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Paul W Mielke

Publications and source records attributed to Paul W Mielke.

At least 19 recordsLinked to original sources
PubMed2006

Potential lead on play surfaces: evaluation of the "PLOPS" sampler as a new tool for primary lead prevention.

This New Orleans study tested the "potential lead on play surfaces" (PLOPS) sampler, as a tool for measuring the potential lead (Pb) surface loading per area (e.g., microg/ft2) of the soil. The PLOPS is a cylindrical vinyl envelope filled with 1 kg (2.2 lbs) water. A wet wipe, the same type as used for floor wipes, is clipped to the bottom of the cylindrical vinyl envelope and placed on the soil and turned one quarter of a turn and back to obtain a sample. PLOPS samples paired with one conventional soil lead (SL) sample (amount of Pb per mass) up to 2.5 cm (1 in) deep were collected from 25 properties and 67-69 field sites before and after covering them with clean Mississippi River alluvial soil from the Bonnet Carré Spillway (BCS). Permutation methods were used to evaluate results. The correlation was 0.85 between Plops 1 and 2 and the agreement was 0.79 (P-values0.0000001, i.e., extreme). The averages of PLOPS duplicates were used to correlate PLOPS and SL. The simplest mathematical expressions are in the forms y=a+bxc and x=d+eyf, where x is PLOPS and y is SL. The results were:y=-7.42+0.408x0.97 and x=-43.74+24.85y0.69. The agreements were 0.61 and 0.62, respectively (P-value0.0000001). According to the relationship, when the PLOPS measure 40 microg/ft2, the predicted SL is 7.2 mg/kg. Also, when SL measures 400 mg/kg, 1508 microg/ft2 is predicted for PLOPS; therefore, SL concentration underestimates the potential for Pb exposure from the soil surface. The PLOPS tool provides a measurement that is comparable with interior floor wipes because it measures the amount of Pb per area a child is likely to encounter while at play on the soil surface.

Environmental Monitoring↗
PubMed2006

New Orleans soil lead (Pb) cleanup using Mississippi River alluvium: need, feasibility, and cost.

In New Orleans, LA prior to hurricane Katrina 20-30% of inner-city children had elevated blood Pb levels > or =10 microg/ dL and 10 census tracts had a median surface soil level of Pb >1000 mg/kg (2.5 times the U.S. standard). This project tests the feasibility of transporting and grading contaminated properties (n = 25) with 15 cm (6 in.) of clean Mississippi River alluvium from the Bonnet Carré Spillway (BCS) (median soil Pb content 4.7 mg/kg; range 1.7-22.8). The initial median surface soil Pb was 1051 mg/kg (maximum 19 627). After 680 metric tons (750 tons) of clean soil cover was emplaced on 6424 m2 (69 153 ft2), the median surface soil Pb decreased to 6 mg/kg (range 3-18). Interior entrance wipe samples were collected at 10 homes before and after soil treatment and showed a decreasing trend of Pb (p value = 0.048) from a median of 52 microg/ft2 to a median of 36 microg/ft2 (25th and 75th percentiles are 22 and 142 microg/ft2 and 12 and 61 microg/ft2, respectively). Average direct costs for properties with homes were $3,377 ($1.95 per square foot), with a range of $1,910-7,020, vs $2,622 ($0.61 per square foot), with a range of $2,400-3,040 for vacant lots. Approximately 40% (86,000) of properties in New Orleans are in areas of >400 mg Pb/kg soil and estimated direct costs for treatment are between $225.5 and $290.4 million. Annual costs of Pb poisoning in New Orleans are estimated at approximately $76 million in health, education, and societal harm. Urban accumulation of Pb is an international problem; for example, the new Government of Norway established a policy precedence for an isolated soil cleanup program at daycare centers, school playgrounds, and parks to protect children. New Orleans requires a community-wide soil cleanup program because of the extent and quantity of accumulated soil Pb. The post-Katrina benefits of reducing soil Pb are expected to outweigh the foreseeable costs of Pb poisoning to children returning to New Orleans.

Child↗
PubMed2006

Measures of effect size for chi-squared and likelihood-ratio goodness-of-fit tests.

A fundamental shift in editorial policy for psychological journals was initiated when the fourth edition of the Publication Manual of the American Psychological Association (1994) placed emphasis on reporting measures of effect size. This paper presents measures of effect size for the chi-squared and the likelihood-ratio goodness-of-fit statistic tests.

Chi-Square Distribution↗
PubMed2006

A measure of effect size for r x c contingency tables.

