Common power laws for cities and spatial fractal structures.

City-size distributions are known to be well approximated by power laws across a wide range of countries. But such distributions are also meaningful at other spatial scales, such as within certain regions of a country. Using data from China, France, Germany, India, Japan, and the United States, we first document that large cities are significantly more spaced out than would be expected by chance alone. We next construct spatial hierarchies for countries by first partitioning geographic space using a given number of their largest cities as cell centers and then continuing this partitioning procedure within each cell recursively. We find that city-size distributions in different parts of these spatial hierarchies exhibit power laws that are, again, far more similar than would be expected by chance alone-suggesting the existence of a spatial fractal structure.

Geospatial and Socioeconomic Factors Interact to Predict Management and Outcomes in Cleft Lip and Palate Surgery: A Single Institution Study of 740 Patients.

OBJECTIVE: Determine interactions between geospatial and socioeconomic factors influencing cleft lip and/or cleft palate (CL/P) management and outcomes. DESIGN: Retrospective review and outcomes analysis (n = 740). SETTING: Urban academic tertiary care center. PATIENTS: 740 patients undergoing primary (CL/P) surgery from 2009 to 2019. MAIN OUTCOMES MEASURES: Prenatal evaluation by plastic surgery, nasoalveolar molding, cleft lip adhesion, and age at CL/P surgery. RESULTS: Prenatal evaluation by plastic surgery was predicted by the interaction between higher patient median block group income and shorter patient distance from the care center (OR = 1.07, p = 0.022). Nasoalveolar molding was also predicted by the interaction between higher patient median block group income and shorter distance from the care center (OR = 1.28, p = 0.016), whereas cleft lip adhesion was predicted by higher patient median block group income alone (OR = 0.41, p < 0.001). Lower patient median block group income predicted later age at cleft lip (ß = -67.25, p = 0.011) and cleft palate (ß = -46.35, p = 0.050) repair surgery. CONCLUSIONS: Distance from the care center and lower median income by block group interacted to significantly predict prenatal evaluation by plastic surgery and nasoalveolar molding for patients with CL/P at a large, urban, tertiary care center. Patients living farthest from the care center who received prenatal evaluation by plastic surgery or who underwent nasoalveolar molding had higher median block group income. Future work will determine mechanisms perpetuating these barriers to care.

Improved retransplant outcomes: early evidence of the share35 impact.

BACKGROUND: Share 35 prioritizes offers of deceased donor livers to regional candidates with Model for End-Stage Liver Disease (MELD) ≥35 over local candidates with lower MELD scores. Analysis of Share35 has shown that overall 1- or 2-year post-transplant (LTx) outcomes have been unchanged while waitlist mortality has been reduced. However, these studies exclude retransplant (reLTx) recipients. This study aims to investigate the outcomes of liver retransplants in evaluating the impact of the Share35 policy. METHODS: A retrospective analysis of data from the United Network for Organ Sharing database over the period June 2011-June 2015 was performed. RESULTS: A total of 19,748 LTx and 312 reLTx recipients were identified. Of the LTx recipients, 9626 (48.7%) underwent transplant pre-Share 35 and 10,122 (51.3%) post-Share 35. 123 (39.4%) reLTx recipients underwent retransplantation pre-Share 35 and 189 (60.6%) post-Share 35. ReLTx recipients experienced improved 2-year graft survival post-Share 35 compared to pre-Share 35 (67% vs. 21.1%). Patient survival also improved at 2-years for reLTx recipients post-Share 35 compared to pre-Share 35 (69.2% vs. 33.1%). Transplant post-Share 35 was protective for both 2-year graft (HR = 0.669, CI = 0.454-0.985, p = 0.04) and patient (HR = 0.659, CI = 0.44-0.987, p = 0.003) survival. CONCLUSION: Share35 is associated with improved outcomes after retransplantation.

cDC1 coordinate innate and adaptive responses in the omentum required for T cell priming and memory.

