cssi/SciSciGPT-SciSciNet huggingface dataset:
Diesel engine dynamometer testing of impedancemetric NOx sensors

Abstract Prototype solid-state electrochemical sensors using a dense gold sensing electrode, porous yttria-stabilized zirconia (YSZ) electrolyte, and a platinum counter electrode (Au/YSZ/Pt) were evaluated for measuring NOx (NO and NO2) in diesel exhaust. Both electrodes were exposed to the test gas (i.e., there was no reference gas for the counter electrode). An impedancemetric method was used for NOx measurements, where the phase angle was used as the response signal. A portion of the tailpipe exhaust from the dynamometer test stand was extracted and fed into a furnace containing the experimental sensor. The prototype sensor was tested along with a commercially available NOx sensor. Simultaneous measurements for NOx, O2, CO2, H2O, CO, and CH4 in a separate feed stream were made using Fourier transform infrared (FTIR) spectroscopy and an oxygen paramagnetic analyzer. The experimental sensor showed very good measurement capability for NO in the range of 25–250 ppm, with a response paralleling that of the FTIR and commercial sensor. The prototype sensor showed better sensitivity to NOx at the lower concentration ranges. O2 is an interferent for the experimental sensor, resulting in decreased sensitivity for measurement of NOx. Methods to overcome this interference are discussed.
Carbene-stabilized main group radicals and radical ions

Shortly after their discovery at the end of the 80s, stable singlet carbenes have been recognized as excellent ligands for transition metal based catalysts, and as organo-catalysts in their own right. At the end of the 2000s, it has been shown that they can coordinate main group elements in their zero oxidation state, and even activate small molecules. This review covers examples in the literature dealing with the most recent application of stable singlet carbenes, namely their use to stabilize radicals and radical ions that are otherwise unstable.
Dissociating markers of senescence and protective ability in memory T cells.

No unique transcription factor or biomarker has been identified to reliably distinguish effector from memory T cells. Instead a set of surface markers including IL-7Rα and KLRG1 is commonly used to predict the potential of CD8 effector T cells to differentiate into memory cells. Similarly, these surface markers together with the tumor necrosis factor family member CD27 are frequently used to predict a memory T cell's ability to mount a recall response. Expression of these markers changes every time a memory cell is stimulated and repeated stimulation can lead to T cell senescence and loss of memory T cell responsiveness. This is a concern for prime–boost vaccine strategies which repeatedly stimulate T cells with the aim of increasing memory T cell frequency. The molecular cues that cause senescence are still unknown, but cell division history is likely to play a major role. We sought to dissect the roles of inflammation and cell division history in developing T cell senescence and their impact on the expression pattern of commonly used markers of senescence. We developed a system that allows priming of CD8 T cells with minimal inflammation and without acquisition of maximal effector function, such as granzyme expression, but a cell division history similar to priming with systemic inflammation. Memory cells derived from minimal effector T cells are fully functional upon rechallenge, have full access to non-lymphoid tissue and appear to be less senescent by phenotype upon rechallenge. However, we report here that these currently used biomarkers to measure senescence do not predict proliferative potential or protective ability, but merely reflect initial priming conditions.
Multi-magnon luminescence sidebands in antiferromagnets

Abstract Using pulsed excitation and detection, we have observed multi-magnon (⩽ 7) luminescence sidebands of the 4 T 1g ( 4 G) → 6 A 1g ( 6 S) excitonic transition in MnF 2 , KMnF 3 , and RbMnF 3 . A simple model is proposed to explain the results qualitatively.
M-theory and E10: billiards, branes, and imaginary roots

Eleven dimensional supergravity compactified on $T^10$ admits classical solutions describing what is known as billiard cosmology - a dynamics expressible as an abstract (billiard) ball moving in the 10-dimensional root space of the infinite dimensional Lie algebra E10, occasionally bouncing off walls in that space. Unlike finite dimensional Lie algebras, E10 has negative and zero norm roots, in addition to the positive norm roots. The walls above are related to physical fluxes that, in turn, are related to positive norm roots (called real roots) of E10. We propose that zero and negative norm roots, called imaginary roots, are related to physical branes. Adding 'matter' to the billiard cosmology corresponds to adding potential terms associated to imaginary roots. The, as yet, mysterious relation between E10 and M-theory on $T^10$ can now be expanded as follows: real roots correspond to fluxes or instantons, and imaginary roots correspond to particles and branes (in the cases we checked). Interactions between fluxes and branes and between branes and branes are classified according to the inner product of the corresponding roots (again in the cases we checked). We conclude with a discussion of an effective Hamiltonian description that captures some features of M-theory on $T^10.$
Gauge theory origins of supergravity causal structure

We discuss the gauge theory mechanisms which are responsible for the causal structure of the dual supergravity. For D-brane probes we show that the light cone structure and Killing horizons of supergravity emerge dynamically. They are associated with the appearance of new light degrees of freedom in the gauge theory, which we explicitly identify. This provides a picture of physics at the horizon of a black hole as seen by a D-brane probe.
Efficient preparations of novel ynamides and allenamides

