cssi/SciSciGPT-SciSciNet huggingface dataset:
Has Welfare Reform Changed Teenage Behaviors

Data from the National Longitudinal Surveys of Youth 1979 and 1997 cohorts were used to compare welfare use, fertility, educational attainment, and marriage among teenage women in the years before and immediately following welfare reform. The first objective was to document differences between these cohorts in welfare use and outcomes and behavior correlated with entry into welfare and with future economic and social well-being. The second objective was to investigate the causal role of welfare reform in behavioral change. Significant differences were found between cohorts in welfare use and in outcomes related to welfare use. Furthermore, difference-in-differences estimates suggest that welfare reform has been associated with reduced welfare receipt, reduced fertility, and reduced marriage among young women who, because of a disadvantaged family background, are at high risk of welfare receipt. Finally, in the post-welfare reform era, teenage mothers are less likely to receive welfare and are more likely to live with at least one parent than in the pre-reform era. Establishing more definitively that welfare reform is responsible for these changes will require further investigation. © 2003 by the Association for Public Policy Analysis and Management.
A combinatorial Yamabe flow in three dimensions

A combinatorial version of Yamabe flow is presented based on Euclidean triangulations coming from sphere packings. The evolution of curvature is then derived and shown to satisfy a heat equation. The Laplacian in the heat equation is shown to be a geometric analogue of the Laplacian of Riemannian geometry, although the maximum principle need not hold. It is then shown that if the flow is nonsingular, the flow converges to a constant curvature metric.
QoS-aware multicasting in DiffServ domains

QoS-aware multicasting is becoming more and more desirable with the expanding usage of group-based applications, especially those involving multimedia objects. Until now, most of the proposed QoS-aware multicasting routing protocols adopt per-flow based resource reservation. Although these schemes can be adopted in integrated services (IntServ) Internet, they are not suitable for more scalable Differentiated Services (DiffServ) Internet. A new QoS-aware multicast routing protocol called QMD is proposed for DiffServ environments in this paper. Based on the design philosophy of DiffServ, the complex multicasting control plane functionalities are removed from the core routers. In addition, for each multicast group, only a limited set of on-tree routers (termed as key nodes) maintain multicast routing states and forward multicast data traffic. The key nodes of a multicast group uniquely identify a QoS-satisfied multicast tree connecting the group members. Although the other on-tree routers between any two key nodes do not maintain any multicast routing states and QoS reservation information, the group members' QoS requirements can still be satisfied. Through simulation experiments based on both random and real intra-domain topologies, we have also demonstrated that QMD can provide higher QoS-satisfaction rate while maintaining the simplicity of core routers.
Characteristics of Firms Responding to Underwater Employee Stock Options: Evidence from Traditional Repricings, 6&1 Exchanges, and Makeup Grants

ABSTRACT: I examine the characteristics of firms choosing to respond to underwater employee stock options using one of three stock‐option‐based responses. A traditional repricing offers a new and lower exercise price to restore the incentive alignment and retention power lost in underwater options, but is subject to potential expense recognition. A 6&1 exchange likewise restores what was lost in underwater options, but avoids potential expense recognition by delaying the issuance of replacement options until six months and one day later. A makeup grant potentially increases the total option value lost and avoids potential expense recognition, but is more dilutive since old underwater options are not cancelled. Results indicate that makeup grant firms have relatively deeper underwater options with shorter expected remaining lives. Makeup grant firms also issue these options to more non‐executives compared to traditional repricing firms. I also find that while both makeup grant and 6&1 exchange firms have l...
Time-Stampless Adaptive Nonuniform Sampling for Stochastic Signals

In this paper, we introduce a time-stampless adaptive nonuniform sampling (TANS) framework, in which time increments between samples are determined by a function of the m most recent increments and sample values. Since only past samples are used in computing time increments, it is not necessary to save sampling times (time stamps) for use in the reconstruction process. We focus on two TANS schemes for discrete-time stochastic signals: a greedy method, and a method based on dynamic programming. We analyze the performances of these schemes by computing (or bounding) their trade-offs between sampling rate and expected reconstruction distortion for autoregressive and Markovian signals. Simulation results support the analysis of the sampling schemes. We show that, by opportunistically adapting to local signal characteristics, TANS may lead to improved power efficiency in some applications.
External Electrical Termination of Supraventricular Arrhythmias in Congenital Heart Disease

Persistent supraventricular arrhythmias of the flutter or fibrillation-flutter type have been terminated by elective external electric countershock in three patients after drug therapy had been unsuccessful. It is suggested that this technic is a relatively safe and effective treatment for supraventricular as well as ventricular arrhythmias when anti-arrhythmic drugs have proved ineffective.
Synthesis of enantiomerically enriched imidazolidin-2-ones through asymmetric palladium-catalyzed alkene carboamination reactions

Positive water effect: A catalyst composed of [Pd(2)(dba)(3)] (dba=dibenzylideneacetone) and (S)-Siphos-PE is effective for the enantioselective coupling of N-allyl ureas with aryl bromides to afford 4-substituted imidazolidin-2-ones. Added water leads to significantly improved enantioselectivities with electron-poor aryl halide substrates. It is suggested that the C-C bond-forming reductive elimination is the enantiodetermining step in these reactions.
A Surface Flow Approach for Predicting Crosshatch Patterns

