cssi/SciSciGPT-SciSciNet huggingface dataset:
Hilbert space representations of decoherence functionals and quantum measures

We show that any decoherence functional D can be represented by a spanning vector-valued measure on a complex Hilbert space. Moreover, this representation is unique up to an isomorphism when the system is finite. We consider the natural map U from the history Hilbert space K to the standard Hilbert space H of the usual quantum formulation. We show that U is an isomorphism from K onto a closed subspace of H and that U is an isomorphism from K onto H if and only if the representation is spanning. We then apply this work to show that a quantum measure has a Hilbert space representation if and only if it is strongly positive. We also discuss classical decoherence functionals, operator-valued measures and quantum operator measures.
Economy of large launch vehicles including orbital labor cost

Conceptual design of reusable launch vehicle, termed chemical nexus concept, as improvement on orbital payload capability of Saturn V launch vehicle
Limited Attention and the Optimal Incompleteness of Contracts

A decision-maker's limited attention is allocated between writing new contracts and directing current contracts. More time spent writing a new contract makes the contract more complete. A more complete contract performs better and generates higher returns. The optimal allocation of attention implies two types of contracts, relational and market. A relational contract, which is directed periodically, is optimally less complete than a market contract, which is not directed. The completeness of relational contracts decreases with the ability to direct contracts, since changing circumstances can be dealt with later. In addition, the completeness of relational contracts increases with the ability to write new contracts, since more complete relational contracts are directed less frequently and leave more time for writing new contracts. The optimal allocation of attention to relational contracts is socially efficient even though it does not maximize the discounted expected returns of the firm.
TeV right-handed neutrinos and the flavor-symmetry-improved seesaw mechanism

Abstract Horizontal flavor symmetries can drastically suppress Dirac neutrino masses well below those of the corresponding charged leptons. We show that models can be constructed where the light neutrino mass eigenvalues are small enough to give the MSW solution to the solar neutrino problem, with a right-handed neutrino scale no larger than a TeV. We present a model of this type where the right-handed neutrino scale is generated by the spontaneous breakdown of gauged U(1) B-L , in a radiative breaking scenario driven by the right-handed neutrino Yukawa couplings. The model allows for a solution to the μ problem, and predicts the existence of a Z ′ boson within the reach of the LHC or the Tevatron.
Viewing morphology as an inference process

Abstract Morphology is the area of linguistics concerned with the internal structure of words. Information retrieval has generally not paid much attention to word structure, other than to account for some of the variability in word forms via the use of stemmers. We report on our experiments to determine the importance of morphology, and the effect that it has on performance. We found that grouping morphological variants makes a significant improvement in retrieval performance. Improvements are seen by grouping inflectional as well as derivational variants. We also found that performance was enhanced by recognizing lexical phrases. We describe the interaction between morphology and lexical ambiguity, and how resolving that ambiguity will lead to further improvements in performance.
Revocation Systems with Very Small Private Keys

In this work, we design a method for creating public key broadcast encryption systems. Our main technical innovation is based on a new "two equation" technique for revoking users. This technique results in two key contributions: First, our new scheme has ciphertext size overhead $O(r)$, where $r$ is the number of revoked users, and the size of public and private keys is only a \emph{constant} number of group elements from an elliptic-curve group of prime order. In addition, the public key allows us to encrypt to an unbounded number of users. Our system is the first to achieve such parameters. We give two versions of our scheme: a simpler version which we prove to be selectively secure in the standard model under a new, but non-interactive assumption, and another version that employs the new dual system encryption technique of Waters to obtain adaptive security under the d-BDH and decisional Linear assumptions. Second, we show that our techniques can be used to realize Attribute-Based Encryption (ABE) systems with non-monotonic access formulas, where our key storage is significantly more efficient than previous solutions. This result is also proven selectively secure in the standard model under our new non-interactive assumption.
Measurements of ionization produced in silicon crystals by low-energy silicon atoms.

We measured the ionization and the fluctuations in ionization produced in a Si(Li) detector by silicon atoms at five particular kinetic energies ranging from about 4 to 109 keV. The method is simple and precise, yet untried until now, and provides excellent calibration points for silicon. Our results are in good agreement with the predictions of Lindhard {ital et} {ital al}. (Mat. Fys. Medd. 33, 10 (1963)).
An accurate, fast, matrix-free implicit method for computing unsteady flows on unstructured grids

Abstract An accurate, fast, matrix-free implicit method has been developed to solve the three-dimensional compressible unsteady flows on unstructured grids. A nonlinear system of equations as a result of a fully implicit temporal discretization is solved at each time step using a pseudo-time marching approach. A newly developed fast, matrix-free implicit method is then used to obtain the steady-state solution to the pseudo-time system. The developed method is applied to compute a variety of unsteady flow problems involving moving boundaries. The numerical results obtained indicate that the use of the present implicit method leads to a significant increase in performance over its explicit counterpart, while maintaining a similar memory requirement.
Personnel neutron dosimetry using hot, low-frequency electrochemical etching

