throughout the study. The subject agreed on these terms and the study was approved by the local ethics committee.

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Intercultural Approaches to Cities and Spaces in Literature, Film, and New Media: a review of new work by Manzanas and Benito and Lopez-Varela and Net

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The European Commission’s Action Plan consists, in a nutshell, of a short list of technical proposals and a longer one of (rather general) potential actions. Overall, the plan indeed proposes to achieve some short-term objectives, such as a reduction of listing costs for SMEs, but it lacks long-term vision. The plan bundles actions under rather generic objectives of long-term finance or cross-border investing. Improving the informational infrastructure (e.g. accounting standards, company data) and cross-border enforcement of rules is left to vaguely defined future actions, but these constitute the core of the capital markets infrastructure. Without a well-defined set of measurable objectives, the whole plan may lose political momentum and become an opportunity for interested parties to cherry pick their pet provisions. Building a single market, i.e. removing cross-border obstacles to capital circulation, is too challenging a task to simply appear as one of many items on a long list of general objectives, which incidentally do not include institutional reform. The ultimate risk is that the Commission may just miss a unique opportunity to revamp and improve the financial integration process in Europe after almost a decade of harmful financial retrenchment.