An analytical model based on liquid layer stability theory is used to predict the stability characteristics and geometric features of crosshatched ablation patterns. This approach postulates the formation of a melt or viscoelastic layer which interacts with the gas boundary layer. For supersonic flow, the dominant amplifying effect is found to be the component of the gas pressure perturbation acting in the valleys of the surface waves, while the dominant damping effect is the component of the gas shear perturbation acting on the wave slope. Solutions for the rate of amplification yield parameters that characterize pattern onset, wave angle, wavelength, and depth. Correlations with experimental data show reasonably good agreement. p g h Km M p Pmag Re t T UL x,y,z XN a p y F 6 5L e
Rule of Capture and Urban Sprawl: A Potential Federal Financial Risk in Groundwater-Dependent Areas

This paper illustrates the potential federal financial risk created by groundwater overabstraction, rapid urbanization, competing economic interests, and institutional arrangements in groundwater-dependent areas of Texas. In the Upper Trinity Groundwater Conservation District, located in the Dallas–Fort Worth metropolitan area, urban sprawl creates suburbanized rural areas reliant upon the Upper Trinity Aquifer. In the past 10 years, competition of economic interests for groundwater has intensified, as the area has experienced rapid urban sprawl combined with escalating Barnett Shale hydraulic fracturing activity, which coincided with two extreme droughts in 2006 and 2011. Urban sprawl generates business opportunities and tax revenues for state and local governments in the short term, but if groundwater overabstraction leads to land subsidence, financial risk is transferred to the federal government through increased risk exposure from federal housing loans and government-backed residential lending.
New probes of supersymmetry beyond the minimal framework

Abstract If supersymmetry is discovered at future colliders, what can we learn? While our appreciation of the variety of possible supersymmetric models has grown tremendously in recent years, most attempts to answer this question have been in the context of some simple and highly restrictive framework, such as minimal supergravity. In this talk I describe new probes of phenomena that are generic in models beyond the minimal framework. These include tests of supersymmetric flavor and CP violation and probes of kinematically inaccessible superparticle sectors through “super-oblique corrections.” Such probes have wide applicability to distinguishing models, from gravity- and gauge-mediated theories to hybrid models and models with flavor symmetries. Examples of measurements at LEP II, the LHC, and the NLC are given.
Stellar Rotation in M35: Mass-Period Relations, Spin-Down Rates, and Gyrochronology

We present the results of a five month photometric time-series survey for stellar rotation over a 40' × 40' field centered on the 150 Myr open cluster M35. We report rotation periods for 441 stars within this field and determine their cluster membership and binarity based on a decade-long radial velocity survey, proper-motion measurements, and multiband photometric observations. We find that 310 of the stars with measured rotation periods are late-type members of M35. The distribution of rotation periods for cluster members span more than 2 orders of magnitude from ~0.1 to 15 days, not constrained by the sampling frequency and the timespan of the survey. With an age between the zero-age main sequence and the Hyades, and with ~6 times more rotation periods than measured in the Pleiades, M35 permit detailed studies of early rotational evolution of late-type stars. Nearly 80% of the 310 rotators lie on two distinct sequences in the color-period plane, and define clear relations between stellar rotation period and color (mass). The M35 color-period diagram enables us to determine timescales for the transition between the two rotational states, of ~60 Myr and ~140 Myr for G and K dwarfs, respectively. These timescales are inversely related to the mass of the convective envelope, and offer constraints on the rates of internal and external angular momentum transport and of the evolution of stellar dynamos. A comparison to the Hyades, confirm the Skumanich spin-down dependence for G dwarfs on one rotational state, but suggest that K dwarfs spin down more slowly. The locations of the rotational sequences in the M35 color-period diagram support the use of rotational isochrones to determine ages for coeval stellar populations. We use such gyrochronology to determine gyro-ages for M35 from 134 Myr to 161 Myr. We use the M35 data to evaluate new color dependences for the rotational isochrones.
Enabling Correct Interest Forwarding and Retransmissions in a Content Centric Network

We show that the mechanisms used in the name data networking (NDN) and the original content centric networking (CCN) architectures may not detect Interest loops, even if the network in which they operate is static and no faults occur. Furthermore, we show that no correct Interest forwarding strategy can be defined that allows Interest aggregation and attempts to detect Interest looping by identifying Interests uniquely. We introduce SIFAH (Strategy for Interest Forwarding and Aggregation with Hop-Counts), the first Interest forwarding strategy shown to be correct under any operational conditions of a content centric network. SIFAH operates by having forwarding information bases (FIBs) store the next hops and number of hops to named content, and by having each Interest state the name of the requested content and the hop count from the router forwarding an Interest to the content. We present the results of simulation experiments using the ndnSIM simulator comparing CCN and NDN with SIFAH. The results of these experiments illustrate the negative impact of undetected Interest looping when Interests are aggregated in CCN and NDN, and the performance advantages of using SIFAH.
Perfect parallelepipeds exist

