cssi/SciSciGPT-SciSciNet huggingface dataset:
On predictive modeling for optimizing transaction execution in parallel OLTP systems

A new emerging class of parallel database management systems (DBMS) is designed to take advantage of the partitionable workloads of on-line transaction processing (OLTP) applications [23, 20]. Transactions in these systems are optimized to execute to completion on a single node in a shared-nothing cluster without needing to coordinate with other nodes or use expensive concurrency control measures [18]. But some OLTP applications cannot be partitioned such that all of their transactions execute within a single-partition in this manner. These distributed transactions access data not stored within their local partitions and subsequently require more heavy-weight concurrency control protocols. Further difficulties arise when the transaction's execution properties, such as the number of partitions it may need to access or whether it will abort, are not known beforehand. The DBMS could mitigate these performance issues if it is provided with additional information about transactions. Thus, in this paper we present a Markov model-based approach for automatically selecting which optimizations a DBMS could use, namely (1) more efficient concurrency control schemes, (2) intelligent scheduling, (3) reduced undo logging, and (4) speculative execution. To evaluate our techniques, we implemented our models and integrated them into a parallel, main-memory OLTP DBMS to show that we can improve the performance of applications with diverse workloads.
Urinary concentrations of bisphenol A in an urban minority birth cohort in New York City, prenatal through age 7 years.

Background Despite growing concern over potential health effects associated with exposures to the endocrine disruptor, bisphenol A (BPA), insufficient information is available on determinants of BPA concentrations among minority populations in the US.
Tick size, NYSE rule 118, and ex-dividend day stock price behavior

Abstract Bali and Hite (1998) and Dubofsky (1992) propose models in which market microstructure effects play a role in the ex-dividend day price drop anomaly. Bali and Hite suggest that the anomaly is caused solely by price discreteness, while Dubofsky suggests that NYSE Rule 118 is also involved. We test these models by examining cum- to ex-day price drops during the one-eighth, one-sixteenth, and decimal tick size regimes. While the evidence is qualitatively consistent with Dubofsky's predictions, neither model is satisfactory in a quantitative sense. One of our main empirical findings is that no significant decline was evident in the magnitude of the ex-day anomaly after the tick size reduction.
Vapor Pressure and Heat of Sublimation of Rhenium.

The vapor pressure of rhenium was measured by the Langmuir method in the temperature range 2350-3050 °K using a vacuum microbalance. The least squares line through the four series of data points is 4.5756 log P(atm) = 32.26 - 180700/T. Least squares lines for each of the four series yield heats and entropies of sublimation higher than the corresponding third law values. The vapor pressure equation based on the average heat and entropy is, 4.5756 log P(atm) = 33.36 - 183500/T. The selected third law heat of sublimation, Δ H s ° (298) is 185.9 kcal mol-1. Our recommended equation for the vapor pressure is 4.5756 log P (atm) = 31.86 - 180200/T based on our mean third law heat and tabulated values for the entropies and enthalpies.
Approximating ground and excited state energies on a quantum computer

Approximating ground and a fixed number of excited state energies, or equivalently low-order Hamiltonian eigenvalues, is an important but computationally hard problem. Typically, the cost of classical deterministic algorithms grows exponentially with the number of degrees of freedom. Under general conditions, and using a perturbation approach, we provide a quantum algorithm that produces estimates of a constant number $$j$$j of different low-order eigenvalues. The algorithm relies on a set of trial eigenvectors, whose construction depends on the particular Hamiltonian properties. We illustrate our results by considering a special case of the time-independent Schrodinger equation with $$d$$d degrees of freedom. Our algorithm computes estimates of a constant number $$j$$j of different low-order eigenvalues with error $$O(\varepsilon )$$O(?) and success probability at least $$\frac{3}{4}$$34, with cost polynomial in $$\frac{1}{\varepsilon }$$1? and $$d$$d. This extends our earlier results on algorithms for estimating the ground state energy. The technique we present is sufficiently general to apply to problems beyond the application studied in this paper.
Electronic Polaron Effects in Mixed Valence and Heavy Fermion Materials

It is shown that the Coulomb interaction between f electrons and broad band electrons has a profound influence on the dynamical properties of an f hole in mixed valence and heavy fermion materials. At zero temperature the dynamics of the screening process contains an infrared divergence. The broadening of this divergence by temperature causes the motion of the f electrons to crossover from wave propagation to diffusion. This mechanism explains the observed dual nature of the f electrons, namely that at low temperatures they behave like a Fermi liquid, while at high temperatures they evolve into a lattice of localized magnetic moments.
A new mononuclear thiolato nickel(II) square planar complex with an uncommon (S2NO) coordination

