cssi/SciSciGPT-SciSciNet huggingface dataset:
A numerical method for the design and analysis of counter-rotating propellers

A numerical method has been developed using the techniques of Lock and Theodorsen as described by Davidson to design and analyze counter-rotating propellers. The design method develops the optimum propeller geometry by calculating the planform and twist distribution for each propeller disk through the use of specific inputs of engine shaft horsepower, diameter, and disk spacing. The analysis method calculates the performance of a given counter-rotating propeller system at any flight condition. Using the NACA four-digit airfoil family, the performance of a counter-rotating propeller design for a given flight condition was investigated in the design and analysis mode.
Impact of LHC searches on NLSP top squark and gluino mass

We explore the implications of 7 TeV LHC searches for a scenario in which one of the stops is the next-to-lightest supersymmetric particle (NLSP). The NLSP stop $ \left( {{{\tilde{t}}_1}} \right) $ is assumed to decay exclusively into neutralino and charm quark. We consider processes where the stops are pair produced together with a hard QCD jet. We also consider stop quarks from gluino decays, $ \tilde{g} \to t\tilde{t}_1^{ * } + \bar{t}{\tilde{t}_1} $ . We show that the monojet ATLAS and CMS searches corresponding to 1 fb−1 of integrated luminosity are sensitive to stop masses of up to 160 GeV, with the 20 % neutralino-stop coannihilation region essentially ruled out for $ {M_{{{{\tilde{t}}_1}}}}{\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle\thicksim}$}}{ < }}140\,{\text{GeV}} $ . The region $ {M_{{{{\tilde{t}}_1}}}}{\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle\thicksim}$}}{ < }}130\,{\text{GeV}} $ is excluded with even relatively larger mass difference, $ {M_{{{{\tilde{t}}_1}}}} - {M_{{\tilde{\chi }_1^0}}} \sim 40\,{\text{GeV}} $ , by the multi-jets search. The b-jet and same-sign dilepton searches are sensitive to a heavier gluino because they only pick up gluino pair production events followed by top quarks decaying into b-jets and same-sign dileptons, respectively. We find that the LHC data places a lower limit on the gluino mass in this scenario of about 600 GeV (700 GeV) from b-jets (same-sign dileptons) searches.
Abnormal sperm morphology is highly predictive of pregnancy outcome during controlled ovarian hyperstimulation and intrauterine insemination.

Purpose: The purpose of this study was to assess the predictive value of a modified form of Kruger's strict criteria for sperm morphology for pregnancy outcomes after intrauterine insemination (IUI) and controlled ovarian hyperstimulation (COH) in the presence of normal sperm concentration and motility.
Simultaneous Transmission and Reception: Algorithm, Design and System Level Performance

Full Duplex or Simultaneous transmission and reception (STR) in the same frequency at the same time can potentially double the physical layer capacity. However, high power transmit signal will appear at receive chain as echoes with powers much higher than the desired received signal. Therefore, in order to achieve the potential gain, it is imperative to cancel these echoes. As these high power echoes can saturate low noise amplifier (LNA) and also digital domain echo cancellation requires unrealistically high resolution analog-to-digital converter (ADC), the echoes should be cancelled or suppressed sufficiently before LNA. In this paper we present a closed-loop echo cancellation technique which can be implemented purely in analogue domain. The advantages of our method are multiple-fold: it is robust to phase noise, does not require additional set of antennas, can be applied to wideband signals and the performance is irrelevant to radio frequency (RF) impairments in transmit chain. Next, we study a few protocols for STR systems in carrier sense multiple access (CSMA) network and investigate MAC level throughput with realistic assumptions in both single cell and multiple cells. We show that STR can reduce hidden node problem in CSMA network and produce gains of up to 279% in maximum throughput in such networks. Moreover, at high traffic load, the gain of STR system can be tremendously large since the throughput of non-STR system is close to zero at heavy traffic due to severe collisions. Finally, we investigate the application of STR in cellular systems and study two new unique interferences introduced to the system due to STR, namely BS-BS interference and UE-UE interference. We show that these two new interferences will hugely degrade system performance if not treated appropriately. We propose novel methods to reduce both interferences and investigate the performances in system level. We show that BS-BS interference can be suppressed sufficiently enough to be less than thermal noise power, and with favorable UE-UE channel model, capacities close to double are observed both in downlink (DL) and uplink (UL). When UE-UE interference is larger than DL co-channel interferences, we propose a simple and "non-cooperative" technique in order to reduce UE-UE interference.
General-interest versus specialty journals: Using intellectual influence of econometrics research to rank economics journals and articles

This paper demonstrates the potential problem in using existing economics journal rankings to evaluate the research productivity of scholars by constructing a new ranking of economics journals and articles. Based on 2142 econometrics sample articles published from 2000 to 2005, our ranking results show that the intellectual influence of an econometrics article published in several econometrics/statistics journals is much higher than if it were published in the most prestigious general-interest journal. Given that a study's potential influence is integrated into the submission decision, this suggests a substantial downward bias toward econometricians when existing rankings are used to evaluate their research productivity. Copyright © 2009 John Wiley & Sons, Ltd.
Voids and pits on sputter-annealed fivefold terraces of icosahedral Al–Pd–Mn quasicrystals

