cssi/SciSciGPT-SciSciNet huggingface dataset:
WIND-DRIVEN CURRENTS IN A SHALLOW LAKE OR SEA

A technique is given for obtaining exact analytical solutions for wind-driven currents in a shallow lake or sea with a large class of bottom topographies which may or may not contain an island. Welander's second-order partial differential equation for the lake's surface displacement is used for determining the lake circulation. The technique, together with some results based on conformal mapping, is used to reduce the problem of finding solutions to Welander's equation for a closed body of water to the problem of solving an ordinary differential equation. The method is applied to an elliptically shaped lake and a circular lake containing an eccentrically located circular island.
Lightning threat to aircraft: Do we know all we need to know?

The problem of lightning threat to aircraft has two aspects: strike avoidance and aircraft protection. These two issues are addressed under the following topics: (1) lightning strikes, weather conditions, and natural lightning rate; (2) the engineering vs. scientific approach to aircraft protection; and (3) the additional information needed to understand lightning threat to aircraft.
Asymptotic distributions of quantum walks on the line with two entangled coins

We advance the previous studies of quantum walks on the line with two coins. Such four-state quantum walks driven by a three-direction shift operator may have nonzero limiting probabilities (localization), thereby distinguishing them from the quantum walks on the line in the basic scenario (i.e., driven by a single coin). In this work, asymptotic position distributions of the quantum walks are examined. We derive a weak limit for the quantum walks and explicit formulas for the limiting probability distribution, whose dependencies on the coin parameter and the initial state of quantum walks are presented. In particular, it is shown that the weak limit for the present quantum walks can be of the form in the basic scenario of quantum walks on the line, for certain initial states of the walk and certain values of the coin parameter. In the case where localization occurs, we show that the limiting probability decays exponentially in the absolute value of a walker's position, independent of the parity of time.
Reduction of feedback loops in sequential circuits and carry leads in iterative networks

Techniques are presented for making use of “previous≓ inputs and outputs in designing sequential circuits and iterative networks. Theorems are proved regarding the maximum reduction in feedback loops or carry leads which can be obtained by the use of such techniques. An algorithm for testing whether a given state table corresponds to a definite event results as a by-product of the more general techniques presented here.
On the evolution of global strings in the early universe

Abstract We find that a bent global string straightens itself out by dissipation into Nambu-Goldstone (NG) bosons in the order of one oscillation time and that the spectrum of radiated NG bosons is 1/k. In the early universe, the assumption that there is one global string per causal horizon is justified after an initial period during which the effect of the primordial plasma on the motion of the strings is non-negligible. We find that the upper bound that axion radiation by strings places on the axion decay constant is comparable to, but not more stringent than the one derived from coherent oscillations of the axion field, i.e. ∫a ≲ 1012GeV. We also discuss the model-dependence of this bound.
Collective excitations in superconductors and semiconductors in the presence of a condensed phase

We first study the spectrum of the excitonic polaritons in semiconductors in the presence of a condensed phase. With the help of the Hubbard-Stratonovich transformation we propose an exact mapping of the extended Hubbard model onto an excitonic-polariton model describing the light propagation in semiconductors. This approach allows us to derive exact formulas for spin-spin and charge-charge correlation functions for spin-triplet superconductivity.
Overcharging of a macroion by an oppositely charged polyelectrolyte

Abstract Complexation of a polyelectrolyte with an oppositely charged spherical macroion is studied for both salt-free and salty solutions. When a polyelectrolyte winds around the macroion, its turns repel each other and form an almost equidistant solenoid. It is shown that this repulsive correlations of turns lead to the charge inversion: more polyelectrolyte winds around the macroion than it is necessary to neutralize it. The charge inversion becomes stronger with increasing concentration of salt and can exceed 100%. Monte-Carlo simulation results agree with our analytical theory.
Electronic structure of coinage metal clusters

Abstract Recent theoretical calculations which employed a multiconfiguration self-consistent field (MCSCF) followed by a multireference configuration interaction (MRSDCI) method on small coinage metal clusters are reviewed. The theoretical results are compared with experimental values when available. Critical comparisons of the dimers, trimers and tetramers of the coinage metal atoms are made and periodic trends are obtained. The gold clusters, in every case, exhibit anomalies owing to relativistic mass-velocity contractions
Moduli Spaces of Fivebranes on Elliptic Calabi-Yau Threefolds

We present a general method for calculating the classical moduli spaces of fivebranes wrapped on holomorphic curves in elliptically fibered Calabi-Yau threefolds, in particular, in the context of heterotic M-theory. The cases of fivebranes wrapped purely on a fiber curve, purely on a curve in the base and, generically, on a curve with components both in the fiber and the base are each discussed in detail. The number of irreducible components of the fivebrane and their properties, such as their intersections and phase transitions in moduli space, follow from the analysis. Even though generic curves have a large number of moduli, we show that there are isolated curves that have no moduli associated with the Calabi-Yau threefold. We present several explicit examples, including cases which correspond to potentially realistic three family models with grand unified gauge group SU(5).
Wound Healing Primer

