92 research outputs found
Object knowledge modulates colour appearance
We investigated the memory colour effect for colour diagnostic artificial objects. Since knowledge about these objects and their colours has been learned in everyday life, these stimuli allow the investigation of the influence of acquired object knowledge on colour appearance. These investigations are relevant for questions about how object and colour information in high-level vision interact as well as for research about the influence of learning and experience on perception in general. In order to identify suitable artificial objects, we developed a reaction time paradigm that measures (subjective) colour diagnosticity. In the main experiment, participants adjusted sixteen such objects to their typical colour as well as to grey. If the achromatic object appears in its typical colour, then participants should adjust it to the opponent colour in order to subjectively perceive it as grey. We found that knowledge about the typical colour influences the colour appearance of artificial objects. This effect was particularly strong along the daylight axis
The effect of adherence to spectacle wear on early developing literacy: a longitudinal study based in a large multi-ethnic city, Bradford, UK
YesObjectives: To determine the impact of adherence to
spectacle wear on visual acuity (VA) and developing
literacy following vision screening at age 4â5 years.
Design: Longitudinal study nested within the Born in
Bradford birth cohort.
Setting and participants: Observation of 944 children:
432 had failed vision screening and were referred
(treatment group) and 512 randomly selected (comparison
group) who had passed (<0.20 logarithm of the minimum
angle of resolution (logMAR) in both eyes). Spectacle wear
was observed in school for 2 years following screening
and classified as adherent (wearing spectacles at each
assessment) or non-adherent.
Main outcome measures: Annual measures of VA
using a crowded logMAR test. Literacy was measured by
Woodcock Reading Mastery Tests-Revised subtest: letter
identification.
Results: The VA of all children improved with increasing
age, â0.009 log units per month (95% CI â0.011 to
â0.007) (worse eye). The VA of the adherent group
improved significantly more than the comparison group, by
an additional â0.008 log units per month (95% CI â0.009
to â0.007) (worse eye) and â0.004 log units per month
(95% CI â0.005 to â0.003) in the better eye. Literacy was
associated with the VA, letter identification (ID) reduced
by â0.9 (95% CI â1.15 to â0.64) for every one line (0.10
logMAR) fall in VA (better eye). This association remained
after adjustment for socioeconomic and demographic
factors (â0.33, 95% CI â0.54 to â0.12). The adherent
group consistently demonstrated higher letter-ID scores
compared with the non-adherent group, with the greatest
effect size (0.11) in year 3.
Conclusions: Early literacy is associated with the level of
VA; children who adhere to spectacle wear improve their
VA and also have the potential to improve literacy. Our
results suggest failure to adhere to spectacle wear has
implications for the childâs vision and education.AB is funded by a National Institute for Health Research Post- Doctoral Fellowship Award (PDF-2013-06-050). The Born in Bradford study presents independent research commissioned by the National Institute for Health Research Collaboration for Applied Health Research and Care (NIHR CLAHRC) and the Programme Grants for Applied Research funding scheme (RP-PG-0407-10044)
Waking up dormant tumor suppressor genes with zinc fingers, TALEs and the CRISPR/dCas9 system
The aberrant epigenetic silencing of tumor suppressor genes (TSGs) plays a major role during carcinogenesis and regaining these dormant functions by engineering of sequence-specific epigenome editing tools offers a unique opportunity for targeted therapies. However, effectively normalizing the expression and regaining tumor suppressive functions of silenced TSGs by artificial transcription factors (ATFs) still remains a major challenge. Herein we describe novel combinatorial strategies for the potent reactivation of two class II TSGs, MASPIN and REPRIMO, in cell lines with varying epigenetic states, using the CRISPR/dCas9 associated system linked to a panel of effector domains (VP64, p300, VPR and SAM complex), as well as with protein-based ATFs, Zinc Fingers and TALEs. We found that co-delivery of multiple effector domains using a combination of CRISPR/dCas9 and TALEs or SAM complex maximized activation in highly methylated promoters. In particular, CRISPR/dCas9 VPR with SAM upregulated MASPIN mRNA (22,145-fold change) in H157 lung cancer cells, with accompanying re-expression of MASPIN protein, which led to a concomitant inhibition of cell proliferation and induction of apoptotic cell death. Consistently, CRISPR/dCas9 VP64 with SAM upregulated REPRIMO (680-fold change), which led to phenotypic reprogramming in AGS gastric cancer cells. Altogether, our results outlined novel sequence-specific, combinatorial epigenome editing approaches to reactivate highly methylated TSGs as a promising therapy for cancer and other diseases