Our scanning tunneling microscope studies on clean surfaces of fivefold icosahedral Al70.2Pd20.7Mn9.1 reveal that, after annealing at 900 K, two types of flat depressions are visible on terraces: voids (small, shallow, flat-bottomed depressions bordered by 2.5 A steps) and pits (deeper, and often larger, depressions). They are different not only in their dimensions but in their behavior: voids preferentially nucleate on some of the terraces and, after annealing at 925 K, their coalescence and growth leads a new type of termination to be exposed. Pits, however, do not destroy the terraces on which they exist, under the experimental conditions. At the bottom of 4.1 A-deep pits, 2.5 A-deep voids nucleate, so that the total depth of the pit is 6.6 A. We propose that 2.5 A void-rich terraces are metastable terminations, and that these metastable terminations are also exposed at the bottom of the 4.1 A-deep pits.
Plasmo-photonic nanowire arrays for large-area surface-enhanced Raman scattering sensors

The remarkably high electromagnetic fields that can be induced by the optical stimulation of surface plasmons in plasmonic nanostructures can induce large enhancements to Raman scattering. The Surface-enhanced Raman Scattering (SERS) effect offers great potential for the development of molecular sensors with low false alarm rates and high sensitivity. Although research in this field has grown at a very fast pace in recent years, most of this work has focused on attaining the highest enhancements at highly localized hot-spots, which while providing large peak enhancements, exhibit very low average enhancement factors, making their use for most sensing applications unlikely. Here we report on Au-coated Si nanopillar arrays where we probe the dependence of the SERS enhancement on both the nanopillar diameter and the interpillar gap over a range extending from 30 to 245 nm and 20 to 165 nm, respectively. This approach allows for the optimization of the SPR condition relative to the incident laser wavelength chosen, enabling an optimized SERS sensor. As the interparticle gaps approach 20 nm, we also explored arrays of nanopillars where interparticle plasmonic coupling should exist, however, it remains unclear if any such collective effects are present. The arrays created do illustrate very large highly uniform (<30% deviation) SERS enhancement factors (G), with G in excess of 1x10 7 being reported. In addition, we explored the role of the nanoparticle geometry, where we determined that a higher G is observed for circle in comparison to square nanopillars of similar dimensions. The SERS enhancement was found to have a very distinct dependence on the nanopillar diameter, while only a monotonic increase was observed with increasing interpillar gap. These results suggest great suitability of plasmo-photonic large-area nanopillar arrays for SERS vapor and liquid sensor applications.
Synthesis, physicochemical characterization and crystallographic twinning of Li2ZnSnS4

Abstract Li2ZnSnS4 is a new diamond-like semiconductor, which is of interest as a host structure for the creation of potentially interesting electronic, magnetic and photovoltaic materials. The compound was synthesized via traditional high-temperature solid-state methods and was predicted to adopt a wurtz-stannite structure with all atoms possessing tetrahedral environments. Initial analysis of single-crystal X-ray diffraction data indicated crystallographic disorder that upon closer examination violated basic chemical principles. The structure was subsequently re-evaluated and the apparent “disorder” problem was found to be the result of pseudo-merohedral twinning. The crystal structure was finally solved in the monoclinic space group Pn, which resulted in a chemically reasonable model. The refinement converged with R1=1.68% (for all data). Additional characterization of the sample, including diffuse reflectance, thermal analysis and second harmonic generation measurements, was also performed.
Trace formula for a system of particles with elliptic potential

We consider classical particles on the line with the Weierstrass } function as potential. This system parameterizes special solutions of the KP equation. We derive the trace formula which relates the Hamiltonian of the par- ticle system to the residues of some Abelian differential (meromorphic one-form) on the spectral curve. Such formula is important for the construction action-angle variables and study invariant Gibbs' states.
Smooth and Starburst Tidal Tails in the GEMS and GOODS Fields

GEMS and GOODS fields were examined to z ~ 1.4 for galaxy interactions and mergers. The basic morphologies are familiar: antennae with long tidal tails, tidal dwarfs, and merged cores; M51-type galaxies with disk spirals and tidal arm companions; early-type galaxies with diffuse plumes; equal-mass grazing collisions; and thick J-shaped tails beaded with star formation and double cores. One type is not common locally and is apparently a loose assemblage of smaller galaxies. Photometric measurements were made of the tails and clumps, and physical sizes were determined assuming photometric redshifts. Antennae tails are a factor of ~3 smaller in GEMS and GOODS systems compared to local antennae; their disks are a factor of ~2 smaller than locally. Collisions among early type galaxies generally show no fine structure in their tails, indicating that stellar debris is usually not unstable. One exception has a 5 × 109 M☉ smooth red clump that could be a pure stellar condensation. Most tidal dwarfs are blue and probably form by gravitational instabilities in the gas. One tidal dwarf looks like it existed previously and was incorporated into the arm tip by tidal forces. The star-forming regions in tidal arms are 10-1000 times more massive than star complexes in local galaxies, although their separations are about the same. If they all form by gravitational instabilities, then the gaseous velocity dispersions in interacting galaxies have to be larger than in local galaxies by a factor of ~5 or more; the gas column densities have to be larger by the square of this factor.
Complexity of nilpotent orbits and the Kostant-Sekiguchi correspondence

