Conditions For Visibility Research Articles

Ayo, Bisexual Check

Ayo, Bisexual Check

LGBT + academics’ and PhD students’ experiences of visibility in STEM: more than raising the rainbow flag

The experiences of lesbian, gay, bisexual, and transgender (LGBT +) individuals in Science, Technology, Engineering, and Mathematics (STEM) are still understudied and, despite some improvements, are still characterised by patterns of exclusion, disadvantage, and discrimination. In this article, we explore how visibility is perceived and navigated by LGBT + academics and PhD students in STEM, with a focus on the ways that interlocking systems of oppression impact people and groups who are marginalised and historically excluded. This article draws on a broader research project about the experiences of women and LGBT + people in STEM that was conducted between 2019 and 2020 at a UK university and is framed by intersectionality theory. Based on the thematic analysis of interviews and focus groups with 24 LGBT + participants, findings suggest that visibility is still a risk for LGBT + academics and PhD students in STEM. We found that the labour of navigating visibility was perceived as an unfair disadvantage and that the focus on individuals’ visibility in the absence of meaningful and transformative inclusion initiatives by higher education institutions was regarded as tokenistic. The article argues that addressing LGBT + visibility should firstly be an institutional responsibility and not an individual burden and that this work is essential to set the conditions for personal visibility to happen by choice, safely and without retribution.

Ancient didactic astronomical texts

The article focuses on ancient astronomy as an academic dis-cipline. Antiquity created a holistic image of the world and a cul-ture of thinking, in which the natural and exact sciences and lib-eral arts were not artificially differentiated and remained in har-monious unity, becoming the basis of an interdisciplinary ap-proach in education. Therefore, even the exact sciences were studied literarily from poetic works. On the example of ancient culture, the connection between the astronomical worldview and other components of the mindset is particularly clearly traced. This is crucial in terms of technology since ancient pedagogy contained all the criteria for technological effectiveness. In the Homeric age, the basic mnemonic rules for navigating by the stars, the definition of the conditions for visibility of heavenly bodies in all seasons, the connection of celestial phenomena with the calendar, known since the Cretan-Mycenaean age, were liter-arily recorded in the epic. This trend was further developed in Hesiod’s didactic epic and took shape in the content as a para-digm of astronomical education. The appearance of Cleobulina’s astronomical riddles appeared, which are allegorical in nature and show similarities with the allegories of Homer, took place approximately at the same time. In subsequent periods (from the 5th century BC), the school study of the Homer and Hesiod’s works required writing comments on the astronomical passages of these and later other authors. With the development of natural philosophical doctrines, new methods of presenting astronomical material appeared. The original form of the philosophical epic was replaced by a prosaic form. The reaction to the natural philo-sophical revolution led to a preference for the traditional Homer and Hesiod. Special educational astronomical texts written by such authors as Aratus, Germanicus, Alexander Aetolus, etc. came to exist-ence as a separate group.

Visibility of various road markings for machine vision

The same features of road markings – retroreflectivity and daytime visibility – are the key parameters for their recognition by both human drivers and for machine vision (MV) utilised by the emerging technology of automated vehicles. For the purpose of a side-by-side performance assessment of various road markings, 8 materials, differing in colour and retroreflectivity, were tested under laboratory conditions for visibility by LiDAR and by cameras under different weather conditions. Visibility was evaluated under various intensities of rain and fog; simulated effects of glare from oncoming vehicle were also tested. The response of MV equipment depended on (1) the equipment itself, (2) retroreflectivity of road marking, (3) their structure, (4) their colour, and (5) the utilised glass beads. Overall, the highest MV intensities were measured with structured cold plastic reflectorised with ‘premium’ glass beads (refractive index 1.6–1.7) and with white road marking tape. Unexpectedly, orange paint under dry conditions furnished LiDAR recognition disproportionally high to its retroreflectivity. Poorest outcome gave greyish paint imitating severely worn markings. During rain and during fog, use of the ‘premium’ glass beads resulted in significantly improved camera contrast ratio, but there was no such correlation with LiDAR intensity. On average, introduction of moisture lowered the measured contrast ratio by 80 % (range 69 %–86 %) and LiDAR response intensity by 84 % (range 72 %–96 %). Results from this case study can be used for development of road marking materials with improved recognition by MV.

