cssi/SciSciGPT-SciSciNet huggingface dataset:
Integral Field Unit Observations of NGC 891: Kinematics of the Diffuse Ionized Gas Halo

We present high and moderate spectral resolution spectroscopy of diffuse ionized gas (DIG) emission in the halo of NGC 891. The data were obtained with the SparsePak integral field unit at the WIYN Observatory. The wavelength coverage includes the [N II] λλ6548, 6583, Hα, and [S II] λλ6716, 6731 emission lines. Position-velocity (PV) diagrams, constructed using spectra extracted from four SparsePak pointings in the halo, are used to examine the kinematics of the DIG. Using two independent methods, a vertical gradient in azimuthal velocity is found to be present in the northeast quadrant of the halo, with magnitude approximately 15-18 km s-1 kpc-1, in agreement with results from H I observations. The kinematics of the DIG suggests that this gradient begins at approximately 1 kpc above the midplane. In another part of the halo, the southeast quadrant, the kinematics is markedly different and suggest rotation at about 175 km s-1, much slower than the disk but with no vertical gradient. We use an entirely ballistic model of disk-halo flow in an attempt to reproduce the kinematics observed in the northeast quadrant. Analysis shows that the velocity gradient predicted by the ballistic model is far too shallow. Based on intensity cuts made parallel to the major axis in the ballistic model and an Hα image of NGC 891 from the literature, we conclude that the DIG halo is much more centrally concentrated than the model, suggesting that hydrodynamics dominate over ballistic motion in shaping the density structure of the halo. Velocity dispersion measurements along the minor axis of NGC 891 seem to indicate a lack of radial motions in the halo, but the uncertainties do not allow us to set firm limits.
Probing Heliospheric Asymmetries with an MHD-Kinetic model

New solar wind data from the Voyager 1 and Voyager 2 spacecraft, together with the SOHO SWAN measurements of the direction in which neutral hydrogen enters into the inner heliosheath and neutral helium measurements provided by multiple observations, are expected to provide more reliable constraints on the ionization ratio of the local interstellar medium (LISM) and the direction and magnitude of the interstellar magnetic field (ISMF). In this Letter we use the currently most sophisticated numerical model of the heliospheric interface, which is based on an MHD treatment of the ion flow and kinetic modeling of neutral particles, to analyze an ISMF-induced asymmetry of the heliosphere in the presence of the interplanetary magnetic field and neutral particles. It is shown that secondary hydrogen atoms modify the LISM properties leading to its shock-free deceleration at the heliopause. We determine the deflection of hydrogen atoms from their original trajectory in the unperturbed LISM and show that it occurs not only in the plane defined by the ISMF and LISM velocity vectors, but also, to a lesser extent, perpendicular to this plane. We also consider the possibility of using 2-3 kHz radio emission data to further constrain the ISMF direction.
Thermal control of space X-ray experiment

A thermal control system has been designed for the Uniformly Redundant Array (URA), which is a shuttle-launched scientific experiment to detect and map x-ray sources in space. Tasks included the design, development, installation, and testing of the thermal control system for the experiment. The URA thermal control system must assure that the various components of the experiment survive and remain within operational temperature limits when exposed to temperature extremes of space resulting from different shuttle orientations. A thermal model was developed to simulate different orbital configurations and thermal-vacuum tests were conducted to test the reliability of the thermal hardware, and verify the thermal model. The tests and analyses indicated that the thermal control system was able to meet the design goals.
Loss Aversion and Saving Behavior: Evidence from the 2007 U.S. Survey of Consumer Finances

This study uses data from the 2007 Survey of Consumer Finances to examine household saving behavior based on the two-period model of consumption/saving presented by Bowman et al. (Econ Behav Organ 38:155–178, 1999). The main focus of the model is the existence of an asymmetry in saving behavior in response to positive and negative adjustments in income. The results of the logistic regression analysis support the existence of loss aversion at the household level, where having income below the household’s reference level significantly decreases the likelihood of saving, but having income above the household’s reference level does not have a significant effect on the likelihood of saving.
The Spectrum of the Partially Locked State for the Kuramoto Model

We solve a long-standing stability problem for the Kuramoto model of coupled oscillators. This system has attracted mathematical attention, in part because of its applications in fields ranging from neuroscience to condensed-matter physics, and also because it provides a beautiful connection between nonlinear dynamics and statistical mechanics. The model consists of a large population of phase oscillators with all-to-all sinusoidal coupling. The oscillators' intrinsic frequencies are randomly distributed across the population according to a prescribed probability density, here taken to be unimodal and symmetric about its mean. As the coupling between the oscillators is increased, the system spontaneously synchronizes: The oscillators near the center of the frequency distribution lock their phases together and run at the same frequency, while those in the tails remain unlocked and drift at different frequencies. Although this "partially locked" state has been observed in simulations for decades, its stability has never been analyzed mathematically. Part of the difficulty is in formulating a reasonable infinite-N limit of the model. Here we describe such a continuum limit, and prove that the corresponding partially locked state is, in fact, neutrally stable, contrary to what one might have expected. The possible implications of this result are discussed.
Analysis of the binding surfaces of proteins.

