cssi/SciSciGPT-SciSciNet huggingface dataset:
Atmospheric oxidation of reduced sulfur species

The kinetics of elementary gas phase reactions involved in the oxidation of reduced sulfur species, H2S, CS2, OCS, CH3SH, CH3SCH3, and CH3SSCH3, to SO2 (or other products) are reviewed. The reactions with OH and NO3 which are the processes that initiate the degradation of the above compounds have been evaluated. Reactions of key intermediates, HS, HSO, CH3S, and CH3SO, are discussed. Whenever possible, recommendations for the rate coefficients are made and the need for further work indicated. The review has been carried out with the atmospheric chemistry in mind by looking at the laboratory based kinetics data. This review also provides information that will help model the Earth's sulfur cycle.
Star Formation Properties of a Large Sample of Irregular Galaxies

We present the results of Hα imaging of a large sample of irregular galaxies. Our sample includes 94 galaxies with morphological classifications of Im, 26 blue compact dwarfs (BCDs), and 20 Sm systems. The sample spans a large range in galactic parameters, including integrated absolute magnitude (MV of -9 to -19), average surface brightness (20–27 mag arcsec-2), current star formation activity (0–1.3 M⊙ yr-1 kpc-2), and relative gas content (0.02–5 M⊙/LB). The Hα images were used to measure the integrated star formation rates, determine the extents of star formation in the disks, and compare azimuthally averaged radial profiles of current star formation to older starlight. The integrated star formation rates of Im galaxies normalized to the physical size of the galaxy span a range of a factor of 104 with 10% Im galaxies and one Sm system having no measurable star formation at the present time. The BCDs fall, on average, at the high star formation rate end of the range. We find no correlation between star formation activity and proximity to other cataloged galaxies. Two galaxies located in voids are similar in properties to the Sm group in our sample. The H II regions in these galaxies are most often found within the Holmberg radius RH, although in a few systems H II regions are traced as far as 1.7RH. Similarly, most of the star formation is found within three disk scale lengths RD, but in some galaxies H II regions are traced as far as 6RD. A comparison of Hα surface photometry with V-band surface photometry shows that the two approximately follow each other with radius in Sm galaxies, but in most BCDs there is an excess of Hα emission in the centers that drops with radius. In approximately half of the Im galaxies Hα and V correspond well, and in the rest there are small to large differences in the relative rate of falloff with radius. The cases with strong gradients in the LHα/LV ratios and with high central star formation rate densities, which include most of the BCDs, require a significant fraction of their gas to migrate to the center in the last gigayear. We discuss possible torques that could have caused this without leaving an obvious signature, including dark matter bars and past interactions or mergers with small galaxies or H I clouds. There is now a substantial amount of evidence for these processes among many surveys of BCDs. We note that such gas migration will also increase the local pressure and possibly enhance the formation of massive dense clusters but conclude that the star formation process itself does not appear to differ much among BCD, Im, and Sm types. In particular, there is evidence in the distribution function for Hα surface brightness that the turbulent Mach numbers are all about the same in these systems. This follows from the Hα distribution functions corrected for exponential disk gradients, which are log-normal with a nearly constant dispersion. Thus, the influence of shock-triggered star formation is apparently no greater in BCDs than in Im and Sm types.
Should gambling markets be privatized? An examination of state lotteries in the United States

State lotteries currently operate in 43 states across the US. Recently, three states have privatized their lottery operations, handing over the management of their lotteries to private companies in hopes of generating greater revenues for the state governments. Questions arise regarding the economic rationale for this decision and an economic model is presented to determine whether one state, Illinois, has been successful at generating more state transfer revenues as a result of privatization in its first year of results. The issue of lottery privatization is also examined in the larger context of overall growth in the gambling industry in the United States with particular attention paid to sports gambling.
Large-amplitude finite element flutter analysis of composite panels in hypersonic flow

Consideration is given to a finite-element approach for determining the nonlinear flutter characteristics of 3D thin laminated composite panels using the full third-order-piston transverse-loading aerodynamic theory. The unsteady hypersonic aerodynamic theory and the von Karman large-deflection-plate theory are used to formulate the aeroelasticity problem. Nonlinear flutter analyses are performed to assess the influence of the higher-order aerodynamic theory on the structure's limit-cycle amplitude and the dynamic pressure of the flow velocity. A solution procedure is presented to solve the nonlinear panel flutter and large-amplitude free-vibration finite-element equations. Nonlinear flutter analyses are performed for different boundary support-conditions and for various system parameters. Linear finite-element flutter for isotropic and composite panels and large-amplitude isotropic panel flutter results are compared with existing classical solutions. The large-amplitude panel flutter results using the full third-order piston aerodynamic theory are presented to assess the influence of the nonlinear aerodynamic theory.
Impact of Pavement Roughness on Vehicle Free-Flow Speed