There are parallelepipeds with edge lengths, face diagonal lengths and body diagonal lengths that are all positive integers. In particular, there is a parallelepiped with edge lengths 271, 106, 103, minor face diagonal lengths 101, 266, 255, major face diagonal lengths 183, 312, 323, and body diagonal lengths 374, 300, 278, 272. Focused brute force searches give dozens of primitive perfect parallelepipeds. Examples include parallellepipeds with up to two rectangular faces.
A NEW CONSTRUCTION OF THE PENNER MODEL

The free energy of the Penner model is shown to be closely related to the integral over the two diagonalizing unitary matrices of a complex rectangular matrix.
Hydraulic actuator tuning in the control of a rotating flexible beam mechanism

The end point position and vibration control of rotating flexible beam mechanism driven by a hydraulic cylinder actuator are considered. An integrated nonlinear system model comprised of beam dynamics, hydraulic actuator, control valves, and control scheme is presented. Control based on simple position feedback, along with a hydraulic actuation system tuned to suppress beam vibration over a wide range of angular motion, is investigated. For positioning to small to moderate mechanism angles, a linear system model with the actuator tuned for good open-loop performance is developed. Actuator tuning is accomplished by varying the system hydraulic resistance according to a dimensionless parameter defining the interaction between actuator dynamics and the fundamental mode of the flexible beam. Simulation results for a closed-loop system indicate that this simple tuned control provides comparable performance and requires less control effort than an untuned system with a more complex state feedback optimal controller. To compensate for geometric nonlinearities that cause instability when positioning to large mechanism angles, an active actuator tuning scheme based on continuous variation of hydraulic resistance is proposed. The active variable resistance controller is combined with simple position feedback and designed to provide a constant dimensionless actuator-flexible beam interaction parameter throughout the motion. Simulation results are presented to show the stabilizing effect of this control strategy.
Synthetic Routes to Ninhydrins. Preparation of Ninhydrin, 5-Methoxyninhydrin, and 5-(Methylthio)Ninhydrin

Abstract Two syntheses of 5-methoxyninhydrin (2,2-dihydroxy-5-methoxy-1,3-indanedione) are described. One method employs a novel and efficient two step route, which begins with commercially available 6-methoxy-1-indanone. The application of this strategy for the preparation of a new ninhydrin derivative, 5-(methylthio)ninhydrin, and ninhydrin is also presented.
Thermodynamic properties of extended chain polymethylene single crystals

Density, morphology, and melting data on linear polyethylene and high molecular weight polymethylene crystallized from the melt under elevated pressure are presented. For approximately constant supercooling a sharp density increase is noted above 2300 atm. crystallization pressure. Above 4000 atm. densities above 0.99 are achieved. The high molecular weight polymethylene has larger lamellar thickness than polyethylene, but does not reach full chain extension. The melting of polymethylene is extremely sharp with no evidence of premelting up to at least 136°C. Equilibrium maximum melting points of 138.7 and 141.4°C. have been measured for polyethylene of 105 weight-average molecular weight and polymethylene of 107 molecular weight.
Normal coordinates and potential energy distributions of methyl acetylene and some halogen substituted analogues

Abstract The normal coordinates and potential energy distributions of methyl acetylene, methyl-d 3 acetylene and some halogen substituted analogues (CH 3 CCX; X = H, D, Cl, Br, I) have been calculated using previously determined force fields. For methyl chloro-acetylene, the chlorine-35,37 isotope frequency splitting has been calculated. In addition, for methyl acetylene, the harmonic frequencies were obtained and plotted for hypothetical molecules in which the mass of X varied from 1 to 1000 a.m.u. The frequencies for these molecules are compared and discussed.
Stellar Gas Flows into a Dark Cluster Potential at the Galactic Center

The evidence for the presence of a concentration of dark matter at the Galactic center (GC) is now very compelling. There is no question that the stellar and gas kinematics within ≈0.01 pc is dominated by underluminous matter in the form of either a massive black hole, a highly condensed distribution of stellar remnants, or a more exotic source of gravity. The unique, compact radio source Sgr A* appears to be coincident with the center of this region, but its size (less than about 6×1013 cm at λ7 mm) is still significantly smaller than the current limiting volume enclosing this mass. Sgr A* may be the black hole, if the dark matter distribution is pointlike. If not, we are left with a puzzle regarding its nature and a question of why this source should be so unique and lie only at the GC. In this paper, we examine an alternative to the black hole paradigm, that the gravitating matter is a condensed cluster of stellar remnants, and study the properties of the GC wind flowing through this region. Some of this gas is trapped in the cluster potential, and we study in detail whether this hot, magnetized gas is in the proper physical state to produce Sgr A*'s spectrum. We find that at least for the GC environment, the temperature of the trapped gas never attains the value required for significant GHz emission. In addition, continuum (mostly bremsstrahlung) emission at higher frequencies is below the current measurements for this source. We conclude that the cluster potential is too shallow for the trapped GC wind to account for Sgr A*'s spectrum, which instead appears to be produced only within an environment that has a steep-gradient potential like that generated by a black hole.
Housing price variability: national and local impacts

