cssi/SciSciGPT-SciSciNet huggingface dataset:
Pressure, Temperature, and Velocity Measurements in Underexpanded Jets Using Laser-Induced Fluorescence Imaging

We report measurements of pressure, temperature, and velocity in an underexpanded jet using planar laser-induced fluorescence of nitric oxide. Ultraviolet transitions near 44, 097.5 cm -1 in the A-X (0,0) system of nitric oxide were excited using narrow linewidth laser radiation generated from an optical parametric system, injection seeded using a distributed feedback diode laser. Planar laser-induced fluorescence images with excellent spatial resolution and signal-to-noise ratio were acquired by tuning the frequency of the laser radiation over the nitric oxide absorption line. The images were corrected on a shot-to-shot basis for fluctuations in the laser spatial profile. Line shapes constructed from the corrected planar laser-induced fluorescence images were used to determine pressure and temperature values along the centerline of the jet. Good agreement between laser-induced fluorescence and previously reported N 2 coherent anti-Stokes Raman scattering measurements was observed. The laser-induced fluorescence measurements also compared well with calculations of pressure and temperature using computational fluid dynamics codes. Velocity was measured in supersonic regions of the flowfield on the basis of the Doppler shift in the nitric oxide absorption lines. Planar laser-induced fluorescence images were acquired using laser sheets propagating at 90 and 45 degrees with respect to the flow direction; velocity was determined from the frequency shift of the absorption lines for these two shifts. The laser-induced fluorescence technique can potentially be applied to obtain instantaneous measurements of thermodynamic properties and multiple velocity components in high-speed turbulent flows.
Europa's opposition surge in the near-infrared: interpreting disk-integrated observations by Cassini VIMS

Abstract Near-infrared observations of Europa's disk-integrated opposition surge by Cassini VIMS, first published in Fig. 4 of Brown et al. (2003, Icarus, 164, 461), have now been modeled with the commonly used Hapke photometric function. The VIMS data set emphasizes observations at 16 solar phase angles from 0.4° to 0.6°—the first time the 1 ° phase “heart” of Europa's opposition surge has been observed this well in the near-IR. This data set also provides a unique opportunity to examine how the surge is affected by changes in wavelength and albedo: at VIMS wavelengths of 0.91, 1.73, and 2.25 μm, the geometric albedo of Europa is 0.81, 0.33, and 0.18, respectively. Despite this factor-of-four albedo range, however, the slope of Europa's phase curve at 1 ° phase is similar at all three wavelengths (to within the error bars) and this common slope is similar to the phase coefficient seen in visible-light observations of Europa. The two components of the opposition surge—involving different models of the physical cause of the surge—are the Shadow Hiding Opposition Effect (SHOE) and the Coherent Backscatter Opposition Effect (CBOE). Because of sparse VIMS phase coverage, it is not possible to constrain all the surge parameters at once in a Hapke function that has both SHOE and CBOE; accordingly, we performed separate Hapke fits for SHOE-only and CBOE-only surges. At 2.25 μm, where VIMS data are somewhat noisy, both types of surges can mimic the slope of the VIMS phase curve at 1 ° phase. At 0.91 and 1.73 μm, however—where VIMS data are “cleaner”—CBOE does a noticeably poorer job than SHOE of matching the VIMS phase coefficient at 1 ° phase; in particular, the best CBOE fit insists on having a steeper phase-curve slope than the data. This discrepancy suggests that Europa's near-IR opposition surge cannot be explained by CBOE alone and must have a significant SHOE component, even at wavelengths where Europa is bright.
Compressive Creep Testing of Thermal Barrier Coated Nickel-Based Superalloys

Turbine airfoils have complex geometries and, during service operation, are subjected to complex loadings. In most publications, results are typically reported for either uniaxial, isothermal tensile creep or for thermal cyclic tests. The former generally provides data for creep of the superalloy and the overall performance, and the later provide data for thermal barrier coating (TBC) spallation as a function of thermally grown oxide thickness, surface roughness, temperature, and thermal mismatch between the layers. Both tests provide valuable data but little is known about the effect of compressive creep strain on the performance of the superalloy/protective system at elevated temperatures. In conjunction with computational model development, laboratory-scale experimental validation was undertaken to verify the viability of the underlying damage mechanics concepts for the evolution of TBC damage. Nickel-based single crystal Rene N5 coupons that were coated with a ∼150–200 μm MCrAlY bond coat and a ∼200–240 μm 7-YSZ APS top coat were used in this effort. The coupons were exposed to 900°C, 1000°C, and 1100°C, for periods of 100 h, 300 h, 1000 h, and 3000 h in slotted silicon carbide fixtures. The difference in the coefficients of thermal expansion of the Rene N5 substrate and the test fixture introduces thermally induced compressive stress in the coupon samples. Exposed samples were cross sectioned and evaluated using scanning electron microscopy. Performance data were collected based on image analysis. Energy-dispersive X-ray was employed to study the elemental distribution in the TBC system after exposure. To better understand the loading and failure mechanisms of the coating system under loading conditions, nanoindentation was used to study the mechanical properties (Young’s modulus and hardness) of the components in the TBC system and their evolution with temperature and time. The effect of uniaxial in-plane compressive creep strain on the rate of growth of the thermally grown oxide layer, the time to coating failure in TBC systems, and the evolution in the mechanical properties are presented.
Ceramic technology for solar thermal receivers