In the peritoneal cavity, the omentum contains fat-associated lymphoid clusters (FALCs) whose role in response to infection is poorly understood. After intraperitoneal immunization with Toxoplasma gondii, conventional type 1 dendritic cells (cDC1s) were critical to induce innate sources of IFN-γ and cellular changes in the FALCs. Unexpectedly, infected peritoneal macrophages that migrated into the FALCs primed CD8+ T cells. Although T cell priming was cDC1 independent, these DCs were required for maximal CD8+ T cell expansion. An agent-based computational model and experimental data highlighted that cDC1s affected the magnitude of the proliferative burst and promoted CD8+ T cell expression of nutrient uptake receptors and cell survival. Thus, although FALCs lack the organization of secondary lymphoid organs, cDC1s resident in this tissue coordinate innate responses to microbial challenge and provide secondary signals required for T cell expansion and memory formation.

Clustering of unhealthy outdoor advertisements around child-serving institutions: a comparison of three cities.

Using GPS devices and digital cameras, we surveyed outdoor advertisements in Austin, Los Angeles and Philadelphia. GIS and hot spot analysis revealed that unhealthy ads were clustered around child-serving institutions in Los Angeles and Philadelphia but not in Austin. Multivariate generalized least square (GLS) regression models showed that percent black (p<0.04) was a significant positive predictor of clustering in Philadelphia and percent white (p<0.06) was a marginally significant negative predictor of clustering in Los Angeles after controlling for several land use variables. The results emphasize the importance of zoning and land use regulations to protect children from exposure to unhealthy commercial messages, particularly in neighborhoods with significant racial/ethnic minority populations.

Increased alcohol use after Hurricane Ike: The roles of perceived social cohesion and social control.

Hurricane Ike, the third costliest hurricane in US history, made landfall in the Galveston Bay Area in September, 2008. Existing literature postulates that maladaptive behavior such as increased alcohol use is often exhibited by disaster survivors in coping with both disaster-related traumatic events and post-disaster stressful events. In addition, it has also been postulated that survivors' perceptions of social cohesion and social control can potentially serve to moderate such behavior. The purpose of this paper is to study such hypotheses for Hurricane Ike. In particular, we investigate the following four hypotheses: (H1) There is an increase of alcohol use by survivors of Hurricane Ike in the Galveston Bay Area; (H2) There are positive associations between both Ike-related trauma and post-Ike stress events and the increase in alcohol use; (H3) There are negative associations between both perceived social cohesion and social control and the increase in alcohol use following Ike; and finally that (H4) perceived social cohesion and social control serve to moderate the associations between both Ike-related trauma and post-Ike stress events and increased alcohol use after Ike. Using public use survey-weighted data from the Galveston Bay Recovery Study (GBRS) of Ike survivors (N = 658), we tested these hypotheses using logistic regressions controlling for other key socioeconomic variables. Our results confirm H1 and H2. Hypotheses H3 and H4 are partially confirmed with respect to social control, but show that (i) there is a positive association between perceived social cohesion and the increase in alcohol use following Ike, and that (ii) while perceived social cohesion and social control do moderate the association between post-Ike stress events and increased alcohol use, they have no effect on the association between Ike-related trauma and increased alcohol use.

Discrete Choice Model of Food Store Trips Using National Household Food Acquisition and Purchase Survey (FoodAPS).

Where households across income levels shop for food is of central concern within a growing body of research focused on where people live relative to where they shop, what they purchase and eat, and how those choices influence the risk of obesity and chronic disease. We analyzed data from the National Household Food Acquisition and Purchase Survey (FoodAPS) using a conditional logit model to determine where participants shop for food to be prepared and eaten at home and how individual and household characteristics of food shoppers interact with store characteristics and distance from home in determining store choice. Store size, whether or not it was a full-service supermarket, and the driving distance from home to the store constituted the three significant main effects on store choice. Overall, participants were more likely to choose larger stores, conventional supermarkets rather than super-centers and other types of stores, and stores closer to home. Interaction effects show that participants receiving Supplemental Nutrition Assistance Program (SNAP) were even more likely to choose larger stores. Hispanic participants were more likely than non-Hispanics to choose full-service supermarkets while White participants were more likely to travel further than non-Whites. This study demonstrates the value of explicitly spatial discrete choice models and provides evidence of national trends consistent with previous smaller, local studies.

Geographic distribution of insufficient sleep across the United States: a county-level hotspot analysis.