Let G be a connected linear semisimple Lie group with Lie algebra Open image in new window, and let Open image in new window be the complexified isotropy representation at the identity coset of the corresponding symmetric space. Suppose that Ω is a nilpotent G-orbit in Open image in new window and Open image in new window is the nilpotent Open image in new window-orbit in Open image in new window associated to Ω by the Kostant-Sekiguchi correspondence. We show that the corank of the Hamiltonian K-space Ω is twice the complexity of the Open image in new window variety Open image in new window.
Band Edge Effects and Normal Mode Propagation in Waveguide Magnetophotonic Crystals

A study of band edge phenomena in ridge waveguide magnetophotonic crystals is presented. Normal mode analysis is used to examine the near-band edge and Bragg center-wavelength group velocities and their relation to the polarization. Large polarization departures from the input are observed in Bragg gratings patterned by focused-ion-beam milling on liquid-phase-epitaxial (LPE) (Bi,Lu)(2.8±0.1)Fe(4.6±0.2)O(12.4±0.3) films on (111) gadolinium gallium garnet (GGG) substrates. Transfer matrix analysis of the spectral response in the photonic crystals allows the determination of the phase of the elliptically polarized normal modes from measured transmittances and polarization rotation. Unlike non-birefringent Faraday rotators a non-linear-relation exists between polarization rotation and the normal mode phase difference. Large phase differences between right- and left-elliptically polarized normal modes and optical slow-down are found near the band edges and at the resonant cavity center-wavelength. Standing-wave photon trapping and optical slow-down are analyzed and compared for these systems.
Recoil saturation of the self-energy in atomic systems

We consider the dispersion-interaction self-energy of two atoms or of a charge and an atom without imposing the Born-Oppenheimer approximation. We find compact expressions in terms of matrix elements of operators in the atomic displacement which are not limited by multipole expansions. The saturation effect of recoil causes the self-energy to be finite even at small separation. The relation to previously obtained results in terms of multipole expansions is discussed.
The synthesis and evaluation of 12,13-benzodesoxyepothilone B: A highly convergent route

Abstract The title compound retains some of the affinity for microtubule assemblies as does 12,13-desoxyepothilone B.
Analysis of the GMAW Process for Microprocessor Control of Arc Length

Control of arc length is an essential component of the automation of arc welding processes. It is even more critical in gas metal arc welding where the arc length can vary substantially since it is closely tied to the melting process. Variations in arc length can greatly affect the quality of the weld produced. Even though there are currently systems available for controlling arc length, the theory necessary for microprocessor control is not fully developed. This paper develops a model of the gas metal arc welding process as a basis for arc length control, using the input to the wire feed drive motor as the control signal. The weld process is found to be first order after linearization, and that, coupled with the drive motor dynamics, produces a second-order system. The model is verified experimentally and is found to correlate very well with experimental results, the calculated time constant for the welding system in the constant current mode being 1.7 s, while the measured value is approximately 1.5 s.
Determining the actual local density of dark matter particles

Even if dark matter particles were unambiguously discovered in experiments, there is no clear reason to expect that this would resolve the dark matter problem. It is very easy to provide examples of dark matter scenarios (e.g. in supersymmetric models) in which nearly identical detector signals correspond to extremely different relic densities. The density of the discovered particles, therefore, must be determined before their cosmological relevance can be established. In this paper, I present a general method that utilizes both dark matter and hadron collider experimental data (once they become available) to estimate the local density of dark matter particles. These results were obtained in collaboration with Gordon Kane at the University of Michigan.
Fault-Tolerant Real-Time Scheduling

We use competitive analysis to study how best to use redundancy to achieve fault-tolerance in online real-time scheduling. We show that the optimal way to use spatial redundancy depends on a complex interaction of the benefits, execution times, release times, and latest start times of the jobs. We give a randomized online algorithm whose competitive ratio is O( logΦ log Delta ( log 2 n log m/ log log m)) for transient faults. Here n is the number of jobs, m is the number of processors, Φ is the ratio of the maximum value density of a job to the minimum value density of a job, and Δ is the ratio of the longest possible execution time to the shortest possible execution time. We show that this bound is close to optimal by giving an Ω(( log ΔΦ/ log log m) ( log m log log m) 2 ) lower bound on the competitive ratio of any randomized algorithm. In the case of permanent faults, there is a randomized online algorithm that has a competitive ratio of O( log Phi log Δ (log m/log log m)). We also show a lower bound of Ω((log ΔΦ/ log log m) ( log m/log log m)) on the competitive ratio for interval scheduling with permanent faults.
Two homologous intermetallic phases in the Na-Au-Zn system with sodium bound in unusual paired sites within 1D tunnels.