Abstract The synthesis, structure, spectra and properties of (Ph4P)[Ni(MSA)(SPh)] (tetraphenylphosphonium 2-(2-mercaptophenyl)salicyladiminato thiophenolato nickelate(II)) (I) are reported. The compound crystallizes as red needles in the monoclinic spaces group P21/c with cell dimensions a = 10.813(6), b = 17.061(6), c = 19.873(10) A, β = 100.06(5)°, V = 3610(3) A3, Z = 4. The structure was solved by conventional methods using 4919 reflections and refined to R = 5.7% and Rw = 6.6%. The complex features a square planar Ni2+ environment in which the metal center is bound to two sulfur, a nitrogen an an oxygen atom. The corresponding phenolato complex (Ph4P)[Ni(MSA)(OPh)] (II) is X-ray isomorphous to I. The electronic spectra and electrochemical properties of I and II are discussed.
A theoretical prediction of the acoustic pressure generated by turbulence-flame front interactions

The equations of momentum and continuity are combined and linearized yielding the one dimensional nonhomogeneous acoustic wave equation. Three terms in the non-homogeneous equation act as acoustic sources and are taken to be forcing functions acting on the homogeneous wave equation. The three source terms are: fluctuating entropy, turbulence gradients, and turbulence-flame interactions. Each source term is discussed. The turbulence-flame interaction source is used as the basis for computing the source acoustic pressure from the Fourier transformed wave equation. Pressure fluctuations created in turbopump gas generators and turbines may act as a forcing function for turbine and propellant tube vibrations in earth to orbit space propulsion systems and could reduce their life expectancy. A preliminary assessment of the acoustic pressure fluctuations in such systems is presented.
The influence of aeration intensity on predation and EPS production in membrane bioreactors

Shear, in the form of vigorous aeration, is used to control fouling in membrane bioreactor (MBR) systems. However, shear also influences the physicochemical and biological properties of MBR biomass. The current study examines the relationship between the aeration intensity and extracellular polymeric substance (EPS) production in MBRs. Two identical submerged MBRs were operated in parallel but the aeration rate was three times greater in one of the MBRs. The concentrations of floc-associated and soluble EPS were monitored for the duration of the experiment. Microscopic images and floc-size measurements were also collected regularly. The membrane fouling potential of the biomass was quantified using the flux-step method. Increased aeration did not have a direct effect on soluble or floc-associated EPS production in the microfiltration MBRs. However, aeration intensity had a significant effect on predatory organisms. Large aquatic earthworms, Aeolosoma hemprichi, proliferated under lower shear conditions but were never observed in the high shear reactor. Predation by A. hemprichi resulted in increased floc-associated and soluble EPS production. Thus, the mixing conditions in the low shear MBR indirectly resulted in increased soluble EPS concentrations and higher fouling potential. This research suggests that predation can have a significant impact on the production rates of floc-associated and soluble EPS – key parameters driving membrane fouling in MBRs.
Fast selection of N−2 contingencies for online security assessment

We propose a novel algorithm for selection of dangerous N-2 contingencies associated with line or generator failures. The algorithm is based on iterative filtering of the set of all possible double contingencies. It is certified to identify all the dangerous contingencies, and has the complexity comparable to the N-1 contingency screening. Tests performed on realistic model of Polish power grid with about 3000 buses show that only two iterations of algorithm allow one to certify the safety of 99.9% of all double contingencies, leaving only 0.1% of the most dangerous ones for direct analysis.
Galaxies on the Blue Edge

We have successfully constructed a catalog of H I–rich galaxies selected from the Minnesota Automated Plate Scanner catalog of the Palomar Observatory Sky Survey (POSS I*), based solely on optical criteria. We identify H I–rich candidates by selecting the bluest galaxies at a given apparent magnitude, those galaxies on the blue edge of POSS I color-magnitude parameter space. Subsequent 21 cm observations on the upgraded Arecibo 305 m dish detected over 50% of the observed candidates. The detected galaxies are H I–rich, with H I masses comparable to "normal" high surface brightness disk galaxies, and they have gas mass-to-light ratios ranging from 0.1 to 4.8 (in solar units). Comparison of our candidate galaxies with known low surface brightness galaxies (hereafter LSBs) shows that they exhibit similar optical and H I properties to that population. We also show that previously identified LSBs, including several LSBs with red B-V colors, preferentially occupy the blue edge of POSS I color-magnitude parameter space. Their presence on the blue edge appears to be a selection effect due to differing plate limits in the two POSS I bandpasses. This suggests the POSS I is a good filter for separating galaxies on the higher surface brightness end of the LSB population from the general population of galaxies in the night sky.
Convexity of Hessian integrals and Poincaré type inequalities

In this paper, we studied integrals involving both real and complex Hessian operators over bounded domain. Poincare type inequalities were proved in both cases which generalized a early results of Trudinger and Wang.
Linear programming bounds for unitary space time codes

The linear programming method is applied to the space Un(Copf) of unitary matrices in order to obtain bounds for codes relative to the diversity sum and the diversity product. Theoretical and numerical results improving previously known bounds are derived.
On a theorem of Peter Scott

We quantify Peter Scott's Theorem that surface groups are locally extended residually finite (LERF) in terms of geometric data. In the process, we will quantify another result by Scott that any closed geodesic in a surface lifts to an embedded loop in a finite cover.
Exploring the Tradeoffs between Programmability and Efficiency in Data-Parallel Accelerators

