cssi/SciSciGPT-SciSciNet huggingface dataset:
The effect of number of Hamiltonian paths on the complexity of a vertex-coloring problem

A generalization of Dobkin and Lipton’s element uniqueness problem is introduced. For any fixed undirected graph G on vertex set $\{ v _1 , v_2 , \cdots , v_n \} $, the problem is to determine, given n real numbers $x_1 ,x_2 , \cdots ,x_n $, whether $x_i \ne x_j $ for every edge $\{ \upsilon _i ,\upsilon _j \} $ in G. This problem is shown to have upper and lower bounds of $\Theta (n\log n)$ linear comparisons if G is any dense graph. The proof of the lower bound involves showing that any dense graph must contain a subgraph with many Hamiltonian paths, and demonstrating the relevance of these Hamiltonian paths to a geometric argument. In addition, we exhibit relatively sparse graphs for which the same lower bound holds, and relatively dense graphs for which a linear upper bound holds.
Exercise-Induced Urinary and Fecal Incontinence: An Exceedingly Unusual Presentation of Aortoiliac Occlusive Disease: A Case Report

Fecal and urinary incontinence is an exceedingly unusual manifestation of aortoiliac occlusive disease, with only 4 previous cases having been reported in the literature. The authors report the cas...
Shocks and cold fronts in galaxy clusters

Abstract The currently operating X-ray imaging observatories provide us with an exquisitely detailed view of the Megaparsec-scale plasma atmospheres in nearby galaxy clusters. At z 0.05 , the Chandra's 1 ″ angular resolution corresponds to linear resolution of less than a kiloparsec, which is smaller than some interesting linear scales in the intracluster plasma. This enables us to study the previously unseen hydrodynamic phenomena in clusters: classic bow shocks driven by the infalling subclusters, and the unanticipated “cold fronts,” or sharp contact discontinuities between regions of gas with different entropies. The ubiquitous cold fronts are found in mergers as well as around the central density peaks in “relaxed” clusters. They are caused by motion of cool, dense gas clouds in the ambient higher-entropy gas. These clouds are either remnants of the infalling subclusters, or the displaced gas from the cluster's own cool cores. Both shock fronts and cold fronts provide novel tools to study the intracluster plasma on microscopic and cluster-wide scales, where the dark matter gravity, thermal pressure, magnetic fields, and ultrarelativistic particles are at play. In particular, these discontinuities provide the only way to measure the gas bulk velocities in the plane of the sky. The observed temperature jumps at cold fronts require that thermal conduction across the fronts is strongly suppressed. Furthermore, the width of the density jump in the best-studied cold front is smaller than the Coulomb mean free path for the plasma particles. These findings show that transport processes in the intracluster plasma can easily be suppressed. Cold fronts also appear less prone to hydrodynamic instabilities than expected, hinting at the formation of a parallel magnetic field layer via magnetic draping. This may make it difficult to mix different gas phases during a merger. A sharp electron temperature jump across the best-studied shock front has shown that the electron–proton equilibration timescale is much shorter than the collisional timescale; a faster mechanism has to be present. To our knowledge, this test is the first of its kind for any astrophysical plasma. We attempt a systematic review of these and other results obtained so far (experimental and numerical), and mention some avenues for further studies.
Synthetic applications of gilman reagents derived from 2-bromo-2-cycloalken-1-one Ethylene Ketals

Abstract Gilman reagents derived from 2-bromo-2-cycloalken-1-one ethylene ketals react with allylic, propargylic or benzylic halides to produce functionalized 1,4-dienes while reaction with Michael acceptors gives 1,4-adducts.
Numerical anisotropy in finite differencing

Numerical solutions to hyperbolic partial differential equations, involving wave propagations in one direction, are subject to several specific errors, such as numerical dispersion, dissipation or aliasing. In the multi-dimensional case, where the waves propagate in all directions, there is an additional specific error resulting from the discretization of spatial derivatives along the grid lines. Specifically, waves or wave packets in the multi-dimensional case propagate at different phase or group velocities, respectively, along different directions. A commonly used term for the aforementioned multi-dimensional discretization error is the numerical anisotropy or isotropy error. In this review, the numerical anisotropy is briefly described in the context of the wave equation in the multi-dimensional case. Then several important studies that were focused on optimizations of finite difference schemes with the objective of reducing the numerical anisotropy are discussed.
Hilbert Modular Forms with Prescribed Ramification

Let K be a totally real field. We present an asymptotic formula for the number of Hilbert modular cusp forms f with given ramification at every place v of K. When v is an infinite place, this means specifying the weight of f at k, and when v is finite, this means specifying the restriction to inertia of the local Weil-Deligne representation attached to f at v. Our formula shows that with essentially finitely many exceptions, the cusp forms of K exhibit every possible sort of ramification behavior.
Transfer College Quality and Student Performance

