Disparate Measures Research Articles

Quantitative heterodonty in Crocodylia: assessing size and shape across modern and extinct taxa.

Heterodonty in Crocodylia and closely related taxa has not been defined quantitatively, as the teeth rarely have been measured. This has resulted in a range of qualitative descriptors, with little consensus on the condition of dental morphology in the clade. The purpose of this study is to present a method for the quantification of both size- and shape-heterodonty in members of Crocodylia. Data were collected from dry skeletal and fossil specimens of 34 crown crocodylians and one crocodyliform, resulting in 21 species total. Digital photographs were taken of each tooth and the skull, and the margins of both were converted into landmarks and semilandmarks. We expressed heterodonty through Foote’s morphological disparity, and a principal components analysis quantified shape variance. All specimens sampled were heterodont to varying degrees, with the majority of the shape variance represented by a ‘caniniform’ to ‘molariform’ transition. Heterodonty varied significantly between positions; size undulated whereas shape was significantly linear from mesial to distal. Size and shape appeared to be primarily decoupled. Skull shape correlated significantly with tooth shape. High size-heterodonty often correlated with relatively large caniniform teeth, reflecting a prioritization of securing prey. Large, highly molariform, distal teeth may be a consequence of high-frequency durophagy combined with prey size. The slender-snouted skull shape correlated with a caniniform arcade with low heterodonty. This was reminiscent of other underwater-feeding tetrapods, as they often focus on small prey that requires minimal processing. Several extinct taxa were very molariform, which was associated with low heterodonty. The terrestrial peirosaurid shared similarities with large modern crocodylian taxa, but may have processed prey differently. Disparity measures can be inflated or deflated if certain teeth are absent from the tooth row, and regression analysis may not best apply to strongly slender-snouted taxa. Nevertheless, when these methods are used in tandem they can give a complete picture of crocodylian heterodonty. Future researchers may apply our proposed method to most crocodylian specimens with an intact enough tooth row regardless of age, species, or rearing conditions, as this will add rigor to many life history studies of the clade.

Disruption of motor imagery performance following inhibition of the left inferior parietal lobe

The left inferior parietal lobe (IPL), a brain region localized to the ventro-dorsal stream, is known to be critical to motor imagery (MI) performance. Yet its specific role in processes underlying MI, namely the generation, maintenance, manipulation, and controllability of motor images, is conflicting in the literature. To determine the specific role of the left IPL in MI, the current study sought to examine the effect inhibition of the left IPL has on performance on two disparate measures thought to probe different MI processes within the same participants. Participants (N = 31) completed the hand laterality judgment task (HLJT), employed to probe processes related to manipulation and controllability, and mental chronometry, employed to probe processes related to generation and maintenance, after receiving either inhibitory transcranial magnetic stimulation to the left IPL (Active-TMS group), or with the coil angled away from the scalp (Sham group). Impaired performance on the HLJT was observed following active TMS relative to sham. Similar mental chronometry performance resulted regardless of left IPL inhibition. In showing that inhibition of the left IPL selectively disrupted performance on the HLJT but not mental chronometry, our findings indicate that the left IPL is specifically involved in image manipulation and controllability during MI. Ultimately, the current study extends our understanding of the role of the left IPL in MI.

From words to action: measuring health inequalities to "leave no one behind"Da retórica à ação: mensurar as desigualdades em saúde para não deixar ninguém atrás

RESUMENLa equidad en salud es un principio rector de la acción en salud pública –cuyo noble propósito es construir sociedades más saludables y sostenibles y, al mismo tiempo, más justas e inclusivas. Ello se refleja en el compromiso mundial por ‘no dejar a nadie atrás’ que preside la Agenda 2030 para el desarrollo sostenible, aunque en ninguna de sus 169 metas se establezca ni conceptual ni cuantitativamente la reducción de desigualdades en salud. Reconociendo la urgencia de trascender la retórica y avanzar consecuentemente en la formulación y puesta en marcha de políticas sociales y de salud pro-equitativas –de lo local a lo global–, en este informe especial se revisan las bases conceptuales y metodológicas para el abordaje de la equidad en salud, se vinculan explícitamente en una propuesta instrumental y práctica que promueve el uso analítico de los datos administrativos disponibles desagregados subnacionalmente para informar la toma de decisiones en esa dirección, y se concluye planteando la necesidad de institucionalizar la medición, análisis y monitoreo de las desigualdades sociales en salud para crear efectivamente capacidades nacionales para actuar sobre los determinantes sociales y ambientales de la salud y rendir cuentas sobre el compromiso de no dejar a nadie atrás en el camino hacia el desarrollo sostenible, la salud universal y la justicia social.