We present a taxonomy and modular implementation approach for data-parallel accelerators, including the MIMD, vector-SIMD, subword-SIMD, SIMT, and vector-thread (VT) architectural design patterns. We introduce Maven, a new VT microarchitecture based on the traditional vector-SIMD microarchitecture, that is considerably simpler to implement and easier to program than previous VT designs. Using an extensive design-space exploration of full VLSI implementations of many accelerator design points, we evaluate the varying tradeoffs between programmability and implementation efficiency among the MIMD, vector-SIMD, and VT patterns on a workload of compiled microbenchmarks and application kernels. We find the vector cores provide greater efficiency than the MIMD cores, even on fairly irregular kernels. Our results suggest that the Maven VT microarchitecture is superior to the traditional vector-SIMD architecture, providing both greater efficiency and easier programmability.
The Structural Role of Lanthanum and Yttrium in Aluminosilicate Glasses: A 27Al and 17O MAS NMR Study

Aluminosilicate glasses containing rare-earth and rare-earth analogue cations such as Y3+ and La3+ are interesting for a variety of technological applications, as well as for elucidating general principles of glass formation and structure. We present high-resolution 17O and 27Al NMR data on a series of lanthanum and yttrium aluminosilicates, which show the significant increase in concentrations of AlO5 and AlO6 groups caused by the smaller radii and higher field strengths of the modifier cation in the latter. Triple-quantum magic-angle spinning (3QMAS) spectra for both nuclides show much better resolution than standard MAS and demonstrate that the latter can give misleading results for compositional effects on speciation. Oxygen sites that resemble those in crystalline Y2O3 and La2O3 were not detected, suggesting that such extreme clustering is not significant in the compositions studied. The role of highly coordinated Al, and the configurational complexity generated by the formation of such species, is d...
The Planetary Nebula Luminosity Function of M87 and the Intracluster Stars of Virgo

We present the results of a wide-field [O III] λ5007 survey for planetary nebulae (PN) in M87 and its surrounding halo. In all, we identify 338 PN candidates in a 16' × 16' field around the galaxy; 187 of these objects are in a statistical sample that extends to m5007 = 27.15. We show that the planetary nebula luminosity function (PNLF) of M87's halo is unlike any PNLF observed to date, with a shape that differs from that of the empirical law at the 99.9% confidence level. In addition, we find that the PNLF of M87's outer halo differs from that of the galaxy's inner regions at a high degree of certainty (~92%). We show that both these effects are most likely due to the existence of intracluster PN, many of which are foreground to M87. These intracluster objects explain the "overluminous" [O III] λ5007 sources previously identified by Jacoby, Ciardullo, & Ford and present us with a new tool with which to probe the morphological and dynamical properties of the cluster. By modifying the maximum likelihood procedures of Ciardullo et al. to take into account the presence of "field objects" and using an assumed M31 distance of 770 Kpc (Freedman & Madore) with a Burstein & Heiles reddening law, we derive a distance modulus to M87 of 30.79 ± 0.16 (14.4 ± 1.1 Mpc). This value is in excellent agreement with the previous survey of Jacoby, Ciardullo, & Ford and contradicts the assertion of Bottinelli et al. and Tammann that the PNLF distance to Virgo has been underestimated as a result of inadequate survey depth.
Motives of unitary and orthogonal homogeneous varieties

Abstract Grothendieck–Chow motives of quadric hypersurfaces have provided many insights into the theory of quadratic forms. Subsequently, the landscape of motives of more general projective homogeneous varieties has begun to emerge. In particular, there have been many results which relate the motive of a one homogeneous variety to motives of other simpler or smaller ones (see for example [N.A. Karpenko, Cohomology of relative cellular spaces and of isotropic flag varieties, Algebra i Analiz 12 (1) (2000) 3–69. [Kar00a] ; V. Chernousov, S. Gille, A. Merkurjev, Motivic decomposition of isotropic projective homogeneous varieties, Duke Math. J. 126 (1) (2005) 137–159. [CGM05] ; P. Brosnan, On motivic decompositions arising from the method of Bialynicki-Birula, Invent. Math. 161 (1) (2005) 91–111. [Bro05] ; S. Nikolenko, N. Semenov, K. Zainoulline, Motivic decomposition of anisotropic varieties of type F 4 into generalized Rost motives, preprint, Max-Planck-Institut fur Mathematik, 90, 2005. [NSZ05] ; K.V. Zaĭnullin, N.S. Semenov, On the classification of projective homogeneous varieties up to motivic isomorphism, Zap. Nauchn. Sem. S.-Peterburg. Otdel. Mat. Inst. Steklov. (POMI) 330 (2006) 158–172, 273. [ZS06] ; B. Calmes, V. Petrov, N. Semenov, K. Zainoulline, Chow motives of twisted flag varieties, Compos. Math. 142 (4) (2006) 1063–1080. [CPSZ06] ; K. Zainoulline, Motivic decomposition of a generalized Severi–Brauer variety, arXiv: math.AG/0601666 . [Zai] ]). In this paper, we exhibit a relationship between motives of two homogeneous varieties by producing a natural rational map between them. As an application, we compute the Chow group of zero-dimensional cycles on a homogeneous variety associated to a Hermitian form.
Observations of Massive Star-Forming Regions with Water Masers: Mid-Infrared Imaging