Optimising graphene visibility in van der Waals heterostructures

Graphene constitutes one of the key elements in many functional van der Waals heterostructures. However, it has negligible optical visibility due to its monolayer nature. Here we study the visibility of graphene in various van der Waals heterostructures and include the effects of the source spectrum, oblique incidence and the spectral sensitivity of the detector to obtain a realistic model. A visibility experiment is performed at different wavelengths, resulting in a very good agreement with our calculations. This allows us to reliably predict the conditions for better visibility of graphene in van der Waals heterostructures. The framework and the codes provided in this work can be extended to study the visibility of any 2D material within an arbitrary van der Waals heterostructure.

Broken-line Markings Preferred Under High-speed Conditions for Visibility

Broken-line markings on the freeway have been installed for delineation and lane division, which together are expected to potentially reduce the number of traffic crashes. Although these functions are clearly dependent on visibility, the practical application of broken lines differs greatly worldwide in terms of the ratio of the line segment to the gap length or the width of the markings. On Korean freeways, existing broken-line markings consist of 8-m line segments and a 12-m gap with a width of 15 cm, although the reasoning for these dimensions is not known. The present study began with the field installation of diverse broken-line marking alternatives under the regulated ratio of the line segment to the gap segment—that is, 1:2 in Korea. Using the installed markings, a visibility experiment with subjects riding in a vehicle moving at a speed of 100 km/h was performed. From this study, it can be concluded that the existing broken-line markings on Korean freeways are not ideal in terms of visibility and that broken-line markings with 6-m line segments and a 12-m gap with a width of 13 cm is preferred in terms of visibility. This alternative was recommended to later become the new nationwide standard for Korean freeways.

Assessing different components of three-dimensional forest structure with single-scan terrestrial laser scanning: A case study

Efficient quantification of the three-dimensional forest structure is of increasing importance for our understanding of forest functions and services, but it remains challenging with conventional methods. We used a single-scan ground-based laser approach in stands with a known difference in management history and associated differences in structures. The data were used to test whether the measurement approach could distinguish various structural measures among the stands, including overall density, vertical structure, competitive conditions for regeneration, horizontal visibility, and three-dimensional structural variability. In general, our data reflected known differences in stand structure. However, in some cases the different measures showed contradicting results, highlighting the limited information represented in each measure when considered in isolation. At the same time, our results suggested that all components of stand structure do not develop in sync. The variability of horizontal and vertical structural heterogeneity appears to be a good indicator of structural elements typically found in old-growth forests, i.e., spatially homogenous (scale independent) horizontal structural variability in combination with a scale-dependent vertical structural variability. In addition, our results provided information with direct management implications. For example, gap creation, a prominent practice in restoration treatments in the region, increased spatial variability, but the hard edges and removal of all trees inside the gap, are not reflecting structural conditions found in our old-growth stand. In summary, our results suggest that this new technology can efficiently provide objective and holistic inventories of stand structures. However, more work is needed to fully understand the implications of the novel structural measures for ecosystem processes and services.

O SISTEMA DE JUSTIÇA PENAL ENTRE A INVISIBILIDADE PÚBLICA E O RECONHECIMENTO NA MODERNIDADE PERIFÉRICA

Diante das aparentes contradições do discurso punitivo da modernidade, fundador do processo penal e das tensões entre emancipação e regulação que caracterizam o Direito e o Judiciário modernos, espaços públicos supostamente destinados ao reconhecimento dos indivíduos, pretende-se discutir se o sistema de justiça criminal e, em especial, o processo penal, podem assegurar aos indivíduos as condições necessárias à afirmação da visibilidade e do reconhecimento. A partir do método dialético, defende-se a tese de que o processo penal da modernidade e, em especial, o sistema de justiça penal brasileiro, são incompatíveis com o reconhecimento intersubjetivo em razão de um obstáculo epistemológico, que serve ao mesmo tempo de mecanismo eficiente de consolidação da invisibilidade pública e de humilhação social.