Abstract Practical syntheses of a series of novel ynamides and allenamides are described here. While a base-induced isomerization protocol of propargyl amides leads to an array of chiral and achiral allenamides, ynamides are prepared from enamides via bromination followed by base-induced elimination of the Z -bromoenamides. These ynamides and allenamides possess improved thermal stability compared to ynamines and allenamines. They can be isolated, purified, and handled with ease, and thus, should be synthetically more useful than traditional ynamines and allenamines.
Experimental investigation and thermodynamic modeling of the Gd–Si system

Abstract The Gd–Si system has been investigated via experiments and thermodynamic modeling. In the experimental part, alloys were prepared by arc melting pure Gd and Si slugs and annealing at high temperature. The annealed alloys were then investigated by thermal analysis, X-ray diffraction and scanning electron microscopy. Except for the compound with AlB 2 structure, the existence of all other compounds was confirmed. In our study, instead of Gd 2 Si 3 , the compound with AlB 2 structure was found to be Gd 3 Si 5 . Although most of the reported invariant reaction temperatures are in good agreement with the present data, the convex liquidus in the composition range of 55–65 at.% Si was not found. The available phase equilibrium and thermodynamic data for the Gd–Si system were used in optimization of thermodynamic parameters by WinPhad software. The calculated phase equilibria and thermodynamic properties were compared to the corresponding experimental data and good agreement was found.
Laparoscopic approach to common duct pathology

The author reviews his experience with the laparoscopic management of common duct pathology and compares it with the experience of others as reported in the literature. Routine intraoperative cholangiography is advocated. A variety of methods of managing common duct stones laparoscopically is presented. These include balloon-catheter manipulation, fluoroscopically guided basket extraction, and choledochoscopic evaluation and removal of stones. The accumulated experience indicates that more than 90% of common duct stones can be removed laparoscopically via the cystic duct. This approach significantly reduces the need for either preoperative or postoperative endoscopic retrograde cholangiopancreatography. Although laparoscopic choledochotomy has been employed in a number of cases and can be performed with a high degree of safety and efficacy, it is needed only infrequently. This form of management results in decreased dependence upon T-tubes, thereby reducing postoperative morbidity and the length of hospitalization. A rational protocol for the management of common duct pathology is presented.
Technical change, input substitution and the specification of dynamic factor demands

Abstract Based on duality relationships for infinite horizon control problems, this paper develops and discusses a theoretical framework that allows technical change to be incorporated consistently into a system of dynamic factor demands. Two estimable models are derived based on the alternative assumptions of static technology expectations and expected continuous technical change. The empirical implications of the models are demonstrated by specifying a parametric model and then deriving the implied investment, variable factor, and supply system, and the associated profit maximizing and cost minimizing price elasticities. Whe the structure of the production technology is not directly known or observable, the dynamic duality approach provides an indirect method for analysing investment behaviour and the characteristics of the technology.
Novel dodecaarylporphyrins: synthesis and dynamic properties

Abstract An investigation of the synthesis of dodecaarylporphyrins using the Suzuki coupling reaction of arylboronic acids with octabromotetraarylporphyrins is reported. Variable temperature 1 H NMR studies of these new porphyrins reveal several dynamic processes including the first examples of β-aryl rotation.
D-branes, holonomy and M-theory

Abstract We show that M-theory on spaces with irreducible holonomy represent Type IIA backgrounds in which a collection of D6-branes wrap a supersymmetric cycle in a manifold with a holonomy group different from the one appearing in the M-theory description. For example, we show that D6-branes wrapping a supersymmetric four-cycle on a manifold with G2 holonomy is described in eleven dimensions by M-theory on a space with Spin(7) holonomy. Examples of such Type IIA backgrounds which lift to M-theory on spaces with SU(3), G2, SU(4) and Spin(7) holonomy are considered. The M-theory geometry can then be used to compute exact quantities of the gauge theory on the corresponding D-brane configuration.
Order dependency in the relational model

Abstract The relational model is formally extended to include fixed orderings on attribute domains. A new constraint, called order dependency, is then introduced to incorporate semantic information involving these orderings. It is shown that this constraint can be applied to enhance the efficiency of an implemented database. The thrust of the paper is to study logical implication for order dependency. The main theoretical results consist in (i) introducing a formalism analogous to propositional calculus for analyzing order dependency, (ii) exhibiting a sound and complete set of inference rules for order dependency, and (iii) demonstrating that determining logical implication for order dependency is co-NP-complete. It is also shown that there are sets of order dependencies for which no Armstrong relations exist.
Sensor-based planning: Exact cellular decompositions in terms of critical points

