cssi/SciSciGPT-SciSciNet huggingface dataset:
Albedos of Small Jovian Trojans

We present thermal observations of 44 Jovian Trojan asteroids with diameters D ranging from 5 to 24 km. All objects were observed at a wavelength of 24 μm with the Spitzer Space Telescope. Measurements of the thermal emission and of scattered optical light, mostly from the University of Hawaii 2.2 m Telescope, together allow us to constrain the diameter and geometric albedo of each body. We find that the median R-band albedo of these small Jovian Trojans is about 0.12, much higher than that of large Trojans with D>57 km (0.04). Also the range of albedos among the small Trojans is wider. The small Trojans' higher albedos are also glaringly different from those of cometary nuclei, which match our sample Trojans in diameter, however, they roughly match the spread of albedos among (much larger) Centaurs and trans-Neptunian objects. We attribute the Trojan albedos to an evolutionary effect: the small Trojans are more likely to be collisional fragments and so their surfaces would be younger. A younger surface means less cumulative exposure to the space environment, which suggests that their surfaces would not be as dark as those of the large, primordial Trojans. In support of this hypothesis is a statistically significant correlation of higher albedo with smaller diameter in our sample alone and in a sample that includes the larger Trojans. This correlation of albedo and radius implies that the true size distribution of small Trojans is shallower than the visible magnitude distribution alone would suggest, and that there are approximately half the Trojans with D>1 km than previously estimated.
Good and bad credit contagion: Evidence from credit default swaps

Abstract This study examines the intra-industry information transfer effect of credit events, as captured in the credit default swaps (CDS) and stock markets. Positive correlations across CDS spreads imply that contagion effects dominate, whereas negative correlations indicate competition effects. We find strong evidence of contagion effects for Chapter 11 bankruptcies and competition effects for Chapter 7 bankruptcies. We also introduce a purely unanticipated event, in the form of a large jump in a company's CDS spread, and find that this leads to the strongest evidence of credit contagion across the industry. These results have important implications for the construction of portfolios with credit-sensitive instruments.
Flexibility and performance of parallel file systems

As we gain experience with parallel file systems, it becomes increasingly clear that a single solution does not suit all applications. For example, it appears to be impossible to find a single appropriate interface, caching policy, file structure, or disk-management strategy. Furthermore, the proliferation of file-system interfaces and abstractions make applications difficult to port.
Color-accurate underwater imaging using perceptual adaptive illumination

Capturing color in water is challenging due to the heavy non-uniform attenuation of light in water across the visible spectrum, which results in dramatic hue shifts toward blue. Yet observing color in water is important for monitoring and surveillance as well as marine biology studies related to species identification, individual and group behavior, and ecosystem health and activity monitoring. Underwater robots are equipped with motor control for large scale transects but they lack sensors that enable capturing color-accurate underwater images. We present a method for color-accurate imaging in water called perceptual adaptive illumination. This method dynamically mixes the illumination of an object in a distance-dependent way using a controllable, multi-color light source. The color mix compensates correctly for color loss and results in an image whose color composition is equivalent to rendering the object in air. Experiments were conducted with a color palette in the pool and at three different coral reefs sites, and with an underwater robot collecting image data with the new sensor.
Synthesis and 13C NMR of (trifluoromethyl)hydroxypyrazoles

Reaction of ethyl 4,4,4-trifluoroacetoacetate with methylhydrazine produced not only the previously reported 5-hydroxy-3-(trifluoromethyl)pyrazole 1 but also its unknown isomer the 3-hydroxy-5-(trifluoromethyl)pyrazole 4. The structure assignements are etablished based on 13 C NMR spectra. Compound 1 was converted to 5-chloro-3-(trifluoromethyl)pyrazolecarboxylic acid 3 in two steps.
Renormalization group improved gap equation for color superconductors

Abstract The renormalization group is used to resum leading logarithmic contributions of the form α s n+1 β 0 n log n (Δ/μ) to the gap equation appropriate for high-density QCD. The scale dependence of the strong coupling constant α s increases the gap by a factor of exp 33 16 π 2 4 −1 ∼20 in the small coupling limit.
Discontinuity of the exchange-correlation potential from a density-functional viewpoint.

An expression for the discontinuity of the exchange-correlation potential ${v}_{\mathrm{xc}}$ of an insulator is derived entirely within the framework of density-functional theory. The discontinuity is expressed in terms of changes of the exchange-correlation energy, ${E}_{\mathrm{xc}}$, of a perfect N-particle insulator when (a) a conduction electron is introduced, (b) a valence electron is removed, and (c) the external perturbation is applied to the perfect insulator (without changing N) such that the density change is equal to minus the sum of the density changes in (a) and (b).
Aging of cast duplex stainless steels in LWR systems