Surgeons often care for patients with conditions of abnormal wound healing, which include conditions of excessive wound healing, such as fibrosis, adhesions, and contractures, as well as conditions of inadequate wound healing, such as chronic nonhealing ulcers, recurrent hernias, and wound dehiscences. Despite many recent advances in the field, which have highlighted the importance of adjunct therapies in maximizing the healing potential, such as optimization of nutrition, growth factor therapy, advanced wound dressing materials, and bioengineered skin substitutes, conditions of abnormal wound healing continue to cause significant cost, morbidity, and mortality. To understand how conditions of abnormal wound healing can be corrected, it is important to first understand the basic principles of wound healing.
Density of states and the metal- non-metal transition in the 2-D electron gas

In heterostructures with thick spacer layers the random potential in the channel created by remote impurity ions is smooth and can be treated classically, so that a percolation interpretation of the metal ‐ non‐metal transition (MNMT) is possible. The critical electron density, n c of the MNMT is found as a function of the spacer width and the ion density. The connection between the critical density n c for the transition without magnetic field and the width of the plateaus of the integer quantum Hall effect (IQHE) in a sufficiently strong magnetic field is established. The width of the plateau as a function of spacer thickness and magnetic field is discussed.
Local reference lines for handwritten phrase recognition

Reference line information has been used for diverse purposes in handwriting research, including word case classification, OCR, and holistic word recognition. In this paper, we argue that the commonly used global reference lines are inadequate for many handwritten phrase recognition applications. Individual words may be written at different orientations or vertically displaced with respect to one another. A function used to approximate the implicit baseline will not be differentiable or even continuous at some points. We have presented the case for local reference lines and illustrate its successful use in a system that verifies street name phrases in a postal application.
A SIMPLE TIME SEQUENTIAL PROCEDURE FOR PREDICTING FREEWAY INCIDENT DURATION

The prediction of incident durations can facilitate incident management and support traveler decisions. This paper develops a procedure for predicting incident durations. First, the causal and non-causal factors which influence incident durations are conceptualized. These include operational characteristics such as response times and whether a heavy wrecker was used, incident characteristics such as injuries and number of vehicles involved and environmental conditions such as weather and visibility. Specific hypotheses are tested by developing truncated regression models of incident duration using data provided by the Illinois Department of Transportation (IDOT) on Chicago area freeways. Then, a time sequential methodology is developed to predict the incident durations as information about the incident is acquired in a Traffic Operations Center or TOC. Initially, after an incident is detected, information at a TOC is often acquired at a high rate, then information acquisition levels off and toward the end...
Use of Ultrasonography in the Patient With Acute Abdominal Trauma

ated the role of ultrasonography in patients with acute blunt abdominal trauma.1–7 The focus of these publications has been detection of free fluid in the abdomen or pelvis. In the majority of these publications, ultrasonography has been shown to be much less sensitive in detecting parenchymal organ injuries as compared to detecting free fluid.1,3–7 In patients with blunt abdominal trauma, renal injuries are an infrequent cause of free fluid.1–3 Little specific attention has been paid to the role of the emergent ultrasonogram in evaluating acute renal trauma. Therefore, we focused our attention on a subset of patients with blunt abdominal trauma and a renal injury in which the sonographic examination was performed. Received September 4, 1998, from the Department of Radiology (J.P.M., C.D.J., E.O.G.) and the Division of Emergency Medicine (J.R.R.), University of California, Davis, Medical Center, Sacramento, California. Revised manuscript accepted for publication November 15, 1998. Address correspondence and reprint requests to John P. McGahan, MD, Department of Radiology, UC Davis Medical Center, Ambulatory Care Center, 4860 Y Street, Suite 3100, Sacramento, CA 95817. ABBREVIATIONS
Third‐Party Logistics: A Meta‐Analytic Review and Investigation of its Impact on Performance

Interest in third-party logistics has been steadily increasing over the last two decades. Recently, increased focus by researchers has produced a solid literature base of academic research. In this article, a meta-analytic approach is employed to provide a quantitative review of the empirical literature and examine relevant constructs. Fifty-four samples across 69 peer-reviewed journal articles, yielding a total of 9,386 observations, were obtained and analyzed. We used transaction cost economics and the resource-based view as lenses to hypothesize a structural model of the relationships between relational governance structure, logistics customer service, and firm performance. Additional relationships were also found and analyzed, helping to clarify the mixed existing findings in the literature. The study concludes by mapping out future directions for 3PL research, based on the study's findings.
Spiders in Lyot Coronagraphs

