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1.
Angew Chem Int Ed Engl ; 60(17): 9379-9383, 2021 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-33590640

RESUMO

Charge-recombination processes are critical for photovoltaic applications and should be suppressed for efficient charge transport. Here, we report that an applied magnetic field (0-1 T) can be used control the charge-recombination dynamics in an expanded rosarin-C60 complex. In the low magnetic field regime (<100 mT), the charge-recombination rate slows down due to hyperfine coupling, as inferred from transient absorption spectroscopic analyses. In contrast, in the high field regime, i.e., over 500 mT, the charge-recombination rate recovers and increases because the Δg mechanism facilitates spin conversion to a triplet charge-separated state (S to T0 ) that undergoes rapid charge-recombination to a localized rosarin triplet state. Therefore, we highlight the charge-recombination rate and the localized triplet state population can be modulated by the magnetic field in charge donor/acceptor non-covalent complexes.

2.
J Vis ; 21(2): 7, 2021 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-33576764

RESUMO

We examined whether perception of color saturation and lightness depends on the three-dimensional (3D) shape and surface gloss of surfaces rendered to have different hues. In Experiment 1, we parametrically varied specular roughness of predominantly planar surfaces with different mesoscopic relief heights. The orientation of surfaces was varied relative to the light source and observer. Observers matched perceived lightness and chroma (effectively saturation) using spherical objects rendered using CIE LCH color space. We observed strong interactions between perceived saturation and lightness with changes in surface orientation and surface properties (specular roughness and 3D relief height). Declines in saturation and increases in lightness were observed with increasing specular roughness. Changes in relief height had greater effects on perceived saturation and lightness for blue hues compared with reddish and greenish hues. Experiment 2 found inverse correlations between perceived gloss and specular roughness across conditions. Experiment 3 estimated perceived specular coverage and found that a weighted combination of perceived gloss and specular coverage could account for perceived color saturation and lightness, with different coefficients accounting for the perceptual experience for each of the three hue conditions. These findings suggest that perceived color saturation and lightness depend on the separation of specular highlights from diffuse shading informative of chromatic surface reflectance.

3.
Invest Ophthalmol Vis Sci ; 62(2): 4, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33533880

RESUMO

Purpose: Leading causes of irreversible blindness such as age-related macular degeneration (AMD) and glaucoma can, respectively, lead to central or peripheral vision loss. The ability of sufferers to process visual motion information can be impacted even during early stages of eye disease. We used head-mounted display virtual reality as a tool to better understand how vision changes caused by eye diseases directly affect the processing of visual information critical for self-motion perception. Methods: Participants with intermediate AMD or early manifest glaucoma with near-normal visual acuities and visual fields were recruited for this study. We examined their experiences of self-motion in depth (linear vection), spatial presence, and cybersickness when viewing radially expanding patterns of optic flow simulating different speeds of self-motion in depth. Viewing was performed with the head stationary (passive condition) or while making lateral-sway head movements (active conditions). Results: Participants with AMD (i.e., central visual field loss) were found to have greater vection strength and spatial presence, compared to participants with normal visual fields. However, participants with glaucoma (i.e., peripheral visual field loss) were found to have lower vection strength and spatial presence, compared to participants with normal visual fields. Both AMD and glaucoma groups reported reduced severity in cybersickness compared to healthy normals. Conclusions: These findings strongly support the view that perceived self-motion is differentially influenced by peripheral versus central vision loss, and that patients with different visual field defects are oppositely biased when processing visual cues to self-motion perception.

4.
J Phys Chem A ; 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33439653

RESUMO

We investigated the potential of chromophore's rotations to tune singlet fission (SF) kinetics in perylene bisimide (PBI) dimers in addition to relative horizontal displacements. The total number of 250 PBI dimers (five displacements along the long and short axis of PBI, respectively, and ten rotation angle changes from parallel to perpendicular alignment) was examined. Ground-state energies showed that dimer formation is favored in all orientations with some differences in interaction strength. Time-dependent density functional theory predicted S1 and T1 excitons' energy, and the thermodynamic feasibility of SF process was judged by the energy difference between a S1 exciton and twice of T1 excitons. In addition, we also estimated the relative rate of multiexciton generation step by the three-state kinetic model with the results of restricted active space employing double spin-flip. Nine promising orientations including two parallel PBI dimers and seven twisted ones were discussed. Wave function composition analysis showed that SF occurs mainly through the superexchange mechanism in various twisted PBI dimers, but the direct two-electron and coherent pathway could be operative at the particular positions. Quantum chemical simulations suggested the rotation as an effective tool to tune SF efficiency in PBI dimers, which is helpful to substantiate more efficient SF material.

