3,967 research outputs found

    Integrating, Customizing, and Extending Environments with a Message-Based Architecture

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    Message-based architectures have typically been used for integrating an engineer‘s set of tools as in FIELD and SoftBench. This paper presents our experience using a message-based architecture to integrate complex, multi-user environments. Where this style of control integration has been effective for encapsulating independent tools within an environment, we show that these techniques are also useful for integrating environments themselves. Our experience comes from our integration of two types of process-centered software development environments: a groupware application that implements a Fagan-style code inspection process and a software development process environment where code inspection is a single step in the overall process. We use a message-based mechanism to federate the two process engines such that the two process formalisms complement rather than compete with each other. Moreover, we see that the two process engines can provide some synergy when used in a single, integrated software process environment, Specifically, the integrated environment uses the process modeling and enactment services of one process engine to customize and extend the code inspection process implemented in a different process engine. The customization and extension of the original collaborative application was accomplished without modifying the application. This was possible because the integration mechanism was designed for multi-user, distributed evironments and encouraged the use of an environment‘s services by other environments. The results of our study indicate that the message-based architecture originally conceived for tool-oriented control integration is equally well-suited for environment integration

    Zirconium and titanium complexes supported by tridentate LX2 ligands having two phenolates linked to furan, thiophene, and pyridine donors: precatalysts for propylene polymerization and oligomerization

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    Zirconium and titanium complexes with tridentate bis(phenolate)-donor (donor = pyridine, furan and thiophene) ligands have been prepared and investigated for applications in propylene polymerization. The ligand framework has two X-type phenolates connected to the flat heterocyclic L-type donor at the 2,6- or 2.5- positions via direct ring-ring (sp^2-sp^2)linkages. The zirconium and titanium dibenzyl complexes have been prepared by treatment of the neutral bis(phenol)-donor ligands with M(CH_2Ph)_4 (M = Ti, Zr) with loss of 2 equiv of toluene. Titanium complexes with bis(phenolate)pyridine and -furan ligands and zirconium complexes with bis(phenolate)pyridine and -thiophene ligands have been characterized by single-crystal X-ray diffraction. The solid-state structures of the bis(benzyl)titanium complexes are roughly C_2 symmetric, while the zirconium derivatives display C_s and C^1 symmetry. The bis(phenolate)pyridine titanium complexes are structurally affected by the size of the substituents substituents (CMe_3 or CEt_3) ortho to the oxygens, the larger group leading to a larger C_2 distortion. Both titanium and zirconium dibenzyl complexes were found to be catalyst precursors for the polymerization of propylene upon activation with methylaluminoxane (MAO). The activities observed for the zirconium complexes are particularly notable, exceeding 10^6 g polypropylene/mol Zr center dot h in some cases. The bis(phenolate)pyridine titanium analogues are about 10^3 times less active, but generate polymers of higher molecular weight. When activated with MAO, the titanium bis(phenolate)furan and bis(phenolate)thiophene systems were found to promote propylene oligomerization

    Spinning Tubes: An Authentic Research Experience in a Three-hour Laboratory

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    We discuss a three-hour laboratory that is a microcosm of physics research, starting with the discovery of an intriguing phenomenon, and including participation in “research conferences” and the interplay of theory and experiment. Students are given a small segment of PVC pipe marked at opposite ends with different symbols and asked to observe what happens when the pipe is placed on a horizontal surface and one end is pushed downward by a finger to initiate a rotation. Most students immediately recognize that the symbol at one end is visible while the other is not, and set about trying to understand why. Students initially work in pairs and are provided with opportunities to request equipment from a “granting agency” and conferences and collaborations are encouraged. Students are quickly caught up in their search for explanations, usually culminating in a full-class effort with significant contributions coming from all students

    Association of physician group practice participation in bundled payments with patient selection, costs, and outcomes for joint replacement