Study on optical interference effect of graphene oxide films on SiO2 and Si3N4 dielectric films

The optical interference effect has enabled the visualization of thin layers, even monolayers, of graphene by simple optical microscopy. In this study, we have controlled the optical interference effect by changing the thickness and types of dielectric films, i.e. SiO2 and Si3N4. By investigating differences in RGB parameters between the graphene oxide layer and the dielectric layer, conditions for the highest visibility of the graphene oxide layer were determined. We also studied colors as a function of graphene oxide layer thickness and dielectric layer thickness. These color patterns can be effectively presented as two-dimensional color charts. When comparing SiO2 and Si3N4 as dielectric layers, each layer was found to exhibit different interference fringe patterns, which is due to a mismatch of optical properties between the material layer and dielectric layer. The effects of optical properties (n, k) of the material layer on interference colors were also investigated.

Visible Signatures of Hypersonic Reentry

Aerothermal heating of hypersonic reentry bodies can generate significant radiation of visible light. This study investigates the conditions for ground-level visibility and what the authors term noticeability of that radiated light to the unaided human eye. This study considers radiated visible light, transmission to ground level as a function of relative observer position, sky background contrast, human contrast perception limits, and psychophysical considerations for attention capture. Considering both pure ballistic trajectories and lifting-body trajectories, this study presents examples of spatial and temporal viewing zones for both detectability and noticeability. In some cases, viewing zones extend a significant distance from the impact location and/or include the impact location for a potentially significant period of time before impact.

Vision-based control for rigid body stabilization

This paper addresses the problem of stabilizing to a desired equilibrium point an eye-in-hand system, which consists of a single camera mounted on a rigid body free to move on SE ( 3 ) . It is assumed that there is a collection of landmarks fixed in the environment and that the image coordinates of those landmarks are provided to the system by an on-board CCD camera. The proposed method addresses not only the problem of stabilization but also that of maintaining feature visibility along the system’s trajectory. The resulting solution consists of a feedback control law based on the current and desired image coordinates and reconstructed attitude and depth ratio information, which guarantees that (i) the desired equilibrium point is an almost global attractor; (ii) a set of necessary conditions for feature visibility holds throughout the system’s trajectories; and (iii) the image of a predefined feature point is kept inside the camera’s field of view.

AISI 304 stainless steel marking by a Q-switched diode pumped Nd:YAG laser

Abstract Laser marking tests were carried out on AISI 304 steel, using a Q-switched diode pumped Nd:YAG laser. The aim was to determine the correlation occurring between working parameters (i.e. pulse frequency, beam scanning speed, and current intensity) and resulting mark visibility. The latter was evaluated as the contrast index measured from digital images of the marks. To characterize mark features, its width and roughness were estimated, and analyses employing optical and scanning electron microscopy coupled with energy dispersive X-ray technique were carried out. From the experimental results, both surface roughness and oxidation increased as a function of frequency, resulting in an improvement in contrast, up to a characteristic value, decreasing afterwards. Besides, the maximum visibility value was beneficially affected by lower scanning speeds and lower current intensities. An empirical model was built, and from it the best processing conditions for optimum mark visibility, taking into account the operating constraints of the laser system used, were drawn.

