cssi/SciSciGPT-SciSciNet huggingface dataset:
Schubert Patches Degenerate to Subword Complexes

We study the intersections of general Schubert varieties Xw with permuted big cells, and give an inductive degeneration of each such “Schubert patch” to a Stanley–Reisner scheme. Similar results had been known for Schubert patches in various types of Grassmannians. We maintain reducedness using the results of Knutson [Kn07] on automatically reduced degenerations, or through more standard cohomology-vanishing arguments.
The overlap formalism and topological susceptibility on the lattice

Abstract Recent lattice measurements of the topological susceptibility of SU (2) gauge theory using improved cooling and inverse-blocking are in disagreement. We use the overlap method, which probes the fermionic sector of the theory directly, to help resolve this discrepancy.
Packet routing and selection on the POPS network

Partitioned optical passive stars (POPS) network has been proposed recently as a desirable model of parallel computing. Many papers have been published that address fundamental problems on these networks. Packet routing is one such important problem. We present a randomized algorithm in this paper that performs better than the best prior algorithms. We also present a randomized algorithm for selection on the POPS network.
Complex equiangular tight frames and erasures

In this paper we demonstrate that there are distinct dierences between real and complex equiangular tight frames (ETFs) with regards to erasures. For example, we prove that there exist arbitrarily large non-trivial complex equiangular tight frames which are robust against three erasures, and that such frames come from a unique class of complex ETFs. In addition, we extend certain results in [1] to complex vector spaces as well as show that other results regarding real ETFs are not valid for complex ETFs.
The role of partial and best matches in knowledge systems

Partial matching is a comparison of two or more descriptions that identifies their similarities. Determining which of several descriptions is most similar to one description of interest is called the best match problem. Partial and best matches underlie several knowledge system functions, including: analogical reasoning, inductive inference, predicate discovery, pattern-directed inference, semantic interpretation, and speech and image understanding. Because partial matching is both combinatorial and ill-structured, admissible algorithms are elusive. Economical solutions require very effective use of constraints that, apparently, can be provided only by globally organized knowledge bases. Examples of such organizations are provided, and promising avenues of research are proposed.
Steady state solution of the Fokker-Planck equation combined with unidirectional quasilinear diffusion under detailed balance conditions

Abstract The collisional Fokker-Planck equation combined with an externally imposed quasilinear rf-diffusion is solved for energetic electrons under conditions of detailed balance. The detailed balance condition restricts the functional form of the quasilinear diffusion coefficient. This restriction is tightly related to the simultaneous flattening and broadening of the distribution function in the directions parallel and perpendicular to the magnetic field respectively.
Detection and Tracking of Subtle Cloud Features on Uranus

The recently updated Uranus zonal wind profile (Sromovsky et al.) samples latitudes from 71° S to 73° N. But many latitudes remain grossly undersampled (outside 20°-45° S and 20°-50° N) due to a lack of trackable cloud features. Offering some hope of filling these gaps is our recent discovery of low-contrast cloud that can be revealed by imaging at much higher signal-to-noise ratios (S/Ns) than previously obtained. This is demonstrated using an average of 2007 Keck II NIRC2 near-IR observations. Eleven one-minute H-band exposures, acquired over a 1.6 hr time span, were rectilinearly remapped and zonally shifted to account for planetary rotation. This increased the S/N by about a factor of 3.3. A new fine structure in latitude bands appeared, small previously unobservable cloud tracers became discernible, and some faint cloud features became prominent. While we could produce one such high-quality average, we could not produce enough to actually track the newly revealed features. This requires a specially designed observational effort. We have designed recent Hubble Space Telescope WFC3 F845M observations to allow application of the technique. We measured eight zonal winds by tracking features in these images and found that several fall off of the current zonal wind profile of Sromovsky et al., and are consistent with a partial reversal of their hemispherically asymmetric profile.
Markov Bases of Binary Graph Models

This paper is concerned with the topological invariant of a graph given by the maximum degree of a Markov basis element for the corresponding graph model for binary contingency tables. We describe a degree four Markov basis for the model when the underlying graph is a cycle and generalize this result to the complete bipartite graph K 2,n . We also give a combinatorial classification of degree two and three Markov basis moves as well as a Buchberger-free algorithm to compute moves of arbitrary given degree. Finally, we compute the algebraic degree of the model when the underlying graph is a forest.
Modeling luminosity-dependent galaxy clustering through cosmic time