Abstract We have developed an electrochemical-etch procedure for the processing of large numbers of CR-39 dosimeters. Specially designed Homann-Type chambers can etch up to 24 CR-39 chips, or foils, at one time. In our two-step procedure, the second step, called blow-up, increases the tracks' size and makes them relatively uniform. The energy response is fairly flat from ∼ 150 keV to 4.5 MeV, but drops by about a factor of three in the 13–16 MeV range. The sensitivity of the dosimetry system is 6 tracks/mrem with a background of 8 mrem, giving a lower limit of sensitivity of approximately 10 mrem for the dosimeter (when three foils are used). Because greater numbers of CR-39 foils can be accomodated at any one time, our procedure is quite efficient for operations with large numbers of dosimeters to be processed.
Collusion, Discounting and Dynamic Games

Abstract This paper investigates the following claims: in a dynamic game, (i) Pareto-optimal outcomes are sustainable only by patient players and (ii) the set of equilibrium outcomes expands in the discount factor. The intuition for these results, although immediate for purely repeated games, is shown to be incomplete for dynamic games. Consequently, there is no direct link between patience and the sustainability of Pareto-optimal outcomes. In fact, there are dynamic games arbitrarily "close" to a repeated game in which such collusion is facilitated by impatience. However, for a class of dynamic games, any equilibrium outcome that is sustainable by less patient players is also an equilibrium outcome when players are more patient. Journal of Economic Literature Classification Numbers: C73, D90.
DEPUTIZING INSTITUTIONAL REVIEW BOARDS TO POLICE (AUDIT?) BIOMEDICAL RESEARCH

This paper responds to a new article by Carl Coleman that critiques the risk assessment process applied to biomedical research by institutional review boards (IRBs). Coleman's central argument that IRBs exercise delegated governmental authority and should strive to emulate appellate decision making suffers from several flaws: it exaggerates the centrality of these boards in existing systems of human subject protection, it incorrectly adopts a court-centered view of the processes used by other regulatory institutions, and it fails to appreciate some of the countervailing advantages of an underproceduralized decision making model. Human research subject protection efforts suffer from many shortcomings, but it would be a mistake to pursue solutions that recast boards as miniature appellate courts in an effort to promote consistency and transparency when an inquisitorial model akin to mechanisms of peer review better describes the activities of IRBs.
On Effectiveness of Application-Layer Coding

The effectiveness of application-layer coding in a system with a large number of users is considered. The end users encode data packets before transmitting them. The effect of additional packets on the system performance is twofold: (i) additional packets increase offered load, which results in higher drop probability, and (ii) some of dropped packets can be recovered at the receivers after decoding. It is argued that the space of all systems can be partitioned into two regions where coding is beneficial and detrimental, respectively. In particular, the paper establishes an asymptotic regime that contains the boundary between these two regions. On the boundary, systems with and without coding have the same performance. Informally, our results indicate that application-layer coding improves the performance only in systems with low loss probabilities (without coding), and employing such coding in systems with high loss probabilities only degrades the performance.
Quantitative Examination of a Large Sample of Supra-Arcade Downflows in Eruptive Solar Flares

Sunward-flowing voids above post-coronal mass ejection flare arcades were first discovered using the soft X-ray telescope aboard Yohkoh and have since been observed with TRACE (extreme ultraviolet (EUV)), SOHO/LASCO (white light), SOHO/SUMER (EUV spectra), and Hinode/XRT (soft X-rays). Supra-arcade downflow (SAD) observations suggest that they are the cross-sections of thin flux tubes retracting from a reconnection site high in the corona. Supra-arcade downflowing loops (SADLs) have also been observed under similar circumstances and are theorized to be SADs viewed from a perpendicular angle. Although previous studies have focused on dark flows because they are easier to detect and complementary spectral data analysis reveals their magnetic nature, the signal intensity of the flows actually ranges from dark to bright. This implies that newly reconnected coronal loops can contain a range of hot plasma density. Previous studies have presented detailed SAD observations for a small number of flares. In this paper, we present a substantial SADs and SADLs flare catalog. We have applied semiautomatic detection software to several of these events to detect and track individual downflows thereby providing statistically significant samples of parameters such as velocity, acceleration, area, magnetic flux, shrinkage energy, and reconnection rate. We discuss these measurements (particularly the unexpected result of the speeds being an order of magnitude slower than the assumed Alfven speed), how they were obtained, and potential impact on reconnection models.
Flexible complementarity solvers for large-scale applications