In principle, suppression of on-axis stellar light by a coronagraph is easier on an unobscured aperture telescope than on one with an obscured aperture. Recent designs such as the apodized pupil Lyot coronagraph, the "band-limited" Lyot coronagraph, and several variants of phase-mask coronagraphs work best on unobscured circular aperture telescopes. These designs were developed to enable the discovery and characterization of nearby Jovian or even terrestrial exoplanets. All of today's major space-based and adaptive optics-equipped ground-based telescopes are obscured-aperture systems with a secondary mirror held in place by secondary support "spider" vanes. The presence of a secondary obscuration can be dealt with by ingenious coronagraph designs, but the spider vanes themselves cause diffracted light, which can hamper the search for Jovian exoplanets around nearby stars. We look at the problem of suppressing spider vane diffraction in Lyot coronagraphs, including apodized pupil and band-limited designs. We show how spider vane diffraction can be reduced drastically and in fact contained in the final coronagraphic image, within one resolution element of the geometric image of the focal plane mask's occulting spot. This makes adaptive optics coronagraphic searches for exojupiters possible with the next generation of adaptive optics systems being developed for 8-10 m class telescopes such as Gemini and the Very Large Telescopes.
Low-cycle fatigue crack growth considerations in pipe fracture analyses☆

This paper presents some results from an ORNL cyclic pipe experiment that demonstrated the magnitude of low-cycle fatigue crack growth from simulated seismic loading. The concern with this result is that current pipe flaw evaluation procedures do not consider the cyclic crack growth during a seismic event, i.e. the peak dynamic load is used in a static analysis. This was the main incentive for the analyses developed in this paper. Additional applications of the methodology developed in this paper would be high stress-low cycle fatigue transients that can occur in service. In this paper, we show that the low-cycle fatigue crack growth data from the ORNL pipe test agreed well with the extrapolation of high-cycle fatigue crack growth data from small specimens. The next step was to evaluate the accuracy of several different methods to predict the low-cycle fatigue crack growth. In this evaluation it was found that for low-cycle fatigue LEFM analysis would significantly underpredict the crack growth and EPFM analyses were needed. Three different EPFM analyses were used. The GE/EPRI method was found to be overly conservative, which is consistent with comparisons with past pipe fracture data. The LBB.NRC and LBB.ENG2 J-estimation schemes provided good predictions of the experimental crack growth data when the crack-closure load was taken into account.
APPLICATION OF INVERSIONS TO LOSSLESS IMAGE COMPRESSION

Linear prediction schemes, such as that of the Joint Photographic Experts Group (JPEG), are simple and normally produces a residual sequence with lower zero-order entropy. Occasionally the entropy of the prediction error becomes greater than that of the original image. Such situations frequently occur when the image data have discrete gray levels located within certain intervals. To alleviate this problem, various authors have suggested different preprocessing methods. However, the techniques reported require two passes. We extend the definition of Lehmer-type inversions (Lehmer 1960 and 1964) from permutations to multiset permutations and present a one-pass algorithm based on inversions of a multiset permutation. We obtain comparable results when we apply JPEG and even better results when we apply some other linear prediction schemes on a preprocessed image, which is treated as multiset permutation.
Bayesian experimental design for the active nitridation of graphite by atomic nitrogen

The problem of optimal data collection to efficiently learn the model parameters of a graphite nitridation experiment is studied in the context of Bayesian analysis using both synthetic and real experimental data. The paper emphasizes that the optimal design can be obtained as a result of an information theoretic sensitivity analysis. Thus, the preferred design is where the statistical dependence between the model parameters and observables is the highest possible. In this paper, the statistical dependence between random variables is quantified by mutual information and estimated using a k nearest neighbor based approximation. It is shown, that by monitoring the inference process via measures such as entropy or Kullback–Leibler divergence, one can determine when to stop the data collection process. The methodology is applied to select the most informative designs on both a simulated data set and on an experimental data set, previously published in the literature. It is also shown that the sequential Bayesian analysis used in the experimental design can also be useful in detecting conflicting information between measurements and model predictions.
Determination of Compost Respiration Rates Using Pressure Sensors

Compost stability is one of the most important criteria used to evaluate compost quality. Several of the most popular methods to quantify stability are based on measurements of aerobic respiration of oxygen to carbon dioxide. This study compared two closed-vessel respiration techniques. In both methods, the evolved CO2 was absorbed by sodium hydroxide (NaOH), leading to a pressure drop in the container. The conventional technique measures absorbed CO2 by titrating the NaOH trap, limiting measurement frequency by the need to manually remove and replace the trap. The pressure sensor method (PSM) uses a datalogger to record pressure differences in the vessel, allowing several observations each hour. Samples of bedded swine manure compost (n=125) were analyzed using both the PSM and the titration method (TM) during 48 h incubation at 30°C. Each compost sample was also analyzed for total solids, volatile solids (VS), pH and electrical conductivity. Respiration results obtained using the PSM were compared with ...
Wavelet-Galerkin Discretization of Hyperbolic Equations