5.
Appl Ergon ; 92: 103355, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33444884

RESUMO

This study investigated the effects of simulating self-motion via a head-mounted display (HMD) on standing postural sway and spatial presence. Standing HMD users viewed simulated oscillatory self-motion in depth. On a particular trial, this naso-occipital visual oscillation had one of four different amplitudes (either 4, 8, 12 or 16 m peak-to-peak) and one of four different frequencies (either 0.125, 0.25, 0.5 or 1 Hz). We found that simulated high amplitude self-oscillation (approximately 16 m peak-to-peak) at either 0.25 Hz or 0.5 Hz: 1) generated the strongest effects on postural sway; and 2) made participants feel more spatially present in the virtual environment. Our findings provide insight into the parameters of simulated self-motion that generate the strongest postural responses within virtual environments. These postural constraints have valuable implications for improving our understanding of sensory processes underlying the ergonomic experience of virtual environments simulated using HMDs.

6.
Angew Chem Int Ed Engl ; 59(47): 20956-20964, 2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-32633897

RESUMO

Singlet fission in organic semiconducting materials has attracted great attention for the potential application in photovoltaic devices. Research interests have been concentrated on identifying working mechanisms of coherent SF processes in crystalline solids as ultrafast SF is hailed for efficient multiexciton generation. However, as long lifetime of multiexcitonic triplet pair in amorphous solids facilitates the decorrelation process for triplet exciton extractions, a precise examination of incoherent SF processes is demanded in delicate model systems to represent heterogeneous structures. Heterogeneous coupling and energetics for SF were developed in our oligoacene dendrimers, which mimic complicated SF dynamics in amorphous solids. SF dynamics in dendritic structures was thoroughly investigated by time-resolved spectroscopic techniques and quantum chemical calculations in respect of the relative orientation/distance between chromophores and though-bond/-space interactions.

7.
Angew Chem Int Ed Engl ; 59(39): 16989-16996, 2020 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-32558161

RESUMO

Upon photon absorption, π-conjugated organics are apt to undergo ultrafast structural reorganization via electron-vibrational coupling during non-adiabatic transitions. Ultrafast nuclear motions modulate local planarity and quinoid/benzenoid characters within conjugated backbones, which control primary events in the excited states, such as localization, energy transfer, and so on. Femtosecond broadband fluorescence upconversion measurements were conducted to investigate exciton self-trapping and delocalization in cycloparaphenylenes as ultrafast structural reorganizations are achieved via excited-state symmetry-dependent electron-vibrational coupling. By accessing two high-lying excited states, one-photon and two-photon allowed states, a clear discrepancy in the initial time-resolved fluorescence spectra and the temporal dynamics/spectral evolution of fluorescence spectra were monitored. Combined with quantum chemical calculations, a novel insight into the effect of the excited-state symmetry on ultrafast structural reorganization and exciton self-trapping in the emerging class of π-conjugated materials is provided.

8.
Front Psychol ; 11: 485, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32265792

RESUMO

This study examined perceptual differentiation of specular from diffuse shading for the recovery of surface color and gloss. In Experiment 1, we parametrically varied the mesoscale relief height of globally planar surfaces, specular sharpness and the orientation of the surface relative to the light source. We obtained psychophysical matches for perceived color saturation and value (HSV), but also considered whether the main effects could be influenced by color space used when transforming data to perceptually-uniform CIE LCH space. Results revealed strong interactions between perceived color attributes and the lighting conditions, the structure of specular reflections, and surface relief. Declines in saturation were observed with increasing specular roughness (using an HSV color representation), but no similar decline was observed in chroma (using a CIE LCH color representation). Experiment 2 found strong negative correlations between perceived gloss and specular roughness. Perceived gloss also depended on mesoscopic relief height and orientation of the surface relative to the light source. Declines in perceived gloss moderately accounted for the variability in color saturation and value matches obtained in Experiment 1. We found information about perceived specular coverage could further improve the model's accountability of perceived color saturation and lightness (Experiment 3). These findings together suggest that perceived color saturation and color value depends on the visual system's ability to distinguish the underlying diffuse shading from specular highlights in images.

