603 resultados para disparities
Resumo:
Women are under-represented at senior levels within organisations. They also fareless well than their male counterparts in reward and career opportunities. Attitudestoward women in the workplace are thought to underpin these disparities and moreand more organisations are introducing attitude measures into diversity and inclusioninitiatives to: 1) raise awareness amongst employees of implicit attitudes, 2) educateemployees on how these attitudes can influence behaviour and 3) re-measure theattitude after an intervention to assess whether the attitude has changed. TheImplicit Association Test (IAT: Greenwald, et al., 1998) is the most popular tool usedto assess attitudes. However, questions over the predictive validity of the measurehave been raised and the evidence for the real world impact of the implicit attitudes islimited (Blanton et al., 2009; Landy, 2008; Tetlock & Mitchell, 2009; Wax, 2010).Whilst there is growing research in the area of race, little research has explored theability of the IAT to predict gender discrimination. This thesis addresses thisimportant gap in the literature. Three empirical studies were conducted. The firststudy explored whether gender IATs were predictive of personnel decisions thatfavour men and whether affect- and cognition-based gender IATs were equallypredictive of behaviour. The second two studies explored the predictive validity ofthe IAT in comparison to an explicit measure of one type of gender attitude,benevolent sexism. The results revealed implicit gender attitudes were stronglyheld. However, they did not consistently predict behaviour across the studies.Overall, the results suggest that the IAT may only predict workplace genderdiscrimination in a very select set of circumstances. The attitude component that anIAT assesses, the personnel decision and participant demographics all impact thepredictive validity of the tool. The interplay between the IAT and behaviour thereforeappears to be more complex than is assumed.
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With luminance gratings, psychophysical thresholds for detecting a small increase in the contrast of a weak ‘pedestal’ grating are 2–3 times lower than for detection of a grating when the pedestal is absent. This is the ‘dipper effect’ – a reliable improvement whose interpretation remains controversial. Analogies between luminance and depth (disparity) processing have attracted interest in the existence of a ‘disparity dipper’. Are thresholds for disparity modulation (corrugated surfaces), facilitated by the presence of a weak disparity-modulated pedestal? We used a 14-bit greyscale to render small disparities accurately, and measured 2AFC discrimination thresholds for disparity modulation (0.3 or 0.6 c/deg) of a random texture at various pedestal levels. In the first experiment, a clear dipper was found. Thresholds were about 2× lower with weak pedestals than without. But here the phase of modulation (0 or 180 deg) was varied from trial to trial. In a noisy signal-detection framework, this creates uncertainty that is reduced by the pedestal, which thus improves performance. When the uncertainty was eliminated by keeping phase constant within sessions, the dipper effect was weak or absent. Monte Carlo simulations showed that the influence of uncertainty could account well for the results of both experiments. A corollary is that the visual depth response to small disparities is probably linear, with no threshold-like nonlinearity.
Resumo:
Measurement of detection and discrimination thresholds yields information about visual signal processing. For luminance contrast, we are 2 - 3 times more sensitive to a small increase in the contrast of a weak 'pedestal' grating, than when the pedestal is absent. This is the 'dipper effect' - a reliable improvement whose interpretation remains controversial. Analogies between luminance and depth (disparity) processing have attracted interest in the existence of a 'disparity dipper' - are thresholds for disparity, or disparity modulation (corrugated surfaces), facilitated by the presence of a weak pedestal? Lunn and Morgan (1997 Journal of the Optical Society of America A 14 360 - 371) found no dipper for disparity-modulated gratings, but technical limitations (8-bit greyscale) might have prevented the necessary measurement of very small disparity thresholds. We used a true 14-bit greyscale to render small disparities accurately, and measured 2AFC discrimination thresholds for disparity modulation (0.6 cycle deg-1) of a random texture at various pedestal levels. Which interval contained greater modulation of depth? In the first experiment, a clear dipper was found. Thresholds were about 2X1 lower with weak pedestals than without. But here the phase of modulation (0° or 180°) was randomised from trial to trial. In a noisy signal-detection framework, this creates uncertainty that is reduced by the pedestal, thus improving performance. When the uncertainty was eliminated by keeping phase constant within sessions, the dipper effect disappeared, confirming Lunn and Morgan's result. The absence of a dipper, coupled with shallow psychometric slopes, suggests that the visual response to small disparities is essentially linear, with no threshold-like nonlinearity.