The Na-Au-Zn system contains the two intermetallic phases Na(0.97(4))Au(2)Zn(4) (I) and Na(0.72(4))Au(2)Zn(2) (II) that are commensurately and incommensurately modulated derivatives of K(0.37)Cd(2), respectively. Compound I crystallizes in tetragonal space group P4/mbm (No. 127), a = 7.986(1) A, c = 7.971(1) A, Z = 4, as a 1 × 1 × 3 superstructure derivative of K(0.37)Cd(2) (I4/mcm). Compound II is a weakly incommensurate derivative of K(0.37)Cd(2) with a modulation vector q = 0.189(1) along c. Its structure was solved in superspace group P4/mbm(00g)00ss, a = 7.8799(6) A, c = 2.7326(4) A, Z = 2, as well as its average structure in P4/mbm with the same lattice parameters.. The Au-Zn networks in both consist of layers of gold or zinc squares that are condensed antiprismatically along c ([Au(4/2)Zn(4)Zn(4)Au(4/2)] for I and [Au(4/2)Zn(4)Au(4/2)] for II) to define fairly uniform tunnels. The long-range cation dispositions in the tunnels are all clearly and rationally defined by electron density (Fourier) mapping. These show only close, somewhat diffuse, pairs of opposed, ≤50% occupied Na sites that are centered on (I) (shown) or between (II) the gold squares. Tight-binding electronic structure calculations via linear muffin-tin-orbital (LMTO) methods, assuming random occupancy of ≤ ∼100% of nonpaired Na sites, again show that the major Hamilton bonding populations in both compounds arise from the polar heteroatomic Au-Zn interactions. Clear Na-Au (and lesser Na-Zn) bonding is also evident in the COHP functions. These two compounds are the only stable ternary phases in the (Cs,Rb,K,Na)-Au-Zn systems, emphasizing the special bonding and packing requirements in these sodium structures.
Room temperature rate constants for the reaction of OH with selected chlorinated and oxygenated hydrocarbons

A study was conducted to measure the hydroxyl radical rate constants using a relative rate procedure in which the photolysis of methyl nitrite was the source of OH. During the course of this study, the OH rate constant was measured for a number of chlorinated solvents for which measurements have not previously been reported or for which there are few reliable measurements. Room temperature OH rate constants are presented for six chlorinated hydrocarbons (allyl chloride, benzyl chloride, chlorobenzene, epichlorohydrin, trichloroethylene, and vinylidene chloride) and four oxygenated hydrocarbons (acrolein, methacrolein, methyl ethyl ketone, and propylene oxide). Also included are OH rate constants for alkanes (ethane, propane, isobutane, and cyclohexane), alkenes (trans−2-butene and isoprene), and aromatic hydrocarbons (benzene, toluene, o−, m−, and p-xylene). Rate constants for compounds not previously reported include vinylidene chloride (1.49 ± 0.21 × 10−11 cm3 molecule−1 s−1) and benzyl chloride (2.96 ± 0.15 × 10−12 cm3 molecule−1 s−1). The analysis for chlorinated hydrocarbons included a correction for possible chlorine atom reactions.
The home as factory floor : employment and remuneration of home-based workers

Home-based work, defined as nonprofessionals who perform market work from their homes, is an increasingly recognized form of employment in Latin America. The majority of the research on this segment of the labor force relies on small sample, qualitative data, which find that home-based workers are women, children, and adults with disabilities with low skills who work long hours for low wages. The authors use a large random sample of control groups of non-home-based workers, including men, in their analysis and examine the home-based work sector in Brazil, Ecuador, and Mexico in 1999. Their results show that in all three countries, women are overrepresented among home-based workers, particularly older women, those with low levels of education, and those with children or spouses, unlike men for whom these factors do not matter. Female home-based workers earn 25-60 percent less an hour than do non-home-based working women and they work one-third to one-half as many hours each week. Home-based working men, on the other hand, earn 0-17 percent less than do men who do not work from their homes, and they only work 10 percent fewer hours a week. The wage and work hour gaps for women are largely related to marital status, not the presence of children, suggesting that simply being the primary caregiver in the household, regardless of the actual time constraints (children) is the key factor to differences between home-based working women and those who work outside of their homes.
On channel estimation using superimposed training and first-order statistics

Channel estimation for single-input multiple-output (SIMO), possibly time-varying, channels is considered using only the first-order statistics of the data. The time-varying channel is assumed to be described by a complex exponential basis expansion model (CE-BEM). A periodic (non-random) training sequence is arithmetically added (superimposed) at a low power to the information sequence at the transmitter before modulation and transmission. Recently superimposed training has been used for time-invariant channel estimation assuming no mean-value uncertainty at the receiver. We propose a different method that explicitly exploits the underlying cyclostationary nature of the periodic training sequences. It is applicable to both time-invariant and time-varying systems. Unlike existing approaches we allow mean-value uncertainty at the receiver. Illustrative computer simulation examples are presented.
THE TRENDS HIGH-CONTRAST IMAGING SURVEY. III. A FAINT WHITE DWARF COMPANION ORBITING HD 114174

