4,566 research outputs found

    SCF E3 Ligase Substrates Switch from CAN-D to Can-ubiquitylate

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    Liu et al. (2018) report a mathematical model predicting how the cellular repertoire of SCF E3 ligases is assembled by “adaptive exchange on demand,” with the limited pool of CUL1 scanning the vast sea of F-box proteins for those with substrates demanding ubiquitylation

    Structure and time-dependence of quantum breathers

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    Quantum states of a discrete breather are studied in two ways. One method involves numerical diagonalization of the Hamiltonian, the other uses the path integral to examine correlations in the eigenstates. In both cases only the central nonlinearity is retained. To reduce truncation effects in the numerical diagonalization, a basis is used that involves a quadratic local mode. A similar device is used in the path integral method for deducing localization. Both approaches lead to the conclusion that aside from quantum tunneling the quantized discrete breather is stable.Comment: 33 pages, 20 figures, to appear in J. Chem. Phy

    A Cautious Path Forward on Accountable Care Organizations

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    The wave of new Accountable Care Organizations (ACOs), spurred by financial incentives in the Affordable Care Act, could become the latest chapter in the steady accumulation of market power by hospitals, health care systems, and physician groups. The main purpose behind forming many ACOs may not be to achieve cost savings but instead to strengthen negotiating power over purchasers in the private sector. This would be an unfortunate sequel to the waves of mergers in the 1990s when health care entities sought to counter market pressure from managed care organizations. The possibility that ACOs might further concentrate health care markets brings new urgency to understanding why provider monopolies are pernicious and to considering how government can ensure that ACOs pursue efficiency rather than market power

    Imaging geometry through dynamics: the observable representation

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    For many stochastic processes there is an underlying coordinate space, VV, with the process moving from point to point in VV or on variables (such as spin configurations) defined with respect to VV. There is a matrix of transition probabilities (whether between points in VV or between variables defined on VV) and we focus on its ``slow'' eigenvectors, those with eigenvalues closest to that of the stationary eigenvector. These eigenvectors are the ``observables,'' and they can be used to recover geometrical features of VV

    Relative momentum for identical particles

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    Possible definitions for the relative momentum of identical particles are considered

    Stability of quantum breathers

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    Using two methods we show that a quantized discrete breather in a 1-D lattice is stable. One method uses path integrals and compares correlations for a (linear) local mode with those of the quantum breather. The other takes a local mode as the zeroth order system relative to which numerical, cutoff-insensitive diagonalization of the Hamiltonian is performed.Comment: 4 pages, 3 figure

    Liquid droplets on a free-standing glassy membrane: deformation through the glass transition

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    In this study, micro-droplets are placed on thin, glassy, free-standing films where the Laplace pressure of the droplet deforms the free-standing film, creating a bulge. The film's tension is modulated by changing temperature continuously from well below the glass transition into the melt state of the film. The contact angle of the liquid droplet with the planar film as well as the angle of the bulge with the film are measured and found to be consistent with the contact angles predicted by a force balance at the contact line.Comment: 6 pages, 5 figure

    Pharmaceutical M&A Activity: Effects on Prices, Innovation, and Competition

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    The rise of blockbuster pharmaceutical acquisitions has prompted fears that unprecedented market concentration will weaken competition. Two of the most prominent concerns focus on the upstream and downstream ends of the pharmaceutical industry: (1) the concern that these mergers will concentrate the market for discovery and will therefore lead to fewer discoveries; and (2) the concern that merging large marketing, sales, and distribution forces will strengthen the hands of select pharmaceutical manufacturers and weaken downstream competition. Having considered potential dynamic effects in the industry and conducted a series of preliminary interviews with knowledgeable observers, though, this Article argues that neither of these common fears is systematically warranted. There are, however, potential dangers in market concentration at an intermediate stage during the discovery-to-development path: the stage for regulatory approval. These preliminary findings are a product of dramatic changes that are currently reshaping the structure of the pharmaceutical industry. This Article discusses how these structural changes contribute to the current merger wave, how dynamic responses by industry players in response to the merger wave mitigate the potential harm from competition, and how the political arena might still offer threats to market concentration

    Overbilling and Informed Financial Consent — A Contractual Solution

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    U.S. hospitals and physicians regularly charge uninsured patients and patients receiving care outside their health-plan networks far more what most health insurers pay and far more than their actual costs. Such practices have triggered over 100 lawsuits and prompted calls for pricing transparency in Congress and price regulation in several states. This Perspective argues that the theory of implied contracts, a foundation in most first-year courses in contract law, offers a useful legal and ethical mechanism for handling these troubling problems in health care billing

    Lessons From India in Organizational Innovation: A Tale of Two Heart Hospitals

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    Recent discussions in health reform circles have pinned great hopes on the prospect of innovation as the solution to the high-cost, inadequate-quality U.S. health system. But U.S. health care institutions--insurers, providers and specialists--have ceded leadership in innovation to Indian hospitals such as Care Hospital in Hyderabad and the Fortis Hospitals around New Delhi, which have U.S.-trained doctors and can perform open heart surgery for 6000(comparedto6000 (compared to 100,000 in the United States). The Indian success is a window into America\u27s stalemate with inflating costs and stagnant innovation
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