4,566 research outputs found
SCF E3 Ligase Substrates Switch from CAN-D to Can-ubiquitylate
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
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
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
For many stochastic processes there is an underlying coordinate space, ,
with the process moving from point to point in or on variables (such as
spin configurations) defined with respect to . There is a matrix of
transition probabilities (whether between points in or between variables
defined on ) 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
Relative momentum for identical particles
Possible definitions for the relative momentum of identical particles are
considered
Stability of quantum breathers
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
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
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
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
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 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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