Characterizing the Traveling Oncology Workforce and Its Influence on Patient Travel Burden: A Claims-Based Approach.

PURPOSE: Oncology outreach is a common strategy for extending cancer care to rural patients. However, a nationwide characterization of the traveling workforce that enables this outreach is lacking, and the extent to which outreach reduces travel burden for rural patients is unknown. METHODS: This cross-sectional study analyzed a rural (nonurban) subset of a 100% fee-for-service sample of 355,139 Medicare beneficiaries with incident breast, colorectal, and lung cancers. Surgical, medical, and radiation oncologists were linked to patients using Part B claims, and traveling oncologists were identified by observing hospital service area (HSA) transition patterns. We defined oncology outreach as the provision of cancer care by a traveling oncologist outside of their primary HSA. We used hierarchical gamma regression models to examine the separate associations between patient receipt of oncology outreach and one-way patient travel times to chemotherapy, radiotherapy, and surgery. RESULTS: On average, 9,935 of 39,960 oncologists conducted annual outreach, where 57.8% traveled with low frequency (0-1 outreach visits/mo), 21.1% with medium frequency (1-3 outreach visits/mo), and 21.1% with high frequency (>3 outreach visits/mo). Oncologists provided surgery, radiotherapy, and chemotherapy to 51,715, 27,120, and 5,874 rural beneficiaries, respectively, of whom 2.5%, 6.9%, and 3.6% received oncology outreach. Rural patients who received oncology outreach traveled 16% (95% CI, 11 to 21) and 11% (95% CI, 9 to 13) less minutes to chemotherapy and radiotherapy than those who did not receive oncology outreach, corresponding to expected one-way savings of 15.9 (95% CI, 15.5 to 16.4) and 11.9 (95% CI, 11.7 to 12.2) minutes, respectively. CONCLUSION: Our study introduces a novel claims-based approach for tracking the nationwide traveling oncology workforce and supports oncology outreach as an effective means for improving rural access to cancer care.

Broadband Data Forensics: Spatiotemporal Variations of the Download/Upload Speed Metric Commonly Used to Evaluate Potential Telehealth Accessibility.

Introduction: The complicated task of evaluating potential telehealth access begins with the metrics and supporting datasets that seek toevaluate the presence and durability of broadband connections in a community. Broadband download/upload speeds are one of the popular metrics used to measure potential telehealth access, which is critical to health equity. An understanding of the limitations of these measures is important for drawing conclusions about the reality of the digital divide in telehealth access. The objective of this study was to assess spatiotemporal variations in broadband download/upload speeds. Method: We analyzed a sample of data from the Speedtest Intelligence Portal provided through the Ookla for Good initiative. Results: We found that variation is inherent across the states of Vermont, New Hampshire, Louisiana, and Utah. Conclusions: The variation suggests that when single measures of download/upload speeds are used to evaluate telehealth accessibility they may be masking the true magnitude of the digital divide.

Refining 2SVCA Method for Measuring Telehealth Accessibility of Primary Care Physicians in Baton Rouge, Louisiana.

Equity in health care delivery is a longstanding concern of public health policy. Telehealth is considered an important way to level the playing field by broadening health services access and improving quality of care and health outcomes. This study refines the recently developed "2-Step Virtual Catchment Area (2SVCA) method" to assess the telehealth accessibility of primary care in the Baton Rouge Metropolitan Statistical Area, Louisiana. The result is compared to that of spatial accessibility via physical visits to care providers based on the popular 2-Step Floating Catchment Area (2SFCA) method. The study shows that both spatial and telehealth accessibilities decline from urban to low-density and then rural areas. Moreover, disproportionally higher percentages of African Americans are in areas with higher spatial accessibility scores; but such an advantage is not realized in telehealth accessibility. In the study area, absence of broadband availability is mainly a rural problem and leads to a lower average telehealth accessibility than physical accessibility in rural areas. On the other side, lack of broadband affordability is a challenge across the rural-urban continuum and is disproportionally associated with high concentrations of disadvantaged population groups such as households under the poverty level and Blacks.