Associations of local-area walkability with disparities in residents' walking and car use

Research has examined spatial distribution of physical activity, mostly focusing on between-area differences by examining associations of area-level walkability measures with physical activity. Within-area distribution is also relevant, since larger disparities in physical activity within an area can contribute to greater inequalities in health. However, associations of within-area disparity in walking and walkability have been examined only at a large geographical scale (city level). This cross-sectional study examined associations of local-area walkability measures with within-area disparities in residents' walking and car use, using data collected in the 2009 South-East Queensland Travel Survey in Australia. For each Statistical Area 2 (SA2), we calculated disparity indices of the duration of walking and car use among participants aged 18–84 years, using Gini coefficients. Linear regression examined associations of the disparity measures with population density, street connectivity, and Walk Score. Analyses were conducted for 196 SA2s, which contained 15,895 participants. Higher walkability was associated with lower levels of disparity in walking and higher levels of disparity in car use, regardless of the measures used. Each one-SD increment in Walk Score was associated with a 0.64 lower SD in walking disparity and a 0.50 higher SD in car-use disparity, after adjusting for covariates. The associations remained significant after further adjusting for car ownership. Higher walkability is known to be associated with more walking and less car use. This study extends previous knowledge by showing that higher local-area walkability can be associated with less inequality in residents' walking and higher diversity in their car use.

Agent-based modeling to estimate exposures to urban air pollution from transportation: Exposure disparities and impacts of high-resolution data

Better understanding of the complex links between urban transportation, land use, air quality, and population exposure is needed to improve urban sustainability. A goal of this study was to develop an exposure modeling framework that integrates agent-based activity and travel simulation with air pollution modeling for Tampa, Florida. We aimed to characterize exposure and exposure inequality for traffic-related air pollution, and to investigate the impacts of high-resolution information on estimated exposure. To do these, we developed and applied a modeling framework that combines the DaySim activity-based travel demand model, the MATSim dynamic traffic assignment model, the MOVES mobile source emissions estimator, and the R-LINE dispersion model. Resulting spatiotemporal distributions of daily individual human activity and pollutant concentration were matched to analyze population and subgroup exposure to oxides of nitrogen (NOx) from passenger car travel for an average winter day in 2010. Four scenarios using data with different spatiotemporal resolutions were considered: a) high resolution for both activities and concentrations, b) low resolution for both activities and concentrations, c) high resolution for activities, but low resolution for concentrations, and d) vice versa. For the high-resolution scenario, the mean daily population exposure concentration of NOx from passenger cars was 10.2 μg/m3; individual exposure concentrations ranged from 0.2 to 145 μg/m3. Subgroup mean exposure was higher than the population mean for individuals living below-poverty (by ~16%), those with daily travel time over one hour (8%), adults aged 19–45 (7%), blacks (6%), Hispanics (4%), Asians (2%), combined other non-white races (2%), people from middle income households (2%), and residents of urban areas (2%). The subgroup inequality index (a measure of disparity) largely increased with concentration up to the 90th percentile level for these groups. At higher levels, disparities increased sharply for individuals from below poverty households, blacks, and Hispanics. Low-resolution simulation of both activities and concentrations decreased the exposure estimates by 10% on average, with differences ranging from eight times higher to ~90% lower.

Disparity Indices and Overweight: Frame of Reference.

