427 research outputs found
Linear High-Order Deterministic Tree Transducers with Regular Look-Ahead
We introduce the notion of high-order deterministic top-down tree transducers (HODT) whose outputs correspond to single-typed lambda-calculus formulas. These transducers are natural generalizations of known models of top-tree transducers such as: Deterministic Top-Down Tree Transducers, Macro Tree Transducers, Streaming Tree Transducers... We focus on the linear restriction of high order tree transducers with look-ahead (HODTR_lin), and prove this corresponds to tree to tree functional transformations defined by Monadic Second Order (MSO) logic. We give a specialized procedure for the composition of those transducers that uses a flow analysis based on coherence spaces and allows us to preserve the linearity of transducers. This procedure has a better complexity than classical algorithms for composition of other equivalent tree transducers, but raises the order of transducers. However, we also indicate that the order of a HODTR_lin can always be bounded by 3, and give a procedure that reduces the order of a HODTR_lin to 3. As those resulting HODTR_lin can then be transformed into other equivalent models, this gives an important insight on composition algorithm for other classes of transducers. Finally, we prove that those results partially translate to the case of almost linear HODTR: the class corresponds to the class of tree transformations performed by MSO with unfolding (not closed by composition), and provide a mechanism to reduce the order to 3 in this case
Quantitative measurement of permeabilization of living cells by terahertz attenuated total reflection
International audienceUsing Attenuated Total Reflection imaging technique in the terahertz domain, we demonstrate non-invasive, non-staining real time measurements of cytoplasm leakage during permeabilization of epithelial cells by saponin. The terahertz signal is mostly sensitive to the intracellular protein concentration in the cells, in a very good agreement with standard bicinchoninic acid protein measurements. It opens the way to in situ real time dynamics of protein content and permeabilization in live cells
Percutaneous Repair of Aortic Aneurysms: A Prospective Study of Suture-Mediated Closure Devices
AbstractPurposeTo evaluate prospectively the safety and efficacy of totally percutaneous placement of abdominal and thoracic aortic endografts using the Prostar XL suture-mediated closure system.MethodsFrom January 2002 to January 2005, we attempted to insert percutaneously all bifurcated abdominal aortic and thoracic endografts. Consecutive patients (25 men, four women), with mean age 74.9 years (range 44–84), underwent endovascular repair for 20 abdominal aortic aneurysms (AAA) and nine thoracic aortic aneurysms (repeat operation in one case).Endografts used included 21 Zenith (Cook), eight Talent (Medtronic), one AneuRx (Medtronic). For the «pre-close» technique, two Prostar XL 8F were used to close 22–24F access sites and one Prostar XL 10F to close 16F access sites.ResultsProcedural success was achieved in 21/29 (72.4%) patients and in 39/47 access sites (83%). Closure of 22–24F access sites with tandem 8F Prostar devices was successful in 23/29 (79.3%) cases. Closure of 16F access sites with 10F Prostar device was successful in 16/18 (88.8%) cases. There were seven peri-procedural failures requiring surgery to repair the femoral artery in three cases. Four access complications healed without intervention. Overall 25/29 (86.2%) patients had complete percutaneous repair. No late complications were detected during follow-up (median 17.5 months).ConclusionsPercutaneous treatment of patients with AAA and thoracic aneurysms is feasible in most cases, with a very low risk of access-related complication, providing that the operator has sufficient practical experience of this technique
Higher dimensional abelian Chern-Simons theories and their link invariants
The role played by Deligne-Beilinson cohomology in establishing the relation
between Chern-Simons theory and link invariants in dimensions higher than three
is investigated. Deligne-Beilinson cohomology classes provide a natural abelian
Chern-Simons action, non trivial only in dimensions , whose parameter
is quantized. The generalized Wilson -loops are observables of the
theory and their charges are quantized. The Chern-Simons action is then used to
compute invariants for links of -loops, first on closed
-manifolds through a novel geometric computation, then on
through an unconventional field theoretic computation.Comment: 40 page
Parallel spinors and holonomy groups
In this paper we complete the classification of spin manifolds admitting
parallel spinors, in terms of the Riemannian holonomy groups. More precisely,
we show that on a given n-dimensional Riemannian manifold, spin structures with
parallel spinors are in one to one correspondence with lifts to Spin_n of the
Riemannian holonomy group, with fixed points on the spin representation space.
