Spatiotemporal Changes in the Slavery-Inequality Relationship: The Diffusion of the Legacy of Slavery.

Despite the persistence of relationships between historical racist violence and contemporary Black-White inequality, research indicates, in broad strokes, that the slavery-inequality relationship in the United States has changed over time. Identifying the timing of such change across states can offer insights into the underlying processes that generate Black-White inequality. In this study, we use integrated nested Laplace approximation models to simultaneously account for spatial and temporal features of panel data for Southern counties during the period spanning 1900 to 2018, in combination with data on the concentration of enslaved people from the 1860 census. Results provide the first evidence on the timing of changes in the slavery-economic inequality relationship and how changes differ across states. We find a region-wide decline in the magnitude of the slavery-inequality relationship by 1930, with declines traversing the South in a northeasterly-to-southwesterly pattern over the study period. Different paces in declines in the relationship across states suggest the expansion of institutionalized racism first in places with the longest-standing overt systems of slavery. Results provide guidance for further identifying intervening mechanisms-most centrally, the maturity of racial hierarchies and the associated diffusion of racial oppression across institutions, and how they affect the legacy of slavery in the United States.

Population change and the legacy of slavery.

Despite increasing evidence of a contemporary legacy of slavery in the US South, scholars do not have a clear empirical understanding of the ways in which demographic forces can alter local connections to racial histories. In this study, we examine the influence of long-run trends in population change on the relationship between historical slave concentration and contemporary black-white poverty inequality in the American South. We combine one century and a half of county-level population data, including estimates of the slave and total populations in 1860, estimates of black and white population change starting in 1880, and black-white poverty disparities from the 2011-2015 American Community Survey. Our results offer new empirical evidence regarding the enduring influence of racial histories over time, and suggest that white population increase between 1880 and 1910 was particularly influential in understanding the local connection between slave concentration and black-white inequality. Moreover, rather than disrupting the transmission of the legacy of slavery, results indicate that white population increase may have helped spread this legacy of racial inequality to other counties through diffusion processes. We find that while local historical legacies are persistent, they are not permanent, and population trends are a critical force shaping local racial inequality.

The Spatial Distribution of Poverty and the Long Reach of the Industrial Makeup of Places: New Evidence on Spatial and Temporal Regimes.

A wealth of research identifies industrial structure as a central correlate of place-level poverty and suggests that changes in and the clustering of industry contribute to the spatial clustering of poverty over time. However, few studies have investigated the spatial and temporal dimensions simultaneously, and none have effectively examined spatio-temporal interactions. Consequently, a core tenet of theory on poverty in place has not been adequately examined. To address this limitation, we explicitly test hypotheses about systematic variation in the poverty-industry relationship over time and across space using a new method to quantify dynamic associations by simultaneously accounting for spatial and temporal autocorrelation and relationship heterogeneity. The Upper Midwest is our study site given dramatic regional changes in dominant industries (i.e., manufacturing, services, and agriculture) and poverty during the past several decades. We find that the specific character of the poverty-industry relationship systematically varies along both the temporal and spatial dimensions: industry is more protective in certain periods than in others according to sector trends, and is more protective in certain places than others conditional on sector dependence. Our approach yields a more precise and reliable understanding of the long reach of local industrial structure on the spatial clustering of poverty.

Clinic access and teenage birth rates: Racial/ethnic and spatial disparities in Houston, TX.

Teenage motherhood is a pressing issue in the United States, and one that is disproportionately affecting racial/ethnic minorities. In this research, we examine the relationship between the distance to the nearest reproductive health clinic and teenage birth rates across all zip codes in Houston, Texas. Our primary data come from the Texas Department of State Health Services. We use spatial regression analysis techniques to examine the link between clinic proximity and local teenage birth rates for all females aged 15 to 19, and separately by maternal race/ethnicity. We find, overall, limited support for a connection between clinic distance and local teenage birth rates. However, clinics seem to matter most for explaining non-Hispanic white teenage birth rates, particularly in high-poverty zip codes. The racial/ethnic and economic variation in the importance of clinic distance suggests tailoring clinic outreach to more effectively serve a wider range of teenage populations. We argue social accessibility should be considered in addition to geographic accessibility in order for clinics to help prevent teenage pregnancy.