We have developed an experimental approach to map the complete binding surface of any crystalline macromolecule that is fast and flexible. Crystals of the target protein are transferred into organic solvents and the crystal structures are determined at high (about 2A) resolution. The sites where the solvent molecules bind to the protein are thus identified directly. Different solvents serve as probes for different organic functional groups; thus, benzene is a probe for where aromatic groups like to bind, dimethyl formamide is a probe for peptide binding sites, and so forth. A series of about six such experiments suffices to locate the major binding regions on the protein surface unambiguously. These different sites can then be targeted with “Hydra-headed” inhibitors that interact simultaneously with more that one site, thereby providing specificity for the desired target. We have used this method to map the complete binding surface of elastase, and find that three regions, including the active site cleft, are generally “sticky” and can make interactions with almost any functional group. Analyses of these binding sites on elastase and other proteins suggests that what makes a binding site is amphipathicity and the ease with which water can be displaced. © 1999 John Wiley & Sons, Inc. Med Res Rev, 19, No. 4, 321–331, 1999.
INTRODUCTION TO ECONOMIC MODELS OF CRIME

This introduction to the IER symposium on economic models of crime briefly reviews the articles in this issue and tries to put them in the context of the current research on the economics of crime.
Mobility and manipulation of a light-weight space robot

Abstract We have developed a light-weight space manipulator, Self-Mobile Manipulator (SM2), in the Robotics Institute of Carnegie Mellon University. SM2 is a 7 DOF, 1 3 - scale , laboratory version of a robot designed to walk on the trusswork and other exterior surfaces of Space Station Freedom, and to perform manipulation tasks that are required for inspection, maintenance, and construction. Combining the mobility and manipulation functions in one body SM2, as a mobile manipulator, is capable of routine tasks such as inspection, parts transportation, object lighting, and simple assembly procedures. The system will provide assistance to astronauts and greatly reduce the need for astronaut extra-vehicular activity (EVA). This paper discusses the robot hardware development, gravity compensation system, control structure and teleoperation functions of SM2 system, and demonstrates its capabilities of locomotion and manipulation in space applications.
Nonlinear wave equations and constrained harmonic motion.

Abstract The study of the Korteweg-deVries, nonlinear Schrodinger, Sine-Gordon, and Toda lattice equations is simply the study of constrained oscillators. This is likely to be true for any nonlinear wave equation associated with a second-order linear problem.
Collisionless Relaxation in Galactic Dynamics and the Evolution of Long‐Range Order

: This paper presents a critical assessment of certain aspects of collisionless galactic dynamics, focusing on the interpretation and limitations of the collisionless Boltzmann equation and the physical mechanisms associated with collisionless, or near-collisionless, relaxation. Numerical and theoretical arguments are presented to motivate the idea that the evolution of a system far from equilibrium should be interpreted as involving nonlinear gravitational landau damping, a picture which implies a greater overall coherence and remembrance of initial conditions than is implicit in the conventional paradigm of violent relaxation.
Sortable elements in infinite Coxeter groups

In a series of previous papers, we studied sortable elements in finite Coxeter groups, and the related Cambrian fans. We applied sortable elements and Cambrian fans to the study of cluster algebras of finite type and the noncrossing partitions associated to Artin groups of finite type. In this paper, as the first step towards expanding these applications beyond finite type, we study sortable elements in a general Coxeter group W. We supply uniform arguments which transform all previous finite-type proofs into uniform proofs (rather than type by type proofs), generalize many of the finite-type results and prove new and more refined results. The key tools in our proofs include a skew-symmetric form related to (a generalization of) the Euler form of quiver theory and the projection \pidown^c mapping each element of W to the unique maximal c-sortable element below it in the weak order. The fibers of \pidown^c essentially define the c-Cambrian fan. The most fundamental results are, first, a precise statement of how sortable elements transform under (BGP) reflection functors and second, a precise description of the fibers of \pidown^c. These fundamental results and others lead to further results on the lattice theory and geometry of Cambrian (semi)lattices and Cambrian fans.
Frameworks With Crystallographic Symmetry

Periodic frameworks with crystallographic symmetry are investigated from the perspective of a general deformation theory of periodic bar-and-joint structures in Euclidean spaces of arbitrary dimension. It is shown that natural parametrizations provide affine section descriptions for families of frameworks with a specified graph and symmetry. A simple geometrical setting for displacive phase transitions is obtained. Upper bounds are derived for the number of realizations of minimally rigid periodic graphs.
Hygrothermomechanical Evaluation of Transverse Filament Tape Epoxy/Polyester Fiberglass Composites

Transverse filament tape (TFT) fiberglass/epoxy and TFT polyester composites intended for low cost wind turbine blade fabrication have been subjected to static and cyclic load behavior tests whose results are presently evaluated on the basis of an integrated hygrothermomechanical response theory. Laminate testing employed simulated filament winding procedures. The results obtained show that the predicted hygrothermomechanical environmental effects on TFT composites are in good agreement with measured data for various properties, including fatigue at different R-ratio values.
On the sources and significance of interindustry differences in technological opportunities