The nearby Sun-like star HD 114174 exhibits a strong and persistent Doppler acceleration indicating the presence of an unseen distant companion. We have acquired high-contrast imaging observations of this star using NIRC2 at Keck and report the direct detection of the body responsible for causing the "trend." HD 114174 B has a projected separation of 692 ± 9 mas (18.1 AU) and is 10.75 ± 0.12 mag (contrast of 5 × 10^(–5)) fainter than its host in the K-band, requiring aggressive point-spread function subtraction to identify. Our astrometric time baseline of 1.4 yr demonstrates physical association through common proper motion. We find that the companion has absolute magnitude, M_J = 13.97 ± 0.11, and colors, J – K = 0.12 ± 0.16 mag. These characteristics are consistent with an ≈T3 dwarf, initially leading us to believe that HD 114174 B was a substellar object. However, a dynamical analysis that combines radial velocity measurements with available imaging data indicates a minimum mass of 0.260 ± 0.010 M_☉. We conclude that HD 114174 B must be a white dwarf. Assuming a hydrogen-rich composition, atmospheric and evolutionary model fits yield an effective temperature T_(eff) = 8200 ± 4000 K, surface gravity log g = 8.90 ± 0.02, and cooling age of t_c ≈ 3.4 Gyr, which is consistent with the 4.7^(+2.3)_(-2.6) Gyr host star isochronal age estimate. HD 114174 B is a benchmark object located only 26.14 ± 0.37 pc from the Sun. It may be studied at a level of detail comparable to Sirius and Procyon, and used to understand the link between the mass of white dwarf remnants with that of their progenitors.
Least squares type algorithms for identification in the presence of modeling uncertainty

The celebrated least squares and LMS (least-mean-squares) are system identification approaches that are easily implementable, need minimal a priori assumptions, and have very nice identification properties when the uncertainty in measurements is only due to noises and not due to unmodeled behavior of the system. When there is uncertainty present due to an unmodeled part of the system as well, however, the performance of these algorithms can be poor. Here the authors propose a "modified" weighted least squares algorithm that is geared toward identification in the presence of both unmodeled dynamics and measurement disturbances. The algorithm uses very little a priori information and is easily implementable in a recursive fashion. Through an example the authors demonstrate the improved performance of the proposed approach. Motivated by a certain worst-case property of the LMS algorithm, an H/sub /spl infin// estimation algorithm is also proposed for the same objective of identification in the presence of modeling uncertainty. >
Stereoselective Synthesis of Highly Substituted Cyclopentenones through [4+1] Annulations of Trialkylsilyl Vinyl Ketenes with α‐Benzotriazolyl Organolithium Compounds

Cyclopentenones serve as valuable synthetic building blocks and are themselves key features in the structure of a number of prostaglandins[1] and other bioactive natural products. Popular strategies for the construction of this important ring system include the intramolecular aldol reaction, the Nazarov cyclization,[2] the Rautenstrauch rearrangement,[3] and the Pauson–Khand reaction.[4,5] Only a few general [4+1] routes to five-membered carbocycles have been reported to date, one example being the method we developed based on anion-accelerated vinylcyclopropane rearrangements.[6,7] Recently, studies by us[8] and others[9] have led to several new [4+1] approaches to the synthesis of the 2-cyclopentenone ring system. Herein, we report a new variant of our stereo-controlled [4+1] annulation strategy that provides especially efficient access to highly substituted and functionalized cyclopentenones.
Effects of Financial Incentives on the Breakdown of Mutual Trust

Disagreements between psychologists and economists about the need for and size of financial incentives continue to be hotly discussed. We examine the effects of financial incentives in a class of interactive decision-making situations, called centipede games, in which mutual trust is essential for cooperation. Invoking backward induction, the Nash equilibrium solution for these games is counterintuitive. Our previous research showed that when the number of players in the centipede game is increased from two to three, the game is iterated in time, the players are rematched, and the stakes are unusually high, behavior approaches equilibrium play. Results from the present study show that reducing the size of the stakes elicits dramatically different patterns of behavior. We argue that when mutual trust is involved, the magnitude of financial incentives can induce a considerable difference.
Chemoselective Amination of Propargylic C(sp3)H Bonds by Cobalt(II)‐Based Metalloradical Catalysis

Highly chemoselective intramolecular amination of propargylic C(sp(3))-H bonds has been demonstrated for N-bishomopropargylic sulfamoyl azides through cobalt(II)-based metalloradical catalysis. Supported by D(2h)-symmetric amidoporphyrin ligand 3,5-Di(t)Bu-IbuPhyrin, the cobalt(II)-catalyzed C-H amination proceeds effectively under neutral and nonoxidative conditions without the need of any additives, and generates N2 as the only byproduct. The metalloradical amination is suitable for both secondary and tertiary propargylic C-H substrates with an unusually high degree of functional-group tolerance, thus providing a direct method for high-yielding synthesis of functionalized propargylamine derivatives.
Interacting fermionic topological insulators/superconductors in three dimensions