We examine how students who transfer credit for an introductory-level course from schools of varying quality perform in a subsequent intermediate-level course, holding constant many student characteristics. We measure college quality by the percent of students admitted, the student faculty ratio, listed tuition, the percentage of professors with Ph.D.s, and SAT scores. Students taking introductory courses at higher quality institutions earn higher grades in their intermediate courses than students transferring from lower quality institutions. A back-of-the-envelope calculation suggests that, for the average student, the benefit from attending a higher quality institution is more than worth the higher tuition.
Context-free-grammar based token tagger in reconfigurable devices

We present a high performance reconfigurable hardware architecture for detecting patterns as well as their contextual meaning. By analyzing for both semantic content and structure, the accuracy of content-level processing systems can be improved. Our system is built using semantics defined by context-free-grammar (CFG) to tag the streaming data. Unlike the traditional table look up and stack based engines used in CFG parsers, we explore a new method that maps the grammar structure on to the Field Programmable Gate Arrays (FPGA) hardware. The structure is a direct translation of the grammar which enables the meaning of the patterns to be determined based on the location of its detection. The parallel pattern detection engines are instantiated using FPGA resources. Our implementation scans for the regular expression patterns and determines their semantics as defined by a grammar. This highly parallel and fine grained pipelined engine with 8 bit input bus can operate in bandwidth above 2 Gbps. For a simple XML grammar example, our engine can detect and tag the patterns at 1.57 Gbps on Xilinx VirtexE FPGA and 4.26 Gbps on the new Virtex 4 devices.
The Spectrum of Mutations Causing HPRT Deficiency: An Update

Mutations in the gene encoding hypoxanthine‐guanine phosphoribosyltransferase (HPRT) cause Lesch–Nyhan disease, which is characterized by hyperuricemia, severe motor disability, and self‐injurious behavior. Mutations in the same gene also cause less severe clinical phenotypes with only some portions of the full syndrome. A large database of 271 mutations associated with both full and partial clinical phenotypes was recently compiled. Since the original database was assembled, 31 additional mutations have been identified, bringing the new total to 302. The results demonstrate a very heterogeneous collection of mutations for both LND and its partial syndromes. The differences between LND and the partial phenotypes cannot be explained by differences in the locations of mutations, but the partial phenotypes are more likely to have mutations predicted to allow some residual enzyme function. The reasons for some apparent exceptions to this proposal are addressed.
Studies on the chemical nature of the substance inducing transformation of Pneumococcal types

Oswald T. Avery, Colin M. MacLeod, Maclyn McCarty: Studies on the Chemical Nature of the Substance Inducing Transformation of Pneumococcal Types
Observation of Hydrofluoric Acid Burns on Osseous Tissues by Means of Terahertz Spectroscopic Imaging

Terahertz technologies have gained great amount of attention for biomedical imaging and tissue analysis. In this study, we utilize terahertz imaging to study the effects of hydrofluoric acid on both compact bone tissue and cartilage. We compare the differences observed in the exposure for formalin fixed and raw, dried, tissue as well as those resulting from a change in hydrofluoric (HF) concentration. Measurements are performed with THz-TDS, and a variety of spectroscopic-based image reconstruction techniques are utilized to develop contrast in the features of interest.
Min-max variational principle and front speeds in random shear flows

Speed ensemble of bistable (combustion) fronts in mean zero stationary Gaussian shear flows inside two and three dimensional channels is studied with a min-max variational principle. In the small root mean square regime of shear flows, a new class of multi-scale test functions are found to yield speed asymptotics. The quadratic speed enhancement law holds with probability arbitrarily close to one under the almost sure continuity (dimension two) and mean square Holder regularity (dimension three) of the shear flows. Remarks are made on the conditions for the linear growth of front speed expectation in the large root mean square regime. Department of Mathematics, University of Texas at Austin, Austin, TX 78712 (jnolen@math.utexas.edu). Department of Mathematics and ICES (Institute of Computational Engineering and Sciences), University of Texas at Austin, Austin, TX 78712 (jxin@math.utexas.edu).
Fundamental Physical Parameters of Collimated Gamma-Ray Burst Afterglows

We determine the basic physical characteristics of eight gamma-ray bursts (GRBs)—980519, 990123, 990510, 991208, 991216, 000301c, 000926, and 010222—by modeling the broadband emission of their afterglows. We find that the burst kinetic energies after the GRB phase are well clustered around a mean value of 3 × 1050 ergs. In contrast, the energy release in gamma rays, after correcting for a collimated explosion, varies among bursts by more than an order of magnitude. The initial jet apertures are in the 2°-14° range, mildly correlated with the energy, with half of the jets being narrower than ~3°. This implies that, within 100 Mpc, there are about 10 GRB remnants (expanding at ~0.1c) that can be resolved with the Very Long Baseline Array. For all eight afterglows, the total energy in the shock-accelerated electrons is close to the equipartition with protons. However, the slope of the power-law electron distribution is not universal, varying between 1.4 and 2.8. In at least half of the cases, the density structure of the medium is inconsistent with an r-2 profile. A homogeneous medium with density in the 0.1-50 cm-3 range can accommodate the broadband emission of all afterglows, with the exception of 990123, for which we find the density to be less than 10-2 cm-3. If GRBs arise from the core collapse of massive stars, then such low densities indicate the existence of superbubbles created by the supernovae and winds within a cluster of massive stars.
Implementing risk management systems with a benchmark: a Web-Based DSS approach