Goodman and Kruskal's tau measure of categorical association is advanced as a replacement for conventional measures of effect size for r x c contingency tables. Goodman and Kruskal's tau is an asymmetric measure of categorical association which is based entirely on the observed data and possesses a clear interpretation in terms of proportional reduction in error. Comparisons with conventional measures of effect size based on chi-squared such as Pearson's phi2, Tschuprow's T2, and Cramer's V2 demonstrate the advantages of employing tau as a measure of effect size.

Humans↗
PubMed2005

Multiple metal accumulation as a factor in learning achievement within various New Orleans elementary school communities.

In New Orleans, the elementary school system is divided into attendance districts with established boundaries that define student enrollment among schools. This study concerns environmental quality as defined by amount of soil metals (Pb, Zn, Cd, Ni, Mn, Cu, Co, Cr, and V) in attendance district elementary school communities (n = 111) paired with learning achievement as measured by individual test scores (n = 32,741) of students enrolled at each school. The Louisiana Educational Assessment Program (LEAP) 4th grade scores measure learning achievement for English language arts, social studies, mathematics, and science. The best fit between environmental quality and higher learning achievement is found to be inversely associated with the sum of the metals or multiple metal accumulations (MMA) in New Orleans communities. The P values for MMA partitions for ELA, SOC, MAT, and SCI are 0.57 x 10(-7), 0.29 x 10(-8), 0.41 x 10(-6), and 0.17 x 10(-8), respectively. Efforts to prevent childhood metal exposure should improve New Orleanians' learning achievement as measured by the LEAP scores and thereby enhance the socioeconomic situation in contaminated communities. This study establishes global relationships between LEAP scores in schools and soil metal concentrations in school neighborhoods. However, these data do not allow relating of the LEAP scores with metal levels for individual students.

Achievement↗
PubMed2005

Comparisons of continuous and discrete methods for combining probability values associated with matched-pairs t-test data.

Fisher's well-known continuous method for combining independent probability values from continuous distributions is compared with an exact discrete analog of Fisher's continuous method for combining independent probability values from discrete distributions using matched-pairs t-test data. Fisher's continuous method is shown to be inadequate for combining probability values from many discrete distributions, given the continuity assumption when discrete distributions are considered. Although Fisher's continuous method does not detect a well-documented effect among distributions, the exact discrete analog method clearly detects the effect.

Algorithms↗
PubMed2005

Exact and resampling probability values for measures of categorical variation and consensus.

When analyzing categorical data, it is often important to assess the magnitude of variation, or consensus, among observations in unordered categories. Utilizing the theory of partitions, exact solutions for five commonly used measures of categorical variation are presented. When the number of partitions is very large, resampling methods provide close approximations to exact probability values.

Algorithms↗
PubMed2005

A FORTRAN program for computing the exact variance of weighted kappa.

An algorithm and associated FORTRAN program are provided for the exact variance of weighted kappa. Program VARKAP provides the weighted kappa test statistic, the exact variance of weighted kappa, a Z score, one-sided lower- and upper-tail N(0,1) probability values, and the two-tail N(0,1) probability value.

Analysis of Variance↗
PubMed2005

Exact and resampling probability values for weighted kappa.

Permutation procedures to compute exact and resampling probability values for weighted kappa are described. Comparisons with asymptotic probability values demonstrate that exact permutation procedures are advantageous for sparse data sets, whereas resampling permutation procedures are appropriate for both sparse and nonsparse data sets.

Humans↗
PubMed2005

Resampling probability values for measures of ordinal variation and consensus.

Resampling permutation procedures provide good approximations to exact permutation procedures and are therefore the preferred alternative when large samples render exact tests intractable. Resampling permutation procedures are described for three measures of variation and the three corresponding measures of consensus among ordered categories.

Algorithms↗
PubMed2005

Changes of multiple metal accumulation (MMA) in New Orleans soil: preliminary evaluation of differences between survey I (1992) and survey II (2000).

Soil metal surveys were conducted in Baltimore, MD (1976-1979), Minnesota (1981-1988) and most recently, New Orleans, LA (1989-present). The unique characteristic of New Orleans is that it has two surveys; Survey I was completed in 1992 and Survey II was completed in 2000. This paper seeks to determine if there is a perceptible change in the amount of metals during less than a decade that separated these surveys. The Survey I collection was 4,026 samples stratified by 283 census tracts. All samples were collected in residential neighborhoods at least one block from a busy street. The Survey II collection was 5,467 samples stratified by 286 census tracts (plus City Park). The Survey II collection included busy streets as a category of samples. For comparison, the busy street category of 1,078 samples was excluded from Survey II for a total of 4,388 samples. The extraction methods of the two surveys used the same protocol for strength of acid (1 M HNO3), shaker-time (2 hours), and room temperature (approximately 22 degrees C). However, Survey II differed in amount of sample used in extraction. For Surveys I and II, 4.0g and 0.4g were used respectively. The same ICP-AES was used to measure 8 metals in both surveys. To evaluate the analytical results of the two methods, reference soi 1 samples (n=36) from the Wageningen Evaluating Programs for Analytical Laboratories, International Soil-analytical Exchange (WEPAL; ISE) were used. The relationship between the 4.0 and 0.4 g results were linear and the Survey I results were adjusted for sample:acid ratio. Further evaluation was done by creating interpolated Multiple Metal Accumulation (MMA) maps based on the median MMA for each census tract. A new map was created by dividing Survey II MMA by Survey I MMA. The ratio indicates increases of soil metals in the inner city and decreases of soil metals in the outlying areas of Metropolitan New Orleans. Comparing fresh parent alluvium from the Mississippi River with urban soil metal quantities demonstrates that the soils of New Orleans have undergone a massive accumulation of metals. The preliminary results provide ideas about methods needed to further evaluate the changes between these surveys.