Symmetry protected topological (SPT) phases are a minimal generalization of the concept of topological insulators to interacting systems. In this paper, we describe the classification and properties of such phases for three-dimensional (3D) electronic systems with a number of different symmetries. For symmetries representative of all classes in the famous 10-fold way of free-fermion topological insulators/superconductors, we determine the stability to interactions. By combining with results on bosonic SPT phases, we obtain a classification of electronic 3D SPT phases for these symmetries. In cases with a normal $U(1)$ subgroup we show that this classification is complete. We describe the nontrivial surface and bulk properties of these states. In particular, we discuss interesting correlated surface states that are not captured in a free-fermion description. We show that in many, but not all, cases, the surface can be gapped while preserving symmetry if it develops intrinsic topological order.
The Effects of the Mechanical Properties of the Confinement Material on Electromigration in Metallic Interconnects

New low-dielectric-constant inter-level dielectrics are being investigated as alternatives to SiO2 for future integrated circuits. In general, these materials have very different mechanical properties from SiO2. In the standard model, electromigration-induced stress evolution caused by changes in the number of available lattice sites in interconnects is described by an effective elastic modulus, B. Finite element calculations have been carried out to obtain B as a function of differences in the modulus, E, of interlevel dielectrics, for several stress-free homogeneous dilational strain configurations, for several line aspect ratios, and for different metallization schemes. In contradiction to earlier models, we find that for Cu-based metallization schemes with liners, a decrease in E by nearly two orders of magnitude has a relatively small effect on B, changing it by less than a factor of 2. However, B, and therefore the reliability of Cu interconnects can be strongly dependent on the modulus and thickness of the liner material.
Direct hydrocarbon solid oxide fuel cells.

Solid Oxide Fuel Cells (SOFCs) are one of the most promising technologies for future efficient conversion of the chemical energy stored in fuels to electrical energy. One of the primary advantages of SOFCs is the potential to operate with a wide variety of fuels. While H2 is the fuel of choice for most fuel cells, operation with fossil-derived and bio-derived hydrocarbon fuels would bypass the costly requirement of a new H2 infrastructure, and accelerate adoption of fuel cell technology. This is feasible as SOFCs transport oxygen anions from the air electrode (cathode) to the fuel electrode (anode). The primary barrier to the realization of fuel flexible SOFCs is the anode material set. Traditional SOFC anodes are based on Ni composites. While these are very efficient for H2 and CO fuels, Ni catalyzes graphite formation from dry hydrocarbons, leading to rapid degradation of cell performance and possible mechanical failure. This motivates the development of new anode materials and composites. The principle requirements of an anode are oxygen anion conductivity, electronic conductivity, and electrocatalytic activity toward the desired reaction. This entry reviews the primary issues in direct hydrocarbon anode development and discusses the new materials and composites that have been developed to meet this challenge.
Efficient digital to analog encoding

An important issue in analog circuit design is the problem of digital-to-analog conversion, i.e., the encoding of Boolean variables into a single analog value which contains enough information to reconstruct the values of the Boolean variables. A natural question is: what is the complexity of implementing the digital-to-analog encoding function? That question was answered by Wegener (see Inform. Processing Lett., vol.60, no.1, p.49-52, 1995), who proved matching lower and upper bounds on the size of the circuit for the encoding function. In particular, it was proven that [(3n-1)/2] 2-input arithmetic gates are necessary and sufficient for implementing the encoding function of n Boolean variables. However, the proof of the upper bound is not constructive. In this paper, we present an explicit construction of a digital-to-analog encoder that is optimal in the number of 2-input arithmetic gates. In addition, we present an efficient analog-to-digital decoding algorithm. Namely, given the encoded analog value, our decoding algorithm reconstructs the original Boolean values. Our construction is suboptimal in that it uses constants of maximum size n log n bits; the nonconstructive proof uses constants of maximum size 2n+[log n] bits.
Dynamical evolution of spatiotemporal patterns in mammalian middle cortex

The spatiotemporal structure of brain oscillations are important in understanding neural function. We analyze oscillatory episodes from isotropic preparations from the middle layers of a mammalian cortex which display irregular and chaotic spatiotemporal wave activity, within which spontaneously emerge spiral and plane waves. The dimensionality of these dynamics shows a consistent decrease during the middle of these episodes, regardless of the presence of simple spiral or plane waves. It is important to define the relevant biological order parameters which govern these dynamical bifurcations.
Dimensionally Reduced Chern-Simons Terms and Their Solitons

We consider models in which nonrelativistic matter fields interact with gauge fields whose dynamics are governed by the Chern-Simons term. The relevant equations of motion are derived and reduced dimensionally in time or in space. Interesting solitonic equations emerge and their solutions are described. Finally, we consider a Chern-Simons term in three-dimensional Euclidean space, reduced by spherical symmetry, and we discuss its effect on monopole and instanton solutions.
Selection on Observed and Unobserved Variables: Assessing the Effectiveness of Catholic Schools