Disparities in spatial accessibility of primary care in Louisiana: From physical to virtual accessibility.

Telehealth has been widely employed and has transformed how healthcare is delivered in the United States as a result of COVID-19 pandemic. While telehealth is utilized and encouraged to reduce the cost and travel burden for access to healthcare, there are debates on whether telehealth can promote equity in healthcare services by narrowing the gap among diverse groups. Using the Two-Step Floating Catchment Area (2SFCA) and Two-Step Virtual Catchment Area (2SVCA) methods, this study compares the disparities of physical and virtual access to primary care physicians (PCPs) in Louisiana. Both physical and virtual access to PCPs exhibit similar spatial patterns with higher scores concentrated in urban areas, followed by low-density and rural areas. However, the two accessibility measures diverge where broadband availability and affordability come to play an important role. Residents in rural areas experience additive disadvantage of even more limited telehealth accessibility than physical accessibility due to lack of broadband service provision. Areas with greater Black population proportions tend to have better physical accessibility, but such an advantage is eradicated for telehealth accessibility because of lower broadband subscription rates in these neighborhoods. Both physical and virtual accessibility scores decline in neighborhoods with higher Area Deprivation Index (ADI) values, and the disparity is further widened for in virtual accessibility compared to than physical accessibility. The study also examines how factors such as urbanicity, Black population proportion, and ADI interact in their effects on disparities of the two accessibility measures.

Numerical and Experimental Study on Flame Dynamics of the Premixed Methane-Air Mixture at Different Ignition Positions in a Two-Side 45° Branch Tube.

The combustion characteristics of premixed methane-air flames in a half-open tube with a two-sided 45° branch structure at different ignition positions were investigated by experiments and large eddy simulations. The numerical results were compared with the experimental results to verify the correctness of the model. The results show that the simulation results are highly consistent with the experiment. This study provides a basic understanding of the effects of the branch tube structure and the ignition position on flame dynamics. When the flame propagates to the branch interface, it forms a symmetrical vortex structure at the branch tube with the opposite rotation direction. When the ignition position is at IP0 and IP900, the maximum overpressures obtained in the experiment are 10.1 and 10.7 kPa, respectively, and 9.2 and 10.4 kPa in the simulation, respectively. At IP0, the Karlovitz number indicating the interaction intensity between the flame surface and the turbulence during flame propagation is a maximum of 9.2 and a minimum of 0.04. The premixed flame has a folded small flame, a corrugated small flame, and a thin reaction zone.

The interaction of rurality and rare cancers for travel time to cancer care.

PURPOSE: Geographic access to cancer care is known to significantly impact utilization and outcomes. Longer travel times have negative impacts for patients requiring highly specialized care, such as for rare cancers, and for those in rural areas. Scant population-based research informs geographic access to care for rare cancers and whether rurality impacts that access. METHODS: Using Medicare data (2014-2015), we identified prevalent cancers and cancer-directed surgeries, chemotherapy, and radiation. We classified cancers as rare (incidence <6/100,000/year) or common (incidence ≥6/100,000/year) using previously published thresholds and categorized rurality from ZIP code of beneficiary residence. We estimated travel time between beneficiaries and providers for each service based on ZIP code. Descriptive statistics summarized travel time by rare versus common cancers, service type, and rurality. FINDINGS: We included 1,169,761 Medicare beneficiaries (21.9% in nonmetropolitan areas), 87,399; 7.5% had rare cancers, with 9,133,003 cancer-directed services. Travel times for cancer services ranged from approximately 29 minutes (25th percentile) to 68 minutes (75th percentile). Travel times were similar for rare and common cancers overall (median: 45 vs 43 minutes) but differed by service type; 13.4% of surgeries were >2 hours away for rare cancers, compared to 8.3% for common cancers. Increasing rurality disproportionately increased travel time to surgical care for rare compared to common cancers. CONCLUSIONS: Travel times to cancer services are longest for surgery, especially among rural residents, yet not markedly longer overall between rare versus common cancers. Understanding geographic access to cancer care for patients with rare cancers is important to delivering specialized care.

Multiscale analysis of cancer service areas in the United States.