We employ high-resolution dissipationless simulations of the concordance ΛCDM cosmology (Ω0 = 1 - ΩΛ = 0.3, h = 0.7, σ8 = 0.9) to model the observed luminosity dependence and evolution of galaxy clustering through most of the age of the universe, from z ~ 5 to z ~ 0. We use a simple, nonparametric model, which monotonically relates galaxy luminosities to the maximum circular velocity of dark matter halos (Vmax) by preserving the observed galaxy luminosity function in order to match the halos in simulations with observed galaxies. The novel feature of the model is the use of the maximum circular velocity at the time of accretion, V, for subhalos, the halos located within virial regions of larger halos. We argue that for subhalos in dissipationless simulations, V reflects the luminosity and stellar mass of the associated galaxies better than the circular velocity at the epoch of observation, V. The simulations and our model L-Vmax relation predict the shape, amplitude, and luminosity dependence of the two-point correlation function in excellent agreement with the observed galaxy clustering in the SDSS data at z ~ 0 and in the DEEP2 samples at z ~ 1 over the entire probed range of projected separations, 0.1 < rp/(h-1 Mpc) < 10.0. In particular, the small-scale upturn of the correlation function from the power-law form in the SDSS and DEEP2 luminosity-selected samples is reproduced very well. At z ~ 3-5, our predictions also match the observed shape and amplitude of the angular two-point correlation function of Lyman break galaxies (LBGs) on both large and small scales, including the small-scale upturn. This suggests that, like galaxies in lower redshift samples, the LBGs are fair tracers of the overall halo population and that their luminosity is tightly correlated with the circular velocity (and hence mass) of their dark matter halos.
Stochastic Complexity in Learning

This is an expository paper on the latest results in the theory of stochastic complexity and the associated MDL principle with special interest in modeling problems arising in machine learning. As an illustration we discuss the problem of designing MDL decision trees, which are meant to improve the earlier designs in two ways: First, by use of the sharper formula for the stochastic complexity at the nodes the earlier found tendency of getting too small trees appears to be overcome. Second, a dynamic programming-based pruning algorithm is described for finding the optimal trees, which generalizes an algorithm described in R. Nohre (Ph.D. thesis Linkoping University, 1994).
Global Pattern of Potential Evaporation Calculated from the Penman-Monteith Equation Using Satellite and Assimilated Data

Abstract Potential evaporation has been used to provide a reference level for actual evaporation in many studies of land surface heat and water balance. While Thornthwaite's formula has been used in many regional and global studies, the Penman-Monteith equation has been shown to provide an accurate estimate of this evaporation. Thus, global pattern of potential evaporation has been caleulated from the Penman-Monteith equation using satellite and assimilated data for a 24-month period, January 1987 to December 1988. The albedo and surface resistance have been taken to be, respectively, 0.23 and 70 s m −1 , which are considered to be representative values for actively growing well-watered grass covering the ground. Satellite observations have been used to obtain spatially representative monthly values of solar radiation, fractional cloud cover, air temperature, and vapor pressure, while aerodynamic resistance has been calculated using four-dimensional data assimilation results. Meteorologic data derived from satellite observations are compared with the surface (station) measurements. The calculated potential evaporation values are compared with lysimeter observations for evaporation from well-watered grass at 35 widely distributed locations in different climatic regimes to quantify the accuracy of the calculated values. The evaporation values have been archived for distribution. http://hydro4.gsfc.nasa.gov/STAFF/ChoudhuryBj/pmpotevap.html.
Transonic Navier-Stokes computations for an oscillating wing using zonal grids

Modern jet transports and maneuvering tactical fighters operating in the transonic regime often give rise to time-dependent fluid physics that interact with flexible structural components, e.g., vortical flow, shocks, and separation. Efficient computational fluid dynamic methods are required to study such computationally intensive problems. A numerical method is presented to address this problem. Time-dependent, compressible, NavierStokes equations are used to simulate unsteady transonic flow about a three-dimensional rigid wing undergoing a forced periodic motion in angle of attack. An efficient, implicit, diagonal algorithm is utilized because of its low operation count per time step compared to other methods that solve systems of block matrix equations. The formal time accuracy is theoretically addressed and numerically demonstrated by comparison of computational results with experimental data. A zonal grid approach, capable of treating complex geometries, is presented and its time accuracy is demonstrated by comparing two- and three-zone computations with a single grid computation and experimental data.
Estimating the Uncertainty in Passive-Microwave Rain Retrievals

Current passive-microwave rain-retrieval methods are largely based on databases built off-line using cloud models. The vertical distribution of hydrometeors within the cloud has a large impact on upwelling brightness temperatures. Thus, a forward radiative transfer model can predict off-line the radiance associated with different rain scenarios. To estimate the rain from measured brightness temperatures, one simply looks for the rain scenario whose associated radiances are closest to the measurements. To understand the uncertainties in this process, the authors first study the dependence of the simulated brightness temperatures on different hydrometeor size distribution (DSD) models. They then analyze the marginal and joint distributions of the radiances observed by the Tropical Rainfall Measuring Mission satellite and of those in the databases used in the TRMM rain retrievals. They finally calculate the covariances of the rain profiles and brightness temperatures in the TRMM passive-microwave database and derive a simple parametric model for the conditional uncertainty, given measured radiances. These results are used to characterize the uncertainty inherent in the passive-microwave retrieval.
Technological progress and inequality: an ambiguous relationship