Discretizations of infinite-dimensional variational inequalities lead to linear and nonlinear complementarity problems with many degrees of freedom. To solve these problems in a parallel computing environment, we propose two active-set methods that solve only one linear system of equations per iteration. The linear solver, preconditioner, and matrix structures can be chosen by the user for a particular application to achieve high parallel performance. The parallel scalability of these methods is demonstrated for some discretizations of infinite-dimensional variational inequalities.
Biodegradation of polycyclic aromatic hydrocarbons

The intent of this review is to provide an outline of the microbial degradation of polycyclic aromatic hydrocarbons. A catabolically diverse microbial community, consisting of bacteria, fungi and algae, metabolizes aromatic compounds. Molecular oxygen is essential for the initial hydroxylation of polycyclic aromatic hydrocarbons by microorganisms. In contrast to bacteria, filamentous fungi use hydroxylation as a prelude to detoxification rather than to catabolism and assimilation. The biochemical principles underlying the degradation of polycyclic aromatic hydrocarbons are examined in some detail. The pathways of polycyclic aromatic hydrocarbon catabolism are discussed. Studies are presented on the relationship between the chemical structure of the polycyclic aromatic hydrocarbon and the rate of polycyclic aromatic hydrocarbon biodegradation in aquatic and terrestrial ecosystems.
Use of portable ultrasound to assist urine collection by suprapubic aspiration

Study objective: To determine whether portable ultrasound can improve the success rate of suprapubic aspiration (SPA). Design: Patients were randomly assigned to either ultrasound or no ultrasound groups. In the ultrasound group, patients underwent SPA if ultrasound revealed urine in the bladder; if no urine was present, patients underwent catheterization instead of SPA. In the no-ultrasound group, SPA was attempted without ultrasound. All unsuccessful SPAs were followed by catheterization and measurement of urine volume. Setting: Children's hospital-based pediatric emergency department. Participants: Children less than 2 years old who required SPA. Interventions: Ultrasound versus no ultrasound. Results: Thirty-five patients were randomized to the ultrasound group, and 31 were randomized to the no-ultrasound group. SPA was successful in 79% of attempts in the ultrasound group compared with 52% in the no-ultrasound group ( P = .04). The sensitivity and specificity of ultrasound were 90% and 86%, respectively. Conclusion: Portable ultrasound can significantly improve the success rate of SPA and limit nonproductive attempts at SPA.
Signal Recovery From Incomplete and Inaccurate Measurements Via Regularized Orthogonal Matching Pursuit

We demonstrate a simple greedy algorithm that can reliably recover a vector v ? ?d from incomplete and inaccurate measurements x = ?v + e. Here, ? is a N x d measurement matrix with N<<d, and e is an error vector. Our algorithm, Regularized Orthogonal Matching Pursuit (ROMP), seeks to provide the benefits of the two major approaches to sparse recovery. It combines the speed and ease of implementation of the greedy methods with the strong guarantees of the convex programming methods. For any measurement matrix ? that satisfies a quantitative restricted isometry principle, ROMP recovers a signal v with O(n) nonzeros from its inaccurate measurements x in at most n iterations, where each iteration amounts to solving a least squares problem. The noise level of the recovery is proportional to ?{logn} ||e||2. In particular, if the error term e vanishes the reconstruction is exact.
Application of the dual-kinetic-balance sets in the relativistic many-body problem of atomic structure

Abstract The dual-kinetic-balance (DKB) finite basis set method for solving the Dirac equation for hydrogen-like ions [V.M. Shabaev et al., Phys. Rev. Lett. 93 (2004) 130405] is extended to problems with a non-local spherically-symmetric Dirac–Hartree–Fock potential. We implement the DKB method using B-spline basis sets and compare its performance with the widely-employed approach of Notre Dame (ND) group [W.R. Johnson, S.A. Blundell, J. Sapirstein, Phys. Rev. A 37 (1988) 307–315]. We compare the performance of the ND and DKB methods by computing various properties of Cs atom: energies, hyperfine integrals, the parity-non-conserving amplitude of the 6 s 1 / 2 − 7 s 1 / 2 transition, and the second-order many-body correction to the removal energy of the valence electrons. We find that for a comparable size of the basis set the accuracy of both methods is similar for matrix elements accumulated far from the nuclear region. However, for atomic properties determined by small distances, the DKB method outperforms the ND approach. In addition, we present a strategy for optimizing the size of the basis sets by choosing progressively smaller number of basis functions for increasingly higher partial waves. This strategy exploits suppression of contributions of high partial waves to typical many-body correlation corrections.
Soybean Acreage Response in Brazil