9.
J Am Chem Soc ; 142(17): 7845-7857, 2020 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-32267155

RESUMO

The singlet fission (SF) process is generally defined as the conversion of one singlet exciton (S1) into two triplet excitons (2·T1), which has the potential to overcome thermalization losses in the field of photovoltaic devices. Among the applicable compounds for SF-based photovoltaic devices, perylene bisimide (PBI) is one of the best candidates because of its electronic tunability and photostability. However, the strategy for efficient SF in PBIs remains ambiguous because of numerous competing relaxation pathways in PBI-based molecular materials. In this regard, for the first time, we observed the SF mechanism in PBI dimers by controlling the intrinsic factor (exciton coupling) and the external environment (solvent polarity and viscosity). Time-resolved spectroscopic measurements and quantum chemical simulations reveal that efficient SF occurs through the charge-transfer-assisted mechanism, entailing a large structural fluctuation. Our findings not only highlight the SF mechanism in PBI dimers but also suggest the factors responsible for an efficient SF process, which are important considerations in the design of molecular materials for photovoltaic devices.

10.
Cont Lens Anterior Eye ; 42(4): 420-427, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31029534

RESUMO

PURPOSE: To determine the repeatability of tear ferning (TF) grading analysed by subjective and objective techniques, and its correlation with lipid layer thickness (LLT), non-invasive keratograph break-up time (NIKBUT), and ocular surface disease index (OSDI) comfort scores with and without ocular lubricants. METHODS: A prospective, randomised, controlled clinical study was conducted. Eighteen healthy non-contact lens wearers aged between 18 to 45 years attended a total of three visits. They were randomly allocated to receive no drops on two occasions to examine method repeatability (visits A and B) or a 60 µL drop of Refresh® (visit C). At each visit, LLT and NIKBUT were assessed followed by basal tear collection. The TF pattern was established by pipetting one µL volume of tears onto a glass slide that was allowed to air-dry and imaged under a microscope. The resulting tear ferning pattern was determined using subjective grading and a novel computerized objective analysis technique that measured the local contrast of ferning contours. RESULTS: Paired t-tests found that all measurements collected between eyes, on different days for visit A and B were not significantly different (p >0.05). Eyes and days were averaged and compared to visit C. Paired t-tests between the averaged baseline visits and visit C for LLT, NIKBUT including subjective and objective TF scores showed no significant difference (p>0.05). No significant correlation was shown between the TF scoring and OSDI, LLT or NITBUT (p>0.05). There was however a high significant correlation and agreement between the subjective and objective analysis techniques for TF grading. CONCLUSIONS: TF grade, LLT and NITBUT are repeatable. As with other ocular surface assessments, subjective and objective TF gradings did not significantly correlate with the measures of tear film stability or comfort. Lubricants had no effect on TF grade, LLT or NITBUT. The novel objective analysis technique is a promising candidate for a repeatable and unbiased assessment of tear ferning.


Assuntos
Metabolismo dos Lipídeos/fisiologia , Lubrificantes Oftálmicos/administração & dosagem , Lágrimas/fisiologia , Administração Oftálmica , Adolescente , Adulto , Feminino , Voluntários Saudáveis , Humanos , Masculino , Microscopia , Variações Dependentes do Observador , Soluções Oftálmicas , Estudos Prospectivos , Reprodutibilidade dos Testes , Lágrimas/química , Acuidade Visual/fisiologia , Adulto Jovem
11.
Diabetes Metab J ; 43(4): 447-460, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30688047

RESUMO

BACKGROUND: Epidemiological studies have suggested an association between selenium (Se) and diabetes mellitus (DM). However, different studies have reported conflicting results. Therefore, we performed a comprehensive meta-analysis to clarify the impact of Se on DM. METHODS: We searched the PubMed database for studies on the association between Se and DM from inception to June 2018. RESULTS: Twenty articles evaluating 47,930 participants were included in the analysis. The meta-analysis found that high levels of Se were significantly associated with the presence of DM (pooled odds ratios [ORs], 1.88; 95% confidence interval [CI], 1.44 to 2.45). However, significant heterogeneity was found (I²=82%). Subgroup analyses were performed based on the Se measurement methods used in each study. A significant association was found between high Se levels and the presence of DM in the studies that used blood (OR, 2.17; 95% CI, 1.60 to 2.93; I²=77%), diet (OR, 1.61; 95% CI, 1.10 to 2.36; I²=0%), and urine (OR, 1.49; 95% CI, 1.02 to 2.17; I²=0%) as samples to estimate Se levels, but not in studies on nails (OR, 1.24; 95% CI, 0.52 to 2.98; I²=91%). Because of significant heterogeneity in the studies with blood, we conducted a sensitivity analysis and tested the publication bias. The results were consistent after adjustment based on the sensitivity analysis as well as the trim and fill analysis for publication bias. CONCLUSION: This meta-analysis demonstrates that high levels of Se are associated with the presence of DM. Further prospective and randomized controlled trials are warranted to elucidate the link better.