The relative merits of the wavelet-Galerkin solution of hyperbolic partial differential equations, typical of geophysical problems, are quantitatively and qualitatively compared to traditional finite difference and Fourier-pseudo-spectral methods. The wavelet-Galerkin solution presented here is found to be a viable alternative to the two conventional techniques.
Alkynoate Synthesis through the Vinylogous Reactivity of Rhodium(II) Carbenoids

Siloxy group migration: A rhodium(II) carbenoid approach has been developed for the synthesis of alkynoates. This transformation combines the addition of enol ethers at the vinylogous position of β-siloxy-substituted vinyldiazo derivatives with a siloxy group migration to give the products as single diastereomers.
The Dragon Is Flying West: Micro-level Evidence of Chinese Outward Direct Investment

Outward direct investment (ODI) from the People's Republic of China (PRC) is surging. A common perception is that it was driven by the country's resource-seeking and technology-seeking motives. Usi...
Laser Prostatectomy Performed with a Right Angle Firing Neodymium: Yag Laser Fiber at 40 Watts Power Setting

AbstractA total of 25 patients with symptomatic bladder outlet obstruction due to benign prostatic hyperplasia was entered into a prospective, randomized trial comparing laser prostatectomy performed with the Urolase**C. R. Bard, Inc., Covington, Georgia. right angle firing neodymium: YAG laser fiber to standard transurethral electroresection of the prostate. Overall acute perioperative morbidity, including blood loss and fluid absorption, was significantly less for patients undergoing laser prostatectomy. Efficacy of treatment was assessed by standardized American Urological Association symptom scores, patient assessment of symptom improvement, peak urinary flow rates and post-void residual urine volumes, and was equivalent for the 2 treatment groups at 3 and 6 months.
Telomerase Activity: A Biomarker of Cell Proliferation, Not Malignant Transformation

Telomerase activity is readily detected in most cancer biopsies, but not in premalignant lesions or in normal tissue samples with a few exceptions that include germ cells and hemopoietic stem cells. Telomerase activity may, therefore, be a useful biomarker for diagnosis of malignancies and a target for inactivation in chemotherapy or gene therapy. These observations have led to the hypothesis that activation of telomerase may be an important step in tumorigenesis. To test this hypothesis, we studied telomerase activity in isogeneic samples of uncultured and cultured specimens of normal human uroepithelial cells (HUCs) and in uncultured and cultured biopsies of superficial and myoinvasive transitional cell carcinoma (TCC) of the bladder. Our results demonstrated that four of four TCC biopsies, representing both superficial and myoinvasive TCCs, were positive for telomerase activity, but all samples of uncultured HUC were telomerase negative. However, when the same normal HUC samples were established as proliferating cultures in vitro, telomerase activity was readily detected but usually at lower levels than in TCCs. Consistent with the above observation of the telomerase activity in HUCs, telomeres did not shorten during the HUC in vitro lifespan. Demonstration of telomerase in proliferating human epithelial cells in vitro was not restricted to HUCs, because it was also present in prostate and mammary cell cultures. Notably, telomerase activity was relatively low or undetectable in nonproliferating HUC cultures. These data do not support a model in which telomerase is inactive in normal cells and activated during tumorigenic transformation. Rather, these data support a model in which the detection of telomerase in TCC biopsies, but not uncultured HUC samples, reflects differences in proliferation between tumor and normal cells in vivo.
CMC Hypersurfaces on Riemannian and Semi-Riemannian Manifolds

In this paper we generalize the explicit formulas for constant mean curvature (CMC) immersion of hypersurfaces of Euclidean spaces, spheres and hyperbolic spaces given in Perdomo (Asian J Math 14(1):73–108, 2010; Rev Colomb Mat 45(1):81–96, 2011) to provide explicit examples of several families of immersions with constant mean curvature and non constant principal curvatures, in semi-Riemannian manifolds with constant sectional curvature. In particular, we prove that every \(h\in[-1,-\frac{2\sqrt{n-1}}{n})\) can be realized as the constant curvature of a complete immersion of \(S_1^{n-1}\times \mathbb{R}\) in the (n + 1)-dimensional de Sitter space \(\hbox{\bf S}_1^{n+1}\). We provide 3 types of immersions with CMC in the Minkowski space, 5 types of immersion with CMC in the de Sitter space and 5 types of immersion with CMC in the anti de Sitter space. At the end of the paper we analyze the families of examples that can be extended to closed hypersurfaces.
Dark matter dynamics and indirect detection