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This thesis begins by providing a review of techniques for interpreting the thermal response at the earth's surface acquired using remote sensing technology. Historic limitations in the precision with which imagery acquired from airborne platforms can be geometrically corrected and co-registered has meant that relatively little work has been carried out examining the diurnal variation of surface temperature over wide regions. Although emerging remote sensing systems provide the potential to register temporal image data within satisfactory levels of accuracy, this technology is still not widely available and does not address the issue of historic data sets which cannot be rectified using conventional parametric approaches. In overcoming these problems, the second part of this thesis describes the development of an alternative approach for rectifying airborne line-scanned imagery. The underlying assumption that scan lines within the imagery are straight greatly reduces the number of ground control points required to describe the image geometry. Furthermore, the use of pattern matching procedures to identify geometric disparities between raw line-scanned imagery and corresponding aerial photography enables the correction procedure to be almost fully automated. By reconstructing the raw image data on a truly line-by-line basis, it is possible to register the airborne line-scanned imagery to the aerial photography with an average accuracy of better than one pixel. Providing corresponding aerial photography is available, this approach can be applied in the absence of platform altitude information allowing multi-temporal data sets to be corrected and registered.
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Presentaton Purpose:We conducted a small study to assess the novel, retro - mode imaging technique of the NIDEK F-10 scanning laser ophthalmoscope, for detecting and quantifying retinal drusen. Methods:Fundus photographs of 4 eyes of 2 patients taken in retro-mode on the Nidek F-10 SLO were graded independently by 6,experienced, masked fundus graders for the presence of retinal drusen , and compared to stereo colour fundus photographs taken with a Topcon TRC-50DX camera. Results:The mean number of retinal drusen detected in retro mode was 142.96+/- 60.8, range 63-265, and on colour fundus photography mean of 66.6+/-32.6, range 26-177. All observers independently detected approximately twice as many drusen on retro-mode than colour fundus photography (p<0.0001, Student’s paired t-test) . The statistical significance of interobserver variation in drusen detection was p=0.07 on colour fundus photography , and p=0.02 on retro mode ( ANOVA) . Conclusions:The retro-mode of the F-10 camera uses infrared laser and an aperture with a modified central stop, with the aperture deviated laterally from the confocal light path. This forms a pseudo -3D image which is a new means of detecting abnomalites in the deeper retinal layers. Retro-mode imaging of retinal drusen using the F-10 Nidek SLO is a highly sensitive technique for detecting and quantifying retinal drusen , and detected twice as many drusen than colour fundus photography. This small pilot study suggests that this novel type of imaging may have a role in the future detection and analysis of retinal drusen, a field that is likely to become increasingly important in future AMD prevention studies.
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Presentation Purpose:To examine the correlation of central visual field loss and progression of structural changes in the macular area in age-related macular degeneration (AMD). Methods:Central 10° standard and short-wavelength automated perimetry (SWAP) visual fields were acquired in 39 eyes of 24 patients with AMD using a Humphrey Field Analyzer. Stereoscopic fundus photographs were graded1 by two independent observers and the stage of disease determined2. Custom software mapped perimetric data onto fundus images in order to relate structural changes to functional loss. Results:Mean deviation (MD) in standard perimetry changed from 0.04 dB at stage 1 to -12.39 dB at stage 4 (r2=0.48, p<0.001). The group mean SWAP MD was -5.26 dB at stage 1 and increased to -17.08 dB at stage 4 (r2=0.53, p<0.001). Pattern standard deviation (PSD) also increased with advancing stage in standard perimetry; 1.32 dB to 8.67 dB at stage 1 and 4, respectively (r2=0.54, p<0.001). In SWAP, PSD increased from 2.86 dB to 5.63 dB at stage 1 and stage 4 (r2=0.43, p<0.001). Defect frequency was greater in SWAP than standard perimetry. Early stage defects occurred with the greatest frequency at eccentricities of 3.2° and 5.1° in standard perimetry and at 4.2° in SWAP. Late stage defects were most frequent at 1° eccentricity in standard perimetry and at 1° and 9° in SWAP. MD declined with increasing affected retinal area over the central 3000µm; by 0.20 dB (r2=0.67, p<0.001) and 0.18 dB (r2=0.49, p<0.001) per % increase in defect area for standard perimetry and SWAP respectively. 