Assuntos
Diabetes Mellitus/sangue , Diabetes Mellitus/epidemiologia , Estudos Observacionais como Assunto , Selênio/sangue , Adulto , Idoso , Bases de Dados Factuais , Diabetes Mellitus/urina , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Unhas/química , Razão de Chances , Viés de Publicação , Selênio/urina
12.
Korean J Fam Med ; 40(2): 100-105, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30441887

RESUMO

BACKGROUND: Osteoporosis and osteopenia are characterized by reduced bone mineral density (BMD) and increased fracture risk. Although the risk of fractures is higher in underweight people than in overweight people, the accumulation of body fat (especially abdominal fat) can increase the risk of bone loss. This study aimed to evaluate the association between body fat percentage and BMD in normal-weight middle-aged Koreans. METHODS: This study included 1,992 adults (mean age, 48.7 years; 52.9% women). BMD and body fat were measured using dual-energy X-ray absorptiometry. Multiple linear regression analyses and analysis of covariance were used to assess the association between BMD and body fat. Body fat percentage was grouped by cut-off values. The cut-off values were 20.6% and 25.7% for men with a body mass index of 18.5-22.9 kg/m2 , while the cut-off values were 33.4% and 36% for women. RESULTS: Body fat percentage tended to be negatively associated with BMD. Increased body fat percentage was associated with reduced BMD in normal-weight middle-aged adults. The effects of body fat percentage on BMD in normal-weight individuals were more pronounced in men than in women. CONCLUSION: There was a negative correlation between BMD and body fat percentage in middle-aged Korean men and women with normal body weight. This association was stronger in men than in women.

13.
Vision Res ; 146-147: 32-40, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29499211

RESUMO

Reducing the amount of motion information can surprisingly make motion look faster (e.g., motion behind Venetian blinds). We found that a textured pattern moving to the right at speeds ranging from 0.34 to 5.5°/s appeared to move 50% faster when viewed through a short (0.5°) compared with a long (4.5°) horizontal slot. Perceived speed varied inversely with the log of the slot length. We varied the length of rectangular apertures over a tenfold range and manipulated their size, shape, and orientation. We attribute the field-size effect mostly to landmarks provided by the ends of the slots, but we also examined temporal and spatial frequency and lateral inhibition of motion.


Assuntos
Percepção de Movimento/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Campos Visuais/fisiologia , Humanos , Ilusões Ópticas , Orientação Espacial , Tempo de Reação
14.
Clin Exp Optom ; 101(2): 147-161, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29193361

RESUMO

Interest has grown over the past decade in using in vivo confocal microscopy to analyse the morphology of corneal nerves and their changes over time. Advances in computational modelling techniques have been applied to automate the estimation of sub-basal nerve structure. These objective methods have the potential to quantify nerve density (and length), tortuosity, variations in nerve thickness, as well as temporal changes in nerve fibres such as migration patterns. Different approaches to automated nerve analysis, methods proposed and how they were validated in previous literature are reviewed. Improved understanding of these approaches and their limitations will help improve the diagnostic leverage of emerging developments for monitoring the onset and progression of a broad class of systemic diseases, including diabetes.


Assuntos
Córnea/inervação , Microscopia Confocal/métodos , Nervo Oftálmico/diagnóstico por imagem , Humanos , Fibras Nervosas
15.
Proc Natl Acad Sci U S A ; 114(52): 13840-13845, 2017 12 26.
Artigo em Inglês | MEDLINE | ID: mdl-29229812

