cssi/SciSciGPT-SciSciNet huggingface dataset:
Non-cooperative spectrum access: the dedicated vs. free spectrum choice

We consider a dynamic spectrum access system in which Secondary Users (SUs) choose to either acquire dedicated spectrum or to use spectrum-holes (white spaces) which belong to Primary Users (PUs). The tradeoff incorporated in this decision is between immediate yet costly transmission and free but delayed transmission (a consequence of both the possible appearance of PUs and sharing the spectrum holes with multiple SUs). We first consider a system with a single PU band, in which the SU decisions are fixed. Employing queueing-theoretic methods, we obtain explicit expressions for the expected delays associated with using the PU band. Based on that, we then consider self-interested SUs and study the interaction between them as a noncooperative game. We prove the existence and uniqueness of a symmetric Nash equilibrium, and characterize the equilibrium behavior explicitly. Using our equilibrium results, we show how to maximize revenue from renting dedicated bands to SUs. Finally, we extend the scope to a scenario with multiple PUs, show that the band-pricing analysis can be applied to some special cases, and provide numerical examples.
Determination of pyrrolizidine alkaloids in commercial comfrey products (Symphytum sp.)

The presence of hepatotoxic pyrrolizidine alkaloids in comfrey (Symphytum sp.) and the widespread use of decoctions of this plant as a beverage (herbal tea) are of increasing concern. A method for the extraction and solid-phase concentration and capillary gas chromatographic determination of these alkaloids and their N-oxides in botanical materials has been developed and was applied to eleven comfrey-containing products purchased from retail health-food outlets in the Washington, DC, area during May-June 1989. Nine of the 11 products were found to contain measurable quantities of one or more of the alkaloids, in ranges from 0.1 to 400.0 ppm. Products containing comfrey leaf in combination with one or more other ingredients were found to contain the lowest alkaloid levels. Highest levels were found in bulk comfrey root, followed by bulk comfrey leaf. The species of the bulk material was verified by thin-layer chromatography and other means.
Chiral squaramide derivatives are excellent hydrogen bond donor catalysts.

Thioureas represent the dominant platform for hydrogen bond promoted asymmetric catalysts. A large number of reactions, reported in scores of publications, have been successfully promoted by chiral thioureas. The present paper reports the use of squaramides as a highly effective new scaffold for the development of chiral hydrogen bond donor catalysts. Squaramide catalysts are very simple to prepare. The (−)-cinchonine modified squaramide (5), easily prepared through a two-step process from methyl squarate, was shown to be an effective catalyst, even at catalyst loadings as low as 0.1 mol%, for the conjugate addition reactions of 1,3-dicarbonyl compounds to β-nitrostyrenes. The addition products were obtained in high yields and excellent enantioselectivities.
Double affine Hecke algebras and difference Fourier transforms

In the paper, we introduce and calculate difference Fourier transforms on representations of the double affine Hecke algebras in polynomilas, polynomials multiplied by the Gaussian, and various spaces of delta-functions including finite-dimensional ones, give a general description of the semisimple representations with a special consideration of the GL-case, and then gradually restrict ourselves with spherical, pseudo-unitary, and Fourier-invariant representations. The latter generalize the Verlinde algebras and lead to new Gauss-Selberg sums and Macdonald's eta-type identities.
Dyonic instantons in five-dimensional gauge theories

Abstract We show that there exist finite energy, non-singular instanton solutions for five-dimensional theories with broken gauge symmetry. The soliton is supported against collapse by a non-zero electric charge. The low-energy dynamics of these solutions is described by motion on the ADHM moduli space with potential.
Eigenvalue problem and a new product in cohomology of flag varieties

Let G be a connected semisimple complex algebraic group and let P be a parabolic subgroup. In this paper we define a new (commutative and associative) product on the cohomology of the homogenous spaces G/P and use this to give a more efficient solution of the eigenvalue problem and also for the problem of determining the existence of G-invariants in the tensor product of irreducible representations of G. On the other hand, we show that this new product is intimately connected with the Lie algebra cohomology of the nil-radical of P via some works of Kostant and Kumar. We also initiate a uniform study of the geometric Horn problem for an arbitrary group $G$ by obtaining two (a priori) different sets of necessary recursive conditions to determine when a cohomology product of Schubert classes in G/P is non-zero. Hitherto, this was studied largely only for the group \SL(n).
Bayes Factor Consistency for One-way Random Effects Model

In this article, we consider Bayesian hypothesis testing for the balanced one-way random effects model. A special choice of the prior formulation for the ratio of variance components is shown to yield an explicit closed-form Bayes factor without integral representation. Furthermore, we study the consistency issue of the resulting Bayes factor under three asymptotic scenarios: either the number of units goes to infinity, the number of observations per unit goes to infinity, or both go to infinity. Finally, the behavior of the proposed approach is illustrated by simulation studies.
Hinged Dissections Exist