Abstract The set of technological opportunities in a given industry is one of the fundamental determinants of technical advance in that line of business. We examine the concept of technological opportunity and discuss three categories of sources of those opportunities: advances in scientific understanding and technique, technological advances originating in other industries and in other private and governmental institutions, and feedbacks from an industry's own technological advances. Data from the Yale Survey on Industrial Research and Development are used to measure the strength of various sources of technological opportunity and to discern interindustry differences in the importance of these sources. We find that interindustry differences in the strength and sources of technological opportunities contribute importantly to explanations of cross-industry variation in R&D intensity and technological advance.
A large statistics study of the performance and yields of generation-6 VLPCs (HISTE-VI)

In this paper, the D0 collaboration reports on the test results of 142 880 VLPC pixels. The authors have explored the space of operating conditions and find good performance at a temperature of 9 K and an average bias voltage of 7 V. Preliminary tests have shown an average quantum efficiency of 80% and a gain of 20 000 -- 60 000. Tests have shown that the devices can be made to work at very high rates. The pixel-to-pixel variation within a chip is manageable, allowing one to assemble like-performing VLPC chips into cassettes containing 1024 pixels each.
Analysis of sub-micron mineral matter in coal via scanning transmission electron microscopy

The fine-scale mineral matter in three US coals has been analyzed via scanning transmission electron microscopy (STEM). The samples observed were a North Dakota lignite, a Kentucky bituminous, and a Pennsylvania anthracite. Specific mineral types, differing among the three coals examined, appear to predominate at this fine size scale (particles less than or equal to 200nm in diameter). Fe-rich and Ba-rich minerals in the lignite, a Ti-rich mineral in the bituminous, and Ca-rich and Ti-rich minerals in the anthracite were the predominant species found. The inherent mineral content in the observed organic background also differs from coal to coal. The distributions of mineral species in the size range less than or equal to 200nm reported herein do not reflect the distributions in the larger size ranges obtained by more macroscopic techniques.
Knotted Spheres and Graphs in Balls

Given a properly embedded graph Γ in a ball B and a punctured sphere Σ properly embedded in B-Γ we examine the conditions on Γ that are necessary to assure that Σ is boundary parallel.
NUT midline carcinoma

NUT midline carcinoma, a squamous cell carcinoma, is one of the most aggressive human cancers, and there is a desperate need for effective therapies for patients with this disease. Will the new bromodomain and extra terminal (BET) inhibitors prove to be one such treatment for this rare and enigmatic cancer?
Far-infrared variability in active galactic nuclei

Pointed IRAS observations of 20 active galaxies were examined in the first detailed search for far-infrared variability in a large sample of active galaxies. Less extensive survey data were also checked for evidence of strong 6-month variability in 45 active galaxies. The far-infrared fluxes of three highly polarized objects ('blazars') appeared to vary by up to a factor of 2 on time scales of a few months. No convincing cases of variability greater than about 15 percent (rms) were found in any of the normal quasars or Seyfert galaxies studied. It appears that blazars tend to be variable at all wavelengths, but most active galaxies may be systematically less variable in the far-infrared than at higher frequencies.
Higgs constraints from vector boson fusion and scattering

We present results on 4-lepton + 2-jet production, the partonic processes most commonly described as vector boson pair production in the Vector Boson Fusion (VBF) mode. This final state contains diagrams that are mediated by Higgs boson exchange. We focus particularly on the high-mass behaviour of the Higgs boson mediated diagrams, which unlike on-shell production, gives information about the Higgs couplings without assumptions on the Higgs boson total width. We assess the sensitivity of the high-mass region to Higgs coupling strengths, considering all vector boson pair channels, W−W+, W±W±, W±Z and ZZ. Because of the small background, the most promising mode is W+W+ which has sensitivity to Higgs couplings because of Higgs boson exchange in the t-channel. Using the Caola-Melnikov (CM) method, the off-shell couplings can be interpreted as bounds on the Higgs boson total width. We estimate the bound that can be obtained with current data, as well as the bounds that could be obtained at $$ \sqrt{s}=13 $$ TeV in the VBF channel for data samples of 100 and 300 fb−1. The CM method has already been successfully applied in the gluon fusion (GGF) production channel. The VBF production channel gives important complementary information, because both production and decay of the Higgs boson occur already at tree graph level.
Stochastic belief propagation: Low-complexity message-passing with guarantees