Abstract A program is being conducted to investigate the significance of in-service embrittlement of cast duplex stainless steels under light-water reactor operating conditions. The existing data are evaluated to determine the expected embrittlement of cast components during the operating lifetime of reactors and to define the objectives and scope of the investigation. This presentation describes the status of the program. Data for the metallurgical characterization of the various cast stainless steels used in the investigation are presented. Charpy impact tests on short-term aged material indicate that CF-3 stainless steels are less susceptible to embrittlement than CF-8 or CF-8M stainless steels. Microstructural characterization of cast stainless steels that were obtained from Georg Fischer Co. and aged for up to 70000 h at 300, 350, and 400°C reveals the formation of four different types of precipitates that are not α'. Embrittlement of the ferrite phase is primarily due to pinning of the dislocations by two of these precipitates, designated as Type M and Type X. The ferrite phase is embrittled after ≈ 8 y at 300°C and shows cleavage fracture. Examination of the fracture surfaces of the impact-test specimens indicates that the toughness of the long-term aged material is determined by the austenite phase.
Bohmian Mechanics and Quantum Information

Many recent results suggest that quantum theory is about information, and that quantum theory is best understood as arising from principles concerning information and information processing. At the same time, by far the simplest version of quantum mechanics, Bohmian mechanics, is concerned, not with information but with the behavior of an objective microscopic reality given by particles and their positions. What I would like to do here is to examine whether, and to what extent, the importance of information, observation, and the like in quantum theory can be understood from a Bohmian perspective. I would like to explore the hypothesis that the idea that information plays a special role in physics naturally emerges in a Bohmian universe.
Velocity Measurements in a Pressure-Driven Three-Dimensional Compressible Turbulent Boundary Layer

The flow characteristics of a three-dimensional, compressible, turbulent boundary layer have been investigated experimentally. The three dimensionality was generated by inclining a cylindrical afterbody at 10-deg angle of attack to a Mach 2.45 freestream. The objective was to determine the mechanisms that govern the growth and behavior of pressure-driven, three-dimensional, compressible, turbulent boundary layers. Laser Doppler velocimetry was used to determine mean velocity components and turbulence statistics
Characterization of the degraded microstructures of a platinum aluminide coating

Abstract The degradation of a platinum modified aluminide (PtAl) coating and a CMSX-4 superalloy substrate were investigated for cyclic and quasi-isothermal heating to 1200 °C. To accelerate the oxidation of the specimens, the thermally grown oxide (TGO) was removed at 10 h intervals. For up to 80 h of exposure, comparisons of specimens with periodic oxide removal and those without oxide removal were made. Qualitatively, the major changes to the bond coat were associated with phase changes from β-(Ni,Pt)Al to γ′-(Ni 3 Al) and precipitate coarsening. This evolution was quantified through backscatter scanning electron microcopy and image analysis. With instrumented indentation, the room temperature coating modulus was also measured at 10 h intervals. Additional results include observations of differences in waviness of the bond coat surface for cyclic, quasi-isothermal, and true-isothermal heating, and observations of rafting near the substrate/coating interface. The differences between cyclic and quasi-isothermal heating indicate that stresses associated with cooling and heating significantly alter microstructural evolution.
Price increasing competition? Experimental evidence

Abstract Economic intuition suggests competition lowers prices. However, recent theoretical work reveals a monopolist may prefer to charge a lower price than a seller facing a competitor with a differentiated product depending upon the joint distribution of buyer values for the products. We explore this relationship using controlled laboratory experiments. Our results indicate price increasing competition is rare due in part to overly intense competition, but after controlling for such behavioral reactions, we find some support for the model. We also explore pricing dynamics and find that sellers are more sensitive to their rivals when buyer values are positively correlated.
Chiral Invariance of Massive Fermions

We show that a massive fermion theory, while not invariant under the conventional chiral transformation, is invariant under a m-deformed chiral transformation. These transformations and the associated conserved charges are nonlocal but reduce to the usual transformations and charges when m=0. The m-deformed charges commute with helicity and satisfy the conventional chiral algebra.
PLEM: A computer program for passive learning, stochastic control experiments

Abstract The benefits of using stochastic control methods to solve real world optimal policy problems in economics needs to be demonstrated. A potentially convincing demonstration for any problem is to compare the actual policy settings over time with those which would have been optimal had stochastic control methods been employed. If the optimal policy is more efficient at meeting targets (or meets them more accurately for the same cost) than the actual policy, then the methods are likely to find their way into the toolboxes of managers, planners, and other decision-makers. While the analytical properties of myriad economic control problems are becoming increasingly well-known, and while numerical methods and computational capacities have grown rapidly in recent years, there is a striking lack of software available to solve actual stochastic control problems. This paper reports on the development of a computer program to perform passive learning control on systems for which new information (about system parameters and forecasts of exogenous variables) is available to decision-makers each period. Upon execution the program computes the optimal path and presents a comparison table of the actual and optimal state and control variables over time, as well as the respective values of the objective functions.
Ellipsoidal collapse and the redshift-space probability distribution function of dark matter