In earlier studies of the environmental impact of pavement roughness on life cycle greenhouse gas (GHG) emissions, it was assumed that pavement roughness (usually measured by International Roughness Index, IRI) has no impact on vehicle speed. However, because ride comfort increases when a pavement becomes smoother (that is, when roughness decreases), it is possible that people will drive faster on a smoother pavement. Because most vehicles achieve maximum fuel efficiency between 40 and 50 mph (64 and 80 km/h), fuel use increases at speeds beyond this range, and this increase in speed might offset the benefits gained from the reduced rolling resistance associated with reduced pavement roughness. Therefore, to investigate the impact of changes in pavement roughness on driving behavior with respect to speed, this study built a linear regression model to estimate free-flow speed on freeways in California. The explanatory variables included lane number, total number of lanes, day of the week, region (Caltrans district), gasoline price, and pavement roughness as measured by IRI. Data from the California freeway network from 2000 to 2011 were used to build the model. The results show that pavement roughness has a very small impact on free-flow speed within the range of this study. For the IRI coverage in this study (90 percent of the records have an IRI of 3 m/km or lower and 90 percent of the records have an IRI change of 2 m/km or lower), a change in IRI of 1 m/km (63 in./mi) resulted in a change of average free-flow speed of about 0.48 to 0.64 km/h (0.3 to 0.4 mph), a value low enough to cause almost no change in fuel use. This result indicates that making a rough pavement segment smoother through application of a maintenance or rehabilitation treatment will not result in substantially faster vehicle operating speeds, and therefore the benefits from reduced energy use and emissions due to reduced rolling resistance will not be offset by the increased fuel consumption that accompany increases in vehicle speed. However, efforts to develop a good model for predicting free-flow speed were not fully successful. The Southern California Interstate Freeway model developed yielded the best result with an adjusted Rsquared of 0.72. For the rest of the regions in the state, the selected explanatory variables can only explain about half of the total variance, meaning that there are still other variables, such as vehicle type, with a substantial impact on free-flow speed that were not covered in this study.
Node-covering, error-correcting codes and multiprocessors with very high average fault tolerance

Structural fault tolerance (SFT) is the ability of a multiprocessor to reconfigure around faulty processors or links in order to preserve its original processor interconnection structure; In this paper, we focus on the design of SFT multiprocessors that have low switch and link overheads, but can tolerate a very large number of processor faults on the average. Most previous work has concentrated on deterministic k-fault-tolerant (k-FT) designs in which exactly k spare processors and some spare switches and links are added to construct multiprocessors that can tolerate any k processor faults. However, after k faults are reconfigured around, much of the extra links and switches can remain unutilized. It is possible within the basic node-covering framework, which was introduced by Dutt and Hayes as an efficient k-FT design method, to design FT multiprocessors that have the same amount of switches and links as, say, a two-FT deterministic design, but have s spare processors, where s/spl Gt/2, so that, on the average, k=/spl Theta/(s) (k/spl les/s) processor failures can be reconfigured around. Such designs utilize the spare link and switch capacity very efficiently, and are called probabilistic FT designs. An elegant and powerful method to construct covering graphs or CG's, which are key to obtaining the probabilistic FT designs, is to use linear error-correcting codes (ECCs). We show how to construct probabilistic designs with very high average fault tolerance but low wiring and switch overhead using ECCs like the 2D-parity, full-two, 3D-parity, and full-three codes.
Learning Latent Tree Graphical Models

We study the problem of learning a latent tree graphical model where samples are available only from a subset of variables. We propose two consistent and computationally efficient algorithms for learning minimal latent trees, that is, trees without any redundant hidden nodes. Unlike many existing methods, the observed nodes (or variables) are not constrained to be leaf nodes. Our algorithms can be applied to both discrete and Gaussian random variables and our learned models are such that all the observed and latent variables have the same domain (state space). Our first algorithm, recursive grouping, builds the latent tree recursively by identifying sibling groups using so-called information distances. One of the main contributions of this work is our second algorithm, which we refer to as CLGrouping. CLGrouping starts with a pre-processing procedure in which a tree over the observed variables is constructed. This global step groups the observed nodes that are likely to be close to each other in the true latent tree, thereby guiding subsequent recursive grouping (or equivalent procedures such as neighbor-joining) on much smaller subsets of variables. This results in more accurate and efficient learning of latent trees. We also present regularized versions of our algorithms that learn latent tree approximations of arbitrary distributions. We compare the proposed algorithms to other methods by performing extensive numerical experiments on various latent tree graphical models such as hidden Markov models and star graphs. In addition, we demonstrate the applicability of our methods on real-world data sets by modeling the dependency structure of monthly stock returns in the S&P index and of the words in the 20 newsgroups data set.
From Home to Hospital: The Evolution of Childbirth in the United States, 1927-1940

Abstract This paper examines the shift in childbirth from home to hospital that occurred in the United States in the early 20th century. Using a panel of city-level data over the period 1928–1940, we examine the impact on maternal mortality resulting from the shift of childbirth from home to hospital. Results suggest that until the late 1930s when sulfa drugs were developed, medical intervention had a limited impact on maternal mortality. Post-sulfa, the medicalization of childbirth reduced maternal mortality. Regressions estimated separately by race provide mixed evidence as to whether blacks and whites benefited differentially from medical intervention.
Postobstructive regeneration of kidney is derailed when surge in renal stem cells during course of unilateral ureteral obstruction is halted