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Asymmetries between achromatic and chromatic extraction of 3D motion signals
Motion in depth (MID) can be cued by high-resolution changes in binocular disparity over time (CD), and low-resolution interocular velocity differences (IOVD). Computational differences between these two mechanisms suggest that they may be implemented in visual pathways with different spatial and temporal resolutions. Here, we used fMRI to examine how achromatic and S-cone signals contribute to human MID perception. Both CD and IOVD stimuli evoked responses in a widespread network that included early visual areas, parts of the dorsal and ventral streams, and motion-selective area hMT+. Crucially, however, we measured an interaction between MID type and chromaticity. fMRI CD responses were largely driven by achromatic stimuli, but IOVD responses were better driven by isoluminant S-cone inputs. In our psychophysical experiments, when S-cone and achromatic stimuli were matched for perceived contrast, participants were equally sensitive to the MID in achromatic and S-cone IOVD stimuli. In comparison, they were relatively insensitive to S-cone CD. These findings provide evidence that MID mechanisms asymmetrically draw on information in precortical pathways. An early opponent motion signal optimally conveyed by the S-cone pathway may provide a substantial contribution to the IOVD mechanism
Sun and sky: Does human vision assume a mixture of point and diffuse illumination when interpreting shape-from-shading?
AbstractPeople readily perceive smooth luminance variations as being due to the shading produced by undulations of a 3-D surface (shape-from-shading). In doing so, the visual system must simultaneously estimate the shape of the surface and the nature of the illumination. Remarkably, shape-from-shading operates even when both these properties are unknown and neither can be estimated directly from the image. In such circumstances humans are thought to adopt a default illumination model. A widely held view is that the default illuminant is a point source located above the observerâs head. However, some have argued instead that the default illuminant is a diffuse source. We now present evidence that humans may adopt a flexible illumination model that includes both diffuse and point source elements. Our model estimates a direction for the point source and then weights the contribution of this source according to a bias function. For most people the preferred illuminant direction is overhead with a strong diffuse component
Two nonspecific phospholipid exchange proteins from beef liver. 1. Purification and characterization
Participation as a mechanism to favour psychological empowerment and positive interaction: The âĂgora Infantilâ participatory democracy programme
This investigation aims to show the relationship between
participation and psychological empowerment and between
participation and interaction under an institutional
political participation programme. This initiative known as
Ăgora Infantil (AI) is characterised by an obligatory drawâ
based deliberative participation methodology with superordinate
goals based on group dynamics, with games
playing a central role. The evaluation was carried out using
a quasiâexperimental design, with quantitative measurements
of the experimental and control groups, along with
systematic observation of the target group. The results
support the hypotheses proposed: Participation in the AI
programme led to an increase in psychological empowerment
and positive interactions between the participants.
These results offer information as to what design should
be used for these types of political initiatives to favour
inclusion and empowerment of children, while at the same
time improving classroom relationships
Cultural Agenda Setting: Media Attributes and Public Attention of Greek Museums
The recent transformation of cultural organizations has altered their relationship with the public, evidenced by their engaging in market research and analysis of public perceptions about their identity, mission, and services. Through the lens of agenda-setting theory, this paper examines whether, alongside other factors, media coverage of museums can drive museum visitation. We pursue a second level of agenda-setting analysis, examining the relationship between valence-the positive, negative and neutral portrayals of museums in the media-and visitation. We conduct an econometric analysis of monthly data for the period June 2004-June 2008 for a sample of major Greek museums. The study reveals that media coverage of cultural organizations and positive valence constitute significant elements of reputation, which subsequently drive museum visitation
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