We use the physics of ellipsoidal collapse to model the probability distribution function (PDF) of the smoothed dark matter density field in real and redshift space. We provide a simple approximation to the exact collapse model which clearly shows how the evolution can be thought of as a modification of the spherical evolution model as well as of the Zeldovich approximation. In essence, our model specifies how the initial smoothed overdensity and shear fields can be used to determine the shape and the size of the region at later times. We use our parametrization to extend previous work on the real-space PDF so that it predicts the redshift-space PDF as well. Our results are in good agreement with the measurements of the PDF in simulations of clustering from Gaussian initial conditions down to scales on which the rms fluctuation is slightly greater than unity. We also show how the highly non-Gaussian non-linear redshifted density field in a numerical simulation can be transformed so that it provides an estimate of the shape of the initial real-space PDF. When applied to our simulations, our method recovers the initial Gaussian PDF, provided the variance in the non-linear smoothed field is less than 4.
Improved fast integer sorting in linear space

We present improved fast deterministic algorithm for integer sorting in linear space. Our algorithm sorts n integers in linear space in O(n log log n log log log n) time. This improves the O(n(log log n)3/2) time bound given in [6]. When the n integers in {0,1,…, m - 1} to be sorted satisfying log m g(log n)2+∈, 0
Synthetic Approaches to Homocamptothecin Antitumor Agents

Abstract Homocamptothecins are proving to be an especially interesting class of anti-cancer agents because they resemble standard camptothecins in cytotoxicity but have very different pharmacodyanamic properties. This review summarizes synthetic approaches to the parent homocamptothecin and its analogs. Three powerful and general routes—the Lavergne–Comins route, the cascade radical annulation route, and the Friedlander route—have been put into place to make homocamptothecins. These routes are compared and contrasted. Together, they have driven the SAR, preclinical, and clinical development of this class of anti-cancer agents.
Anisotropy of the energy gap in the insulating phase of the U-t-t' Hubbard model

We apply a diagrammatic expansion method around the atomic limit ( ) for the U-t-t ' Hubbard model at half filling and finite temperature by means of a continued fraction representation of the one-particle Green's function. From the analysis of the spectral function we find an energy dispersion relation with a modulation of the energy gap in the insulating phase. This anisotropy is compared with experimental ARPES results on insulating cuprates.
The performance of multicast banyan networks

Multicast is the ability to transmit information from a single source node to multiple selected destination nodes in a network. Current trends in networking applications indicate that there will be an increasing demand in future networks for multicast communication. Efficient multicast communication is critical to the network performance. Banyan networks have been proposed for use in ATM high-speed communications networks and have been used for the interconnection of processors in scalable parallel computers. This paper addresses the performance issues of supporting multicast communication in banyan networks. Previous work on the performance of banyan networks has been primarily for the networks which can support only one-to-one communication (i.e., unicast banyan networks). We present here an analytical model for the performance of banyan networks which support multicast communication (i.e., multicast banyan networks). Our model yields a set of equations that can be solved for the throughput of the network. We show that the throughput of a multicast banyan network is generally higher than that of a unicast banyan network. In particular, we obtain that the throughput of a multicast banyan network is �(N), where N is the size of the network, compared with �(NlogN) for a unicast banyan network. In addition to throughput, we also derive formulas for another important performance metric, packet loss probability, for multicast banyan networks in this paper.
Functionalization of Corroles: Formylcorroles

Porphyrins and metalloporphyrins can be readily functionalized at the meso-(5,10,15,20)-positions by using a variety of reagents, the Vilsmeier formylation reaction being universally regarded as the prototypical example. On the other hand, the literature shows that corroles and metallocorroles are unusually resistant to most functionalization procedures which are common to porphyrins. The first example of peripheral functionalization of the corrole ring is now reported. Octamethylcorrole 1 readily reacts with the Vilsmeier reagent (POCl3/DMF), but the product is the 10-dimethylaminomethene derivative 2, and not the expected meso-formyl derivatives 3 or 4, as confirmed by a single crystal X-ray crystallographic study. Corrole 5, where the 10-meso-position is substituted, affords the similar product 6. When the reaction is extended to corrole 7 two different products, 8 and 9, are obtained wherein the substitution is performed at both 5- and 10-meso-positions. Unlike the case of porphyrins, no reaction occu...
Prediction of scatter in fatigue properties using discrete damage mechanics

Abstract Generic microstructures are represented via a two-dimensional discrete lattice of linear-elastic springs with a Normal distribution of static strengths. These springs represent grain boundaries and damage is constrained to intergranular cracking. The fatigue behavior is described with a Basquin law (the same in all springs), whereas damage accumulates via a Palmgren–Miner law. Lattices were ‘cycled’ under fully reversed strain and replicas with different local geometries were used to obtain statistics. Results show that geometrical disorder and load redistribution alone result in a lognormal distribution of cycles to failure at a fixed strain. Macroscopic Coffin–Manson behavior was observed, where the exponent was the same as in the Basquin law of individual springs. This indicates that lattice models can replicate experimentally observed behavior, while making it possible to study effects of microstructural and geometric variability separately. Discussion on size effects and how to extend the model to actual materials is offered.
Quantization and multilevel halftoning of color images for near-original image quality

Algorithms are investigated for the printing or display of color images at near-original image quality with a minimum number of output colors. Each algorithm consists of a quantizer that is used possibly in conjunction with halftoning. We consider both image-independent and image-dependent quantizers implemented in RGB or in the uniform color space L*u*υ*. The halftoning techniques that we use are multilevel extensions of error diffusion and ordered dither. Image quality resulting from the use of these algorithms is measured by subjective evaluation.
In search of a euro effect: Big lessons from a Big Mac Meal?