Unilateral ureteral obstruction (UUO), a model of tubulointerstitial scarring (TIS), has a propensity toward regeneration of renal parenchyma after release of obstruction (RUUO). No information exists on the contribution of stem cells to this process. We performed UUO in FVB/N mice, reversed it after 10 days, and examined kidneys 3 wk after RUUO. UUO resulted in attenuation of renal parenchyma. FACS analysis of endothelial progenitor (EPC), mesenchymal stem (MSC) and hematopoietic stem (HSC) cells obtained from UUO kidneys by collagenase-dispersed single-cell suspension showed significant increase in EPC, MSC, and HSC compared with control. After RUUO cortical parenchyma was nearly restored, and TIS score improved by 3 wk. This reversal process was associated with return of stem cells toward baseline level. When animals were chronically treated with nitric oxide synthase (NOS) inhibitor at a dose that did not induce hypertension but resulted in endothelial dysfunction, TIS scores were not different from control UUO, but EPC number in the kidney decreased significantly; however, parenchymal regeneration in these mice was similar to control. Blockade of CXCR4-mediated engraftment resulted in dramatic worsening of UUO and RUUO. Similar results were obtained in caveolin-1-deficient but not -overexpressing mice, reflecting the fact that activation of CXCR4 occurs in caveolae. The present data show increase in EPC, HSC, and MSC population during UUO and a tendency for these cells to decrease to control level during RUUO. These processes are minimally affected by chronic NOS inhibition. Blockade of CXCR4-stromal cell-derived factor-1 (SDF-1) interaction by AMD3100 or caveolin-1 deficiency significantly reduced the UUO-associated surge in stem cells and prevented parenchymal regeneration after RUUO. We conclude that the surge in stem cell accumulation during UUO is a prerequisite for regeneration of renal parenchyma.
Simulation of InAsSb/InGaAs Quantum Dots for Optical Device Applications

Self-assembled InAsSb/InGaAs quantum dots are candidates for optical detectors and emitters in the 2-5 micron band with a wide range of applications for atmospheric chemistry studies. It is known that while the energy band gap of unstrained bulk InAsp1-xSbx is smallest for x=0.62, the biaxial strain for bulk InAsp1-xSbx grown on In0.53Ga0.47As shifts the energy gap to higher energies and the smallest band gap is reached for x=0.51. The aim of the present study is to examine how the electronic confinement in the quantum dots modifies these simple considerations. We have calculated the electronic structure of lens shaped InAs1-xSbx quantum dots with diameter 37 nm and height 4 nm embedded in a In0.53Ga0.47As matrix of thickness 7 nm and lattice matched to an InP buffer. The relaxed atomic positions were determined by minimizing the elastic energy obtained from a valence force field description of the inter-atomic interaction. The electronic structure was calculated with an empirical tight binding approach. For Sb concentrations larger than x=0.5, it is found that the InSb/ In0.53Ga0.47As heterostructure becomes type II leading to no electron confined in the dot. It is also found that the energy gap decreases with increasing Sb content in contradiction with previous experimental results. A possible explanation is a significant variation is quantum dot size with Sb content.
Decoherence in nanostructures and quantum systems

Abstract Decoherence phenomena are pervasive in the arena of nanostructures but perhaps even more so in the study of the fundamentals of quantum mechanics and quantum computation. Since there has been little overlap between the studies in both arenas, this is an attempt to bridge the gap. Topics stressed include (a) wave packet spreading in a dissipative environment, a key element in all arenas, (b) the definition of a quantitative measure of decoherence, (c) the near zero and zero temperature limit, and (d) the key role played by initial conditions: system and environment entangled at all times so that one must use the density matrix (or Wigner distribution) for the complete system or initially decoupled system and environment so that use of a reduced density matrix or reduced Wigner distribution is feasible. Our approach utilizes generalized quantum Langevin equations and Wigner distributions.
Integral Points of Small Height Outside of a Hypersurface

Let F be a non-zero polynomial with integer coefficients in N variables of degree M. We prove the existence of an integral point of small height at which F does not vanish. Our basic bound depends on N and M only. We separately investigate the case when F is decomposable into a product of linear forms, and provide a more sophisticated bound. We also relate this problem to a certain extension of Siegel’s Lemma as well as to Faltings’ version of it. Finally we exhibit an application of our results to a discrete version of the Tarski plank problem.
Roentgenographic and Direct Observation of Experimental Lesions in Bone: I†

To simulate periodontal and periapical lesions, bone cuts were made in mandibles from human cadavers, and the roentgenographic and visual appearances of the bone were compared. It is evident that inflammatory or tumorous lesions cannot be visualized if they are confined within the cancellous bone. However, if the lesions erode the junction area of the cortex and cancellous bone or perforate the cortex, they can be distinguished roentgenographically. Early stages of bone disease cannot be detected by means of routine roentgenograms, nor can the size of a rarefied area on the roentgenogram be correlated with the amount of tissue destruction.
Optimal corner detector