We present here a mid-infrared imaging survey of 26 sites of water maser emission. Observations were obtained at the Infrared Telescope Facility 3 m telescope with the University of Florida mid-infrared imager/spectrometer OSCIR, and the JPL mid-infrared camera MIRLIN. The main purpose of the survey was to explore the relationship between water masers and the massive star formation process. It is generally believed that water masers predominantly trace outflows and embedded massive stellar objects, but may also exist in circumstellar disks around young stars. We investigate each of these possibilities in light of our mid-infrared imaging. We find that mid-infrared emission seems to be more closely associated with water and OH maser emission than cm radio continuum emission from UC H II regions. We also find from the sample of sources in our survey that, like groups of methanol masers, both water and OH masers have a proclivity for grouping into linear or elongated distributions. We conclude that the vast majority of linearly distributed masers are not tracing circumstellar disks, but outflows and shocks instead.
Computational mechanics of cellular automata: an example

Abstract We illustrate and extend the techniques of computational mechanics in explicating the structures that emerge in the space-time behavior of elementary one-dimensional cellular automaton rule 54. The dominant regular domain of the cellular automation is identified and a domain filter is constructed to locate and classify defects in the domain. The primary particles are identified and a range of interparticle interactions is studied. The deterministic equation of motion of the filtered space-time behavior is derived. Filters of increasing sophistication are constructed for the efficient gathering of particle statistics and for the identification of higher-level defects, particle interactions, and secondary domains. We define the emergence time at which the space-time behavior condenses into configurations consisting only of domains, particles, and particle interactions. Taken together, these techniques serve as the basis for the investigation of pattern evolution and self-organization in this representative system.
Strong monotonicity in surplus sharing

We consider three new axioms for surplus sharing problems. The first is strong monotonicity which says that workers should be rewarded for increases in productivity and the second says that productive workers should receive some compensation. The third requires that the surplus sharing rule should be well defined (and continuous on) the set of threshold functions. We show that none of the standard "equitable" mechanisms satisfy any of these axioms and then present a constructive characterization of mechanisms which do. Using this we construct several new mechanisms. These are the Almost Flat mechanism, the Spread Aumann-Shapley mechanism, and the Spread Serial mechanism, which have many desirable properties.
The causes of recurrent geomagnetic storms

Interplanetary field and plasma data from earth-orbiting spacecraft during the period November 1973 to February 1974 were employed in analyzing the causes of recurrent geomagnetic activity. Two long sequences of geomagnetic activity and two corresponding corotating interplanetary streams figured in the data. The geomagnetic activity is discussed in terms of the electric field produced by the ordered mesoscale pattern of the stream itself, and by random smaller-scale fluctuations in the southward component of the interplanetary magnetic field.
Sound‐speed profile inversion in the ocean

For sound speed profiles which vary only in depth, a method has been developed whereby the scattered field data in frequency (or k-space) can be related to the sound speed profile correction (from an assumed profile guess input) as a quasi-Fourier transform pair. The inversion is straightforward. The method uses a Fourier-Bessel representation of the acoustic field, a Born approximation on the depth dependent part of the Green’s function, a WKB representation for the wave functions and asymptotics and linearization to derive the transform pair. Small perturbations about the main profile trend are recovered very accurately if the background slope is assumed known.
An adaptive packed-memory array

The packed-memory array (PMA) is a data structure that maintains a dynamic set of N elements in sorted order in a Θ(N)-sized array. The idea is to intersperse Θ(N) empty spaces or gaps among the elements so that only a small number of elements need to be shifted around on an insert or delete. Because the elements are stored physically in sorted order in memory or on disk, the PMA can be used to support extremely efficient range queries. Specifically, the cost to scan L consecutive elements is O(1 p LsB) memory transfers.This article gives the first adaptive packed-memory array (APMA), which automatically adjusts to the input pattern. Like the traditional PMA, any pattern of updates costs only O(log2N) amortized element moves and O(1 p (log2N)sB) amortized memory transfers per update. However, the APMA performs even better on many common input distributions achieving only O(log N) amortized element moves and O(1p (logN)sB) amortized memory transfers. The article analyzes sequential inserts, where the insertions are to the front of the APMA, hammer inserts, where the insertions “hammer” on one part of the APMA, random inserts, where the insertions are after random elements in the APMA, and bulk inserts, where for constant α e [0, 1], Nα elements are inserted after random elements in the APMA. The article then gives simulation results that are consistent with the asymptotic bounds. For sequential insertions of roughly 1.4 million elements, the APMA has four times fewer element moves per insertion than the traditional PMA and running times that are more than seven times faster.
No Pain, No Gain: Hard Probes of the Quark-Gluon Plasma Coming of Age

Abstract This lecture presents a concise review of the current status of hard QCD and electromagnetic processes as probes of the quark–gluon plasma.
Mild Addition of Nucleophiles to Pyridine-N-Oxides

A general and facile one-pot procedure for the synthesis of 2-substituted pyridines from the corresponding pyridine-N-oxides and nucleophiles is presented as a mild alternative to SNAr chemistry. A variety of nucleophiles and heterocyclic-N-oxides participate effectively in this transformation, which uses the phosphonium salt, PyBroP, as a means of substrate activation.
Dual-function cinchona alkaloid catalysis: catalytic asymmetric tandem conjugate addition-protonation for the direct creation of nonadjacent stereocenters.