We prove that any finite collection of polygons of equal area has a common hinged dissection. That is, for any such collection of polygons there exists a chain of polygons hinged at vertices that can be folded in the plane continuously without self-intersection to form any polygon in the collection. This result settles the open problem about the existence of hinged dissections between pairs of polygons that goes back implicitly to 1864 and has been studied extensively in the past ten years. Our result generalizes and indeed builds upon the result from 1814 that polygons have common dissections (without hinges). Our proofs are constructive, giving explicit algorithms in all cases. For two planar polygons whose vertices lie on a rational grid, both the number of pieces and the running time required by our construction are pseudopolynomial. This bound is the best possible, even for unhinged dissections. Hinged dissections have possible applications to reconfigurable robotics, programmable matter, and nanomanufacturing.
Cosmos++: Relativistic Magnetohydrodynamics on Unstructured Grids with Local Adaptive Refinement

A new code and methodology are introduced for solving the fully general relativistic magnetohydrodynamic (GRMHD) equations using time-explicit, finite-volume discretization. The code has options for solving the GRMHD equations using traditional artificial-viscosity (AV) or non-oscillatory central difference (NOCD) methods, or a new extended AV (eAV) scheme using artificial-viscosity together with a dual energy-flux-conserving formulation. The dual energy approach allows for accurate modeling of highly relativistic flows at boost factors well beyond what has been achieved to date by standard artificial viscosity methods. it provides the benefit of Godunov methods in capturing high Lorentz boosted flows but without complicated Riemann solvers, and the advantages of traditional artificial viscosity methods in their speed and flexibility. Additionally, the GRMHD equations are solved on an unstructured grid that supports local adaptive mesh refinement using a fully threated oct-tree (in three dimensions) network to traverse the grid hierarchy across levels and immediate neighbors. A number of tests are presented to demonstrate robustness of the numerical algorithms and adaptive mesh framework over a wide spectrum of problems, boosts, and astrophysical applications, including relativistic shock tubes, shock collisions, magnetosonic shocks, Alfven wave propagation, blast waves, magnetized Bondi flow, and the magneto-rotational instability in Kerr black hole spacetimes.
N* mass spectrum from an anisotropic action

Abstract Results are reported for N* masses in the 1 2 + and 1 2 − sectors on an anisotropic lattice. The gauge action is the usual plaquette plus rectangle type, the quark action is of the D234 type, both having tadpole-improved tree-level coefficients. Clear splittings from the nucleon ground state are observed with smeared operators and 500 configurations. The first excited states in each channel are further isolated, using a correlation matrix and the variational method. The basic pattern of these splittings is consistent with experimental observations.
Synthesis and characterization of Hf2PbC, Zr2PbC and M2SnC (M=Ti, Hf, Nb or Zr)

Abstract Predominantly single phase (92–94 vol.%), fully dense samples of Hf2SnC, Zr2SnC, Nb2SnC, Ti2SnC, Hf2PbC and Zr2PbC were fabricated by reactively HIPing the stoichiometric mixture of the corresponding elemental powders in the 1200–1325°C temperature range for 4–48 h. The latter two, fabricated here for the first time, required a further anneal of 48–96 h to increase the volume fraction of ternary phases. Hf2PbC and Zr2PbC are unstable in ambient atmospheres at room temperature. As a family these compounds are good electrical conductors; the lowest and highest values of the electrical conductivities were, respectively, 2.2×106 (Ω.m)−1 for Hf2SnC and 13.4×106 (Ω.m)−1 for Hf2PbC. The Vickers hardness values range from 3 to 4 GPa. All compounds are readily machinable. The Young's moduli of Zr2SnC, Nb2SnC and Hf2SnC are, respectively, 178, 216 and 237 GPa. The thermal coefficients of expansion, TCE's, of the ternaries scale with those of the corresponding binaries, and are relatively low for such readily machinable solids. The lowest TCE belonged to Nb2SnC [(7.8±0.2)×10−6 K−1], and the highest to Ti2SnC [(10±0.2)×10−6 K−1]. The TCE's of Hf and Zr containing ternaries cluster around (8.2±0.2)×10−6 K−1. All the synthesized ternary carbides were found to dissociate into the transition metal carbide and the A-group element in the 1250–1390 °C temperature range.
Excited Young diagrams, equivariant K -theory, and Schubert varieties

We give combinatorial descriptions of the restrictions to T-fixed points of the classes of structure sheaves of Schubert varieties in the T-equivariant K-theory of Grassmannians and of maximal isotropic Grassmannians of orthogonal and symplectic types. We also give formulas, based on these descriptions, for the Hilbert series and Hilbert polynomials at T-fixed points of the corresponding Schubert varieties. These descriptions and formulas are given in terms of two equivalent combinatorial models: excited Young diagrams and set-valued tableaux. The restriction fomulas are positive, in that for a Schubert variety of codimension d, the formula equals (-1)^d times a sum, with nonnegative coefficients, of monomials in the expressions (e^{-\alpha}-1), as \alpha runs over the positive roots. In types A_n and C_n the restriction formulas had been proved earlier by [Kreiman 05], [Kreiman 06] by a different method. In type A_n, the formula for the Hilbert series had been proved earlier by [Li-Yong 12]. The method of this paper, which relies on a restriction formula of [Graham 02] and [Willems 06], is based on the method used by [Ikeda-Naruse 09] to obtain the analogous formulas in equivariant cohomology. The formulas we give differ from the K-theoretic restriction formulas given by [Ikeda-Naruse 11], which use different versions of excited Young diagrams and set-valued tableaux. We also give Hilbert series and Hilbert polynomial formulas which are valid for Schubert varieties in any cominuscule flag variety, in terms of the 0-Hecke algebra.
Ion sizes and finite-size corrections for ionic-solvation free energies

