cssi/SciSciGPT-SciSciNet huggingface dataset:
Nickel- vs Palladium-Catalyzed Synthesis of Protected Phenols from Aryl Halides

We report the nickel-catalyzed formation of alkyl and silyl ethers from aryl halides in one step. These ethers can act as precursors to phenols by reaction with Bronsted or Lewis acids or with fluoride. A combination of Ni(COD)2 and DPPF mediates the formation of tert-butyl aryl, methyl aryl, and tert-butyldimethyl silyl aryl ethers efficiently from aryl halides and sodium alkoxides or sodium siloxides under mild reaction conditions. Reactions to form the tert-butyl aryl ethers mediated by nickel complexes have lower turnover numbers than the analogous palladium-catalyzed reactions. However, reactions to form methyl aryl ethers show higher yields when catalyzed by a combination of Ni(COD)2 and BINAP than when catalyzed by BINAP or DPPF and palladium catalyst precursors. Similarly, the formation of silyl aryl ethers occurs in higher yields and under milder conditions when catalyzed by a combination Ni(COD)2 and DPPF than when catalyzed by palladium complexes. We also report improved yields from our previou...
Numerical simulation of thermofluid characteristics of two-phase slug flow in microchannels

A fundamental study of heat transfer characteristics of two-phase slug flow in microchannels is carried out employing the Volume-of-Fluid (VOF) method. Despite of the fact that numerical simulations of two-phase flows in microchannels have been attempted by many investigators, most efforts seem to have failed in correctly capturing the flow physics, especially those pertaining to the slug flow regime characteristics. The presence of a thin liquid film in the order of 10 μm around the bubble is a contributing factor to the above difficulty. Typically, liquid films have a significant effect on the flow field and heat transfer characteristics. In the simulations reported in this paper, the film is successfully captured and a very high local convective heat transfer coefficient is observed in the film region. A strong coupling between the conductive heat transfer in the solid wall and the convective heat transfer in the flow field is observed and characterized. Results showed that unsteady heat transfer through the solid wall in the axial direction is comparable to that in the radial direction. Results also showed that a fully developed condition could be achieved fairly quickly compared to single-phase flows. The fully developed condition is defined based on the Peclet number (Pe) and a dimensionless length of the liquid slug. Local and time-averaged Nusselt numbers for slug flows are reported for the first time. It was found that significant improvements in the heat transfer coefficient could be achieved by short slugs where the Nusselt number was found to be 610% higher than in single-phase flows. The study revealed new findings related to slug flow heat transfer in microchannels with constant wall heat flux.
Authority and Communication in Organizations

This paper studies delegation as an alternative to communication. We show that a principal prefers to delegate control to a better informed agent rather than to communicate with this agent as long as the incentive conflict is not too large relative to the principal's uncertainty about the environment. We further identify cases in which the principal optimally delegates control to an "intermediary", and show that keeping a veto-right typically reduces the expected utility of the principal unless the incentive conflict is extreme. This paper is concerned with the old saying that "knowledge is power". In organizations, much of the information used in decision making is dispersed in the hierarchy. Lower-level managers, for example, are often much better informed about consumer needs, competitive pressures, specialized technologies or market opportunities than their superiors. The financial press is full of stories about how companies have pushed decision rights lower in the hierarchy in order to profit from this local knowledge.1 For the same reason, newly acquired subsidiaries are often left with substantial autonomy. The goal of this paper is to better understand why an uninformed principal (the company owners, senior management) may grant formal decision rights to an agent (senior or middle management) who is better informed but has different objectives. We argue that a principal often delegates authority in order to avoid the noisy communication, and hence the loss of information, which stems from these differences in objectives.
Vibrations of sessile drops of soft hydrogels

Abstract Sessile drops of soft hydrogels were vibrated vertically by subjecting them to a mechanically-induced Gaussian white noise. Power spectra of the surface fluctuation of the gel allowed identification of its resonant frequency that decreases with their mass, but increases with its shear modulus ( μ ) . The principal resonant frequencies of the spheroidal modes of the gel of shear moduli ranging from 55 Pa to 290 Pa were closest to the lowest Rayleigh mode of vibration of a drop of pure water. These observations coupled with the fact that the resonance frequency varies inversely as the mass with an exponent close to 0.5 suggest that they primarily correspond to the capillary (or a pseudo-capillary) mode of drop vibration. The contact angles of the gel drops also increase with the modulus of the gel. When the resonance frequencies are plotted against a fundamental frequency scale ( γ / ρ P 2 h ) 0.5 (expressed in terms of its surface tension ( γ ) , density ( ρ ) , perimeter ( P ) and mean thickness ( h ) ) all the data collapse nicely on a single plot provided that the latter is shifted by a shear modulus dependent factor ( 1 + μ h / 2 γ ) . We believe that this method has the potential to measure directly the surface tension of soft elastic gels.
High-energy emission from pulsars: The Polar cap scenario

