On the informational efficiency of simple scoring rules

efficient information aggregation, scoring rules, Poisson games, approval voting

Statistical Analysis of Multi-Antenna Relay Systems and Power Allocation Algorithms in a Relay with Partial Channel State Information

The performance of a dual-hop MIMO relay network is studied in this paper. The relay is assumed to have access to the statistical channel state information of its preceding and following channels and it is assumed that fading at the antennas of the relay is correlated. The cumulative density function (cdf) of the received SNR at the destination is first studied and closed-form expressions are derived for the asymptotic cases of the fully-correlated and non-correlated scenarios; moreover, the statistical characteristics of the SNR are further studied and an approximate cdf of the SNR is derived for arbitrary correlation. The cdf is a multipartite function which does not easily lend itself to further mathematical calculations, e.g., rate optimization. However, we use it to propose a simple power allocation algorithm which we call "proportional power allocation". The algorithm is explained in detail for the case of two antennas and three antennas at the relay and the extension of the algorithm to a relay with an arbitrary number of the antennas is discussed. Although the proposed method is not claimed to be optimal, the result is indistinguishable from the benchmark obtained using exhaustive search. The simplicity of the algorithm combined with its precision is indeed attractive from the practical point of view

On a three-alternative Condorcet jury theorem

We investigate whether the simple plurality rule aggregates information efficiently in a large election with three alternatives. The environment is the same as in the Condorcet Jury Theorem (Condorcet (1785)). Voters have common preferences that depend on the unknown state of nature, and they receive imprecise private signals about the state of nature prior tovoting. With two alternatives and strategic voters, the simple plurality rule aggregates information efficiently in elections with two alternatives (e.g., Myerson (1998)). We show that there always exists an efficient equilibrium under the simple plurality rule when there are three alternatives as well. We characterize the set of inefficient equilibria with two alternatives and the condition under which they exist. There is only one type of inefficient equilibrium with two alternatives. In this equilibrium, voters vote unresponsively because they all vote for the same alternative. Under the same condition, the same type of equilibrium exists with three alternatives. However, we show that the number and types of coordination failures increase with three alternatives, and that this leads to the existence of other types of inefficient equilibria as well, including those in which voters vote informatively

Microbubble shape oscillations excited through ultrasonic parametric driving\ud

An air bubble driven by ultrasound can become shape-unstable through a parametric instability. We report time-resolved optical observations of shape oscillations (mode n=2 to 6) of micron-sized single air bubbles. The observed mode number n was found to be linearly related to the ambient radius of the bubble. Above the critical driving pressure threshold for shape oscillations, which is minimal at the resonance of the volumetric radial mode, the observed mode number n is independent of the forcing pressure amplitude. The microbubble shape oscillations were also analyzed numerically by introducing a small nonspherical linear perturbation to a Rayleigh-Plesset-type equation, capturing the experimental observations in detail.\ud \u

Beyond spinal manipulation: should Medicare expand coverage for chiropractic services? A review and commentary on the challenges for policy makers

Objectives: Private insurance plans typically reimburse doctors of chiropractic for a range of clinical services, but Medicare reimbursements are restricted to spinal manipulation procedures. Medicare pays for evaluations performed by medical and osteopathic physicians, nurse practitioners, physician assistants, podiatrists, physical therapists, and occupational therapists; however, it does not reimburse the same services provided by chiropractic physicians. Advocates for expanded coverage of chiropractic services under Medicare cite clinical effectiveness and patient satisfaction, whereas critics point to unnecessary services, inadequate clinical documentation, and projected cost increases. To further inform this debate, the purpose of this commentary is to address the following questions: (1) What are the barriers to expand coverage for chiropractic services? (2) What could potentially be done to address these issues? (3) Is there a rationale for Centers for Medicare and Medicaid Services to expand coverage for chiropractic services? Methods: A literature search was conducted of Google and PubMed for peer-reviewed articles and US government reports relevant to the provision of chiropractic care under Medicare. We reviewed relevant articles and reports to identify key issues concerning the expansion of coverage for chiropractic under Medicare, including identification of barriers and rationale for expanded coverage. Results: The literature search yielded 29 peer-reviewed articles and 7 federal government reports. Our review of these documents revealed 3 key barriers to full coverage of chiropractic services under Medicare: inadequate documentation of chiropractic claims, possible provision of unnecessary preventive care services, and the uncertain costs of expanded coverage. Our recommendations to address these barriers include the following: individual chiropractic physicians, as well as state and national chiropractic organizations, should continue to strengthen efforts to improve claims and documentation practices; and additional rigorous efficacy/effectiveness research and clinical studies for chiropractic services need to be performed. Research of chiropractic services should target the triple aim of high-quality care, affordability, and improved health. Conclusions: The barriers that were identified in this study can be addressed. To overcome these barriers, the chiropractic profession and individual physicians must assume responsibility for correcting deficiencies in compliance and documentation; further research needs to be done to evaluate chiropractic services; and effectiveness of extended episodes of preventive chiropractic care should be rigorously evaluated. Centers for Medicare and Medicaid Services policies related to chiropractic reimbursement should be reexamined using the same standards applicable to other health care providers. The integration of chiropractic physicians as fully engaged Medicare providers has the potential to enhance the capacity of the Medicare workforce to care for the growing population. We recommend that Medicare policy makers consider limited expansion of Medicare coverage to include, at a minimum, reimbursement for evaluation and management services by chiropractic physicians

Analytical parametrization and shape classification of anomalous HH production in the EFT approach

20 pages, 10 figures, LHC Higgs Cross Section Working Group report http://cds.cern.ch/record/2199287In this document we study the effect of anomalous Higgs boson couplings on non-resonant pair production of Higgs bosons ($HH$) at the LHC. We explore the space of the five parameters $\kappa_{\lambda}$, $\kappa_{t}$, $c_2$, $c_g$, and $c_{2g}$ in terms of the corresponding kinematics of the final state, and describe a partition of the space into a limited number of regions featuring similar phenomenology in the kinematics of $HH$ final state. We call clusters the sets of points belonging to the same region; to each cluster corresponds a representative point which we call a benchmark. We discuss a possible technique to estimate the sensitivity of an experimental search to the kinematical differences between the phenomenology of the benchmark points and the rest of the parameter space contained in the corresponding cluster. We also provide an analytical parametrization of the cross-section modifications that the variation of anomalous couplings produces with respect to standard model $HH$ production along with a recipe to translate the results into other parameter-space bases. Finally, we provide a preliminary analysis of variations in the topology of the final state within each region based on recent LHC results