Free energies of ionic solvation calculated from computer simulations exhibit a strong system size dependence. We perform a finite-size analysis based on a dielectric-continuum model with periodic boundary conditions. That analysis results in an estimate of the Born ion size. Remarkably, the finite-size correction applies to systems with only eight water molecules hydrating a sodium ion and results in an estimate of the Born radius of sodium that agrees with the experimental value.
AN ALGORITHM TO CLASSIFY RATIONAL 3-TANGLES

A 3-tangle T is the disjoint union of three properly embedded arcs in the unit 3-ball; it is called rational if there is a homeomorphism of pairs from (B3, T) to (D2 × I, {x1, x2, x3} × I). Two rational 3-tangles T and T′ are isotopic if there is an orientation-preserving self-homeomorphism h : (B3, T) → (B3, T′) that is the identity map on the boundary. In this paper, we give an algorithm to check whether or not two rational 3-tangles are isotopic by using a modified version of Dehn's method for classifying simple closed curves on surfaces.
X-Ray Emission from the Double Neutron Star Binary B1534+12: Powered by the Pulsar Wind?

We report the detection of the double neutron star binary (DNSB) B1534+12 (=J1537+1155) with the Chandra X-Ray Observatory. This DNSB (Porb = 10.1 hr) consists of the millisecond (recycled) pulsar J1537+1155A (PA = 37.9 ms) and a neutron star not detected in the radio. After the remarkable double pulsar binary J0737-3039, it is the only other DNSB detected in X-rays. We measured the flux of (2.2 ± 0.6) × 10-15 ergs s-1 cm-2 in the 0.3-6 keV band. The small number of collected counts allows only crude estimates of spectral parameters. The power-law fit yields the photon index Γ = 3.2 ± 0.5 and the unabsorbed 0.2-10 keV luminosity LX ≈ 6 × 1029 ergs s-1 ≈ 3 × 10-4ĖA, where ĖA is the spin-down power of J1537+1155A. Alternatively, the spectrum can be fitted by a blackbody model with T ≈ 2.2 MK and the projected emitting area of ~5 × 103 m2. The distribution of photon arrival times over binary orbital phase shows a deficit of X-ray emission around apastron, which suggests that the emission is caused by interaction of the relativistic wind from J1537+1155A with its neutron star companion. We also reanalyzed the Chandra and XMM-Newton observations of J0737-3039 and found that its X-ray spectrum is similar to the spectrum of B1534+12, and its X-ray luminosity is about the same fraction of ĖA, which suggests similar X-ray emission mechanisms. However, the X-ray emission from J0737-3039 does not show orbital phase dependence. This difference can be explained by the smaller eccentricity of J0737-3039 or a smaller misalignment between the equatorial plane of the millisecond pulsar and the orbital plane of the binary.
Shape Memory Alloy Deployment of Membrane Mirrors for Spaceborne Telescopes

Abstract : The objectives of this research were to develop and refine a shape memory alloy (SMA) modeling approach, the martensite twin reorientation (MTR) subroutine to predict the transient response of a spaceborne membrane optic SMA deployment actuator spine system. In concert with a commercial finite element solver this application supports multi- dimensional temperature-displacement transient predictions of the shape memory effect (SME) exhibited by SMAs through implementation of a phenomenological constitutive law. The scope of this study was to model the relation of input power magnitude and waveform to stress fields reaction forces and thermal fields for the figure acquisition of a gossamer reflector. Of particular interest is the stress and thermal field history of the polymeric membrane concentrator through the deployment to prevent mechanical and thermal failure as limited experimental or modeling analysis results exists for SMA deployment schemes. Thermal authority over the concentrator was found locally limited to the spine interface. Upon aperture engagement, the integrated model's first excursion cycle frequency excited by all three loading regimes was non-unique, regardless of the preceding temporal character of the spine's response. This tendency suggests a coupling between the structural dynamic designs for deployment and in-service, deployed architectures. Aspects of the deployment sequence warranting further study and issues for tackle to further develop the MTR subroutine are identified. Technology addressed through this thesis research is intended to foster and mature successive large, launch-packaged space vehicle programs.
Toward a typology of health 2.0 collaboration platforms and websites