Abstract The study of pulsars in the three and a half decades since their discovery has highlighted a handful of issues critical to their understanding. To date there is no consensus on the physical mechanism for their radio emission, despite a rapid increase in the observed population due to the Parkes multi-beam survey and prospects for similar growth in the radio population database in the near future. The small subset of pulsars that emit at X-ray to γ-ray wavelengths is critical to refining the pulsar paradigm, since this energy band (i) is where the vast majority of radiative luminosity is observed and (ii) is intimately connected to the pair winds that form the dominant mode of energy deposition in the circum-pulsar environment. The most crucial point of contention pertaining to the high energy astrophysics of pulsars is the location of the acceleration region in their magnetospheres: is an outer gap model or a polar cap scenario (or both) the most appropriate picture. Radiative signatures provide the clues to this current enigma. This review focuses on salient characteristics of the polar cap scenario; these form the basis for discriminating observational diagnostics that should drive pulsars studies in the GLAST era just three years away.
Efficiency outcomes of market concentration and managed care

Abstract The paper examines how hospital cost efficiency has reacted to extensive horizontal integrations of hospitals and rapid growth of managed care in the US health care industry. Cost efficiency is estimated by using panel data approaches to relax the assumptions for the hospital effects imposed in earlier studies. The paper shows that higher managed care penetration over time is associated with greater hospital efficiency, and higher market concentration is positively associated with efficiency when markets are highly competitive or highly concentrated.
Intramolecular donor–acceptor cyclopropane ring-opening cyclizations

Cyclization reactions of donor–acceptor (D–A) cyclopropanes are recognized as versatile methods for construction of carbocyclic and heterocyclic scaffolds. In the literature, many examples of these polarized cyclopropanes' reactivity with nucleophiles, electrophiles, and radicals are prevalent. Although intermolecular reactivity of donor–acceptor cyclopropanes is widely reported, reviews that center on their intramolecular chemistry are rare. Thereupon, this tutorial review focalizes on new intramolecular transformations of donor–acceptor cyclopropanes for cycloisomerizations, formal cycloadditions, umpolung reactions, rearrangements and ring-opening lactonizations/lactamizations from 2009 to 2013. Furthermore, the role of D–A acceptor cyclopropanes as reactive subunits in natural product synthesis is underscored.
Au42: an alternative icosahedral golden fullerene cage.

We present a new icosahedral gold fullerene, Au42, based on density functional theory calculations. The Au42 fullerene has a nanoscale hollow space that can hold up to 13 Au atoms. The Au42 fullerene also has a larger HOMO−LUMO gap compared to the compact-filling geometries. However, unlike the known gold fullerene Au32, the Au42 fullerene does not satisfy the 2(N + 1)2 aromatic rule and has a positive NICS value at the center of the cage. These two nanometer-sized gold fullerenes can be used as golden cages to accommodate other atoms or molecules for the purpose of studying fundamental chemistry because of their apparently dissimilar chemical characteristics, or they can be used as structural motifs to build highly stable core−shell nanoclusters or novel cluster-assembled materials.
An Algebraic Cell Decomposition of the Nonnegative Part of a Flag Variety

Abstract We study the nonnegative part B ≥ 0of the flag variety B of a reductive algebraic group, as defined by Lusztig. Using positivity properties of the canonical basis it is shown that B ≥ 0has an algebraic cell decomposition indexed by pairs of elementsw ≤ w′ of the Weyl group. This result was conjectured by G. Lusztig (1994,in“Progr. Math.,” Vol. 123, pp. 531–568, Birkhauser, Basel).
The Paradoxical Nature of Nursing Research

The following article was presented originally as a paper at the 11th annual WICHEN Communicating Research Conference on May 5, 1978 at Portland, Oregon. Editors of Image found it a forthright and challenging personal testimonial to the paradoxical nature of nursing research and decided it should have broader distribution. The paper has been edited for publication.
Response of self-excited oscillators to multifrequency excitations

Abstract The method of multiple scales is used to determine the response of a self-excited system having a single degree of freedom to multi-frequency harmonic excitations. Many cases, including combination and simultaneous resonances, are considered. The perturbation results are found to be in good agreement with those obtained by numerically integrating the governing differential equation. The response consists of two parts—a forced oscillation part and a free oscillation part with an amplitude and phase that are functions of the excitations. The results show that there exist conditions under which the free oscillation part can be quenched. The steady state response is not periodic unless the excitation is periodic. It is found that the presence of non-resonant excitations may suppress the free oscillation part.
Distribution of injected power fluctuations in electroconvection.