The sum-product or belief propagation (BP) algorithm is widely used to compute exact or approximate marginals in graphical models. However, for graphical models with continuous or high-dimensional discrete states and/or high degree factors, it can be computationally expensive to update messages. We propose the stochastic belief propagation algorithm (SBP) as a low-complexity alternative. It is a randomized variant of BP that passes only stochastically chosen information at each round, thereby reducing the complexity per iteration by an order of magnitude. We prove that it enjoys a number of rigorous convergence guarantees: for any tree-structured graph, the SBP updates converge almost surely to the BP fixed point, and we provide non-asymptotic bounds on the mean absolute error. For general graphs that satisfy a standard contraction condition, we establish almost sure convergence to the unique BP fixed point, as well as non-asymptotic guarantees on the mean squared error, showing that it decays as 1/t with the number of iterations t. We also provide high probability bounds on the actual error.
Spatial correlation of transionospheric signal time delays

Excess time delays of transionospheric radio signals introduce ranging errors in satellite-navigation and radar systems, which are directly proportional to the total electron content (TEC) along the propagation path. Correlation between TEC at Fort Monmouth, NJ ( 40.18\deg N, 74.06\deg W) and Richmond, FL ( 25.60\deg N, 80.40\deg W) was determined. The correlation analysis was performed at monthly and daily intervals for the equinoctial and winter periods during the quiet phase of the solar cycle. Positive maxima of monthly correlation coefficients were \gsim 0.9 for data comparisons at identical or nearly identical times, and decreased when the data sets were shifted in time with respect to each other. Positive maxima of daily correlation coefficients were, in general, \gsim 0.9 . Seasonal variations were noticeable.
A generalization of the endogenous grid method

Abstract This paper extends Carroll's [2005. The method of endogenous gridpoints for solving dynamic stochastic optimization problems. National Bureau of Economic Research Technical Working Paper 309]. endogenous grid method to perform value function iteration in models with more than one control variable. We propose to mix the endogenous grid method with standard value function iteration to achieve higher efficiency. We illustrate the method using the stochastic neoclassical growth model with and without labor–leisure choice. We report important gains in efficiency that make value function iteration an attractive computational method in terms of both computing time and accuracy.
The effect of scaling on the performance of elastomer composite actuators

Compact actuation that is integrated into a structure's material system has the potential to provide rapid structural reconfiguration while reducing weight. The effect of scale (diameter, overall length and segment length) on the performance of cylindrical fiber-reinforced McKibben-like Rubber Muscle Actuators (RMA) was investigated. An "activation" pressure was observed for all actuators at a value that depended upon the actuation construction. Upon pressurization past the activation threshold, the overall force, stroke, and work capacity increased with increasing actuation length and diameter. The actuation force per unit RMA cross-sectional area was predicted, and experimentally observed, to be roughly constant after activation. By segmenting a longer actuator, a larger contraction and lower actuation force could be achieved. Though actuation forces decreased as actuator diameter and length decreased, the force per unit actuator volume was shown to increase with decreasing diameter including a roughly 4-fold increase in force/volume between the 0.5" and 0.05" actuators. However, due to the small amount of total contraction for the smaller diameter actuators, the relative work per actuation volume was decreased by roughly 35% in comparing those same actuators. Thus, small diameter RMAs have great potential to provide needed linear actuation force within adaptive material systems.
Buckminsterfullerene C60 and organic ferromagnetism

Abstract Interest in the electronic properties of C60 led to the discovery of metals, superconductors and a solid with a transition to a magnetic state. The approaches to organic ferromagnets are reviewed briefly, with emphasis on the McConnell model. The review is followed by the description of the magnetic properties of C60 TDAE at ambient pressure and under hydrostatic pressure, showing that the 16 K transition is extremely pressure sensitive and that the effect of pressure is reversible. An explanation of the properties of C60 TDAE in terms of a modification of the McConnell model is described for the first time.
What Is the Neon Abundance of the Sun

We have evolved a series of 13 complete solar models that utilize different assumed heavy-element compositions. Models that are based upon the heavy-element abundances recently determined by Asplund and coworkers are inconsistent with helioseismological measurements. However, models in which the neon abundance is increased by 0.4-0.5 dex to log N(Ne) = 8.29 ± 0.05 [on the scale in which log N(H) = 12] are consistent with the helioseismological measurements even though the other heavy-element abundances are in agreement with the determinations of Asplund et al. These results sharpen and strengthen an earlier study by Antia & Basu. The predicted solar neutrino fluxes are affected by the uncertainties in the composition by less than their 1 σ theoretical uncertainties.
Learning Conjunctions of Horn Clauses

An algorithm is presented for learning the class of Boolean formulas that are expressible as conjunctions of Horn clauses. (A Horn clause is a disjunction of literals, all but at most one of which is a negated variable.) The algorithm uses equivalence queries and membership queries to produce a formula that is logically equivalent to the unknown formula to be learned. The amount of time used by the algorithm is polynomial in the number of variables and the number of clauses in the unknown formula.
Contributions of Public and Private Science and Technology to U.S. Agricultural Productivity

The impact of public and private research to agricultural productivity in the US between 1950 and 1982 were assessed using an econometric model. Analysis of US aggregate measures of multifactor agricultural productivity was undertaken using imputation-accounting, statistical meta-function and statistical productivity decomposition methods. The study indicated that public sector research should be focused on general and pretechnology sciences while private sector resources should be channeled to applied research and technology advancement.
Simplified procedures for designing adhesively bonded composite joints