A corner is defined as the junction point of two or more stright line edges. Corners are special features in a image. They are of great use in computing the optical flow and structure from motion. In this paper, we report an optimal corner detector which uses a mathematical model for a corner. An optimal gray tone corner detector is derived for a restricted case of corners, i.e., corners made by lines which are symmetric about a horizontal axis. The resultant corner detector is described by the product of the sine in x and an exponential in the y direction in a portion of the mask and by the product of two sines in x and y directions in the remaining portion. It is then generalized to include any corner of an arbitrary angle and orientation. This results in an approximation of all corners by a total of twelve major types. It is observed that all the twelve masks can actually be configured with four smaller sub-masks, and this results in a significant reduction in the computations. The computations are further reduced by using the separability of masks. Results for synthetic and real scenes are reported.
Quantitative Limiting Absorption Principle in the Semiclassical Limit

We give an elementary proof of Burq’s resolvent bounds for long range semiclassical Schrodinger operators. Globally, the resolvent norm grows exponentially in the inverse semiclassical parameter, and near infinity it grows linearly. We also weaken the regularity assumptions on the potential.
The evolution of wide binary stars

We study the orbital evolution of wide binary stars in the solar neighbourhood due to gravitational perturbations from passing stars. We include the effects of the Galactic tidal field and continue to follow the stars after they become unbound. For a wide variety of initial semimajor axes and formation times, we find that the number density (stars per unit logarithmic interval in projected separation) exhibits a minimum at a few times the Jacobi radius r J , which equals 1.7 pc for a binary of solar-mass stars. The density peak interior to this minimum arises from the primordial distribution of bound binaries, and the exterior density, which peaks at a separation of ∼100-300 pc, arises from formerly bound binaries that are slowly drifting apart. The exterior peak gives rise to a significant long-range correlation in the positions and velocities of disc stars that should be detectable in large astrometric surveys such as Gaia that can measure accurate three-dimensional distances and velocities.
Polyphase FIR filters for the demodulation of chrominance signals

The author presents an estimation scheme and its polyphase finite-duration impulse-response (FIR) filter implementation for the demodulation of composite chrominance signals into color difference components such as in-phase and quadrature-phase components. A decoding scheme with three-tap polyphase FIR filters is presented. The least square error estimators, which estimate the chrominance components, are derived and their performance analyzed. The composite video signal is reviewed and the digitization of the video signal is described. The author formulates the demodulation of the digitized video signal as an estimation problem. A polyphase FIR filter implementation of the resultant estimators for the chrominance components is then described. >
Beam-beam effects with errors in the crab compensation

The effect of the beam-beam interaction in the presence of errors in the crab compensation for a crossing angle is shown to be asymmetric with respect to both beams. A comparison with experience at CESR with colliding beams with dispersion indicates that the tolerances for the crab compensation are not stringent. >
Stein's method, heat kernel, and traces of powers of elements of compact Lie groups

Combining Stein's method with heat kernel techniques, we show that the trace of the jth power of an element of U(n,C), USp(n,C), or SO(n,R) has a normal limit with error term C j/n, with C an absolute constant. In contrast to previous works, here j may be growing with n. The technique might prove useful in the study of the value distribution of approximate eigenfunctions of Laplacians.
A 12 Day ASCA Observation of the Narrow-Line Seyfert 1 Galaxy Ton S180: Time-selected Spectroscopy

We present an analysis of the X-ray variability properties of the narrow-line Seyfert 1 galaxy Ton S180, based on a 12 day continuous observation with ASCA. Examination of the light curves reveals flux variations of a factor of 3.5 in the 0.7-1.3 keV band and 3.9 in the 2-10 keV band. Time-resolved spectroscopy, using approximately daily sampling, reveals that the broad "soft hump" component at energies less than 2 keV shows flux variations on timescales as short as 1 day that are well correlated with the photon index and the 2-10 keV band flux. A broad Fe Kα emission is detected. There is also statistically significant evidence for a narrow Fe Kα line at ~6.8 keV, indicating an origin in ionized material. We do not detect significant variations of the Fe Kα line flux or equivalent width on timescales of ~1 day to 1 week. Despite evidence for correlated events in the power law and soft hump on timescales of a day, the flux correlations clearly do not exist on all timescales. In particular, the softness ratio reveals spectral variability on timescales as short as ~1000 s, indicating that the power-law continuum and soft hump fluxes are not well correlated on this timescale. The softness ratio also shows a slow decline across the observation, due to a combination of the different time variability of the power-law continuum and soft hump flux on timescales of ~1 week. Our timing analysis and time-selected spectroscopy indicate that the X-ray emission originates within 12 Schwarzschild radii. The amplitudes and timescales of the rapid variations that we observed are consistent with those expected within disk-corona models. Furthermore, the observed fast variability of the soft hump rules out an origin of the soft emission in large-scale components, such as circumnuclear starburst. The Γ-soft hump correlation is consistent with the soft hump being produced by upscattering of the accretion disk radiation within a patchy, flaring disk corona.
Teachers' Perspectives on Educational Research.

