4,014 research outputs found
The Promise of Priority Review Vouchers as a Legislative Tool to Encourage Drugs for Neglected Diseases
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
We introduce a feedback control algorithm that increases the speed at which a
measurement extracts information about a -dimensional system by a factor
that scales as . Generalizing this algorithm, we apply it to a register of
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
Writer Identification Using Inexpensive Signal Processing Techniques
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
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
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
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
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
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
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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