During the past decade, the proliferation of social media has infiltrated various sectors of social and business communications. Of particular interest is the growth of health related websites and the healthcare sector’s adoption of social media. In this paper, we develop a typology of Health 2.0 collaboration platforms and websites. Two major types of actors within Health 2.0 websites are health professionals (P) and health consumers (C). Each actor can serve as either support provider or support recipient. We focus on the six major Health 2.0 collaboration platforms including health blogs, physician-ratings, medicine-ratings, online health social networks, health discussion boards, and ask-a-doctor. We categorize these platforms into four major types including professional-to-professional (P2P), professional-to-consumer (P2C), consumer-to-consumer (C2C), and consumer-to-professional (C2P). Then, based on the combination of collaboration platforms provided by Health 2.0 websites, we categorize these websites into P2P, P2C, C2C, and C2P types. We describe each type and utilize the typology to investigate 20 Health 2.0 websites and the collaboration platforms they provide. Our typology can be used as groundwork for future research on health social media.
Elevated concentrations of primordial radionuclides in sediments from the Reedy River and surrounding creeks in Simpsonville, South Carolina.

Abstract A gamma-ray survey and analysis of 16 riverbed samples from the Reedy River watershed near Simpsonville, SC were conducted and compared with national and international studies of primordial radionuclides. The study reported here follows on a recent discovery of anomalously high uranium concentrations in several private well waters in the area. An HPGe spectrometer was used for quantification of gamma emitting radionuclides in the sediments. All sediments contained radionuclides from the uranium and thorium series as well as 40 K. Uranium-238 concentrations in sediment samples ranged from 11.1 to 74.2 Bq kg −1 . The measured radionuclide concentrations were compared with data from UNSCEAR and NURE reports. The river and stream sediment data were augmented by in situ NaI(Tl) gamma-ray spectrometer measurements. Comparisons between the ex situ and in situ measurements indicate equivalently distributed uranium in the surface soils and stream sediments, the source of which is likely attributed to the monazite belts that are known to exist in the area.
Could large CP-violation be detected at colliders?

Abstract We argue that CP -violation effects below a few × 10 −3 are probably undetectable at hadron and electron colliders. Thus only operators whose contributions interfere with tree-level Standard Model amplitudes are detectable. We list these operators for Standard Model external particles and some two- and three-body final state reactions that could show detectable effects. These could test electroweak baryogenesis scenarios.
Experimental Evidence that the Onset of Mechanical Softening in Nanocrystalline Metals is Strain Rate Dependent

This paper reports on the influence of strain rate on the onset of mechanical softening of nanocrystalline gold at room temperature. Micro-tensile testing was performed with applied strain rates on the order of 10−4 s−1 to 10−6 s−1. Our results defined a threshold strain rate, whereby plastic deformation at larger rates was dominated by dislocation processes and at smaller rates by one or more other deformation mechanisms.
Synthesis of novel oxime functionalized aldol products via michael addition of oximes onto baylis-hillman adducts

Abstract Triphenylphosphine‐catalyzed Michael addition of oximes 2 onto Baylis–Hillman (B‐H) adducts 1 led to an easy access to a novel class of oxime functionalized aldol products 3. This demonstrates the first use of an oxygen‐centered nucleophile in Michael addition to B‐H adducts, without touching any other functional group. Deprotection of oxime in 3 was further demonstrated using molecular hydrogen (1 atm) and 10% Pd/C (cat.) to furnish functionalized 1,3‐diols 4 as potentially useful synthons with optional backbone choice (R3 and EWG). DRL Publication No. 354. Part of these results was presented at Pharmacophore 2004, January 16–17, 2004, an international symposium organized by Dr. Reddy's Laboratories Ltd. on the occasion of its achievement in drug discovery.
The Britannia Field Development

The Britannia field was developed ahead of schedule at a cost 20% lower than the approved budget. This paper provides an overview of the development project and, by use of a performance-improvement model, explains how these outstanding results were achieved. This outcome would not have been possible with traditional project-management philosophies. The processes and techniques described are applicable to other capital investment projects.
Synthesis of 2-Aryl-1-(Phenylsulfonyl)Pyrroles

Abstract The synthesis of 1-(phenylsulfonyl)pyrrole-2-boronic acid has been accomplished by a process involving the directed lithiation of 1-(phenylsulfonyl)-pyrrole. The former has been shown to couple smoothly with aryl bromides and iodides under Suzuki conditions to afford 2-aryl-1-(phenylsulfonyl)pyrroles.
Spitzer IRAC Detection and Analysis of Shocked Molecular Hydrogen Emission

We use statistical equilibrium equations to investigate the Infrared Array Camera (IRAC) color space of shocked molecular hydrogen. The location of shocked H2 in [3.6] – [4.5] versus [4.5] – [5.8] color is determined by the gas temperature and density of neutral atomic hydrogen. We find that high excitation H2 emission falls in a unique location in the color-color diagram and can unambiguously be distinguished from stellar sources. In addition to searching for outflows, we show that the IRAC data can be used to map the thermal structure of the shocked gas. We analyze archival Spitzer data of Herbig-Haro object HH 54 and create a temperature map, which is consistent with spectroscopically determined temperatures.
Approaches to the Automatic Generation and Control of Finite Element Meshes