Development of ceramic receiver technology for advanced solar thermal energy applications is being pursued in order to achieve significant reductions in energy cost and increase the potential application of solar thermal energy. Basically, structural ceramics are being seriously considered for solar applications because of their high temperature capability, their nonstrategic nature, and their potential for low cost. In this paper, candidate ceramic materials for solar receivers and their characteristics are described, potentially applicable fabrication and processing methods are discussed, and their applicability and promise for solar receivers is assessed. Receiver design requirements as well as system requirements for solar applications are reviewed. Promising areas of application of ceramic receivers in the near future are also discussed. Current ceramic receiver development status and plans are described, including one receiver which has been successfully tested at gas exit temperatures of up to 1425/sup 0/C.
The relationship between skew group algebras and orbifold theory

Abstract Let V be a simple vertex operator algebra and let G be a finite automorphism group of V . In [C. Dong, G. Yamskulna, Math. Z., to appear], it was shown that any irreducible V -module is a completely reducible V G -module where V G is the G -invariant vertex operator subalgebra of V . In this paper, we give an alternative proof of this fact using the theory of skew group algebras. We also extend this result to any irreducible g -twisted V -module when g is in the center of G and V is a g -rational vertex operator algebra.
THE MASS OF THE BLACK HOLE IN THE QUASAR PG 2130+099

We present the results of a recent reverberation-mapping campaign undertaken to improve measurements of the radius of the broad-line region and the central black hole mass of the quasar PG 2130+099. Cross-correlation of the 5100 A continuum and Hβ emission-line light curves yields a time lag of 22.9−4.3+4.4 days, corresponding to a central black hole mass MBH = (3.8 ± 1.5) × 107 M☉. This value supports the notion that previous measurements yielded an incorrect lag. We reanalyze previous data sets to investigate the possible sources of the discrepancy and conclude that previous measurement errors were apparently caused by a combination of undersampling of the light curves and long-term secular changes in the Hβ emission-line equivalent width. With our new measurements, PG 2130+099 is no longer an outlier in either the RBLR-L or the MBH-σ* relationship.
Liftings and quasi-liftings of DG modules

Abstract We prove lifting results for DG modules that are akin to Auslander, Ding, and Solbergʼs famous lifting results for modules.
A Scalable Middleware for Web Databases

The emergence of Web databases has introduced new challenges related to their organization, access, integration, and interoperability. New approaches and techniques are needed to provide across-the-board transparency for accessing and manipulating Web databases irrespective of their data models, platforms, locations, or systems. In meeting these needs, it is necessary to build a middleware infrastructure to support flexible tools for information space organiza­tion, communication facilities, information discovery, content description, and assembly of data from heterogeneous sources. In this paper, we describe a scalable middleware for efficient data and application access that we have built using the available technologies. The resulting system is called WebFINDIT. It is a scalable and uniform infrastructure for locating and accessing heterogeneous and autonomous databases and applications.
CREDIT RATIONING AND BLACK-OWNED FIRMS: IS THERE EVIDENCE OF DISCRIMINATION?

This article uses data from the 2003 Survey of Small Business Finances to determine if banks ration credit more severely to black-owned firms. Our results reveal this is the case. Using the Heckman two-step procedure, we determined that black- and white-owned firms have a comparable demand for credit as measured by their actual use of lines of credit. Controlling for firm and owner characteristics, however, black-owned firms had lower line of credit limits suggesting constraints in supply. Further, our findings suggest the supply of credit to black-owned firms is even more severely constrained than other minority-owned firms. These findings highlight the possibility of discrimination against black-owned firms in the form of credit rationing.
Multilinear embedding – convolution estimates on smooth submanifolds

Multilinear embedding estimates for the fractional Laplacian are obtained in terms of functionals defined over a hyperbolic surface. Convolution estimates used in the proof enlarge the classical framework of the convolution algebra for Riesz potentials to include the critical endpoint index, and provide new realizations for fractional integral inequalities that incorporate restriction to smooth submanifolds. Results developed here are modeled on the space-time estimate used by Klainerman and Machedon in their proof of uniqueness for the Gross-Pitaevskii hierarchy.
The Role of Nucleosome Positioning in the Evolution of Gene Regulation