This paper advances Williams and Thompson (1984) by updating their work and by explicitly accounting for price and yield risk in the analysis of acreage response in Brazil for soybeans and by assessing model specification. Empirical equations were estimated using seemingly unrelated regression (SUR). The robustness of the model was evaluated in the battery of misspecification tests suggested by McGuirk et al. (1993) and McGuirk et al. (1995). The results of the testing procedure suggest that the model is fairly robust in terms of normality, heteroscedasticity and functional form. The results point to parameter instability in the soybean model. The approach to the problem of parameter instability involved dividing the data in two periods and estimating regressions for each period. The signs of the significant coefficients were consistent with expectation, particularly for the second period. Soybean acreage is explained mainly by past acreage, expected prices of soybeans and land competing crops (cotton, rice, and corn), and price and yield risk. Results suggest that market signals played a reduced role in the soybean acreage growth in early years. In contrast, in recent years producers in Brazil became more sensitive to changes in prices and risk. Measures of short-run price elasticity of soybean acreage response are similar to the one obtained by William and Thompson (1984) for soybean supply. Long-run elasticities are significantly smaller.
Increased throughput for process chromatography using constrained deconvolution

Signal restoration using Jansson's method of constrained deconvolution was investigated and tested to deconvolve and thereby resolve severely overlapped gas chromatographic peaks. The results of this technique were compared to those obtained with an instrument that uses a longer column that already produces fully resolved peaks. Jannson's deconvolution method enabled significant resolution improvement at a minimal cost in computational time. Thus, for a given amount of peak resolution, this technique increased the instrument's throughput by 10 times. Test results show that Jansson's method provides similar measurement accuracies and variances as those obtained on an instrument using a longer column. >
Impact of HRR radar processing on moving target identification performance

Airborne radar tracking in moving ground vehicle scenarios is impacted by sensor, target, and environmental dynamics. Moving targets can be assessed with 1-D High Range Resolution (HRR) Radar profiles with sufficient signal-to-noise (SNR) present which contain enough feature information to discern one target from another to help maintain track or to identify the vehicle. Typical radar clutter suppression algorithms developed for processing moving ground target data not only remove the surrounding clutter but also a portion of the target signature. Enhanced clutter suppression can be achieved using a multi-channel signal subspace (MSS) algorithm which preserves target features. In this paper, we (1) exploit extra information from enhanced clutter suppression for automatic target recognition (ATR), (2) present a gain comparison using displaced phase center antenna (DPCA) and MSS clutter suppressed HRR data; and (3) develop a confusion-matrix identity result for simultaneous tracking and identification (STID). The results show that more channels for MSS increase ID over DCPA, result in a slightly noisier clutter suppressed image, and preserve more target features after clutter cancellation
Supervised inductive learning with Lotka–Volterra derived models

We present a classification algorithm built on our adaptation of the Generalized Lotka–Volterra model, well-known in mathematical ecology. The training algorithm itself consists only of computing several scalars, per each training vector, using a single global user parameter and then solving a linear system of equations. Construction of the system matrix is driven by our model and based on kernel functions. The model allows an interesting point of view of kernels’ role in the inductive learning process. We describe the model through axiomatic postulates. Finally, we present the results of the preliminary validation experiments.
Humanoids for lunar and planetary surface operations

This paper presents a vision of humanoid robots as human's key partners in future space exploration, in particular for construction, maintenance/repair and operation of lunar/planetary habitats, bases and settlements. It integrates this vision with the recent plans for human and robotic exploration, aligning a set of milestones for operational capability of humanoids with the schedule for the next decades and development spirals in the Project Constellation. These milestones relate to a set of incremental challenges, for the solving of which new humanoid technologies are needed. A system of systems integrative approach that would lead to readiness of cooperating humanoid crews is sketched. Robot fostering, training/education techniques, and improved cognitive/sensory/motor development techniques are considered essential elements for achieving intelligent humanoids. A pilot project in this direction is outlined.
Spectroscopic Signatures of the Tidal Disruption of Stars by Massive Black Holes

During the tidal disruption of a main sequence star by a massive black hole (BH) having mass MBH � 10 7 M� , the stellar debris falls back to the BH at a rate well above the Eddington rate. Some fraction of this gas is subsequently blown away from the BH, producing an optically bright flare of radiation. We predict the spectra and spectral evolution of tidal disruption events, focusing on the signatures produced by photoionized gas outside the photosphere of this super-Eddington outflow. The spectrum of such an outflow will show absorption lines that are strongly blueshifted relative to the host galaxy, are typically very broad (0:01 0:1c), and are most prominent at ultraviolet wavelengths (e.g., C IV, Lyman �, O VI) at early times ( � 1 month for a
On computing the maximal delay intervals for stability of linear delay systems

