cssi/SciSciGPT-SciSciNet huggingface dataset:
Multiple Permanent‐wave Trains in Nonlinear Systems

Multiple permanent-wave trains in nonlinear systems are constructed by the asymptotic tail-matching method. Under some general assumptions, simple criteria for the construction are presented. Applications to fourth-order systems and coupled nonlinear Schrodinger equations are discussed.
Sulfinimine mediated asymmetric synthesis of 3-substituted-1(2H)-isoquinolones: (3R,4S)-(−)-4-hydroxy-3-phenyltetrahydroisoquinoline

Abstract A general approach to enantiomerically pure 3-substituted-1(2H)-isoquinolones is illustrated by the addition of lateral lithiated amide 7 to sulfinimine 5. Isoquinolone 8 is readily transformed into (3R,4S)-(−)-4-hydroxy-3-phenyltetrahydroisoquinoline 15 via hydroxylation and reduction.
The effect of international diversification on corporate financing policy

Abstract The purpose of this study is to investigate whether international operations have a discernible effect on the financing policies of U.S.- based firms. Results obtained indicate that firms with notable foreign involvement have target leverage ratios significantly below those of their domestic counterparts. It is also found that multinationals secure a greater portion of their borrowing from short-term sources. These results are rationalized in terms of the market imperfections that the multinationals face and/or exploit.
A CONVERGENT ROUTE FOR THE TOTAL SYNTHESIS OF THE ELEUTHESIDES

A ring expansion/ring contraction sequence is one of the key steps in the stereoselective synthesis of the tricyclic eleutheside skeleton 2 from α-phellandrene 1. Eleuthesides are natural products that are isolated from different marine sources, and several of these compounds display taxol-like anticancer activity.
Performance limiting effects in X-band accelerators

Acceleration gradient is a critical parameter for the design of future TeV-scale linear colliders. The major obstacle to higher gradient in room-temperature accelerators is rf breakdown, which is still a very mysterious phenomenon that depends on the geometry and material of the accelerator as well as the input power and operating frequency. Pulsed heating has been associated with breakdown for many years; however, there have been no experiments that clearly separate field and heating effects on the breakdown rate. Recently, such experiments have been performed at SLAC with both standing-wave and traveling-wave structures. These experiments have demonstrated that pulsed heating is limiting the gradient. Nevertheless the $X$-band structures breakdown studies show damage to the iris surfaces in locations of high electric field rather than of high magnetic field after thousands of breakdowns. It is not yet clear how the relative roles of electric field, magnetic field, and heating factor into the damage caused by rf breakdown. Thus, a dual-moded cavity has been designed to better study the electric field, magnetic field, and pulsed heating effects on breakdown damage.
A Historical and Current Perspective on Predicting Thermal Cookoff Behavior

Prediction of thermal explosions using chemical kinetic models dates back nearly a century. However, it has only been within the past 25 years that kinetic models and digital computers made reliable predictions possible. Two basic approaches have been used to derive chemical kinetic models for high explosives: [1] measurement of the reaction rate of small samples by mass loss (thermogravimetric analysis, TG), heat release (differential scanning calorimetry, DSC), or evolved gas analysis (mass spectrometry, infrared spectrometry, etc.) or [2] inference from larger-scale experiments measuring the critical temperature (T m, lowest T for self-initiation), the time to explosion as a function of temperature, and sometimes a few other results, such as temperature profiles. Some of the basic principles of chemical kinetics involved are outlined, and major advances in these two approaches through the years are reviewed.
Simulation of collisional effects in plasmas

Abstract A computer simulation method has been developed to simulate collisional effects in plasmas in the regime where plasma instabilities are dominant but are modified by weak collisions. The algorithm is based on the method of periodic smoothing in phase space, in which collisions are introduced at reconstruction times in terms of a one-dimensional Fokker-Planck operator with a velocity dependent collision frequency. The results of test problems, including approach to equilibrium, collisional heating, and plasma echo decay, are presented.
Time and Matter in the Interaction Between Gravity and Quantum Fluids:. are There Macroscopic Quantum Transducers Between Gravitational and Electromagnetic Waves?

Measurements of the tunneling time are briefly reviewed. Next, time and matter in general relativity and quantum mechanics is examined. In particular, the question arises: How does gravitational radiation interact with a coherent quantum many-body system (a “quantum fluid”)? A minimal coupling rule for the coupling of the electron spin to curved spacetime in general relativity implies the possibility of a coupling between electromagnetic (EM) and gravitational (GR) radiation mediated by a quantum Hall fluid. This suggests that quantum transducers between these two kinds of radiation fields might exist. We report here on a first attempt at a Hertz-type experiment, in which a high-Tc superconductor (YBCO) was the material used as a quantum transducer to convert EM into GR microwaves, and a second piece of YBCO in a separate apparatus was used to back-convert GR into EM microwaves. An upper limit on the conversion efficiency of YBCO was measured to be 1.6 × 10 −5 .
Adaptive Uncertainty Resolution in Bayesian Combinatorial Optimization Problems