Purpose: The purpose of this study was to compare state rankings of body mass index (BMI) among three different indices of income disparities (i.e., low-, middle-, and high-income thresholds) and BMI. One measure of disparities was based on national standards and the other measure was based on state-specific data.Methods: Data were from the 2016 Behavioral Risk Factor Surveillance System and analyzed in 2018. To assess differences between the two indices, Spearman Rank Order Correlation coefficient with a Bonferroni adjustment and kappa statistic were used.Results: Spearman rank-order correlation coefficient with a Bonferroni adjustment found that the two indices had a very weak monotonic relationship (ρ=0.11, p=0.46). The kappa value [κ (df=48)=0.02, p-value=0.43] revealed the indices were not concordant. The rankings of states based on national and state-specific disparity indices were distinctly different.Conclusion: Our study highlights the importance of choosing disparity indices. To analyze state similarities and differences, findings and interpretations are different when using a national standard applied to all states versus state-specific data as the frame of reference for the disparity index. Future research is needed to confirm the generalizability of our findings. In addition to income, our approach can be used with other sociodemographic variables such as age, race/ethnicity, sex, and education. The overall goal is to present a comprehensive and nuanced perspective of disparities contributing to the overweight/obesity epidemic.

Harmonizing Health Disparities Measurement.

Harmonizing Health Disparities Measurement.

Evaluating race and Hispanic origin responses of Medicaid participants using census data

Monitoring and addressing racial and ethnic disparities in health and health care require the collection and analysis of reliable demographic information. With the intention of improving the measurement and monitoring of disparities, certain provisions of the Patient Protection and Affordable Care Act (ACA) of 2010 require states to collect, report, and analyze data on demographic characteristics of applicants and participants in Medicaid and other federally supported programs. In this large-scale study we link Medicaid records to the Census 2000, the 2010 Census, and the American Community Survey for years 2001–2009 to explore the extent to which pre-ACA Medicaid administrative records matched self-reported race and Hispanic origin in Census Bureau data. Record linkage allows comparison of demographic, socioeconomic and neighborhood characteristics between Medicaid participants with matching and non-matching race and Hispanic origin in census. Identification of the groups most likely to have non-matching and missing race and Hispanic origin data in Medicaid relative to census can inform strategies to improve the quality of demographic data collected from the Medicaid population.

Variance Estimation and Confidence Intervals for 11 Commonly Used Health Disparity Measures.

There is increased interest in eliminating health disparities in the United States and worldwide. Broadly defined, health disparities refer to preventable inequalities in health status, such as cancer to ethnicity, socioeconomic status, gender, education, environment, and geographic locations. To make informed health policy decisions, it is essential to precisely measure the magnitude of disparities and assess trends over time. The Health Disparities Calculator (HD*Calc) is free statistical software that calculates 11 commonly used measures of health disparities and provides corresponding 95% CIs for the 11 measures using either an analytic method or a Monte Carlo simulation-based method; however, the derivation of SEs and coverage properties of the CIs have not been formally evaluated. We used simulation studies to assess the coverage properties of these CIs. We have also conducted bias analyses for measures implemented in HD*Calc using age-adjusted cancer incidence rates from national, state, and county level SEER data. The results of these analyses indicate that HD*Calc should be used with caution to construct CIs for some health disparity measures when the proportion of zero event counts is greater than 25%.

Surface continuity and discontinuity bias the perception of stereoscopic depth.

Binocular disparity signals can provide high acuity information about the positions of points, surfaces, and objects in three-dimensional space. For some stimulus configurations, however, perceived depth is known to be affected by surface organization. Here we examine the effects of surface continuity and discontinuity on such surface organization biases. Participants were presented with a series of random dot surfaces, each with a cumulative Gaussian form in depth. Surfaces varied in the steepness of disparity gradients, via manipulation of the standard deviation of the Gaussian, and/or the presence of differing forms of surface discontinuity. By varying the relative disparity between surface edges, we measured the points of subjective equality, where surfaces of differing steepness and/or discontinuity were perceptually indistinguishable. We compare our results to a model that considers sensitivity to different frequencies of disparity modulation. Across a series of experiments, the observed patterns of change in points of subjective equality suggest that perceived depth is determined by the integration of measures of relative disparity, with a bias toward sharp changes in disparity. Such disparities increase perceived depth when they are in the same direction as the overall disparity. Conversely, perceived depth is reduced by the presence of sharp disparity changes that oppose the sign of the overall depth change.

