420 resultados para Darkness


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Removal of deposited eggs could be a useful control strategy for the damaging fish ectoparasite Argulus foliaceus, but focused control requires knowledge of egg-laying patterns. Here, we investigated diel changes in the egg-laying behaviour of a natural population of A. foliaceus. Data were collected from 17-28 May 2004. Days were divided into 3 time periods: 06:00-14:00, 14:00-22:00 and 22:00-06:00 h. Significantly more egg clutches were laid from 06:00-14:00 h than during the other 2 time periods, which were not significantly different from each other. Significantly more egg clutches per hour were laid during hours of daylight as compared to hours of darkness. Significantly more egg clutches were laid in the top 1 m of the water column than at the bottom, and this was consistent throughout all 3 time periods. It is suggested that the increase in egg-laying activity during daylight hours may be due to a higher motivation to search for hosts during the night and an increased ability to locate silhouetted egg-laying sites during the day. These data can provide information useful for egg removal and control strategies.

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Fucus and Laminaria species, dominant seaweeds in the intertidal and subtidal zones of the temperate North Atlantic, experience tidal cycles that are not synchronized with light:dark (L:D) cycles. To investigate how nutrient assimilation is affected by light cycles, the activity of nitrate reductase (NR) was examined in thalli incubated in outdoor tanks with flowing seawater and natural L:D cycles. NR activity in Laminaria digitata (Huds.) Lamour. showed strong diel patterns with low activities in darkness and peak activities near midday. This diel pattern was controlled by light but not by a circadian rhythm. In contrast, there was no diel variation in NR activity in Fucus serratus L., F. vesiculosus (L.) Lamour., and F. spiralis L. either collected directly from the shore or maintained in the outdoor tanks. In laboratory cultures, transfer to continuous darkness suppressed NR activity in L. digitata, but not in F. vesiculosus; continuous light increased NR activity in L. digitata but decreased activity in F. vesiculosus. Furthermore, 4 d enrichment with ammonium (50 mu mol . L-1 pulses), resulted in NR activity declining by > 80% in L. digitata, but no significant changes in F. serratus. Seasonal differences in maximum NR activity were present in both genera with activities highest in late winter and lowest in summer. This is the first report of NR activity in any alga that is not strongly regulated by light and ammonium. Because light and tidal emersion do not always coincide, Fucus species may have lost the regulation of NR by light that has been observed in other algae and higher plants.

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The Perils of Moviegoing in America is a film history that examines the various physical and (perceived) moral dangers facing audiences during the first fifty years of film exhibition.

Chapter 1: “Conflagration”
As early as 1897, a major fire broke out at a film exhibition in San Francisco, with flames burning the projectionist and nearby audience members. From that point until the widespread adoption of safety stock in 1950, fires were a very common movie-going experience. Hundreds of audience members lost their lives in literally thousands of theatre fires, ranging from early nickelodeons to the movie palaces of the thirties and forties.

Chapter 2: “Thieves Among Us”
Bandits robbed movie theatres on hundreds of occasions from the early days of film exhibition through the end of the Great Depression. They held up ticket booths, and they dynamited theatre safes. They also shot theatre managers, ushers, and audience members, as a great many of the robberies occurred while movies were playing on the screens inside.

Chapter 3: “Bombs Away”
Bombings at movie theatres became common in small towns and large cities on literally hundreds of occasions from 1914 to the start of World War II. Some were incendiary bombs, and some were stench bombs; both could be fatal, whether due to explosions or to the trampling of panicked moviegoers

Chapter 4: “It’s Catching”
Widespread movie-going in the early 20th century provoked an outcry from numerous doctors and optometrists who believed that viewing films could do irreparable harm to the vision of audience members. Medical publications (including the Journal of the American Medical Association) published major studies on this perceived problem, which then filtered into popular-audience magazines and newspapers.

Chapter 5: “The Devil’s Apothecary Shops”
Sitting in the dark with complete strangers proved worrisome for many early filmgoers, who had good reason to be concerned. Darkness meant that prostitutes could easily work in the balconies of some movie theatres, as could “mashers” who molested female patrons (and sometimes children) after the lights were dimmed. That was all in addition to the various murderers who used the cover of darkness to commit their crimes at movie theatres.

Chapter 6: “Blue Sundays”
Blue laws were those regulations that prohibited businesses from operating on Sundays. Most communities across the US had such legislation on their books, which by the nickelodeon era were at odds with the thousands of filmgoers who went to the movies every Sunday. Theatre managers were often arrested, making newspaper headlines over and over again. Police sometimes even arrested entire film audiences as accomplices in the Blue Law violations.