In several applications such as databases, planning, and sensor networks, parameters such as selectivity, load, or sensed values are known only with some associated uncertainty. The performance of such a system (as captured by some objective function over the parameters) is significantly improved if some of these parameters can be probed or observed. In a resource constrained situation, deciding which parameters to observe in order to optimize system performance, itself becomes an interesting and important optimization problem. This general problem is the focus of this article.One of the most important considerations in this framework is whether adaptivity is required for the observations. Adaptive observations introduce blocking or sequential operations in the system whereas nonadaptive observations can be performed in parallel. One of the important questions in this regard is to characterize the benefit of adaptivity for probes and observation.We present general techniques for designing constant factor approximations to the optimal observation schemes for several widely used scheduling and metric objective functions. We show a unifying technique that relates this optimization problem to the outlier version of the corresponding deterministic optimization. By making this connection, our technique shows constant factor upper bounds for the benefit of adaptivity of the observation schemes. We show that while probing yields significant improvement in the objective function, being adaptive about the probing is not beneficial beyond constant factors.
Urban transport and CO2 emissions: some evidence from Chinese cities

This working paper provides a bottom-up estimate of energy use and Green-House Gas (GHG) emissions for the transport sector based on data available at the city and municipal levels. For urban transport in China, GHG emissions primarily consist of carbon dioxide (CO2), so these terms are used interchangeably. Energy use and CO2 emissions are also highly correlated based on the predominance of fossil fuels in transport. A database of self-reported indicators was developed and verified for the fourteen participating cities of the China World Bank-Global Environment Facility (GEF) Urban Transport Partnership Program. Other supplemental sources were also used to enrich the dataset for urban transport and energy analysis, namely the most recent China City Statistical Yearbooks. Beijing and Shanghai were also included where data was available from existing studies given their relevance in broad comparison of Chinese cities. Section two discusses the general demographic and economic trends in the sample of cities that may be influencing the sector. Section three points to stylized facts about the most relevant urban transport demand, supply and performance characteristics in recent years and suggests how they may be driving energy consumption and GHG emissions. Section four is the analysis and forecast of energy use and GHG emissions using the urban transport drivers identified. Finally, general conclusions and next steps are suggested in section five, as well as additional details on the data, methodology, definitions, and a map of China with the seventeen selected cities in the annexes.
To know that we know what we know: perceived knowledge and adolescent sexual risk behavior

Conclusions: Perceived knowledge appears to be a salient correlate of adolescent sexual risk behavior and may be a more powerful antecedent of sexual risk taking behavior than objective knowledge which has not been consistently associated with behavior in previous literature. Health care providers and programs should incorporate the construct of perceived knowledge into their assessments of and interventions targeted at adolescents. (excerpt)
CYCLIC SULFONE-3-CARBOXAMIDES AS NOVEL P2-LIGANDS FOR Ro 31-8959 BASED HIV-1 PROTEASE INHIBITORS.

Cyclic sulfone-3-carboxamides are effective P2-1igands for HIV-1 protease inhibitors. Incorporation of 3S-tetrahydro-2H-thiopyrancarboxamide-l, l-dioxide in the hydroxyethylamine series resulted in inhibitor 14 (IC50=9 nM, CIC95=200 nM) with improved potency compared to its corresponding urethane derivative 18 (IC50=2.0 μM).
Optimized Mask Image Projection for Solid Freeform Fabrication

Solid freeform fabrication (SFF) processes based on mask image projection have the potential to be fast and inexpensive. More and more research and commercial systems have been developed based on these processes. For the SFF processes, the mask image planning is an important process planning step. In this paper, we present an optimization based method for mask image planning. It is based on a light intensity blending technigue called pixel blending. By intelligently controlling pixels' gray scale values, the SFF processes can achieve a much higher XY resolution and accordingly better part quality. We mathematically define the pixel blending problem and discuss its properties. Based on the formulation, we present several optimization models for solving the problem including a mixed-integer programming model, a linear programming model, and a two-stage optimization model. Both simulated and physical experiments for various CAD models are presented to demonstrate the effectiveness and efficiency of our method.
Energy efficient lighting for the biological clock

Unexpectedly the existence of a formerly unknown type of photoreceptor in the human eye has been proven about 10 years ago. Primarily sensitive in the blue spectral range it is responsible for transducing light signals directly into the brain, controlling essential biological functions like setting of the circadian clock or daytime activation. Recent scientific research has enabled beneficial applications. The paradigms for good lighting design are shifting and standardization activities have been started to build up a sound base for description and application of biologically effective lighting. Latest improvements of LED technology are now allowing realizeation of advanced lighting solutions based on SSL. Optimization of biological effects is possible while demands on good vision are maintained. As biologically effective lighting is addressing a second system besides vision in the human body a measure beyond lumen per watt is required for a proper description of energy efficiency.
Chemoenzymatic synthesis of homoazasugars