We investigate whether the adoption of the euro was accompanied by an increase in prices in member countries, and whether it promoted goods market arbitrage in the form of faster convergence to a common price. By comparing the experience of eurozone countries to non-euro European countries in a ‘difference-in-differences’ specification we net out effects on prices unrelated to the euro. We conclude that (a) there is no evidence of significant price increases associated with the adoption of the euro even for food items; and (b) there is little systematic evidence of a significant improvement in goods market integration following the euro’s introduction.
Plasma-assisted etching: Ion-assisted surface chemistry

Abstract The directional etching capabilities of certain plasma-assisted etching configurations are usually attributed to energetic positive ion bombardment. In some gas-surface systems (e.g., Si-F), energetic ion bombardment can cause a dramatic increase in the rate of reaction between gas phase species and solid surfaces. However, in other gas-surface systems (e.g., Al-Cl2), no significant increase in the reaction rate is seen upon initiation of energetic ion bombardment; in fact, sometimes a decrease is observed. In these letter situations, if directional etching is to be obtained, additional condensible species must be present in the gas phase (e.g., CClx, BClx) which tend to deposit on surfaces forming thin protective layers. The etch rate of these so-called “blocking” layers must be accelerated by energetic ion bombardment. Recent work will be described in which the primary role of ion bombardment in ion-assisted surface chemistry is discussed. That is, which of the steps in an etching process (reaction or chemisorption, product formation, product desorption) is directly influenced by energetic ion bombardment?
Big Bang Nucleosynthesis in Light of Discordant Deuterium Measurements

Two-dimensional concordance plots involving the baryon-to-photon ratio, η, and an effective number of light neutrinos, Nv, are used to discuss the overall consistency of standard big bang nucleosynthesis in light of recent determinations of the primordial deuterium (2H) abundance. Observations of high-redshift Lyα clouds have provided discordant 2H/H determinations: one cloud with a high value of 2H/H compared with the previously accepted range of (2H+3He)/H, and one system with a significantly lower value of 2H/H than those previously obtained. The high value of 2H/H agrees well with the current observationally inferred primordial abundances of 4He and 7Li for Nv = 3. The low value of 2H/H does not fit well with the current observationally inferred primordial abundance of 4He for Nv = 3. In addition, if the low value of 2H/H is indicative of the primordial deuterium abundance, then significant depletion of 7Li in old, hot Population II halo stars is probably required in order to obtain a concordant range of η, for any effective number of neutrino flavors. The use of conservative ranges for the primordial abundances of 2H, 4He, and 7Li allows the success of the standard picture for Nv=3.
In situ study of cascade defects in silver by simultaneous transmission electron microscopy and electrical resistivity measurements at low temperatures

Abstract A helium-cooled double-tilt specimen stage for transmission electron microscopy (TEM) with the capability of simultaneous electrical resistivity measurements was constructed and used to study defect-production, migration, clustering and recovery processes in ion-irradiated silver. Vacuum-evaporated thin film specimens were irradiated with 1 MeV Kr+ -ions up to a dose of 4.0 × 1010 ions cm 2 , at |T = 10 K in the microscope, using the HVEM-tandem accelerator ion beam interface system in the Argonne National Laboratory Electron Microscopy Center. Cascade defect formation during ion bombardment at the low temperature was directly observed both by TEM and electrical resistivity measurements. Ion bombardment created groups of defect clusters with strong strain fields which gave rise to TEM contrast. The specimen resistivity was increased by 16% during the irradiation. Subsequent microstructural changes and resistivity recovery during isochronal annealing were monitored up to room temperature. 58.3% of the irradiation induced resistivity was recovered, while significant reduction in the size of black spot defect clusters was observed by TEM. A small fraction of clusters disappeared, while no nucleation of new defect clusters was observed.
The quasar mass-luminosity plane - I. A sub-Eddington limit for quasars

We use 62 185 quasars from the Sloan Digital Sky Survey Data Release 5 sample to explore the relationship between black hole mass and luminosity. Black hole masses were estimated based on the widths of their Hβ, Mg ii and C iv lines and adjacent continuum luminosities using standard virial mass estimate scaling laws. We find that, over the range 0.2 < z < 4.0, the most luminous low-mass quasars are at their Eddington luminosity, but the most luminous high-mass quasars in each redshift bin fall short of their Eddington luminosities, with the shortfall of the order of 10 or more at 0.2 < z < 0.6. We examine several potential sources of measurement uncertainty or bias and show that none of them can account for this effect. We also show the statistical uncertainty in virial mass estimation to have an upper bound of ∼0.15 dex, smaller than the 0.4 dex previously reported. We also examine the highest mass quasars in every redshift bin in an effort to learn more about quasars that are about to cease their luminous accretion. We conclude that the quasar mass–luminosity locus contains a number of new puzzles that must be explained theoretically.
Foliar fungicides in alfalfa production