Based on two studies conducted in the Chicago metropolitan area in 2009 and 2010, we found that teachers do, in fact, use research, although they tend to seek it out under very specific conditions and circumstances. Namely, teachers tend to look to research in response to an immediate, pressing concern such as how to best teach fractions to English language learners (ELLs). Teachers also turn to research to address a specific content need, such as gathering information for an upcoming lesson. In terms of broader reviews of research, teachers sometimes review research they have used in the past, such as best practices for a particular topic or method. Finally, teachers may consult educational research when they participate in groups that use research findings to more broadly support their instructional practice (e.g., study groups, committees or courses on using research in the classroom).
A pragmatic approach to integrated process/device/circuit simulation for IC technology development

A novel approach to integrated process/device/circuit simulation is proposed which allows pragmatic, computationally efficient IC technology CAD at the mixed-mode device/circuit level. The approach is demonstrated with a simulation system for advanced silicon bipolar technologies. This system comprises the process simulator SUPREM-3 integrated with the seminumerical mixed-mode device/circuit simulator MMSPICE by a program called SUMM. The integration is characterized by the unique evaluation of the physical (structure-dependent) parameters for the MMSPICE BJT model from a one-dimensional doping profile generated by SUPREM-3 without any optimization-based extraction. The capability of the application-specific SUMM/MMSPICE integrated system to reliably predict device characteristics and their sensitivities to process-flow variations is verified by measurements and by purely numerical simulations with PISCES-II. The utility of the system in IC technology development is exemplified by simulations. >
Construction of symplectic full-turn maps by application of an arbitrary tracking code

It is pointed out that a map to describe propagation of particles through any section of a nonlinear lattice can be represented as a Taylor expansion about the origin in phase space. Although the technique to compute the Taylor coefficients has been improved recently, the expansion may fail to provide adequate accuracy in regions where nonlinear effects are substantial. It is suggested that a representation of the map in angle-action coordinates, with the angle dependence given by a Fourier series and the action dependence by polynomials in I/sup 1/2/, may be more successful. Maps of this form are easily constructed by taking Fourier transforms of results from an arbitrary symplectic tracking code. Examples are given of one-turn and two-turn maps for the SLC (Stanford Linear Collider) North Damping Ring in a strongly nonlinear region. Results for accuracy and speed of evaluation of the maps are quite encouraging. It seems feasible to make accurate maps for the SSC (Superconducting Super Collider) by this method. >
Synthetic and Immunological Studies on Clustered Modes of Mucin-Related Tn and TF O-Linked Antigens: The Preparation of a Glycopeptide-Based Vaccine for Clinical Trials against Prostate Cancer†

The syntheses of two tumor-associated carbohydrate antigens, Tn and TF, have been achieved using glycal assembly and cassette methodologies. These synthetic antigens were subsequently clustered (c) and immunoconjugated to a carrier protein (KLH or BSA) or a synthetic lipopeptide (pam) for immunological study. Three Tn conjugates were used to vaccinate groups of mice, and all preparations proved to be immunogenic. The Tn(c) covalently linked to KLH (27−KLH) plus the adjuvant QS-21 was the optimal vaccine, inducing high median IgM and IgG titers against Tn(c) by ELISA. These antibodies were strongly reactive with the Tn(c) positive human colon cancer cell line LS-C but not the Tn(c) negative colon cancer cell line LS-B by FACS. The antibodies' reactivities with natural antigens were inhibited with synthetic Tn(c) but not with structurally unrelated compounds. On the basis of these results, vaccines containing 27−KLH and 30−pam plus QS-21 are being tested in patients with prostate cancer.
Diversity Analysis of Symbol-by-Symbol Linear Equalizers

In frequency-selective channels linear receivers enjoy significantly-reduced complexity compared with maximum likelihood receivers at the cost of performance degradation which can be in the form of a loss of the inherent frequency diversity order or reduced coding gain. This paper demonstrates that the minimum mean-square error symbol-by-symbol linear equalizer incurs no diversity loss compared to the maximum likelihood receivers. In particular, for a channel with memory ν, it achieves the full diversity order of (ν+1) while the zero-forcing symbol-by-symbol linear equalizer always achieves a diversity order of one.
PROGRAMS TO COMBAT NUTRITIONAL QUACKERY

What avenues are available to combat the nutritional misinformation and quackery with which the public is bombarded?
Favor trading in public good provision

Favor trading is common. We do something nice for someone and they do something nice in return. Several motives might underlie such behavior, including altruism, strategic motives, and direct or indirect positive reciprocity. It is not yet well-understood how these fit together to affect behavior, how they interact in various institutional structures, and how they play out over time. We use a laboratory experiment to study the elements and dynamics of favor trading in a particular setting: the private provision of a public good. In our experiment, giving subjects the ability to practice targeted reciprocity by making a simple, low-cost change in information provision increases contributions to the public good by 14 %. Subjects reward group members who have previously been generous to them and withhold rewards from ungenerous group members. Strategic concerns cannot explain all of this behavior, and it must be at least partly due to direct reciprocity. When someone cannot directly benefit from favor trading, he gives much less to the public good. People thus excluded from the “circle of reciprocity” provide a clean and strict test of indirect reciprocity. Contrary to previous studies in the literature, we do not observe indirect reciprocity.
Detection of the red giant branch stars in m82 using the hubble space telescope

We present color-magnitude diagrams and luminosity functions or stars in two halo regions of the irregular galaxy in M82, based on F555W and F814W photometry taken with the Hubble Space Telescope and Wide Field Planetary Camera 2.
The effects of simulated cataract on reading with normal vision and simulated central scotoma.