Faster technological change does not necessarily widen wage inequality. This occurs only if technical progress takes the form of product improvements. Conversely, cost-reducing innovation favors a reduction in inequality. This novel result is obtained in a theoretical framework in which individuals can choose both the quality of the equipment and the retooling time. The main implication of this work is that the rapid decline of the durable goods’ price documented in the postwar period, and especially since the 1970s, should have favored areductionin income inequality. The popular view that attributes the rise in inequality to the spread of information technologies is questioned by this analysis.
Methyltestosterone pharmacolinetics and oral bioavailability in rainbow trout (Oncorhynchus mykiss)

Abstract 14 C-methyltestosterone pharmacokinetics after intraarterial (2 and 20 mg/kg) and oral (30 mg/kg) administration were investigated in rainbow trout at 15°C. Plasma concentrations of methyltestosterone were determined by reverse phase high performance liquid chromatography (HPLC) in combination with reverse isotope dilution for upto 6 and 12 days after oral and intraarterial administration, respectively. Methyltestosterone pharmacokinetic parameter values after intraarterial administration were determined using a two compartment model (WinNonlin). For the 2 and 20 mg/kg doses, respectively, the parameter values were, area under the plasma concentration–time curve (11.2 and 82.3 μmol h/l), total body clearance (0.640 and 0.903 l/h per kg), distribution half-life (4.13 and 8.23 h), elimination half-life (54.9 and 58.6 h), volume of the central compartment (3.83 and 13.9 l/kg), volume of distribution at steady state (6.06 and 26.8 l/kg), and the mean residence time (9.57 and 22.7 h). After oral administration, the following parameter values were assessed using a model-independent method, peak concentration (3.03 μmol/l), time of concentration peak (8.80 h), mean absorption time (13.8 h), and area under curve (AUC) 0→∞ (90.2 μmol h/l). A two compartment model analysis of the average plasma concentration–time profile after oral administration showed that absorption followed first-order kinetics with a half-life of 4.7 h. The oral bioavailability of methyltestosterone from food was about 70%.
Effect of Laser Preheating the Workpiece on Micro end Milling of Metals

Micro end milling is a fast and direct method of creating net-shaped functional microparts, micromolds, and prototypes. However, the small flexural stiffness, strength, and hardness of the tool limit the efficiency of machining. It is not expected that a new material with increased hardness and yield strength will be developed in the near future that significantly improves the durability for tools manufactured with diameters in the tens to hundreds of microns. To enable a significant increase in performance and productivity requires higher spindle speeds and increased chiploads. However, an increase in chipload is inhibited by the small flexural stiffness and strength of the tools: a direct result of the tool diameter. Laser-assisted micro end milling has the potential to increase the chipload and productivity by locally reducing the workpiece material's yield strength at the cutting location. This study examines the effect of laser preheating on micro end milling of 6061-T6 aluminum and 1018 steel. Two-flute, 300 μm dia, carbide end mills are used to cut 100 μm deep slots at a spindle speed of 40,000 rpm. The laser power and chipload are varied to show their effect on cutting forces, specific cutting energy, burr formation, surface finish, and temperature. The results are compared to the average material removal temperature given by predictions made from a heat transfer model of the workpiece undergoing laser preheating. Results indicate that chipload and productivity can be significantly increased during dry machining of 6061-T6 aluminum and 1018 steel by localized preheating of the workpiece.
THE PHOTOPHYSICS OF THE CARRIER OF EXTENDED RED EMISSION

Interstellar dust contains a component that reveals its presence by emitting a broad unstructured band of light in the 540-950 nm wavelength range, referred to as extended red emission (ERE). The presence of interstellar dust and ultraviolet photons are two necessary conditions for ERE to occur. This is the basis for suggestions that attribute ERE to an interstellar dust component capable of photoluminescence. In this study, we have collected all published ERE observations with absolute-calibrated spectra for interstellar environments, where the density of ultraviolet photons can be estimated reliably. In each case, we determined the band-integrated ERE intensity, the wavelength of peak emission in the ERE band, and the efficiency with which absorbed ultraviolet photons are contributing to the ERE. The data show that radiation is not only driving the ERE, as expected for a photoluminescence process, but is modifying the ERE carrier, as manifested by a systematic increase in the ERE band's peak wavelength and a general decrease in the photon conversion efficiency with increasing densities of the prevailing exciting radiation. The overall spectral characteristics of the ERE and the observed high quantum efficiency of the ERE process are currently best matched by the recently proposed silicon nanoparticle (SNP) model. Using the experimentally established fact that ionization of semiconductor nanoparticles quenches their photoluminescence, we proceeded to test the SNP model by developing a quantitative model for the excitation and ionization equilibrium of SNPs under interstellar conditions for a wide range of radiation field densities. With a single adjustable parameter, the cross section for photoionization, the model reproduces the observations of ERE intensity and ERE efficiency remarkably well. The assumption that about 50% of the ERE carriers are neutral under radiation conditions encountered in the diffuse interstellar medium leads to a prediction of the single-photon ionization cross section of SNPs with average diameter 3.5 nm of ≤3.4 × 10-15 cm2. The shift of the ERE band's peak wavelength toward larger values with increasing radiation density requires a change of the size distribution of the actively luminescing ERE carriers through a gradual removal of the smaller particles by size-dependent photofragmentation. We propose that heat-assisted Coulomb decay of metastable, multiply charged SNPs is such a process, which selectively removes the smaller components of an existing SNP size distribution.
MBE techniques for IV–VI optoelectronic devices