This article examines the influence of national and local forces on housing prices in 20 local US real estate markets during the recent housing price run-up and decline. We use reduced-form panel data fixed-effects models with robust SEs to determine the impact of national and local effects on housing prices in 20 US cities across time. A national home price index and mortgage rate are used to measure national impacts on the local markets. A mix of socio-economic variables estimates local impacts. We find no results indicating that national trends lack relevance in local markets; however, we find wide support for the additional inclusion of local socio-economic factors in all markets. The findings are consistent with an environment in which national polices and trends influence all markets; however local policymakers and investors can continue to expect geographic differences in market outcomes.
Symplectic Rigidity, Symplectic Fixed Points, and Global Perturbations of Hamiltonian Systems

In this paper we study a generalized symplectic fixed-point problem, first considered by J. Moser in [20], from the point of view of some relatively recently discovered symplectic rigidity phenomena. This problem has interesting applications concerning global perturbations of Hamiltonian systems. © 2007 Wiley Periodicals, Inc.
In-flight flow visualization using infrared imaging

A flight test investigation was conducted to evaluate infrared (IR) flow imaging techniques for boundary-layer flow visualization. The flight tests used a single-engine turboprop aircraft with a fiberglass-skinned natural laminar flow glove mounted on the left wing and an infrared imaging system to obtain flow visualization data. Data were compared to results obtained from other more conventional boundary-layer flow visualization methods and found to agree well. Test flights were conducted to determine the effect of test surface color on IR flow visualization results. In addition, flights were made during both night and daylight hours to assess the effect of solar radiation on the results. The investigation included an effort to visualize a vortex passing over the wing glove, but the tests provided only limited results.
Simultaneous compensation of input and state delays for nonlinear systems

Abstract The problem of compensation of arbitrary large input delay for nonlinear systems was solved recently with the introduction of the nonlinear predictor feedback. In this paper we solve the problem of compensation of input delay for nonlinear systems with simultaneous input and state delays of arbitrary length. The key challenge, in contrast to the case of only input delay, is that the input delay-free system (on which the design and stability proof of the closed-loop system under predictor feedback are based) is infinite-dimensional. We resolve this challenge and we design the predictor feedback law that compensates the input delay. We prove global asymptotic stability of the closed-loop system using two different techniques—one based on the construction of a Lyapunov functional, and one using estimates on solutions. We present two examples, one of a nonlinear delay system in the feedforward form with input delay, and one of a scalar, linear system with simultaneous input and state delays.
Near-optimal no-regret algorithms for zero-sum games

Abstract We propose a new no-regret learning algorithm. When used against an adversary, our algorithm achieves average regret that scales optimally as O ( 1 T ) with the number T of rounds. However, when our algorithm is used by both players of a zero-sum game, their average regret scales as O ( ln ⁡ T T ) , guaranteeing a near-linear rate of convergence to the value of the game. This represents an almost-quadratic improvement on the rate of convergence to the value of a zero-sum game known to be achievable by any no-regret learning algorithm. Moreover, it is essentially optimal as we also show a lower bound of Ω ( 1 T ) for all distributed dynamics, as long as the players do not know their payoff matrices in the beginning of the dynamics. (If they did, they could privately compute minimax strategies and play them ad infinitum.)
Broad-band impedance matching of the RLC generator and load

Abstract This paper presents a simple theory for the design of a broad-band impedance matching network which, when operating between a given RLC generator z 1 (s) and an RLC load z 2 (s), yields a Chebyshev low-pass or band-pass response. Using realizability conditions of double frequency-dependent terminations, we present a new theorem which states that if there exists a second-order all-pass function such that the resulting reflection coefficients are bounded-real and satisfy Youla's conditions at each zero of transmission of z 1 (s) and z 2 (s), a ladder equalizer exists. A method to realize such a ladder is described. After choosing the order n of the transfer function not smaller than the total number of the energy storage elements of z 1 (s) and z 2 (s), the result can easily be extended to any all-pole low-pass response for any non-Foster positive-real impedances z 1 (s) and z 2 (s) except for the case where z 1 (s) and z 2 (s) have a common finite zero on the j ω-axis.
Analysis and design of two stretched-membrane parabolic dish concentrators

Analytic models used to evaluate the performance of the single-element stretched-membrane dish and the several configurations for the faceted stretched-membrane dish and the results obtained are presented. The designs of the two stretched-membrane dish development projects are described too
Aeroelastic stability of periodic systems with application to rotor blade flutter

The dynamics of a helicopter blade in forward flight are described by a system of linear differential equations with periodic coefficients. The stability of this periodic aeroelastic system is determined, using multivariable Floquet-Liapunov theory. The transition matrix at the end of the period is evaluated by: (1) direct numerical integration, and (2) a new, approximate method, which consists in approximating a periodic function by a series of step functions. The numerical accuracy and efficiency of the methods is compared, and the second method is shown to be superior by far. Results illustrating the effect of the periodic coefficients and various blade parameters are presented.
Spin Resonance Strength Calculations