Procedures for the preliminary design for composite adhesive joints are described. Typical joints, their respective free body diagrams, and approximate equations for estimating the stresses in each of these typical joints are summarized. Equations are also presented to check the critical conditions of the joint such as minimum length, maximum adhesive shear stress, and peel-off stress. To illustrate the procedure, sample designs are described in step-by-step fashion for a butt joint with single doubler subjected to static loads, cyclic loads, and environmental effects. The results show that unsymmetric adhesive joints are inefficient and should be avoided, and hygrothermal environments and cyclic loads dramatically reduce the structural integrity of the joint and require several joint lengths compared with those for static load with no environmental effects.
Market Transparency: Who Wins and Who Loses?

This study uses laboratory experiments to determine the effects of trade and quote disclosure on market efficiency, bid-ask spreads, and trader welfare. We show that trade disclosure increases the informational efficiency of transaction prices, but also increases opening bid-ask spreads, apparently by reducing market-makers' incentives to compete for order flow. As a result, trade disclosure benefits market makers at the expense of liquidity traders and informed traders. We find that quote disclosure has no discernible effects on market performance. Overall our results demonstrate that the degree of market transparency has important effects of market equilibria and on trader and market-maker welfare. Article published by Oxford University Press on behalf of the Society for Financial Studies in its journal, The Review of Financial Studies.
Time-domain simulation of acoustic propagation in a lined duct

Abstract An inviscid, spatial time-domain numerical simulation is employed to compute acoustic wave propagation in a duct treated with an acoustic liner. The motivation is to assess the effects on sound attenuation of bias flow passed through the liner for application to noise suppression in jet engine nacelles. Physically, the liner is composed of porous sheets with backing air cavities. The mathematical model lumps the sheets' presence into a continuous empirical source term which modifies the right-hand side of the momentum equations. This source term specifies the time-domain characteristics of the frequency-domain resistance and reactance of the liner's component sheets. Nonlinear behavior of the liner sheets at high sound pressure levels is included in the form of the source term. The source term constants are empirically matched to frequency-domain impedance data via a one-dimensional numerical impedance tube simulation. The resulting liner model is then incorporated into a two-dimensional Euler solver and used for simulations of a realistic duct configuration. Sound pressure levels and axially transmitted power are computed to assess the attenuation effects of various magnitudes of bias flow. Simulation results are compared to available experimental data from a geometrically similar lined duct.
Investigation of polymer and surfactant-polymer injections in South Slattery Minnelusa Reservoir, Wyoming

This paper presents an investigation of the enhanced oil recovery (EOR) potential in the South Slattery Minnelusa formation. The South Slattery Field, which is characterized by low permeability and high saline brine, is stepping into the economic limits of secondary waterflood. A chemical flooding simulation model which was based on experimental parameters was set up for the potential investigation of EOR. Both polymer and surfactant-polymer floods were investigated. The recoveries of these EOR methods are presented, and the development efficiencies are analyzed.
The effect of interburst intervals on measures of hippocampal LTP in the freely moving adult male rat.

An important factor in the induction and maintenance of long-term potentiation (LTP) is the tetanization paradigm. This paper presents the changes associated with the induction and maintenance of hippocampal LTP in the freely moving adult male rat, subjected to three different tetanization paradigms. These results indicate that specific LTP measures including (1) synaptic activation, as measured by the slope of the dentate granule cell population excitatory postsynaptic potential, and (2) cellular response, as measured by the dentate population spike amplitude, evoked by single-pulse stimulation of the medial perforant pathway are dependent on the interburst interval of the bursting paradigm commonly used in LTP studies.
Extending planar graph algorithms to K 3,3 -free graphs

For several problems, restricting attention to special classes of graphs has yielded better algorithms. In particular, restricting to planar graphs yields efficient parallel algorithms for several graph problems. In this paper we extend these algorithms to K3,3-free graphs, showing that the restriction of planarity is not important. The three problems dealt with are : graph coloring, depth first search and maximal independent sets. As a corollary we show that K3,3-free graphs are five colorable (this bound is tight).
Superlinear Lower Bounds for Bounded-Width Branching Programs

We use algebraic techniques to obtain superlinear lower bounds on the size of bounded-width branching programs to solve a number of problems. In particular, we show that any bounded-width branching program computing a nonconstant threshold function has length ?(n log log n), improving on the previous lower bounds known to apply to all such threshold functions. We also show that any program over a finite solvable monoid computing a product in a nonsolvable group has length ?(n log log n). This result is a step toward proving the conjecture that the circuit complexity class ACC0 is properly contained in NC1.
Use of silane-methane mixtures for scramjet ignition