Abstract A chemoenzymatic approach for the synthesis of homoazasugars is described, utilizing an aldolase to catalyze the key asymmetric aldol addition reaction. This approach is illustrated by the synthesis of β-D-homomannonojirimycin (11) using D-fructose diphosphate (FDP) aldolase.
In Vivo Comparison of Conventional and Cone-Beam CT–Synthesized Cephalograms

Abstract Objective: To compare measurements from synthesized cone-beam computed tomography (CBCT) lateral cephalograms using orthogonal and perspective projections with those from conventional cephalometric radiographs. Materials and Methods: Thirty-one patients were imaged using CBCT and conventional cephalometry. CBCT volume data were imported in Dolphin 3D. Orthogonal and perspective lateral cephalometric radiographs were created from three-dimensional (3D) virtual models. Twelve linear and five angular measurements were made on synthesized and conventional cephalograms in a randomized fashion. Conventional image measurements were corrected for known magnification. Linear and angular measurements were compared between image modalities using repeated measures analysis of variance. Statistical significance was defined as an α level of .01. Results: With the exception of the Frankfort-mandibular plane angle (P .01). Line...
Reducing bandwidth requirement for delivering video over wide area networks with proxy server

Due to the high bandwidth requirement and rate variability of compressed video, delivering video across wide area networks (WANs) is a challenging issue. Proxy servers have been used to reduce network congestion and improve client access time on the Internet by caching passing data. We investigate ways to store or stage partial video in proxy servers to reduce the network bandwidth requirement over WAN. A client needs to access a portion of the video from a proxy server over a local area network (LAN) and the rest from a central server across a WAN. Therefore, client buffer requirement and video synchronization are to be considered. We study the tradeoffs between client buffer, storage requirement on the proxy server, and bandwidth requirement over WAN. Given a video delivery rate for the WAN, we propose several frame staging selection algorithms to determine the video frames to be stored in the proxy server. A scheme called chunk algorithm, which partitions a video into different segments (chunks of frames) with alternating chunks stored in the proxy server, is shown to offer the best tradeoff. We also investigate an efficient way to utilize client buffer when the combination of video streams from WAN and LAN is considered.
Nonclassical Aryl Radicals: Intermediates or Transition States for the Hydrogen Shift Reactions?

Electronic properties of aryl radicals obtained by removing single hydrogen atoms from the sterically congested regions of benzo[c]phenanthrene, biphenyl, triphenylene, phenanthrene, and perylene are studied at the UBLYP/6-311G level of theory. Two structures are considered by each radical, the classical one involving a C-H.C arrangement of atoms and the nonclassical one possessing a three-center C-H-C linkage. The five nonclassical radicals under study are found to be transition states for degenerate 1,4- and 1,5-hydrogen shift reactions that interconvert the classical species. However, the results of the present calculations indicate that the nonclassical structures with the C-H distances in the C-H-C linkages shorter than 1.34 A should be energy minima representing potentially observable chemical systems. The predicted energy barrier to the 1,5-hydrogen shift in the 1-benzo[c]phenanthrenyl radical is only 9.3 kcal/mol (6.1 kcal/mol with the zero-point energies included), making the hydrogen migration in this system facile at relatively low temperatures. Rigorous analysis of the computed electronic wave functions provides a clear-cut picture of bonding in both the classical and nonclassical aryl radicals.
Subset-based training and pruning of sigmoid neural networks

In the present paper we develop two algorithms, subset-based training (SBT) and subset-based training and pruning (SBTP), using the fact that the Jacobian matrices in sigmoid network training problems are usually rank deficient. The weight vectors are divided into two parts during training, according to the Jacobian rank sizes. Both SBT and SBTP are trust-region methods. Compared with the standard Levenberg-Marquardt (LM) method, these two algorithms can achieve similar convergence properties as the LM but with fewer memory requirements. Furthermore the SBTP combines training and pruning of a network into one comprehensive procedure. The effectiveness of the two algorithms is evaluated using three examples. Comparisons are made with some existing algorithms. Some convergence properties of the two algorithms are given to qualitatively evaluate the performance of the algorithms.
Qualitative Behavior of Stochastic Epidemics

Epidemic theory suffers from a great disproportion between the number of parameters which are needed to describe the important phenomena, and the number of parameters which can be estimated from the data. In order to understand the behavior of epidemics, one should take account of effects such as latency periods, variations in infectivity from one individual to another, and complicated mixing structures in the population. On the other hand, complete and reliable data are difficult to obtain. Often, one can at most hope for data on the final size of the epidemic, i. e. the total number of individuals who were infected at some time or other in the history of the epidemic.
Low-Speed Impact Damage-Initiation Characteristics of Selected Laminated Composite Plates

