Relative Disparity Research Articles

Increasing Disparity in Colorectal Cancer Incidence and Mortality Among African Americans and Whites: A State's Experience.

Objectives: To measure disparities between African Americans and whites in colorectal cancer incidence and mortality rates between 1995-2006 in Wisconsin. Methods: Cancer incidence data were obtained from the Wisconsin Cancer Reporting System. Cancer mortality data were accessed from the SEER. Trends in incidence and mortality rates were calculated and changes in relative disparity were measured using rate ratios. Results: The relative disparity in incidence grew from 1.0 in 1995 and 1.3 in 2006. The relative disparity in death rates for African Americans widened as well, from 1.2 to 1.5. Conclusion: A persistent and widening colorectal cancer racial disparity exists.

Magnetic property-texture relationships in galfenol rolled sheet stacks

Recent results in the area of galfenol (iron-gallium) alloy rolled sheet have yielded significant Goss ({110}<001>∥ rolling direction [RD]) texture development and large strain values, > 250 ppm. Goss-textured grain growth is promoted by the use of a grain boundary pinning second-phase particle. After multistage rolling and subsequent heat treatment, Goss grain areas as large as 125 cm2 develop in the RD–transverse direction (TD) plane. Goss grain <100> directions are typically within 15° of the RD inside these grains. Fully processed sheets were sectioned and bonded together to produce laminated stacks. Grain oriented and nongrain oriented stacks were characterized magnetically. Plotting strain data against H-field for both an Oriented Stack (OS) and a Nonoriented Stack (NonOS) yielded saturation stain values of 215 ppm and 70 ppm, at 48.3 MPa prestress, respectively. Magnetostrictive strain coefficient, d33, values of 20 nm/A and 4 nm/A were calculated for the OS and NonOS, respectively. Saturation magnetization values were found to be 1.3 T and 1.2 T for the OS and NonOS. Electron Backscatter Diffraction (EBSD) analysis was performed on cross sections of each laminated stack. EBSD mapping showed a large relative disparity in average grain size, taken from cross sections, of 470 μm and 84 μm for the OS and NonOS. Pole figures, contoured at a half-width of 10°, were analyzed and clearly show a high degree of Goss texture in the OS and a lack of any strong texture in the NonOS. The OS generated a maximum Multiple of Mean Uniform Density value > 16 while the NonOS produced a value < 2.

On the road to invariant object recognition: How cortical area V2 transforms absolute to relative disparity during 3D vision

Invariant recognition of objects depends on a hierarchy of cortical stages that build invariance gradually. Binocular disparity computations are a key part of this transformation. Cortical area V1 computes absolute disparity, which is the horizontal difference in retinal location of an image in the left and right foveas. Many cells in cortical area V2 compute relative disparity, which is the difference in absolute disparity of two visible features. Relative, but not absolute, disparity is invariant under both a disparity change across a scene and vergence eye movements. A neural network model is introduced which predicts that shunting lateral inhibition of disparity-sensitive layer 4 cells in V2 causes a peak shift in cell responses that transforms absolute disparity from V1 into relative disparity in V2. This inhibitory circuit has previously been implicated in contrast gain control, divisive normalization, selection of perceptual groupings, and attentional focusing. The model hereby links relative disparity to other visual functions and thereby suggests new ways to test its mechanistic basis. Other brain circuits are reviewed wherein lateral inhibition causes a peak shift that influences behavioral responses.

Sexual dimorphism in a dioecious population of the wind-pollinated herb Mercurialis annua: the interactive effects of resource availability and competition.

Male-biased sex allocation commonly occurs in wind-pollinated hermaphroditic plants, and is often positively associated with size, notably in terms of height. Currently, it is not well established whether a corresponding pattern holds for dioecious plants: do males of wind-pollinated species exhibit greater reproductive allocation than females? Here, sexual dimorphism is investigated in terms of life history trade-offs in a dioecious population of the wind-pollinated ruderal herb Mercurialis annua. The allocation strategies of males and females grown under different soil nutrient availability and competitive (i.e. no, male or female competitor) regimes were compared. Male reproductive allocation increased disproportionately with biomass, and was greater than that of females when grown in rich soils. Sexual morphs differentially adjusted their reproductive allocation in response to local environmental conditions. In particular, males reduced their reproductive allocation in poor soils, whereas females increased theirs, especially when competing with another female rather than growing alone. Finally, males displayed smaller above-ground vegetative sizes than females, but neither nutrient availability nor competition had a strong independent effect on relative size disparities between the sexes. Selection appears to favour plasticity in reproductive allocation in dioecious M. annua, thereby maintaining a relatively constant size hierarchy between sexual morphs. In common with other dioecious species, there seems to be little divergence in the niches occupied by males and females of M. annua.