This note is concerned with stability properties of linear time-invariant delay systems. The authors consider delay systems of both retarded and neutral types expressed in state-space forms. The author's main goal is to provide a computation-oriented method for computing the maximal delay intervals over which the systems under consideration maintain stability. The author's results show that this can be accomplished by computing the generalized eigenvalues of certain frequency-dependent matrices. Based on these results, the author also states a necessary and sufficient condition concerning stability independent of delay for each of the retarded and neutral systems. The author's results can be readily implemented and appear suitable for analyzing systems with high dimensions and many delay units. >
Low-cost testing of high-density logic components

The evolution of a testing method and architecture of a logic-device tester to be used for the next generation of IBM's high-density CMOS ASIC (application-specific integrated circuit) logic components is described. The tester's design is based on the architecture of an existing IBM memory tester rather than on a conventional logic-tester design. The testing strategy calls for boundary-scan in each component design, built-in self-test logic within embedded memory arrays, and the use of weighted random-pattern logic testing. The development of the tester hardware is discussed, and capital costs of the new tester are compared with those of other approaches. >
Services Computing: A New Thinking Style of Education and Engineering

Summary form only given. Services computing has become a foundational discipline of modernizing services and software industry. Services computing curriculum initiative (SCCI) is a community-driven professional activity which is sponsored by the IEEE computer society technical committee on services computing (TC-SVC). This session will present the latest advancements of SCCI in terms of newly formalized knowledge areas, case studies, and best practices of creating and delivering services computing courses. Several adoption approaches were introduced based on co-design and reuse principles for various degree programs. This paper also shares with you some long-term visions and latest lessons learnt from experienced professors and practitioners in the community.
Gravitational Lensing by NFW Halos

We investigate the gravitational lensing properties of dark matter halos with Navarro, Frenk & White (NFW) density profiles and derive an analytic expression for the radial dependence of the shear, γ(x), due to these objects. In addition, we derive an expression for the mean shear interior to a given radius, (x), and use this to quantify systematic errors that will arise in weak-lensing mass estimates of astronomical objects in cases where the mass estimate is based on an a priori assumption that the underlying potential is that of a singular isothermal sphere when in fact the potential is that of an NFW-type object. On mass scales of 1011 M☉ M200 1015 M☉, the assumption of an isothermal sphere potential results in an overestimate of the halo mass, and the amount by which the mass is overestimated increases linearly with the value of the NFW concentration parameter. Considerable overestimates of the mass (~60%) can occur for galaxy-sized halos, but for rich clusters the mass overestimate is small. The degree to which the mass is systematically in error depends on the cosmology adopted, with a COBE-normalized standard cold dark matter (CDM) model yielding the largest systematic errors for a given true value of the halo mass.
Model-Based Processing of Microcantilever Sensor Arrays

In this paper, we have developed a model-based processor (MBP) for a microcantilever-array sensor to detect target species in solution. We perform a proof-of-concept experiment, fit model parameters to the measured data and use them to develop a Gauss-Markov simulation. We then investigate two cases of interest, averaged deflection data and multichannel data. For this evaluation we extract model parameters via a model-based estimation, perform a Gauss-Markov simulation, design the optimal MBP and apply it to measured experimental data. The performance of the MBP in the multichannel case is evaluated by comparison to a "smoother" (averager) typically used for microcantilever signal analysis. It is shown that the MBP not only provides a significant gain (~80 dB) in signal-to-noise ratio (SNR), but also consistently outperforms the smoother by 40-60 dB. Finally, we apply the processor to the smoothed experimental data and demonstrate its capability for chemical detection. The MBP performs quite well, apart from a correctable systematic bias error
Reactions in the conjugated ‘ene–ene–yne’ manifold: five-membered ring fragmentation and ring formation via coarctate/pseudocoarctate mechanisms

The fragmentation of a 5-membered heteroaromatic ring to afford a conjugated ene–ene–yne skeleton, and the corresponding reverse process, cyclization of the hetero-ene–ene–yne motif to generate a variety of heterocyclic systems, are the subject of this review. These synthetically useful reactions, which proceed through a coarctate/pseudocoarctate mechanistic pathway, are unique in that they involve the generation of either a carbene or nitrene intermediate, and provide access to hard to obtain heterocyclic or ene–ene–yne structures. While fragmentation of heteroaromatic rings containing a exocyclic carbene or nitrene has been well documented in the literature for over 40 years, the use of hetero-ene–ene–yne precursors to synthesize heterocycles is a relatively new approach that is generating much interest in the literature. This review highlights both the synthetic and mechanistic aspects of these unique reactions.
Fault-Tolerant Control of Nonlinear Processes: Performance-Based Reconfiguration and Robustness