LINKING RACIAL COMPOSITION, BLACK-WHITE INEQUALITY, AND REGIONAL DIFFERENCE: THE ROLE OF MIGRATION.

The percent black-inequality relationship and the unique position of the South have been cornerstones of research on US racial inequality. Using an innovative methodological approach, I address how migration contributes to our understanding of the percent black-inequality relationship. I find that the educationally selective migration of blacks and whites significantly contributes to the percent black-inequality relationship via compositional changes. However, any explanatory power is limited to the non-South. Migration plays a role in understanding this relationship, yet processes related to black population concentration still generate black disadvantage anew, particularly within the South.

Multiracial identities, single race history: Contemporary consequences of historical race and marriage laws for racial classification.

This work interrogates the role of the law as an "actor" in the spatial patterning of racial classification. Laws governing racial intermarriage represent key ways that rigid distinctions between groups were codified. Critically, there is a great deal of state variation in these laws. We draw on a unique data set that combines samples from the 1990 and 2000 Census (5 percent IPUMS) and the 2009-2011 estimates from the American Community Survey with information on state-specific legal bans against intermarriage. Results from multilevel logistic and multinomial analyses indicate that a past of legal regulation is associated with a lower likelihood of a "mixed" classification for the offspring of black-white interracial unions, particularly in the 2009-11 period. Our results provide evidence that place-specific institutional legacies are imprinted on the classification choices made even in the midst of expanding options.

HISTORICAL RACIAL CONTEXTS AND CONTEMPORARY SPATIAL DIFFERENCES IN RACIAL INEQUALITY.

Research examining regional variation in the impact of racial concentration on black-white economic inequality assumes that the American South is distinct from the non-South because of its slavery history. However, slavery's influence on the relationship has not been directly examined nor has it been adequately theorized within the economic inequality literature. We assess whether the link between contemporary black concentration and poverty disparities is structured by historical racial context. We find that while there is contemporary racial inequality throughout the United States, inequality-generating processes vary spatially and in ways that are tied to the local historical racial context.

A Note on the Identification of Common Geographies.

Areal data have been used to good effect in a wide range of sociological research. One of the most persistent problems associated with this type of data, however, is the need to combine data sets with incongruous boundaries. To help address this problem, we introduce a new method for identifying common geographies. We show that identifying common geographies is equivalent to identifying components within a k-uniform k-partite hypergraph. This approach can be easily implemented using a geographic information system in conjunction with a simple search algorithm.

Where there's smoke: Cigarette use, social acceptability, and spatial approaches to multilevel modeling.

I contribute to understandings of how context is related to individual outcomes by assessing the added value of combining multilevel and spatial modeling techniques. This methodological approach leads to substantive contributions to the smoking literature, including improved clarity on the central contextual factors and the examination of one manifestation of the social acceptability hypothesis. For this analysis I use restricted-use natality data from the Vital Statistics, and county-level data from the 2005-9 ACS. Critically, the results suggest that spatial considerations are still relevant in a multilevel framework. In addition, I argue that spatial processes help explain the relationships linking racial/ethnic minority concentration to lower overall odds of smoking.

Storage Effects on Sample Integrity of Environmental Surface Sampling Specimens with Bacillus anthracis Spores.