Catalytic tandem asymmetric reactions constitute a powerful strategy for the asymmetric construction of nonadjacent stereocenters in acyclic molecules directly from achiral precursors. In this Communication, we report a highly enantioselective and diastereoselective addition of trisubstituted carbon donors to 2-chloroacrylonitrile catalyzed by bifunctional cinchona alkaloid catalysts. This represents the first asymmetric tandem conjugate addition−protonation with efficient catalytic control of two nonadjacent stereocenters. As demonstrated in a concise and highly stereoselective formal total synthesis of (−)-manzacidin A, this asymmetric tandem reaction establishes a new and versatile catalytic approach for the enantioselective and diastereoselective creation of 1,3-tertiary−quaternary stereocenters.
Extratropical Rossby Waves in the Presence of Buoyancy Mixing

Abstract The propagation of Rossby waves on a midlatitude β plane is investigated in the presence of density diffusion with the aid of linear hydrostatic theory. The search for wave solutions in a vertically bounded medium subject to horizontal (vertical) diffusion leads to an eigenvalue problem of second (fourth) order. Exact solutions of the problem are obtained for uniform background stratification (N), and approximate solutions are constructed for variable N using the Wentzel–Kramers–Brillouin method. Roots of the eigenvalue relations for free waves are found and discussed. The barotropic wave of adiabatic theory is also a solution of the eigenvalue problem as this is augmented with density diffusion in the horizontal or vertical direction. The barotropic wave is undamped as fluid parcels in the wave move only horizontally and are therefore insensitive to the vortex stretching induced by mixing. On the other hand, density diffusion modifies the properties of baroclinic waves of adiabatic theory. In th...
Rationality, integrity, and religious behavior

Abstract Borrowing insights from philosophical discussions on the concept of integrity, we propose a framework to understand religious behavior in consumption, production, and exchange. Whereas previous economic explanations of religious behavior have focused on preferences, opportunity sets, or social pressure, we emphasize the notion of integrity defined as identity-conferring commitments. We provide a framework that not only introduces commitment and identity but includes previous explanations as special cases. We also discuss extensions of the framework in addressing the multiplicity of the dimensions of identity.
Non-constant parameter NC tool path generation on sculptured surfaces

An algorithm for three-axis NC tool path generation on sculptured surfaces is presented. Non-constant parameter tool contact curves are defined on the part by intersecting parallel planes with the part model surface. Four essential elements of this algorithm are introduced: initial chordal approximation, true machining error calculation, direct gouge elimination, and non-constant parameter tool pass interval adjustment. A software implementation of this algorithm produces graphical output depicting the tool path superimposed over the part surface, and it outputs cutter location (CL) data for further post-processing. Several applications examples are presented to demonstrate the capabilities of the algorithm. The results of this technique are compared to those generated from a commercially available computer-aided manufacturing program, and indicate that equivalent accuracy is obtained with many fewer CL points.
A Sub-nW 2.4 GHz Transmitter for Low Data-Rate Sensing Applications

This paper presents the design of a narrowband transmitter and antenna system that achieves an average power consumption of 78 pW when operating at a duty-cycled data rate of 1 bps. Fabricated in a 0.18 µm CMOS process, the transmitter employs a direct-RF power oscillator topology where a loop antenna acts as a both a radiative and resonant element. The low-complexity single-stage architecture, in combination with aggressive power gating techniques and sizing optimizations, limited the standby power of the transmitter to only 39.7 pW at 0.8 V. Supporting both OOK and FSK modulations at 2.4 GHz, the transmitter consumed as low as 38 pJ/bit at an active-mode data rate of 5 Mbps. The loop antenna and integrated diodes were also used as part of a wireless power transfer receiver in order to kick-start the system power supply during energy harvesting operation.
Robustness Characteristics of Optimum Structural/Control Design