Characterization of defect structures in magnetic liquid encapsulated Kyropoulos grown InP single crystals

Synchrotron White Beam X-ray Topography (SWBXT) has been used as a nondestructive diagnostic technique for the characterization of defect structures in large wafers cut from S and Fe-doped InP single-crystal boules. Wafers cut both longitudinally and laterally with respect to the growth axis were studied in order to reveal the overall defect distribution in the boules. Studies carried out on longitudinally cut S-doped crystals enabled information to be obtained on interface shape, from the observation of growth striations, as well as defect distribution. The conditions for optimal visibility of the growth striations were determined and it was found that the morphology of the growth interface was a sensitive function of local growth conditions. The formation of extensive slip bands from peripheral regions was also observed. This indicates that large thermal stresses were generated during crystal growth leading to such significant plastic deformation processes. Studies carried out on a series of laterally sliced, Fe-doped wafers cut from the same boule revealed dislocations in well-defined fourfold symmetric distributions. A finite element thermal-elastic stress analysis was performed for an intermediate growth stage to investigate the nature of the stress which causes this fourfold distribution. The calculated excess shear stress from this analysis agrees qualitatively with the observed dislocation distribution and slip system activity. The influence of an applied magnetic field on precipitate distributions in InP boules was preliminarily studied by examining a longitudinal cut, heavily Fe-doped InP wafer, which was grown in the presence of an intermittent applied field. Topographs recorded from this wafer revealed that no formation of large precipitates was discernible in either the initial or intermediate growth stages when the magnetic field was applied. On the other hand, the formation of large precipitates was observed in regions near the final stage of crystal growth when the magnetic field was turned off. Further such investigations are underway.

"Event-ready-detectors" Bell experiment via entanglement swapping.

Using independent sources one can realize an ``event-ready'' Bell--Einstein-Podolsky-Rosen experiment in which one can measure directly the probabilities of the various outcomes including nondetection of both particles. Our proposal involves two parametric down-converters. Subcoherence-time monitoring of the idlers provides a noninteractive quantum measurement entangling and preselecting the independent signals without touching them. We give the conditions for high fringe visibility and particle collection efficiency as required for a Bell test.

The use of SPOT data for wave analysis

After recalling the various techniques used for wave measurement, this paper concentrates on the possibilities of using SPOT data for large scale wave analysis. Conditions for good wave pattern visibility are discussed from a theoretical point of view. In order to check the theory, examination of a large number of SPOT images was performed concerning the relation between viewing conditions and image quality. Using spectral analysis, a comparison is achieved using available simultaneous in situ directional data and SPOT images of an off shore area in Brittany, France. Major conclusions are that both types of data compare rather well and that SPOT data could be used effectively in the coastal zone, provided that a proper software is designed to process small spatial windows. Recommendations are given for image acquisition procedure.

On the nature and visibility of crater-associated streaks on Mars

R. O. Kuzmin has proposed that all crater-associated wind streaks on Mars are depositional and consist of unresolved barchan-like dunes. He claims that any streak can appear either bright or dark relative to its surroundings depending on the azimuth of the Sun relative to the streak axis and on the elevation of the Sun above the horizon. Our studies of the entire Mariner 9 picture collection as well as of available Viking data lend no support to these ideas. We find that the conditions for visibility of bright and dark streaks are identical. In Mariner 9 images both types of streaks are visible for viewing angles ϵ ⪅ 60°, illumination angles of 15° ⪅ i ⪅ 75°, and over the whole range of phase angles covered (about 15 to 85°). There are numerous examples of dark and light streaks visible at the same azimuth angle of the Sun, contrary to Kuzmin's claim. There is much evidence to indicate that bright and dark streaks differ both in morphology and in character. The common ragged dark streaks are probably erosion scars, while most bright streaks probably represent accumulations of bright dust-storm fallout. There is no evidence at present that these accumulations have a barchan-like texture.