The algorithmic approaches being taken to the development of finite element mesh generators capable of automatically discretizing general domains without the need for user intervention are discussed. It is demonstrated that because of the modeling demands placed on a automatic mesh generator, all the approaches taken to date produce unstructured meshes. Consideration is also given to both a priori and a posteriori mesh control devices for automatic mesh generators as well as their integration with geometric modeling and adaptive analysis procedures.
Extended Lifetime in Computational Evolution of Isolated Black Holes

Solving the 4-d Einstein equations as evolution in time requires solving equations of two types: the four elliptic initial data (constraint) equations, followed by the six second-order evolution equations. Analytically the constraint equations remain solved under the action of the evolution, and one approach is to simply monitor them (unconstrained evolution). The problem of the 3-d computational simulation of even a single isolated vacuum black hole has proven to be remarkably difficult. Recently, we have become aware of two publications that describe very long term evolution, at least for single isolated black holes. An essential feature in each of these results is constraint subtraction. Additionally, each of these approaches is based on what we call “modern,” hyperbolic formulations of the Einstein equations. It is generally assumed, based on computational experience, that the use of such modern formulations is essential for long-term black hole stability. We report here on comparable lifetime results based on the much simpler (“traditional”) $${\dot g} - {\dot K}$$ formulation. With specific subtraction of constraints, with a simple analytic gauge, with very simple boundary conditions, and for moderately large domains with moderately fine resolution, we find computational evolutions of isolated non-spinning black holes for times exceeding 1000 GM/c2. We have also carried out a series of constrained 3-d evolutions of single isolated black holes. We find that constraint solution can produce substantially stabilized long-term single hole evolutions. However, we have found that for large domains, neither constraint-subtracted nor constrained $${\dot g} - {\dot K}$$ evolutions carried out in Cartesian coordinates admit arbitrarily long-lived simulations. The failure appears to arise from features at the inner excision boundary; the behavior does generally improve with resolution.
Sparse regression codes for multi-terminal source and channel coding

We study a new class of codes for Gaussian multiterminal source and channel coding. These codes are designed using the statistical framework of high-dimensional linear regression and are called Sparse Superposition or Sparse Regression codes. Codewords are linear combinations of subsets of columns of a design matrix. These codes were introduced by Barron and Joseph and shown to achieve the channel capacity of AWGN channels with computationally feasible decoding. They have also recently been shown to achieve the optimal rate-distortion function for Gaussian sources. In this paper, we demonstrate how to implement random binning and superposition coding using sparse regression codes. In particular, with minimum-distance encoding/decoding it is shown that sparse regression codes attain the optimal information-theoretic limits for a variety of multiterminal source and channel coding problems.
Exact estimation for Markov chain equilibrium expectations

We introduce a new class of Monte Carlo methods, which we call exact estimation algorithms. Such algorithms provide unbiased estimators for equilibrium expectations associated with real-valued functionals defined on a Markov chain. We provide easily implemented algorithms for the class of positive Harris recurrent Markov chains, and for chains that are contracting on average. We further argue that exact estimation in the Markov chain setting provides a significant theoretical relaxation relative to exact simulation methods.
The Laplacian on planar graphs and graphs on surfaces

These are lecture notes for the Current Developments in Mathematics conference at Harvard, November, 2011. We discuss topological, probabilistic and combinatorial aspects of the Laplacian on a graph embedded on a surface. The three main goals are to discuss: (1) for "circular" planar networks, the characterization due to Colin de Verdi\`ere of Dirichlet-to-Neumann operator; (2) The connections with the random spanning tree model; and (3) the characteristic polynomial of the Laplacian on an annulus and torus.
Parameter and State Model Reduction for Large-Scale Statistical Inverse Problems

A greedy algorithm for the construction of a reduced model with reduction in both parameter and state is developed for an efficient solution of statistical inverse problems governed by partial differential equations with distributed parameters. Large-scale models are too costly to evaluate repeatedly, as is required in the statistical setting. Furthermore, these models often have high-dimensional parametric input spaces, which compounds the difficulty of effectively exploring the uncertainty space. We simultaneously address both challenges by constructing a projection-based reduced model that accepts low-dimensional parameter inputs and whose model evaluations are inexpensive. The associated parameter and state bases are obtained through a greedy procedure that targets the governing equations, model outputs, and prior information. The methodology and results are presented for groundwater inverse problems in one and two dimensions.
Controlled Sensing for Sequential Multihypothesis Testing with Controlled Markovian Observations and Non-Uniform Control Cost

Abstract A new model for controlled sensing for multihypothesis testing is proposed and studied in the sequential setting. This new model, termed a controlled Markovian observation model, exhibits a more complicated memory structure in the controlled observations than existing models. In addition, instead of penalizing just the delay until the final decision time as in standard sequential hypothesis testing problems, a much more general cost structure is considered that entails accumulating the total control cost with respect to an arbitrary control cost function. An asymptotically optimal test is proposed for this new model and is shown to satisfy an optimality condition formulated in terms of decision-making risk. It is shown that the optimal causal control policy for the controlled sensing problem is self-tuning, in the sense of maximizing an inherent “inferential” reward simultaneously under every hypothesis, with the maximal value being the best possible corresponding to the case where the true hypot...
Cyclic and finite surgeries on pretzel knots