Objects can be localized at positions that are inconsistent with the relative disparity between them

The presence of a more distant object helps judge an object's position in depth. To find out why, we examined whether misjudging a distant cube's location induces a corresponding misjudgment of a nearer sphere's location. Various configurations of a distant cube and a near sphere were presented in total darkness. Each configuration was presented twice: in one presentation, subjects localized the sphere with their unseen index finger, and in the other presentation, they localized the cube in the same way. Three cube sizes were used. Most subjects judged a larger cube to be nearer than a smaller one that was at the same position. For about half of the subjects, cube size had a significantly smaller effect on the judged distance of the sphere in terms of target vergence. Thus, the distance between the judged positions of the two objects was inconsistent with the relative disparity between them. This contradicts claims that the furthest object is localized and used as an anchor point for distance judgments based on correctly perceived relative disparity.

Persistence in breast cancer disparities between African Americans and whites in Wisconsin.

Breast cancer (BC) mortality is higher in African American women compared to white women despite having a lower incidence. The reasons for this remain unclear, despite decades of research. Reducing BC health disparities is a priority but has had limited success. To assess progress in eliminating breast cancer-related health disparities in Wisconsin by comparing trends in breast cancer outcomes in African American and white women from 1995 to 2006 and comparing results nationally. Age-adjusted breast cancer (BC) incidence and stage data from the Wisconsin Cancer Reporting System and age-adjusted mortality data from National Center of Health Statistics were used to evaluate trends in incidence and mortality from 1995 to 2006 for African Americans and whites. The relative disparity was evaluated by rate ratios. Trends in distribution of in situ vs malignant disease were examined. National trend data were obtained from the National Cancer Institute (NCI) Surveillance, Epidemiology and End Results (SEER) database. Age-adjusted incidence decreased 10% in Wisconsin compared to 7% nationally. Incidence of BC was lower in African American compared to white women. BC mortality in African American women declined in Wisconsin, but remained higher than white females. Age-adjusted mortality in Wisconsin declined approximately 23%, matching national trends. Non age-adjusted stage data trended toward a decrease in malignant, but increased in situ disease. Despite an overall reduction in BC mortality from 1995 to 2006, a persistent disparity in mortality remains for African American women, demonstrating no significant progress in reducing BC health disparities.

Increasing absolute mortality disparities by education in Finland, Norway and Sweden, 1971–2000

Background and objectivesStudies on socioeconomic health disparities often suffer from a lack of uniform data and methodology. Using high quality, census-linked data and sensible inequality measures, this study documents the...

Disparity Context Processing in the Primate Brain: And If the Question was Both ?What? and ?When??

Disparity Context Processing in the Primate Brain: And If the Question was Both ?What? and ?When??

Stereopsis Loses Dominance over Relative Size as Target Separation Increases

Binocular disparity produces less stereoscopic depth if the targets are separated by several degrees. It is thus possible that separation decreases the influence of stereopsis as a relative depth cue. Here, four experiments tested the strength of disparity in determining the direction of relative depth in the face of strongly conflicting relative size for a range of target separations. Under conditions of natural fixation-permitting sequential stereopsis-disparity dominated completely at small separations (0.42 degrees) but gradually gave way to relative size domination at large separations. However, when brief presentations prevented changes in fixation, disparity completely dominated at a separation of 0.5 degrees while relative size mostly dominated by 0.75 degrees - 1 degrees of separation. By varying target separation at different retinal eccentricities, we showed that separation per se was the critical factor in the dominance switch. Stereoacuity as a function of target separation for the same observers did not predict the switch from disparity to relative size. Stereoscopic dominance was found for the same small separations that are immune to stereoscopic reversals (Gillam, 1993 Perception 22 1025-1036). Our results suggest that relative disparity has a compulsory influence on perceived depth at small separations, suggesting a different mechanism from the one operating at larger separations.