In particular, we obtain the first examples of compact manifolds with two
different spin structures carrying parallel spinors.Comment: 10 pages, LaTeX2
Arteriography during ex vivo renal perfusion A complication
A case of bilateral renal-cell carcinoma unsuccessfully treated with bench surgery is reported. The reason for failure was apparently the toxicity of the contrast media used during the ex vivo arteriographic studies. © 1973
Covariance and Fisher information in quantum mechanics
Variance and Fisher information are ingredients of the Cramer-Rao inequality.
We regard Fisher information as a Riemannian metric on a quantum statistical
manifold and choose monotonicity under coarse graining as the fundamental
property of variance and Fisher information. In this approach we show that
there is a kind of dual one-to-one correspondence between the candidates of the
two concepts. We emphasis that Fisher informations are obtained from relative
entropies as contrast functions on the state space and argue that the scalar
curvature might be interpreted as an uncertainty density on a statistical
manifold.Comment: LATE
A natural Finsler--Laplace operator
We give a new definition of a Laplace operator for Finsler metric as an
average with regard to an angle measure of the second directional derivatives.
This definition uses a dynamical approach due to Foulon that does not require
the use of connections nor local coordinates. We show using 1-parameter
families of Katok--Ziller metrics that this Finsler--Laplace operator admits
explicit representations and computations of spectral data.Comment: 25 pages, v2: minor modifications, changed the introductio
Quantifying the performance of a hybrid anion exchanger/adsorbent for phosphorus removal using mass spectrometry coupled with batch kinetic trials
Increasingly stricter phosphorus discharge limits represent a significant challenge for the wastewater industry. Hybrid media comprising anionic exchange resins with dispersions of hydrated ferric oxide nanoparticles have been shown to selectively remove phosphorus from wastewaters, and display greater capacity and operational capability than both conventional treatment techniques and other ferric-based adsorbent materials. Spectrographic analyses of the internal surfaces of a hybrid media during kinetic experiments show that the adsorption of phosphorus is very rapid, utilising 54% of the total capacity of the media within the first 15 min and 95% within the first 60 min. These analyses demonstrate the importance of intraparticle diffusion on the overall rate in relation to the penetration of phosphorus. Operational capacity is a function of the target effluent phosphorus concentration and for 0.1 mg P L−1, this is , which is 8–13% of the exhaustive capacity. The adsorbed phosphorus can be selectively recovered, offering a potential route to recycle this important nutrient. The main implication of the work is that the ferric nanoparticle adsorbent can provide a highly effective means of achieving a final effluent phosphorus concentration of 0.1 mg P L−1, even when treating sewage effluent at 5 mg P L−1
Quantum projection filter for a highly nonlinear model in cavity QED
Both in classical and quantum stochastic control theory a major role is
played by the filtering equation, which recursively updates the information
state of the system under observation. Unfortunately, the theory is plagued by
infinite-dimensionality of the information state which severely limits its
practical applicability, except in a few select cases (e.g. the linear Gaussian
case.) One solution proposed in classical filtering theory is that of the
projection filter. In this scheme, the filter is constrained to evolve in a
finite-dimensional family of densities through orthogonal projection on the
tangent space with respect to the Fisher metric. Here we apply this approach to
the simple but highly nonlinear quantum model of optical phase bistability of a
stongly coupled two-level atom in an optical cavity. We observe near-optimal
performance of the quantum projection filter, demonstrating the utility of such
an approach.Comment: 19 pages, 6 figures. A version with high quality images can be found
at http://minty.caltech.edu/papers.ph
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