Non-baryonic, or "dark", matter is believed to be a major component of the total mass budget of the Universe. We review the candidates for particle dark matter and discuss the prospects for direct detection (via interaction of dark matter particles with laboratory detectors) and indirect detection (via observations of the products of dark matter self-annihilations), focusing in particular on the Galactic center, which is among the most promising targets for indirect detection studies. The gravitational potential at the Galactic center is dominated by stars and by the supermassive black hole, and the dark matter distribution is expected to evolve on sub-parsec scales due to interaction with these components. We discuss the dominant interaction mechanisms and show how they can be used to rule out certain extreme models for the dark matter distribution, thus increasing the information that can be gleaned from indirect detection searches.
Image coding based on two-channel conjugate VQ

Abstract Two-channel conjugate VQ (TCCVQ) has been recently proposed for speech coding. Compared to ordinary VQ, two-channel conjugate VQ requires less computational complexcity and less storage (memory) and is more robust against channel errors. This technique is now extended to image coding. The emphasis in this paper is on the usefulness of the TCCVQ when it is applied to image coding or is combined with a conventional image coding technique. Initial investigation confirms these advantages of two-channel conjugate VQ. For a noise-free channel the performances of both techniques are similar. However, when channel noise is injected, for the same bit rate, images reconstructed based on two-channel conjugate VQ are subjectively more pleasing (have less visible distortion) than those based on ordinary VQ. Both VQ techniques are also applied to a well-known separating mean VQ and are tested for robustness against channel errors. Computer simulations demonstrate the success of the two-channel conjugate VQ technique for image data compression at various bit rates.
Glass formation and crystallization in high-temperature glass-ceramics and Si3N4

Abstract The softening of glassy grain boundaries in ceramic matrix composites and silicon nitride at high temperatures reduces mechanical strength and the upper-use temperature. By crystallizing this glass to more refractory crystalline phases, a material which performs at higher temperatures may result. Three systems were examined: a cordierite composition with zirconia as a nucleating agent; celsian compositions; and yttrium silicate glasses both in bulk and intergranular in silicon nitride. For the cordierite compositions, a series of metastable phases was obtained. The crystallization of these compositions was summarized in terms of metastable ternary isothermal sections. Zircon formed at the expense of zirconia and spinel. In SiC composites the transformations were slower. In celsian, two polymorphs were crystallized. One phase, hexacelsian, which always crystallized, even when metastable, had an undesirable volume change. The other phase, celsian, was very difficult to crystalline. In yttrium silicate bulk glasses, similar in composition to the intergranula rglass in silicon nitride, a number of polymorphs of Y2Si2O7 were crystallized. The conditions under which these polymorphs formed are compared with crystallization in silicon nitride.
Progress and Future Prospects for Particle-Based Simulation of Hypersonic Flow

Abstract The direct simulation Monte Carlo method (DSMC) has evolved over 50 years into a powerful numerical technique for the computation of thermochemical nonequilibrium gas flows. In this context, nonequilibrium means that velocity and internal energy distribution functions are not in equilibrium forms due to a low number of intermolecular collisions within a fluid element. In hypersonic flow, nonequilibrium conditions occur at high altitude and in regions of flow fields with small length scales. This article highlights significant developments in particle simulation methods (since 2001) applied specifically to hypersonic flows, which now includes Molecular Dynamics in addition to DSMC. Experimental measurements that have led directly to improved DSMC models will be highlighted. Algorithm development for DSMC aimed at increasing computational efficiency is discussed with a focus on hybrid particle-continuum methods. New research that applies all-atom Molecular Dynamics simulation and trajectory-based DSMC simulation to normal shock waves is summarized. Finally, a discussion of state-resolved DSMC modeling is included with reference to future prospects for particle simulation methods and in particular for the DSMC method.
Oncogenes and tumor suppressor genes

In the past 15 years, many of the mechanisms underlying the molecular origins of cancer have been uncovered, and a clear picture of the role of oncogenes and tumor suppressor genes in carcinogenesis has developed. This article reviews the mechanisms by which oncogenes and tumor suppressor genes participate in the creation of tumors.
Torso loading via a harness method activates trunk muscles less than a hand loading method

There is a need for data comparing muscle activity under equivalent moments at the torso using different loading methods. In torso biomechanics, it is often necessary to apply moments to people and then measure or predict the muscle activity in response to the external load. Alternative methods exist to generate moments including applying forces by a chest harness and loads held in the hands. The limitation of previous research has been to use only one of the loading methods, generally harness loading, assuming it produces muscle activity equal to when loads are held in the hands. The objective of the this study was to test if equivalent moments at L3/L4 applied to subjects through two loading methods resulted in the same muscle activity. Subjects maintained a static posture while attempting a combination of flexion/extension, lateral bending, and torsion to counter the external loads applied via hand and harness loading methods. Hand and harness loading did not result in equal muscle activity as measured by electromyographic techniques. The left and right latissimus dorsi had increases in activity (16-25%) when loads were held with the hands instead of applied via the harness. Increased activity for hand loading was also found for the left and right rectus abdominis (13-17%) and left external oblique (24%). The left and right erector spinae and right external oblique exhibited the same activity for both loading methods. The current findings indicate that studies of torso loading using a shoulder harness to create torso moments may be lowering activity of some torso muscles.
Generalized isoperimetric inequalities.