The results of an experimental and analytical study of damage initiation in laminated composite plates subjected to low-speed impact are presented. Here, 8-, 16-, 24-, 32-, and 48-ply-thick quasi-isotropic and orthotropic graphite-epoxy and graphite-bismaleimide laminated plates have been impacted with dropped weights and the corresponding plate responses have been predicted analytically. Impact damage-initiation thresholds and damage-initiation mechanisms corresponding to a range of impact-energy levels are identified. Impact-damage initiation for the thicker plates occurs at both the impact site and the plate surface opposite to the impact site. Impact-damage initiation for the thinner plates is predominately due to tensile fracture on the plate surface opposite to the impact site. Three-dimensional stress states that correspond to the impact conditions that initiate damage are determined analytically to help identify damage-initiation mechanisms and to predict failure-initiation modes.
Modeling Flash Diffusivity Experiments in Two Dimensions for Thick Samples

The laser flash method for measuring thermal diffusivity is well established and has been in use for many years. Early analysis methods employed a simple model, in which one-dimensional transient conduction was assumed, with insulated surfaces during the time subsequent to the flash. More recently, models of greater sophistication have been applied to flash diffusivity experiments using nonlinear regression. The advanced models have achieved highly accurate agreement with experimental data taken from thin samples, on the order of 1 mm in thickness. As samples become thicker, models that neglect edge losses can lose some conformity to the experimental data. The present research involves the application of a two-dimensional model, which allows for penetration of the laser flash into the sample. The accommodation of the flash penetration is important for porous materials, where the coarseness of the porosity is more than 1% of the sample thickness. Variability of the area of incidence of the flash is also investigated to determine the effect on the model and the results. Statistical methods are used in order to make a determination as to the validity of the two-dimensional model, as compared with the one-dimensional analysis method.
Software mutational robustness

Neutral landscapes and mutational robustness are believed to be important enablers of evolvability in biology. We apply these concepts to software, defining mutational robustness to be the fraction of random mutations to program code that leave a program's behavior unchanged. Test cases are used to measure program behavior and mutation operators are taken from earlier work on genetic programming. Although software is often viewed as brittle, with small changes leading to catastrophic changes in behavior, our results show surprising robustness in the face of random software mutations. The paper describes empirical studies of the mutational robustness of 22 programs, including 14 production software projects, the Siemens benchmarks, and four specially constructed programs. We find that over 30 % of random mutations are neutral with respect to their test suite. The results hold across all classes of programs, for mutations at both the source code and assembly instruction levels, across various programming languages, and bear only a limited relation to test suite coverage. We conclude that mutational robustness is an inherent property of software, and that neutral variants (i.e., those that pass the test suite) often fulfill the program's original purpose or specification. Based on these results, we conjecture that neutral mutations can be leveraged as a mechanism for generating software diversity. We demonstrate this idea by generating a population of neutral program variants and showing that the variants automatically repair latent bugs. Neutral landscapes also provide a partial explanation for recent results that use evolutionary computation to automatically repair software bugs.
Retailer price distributions and promotional activities

Abstract An interesting feature of the data is that the price distribution in the absence of promotional activities first order stochastically dominates that under display or feature advertising. The theoretical model we introduce can yield an equilibrium that is consistent with the above observations.
Mid-Infrared Imaging of the Massive Young Star AFGL 2591: Probing the Circumstellar Environment of an Outflow Source

Most, if not all, stars are now believed to produce energetic outflows during their formation. Yet, almost 20 years after the discovery of bipolar outflows from young stars, the origins of this violent phenomenon are not well understood. One of the difficulties of probing the outflow process, particularly in the case of massive embedded stars, is a deficit of high spatial resolution observations. Here we present subarcsecond-resolution mid-infrared images of one massive young stellar object, AFGL 2591, and its immediate surroundings. Our images, at 11.7, 12.5, and 18.0 μm, reveal a knot of emission ≈6'' southwest of the star, which may be evidence for a recent ejection event or an embedded companion star. This knot is roughly coincident with a previously seen near-infrared reflection nebula and a radio source, and it lies within the known large-scale CO outflow. We also find a new faint northwest source that may be another embedded lower luminosity star. The IRAS mid-infrared spectrum of AFGL 2591 shows a large silicate absorption feature at 10 μm, implying that the primary source is surrounded by an optically thick dusty envelope. We discuss the interrelationship of these phenomena and suggest that mid-infrared imaging and spectroscopy provide powerful tools for probing massive star birth.
Profits and halos: The role of firm profitability information in consumer inference

Abstract Three experiments investigated the consequences of the presence of information that a manufacturing firm is profitable on consumers' judgments of the firm and the consequences for perceptions of advertising, products, and choice intention. When profitability is present in the advertising context, consumers form more favorable advertiser judgments, which drive perceptions of greater advertisement credibility, which lead to more favorable product inferences, and ultimately stronger purchase intentions. The third experiment additionally shows that profitability information interacts with a warranty to drive judgments and choice. The implication of our findings is that firms should consider highlighting their profitability to enhance advertising effectiveness.
A Method for Mapping the Temperature Profile of X-Ray Clusters through Radio Observations

