Financial Performance of Accountable Care Organizations: A 5-Year National Empirical Analysis.

GOALS: Of 513 accountable care organizations (ACOs) participating in the Medicare Shared Savings Program (MSSP) in 2020, 67% generated a positive shared savings of approximately $2.3 billion. This research aimed to examine their financial performance trends and drivers over time. METHODS: The unit of analysis was the ACO in each year of the study period from 2016 to 2020. The dependent variable was the ACOs' total shared savings earned annually per beneficiary. The independent variables included ACO age, risk model, clinician staffing type, and provider type (hybrid, hospital-led, or physician-led). Covariates were the average risk score among beneficiaries, payer type, and calendar year. The Centers for Medicare & Medicaid Services (CMS) public use files (PUFs) and a commercial healthcare data aggregator were the data sources. RESULTS: ACOs' earned shared savings grew annually by 35%, while the proportions of ACOs with positive shared savings grew by 21%. For 1-year increase in ACO age, an additional $0.57 of shared savings per beneficiary was observed. ACOs with two-sided risk contracting were associated with an average marginal increase of $109 in shared savings per beneficiary compared to ACOs with one-sided risk contracting. Primary care physicians were associated with the greatest increase in earned shared savings per beneficiary. In contrast, nurse practitioners/physician assistants/clinical nurse specialists were associated with a reduction in earned shared savings. Under a one-sided risk model, hospital-led ACOs were associated with $18 higher average shared savings earning per beneficiary compared to hybrid ACOs, while physician-led ACOs were associated with lower average saved shared earnings per beneficiary at -$2 compared to hybrid ACOs. Provider-type results were not statistically significant at the 5% nominal level. No statistically significant differences were observed between provider types under a two-sided risk model. PRACTICAL APPLICATIONS: For all ACO provider types, building broader primary care provider networks was correlated with positive financial results. Future research should examine whether ACOs are conducting specific preventive screenings for cancer or monitoring conditions such as diabetes, hypertension, heart disease, obesity, mental disorders, and joint disorders. Such studies may answer health policy and strategy questions about the effects of incentives for improved ACO performance in serving a healthier population.

Comparison of trace element mobility from MSWI ash before and after plasma vitrification.

A common perception of plasma arc treatment systems for municipal solid waste incineration ash is that the resulting vitrified slag is inert from an environmental perspective. Research was conducted to examine this hypothesis and to assess whether reduced pollutant release results from pollutant depletion during the process of the ash with plasma, or encapsulation in the glassy vitrified matrix. The concentrations of four discrete municipal solid waste incineration ash samples before and after plasma arc vitrification in a bench-scale unit were compared. Slag and untreated ash samples were leached using several standardized approaches and mobility among the four metals of interest (e.g. As, Cd, Pb and Sb) varied across samples, but was generally high (as high as 100% for Cd). Comparison across methods did not indicate substantial encapsulation in the vitrified slag, which suggests that reduced pollutant release from plasma arc vitrified slag is due to pollutant depletion by volatilization, not encapsulation. This has significant implications for the management of air pollution control residues from waste-to-energy facilities using plasma arc vitrification.

Fiber Reinforced Compressed Earth Blocks: Evaluating Flexural Strength Characteristics Using Short Flexural Beams.

There are ongoing research efforts directed at addressing strength limitations of compressed earth blocks (CEB) that inhibit their deployment for structural applications, particularly in areas where masonry systems are regularly subjected to lateral loads from high winds. In this paper, the authors focus specifically on the extent to which polypropylene (PP) fibers can be used to enhance the flexural performance of CEB. Cementitious matrices used for CEB production exhibit low tensile and flexural strength (brittle) properties. This work investigates plain (unreinforced) and fiber-reinforced specimens (short flexural beams) with fiber mass content of 0.2, 0.4, 0.6, 0.8, and 1.0% and ordinary Portland cement (OPC) content of 8%. The influence of the inclusion of fiber was based on tests conducted using the Standard Test Method for Flexural Performance of Fiber-Reinforced Concrete (ASTM C1609). Material properties that were quantified included first-peak strength, peak strength, equivalent flexural strength, residual strength, and flexural toughness. There was an observed improvement in the performance of the soil-fiber matrixes based on these results of these tests. It was also observed that when the fiber content exceeded 0.6% and above, specimens exhibited a deflection- hardening behavior; an indication of improvement in ductility. An equivalent flexural strength predictive model is proposed.

Characterisation and management of concrete grinding residuals.

Concrete grinding residue is the waste product resulting from the grinding, cutting, and resurfacing of concrete pavement. Potential beneficial applications for concrete grinding residue include use as a soil amendment and as a construction material, including as an additive to Portland cement concrete. Concrete grinding residue exhibits a high pH, and though not hazardous, it is sufficiently elevated that precautions need to be taken around aquatic ecosystems. Best management practices and state regulations focus on reducing the impact on such aquatic environment. Heavy metals are present in concrete grinding residue, but concentrations are of the same magnitude as typically recycled concrete residuals. The chemical composition of concrete grinding residue makes it a useful product for some soil amendment purposes at appropriate land application rates. The presence of unreacted concrete in concrete grinding residue was examined for potential use as partial replacement of cement in new concrete. Testing of Florida concrete grinding residue revealed no dramatic reactivity or improvement in mortar strength.

Construction material properties of slag from the high temperature arc gasification of municipal solid waste.

Slag from the high temperature arc gasification (HTAG) of municipal solid waste (MSW) was tested to evaluate its material properties with respect to use as a construction aggregate. These data were compared to previously compiled values for waste to energy bottom ash, the most commonly produced and beneficially used thermal treatment residue. The slag was tested using gradations representative of a base course and a course aggregate. Los Angeles (LA) abrasion testing demonstrated that the HTAG slag had a high resistance to fracture with a measured LA loss of 24%. Soundness testing indicated a low potential for reactivity and good weathering resistance with a mean soundness loss of 3.14%. The modified Proctor compaction testing found the slag to possess a maximum dry density (24.04kN/m(3)) greater than conventionally used aggregates and WTE BA. The LBR tests demonstrated a substantial bearing capacity (>200). Mineralogical analysis of the HTAG suggested the potential for self cementing character which supports the elevated LBR results. Preliminary material characterization of the HTAG slag establishes potential for beneficial use; larger and longer term studies focusing on the material's possibility for swelling and performance at the field scale level are needed.

Use of leaching tests to quantify trace element release from waste to energy bottom ash amended pavements.

A series of roadway tests strips were paved on-site at a landfill in Florida, U.S. Waste to energy (WTE) bottom ash was used as a partial course aggregate replacement in a hot mix asphalt (HMA) and a Portland cement concrete (PCC) pavement, along with control HMA and PCC sections. This allowed for a comparison of the relative degree of leaching between both materials (HMA and PCC) as well as between the ash-amended and control pavements. Batch and monolithic tank leaching tests were conducted on the pavements. Testing of the PCC samples demonstrated that Mo and Al were elevated above regulatory thresholds for both the control and ash amended samples. Further leach testing demonstrated that the release of Mo was likely from the PCC and not a result of the inclusion of the BA into pavement. Batch leach testing of ash-amended HMA samples revealed Sb as a constituent of potential concern. The results of the monolith leaching test displayed leaching of Sb within the same order of magnitude as the regulatory threshold. Calculation of the leachability index (LI) for Sb found that it would have limited mobility when incorporated in the HMA matrix.