Variable effects of prevalence correction of population denominators on differentials in myocardial infarction incidence: a record linkage study in Aboriginal and non-Aboriginal Western Australians

Objectives To investigate the impact of prevalence correction of population denominators on myocardial infarction (MI) incidence rates, rate ratios, and rate differences in Aboriginal vs. non-Aboriginal Western Australians aged 25–74 years during the study period 2000–2004. Study Design and Setting Person-based linked hospital and mortality data sets were used to estimate the number of prevalent and first-ever MI cases each year from 2000 to 2004 using a 15-year look-back period. Age-specific and -standardized MI incidence rates were calculated using both prevalence-corrected and -uncorrected population denominators, by sex and Aboriginality. Results The impact of prevalence correction on rates increased with age, was higher for men than women, and substantially greater for Aboriginal than non-Aboriginal people. Despite the systematic underestimation of incidence, prevalence correction had little impact on the Aboriginal to non-Aboriginal age-standardized rate ratios (6% and 4% underestimate in men and women, respectively), although the impact on rate differences was more marked (12% and 6%, respectively). The percentage underestimate of differentials was greater at older ages. Conclusion Prevalence correction of denominators, while more accurate, is difficult to apply and may add modestly to the quantification of relative disparities in MI incidence between populations. Absolute incidence disparities using uncorrected denominators may have an error >10%.

Declining child mortality and continuing racial disparities in the era of the Medicaid and SCHIP insurance coverage expansions.

We investigated trends in national childhood mortality, racial disparities in child mortality, and the effect of Medicaid and State Children's Health Insurance Program (SCHIP) eligibility expansions on child mortality. We analyzed child mortality by state, race, and age using the National Center for Health Statistics' multiple cause of death files over 20 years, from 1985 to 2004. Child mortality continued to decline in the United States, but racial disparities in mortality remained. Declines in child mortality (ages 1-17 years) were substantial for both natural (disease-related) and external (injuries, homicide, and suicide) causes for children of all races/ethnicities, although Black-White mortality ratios remained unchanged during the study period. Expanded Medicaid and SCHIP eligibility was significantly related to the decline in external-cause mortality; the relationship between natural-cause mortality and Medicaid or SCHIP eligibility remains unclear. Eligibility expansions did not affect relative racial disparities in child mortality. Although the study provides some evidence that public insurance expansions reduce child mortality, future research is needed on the effect of new health insurance on child health and on factors causing relative racial disparities.

Modulation of wild marigold (Tagetes minuta L.) phenophases towards the varying temperature regimes – a field study

Field experiments were conducted during 2007 and 2008 at experimental farm of Institute of Himalayan Bioresource Technology, (CSIR) Palampur (HP), India to study the performance of wild marigold (Tagetes minuta) under changing temperature regimes over the crop growth period. The established agroclimatic indices for temperature studied elsewhere in the domain viz., relative temperature disparity (RTD), growing degree days (GDD), heliothermal units (HTU) and photothermal units (PTU) were computed for different varied dates of sowing the crop. Distinct changes in weather parameters concomitant to different sowing time consequently caused significant variation in the performance of the crop. The results indicated that the early sown crop had longest crop span (224 days) than the late sown crop (102 days), from sowing to harvesting. The mean GDD accumulation from sowing to harvest ranged from 1378 to 2518°C days HTU from 6781 to 15706°C days hour and PTU from 17400 to 33052°C days hour. Total biomass, and content and yield of essential oil were correlated with different heat units calculated during the crop growth seasons. All the agroclimatic indices had positive correlations with biomass, oil content and oil yield. Thus, these indices seem to be effective in taking into account and expressing the effect of varying ambient temperature on the duration between the phenological events for comparing the crop response to the ambient temperature between different phenological stages.