The purpose of delineating Cancer Service Areas (CSAs) is to define a reliable unit of analysis, more meaningful than geopolitical units such as states and counties, for examining geographic variations of the cancer care markets using geographic information systems (GIS). This study aims to provide a multiscale analysis of the U.S. cancer care markets based on the 2014-2015 Medicare claims of cancer-directed surgery, chemotherapy, and radiation. The CSAs are delineated by a scale-flexible network community detection algorithm automated in GIS so that the patient flows are maximized within CSAs and minimized between them. The multiscale CSAs include those comparable in size to those 4 census regions, 9 divisions, 50 states, and also 39 global optimal CSAs that generates the highest modularity value. The CSAs are more effective in capturing the U.S. cancer care markets because of its higher localization index, lower cross-border utilizations, and shorter travel time. The first two comparisons reveal that only a few regions or divisions are representative of the underlying cancer care markets. The last two comparisons find that among the 39 CSAs, 54% CSAs comprise multiple states anchored by cities near inner state borders, 28% are single-state CSAs, and 18% are sub-state CSAs. Their (in)consistencies across state borders or within each state shed new light on where the intervention of cancer care delivery or the adjustment of cancer care costs are needed to meet the challenges in the U.S. cancer care system. The findings could guide stakeholders to target public health policies for more effective coordination of cancer care in improving outcomes and reducing unnecessary costs.

GIS-Automated Delineation of Hospital Service Areas in Florida: From Dartmouth Method to Network Community Detection Methods.

Since the Dartmouth hospital service areas (HSAs) were proposed three decades ago, there has been a large body of work using the unit in examining the geographic variation in health care in the U.S. for evaluating health care system performance and informing health policy. However, many studies question the replicability and reliability of the Dartmouth HSAs in meeting the challenges of ever-changing and a diverse set of health care services. This research develops a reproducible, automated, and efficient GIS tool to implement Dartmouth method for defining HSAs. Moreover, the research adapts two popular network community detection methods to account for spatial constraints for defining HSAs that are scale flexible and optimize an important property such as maximum service flows within HSAs. A case study based on the state inpatient database in Florida from the Healthcare Cost and Utilization Project is used to evaluate the efficiency and effectiveness of the methods. The study represents a major step toward developing HSA delineation methods that are computationally efficient, adaptable for various scales (from a local region to as large as a national market), and automated without a steep learning curve for public health professionals.

Flame Propagation Characteristics of Syngas-Air in the Hele-Shaw Duct with Different Equivalence Ratios and Ignition Positions.

In this paper, the effects of different ignition positions and equivalence ratios on the explosion characteristics of syngas in a half-open Hele-Shaw duct were investigated. The ignition points are set at distances of 0 and 500 mm from the closed end. Moreover, the research range of equivalence ratio is 0.8-1.2. The experimental results indicate that different ignition positions and equivalence ratios influence the flame front structure and the dynamic characteristics of flame propagation. When the ignition position is at the closed end, the flame front undergoes several typical propagation stages before eventually reaching the open end of the duct. The time required by the flame to reach the open end decreases as the equivalence ratio increases. Meanwhile, when the ignition is in the middle of the duct, the flame simultaneously spreads to the open and closed ends. The time required to reach both sides decreases with the increase in the equivalence ratio. The flame front structure and pressure are primarily affected by the ignition position and the equivalence ratio. At the same ignition position, flame propagation velocity and maximum overpressure increase with the equivalence ratio. The pressure oscillation becomes more intense when the ignition position is close to the open end. At IP500, when the equivalence ratio is 0.8, multiple finger-shaped flame fronts emerge, accompanied by high-frequency flame oscillations. This study can provide guidance for the study of the flame propagation characteristics of syngas in millimeter-scale burners.

Rural-Urban Differences in Breast Cancer Surgical Delays in Medicare Beneficiaries.