Chromatin organization plays a major role in gene regulation and can affect the function and evolution of new transcriptional programs. However, it can be difficult to decipher the basis of changes in chromatin organization and their functional effect on gene expression. Here, we present a large-scale comparative genomic analysis of the relationship between chromatin organization and gene expression, by measuring mRNA abundance and nucleosome positions genome-wide in 12 Hemiascomycota yeast species. We found substantial conservation of global and functional chromatin organization in all species, including prominent nucleosome-free regions (NFRs) at gene promoters, and distinct chromatin architecture in growth and stress genes. Chromatin organization has also substantially diverged in both global quantitative features, such as spacing between adjacent nucleosomes, and in functional groups of genes. Expression levels, intrinsic anti-nucleosomal sequences, and trans-acting chromatin modifiers all play important, complementary, and evolvable roles in determining NFRs. We identify five mechanisms that couple chromatin organization to evolution of gene regulation and have contributed to the evolution of respiro-fermentation and other key systems, including (1) compensatory evolution of alternative modifiers associated with conserved chromatin organization, (2) a gradual transition from constitutive to trans-regulated NFRs, (3) a loss of intrinsic anti-nucleosomal sequences accompanying changes in chromatin organization and gene expression, (4) re-positioning of motifs from NFRs to nucleosome-occluded regions, and (5) the expanded use of NFRs by paralogous activator-repressor pairs. Our study sheds light on the molecular basis of chromatin organization, and on the role of chromatin organization in the evolution of gene regulation.
Asymmetric synthesis of protected 1,2-amino alcohols using tert-butanesulfinyl aldimines and ketimines.

tert-Butanesulfinyl aldimines and ketimines bearing an α-benzyloxy or α-silyloxy substituent serve as precursors in the synthesis of protected 1,2-amino alcohols in high yields and diastereoselectivities. General protocols are described for the addition of unbranched alkyl, branched alkyl, and aryl organometallic reagents to N-sulfinyl aldimines 1 and 2 and ketimines 5 and 6. Furthermore, the selective N- or O-deprotection of sulfinamide products 3, 4, 7, and 8 is described, enabling further synthetic transformations of the reaction products.
Core formation in giant gaseous protoplanets

Abstract Sedimentation rates of silicate grains in gas giant protoplanets formed by disk instability are calculated for protoplanetary masses between 1 M Saturn to 10 M Jupiter . Giant protoplanets with masses of 5 M Jupiter or larger are found to be too hot for grain sedimentation to form a silicate core. Smaller protoplanets are cold enough to allow grain settling and core formation. Grain sedimentation and core formation occur in the low mass protoplanets because of their slow contraction rate and low internal temperature. It is predicted that massive giant planets will not have cores, while smaller planets will have small rocky cores whose masses depend on the planetary mass, the amount of solids within the body, and the disk environment. The protoplanets are found to be too hot to allow the existence of icy grains, and therefore the cores are predicted not to contain any ices. It is suggested that the atmospheres of low mass giant planets are depleted in refractory elements compared with the atmospheres of more massive planets. These predictions provide a test of the disk instability model of gas giant planet formation. The core masses of Jupiter and Saturn were found to be ∼ 0.25 M ⊕ and ∼ 0.5 M ⊕ , respectively. The core masses of Jupiter and Saturn can be substantially larger if planetesimal accretion is included. The final core mass will depend on planetesimal size, the time at which planetesimals are formed, and the size distribution of the material added to the protoplanet. Jupiter's core mass can vary from 2 to 12 M ⊕ . Saturn's core mass is found to be ∼ 8 M ⊕ .
Thermochemistry of Proton-Coupled Electron Transfer Reagents and its Implications

Many, if not most, redox reactions are coupled to proton transfers. This includes most common sources of chemical potential energy, from the bioenergetic processes that power cells to the fossil fuel combustion that powers cars. These proton-coupled electron transfer or PCET processes may involve multiple electrons and multiple protons, as in the 4 e–, 4 H+ reduction of dioxygen (O2) to water (eq 1), or can involve one electron and one proton such as the formation of tyrosyl radicals from tyrosine residues (TyrOH) in enzymatic catalytic cycles (eq 2). In addition, many multi-electron, multi-proton processes proceed in one-electron and one-proton steps. Organic reactions that proceed in one-electron steps involve radical intermediates, which play critical roles in a wide range of chemical, biological, and industrial processes. This broad and diverse class of PCET reactions are central to a great many chemical and biochemical processes, from biological catalysis and energy transduction, to bulk industrial chemical processes, to new approaches to solar energy conversion. PCET is therefore of broad and increasing interest, as illustrated by this issue and a number of other recent reviews.
The Equivalence between Enumerating Cyclically Symmetric, Self-Complementary and Totally Symmetric, Self-Complementary Plane Partitions

We prove that the number of cyclically symmetric, self-complementary plane partitions contained in a cube of side 2nequals the square of the number of totally symmetric, self-complementary plane partitions contained in the same cube, without explicitly evaluating either of these numbers. This appears to be the first direct proof of this fact. The problem of finding such a proof was suggested by Stanley (J. Combin. Theory Ser. A43(1996), 103?113).
The dark side of a patchwork universe