Treatments in the various trials included: (1) timing of fungicide applications made at either 3 to 4, or 6 to 8 in. of growth, (2) comparison of two varieties, (3) fungicide applications prior to first or second crop for new seedings, and prior to first, second, third, or fourth crop for established stands. A few treatments consisted of multiple applications per season, and (4) comparison of fungicide products Headline SC (Group 11), Quadris Flowable (Group 11), Fontelis (Group 7), and Champ WG copper hydroxide (Group M).
Skein Theory and Witten–Reshetikhin–Turaev Invariants of Links in Lens Spaces

We study the behavior of the Witten–Reshetikhin–Turaev SU(2) invariants of an arbitrary link in L(p,q) as a function of the level r−2. They are given by \(\) times one of p Laurent polynomials evaluated at \(\). The congruence class of r modulo p determines which polynomial is applicable. If p≡ 0 mod 4, the meridian of L(p,q) is non-trivial in the skein module but has trivial Witten–Reshetikhin–Turaev SU(2) invariants. On the other hand, we show that one may recover the element in the Kauffman bracket skein module of L(p,q) represented by a link from the collection of the WRT invariants at all levels if p is a prime or twice an odd prime. By a more delicate argument, this is also shown to be true for p=9.
Boiling Point and Critical Temperature of a Heterogeneous Data Set: QSAR with Atom Type Electrotopological State Indices Using Artificial Neural Networks†

Two sets of heterogeneous organic compounds were analyzed with artificial neural networks using atom type electrotopological state indices. The first set contains the boiling point for 298 compounds; 30 were placed in a testing set. The neural network model used atom type E-state indices for the 19 atom types present in the data set; the actual network used for prediction had a 19:5:1 architecture. This model produced a mean absolute error (MAE) of 3.93 K for the overall set, 3.86 for the training set, and 4.57 for the test set. The average relative percent error for 10 runs is 0.94% for the whole data set and 1.12% for the test set. The second set contains critical temperatures for 165 compounds; 18 were placed in the testing set. The neural network possessed a 19:4:1 architecture and produced an MAE of 4.52 K for the whole set, 4.39 K for the training set, and 5.59 K for the test set. The average relative percent error for 5 runs is 0.77% for the whole data set and 0.95% for the test set.
Carbon nanotube-based heterostructures for solar energy applications

One means of combining the unique physical and chemical properties of both carbon nanotubes and complementary material motifs (such as metal sulfide quantum dots (QDs), metal oxide nanostructures, and polymers) can be achieved by generating carbon nanotube (CNT)-based heterostructures. These materials can be subsequently utilized as novel and interesting constituent building blocks for the assembly of functional light energy harvesting devices and because of their architectural and functional flexibility, can potentially open up novel means of using and taking advantage of existing renewable energy sources. In this review, we present the reliable and reproducible synthesis of several unique model CNT-based heterostructured systems as well as include an accompanying discussion about the charge transfer and energy flow properties of these materials for their potential incorporation into a range of practical solar energy conversion devices.
The Rotation Curves of Dwarf Galaxies: A Problem for Cold Dark Matter?

We address the issue of accuracy in recovering density profiles from observations of rotation curves of galaxies. We observe and analyze our models in much the same way as observers do the real galaxies. Our models include stellar disks, disks with bars, and small bulges. We find that the tilted-ring model analysis produces an underestimate of the central rotational velocity. In some cases the galaxy halo density profile seems to have a flat core, while in reality it does not. We identify three effects that explain the systematic biases: inclination, small bulge, and bar. Inclination effects are due to the finite thickness of the disk, bar, or bulge. Admixture of a nonrotating bulge component reduces the rotational velocity. A small (200-500 pc) bulge may be overlooked, leading to systematic bias even on relatively large (~1 kpc) distances. In the case of a disk with a bar, the underestimate of the circular velocity is larger because of a combination of noncircular motions and random velocities. The effect of the bar depends on the angle that the bar makes with the line of sight. Signatures of bars can be difficult to detect in the surface brightness profiles of the model galaxies. The variations of inclination angle and isophote position angle with radius are more reliable indicators of bar presence than the surface brightness profiles. The systematic biases in the central ~1 kpc of galaxies are not large. Each effect separately gives typically a few km s-1 error, but the effects add up. In some cases the error in circular velocity was a factor of 2, but typically we get about a 20% effect. The result is the false inference that the density profile of the halo flattens in the central parts. Our observations of real galaxies show that for a large fraction of galaxies the velocity of gas rotation (as measured by emission lines) is very close to the rotation of the stellar component (as measured by absorption lines). This implies that the systematic effects discussed in this paper are also applicable both for the stars and emission-line gas.
Nickel-catalyzed cycloadditions of unsaturated hydrocarbons, aldehydes, and ketones.