A coverage path planning algorithm produces a path that directs a robot (or its detector range, occupied volume, etc.) to sweep out a target volume. The goal of this work is to direct an agent to cover (fill) an unknown space using different coverage patterns. We achieve coverage by dividing the target region into sub-regions, termed cells, such that coverage in each cell can be accomplished by basic maneuvers, such as simple back-and-forth motions. This approach to coverage employs a representation of the free space called an exact cellular decomposition, which already has been widely used for path planning between two points. In this paper, we define exact cellular decompositions where critical points of Morse functions indicate the locations of cell boundaries. Morse functions are those whose critical points are non-degenerate. Different Morse functions induce different coverage patterns. Between critical points, the structure of a Morse function is effectively the same, so simple control laws to achieve tasks, such as coverage, are feasible within each cell. This paper addresses the issue of how to cover a space with varying patterns, but it also suggests a common framework for many conventional path planners. A companion paper describes the sensor based implementation of this approach.
Computer Simulation of Collective Ion Acceleration by Discrete Cyclotron Modes

Extensive analytical studies suggest that significant currents of high energy ions can be obtained by collective acceleration via large amplitude cyclotron waves in a non-neutral intense relativistic electron beam. We have already demonstrated this acceleration mechanism in fully self-consistent two-dimensional computer simulations for low ion current and energy. However, the simulations employed a packet of cyclotron waves created ad hoc upstream of the acceleration region. Acceleration was limited by phase-mixing and damping of the packet. Here, we shall present results of our ongoing effort to simulate, first, realistic growth of large amplitude, single frequency cyclotron waves in the relativistic electron beam and, second, acceleration of various ion currents with those waves.
Combinatorial Laws for Physically Meaningful Design

A typical computer representation of a design includes geometric and physical information organized in a suitable combinatorial data structure. Queries and transformations of these design representations are used to formulate most algorithms in computational design, including analysis, optimization, evolution, generation, and synthesis. Formal properties, and in particular existence and validity of the computed solutions, must be assured and preserved by all such algorithms. Using tools from algebraic topology, we show that a small set of the usual combinatorial operators: boundary (∂), coboundary (δ), and dualization (*) — are sufficient to represent a variety of physical laws and invariants. Specific examples include geometric integrity, balance and equilibrium, and surface smoothing. Our findings point a way toward systematic development of data structures and algorithms for design in a common formal computational framework.© 2003 ASME
Ising expansion for the Hubbard model.

We develop series expansions for the ground state properties of the Hubbard model by introducing an Ising anisotropy into the Hamiltonian. For the two-dimensional square lattice half-filled Hubbard model, the ground state energy, local moment, sublattice magnetization, uniform magnetic susceptibility, and spin stiffness are calculated as a function of U/t, where U is the Coulomb constant and t is the hopping parameter. Magnetic susceptibility data indicate a crossover around U\ensuremath{\approxeq}4 between spin density wave antiferromagnetism and Heisenberg antiferromagnetism. Comparisons with Monte Carlo simulations, random phase approximation result, and mean-field solutions are also made.
Equilibrium Phases Between Lithium Sulfide and Iron Sulfides

The equilibrium phases in the lithium sulfide--ferrous sulfide system were determined by differential thermal analysis and x-ray diffraction analysis. A compound, Li/sub 2/S--FeS, which melts incongruently at 885/sup 0/ +- 5/sup 0/C to Li/sub 2/S and a liquid containing approximately 50.5 mole percent (M/O) FeS, and has a transition at 840/sup 0/ +- 5/sup 0/C, was found. A eutectic between Li/sub 2/S.FeS and FeS was observed at 63 M/O FeS and 858/sup 0/ +- 3/sup 0/C. The terminal liquidus curves, computed by the application of Temkin's model, were found to be in good agreement with those experimentally determined. X-ray diffraction studies confirmed the transition in the compound Li/sub 2/S.FeS and also indicated compounds 2Li/sub 2/S.Fe/sub 3/S/sub 4/ and Li/sub 2/S.Fe/sub 2/S/sub 3/, between Li/sub 2/S, FeS, and FeS/sub 2/.
Flow over Plates with Suction through Porous Strips

This paper addresses the steady, incompressible, two-dimensional flow past a flat plate with suction through porous strips. Closed-form solutions for each flow quantity are developed in the context of linearized triple-deck theory using Fourier transforms. To demonstrate the validity of these closed-form solutions, we compare the wall shear stress and pressure coefficients and the streamwise velocity profiles from the linearized theory with those obtained by the numerical integration of both interacting and nonsimilar boundary-layer equations. The agreement between the linearized triple-deck and interacting boundary-layer equations is good; however, the nonsimilar boundary layers, which fail to account for upstream influence, are shown to be in poor agreement with both interacting boundary layers and the linearized triple deck. The linearized closed-form solutions will therefore be very useful in future stability calculations.
Star Formation at Zero and Very Low Metallicities