The effect of packaging, shipping temperatures and storage times on recovery of Bacillus anthracis. Sterne spores from swabs was investigated. Macrofoam swabs were pre-moistened, inoculated with Bacillus anthracis spores, and packaged in primary containment or secondary containment before storage at -15°C, 5°C, 21°C, or 35°C for 0-7 days. Swabs were processed according to validated Centers for Disease Control/Laboratory Response Network culture protocols, and the percent recovery relative to a reference sample (T0) was determined for each variable. No differences were observed in recovery between swabs held at -15° and 5°C, (p ≥ 0.23). These two temperatures provided significantly better recovery than swabs held at 21°C or 35°C (all 7 days pooled, p ≤ 0.04). The percent recovery at 5°C was not significantly different if processed on days 1, 2 or 4, but was significantly lower on day 7 (day 2 vs. 7, 5°C, 102, p=0.03). Secondary containment provided significantly better percent recovery than primary containment, regardless of storage time (5°C data, p ≤ 0.008). The integrity of environmental swab samples containing Bacillus anthracis spores shipped in secondary containment was maintained when stored at -15°C or 5°C and processed within 4 days to yield the optimum percent recovery of spores.

A biofilm model developed to investigate survival and disinfection of Mycobacterium mucogenicum in potable water.

Water in healthcare environments can be a source for healthcare-associated infections (HAI). However, information on the exposure risk to opportunistic pathogens in potable water distribution systems (PWDS) is lacking. Laboratory studies characterizing the interaction of opportunistic pathogens with biofilms are needed to understand their role in water systems within healthcare facilities. A stable, repeatable, PWDS multi-species biofilm model comprising Sphingomonas paucimobilis, Methylobacterium sp., Delftia acidovorans, and Mycobacterium mucogenicum was developed in the CDC Biofilm Reactor (CBR), reaching 6 log(10) CFU cm(-2) within 6 days. The model was used to investigate the interaction of the opportunistic pathogen M. mucogenicum with the other species, and to determine the efficacy of monochloramine (NH(2)Cl) as a disinfectant against 2-week-old biofilms. Addition of 1 or 2 mg l(-1) NH(2)Cl resulted in the same or an increased log density of viable M. mucogenicum in the biofilm while inactivating some of the Proteobacteria. Although M. mucogenicum preferentially resided in the biofilm, NH(2)Cl exposure caused release of viable M. mucogenicum from the biofilm into the water. Additional studies with this model should determine if sodium hypochlorite has a comparative effect and if other nontuberculous mycobacteria (NTM) respond to NH(2)Cl similarly.

Outbreak of Mycobacterium chelonae infection associated with tattoo ink.

BACKGROUND: In January 2012, on the basis of an initial report from a dermatologist, we began to investigate an outbreak of tattoo-associated Mycobacterium chelonae skin and soft-tissue infections in Rochester, New York. The main goals were to identify the extent, cause, and form of transmission of the outbreak and to prevent further cases of infection. METHODS: We analyzed data from structured interviews with the patients, histopathological testing of skin-biopsy specimens, acid-fast bacilli smears, and microbial cultures and antimicrobial susceptibility testing. We also performed DNA sequencing, pulsed-field gel electrophoresis (PFGE), cultures of the ink and ingredients used in the preparation and packaging of the ink, assessment of source water and faucets at tattoo parlors, and investigation of the ink manufacturer. RESULTS: Between October and December 2011, a persistent, raised, erythematous rash in the tattoo area developed in 19 persons (13 men and 6 women) within 3 weeks after they received a tattoo from a single artist who used premixed gray ink; the highest occurrence of tattooing and rash onset was in November (accounting for 15 and 12 patients, respectively). The average age of the patients was 35 years (range, 18 to 48). Skin-biopsy specimens, obtained from 17 patients, showed abnormalities in all 17, with M. chelonae isolated from 14 and confirmed by means of DNA sequencing. PFGE analysis showed indistinguishable patterns in 11 clinical isolates and one of three unopened bottles of premixed ink. Eighteen of the 19 patients were treated with appropriate antibiotics, and their condition improved. CONCLUSIONS: The premixed ink was the common source of infection in this outbreak. These findings led to a recall by the manufacturer.

Variability of Burkholderia pseudomallei strain sensitivities to chlorine disinfection.