INTRODUCTION: Insufficient sleep is associated with cardiometabolic risk and neurocognitive impairment. Determinants of insufficient sleep include many social and environmental factors. Assessment of geographic hot/coldspots may uncover novel risk groups and/or targets for public health intervention. The aim of this study was to discern geographic patterns in the first data set to include county-level sleep data. METHODS: The 2009 Behavioral Risk Factor Surveillance System was used. Insufficient sleep was assessed with a survey item and dichotomized. Data from n = 2231 counties were available. Tests for significant spatial concentrations of high/low levels of insufficient sleep (hotspots/coldspots) used the Getis-Ord G* statistic of local spatial concentration, chosen due to the nature of missing data. RESULTS: Eighty-four counties were hotspots, with high levels of insufficient sleep (P < .01), and 45 were coldspots, with low insufficient sleep (P < .01). Hotspots were found in Alabama (1 county), Arkansas (1), Georgia (1), Illinois (1), Kentucky (25), Louisiana (1), Missouri (4), Ohio (7), Tennessee (12), Texas (9), Virginia (6), and West Virginia (16). Coldspots were found in Alabama (1 county), Georgia (2), Illinois (6), Iowa (6), Michigan (2), Minnesota (1), North Carolina (1), Texas (7), Virginia (12), and Wisconsin (6). Several contiguous hotspots and coldspots were evident. Notably, the 17 counties with the highest levels of insufficient sleep were found in a contiguous set at the intersection of Kentucky, Tennessee, Virginia, and West Virginia (all P < .0002). CONCLUSIONS: Geographic distribution of insufficient sleep in the United States is uneven. Some areas (most notably parts of Appalachia) experience disproportionately high amounts of insufficient sleep and may be targets of intervention. Further investigation of determinants of geographic variability needs to be explored, which would enhance the utility of these data for development of public health campaigns.

Geographic Variation in Cold Ischemia Time: Kidney vs. Liver Transplantation in the United States, 2003-2011.

BACKGROUND: Regional variations in kidney and liver transplant outcomes have been reported, but their causes remain largely unknown. This study investigated variations in kidney and liver cold ischemia times (CITs) across Organ Procurement Organizations (OPO) as potential causes of variations in transplant outcomes. METHODS: This retrospective study analyzed the Standard Transplant Analysis and Research (STAR) data of deceased donor kidney (n=61,335) and liver (n=39,285) transplants performed between 2003 and 2011. CIT variations between the two types of organs were examined and compared. Factors associated with CIT were explored using multivariable regressions. Spearman's rank tests were used to associate CIT with graft failure at the OPO level. RESULTS: Significant CIT variations were found across OPOs for both organs (p < 0.05). The variation was particularly large for kidney CIT. Those OPOs with longer average kidney CIT were likely to have a lower graft survival rate (p=0.01). For liver, this association was insignificant (p=0.23). The regression analysis revealed sharp contrasts between the factors associated with kidney and liver CITs. High risk kidney transplant recipients and marginal kidneys were associated with longer average CIT. The reverse was true for liver transplants. CONCLUSIONS: Large variations in kidney CIT compared to liver CIT may indicate that there is a room to reduce kidney CIT. Reducing kidney CIT through managerial improvements could be a cost effective way to improve the current transplant system.

The Impact of Hospital Closures and Hospital and Population Characteristics on Increasing Emergency Department Volume: A Geographic Analysis.

Emergency visits are rising nationally, whereas the number of emergency departments is shrinking. However, volume has not increased uniformly at all emergency departments. It is unclear what factors account for this variability in emergency volume growth rates. The objective of this study was to test the association of hospital and population characteristics and the effect of hospital closures with increases in emergency department volume. The study team analyzed emergency department volume at New York State hospitals from 2004 to 2010 using data from cost reports and administrative databases. Multivariate regression was used to evaluate characteristics associated with emergency volume growth. Spatial analytics and distances between hospitals were used in calculating the predicted impact of hospital closures on emergency department use. Among the 192 New York hospitals open from 2004 to 2010, the mean annual increase in emergency department visits was 2.7%, but the range was wide (-5.5% to 11.3%). Emergency volume increased nearly twice as fast at tertiary referral centers (4.8%) and nonurban hospitals (3.7% versus urban at 2.1%) after adjusting for other characteristics. The effect of hospital closures also strongly predicted variation in growth. Emergency volume is increasing faster at specific hospitals: tertiary referral centers, nonurban hospitals, and those near hospital closures. This study provides an understanding of how emergency volume varies among hospitals and predicts the effect of hospital closures in a statewide region. Understanding the impact of these factors on emergency department use is essential to ensure that these populations have access to critical emergency services.