Abstract Reading rates are slower for persons with low vision than for normally-sighted persons. This study investigated the change in reading performance and reading eye movements when we simulated the two most common causes of low vision — central field loss and cataract — and their combination (scotoma+cataract). Three subjects read sentences with each of these simulated impairments at five different letter sizes. They required larger letters to read with the cataract or scotoma than they did with normal vision, and larger still to read with scotoma+cataract; the change in eye movements relative to normal vision was similar across conditions. When reading large letters (1.61°), the cataract had almost no effect, while the scotoma and scotoma+cataract reduced reading rate for two of the subjects. The cataract had a greater impact on performance relative to normal vision for these same two subjects, while for the third subject the cataract had a greater impact with the scotoma in place. Cataract extraction tends to be postponed in patients with central field loss because it is not perceived to be beneficial. The findings from this study, as well as others, suggest that patients with central field loss would benefit from cataract extraction.
Prediction of fullerene packing in C60 and C70 crystals

Recent breakthroughs in synthesizing large amounts of C_(60), C_(70) and other fullerenes have made possible studies of the struc-tures and properties of fullerene crystals. Using a force field developed recently for sp carbon atoms, we predict here the crystal structures and cohesive energies for close-packed crystals of C_(60) and C_(70). We predict, and confirm from calculations, that for C_(60) face-centred cubic (f.c.c.) packing is more stable than hexagonal close-packing (h.c.p.), by 0.90 kcal mol−1, whereas for C70 h.c.p. is more stable than f.c.c. by 0.35 kcal mol^(−1). The cubic structure of C60 undergoes an orthorhombic distortion to space group Cmca at 0 K. At higher temperatures there is rapid reorientation (but not free rotation) of C_(60) molecules, suggesting that above about 200 K a phase transition occurs to an orientationally disordered, f.c.c. structure (with a room-temperature lattice parameter of 14.13 A). This may correspond to the first-order transition observed at 249 K. The threefold axes of the C_(60) molecules in the low-temperature structure are not aligned with the threefold crystallographic axes.
Computing the first few Betti numbers of semi-algebraic sets in single exponential time

Abstract In this paper we describe an algorithm that takes as input a description of a semi-algebraic set S ⊂ R k , defined by a Boolean formula with atoms of the form P > 0 , P 0 , P = 0 for P ∈ P ⊂ R [ X 1 , … , X k ] , and outputs the first l + 1 Betti numbers of S , b 0 ( S ) , … , b l ( S ) . The complexity of the algorithm is ( s d ) k O ( l ) , where s = # ( P ) and d = max P ∈ P deg ( P ) , which is singly exponential in k for l any fixed constant. Previously, singly exponential time algorithms were known only for computing the Euler–Poincare characteristic, the zeroth and the first Betti numbers.
Expected Firm Altruism, Quality Provision, and Brand Extensions

A setting is considered where consumers keep track of the extent to which brands care about them, which is modeled as altruism of brands toward their target consumers. Consumers who purchase an experience good of high quality reasonably deduce that the supplier of this good is relatively altruistic toward them, and they are therefore more keen to purchase a brand extension that is also directed at them. As a result, the success of brand extensions depends on the overlap between the customers of the original product and the target customers of the extension product. The quality and demand for a brand extension can be higher if the brand is perceived as caring only for its most quality-conscious consumers rather than for all possible buyers of the good.
Estimation of the Value of Old World Bluestem and Optimum Grazing Season under Alternative Stocking Rates

The production potential of OWB forage is evaluated under commercial rotational grazing management. The economic value of the forage is determined by the replacement value of the CP and TDN content. The optimal grazing period is determined where the MVP of grazing an additional day is equal to the MFC.
User-Generated Content and Bias in News Media

In this study, we investigate newspapers' decision to expand their product lines by adding online editions that incorporate user-generated content. We demonstrate that such product line extensions mitigate the extent of slanting in print media. The results also show that as the extent of discretion of users to generate online content increases, print versions of newspapers become more polarized. Furthermore, adding online editions results in reduced profits for newspapers as the additional product variants increase the intensity of competition in the market and the discretion awarded to users limits the ability of newspapers to extract rents from consumers. Data, as supplemental material, are available at http://dx.doi.org/10.1287/mnsc.2013.1746 . This paper was accepted by J. Miguel Villas-Boas, marketing.
Parsing Algorithms and Metrics

