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Given the pressures for health care reform, interest in the concept of integrated or organized delivery systems as a means to offer more coordinated cost-effective care is growing. This article has two primary objectives: (1) to clarify the different types of integration associated with the notion of an organized delivery system, and (2) to share the results from an ongoing study of 12 organized delivery systems. The findings indicate a moderate level of integration overall, particularly in the areas of culture, financial planning, and strategic planning. The study found that corporate staff respondents perceive their systems to be more integrated and effective than do operating unit managers, and that some functional integration areas are positively associated with both physician-system and clinical integration that, in turn, are positively related to each other. Overall, perceived integration was found to be positively associated with perceived effectiveness.
An option is a short-term skill consisting of a control policy for a specified region of the state space, and a termination condition recognizing leaving that region. In prior work, we proposed an algorithm called Deep Discovery of Options (DDO) to discover options to accelerate reinforcement learning in Atari games. This paper studies an extension to robot imitation learning, called Discovery of Deep Continuous Options (DDCO), where low-level continuous control skills parametrized by deep neural networks are learned from demonstrations. We extend DDO with: (1) a hybrid categorical-continuous distribution model to parametrize high-level policies that can invoke discrete options as well continuous control actions, and (2) a cross-validation method that relaxes DDO's requirement that users specify the number of options to be discovered. We evaluate DDCO in simulation of a 3-link robot in the vertical plane pushing a block with friction and gravity, and in two physical experiments on the da Vinci surgical robot, needle insertion where a needle is grasped and inserted into a silicone tissue phantom, and needle bin picking where needles and pins are grasped from a pile and categorized into bins. In the 3-link arm simulation, results suggest that DDCO can take 3x fewer demonstrations to achieve the same reward compared to a baseline imitation learning approach. In the needle insertion task, DDCO was successful 8/10 times compared to the next most accurate imitation learning baseline 6/10. In the surgical bin picking task, the learned policy successfully grasps a single object in 66 out of 99 attempted grasps, and in all but one case successfully recovered from failed grasps by retrying a second time.
The Great Depression of the 1930s and the Great Credit Crisis of the 2000s had similar causes but elicited strikingly different policy responses. While it remains too early to assess the effectiveness of current policy, it is possible to analyse monetary and fiscal responses in the 1930s as a natural experiment or counterfactual capable of shedding light on the impact of current policies. We employ vector autoregressions, instrumental variables, and qualitative evidence for 27 countries in the period 1925–39. The results suggest that monetary and fiscal stimulus was effective -- that where it did not make a difference it was not tried. They shed light on the debate over fiscal multipliers in episodes of financial crisis. They are consistent with multipliers at the higher end of those estimated in the recent literature, and with the argument that the impact of fiscal stimulus will be greater when banking systems are dysfunctional and monetary policy is constrained by the zero bound.— Miguel Almunia, Agustín Bénétrix, Barry Eichengreen, Kevin H. O’Rourke and Gisela Rua
: A study was conducted to improve the quality and performance of leads loaded with Composition A-5. The effect of parameters, such as stearic acid content, HMX content, and RDX particle size, on Comp A-5 sensitivity was examined. Parameters affecting load uniformity and output studied were A-5 particle size and density. Results show A-5 particle size had the greatest effect on lead performance and quality.
Racial disparity in academia is a widely acknowledged problem. The quantitative understanding of racial based systemic inequalities is an important step towards a more equitable research system. However, because of the lack of robust information on authors' race, few large scale analyses have been performed on this topic. Algorithmic approaches offer one solution, using known information about authors, such as their names, to infer their perceived race. As with any other algorithm, the process of racial inference can generate biases if it is not carefully considered. The goal of this article is to assess the extent to which algorithmic bias is introduced using different approaches for name based racial inference. We use information from the U.S. Census and mortgage applications to infer the race of U.S. affiliated authors in the Web of Science. We estimate the effects of using given and family names, thresholds or continuous distributions, and imputation. Our results demonstrate that the validity of name based inference varies by race/ethnicity and that threshold approaches underestimate Black authors and overestimate White authors. We conclude with recommendations to avoid potential biases. This article lays the foundation for more systematic and less biased investigations into racial disparities in science.
Recent high-cycle fatigue (HCF) related failures of gas-turbine jet engines have prompted a re-examination of the design methodologies for HCF-critical components, such as titanium alloy turbine blades. As foreign-object damage (FOD) from ingested debris is a key concern for HCF-related failures of such blades, the current study is focused on the role of simulated high velocity FOD in affecting the initiation and early growth of small surface fatigue cracks in a Ti–6Al–4V alloy, processed for typical blade applications. It is found that resistance to HCF is markedly reduced, primarily due to earlier fatigue crack initiation. The mechanistic effect of FOD on such premature fatigue crack initiation and the subsequent crack growth is discussed in terms of four prominent factors: (i) the presence of small microcracks in the damaged zone; (ii) the stress concentration associated with the FOD indentation; (iii) the localized presence of tensile residual hoop stresses at the base and rim of the indent sites; and (iv) microstructural damage from FOD-induced plastic deformation. In view of the in-service conditions, i.e., small crack sizes, high frequency (>1 kHz) vibratory loading and (depending on the blade span location) high mean stress levels, a damage-tolerant design approach, based on the concept of a threshold for no fatigue-crack growth, appears to offer a preferred solution. It is shown that FOD-initiated cracks that are of a size comparable with microstructural dimensions can propagate at applied stress-intensity ranges on the order of ΔK∼1 MPa√m.
view Abstract Citations (37) References (33) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Early-Time Spectra of Type IC Supernovae: Further Evidence for the Presence of Hydrogen Filippenko, Alexei V. Abstract Comparison of the early-time optical spectra of the Type II SN 1985L and the Type Ic SN 1987M confirms the previously suspected presence of Hα in SN 1987M. The Hα line has a P Cygni profile in both objects, but it is not as prominent as in the Type II SN 1987K, whose spectrum at late times became indistinguishable from that of SNs Ic. A spectrum of the Type Ic SN 1991A reveals a weak but nearly unmistakable Hα emission line; faint Hα emission may also be present in the Type Ic SN 1990aa. These observations support the hypothesis that SNs Ic and SNs II are physically related, with the main variable being the amount of hydrogen in the outer envelope. The fact that O I λ7774 absorption is strong in the early-time spectra of SNs Ic, but absent in the corresponding spectra of SNs II, may be consistent with this hypothesis. However, the data do not yet conclusively eliminate white dwarf models for SNs Ic. Publication: The Astrophysical Journal Pub Date: January 1992 DOI: 10.1086/186257 Bibcode: 1992ApJ...384L..37F Keywords: H Alpha Line; Stellar Spectra; Supernovae; Visible Spectrum; White Dwarf Stars; Emission Spectra; Line Spectra; Astrophysics; STARS: SUPERNOVAE: INDIVIDUAL ALPHANUMERIC: SN 1985L; STARS: SUPERNOVAE: INDIVIDUAL ALPHANUMERIC: SN 1987M; STARS: WHITE DWARFS full text sources ADS | data products NED (10) SIMBAD (5)