We describe how star formation is expected to proceed in the early metal‐free Universe, focusing on the very first generations of stars. We then discuss how the star formation process may change as the effects of metallicity, external radiative feedback, and magnetic and turbulent support of the gas become more important. The very first stars (Pop III. 1) have relatively simple initial conditions set by cosmology and the cooling properties of primordial gas. We describe the evolution of these stars as they grow in mass by accretion from their surrounding gas cores and how the accretion process is affected and eventually terminated by radiative feedback processes, especially H II region expansion and disk photoevaporation. The ability of the protostar and its disk to generate dynamically important magnetic fields is reviewed and their effects discussed. Pop III. 1 star formation is likely to produce massive (∼100–200M⊙) stars that then influence their surroundings via ionization, stellar winds, and superno...
Two-divisibility of the coefficients of certain weakly holomorphic modular forms

We study a canonical basis for spaces of weakly holomorphic modular forms of weights 12, 16, 18, 20, 22, and 26 on the full modular group. We prove a relation between the Fourier coefficients of modular forms in this canonical basis and a generalized Ramanujan τ-function, and use this to prove that these Fourier coefficients are often highly divisible by 2.
Improving asset performance through application of a structured decision process

Company experience, external benchmarking, and application of best practices all contribute to improved capital efficiency and reduced cycle time. Combining these practices with a value-driven decision structure yields a powerful method to advance a business opportunity from inception through completion. Many upstream petroleum companies are using, or developing, this type of method to improve reservoir characterization and development practices. Through direct experience in a variety of operational situations in the Gulf of Mexico, a five-step generic decision model evolved that is straightforward, intuitive, and scalable. The initial definitions of the opportunity, assessment of value, decision-makers, deliverables, and assignment of accountability to advance the opportunity to the next decision point are core to the project. The result is a customized road map from opportunity identification to post-implementation evaluation of results. Any business-process change within an active production operation is likely to meet organizational resistance. Unlike previous initiatives, however, this process has been well-received, primarily because it establishes a usable plan developed by the individuals directly responsible for advancing the business opportunity. We have been directly involved in a variety of applications, including complicated infrastructure retrofit projects, pipeline riser repairs, owner- and nonowner-operated development projects, well planning, and operation-support activities. The majority of applications are tangible, real-world situations that all operators routinely face. Each application contributed to the evolution of the model. Lessons learned are presented, including cases that illustrate and reinforce essential principles of the process. Conclusions, in the form of quantified financial and technical results, are also presented.
The importance of lens galaxy environments

It is suspected that many strong gravitational lens galaxies lie in poor groups or rich clusters of galaxies, which modify the lens potentials. Unfortunately, little is actually known about the environments of most lenses, so environmental effects in lens models are often unconstrained and sometimes ignored. We show that such poor knowledge of environments introduces significant biases and uncertainties into a variety of lensing applications. Specifically, we create a mock poor group of 13 galaxies that resembles real groups, generate a sample of mock lenses associated with each member galaxy, and then analyze the lenses with standard techniques. We find that standard models of two-image (double) lenses, which neglect environment, grossly overestimate both the ellipticity of the lens galaxy (Δe/e ~ 0.5) and the Hubble constant (Δh/h ~ 0.22). Standard models of four-image (quad) lenses, which approximate the environment as a tidal shear, recover the ellipticity reasonably well (|Δe/e| 0.24) but overestimate the Hubble constant (Δh/h ~ 0.15) and have significant (~30%) errors in the millilensing analyses used to constrain the amount of substructure in dark matter halos. For both doubles and quads, standard models slightly overestimate the velocity dispersion of the lens galaxy (Δσ/σ ~ 0.06) and underestimate the magnifications of the images (Δμ/μ ~ -0.25). Standard analyses that use the statistics of lens populations to place limits on the dark energy overestimate ΩΛ (by 0.05-0.14) and underestimate the ratio of quads to doubles (by a factor of 2). The systematic biases related to environment help explain some long-standing puzzles (such as the high observed quad/double ratio) but aggravate others (such as the low value of H0 inferred from lensing). Most of the biases are caused by neglect of the convergence (gravitational focusing) from the mass associated with the environment, but additional uncertainty is introduced by neglect of higher order terms in the lens potential. Fortunately, we show that directly observing and modeling lens environments should make it possible to remove the biases and reduce the uncertainties. Such sophisticated lensing analyses will require finding the other galaxies that are members of the lensing groups and measuring the group centroids and velocity dispersions, but they should reduce systematic effects associated with environments to the few percent level.
Development of safe and scalable continuous-flow methods for palladium-catalyzed aerobic oxidation reactions

The synthetic scope and utility of Pd-catalyzed aerobic oxidation reactions has advanced significantly over the past decade, and these reactions have the potential to address important green-chemistry challenges in the pharmaceutical industry. This potential has not been realized, however, because safety concerns and process constraints hinder large-scale applications of this chemistry. These limitations are addressed by the development of a continuous-flow tube reactor, which has been demonstrated on several scales in the aerobic oxidation of alcohols. Use of a dilute oxygen gas source (8% O2 in N2) ensures that the oxygen/organic mixture never enters the explosive regime, and efficient gas-liquid mixing in the reactor minimizes decomposition of the homogeneous catalyst into inactive Pd metal. These results provide the basis for large-scale implementation of palladium-catalyzed (and other) aerobic oxidation reactions for pharmaceutical synthesis.
Two-phase sampling experiment for propensity score estimation in self-selected samples