We classify Dehn surgeries on (p,q,r) pretzel knots resulting in a manifold M(α) having cyclic fundamental group and analyze those leading to a finite fundamental group. The proof uses the theory of cyclic and finite surgeries developed by Culler, Shalen, Boyer, and Zhang. In particular, Culler-Shalen seminorms play a central role.
The two year and four year computer technology programs at Purdue University

There are eight kinds of educational programs in the United States which presently supply industry with the majority of its computer-EDP oriented employees. For lack of better terminology, I would classify these programs as follows:(1) The two year Data Processing (DP) programs which are concentrated at vocational institutions, community colleges, junior colleges and at some senior colleges and universities.(2) The four year academic programs offered by many senior colleges and universities in the areas of Business Data Processing and Computer Science.(3) The graduate level programs in Information Systems and Computer Science offered at some major colleges and universities.(4) The specialized programs offered by the various computer manufacturers' education centers.(5) The company in-house training programs.(6) The so-called private commercial schools, many of which have been established through franchising, and which usually offer training ranging from 3 to 12 months.(7) The private home study schools.(8) The various high schools which offer vocational oriented training programs in EDP.
Fiscal Policy with Heterogeneous Agents and Incomplete Markets

I undertake a quantitative investigation into the short run effects of changes in the timing of proportional income taxes for model economies in which heterogeneous households face a borrowing constraint. Temporary tax changes are found to have large real effects. In the benchmark model, a temporary tax cut increases aggregate consumption on impact by around 29 cents for every dollar of tax revenue lost. Comparing the benchmark incomplete-markets model to a complete-markets economy, income tax cuts provide a larger boost to consumption and a smaller investment stimulus when asset markets are incomplete. Copyright 2005, Wiley-Blackwell.
Short-term prediction of local wind conditions

This paper will describe a system which predicts the expected power output of a number of wind farms. The system is automatic and operates on-line. The paper will quantify the accuracy of the predictions and will also give examples of the performance for specific storm events. An actual implementation of the system will be described and the robustness demonstrated.
Addition of electrochemically-generated anions to aldehydes and olefins: effect of reaction medium and anion basicity

Abstract The electrochemically-induced addition of nitroalkenes to mono and dialdehydes as well as mono and diolefins was investigated. The reactivity was highly dependent on the solvent. Selectivity of addition has been made possible by controlling the charge injected upon electrolysis of a pure nitromethane solution in the presence of 1,3- or 1,4-benzenedicarboxaldehyde to direct the reaction toward the mono- or bis-(nitroalcohol). Dehydration of the latter resulted in almost quantitative yields of 1,4-bis(2-nitroethenyl)benzene. This diolefin was further submitted to attack of various electrochemically generated nucleophiles. Whether polymerization, double Michael addition or no reaction occurred, depended greatly on the p K a and on the structure of the starting anion.
Completing the Square to Find the Supersymmetric Matter Effective Action Induced by Coupling to Linearized N=1 Supergravity☆

Abstract We consider generic N=1 supersymmetric matter coupled to linearized N=1 supergravity through the multiplet of currents. By completing the square, we find the effective action giving the leading supergravity induced correction to the matter dynamics, expressed explicitly as a quadratic form in the components of the current multiplet. The effective action is supersymmetry invariant through an interplay of the local terms arising from the auxiliary field couplings, and the nonlocal terms arising from graviton and gravitino exchange, neither of which is separately invariant. Having an explicit form for the supergravity induced effective action is a first step in studying effects of supergravity corrections on dynamical supersymmetry breaking and condensate formation in supersymmetric matter dynamics. In the Appendixes we give explicit expressions for the currents, in our notational conventions, in the Wess–Zumino and supersymmetric Yang–Mills models.
Evaluating the Impact of Performance Uncertainty on Vehicle Demand and Design

preliminary vehicle design. From a customer perspective, desirability can be mapped to the performance specifications of a design. Desirability drives the customer-perceived value of the vehicle, which when combined with price, serves to drive the vehicle’s market share. Such vehicle designs must also be technically feasible from an engineering perspective, ensuring and establishing confidence that they can be realized and manufactured. Traditional analyses of desirability, however, are conducted by presenting discrete performance specifications. Incorporating uncertainty into a preliminary design’s performance allows the consumer to be presented with performance specifications characterized by either a mean value or distribution, permitting investigation of variation from a customer’s perspective. The goal of this research is to take a set of non-dominated solutions and combine them with a random utility model, to explore how the variance in both models impacts the final solution. This paper explores the impact of uncertainty in vehicle design, with potential vehicles first being created and assessed for feasibility. A Technical Feasibility Model is utilized to narrow down the possible designs to those that are both feasible and Pareto optimal. Capturing customer preference ranges for each objective is made possible with the implementation of utility functions whose coefficients are dictated by a referenced market model. In addition to defining the customer preference ranges for this problem, uncertainty is applied to each performance objective considered within the vehicle model. The vehicle designs are then evaluated, combining the variances associates with uncertainty in vehicle performance and the aspects of a random utility model.
A substructure technique for dynamics of flexible mechanical systems with contact-impact