41% of defects were associated with structural changes on the retina in standard perimetry and 43% in SWAP. Conclusions:Sensitivity decreased with advancing stage of AMD, with a greater effect demonstrated in SWAP compared to standard perimetry. The central field became less uniform as stage increased. SWAP defects occurred at similar locations but were deeper and wider than corresponding defects in standard perimetry. Central loss in SWAP is a sensitive marker of functional progression in AMD.1. Bird et al. (1995) Surv Ophthalmol 39:367-3742. van Leeuwen et al. (2003) Arch Ophthalmol 121:519-526
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Presentation Purpose:We conducted a study to determine if the spectral domain optical coherence tomography (SD-OCT) could be used as a tool to assess effective delivery of threshold and subthreshold laser burns created using 532nm green wavelength laser. Methods:10 patients planned for panretinal photocoagulation (PRP) for proliferative diabetic retinopathy were included in this study. Before initiating the full PRP, a row of moderately white laser burns as used for conventional PRP was created using 532 nm laser set at threshold power for 0.1 second with 300 microns spot size. Further rows of laser burns were created by altering the duration and power settings on the laser device. The area of the retina irradiated with laser was imaged using the Topcon SD-OCT within a few minutes of laser treatment. Results:Laser burns created using threshold power were seen on the OCT scan in all cases as a homogenous diffuse increase in reflectivity extending across the full thickness of retina (Fig 1). Retinal burns created by lowering the duration of laser pulse to 0.01s were barely visible ophthalmoscopically but were clearly detectable on the OCT scan as a localised, well-defined area of increased tissue reflectivity (Fig 2). Conclusions:OCT is a useful to tool to assess the delivery of laser burns created using the 532 nm green laser. Burns of a subthreshold intensity that may not be visible ophthalmoscopically result in retinal changes that are clearly detectable on OCT imaging. Further studies would be needed to assess the clinical effectiveness of subthreshold laser treatment for retinal vascular diseases using the 532 nm green laser.
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Albumin is not endogenous to the tear film and is present as a product of plasma leakage. It is used as a diagnostic marker of ocular insult and inflammation. Tear albumin is, however, poorly understood, with large variations in reported concentrations between studies. There is also no authoritative information on whether its presence in tears is responsive or part of an adaptive reaction.The presented research aimed to resolve the disparities in published tear albumin concentrations and investigate the role of albumin in the tear film. Collation and evaluation of the available literature identified collection method, stimulus, assay technique, and disease state as factors able to influence quoted tear albumin to different extents. Difference in sampling technique exhibited the largest variations in mean tear albumin concentrations. Review of the literature also highlighted that little systematic investigations of the daily cycle of tear albumin levels, and subject-to-subject-variation, had been carried out. In order to remedy this shortcoming, variations in tear albumin concentration were investigated in 13 subjects throughout the waking day. Results identified a time period where albumin levels are relatively stable (2-6 hours post-waking). This was designated a suitable baseline for the determinations of tear albumin concentrations and subject-to-subject comparisons. Significantly, a previously unrecognised progressive increase in albumin concentration during the latter part of the day was also identified in the population. This increase suggests that albumin may play a more active and dynamic role in the ocular environment than is commonly perceived. To facilitate the collection of additional tear albumin data, tear sampling and point-of-care analysis in contact lens clinics were investigated. Two instruments were evaluated and were found to be suitable for the analysis of tear albumin in commercial institutions. Collectively, the described research has provided new insight into tear albumin and a strong foundation for further studies.