While observational cosmology has recently progressed fast, it revealed a serious dilemma called dark energy: an unknown source of exotic energy with negative pressure driving a current accelerating phase of the universe. All attempts so far to find a convincing theoretical explanation have failed, so that one of the last hopes is the yet to be developed quantum theory of gravity. In this article, loop quantum gravity is considered as a candidate, with an emphasis on properties which might play a role for the dark energy problem. Its basic feature is the discrete structure of space, often associated with quantum theories of gravity on general grounds. This gives rise to well-defined matter Hamiltonian operators and thus sheds light on conceptual questions related to the cosmological constant problem. It also implies typical quantum geometry effects which, from a more phenomenological point of view, may result in dark energy. In particular the latter scenario allows several non-trivial tests which can be made more precise by detailed observations in combination with a quantitative study of numerical quantum gravity. If the speculative possibility of a loop quantum gravitational origin of dark energy turns out to be realized, a program as outlined here will help to hammer out our ideas for a quantum theory of gravity, and at the same time allow predictions for the distant future of our universe.
Uniform asymptotics for the tail probability of weighted sums with heavy tails

Abstract This paper studies the tail probability of weighted sums of the form ∑ i = 1 n c i X i , where random variables X i ’s are either independent or pairwise quasi-asymptotically independent with heavy tails. Using the idea of uniform long-tailedness, the uniform asymptotic equivalence of the tail probabilities of ∑ i = 1 n c i X i , max 1 ≤ k ≤ n ∑ i = 1 k c i X i and ∑ i = 1 n c i X i + is established, where X i ’s are independent and follow the long-tailed distribution, and c i ’s take value in a broad interval. Some further uniform asymptotic results for the weighted sums of X i ’s with dominated varying tails are obtained. An application to the ruin probability in a discrete-time insurance risk model is presented.
The Social Studies Teacher as Writing Coach

Writing isn't just for English class anymore. Since 1973, many state-sponsored writing projects have been instituted in the wake of the Bay Area Writing Project's progressive ideas about the teaching of writing. Teachers across the disciplines have been bombarded with scads of quick fixes and some reasoned curatives designed for the improvement of student writing.1 A major underlying theme in all of the suggested remedies is that writing is knowing-a way not only to improve writing but also to help students improve in a particular subject.2 Teachers and researchers in various fields acknowledge that teaching writing is not solely the English teacher's responsibility. In many schools, English teachers and content-area teachers have pooled their resources to improve writing instruction.3 Alfred J. Ciani, for instance, claims that mathematicians recognize the importance of reading and writing skills for a child's understanding of mathematics.4 The social studies teacher's belief in the total curriculum approach to teaching writing was underscored several years ago by the National Council for the Social Studies's special edition of Social Education devoted to writing in the social studies.5 Teachers in other fields have expressed similar views about the importance of writing across the curriculum.6 Lee Odell has suggested that if writing is to be improved on a grand scale, the teacher must relate "the process of writing to the process of learning a given subject."' Furthermore, a subject-area teacher (such as a social studies teacher) must emphasize the importance of writing in different modes (the expressive and poetic as well as the transactional). For example, in addition to performing transactional writing about Benjamin Franklin (such as a biographical sketch), the social studies teacher might ask the student to write a poem depicting Franklin's feelings about his discoveries or an interpretive essay exploring Franklin's conflict between his religious and scientific be-
The Improvement Program in Nonrelativistic Lattice QCD

Progress in the improvement program in nonrelativistic lattice QCD is outlined. The leading radiative corrections to the heavy-quark mass renormalization, energy shift, and two important kinetic coupling coefficients are presented. The reliability of tadpole-improved perturbation theory in determining the energy shift and mass renormalization is demonstrated.
Recent experiments with Bose-condensed gases at JILA

We consider a binary mixture of two overlapping Bose- Einstein condensates in two different hyperfine states of 87Rb with nearly identical magnetic moments. Such a system has been simply realized through application of radio frequency and microwave radiation which drives a two-photon transition between the two states. The nearly identical magnetic moments afford a high degree of spatial overlap, permitting a variety of new experiments. We discuss some of the conditions under which the magnetic moments are identical, with particular emphasis placed on the requirements for a time-averaged orbiting potential magnetic trap.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
A Fresh Look at Gauge Coupling Unification

The apparent unification of gauge couplings around 1016 GeV is one of the strong arguments in favor of Supersymmetric extensions of the Standard Model (SM). In this contribution a new analysis, using the latest experimental data, is performed. The strong coupling αs emerges as the key factor for evaluating the results of the fits, as the experimental and theoretical uncertainties in its measurements are substantially higher than for the electromagnetic and weak couplings. The present analysis pays special attention to numerical and statistical details. The results, combined with the current limits on the supersymmetric particle masses, favor a value for the SUSY scale ≲ 150 GeV and for αs = 0.118 - 0.119.
Race, Political Empowerment, and Constituency Service: Descriptive Representation and the Hiring of African-American Congressional Staff