Many of the most luminous extragalactic radio sources are located at the centers of X-ray clusters, and so their radiation must be scattered by the surrounding hot gas. We show that radio observations of the highly polarized scattered radiation (which depends on the electron density distribution) in combination with the thermal Sunyaev-Zel'dovich effect (which measures the electron pressure distribution) can be used to determine the radial profile of the electron temperature within the host cluster. The sensitivity levels expected from current instruments will allow radio measurements of mass-weighted cluster temperature profiles to better than a ~1 keV accuracy, as long as the central radio source is steady over several million years. Variable or beamed sources will leave observable signatures in the scattered emission. For clusters with a central point source brighter than ~1 mJy, the scattered polarization signal is stronger than competing effects due to the cosmic microwave background.
Method for mapping charge pulses in semiconductor radiation detectors

Abstract An efficient method for determining the distribution of charge pulses produced by semiconductor detectors is presented. The method is based on a quasi-steady-state model for semiconductor detector operation. A complete description of the model and the underlying assumptions are given. Mapping of charge pulses is accomplished by solving an adjoint carrier continuity equation. The solution of the adjoint equation yields Green's function, a time- and position-dependent map that contains all possible charge pulses that can be produced by the detector for charge generated at discrete locations (e.g., by gamma-ray interactions). Because the map is generated by solving a single, time-dependent problem, the potential for reduction in computational effort over direct mapping methods is significant, particularly for detectors with complex electrode structures. In this paper, the adjoint model is presented and the mapping method is illustrated for a simple case.
Changes in water status during water stress at different stages of development in wheat

The dynamics of stomatal resistance and osmotic adjustment in response to plant water deficits and stage of physiological development was studied in the leaves of spring wheat (Triticum aestivum L., GWO 1809). Plants were germinated and grown in pots in a growth chamber at the Duke University Phytotron to four physiological stages of development (4th leaf, 7th leaf, anthesis, and soft dough), during which time stomatal resistance, total water potential and osmotic potential were measured on the last fully developed leaf of water stressed and non-stressed plants. Pressure potential was obtained by difference. Stomatal closure of the abaxial and adaxial surfaces were independent of each other, each having a different critical total water potential. The total water potential required to close the stomata on the last fully developed leaf were different at different stages of physiological development, decreasing as the plants grew older. The development of osmoregulation in wheat allows the closure of stomata during the vegetative stage at a high total water potential, but insures that stomata remain open from anthesis through the ear filling period to a lower total water potential.
A SIMPLE MODEL FOR THE MOTION OF PULSED-LASER-DRIVEN THIN FLYERS

Abstract - A model that predicts the final velocity of high-power, pulsed-laser- driven thin flyers is described. The required input parameters can either be obtained from standard handbooks or simply extracted from one set of data. The model yields a number of features and scaling laws that are well verified by experiment. Specific comparisons of model predictions with experimental results illustrate excellent agreement for variations of laser fluence and pulse width as well as flyer diameter and thickness. Introduction Previous work 111 has shown that simple models can be used to describe the recoil momentum generated by the explosive vaporization caused by high-power pulsed radiation loads incident on target surfaces (e.g., from lasers). In most earlier investigations the vaporized blowoff products were allowed to expand freely. In the present study, short high-intensity laser pulses are transmitted through fused silica optical fibers onto thin-foil metallic flyers placed on the fiber ends. In this case the blowoff reactions are fully tamped by the fiber, and free expansion does not occur. The configuration is shown schematically in Figure 1. To describe this situation, we have developed a simple model, employing conservation of energy and momentum, in the framework of the well-known Gurney theory for high-explosive-driven plates [2,
Locking out rival bidders: The use of lockup options in corporate mergers

Abstract Conventional wisdom suggests that lockup options are granted by self-interested target managers to discourage competition and hand-select an acquirer, thus harming target shareholder wealth. Evidence from 2,067 deals announced during 1988–1995 suggests that lockup options inhibit competition, but on average, deals with lockup options have higher target announcement and overall returns and lower bidder announcement returns, even after controlling for shareholder anticipation and other factors. An examination of 100 merger proxies suggests lockup options are no more prevalent in privately negotiated, preemptive deals, and average target returns are higher when such deals include a lockup option. The overall evidence is more consistent with managers using lockup options to enhance bargaining power than with lockup options harming shareholder wealth.
Advancing Alpha: Measuring Reliability With Confidence

In this research, we present the inferential statistics for Cronbach's coefficient alpha. This index of reliability is extremely important in consumer research. The estimation of alpha and its confidence intervals are described and an analytical demonstration illustrates the effects on these statistics of their components, including the number of items, the item intercorrelations, and sample size. SAS and SPSS programs are offered for easy implementation. We conclude with a prescription that every time a researcher reports a coefficient alpha, the confidence interval for alpha should accompany the alpha estimate.
The cell adhesion molecule Roughest depends on βHeavy-spectrin during eye morphogenesis in Drosophila