Calculations have been made to demonstrate the use of silane-methan e liquid mixtures as an ignition promoter and flame stabilizer in hydrogen- (or other) fueled scramjet applications. The calculations show that mixtures initially nonflammable undergo rapid methane evaporation to produce drops capable of spontaneous inflammation. This technique may be expanded to other spontaneously flammable materials. It was assumed that the liquid silane-methane mixture was sprayed into the combijstion chamber upstream of the main fuelflow positions. Drop size, flow velocity, temperature, and initial liquid mixture composition were varied.
Semistable reduction for overconvergent $F$-isocrystals I: Unipotence and logarithmic extensions

Let whose complement is a strict normal crossings divisor. We also obtain some related results, including a form of Zariski–Nagata purity for isocrystals.
The Injective Spectrum of a Noncommutative Space

Abstract For a noncommutative space X , we study Inj( X ), the set of isomorphism classes of indecomposable injective X -modules. In particular, we look at how this set, suitably topologized, can be viewed as an underlying “spectrum” for X . As applications we discuss noncommutative notions of irreducibility and integrality, and a way of associating an integral subspace of X to each element of Inj( X ) which behaves like a “weak point.”
Noetherianity of the space of irreducible representations

LetR be an associative ring with identity. We study an elementary generalization of the classical Zariski topology, applied to the set of isomorphism classes of simple leftR-modules (or, more generally, simple objects in a complete abelian category). Under this topology the points are closed, and whenR is left noetherian the corresponding topological space is noetherian. IfR is commutative (or PI, or FBN) the corresponding topological space is naturally homeomorphic to the maximal spectrum, equipped with the Zariski topology. WhenR is the first Weyl algebra (in characteristic zero) we obtain a one-dimensional irreducible noetherian topological space. Comparisons with topologies induced from those on A. L. Rosenberg’s spectra are briefly noted.
Steady-State Analysis of a Nonlinear Rotor-Housing System

The periodic steady state response of a high pressure oxygen turbopump (HBOTP) of a Space Shuttle main engine (SSME), involving a clearance between the bearing and housing carrier, is sought. A harmonic balance method utilizig Fast Fourier Transform (FFT) algorithm is developed for the analysis. An impedance method is used to reduce the number of degrees of freedom to the displacements at the bearing clearance. Harmonic and subharmonic responses to imbalance for various system parameters are studied. The results show that the computational technique developed in this study is an effective and flexible method for determining the stable and unstable periodic response of complex rotor-housing systems with clearance type nonlinearity.
FaceID:a face detection and recognition system

A face detection system that automatically locates faces in gray-level images is described. Also described is a system which matches a given face image with faces in a database. Face detection in an image is performed by template matching using templates derived from a selected set of normalized faces. Instead of using original gray level images, vertical gradient images were calculated and used to make the system more robust against variations in lighting conditions and skin color. Faces of different sizes are detected by processing the image at several scales. Further, a coarse- to-fine strategy is used to speed up the processing, and a combination of whole face and face component templates are used to ensure low false detection rates. The input to the face recognition system is a normalized vertical gradient image of a face, which is compared against a database using a set of pretrained feedforward neural networks with a winner-take-all fuser. The training is performed by using an adaptation of the backpropagation algorithm. This system has been developed and tested using images from the FERET database and a set of images obtained from Rowley, et al and Sung and Poggio.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Nonlinear particle acceleration in relativistic shocks

Abstract Monte Carlo techniques are used to model nonlinear particle acceleration in parallel collisionless shocks of various speeds, including mildly relativistic ones. When the acceleration is efficient, the backreaction of accelerated particles modifies the shock structure and causes the compression ratio, r, to increase above test-particle values. Modified shocks with Lorentz factors, γ0≲3, can have compression ratios considerably >3 and the momentum distribution of energetic particles no longer follows a power law relation. These results may be important for the interpretation of gamma-ray bursts if mildly relativistic internal and/or afterglow shocks play an important role accelerating particles that produce the observed radiation. For γ0≳10, r approaches 3 and the so-called ‘universal’ test-particle result of N(E)∝E−2.3 is obtained for sufficiently energetic particles. In all cases, the absolute normalization of the particle distribution follows directly from our model assumptions and is explicitly determined.
A multiscale modeling study for the convective mass transfer in a subsurface aquifer

Quantitative and realistic computer simulations of mass transfer associated with $$\hbox {CO}_2$$ disposal in subsurface aquifers is a challenging endeavor. This article has proposed a novel and efficient multiscale modeling framework, and has examined its potential to study the penetrative mass transfer in a $$\hbox {CO}_2$$ plume that migrates in an aquifer. Numerical simulations indicate that the migration of the injected $$\hbox {CO}_2$$ enhances the vorticity generation, and the dissolution of $$\hbox {CO}_2$$ has a strong effect on the natural convection mass transfer. The vorticity decays with the increase of the porosity. The time scale of the vertical migration of a $$\hbox {CO}_2$$ plume is strongly dependent on the rate of $$\hbox {CO}_2$$ dissolution. Comparisons confirm the near optimal performance of the proposed multiscale model. These primary results with an idealized computational model of the $$\hbox {CO}_2$$ migration in an aquifer brings the potential of the proposed multiscale model to the field of heat and mass transfer in the geoscience.
Inapproximability of maximal strip recovery