Abstract Recent development of high-quality IV–VI optoelectronic devices grown by MBE has significantly increased the technological importance of this epitaxial technique in IV–VI materials. Despite the progress made, much is still unknown about the importance of crystal perfection for device performance. Criteria for crystal perfection required to minimize carrier recombination and optical losses in i.r. devices in IV–VI materials need to be established. In this paper the literature on IV–VI film growth by vacuum deposition techniques is briefly reviewed. MBE techniques used for growth of IV–VI materials on BaF 2 and SrF 2 substrates and for growth of PbSnTe on PbTe substrates are described. Emphasis is on the techniques used to deposit pseudobinary alloys with homogeneous composition. The use of foreign impurity dopants is also discussed. Criteria of quality and crystal perfection of epitaxial layers needed for device performance are evaluated. In layers grown on IV–VI substrates, large dislocation densities due to lattice mismatch are normally present but may not be detrimental to device performance. Lattice-matched heteroepitaxial system are discussed. For insulating substrates, it is shown that the crystalline quality and the carrier mobility of layers grown on BaF 2 and SrF 2 are superior to those grown on alkali halide substrates and that the latter are unsuitable for making devices. Carrier mobility is not a good test of crystalline perfection, however, it is argued that device performance, particularly in the demanding requirements for low-noise photodiodes, is a sensitive measure of the epitaxial material quality. Thin-film photodiodes grown by MBE and the hot-wall techniques are then reviewed in detail, including some recent unconventional devices in which the unique properties of thin films are exploited. Heterostructure optical waveguides are described briefly followed by a review of diode laser results obtained by MBE and the hot-wall technique. These results are for thin-film PbTe lasers grown on BaF 2 and for a variety of devices grown on I–VI substrates including single heterostructure, double heterostructure, homostructure, and distributed feedback lasers.
A turbo-coded multiple-description system for multiple antennas

We propose a joint source-channel coding scheme for wireless communication systems with multiple transmit and receive antennas. The source coder is realized by a multiple description encoder that generates multiple bit streams. Each description is then separately turbo coded and transmitted using multiple antennas. For the receiver, we describe a suitable iterative joint source-channel decoding technique that exploits the correlations between the descriptions. We present several examples that illustrate the performance of the proposed system, and compare it with other approaches.
A simple proof that rational curves on K3 are nodal

The Picard group of S is generated by two effective divisors C and F with C = −2, F 2 = 0 and C · F = 1. It can be realized as an elliptic fibration over P with a unique section C, fibers F and λ = 2. Here λ = c1(π∗ω) is the first Chern class of the Hodge bundle π∗ω of the fibration π : S → P (see [H-M]). It is a standard result that the number of nodal fibers of an elliptic fibration are given by 12λ [H-M, p. 158]. So there are exactly 24 rational nodal curves in the linear series |F | for S general. This is the same special K3 surface used by Bryan and Leung in their counting of curves on K3 surfaces [B-L]. It is actually the attempt to understand their method that leads us to our proof. We will call a K3 surface with Picard lattice (1.1) a BL K3 surface. A BL K3 surface S lies on the boundary of the moduli space of K3 surfaces of genus g with C+gF as the corresponding primitive divisor. Every curve in the linear series |OS(C + gF )| is “totally reducible”, i.e., it consists of the −2 curve C and g elliptic “tails” attached to C. A curve D ∈ |OS(C + gF )| is the image of a stable rational map only if D = C ∪m1F1∪m2F2∪ ...∪m24F24, where F1, F2, ..., F24 are 24
Practical implementation issues for active control of large flexible structures

The effect of quantization due to the finite wordlength of microprocessors, analog-to-digital, and digital-to-analog converters, on the desired control law for large flexible structures is investigated. Additionally, the practical effect of actuator dynamics on the stability and performance of the control law is addressed. Finally, an active control experiment is reported which takes into account and demonstrates some of the previously discussed practical considerations.
Repeat-pass multi-temporal interferometric SAR coherence variations with Amazon floodplain and lake habitats