A substructure synthesis method is proposed to account for contact-impact effects in flexible components of mechanical systems. Components that may come into contact is divided into substructures, on each of which local deformation modes are defined to described deformation fields of components. Constraint modes and fixed interface normal modes are used to account for elastic deformation within each substructure. A constraint addition-deletion technique is used to account for contact between impacting bodies. Lagrange multipliers associated with the constraints, which represent constraint forces, are used to determine separation of contacting nodes. Use of the method is illustrated on problems of longitudinal and transverse impact of bodies.
Rectangular polyomino set weak (1, 2)-achievement games

In a polyomino set (1, 2)-achievement game the maker and the breaker alternately mark one and two previously unmarked cells respectively. The maker's goal is to mark a set of cells congruent to one of a given set of polyominoes. The breaker tries to prevent the maker from achieving his goal. The teams of polyominoes for which the maker has a winning strategy is determined up to size 4. In set achievement games, it is natural to study infinitely large polyominoes. This enables the construction of super winners that characterize all winning teams up to a certain size.
Enantioselective intermolecular bromoesterification of allylic sulfonamides

Highly enantioselective intermolecular bromoesterification of alkenes was achieved for the first time. Both C–O and C–Br bonds were introduced enantioselectively in this olefin addition reaction. The sulfonamide NH directing group is important for both the reactivity and enantioselectivity.
Determination of action thresholds for electromagnetic tracking system-guided hypofractionated prostate radiotherapy using volumetric modulated arc therapy

Purpose: Hypofractionated prostate radiotherapy may benefit from both volumetric modulated arc therapy (VMAT) due to shortened treatment time and intrafraction real-time monitoring provided by implanted radiofrequency(RF) transponders. The authors investigate dosimetrically driven action thresholds (whether treatment needs to be interrupted and patient repositioned) in VMAT treatment with electromagnetic (EM) tracking. Methods: VMAT plans for five patients are generated for prescription doses of 32.5 and 42.5 Gy in five fractions. Planning target volume (PTV) encloses the clinical target volume (CTV) with a 3 mm margin at the prostate-rectal interface and 5 mm elsewhere. The VMAT delivery is modeled using 180 equi-spaced static beams. Intrafraction prostate motion is simulated in the plan by displacing the beam isocenter at each beam assuming rigid organ motion according to a previously recorded trajectory of the transponder centroid. The cumulative dose delivered in each fraction is summed over all beams. Two sets of 57 prostate motion trajectories were randomly selected to form a learning and a testing dataset. Dosimetric end points including CTV D95%, rectum wall D1cc, bladder wall D1cc, and urethra Dmax, are analyzed against motion characteristics including the maximum amplitude of the anterior-posterior (AP), superior-inferior (SI), and left-right components. Action thresholds are triggered whenmore » intrafraction motion causes any violations of dose constraints to target and organs at risk (OAR), so that treatment is interrupted and patient is repositioned. Results: Intrafraction motion has a little effect on CTV D95%, indicating PTV margins are adequate. Tight posterior and inferior action thresholds around 1 mm need to be set in a patient specific manner to spare organs at risk, especially when the prescription dose is 42.5 Gy. Advantages of setting patient specific action thresholds are to reduce false positive alarms by 25% when prescription dose is low, and increase the sensitivity of detecting dose limits violations by 30% when prescription dose is high, compared to a generic 2 mm action box. The sensitivity and specificity calculated from the testing dataset are consistent to the learning set, which indicates that the patient specific approach is reliable and reproducible within the scope of the prostate database. Conclusions: This work introduces a formalism for ensuring a VMAT delivery meets the most clinically important dose requirements by using patient specific and dosimetric-driven action thresholds to hold the beam and reposition the patient when necessary. Such methods can provide improved sensitivity and specificity compared to conventional methods, which assume directionally symmetric action thresholds.« less
On the reverse flow ceiling jet in pool fire-ventilation crossflow interactions in a simulated aircraft cabin interior

The behavior of the reverse flow ceiling jet against the ventilation flow from 0.58 to 0.87 m/s was investigated in a 1/3 scale model of a wide body aircraft interior. For all tests, strong reverse-flow ceiling jets of hot gases were detected well upstream of the fire. Both thicknesses of the reverse-flow ceiling jet and the smoke layer increased with the fire-crossflow parameter. The thickness of the smoke layer where the smoke flows along the main flow below the reverse-flow ceiling jet was almost twice that of the reverse-flow ceiling jet. Detailed spatial and time-varying temperatures of the gas in the test section were measured, and velocity profiles were also measured using a temperature compensated hot film.
The mean free path of low rigidity cosmic rays