The nickel-catalyzed cycloaddition of unsaturated hydrocarbons and carbonyls is reported. Diynes and enynes were used as coupling partners. Carbonyl substrates include both aldehdyes and ketones. R...
Wavelength-domain tracking in multiple-beam optical storage systems

Wavelength-domain tracking (WDT) is a new concept for application in multiple-beam optical storage systems. Tracking errors caused by use of multiple beams on curved tracks are avoided in WDT systems by optimizing separations of focused beam spots. The control of beam spot separations is accomplished by wavelength tuning of individual laser sources. Feasibility of WDT is demonstrated by implementation and testing of a single-beam WDT tracking servo. Also, a novel method of error signal extraction by low-frequency modulation is proposed.
A Golod-Shafarevich Equality and p-Tower Groups

Abstract Text All current techniques for showing that a number field has an infinite p -class field tower depend on one of various forms of the Golod–Shafarevich inequality. Such techniques can also be used to restrict the types of p -groups which can occur as Galois groups of finite p -class field towers. In the case that the base field is a quadratic imaginary number field, the theory culminates in showing that a finite such group must be of one of three possible presentation types. By keeping track of the error terms arising in standard proofs of Golod–Shafarevich type inequalities, we prove a Golod–Shafarevich equality for analytic pro- p -groups. As an application, we further work of Skopin [V.A. Skopin, Certain finite groups. Modules and homology in group theory and Galois theory, Zap. Naucn. Sem. Leningrad. Otdel. Mat. Inst. Steklov. (LOMI) 31 (1973) 115–139 (in Russian)], showing that groups of the third of the three types mentioned above are necessarily tremendously large. Video For a video summary of this paper, please visit http://www.youtube.com/watch?v=13GudVNQUUI .
Extended networks, porous sheets, and chiral frameworks. Thorium materials containing mixed geometry anions: Structures and properties of Th(SeO3)(SeO4), Th(IO3)2(SeO4)(H2O)3·H2O, and Th(CrO4)(IO3)2

Abstract Three novel Th(IV) compounds containing heavy oxoanions, Th(SeO 3 )(SeO 4 ) ( 1 ), Th(IO 3 ) 2 (SeO 4 )(H 2 O) 3 ·H 2 O ( 2 ), and Th(CrO 4 )(IO 3 ) 2 ( 3 ), have been synthesized under mild hydrothermal conditions. Each of these three distinct structures contain trigonal pyramidal and tetrahedral oxoanions. Compound 1 adopts a three-dimensional structure formed from ThO 9 tricapped trigonal prisms, trigonal pyramidal selenite, SeO 3 2– , anions containing Se(IV), and tetrahedral selenate, SeO 4 2– , anions containing Se(VI). The structure of 2 contains two-dimensional porous sheets and occluded water molecules. The Th centers are found as isolated ThO 9 tricapped trigonal prisms and are bound by four trigonal pyramidal iodate anions, two tetrahedral selenate anions, and three coordinating water molecules. In the structure of 3 , the Th(IV) cations are found as ThO 9 tricapped trigonal prisms. Each Th center is bound by six IO 3 1– anions and three CrO 4 2– anions forming a chiral three-dimensional structure. Second-harmonic generation of 532 nm light from 1064 nm radiation by a polycrystalline sample of 3 was observed. Crystallographic data (193 K, Mo K α, λ = 0.7 1 0 7 3 ): 1 ; monoclinic, P 2 1 / c ; a = 7.0 3 5 1 ( 5 ) A , b = 9.5 2 5 9 ( 7 ) A , c = 9.0 2 6 6 ( 7 ) A , β = 1 0 3.1 2 8 ( 1 ) , Z = 4 , R ( F ) = 2.4 7 % for 91 parameters with 1462 reflections with I > 2 σ ( I ) ; 2 , monoclinic, P 2 1 / n , a = 7.4 8 8 9 ( 9 ) A , b = 8.0 0 2 ( 1 ) A , c = 2 0.1 6 5 ( 3 ) A , β = 1 0 0.1 4 2 ( 2 ) , Z = 4 , R ( F ) = 4.7 1 % for 158 parameters with 2934 reflections with I > 2 σ ( I ) ; 3 , orthorhombic, P 2 1 2 1 2 1 , a = 7.3 6 7 2 ( 5 ) A , b = 9.3 6 1 7 ( 6 ) A , c = 1 1.9 2 0 1 ( 7 ) A , Z = 4 , R ( F ) = 2.0 4 % for 129 parameters with 2035 reflections with I > 2 σ ( I ) .
Dilatonic domain walls

Abstract A static domain wall with infinitesimal thickness is obtained in the theory of a scalar field coupled to gravity with the dilaton, i.e. the Jordan-Brans-Dicke gravity. The value of the dilaton is determined in terms of the Brans-Dicke parameter ω. In particular the metric for the wall becomes flat and the dilaton, though nontrivial, has vanishing kinetic energy (i.e. ω =0) so that there is no gravitational effect due to such a dilatonic domain wall. Written in the Einstein frame, this solution is singular.
Unifying sets and programs via dependent types