Self-selected samples are frequently obtained due to different levels of survey participation propensity of the survey individuals. When the survey participation is related to the survey topic of interest, propensity score weighting adjustment using auxiliary information may lead to biased estimation. In this paper, we consider a parametric model for the response probability that includes the study variable itself in the covariates of the model and proposes a novel application of two-phase sampling to estimate the parameters of the propensity model. The proposed method includes an experiment in which data are collected again from a subset of the original self-selected sample. With this two-phase sampling experiment, we can estimate the parameters in a propensity score model consistently. Then the propensity score adjustment can be applied to the self-selected sample to estimate the population parameters. Sensitivity of the selection model assumption is investigated from two limited simulation studies. The proposed method is applied to the 2012 Iowa Caucus Survey.
FUNCTIONS ON GROUPS AND COMPUTATIONAL COMPLEXITY

We give some connections between various functions defined on finitely presented groups (isoperimetric, isodiametric, Todd–Coxeter radius, filling length functions, etc.), and we study the relation between those functions and the computational complexity of the word problem (deterministic time, nondeterministic time, symmetric space). We show that the isoperimetric function can always be linearly decreased (unless it is the identity map). We present a new proof of the Double Exponential Inequality, based on context-free languages.
Empirical Solar Wind Forecasting from the Chromosphere

Recently, we correlated the inferred structure of the solar chromospheric plasma topography with solar wind velocity and composition data measured at 1 AU. We now offer a physical justification of these relationships and present initial results of an empirical prediction model based on them. While still limited by the fundamentally complex physics behind the origins of the solar wind and how its structure develops in the magnetic photosphere and expands into the heliosphere, our model provides a near-continuous range of solar wind speeds and composition quantities that are simply estimated from the inferred structure of the chromosphere. We suggest that the derived quantities may provide input to other, more sophisticated, prediction tools or models such as those that study coronal mass ejection (CME) propagation and solar energetic particle (SEP) generation.
A Nested Extreme Response Surface Approach for RBDO With Time-Dependent Probabilistic Constraints

A primary concern in practical engineering design is ensuring high system reliability throughout a product life-cycle subject to time-variant operating conditions and component deteriorations. Thus, the capability to deal with time-dependent probabilistic constraints in reliability-based design optimization is of vital importance in practical engineering design applications. This paper presents a nested extreme response surface (NERS) approach to efficiently carry out time-dependent reliability analysis and determine the optimal designs. The NERS employs kriging model to build a nested response surface of time corresponding to the extreme value of the limit state function. The efficient global optimization technique is integrated with the NERS to extract the extreme time responses of the limit state function for any given system design. An adaptive response prediction and model maturation mechanism is developed based on mean square error (MSE) to concurrently improve the accuracy and computational efficiency of the proposed approach. With the nested response surface of time, the time-dependent reliability analysis can be converted into the time-independent reliability analysis and existing advanced reliability analysis and design methods can be used. The NERS is integrated with RBDO for the design of engineered systems with time-dependent probabilistic constraints. Two case studies are used to demonstrate the efficacy of the proposed NERS approach.Copyright © 2012 by ASME
A conjunctive diquinane synthesis using a free-radical catalyzed intramolecular [3+2] methylenecyclopentane annulation

Abstract Alkylation of the methylenecyclopropane 1 with 4-alkynyl iodides followed by a free-radical mediated intramolecular methylenecyclopentane annulation composes a quick and efficient new diquinane synthesis.
Compositional variation of the phonon dispersion curves of bcc Fe-Ga alloys

Inelastic neutron scattering techniques have been used to measure the phonon dispersion curves of bcc ${\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Ga}}_{x}$ ($x=10.8$, 13.3, 16.0, 22.5) alloys as a function of Ga concentration. The phonon frequencies of every branch were found to decrease significantly with increasing Ga concentration. The softening was most pronounced for the ${T}_{2}[\ensuremath{\xi}\ensuremath{\xi}0]$ branch and, to a lesser extent, the $L[\ensuremath{\xi}\ensuremath{\xi}\ensuremath{\xi}]$ branch in the vicinity of $\ensuremath{\xi}=\frac{2}{3}$. The concentration dependence of the shear elastic constant ${C}^{\ensuremath{'}}=1∕2({C}_{11}\ensuremath{-}{C}_{12})$, calculated from the slope of the ${T}_{2}[\ensuremath{\xi}\ensuremath{\xi}0]$ branch, was found to agree with the results of sound velocity measurements. For the higher concentration sample measured, 22.5 at. % Ga, new branches appeared, an effect associated with the increase in the number of atoms per unit cell.
A pediatric airway atlas and its application in subglottic stenosis