In calculating the strengths of depolarizing resonances it may be convenient to reformulate the equations of spin motion in a coordinate system based on the actual trajectory of the particle, as introduced by Kondratenko, rather than the conventional one based on a reference orbit. It is shown that resonance strengths calculated by the conventional and the revised formalisms are identical. Resonances induced by radiofrequency dipoles or solenoids are also treated; with rf dipoles it is essential to consider not only the direct effect of the dipole but also the contribution from oscillations induced by it.
Excited state quantum-classical molecular dynamics

We are focusing on developing a predictive theoretical, algorithmic and computational framework describing the many-body dynamics of the plasma–wall interactions by applying multiscale quantum-classical (QC) molecular dynamics (MD) and quantum chemistry approaches. Computer simulations of the dynamics of molecular systems often encounter serious limitations, of both phenomenological and quantitative nature, due to our inability to treat non-adiabatic transition dynamics and evolution beyond the ground Born–Oppenheimer electronic surface. This is, in particular, present due to charge transfer, collisional-cascade excitations and chemical sputtering of plasma ions impinging on a plasma-facing surface. A quantum mechanical treatment of the full non-adiabatic multibody dynamics is not currently feasible. To address existing deficiencies in knowledge of non-adiabatic MD, we propose excited state many-body dynamics by considering multiphysics described by time-dependent versions of the mean-field theories as well as QC Liouville equations, combined with multiresolution techniques for solving the quantum part of the problem.
Bias error reduction using ratios to baseline experiments - Heat transfer case study

Concluding Remarks In this study, numerical simulations by means of a finite difference method have been performed to render the effects of the relevant physical parameters of the problem considered (Re, Gr, and (/>) on the interaction between the shear-driven flow and the buoyant recirculating flow during the heating process of the moving plate. Results indicate that the sheardriven flowfields in the divided subchannels can be strongly affected by the buoyancy force due to an increase of Grashof number; a bicellular recirculation arises respectively within the subchannels in the region around the heaters. Moreover, an increase in Grashof number tends to promote the upstream diffusion effect due to the buoyant recirculation, particularly for the upper channel. Accordingly, the local Nusselt number on the top surface of the moving plate becomes less localized shifting in the upstream direction. Moreover, the flowfield and temperature distribution in the upper subchannel are found to be more sensitive to the inclination of the duct. For the range of inclination considered, the temperature as well as the heat transfer on the moving plate are rather unaffected by the variation of the duct orientation.
A new uranyl niobate sheet in the cesium uranyl niobate Cs9[(UO2)8O4(NbO5)(Nb2O8)2]

A new cesium uranyl niobate, Cs{sub 9}[(UO{sub 2}){sub 8}O{sub 4}(NbO{sub 5})(Nb{sub 2}O{sub 8}){sub 2}] or Cs{sub 9}U{sub 8}Nb{sub 5}O{sub 41} has been synthesized by high-temperature solid-state reaction, using a mixture of U{sub 3}O{sub 8}, Cs{sub 2}CO{sub 3} and Nb{sub 2}O{sub 5}. Single crystals were obtained by incongruent melting of a starting mixture with metallic ratio=Cs/U/Nb=1/1/1. The crystal structure of the title compound was determined from single crystal X-ray diffraction data, and solved in the monoclinic system with the following crystallographic data: a=16.729(2) A, b=14.933(2) A, c=20.155(2) A{beta}=110.59(1){sup o}, P2{sub 1}/c space group and Z=4. The crystal structure was refined to agreement factors R{sub 1}=0.049 and wR{sub 2}=0.089, calculated for 4660 unique observed reflections with I{>=}2{sigma}(I), collected on a BRUKER AXS diffractometer with MoK{alpha} radiation and a CCD detector. In this structure the UO{sub 7} uranyl pentagonal bipyramids are connected by sharing edges and corners to form a uranyl layer {sub {infinity}}{sup 2}[U{sub 8}O{sub 36}] corresponding to a new anion-sheet topology, and creating triangular, rectangular and square vacant sites. The two last sites are occupied by Nb{sub 2}O{sub 8} entities and NbO{sub 5} square pyramids, respectively, to form infinite uranyl niobate sheets {sub {infinity}}{sup 2}[(UO{sub 2}){sub 8}O{sub 4}(NbO{sub 5})(Nb{sub 2}O{sub 8}){submore » 2}]{sup 9-} stacking along the [010] direction. The Nb{sub 2}O{sub 8} entities result from two edge-shared NbO{sub 5} square pyramids. The Cs{sup +} cations are localized between layers and ensured the cohesion of the structure. The cesium cation mobility between the uranyl niobate sheets was studied by electrical measurements. The conductivity obeys the Arrhenius law in all the studied temperature domains. The observed low conductivity values with high activation energy may be explained by the strong connection of the Cs{sup +} cations to the infinite uranyl niobate layers and by the high density of these cations in the interlayer space without vacant site. Infrared spectroscopy investigated at room temperature in the frequency range 400-4000 cm{sup -1}, showed some characteristic bands of uranyl ion and niobium polyhedra. - Graphical abstract: View of the {sub {infinity}}{sup 2}[U{sub 8}O{sub 36}] uranyl infinite layer formed by association of [U{sub 6}O{sub 30}] and [U{sub 2}O{sub 12}] uranyl blocks in Cs{sub 9}[(UO{sub 2}){sub 8}O{sub 4}(NbO{sub 5})(Nb{sub 2}O{sub 8}){sub 2}].« less
Asymptotic behavior of individual orbits of discrete systems