RESUMO

A fundamental problem in extracting scene structure is distinguishing different physical sources of image structure. Light reflected by an opaque surface covaries with local surface orientation, whereas light transported through the body of a translucent material does not. This suggests the possibility that the visual system may use the covariation of local surface orientation and intensity as a cue to the opacity of surfaces. We tested this hypothesis by manipulating the contrast of luminance gradients and the surface geometries to which they belonged and assessed how these manipulations affected the perception of surface opacity/translucency. We show that (i) identical luminance gradients can appear either translucent or opaque depending on the relationship between luminance and perceived 3D surface orientation, (ii) illusory percepts of translucency can be induced by embedding opaque surfaces in diffuse light fields that eliminate the covariation between surface orientation and intensity, and (iii) illusory percepts of opacity can be generated when transparent materials are embedded in a light field that generates images where surface orientation and intensity covary. Our results provide insight into how the visual system distinguishes opaque surfaces and light-permeable materials and why discrepancies arise between the perception and physics of opacity and translucency. These results suggest that the most significant information used to compute the perceived opacity and translucency of surfaces arise at a level of representation where 3D shape is made explicit.


Assuntos
Sensibilidades de Contraste/fisiologia , Mascaramento Perceptivo/fisiologia , Feminino , Humanos , Masculino
16.
Optom Vis Sci ; 94(7): 726-731, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28650386

RESUMO

PURPOSE: This work aims to characterize the relationship between tear film neuropeptide substance P and the structural integrity of the sub-basal nerve plexus in diabetes. METHODS: Seventeen healthy control participants and nine participants with diabetes were recruited in this cross-sectional study. Total protein content and substance P concentrations were determined in the flush tears of participants. Corneal nerve morphology was assessed by capturing the corneal sub-basal nerve plexus using the Heidelberg Retinal Tomograph II with the Rostock Corneal Module (Heidelberg Engineering GmbH, Heidelberg, Germany) in the central cornea. Corneal nerve fiber density (CNFD) was measured using ACCMetrics (M.A. Dabbah, Imaging Science and Biomedical Engineering, Manchester, UK) on eight captured images. Comparisons between groups were made using independent samples t-tests. Correlations between parameters were analyzed using Pearson's correlations. RESULTS: Substance P concentrations were significantly higher in the tears of the control group compared to participants with diabetes (4150 ± 4752 and 1473 ± 1671 pg/mL, respectively, P = .047). There was no significant difference in total protein content between the groups (3.4 ± 1.8 and 2.6 ± 1.7 mg/mL in the control and diabetes groups, respectively, P = .262). CNFD was significantly lower in the participants with diabetes compared to the control group (16.1 ± 5.7 and 21.5 ± 7.0 mm/mm, respectively, P = .041). There was a moderate correlation between substance P and CNFD (r = 0.48, P = .01). CONCLUSIONS: Substance P is expressed at a significantly lower level in the tears of people with diabetes compared with healthy controls. The positive correlation between substance P and corneal nerve density indicates that substance P may be a potential biomarker for corneal nerve health.


Assuntos
Córnea/inervação , Doenças da Córnea/patologia , Diabetes Mellitus Tipo 2/metabolismo , Proteínas do Olho/metabolismo , Substância P/metabolismo , Lágrimas/metabolismo , Doenças do Nervo Trigêmeo/patologia , Estudos de Casos e Controles , Doenças da Córnea/metabolismo , Estudos Transversais , Diabetes Mellitus Tipo 2/patologia , Feminino , Humanos , Masculino , Microscopia Confocal , Pessoa de Meia-Idade , Fibras Nervosas/patologia , Estudos Prospectivos , Nervo Trigêmeo/patologia , Doenças do Nervo Trigêmeo/metabolismo
17.
J Vis ; 17(3): 17, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28355629

RESUMO

Previous studies have shown that the perceived three-dimensional (3D) shape of objects depends on their material composition. The majority of this work has focused on glossy, flat-matte, or velvety materials. Here, we studied perceived 3D shape of translucent materials. We manipulated the spatial frequency of surface relief perturbations of translucent and opaque objects. Observers indicated which of two surfaces appeared to have more bumps. They also judged local surface orientation using gauge probe figures. We found that translucent surfaces appeared to have fewer bumps than opaque surfaces with the same 3D shape (Experiment 1), particularly when self-occluding contours were hidden from view (Experiment 2). We also found that perceived local curvature was underestimated for translucent objects relative to opaque objects, and that estimates of perceived local surface orientation were similarly correlated with luminance for images of both opaque and translucent objects (Experiment 3). These findings suggest that the perceived mesoscopic shape of completely matte translucent objects can be underestimated due to a decline in the steepness of luminance gradients relative to those of opaque objects.