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    IMPORTANCE: Medicare\u27s Bundled Payments for Care Improvement (BPCI) program, which ran from 2013 to 2018, was an important experiment in physician-focused alternative payment models. However, little is known about whether the program was associated with better quality or outcomes or lower costs. OBJECTIVE: To determine whether participation in BPCI among physician group practices was associated with advantageous or deleterious changes in costs or patient outcomes. DESIGN SETTING AND PARTICIPANTS: This cross-sectional study used 2013 to 2017 Medicare files and difference-in-differences (DID) models to compare the change over time in Medicare payments, patient selection, and clinical outcomes between 91 orthopedic groups in BPCI Model 2 and 169 propensity-matched controls for patients undergoing joint replacement. Analyses were performed between December 2019 and February 2021. EXPOSURES: Voluntary participation in BPCI. MAIN OUTCOMES AND MEASURES: The primary outcome was 90-day Medicare payments; secondary outcomes were patient selection (volume, comorbidities) and clinical outcomes (30-day and 90-day emergency department visits, readmissions, mortality, and healthy days at home). RESULTS: There were 74 343 patient episodes in the baseline period and 102 790 during the intervention in BPCI practices, and 88 147 patient episodes in the baseline period and 120 253 during the intervention in control practices; 291 214 of 461 598 (63.1%) patients were women, and 419 619 (90.9%) were White. At baseline, mean episode payments among BPCI-participating practices were 18257,whichdecreasedto18 257, which decreased to 15 320 during the intervention, while control practices decreased from 17927to17 927 to 16 170 (DID, -1180;951180; 95% CI, -1565 to -$795; CONCLUSIONS AND RELEVANCE: Group practice participation in BPCI for joint replacement was associated with reduced Medicare payments and improvements in clinical outcomes

    Year 1 of the Bundled Payments for Care Improvement-Advanced model

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    BACKGROUND: The Center for Medicare and Medicaid Innovation launched the Medicare Bundled Payments for Care Improvement-Advanced (BPCI-A) program for hospitals in October 2018. Information is needed about the effects of the program on health care utilization and Medicare payments. METHODS: We conducted a modified segmented regression analysis using Medicare claims and including patients with discharge dates from January 2017 through September 2019 to assess differences between BPCI-A participants and two control groups: hospitals that never joined the BPCI-A program (nonjoining hospitals) and hospitals that joined the BPCI-A program in January 2020, after the conclusion of the intervention period (late-joining hospitals). The primary outcomes were the differences in changes in quarterly trends in 90-day per-episode Medicare payments and the percentage of patients with readmission within 90 days after discharge. Secondary outcomes were mortality, volume, and case mix. RESULTS: A total of 826 BPCI-A participant hospitals were compared with 2016 nonjoining hospitals and 334 late-joining hospitals. Among BPCI-A hospitals, the mean baseline 90-day per-episode Medicare payment was 27,315;thechangeinthequarterlytrendsintheinterventionperiodascomparedwithbaselinewas27,315; the change in the quarterly trends in the intervention period as compared with baseline was -78 per quarter. Among nonjoining hospitals, the mean baseline 90-day per-episode Medicare payment was 25,994;thechangeinquarterlytrendsascomparedwithbaselinewas25,994; the change in quarterly trends as compared with baseline was -26 per quarter (difference between nonjoining hospitals and BPCI-A hospitals, 52[9552 [95% confidence interval {CI}, 34 to 70] per quarter; P\u3c0.001; 0.2% of the baseline payment). Among late-joining hospitals, the mean baseline 90-day per-episode Medicare payment was 26,807; the change in the quarterly trends as compared with baseline was 4perquarter(differencebetweenlatejoininghospitalsandBPCIAhospitals,4 per quarter (difference between late-joining hospitals and BPCI-A hospitals, 82 [95% CI, 41 to 122] per quarter; P\u3c0.001; 0.3% of the baseline payment). There were no meaningful differences in the changes with regard to readmission, mortality, volume, or case mix. CONCLUSIONS: The BPCI-A program was associated with small reductions in Medicare payments among participating hospitals as compared with control hospitals. (Funded by the National Heart, Lung, and Blood Institute.)