Cell junctions have both structural and morphogenetic roles, and contain complex mixtures of proteins whose interdependencies are still largely unknown. Junctions are also major signaling centers that signify correct integration into a tissue, and modulate cell survival. During Drosophila eye development, the activity of the immunoglobulin cell adhesion molecule Roughest (also known as Irregular chiasm C-roughest protein) mediates interommatidial cell (IOC) reorganization, leading to an apoptotic event that refines the retinal lattice. Roughest and the cadherin-based zonula adherens (ZA) are interdependent and both are modulated by the apical polarity determinant, Crumbs. Here we describe a novel relationship between the Crumbs partner βHeavy-spectrin (βH), the ZA and Roughest. Ectopic expression of the C-terminal segment 33 of βH (βH33) induces defects in retinal morphogenesis, resulting the preferential loss of IOC. This effect is associated with ZA disruption and Roughest displacement. In addition, loss-of-function karst and roughest mutations interact to cause a synergistic and catastrophic effect on retinal development. Finally, we show that βH coimmunoprecipitates with Roughest and that the distribution of Roughest protein is disrupted in karst mutant tissue. These results suggest that the apical spectrin membrane skeleton helps to coordinate the Cadherin-based ZA with Roughest-based morphogenesis.
On the problem of communicating complex information

The nature of the difficulty involved in communicating mathematical results between scientists using a computer based information retrieval system is examined. The problem is analyzed in terms of psychological and information-processing processes, and what turns out to be a vicious circle of effects is described. The paper then considers how the presentation of information by a computer-based information retrieval system, or by other media, can be improved. Some trade-offs which affect the design of the presentation are mentioned, and a number of ideas for improvement are described. These include ways of augmenting written natural language by various notational and linguistic devices, the exhibition of the structure inherent in the information we are communicating, and a sophisticated interactive system controlled by computer.
Computing Economic Chaos

Existence theory in economics is usually in real domains such as the findings of chaotic trajectories in models of economic growth, tâtonnement, or overlapping generations models. Computational examples, however, sometimes converge rapidly to cyclic orbits when in theory they should be nonperiodic almost surely. We explain this anomaly as the result of digital approximation and conclude that both theoretical and numerical behavior can still illuminate essential features of the real data.
Holdups and holdouts: What do they have in common?

Abstract The holdup and holdout problems arise in different contexts, but they share certain fundamental similarities that have not generally been recognized. This paper characterizes the commonalties between the two problems and their remedies.
Characterization and Discrimination of Large Caliber Gun Blast and Flash Signatures

Two hundred and one firings of three 152 mm howitzer munitions were observed to characterize firing signatures of a large caliber gun. Muzzle blast expansion was observed with high-speed (1600 Hz) optical imagery. The trajectory of the blast front was well approximated by a modified point-blast model described by constant rate of energy deposition. Visible and near-infrared (450 - 850 nm) spectra of secondary combustion were acquired at ~0.75 nm spectral resolution and depict strong contaminant emissions including Li, Na, K, Cu, and Ca. The O 2 (X→b) absorption band is evident in the blue wing of the potassium D lines and was used for monocular passive ranging accurate to within 4 - 9%. Timeresolved midwave infrared (1800 - 6000 cm -1 ) spectra were collected at 100 Hz and 32 cm -1 resolution. A low dimensional radiative transfer model was used to characterize plume emissions in terms of area, temperature, soot emissivity, and species concentrations. Combustion emissions have ~100 ms duration, 1200 - 1600 K temperature, and are dominated by H 2 O and CO 2 . Non-combusting plume emissions last ~20 ms, are 850 - 1050 K, and show significant continuum (emissivity ~0.36) and CO structure. Munitions were discriminated with 92 - 96% classification accuracy using only 1 - 3 firing signature features.
Co-Repression of Mismatch Repair Gene Expression by Hypoxia in Cancer Cells: Role of the Myc/Max Network

The key microenvironmental stress of hypoxia is associated with a diverse spectrum of alterations in both the expression and activation patterns of numerous DNA repair and stress-response factors. We have shown previously that hypoxia causes decreased expression of the mismatch repair gene, MLH1, leading to increased genetic instability in tumor cells, although the mechanism remained to be determined. Here we elucidate a mechanism by which MLH1 and another mismatch repair (MMR) gene, MSH2, are repressed by hypoxia. This repression occurs via a dynamic shift in occupancy from activating c-Myc/Max to repressive Mad1/Max and Mnt/Max complexes at the proximal promoters of both the MLH1 and MSH2 genes. Repression of the MMR genes was also seen in both hypoxia-inducible factor (HIF) proficient and deficient cells, and so ruling out an essential role for HIFs in MMR gene expression. These data highlight a novel HIF-independent stress-response pathway induced by hypoxia leading to the coordinated repression of MLH1 and MSH2, key genes in the MMR pathway, and they provide further insight into the possible mechanisms of hypoxia-induced genetic instability and consequent tumor progression in cancer cells.
Alternative regime switching models for forecasting inflation