Do democratic legislators, African-American legislators, and/or legislators from black-majority districts hire a higher proportion of district staff that are African-American? Legal experts and policymakers are engaged in discussions over the efficacy of districts with significant African-American populations in the wake of the extension of portions of the Voting Rights Act. With the Act's extension, critics have planned to file suit against districts likely to elect African-American legislators, alleging that these districts may harm African-American constituents. In contrast, we argue that these districts may be useful in enhancing African-American political empowerment and that the presence of African-American staff in legislative district offices is an indicator of this empowerment. Based on interviews with staff in 41 congressional district offices, and on quantitative analysis, we find that African-American-majority districts and the presence of African-American and Democratic legislators lead to a higher proportion of African-American district staff. The results suggest that contrary to the conventional wisdom of some voting rights scholars, in the aggregate the election of African-American legislators (and thus the drawing of African-American-majority or influence districts) enhances the empowerment of African-American constituents when based on an examination of African-American district staff and constituency service.
Diffraction of Electromagnetic Waves by a Plane Wire Grating

Previous work on diffraction by a wire grating is briefly reviewed. The problem of diffraction by a finite grating consisting of perfectly conducting wires of arbitrary cross section is formulated in terms of characteristic plane waves corresponding to the various order spectra defined in optics. Scattering matrix elements are expressed as stationary functionals of current distribution on the grating wires, for the incident wave falling at right angles to the grating elements and polarized either parallel or perpendicular to them. These are evaluated for the thin wire grating and parallel polarization.
Lattice Coulomb hamiltonian and static color-Coulomb field

The lattice Coulomb-gauge hamiltonian is derived from the transfer matrix of Wilson's Euclidean lattice gauge theory, wherein the lattice form of Gauss's law is satisfied identically. The restriction to a fundamental modular region (no Gribov copies) is implemented in an effective hamiltonian by the addition of a “horizon function” G to the lattice Coulomb-gauge hamiltonian. Its coefficient γ0 is a thermodynamic parameter that ultimately sets the scale for hadronic mass, and which is related to the bare coupling constant g0 by a “horizon condition”. This condition determines the low momentum behavior of the (ghost) propagator that transmits the instantaneous longitudinal color-electric field, and thereby provides for a confinement-like feature in leading order in a new weak-coupling expansion.
Magnetic field induced ordering in quasi-one-dimensional quantum magnets

Three-dimensional magnetic ordering transitions are studied theoretically in strongly anisotropic quantum magnets. An external magnetic field can drive quasi-one-dimensional subsystems with a spin gap into a gapless regime, thus inducing long-range three-dimensional magnetic ordering due to weak residual magnetic coupling between the subsystems. Compounds with higher spin degrees of freedom, such as N-leg spin-1/2 ladders, are shown to have cascades of ordering transitions. At high magnetic fields, zero-point fluctuations within the quasi-1D subsystems are suppressed, causing quantum corrections to the ordering temperature to be reduced.
Use of combined micro extractor SFC interface and micro Fourier transform infrared spectroscopy for characterization of the low molecular weight fractions of asphalt

ABSTRACT Combining supercritical fluid chromatography and Fourier transform infrared spectroscopy has been described in a number of reports. This work is concerned with developing an automated combined micro Fourier transform infrared spectroscopy with a micro extractor SFC interface. The instrument is described in detail. Basically it consists of a computer driven collector drum complete with cooling assembly that is attached to the exit of an SFC extractor which can be controlled as to temperature and pressure. This permits some preliminary fractionation. The interface is then moved to micro FTIR. The computer then is used to position the collected areas successively under the FTIR and multiple scans are made to any desired level. Examples are given of the performance on extracts from asphalts
THERMAL HISTORIES OF CHONDRULES IN SOLAR NEBULA SHOCKS

Chondrules are important early Solar System materials that can provide a wealth of information on conditions in the solar nebula, if their formation mechanism can be understood. The theory most consistent with observational constraints, especially thermal histories, is the so-called shock model, in which chondrules were melted in solar nebula shocks. However, several problems have been identified with previous shock models. These problems all pertained to the treatment of the radiation field, namely, the input boundary condition to the radiation field, the proper treatment of the opacity of solids, and the proper treatment of molecular line cooling. In this paper, we present the results of our updated shock model, which corrects for the problems listed above. Our new hydrodynamic shock code includes a complete treatment of molecular line cooling due to H{sub 2}O. Previously, shock models including line cooling predicted chondrule cooling rates exceeding 10{sup 5} K hr{sup -1}. Contrary to these expectations, we have found that the effect of line cooling is minimal; after the inclusion of line cooling, the cooling rates of chondrules are 10-1000 K hr{sup -1}. The reduction in the otherwise rapid cooling rates attributable to line cooling is due to a combination of factors, includingmore » buffering due to hydrogen recombination/dissociation, high column densities of water, and backwarming. Our model demonstrates that the shock model for chondrule formation remains consistent with observational constraints.« less
Parameter Estimation in Spherical Symmetry Groups