Nonlinear Distributional Mapping (NoDiM) for harmonization across amyloid-PET radiotracers

IntroductionThere is a growing need in clinical research domains for direct comparability between amyloid-beta (Aβ) Positron Emission Tomography (PET) measures obtained via different radiotracers and processing methodologies. Previous efforts to provide a common measurement scale fail to account for non-linearities between measurement scales that can arise from these differences. We introduce a new application of distribution mapping, based on well established statistical orthodoxy, that we call Nonlinear Distribution Mapping (NoDiM). NoDiM uses cumulative distribution functions to derive mappings between Aβ-PET measurements from different tracers and processing streams that align data based on their location in their respective distributions. MethodsUtilizing large datasets of Florbetapir (FBP) from the Alzheimer's Disease Neuroimaging Initiative (n = 349 female (%) = 53) and Pittsburgh Compound B (PiB) from the Harvard Aging Brain Study (n = 305 female (%) = 59.3) and the Australian Imaging, Biomarker & Lifestyle Flagship Study of Ageing (n = 184 female (%) = 53.3), we fit explicit mathematical models of a mixture of two normal distributions, with parameter estimates from Gaussian Mixture Models, to each tracer's empirical data. We demonstrate the accuracy of these fits, and then show the ability of NoDiM to transform FBP measurements into PiB-like units. ResultsA mixture of two normal distributions fit both the FBP and PiB empirical data and provides a strong basis for derivation of a transfer function. Transforming Aβ-PET data with NoDiM results in FBP and PiB distributions that are closely aligned throughout their entire range, while a linear transformation does not. Additionally the NoDiM transform better matches true positive and false positive profiles across tracers. DiscussionThe NoDiM transformation provides a useful alternative to the linear mapping advocated in the Centiloid project, and provides improved correspondence between measurements from different tracers across the range of observed values. This improved alignment enables disparate measures to be merged on to continuous scale, and better enables the use of uniform thresholds across tracers.

Compulsory community treatment to reduce readmission to hospital and increase engagement with community care in people with mental illness: a systematic review and meta-analysis

SummaryBackgroundCompulsory community treatment (CCT) aims to reduce hospital readmissions among people with mental illness. However, research examining the usefulness of CCT is inconclusive. We aimed to assess the effectiveness of CCT in reducing readmission and length of stay in hospital and increasing community service use and treatment adherence.MethodsFor this systematic review and meta-analysis, we searched three databases (PsycINFO, MEDLINE and Embase) for quantitative studies on CCT published in English between Jan 1, 1806, and Jan 4, 2018. We included both randomised and non-randomised designs that compared CCT with no CCT, and pre-post designs that compared patients before and after CCT. Studies were eligible if they had been peer-reviewed, if 50% or more of patients had severe mental illness, and if CCT was the intervention. Trials in which CCT was used in response to a criminal offence were excluded. We extracted data on study characteristics and length of follow-up, patient-level data on diagnosis, age, sex, race, and admission history, and outcomes of interest (readmission to hospital, inpatient bed-days, community service use, and treatment adherence) for meta-analysis, for which we extracted summary estimates. We used a random-effects model to compare disparate outcome measures and convert effect size statistics into standardised mean differences. This systematic review is registered with PROSPERO, number CRD42018086232.FindingsOf 1931 studies identified, 41 (2%) met inclusion criteria and had sufficient data for analysis. Before and after CCT comparisons showed significant large effects on readmission to hospital (standardised mean difference 0·80, 95% CI 0·53–1·08; I2=94·74), use of community services (0·83, 0·46–1·21; I2=87·26), and treatment adherence (2·12, 1·69–2·55; I2=0), and a medium effect on inpatient bed-days (0·66, 0·46–0·85; I2=94·12). Contemporaneous controlled comparison studies (randomised and non-randomised) showed no significant effect on readmission, inpatient bed-days, or treatment adherence, but a moderate effect on use of community services (0·38, 0·19–0·58; I2=96·92). A high degree of variability in study quality was found, with observational study ratings ranging from three to nine. Bias most frequently centred on poor comparability between CCT and control participants.InterpretationWe found no consistent evidence that CCT reduces readmission or length of inpatient stay, although it might have some benefit in enforcing use of outpatient treatment or increasing service provision, or both. Future research should focus on why some people do not engage with treatment offered and on enhancing quality of the community care available. Shortcomings of this study include high levels of variability between studies and variation in study quality.FundingNational Institute for Health Research.