US inflation appears to undergo shifts in its mean level and variability. We evaluate the performance of three useful models for capturing such shifts. The models studied are the Markov switching models, state space models with heavy-tailed errors, and state space models with compound error distributions. Our study shows that all three models have very similar performance when evaluated in terms of the mean squared or mean absolute forecast errors. However, the latter two models are considerably more parsimonious, and easily beat the more profligately parameterized Markov switching models in terms of model selection criteria, such as the AIC or the SBC. Thus, these may serve as useful continuous alternatives to the popular discrete Markov switching models for capturing shifts in time series. Copyright © 2001 by John Wiley & Sons, Ltd.
Cardiac Alternans Arising From an Unfolded Border-Collision Bifurcation

Following an electrical stimulus, the transmembrane voltage of cardiac tissue rises rapidly and remains at a constant value before returning to the resting value, a phenomenon known as an action potential. When the pacing rate of a periodic train of stimuli is increased above a critical value, the action potential undergoes a period-doubling bifurcation, where the resulting alternation of the action potential duration is known as alternans in medical literature. Existing cardiac models treat alternans either as a smooth or as a border-collision bifurcation. However, recent experiments in paced cardiac tissue reveal that the bifurcation to alternans exhibits hybrid smooth/nonsmooth behaviors, which can be qualitatively described by a model of so-called unfolded border-collision bifurcation. In this paper, we obtain analytical solutions of the unfolded border-collision model and use it to explore the crossover between smooth and nonsmooth behaviors. Our analysis shows that the hybrid smooth/nonsmooth behavior is due to large variations in the system's properties over a small interval of the bifurcation parameter, providing guidance for the development of future models.
Zener tunneling between Landau orbits in a high-mobility two-dimensional electron gas.

Magnetotransport in a laterally confined two-dimensional electron gas (2DEG) can exhibit modified scattering channels owing to a tilted Hall potential. Transitions of electrons between Landau levels with shifted guiding centers can be accomplished through a Zener tunneling mechanism, and make a significant contribution to the magnetoresistance. A remarkable oscillation effect in weak field magnetoresistance has been observed in high-mobility 2DEGs in $\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}\text{\ensuremath{-}}\mathrm{A}\mathrm{l}{\mathrm{G}}_{\mathrm{a}}{\mathrm{A}}_{\mathrm{s}}$ heterostructures, and can be well explained by the Zener mechanism.
RADIAL VELOCITY OFFSETS DUE TO MASS OUTFLOWS AND EXTINCTION IN ACTIVE GALACTIC NUCLEI

We present a study of the radial velocity offsets between narrow emission lines and host galaxy lines (stellar absorption and H I 21 cm emission) in Seyfert galaxies with observed redshifts less than 0.043. We find that 35% of the Seyferts in the sample show [O III] emission lines with blueshifts with respect to their host galaxies exceeding 50 km s–1, whereas only 6% show redshifts this large, in qualitative agreement with most previous studies. We also find that a greater percentage of Seyfert 1 galaxies show blueshifts than Seyfert 2 galaxies. Using Hubble Spce Talescope/Space Telescope Imaging Spectrograph spatially resolved spectra of the Seyfert 2 galaxy NGC 1068 and the Seyfert 1 galaxy NGC 4151, we generate geometric models of their narrow-line regions (NLRs) and inner galactic disks, and show how these models can explain the blueshifted [O III] emission lines in collapsed STIS spectra of these two Seyferts. We conclude that the combination of mass outflow of ionized gas in the NLR and extinction by dust in the inner disk (primarily in the form of dust spirals) is primarily responsible for the velocity offsets in Seyfert galaxies. More exotic explanations are not needed. We discuss the implications of this result for the velocity offsets found in higher redshift active galactic nuclei.
The Validity of the Cosmic String Pattern Search with the Cosmic Microwave Background

We introduce a new technique to detect the discrete temperature steps that cosmic strings might have left in the cosmic microwave background (CMB) anisotropy map. The technique provides a validity test on the pattern search of cosmic strings that could serve as the groundwork for future pattern searches. The detecting power of the technique is only constrained by two unavoidable features of CMB data: (1) the finite pixelization of the sky map and (2) the Gaussian fluctuation from instrumental noise and primordial anisotropy. We set the upper limit on the cosmic string parameter as Gμ 1.6 × 10-5 at the 95% confidence level (CL) and find that the amplitude of the temperature step has to be greater than 44 μK in order to be detected for the Wilkinson Microwave Anisotropy Probe (WMAP) 3 year data.
Fast Fourier Transform for Fitness Landscapes

Abstract We cast some classes of fitness landscapes as problems of spectral analysis on various Cayley graphs. In particular, landscapes derived from RNA folding are realized on Hamming graphs and analyzed in terms of Walsh transforms; assignment problems are interpreted as functions on the symmetric group and analyzed in terms of the representation theory of S n . We show that explicit computation of the Walsh/Fourier transforms is feasible for landscapes with up to 10 8 configurations using fast Fourier transform techniques. We find that the cost function of a linear sum assignment problem involves only the defining representation of the symmetric group, while quadratic assignment problems are superpositions of the representations indexed by the partitions ( n ), ( n −1,1), ( n −2,2), and ( n −2,1,1). These correspond to the four smallest eigenvalues of the Laplacian of the Cayley graph obtained by using transpositions as the generating set on S n .
A new Millimeter-wave printed dipole phased array antenna using microstrip-fed coplanar stripline tee junctions