We report on the distribution spectra of the fluctations in the amount of power injected into a liquid crystal undergoing electroconvective flow. The probability distribution functions (PDFs) of the fluctuations as well as the magnitude of the fluctuations have been determined in a wide range of imposed stress both for unconfined and confined flow geometries. These spectra are compared to those found in other systems held far from equilibrium, and find that in certain conditions we obtain the universal PDF form reported by S.T. Bramwell et al. [Phys. Rev. Lett. 84, 3744 (2000)]. Moreover, the PDF approaches this universal form via an interesting mechanism whereby the distribution's negative tail evolves towards form in a different manner than the positive tail.
THE EFFECT OF SELF-TENDER OFFERS ON EARNINGS EXPECTATIONS

We examine financial analysts' earnings revisions after self-tender offers. Consistent with the assertions of earlier studies that self-tender offers signal future performance, financial analysts significantly increase their forecasts of earnings for firms that announce self-tender offers. However, the revisions differ based on the method chosen to repurchase shares. For Dutch auction offers, analysts significantly revise their estimates of short-term earnings only. For fixed-price tender offers, analysts increase both short-term and long-term earnings estimates. Also, long-term earnings revisions are significantly related to announcement-period abnormal returns for fixed-price tender offers, which suggests that fixed-price self-tender offers convey more positive information about future earnings than do Dutch auction offers.
HYBRID LIQUID CRYSTAL LIGHT VALVE -IMAGE TUBE DEVICES FOR OPTICAL DATA PROCESSING

We report here the feasibility of coupling an image intensifier tube directly with the ac liquid crystal light valve, which is briefly described and characterized in the paper, to form a compact, real-time, incoherent-to-coherent image converter. This hybrid device is capable of sensing image intensity levels of less than 10-6 In addition, the same combination can be used as an image amplifier with an intensity gain of up to 10. In the experiments performed we mated an 18 mm aperture micro-channel plate inten-sifier image tube, with a fiber optic faceplate output, with a 50 mm aperture hybrid field effect liquid crystal that has a fiber optic faceplate input. With an incoherent input image intensity of 3 x 10 ft-candle we observed a limiting resolution of 16 1P/mm in the output coherent image. This resolution limit is determined primarily by the image intensifier tube. MTF data for the hybrid device and the components are also presented, along with a photograph of gray scale image capability. The use of other types of image intensifier tubes, such as those having image storage capability, with the light valve is discussed and performance ranges given. Next we summarize the possible uses of the hybrid device to increase the usefulness of real-time optical data processing. Finally, we describe the application of this device to wavelength conversion and image amplification to provide the large screen projection of dynamic ac plasma panel display imagery.© (1977) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
2,6-DIMETHOXYPHENYLPHOSPHETANE SULFIDE SYNTHESIS, STRUCTURE AND EXPLORATORY PHOTOCHEMISTRY

Abstract 2,6-Dimethoxyphenylphosphetane sulfide has been synthesized by condensation of 2,6-dimethoxyphenylphosphine with 1,3-propanediol ditosylate and treatment of the resulting phosphetane with sulfur. Irradiation at 254 nm of the phosphetane sulfide was undertaken to determine the mode of photodissociation and the types of reactive intermediates produced. Evidence is presented for the formation of both the corresponding arylphosphinidene sulfide ArPS and the methylene(thioxo)phosphorane ArP(S)CH2 as transient species.
Adaptive Pneumatic Force Actuation and Position Control

In this paper an implementation of an adaptive control law for a pneumatic actuator is presented. Pneumatic actuators are of particular interest for robotic applications because of their large force output per unit weight, and their low cost. Stabilization of a pneumatic actuator is difficult if a high bandwidth closed-loop system is desired. This is because of the compressibility of air, and of the nonlinear characteristics of air flowing through a variable area orifice. Further complications arise from the geometry of the mechanism because the equations of motion are highly nonlinear. The order of the dominant dynamics is shown to vary with the position of the mechanism.
Optimal space-time packet scheduling for reservation ALOHA networks

This paper studies the packet scheduling problem for S-TDMA wireless networks employing reservation ALOHA. Under the criterion of maximum channel throughput, the mathematical model of the optimal scheduling is introduced. A simple greedy algorithm is proposed to solve the NP-hard optimization problem.
Uniform exponential energy decay of Euler-Bernoulli equations by suitable boundary feedback operators

The author sketches the proof of a few novel results on uniform stabilization of Euler-Bernoulli equations. The results are fully consistent with recently established exact controllability and optimal regularity theories. A bending moment type of condition replaces the Neumann boundary condition. The author presents results for the case in which only the boundary control is active. As expected, geometrical conditions on the domain are needed. >
Gain scheduling dynamic linear controllers for a nonlinear plant

Abstract For a general type of nonlinear tracking problem, we consider gain scheduling based on a family of linear dynamic controllers designed for a family of plant linearizations about constant operating points. A necessary and sufficient condition for the existence of gain scheduled controllers satisfying appropriate requirements is presented. Using this condition, the impact of linear controller configuration on the existence of a gain scheduled controller can be assessed, and ad hoc approaches to scheduling can be analyzed.
How Much Should We Trust Differences-In-Differences Estimates?