In comparative genomics, the first step of sequence analysis is usually to decompose two or more genomes into syntenic blocks that are segments of homologous chromosomes. For the reliable recovery of syntenic blocks, noise and ambiguities in the genomic maps need to be removed first. Maximal Strip Recovery (MSR) is an optimization problem proposed by Zheng, Zhu, and Sankoff for reliably recovering syntenic blocks from genomic maps in the midst of noise and ambiguities. Given d genomic maps as sequences of gene markers, the objective of MSR-d is to find d subsequences, one subsequence of each genomic map, such that the total length of syntenic blocks in these subsequences is maximized. For any constant d>=2, a polynomial-time 2d-approximation for MSR-d was previously known. In this paper, we show that for any d>=2, MSR-d is APX-hard, even for the most basic version of the problem in which all gene markers are distinct and appear in positive orientation in each genomic map. Moreover, we provide the first explicit lower bounds on approximating MSR-d for all d>=2. In particular, we show that MSR-d is NP-hard to approximate within @W(d/logd). From the other direction, we show that the previous 2d-approximation for MSR-d can be optimized into a polynomial-time algorithm even if d is not a constant but is part of the input. We then extend our inapproximability results to several related problems including CMSR-d, @d-gap-MSR-d, and @d-gap-CMSR-d.
Photon localization laser

We report the observation of random lasing based on photon localization in a random layered amplifying medium. Low-threshold lasing is facilitated by the overlap of long-lived localized modes at both the excitation and emission wavelengths.
Artificial intelligence research strategies in the light of AI models of scientific discovery

Some recent artificial intelligence programs whose task is to simulate the processes of scientific discovery can be taken as models of the history and processes of discovery within the Al discipline Itself. Consistently with these models, AI research relies basically on the methods of heuristic best-first search. Because of Its necessarily vague end open goals, it works forward inductively (rather than backward In menea-ends fashion), guided by a crude evaluation function that tests running programs to identify promising directions. AI reseerch Is empirical and pragmatic, typically working with examples rather than theorems, and exemplfyin the heuristic of learning by doing. In Its essential reliance on weak methods and experiment Insteed Of proof, it is edepted to the exploration of poorly structured task domains, showing considerable contrest In the respect to operetione reseerch or numerical analysis, which thrive best In domains possessing strong formal structure.
Ultra high energy cosmic ray neutrinos

Abstract Neutrinos, produced by the collisions of ultra high energy cosmic rays and the 3 K background radiation, require careful treatment of the evolving cosmic ray spectrum. The resulting neutrino differential energy spectrum is flat up to energies of order 10 19 eV, thus most events are expected at this energy. The total ν e -flux should be significantly larger than the proton flux at ∼5 × 10 19 eV when the recoil proton is correctly treated in photomeson production and when the Bethe-Heitler process (e + e − pair production) is incorporated. Based upon the observed primary proton spectrum we obtain a lower limit on the neutrino flux of ∼5.2/km 2 yr sr implying roughly 0.4 detected upward moving events per year in the present Fly's Eye range of sensitivity.
A comparison of nucleophilic reactions of 3-benzenesulfonyloxyalloxazine and its 1-methyl analog†

Reactions of 3-benzenesulfonyloxyalloxazine (1a) and its 1-methyl analog 1b with a number of nucleophilic reagents are reported. Relatively small nucleophiles, such as hydroxide ion, methanol, ethanol, methylamine, hydrazine and hydroxylamine converted 1a to 4-carboxy-s-triazolo[4,3-a]quinoxalin-1(2H)-ones and the corresponding esters or amides. As the size of the amine increased from methylamine to ethylamine, dimethylamine, propylamine and isopropylamine, there were obtained 4-(carboxamido)-s-triazolo[4,3-a]quin-oxalin-1(2H)-ones, (1-carboxamido)imidazolo[4,5-b]quinoxalines and 2,3-bis(ureido)quinoxalines. Sodium hydride or potassium cyanide in hot DMF degraded 1a to imidazolo[4,5-b]quinoxaline. However, methylmer-captide and benzylmercaptide ions attacked the sulfonate group of 1a to form 3-hydroxyalloxazine. 1-Methyl-3-benzenesulfonyloxyalloxazine (1b) reacted with methanol, ethanol, 1-propanol, and to some degree 2-propanol, in the presence of triethylamine to furnish anhydro-1-hydroxy-3-methyl-4-(alkoxycarbonyl)-s-triazolo[4,3-a]quinoxalinium hydroxides. However, sodium methoxide in methanol converted this starting material to a mixture of anhydro-1-hydroxy-3-methyl-s-triazolo[4,3-a]quinoxalinium hydroxide and 1-methyl-3-hydroxyflavazole. A saturated aqueous solution of triethylamine transformed 1b to anhydro-1-hydroxy-3-methyl-s-triazolo[4,3-a]quinoxalinium hydroxide, apparently via the corresponding unstable 4-carboxylic acid. The reactions of 1b with a number of aliphatic amines yielded either amides based on the above mesoionic system or on the 3-carboxamido-2-quinoxalyl semicarbazide structure. The reaction of 1b with potassium cyanide furnished 1-methylimidazolo[4,5-b]quinoxaline. Mechanisms to explain all of the degradations are advanced.
Can Extra Updates Delay Mixing