We consider the asymptotic behavior of bounded solutions of the difference equations of the form x(n + 1) = Bx(n) + y(n) in a Banach space X, where n = 1,2,..., B is a linear continuous operator in X, and (y(n)) is a sequence in X converging to 0 as n → ∞. An obtained result with an elementary proof says that if σ(B) ∩ {|z| = 1} ⊂ {1}, then every bounded solution x(n) has the property that lim n →∞ (x(n + 1) - x(n)) = 0. This result extends a theorem due to Katznelson-Tzafriri. Moreover, the techniques of the proof are furthered to study the individual stability of solutions of the discrete system. A discussion on further extensions is also given.
Collective modes of massive Dirac fermions in armchair graphene nanoribbons.

We report the plasmon dispersion characteristics of intrinsic and extrinsic armchair graphene nanoribbons of atomic width N = 5 using a pz-orbital tight binding model with third-nearest-neighbor (3nn) coupling. The hopping parameters are obtained by fitting the 3nn dispersions to those of an extended Huckel theory. The resultant massive Dirac fermion system has a band gap Eg ≈ 64 meV. The extrinsic plasmon dispersion relation is found to asymptotically approach a universal dispersion curve as the chemical potential μ increases, whereas the intrinsic plasmon dispersion relation is found to have both energy and momentum thresholds. We also report an analytical model for the extrinsic plasmon group velocity in the q → 0 limit.
Environmental Controls and Immunotherapy in the Treatment of Chronic Asthma

(1990). Environmental Controls and Immunotherapy in the Treatment of Chronic Asthma. Journal of Asthma: Vol. 27, No. 5, pp. 277-289.
SIMULATION OF PHOSPHORUS IMPLANTATION INTO SILICON WITH A SINGLE PARAMETER ELECTRONIC STOPPING POWER MODEL

We simulate dopant profiles for phosphorus implantation into silicon using a new model for electronic stopping power. In this model, the electronic stopping power is factorized into a globally averaged effective charge , and a local charge density dependent electronic stopping power for a proton. There is only a single adjustable parameter in the model, namely the one electron radius which controls . By fine tuning this parameter, we obtain excellent agreement between simulated dopant profiles and the SIMS data over a wide range of energies for the channeling case. Our work provides a further example of implant species, in addition to boron and arsenic, to verify the validity of the electronic stopping power model and to illustrate its generality for studies of physical processes involving electronic stopping.
Optimal nonlinear, but continuous, feedback control of systems with saturating actuators

This paper presents a modification of the optimal saturating feedback control laws given by Frankena and Sivan (1979) and Ryan (1982 a) for asymptotically stable systems. Unlike their results, which involve bang-bang action and singular extremals, the modified control law is continuous. Specifically, the new control law is linear inside a cylinder set and saturated elsewhere. Using steady-state Hamilton-Jacobi-Bellman theory, this control law is shown to be optimal for a modified performance functional with a discontinuous integrand.
ON MARKOV'S THEOREM

Let χ be an oriented link type in the oriented 3-sphere S3 or ℝ3 = S3 - {∞}. A representative X ∈ χ is said to be a closed braid if there is an unknotted curve A ⊂ S3 - X (the axis) and a choice of fibration ℋ of the open solid torus S3 - A by meridian discs {Hθ : θ ∈ [0, 2 π]}, such that whenever X meets a fiber Hθ the intersection is transverse. Closed braid representations of χ are not unique, and Markov's well-known theorem asserts that any two are related by a finite sequence of elementary moves. The main result in this paper is to give a new proof of Markov's theorem. We hope that our new proof will be of interest because it gives new insight into the geometry.
A Rhodium(I)-Catalyzed Demethylation−Cyclization of o-Anisole-Substituted Ynamides in the Synthesis of Chiral 2-Amido Benzofurans§

A Rh(I)-catalyzed demethylation−cyclization sequence for a direct transformation of o-anisole-substituted ynamides to benzofurans is described here. The Ag salt functions synergistically with Rh(I) for the key demethylation step.
An inverse problem for a heat equation with piecewise- constant thermal conductivity