Most papers that employ Differences-in-Differences estimation (DD) use many years of data and focus on serially correlated outcomes but ignore that the resulting standard errors are inconsistent. To illustrate the severity of this issue, we randomly generate placebo laws in state-level data on female wages from the Current Population Survey. For each law, we use OLS to compute the DD estimate of its “effect” as well as the standard error of this estimate. These conventional DD standard errors severely understate the standard deviation of the estimators: we find an “effect” significant at the 5 percent level for up to 45 percent of the placebo interventions. We use Monte Carlo simulations to investigate how well existing methods help solve this problem. Econometric corrections that place a specific parametric form on the time-series process do not perform well. Bootstrap (taking into account the autocorrelation of the data) works well when the number of states is large enough. Two corrections based on asymptotic approximation of the variance-covariance matrix work well for moderate numbers of states and one correction that collapses the time series information into a “pre”- and “post”-period and explicitly takes into account the effective sample size works well even for small numbers of states.
Synthesis and conformational properties of N-monoalkyl 1,5-diaza-cis-decalins

Abstract N-Monoalkyl 1,5-diaza-cis-decalins were synthesized in high yield and purity by derivatization of tetrahydronaphthyridine followed by reduction to the saturated system. The position of the conformational equilibrium between the chair–chair inversion forms of a series of four N-monoalkyl of 1,5-diaza-cis-decalins was measured and was directly related to the size of the N-alkyl group.
Organ Preservation Approaches With Radiation Therapy in Muscle-Invasive Bladder Carcinoma

Combined modality treatments with organ preservation intent have become standard oncological treatment in many tumour sites. Although radical cystectomy had been considered to be the standard treatment, combined modality treatment has been used in muscle-invasive bladder carcinoma with excellent results, especially in patients with T2-3a disease without obstructed ureters. The components of the combined treatment are usually transurethral resection of bladder tumour (TURBT) followed by concurrent chemotherapy and radiation. Interim cystoscopic assessment after the initial portion of radiation is often utilised to identify patients at high risk of local failure, ie. those who do not achieve a complete response, and these patients are then recommended to undergo immediate salvage cystectomy. Delaying cystectomy does not appear to decrease the survival or increase the incidence of distant metastasis. The local control rates for TURBT alone, chemotherapy alone and radiation therapy alone are only 20%, 20% and 30% to 45% respectively. When the above three are combined together, a complete response rate of 75% can be achieved and 85% of these remain free from invasive recurrence. Combined modality treatment offers an overall survival rates which is comparable with modern radical cystectomy series: about 50% at 5 years, and in addition, it offers a 5-year survival rate with an intact bladder of 41% to 43%. With the close collaboration among urologists, medical oncologists and radiation oncologists, organ preservation approaches can achieve excellent results in muscle-invasive bladder carcinoma and this option should be presented to patients as an alternative to radical cystectomy.
Automorphic distributions, L-functions, and Voronoi summation for GL(3)

This paper is third in a series of three, following "Summation Formulas, from Poisson and Voronoi to the Present" (math.NT/0304187) and "Distributions and Analytic Continuation of Dirichlet Series" (math.FA/0403030). The first is primarily an expository paper explaining the present one, whereas the second contains some distributional machinery used here as well. These papers concern the boundary distributions of automorphic forms, and how they can be applied to study questions about cusp forms on semisimple Lie groups. The main result of this paper is a Voronoi-style summation formula for the Fourier coefficients of a cusp form on GL(3,Z)\GL(3,R). We also give a treatment of the standard L-function on GL(3), focusing on the archimedean analysis as performed using distributions. Finally a new proof is given of the GL(3)xGL(1) converse theorem of Jacquet, Piatetski-Shapiro, and Shalika. This paper is also related to the later papers math.NT/0402382 and math.NT/0404521.
Knowledge technology through functional layered intelligence

The Internet and other various networks are growing into an interconnection environment of information pools that is often overwhelming. Knowledge technology has been developing intensively, however with limited success: the concepts such as knowledge, information, and data are still amorphous; limitations are re-confirmed in the predominant formalist-reductionist model and lack of organic attributes; there is a lack of coordination and interoperability. These issues are reviewed here over many prominent knowledge technology efforts. An architecture reference model called Functional Layered Intelligence (FLI) is also introduced as a solutions framework. Knowledge technology is then presented as a subset of the FLI model.
A quantitative analysis of body mass index and colorectal cancer: findings from 56 observational studies.

To perform a systematic review of studies reporting on the association between body mass index (BMI) and the risk of colorectal cancer, we conducted a meta-analysis and meta-regression analysis. The identified 56 studies were conducted among 7 213 335 individuals including 93 812 cases. Compared with BMI or = 30.0 kg m(-2) were associated with 14%, 19%, 24% and 41% increased risks, respectively. Asians and premenopausal women had sharply increased risk from BMI < 23 kg m(-2) to general 'normal' range (23-25 kg m(-2)). Each 5 kg m(-2) increment was associated with 18% increased risk. Meta-regression analysis indicated that the association was stronger for colon than rectal cancer (P < 0.001), for men than women (P < 0.001), for self-reported BMI than directly measured BMI (P < 0.001), and for studies adjusting for physical activity than not adjusting (P < 0.001). The variation of the reported risk estimates for the association can be partly explained by cancer site, sex, women menopausal status, BMI assessment and adjustment of confounding variables.
The effect of dedicated methodology and statistical review on published manuscript quality