Traditional capital budgeting models price only systemic risk. However, insurers and banks seek to manage their total risk. With the help of modern information systems and information technology, bankers and insurers are able to get timely information on the risk exposures of their multiple lines of business. This paper presents the framework of a Web-Based Decision Support System (WBDSS) and illustrates how the proposed system may effectively support the use, in a firm's risk management IT infrastructure, of models that price total risk. Expectation pricing model is used as an example to show how the proposed system may help insurers and banks to perform total risk management.
Sinorhizobium meliloti Requires a Cobalamin-Dependent Ribonucleotide Reductase for Symbiosis With Its Plant Host

Vitamin B12 (cobalamin) is a critical cofactor for animals and protists, yet its biosynthesis is limited to prokaryotes. We previously showed that the symbiotic nitrogen-fixing alphaproteobacterium Sinorhizobium meliloti requires cobalamin to establish a symbiotic relationship with its plant host, Medicago sativa (alfalfa). Here, the specific requirement for cobalamin in the S. meliloti–alfalfa symbiosis was investigated. Of the three known cobalamin-dependent enzymes in S. meliloti, the methylmalonyl CoA mutase (BhbA) does not affect symbiosis, whereas disruption of the metH gene encoding the cobalamin-dependent methionine synthase causes a significant defect in symbiosis. Expression of the cobalamin-independent methionine synthase MetE alleviates this symbiotic defect, indicating that the requirement for methionine synthesis does not reflect a need for the cobalamin-dependent enzyme. To investigate the function of the cobalamin-dependent ribonucleotide reductase (RNR) encoded by nrdJ, S. meliloti was en...
Efficiency improvement of grid-tied inverters at low input power using pulse skipping control strategy

Pulse skipping control strategy is applied to improve efficiency of grid-tied inverter at light load. To maximize the efficiency of pulse skipping operation mode, three key parameters are identified and can be optimized based on a loss model, which is developed to find the maximal efficiency points using three-dimension searching technique. To reduce the potential of pulsating on the power grid, the synchronization of the power pulse to the grid is addressed by varying the DC bus voltage window, namely varying the upper and lower DC voltage limits. A 200W prototype is setup to verify the proposed strategy. The experimental results show that the proposed strategy greatly improves the efficiency at light load and match the simulation results fairly well, thus verifying the validity of the proposed optimization method for pulse skipping.
Graph-shifts: Natural image labeling by dynamic hierarchical computing

In this paper, we present a new approach for image labeling based on the recently introduced graph-shifts algorithm. Graph-shifts is an energy minimization algorithm that does labeling by dynamically manipulating, or shifting, the parent-child relationships in a hierarchical decomposition of the image. Each shift optimally reduces the energy by indirectly causing a change to the labeling; graph-shifts is able to rapidly compute and select this optimal shift at every iteration. There are no constraints on the terms of the (pairwise) energy function. The algorithm was originally presented in the context of medical image labeling using conditional random field models. In this paper, we consider the algorithm in the context of both low- and high-level natural image labeling. We show that for examples in both classes of problems, graph-shifts does labeling both accurately and rapidly. For low-level vision, we explore image restoration, and for high-level vision, we make use of a hybrid discriminative-generative model to segment and label images into semantically meaningful regions (e.g., trees, buildings, etc.). For both problems, we obtain comparable or superior results to the state-of-the-art computed in just a few seconds per image.
Polynomials that Sign Represent Parity and Descartes' Rule of Signs