We have analysed interferometric coherence variations in Japanese Earth Resources Satellite (JERS-1) L-band synthetic aperture radar (SAR) data at three central Amazon sites: Lake Balbina, Cabaliana and Solimoes-Purus. Because radar pulse interactions with inundated vegetation typically follow a double-bounce travel path that returns energy to the antenna, coherence will vary with vegetation type as well as with physical and temporal baselines. Lake Balbina consists mostly of upland forests and inundated trunks of dead, leafless trees whereas Cabaliana and Solimoes-Purus are dominated by flooded forests. Balbina has higher coherence values than either Cabaliana or Solimoes-Purus probably because the dead, leafless trees support strong double-bounce returns. The mean coherences of flooded woodland are 0.28 in Balbina and 0.11 in both Cabaliana and Solimoes-Purus. With increasing temporal baselines, flooded and nonflooded wetland habitats show a steadily decreasing trend in coherence values whereas terra-firme and especially open-water habitats have little variation and remain lower in value. Flooded and nonflooded wetland coherence varies with the season whereas terra-firme and open water do not have similarly evident seasonal variations. For example, flooded habitats in all three study regions show annual peaks in coherence values that are typically 0.02 greater than coherence values from temporal baselines 180 days later, yet open water shows no variation with time. Our findings suggest that, despite overall low coherence values, repeat-pass interferometric coherence of flooded habitats is capable of showing the annual periodicity of the Amazon flood wave.
Smart-skin structures for identifying and locating laser irradiation

We have developed a mathematical model of a technique in which a pyramidal arrangement of wavelength-selective optical detectors can be used to determine the identity (wavelength), intensity, and direction of arrival of laser irradiation. The advantages of this technique are that only unobtrusive, skin-like structures are required and that the large collection areas provide high sensitivity. The disadvantage is that the angular resolution (approximately 5 degrees in a 60 degree field of view) is less than that which can be achieved using methods requiring thicker structures. The detector elements are large-area, polyvinylidine fluoride, pyroelectric devices with wavelength selective coatings. We situated four identical arrays of these elements on the top and sides of a frustrated, three-sided prism. Because only the relative orientations are significant, we are able to use selected regions on the surface of an existing structure in an application of this work. Our efforts included developing the mathematical description of the system and, using coated detectors whose performance was experimentally verified, modeling the response to in-channel, monochromatic radiation. Although we limited our model to a simple, two-channel system, the concept and algorithm can easily be extended to a system of any reasonable number of nonoverlapping channels.
Countering GATTACA: efficient and secure testing of fully-sequenced human genomes

Recent advances in DNA sequencing technologies have put ubiquitous availability of fully sequenced human genomes within reach. It is no longer hard to imagine the day when everyone will have the means to obtain and store one's own DNA sequence. Widespread and affordable availability of fully sequenced genomes immediately opens up important opportunities in a number of health-related fields. In particular, common genomic applications and tests performed in vitro today will soon be conducted computationally, using digitized genomes. New applications will be developed as genome-enabled medicine becomes increasingly preventive and personalized. However, this progress also prompts significant privacy challenges associated with potential loss, theft, or misuse of genomic data. In this paper, we begin to address genomic privacy by focusing on three important applications: Paternity Tests, Personalized Medicine, and Genetic Compatibility Tests. After carefully analyzing these applications and their privacy requirements, we propose a set of efficient techniques based on private set operations. This allows us to implement in in silico some operations that are currently performed via in vitro methods, in a secure fashion. Experimental results demonstrate that proposed techniques are both feasible and practical today.
Efficiency tests of options on Treasury bond futures contracts at the Chicago Board of Trade

Abstract This study is an ex-ante and ex-post test of market efficiency for the options on Treasury bond futures contracts traded on the Chicago Board of Trade. All options and futures contracts price changes were examined from market inception, in October, 1982, through the middle of June, 1983 for violations of put-call parity and long box spread arbitrage opportunities. Out of 81,338 option price changes, 891 changes provided expost arbitrage opportunities with average ex-ante profits of $54 per trade for put-call parity strategies and $117 per trade for long box spread strategies. Ex-ante profit opportunities were largest in the early months of trading and had almost disappeared by June, 1983.
ION AND NEUTRAL MOLECULES IN THE W43-MM1(G30.79 FIR 10) INFALLING CLUMP

The high-mass star-forming clump W43-MM1 has been mapped in N2H+(4 → 3), C18O(3 → 2), SiO(8 → 7), and in a single pointing in DCO+(5 → 4) toward the center of the clump. Column densities from these observations as well as previous HCO+(4 → 3), H13CO+(4 → 3), HCN(4 → 3), H13CN(4 → 3), and CS(7 → 6) data have been derived using the RADEX code; results later have been used to derive chemical abundances at selected points in the MM1 main axis. We compare with chemical models to estimate an evolutionary age of 104 years for a remarkable warm hot core inside MM1. We also proposed that the dust temperature derived from the spectral energy distribution fitting in MM1 is not representative of the gas temperature deep inside the clump because dust emission may have become optically thick. By deriving a deuterium fractionation of 1.2 × 103, we estimate an electron fraction of X(e) = 6.5 × 10–8. Thus, the coupling between the neutral gas and the magnetic field is estimated by computing the ambipolar diffusion Reynolds number Rm = 18 and the wave coupling number W = 110. Considering that the infalling speed is slightly supersonic (M = 1.1) but sub-Alfvenic, we conclude that the MM1 clump has recently been or is in the process of decoupling the field from the neutral fluid. Thus, the MM1 clump appears to be in an intermediate stage of evolution in which a hot core has developed while the envelope is still infalling and not fully decoupled from the ambient magnetic field.
Social network intelligence analysis to combat street gang violence