Burkholderia pseudomallei is a select agent and the causative agent of melioidosis. Variations in previously reported chlorine and monochloramine concentration time (Ct) values for disinfection of this organism make decisions regarding the appropriate levels of chlorine in water treatment systems difficult. This study identified the variation in Ct values for 2-, 3-, and 4-log(10) reductions of eight environmental and clinical isolates of B. pseudomallei in phosphate-buffered water. The greatest calculated Ct values for a 4-log(10) inactivation were 7.8 mg.min/liter for free available chlorine (FAC) at pH 8 and 5 degrees C and 550 mg.min/liter for monochloramine at pH 8 and 5 degrees C. Ionic strength of test solutions, culture hold times in water, and cell washing were ruled out as sources of the differences in prior observations. Tolerance to FAC was correlated with the relative amount of extracellular material produced by each isolate. Solid-phase cytometry analysis using an esterase-cleaved fluorochrome assay detected a 2-log(10)-higher level of organisms based upon metabolic activity than did culture, which in some cases increased Ct values by fivefold. Despite strain-to-strain variations in Ct values of 17-fold for FAC and 2.5-fold for monochloramine, standard FAC disinfection practices utilized in the United States should disinfect planktonic populations of these B. pseudomallei strains by 4 orders of magnitude in less than 10 min at the tested temperatures and pH levels.

Enhanced high copy number plasmid maintenance and heterologous protein production in an Escherichia coli biofilm.

Escherichia coli has been widely used for heterologous protein production (HPP). To determine whether a biofilm environment could benefit E. coli HPP using high copy number plasmids, we compared plasmid maintenance and HPP by E. coli ATCC 33456 containing plasmid pEGFP (a pUC family vector) cultivated in biofilms and in suspended culture. Cells were grown with or without antibiotic selective pressure in flow cells or chemostats for up to 6 days. In biofilms, antibiotic selective pressure increased the plasmid copy number (PCN), but by 144 h, biofilms grown in antibiotic-free media had comparable plasmid concentrations. In the chemostat, the PCN declined steadily, although 100 ppm ampicillin in the medium slowed the rate of plasmid loss. Production of green fluorescent protein (GFP), a representative heterologous protein, was quantified by flow cytometry. In biofilms, at ampicillin concentrations >or=33 ppm, strongly fluorescent cells comprised more than half of the population by 48 h. In the chemostat, more than 50% of the population was non-fluorescent by 48 h in media containing 100 ppm ampicillin, and strongly fluorescent cells were <10% of the population. Biofilm structure was determined by confocal microscopy. Maximum biofilm thickness ranged from 30 to 45 microns, with no significant changes in biofilm structure after 48 h. Plasmid multimer percentages were similar to inocula for cells cultivated in either biofilms or the chemostat. The results indicate that the biofilm environment enhanced both plasmid maintenance and cellular GFP concentrations, and that low levels of antibiotic increased the beneficial effect.

Influences of biofilm structure and antibiotic resistance mechanisms on indirect pathogenicity in a model polymicrobial biofilm.

Indirect pathogenicity (IP), the commensal protection of antibiotic-sensitive pathogens by resistant microorganisms of low intrinsic virulence, can prevent the eradication of polymicrobial infections. The contributions of antibiotic resistance mechanisms and biofilm structure to IP within polymicrobial biofilms were investigated using a model two-member consortium. Escherichia coli ATCC 33456 was transformed with vectors conferring either ampicillin or spectinomycin resistance, creating two distinct populations with different resistance mechanisms. Each strain alone or the consortium was grown as biofilms in flow cells and planktonically in chemostats. Comparisons in survival and activity were made on the basis of MICs and minimum biofilm preventative concentrations, a newly introduced descriptor. In ampicillin-containing medium, commensal interactions were evident during both modes of cultivation, but the sensitive strain experienced a greater benefit in the chemostat, indicating that the biofilm environment limited the commensal interaction between the Amp(r) and Spt(r) strains. In spectinomycin-containing medium, growth of the sensitive strain in chemostats and biofilms was not aided by the resistant strain. However, green fluorescent protein expression by the sensitive strain was greater in mixed-population biofilms (9% +/- 1%) than when the strain was grown alone (2% +/- 0%). No comparable benefit was evident during growth in the chemostat, indicating that the biofilm structure contributed to enhanced activity of the sensitive strain.