BACKGROUND: Delays between breast cancer diagnosis and surgery are associated with worsened survival. Delays are more common in urban-residing patients, although factors specific to surgical delays among rural and urban patients are not well understood. METHODS: We used a 100% sample of fee-for-service Medicare claims during 2007-2014 to identify 238,491 women diagnosed with early-stage breast cancer undergoing initial surgery and assessed whether they experienced biopsy-to-surgery intervals > 90 days. We employed multilevel regression to identify associations between delays and patient, regional, and surgeon characteristics, both in combined analyses and stratified by rurality of patient residence. RESULTS: Delays were more prevalent among urban patients (2.5%) than rural patients (1.9%). Rural patients with medium- or high-volume surgeons had lower odds of delay than patients with low-volume surgeons (odds ratio [OR] = 0.71, 95% confidence interval [CI] = 0.58-0.88; OR = 0.74, 95% CI = 0.61-0.90). Rural patients whose surgeon operated at ≥ 3 hospitals were more likely to experience delays (OR = 1.29, 95% CI = 1.01-1.64, Ref: 1 hospital). Patient driving times ≥ 1 h were associated with delays among urban patients only. Age, black race, Hispanic ethnicity, multimorbidity, and academic/specialty hospital status were associated with delays. CONCLUSIONS: Sociodemographic, geographic, surgeon, and facility factors have distinct associations with > 90-day delays to initial breast cancer surgery. Interventions to improve timeliness of breast cancer surgery may have disparate impacts on vulnerable populations by rural-urban status.

Kinetic Analysis of Laminar Combustion Characteristics of a H2/Cl2 Mixture at CO2/N2 Dilution.

Garbage and biomass contain more chlorine, which reacts with H2 to form HCl gas during combustion or gasification, resulting in corrosion of metal walls. In this paper, based on the chlorine mechanism in Ansys Chemkin-Pro, the laminar combustion characteristics of H2/Cl2 are simulated with different diluents CO2/N2 under an initial temperature of 298 K, equivalence ratio range of 0.6-1.4, and initial pressure of 0.1-0.5 MPa. The results show that the laminar burning velocity of H2/Cl2 decreases significantly with the increase of dilution gas ratio, and the effect of diluent CO2 is more significant than that of N2. Due to the dilution effect, the fuel and oxidation components are reduced. Through sensitivity analysis, reaction R2: Cl + H2 = HCl + H is the main reaction of HCl formation. On improving the initial pressure, the laminar burning velocity is slightly lowered, and the thermal diffusivity of the fuel mixture increases with the increase of the initial pressure. According to the sensitivity analysis of the velocity, reactions R2, R9, and R10 are the main reactions that affect the laminar burning velocity, and the product HCl will be generated with a delay with the increase of the initial pressure.

Delineation of Cancer Service Areas Anchored by Major Cancer Centers in the United States.

Defining a reliable geographic unit pertaining to cancer care is essential in its assessment, planning, and management. This study aims to delineate and characterize the cancer service areas (CSA) accounting for the presence of major cancer centers in the United States. We used the Medicare enrollment and claims from January 1, 2014 to September 30, 2015 to build a spatial network from patients with cancer to cancer care facilities that provided inpatient and outpatient care of cancer-directed surgery, chemotherapy, and radiation. After excluding those without clinical care or outside of the United States, we identified 94 NCI-designated and other academic cancer centers from the members of the Association of American Cancer Institutes. By explicitly incorporating existing specialized cancer referral centers, we refined the spatially constrained Leiden method that accounted for spatial adjacency and other constraints to delineate coherent CSAs within which the service volumes were maximal but minimal between them. The derived 110 CSAs had a high mean localization index (LI; 0.83) with a narrow variability (SD = 0.10). The variation of LI across the CSAs was positively associated with population, median household income, and area size, and negatively with travel time. Averagely, patients traveled less and were more likely to receive cancer care within the CSAs anchored by cancer centers than their counterparts without cancer centers. We concluded that CSAs are effective in capturing the local cancer care markets in the United States. They can be used as reliable units for studying cancer care and informing more evidence-based policy. Significance: Using the most refined network community detection method, we can delineate CSAs in a more robust, systematic, and empirical manner that incorporates existing specialized cancer referral centers. The CSAs can be used as a reliable unit for studying cancer care and informing more evidence-based policy in the United States. The cross-walk tabulation of ZIP code areas, CSAs, and related programs for CSAs delineation are disseminated for public access.