An optimization program has been developed to design a minimum-weight flexible structure with constraints imposed on the closed-loop damping parameters, eigenvalue distribution, and the robustness bounds of the control system to retain stability under structured uncertainties. The formulation of approximate analytical expressions for the derivatives of the robustness measure is presented. The optimization problem was solved by using a nonlinear mathematical optimization technique. The numerical results are presented for the Draper 1 tetrahedral truss structure to satisfy different design requirements. These results indicate that the constraints on the damping parameters have to be imposed in addition to the robustness measure in order to improve the dynamic response. HE traditional approach to the design of a structure and control system has been sequential. The structure is first designed to satisfy the constraints on the allowable stresses, displacements, frequencies, etc., and then the control system is designed on this fixed structure. The control design has to satisfy its design requirements such as performance, control effort, robustness, stability, etc. This sequential approach generally does not lead to an optimum performance of the structure and control system for a specific mission. The opti- mum structural design and optimum control design have de- veloped into mature fields. However, because of the stringent requirements in the design of future aerospace structures, there is currently considerable interest in developing al- gorithms for the simultaneous design of the structure and control system. The mathematical model representing a physical system in- evitably contains inaccuracies. This would compromise the performance of the control system, making the system un- stable if one does not allow for these modeling errors. The modeling uncertainties are generally divided into two broad categories. The first is the parametric or structured uncertain- ties that result due to the variations in the real and analytical frequencies of the structure. The second is due to the unmod- eled higher frequencies. The robust-control system is designed to maintain closed-loop stability and performance in the pres- ence of unknown or known structured and unstructured un- certainties. The order of the finite element model of a space structure is generally too high and this necessitates the use of a reduced-order model constructed by truncating the higher vibration modes to design a controller. This reduction in the dimensionality of the controller sometimes leads to the spill- over effect when it is used on a higher order structural model. There have been various approaches proposed by different investigators in order to reduce or prevent the spillover effect. The objective of this paper was to develop an optimization algorithm to design a structure and control system by taking into consideration a robustness parameter that defines the structural uncertainties in a closed-loop system. The linear quadratic regulator (LQR) with a full-order controller is used
Matching polytopes and Specht modules

We prove that the dimension of the Specht module of a forest $G$ is the same as the normalized volume of the matching polytope of $G$. We also associate to $G$ a symmetric function $s_G$ (analogous to the Schur symmetric function $s_\lambda$ for a partition $\lambda$) and investigate its combinatorial and representation-theoretic properties in relation to the Specht module and Schur module of $G$. We then use this to define notions of standard and semistandard tableaux for forests.
Cosmological implications of low energy supersymmetry breaking models

Abstract We show that stable local cosmic strings are a generic prediction of supersymmetric models where supersymmetry is broken at scales within a few orders of magnitude of the weak scale and is fed down to the observable sector by gauge interactions. The typical energy scale of these strings is about 102 TeV. Since in the most general and natural scenario there are two different sources of contributions to ordinary superpartner masses, gauge mediation from the messanger sector and anomalous U(1)D-terms, novel features are that the cosmic strings may be superconducting with the role of bosonic charge carriers played by squarks and sleptons and that some baryonic or leptonic charge may be stored in the core of the string. Possible cosmological and astrophysical implications of these superconducting strings are discussed.
Commutation signaling&#8212;An antimultipath technique

Two types of commutation signaling for combating multipath are introduced: M × N signaling, in which the signal set cycles successively among N different sets of M signals each; and M + N signaling, in which the signal set at any time consists of M members of an alphabet of M + N signals, N of which are inactive at any epoch. In both cases, the objective is to remove from use any signal sent recently enough that it is still "ringing" in the multipath channel. We consider the problems of minimization of M and N, hence the total number signals used; analysis of 2 × N sets (M = 2 is almost uniformly optimal); analysis of the simplest M + N set, i.e., a 2 + 1 set; and presentation of the results of simulation of M × N and M + N signaling through realistic urban/suburban radio channels. Comparison of these simulations to simulations of other antimultipath techniques is also made. The simulation results are due to Kamil [3].
Ultra-high-Energy Cosmic-Ray Sources and Large-Scale Magnetic Fields

Protons of energies up to about 1020 eV can be subject to significant deflection and energy-dependent time delay in large-scale extragalactic or halo magnetic fields of strengths comparable to current upper limits. By performing three-dimensional Monte Carlo simulations of nucleon propagation, we show how observations of arrival direction and time distributions can be used to measure the structure and strength of large-scale magnetic fields and constrain the nature of the source of ultra-high-energy cosmic rays.
The identification of monetary policy disturbances Explaining the liquidity puzzle

Abstract This paper examines recent work on the identification of monetary policy disturbances. Its main finding is that the empirical anomalies found in the literature reflect a failure to properly address the Federal Reserve's policy of accommodating reserve demand shocks. A new method of identifying monetary policy using nonborrowed reserves is proposed. Using this specification — policy has a strong persistent liquidity effect regardless of subsample — policy Granger-causes output even in the presence of interest rates, explaining approximately 49% of the variance in output at a two-year horizon — and the residual explanatory power of interest rates for output is negligible.
KPP pulsating front speed-up by flows

We obtain a criterion for pulsating front speed-up by general periodic incompressible flows in two dimensions and in the presence of KPP nonlinearities. We achieve this by showing that the ratio of the minimal front speed and the effective diffusivity of the flow is bounded away from zero and infinity by constants independent of the flow. We also study speed-up of reaction-diffusion fronts by various examples of flows in two and three dimensions.
Astrophysical Uncertainties in the Cosmic Ray Electron and Positron Spectrum From Annihilating Dark Matter