Continuing the development of a previous paper on generalized isoperimetric inequalities (i.e., rearrangement inequalities for Green's functions), we extend the theory to the case of Green's functions for a potential which approaches zero at infinity. Specialization to domain potentials and long times gives Polya and Szego's isoperimetric inequality for the electrostatic capacity. Long times and a more general potential give a new isoperimetric inequality (for the ``scattering length'' of a potential). We also obtain from another specialization a curious isoperimetric inequality for the trace of the phase shift operator of scattering theory (for a given energy).
Interest rate volatility and home mortgage loans

The US economy has experienced substantial fluctuations in real and nominal interest rates since the 1970s. This article investigates empirically the relationship between home mortgage loans and volatility in mortgage rates for the period 1971:02 to 2003:03. Contrary to common wisdom, we find a positive relationship between mortgage rate volatility and home mortgage loans. Further investigation indicates that this is due to volatility in the bond market. In times of high interest volatility, households disinvest in government securities and invest in real assets, which yields a positive relationship between mortgage rate volatility and home mortgage loans.
Calculations with DLCQ

Abstract The method of discrete light-cone quantization (DLCQ) and useful refinements are summarized. Applications to various field theories are reviewed.
Atomic structure of the Y complex of the nuclear pore

The nuclear pore complex (NPC) is the principal gateway for transport into and out of the nucleus. Selectivity is achieved through the hydrogel-like core of the NPC. The structural integrity of the NPC depends on ~15 architectural proteins, which are organized in distinct subcomplexes to form the >40-MDa ring-like structure. Here we present the 4.1-A crystal structure of a heterotetrameric core element ('hub') of the Y complex, the essential NPC building block, from Myceliophthora thermophila. Using the hub structure together with known Y-complex fragments, we built the entire ~0.5-MDa Y complex. Our data reveal that the conserved core of the Y complex has six rather than seven members. Evolutionarily distant Y-complex assemblies share a conserved core that is very similar in shape and dimension, thus suggesting that there are closely related architectural codes for constructing the NPC in all eukaryotes.
CP-violating lepton asymmetries from B decays and their implication for supersymmetric flavor models

Abstract The lepton and dilepton charge asymmetries from B d and B s are predicted to be small in the standard model, whereas new physics could increase their values significantly. In this paper, we explore the use of the lepton asymmetries as a probe of the flavor structure of supersymmetric theories. In particular, we determine the sensitivity to parameters of various models. We find that in many interesting models which attempt to address the supersymmetric flavor problem, the mixing structure is such that it could be possible to detect new physics. The predictions are model dependent; with a measurement in both the B s and B d systems one can hope to constrain the flavor physics model, especially once squarks are detected and their masses measured. Thus, lepton charge asymmetries can be used as an alternative means of searching for new physics and distinguishing among potential solutions to the flavor problem. They are interesting precisely because they are small in the standard model and are therefore necessarily evidence of new physics.
A finite mixture model of vehicle-to-vehicle and day-to-day variability of traffic network travel times

This study proposes an approach to modeling the effects of daily roadway conditions on travel time variability using a finite mixture model based on the Gamma–Gamma (GG) distribution. The GG distribution is a compound distribution derived from the product of two Gamma random variates, which represent vehicle-to-vehicle and day-to-day variability, respectively. It provides a systematic way of investigating different variability dimensions reflected in travel time data. To identify the underlying distribution of each type of variability, this study first decomposes a mixture of Gamma–Gamma models into two separate Gamma mixture modeling problems and estimates the respective parameters using the Expectation–Maximization (EM) algorithm. The proposed methodology is demonstrated using simulated vehicle trajectories produced under daily scenarios constructed from historical weather and accident data. The parameter estimation results suggest that day-to-day variability exhibits clear heterogeneity under different weather conditions: clear versus rainy or snowy days, whereas the same weather conditions have little impact on vehicle-to-vehicle variability. Next, a two-component Gamma–Gamma mixture model is specified. The results of the distribution fitting show that the mixture model provides better fits to travel delay observations than the standard (one-component) Gamma–Gamma model. The proposed method, the application of the compound Gamma distribution combined with a mixture modeling approach, provides a powerful and flexible tool to capture not only different types of variability—vehicle-to-vehicle and day-to-day variability—but also the unobserved heterogeneity within these variability types, thereby allowing the modeling of the underlying distributions of individual travel delays across different days with varying roadway disruption levels in a more effective and systematic way.
Catalysis Science of Bulk Mixed Oxides