This letter considers statistical estimation problems where the probability distribution of the observed random variable is invariant with respect to actions of a finite topological group. It is shown that any such distribution must satisfy a restricted finite mixture representation. When specialized to the case of distributions over the sphere that are invariant to the actions of a finite spherical symmetry group ${\cal G}$ , a group-invariant extension of the Von Mises Fisher (VMF) distribution is obtained. The ${\cal G}$ -invariant VMF is parameterized by location and scale parameters that specify the distribution’s mean orientation and its concentration about the mean, respectively. Using the restricted finite mixture representation these parameters can be estimated using an Expectation Maximization (EM) maximum likelihood (ML) estimation algorithm. This is illustrated for the problem of mean crystal orientation estimation under the spherically symmetric group associated with the crystal form, e.g., cubic or octahedral or hexahedral. Simulations and experiments establish the advantages of the extended VMF EM-ML estimator for data acquired by Electron Backscatter Diffraction (EBSD) microscopy of a polycrystalline Nickel alloy sample.
Venous Distensibility in Essential Hypertension

Forearm venous distensibility was measured in patients with essential hypertension and in normotensive subjects in both the horizontal and 60° feet-down positions. The hypertensive patients exhibited a reduced venous distensibility compared with the normal subjects and, furthermore, showed minimal change on being tilted, whereas distensibility decreased 27% in the normal subjects. Treatment of the hypertensives with various antihypertensive drugs increased venous distensibility above pre-treatment values. These findings indicate that a state of increased venomotor tone exists in essential hypertension.
A search for dwarf seyfert nuclei. vi. properties of emission-line nuclei in nearby galaxies

We use the database from Paper III to quantify the global and nuclear properties of emission-line nuclei in the Palomar spectroscopic survey of nearby galaxies. We show that the host galaxies of Seyferts, LINERs, and transition objects share remarkably similar large-scale properties and local environments. The distinguishing traits emerge on nuclear scales. Compared with LINERs, Seyfert nuclei are an order of magnitude more luminous and exhibit higher electron densities and internal extinction. We suggest that Seyfert galaxies possess characteristically more gas-rich circumnuclear regions and hence a more abundant fuel reservoir and plausibly higher accretion rates. The differences between the ionization states of the narrow emission-line regions of Seyferts and LINERs can be partly explained by the differences in their nebular properties. Transition-type objects are consistent with being composite (LINER/H II) systems. With very few exceptions, the stellar population within the central few hundred parsecs of the host galaxies is uniformly old, a finding that presents a serious challenge to starburst or post-starburst models for these objects. Seyferts and LINERs have virtually indistinguishable velocity fields as inferred from their line widths and line asymmetries. Transition nuclei tend to have narrower lines and more ambiguous evidence for line asymmetries. All three classes of objects obey a strong correlation between line width and line luminosity. We argue that the angular momentum content of circumnuclear gas may be an important factor in determining whether a nucleus becomes active. Finally, we discuss some possible complications for the unification model of Seyfert galaxies posed by our observations.
TADPOLE GALAXIES IN THE HUBBLE ULTRA DEEP FIELD

Tadpole galaxies have a head-tail shape with a large clump of star formation at the head and a diffuse tail or streak of stars off to one side. We measured the head and tail masses, ages, surface brightnesses, and sizes for 66 tadpoles in the Hubble Ultra Deep Field (UDF) and looked at the distribution of neighbor densities and tadpole orientations with respect to neighbors. The heads have masses of 107-108 M ☉ and photometric ages of ~0.1 Gyr for z ~ 2. The tails have slightly larger masses than the heads and comparable or slightly older ages. The most obvious interpretation of tadpoles as young merger remnants is difficult to verify. They have no enhanced proximity to other resolved galaxies as a class, and the heads, typically <0.2 kpc in diameter, usually have no obvious double-core structure. Another possibility is ram pressure interaction between a gas-rich galaxy and a diffuse cosmological flow. Ram pressure can trigger star formation on one side of a galaxy disk, giving the tadpole shape when viewed edge-on. Ram pressure can also strip away gas from a galaxy and put it into a tail, which then forms new stars and gravitationally drags along old stars with it. Such an effect might have already been observed in the Virgo Cluster. Another possibility is that tadpoles are edge-on disks with large, off-center clumps. Analogous lop-sided star formation in UDF clump clusters is shown.
The Long Beach public safety information subsystem

Not many years ago, officials in a city with a five year capital improvement plan, a "master" plan, and a computer that handled payroll calculations and utility billing were termed relatively progressive. This was considered a dynamic approach to the use of modern management techniques and computer technology.
Resampling-based empirical prediction: an application to small area estimation

Best linear unbiased prediction is well known for its wide range of applications including small area estimation. While the theory is well established for mixed linear models and under normality of the error and mixing distributions, the literature is sparse for nonlinear mixed models under nonnormality of the error distribution or of the mixing distributions. We develop a resampling-based unified approach for predicting mixed effects under a generalized mixed model set-up. Second-order-accurate nonnegative estimators of mean squared prediction errors are also developed. Given the parametric model, the proposed methodology automatically produces estimators of the small area parameters and their mean squared prediction errors, without requiring explicit analytical expressions for the mean squared prediction errors.
Chemistry and Biology of the Zaragozic Acids (Squalestatins)