In recent years, a number of experiments have been conducted with the goal of studying cosmic rays at GeV to TeV energies. This is a particularly interesting regime from the perspective of indirect dark matter detection. To draw reliable conclusions regarding dark matter from cosmic ray measurements, however, it is important to first understand the propagation of cosmic rays through the magnetic and radiation fields of the Milky Way. In this paper, we constrain the characteristics of the cosmic ray electron/positron propagation model through comparison with observational inputs, including recent data from the CREAM experiment, and use these constraints to estimate the corresponding uncertainties in the spectrum of cosmic ray electrons and positrons from dark matter particles annihilating in the halo of the Milky Way.
Collision-Induced Infrared Absorption by Molecular Hydrogen Pairs at Thousands of Kelvin

Collision-induced absorption by hydrogen and helium in the stellar atmospheres of cool white dwarfs causes the emission spectra to differ significantly from the expected blackbody spectra of the cores. For detailed modeling of radiative processes at temperatures up to 7000 K, the existing H2–H2 induced dipole and potential energy surfaces of high quality must be supplemented by calculations with the H2 bonds stretched or compressed far from the equilibrium length. In this work, we describe new dipole and energy surfaces, based on more than 20 000 ab initio calculations for H2–H2. Our results agree well with previous ab initio work (where those data exist); the calculated rototranslational absorption spectrum at 297.5 K matches experiment similarly well. We further report the calculated absorption spectra of H2–H2 for frequencies from the far infrared to 20 000 cm−1, at temperatures of 600 K, 1000 K, and 2000 K, for which there are no experimental data.
Amniotic fluid embolism: the known and not known:

Amniotic fluid embolism was first recognized in 1926, in a Brazilian journal case report, on the basis of large amounts of fetal material in the maternal pulmonary vasculature at autopsy. The first English language description appeared in 1941 and consisted of eight parturients dying suddenly in which, once again, fetal material was seen in the pulmonary vasculature. A control group of 34 pregnant women dying of other recognized causes did not have fetal material in their lungs. The incidence of recognized, serious illness is on the order of two to eight per 100,000, with a mortality rate ranging from 13% to 35%. The diagnosis rests largely on one or more of four clinical signs: circulatory collapse, respiratory distress, coagulopathy, and seizures/ coma. The only confirmatory laboratory test remains autopsy findings although serum tests for fetal antigen, insulin-like growth factor binding protein-1, and complement are currently being investigated. One of the paradoxes of diagnosis is that fetal material in the pulmonary circulation at autopsy is specific for amniotic fluid embolism, while the same finding in the living is not. The mechanism of disease remains uncertain although the best available evidence suggests that complement activation might have a role. In contrast, mast cell degranulation probably is not a mechanism, so amniotic fluid embolism is not an anaphylaxis or anaphylactoid reaction as has been occasionally suggested. Perhaps the greatest unknown is not why 1 in 50,000 pregnant women develop what appears to be an immune response to their fetus, but rather why the other 49,999 do not?
Concentration of measures via size-biased couplings

Let Y be a nonnegative random variable with mean μ and finite positive variance σ2, and let Ys, defined on the same space as Y, have the Y size-biased distribution, characterized by $$ E[Yf(Y)]=\mu E f(Y^s) \quad {\rm for\,all\,functions}\,f\,{\rm for\,which\,these\,expectations\,exist}. $$ Under a variety of conditions on Y and the coupling of Y and Ys, including combinations of boundedness and monotonicity, one sided concentration of measure inequalities such as $$ P\left(\frac{Y-\mu}{\sigma} \ge t\right)\le {\rm exp}\left(-\frac{t^2}{2(A+Bt)} \right) \quad {\rm for\,all}\,t\, > 0 $$ hold for some explicit A and B. The theorem is applied to the number of bulbs switched on at the terminal time in the so called lightbulb process of Rao et al. (Sankhyā 69:137–161, 2007).
Weakly first order cosmological phase transitions and fermion production

Abstract We study weakly first order cosmological phase transitions in finite temperature field theories. Focusing on the standard electroweak theory and its minimal supersymmetric extension, we identify the regimes of Higgs masses for which the phase transition in these models proceeds by significant phase mixing and the coarsening of the subsequent domain network. This dynamics is distinct from that for strongly first order transitions, which proceed by the nucleation and propagation of critical bubbles. We describe how electroweak baryogenesis might take place in these models, explaining how our new picture can relax the sphaleron washout bound of traditional scenarios.
Estimation of copula-based semiparametric time series models

This paper studies the estimation of a class of copula-based semiparametric stationary Markov models. These models are characterized by nonparametric marginal distributions and parametric copula functions, while the copulas capture all the scale-free temporal dependence of the processes. Simple estimators of the marginal distribution and the copula parameter are provided, and their asymptotic properties are established under easily verifiable conditions. These results are used to obtain root-n consistent and asymptotically normal estimators of important features of the transition distribution such as the (nonlinear) conditional moments and conditional quantiles. The semiparametric conditional quantile estimators are automatically monotonic across quantiles, which is attractive for portfolio conditional value-at-risk calculations.
Data-management and analysis systems for large-scale hydrogeochemical reconnaissance