Patterns of Racial/Ethnic Disparities and Prevalence in HIV and Syphilis Diagnoses Among Men Who Have Sex With Men, 2016: A Novel Data Visualization.

To describe disparities in HIV infection and syphilis among gay, bisexual, and other men who have sex with men (MSM) in US states through ratio-based measures and graphical depictions of disparities. We used state-level surveillance data of reported HIV and syphilis cases in 2015 and 2016, and estimates of MSM population sizes to estimate HIV and syphilis prevalence by race/ethnicity and rate ratios (RRs) and to visually display patterns of disparity and prevalence among US states. State-specific rates of new HIV diagnoses were higher for Black than for White MSM (RR range = 2.35 [Rhode Island] to 10.12 [Wisconsin]) and for Hispanic than for White MSM (RR range = 1.50 [Tennessee] to 5.78 [Pennsylvania]). Rates of syphilis diagnoses were higher for Black than for White MSM in 42 of 44 states (state RR range = 0.89 [Hawaii] to 17.11 [Alaska]). Scatterplots of HIV diagnosis rates by race showed heterogeneity in epidemic scenarios, even in states with similar ratio-based disparity measures. There is a widely disparate impact of HIV and syphilis among Black and Hispanic MSM compared with White MSM. Between-state variation suggests that states should tailor and focus their prevention responses to best address state data.

Treading water: respirometer choice may hamper comparative studies of energetics in fishes

Measuring the metabolic rate of animals is an essential part of understanding their ecology, behaviour and life history. Respirometry is the standard method of measuring metabolism in fish, but different respirometry methods and systems can result in disparate measurements of metabolic rate, a factor often difficult to quantify. Here we directly compare the results of two of the most common respirometry systems used in elasmobranch studies, a Steffensen-style flume respirometer and an annular static respirometer. Respirometry trials with juvenile lemon sharks Negaprion brevirostris were run in both systems under the same environmental conditions and using the same individuals. Relationships between metabolic rate, swimming speed, overall dynamic body acceleration (ODBA) and tail beat frequency (TBF) were compared between the two systems. The static respirometer elicited higher TBF and ODBA for a given swimming speed compared with the flume respirometer, although it produced relationships between kinematic parameters that were more similar to those observed in free-swimming animals. Metabolic rates and swimming speeds were higher for the flume respirometer. Therefore, although flume respirometers are necessary for many types of controlled laboratory studies, static respirometers may elicit lower stress and produce results that are more applicable to fish in wild systems.

A Robust Health Equity Metric

Background: Progress on health equity will require a robust metric. Such a metric must: allow meaningful comparisons across time and place; be calculable using health data typically available; measure health equity across all major forms of social exclusion; and be conceptually distinct from measures of health disparity. Method: This paper proposes a simple new health equity metric that meets all of these criteria. It is justified by a concept of health disutility as the distastefulness associated with one's health falling short of potential. The value of the health equity metric in a population sums up this distastefulness over the entire population. This health equity metric is conceptually distinct from a health disparities measure. It has a stable interpretation across different health measures as long as the underlying measures themselves are comparable. And it can be calculated using health data that are available in existing surveys of population health. As an example, the health equity metric is implemented using 2015 data from the Behavioral Risk Factor Surveillance Survey to show the rankings of US States by health equity. Findings: There is substantial variation across states, with the District of Columbia, Maryland and South Dakota showing the greatest health equity, and West Virginia, Arkansas and Kentucky exhibiting the least. Health equity is weakly correlated with one measure of health disparities. Interpretation. It is feasible to use a single health equity metric for consistent and objective measurement of health equity. Doing so will facilitate more rapid progress toward health equity. Funding Statement: The authors declare N/A. Declaration of Interests: The authors declare: none. Ethics Approval Statement: This study was deemed exempt from review by the UCLA Institutional Review Board.