The uneven reaction to combat the COVID-19 pandemic: Geovisualizing of fever clinics in mainland China.

The COVID-19 pandemic has exerted unprecedented impacts on the world. Since its onset, China has established a network of fever clinics as an effective strategy to aggressively isolate and screen possible patients with COVID-19 symptoms. This study presents two fever clinic maps that visualize the uneven responses to the COVID-19 pandemic at the city level in mainland China. The maps highlight more resources in the southwest, northwest, east, and south China, and paucity in the far west parts of southwest and northwest China and in the north and northeast China.

Network Optimization Approach to Delineating Health Care Service Areas: Spatially Constrained Louvain and Leiden Algorithms.

Constructing service areas is an important task for evaluating geographic variation of health care markets. This study uses cancer care as an example to illustrate the methodology, with the nine-state Northeast Region of the U.S. as the study area. Two recent algorithms of network community detection are implemented to account for additional constraints such as spatial connectivity and threshold region size. The refined methods are termed "spatially-constrained Louvain (ScLouvain)" and "spatially-constrained Leiden (ScLeiden)" algorithms, corresponding to their predecessors Louvain and Leiden algorithms, respectively. Both are network optimization methods that maximize flows within delineated communities while minimizing inter-community flows. The service areas derived by the methods, termed "Cancer Service Areas (CSAs)", are more favorable than the commonly used comparable unit, Hospital Referral Regions (HRRs) for evaluating cancer-specific variation in care. Between the two, the ScLeiden performs better than ScLouvain in modularity, localization index and computational efficiency, and thus is recommended as an effective and efficient approach for defining functional regions.

Incorporating broadband durability in measuring geographic access to health care in the era of telehealth: A case example of the 2-step virtual catchment area (2SVCA) Method.

The COVID-19 (coronavirus disease 2019) pandemic has expanded telehealth utilization in unprecedented ways and has important implications for measuring geographic access to healthcare services. Established measures of geographic access to care have focused on the spatial impedance of patients in seeking health care that pertains to specific transportation modes and do not account for the underlying broadband network that supports telemedicine and e-health. To be able to measure the impact of telehealth on healthcare access, we created a pilot augmentation of existing methods to incorporate measures of broadband accessibility to measure geographic access to telehealth. A reliable measure of telehealth accessibility is important to enable policy analysts to assess whether the increasing prevalence of telehealth may help alleviate the disparities in healthcare access in rural areas and for disadvantaged populations, or exacerbate the existing gaps as they experience "double burdens."

Spatial Behavior of Cancer Care Utilization in Distance Decay in the Northeast Region of the U.S.

PURPOSE: Spatial behavior of patients in utilizing health care reflects their travel burden or mobility, accessibility for medical service, and subsequently outcomes from treatment. This paper derives the best-fitting distance decay function to capture the spatial behaviors of cancer patients in the Northeast region of the U.S., and examines and explains the spatial variability of such behaviors across sub-regions. PRINCIPAL RESULTS: (1) 46.8%, 85.5%, and 99.6% of cancer care received was within a driving time of 30, 60 and 180 minutes, respectively. (2) The exponential distance decay function is the best in capturing the travel behavior of cancer patients in the region and across most sub-regions. (3) The friction coefficient in the distance decay function is negatively correlated with the mean travel time. (4) The best-fitting function forms are associated with network structures. (5) The variation of the friction coefficient across sub-regions is related to factors such as urbanicity, economic development level, and market competition intensity. MAJOR CONCLUSIONS: The distance decay function offers an analytic metric to capture a full spectrum of travel behavior, and thus a more comprehensive measure than average travel time. Examining the geographic variation of travel behavior needs a reliable analysis unit such as organically defined "cancer service areas", which capture relevant health care market structure and thus are more meaningful than commonly-used geopolitical or census area units.

Perceived urban green and residents' health in Beijing.