Young children with upper airway problems are at risk for hypoxia, respiratory insufficiency and long term morbidity. Computational models and quantitative analysis would reveal airway growth patterns and benefit clinical care. To capture expected growth patterns we propose a method to build a pediatric airway atlas as a function of age. The atlas is based on a simplified airway model in combination with kernel regression. We show experimental results on children with subglottic stenosis to demonstrate that our method is able to track and measure the stenosis in pediatric airways.
Asymptotic limits and sum rules for gauge field propagators

Abstract For gauge field propagators, the asumptotic behavior is obtained in all directions of the complex k2-plane, and for general, linear, covariant gauges. Asymptotically free theories are considered. Except for coefficients, the functional form of the leading asymptotic terms is gauge-independent. Exponents are determined exactly by one-loop expressions. Sum rules are derived, which generalize the superconvergence relations obtained in the landau gauge.
Modeling of threaded joints using anisotropic elastic continua

Using fine material meshes in structural dynamics analysis is often impractical due to time step considerations. Unfortunately, fine meshes are typically required to capture the inherent physics in jointed connections. This is especially true in threaded connections which feature numerous contact interfaces and stress singularities. A systematic method is presented here for representing the threaded volume by a continuous, homogeneous, linear elastic, anisotropic equivalent material. The parameters of that equivalent material depend on thread geometry and the assumed contact condition between adjacent threads and are derived from detailed finite element simulations of a characteristic thread-pair unit cell. Numerical simulations using the equivalent material closely match the local stiffness through the load path calculated from the finely meshed thread models and also reproduce classical theoretical and experimental results from the literature.
Directing nuclear spin flips in InAs quantum dots using detuned optical pulse trains

We demonstrate that the sign of detuning of an optical pulse train from quantum dot resonances controls the direction of nuclear spin flips. This effect can produce a narrow, precise distribution of nuclear spin polarizations.
MASS AND HEAT TRANSFER IN A TURBULENT NON‐NEWTONIAN BOUNDARY LAYER

Abstract Using the three-zone model proposed by Levich, a new theoretical expression for turbulent heat and mass transport in inelastic non-Newtonian liquids has been proposed. This new model, j = 0.075 n 1 3 ( K /g9) −2 3 n v o (4− n ) 3 n ( C o − C b ) which has no adjustable parameters, has been derived under the assumption that the Schmidt number is fairly high as is the case in viscous polymer systems and fermentation broths. The predictive capability of this equation was tested in this work for flow situations for which the friction velocity vo is known: tubular non-Newtonian heat transfer and turbulent non-Newtonian mass transfer from a spinning disk. The excellent agreement between the available experimental data and the predictions of our model gives confidence to using the above model for that the heat and/or mass transfer rate increases if the pseudoplastic anomaly increases and that this enhancement is more pronounced in turbulent regime than it is under laminar conditions of flow.
C-THEOREM FOR DISORDERED SYSTEMS

Abstract We find an analog of Zamolodchikov's c -theorem for disordered two-dimensional non-interacting systems in their supersymmetric field theory representation. We show that the energy momentum tensor of such field theories must be a part of a supermultiplet, and that a new parameter b can be introduced with the help of that multiplet. b flows along the renormalization group trajectories much like the central charge for unitary two-dimensional field theories. While it has not been established if this flow is irreversible, that is, if b always flows down to lower values, it does so for all the cases worked out so far. b gives a new way to label different conformal field theories for disordered systems whose central charge is always 0. b turns out to be related to the central extension of a certain algebra, a generalization of the Virasoro algebra, which we show may be present at the critical points of these theories. b is also related to the finite size corrections of the physical free energy of disordered systems. We discuss possible applications by computing b for two-dimensional Dirac fermions with random gauge potential, in other words, for U(1∣1) Kac-Moody algebra.
New fluorescent nucleosides for real-time exploration of nucleic acids

Nucleic acids experience a variety of perturbations. These may include strand cleavage and ligation, local conformational changes, base flipping, as well as structural and environmental perturbations that are induced upon protein and low MW ligand binding. Since the native nucleobases are practically non-emissive, synthetic fluorescent nucleoside analogs that are sensitive to their local environment have become powerful tools for investigating nucleic acids structure, dynamics, recognition and damage. Our criteria for "ideal" fluorescent nucleoside analogs include: (a) high structural similarity to the native nucleobases to faithfully mimic their size and shape, as well as hybridization and recognition properties; (b) red shifted absorption (> 290 nm) to minimize overlap with the absorption of the natural bases; (c) red shifted emission (preferably in the visible range); (d) reasonable emission quantum efficiency; and, importantly, (e) sensitivity/responsiveness of one or all photophysical parameters (λem and/or ΦF, τ) to changes in the probe's microenvironment. The design and synthesis of new fluorescent isosteric nucleobase analogs and their utilization for the fabrication of "real-time" fluorescence-based discovery and detection assays are outlined.
Long-run wage and earnings losses of displaced workers