Abstract Study objective: We examine how dedicated methodology and statistical review affects the quality of manuscripts published in Annals of Emergency Medicine. Design: The dedicated reviewers developed a manuscript scoring form based on previously used instruments. The form contained 84 unique elements. Eight items sought the presence of state-of-the-art features (eg, formal exploration of the sensitivity of results to assumptions); the others sought substandard quality. Two raters independently scored each original research publication appearing in 4 consecutive issues of Annals for the presence or absence of each relevant item. We then reviewed the formal methodology and statistical review and all subsequent correspondence between authors and editors to determine whether the methodology and statistical review provided guidance regarding each of the 84 items and whether the advice was incorporated into the final manuscript. Results: There were 32 original research articles. One was never subjected to methodology and statistical review. Reviewers agreed on 94% of all items; single-item agreement ranged from 77% to 100%. State-of-the-art features were present in 31 (14%) of 217 ratings; the methodology and statistical review had commented on 13 (42%) of these. State-of-the-art features were absent in 186 (86%) ratings; the methodology and statistical review had commented on 33 (18%) of these. Substandard features were deemed present in 166 (12%) of 1,519 ratings; the methodology and statistical review had commented on 82 (44%) of these. Substandard features were absent in 1,333 (88%) ratings; the methodology and statistical review had commented on 132 (10%) of these. We found no fatal flaws in the published manuscripts. Conclusion: Methodology reviewers often failed to comment on deficiencies that they had classified as substandard when designing this study. Reviews also did not encourage inclusion of state-of-the-art abstract, article, and references features. When reviews identified areas in need of improvement, only half of the comments led to improved manuscripts. In the other half, authors either rebuked the suggestions or the editors did not act when suggestions were ignored. [ Ann Emerg Med. 2002;40:334-337.]
Automated computation of arbor densities: a step toward identifying neuronal cell types

The shape and position of a neuron convey information regarding its molecular and functional identity. The identification of cell types from structure, a classic method, relies on the time-consuming step of arbor tracing. However, as genetic tools and imaging methods make data-driven approaches to neuronal circuit analysis feasible, the need for automated processing increases. Here, we first establish that mouse retinal ganglion cell types can be as precise about distributing their arbor volumes across the inner plexiform layer as they are about distributing the skeletons of the arbors. Then, we describe an automated approach to computing the spatial distribution of the dendritic arbors, or arbor density, with respect to a global depth coordinate based on this observation. Our method involves three-dimensional reconstruction of neuronal arbors by a supervised machine learning algorithm, post-processing of the enhanced stacks to remove somata and isolate the neuron of interest, and registration of neurons to each other using automatically detected arbors of the starburst amacrine interneurons as fiducial markers. In principle, this method could be generalizable to other structures of the CNS, provided that they allow sparse labeling of the cells and contain a reliable axis of spatial reference.
Indian Ocean intraseasonal sea surface temperature variability during boreal summer: Madden‐Julian Oscillation versus submonthly forcing and processes

[1] Intraseasonal sea surface temperature (SST) variability in the Indian Ocean during boreal summer is investigated with a series of experiments using the Hybrid Coordinate Ocean Model (HYCOM). QuickSCAT winds and satellite-observed outgoing longwave radiation (OLR) are used to identify the wind and convection patterns associated with atmospheric intraseasonal oscillations (ISOs). Effects of the Madden-Julian Oscillation (MJO; 30–90 days) and submonthly ISOs are separately examined. Similar to winter, MJO forcing dominates summertime SST variability, even though submonthly forcing is stronger. Wind plays a much larger role in altering SSTs than either shortwave fluxes or precipitation. Different from winter cases, the maximum summertime SST variability shifts to the Arabian Sea (AS) and the Bay of Bengal (BOB), when ISOs also shift to the Northern Hemisphere. In the BOB, surface heat fluxes due to changes in wind speed have a stronger influence on SST than upwelling and advection induced by wind stress, whereas in winter, the effects of surface heat fluxes and oceanic upwelling and advection are comparable. This difference arises from the barrier layer and thin surface mixed layer in the BOB, which reduce the effects of upwelling and amplify the effects of surface heat fluxes. In the AS, surface heat fluxes and entrainment cooling due to changes in wind speed have a larger effect on MJO-scale SST than upwelling induced by wind stress, while the two have comparable effects on submonthly SST. In the equatorial region, wind speed and stress are equally important.
On stationary oscillations of galaxies