Abstract We present a foundational framework, which we call D, unifying a lazy programming language with an impredicative constructive set theory IZFR by means of dependent types. We show that unification brings many benefits to both worlds. First, D supports two paramount paradigms of creating reliable software: correctness by construction and post-construction verification, while retaining the expressiveness of set theory. Second, D provides new expressive power, which makes it possible to internalize and prove inside D the standard meta-theoretic properties of constructive systems, such as Numerical Existence Property and Program Extraction. Finally, computation arising from the programming language significantly enriches set theory, as we show that D is stronger than IZFR and that its real numbers behave in a better way.
The zero-information-limit condition and spurious inference in weakly identified models

Abstract In many econometric models the asymptotic variance of a parameter estimate depends on the value of another structural parameter in such a way that the data contain little information about the former when the latter is close to a critical value. This paper introduces the zero-information-limit-condition (ZILC) to identify such models where ‘weak identification’ leads to spurious inference. We find that standard errors tend to be underestimated in these cases, but the size of the asymptotic t-test may either be too great (the intuitive case emphasized in the ‘weak instrument’ literature) or too small as in two cases illustrated here.
Income redistribution in a Federal system of governments

Abstract Though the traditional literature in fiscal federalism argues that the Federal government should have primary responsibility for income redistribution, U.S. states are in fact actively engaged in redistribution. This paper develops a positive model of the respective roles of state and Federal governments that can rationalize this observation. Redistribution by states creates positive horizontal fiscal externalities to other states due to migration, but negative vertical fiscal externalities to the national government due to changes in reported taxable income. We forecast that states will engage in at least some redistribution, though to a lesser degree the greater are mobility relative to taxable income elasticities. The Federal government can then choose the degree of Federal redistribution to assure that the net externalities are zero. Given such policies, we then estimate the welfare weights and migration elasticities for different income groups that would generate the effective net tax schedules observed in the U.S. The parameter estimates are broadly plausible, suggesting that the model can help explain the division of responsibilities for redistribution between state and Federal governments.
Waste not, want not: The efficiency of health expenditure in emerging and developing economies

Public health spending is low in emerging and developing economies relative to advanced economies and health outputs and outcomes need to be substantially improved. Simply increasing public expenditure in the health sector, however, may not significantly affect health outcomes if the efficiency of this spending is low. This paper quantifies the inefficiency of public health expenditure and the associated potential gains for emerging and developing economies using a stochastic frontier model that controls for the socioeconomic determinants of health, and provides country-specific estimates. The results suggest that African economies have the lowest efficiency. At current spending levels, they could boost life expectancy up to about five years if they followed best practices.
A Set of Nonpolar Thymidine Nucleoside Analogues with Gradually Increasing Size

We describe a series of nonpolar nucleoside analogues having similar shapes and gradually increasing size. The structure of the nucleobase thymine was mimicked with toluene derivatives, replacing O2/O4 with hydrogen, fluorine, chlorine, bromine, and iodine. Glycosidic bonds were formed by reactions of lithiated 2,4-dihalotoluenes with a deoxyribonolactone derivative. Structural analysis by NMR showed similar conformations across the series. The compounds are useful for study of the biological recognition of nucleotides and nucleic acids.
The asymptotic distribution of a single eigenvalue gap of a Wigner matrix

We show that the distribution of (a suitable rescaling of) a single eigenvalue gap \(\lambda _{i+1}(M_n)-\lambda _i(M_n)\) of a random Wigner matrix ensemble in the bulk is asymptotically given by the Gaudin–Mehta distribution, if the Wigner ensemble obeys a finite moment condition and matches moments with the GUE ensemble to fourth order. This is new even in the GUE case, as prior results establishing the Gaudin–Mehta law required either an averaging in the eigenvalue index parameter \(i\), or fixing the energy level \(u\) instead of the eigenvalue index. The extension from the GUE case to the Wigner case is a routine application of the Four Moment Theorem. The main difficulty is to establish the approximate independence of the eigenvalue counting function \(N_{(-\infty ,x)}(\tilde{M}_n)\) (where \(\tilde{M}_n\) is a suitably rescaled version of \(M_n\)) with the event that there is no spectrum in an interval \([x,x+s]\), in the case of a GUE matrix. This will be done through some general considerations regarding determinantal processes given by a projection kernel.
Spectral flow and boundary string field theory for angled D-branes

D-branes intersecting at an arbitrary fixed angle generically constitute a configuration unstable toward recombination. The reconnection of the branes nucleates at the intersection point and involves a generalization of the process of brane decay of interest to non-perturbative string dynamics as well as cosmology. After reviewing the string spectrum of systems of angled branes, we show that worldsheet twist superfields may be used in the context of Boundary Superstring Field Theory to describe the dynamics. Changing the angle between the branes is seen from the worldsheet as spectral flow with boundary insertions flowing from bosonic to fermionic operators. We calculate the complete tachyon potential and the low energy effective action as a function of angle and find an expression that interpolates between the brane-antibrane and the Dirac-Born-Infeld actions. The potential captures the mechanism of D-brane recombination and provides for interesting new physics for tachyon decay.
Diagnostic Lamb waves in an integrated piezoelectric sensor/actuator plate: analytical and experimental studies

