Hundreds of municipalities and counties across the United States have proposed or implemented immigration policies at the local level, ranging from "sanctuary" policies to those designed to exclude undocumented immigrants. Data collected on these policies are presented, and statistically analyzed at the municipal level to interrogate existing hypotheses about factors driving these policy decisions. Municipalities experiencing rapid growth of their foreign-born population and with a high percentage of owner-occupied housing are more likely to introduce exclusionary policies, whereas municipalities with better educated populations are more likely to adopt inclusionary policies. The location of municipalities in the U.S. South and outside central cities is also associated with exclusionary policies. Textual analysis of policy documents for selected municipalities provides insight into why similarly located places adopt contrasting policies. Local ordinances reflect contrasting local imaginaries of race, nation, and place. 157

Background: Use of 3-dimensional (3D) computed tomography (CT) preoperative planning and patient-specific instrumentation has been demonstrated to improve the accuracy of glenoid implant placement in total shoulder arthroplasty (TSA). The purpose of this study was to compare the accuracy of glenoid implant placement in primary TSA among different types of instrumentation used with the 3D CT preoperative planning. Methods: One hundred and seventy-three patients with end-stage glenohumeral arthritis were enrolled in 3 prospective studies evaluating patient-specific instrumentation and 3D preoperative planning. All patients underwent preoperative 3D CT planning to determine optimal glenoid component and guide pin position based on surgeon preference. Patients were placed into 1 of 5 instrument groups used for intraoperative guide pin placement: (1) standard instrumentation, (2) standard instrumentation combined with use of a 3D glenoid bone model containing the guide pin, (3) use of the 3D glenoid bone model combined with single-use patient-specific instrumentation, (4) use of the 3D glenoid bone model combined with reusable patient-specific instrumentation, and (5) use of reusable patient-specific instrumentation with an adjustable, reusable base. Postoperatively, all patients underwent 3D CT to compare actual versus planned glenoid component position. Deviation from the plan (in terms of orientation and location) was compared across groups on the basis of absolute differences and outlier analysis. Univariable and multivariable comparisons were performed. As the initial analyses showed no significant differences in preoperative factors or in deviation from the plan between Groups 1 and 2 or between Groups 4 and 5 across studies, the final analysis was across 3 major treatment groups: standard instrumentation (Groups 1 and 2), single-use patient-specific instrumentation (Group 3), and reusable patient-specific instrumentation (Groups 4 and 5). Results: In nearly all comparisons, there were no significant differences in the deviation from the plan (absolute differences or outlier frequency) for glenoid implant orientation or location across the 3 major treatment groups. Conclusions: This study did not demonstrate that any type of patient-specific instrumentation resulted in consistent differences in accuracy of glenoid implant placement in primary TSA with 3D CT preoperative planning. Surgeons have multiple patient-specific instrumentation options available for improving accuracy of glenoid implant placement when compared with 2D imaging without patient-specific instrumentation. Level of Evidence Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

TIGER/Line shapefiles from the United States Census Bureau are commonly used for the mapping and analysis of US demographic trends. The tigris package provides a uniform interface for R users to download and work with these shapefiles. Functions in tigris allow R users to request Census geographic datasets using familiar geographic identifiers and return those datasets as objects of class "Spatial*DataFrame". In turn, tigris ensures consistent and high-quality spatial data for R users' cartographic and spatial analysis projects that involve US Census data. This article provides an overview of the functionality of the tigris package, and concludes with an applied example of a geospatial workflow using data retrieved with tigris.

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Racial and ethnic diversity in the United States is on the rise, as the country is projected to no longer have a racial majority by the mid-2040s. Much of this diversity is found in the United States' large metropolitan areas, where it manifests itself unevenly. While some metropolitan neighbourhoods are growing highly diverse, others remain segregated by race and ethnicity. This paper introduces a framework for exploring the geography of neighbourhood diversity in US metropolitan areas, and defines the diversity gradient, a visual representation of how diversity varies with distance from the urban core. Analysis of the geography of metropolitan diversity from 1990 to 2010 reveals that the greatest increases in diversity are found in the suburbs and outlying areas, where diversity now peaks in many large metropolitan areas. Additional spatial analyses of neighbourhood diversity in Chicago and Dallas-Fort Worth show that clustering of highly diverse neighbourhoods has shifted to the suburbs from close-in urban areas, where many segregated and low-diversity neighbourhoods persist.

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Recent electoral research has claimed that individuals in the United States are self‐segregating along political lines. In this paper, I use the Twin Cities, Minnesota, metropolitan area as a case study to test for the presence of political segregation through statistical and spatial analyses of electoral data from 1992 to 2012. I find that while segregation by partisan voting at the individual level is comparatively low, it has increased during the study period, and there exists substantial spatial clustering in voting patterns at aggregate levels. These distinct electoral divides between central city and exurb suggest spatial sorting of the electorate in the metropolitan area.