This work considers the problem of control system/actuator failures in nonlinear processes subject to input constraints and presents two approaches for fault-tolerant control that focus on incorporating performance and robustness considerations, respectively. In both approaches, first a family of candidate control configurations, characterized by different manipulated inputs, is identified for the process under consideration. Performance considerations are first incorporated via the design of a Lyapunov-based predictive controller that enforces closed-loop stability from an explicitly characterized set of initial conditions (computed using an auxiliary Lyapunov-based nonlinear controller). A hierarchical switching policy is derived, that uses stability considerations (evaluated via the presence of the state in the stability region of a control configuration) to ascertain the suitability of a candidate backup configuration and then performance considerations are again considered in choosing between the suitable backup configurations. Next, we consider the problem of implementing fault-tolerant control to nonlinear processes subject to input constraints and uncertainty. To this end, we first design a robust hybrid predictive controller for each candidate control configuration that guarantees stability from an explicitly characterized set of initial conditions, subject to uncertainty and constraints. A switching policy is then derived to orchestrate the activation/deactivation of the constituent control configurations
Ultrafast laser generation of hard X-rays

Efficient generation of X-rays above 20 keV was demonstrated when the tight focus of a 60-mJ, 120-fs laser was incident on a solid. It is estimated that 0.3% of the laser energy is converted to X-rays between 20 and 1000 keV when the target is solid tantalum. At least 10/sup 6/ photons above 1 MeV are generated with each shot. The X-ray yield is proportional to the Z of the target, and scales as the 3/2 power of the incident laser energy. >
Linearly homomorphic signatures over binary fields and new tools for lattice-based signatures

We propose a linearly homomorphic signature scheme that authenticates vector subspaces of a given ambient space. Our system has several novel properties not found in previous proposals: • It is the first such scheme that authenticates vectors defined over binary fields; previous proposals could only authenticate vectors with large or growing coefficients. • It is the first such scheme based on the problem of finding short vectors in integer lattices, and thus enjoys the worst-case security guarantees common to lattice-based cryptosystems. Our scheme can be used to authenticate linear transformations of signed data, such as those arising when computing mean and Fourier transform or in networks that use network coding. Our construction gives an example of a cryptographic primitive -- homomorphic signatures over F2 -- that can be built using lattice methods, but cannot currently be built using bilinear maps or other traditional algebraic methods based on factoring or discrete log type problems. Security of our scheme (in the random oracle model) is based on a new hard problem on lattices, called k-SIS, that reduces to standard average-case and worst-case lattice problems. Our formulation of the k-SIS problem adds to the "toolbox" of lattice-based cryptography and may be useful in constructing other lattice-based cryptosystems. As a second application of the new k-SIS tool, we construct an ordinary signature scheme and prove it k-time unforgeable in the standard model assuming the hardness of the k-SIS problem. Our construction can be viewed as "removing the random oracle" from the signatures of Gentry, Peikert, and Vaikuntanathan at the expense of only allowing a small number of signatures.
An Assessment of Recent Changes in the Uniform Accountancy Act

The Uniform Accountancy Act (UAA) is the product of a joint effort by the American Institute of Certified Public Accountants and the National Association of State Boards of Accountancy. It is intended to serve as a model for public accountancy legislation by the individual states, and is designed to protect the public interest, promote high professional standards, and advance the goal of uniformity across jurisdictions. In response to growing dissatisfaction with the current status of professional accountancy regulation, the UAA was substantially revised in 1998. Based on existing rationales for governmental involvement in occupational licensing, we assess whether selected changes reflected in the revised UAA are consistent with its stated public interest objective. We conclude that many, but not all, of these changes are in the public interest. Based on an economic theory of regulation, the paper also examines the likelihood that the states will adopt the proposed changes. Because the CPA profession is w...
Density functional theory for transition metals and transition metal chemistry

We introduce density functional theory and review recent progress in its application to transition metal chemistry. Topics covered include local, meta, hybrid, hybrid meta, and range-separated functionals, band theory, software, validation tests, and applications to spin states, magnetic exchange coupling, spectra, structure, reactivity, and catalysis, including molecules, clusters, nanoparticles, surfaces, and solids.
REMOD: a new methodology for designing fault-tolerant arithmetic circuits

REMOD (REprocessing with MicrO Delays) is a new method for fault-tolerant design of logic circuits composed of arrays of identical functional cells. The fault detection scheme is based on the principle of node covering, in which the computation of each cell is checked by a "covering" cell. After a faulty cell is detected, the node covering principle also allows the circuit to easily be reconfigured to perform correctly for subsequent inputs. Furthermore, the design method is extendable to multiple fault tolerance with only small increments of hardware and time. We have laid out and simulated REMOD-based circuits for adders and multipliers and show that the time overheads are a small factor of the original computation time-0 or /spl Theta/(1/n) to /spl Theta/(1/(log n)), for an n-cell circuit. For moderately complex cells, it is seen that area overhead is very reasonable as well.
A Consensus Tree Approach for Reconstructing Human Evolutionary History and Detecting Population Substructure