A simple heuristic argument is presented which suggests that the large rigidity independent mean free paths observed for low rigidity solar and galactic cosmic rays can be understood in terms of weak turbulence diffusion theory if one assumes that the interplanetary magnetic turbulence consists of a combination of Alfven waves propagating with constant field magnitude and a small (approximately 5-10%) admixture of compressive fluctuations.
Protostellar Disk Evolution Over Million-Year Timescales With A Prescription For Magnetized Turbulence

Magnetorotational instability (MRI) is the most promising mechanism behind accretion in low-mass protostellar disks. Here we present the first analysis of the global structure and evolution of non-ideal MRI-driven T-Tauri disks on million-year timescales. We accomplish this in a 1+1D simulation by calculating magnetic diffusivities and utilizing turbulence activity criteria to determine thermal structure and accretion rate without resorting to a three-dimensional magnetohydrodynamical (MHD) simulation. Our major findings are as follows. First, even for modest surface densities of just a few times the minimum-mass solar nebula, the dead zone encompasses the giant planet-forming region, preserving any compositional gradients. Second, the surface density of the active layer is nearly constant in time at roughly 10 g cm–2, which we use to derive a simple prescription for viscous heating in MRI-active disks for those who wish to avoid detailed MHD computations. Furthermore, unlike a standard disk with constant-α viscosity, the disk midplane does not cool off over time, though the surface cools as the star evolves along the Hayashi track. Instead, the MRI may pile material in the dead zone, causing it to heat up over time. The ice line is firmly in the terrestrial planet-forming region throughout disk evolution and can move either inward or outward with time, depending on whether pileups form near the star. Finally, steady-state mass transport is an extremely poor description of flow through an MRI-active disk, as we see both the turnaround in the accretion flow required by conservation of angular momentum and peaks in bracketing each side of the dead zone. We caution that MRI activity is sensitive to many parameters, including stellar X-ray flux, grain size, gas/small grain mass ratio and magnetic field strength, and we have not performed an exhaustive parameter study here. Our 1+1D model also does not include azimuthal information, which prevents us from modeling the effects of Rossby waves.
Towards resolution of the scalar meson nonet enigma

By the application of a linear mass spectrum to a composite system of both the pseudoscalar and scalar meson nonets, we find three relations for the masses of the scalar states which suggest the $$q\bar q$$ assignment for the scalar meson nonet a0(1320), K 0 * (1430), f0(1500), and f0 ′(980).
Regulation of utero-placental prorenin.

Prorenin (Pro) is synthesized in a number of human utero-placental tissues, including chorion, decidua, villous placenta and probably mesenchymal cells. The release of Pro from these extra-renal tissues follows new protein synthesis and appears to utilize the constitutive secretory pathway. Unlike processing in the kidney, very little of the Pro is subsequently cleaved to the smaller product (active renin). Primary signals which regulate Pro include protein hormones and peptides (relaxin, endothelin, hCG), amines (epinephrine, norepinephrine, and related beta adrenergic agents), and eicosanoids. These agents increase the mRNA for prorenin at a time before peak secretory effects are noted. Other extracellular signals have negative regulatory effects. These include angiotensin, endotoxin and cyotkines (TNF-alpha and interleukin-1 B). There is also evidence that glucocorticoid receptor activation has an inhibitory effects on Pro release in placenta. Second messengers involved in the regulation of Pro include cyclic AMP and protein kinase A (PKA), protein kinase C (PKC), and calcium. The possible biological effect(s) of the extracellular Pro are unknown but may be due to direct generation of angiotensin I. Since angiotensin-peptides have a number of trophic effect on both vascular and non-vascular tissues, regulation of utero-placental Pro by autocrine, paracrine or endocrine signalling may be critical in normal fetal and/or placental development.
Does the Milky Way have a maximal disk

The Milky Way is often considered to be the best example of a spiral for which the dark matter not only dominates the outer kinematics but also plays a major dynamical role in the inner galaxy: the Galactic disk is therefore said to be submaximal. This conclusion is important to the understanding of the evolution of galaxies and the viability of particular dark matter models. The Galactic evidence rests on a number of structural and kinematic measurements, many of which have recently been revised. The new constraints not only indicate that the Galaxy is a more typical member of its class (Sb to Sc spirals) than previously thought but also require a reexamination of the question of whether the Milky Way disk is maximal. By applying to the Milky Way the same definition of maximal disk that is applied to external galaxies, it is shown that the new observational constraints are consistent with a Galactic maximal disk of reasonable M/L. In particular, the local disk column can be substantially less than the oft-quoted required Σ☉ ≈ 100 M☉ pc-2—as low as 40 M☉ pc-2 in the extreme case—and still be maximal, in the sense that the dark halo provides negligible rotation support in the inner Galaxy. This result has possible implications for any conclusion that rests on assumptions about the potential of the Galactic disk or dark halo and, in particular, for the interpretation of microlensing results along both LMC and bulge lines of sight.