Some day and night visual aspects of motorcycle safety : Woltman, H.L. and Austin, R.L. Transportation Research Record, 1974, No 502, 1–8

This study includes a comparison of the daylight visibility properties of 2 flourescent and 4 conventional pigments against representative backgrounds for clear and overcast sky conditions, representative solar altitudes, and cardinal directions. In detection and identification, fluorescents are comparable to conventional high-visibility pigments under optimum viewing conditions; however, fluorescents show a substantial improvement when illumination levels decrease toward dusk or when conditions for visibility are least advantageous. As a result, fluorescent colors are now used for certain safety applicances and devices where particularly hazardous conditions are common. Aspects of night visibility suffer from extremes of contrast, low levels of available light, and ineffectiveness of any conventional color to render objects visible at night. Visual clues are dependent on learned patterns of light sources rather than on natural information acquired from daytime driving. Transferral of visual skills from day to night is substantially inhibited by the widely differing aspects unless some natural' visual information is preserved. The night factors and materials that tend to visually preserve nature information have long been employed for traffic signs and safety appliances. Their extension to cyclist and vehicular use is a promising means of enhancing rapid night visual comprehension. A systemized means of evaluating both the day and night aspects of the visual elements comprising the motorcycle and cyclist is presented. A perception model is reviewed as a possible means of evaluating the several aspects of the visual model.

The detection of submicroscopic lattice defects in aluminium utilizing a vacancy supersaturation

The conditions under which submicroscopic defects can be revealed due to decoration by the precipitation of vacant lattice sites from a supersaturated solution have been investigated in aluminium. It is shown that quench temperature, specimen purity and other conditions have to be so chosen that the nucleation of self-sinks is minimized while an adequate vacancy supersaturation is maintained. The conditions for the optimum visibility of defects revealed in this way have been studied primarily by observing the variation in the density of rows of dislocation loops along <110> directions. This decoration technique has been used in quenched single crystals deformed in single slip to show that these rows and also narrow faulted dislocation dipoles with their long axes in the <110> direction form along the specific <110> direction predicted from a hypothesis involving the dragging of a jog by a moving screw dislocation.

Interferometric Measurement of Wave-Front Aberrations in Gratings and Echelles*

Modern production of diffraction gratings requires rapid and reliable methods of evaluating quantitatively the wave fronts produced, to determine errors in blank figure and groove positioning. Comparison of methods, including cross ruling, moiré patterns with replicas, Foucault knife-edge tests, phase contrast determinations, and various types of interferometry, supplemented by determinations of ghost intensities, indicates that for errors greater than about λ/40, comparison of the wave front with that from a reference mirror in a Michelson interferometer used in the Twyman-Green manner gives the most nearly adequate conditions for good visibility and sensitivity. Tests at great diffraction angles, necessary for high sensitivity, give patterns of higher contrast and greater intensity than those obtained with the Fizeau plano-interferometer. Exposure times of 10 sec give all needed information about errors.Analysis of the straight-line fringe system obtained shows that in a given order m, a spacing error expressed in fringes is given by Δa=a/m per fringe deviation in the interference pattern, if the spacing constant a is also expressed in fringes. The spacing error per fringe aberration in the interferometer has the same absolute value for all gratings and echelles, irrespective of their spacing constant, provided that the interferograms are taken at the same angle of incidence, and in light of the same wavelength. This provides an important way of directly comparing the quality of various diffraction instruments, and of estimating their intrinsic resolving powers separate from the aberrations of other components of the spectrograph, which affect the limit of resolution.Uniqueness of interpretation of the interferograms can be ascertained by taking interferograms of the same grating area in two suitably selected orders, with a graduated reference scale placed directly on the grating surface showing in both.

RELATION BETWEEN ILLUMINATION AND VISUAL EFFICIENCY

THE<i>British Medical Journal</i>recently carried an annotation under the title "Conditions for Good Visibility,"¹based on investigations made by H. C. Weston at the National Physics Laboratory under the auspices of the Illumination Research Council and published by the Industrial Health Research Board of the Medical Research Council. Weston's investigation was intended to test the value of a method suggested by Beutell²for determining the level of illumination required for the efficient performance of any kind of work involving visual discrimination. The method is based on the proposition that the illumination required for any visual task, as compared with the simplest possible task, depends on certain conditions adversely affecting its performance, that these conditions can be defined and that if the relationship can be ascertained between each of the conditions and the illumination required to compensate for it then the illumination suitable for the performance of the