A new millimeter-wave printed twin dipole phased array antenna is developed at Ka band using a new microstrip-fed CPS tee junction, which does not require any bonding wires, air bridges, or via holes. The phased array used a piezoelectric transducer (PET) controlled tunable multitransmission line phase shifter to accomplish a progressive phase shift. A progressive phase shift of 88.8/spl deg/ is achieved with the 5 mm of perturber length when the PET has full deflection. Measured return loss of the twin dipole antenna is better than 10 dB from 29.5 to 30.35 GHz. Measured return loss of better than 15 dB is achieved from 30 to 31.5 GHz for a 1/spl times/8 phased array. The phased array antenna has a measured antenna gain of 14.4 dBi with 42/spl deg/ beam scanning and has more than 11 dB side lobe suppression across the scan.
Doppler shifted H Ly α Emission from Jupiter's aurora

High-spectral-resolution IUE observations of the aurora on Jupiter were obtained in order to search for Doppler shifted H-Ly-alpha emission produced through charge exchange by fast precipitating protons. Although no emission has been observed corresponding to proton energies greater than 200 eV, a large fraction of the H-Ly-alpha emission has appeared Doppler shifted, mainly toward the blue, by about 50 km/s. These results show that the acceleration of ionospheric plasma in an H2 atmosphere can lead to bright Ly-alpha emission, setting constraints on the production of the outer planet airglow emissions.
Radiation-hardened microelectronics for accelerators

Ionization and displacement phenomena in semiconducting materials are reviewed. How these basic effects lead to changes in the electrical characteristics of transistors and diodes and the functionality of integrated circuits are discussed. The fundamental radiation limits for various semiconductor technologies are summarized. Recommendations and precautions are given regarding the applicability of various microelectronic technologies to different accelerator environments. >
Smart meter privacy: A utility-privacy framework

End-user privacy in smart meter measurements is a well-known challenge in the smart grid. The solutions offered thus far have been tied to specific technologies such as batteries or assumptions on data usage. Existing solutions have also not quantified the loss of benefit (utility) that results from any such privacy-preserving approach. Using tools from information theory, a new framework is presented that abstracts both the privacy and the utility requirements of smart meter data. This leads to a novel privacy-utility tradeoff problem with minimal assumptions that is tractable. Specifically for a stationary Gaussian Markov model of the electricity load, it is shown that the optimal utility-and-privacy preserving solution requires filtering out frequency components that are low in power, and this approach appears to encompass most of the proposed privacy approaches.
Direct observation of Born-Oppenheimer approximation breakdown in carbon nanotubes.

Raman spectra and electrical conductance of individual, pristine, suspended, metallic single-walled carbon nanotubes are measured under applied gate potentials. The G- band is observed to downshift with small applied gate voltages, with the minima occurring at E_F = ±½E_phonon, contrary to adiabatic predictions. A subsequent upshift in the Raman frequency at higher gate voltages results in a “W”-shaped Raman shift profile that agrees well with a nonadiabatic phonon renormalization model. This behavior constitutes the first experimental confirmation of the theoretically predicted breakdown of the Born−Oppenheimer approximation in individual single-walled carbon nanotubes.
A static interpretation of the order-parameters in spin-glasses

The spin-glass phase is described as a statistical mixture of an infinite number of phases. The order-parameters q(x) and Δ(x), with x∈[0,1] measure the correlation between the phases, and the linear response anomaly respectively. Sompolinsky's solution is recovered and reinterpreted Description d'un verre de spin comme un melange statistique d'un nombre infini de phases, les parametres d'ordre q(x) et Δ(x) avec x∈[0,1] mesurant respectivement les correlations entre les phases et l'anomalie de reponse lineaire. Nouvelle discussion de la solution de Sompolinsky ainsi obtenue
Adaptive Lanczos methods for recursive condition estimation

Estimates for the condition number of a matrix are useful in many areas of scientific computing, including: recursive least squares computations, optimization, eigenanalysis, and general nonlinear problems solved by linearization techniques where matrix modification techniques are used. The purpose of this paper is to propose an adaptive Lanczos estimator scheme, which we call ale, for tracking the condition number of the modified matrix over time. Applications to recursive least squares (RLS) computations using the covariance method with sliding data windows are considered. ale is fast for relatively small n - parameter problems arising in RLS methods in control and signal processing, and is adaptive over time, i.e., estimates at time t are used to produce estimates at time t + 1. Comparisons are made with other adaptive and non-adaptive condition estimators for recursive least squares problems. Numerical experiments are reported indicating that ale yields a very accurate recursive condition estimator.