The governing equation is u t =axu xx ,0 x1, t0, ux,0=0, u0,t=0, a1u1,t=ft. The extra data are u1,t=gt. It is assumed that ax is a piecewise-constant function and f0. It is proved that the function ax is uniquely defined by the above data. No restrictions on the number of discontinuity points of ax and on their locations are made. The number of discontinuity points is finite, but this number can be arbitrarily large. If axC 2 0,1, then a uniqueness theorem has been established earlier for multidimensional problem, x R n ,n1 see A. G. Ramm, Multidimensional inverse problems and completeness of the products of solutions to PDE, J. Math. Anal. Appl., 134 ,2 111988 for the stationary problem with infinitely many boundary data. The novel point in this work is the treatment of the discontinuous piecewise-constant function ax and the proof of Property C for a pair of the operators 1,2, where j ad 2 /dx 2 +k 2 qj 2 x, j
Sexual Behavior in Pregnancy

This chapter reports on a study of the sexuality of pregnant women. In general, the results showed a linear decrease in sexual interest, frequency of coitus, and frequency of orgasm over the course of pregnancy. These results should be viewed with caution, however, for a number of reasons. First, this is a retrospective study. Within a few days of delivery, women were asked to recall their sexual patterns over the course of their pregnancy. Such retrospective reports of events in the distant past are often distorted by selective memory and by the active memory of more recent events. Since the subjects were generally physically uncomfortable and therefore uninterested in sex during the ninth month of their pregnancy, their reports of decreased sexual activity during the first months of pregnancy may have been influenced by this recent memory. Secondly, the interviewers were all young males. It is reasonable to expect that many women, immediately after delivery, would be reluctant to describe themselves as highly interested in sex to young male strangers.
Did the Clean Air Act cause the remarkable decline in sulfur dioxide concentrations

Over the last three decades, ambient concentrations of sulfur dioxide (SO2) air pollution have declined by approximately 80%. This paper tests whether the 1970 Clean Air Act and its subsequent amendments caused this decline. The centerpiece of this legislation is the annual assignment of all counties to SO2 nonattainment or attainment categories. Polluters face stricter regulations in nonattainment counties. There are two primary findings. First, regulators pay little attention to the statutory selection rule in their assignment of the SO2 nonattainment designations. Second, SO2 nonattainment status is associated with modest reductions in SO2 air pollution, but a null hypothesis of zero effect generally cannot be rejected. This finding holds whether the estimated effect is obtained with linear adjustment or propensity score matching. Overall, the evidence suggests that the nonattainment designation played a minor role in the dramatic reduction of SO2 concentrations over the last 30 years.
Families of simply connected 4-manifolds with the same Seiberg-Witten invariants

Abstract This article presents several new constructions of infinite families of smooth 4-manifolds with the property that any two manifolds in the same family are homeomorphic. While the construction gives strong evidence that any two of these manifolds of are not diffeomorphic, they cannot be distinguished by Seiberg–Witten invariants. Whether these manifolds are, or are not, diffeomorphic seems to be a very difficult question to answer. For one of these constructions, each member of the family is symplectic with the further property that each contains nullhomologous tori with the property that infinitely many log transformations on these tori yield nonsymplectic 4-manifolds. This is detected by calculations of Seiberg–Witten invariants. The surgery in question can be performed on any 4-manifold which contains as a codimension 0 submanifold a punctured surface bundle over a punctured surface and a nontrivial loop in the base which has trivial monodromy. A starting point for another class of examples in this paper is a family of examples which show that the Parshin–Arakelov theorem for holomorphic Lefschetz fibrations is false in the symplectic category. Such families are constructed by means of knot surgery on ellipitic surfaces. It is shown that for a fixed homeomorphism type X (of a simply connected elliptic surface) and a fixed integer g⩾3, there are infinitely many genus g Lefschetz fibrations on nondiffeomorphic 4-manifolds, all homeomorphic to X.
Initial uncertainty and the risk of setting a fixed-offer price: Implications for the pricing of bookbuilt and best-efforts IPOs

Abstract We model the risk of setting the required fixed-offer price in an IPO given initial uncertainty about value, as well as costs of over and underpricing. Assuming that the goal of issuers in bookbuilt IPOs is to maximize net offering proceeds, our analysis indicates that their optimal strategy is to negotiate a relatively small spread, consistent with material underpricing. Similarly, considering the expected costs of overpricing makes the underpricing of best-efforts IPOs in the interest of issuers. Our results rely on neither asymmetric information nor agency costs and provide support for Hansen's (2001) nearly-optimal “conventional” spread and the view that it evolved from adaptive, imitative behavior, consistent with Alchian's (1950) explanation of how economic players evolve practices to survive under uncertainty and incomplete information, as well as Alchian's (1969) work on how fixed prices and queues can efficiently clear product markets.
Compression equations for mercury porosimetry

Abstract Equations, related to mercury porosimetry, which describe the volume effects of the compressions of the penetrometer, the mercury, and a nonporous sample were derived in this work and were found to be consistent with relations given by past workers. Isothermal compressions of four liquids were determined utilizing an Aminco 103 MPa (15,000 psi) porosimeter. These compressions, fitted to the Tait equation, agreed well with compressions calculated from Tait parameters in the literature. An equation for the filled pore volume of a porous compressible solid (as a function of pressure) was also derived and demonstrated in this work. Using literature values of the Tait parameters of a given material, this equation was used to correctly calculate the pore volumes of four different solids. Surface areas calculated from corrected pore volumes were found to agree well with B.E.T. surface areas when a contact angle of 180° was used for macroporous samples having rough surfaces.
Food firms and food flows in Japan 1945-98.