This paper describes a general investigation of stationary oscillations of galaxies. It begins with a linear analysis of modes of oscillation with continuous spectra of real frequencies. Such modes are gravitational analogues of the van Kampen modes of oscillation in plasmas. The characteristic value problem governing modes of the van Kampen type in a galaxy is solved with the aid of a modified version of the matrix method of Kalnajs in which the perturbation of the distribution function is expressed in terms of generalized functions. In general, there is no characteristic equation governing the frequencies in the continuous spectrum. However, isolated frequencies in the continuous spectrum do satisfy a characteristic equation, which, for stellar systems, is a counterpart of the dispersion relation proposed by Vlasov for plasma oscillations. The linear analysis also provides a characteristic equation for modes with a discrete spectrum of real and/or complex frequencies. The second part of the paper describes a perturbation theory for a stationary oscillation of a galaxy with a small but finite amplitude. Integrals of the stellar motion are constructed with the aid of canonical perturbation theory and used in conjunction with Jeans' theorem to specify the density of stars in the six-dimensional phase space. These oscillations are slightly non-linear counterparts of the modes of the van Kampen type, and they are stellar-dynamical counterparts of the non-linear plasma waves described by Bernstein, Greene and Kruskal in the 1950s. Fully non-linear models of stationary oscillations of galaxies can be constructed with the aid of Schwarzschild's numerical method for the solution of the fundamental integral equation describing the self-consistency of a stellar system.
High-Pressure Turbine Deposition in Land-Based Gas Turbines From Various Synfuels

Ash deposits from four candidate power turbine synfuels were studied in an accelerated deposition test facility. The facility matches the gas temperature and velocity of modern first stage high pressure turbine vanes. A natural-gas combustor was seeded with finely-ground fuel ash particulate from four different fuels: straw, sawdust, coal, and petroleum coke. The entrained ash particles were accelerated to a combustor exit flow Mach number of 0.31 before impinging on a thermal barrier coating (TBC) target coupon at 1150°C. Post exposure analyses included surface topography, scanning electron microscopy, and x-ray spectroscopy. Due to significant differences in the chemical composition of the various fuel ash samples, deposit thickness and structure vary considerably for each fuel. Biomass products (e.g. sawdust and straw) are significantly less prone to deposition than coal and petcoke for the same particle loading conditions. In a test simulating one turbine operating year at a moderate particulate loading of 0.02 parts per million by weight, deposit thickness from coal and petcoke ash exceeded 1 mm and 2 mm respectively. These large deposits from coal and petcoke were found to detach readily from the turbine material with thermal cycling and handling. The smaller biomass deposit samples showed greater tenacity in adhering to the TBC surface. In all cases, corrosive elements (e.g. Na, K, V, Cl, S) were found to penetrate the TBC layer during the accelerated deposition test. Implications for the power generation goal of fuel flexibility are discussed. [Keywords: deposition, syngas, turbines] NOMENCLATURE ESEM environmental scanning electron microscope TBC thermal barrier coating
Neuroeconomics: cross-currents in research on decision-making

Despite substantial advances, the question of how we make decisions and judgments continues to pose important challenges for scientific research. Historically, different disciplines have approached this problem using different techniques and assumptions, with few unifying efforts made. However, the field of neuroeconomics has recently emerged as an inter-disciplinary effort to bridge this gap. Research in neuroscience and psychology has begun to investigate neural bases of decision predictability and value, central parameters in the economic theory of expected utility. Economics, in turn, is being increasingly influenced by a multiple-systems approach to decision-making, a perspective strongly rooted in psychology and neuroscience. The integration of these disparate theoretical approaches and methodologies offers exciting potential for the construction of more accurate models of decision-making.
Discreteness of area and volume in quantum gravity

We study the operator that corresponds to the measurement of volume, in non-perturbative quantum gravity, and we compute its spectrum. The operator is constructed in the loop representation, via a regularization procedure; it is finite, background independent, and diffeomorphism-invariant, and therefore well defined on the space of diffeomorphism invariant states (knot states). We find that the spectrum of the volume of any physical region is discrete. A family of eigenstates are in one to one correspondence with the spin networks, which were introduced by Penrose in a different context. We compute the corresponding component of the spectrum, and exhibit the eigenvalues explicitly. The other eigenstates are related to a generalization of the spin networks, and their eigenvalues can be computed by diagonalizing finite dimensional matrices. Furthermore, we show that the eigenstates of the volume diagonalize also the area operator. We argue that the spectra of volume and area determined here can be considered as predictions of the loop-representation formulation of quantum gravity on the outcomes of (hypothetical) Planck-scale sensitive measurements of the geometry of space.
Reduction of wave drag by antisymmetric arrangement of wings and bodies.