Cities↗
PubMed2004

A measure of effect size for experimental designs with heterogeneous variances.

A recent trend in the psychological literature has been to include measures of effect size when reporting probability values. The several measures of effect size associated with the Student t test for two independent samples are appropriate only when the variances are homogeneous. In this paper, commonly used measures of effect size are considered and compared, using four data sets. A chance-corrected measure of effect size is provided for two or more treatment groups characterized by either homogeneous or heterogeneous variances.

Effect Modifier, Epidemiologic↗
PubMed2004

Exact goodness-of-fit tests for unordered equiprobable categories.

An algorithm and computer program to calculate exact goodness-of-fit tests for unordered categories with equal probabilities under the null hypothesis are presented. FORTRAN program EBGF utilizes partitions and multinomial weights to reduce computation times for Fisher's exact, exact chi-square, exact likelihood-ratio, exact Freeman-Tukey, and exact Cressie-Read goodness-of-fit tests.

Algorithms↗
PubMed2004

Asymptotic log-linear analysis: some cautions concerning sparse frequency tables.

Traditional asymptotic probability values resulting from log-linear analyses of sparse frequency tables are often much too large. Asymptotic probability values for chi-squared and likelihood-ratio statistics are compared to nonasymptotic and exact probability values for selected log-linear models. The asymptotic probability values are all too often substantially larger than the exact probability values for the analysis of sparse frequency tables. An exact nondirectional permutation method is presented to analyze combined independent multinomial distributions. Exact nondirectional permutation methods to analyze hypergeometric distributions associated with r-way frequency tables are confined to r = 2.

Chi-Square Distribution↗
PubMed2004

Combining probability values from independent permutation tests: a discrete analog of Fisher's classical method.

Permutation tests are based on all possible arrangements of observed data sets. Consequently, such tests yield exact probability values obtained from discrete probability distributions. An exact nondirectional method to combine independent probability values that obey discrete probability distributions is introduced. The exact method is the discrete analog to Fisher's classical method for combining probability values from independent continuous probability distributions. If the combination of probability values includes even one probability value that obeys a sparse discrete probability distribution, then Fisher's classical method may be grossly inadequate.

Humans↗
PubMed2003

Metal contamination of sediments and soils of Bayou Saint John: a potential health impact to local fishermen?

This research examines the pattern of sediment contamination of an urban bayou of New Orleans (formerly a natural waterway) and the potential for human exposure from consumption of fish caught in the bayou. Sediments and soils of Bayou Saint John were evaluated for lead (Pb), zinc (Zn), and cadmium (Cd). Sediment cores were collected at bridges (n = 130) and sites between the bridges (n = 303) of the bayou. In addition, soil samples (n = 66) were collected along the banks of the bayou. Sediments below the bridges contain significantly more (p-value approximately 10(-7)) Pb and Zn (medians of 241 and 230 mg kg(-1), respectively) than bayou sediments located between bridges (medians of 64 and 77 mg kg(-1), respectively). Sediments below bridges of the upper reaches of the bayou contain significantly larger amounts of metals (p < 10(-14) for Pb and Zn and p approximately 10(-8) for Cd) (medians of 329, 383 and 1.5, respectively) than sediments below bridges in the lower reaches of the bayou (medians of 43, 31 and 0.5 for Pb, Zn and Cd, respectively). Likewise, medians for sediments located between bridges contain significantly (p < 10(-14)) higher quantities of Pb, Zn and Cd (170, 203 and 1.8 mg kg(-1), respectively) in the upper bayou than Pb, Zn, and Cd (48, 32, and 0.8 mg kg(-1), respectively) in the lower reaches of the bayou. The potential risk for human exposure may be magnified by the fact that fishing generally occurs from the numerous bridges that cross the bayou. Poor and minority people do most of the fishing. Most people (87%) indicated they ate fish they caught from the Bayou.

Adolescent↗