Communities of color? Client-to-client racial concordance in the selection of mental health programs for Caucasians and African Americans.

A discrete-choice logit model was applied to study the determinants of mental health provider choice using data from a large urban county in the Northeast US. The study subjects were 9,544 adult Medicaid recipients who received outpatient treatment from the 20 Community Mental Health Center (CMHC) programs in 2001. In addition to a conventional set of variables representing client and provider characteristics, the regression model included several interaction terms to examine whether racial concordance level among patients influences the choice of an outpatient program. The results revealed that racial concordance among the clients seems to be a factor in choosing a program. In particular, Caucasian clients are much more likely to select a program with a higher percentage of Caucasian clients, even though they have to travel further. More generally, our results suggest that program choice may be driven more by the racial composition of the clients served than by spatial proximity to the program.

Comparison and verification of BSE surveillance in USA and Japan.

OBJECTIVE: The objectives of this study are to (1) compare the BSE surveillance systems of Japan and the United States (US), and to (2) validate the US enhanced BSE Surveillance program. METHODS: This study compares the BSE surveillance systems in Japan and the US, specifically focusing on the procedures of initial test, diagnosis and confirmation. The study further examines the validity of statistical conclusions made in the US enhanced surveillance program based on the data collected from the BSE inspection performed by the Ministry of Health, Labor and Welfare of Japan (MHLW) and the Ministry of Agriculture, Forestry and Fisheries of Japan (MAFF) between October 18,2001 and July 31, 2004. The inspection targeted all slaughtered healthy and high risk cattle. RESULTS: The US enhanced surveillance program assumes no BSE occurrence in the normal adult cattle population and thus its inspection focuses only on high risk cattle. The BSE inspection performed in Japan, however, revealed that 0.00022% of the normal adult cattle were BSE-infected using the US criteria. Assuming that the same ratio of cattle was BSE-infected in the US, the Japan finding indicates that approximately 30% of the US slaughtered normal cattle population aged 30 months and over needs to be tested to satisfy the statistical condition used by the US (i.e., 99% confidence level). On the other hand, in order for Japan to perform the surveillance with a 99% confidence level (the statistical condition used by US), Japan needs inspect: (1) 60,539 high risk cattle (i.e., 60% of 100,583 high risk cattle); (2) 78% of normal adult cattle aged 30 months and over (1,088,589/1,387,522) and (3) 90% of normal cattle aged 30 months or less (1,845,138/2,050,154). CONCLUSION: The US enhanced surveillance program launched in July 2004 is based on the premise that no BSE occurs in normal adult cattle population. In Japan, however, BSE cases satisfying the US criteria have been found among the normal adult cattle. This fact suggests that the US needs to consider inspections targeting the normal adult cattle. This fact suggests that the US needs to consider inspections targeting the normal adult cattle in the future. At the same time, for more efficient surveillance, Japan may need to consider BSE inspections targeting the high risk cattle population with a higher confidence level and normal adult cattle with a lower confidence level.

Modeling patient flows using a queuing network with blocking.

The downsizing and closing of state mental health institutions in Philadelphia in the 1990's led to the development of a continuum care network of residential-based services. Although the diversity of care settings increased, congestion in facilities caused many patients to unnecessarily spend extra days in intensive facilities. This study applies a queuing network system with blocking to analyze such congestion processes. "Blocking" denotes situations where patients are turned away from accommodations to which they are referred, and are thus forced to remain in their present facilities until space becomes available. Both mathematical and simulation results are presented and compared. Although queuing models have been used in numerous healthcare studies, the inclusion of blocking is still rare. We found that, in Philadelphia, the shortage of a particular type of facilities may have created "upstream blocking". Thus removal of such facility-specific bottlenecks may be the most efficient way to reduce congestion in the system as a whole.