Abstract The Savannah River Laboratory has developed a versatile, computerized data recording, processing, updating, and retrieval system for handling an expected 150 million bytes of hydrogeochemical data from 150,000 to 200,000 sample sites through the next four years. A subsystem accounts for the movements of samples from initial receipt through final storage. Approximately 6 million sample movements are expected. Two- and three-dimensional plots of sampled geographic areas showing concentrations and locations of individual chemical elements are displayed and reproduced photographically. Pattern recognition techniques enable multivariate data to be categorized into ‘clusters’ which indicate sites favorable for uranium exploration.
On large deviations theory and asymptotically efficient Monte Carlo estimation

It is shown how large-deviations theory can be applied to construct an asymptotically efficient simulation distribution for Monte Carlo simulation using the importance sampling technique. A sufficient and necessary condition is given for the asymptotic efficiency of the candidate simulation distributions. This is done in the multidimensional setting that is required by many practical simulation problems. The result obtained is applied primarily in two areas. First, the generalization of previous work dealing with functionals of Markov chains is discussed. A second area of application is the simulation of nonlinear systems with Gaussian inputs. As an example of a system with Gaussian inputs, the simulation of a digital communication channel with nonlinear ISI (intersymbol interference) characteristic of satellite data links is considered. In the case of linear ISI, the asymptotically efficient exponentially twisted distribution turns out to agree with a method previously proposed by D. Lu and K. Yao (1988). The large-deviations point of view provides some useful insight on how to extent the Lu and Yao method to nonlinear channels. >
International Financial Volatility and Commodity Exports: Evidence from the Thai Agricultural Sector

Using 1981--2006 data from the Bank of Thailand, I estimate the effect of four measures of real exchange rate volatility on Thai exports of five key agricultural commodities, controlling for both the level of the real exchange rate and foreign incomes. Estimates of the effect of volatility on export volume are generally negative and often significant, lending support to a range of theoretical models that predict such an effect. No such relationship exists between lagged values of exchange rate volatility and agricultural production. The range of results obtained using various measures of volatility suggests caution in comparing studies using different measures. Copyright 2010, Oxford University Press.
Improved Seasonal Climate Forecasts of the South Asian Summer Monsoon Using a Suite of 13 Coupled Ocean–Atmosphere Models

Abstract Several modeling studies have shown that the south Asian monsoon region has the lowest skill for seasonal forecasts compared with many other domains of the world. This paper demonstrates that a multimodel synthetic superensemble approach, when constructed with any set of coupled atmosphere–ocean models, can provide improved skill in seasonal climate prediction compared with single-member models or their ensemble mean for the south Asian summer monsoon region. However, performance of the superensemble tends to improve when a better set of input member models are used. As many as 13 state-of-the-art coupled atmosphere–ocean models were used in the synthetic superensemble algorithm. The merit of this technique lies in assigning differential weights to the member models. The rms errors, anomaly correlations, case studies of extreme events, and probabilistic skill scores are used here to assess these forecast skills. It was found that over the south Asian region the seasonal forecasts from the superen...
The ultraviolet peak of the energy distribution in 3c 273: evidence for an accretion disk and hot corona around a massive black hole

We present absolutely calibrated far-ultraviolet spectrophotometry of the quasar 3C 273 covering the 900-1800 A range. Our ~3 A resolution spectra were obtained with the Hopkins Ultraviolet Telescope (HUT) during the Astro-1 mission in 1990 December and during the Astro-2 mission in 1995 March. Both spectra exhibit a change in slope near the Lyman limit in the quasar rest frame. At longer UV wavelengths, the continuum has a power-law index of 0.5-0.7, while shortward of the Lyman limit it is 1.2-1.7. The energy distribution in νfν, therefore, peaks close to the quasar Lyman limit. The short-wavelength UV power law extrapolates well to match the soft X-ray excess seen in simultaneous observations with the Broad Band X-Ray Telescope (BBXRT) and nearly simultaneous ROSAT observations. The general shape of the broadband spectrum of 3C 273 is consistent with that of an optically thick accretion disk whose emergent spectrum has been Comptonized by a hot medium. Our UV spectrum is well described by a Schwarzschild black hole of 7 × 108 M☉ accreting matter at a rate of 13 M☉ yr-1 through a disk inclined at 60°. Superposed on the intrinsic disk spectrum is an empirically determined Lyman edge of optical depth 0.5. The Comptonizing medium has a Compton parameter y ≈ 1, obtained with an optical depth to electron scattering of unity and a temperature of 4 × 108 K. This overall shape is the same as that found by Zheng et al. and Laor et al. in their UV and X-ray composite spectra for quasars, giving physical validity to the composite spectrum approach. When combined with those results, we find that the generic ionizing continuum shape for quasars is a power law of energy index 1.7-2.2, extending from the Lyman limit to ~1 keV. The observational gap in the extreme ultraviolet for these combined data describing the quasar continuum shape is now only half a decade in frequency.