The random accumulation of variations in the human genome over time implicitly encodes a history of how human populations have arisen, dispersed, and intermixed since we emerged as a species. Reconstructing that history is a challenging computational and statistical problem but has important applications both to basic research and to the discovery of genotype-phenotype correlations. We present a novel approach to inferring human evolutionary history from genetic variation data. We use the idea of consensus trees, a technique generally used to reconcile species trees from divergent gene trees, adapting it to the problem of finding robust relationships within a set of intraspecies phylogenies derived from local regions of the genome. Validation on both simulated and real data shows the method to be effective in recapitulating known true structure of the data closely matching our best current understanding of human evolutionary history. Additional comparison with results of leading methods for the problem of population substructure assignment verifies that our method provides comparable accuracy in identifying meaningful population subgroups in addition to inferring relationships among them. The consensus tree approach thus provides a promising new model for the robust inference of substructure and ancestry from large-scale genetic variation data.
Y (4260) and Y (4360) as mixed hadrocharmonium

Recent BESIII data indicate a significant rate of the process e+e- →hc π+ π- at the Y(4260) and Y(4360) resonances, implying a substantial breaking of the heavy quark spin symmetry. We consider these resonances within the picture of hadrocharmonium, i.e. of (relatively) compact charmonium embedded in a light-quark mesonic excitation. We suggest that the resonances Y(4260) and Y(4360) are a mixture, with mixing close to maximal, of two states of hadrochamonium, one containing a spin-triplet $c \bar c$ pair and the other containing a spin-singlet heavy quark pair. We argue that this model is in a reasonable agreement with the available data and produces distinctive and verifiable predictions for the energy dependence of the production rate in e+e- annihilation of the final states J/ψππ, ψ′ππ and hc ππ, including the pattern of interference between the two resonances.
Control store implementation of a high performance VLSI CISC

The implementation of the m-sequencer and the large loadable control store of a high performance CMOS 370 system [1] is described. The control store consists of two parts, a small on-chip control store and a main control store. A small on-chip control store keeps the first two control words of each m-sequence. A large main control store contains the remaining control words of each m-sequence. The small control store is implemented so that there is no need to include an extra pipeline stage to start an instruction execution in order to achieve a short cycle time. With a short cycle time, the access of the large control store takes at least two cycles to complete. In order to get one control word every cycle, the access to the control store is pipelined. A static m-branch prediction scheme is used to generate the next m-address ahead of the determination of a m-branch. With this scheme, an effectively one-cycle access from a large loadable control store can be achieved without affecting the machine cycle time.
Cumulative Harm, Products Liability, and Bilateral Care

We extend consideration of cumulative harm in products liability to the case of bilateral care. For this specification, the level of care and the level of output chosen by the firm are inextricably interrelated, and different liability regimes yield different combinations of care and output. As in the case of bilateral care with proportional harm, strict liability by itself leads to moral hazard on the part of the consumer, but strict liability with a defense of contributory negligence on the part of the consumer is now a resilient (that is, both robust and convergent) liability rule when harm is cumulative.
YET ANOTHER TALE OF TWO CITIES: BUENOS AIRES AND CHICAGO

Buenos Aires and Chicago grew during the nineteenth century for remarkably similar reasons. Both cities were conduits for moving meat and grain from fertile hinterlands to eastern markets. However, despite their initial similarities, Chicago was vastly more prosperous for most of the twentieth century. Can the differences between the cities after 1930 be explained by differences in the cities before that date? We highlight four major differences between Buenos Aires and Chicago in 1914. Chicago was slightly richer, and significantly better educated. Chicago was more industrially developed, with about 2.25 times more capital per worker. Finally, Chicago’s political situation was far more stable and it was not a political capital. Human capital seems to explain the lion’s share of the divergent path of the two cities and their countries, both because of its direct effect and because of the connection between education and political instability.
Monolithic millimeter-wave IMPATT oscillator and active antenna

A monolithic IMPATT fabrication technique was developed to integrate active devices and radiating elements on the same surface of a semi-insulating GaAs substrate. Since the IMPATT diode resonator also acted as the radiating element, the oscillator was automatically matched to the antenna properties, eliminating antenna feed mismatch losses. Devices operating at 43.3 GHz produced 26 mW CW output power with 7.1% conversion efficiency. The oscillation frequency and the radiation patterns were determined by the properties of the on-chip circuitry. This monolithic oscillator was also coupled to waveguide using several configurations. Low-cost oscillator fabrication was demonstrated; linear arrays of such radiating elements were produced and radiation patterns were determined as a function of interelement spacings and element numbers. >
Regulatory Actions under Adjustment Costs and the Resolution of Scientific Uncertainty