    Sugarbeet Production Under Reduced Tillage Prospects And Problems

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    A study was initiated in the fall of 1977 to obtain base line data on the applicability of reduced tillage sugarbeet production in the Red River Valley. Three reduced tillage systems were compared to a conventional system which consisted of fall plow plus secondary tillage. Results indicated warmer early spring soil temperatures, better seedling emergence, lower ground-level wind speed and no significant yield loss under reduced tillage as compared to the conventional system

    Selective Enzymatic Oxidation of Silanes to Silanols

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    Compared to the biological world's rich chemistry for functionalizing carbon, enzymatic transformations of the heavier homologue silicon are rare. We report that a wild‐type cytochrome P450 monooxygenase (P450_(BM3) from Bacillus megaterium, CYP102A1) has promiscuous activity for oxidation of hydrosilanes to give silanols. Directed evolution was applied to enhance this non‐native activity and create a highly efficient catalyst for selective silane oxidation under mild conditions with oxygen as the terminal oxidant. The evolved enzyme leaves C−H bonds present in the silane substrates untouched, and this biotransformation does not lead to disiloxane formation, a common problem in silanol syntheses. Computational studies reveal that catalysis proceeds through hydrogen atom abstraction followed by radical rebound, as observed in the native C−H hydroxylation mechanism of the P450 enzyme. This enzymatic silane oxidation extends nature's impressive catalytic repertoire

    Changes in racial equity associated with participation in the Bundled Payments for Care Improvement Advanced Program

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    IMPORTANCE: The Medicare alternative payment models are designed to incentivize cost reduction and quality improvement, but there are no requirements established for evaluating the outcomes of the Medicare populations. OBJECTIVE: To examine whether participation in the Medicare Bundled Payments for Care Improvement Advanced (BPCI-A) program was associated with narrowing or widening of Black and White racial inequities in outcomes and access. DESIGN, SETTING, AND PARTICIPANTS: Retrospective cohort alternative payment models on equity and quality for disadvantaged populations were studied between April 6, 2021, and August 28, 2022, in US hospitals. Black and White Medicare beneficiaries admitted for any of the 29 inpatient conditions in the BPCI-A program between January 1, 2017, and September 31, 2019, were included. EXPOSURES: BPCI-A participation implemented in 2018. MAIN OUTCOMES AND MEASURES: Ninety-day readmission and mortality, healthy days at home, and proportion of Black patients hospitalized. Segmented regression models were used to examine quarterly changes in slopes for each outcome. RESULTS: The sample included 6 690 336 episodes (6 019 359 White patients, 670 977 Black patients). The population comprised approximately 43% men, 57% women, 17% individuals younger than 65 years, 47% between ages 65 and 80 years, and 36% older than 80 years. Prior to implementation of the BPCI-A program, compared with episodes for White patients, Black patients had higher 90-day readmissions (36.3% vs 29.6%), similar 90-day mortality (12.3% vs 13.3%), and fewer healthy days at home (mean, 68.5 vs 69.5 days). BPCI-A participation was not associated with significant changes in the racial gap in readmissions but was associated with a greater gain in heathy days at home (differences by race, -0.07 days per quarter; 95% CI, -0.12 to -0.01 days per quarter). Among Black patients admitted to BPCI-A hospitals vs controls, healthy days at home increased by 0.09 more days/episode per quarter (95% CI, 0.02-0.17 days/episode per quarter). The proportion of Black patients decreased similarly at BPCI-A and control hospitals. CONCLUSIONS AND RELEVANCE: In this cohort study, BPCI-A participation was not associated with improvements in racial inequities in clinical outcomes. Black patients in BPCI-A had a slight gain in healthy days at home; there were no changes in access. The findings of this study suggest that more needs to be done if payment policy reform is going to be part of the efforts to address glaring racial inequities in health care quality and outcomes. These findings support a need for payment policy reform specifically targeting equity-enhancing programs
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