Chapter 7: “Something for Nothing”
In an effort to bolster ticket sales, many movie theatres in the 1910s began to hold lotteries in which lucky audience members won cash prizes; by the time of the Great Depression, lotteries like “Bank Night” became a common aspect of the theatre-going enterprise. However, reception studies have generally overlooked the intense (and sometimes coordinated) efforts by police, politicians, and preachers to end this practice, which they viewed as illegal and immoral gambling.

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Mechanisms for visuospatial cognition are often inferred directly from errors in behavioral reports of remembered target direction. For example, gaze-centered target representations for reach were first inferred from reach overshoots of target location relative to gaze. Here, we report evidence for the hypothesis that these gaze-dependent reach errors stem predominantly from misestimates of hand rather than target position, as was assumed in all previous studies. Subjects showed typical gaze-dependent overshoots in complete darkness, but these errors were entirely suppressed by continuous visual feedback of the finger. This manipulation could not affect target representations, so the suppressed gaze-dependent errors must have come from misestimates of hand position, likely arising in a gaze-dependent transformation of hand position signals into visual coordinates. This finding has broad implications for any task involving localization of visual targets relative to unseen limbs, in both healthy individuals and patient populations, and shows that response-related transformations cannot be ignored when deducing the sources of gaze-related errors.

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PURPOSE: To investigate the quality of life and priorities of patients with glaucoma.

METHODS: Patients diagnosed with glaucoma and no other ocular comorbidity were consecutively recruited. Clinical information was collected. Participants were asked to complete three questionnaires: EuroQuol (EQ-5D), time tradeoff (TTO), and choice-based conjoint analysis. The latter used five-attribute outcomes: (1) reading and seeing detail, (2) peripheral vision, (3) darkness and glare, (4) household chores, and (5) outdoor mobility. Visual field loss was estimated by using binocular integrated visual fields (IVFs).

RESULTS: Of 84 patients invited to participate, 72 were enrolled in the study. The conjoint utilities showed that the two main priorities were "reading and seeing detail" and "outdoor mobility." This rank order was stable across all segmentations of the data by demographic or visual state. However, the relative emphasis of these priorities changed with increasing visual field loss, with concerns for central vision increasing, whereas those for outdoor mobility decreased. Two subgroups of patients with differing priorities on the two main attributes were identified. Only 17% of patients (those with poorer visual acuity) were prepared to consider TTO. A principal component analysis revealed relatively independent components (i.e., low correlations) between the three different methodologies for assessing quality of life.

CONCLUSIONS: Assessments of quality of life using different methodologies have been shown to produce different outcomes with low intercorrelations between them. Only a minority of patients were prepared to trade time for a return to normal vision. Conjoint analysis showed two subgroups with different priorities. Severity of glaucoma influenced the relative importance of priorities.

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Positioned in relation to an emerging geographical interest into the effects of different atmospheric and observational conditions in shaping sensory engagements with the Earth's surfaces, this paper considers how a critical examination of the practices of camouflage can open up new dialogues into how the Earth's surfaces become known, are interacted with, and transformed in the conditions of darkness. With an empirical focus on the cultural and historical geographies of nocturnal camouflage practised during the Second World War, the paper examines the systematic attempts of civil camoufleurs to understand how natural and artificial landforms were visibly 'present' in the nocturnal landscape, despite darkness often being conceived as producing an environment of 'visual absence' through diminished sensory engagement. Furthermore, the paper highlights how the tensions between visual presence/absence that shape both the nocturnal experience and the 'knowing' of landscape can often be exploited for social, cultural, and political ends, in this case, to enable protection against aerial attack. © 2013 Pion and its Licensors.

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This paper considers the concept of light pollution and its connections to moral geographies of landscape in Britain. The paper aims to provide a greater understanding of light pollution in the present day, where the issue connects to policy debates about energy efficiency, crime, health, ecology and night time aesthetics, whilst also engaging with new areas of research in cultural geography. The main sources of investigation are the Campaign to Protect Rural England and the British Astronomical Association’s Campaign for Dark Skies (est. 1990). Using interviews, archival and textual analysis, the paper examines this anti-light-pollution lobby, looking at the lead-up to the formation of the Campaign as well as its ongoing influence. A moral geography of light pollution is identified, drawing on two interconnected discourses – a notion of the ‘astronomical sublime’ and the problem of urbanization. Whilst the former is often invoked, both through visual and linguistic means, by anti-light pollution campaigners, the latter is characterized as a threat to clear night skies, echoing earlier protests against urban sprawl. Complementing a growing area of research, the geographies of light and darkness, this paper considers the light pollution lobby as a way of investigating the fundamental relationship between humankind and the cosmos in the modern age.