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In this paper we provide evidence for the effects of social norms on audit pricing by studying companies belonging to the alcohol, firearms, gambling, military, nuclear power, and tobacco industries,which are often described as “sin” companies. We hypothesize that the disparities between “sin” firms operations and prevailing social norms create an adverse context which heightens the client's business risk assessment by auditors and is, thereby, reflected in the pricing decisions for audit and consulting services. Having controlled for the impact of variables relating to client attributes, auditor attributes and engagement attributes, we demonstrate that audit firms charge significantly higher audit and consulting fees to companies that deviate from prevailing social norms. Additionally,we show that audit pricing levels within the “sin” group depend both on prevailing political views and on the level of “vice” exhibited by “sin” companies.
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Purpose: (1) To devise a model-based method for estimating the probabilities of binocular fusion, interocular suppression and diplopia from psychophysical judgements, (2) To map out the way fusion, suppression and diplopia vary with binocular disparity and blur of single edges shown to each eye, (3) To compare the binocular interactions found for edges of the same vs opposite contrast polarity. Methods: Test images were single, horizontal, Gaussian-blurred edges, with blur B = 1-32 min arc, and vertical disparity 0-8.B, shown for 200 ms. In the main experiment, observers reported whether they saw one central edge, one offset edge, or two edges. We argue that the relation between these three response categories and the three perceptual states (fusion, suppression, diplopia) is indirect and likely to be distorted by positional noise and criterion effects, and so we developed a descriptive, probabilistic model to estimate both the perceptual states and the noise/criterion parameters from the data. Results: (1) Using simulated data, we validated the model-based method by showing that it recovered fairly accurately the disparity ranges for fusion and suppression, (2) The disparity range for fusion (Panum's limit) increased greatly with blur, in line with previous studies. The disparity range for suppression was similar to the fusion limit at large blurs, but two or three times the fusion limit at small blurs. This meant that diplopia was much more prevalent at larger blurs, (3) Diplopia was much more frequent when the two edges had opposite contrast polarity. A formal comparison of models indicated that fusion occurs for same, but not opposite, polarities. Probability of suppression was greater for unequal contrasts, and it was always the lower-contrast edge that was suppressed. Conclusions: Our model-based data analysis offers a useful tool for probing binocular fusion and suppression psychophysically. The disparity range for fusion increased with edge blur but fell short of complete scale-invariance. The disparity range for suppression also increased with blur but was not close to scale-invariance. Single vision occurs through fusion, but also beyond the fusion range, through suppression. Thus suppression can serve as a mechanism for extending single vision to larger disparities, but mainly for sharper edges where the fusion range is small (5-10 min arc). For large blurs the fusion range is so much larger that no such extension may be needed. © 2014 The College of Optometrists.
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Saturation mutagenesis is a powerful tool in modern protein engineering. This can allow the analysis of potential new properties thus allowing key residues within a protein to be targeted and randomised. However, the creation of large libraries using conventional saturation mutagenesis with degenerate codons (NNN or NNK) has inherent redundancy and disparities in residue representation. In this we describe the combination of ProxiMAX randomisation and CIS display for the use of generating novel peptides. Unlike other methods ProxiMAX randomisation does not require any intricate chemistry but simply utilises synthetic DNA and molecular biology techniques. Designed ‘MAX’ oligonucleotides were ligated, amplified and digested in an iterative cycle. Results show that randomised ‘MAX’ codons can be added sequentially to the base sequence creating a series of randomised non-degenerate codons that can subsequently be inserted into a gene. CIS display (Isogencia, UK) is an in vitro DNA based screening method that creates a genotype to phenotype link between a peptide and the nucleic acid that encodes it. The use of straight forward in vitro transcription/translation and other molecular biology techniques permits ease of use along with flexibility making it a potent screening technique. Using ProxiMAX randomisation in combination with CIS display, the aim is to produce randomised anti-nerve growth factor (NGF) and calcitonin gene-related (CGRP) peptides to demonstrate the high-throughput nature of this combination.
