363 research outputs found

    The effects of glare and inhomogeneous visual fields on contrast detection in the context of driving

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    An experiment was carried out to investigate how contrast threshold for target detection is affected by the presence of glare and by extraneous light sources using the method of ascending limits. The target was located at either a foveal or a peripheral (10° right) location, glare was adjacent to the foveal location, simulating the headlamps of an oncoming vehicle, and extraneous light sources were at either foveal or peripheral (10° right or left) locations. Contrast threshold for a foveal target without glare was affected mainly by the surrounding local luminance distribution. However, in the presence of glare and also for the peripheral target (both with and without glare) the global luminance distribution matters. Glare increased the contrast needed for detection of the foveal target, but this effect was reduced by the presence of extraneous light sources that were peripheral to the target. For peripheral targets, contrast threshold was also reduced by the presence of extraneous light at a non-target location and this effect was increased in the presence of glare. Glare equations tend to be based on tests using uniform, homogenous fields: these data indicate that, in the presence of extraneous light sources, the influence of glare is over-estimated

    ColorPhylo: A Color Code to Accurately Display Taxonomic Classifications

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    Color may be very useful to visualise complex data. As far as taxonomy is concerned, color may help observing various species’ characteristics in correlation with classification. However, choosing the number of subclasses to display is often a complex task: on the one hand, assigning a limited number of colors to taxa of interest hides the structure imbedded in the subtrees of the taxonomy; on the other hand, differentiating a high number of taxa by giving them specific colors, without considering the underlying taxonomy, may lead to unreadable results since relationships between displayed taxa would not be supported by the color code. In the present paper, an automatic color coding scheme is proposed to visualise the levels of taxonomic relationships displayed as overlay on any kind of data plot. To achieve this goal, a dimensionality reduction method allows displaying taxonomic “distances” onto a Euclidean two-dimensional space. The resulting map is projected onto a 2D color space (the Hue, Saturation, Brightness colorimetric space with brightness set to 1). Proximity in the taxonomic classification corresponds to proximity on the map and is therefore materialised by color proximity. As a result, each species is related to a color code showing its position in the taxonomic tree. The so called ColorPhylo displays taxonomic relationships intuitively and can be combined with any biological result. A Matlab version of ColorPhylo is available at http://sy.lespi.free.fr/ColorPhylo-homepage.html. Meanwhile, an ad-hoc distance in case of taxonomy with unknown edge lengths is proposed

    Review of a published article (Kakitsuba N. Comfortable Indoor Lighting Conditions Evaluated from Psychological and Physiological Responses.)

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    This note is a critical review of the spatial brightness experiment reported by Kakitsuba [Kakitsuba 2015]. There are several reasons why I think the study is flawed and therefore that the results should not be considered credible. In particular, the results can largely be explained by a stimulus range bias, the ‘boundary’ illuminances tending to lie near the centre of each range of illuminances reported. Therefore the results are a product of the illuminance ranges chosen by the experimenter and do not indicate observers’ preferences for light level

    Second harmonic generation: Goursat problem on the semi-strip and explicit solutions

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    A rigorous and complete solution of the initial-boundary-value (Goursat) problem for second harmonic generation (and its matrix analog) on the semi-strip is given in terms of the Weyl functions. A wide class of the explicit solutions and their Weyl functions is obtained also.Comment: 20 page

    Diversity of Mobile Genetic Elements in the Mitogenomes of Closely Related Fusarium culmorum and F. graminearum sensu stricto Strains and Its Implication for Diagnostic Purposes

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    Much of the mitogenome variation observed in fungal lineages seems driven by mobile genetic elements (MGEs), which have invaded their genomes throughout evolution. The variation in the distribution and nucleotide diversity of these elements appears to be the main distinction between different fungal taxa, making them promising candidates for diagnostic purposes. Fungi of the genus Fusarium display a high variation in MGE content, from MGE-poor (Fusarium oxysporum and Fusarium fujikuroi species complex) to MGE-rich mitogenomes found in the important cereal pathogens F. culmorum and F. graminearum sensu stricto. In this study, we investigated the MGE variation in these latter two species by mitogenome analysis of geographically diverse strains. In addition, a smaller set of F. cerealis and F. pseudograminearum strains was included for comparison. Forty-seven introns harboring from 0 to 3 endonucleases (HEGs) were identified in the standard set of mitochondrial protein-coding genes. Most of them belonged to the group I intron family and harbored either LAGLIDADG or GIY-YIG HEGs. Among a total of 53 HEGs, 27 were shared by all fungal strains. Most of the optional HEGs were irregularly distributed among fungal strains/species indicating ancestral mosaicism in MGEs. However, among optional MGEs, one exhibited species-specific conservation in F. culmorum. While in F. graminearum s.s. MGE patterns in cox3 and in the intergenic spacer between cox2 and nad4L may facilitate the identification of this species. Thus, our results demonstrate distinctive traits of mitogenomes for diagnostic purposes of Fusaria

    Diversity of mobile genetic elements in the mitogenome of closely related Fusarium culmorum and F. graminearum sensu stricto strains ans its implication for diagnostic purposes