In this paper we introduce the Organization, Relationship, and Contact Analyzer (ORCA) that is designed to aide intelligence analysis for law enforcement operations against violent street gangs. ORCA is designed to address several police analytical needs concerning street gangs using new techniques in social network analysis. Specifically, it can determine "degree of membership" for individuals who do not admit to membership in a street gang, quickly identify sets of influential individuals (under the tipping model), and identify criminal ecosystems by decomposing gangs into sub-groups. We describe this software and the design decisions considered in building an intelligence analysis tool created specifically for countering violent street gangs as well as provide results based on conducting analysis on real-world police data provided by a major American metropolitan police department who is partnering with us and currently deploying this system for real-world use.
Dehydrogenation of a combined LiAlH4/LiNH2 system.

Although there have been numerous materials systems studied as potential candidates for hydrogen storage applications, none of the materials known to date has demonstrated enough hydrogen capacity or efficiency at required operating temperature ranges. There are still considerable opportunities for discovery of new materials or material systems that could lead to advances in science as well as commercial technologies in this area. LiAlH4 is one of the most promising materials owing to its high hydrogen content. In the present work, we investigated dehydrogenation properties of the combined system of LiAlH4 and LiNH2 under atmospheric argon. Thermogravimetric analysis (TGA) of 2LiAlH4/LiNH2 mixtures without any catalysts indicated that a large amount of hydrogen (∼8.1 wt %) can be released between 85 and 320 °C under a heating rate of 2 °C/min in three dehydrogenation reaction steps. It is found that LiNH2 effectively destabilizes LiAlH4 by reacting with LiH during the dehydrogenation process of LiAlH4.
Breaking the Degeneracies between Cosmology and Galaxy Bias

Adopting the framework of the halo occupation distribution (HOD), we investigate the ability of galaxy clustering measurements to simultaneously constrain cosmological parameters and galaxy bias. Starting with a fiducial cosmological model and galaxy HOD, we calculate spatial clustering observables on a range of length and mass scales, dynamical clustering observables that depend on galaxy peculiar velocities, and the galaxy-matter cross-correlation measurable by weak lensing. We then change one or more cosmological parameters and use χ2 minimization to find the galaxy HOD that best reproduces the original clustering. Our parameterization of the HOD incorporates a flexible relation between galaxy occupation numbers and halo mass and allows spatial and velocity bias of galaxies within dark matter halos. Despite this flexibility, we find that changes to the HOD cannot mask substantial changes to the matter density Ωm, the matter clustering amplitude σ8, or the shape parameter Γ of the linear matter power spectrum: cosmology and bias are not degenerate. With the conservative assumption of 10% fractional errors, the set of observables considered here can provide ~10% (1 σ) constraints on σ8, Ωm, and Γ, using galaxy clustering data alone. The combination σ8Ω is constrained to ~5%. In combination with traditional methods that focus on large-scale structure in the "perturbative" regime, HOD modeling can greatly amplify the cosmological power of galaxy redshift surveys by taking advantage of high-precision clustering measurements at small and intermediate scales (from sub-Mpc to ~20 h-1 Mpc). At the same time, the inferred constraints on the galaxy HOD provide valuable tests of galaxy formation theory.
Real Fields and Repeated Radical Extensions

The main result of this paper is that if E is a field extension of finite odd degree over a real field Q, and if E is a repeated radical extension of Q, then every intermediate field is also a repeated radical extension of Q. This paper also contains a number of other results about repeated radical extensions.
Constructing subdivision rules from rational maps

This paper deepens the connections between critically finite rational maps and finite subdivision rules. The main theorem is that if f is a critically finite rational map with no periodic critical points, then for any sufficiently large integer n the iterate f is the subdivision map of a finite subdivision rule. We are interested here in connections between finite subdivision rules and rational maps. Finite subdivision rules arose out of our attempt to resolve Cannon’s Conjecture: If G is a Gromov-hyperbolic group whose space at infinity is a 2-sphere, then G has a cocompact, properly discontinuous, isometric action on hyperbolic 3-space. Cannon’s Conjecture can be reduced (see, for example, the Cannon-Swenson paper [5]) to a conjecture about (combinatorial) conformality for the action of such a group G on its space at infinity, and finite subdivision rules were developed to give models for the action of a Gromov-hyperbolic group on the 2-sphere at infinity. There is also a connection between finite subdivision rules and rational maps. If R is an orientation-preserving finite subdivision rule such that the subdivision complex SR is a 2-sphere, then the subdivision map σR is a critically finite branched map of this 2-sphere. In joint work [3] with Kenyon we consider these subdivision maps under the additional hypotheses that R has bounded valence (this is equivalent to its not having periodic critical points) and mesh approaching 0. In [3, Theorem 3.1] we show that if R is conformal (in the combinatorial sense) then the subdivision map σR is equivalent to a rational map. The converse follows from [4, Theorem 4.7]. In this paper we consider the problem of when a rational map f can be equivalent to the subdivision map of a finite subdivision rule. Since a subdivision complex has only finitely many vertices, such a rational map must be critically finite. We specialize here to the case that f has no periodic critical points. Our main theorem, which has also been proved by Bonk and Meyer [1] when f has a hyperbolic orbifold (which includes all but some well-understood examples), is the following: Date: March 15, 2007. 2000 Mathematics Subject Classification. Primary 37F10, 52C20; Secondary 57M12.
IT Issues for the Management of High-Quantity, Low-Cost Assets