Many different metrics exist for evaluating parsing results, including Viterbi, Crossing Brackets Rate, Zero Crossing Brackets Rate, and several others. However, most parsing algorithms, including the Viterbi algorithm, attempt to optimize the same metric, namely the probability of getting the correct labelled tree. By choosing a parsing algorithm appropriate for the evaluation metric, better performance can be achieved. We present two new algorithms: the "Labelled Recall Algorithm," which maximizes the expected Labelled Recall Rate, and the "Bracketed Recall Algorithm," which maximizes the Bracketed Recall Rate. Experimental results are given, showing that the two new algorithms have improved performance over the Viterbi algorithm on many criteria, especially the ones that they optimize.
Copper/titanium catalysis forms fully substituted carbon centers from the direct coupling of acyclic ketones, amines, and alkynes.

Three-component coupling, with a pair: The combination of Cu(II) and Ti(IV) catalyzes the first three-component coupling of unactivated ketones with a diverse range of amines and terminal alkynes. Tetrasubstituted propargylamines are formed under green, solvent-free conditions. This dual metal system overcomes the barrier to ketimine formation and subsequent attack, opening a new path to multicomponent reactions of ketone electrophiles.
Sets of Integers that do not Contain Long Arithmetic Progressions

Combining ideas of Rankin, Elkin, Green & Wolf, we give constructive lower bounds for $r_k(N)$, the largest size of a subset of $\{1,2,\dots,N\}$ that does not contain a $k$-element arithmetic progression: For every $\epsilon>0$, if $N$ is sufficiently large, then $$r_3(N) \geq N \left(\frac{6\cdot 2^{3/4} \sqrt{5}}{e \,\pi^{3/2}}-\epsilon\right) \exp\left({-\sqrt{8\log N}+\tfrac14\log\log N}\right),$$ $$r_k(N) \geq N \, C_k\,\exp\left({-n 2^{(n-1)/2} \sqrt[n]{\log N}+\tfrac{1}{2n}\log\log N}\right),$$ where $C_k>0$ is an unspecified constant, $\log=\log_2$, $\exp(x)=2^x$, and $n=\lceil{\log k}\rceil$. These are currently the best lower bounds for all $k$, and are an improvement over previous lower bounds for all $k\neq4$.
Diffusive Logistic Model Towards Predicting Information Diffusion in Online Social Networks

Online social networks have recently become an effective and innovative channel for spreading information and influence among hundreds of millions of end users. Most of prior work either carried out empirical studies or focus on the information diffusion modeling in temporal dimension, little attempt has been given on understanding information diffusion over both temporal and spatial dimensions. In this paper, we propose a Partial Differential Equation (PDE), specifically, a Diffusive Logistic (DL) equation to model the temporal and spatial characteristics of information diffusion. We present the temporal and spatial patterns in a real dataset collected from a social news aggregation site, Digg, and validate the proposed DL equation in terms of predicting the information diffusion process. Our experiment results show that the DL model is able to characterize and predict the process of information propagation in online social networks. For example, for the most popular news with 24,099 votes in Digg, the average prediction accuracy of DL model over all distances during the first 6 hours is 92.08%. To the best of our knowledge, this paper is the first attempt to use PDE-based model to study the information diffusion process in both temporal and spatial dimensions in online social networks.
Counting characters in linear group actions

Let G be a finite group and V be a finite G-module. We present upper bounds for the cardinalities of certain subsets of Irr(GV), such as the set of those χ ∈ Irr(GV) such that, for a fixed v ∈ V, the restriction of χ to 〈v〉 is not a multiple of the regular character of 〈v〉. These results might be useful in attacking the noncoprime k(GV)-problem.
Co-Evolution of Firms and Consumers and the Implications for Market Dominance

Consider a setting in which $rms randomly discover new ideas that a-ect their products or services and implement favorable ones. At the same time that $rms are adapting their o-erings, consumers are searching among $rms for the best match. It is shown that implicit in these dual dynamics is an increasing returns mechanism which can result in one $rm dominating the market in the long run. The conditions under which there is sustained market dominance are characterized.
Scalability of genetic programming and probabilistic incremental program evolution

Radovan Ondas University of Missouri St. Louis Dept. of Math and Computer Science, CCB 331 8001 Natural Bridge Rd. St. Louis, MO 63121, USA ondasr@umsl.edu Martin Pelikan University of Missouri St. Louis Dept. of Math and Computer Science CCB 320 8001 Natural Bridge Rd. St. Louis, MO 63121, USA pelikan@cs.umsl.edu Kumara Sastry University of Illinois at Urbana-Champaign Dept. of General Engineering 117 Transportation Bldg. 104 S. Mathews Ave. Urbana, IL 61801, USA ksastry@uiuc.edu
Arcs in the plane

Abstract Assuming PFA, every uncountable subset E of the plane meets some C 1 arc in an uncountable set. This is not provable from MA ( ℵ 1 ) , although in the case that E is analytic, this is a ZFC result. The result is false in ZFC for C 2 arcs, and the counter-example is a perfect set.
Object detection in multi-epoch data