In this paper we measure the effect of Catholic high school attendance on educational attainment and test scores. Because we do not have a good instrumental variable for Catholic school attendance, we develop new estimation methods based on the idea that the amount of selection on the observed explanatory variables in a model provides a guide to the amount of selection on the unobservables. We also propose an informal way to assess selectivity bias based on measuring the ratio of selection on unobservables to selection on observables that would be required if one is to attribute the entire effect of Catholic school attendance to selection bias. We use our methods to estimate the effect of attending a Catholic high school on a variety of outcomes. Our main conclusion is that Catholic high schools substantially increase the probability of graduating from high school and, more tentatively, attending college. We find little evidence of an effect on test scores.
Chicken or egg? A hierarchy of homotopy algebras

We start by clarifying and extending the multibraces notation, which economically describes substitutions of multilinear maps and tensor products of vectors. We give definitions and examples of weakly homotopy algebras, homotopy Gerstenhaber and Gerstenhaber bracket algebras, and homotopy Batalin-Vilkovisky algebras. We show that a homotopy algebra structure on a vector space can be lifted to its Hochschild complex, and also suggest an induction method to generate some of the explicit (weakly) homotopy Gerstenhaber algebra maps on a topological vertex operator algebra (TVOA), their existence having been indicated by Kimura, Voronov, and Zuckerman in 1996 (later amended by Voronov). The contention that this is the fundamental structure on a TVOA is substantiated by providing an annotated dictionary of weakly homotopy BV algebra maps and identities found by Lian and Zuckerman in 1993.
A rate-distortion exponent approach to multiple decoding attempts for Reed-Solomon codes

Algorithms based on multiple decoding attempts of Reed-Solomon (RS) codes have recently attracted new attention. Choosing decoding candidates based on rate-distortion theory, as proposed previously by the authors, currently provides the best performance-versus-complexity trade-off. In this paper, an analysis based on the rate-distortion exponent is used to directly minimize the exponential decay rate of the error probability. This enables rigorous bounds on the error probability for finitelength RS codes and leads to modest performance gains. As a byproduct, a numerical method is derived that computes the rate-distortion exponent for independent non-identical sources. Analytical results are given for errors/erasures decoding.
Understanding Willingness-to-Pay Formation of Repeat Bidders in Sequential Online Auctions

A growing number of vendors are using a sequence of online auctions to sell large inventories of identical items. Although bidding strategies and bidder behavior in single auctions have been extensively studied, limited research exists on bidding in sequential auctions. We seek to explain how bidders in such an environment learn from the information, and form and update their willingness to pay (WTP). Using a large data set from an online auction retailer, we analyze the evolution of the bidders' WTP as well as the effect of auction design on bidders' WTP in sequential auctions. We see our study in the context of a longitudinal field experiment, in which we were able to track actions of repeat bidders over an extended period of time. Our results show that bidders' WTP in sequential auctions can be explained from their demand characteristics, their participation experience in previous auctions, outcomes in previous auctions, and auction design parameters. We also observe, characterize, and measure what we call a modified demand reduction effect exhibited across different auctions, over time, by multiunit demand bidders. Our findings are important to enable better auction mechanism design, and more sophisticated bidding tools that explore the rich information environment of sequential auctions.
ESTIMATING THE EARLY EXERCISE PREMIUM OF AMERICAN PUT INDEX OPTIONS

This paper examines empirically the value of early exercise by testing the ability of two American put valuation models to predict the early exercise premium for the S&P 100 American put options. An accuracy test and a quality test are performed on (1) the MacMillan and Barone-Adesi and Whaley model, and (2) the Carr, Jarrow and Myneni model. The test results show that early exercise premium is significant regardless of moneyness. Moreover, consistent with the theory, the value of early exercise is significantly negatively related to moneyness and interest rates and significantly positively related to time to maturity and to the volatility of the underlying index. Both American put valuation models examined do not fully capture the value of early exercise embedded in American put prices.
Managing Food Industry Business and Financial Risks with Commodity-Linked Credit Instruments

This study reviews the use and structure of commodity-linked credit instruments. It is argued that in the absence of contingent markets food firms face increasing financial risk-reduced investment, and limited access to debt markets. One strategy is to issue commodity-linked credit whose payment structure is linked to the price of an underlying commodity. In some cases, a commodity-linked bond (CLB) can be structured to provide an incentive to investors by sharing in profit gains. If the goal is to hedge financial risks, CLBs can also be constructed that reduce the loan principle or coupons depending on price movements. [JEL classifications: G13, Q13, Q14] © 2006 Wiley Periodicals, Inc. Agribusiness 22: 523–545, 2006.
Overview of linear collider designs