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This paper studies the representation of suburbs as a place of anguish in the “Special Police” novels (Fleuve Noir publisher, Paris) by Frédéric Dard. This anxiety, it is argued, is what lends this collection of 25 novels some of their essential qualities, their unhealthy climate and absolute darkness. Dard’s suburbs fit into the traditions of realism; but the atmosphere, characters and plots owe to the American hardboiled school and like in film noir, space is stylized and dramatized, and often used to express a judgment of moral nature. Spatial representations in these novels are part of a critique of civilization and constitute a comment on the social modernization and public intervention in the development of the French territory in the postwar period. The novels written by Frédéric Dard from the mid-1950s to mid-1960s offer a profoundly original representation of suburban angst and what was not yet known at the time as the suburban malaise. Avoiding clichés and excessively connoted referential spaces, Dard anchor these noir novels he called “novels of the night” in landscapes that are both biographical and intertextual. The West Suburbs of Paris and what was
to become the Yvelines department are at the centre of Dard’s novelistic geography, turning into a mythical and deadly space in which is negotiated an acculturation in France of the evil and ruined world described in American noir.

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Background Entry into mitosis is regulated by cyclin dependent kinases that in turn are phosphoregulated. In most eukaryotes, phosphoregulation is through WEE1 kinase and CDC25 phosphatase. In higher plants a homologous CDC25 gene is unconfirmed and hence the mitotic inducer Schizosaccharomyces pombe (Sp) cdc25 has been used as a tool in transgenic plants to probe cell cycle function. Expression of Spcdc25 in tobacco BY-2 cells accelerates entry into mitosis and depletes cytokinins; in whole plants it stimulates lateral root production. Here we show, for the first time, that alterations to cytokinin and ethylene signaling explain the rooting phenotype elicited by Spcdc25 expression in Arabidopsis. Results Expressing Spcdc25 in Arabidopsis results in increased formation of lateral and adventitious roots, a reduction of primary root width and more isodiametric cells in the root apical meristem (RAM) compared with wild type. Furthermore it stimulates root morphogenesis from hypocotyls when cultured on two way grids of increasing auxin and cytokinin concentrations. Microarray analysis of seedling roots expressing Spcdc25 reveals that expression of 167 genes is changed by > 2-fold. As well as genes related to stress responses and defence, these include 19 genes related to transcriptional regulation and signaling. Amongst these was the up-regulation of genes associated with ethylene synthesis and signaling. Seedlings expressing Spcdc25 produced 2-fold more ethylene than WT and exhibited a significant reduction in hypocotyl length both in darkness or when exposed to 10 ppm ethylene. Furthermore in Spcdc25 expressing plants, the cytokinin receptor AHK3 was down-regulated, and endogenous levels of iPA were reduced whereas endogeous IAA concentrations in the roots increased. Conclusions We suggest that the reduction in root width and change to a more isodiametric cell phenotype in the RAM in Spcdc25 expressing plants is a response to ethylene over-production. The increased rooting phenotype in Spcdc25 expressing plants is due to an increase in the ratio of endogenous auxin to cytokinin that is known to stimulate an increased rate of lateral root production. Overall, our data reveal important cross talk between cell division and plant growth regulators leading to developmental changes.

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Drawing on ethnographic interviews with customers, this paper looks at the experience of dining at Dans le Noir?, a restaurant in London where eating is carried out in complete darkness. As an exemplary gastro-tourist site within the expanding leisure economy at which sensory alterity is sought, we argue that the transformation of the usual unreflexive habits of sensing while dining offer opportunities to encounter difference and reflect upon our culturally located ways of sensing the world. In focusing upon the altered experience of apprehending space, eating and socialising in the absence of light, we contend that this dining experience offers broader suggestions about how we might reconsider the qualities and potentialities of darkness, a condition which has been historically feared and reviled in the west.