New natural products seldom arouse much excitement. However, with their unprecedented and heavily oxygenated molecular structure, and potentially lucrative biological activity, the zaragozic acids (squalestatins) provoked a flurry of activity among academic and industrial chemists and biologists in the early 1990s. Since they are powerful inhibitors of squalene synthase, the enzyme catalyzing the first committed step on the biosynthetic pathway to cholesterol, hopes were high that the zaragozic acids would follow the huge commercial success of the mevinic acids by becoming second-generation cholesterol-lowering drugs. The unusual and characteristic 2,8-dioxabicyclo[3.2.1]octane-3,4,5-tricarboxylic acid “core” structure of the zaragozic acids stimulated a large number of diverse synthetic studies, ranging from the traditional to the avant garde. In this review we attempt to bring together for the first time the chemistry and biology of this fascinating class of molecules.
Generic fiber rings of mixed power series/polynomial rings

Abstract Let K be a field, m and n positive integers, and X = { x 1 , … , x n } , and Y = { y 1 , … , y m } sets of independent variables over K. Let A be the localized polynomial ring K [ X ] ( X ) . We prove that every prime ideal P in A ˆ = K 〚 X 〛 that is maximal with respect to P ∩ A = ( 0 ) has height n − 1 . We consider the mixed power series/polynomial rings B : = K 〚 X 〛 [ Y ] ( X , Y ) and C : = K [ Y ] ( Y ) 〚 X 〛 . For each prime ideal P of B ˆ = C ˆ that is maximal with respect to either P ∩ B = ( 0 ) or P ∩ C = ( 0 ) , we prove that P has height n + m − 2 . We also prove each prime ideal P of K 〚 X , Y 〛 that is maximal with respect to P ∩ K 〚 X 〛 = ( 0 ) is of height either m or n + m − 2 .
A heterocyclic molecule with significant activity against dengue virus.

The etiological agents of dengue fever (DF) and dengue hemorrhagic fever (DHF) are four closely related dengue viruses, which are antigenically similar but immunologically distinct serotypes of the family called Flavivirus.1–3 The major vector for these viruses is the mosquito, Aedes aegypti. Estimates make the number of cases of dengue fever as high as 100 million annually, which makes this arthropod-borne viral infection a serious global health problem.4 Dengue virus genome is a single, positive-stranded RNA of about 11 kD with a 5′-cap but without a polyadenylated terminus. After fusion and entry, translation of genomic RNA occurs in infected cells.1,3 Processing of the viral polyprotein is apparently catalyzed by both viral and cellular enzymes. NS proteins are involved in the replication cycle. For example, the NS3 viral protease protein is essential for viral replication.5 The NS5 conserved protein has a methyltransferase motif in the N-terminal domain and an RNA-dependent RNA polymerase in the C-terminal domain. The transferase and polymerase are possible viral targets in antiviral strategies.5–7 However, there are no specific approved drugs or vaccines for the treatment or prevention of DF and DHF. This communication reports on the synthesis and antiviral activity of a novel, uracil-based multifunctional compound, 1, which is a potent inhibitor of the replication of dengue virus. In contrast, its deaza analog, 2, was inactive against this flavivirus (Figure 1). Figure 1 Structures of target compounds
Weak-star convergence in multiparameter Hardy spaces

We prove a multiparameter version of a classical theorem of Jones and Journe on weak-star convergence in the Hardy space H 1 .
Sum-networks from undirected graphs: Construction and capacity analysis

We consider a directed acyclic network with multiple sources and multiple terminals where each terminal is interested in decoding the sum of independent sources generated at the source nodes. We describe a procedure whereby a simple undirected graph can be used to construct such a sum-network and demonstrate an upper bound on its computation rate. Furthermore, we show sufficient conditions for the construction of a linear network code that achieves this upper bound. Our procedure allows us to construct sum-networks that have any arbitrary computation rate p/q (where p, q are non-negative integers). Our work significantly generalizes a previous approach for constructing sum-networks with arbitrary capacities. Specifically, we answer an open question in prior work by demonstrating sum-networks with significantly fewer number of sources and terminals.
Affirmative action retrenchment in public procurement and contracting

This article provides estimates of the impacts of a race-neutral programme called an Emerging Small Business Enterprise (ESBE) Programme in New Jersey in 2003–2004 on women- and minority-owned contractors. We show that although women- and minority-owned firms conceptually benefit from ESBE set-asides, they do not benefit as much as non-Disadvantaged Business Enterprises (DBEs), resulting in a reduced share of total contract dollars awarded to DBEs.
Defining an agenda for human-centered computing

Two workshops sponsored by the National Science Foundation (NSF) were held in September 2006 at NSF headquarters in Arlington, Virginia, with the goal of identifying important and emerging research areas and trends in Human-Centered Computing (HCC). In this article we report on these workshops, each of which was attended by about 30 prominent researchers in the area.
Weakly Nonlinear Investigation of the Saffman–Taylor Problem in a Rectangular Hele–Shaw Cell