We consider Glauber dynamics (starting from an extremal configuration) in a monotone spin system, and show that interjecting extra updates cannot increase the expected Hamming distance or the total variation distance to the stationary distribution. We deduce that for monotone Markov random fields, when block dynamics contracts a Hamming metric, single-site dynamics mixes in O(n log n) steps on an n-vertex graph. In particular, our result completes work of Kenyon, Mossel and Peres concerning Glauber dynamics for the Ising model on trees. Our approach also shows that on bipartite graphs, alternating updates systematically between odd and even vertices cannot improve the mixing time by more than a factor of log n compared to updates at uniform random locations on an n-vertex graph. Our result is especially effective in comparing block and single-site dynamics; it has already been used in works of Martinelli, Toninelli, Sinclair, Mossel, Sly, Ding, Lubetzky, and Peres in various combinations.
The Effect of Body Mass Index on the Outcomes of Varicocelectomy

Purpose: Obesity is recognized as a potential contributor to male factor infertility. There are no studies to date to our knowledge that have examined the success of varicocelectomy in obese men. We determined if body mass index significantly affects the outcome of varicocelectomy.Materials and Methods: Retrospective chart review was performed for all patients who underwent varicocelectomy from September 2003 to December 2009. Patients were placed into 3 groups based on body mass index, and categorized as normal weight (group 1—38 patients, body mass index 18.5 to 24.9), overweight (group 2—59 patients, body mass index 25 to 29.9) or obese (group 3—46 patients, body mass index 30 or greater). Significant improvement was defined as a greater than 50% increase in the total motile per ejaculate parameter on postoperative semen analysis.Results: A total of 143 patients were available for analysis. There were no significant differences among patients in the 3 groups except for body mass index. Significant impr...
The Production of Rotational and Vibrational Transitions in Encounters between Molecules

Publisher Summary This chapter focuses on the production of rotational and vibrational transitions in molecular encounters. Vibrational transitions are infrequent in most diatomic gases at or below room temperature, so that the distorted wave method provides reliable results. However, they may be affected considerably by rotational transitions as these increase or decrease the change in the translational energy. Furthermore, the relative orientation of the colliding molecules influences the vibrational transition probabilities. After a series of rotational transitions, the molecules may tend to have a particular relative orientation at the instant of the vibrational transition. Rotational transitions must be studied in detail before vibrational transitions can be treated. If the duration of the encounter is longer than the period of molecular rotation and vibration, and the distortion is nearly adiabatic, there is another appropriate set of basic functions sometimes used in the treatment of atomic collisions—the perturbed stationary state (PSS) wave functions. Unless the energy of relative motion is high, PSS functions provide a good basis for treating rotational transitions in collisions between strongly polar molecules, vibrational transitions of a molecule with a small force constant, and both rotational and vibrational transitions in collisions between chemically reactive molecule.
Efficient intramolecular hydroalkoxylation/cyclization of unactivated alkenols mediated by lanthanide triflate ionic liquids.

Lanthanide triflates, Ln(OTf)3, serve as efficient catalysts for the intramolecular hydroalkoxylation (HO)/cyclization of primary/secondary and aliphatic/aromatic hydroxyalkenes in room temperature ionic liquids (RTILs). Cyclizations are effective in the formation of five- and six-membered oxygen heterocycles with Markovnikov-type selectivity. Reaction rates exhibit first-order dependence on [Ln3+] and [substrate].
Support for Distributed Transactions in the TABS Prototype

The TABS prototype is an experimental facility that provides operating system-level support for distributed transactions that operate on shared abstract types. The facility is designed to simplify the construction of highly available and reliable distributed applications. This paper describes the TABS system model, the TABS prototype's structure, and certain aspects of its operation. The paper concludes with a discussion of the status of the project and a preliminary evaluation.
Phase transitions in dissipative quantum transport and mesoscopic nuclear spin pumping

Topological phase transitions can occur in the dissipative dynamics of a quantum system when the ratio of matrix elements for competing transport channels is varied. Here we establish a relation between such behavior in a class of non-Hermitian quantum walk problems [M. S. Rudner and L. S. Levitov, Phys. Rev. Lett. 102, 065703 (2009)] and nuclear spin pumping in double quantum dots, which is mediated by the decay of a spin-blockaded electron triplet state in the presence of spin-orbit and hyperfine interactions. The transition occurs when the strength of spin-orbit coupling exceeds the strength of the net hyperfine coupling and results in the complete suppression of nuclear spin pumping. Below the transition point, nuclear pumping is accompanied by a strong reduction in current due to the presence of nondecaying ``dark states'' in this regime. Due to its topological character, the transition is expected to be robust against dephasing of the electronic degrees of freedom.