A real polynomial P(X 1, ... , X n ) sign represents f : A n ? {0, 1} if for every (a 1, ... , a n ) ? A n , the sign of P(a 1, ... ,a n ) equals $$(-1)^{f(a_{1}, \ldots ,a_{n})}$$ . Such sign representations are well-studied in computer science and have applications to computational complexity and computational learning theory. The work in this area aims to determine the minimum degree and sparsity possible for a polynomial that sign represents a function f. While the degree of such polynomials is relatively well-understood, far less is known about their sparsity. Known bounds apply only to the cases where A = {0, 1} or A = {?1, +1}. In this work, we present a systematic study of tradeoffs between degree and sparsity of sign representations through the lens of the parity function. We attempt to prove bounds that hold for any choice of set A. We show that sign representing parity over {0,... , m ? 1} n with the degree in each variable at most m ? 1 requires sparsity at least m n . We show that a tradeoff exists between sparsity and degree, by exhibiting a sign representation that has higher degree but lower sparsity. We show a lower bound of n(m ? 2) + 1 on the sparsity of polynomials of any degree representing parity over {0,... ,m ? 1} n . We prove exact bounds on the sparsity of such polynomials for any two element subset A. The main tool used is Descartes' Rule of Signs, a classical result in algebra, relating the sparsity of a polynomial to its number of real roots. As an application, we use bounds on sparsity to derive circuit lower bounds for depth-two AND-OR-NOT circuits with a Threshold Gate at the top.
Maximum Margin Algorithms with Boolean Kernels

Recent work has introduced Boolean kernels with which one can learn linear threshold functions over a feature space containing all conjunctions of length up to k (for any 1 ≤ k ≤ n) over the original n Boolean features in the input space. This motivates the question of whether maximum margin algorithms such as Support Vector Machines can learn Disjunctive Normal Form expressions in the Probably Approximately Correct (PAC) learning model by using this kernel. We study this question, as well as a variant in which structural risk minimization (SRM) is performed where the class hierarchy is taken over the length of conjunctions.We show that maximum margin algorithms using the Boolean kernels do not PAC learn t(n)-term DNF for any t(n) = ω(1), even when used with such a SRM scheme. We also consider PAC learning under the uniform distribution and show that if the kernel uses conjunctions of length ˜ω(√n) then the maximum margin hypothesis will fail on the uniform distribution as well. Our results concretely illustrate that margin based algorithms may overfit when learning simple target functions with natural kernels.
Relative Goods' Prices, Pure Inflation, and the Phillips Correlation

This paper uses a dynamic factor model for the quarterly changes in consumption goods’ prices to separate them into three independent components: idiosyncratic relative-price changes, a low-dimensional index of aggregate relative-price changes, and an index of equiproportional changes in all inflation rates, that we label “pure” inflation. The paper estimates the model on U.S. data since 1959, and it presents a simple structural model that relates the three components of price changes to fundamental economic shocks. We use the estimates of the pure inflation and aggregate relative-price components to answer two questions. First, what share of the variability of inflation is associated with each component, and how are they related to conventional measures of monetary policy and relative-price shocks? We find that pure inflation accounts for 15-20% of the variability in inflation while our aggregate relative-price index accounts most of the rest. Conventional measures of relative prices are strongly but far from perfectly correlated with our relative-price index; pure inflation is only weakly correlated with money growth rates, but more strongly correlated with nominal interest rates. Second, what drives the Phillips correlation between inflation and measures of real activity? We find that the Phillips correlation essentially disappears once we control for goods’ relative-price changes. This supports modern theories of inflation dynamics based on price rigidities and many consumption goods.
HOW COSTLY IS HOSPITAL QUALITY? A REVEALED-PREFERENCE APPROACH

We analyze the cost of quality improvement in hospitals, dealing with two challenges. Hospital quality is multidimensional and hard to measure, while unobserved productivity may influence quality supply. We infer the quality of hospitals in Los Angeles from patient choices. We then incorporate ‘revealed quality’ into a cost function, instrumenting with hospital demand. We find that revealed quality differentiates hospitals, but is not strongly correlated with clinical quality. Revealed quality is quite costly, and tends to increase with hospital productivity. Thus, non-clinical aspects of the hospital experience (perhaps including patient amenities) play important roles in hospital demand, competition, and costs.
What is a public health "emergency"?

In March, Governor Deval Patrick declared the Massachusetts opioid-addiction epidemic a public health emergency, a move that allows governors and health officials to take extraordinary legal action. This unusual invocation of emergency powers raises important questions.
XMM-Newton Spectra of Intermediate-Mass Black Hole Candidates: Application of a Monte Carlo Simulated Model

We present a systematic spectral analysis of six ultraluminous X-ray sources (NGC 1313 X-1 and X-2, IC 342 X-1, Ho IX X-1, NGC 5408 X-1, and NGC 3628 X-1) observed with the XMM-Newton observatory. These extranuclear X-ray sources in nearby late-type galaxies have been considered as intermediate-mass black hole candidates. We have performed Monte Carlo simulations of Comptonized multicolor blackbody accretion disks. This unified and self-consistent spectral model assumes a spherically symmetric, thermal corona around each disk and accounts for the radiation transfer in the Comptonization. We find that the model provides satisfactory fits to the XMM-Newton spectra of the sources. The characteristic temperatures of the accretion disks (Tin), for example, are in the range of ~0.05-0.3 keV, consistent with the intermediate-mass black hole interpretation. We find that the black hole mass is typically about a few times 103 M☉ and has an accretion rate of ~10-6 to 10-5 M☉ yr-1. For the spectra considered here, we find that the commonly used multicolor blackbody accretion disk model with an additive power-law component, although not physical, provides a good mathematical approximation to the Monte Carlo simulated model. However, the latter model provides additional constraints on the properties of the accretion systems, such as the disk inclination angles and corona optical depths.
Scattering from a periodic array of apertures or plates where the conductors have arbitrary shape, thickness, and resistivity