We analyze the Saffman–Taylor viscous fingering problem in rectangular geometry. We investigate the onset of nonlinear effects and the basic symmetries of the mode coupling equations, highlighting the link between interface asymmetry and viscosity contrast. Symmetry breaking occurs through enhanced growth of sub-harmonic perturbations. Our results explain the absence of finger tip-splitting in the early flow stages, and saturation of growth rates compared with the predictions of linear stability.
The computation of cloud base height from paired whole-sky imaging cameras

We have developed a novel approach to the extraction of cloud base height (CBH) from pairs of whole-sky imagers (WSIs). The core problem is to spatially register cloud fields from widely separated WSIs; this complete, triangulation provides the CBH measurements. The wide camera separation and the self-similarity of clouds defeats standard matching algorithms when applied to static views of the sky. In response, we use optical flow methods that exploit the fact that modern WSIs provide image sequences. We will describe the algorithm, a confidence metric for its performance, a method to correct the severe projective effects of the WSI camera, and results on real data.
Exact numerical computation in algebra and geometry

Many problems in Computational Science & Engineering (CSE) are defined on the continuum. Standard algorithms for these problems are numerical and approximate. Their computational techniques include iteration, subdivision, and approximation. Such techniques are rarely seen in exact or algebraic algorithms. In this tutorial, we discuss a mode of computation called exact numerical computation (ENC) that achieves exactness through numerical approximation. Through ENC, we can naturally incorporate iteration, subdivision and approximation into the design of exact algorithms for computer algebra and computational geometry. Such algorithms are both novel and practical. This tutorial on ENC is divided into three equal parts:(a) Zero Problems(b) Explicitation Problems(c) Techniques and Complexity Analysis of Adaptivity
Heterogeneous impacts of staggered boards by ownership concentration

Abstract Previous studies provide evidence of a negative relationship between staggered boards and firm value. However, these studies use specifications that do not allow for the heterogeneous impacts of staggered boards for different subsets of firms as predicted by theory. This paper presents more detailed hypotheses regarding how the impact of staggered boards should vary with the probability of takeover. Empirical findings using outside ownership concentration as a proxy for that probability confirm predictions that while for most firms staggered boards do have a negative impact on firm value, for a substantial and identifiable subset of firms staggered boards appear benign.
On questions of decay and existence for the viscous Camassa–Holm equations

Abstract We consider the viscous n-dimensional Camassa–Holm equations, with n = 2 , 3 , 4 in the whole space. We establish existence and regularity of the solutions and study the large time behavior of the solutions in several Sobolev spaces. We first show that if the data is only in L 2 then the solution decays without a rate and that this is the best that can be expected for data in L 2 . For solutions with data in H m ∩ L 1 we obtain decay at an algebraic rate which is optimal in the sense that it coincides with the rate of the underlying linear part.
Differential Mass and Energy Balances in the Flame Zone From a Practical Fuel Injector in a Technology Combustor

This paper presents further analysis of experimental results from an Air Force program conducted by researchers at Brigham Young University (BYU), Wright-Patterson Air Force Base (SPAFB), and Pratt and Whitney Aircraft Co. (P and W) (Hedman et al., 1994a, 1995). These earlier investigations of the combustion of propane in a practical burner installed in a technology combustor used: (1) digitized images from video and still film photographs to document observed flame behavior as fuel equivalence ratio was varied, (2) sets of LDA data to quantify the velocity flow fields existing in the burner, (3) CARS measurements of gas temperature to determine the temperature field in the combustion zone, and to evaluate the magnitude of peak temperature, and (4) two-dimensional PLIF images of OH radical concentrations to document the instantaneous location of the flame reaction zones. This study has used the in situ velocity and temperature measurements from the earlier study, suitably interpolated, to determine local mass and energy balances on differential volume elements throughout the flame zone. The differential mass balance was generally within about {+-}10 percent with some notable exceptions near regions of very high shear and mixing. The local differential energy balance has qualitatively identified the regions ofmore » the flame where the major heat release is occurring, and has provided quantitative values on the rate of energy release (up to {minus}400 kJ/m{sup 3} s). The velocity field data have also been used to determine Lagrangian pathlines through the flame zone. The local velocity and temperature along selected pathlines have allowed temperature timelines to be determined. The temperature generally achieves its peak value, often near the adiabatic flame temperature, within about 10 ms. These temperature timelines, along with the quantitative heat release data, may provide a basis for evaluating kinetic combustion models.« less
Direct comparison between experiments and computations at the atomic length scale: a case study of graphene

This paper discusses a set of recent experimental results in which the mechanical properties of monolayer graphene molecules were determined. The results included the second-order elastic modulus which determines the linear elastic behavior and an estimate of the third-order elastic modulus which determines the non-linear elastic behavior. In addition, the distribution of the breaking force strongly suggested the graphene to be free of defects, so the measured breaking strength of the films represented the intrinsic breaking strength of the underlying carbon covalent bonds. The results of recent simulation efforts to predict the mechanical properties of graphene are discussed in light of the experiments. Finally, this paper contains a discussion of some of the extra challenges associated with experimental validation of multi-scale models.