The objective of this study is to model the diagnostic transient waves in an integrated piezoelectric sensor/actuator plate with a view to using it as a first step towards establishing an entire structural health monitoring system and to provide experimental verification of the proposed models. PZT ceramic disks are surface mounted on an aluminum plate acting as both actuators and sensors to generate and collect A0 mode Lamb waves. Mindlin plate theory is adopted to model the propagating waves by taking both transverse shear and rotary inertia effects into account. Actuator and sensor models are both proposed. The interaction between an actuator and the host plate is modeled based on classical lamination theory. The converse piezoelectric effect of the actuator is treated as an equivalent bending moment applied to the host plate. The sensor acts as a capacitor that converts the sensed strain change into a voltage response. An analytical expression for the sensor output voltage in terms of the given input excitation signal is derived, and then experimental work is performed to verify the accuracy of the analytical model. Experimental results show that single-mode Lamb waves in the plate can be successfully generated and collected through the integrated PZT disks. The experiment also shows that the predicted sensor output for both amplitude and phase agrees well with experimentally collected data.
Why stellar astronomers should be interested in the sun

Abstract By all accounts, the Sun is a garden-variety star with an average age, a standard size, a regular temperature, norormal mass, an ordinary structure, and a typical chemical composition. Only one feature makes it special - the Sun is our star. It is located in the center of our solar system, and therefore, is responsible for all life on Earth. Astronomically speaking, the Sun is the only star in the sky that we can study up-close and personal. The unaided human eye does a better job of resolving the Sun than the finest telescope does for any other star. Stellar astronomers issue a press release whenever they can lay a few pixels of some state-of-the-art instrument across a nearby supergiant. The resolution of the Sun, however, is something we can see routinely in the magnificent images that are downloaded every day from the Transition Region and Coronal Explorer (TRACE) spacecraft. In a very real sense, the Sun is the Rosetta Stone of the Stars. Observations of the Sun deflecting starlight ushered in a new way of thinking about gravity. Zeeman effect observations of the Sun showed that stellar atmospheres were controlled by magnetic fields. The discovery of solar helium founded the science of stellar spectroscopy. Measurements of the solar mass, radius, and temperature allowed scientists to probe the interiors of stars for the first time. tim ancient age of the Sun implied that stars shine as a result of thermonuclear fusion. Observations of solar flares flamulated developments in rapid magnetic reconnection theory. The study of solar coronal holes led to a deeper understanding of the role that mass loss plays in the evolution of stars. Detailed analysis of the solar activity cycle inspired the development of Magneto-Hydrodynamic (MHD) dynamo theory. The detection and understanding; of the solar corona uncovered one of the longest unsolved mysteries in all of astrophysics — the coronal-heating problem. And the list goes on. The Sun is indeed a Laboratory for Astrophysics, but it is more than that. The Sun is a Laboratory for all of Physics. This paper describes 20th century physics discoveries that are directly attributable to solar observations. It is in the form of a Top Ten List, and was inspired originally by a talk given by Dr. Eugene N. Parker; subsequent discussions with Dr. Parker have molded it into its present form.
Highly Enantioselective Hydrogenation of Enamides Catalyzed by Chiral Phosphoric Acids

A highly enantioselective hydrogenation of enamides catalyzed by a dual chiral−achiral acid system was developed. By employing a substoichiometric amount of a chiral phosphoric acid and acetic acid, catalyst loadings as low as 1 mol % of the chiral catalyst were sufficient to provide excellent yield and enantioselectivity of the reduction product.
The structure of a metastable form of SrI2 by the X-Ray rietveld procedure

Abstract The structure of a metastable form of SrI2, designated SrI2-IV and exhibited by both SmI2 and EuI2, has been refined by the X-ray Rietveld procedure from data collected over the range 10° a = 12.328(2) A , b = 4.920(1) A , c = 8.384(1) A and Z = 4 . The seven-coordinated strontium polyhedra are more symmetrical than those in the normal form of SrI2. This structure is closely related to that of SrI2.H2O which served as the structural model.
The NASA-LaRC controls-structures interaction (CSI) technology program

One of the main difficulties encountered in the design and implementation of control systems for spacecraft is the interaction between the control system and the flexibility of the vehicle. This difficulty has resulted in problems for a multitude of spacecraft including the earliest U.S. spacecraft, Explorer I; the Orbiting Geophysical Observatory III; Mariner 10; Galileo; and the Hubble Telescope. Recognizing the importance of the issue, NASA has an ongoing Controls-Structures Interaction (CSI) technology program to develop the methodology to design optimally and simultaneously both the control system and the structure. The CSI program is a multicenter program involving research teams from NASA's Langley Research Center (LaRC), Jet Propulsion Laboratory (JPL), and Marshall Space Flight Center (MSFC). JPL's area of interest is in optics-class vehicles and MSFC's in astrophysics vehicles. The aim of this paper is to explain the ongoing activities at LaRC, which are of a theoretical, ground test, and flight test nature, with focus on applications to spacecraft with multiple experiment-pointing mounts, large space radiometers, Space Station Freedom (SSF), and the Space Shuttle Remote Manipulator System (RMS).