Bulk mixed oxide catalysts are widely used for various applications (selective oxidation catalysts, electrocatalysts for solid oxide fuel cells, and solid oxide electrolyzers for the production of hydrogen), but fundamental understanding of their structure–performance relationships have lagged in the literature. The absence of suitable surface composition and surface structural characterization techniques and methods to determine the number of catalytic active sites, with the latter needed for determination of specific reaction rates (e.g., turnover frequency (1/s)), have hampered the development of sound fundamental concepts in this area of heterogeneous catalysis. This Perspective reviews the traditional concepts that have been employed to explain catalysis by bulk mixed oxides (molybdates, vanadates, spinels, perovskites, and several other specific mixed oxide systems) and introduces a modern perspective to the fundamental surface structure–activity/selectivity relationships for bulk mixed oxide cataly...
Collective-Field Acceleration of High-Energy Ions

A collective-field accelerator has evolved from experimental and theoretical research at the Lawrence Livermore Laboratory that uses a high-vacuum diode with an adjustable graphite cathode as well, as an insulated anode, and that operates with a relativistic electron beam with ν/γ of ~1. Alternate gradient lenses are used to focus collectively accelerated particles. The gradients are produced by alternate dielectric and grounded lenses. The dielectric lenses are self charged by the electron beam creating a potential difference in reference to the grounded lenses. These lenses focus both electrons and ions by convective processes. Deuterons have been accelerated in pulses of ~1014 producing up to 1011 D-D neutrons per burst by impingement on suitable targets. Hydrogen, deuterium, carbon, fluorine and chlorine ions have been accelerated to produce both light-and heavy-ion reactions. Analysis of activation data shows that heavy ions with >6 MeV per nucleon and protons with ~15 MeV energy have been produced. Theoretical analysis indicates that the collective ion acceleration mechanisms arise from interactions with plasma-wave trains created by near-resonant, beam-cavity interactions and accelerated (in group velocity) through density and temperature gradients in the secondary plasma beyond the anode.
Renormalization-group study of a magnetic impurity in a Luttinger liquid

A generalized Anderson model for a magnetic impurity in an interacting one-dimensional electron gas is studied via a mapping onto a classical Coulomb gas. For weak potential scattering, the local-moment parameter regime expands as repulsive bulk interactions become stronger, but the Kondo scale for the quenching of the impurity moment varies non-monotonically. There also exist two regimes dominated by backward potential scattering: one in which the impurity is non-magnetic, and another in which an unquenched local moment survives down to very low temperatures.
Homological properties of quantized coordinate rings of semisimple groups

We prove that the generic quantized coordinate ring $\mathcal{O}_q(G)$ is Auslander-regular, Cohen-Macaulay, and catenary for every connected semisimple Lie group $G$. This answers questions raised by Brown, Lenagan, and the first author. We also prove that under certain hypotheses concerning the existence of normal elements, a noetherian Hopf algebra is Auslander-Gorenstein and Cohen-Macaulay. This provides a new set of positive cases for a question of Brown and the first author.
Nucleation theory of overdamped soliton motion

We consider a ring of tightly torsion-coupled, overdamped pendulums subject to an external torque and coupled to a thermal reservoir. At low temperatures the dynamics of this system, over a wide range of forces, is governed by thermally activated kink-antikink pairs, their subsequent separation through the external force, and eventual recombination by collision with other kinks. We calculate the thermal activation rate of kink-antikink pairs using an approach first developed by Brinkman. This theory requires a detailed investigation of the multidimensional saddle, which has to be crossed, if the system is to make a thermally activated transition. The propagation velocity of the driven kinks is calculated. We use these results to derive the mean angular pendulum velocity as a function of the applied torque. Comparison is made with earlier work.
Notes on the (2+1)-dimensional Wheeler-DeWitt equation

In contrast to other approaches to (2+1)-dimensional quantum gravity, the Wheeler--DeWitt equation appears to be too complicated to solve explicitly, even for simple spacetime topologies. Nevertheless, it is possible to obtain a good deal of information about solutions and their interpretation. In particular, strong evidence is presented that Wheeler--DeWitt quantization is not equivalent to reduced phase space quantization.
Development of the astronomical image archive and catalog database for production of GSC—II

Abstract The Catalogs and Surveys Branch (CASB) of the Space Telescope Science Institute (STScI), in collaboration with a number of international astronomical institutions, is continuing with the development and creation of an archive of digitized images, and an associated catalog of stars and galaxies which cover the entire sky. These data are being made available to the astronomical community to support telescope operations and research projects.
Optimization of Regenerated Gas Turbines

An algorithm for the optimization of regenerated gas turbines is given. For sets of inputs that are typical for automotive applications, the optimum cycle pressure ratio and a set of optimized regenerator parameters that maximize thermal efficiency are given. A second algorithm, an algorithm for sizing regenerators based on outputs of the optimization algorithm, is given. With this sizing algorithm, unique regenerator designs can be determined for many applications based on the presented optimization data. Results of example sizings are given. The data indicate that one core (instead of two cores) should be used to maximize thermal efficiency. The data also indicate that thermal efficiencies of over 50 percent should be achievable for automotive applications if ceramic turbines are used.
Kalman filter control of a model of spatiotemporal cortical dynamics