The scattering properties of a periodic array of conductors having any shape composed of steps along the coordinate axes and illuminated by a plane wave are obtained through a rooftop current approximation. The solution, which involves a finite dimension matrix equation, is described along with an algorithm that efficiently generates the matrix elements. Results presented for arrays of rectangular apertures and thin, rectangular plates are shown to agree closely with those obtained through standard modal approaches. Convergence with respect to the number of current elements is also explored. Because the normal component of the edge current is nonzero and continuous when thickness is present, convergence is significantly better than for zero-thickness structures. At glancing incidence, however, accuracy requires a finer subsection grid to properly represent the circulating current on the sidewalls, for plates, and the U-shaped current flowing near the corner of the sidewalls, for apertures.
Results on identified hadrons from the PHENIX experiment at RHIC

Abstract Recent results on identified hadrons from the PHENIX experiment in Au+Au collisions at mid-rapidity at S N N = 200 GeV are presented. The centrality dependence of transverse momentum distributions and particle ratios for identified charged hadrons are studied. The transverse flow velocity and freeze-out temperature are extracted from p T spectra within the framework of a hydrodynamic collective flow model. Two-particle HBT correlations for charged pions are measured in different centrality selections for a broad range of transverse momentum of the pair. Results on elliptic flow measurements with respect to the reaction plane for identified particles are also presented.
Optimal two-value zero-mean disintegration of zero-mean random variables

For any continuous zero-mean random variable $X$, a reciprocating function $r$ is constructed, based only on the distribution of $X$, such that the conditional distribution of $X$ given the (at-most-)two-point set $\{X,r(X)\}$ is the zero-mean distribution on this set; in fact, a more general construction without the continuity assumption is given in this paper, as well as a large variety of other related results, including characterizations of the reciprocating function and modeling distribution asymmetry patterns. The mentioned disintegration of zero-mean r.v.'s implies, in particular, that an arbitrary zero-mean distribution is represented as the mixture of two-point zero-mean distributions; moreover, this mixture representation is most symmetric in a variety of senses. Somewhat similar representations - of any probability distribution as the mixture of two-point distributions with the same skewness coefficient (but possibly with different means) - go back to Kolmogorov; very recently, Aizenman et al. further developed such representations and applied them to (anti-)concentration inequalities for functions of independent random variables and to spectral localization for random Schroedinger operators. One kind of application given in the present paper is to construct certain statistical tests for asymmetry patterns and for location without symmetry conditions. Exact inequalities implying conservative properties of such tests are presented. These developments extend results established earlier by Efron, Eaton, and Pinelis under a symmetry condition.
Synthesis of substituted tetrahydrofuranones and tetrahydropyranones: Photocycloaddition/fragmentation reactions of dioxinones

The combination of dioxinone aldol addition methodology and [2+2]-photocycloaddition/fragmentation reactions can provide access to substituted tetrahydrofuran-3-ones and tetrahydropyran-4-ones, subunits abundantly found in biologically active natural products. Intramolecular photocyclization of vinyl and allyl ethers with dioxinones, followed by fragmentation in alkaline MeOH (K2CO3) leads to tetrahydrofuran-3-ones and tetrahydropyran-4-ones, providing a practical route to versatile building blocks for complex molecule synthesis.
Fast and scalable startup of MPI programs in infiniband clusters

One of the major challenges in parallel computing over large scale clusters is fast and scalable process startup, which typically can be divided into two phases: process initiation and connection setup In this paper, we characterize the startup of MPI programs in InfiniBand clusters and identify two startup scalability issues: serialized process initiation in the initiation phase and high communication overhead in the connection setup phase To reduce the connection setup time, we have developed one approach with data reassembly to reduce data volume, and another with a bootstrap channel to parallelize the communication Furthermore, a process management framework, Multi-Purpose Daemons (MPD) system is exploited to speed up process initiation Our experimental results show that job startup time has been improved by more than 4 times for 128-process jobs, and the improvement can be more than two orders of magnitude for 2048-process jobs as suggested by our analytical models.
What Ever Happened to Project Bamboo