Assuntos
Percepção de Forma/fisiologia , Imageamento Tridimensional , Propriedades de Superfície , Adulto , Meios de Contraste , Percepção de Profundidade/fisiologia , Humanos , Orientação Espacial
18.
Clin Exp Optom ; 100(3): 214-226, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-27728957

RESUMO

BACKGROUND: Accurate diagnosis in patients presenting with lesions at various locations within the visual pathway is challenging. This study investigated functional and structural changes secondary to such lesions to identify patterns useful to guide early and effective management. METHODS: Over 10,000 records from patients referred for optic nerve head assessment were reviewed and 31 patients with a final diagnosis of likely neuropathic lesions posterior to the eye were included in the current study. Fundus photographs, optic coherence tomography images and visual field tests were evaluated for changes with respect to retinal nerve fibre layer topography and prediction of structure-function paradigms. Emerging clinical patterns were examined for their consistency with the likely anatomical origin of the underlying insult in the presence of varying diagnoses. RESULTS: Data from patients with lesions along the visual system allowed identification of retinal nerve fibre layer asymmetry correlated with visual field defects and ganglion cell analysis. Bilateral discordance in retinal nerve fibre loss easily discernible from an altered pattern of the temporal-superior-nasal-inferior-temporal curve was characteristic for post-chiasmal lesions. These sometimes-subtle changes supported diagnosis in cases with multiple aetiologies or with ambiguous visual field analysis and/or ganglion cell loss. CONCLUSION: Intricate knowledge of the retinal architecture and projections allows coherent predictions of functional and structural deficits following various lesions affecting the visual pathway. The integration of adjunct imaging and retinal nerve fibre layer thinning will assist clinicians to guide clinical investigations toward a likely diagnosis in the light of significant individual variations. The case series presented in this study aids in differential diagnosis of retrograde optic neuropathies by using retinal nerve fibre layer asymmetric patterns as an important clinical marker.


Assuntos
Fibras Nervosas/patologia , Disco Óptico/patologia , Doenças do Nervo Óptico/diagnóstico , Células Ganglionares da Retina/patologia , Escotoma/diagnóstico , Tomografia de Coerência Óptica/métodos , Campos Visuais/fisiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Doenças do Nervo Óptico/complicações , Doenças do Nervo Óptico/fisiopatologia , Estudos Retrospectivos , Escotoma/etiologia , Escotoma/fisiopatologia , Adulto Jovem
19.
J Vis ; 16(14): 7, 2016 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-27832269

RESUMO

Although observer motions project different patterns of optic flow to our left and right eyes, there has been surprisingly little research into potential stereoscopic contributions to self-motion perception. This study investigated whether visually induced illusory self-motion (i.e., vection) is influenced by the addition of consistent stereoscopic information to radial, circular, and spiral (i.e., combined radial + circular) patterns of optic flow. Stereoscopic vection advantages were found for radial and spiral (but not circular) flows when monocular motion signals were strong. Under these conditions, stereoscopic benefits were greater for spiral flow than for radial flow. These effects can be explained by differences in the motion aftereffects generated by these displays, which suggest that the circular motion component in spiral flow selectively reduced adaptation to stereoscopic motion-in-depth. Stereoscopic vection advantages were not observed for circular flow when monocular motion signals were strong, but emerged when monocular motion signals were weakened. These findings show that stereoscopic information can contribute to visual self-motion perception in multiple ways.


Assuntos
Percepção de Profundidade/fisiologia , Percepção de Movimento/fisiologia , Fluxo Óptico/fisiologia , Ilusões Ópticas/fisiologia , Visão Binocular/fisiologia , Adulto , Feminino , Humanos , Masculino , Adulto Jovem
20.
Iperception ; 7(4): 2041669516658047, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27698976

RESUMO

We experience vivid percepts of objects and materials despite complexities in the way images are structured by the interaction of light with surface properties (3D shape, albedo, and gloss or specularity). Although the perception of gloss (and lightness) has been argued to depend on image statistics (e.g., sub-band skew), studies have shown that perceived gloss depends critically on the structure of luminance variations in images. Here, we found that separately adapting observers to either positive or negative skew generated declines in perceived gloss, contrary to the predictions of theories involving image statistics. We also found similar declines in perceived gloss following adaptation to contours geometrically correlated with sharp specular edges. We further found this aftereffect was stronger when contour adaptors were aligned with specular edges compared with adaptation to the same contours rotated by 90°. These findings support the view that the perception of gloss depends critically on the visual system's ability to encode specular edge structure and not image skew.

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