Geographic and Racial Disparities In Multiple Myeloma Outcomes In the USA

AbstractAbstract 2557 Background:Stem cell transplantation, better supportive care, and the introduction of “novel agents”, particularly proteosome inhibitors and IMIDS, have improved survival in myeloma. However it is unclear if this improvement is uniform across various demographic subgroups. We present our analysis of a national database which still reveals significant disparities in the outcome of myeloma patients depending on their geographic location and race. Methods:Data on incidence and mortality was obtained from SEER database. Data on individual state myeloma rates was obtained from U.S. Cancer Statistics Working Group. Graphs were obtained from Cancer Mortality Maps and Graphs (NCI). Valuable measures of trends in cancer epidemiology include Annual Percent Change (APC) and Joinpoint analyses (JPC) which measure trends over a long period of time. Information regarding APC and JPC was obtained from the SEER Cancer Statistics Review. Disparities were calculated by the SEER health disparities calculator for differences in mortality across racial groups. Differences between the cohorts dichotomized at the introduction of novel agents (before and after 2000) were also calculated. Absolute mortality difference was assessed by the “Between Group Variance” (BGV). Relative disparity outcome across the 2 cohorts was assessed by “mean log deviation” (MLD) and the Theil index. Results:Overall age-adjusted mortality rate was 3.6/100,000 (2002-2006). 5-year relative survival rate was 37% (1999–2005). JPC trends stratified by race indicate a significantly increased JPC modeled incidence of myeloma in blacks to 12.4/100,000 until 1994, declining to 11.2/100,000 in 2006. The mortality rate, with a survival lag effect, also followed the trend in blacks, reaching a peak in 1996 at 7.9/100,000, whereas in whites, the JPC modeled trend was comparatively stable. Significant geographical variation in both incidence and mortality rates of myeloma were observed between different states (see maps). Washington DC and Alabama had the highest mortality rates of 5.3 (SE 0.43) and 4.4 (SE 0.14) per 100,000, whereas Hawaii and Florida had the lowest mortality rates of 2.25 (SE 0.18) and 3.09 (SE 0.05) per 100,000 respectively. The adjusted incidence rate within a state did not significantly correlate with its adjusted mortality rate. State wise comparisons were calculated between black and white races for mortality rates. Differences were found between mortality of blacks and whites in most of the states, which remained nearly constant across both the pre and post novel agent time cohorts. For example, in Washington DC the 1992–2000 and the 2000–2006 cohorts represented a mortality rate of 2.7 and 3.1 respectively for whites, and 7.9 and 7.2 respectively for blacks. An absolute difference in BGV of −21.5 for 2000–2006 cohort compared to 1992–2000 was observed whereas the relative disparity across the 2 cohorts indicated an MLD of −8.57 and a Theil index of -9.45; both indicating an absolute and relative decrease of mortality for the 2000–2006 cohort. When compared to 1992–2000, the percent change in mortality for 2000–2006 was −5.5 in whites and −9.2 in blacks. Conclusions:A wide variation in myeloma incidence and mortality was observed with respect to race and geography. While differences in incidence rates can be attributed to various epidemiological factors, the socioeconomic issues and differences in disease biology may explain the differences in mortality. Based on our results, we hypothesize that variations in clinical practice, due to lack of standardization may also contribute to the disparities in mortality. Previous studies have demonstrated comparable survival between blacks and whites given comparable treatment. While new approaches have contributed to improved mortality within the 2 studied cohorts of pre and post-novel agent era, the disparity in mortality between whites and blacks has remained constant. This is the first study to our knowledge, which has analyzed the inter-state disparities in mortality and disparities between black and white mortality before and after the introduction of novel agents for myeloma, in a representative sample of national dataset. Further studies are necessary to evaluate various factors that are responsible for the observed mortality differences.Age Adjusted Incidence rates 2006 [Display omitted] Age-adjusted Mortality rates 2006 [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Evidence for relative disparity matching in the perception of an ambiguous stereogram

To compute depth from binocular disparity, the visual system must correctly link corresponding points between two images, given multiple possible correspondences. Typically, model solutions to this problem use some form of local spatial smoothing, with many physiologically inspired models doing so implicitly, through the use of local cross-correlation-like procedures. In this paper we show that implicit smoothing, without the explicit consideration of relative disparity, cannot account for biases in the perception of a novel ambiguous stereo stimulus. Observers viewed a stereogram consisting of multiple strips of periodic random-dot patterns, perceived as either a slanted surface, or a triangular wedge in depth, and reported their perception in a 4AFC task. Biases in the perception of this stimulus are shown to depend upon the stimulus configuration in its entirety, and cannot be accounted for by low-level preferences for disparity sign. Such results are not consistent with local smoothing effects arising solely at the level of cross-correlation-like absolute disparity detectors. Instead, our results suggest the presence of smoothing constraints that consider the differences in disparity between neighboring image regions. These results further suggest that such smoothing generally biases matching toward solutions that minimize relative disparity, regardless of the presence of changes in disparity sign.