Displacement-related losses are estimated using National Longitudinal Survey of Youth data that span the years 1979–2000. The typical displaced worker faces losses of $34 065 during the period 4 years prior through 5 years following displacement. Proportionally, this represents a 10.8% loss compared to earnings of similar nondisplaced workers over the period. Considerable variation in losses is reported across worker types. Union, male and more mature workers suffer greater losses, respectively, than do their nonunion, female and younger counterparts. College graduates and high school dropouts are found to suffer lower losses compared to high school diploma holders and those who completed some college.
Photoinduced Electron Transfer in Folic Acid Investigated by Ultrafast Infrared Spectroscopy

Conformational control of excited-state intramolecular electron transfer (ET) in folic acid (FA) has been investigated using femtosecond time-resolved infrared (TRIR) spectroscopy. Ultrafast excite...
Modeling and analysis of the role of fast-response energy storage in the smart grid

The large short time-scale variability of renewable energy resources presents significant challenges to the reliable operation of power systems. This variability can be mitigated by deploying fast-ramping generators. However, these generators are costly to operate and produce environmentally harmful emissions. Fast-response energy storage devices, such as batteries and flywheels, provide an environmentally friendly alternative, but are expensive and have limited capacity. To study the environmental benefits of storage, we introduce a slotted-time dynamic residual dc power flow model with the prediction error of the difference between the generation (including renewables) and the load as input and the fast-ramping generation and the storage (charging/discharging) operation as the control variables used to ensure that the demand is satisfied (as much as possible) in each time slot. We assume the input prediction error sequence to be i.i.d. zero-mean random variables. The optimal power flow problem is then formulated as an infinite horizon average-cost dynamic program with the cost function taken as a weighted sum of the average fast-ramping generation and the loss of load probability. We find the optimal policies at the two extremes of the cost function weights and propose a two-threshold policy for the general case. We also obtain refined analytical results under the assumption of Laplace distributed prediction error and corroborate this assumption using simulated wind power generation data from NREL.
Neoliberal reforms and privatisation of reproductive health services in post-socialist Poland

The fall of state socialism in Poland in 1989 constituted a critical moment which redefined policies on reproductive health care and access to family planning, influenced by the renewed power of the Catholic church. Poland also embarked on neoliberal economic reforms that resulted in major cutbacks in social services and state health care coverage. The confluence of the elimination of contraceptive subsidies, privatisation of health care, and the intensification of bribes to underpaid health care providers created new challenges for women in accessing services. Furthermore, the 1993 ban on abortion resulted in a nearly total privatisation of this service, which is currently available clandestinely at a high price. Drawing on anthropological research in the Gdansk metropolitan region in 2007, this paper examines the restrictions on access to family planning, abortion, maternity care, assisted reproduction and other gynaecological services. It draws attention to the urgent need for state-subsidised family planning and other reproductive health services, the reform of abortion law, and regulation of privatised services. Higher wages for public sector health professionals and better public health provision would curb informal payments. The state should support the legitimacy of women's health needs and reproductive and sexual autonomy.
Magic's Circuit Extractor

This fast hierarchical circuit extractor for the Magic VLSI layout system derives its speed from its ability to handle hiearchical arrays, and from a new algorithm based on corner-stitching, a geometrical data structure for representing Manhattan shapes. Corner-stitching's ability to find adjacent mask information is critical to the basic extractor speed, and its ability to search areas makes the hiearchical extraction algorithm practical. The extractor is incremental, necessitating re-extraction of only a few cells after a layout is modified. It accepts a hierarchical layout that may contain nearly arbitrary overlaps between cells, and produces a circuit description with the same hierarchical structure as the layout. The extractor can completely extract a 37,000-transistor chip in 20 minutes of VAX CPU time, or incremetally in an average of 8 minutes. The extractor processes 50-65 FETS per second on a VAX-11/780 running Unix. if only substrate capacitance is being extracted. If coupling capacitance is also extracted, the basic extractor processes 25-35 transistors per second.
Selective oxidations with ceric methanesulfonate and ceric trifluoromethanesulfonate

Abstract Cerium(IV) in aqueous methanesulfonic acid and trifluoromethanesulfonic acid are excellent reagents for the oxidation of alkyl and polycyclic aromatics to aromatic aldehydes, ketones and quinones.
Mycophenolate Mofetil for Autoimmune Hepatitis: A Single Practice Experience