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This paper aims at analysing the writing of the Portuguese author António Lobo Antunes, considered one of the major writers in European Literature with 26 books published, by focusing on the strategies deployed in his texts of creating micro-narratives within the main frame, and conveying the elements of individual and collective memory, past and present, the self and the others, using various voices and silences. Lobo Antunes incorporates in his writing his background as a psychiatrist at a Mental Hospital in Lisbon, until 1985 (when he decided to commit exclusively to writing), his experience as a doctor in the Portuguese Colonial War battlefield, but also the daily routines of the pre and post 25th of April 1974 (Portuguese Revolution) with subtle and ironic details of the life of the middle and upper class of Lisbon‘s society: from the traumas of the war to the simple story of the janitor, or the couple who struggles to keep their marriage functional, everything serves as material to develop and interweave a complex plot, that a lot of readers find too enwrapped and difficult to follow through. Some excerpts taken from his first three novels and books of Chronicles and his later novel – Ontem não te Vi em Babilónia (2006) – will be put forward to exemplify the complexity of the writing and the main difficulties of the reader, lost in a multitude of narrators‘ voices. Recently, Lobo Antunes has commented on his work stating: What I write can be read in the darkness. This paper aims at throwing some light by unfolding some of the strategies employed to defy new borders in the process of reading.

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Pelo menos a partir de Platão, o problema da “vontade de verdade” tornou-se um dos problemas filosóficos mais badalados do pensamento ocidental. A polémica e a tinta gasta à volta deste problema, a partir daí, foram mais que muitas. Desde a Antiguidade até aos séculos mais recentes o trabalho filosófico tenta e volta a tentar olhar para este problema. Muito resumidamente, o problema da “vontade de verdade” diz respeito à pergunta pela forma como está constituída a relação entre o homem e a verdade, i.e., entre o projecto vital humano e o seu projecto de conhecimento. Não deve causar espanto, por isso, que seja um dos problemas centrais da filosofia; está preso a duas questões essenciais do homem: a vida boa e a possibilidade de conhecer. As Confissões de Agostinho são um momento importante da discussão em torno do conceito de «vontade de verdade». Ao longo dos treze livros, Agostinho, que diz ter descoberto a verdade, parece situar-se numa posição impossível que se caracteriza pela radicalização tanto da necessidade de perseguição da “vontade de verdade” para alcançar a felicidade como pela radicalização do diagnóstico da profunda fragilidade do conhecimento humano. O objectivo deste estudo é mostar como tanto a identificação do homem com a ideia de “cor inquietum” como com a ideia de “cor contenebratum” se articula com a tese agostiniana de que se deve, a risco de todo o perigo, procurar a verdade.

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We conducted an experiment to assess the use of olfactory traces for spatial orientation in an open environment in rats, Rattus norvegicus. We trained rats to locate a food source at a fixed location from different starting points, in the presence or absence of visual information. A single food source was hidden in an array of 19 petri dishes regularly arranged in an open-field arena. Rats were trained to locate the food source either in white light (with full access to distant visuospatial information) or in darkness (without any visual information). In both cases, the goal was in a fixed location relative to the spatial frame of reference. The results of this experiment revealed that the presence of noncontrolled olfactory traces coherent with the spatial frame of reference enables rats to locate a unique position as accurately in darkness as with full access to visuospatial information. We hypothesize that the olfactory traces complement the use of other orientation mechanisms, such as path integration or the reliance on visuospatial information. This experiment demonstrates that rats can rely on olfactory traces for accurate orientation, and raises questions about the establishment of such traces in the absence of any other orientation mechanism. Copyright 1998 The Association for the Study of Animal Behaviour.

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The aim of the present study was to determine whether and how rats can use local olfactory cues for spatial orientation. Rats were trained in an eight-arm radial maze under different conditions as defined by the presence or absence of supplementary olfactory cues marking each arm, the availability of distant visuospatial information, and the illumination of the maze (light or darkness). The different visual conditions were designed to dissociate among the effects of light per se and those of visuospatial cues, on the use of olfactory cues for accurate arm choice. Different procedures with modifications of the arrangement of olfactory cues were used to determine if rats formed a representation of the spatial configuration of the olfactory cues and if they could rely on such a representation for accurate arm choice in the radial maze. The present study demonstrated that the use of olfactory cues to direct arm choice in the radial arm maze was critically dependent on the illumination conditions and implied two different modes of processing of olfactory information according to the presence or the absence of light. Olfactory cues were used in an explicit manner and enabled accurate arm choice only in the absence of light. Rats, however, had an implicit memory of the location of the olfactory cues and formed a representation of the spatial position of these cues, whatever the lighting conditions. They did not memorize the spatial configuration of the olfactory cues per se but needed these cues to be linked to the external spatial frame of reference.