This paper charts the origins, trajectory, development, challenges, and conclusion of Project Bamboo, a humanities cyberinfrastructure initiative funded by the Andrew W. Mellon Foundation between 2008 and 2012. Bamboo aimed to enhance arts and humanities research through the development of infrastructure and support for shared technology services. Its planning phase brought together scholars, librarians, and IT staff from a wide range of institutions, in order to gain insight into the scholarly practices Bamboo would support, and to build a community of future developers and users for Bamboo’s technical deliverables. From its inception, Bamboo struggled to define itself clearly and in a way that resonated with scholars, librarians, and IT staff alike. The early emphasis on a serviceoriented architecture approach to supporting humanities research failed to connect with scholars, and the scope of Bamboo’s ambitions expanded to include scholarly networking, sharing ideas and solutions, and demonstrating how digital tools and methodologies can be applied to research questions. Funding constraints for Bamboo’s implementation phase led to the near-elimination of these community-oriented aspects of the project, but the lack of a shared vision that could supersede the individual interests of partner institutions resulted in a scope around which it was difficult to articulate a clear narrative. When Project Bamboo ended in 2012, it had failed to realize its most ambitious goals; this article explores the reasons for this, including technical approaches, communication difficulties, and challenges common to projects that bring together teams from different professional communities.
Effects of systematic uncertainties on the supernova determination of cosmological parameters

Mapping the recent expansion history of the universe offers the best hope for uncovering the characteristics of the dark energy believed to be responsible for the acceleration of the expansion. In determining cosmological and dark-energy parameters to the percent level, systematic uncertainties impose a floor on the accuracy more severe than the statistical measurement precision. We delineate the categorization, simulation, and understanding required to bound systematics for the specific case of the Type Ia supernova method. Using simulated data of forthcoming ground-based surveys and the proposed space-based SNAP mission we present Monte Carlo results for the residual uncertainties on the cosmological parameter determination. The tight systematics control with optical and near-infrared observations and the extended redshift reach allow a space survey to bound the systematics below 0.02 magnitudes at z = 1.7. For a typical SNAP-like supernova survey, this keeps total errors within 15% of the ′ ′ � ,
Fads versus Fundamentals in Farmland Prices

We develop an approach to decompose farmland price time series into three uncorrelated components: permanent fundamental component, temporary fundamental component, and nonfundamental component. This decomposition is useful for studying the importance of fundamental versus nonfundamental factors in explaining farmland price behavior and the dynamic response of farmland prices to shocks to each of these components. The approach is applied to annual Iowa farmland prices over the 1922–94 sample period. We find that fads and overreactions play important roles in explaining short-run price behavior, while long-run price movements are explainable by permanent fundamental shocks.
Analysis of Verification-Based Decoding on the $q$ -ary Symmetric Channel for Large $q$

A new verification-based message-passing decoder for low-density parity-check (LDPC) codes is introduced and analyzed for the q-ary symmetric channel (q-SC). Rather than passing messages consisting of symbol probabilities, this decoder passes lists of possible symbols and marks some lists as verified. The density evolution (DE) equations for this decoder are derived and used to compute decoding thresholds. If the maximum list size is unbounded, then one finds that any capacity-achieving LDPC code for the binary erasure channel can be used to achieve capacity on the q -SC for large q. The decoding thresholds are also computed via DE for the case where each list is truncated to satisfy a maximum list-size constraint. Simulation results are also presented to confirm the DE results. During the simulations, we observed differences between two verification-based decoding algorithms, introduced by Luby and Mitzenmacher, that were implicitly assumed to be identical. In this paper, the node-based algorithms are evaluated via analysis and simulation. The probability of false verification (FV) is also considered and techniques are discussed to mitigate the FV. Optimization of the degree distribution is also used to improve the threshold for a fixed maximum list size. Finally, the proposed algorithm is compared with a variety of other algorithms using both density evolution thresholds and simulation results.
GRADUAL INFLATION OF ACTIVE-REGION CORONAL ARCADES BUILDING UP TO CORONAL MASS EJECTIONS

The pre-coronal mass ejection (pre-CME) structure is of great importance to understanding the origin of CMEs, which, however, has been largely unknown for CMEs originating from active regions. In this paper, we investigate this issue using the wavelet-enhanced EUV Imaging Telescope (EIT) observations combined with the Large Angle and Spectrometric Coronagraph, Michelson Doppler Imager, and GOES soft X-ray observations. Selected for studying are 16 active-region coronal arcades whose gradual inflation lead up to CMEs. Twelve of them clearly build upon post-eruptive arcades resulting from a preceding eruption; the remaining four are located high in the corona in the first place and/or have existed for days. The observed inflation lasts for 8.7 {+-} 4.1 hr, with the arcade rising from 1.15 {+-} 0.06 R{sub sun} to 1.36 {+-} 0.07 R{sub sun} within the EIT field of view (FOV). The rising speed is less than 5 km s{sup -1} most of the time. Only at the end of this quasi-static stage does it increase to tens of kilometers per second over tens of minutes. The arcade then erupts out of the EIT FOV as a CME with similar morphology. This pre-CME structure is apparently unaffected by the flares occurring during its quasi-staticmore » inflation phase, but is closely coupled with the flare occurring during its acceleration phase. For four events that are observed on the disk, it is found that the gradual inflation of the arcade is accompanied by significant helicity injection from the photosphere. In particular, a swirling structure, which is reminiscent of a magnetic flux rope, was observed in one of the arcades over 4 hr prior to the subsequent CME, and the growth of the arcade is associated with the injection of helicity of opposite sign into the active region via flux emergence. We propose a four-phase evolution paradigm for the observed CMEs, i.e., a quasi-static inflation phase which corresponds to the buildup of magnetic free energy in the corona, followed by the frequently observed three-phase paradigm, including an initial phase, an acceleration phase, and a gradual phase.« less
How we think about medication errors: a model and a charge for nurses.