Linear collider design and development have become focused on a center-of-mass energy E/sub CM/ = 0.5 TeV and a luminosity L = 5/spl times/10/sup 33/ cm/sup -2/sec/sup -1/. There are diverse approaches to meeting these general objectives. The diversity arises from different judgements about the ease of developing new and improving existing technology, costs, extension to higher energies, experimental backgrounds and center-of mass energy spectrum, tolerances and beam power. The parameters of possible colliders are given, which are based on a compilation made by Loew at the LC-92 Conference and is reproduced with his permission. The colliders described are: TESLA (being developed by an international collaboration) which is based on superconducting RF. All the others would use room temperature RF. DLC (DESY/Darmstadt) which uses S-band (3 GHz) RF where there is extensive operating experience. NLC (SLAC) which uses higher frequency X-band (11.4 GHz) RF in a modulator-klystron-accelerator configuration similar to S-band linacs. JLC-1 (KEK) which has three frequency options, S-band, C-band (5.7 GHz), and X-band. Multiple bunches are accelerated in each RF pulse as they are in TESLA, DLC, and NLC. VLEPP (INP) which employs a single high intensity bunch rather than multiple bunches. CLIC (CERN) which is a two-beam accelerator with klystrons replaced by an RF power source based on a high-current, low-energy beam travelling parallel to the high energy beam. The discussion below focuses on some of the common themes of these designs and the differences between them. >
An efficient reconciliation algorithm for social networks

People today typically use multiple online social networks (Facebook, Twitter, Google+, LinkedIn, etc.). Each online network represents a subset of their "real" ego-networks. An interesting and challenging problem is to reconcile these online networks, that is, to identify all the accounts belonging to the same individual. Besides providing a richer understanding of social dynamics, the problem has a number of practical applications. At first sight, this problem appears algorithmically challenging. Fortunately, a small fraction of individuals explicitly link their accounts across multiple networks; our work leverages these connections to identify a very large fraction of the network. Our main contributions are to mathematically formalize the problem for the first time, and to design a simple, local, and efficient parallel algorithm to solve it. We are able to prove strong theoretical guarantees on the algorithm's performance on well-established network models (Random Graphs, Preferential Attachment). We also experimentally confirm the effectiveness of the algorithm on synthetic and real social network data sets.
Structural damage assessment using a generalized minimum rank perturbation theory

Recently, the authors proposed computationally attractive algorithms to determine the location and extent of structural damage for undamped structures assuming damage results in a localized change in stiffness properties. The algorithms make use of a finite-element model and a subset of measured eigenvalues and eigenvectors. The developed theories approach the damage location and extent problem in a decoupled fashion. First, a theory is developed to determine the location of structural damage. With location determined, a damage extent theory is then developed. The damage extent algorithm is a minimum rank perturbation, which is consistent with the effects of many classes of structural damage on a finite-element model. In this work, the concept of the minimum rank perturbation theory (MRPT) is adopted to determine the damage extent on the mass properties of an undamped structure. In addition, the MRPT is extended to the case of proportionall y damped structures. For proportionally damped structures, the MRPT is used to find the damage extent in any two of the three structural property matrices (mass, damping, or stiffness). Finally, illustrative case studies using both numerical and actual experimental data are presented. HE advent of the Space Shuttle has prompted considerable attention to the design and control of large space structures. Due to the large size and complexity of envisioned structures, as well as the use of advanced materials to reduce structural weight, it may become necessary to develop a structural health monitoring system to detect and locate structural damage as it occurs. From experience gained in the machinery health monitoring field, one would expect the vibration signature of the structure, either frequency response functions and/or modal parameters, to provide useful information in determining the location and extent of structural damage. Assume that a refined finite element model (FEM) of the structure has been developed before damage has occurred. By refined, we mean that the measured and analytical modal properties are in agreement. Next, assume that at a later date some form of structural damage has occurred. If significant, the damage will result in a change in the structures modal parameters. The question is: can the discrepancy between the original FEM modal properties and postdamage modal properties be used to ascertain structural damage? Most prior work in damage detection has used the general framework of FEM refinement (system identification) in the development of damage assessment algorithms. The motivation behind the development of FEM refinement techniques is based on the need to validate engineering FEMs before their acceptance as the basis for final design analysis. The standard problem has been to seek a refined FEM that is as close to the original FEM and whose modal properties are in agreement with those that are measured subject to various constraints such as symmetry and sparsity preservation. A considerable amount of work in this area has been
Inflammatory markers are unrelated to physical activity, performance, and functioning in hemodialysis.

Abstract Objective: To determine the associations among dietary intake and inflammatory cytokines with physical activity, function, and performance in maintenance dialysis patients. Design: Cross-sectional analysis of cohort study. Setting: University-affiliated dialysis units, general clinical research center. Subjects: Multiethnic cohort of maintenance hemodialysis patients. Main Outcome Measures: Physical activity by accelerometry; physical performance by gait speed, stair climbing, and chair raising; physical functioning by the Medical Outcomes Study Short Form 36-item questionnaire subscale scores; and maximal and adjusted activity scores of human activity profile. Results: Levels of inflammatory cytokines were uniformly high. Tumor necrosis factor-α was directly correlated with dietary protein and energy intake; no other cytokines were directly or inversely correlated with intake. Dietary intake was associated with physical activity, as expected, and not significantly associated with performance or function (with the exception of gait speed). There were no significant associations among inflammatory cytokines and physical activity, performance, or function. Conclusion: Although dietary intake and inflammation may independently influence traditional proxies of nutritional status, this analysis provides no evidence for a link between cytokines and physical activity, performance, or function in hemodialysis patients. More research is required to understand the role of cytokines in protein energy malnutrition and the mechanisms of wasting and functional decline in the dialysis population.