Green space serves urban residents in various functions including promoting health, but the roles of different types of green space are unclear. A survey titled "Healthy Neighborhood" was conducted in Beijing from May to July 2019 to examine and compare the associations between three types of perceived green space (park green, public-square green and utility green) and three aspects of residents' health (physical health, mental health and social health). Results from the multilevel modeling (MLM) analysis show that the perceived park green has a positive correlation with mental health, and all three types of perceived green space correlate with social health positively. No significant correlation of any type of green space is detected on participants' physical health, nor any relation of public-square green or utility green to their mental health. Overall the role of urban green space is stronger on social health than physical and mental health. The findings support the complementary roles of different types of green space, and suggest that expansion in utility greens could be as effective as investing in more costly park and public-square greens, especially in their benefit in promoting social health.

From 2SFCA to i2SFCA: integration, derivation and validation.

Uneven distributions of population and service providers lead to geographic disparity in access for residents and varying workload for staff in facilities. The former can be captured by spatial accessibility in the traditional two-step floating catchment area (2SFCA) method; and the latter can be measured by potential crowdedness in the newly developed inverted 2SFCA (or i2SFCA) method. Residents-based accessibility and facility crowdedness are two sides of the same coin in examining the geographic variability of resource allocation. This short research note derives the formulations of both methods to solidify their theoretical foundation, and uses a case study to validate both. By doing so, the 2SFCA and i2SFCA are fully integrated into one conceptual framework, derived with extensions to the Huff model, and validated by empirical data.

Numerical Simulation of the Effect of CH4/CO Concentration on Combustion Characteristics of Low Calorific Value Syngas.

The composition of low calorific value synthesis gas varies greatly depending on the raw material and processing technology, which makes the combustion extremely complicated. The three mechanisms of the GRI-Mech 3.0, Li-Model, and FFCM-Mech are used to numerically simulate CH4/CO/H2/N2 air premixed combustion by using ANSYS CHEMKIN-PRO. The numerical simulation is the calculation of laminar flame velocity and adiabatic flame temperature at an initial temperature of 298 K, an equivalence ratio of 0.6-1.4, and an initial pressure of 0.1-0.5 MPa, discussing through thermodynamics and chemical kinetics. The formation of NO X , H, and OH radicals by fuel composition was analyzed. The result shows that the concentrations of H, O, and OH radicals have a positive effect on laminar flame velocity. The combustion reaction of H2 is higher than that of CH4 and CO; with the increase of N2 content, the priority is higher. The thermal diffusivity of flame under different equivalence ratios is affected by inert gas, which affects adiabatic combustion temperature and laminar combustion velocity. In thermal kinetics and chemical kinetics, CH4 has more influence on combustion temperature than CO, while laminar flame velocity is relatively low. Under the change of initial pressure, the laminar combustion flux increases to the initial pressure and the laminar combustion velocity decreases to the increase in pressure. Reactions H + O2 = O + OH, HO2 + H = 2OH, and CH3 + HO2 = OH + CH3O are mainly due to change in the concentration of O, H, and OH radicals.

Experimental Study on the Explosion Characteristics of CH4/O2/N2 Mixtures with Different Oxygen Enrichment Coefficients and Ignition Positions.

In this paper, the flame propagation characteristics and overpressure oscillation characteristics of CH4 explosion were studied under different ignition positions (IPs) and oxygen enrichment conditions in a half-open tube. The distances between the IP and the closed end of the tube are 0, 250, 500, and 750 mm. The oxygen enrichment coefficient (φ) values used in the experiment are 0.21, 0.3, and 0.4. The experimental results show that the IP and oxygen enrichment coefficient have an important influence on the flame structure and overpressure oscillation. Only when the oxygen enrichment coefficient φ = 0.21, a tulip flame will be formed. The IP close to the outlet can make the air participate in the combustion more quickly. With the increase of the oxygen enrichment coefficient, the combustion-induced rapid phase transition phenomenon is more likely to occur, and the maximum overpressure value and the overpressure rise rate of flame will increase. It is worth noting that after increasing the oxygen enrichment coefficient, the IP has less influence than the oxygen enrichment coefficient on the overpressure rise rate.