Transportation infrastructure asset management efforts have historically focused on collecting data on assets with high capital costs, such as bridges and pavements. Road signs and pavement markings, on the other hand, are high quantity, low capital cost assets but are also critical elements of the transportation infrastructure. These high quantity assets serve a critical function, safety, and thus they are receiving attention. Mandated by law, the Federal Highway Administration has been working to establish minimum retroreflectivity standards for signs and pavement markings. This paper seeks to address the information technology (IT) problems that emerge when developing an overall asset management system for high-quantity, low-cost assets. These IT problems include asset identification, asset location, data availability, data fragmentation, and automated data collection. A discussion of the issues related to these problems is presented to promote awareness of the myriad problems that do exist and to facilitate the development of more comprehensive systems to manage the automation of infrastructure asset management systems.
HINODE X-RAY TELESCOPE DETECTION OF HOT EMISSION FROM QUIESCENT ACTIVE REGIONS: A NANOFLARE SIGNATURE?

The X-Ray Telescope (XRT) on the Japanese/USA/UK Hinode (Solar-B) spacecraft has detected emission from a quiescent active region core that is consistent with nanoflare heating. The fluxes from 10 broadband X-ray filters and filter combinations were used to construct differential emission measure (DEM) curves. In addition to the expected active region peak at log T = 6.3-6.5, we find a high-temperature component with significant emission measure at log T > 7.0. This emission measure is weak compared to the main peak—the DEM is down by almost three orders of magnitude—which accounts of the fact that it has not been observed with earlier instruments. It is also consistent with spectra of quiescent active regions: no Fe XIX lines are observed in a CHIANTI synthetic spectrum generated using the XRT DEM distribution. The DEM result is successfully reproduced with a simple two-component nanoflare model.
Non-group-theoretical semisimple Hopf algebras from group actions on fusion categories

Given an action of a finite group G on a fusion category \({\mathcal{C}}\) we give a criterion for the category of G-equivariant objects in \({\mathcal{C}}\) to be group-theoretical, i.e., to be categorically Morita equivalent to a category of group-graded vector spaces. We use this criterion to answer affirmatively the question about existence of non-group-theoretical semisimple Hopf algebras asked by P. Etingof, V. Ostrik, and the author in [7]. Namely, we show that certain \({\mathbb{Z}}\)/2\({\mathbb{Z}}\)-equivariantizations of fusion categories constructed by D. Tambara and S. Yamagami [26] are equivalent to representation categories of non-group-theoretical semisimple Hopf algebras. We describe these Hopf algebras as extensions and show that they are upper and lower semisolvable.
AB Aurigae resolved: Evidence for spiral structure

We have obtained high angular resolution (~2'') images of the 13CO (J = 1 → 0) line and 2.7 mm continuum emission and slightly lower resolution images of 12CO (J = 1 → 0) and C18O (J = 1 → 0) line emission toward the Herbig Ae star AB Aurigae. We resolve a circumstellar disk of diameter 780 AU (FWHM) with a velocity pattern consistent with a purely rotational disk at inclination 215 and position angle 586. Using Keplerian disk models, we find a central-source dynamical mass of 2.8 ± 0.1 M☉ and a cutoff radius of 615 AU for the 13CO emission. The inclination, mass, and radius determined from 12CO and C18O observations agree with these values, given optical depth and abundance effects. As a result of the high angular resolution of our observations, we confirm the existence of spiral structure suggested by near-infrared scattered-light images and show that the spiral arms represent density contrasts in the disk.
Diversity of MIMO Linear Precoding

This paper studies multiple-input multiple-output linear precoding in the high-signal-to-noise-ratio regime under flat fading. The diversity at all fixed rates is analyzed for a number of linear precoders. The diversity-multiplexing tradeoffs (DMTs) are also obtained, discovering that for many linear precoders the DMT gives no direct insight into the intricate behavior of fixed-rate diversity. The zero-forcing (ZF), regularized ZF, matched filtering, and Wiener filtering precoders are analyzed. It is shown that regularized ZF (RZF) or matched filter (MF) suffers from error floors for all positive multiplexing gains. However, in the fixed rate regime, RZF and MF precoding achieve full diversity for spectral efficiencies up to a certain threshold and zero diversity at rates above it. When the regularization parameter in the RZF is optimized in the minimum mean square error sense, the structure is known as the Wiener precoder, which in the fixed-rate regime is shown to have diversity that depends not only on the number of antennas, but also on the spectral efficiency. The diversity in the presence of both precoding and equalization is also analyzed.
Information theoretic assessment and design of hyperspectral imaging systems