physicians and pharmacists are generally the ones defining practice as it relates to preventing medication errors, without involving nurses. It’s imperative that nurses develop theoretical models, undertake research, and incorporate the findings into practices and processes that improve patient safety. It’s also paramount in the nursing profession that investment be made in both independent and multidisciplinary research. Nurses must investigate why so many medical errors involve medication administration and determine what can be done about it. Research into the state of the science on patient safety presents a relatively uncharted course to nurses. From the nursing perspective, models can be developed that explore medication actions and interactions as well as outcomes. The role of the patient and the nurse‐patient interaction in medication error, such as compliance with discharge instructions, should be investigated as well. Patient-safety research that is directed by nurses would afford opportunities to investigate various age-specific populations, disease states, and medical settings. In the National Quality Forum a number of factors associated with a greater risk of medication errors were identified, any of which would serve as an excellent subject of nursing research, including the impact of diagnostic technologies, patient acuity, and clinical environments on patient safety. 11
The sectional category of a map

We study a generalization of the Svarc genus of a fibre map. For an arbitrary collection ɛ of spaces and a map f : X → Y , we define a numerical invariant, the ɛ-sectional category of f , in terms of open covers of Y . We obtain several basic properties of ɛ-sectional category, including those dealing with homotopy domination and homotopy pushouts. We then give three simple axioms which characterize the ɛ-sectional category. In the final section, we obtain inequalities for the ɛ-sectional category of a composition and inequalities relating the ɛ-sectional category to the Fadell–Husseini category of a map and the Clapp–Puppe category of a map.
User engineering principles for interactive systems

The 'feel' of an interactive system can be compared to the impressions generated by a piece of music. Both can only be experienced over a period of time. With either, the user must abstract the structure of the system from a sequence of details. Each may have a quality of 'naturalness' because successive actions follow a logically self-consistent pattern. Finally, a good composer can write a new pattern which will seem, after a few listenings, to be so natural the observer wonders why it was never done before.
The Deep Structure of Continents.

Gravity and heat flow observations demonstrate that, on the average, mass and radioactivity per unit area are equal under continents and oceans. A global representation of the anomalies in the heat flow and gravity fields shows many similarities, and horizontal gradients in both fields are correlated with earthquake zones. The regional variations of Rayleigh and Love wave velocities provide evidence additional to that of gravity and heat flow that the mantle under continents differs from that under oceans to a depth of 400 to 700 km. Taken together the observations of the planetary fields imply that vertical segregation has been the dominant feature of the process of continent formation. The significance of deep structure of continents and oceans is explored by a number of numerical experiments. The difference in radioactivity between continents and oceans results in a concentration of thermal stresses at the continent-ocean boundary. The ensuing fault zones provide a preferred location for the release of strain energy accumulated by dynamic processes such as those associated with changes in the earth's rotation. The decay of radioactivity implies a past rate of heat production in excess of the heat loss. During the first two to three aeons, the earth expanded at an average rate of about 10 km aeon−1. The resulting fracturing of the outer surface with accompanying upward flow of matter led to the localization of the early continents. Continental growth proceeded by secular differentiation of the subjacent mantle.
Decomposition mechanism and the effects of metal additives on the kinetics of lithium alanate

First-principles density functional theory studies have been carried out for native defects and transition-metal (Ti and Ni) impurities in lithium alanate (LiAlH4), a potential material for hydrogen storage. On the basis of our detailed analysis of the structure, energetics, and migration of lithium-, aluminium-, and hydrogen-related defects, we propose a specific atomistic mechanism for the decomposition and dehydrogenation of LiAlH4 that involves mass transport mediated by native point defects. We also discuss how Ti and Ni impurities alter the Fermi-level position with respect to that in the undoped material, thus changing the concentration of charged defects that are responsible for mass transport. This mechanism provides an explanation for the experimentally observed lowering of the temperature for the onset of decomposition and of the activation energy for hydrogen desorption from LiAlH4.
Gelfand-Graev characters of the finite unitary groups