The wave interference effects for bodies or wings in a mirror-symmetric arrangement, and in an antisymmetric arrangement are discussed. It is shown that while in the case of a mirror-symmetric arrangement large adverse interference effects can be observed, antisymmetric arrangements provide comparatively much smaller wave drags. The single continuous wing panels also adapt themselves more readily to varying angles of obliquity, and hence, to varying flight speeds. A detailed review is presented of the previous work on the aerodynamic properties and flight stability of oblique elliptic wing combinations. A possible mode of application of these combinations to transport aircraft operating at moderate supersonic speeds is suggested.
The Forward Exchange Market, Speculation, and Exchange Market Intervention

This paper examines two issues. The first is the role of speculation in stabilizing the economy against stochastic disturbances. Increased speculation (i) stabilizes domestic income against disturbances in the domestic bond market and forward exchange market; (ii) exacerbates the effect of foreign disturbances; and (iii) may dampen or augment the effect of money market and output supply disturbances. The second issue is the role of the forward market in stabilization policy. Forward market intervention does not provide monetary authorities additional leverage in stabilizing income beyond unsterilized spot market intervention. Intervention rules based on reactions to both the forward and the spot exchange rates, however, can outperform intervention policies responding to the spot rate alone, regardless of the market in which intervention occurs.
Cellular FLICE-Like Inhibitory Protein (C-FLIP): A Novel Target for Cancer Therapy

Cellular FLICE-like inhibitory protein (c-FLIP) has been identified as a protease-dead, procaspase-8-like regulator of death ligand-induced apoptosis, based on observations that c-FLIP impedes tumor necrosis factor-α (TNF-α), Fas-L, and TNF-related apoptosis- inducing ligand (TRAIL)-induced apoptosis by binding to FADD and/or caspase-8 or -10 in a ligand-dependent fashion, which in turn prevents death-inducing signaling complex (DISC) formation and subsequent activation of the caspase cascade. c-FLIP is a family of alternatively spliced variants, and primarily exists as long (c-FLIPL) and short (c-FLIPS) splice variants in human cells. Although c-FLIP has apoptogenic activity in some cell contexts, which is currently attributed to heterodimerization with caspase-8 at the DISC, accumulating evidence indicates an anti-apoptotic role for c-FLIP in various types of human cancers. For example, small interfering RNAs (siRNAs) that specifically knocked down expression of c-FLIPL in diverse human cancer cell lines, e.g., lung and cervical cancer cells, augmented TRAIL-induced DISC recruitment, and thereby enhanced effector caspase stimulation and apoptosis. Therefore, the outlook for the therapeutic index of c-FLIP-targeted drugs appears excellent, not only from the efficacy observed in experimental models of cancer therapy, but also because the current understanding of dual c-FLIP action in normal tissues supports the notion that c-FLIP-targeted cancer therapy will be well tolerated. Interestingly, Taxol, TRAIL, as well as several classes of small molecules induce c-FLIP downregulation in neoplastic cells. Efforts are underway to develop small-molecule drugs that induce c-FLIP downregulation and other c- FLIP-targeted cancer therapies. In this review, we assess the outlook for improving cancer therapy through c-FLIP-targeted therapeutics.
Performance evaluation of error recovery schemes in high speed networks

Error control in high-speed communication networks is usually applied either as a link-by-link scheme or as an end-to-end scheme. The authors propose analytic performance models for comparing the performance of the link-by-link and end-to-end approaches with respect to error control. The models consider the effects of packet error rate, propagation delays of messages, separate virtual-circuit finite buffers, and timeout mechanisms. It is shown that the average end-to-end packet delay is affected by the packet error rate, the buffer size, the number of hops along the virtual-circuit, the traffic along the virtual circuit, and the processing overhead in the link layer. Thus, in a high-speed, low-error rate, optical-fiber network, the end-to-end error-recovery scheme can achieve shorter average end-to-end packet delay. >
Exact covariance thresholding into connected components for large-scale graphical lasso

We consider the sparse inverse covariance regularization problem or graphical lasso with regularization parameter λ. Suppose the sample covariance graph formed by thresholding the entries of the sample covariance matrix at λ is decomposed into connected components. We show that the vertex-partition induced by the connected components of the thresholded sample covariance graph (at λ) is exactly equal to that induced by the connected components of the estimated concentration graph, obtained by solving the graphical lasso problem for the same λ. This characterizes a very interesting property of a path of graphical lasso solutions. Furthermore, this simple rule, when used as a wrapper around existing algorithms for the graphical lasso, leads to enormous performance gains. For a range of values of λ, our proposal splits a large graphical lasso problem into smaller tractable problems, making it possible to solve an otherwise infeasible large-scale problem. We illustrate the graceful scalability of our proposal via synthetic and real-life microarray examples.
Pentaquark Searches at CDF

Recently there has been revival of interest in exotic baryon spectroscopy triggered by experimental evidence for pentaquarks containing u, d, s and c-quarks. They report results of the searches for pentaquark states in decays to pK{sub S}{sup 0}, {Xi}{sup -} {pi}{sup {+-}} and D*{sup -} p performed at CDF detector using 220 pb{sup -1} sample of p{bar p} interactions at {radical}s of 1.96 TeV. No evidence for narrow resonances were found in either mode.
Wind Modeling and Lateral Control for Automatic Landing