This paper describes a method for assessing the information density and efficiency of hyperspectral imaging system. The approach computes the information density of the acquired signal as a function of the hyperspectral system design, signal-to-noise ratio, and statistics of the scene radiance. Information efficiency is the ratio of the information density to the data density. The assessment can be used in system design - for example, to optimize information efficiency with respect to the number of spectral bands. Experimental results illustrate that information efficiency exhibits a single distinct maximum as a function of the number of spectral bands, indicating the design with peak information efficiency.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Simulation of Mist Film Cooling on Rotating Gas Turbine Blades

Film cooling technique has been successfully applied to gas turbine blades to prevent it from the hot flue gas. However, a continuous demand of increasing the turbine inlet temperature to raise the efficiency of the turbine requires continuous improvement in film cooling effectiveness. The concept of injecting mist (tiny water droplets) into the cooling fluid has been proven under laboratory conditions to significantly augment adiabatic cooling effectiveness 50-800% in convective heat transfer and impingement cooling. The similar concept of ejecting mist into air film cooling has not been proven in the laboratory, but computational simulation has been performed on stationary turbine blades. As a continuation of previous research, this paper extends the mist film cooling scheme to the rotating turbine blade. For the convenience of understanding the effect of rotation, the simulation is first conducted with a single pair of cooling hole located near the leading edge at either side of the blade. Then a row of multiplehole film cooling jets are simulated at stationary and rotational condition. Operating condition under both the laboratory (baseline) and elevated gas turbine conditions are simulated and compared. The effects of various parameters including mist concentration, water droplet diameter, droplet wall boundary condition, blowing ratio, and rotational speed are investigated. The results showed the effect of rotation on droplets at lab condition is minimal. The CFD model employed the Discrete Phase Model (DPM) including both wall film and droplet reflect conditions. The results showed that the droplet-wall interaction is stronger on the pressure side than on the suction side resulting in a higher mist cooling enhancement on the pressure side. The average mist cooling enhancement of about 15% and 35% are achieved on the laboratory and elevated conditions, respectively. This translates into a significant blade surface temperature reduction of 100125 K with 10% mist injection at elevated condition.
Gravitational Recoil from Spinning Binary Black Hole Mergers

The inspiraling and merger of binary black holes will likely involve black holes with not only unequal masses but also arbitrary spins. The gravitational radiation emitted by these binaries will carry angular as well as linear momentum. A net flux of emitted linear momentum implies that the black hole produced by the merger will experience a recoil or kick. Previous studies have focused on the recoil velocity from unequal-mass, nonspinning binaries. We present results from simulations of equal-mass but spinning black hole binaries and show how a significant gravitational recoil can also be obtained in these situations. We consider the case of black holes with opposite spins of magnitude a aligned and antialigned with the orbital angular momentum, with a the dimensionless spin parameter of the individual holes. For the initial setups under consideration, we find a recoil velocity of V = 475a km s-1. Supermassive black hole mergers producing kicks of this magnitude could result in the ejection of the final hole produced by the collision from the core of a dwarf galaxy.
Solvable number field extensions of bounded root discriminant

Let $K$ be a number field and $d_K$ the absolute value of the discrimant of $K/\mathbb{Q}$. We consider the root discriminant $d_L^{\frac{1}{[L:\mathbb{Q}]}}$ of extensions $L/K$. We show that for any $N>0$ and any positive integer n, the set of length n solvable extensions of $K$ with root discriminant less than $N$ is finite. The result is motivated by the study of class field towers.
The financing threshold effect on success and failure of biomedical and pharmaceutical start-ups

The theories of technological innovation are examined in the context of the formation and growth of biomedical and pharmaceutical firms. Analyses are based on detailed data gathered from 26 firms, founded between 1968 and 1975 in Massachusetts, supplemented by a three-member expert panel evaluation of the risk associated with use of each firm's products. A positive relationship was established between the level of technological sophistication of the firm and the risk associated with use of its products. Consequently, technological advancement of the firm has not necessarily resulted in high economic performance, in part because of the high demands put upon the firm's resources and time by the U.S. Food and Drug Administration approval process. The study indicates that the initial financial inputs have a threshold effect on subsequent economic performance of biomedical and pharmaceutical new firms. In the sample studied, unless these inputs reached the $850,000 to $1,000,000 mark in 1970-1975 dollars, technological innovation was negatively mediated by the risk associated with the use of firm's products and by the FDA quality control procedures. Consequently, attempts at technological innovativeness are unfortunately detrimental to the economic performance of underfinanced new firms in the biomedical and pharmaceutical industry.