Recent advances in Kalman filtering to estimate system state and parameters in nonlinear systems have offered the potential to apply such approaches to spatiotemporal nonlinear systems. We here adapt the nonlinear method of unscented Kalman filtering to observe the state and estimate parameters in a computational spatiotemporal excitable system that serves as a model for cerebral cortex. We demonstrate the ability to track spiral wave dynamics, and to use an observer system to calculate control signals delivered through applied electrical fields. We demonstrate how this strategy can control the frequency of such a system, or quench the wave patterns, while minimizing the energy required for such results. These findings are readily testable in experimental applications, and have the potential to be applied to the treatment of human disease.
The extracellular matrix Component Psl provides fast-acting antibiotic defense in Pseudomonas aeruginosa biofilms.

Bacteria within biofilms secrete and surround themselves with an extracellular matrix, which serves as a first line of defense against antibiotic attack. Polysaccharides constitute major elements of the biofilm matrix and are implied in surface adhesion and biofilm organization, but their contributions to the resistance properties of biofilms remain largely elusive. Using a combination of static and continuous-flow biofilm experiments we show that Psl, one major polysaccharide in the Pseudomonas aeruginosa biofilm matrix, provides a generic first line of defense toward antibiotics with diverse biochemical properties during the initial stages of biofilm development. Furthermore, we show with mixed-strain experiments that antibiotic-sensitive “non-producing” cells lacking Psl can gain tolerance by integrating into Psl-containing biofilms. However, non-producers dilute the protective capacity of the matrix and hence, excessive incorporation can result in the collapse of resistance of the entire community. Our data also reveal that Psl mediated protection is extendible to E. coli and S. aureus in co-culture biofilms. Together, our study shows that Psl represents a critical first bottleneck to the antibiotic attack of a biofilm community early in biofilm development.
The weak mixing angle from an SU(3) symmetry at a TeV

Abstract The measured values of two electroweak gauge couplings appear to obey an approximate (5%) SU (3) relation. Unless this is an coincidence caused by fortuitous Planck-scale physics, it suggests the presence of an SU (3) symmetry near the electroweak scale. We propose this to be a local SU (3) which spontaneously “mixes” with SU (2)× U (1) near a TeV. Although all the particles of the standard model are SU (3)-singlets, this symmetry relates the electroweak gauge couplings and can successfully predict the weak mixing angle with a precision of a few percent. Since this mechanism operates at a TeV, it does not require an energy desert and consequently can be embedded in theories of TeV-gravity.
Induced modules for vertex operator algebras

For a vertex operator algebraV and a vertex operator subalgebraV′ which is invariant under an automorphismg ofV of finite order, we introduce ag-twisted induction functor from the category ofg-twistedV′-modules to the category ofg-twistedV-modules. This functor satisfies the Frobenius reciprocity and transitivity. The results are illustrated withV′ being theg-invariants in simpleV orV′ beingg-rational.
Global Sensitivity Results for Generalized Least Squares Estimates

Abstract The covariance matrix for the residuals of a regression process is written as the identity matrix plus a matrix V. The matrix V is bounded from above, and the corresponding set of generalized least squares estimates is identified. The extreme estimates in this set are functions of the usual t statistics; in particular the number ((T - k)/8)1/2/|t| measures the influence of reweighting extreme observations, where T - k gives the degrees of freedom, t is the t statistic, and the weights on observations are allowed to vary by a factor of at most 2.
The importance of Ada programming support environments

In this paper it is argued that even if we assume the most optimistic scenario we can think up for the introduction of the Ada language, the language alone, in the absence of an Ada Programming Support Environment (APSE), is insufficient to achieve the gains in programming productivity and software reliability with which use of Ada tantalizes us.Moreover, it is argued that the level of support envisaged in the Minimal Ada Programming Support Environment (MAPSE), specified in the STONEMAN, which provides a rudimentary level of capability incorporating a text editor, compiler, linker/loader, and symbolic debugger, is also insufficient; and that it is time to seize the opportunity to conceptualize what sort of advanced programming support tools should populate a mature APSE of high utility and effectiveness. In this context, consideration of support tools for software project management, interactive programming, modern programming practices, software reuse, and improved program understanding techniques arises.
On Mutual Fund Investment Styles

Most mutual funds adopt investment styles that cluster around a broad market benchmark. Few funds take extreme positions away from the index, but those who do are more likely to favor growth stocks and past winners. The bias toward glamour and the tendency of poorly performing value funds to shift styles may reflect agency and behavioral considerations. After adjusting for style, there is evidence that growth managers on average outperform value managers. Though a fund's factor loadings and its portfolio characteristics generally yield similar conclusions about its style, an approach using portfolio characteristics predicts fund returns better. Copyright 2002, Oxford University Press.