In astronomy multiple images are frequently obtained at the same position of the sky for follow-up coaddition as it helps one go deeper and look for fainter objects. With large scale panchromatic synoptic surveys becoming more common, image co-addition has become even more necessary as new observations start to get compared with coadded fiducial sky in real time. The standard coaddition techniques have included straight averages, variance weighted averages, medians etc. A more sophisticated nonlinear response chi-square method is also used when it is known that the data are background noise limited and the point spread function is homogenized in all channels. A more robust object detection technique capable of detecting faint sources, even those not seen at all epochs which will normally be smoothed out in traditional methods, is described. The analysis at each pixel level is based on a formula similar to Mahalanobis distance. c 2008 Elsevier B.V. All rights reserved.
A Register Allocation Algorithm in the Presence of Scalar Replacement for Fine-Grain Configurable Architectures

The aggressive application of scalar replacement to array references substantially reduces the number of memory operations at the expense of a possibly very large number of registers. In this paper we describe a register allocation algorithm that assigns registers to scalar replaced array references along the critical paths of a computation, in many cases exploiting the opportunity for concurrent memory accesses. Experimental results, for a set of image/signal processing code kernels, reveal that the proposed algorithm leads to a substantial reduction of the number of execution cycles for the corresponding hardware implementation on a contemporary Field-Programmable-Gate-Array (FPGA) when compared to other greedy allocation algorithms, in some cases, using even fewer number of registers.
Farmer Trust in Agricultural Cooperatives: Evidence from Missouri Corn and Soybean Producers

We examine whether cooperatives are characterized by greater trust than investor- owned firms. We survey 2000 Missouri corn and soybean farmers and find that trust and farmer perceptions of trustworthiness and competence are higher in cooperatives than in investor-owned firms and that trust is a significant factor explaining the choice of farmers to market to cooperatives rather than investor-owned firms. Interestingly, we find that trust is more significant in producers' decisions for marketing soybeans than for corn.
Justifying human rights: economics and the individual

This paper examines the relationship between the individual conception in economics and the justification of economic rights as human rights. It briefly describes the nature of economic rights, and argues that the Homo economicus conception constitutes a barrier to justifying them. The paper then offers an alternative conception of the individual as socially embedded, and argues that it offers an adequate basis for the justification of economic rights. On this alternative conception individuals are enduring beings who have personal identities.
Recursion and corecursion have the same equational logic

This paper is concerned with the equational logic of definitions whose semantics is given in terms of final coalgebra maps. The framework for our study is iteration theories (cf. e.g. Bloom and Esik, Iteration Theories: The Equational Logic of Iterative Processes, EATCS Monographs on Theoretical Computer Science, Springer, Berlin, 1993; Theoret. Comput. Sci. 179 (1-2) (1997)), recently re-introduced as models of the FLR0 fragment of the formal language of recursion (Hurkens et al., J. Symbolic Logic 63 (2) (1998) 45; Mos Chovakis, J. Symbolic Logic 54 (1989) 1216; in: M.L. Dalla Chiara et al. (Eds.), Logic and Scientific Methods, Kluwer, Dordrecht, 1997, p. 179). We present a new class of iteration theories derived from final coalgebras. This allows us to reason with a number of types of fixed-point equations which heretofore seemed to require metric or order-theoretic ideas. All of the work can be done using finality properties and equational reasoning. Having a semantics, we obtain the following completeness result: the equations involving fixed-point terms which are valid for final coalgebra interpretations are exactly those valid in a number of contexts pertaining to recursion. For example, they coincide with the equations valid for least-fixed-point recursion on dcpo's. We also present a new version of the proof of the well-known completeness result for iteration theories (see Esik, Comput. Linguistics Comput. Languages 4 (1982) 95; Hurkens et al., 1998). Our work brings out a connection between coalgebraic reasoning and recursion.
A model for the pioneer anomaly

In a previous work, we showed that massive test particles exhibit a nongeodesic acceleration in a modified theory of gravity obtained by a noncommutative deformation of General Relativity (so-called Matrix Gravity). We propose that this nongeodesic acceleration might be the origin of the anomalous acceleration experienced by the Pioneer 10 and Pioneer 11 spacecrafts.
Exact calculation of computer network reliability

In designing a distributed computer network, the reliability and availability of the communication paths between all pairs of centers is a primary consideration. Many different approaches have been taken to calculate exactly the probability of successful communication between any specified pair of centers, for a given failure probability of the individual computer systems and communication facilities. However, almost all of these methods are not computationally feasible for large networks. Consequently, approximate calculations of network reliability have been suggested. In this paper a procedure is given for the exact calculation of the probability that all paths between a pair of nodes in a given network are interrupted. The procedure generates mutually exclusive sets of cutting states and calculates the probability of the related events. Summing these values one obtains the probability of service interruption between the specified pair of nodes. If all links fail with equal probability p, the coefficients of a polynomial can be calculated, describing the service disruption probability as a function of p.