Unequal before the law: Measuring legal gender disparities across the world

Several economies have laws that treat women differently from men. This study introduces the Women, Business and the Law dataset and explores the degree of such legal gender disparities across 167 economies around the world. This is achieved by constructing a simple measure of legal gender disparities to evaluate how countries perform. The average number of overall legal gender disparities across 167 economies is 17, ranging from a minimum of 2 to a maximum of 44. A high degree of legal gender disparities is found to be negatively associated with a wide range of outcomes.

Recent Changes in Prevention Funding to Areas With High Racial and Ethnic Disparities in Sexually Transmitted Disease Rates.

We examined changes in federal sexually transmitted disease funding allocations to areas with high racial/ethnic disparities in sexually transmitted diseases after the implementation of a funding formula in 2014. The funding formula increased prevention funding allocations to areas with high relative racial/ethnic disparities. Results were mixed for areas with high absolute disparities.

Statistical inferences of extended concentration indices for directly standardized rates.

The relative concentration index (RCI) and the absolute concentration index (ACI) have been widely used for monitoring health disparities with ranked health determinants. The RCI has been extended to allow value judgments about inequality aversion by Pereira in 1998 and by Wagstaff in 2002. Previous studies of the extended RCI have focused on survey sample data. This paper adapts the extended RCI for use with directly standardized rates (DSRs) calculated from population-based surveillance data. A Taylor series linearization (TL)-based variance estimator is developed and evaluated using simulations. A simulation-based Monte Carlo (MC) variance estimator is also evaluated as a comparison. Following Wagstaff's approach in 1991, we extend the ACI for use with DSRs. In all simulations, both the TL and MC methods produce valid variance estimates. The TL variance estimator has a simple, closed form that is attractive to users without sophisticated programming skills. The TL and MC estimators have been incorporated into a beta version of the National Cancer Institute's Health Disparities Calculator, a free statistical software tool that enables the estimation of 11 commonly used summary measures of health disparities for DSRs.

Micelle and Surface Tension of Double-Chain Cationic Surfactants.

Since the early 20th century, the slightly disparate measurements of a surfactant’s critical micelle concentration, via either surface tension or electrical conductivity, have been assumed one and the same. As a consequence, the possibility that micelles can adsorb at the air/water surface has been disregarded and has led to some abnormalities in the literature that remain as yet unresolved. In this paper, we closely examined the two critical concentrations for a double-chain cationic surfactant. We confirmed that the two concentrations represent two different physical phenomena. Furthermore, the results verified the existence of surface micelles, which are different from the bulk micelles. The formation of the surface micelles can be explained by the structural changes of the adsorption layer, which was also corroborated by molecular simulations. The findings open new challenges to examine the surface adsorption, which offers new insights into the molecular levels.

Rapid repeat pregnancy among women with intellectual and developmental disabilities: a population-based cohort study

Rapid repeat pregnancy within 12 months of a live birth is associated with adverse perinatal outcomes. We evaluated the risk for rapid repeat pregnancy among women with intellectual and developmental disabilities, with whom sharing of information about pregnancy planning and contraception may be inadequate. We accessed population-based health administrative data for all women with an index live birth in Ontario, Canada, for the period 2002-2013. We used modified Poisson regression to compare relative risks (RRs) for a rapid repeat pregnancy within 12 months of the index live birth in women with and without intellectual and developmental disabilities, first adjusting for demographic factors and then additionally adjusting for social, health and health care disparities. We compared 2855 women with intellectual and developmental disabilities and 923 367 women without such disabilities. At the index live birth, women with intellectual and developmental disabilities were more likely to be younger than 25 years of age (46.8% v. 18.2%) and to be disadvantaged on each measure of social, health and health care disparities. These women had a higher rate of rapid repeat pregnancy than those without such disabilities (7.6% v. 3.9%; adjusted RR 1.34, 95% confidence interval [CI] 1.18-1.54, after controlling for demographic factors). This risk was attenuated upon further adjustment for social, health and health care disparities (adjusted RR 1.00, 95% CI 0.87-1.14). Rapid repeat pregnancy, which was more common among women with intellectual and developmental disabilities, may be explained by social, health and health care disparities. To optimize reproductive health, multifactorial approaches to address the marginalization experienced by this population are likely needed.