4,014 research outputs found

    The Promise of Priority Review Vouchers as a Legislative Tool to Encourage Drugs for Neglected Diseases

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    Despite the intellectual property system’s success in promoting the economic well-being of the United States, this system has not achieved all socially valuable ends. Insufficient treatments are applied both to diseases endemic in developing countries, such as malaria, and rare diseases, such as rare childhood cancers. Several legislative tools aim to promote socially valuable drugs and biologics through market incentives. The priority review voucher (PRV) program is the latest and most unique of these legislative tools aimed at encouraging the development of drugs for neglected diseases without burdening taxpayers. The Creating Hope Act—recently signed into law as part of the Food & Drug Administration Safety & Innovation Act—extends the PRV program to rare pediatric diseases. This Issue Brief argues that some provisions in this new legislation may result in undesirable collateral effects that could prevent the legislation from fulfilling its objective of encouraging investment in treatments for rare pediatric diseases

    Rapid Measurement of Quantum Systems using Feedback Control

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    We introduce a feedback control algorithm that increases the speed at which a measurement extracts information about a dd-dimensional system by a factor that scales as d2d^2. Generalizing this algorithm, we apply it to a register of nn qubits and show an improvement O(n). We derive analytical bounds on the benefit provided by the feedback and perform simulations that confirm that this speedup is achieved.Comment: 4 pages, 4 figures. V2: Minor correction

    La irraonable efectivitat de les matemàtiques

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    Writer Identification Using Inexpensive Signal Processing Techniques

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    We propose to use novel and classical audio and text signal-processing and otherwise techniques for "inexpensive" fast writer identification tasks of scanned hand-written documents "visually". The "inexpensive" refers to the efficiency of the identification process in terms of CPU cycles while preserving decent accuracy for preliminary identification. This is a comparative study of multiple algorithm combinations in a pattern recognition pipeline implemented in Java around an open-source Modular Audio Recognition Framework (MARF) that can do a lot more beyond audio. We present our preliminary experimental findings in such an identification task. We simulate "visual" identification by "looking" at the hand-written document as a whole rather than trying to extract fine-grained features out of it prior classification.Comment: 9 pages; 1 figure; presented at CISSE'09 at http://conference.cisse2009.org/proceedings.aspx ; includes the the application source code; based on MARF described in arXiv:0905.123

    A generalization of Hausdorff dimension applied to Hilbert cubes and Wasserstein spaces

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    A Wasserstein spaces is a metric space of sufficiently concentrated probability measures over a general metric space. The main goal of this paper is to estimate the largeness of Wasserstein spaces, in a sense to be precised. In a first part, we generalize the Hausdorff dimension by defining a family of bi-Lipschitz invariants, called critical parameters, that measure largeness for infinite-dimensional metric spaces. Basic properties of these invariants are given, and they are estimated for a naturel set of spaces generalizing the usual Hilbert cube. In a second part, we estimate the value of these new invariants in the case of some Wasserstein spaces, as well as the dynamical complexity of push-forward maps. The lower bounds rely on several embedding results; for example we provide bi-Lipschitz embeddings of all powers of any space inside its Wasserstein space, with uniform bound and we prove that the Wasserstein space of a d-manifold has "power-exponential" critical parameter equal to d.Comment: v2 Largely expanded version, as reflected by the change of title; all part I on generalized Hausdorff dimension is new, as well as the embedding of Hilbert cubes into Wasserstein spaces. v3 modified according to the referee final remarks ; to appear in Journal of Topology and Analysi

    Trajectory generation for road vehicle obstacle avoidance using convex optimization

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    This paper presents a method for trajectory generation using convex optimization to find a feasible, obstacle-free path for a road vehicle. Consideration of vehicle rotation is shown to be necessary if the trajectory is to avoid obstacles specified in a fixed Earth axis system. The paper establishes that, despite the presence of significant non-linearities, it is possible to articulate the obstacle avoidance problem in a tractable convex form using multiple optimization passes. Finally, it is shown by simulation that an optimal trajectory that accounts for the vehicle’s changing velocity throughout the manoeuvre is superior to a previous analytical method that assumes constant speed

    Ordered Measurements of Permutationally-Symmetric Qubit Strings

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    We show that any sequence of measurements on a permutationally-symmetric (pure or mixed) multi-qubit string leaves the unmeasured qubit substring also permutationally-symmetric. In addition, we show that the measurement probabilities for an arbitrary sequence of single-qubit measurements are independent of how many unmeasured qubits have been lost prior to the measurement. Our results are valuable for quantum information processing of indistinguishable particles by post-selection, e.g. in cases where the results of an experiment are discarded conditioned upon the occurrence of a given event such as particle loss. Furthermore, our results are important for the design of adaptive-measurement strategies, e.g. a series of measurements where for each measurement instance, the measurement basis is chosen depending on prior measurement results.Comment: 13 page

    Numerical Analysis of Boosting Scheme for Scalable NMR Quantum Computation

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    Among initialization schemes for ensemble quantum computation beginning at thermal equilibrium, the scheme proposed by Schulman and Vazirani [L. J. Schulman and U. V. Vazirani, in Proceedings of the 31st ACM Symposium on Theory of Computing (STOC'99) (ACM Press, New York, 1999), pp. 322-329] is known for the simple quantum circuit to redistribute the biases (polarizations) of qubits and small time complexity. However, our numerical simulation shows that the number of qubits initialized by the scheme is rather smaller than expected from the von Neumann entropy because of an increase in the sum of the binary entropies of individual qubits, which indicates a growth in the total classical correlation. This result--namely, that there is such a significant growth in the total binary entropy--disagrees with that of their analysis.Comment: 14 pages, 18 figures, RevTeX4, v2,v3: typos corrected, v4: minor changes in PROGRAM 1, conforming it to the actual programs used in the simulation, v5: correction of a typographical error in the inequality sign in PROGRAM 1, v6: this version contains a new section on classical correlations, v7: correction of a wrong use of terminology, v8: Appendix A has been added, v9: published in PR

    FDTD Simulation of Thermal Noise in Open Cavities

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    A numerical model based on the finite-difference time-domain (FDTD) method is developed to simulate thermal noise in open cavities owing to output coupling. The absorbing boundary of the FDTD grid is treated as a blackbody, whose thermal radiation penetrates the cavity in the grid. The calculated amount of thermal noise in a one-dimensional dielectric cavity recovers the standard result of the quantum Langevin equation in the Markovian regime. Our FDTD simulation also demonstrates that in the non-Markovian regime the buildup of the intracavity noise field depends on the ratio of the cavity photon lifetime to the coherence time of thermal radiation. The advantage of our numerical method is that the thermal noise is introduced in the time domain without prior knowledge of cavity modes.Comment: 8 pages, 7 figure

    A mycotic aneurysm of the abdominal aorta in a child

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    A 6-year-old boy with a previous history of intracardiac correction of a partial atrioventricular canal defect presented with infective endocarditis. Despite antibiotic therapy and reoperation, he developed a mycotic abdominal aneurysm. In situ aortoiliac reconstruction with a prosthesis and an omental flap was performed. At follow-up after 2 {Mathematical expression} years there were no signs of prosthetic infection or problems with the anastomoses
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