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This paper explores differences in how primary care doctors process the clinical presentation of depression by African American and African-Caribbean patients compared with white patients in the US and the UK. The aim is to gain a better understanding of possible pathways by which racial disparities arise in depression care. One hundred and eight doctors described their thought processes after viewing video recorded simulated patients presenting with identical symptoms strongly suggestive of depression. These descriptions were analysed using the CliniClass system, which captures information about micro-components of clinical decision making and permits a systematic, structured and detailed analysis of how doctors arrive at diagnostic, intervention and management decisions. Video recordings of actors portraying black (both African American and African-Caribbean) and white (both White American and White British) male and female patients (aged 55 years and 75 years) were presented to doctors randomly selected from the Massachusetts Medical Society list and from Surrey/South West London and West Midlands National Health Service lists, stratified by country (US v.UK), gender, and years of clinical experience (less v. very experienced). Findings demonstrated little evidence of bias affecting doctors' decision making processes, with the exception of less attention being paid to the potential outcomes associated with different treatment options for African American compared with White American patients in the US. Instead, findings suggest greater clinical uncertainty in diagnosing depression amongst black compared with white patients, particularly in the UK. This was evident in more potential diagnoses. There was also a tendency for doctors in both countries to focus more on black patients' physical rather than psychological symptoms and to identify endocrine problems, most often diabetes, as a presenting complaint for them. This suggests that doctors in both countries have a less well developed mental model of depression for black compared with white patients. © 2014 The Authors.
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Neuroimaging (NI) technologies are having increasing impact in the study of complex cognitive and social processes. In this emerging field of social cognitive neuroscience, a central goal should be to increase the understanding of the interaction between the neurobiology of the individual and the environment in which humans develop and function. The study of sex/gender is often a focus for NI research, and may be motivated by a desire to better understand general developmental principles, mental health problems that show female-male disparities, and gendered differences in society. In order to ensure the maximum possible contribution of NI research to these goals, we draw attention to four key principles—overlap, mosaicism, contingency and entanglement—that have emerged from sex/gender research and that should inform NI research design, analysis and interpretation. We discuss the implications of these principles in the form of constructive guidelines and suggestions for researchers, editors, reviewers and science communicators.
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Binocular combination for first-order (luminancedefined) stimuli has been widely studied, but we know rather little about this binocular process for spatial modulations of contrast (second-order stimuli). We used phase-matching and amplitude-matching tasks to assess binocular combination of second-order phase and modulation depth simultaneously. With fixed modulation in one eye, we found that binocularly perceived phase was shifted, and perceived amplitude increased almost linearly as modulation depth in the other eye increased. At larger disparities, the phase shift was larger and the amplitude change was smaller. The degree of interocular correlation of the carriers had no influence. These results can be explained by an initial extraction of the contrast envelopes before binocular combination (consistent with the lack of dependence on carrier correlation) followed by a weighted linear summation of second-order modulations in which the weights (gains) for each eye are driven by the first-order carrier contrasts as previously found for first-order binocular combination. Perceived modulation depth fell markedly with increasing phase disparity unlike previous findings that perceived first-order contrast was almost independent of phase disparity. We present a simple revision to a widely used interocular gain-control theory that unifies first- and second-order binocular summation with a single principle-contrast-weighted summation-and we further elaborate the model for first-order combination. Conclusion: Second-order combination is controlled by first-order contrast.
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Objective: To determine the impact of doctors' communication style and doctor-patient race concordance on UK African-Caribbeans' comfort in disclosing depression. Methods: 160 African-Caribbean and 160 white British subjects, stratified by gender and history of depression, participated in simulated depression consultations with video-recorded doctors. Doctors were stratified by black or white race, gender and a high (HPC) or low patient-centred (LPC) communication style, giving a full 2. ×. 2. ×. 2 factorial design. Afterwards, participants rated aspects of doctors' communication style, their comfort in disclosing depression and treatment preferences. Results: Race concordance had no impact on African-Caribbeans' comfort in disclosing depression. However a HPC versus LPC communication style made them significantly more positive about their interactions with doctors (p = 0.000), their overall comfort (p = 0.003), their comfort in disclosing their emotional state (p = 0.001), and about considering talking therapy (p = 0.01); but less positive about considering antidepressant medication (p =0.01). Conclusion: Doctors' communication style was shown to be more important than patient race or race concordance in influencing African Caribbeans' depression consultation experiences. Changing doctors' communication style may help reduce disparities in depression care. Practice Implications: Practitioners should cultivate a HPC style to make African-Caribbeans more comfortable when disclosing depression, so that it is less likely to be missed.