Stereoscopic Vision in the Absence of the Lateral Occipital Cortex

Both dorsal and ventral cortical visual streams contain neurons sensitive to binocular disparities, but the two streams may underlie different aspects of stereoscopic vision. Here we investigate stereopsis in the neurological patient D.F., whose ventral stream, specifically lateral occipital cortex, has been damaged bilaterally, causing profound visual form agnosia. Despite her severe damage to cortical visual areas, we report that DF's stereo vision is strikingly unimpaired. She is better than many control observers at using binocular disparity to judge whether an isolated object appears near or far, and to resolve ambiguous structure-from-motion. DF is, however, poor at using relative disparity between features at different locations across the visual field. This may stem from a difficulty in identifying the surface boundaries where relative disparity is available. We suggest that the ventral processing stream may play a critical role in enabling healthy observers to extract fine depth information from relative disparities within one surface or between surfaces located in different parts of the visual field.

Is There Progress toward Eliminating Racial/Ethnic Disparities in the Leading Causes of Death?

We examined changes in relative disparities between racial/ethnic populations for the five leading causes of death in the United States from 1990 to 2006. The study was based on age-adjusted death rates for four racial/ethnic populations from 1990-1998 and 1999-2006. We compared the percent change in death rates over time between racial/ethnic populations to assess changes in relative differences. We also computed an index of disparity to assess changes in disparities relative to the most favorable group rate. Except for stroke deaths from 1990 to 1998, relative disparities among racial/ethnic populations did not decline between 1990 and 2006. Disparities among racial/ethnic populations increased for heart disease deaths from 1999 to 2006, for chronic obstructive pulmonary disease deaths from 1990 to 1998, and for chronic lower respiratory disease deaths from 1999 to 2006. Deaths rates for the leading causes of death are generally declining; however, relative differences between racial/ethnic groups are not declining. The lack of reduction in relative differences indicates that little progress is being made toward the elimination of racial/ethnic disparities.

Relative Disparity in V2 Due to Inhibitory Peak Shifts of Absolute Disparity in V1

Relative Disparity in V2 Due to Inhibitory Peak Shifts of Absolute Disparity in V1

Relative disparity computation underlies the effects of surround area binocular correlation on depth perception

Relative disparity computation underlies the effects of surround area binocular correlation on depth perception

Modeling Stereopsis via Markov Random Field

Markov random field (MRF) and belief propagation have given birth to stereo vision algorithms with top performance. This article explores their biological plausibility. First, an MRF model guided by physiological and psychophysical facts was designed. Typically an MRF-based stereo vision algorithm employs a likelihood function that reflects the local similarity of two regions and a potential function that models the continuity constraint. In our model, the likelihood function is constructed on the basis of the disparity energy model because complex cells are considered as front-end disparity encoders in the visual pathway. Our likelihood function is also relevant to several psychological findings. The potential function in our model is constrained by the psychological finding that the strength of the cooperative interaction minimizing relative disparity decreases as the separation between stimuli increases. Our model is tested on three kinds of stereo images. In simulations on images with repetitive patterns, we demonstrate that our model could account for the human depth percepts that were previously explained by the second-order mechanism. In simulations on random dot stereograms and natural scene images, we demonstrate that false matches introduced by the disparity energy model can be reliably removed using our model. A comparison with the coarse-to-fine model shows that our model is able to compute the absolute disparity of small objects with larger relative disparity. We also relate our model to several physiological findings. The hypothesized neurons of the model are selective for absolute disparity and have facilitative extra receptive field. There are plenty of such neurons in the visual cortex. In conclusion, we think that stereopsis can be implemented by neural networks resembling MRF.

A solution to the online guidance problem for targeted reaches: proportional rate control using relative disparity τ

We provide a solution to a major problem in visually guided reaching. Research has shown that binocular vision plays an important role in the online visual guidance of reaching, but the visual information and strategy used to guide a reach remains unknown. We propose a new theory of visual guidance of reaching including a new information variable, tau(alpha) (relative disparity tau), and a novel control strategy that allows actors to guide their reach trajectories visually by maintaining a constant proportion between tau(alpha) and its rate of change. The dynamical model couples the information to the reaching movement to generate trajectories characteristic of human reaching. We tested the theory in two experiments in which participants reached under conditions of darkness to guide a visible point either on a sliding apparatus or on their finger to a point-light target in depth. Slider apparatus controlled for a simple mapping from visual to proprioceptive space. When reaching with their finger, participants were forced, by perturbation of visual information used for feedforward control, to use online control with only binocular disparity-based information for guidance. Statistical analyses of trajectories strongly supported the theory. Simulations of the model were compared statistically to actual reaching trajectories. The results supported the theory, showing that tau(alpha) provides a source of information for the control of visually guided reaching and that participants use this information in a proportional rate control strategy.