Abstract Japan's food capitals in food processing, retailing, and services have grown to rank among the world's largest companies in three stages over the past 50 years. In each stage, firms have increased the import content of their products and expanded their interdependencies with foreign firms. This paper traces the growth and survival strategies of four firms: Ajinomoto, Kikkoman, Kirin Brewery, and Nissin Food Products. Production abroad for markets abroad is not a new trend, but is more globally extensive in recent years.
Pricing of Multi‐Defaultable Bonds with a Two‐Correlated‐Factor Hull–White Model

This research attempts to propose closed‐form solutions for prices of credit‐risky bonds, assuming a nonzero correlation between interest rates and credit spreads. The times of default of a credit‐risky bond are modelled as the jump times of a Cox process, following the method of Lando, with an intensity that follows a Hull and White model, correlated with a similar model of the risk‐free interest rate. Under the fractional recovery of market value assumption of Duffie and Singleton, the partial differential equation (PDE) for the price of the zero‐coupon credit‐risky bond is derived. Then this PDE is analytically solved, using the method of separation of variables, and easy‐to‐implement closed‐form solutions are found. Finally, numerical examples are presented to show how these closed‐form solutions can identify the magnitude and the direction of the credit‐risky bond mispricing under different parameter assumptions.
Three-Component Coupling Reactions of Silylglyoxylates, Alkynes, and Aldehydes: A Chemoselective One-Step Glycolate Aldol Construction

A single-pot three-component coupling reaction of silylglyoxylates (1), terminal alkynes, and aldehydes in the presence of ZnI2 and Et3N is presented. The products of the reaction, densely functionalized silyl-protected glycolate aldols (2), can be converted to the corresponding acetonides (3) in a one-pot deprotection/ketalization sequence. A variety of terminal alkynes and aldehydes can be successfully employed to give a range of highly functionalized, fully protected 1,2-diols in good yields and moderate diastereoselectivities. Mechanistic experiments suggest that the zinc acetylide reacts with the silylgyloxylate (1) in a chemoselective manner. Using an unoptimized (+)-N-methylephedrine and Zn(OTf)2 system, silyl-deprotected adduct 2 was formed in 64% ee and 89:11 dr.
A Fortran code for null geodesic solutions in the Lemaı̂tre–Tolman–Bondi spacetime

Abstract This paper describes the Fortran 77 code SIMU , version 1.1, designed for numerical simulations of observational relations along the past null geodesic in the Lemaitre–Tolman–Bondi (LTB) spacetime. SIMU aims at finding scale invariant solutions of the average density, but due to its full modularity it can be easily adapted to any application which requires LTB's null geodesic solutions. In version 1.1 the numerical output can be read by the GNUPLOT plotting package to produce a fully graphical output, although other plotting routines can be easily adapted. Details of the code's subroutines are discussed, and an example of its output is shown.
Geometric Langlands duality and representations of algebraic groups over commutative rings

As such, it can be viewed as a first step in the geometric Langlands program. The connected complex reductive groups have a combinatorial classification by their root data. In the root datum the roots and the co-roots appear in a symmetric manner and so the connected reductive algebraic groups come in pairs. If G is a reductive group, we write G for its companion and call it the dual group G. The notion of the dual group itself does not appear in Satake's paper, but was introduced by Langlands, together with its various elaborations, in [LI], [L2] and is a cornerstone of the Langlands program. It also appeared later in physics [MO], [GNO]. In this paper we discuss the basic relationship between G and G. We begin with a reductive G and consider the affine Grassmannian Qx, the Grassmannian for the loop group of G. For technical reasons we work with formal algebraic loops. The affine Grassmannian is an infinite dimen sional complex space. We consider a certain category of sheaves, the spherical perverse sheaves, on ?r. These sheaves can be multiplied using a convolution product and this leads to a rather explicit construction of a Hopf algebra, by what has come to be known as Tannakian formalism. The resulting Hopf algebra turns out to be the ring of functions on G. In this interpretation, the spherical perverse sheaves on the affine Grassman nian correspond to finite dimensional complex representations of G. Thus, instead of defining G in terms of the classification of reductive groups, we pro vide a canonical construction of G, starting from G. We can carry out our construction over the integers. The spherical perverse sheaves are then those with integral coefficients, but the Grassmannian remains a complex algebraic object.
A supersymmetric theory of vector-like leptons

We study a supersymmetric extension of the vector-like lepton scenario, such that the vacuum instability induced by large lepton Yukawa couplings is lifted by the presence of superpartners at or below the TeV scale. In order to preserve the unification of gauge couplings, we introduce a full $ 16+\overline{16} $ of SO(10), and determine the maximal possible values for the Yukawa couplings consistent with perturbativity at the GUT scale. We find that the Higgs to diphoton decay rate can be enhanced by up to 50% while maintaining vacuum stability and keeping the new particle masses above 100 GeV, while larger enhancements are possible if the masses of the new particles are lowered further.