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    Much of the mitogenome variation observed in fungal lineages seems driven by mobile genetic elements (MGEs), which have invaded their genomes throughout evolution. The variation in the distribution and nucleotide diversity of these elements appears to be the main distinction between different fungal taxa, making them promising candidates for diagnostic purposes. Fungi of the genus Fusarium display a high variation in MGE content, from MGE-poor (F. oxysporum and Fusarium fujikuroi species complex) to MGE-rich mitogenomes found in the important cereal pathogens F. culmorum and F. graminearum sensu stricto. In this study, we investigated the MGE variation in these latter two species by mitogenome analysis of geographically diverse strains. In addition, a smaller set of F. cerealis and F. pseudograminearum strains was included for comparison. Forty-seven introns harboring from 0 to 3 endonucleases (HEGs) were identified in the standard set of mitochondrial protein-coding genes. Most of them belonged to the group I intron family and harbored either LAGLIDADG or GIY-YIG HEGs. Among a total of 53 HEGs, 27 were shared by all fungal strains. Most of the optional HEGs were irregularly distributed among fungal strains/species indicating ancestral mosaicism in MGEs. However, among optional MGEs, one exhibited species-specific conservation in F. culmorum. While in F. graminearum s.s. MGE patterns in cox3 and in the intergenic spacer between cox2 and nad4L may facilitate the identification of this species. Thus, our results demonstrate distinctive traits of mitogenomes for diagnostic purposes of Fusaria.Fil: Kulik, Tomasz. Department Of Botany And Nature Protection, University; PoloniaFil: Brankovics, Balazs. Wageningen Plant Research, Wageningen University; PaĂ­ses BajosFil: Van Diepeningen, Anne D.. Waneningen Plant Research; PaĂ­ses BajosFil: Bilska, Katarzyna. Department Of Botany And Nature Protection, University; PoloniaFil: Zelechowski, Maciej. Department Of Botany And Nature Protection, University; PoloniaFil: MyszczyƄski, Kamil. Department Of Botany And Nature Protection, University; PoloniaFil: Molcan, Tomasz. Faculty Of Biology And Biotechnology, University; PoloniaFil: Stakheev. Alexander. Institute Of Bioorganic Chemistry (ras); RusiaFil: Stenglein, Sebastian Alberto. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro Cientifico TecnololĂłgico Mar del Plata. Instituto de Investigaciones en Biodiversidad y BiotecnologĂ­a. Laboratorio de BiologĂ­a Funcional y BiotecnologĂ­a; ArgentinaFil: Beyer, Marco. Luxembourg Institute Of Science And Technology; LuxemburgoFil: Pasquali, Matias. Faculty Of Agricultural And Food Sciences; ItaliaFil: Sawicki, Jakub. Department Of Botany And Nature Protection, University; PoloniaFil: Baturo Cieƛniewska, Anna. Baturo-cieśniewska; Poloni

    Advances in multispectral and hyperspectral imaging for archaeology and art conservation

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    Multispectral imaging has been applied to the field of art conservation and art history since the early 1990s. It is attractive as a noninvasive imaging technique because it is fast and hence capable of imaging large areas of an object giving both spatial and spectral information. This paper gives an overview of the different instrumental designs, image processing techniques and various applications of multispectral and hyperspectral imaging to art conservation, art history and archaeology. Recent advances in the development of remote and versatile multispectral and hyperspectral imaging as well as techniques in pigment identification will be presented. Future prospects including combination of spectral imaging with other noninvasive imaging and analytical techniques will be discussed

    Specifying enough light to feel reassured on pedestrian footpaths

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    This article discusses lighting for pedestrians and how investigation of reassurance might lead toward an understanding of the right amount of light. A conventional approach is to evaluate reassurance after dark under road lighting of different illuminance: this tends to show the trivial result that higher illuminances enhance reassurance, and that alone does not enable an optimum light level to be identified. One reason is that the category rating procedure widely used is prone to stimulus range bias; experimental results are presented that demonstrate stimulus range bias in reassurance evaluations. This article also recommends alternative methods for future research. One such method is the day–dark rating approach, which does not tend toward ever higher illuminances, and results are presented of two studies using this method

    Recruitment Potential of a Green Alga Ulva flexuosa Wulfen Dark Preserved Zoospore and Its Development

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    The recruitment potential and the ability of Ulva flexuosa Wulfen zoospores to survive darkness were tested under different conditions in the present study. The dark preserved zoospore was cultured under a two-factor experimental design to test the effect of salinity and nitrate, effect of salinity and phosphate, effect of light and salinity, and effect of light and phosphate. The recruitment (germination and growth) of zoospores was significantly affected by light and salinity. The nitrate concentration of 20 ”mol.l−1 was found to initiate the process of germination and its subsequent growth and, its effect appeared greatest under 25 psu condition. While nitrate enhances the growth of biomass more than phosphate, both show a positive interactive effect on biomass increase when crossed with salinity. The combined effect of 25 psu salinity and 8 ”mol.l−1 phosphate exhibited higher biomass growth. There was a significant effect of light and salinity on the biomass of zoospore, though there was no significant interaction between the two factors. There was an increase in biomass of growing zoospores to increase in light intensity and 80 ”mol.m−2.s−1 of light intensity was considered optimal. Similarly, high light intensity condition favored higher biomass growth and there was significant interaction between light (80 ”mol. m−2. s−1) and phosphate (4 ”mol. l−1) in high salinity (35 psu) condition. The result of this study showed that dark preserved zoospores of U. flexuosa have the potential for recruitment and it gives us an understanding how different factors play a role in the process of recruitment
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