Food system regulators often decide whether to ban existing practices or approve new technologies without conclusive scientific evidence on possible damage and knowing that resolution is likely in the future. In a model with three decision points and stochastic resolution of uncertainty, we study interactions between expected losses due to regulation and information availability when a regulator is deciding on an early reversible ban and on a later reversible ban. Adjustment costs create inertia concerning intermediate signals such that earlier decisions are not overturned, and also a bias against imposing an early ban. The prospect of more later-stage information can increase or decrease the incentive to ban early, but research decreases the incentive to ban early.
Einstein metrics on spheres

We prove the existence of an abundance of new Einstein metrics on odd dimensional spheres including exotic spheres, many of them depending on continuous parameters. The number of families as well as the number of parameter grows double exponentially with the dimension. Our method of proof uses Brieskorn-Pham singularities to realize spheres (and exotic spheres) as circle orbi-bundles over complex algebraic orbifolds, and lift a Kaehler-Einstein metric from the orbifold to a Sasakian-Einstein metric on the sphere.
Commutativity-based concurrency control for abstract data types

Two novel concurrency control algorithms for abstract data types are presented. The algorithms ensure serializability of transactions by using conflict relations based on the commutativity of operations. It is proved that both algorithms ensure a local atomicity property called dynamic atomicity. This means that the algorithms can be used in combination with any other algorithms that also ensure dynamic atomicity. The algorithms are quite general, permitting operations to be both partial and nondeterministic., They permit the results returned by operations to be used in determining conflicts, thus permitting higher levels of concurrency than is otherwise possible. The descriptions and proofs encompass recovery as well as concurrency control. The two algorithms use different recovery methods: one uses intentions lists, and the other uses undo logs. It is shown that conflict relations that work with one recovery method do not necessarily work with the other. A general correctness condition that must be satisfied by the combination of a recovery method and a conflict relation is identified. >
Gold-catalyzed intramolecular aminoarylation of alkenes: C-C bond formation through bimolecular reductive elimination.

Gold-ilocks and the 3 mol % catalyst: Bimetallic gold bromides allow the room temperature aminoarylation of unactivated terminal olefins with aryl boronic acids using Selectfluor as an oxidant. A catalytic cycle involving gold(I)/gold(III) and a bimolecular reductive elimination for the key CC bond-forming step is proposed. dppm= bis(diphenylphosphanyl)methane.
Tight Approximations of Dynamic Risk Measures

This paper compares two frameworks for measuring risk in a multiperiod setting. The first corresponds to applying a single coherent risk measure to the cumulative future costs, and the second involves applying a composition of one-step coherent risk mappings. We characterize several necessary and sufficient conditions under which one measurement always dominates the other and introduce a metric to quantify how close the two measures are. Using this notion, we address the question of how tightly a given coherent measure can be approximated by lower or upper bounding compositional measures. We exhibit an interesting asymmetry between the two cases: the tightest upper bound can be exactly characterized and corresponds to a popular construction in the literature, whereas the tightest lower bound is not readily available. We show that testing domination and computing the approximation factors are generally NP-hard, even when the risk measures are comonotonic and law-invariant. However, we characterize conditio...
Food, Technology and Hunger

This article uses genetically modified crops as a springboard for examining the role ascribed to technology by the international institutional framework for responding to food insecurity. It argues that food insecurity is a problem rooted in political will formation rather than in the mechanics of food production. From this starting point, the article examines the failure of various global initiatives to end hunger, highlighting how these initiatives emphasized new technologies for increasing food production while giving short shrift to the thorny structural problems associated with hunger.
AVIA: an interactive web-server for annotation, visualization and impact analysis of genomic variations

Motivation: The plethora of information that emerges from large-scale genome characterization studies has triggered the development of computational frameworks and tools for efficient analysis, interpretation and visualization of genomic data. Functional annotation of genomic variations and the ability to visualize the data in the context of whole genome and/or multiple genomes has remained a challenging task. We have developed an interactive web-based tool, AVIA (Annotation, Visualization and Impact Analysis), to explore and interpret large sets of genomic variations (single nucleotide variations and insertion/deletions) and to help guide and summarize genomic experiments. The annotation, summary plots and tables are packaged and can be downloaded by the user from the email link provided. Availability and implementation: http://avia.abcc.ncifcrf.gov. Contact: vog.hin.liam@mhgnouv Supplementary information: Supplementary data are available at Bioinformatics online.