For the purposes of aircraft control system design and analysis, the wind can be characterized by a mean com- ponent which varies with height and by turbulent components which are described by the von Karman correlation model. The aircraft aerodynamic forces and moments depend linearly on uniform and gradient gust components obtained by averaging over the aircraft's length and span. The correlations of the averaged com- ponents are then approximated by the outputs of linear shaping filters forced by white noise. The resulting model of the crosswind shear and turbulence effects is used in the design of a lateral control system for the automatic landing of a DC-8 aircraft. NE of the more challenging problems facing an autopilot designer is the synthesis of feedback logic which will achieve the desired attitude and position of an aircraft at touchdown in the presence of turbulent crosswinds. During the approach phase of an automatic landing, the desired flight path is maintained by heading slightly into the prevailing crosswind ("crabbing"). However, at touchdown, the aircraft centerline must be aligned with the runway to prevent lateral skidding of the wheels on the landing gear. The transition from the approach attitude to the touchdown attitude, termed the "decrab maneuver," is usually carried out by the pilot, using the rudder to reduce the heading deviation, and ailerons to dip the windward wing tip sightly so as to maintain the lateral position in the presence of the resulting aerodynamic sideslip. When visibility is reduced to the point where the pilot cannot maintain the required visual reference, it is desirable to perform the decrab maneuver automatically. In order to carry out an effective automatic landing, ac- curate information on the aircraft's attitude and position is required. In the last several years, accurate and reliable navigation systems have been developed to provide this in- formation. Such systems include inertially augmented ILS systems,1'2 microwave landing systems, MLS,3 and various attitude reference systems.4 It is anticipated that further im- provements in system accuracy and reliability will be made in the future. Touchdown errors in automatic landing are also caused by turbulent winds. In contrast with the navigation errors, there is little hope of reducing these disturbances. In fact, as lan- ding speeds are lowered, as in STOL aircraft applications, the wind effects become more pronounced.
The social discount rate : estimates for nine Latin American countries

The social discount rate measures the rate at which a society would be willing to trade present for future consumption. As such it is one of the most critical inputs needed for cost-benefit analysis. This paper presents estimates of the social discount rates for nine Latin American countries. It is argued that if the recent track record in terms of growth in the region is indicative of future performance, estimates of the social discount rate would be in the 3-4 percent range. However, to the extent that the region improves on its past performance, the social discount rate to be used in the evaluation of projects would increase to the 5-7 percent range. The paper also argues that if the social planner gives a similar chance to the low and high growth scenario, the discount rate should be dependent on the horizon of the project, declining from 4.4 percent for a 25-year horizon to less than 4 percent for a 100-year horizon.
Power Requirements for Large-Amplitude Flapping Flight

In this paper, a method is presented for computing the circulation distribution along the span of a e apping wing that minimizes the power required to generate a prescribed lift and thrust. The power is composed of three parts: useful thrust power, induced power, and proe le power. Here, the thrust and induced power are expressed in terms of the Kelvin impulse and kinetic energy associated with the sheet of trailing and shed vorticity left behind the e apping wing. The proe le power is computed using a quasisteady approximation of the two-dimensional viscous drag polar at each spanwise station of the wing. A variational principle is then formed to determine the necessary conditions for the circulation distribution to be optimal. Included in the variational principle is a constraint that the wing not stall. This variational principle, which is essentially the viscous extension of the well-known Betz criterion for optimal propellers, is discretized using a vortex-lattice model of the wake, and the optimum solution is computed numerically. The present method is used to analyze a conventional propeller as well as a rigid wing in forward-e ight e apping about a hinge point on the longitudinal axis.
A general study of the influence of catastrophic photometric redshift errors on cosmology with cosmic shear tomography

A goal of forthcoming imaging surveys is to use weak gravitational lensing shear measurements to constrain dark energy. A challenge to this program is that redshifts to the lensed, source galaxies must be determined using photometric, rather than spectroscopic, information. We quantify the importance of uncalibrated photometric redshift outliers to the dark energy goals of forthcoming imaging surveys in a manner that does not assume any particular photometric redshift technique or template. In so doing, we provide an approximate blueprint for computing the influence of specific outlier populations on dark energy constraints. We find that outlier populations whose photo-z distributions are tightly localized about a significantly biased redshift must be controlled to a per-galaxy rate of (1-3) × 10–3 to insure that systematic errors on dark energy parameters are rendered negligible. In the complementary limit, a subset of imaged galaxies with uncalibrated photometric redshifts distributed over a broad range must be limited to fewer than a per-galaxy error rate of F cat (2-4) × 10–4. Additionally, we explore the relative importance of calibrating the photo-z's of a core set of relatively well-understood galaxies as compared to the need to identify potential catastrophic photo-z outliers. We discuss the degradation of the statistical constraints on dark energy parameters induced by excising source galaxies at high- and low-photometric redshifts, concluding that removing galaxies with photometric redshifts z ph 2.4 and z ph 0.3 may mitigate damaging catastrophic redshift outliers at a relatively small (20%) cost in statistical error. In an Appendix, we show that forecasts for the degradation in dark energy parameter constraints due to uncertain photometric redshifts depend sensitively on the treatment of the nonlinear matter power spectrum. In particular, previous work using Peacock & Dodds may have overestimated the photo-z calibration requirements of future surveys.