Autoimmune hepatitis (AIH) is refractory to standard therapy with prednisone and azathioprine in 20% of patients. Investigators are exploring alternative immunosuppressant treatments, including mycophenolate mofetil (MMF). We assessed the outcome of MMF therapy in patients with AIH and related disorders. A retrospective analysis was performed in 16 patients with AIH, immune cholangitis, and overlap syndromes between AIH, primary biliary cirrhosis, and primary sclerosing cholangitis. MMF was used in lieu of azathioprine on account of patients’ intolerance to azathioprine, disease that was refractory to prednisone plus azathioprine, or the perceived potency of MMF. With initiation of MMF, median ALT decreased from 81.5 U/l to 42.5 U/l (P = 0.03). Median prednisone dose decreased from 10 mg to 2.5 mg (P = 0.01). Prednisone was completely withdrawn in three patients. Five of 16 patients (31%) achieved biochemical remission, defined as a reduction in ALT from greater than to less than twice normal. Seven additional patients (44%) were maintained in biochemical remission. Two patients had an incomplete response to MMF and two patients experienced treatment failure. MMF was tolerated well in all but one patient, who discontinued the drug on account of paresthesias. MMF may be a safe and effective alternative to azathioprine in patients with AIH and related disorders.
Superluminal Vector in Ghost-free Massive Gravity

We present a classical analysis on the issue of vector superluminality in the decoupling limit ghost-free massive gravity with a Minkowski reference metric. We show explicitly in the Lorenz gauge that the theory is free of superluminal vector excitations around a nontrivial solution at the cubic order in the fields. In the same gauge, we demonstrate that superluminal vector modes arise at the quartic order and compute some superluminal propagating solutions. We then generalize our findings to all orders in a gauge-independent way. We check the physical consistency of the vector superluminalities, arguing that they are not physically detectable in the perturbation theory but could be trusted classically in the strong coupling region. Nevertheless, these superluminalities involve only low frequency group and phase velocities and are unable to determine the acausality of the theory.
Limits on SUSY particle spectra from proton stability and dark matter constraints

Abstract It is shown that the combined constraints on the amount of cold dark matter and of proton stability produce a stringent upper limit on the gluino mass m g (and hence on the lightest neutralino mass m χ 1 0 ≃m g /7 for a large class of gravity mediated supergravity unified models. One finds that for the minimal SU(5) model current data (Kamiokande) restricts m g ≤400 GeV for a scalar soft breaking mass m0≤1 TeV. Expected future data from Super Kamiokande and ICARUS will be sensitive to the entire range of gluino mass for m0≤1 TeV, and be sensitive to the region m g ≥500 GeV for m0≤5 TeV. Effects of quark mass textures are studied and one finds that the bound m g ≤500 GeV holds when the experimental proton lifetime for the p→ ν K + mode becomes ≥5×1032 yr. Implications of these results for a test of these models at the Tevatron and at the LHC are discussed. The effects of non-universal soft breaking in the Higgs and the third generation squark sectors are also examined, and it is found that the proton lifetime is sensitive to these non-universal effects. The current data already eliminates some regions of non-universalities. The constraints of proton stability on the direct detection of dark matter are seen to reduce the maximum event rates by as much as a factor of 103.
Interpersonal, Intertemporal and Spatial Variation in Risk Perceptions: Evidence from East Africa

Summary This study investigates variation over time, space and household and individual characteristics in how people perceive different risks. Using original data from the arid and semi-arid lands of East Africa, we explore how individuals assess their relative level of concern about risks. The primary determinants of risk rankings are found to be changing community level variables over time, with household specific and individual specific variables exhibiting much less influence. Individuals throughout this area are most concerned about food security and human health, so that development efforts that directly address these problems should be given the highest priority.
Infrared and raman spectra of metal 1,2,4,5-benzenetetracarboxylates: Evidence for very short, strong hydrogen bonds

Abstract Salts of 1,2,4,5-benzenetetracarboxylic acid with copper, aluminum, ammonium, cobalt(II), thallium(I), tin(II), uranyl ion, zinc, manganese, iron(II), nickel, potassium and sodium have been prepared and characterized by their IR spectra. The salts of aluminum, ammonium, thallium(I), tin(II), zinc, iron(II), nickel, potassium and sodium had not been reported before with adequate characterization. Raman spectra of selected compounds also aided structural interpretation. The IR spectra of Na 2 C 10 H 4 O 8 ·2H 2 O, Fe(C 10 H 5 O 8 ) 2 ·12H 2 O, Zn(C 10 H 5 O 8 ) 2 ·12H 2 O, Ni(C 10 H 5 O 8 ) 2 ·12H 2 O, (NH 4 ) 3 C 10 H 3 O 8 ·H 2 O and CoC 10 H 4 O 8 ·6H 2 O indicate very short, strong hydrogen bonds in these compounds. The IR and Raman spectra can be used to determine the mode of coordination (if any) of the carboxylate groups of 1,2,4,5- benzenetetracarboxylate to metal ions.
Structure and bonding in the omnicapped truncated tetrahedral Au20 cluster: analogies between gold and carbon cluster chemistry.

The proposed omnicapped truncated tetrahedral structure of the recently reported Au20 cluster can be generated from a regular dodecahedron by forming two transannular Au−Au bonds across each face while preserving T symmetry. An electron-precise chemical bonding scheme accounts for the large band gap (1.77 eV) of Au20 and relates its structure to that of titanacarbohedrene Ti8C12 and Os20(CO)402-.