Gelfand–Graev characters and their degenerate counterparts have an important role in the representation theory of finite groups of Lie type. Using a characteristic map to translate the character theory of the finite unitary groups into the language of symmetric functions, we study degenerate Gelfand–Graev characters of the finite unitary group from a combinatorial point of view. In particular, we give the values of Gelfand–Graev characters at arbitrary elements, recover the decomposition multiplicities of degenerate Gelfand–Graev characters in terms of tableau combinatorics, and conclude with some multiplicity consequences.
Measurement and mitigation of the ionosphere in L-band Interferometric SAR data

Satellite-based repeat-pass Interferometric Synthetic Aperture Radar (InSAR) provides a synoptic high spatial resolution perspective of Earth's changing surface, permitting one to view large areas quickly and efficiently. By measuring relative phase change from one observation to the next on a pixel-by-pixel basis, maps of deformation and change can be derived. Variability of the atmosphere and the ionosphere leads to phase/time delays that are present in the data that can mask many of the subtle deformation signatures of interest, so methods for mitigation of these effects are important. Many of these effects have been observed in existing ALOS PALSAR data [1], and studies are underway to characterize and mitigate the ionosphere using these data. Since the ionosphere is a dispersive medium, it is possible in principle distinguish the ionospheric signatures from the non-dispersive effects of deformation and the atmosphere. In this paper, we describe a method for mapping the ionosphere in InSAR data based on a multi-frequency split-spectrum processing technique. We examine a number of PALSAR data sets, including fully polarimetric and single-polarization 28 MHz bandwidth data, where anomalous effects in phase, amplitude and image registration have been observed. We demonstrate the estimation of the ionosphere by means of the split spectrum technique for estimating differential TEC, whereby a radar waveform is transmitted over the full PALSAR spectral band and widely separated portions of the receive spectrum are processed independently and compared for dispersive effects, and quantify its performance.
Constrained controllability of linear impulse differential systems

Considers the following linear impulse differential control system x/spl dot/=A(t)x, t/spl ne/t/sub k/; /spl Delta/x=B/sub k/x(t/sub k/)+C/sub k/u/sub k/, t=t/sub k/; where the control sequences u/sub k/ belong to some set of admissible controllers that is restricted either by norm or by range. The authors then give a necessary and sufficient condition for global null controllability of time-varying systems and some sufficient conditions for global null controllability for time-invariant systems with special structures. >
Batch-iFDD for representation expansion in large MDPs

Matching pursuit (MP) methods are a promising class of feature construction algorithms for value function approximation. Yet existing MP methods require creating a pool of potential features, mandating expert knowledge or enumeration of a large feature pool, both of which hinder scalability. This paper introduces batch incremental feature dependency discovery (Batch-iFDD) as an MP method that inherits a provable convergence property. Additionally, Batch-iFDD does not require a large pool of features, leading to lower computational complexity. Empirical policy evaluation results across three domains with up to one million states highlight the scalability of Batch-iFDD over the previous state of the art MP algorithm.
Heterocycle‐Substituted Carbohydrate Oxazolines

Glucooxazolines with appended heterocyclic rings have been prepared in a two‐step process involving iodoamidation of protected D‐glucals and subsequent basic cyclization.
Matching pursuit of images

A crucial problem in image analysis is to construct efficient low-level representations of an image, providing precise characterization of features which compose it, such as edges and texture components. An image usually contains very different types of features, which have been successfully modelled by the very redundant family of 2D Gabor oriented wavelets, describing the local properties of the image: localization, scale, preferred orientation, amplitude and phase of the discontinuity. However, this model generates representations of very large size. Instead of decomposing a given image over this whole set of Gabor functions, we use an adaptive algorithm (called matching pursuit) to select the Gabor elements which approximate at best the image, corresponding to the main features of the image. This produces compact representation in terms of few features that reveal the local image properties. Results proved that the elements are precisely localized on the edges of the images, and give a local decomposition as linear combinations of "textons" in the textured regions. We introduce a fast algorithm to compute the matching pursuit decomposition.
The Madden–Julian oscillation wind-convection coupling and the role of moisture processes in the MM5 model

The Madden–Julian oscillation (MJO) produced by a mesoscale model is investigated using standardized statistical diagnostics. Results show that upper- and lower-level zonal winds display the correct MJO structure, phase speed (8 m s−1) and space–time power spectrum. However, the simulated free atmosphere moisture, outgoing longwave radiation and precipitation do not exhibit any clear MJO signal. Yet, the boundary layer moisture, moist static energy and atmospheric instability, measured using a moist static energy instability index, have clear MJO signals. A significant finding is the ability of the model to simulate a realistic MJO phase speed in the winds without reproducing the MJO wind-convection coupling or a realistic propagation in the free atmosphere water vapor. This study suggests that the convergence of boundary layer moisture and the discharge and recharge of the moist static energy and atmospheric instability may be responsible for controlling the speed of propagation of the MJO circulation.