cssi/SciSciGPT-SciSciNet huggingface dataset:
Organic insulators and the copper stabilizer for fusion reactor magnets

Abstract The materials which compose the large composite superconducting fusion reactor magnets are subjected to mechanical stress, neutron and gamma-ray radiation with broad energy spectra, high magnetic fields, and thermal cycling from 4 to 300 K. Of the materials now considered for use in the magnets, results show that the organic insulators and the Cu stabilizer are the most sensitive to this environment. In response to the need for stabilizer data, magnetoresistivity changes were studied in eight variously prepared specimens of Cu throughout five cycles of an alternate neutron irradiation (4.0 K) and annealing (14 h at 307 K) program. The results were combined with those on the radiation behaviour of epoxy and polyimide organic insulators to provide a preliminary assessment of their comparative radiation resistance in a typical magnet location of the Experimental Power Reactor (EPR). It was found that insofar as the chosen conditions typify the mix of gamma-ray and neutron dose rates in fusion reactor magnet locations, the radiation resistance of the stabilizer is at best equal to that of the epoxies and much less than that of the polyimides. The poor performance of the Cu stabilizer suggests that additional shielding for magnet protection or serious magnet design changes are needed. Several needs for further organic insulator and stabilizer research are described.
Demand elasticities for fresh fruit at the retail level

The obesity epidemic in the US and elsewhere has re-doubled efforts to understand determinants of the quality of consumers’ diets. Part of the discussion has centered on the potential of ‘fat taxes’ and/or the subsidization of the purchase of fresh fruits and vegetables to coax consumers to better diets. Whether this discussion has merit or not, fundamental to the debate are the demand elasticities of the commodities involved. This study employs weekly data from several retail stores on fruit prices and sales to estimate elasticities of individual fruits. Estimates show consumers are more responsive to price than has been found previously.
ON THE NONSYMMETRIC PURELY AFFINE GRAVITY

We review the vacuum purely affine gravity with the nonsymmetric connection and metric. We also examine dynamical effects of the second Ricci tensor and covariant second-rank tensors constructed from the torsion tensor in the gravitational Lagrangian.
A review of charm semileptonic decays

Several high energy experiments have been actively pursuing the analyzes of semileptonic decays of charm mesons, resulting in numerous new results and publications. In this report, we summarize the recent efforts on the topics of pseudoscalar and vector charm semileptonic decays, especially in the area of branching fractions and form factor measurements.
The Psychopathology and Treatment of Bipolar Disorder

In this chapter we review research on the diagnosis, course, etiology, and pharmacological and psychosocial treatment of bipolar disorder (BD). BD is a highly recurrent and severe illness, with high rates of suicidality and functional impairment. The disorder is heritable and appears to share susceptibility genes with schizophrenia. It is characterized by dysregulation in the dopamine and serotonin systems and by pathology in the brain systems involved in regulating emotion. Psychosocial stressors, notably life events and familial expressed emotion, significantly influence the course of the illness in the context of these vulnerabilities. Findings of randomized clinical trials indicate that psychosocial interventions enhance long-term outcomes when added to pharmacotherapy. Much remains to be clarified about the interactive contributions of genetic, neurobiological, and psychosocial factors to the course of the disorder, and the moderators and mediators of treatment effects.
X-ray reflectivity studies of atomic-level surface-segregation in a liquid eutectic alloy of AuSn

X-ray reflectivity studies reveal atomic-level surface-segregation at the free surface of the eutectic ${\mathrm{Au}}_{71}{\mathrm{Sn}}_{29}$ liquid alloy. The surface-segregation extends up to three layers, in which the top layer is almost a pure monolayer of Sn, the second layer is almost a pure monolayer of Au and the third layer appears to be slightly enhanced in Au. Although the surface-segregation concentration profiles can be qualitatively accounted for by the theories of Defay-Prigogine and Strohl-King, they cannot satisfactorily account for the measured surface tension.
Centroid-based summarization of multiple documents: sentence extraction, utility-based evaluation, and user studies

We present a multi-document summarizer, called MEAD, which generates summaries using cluster centroids produced by a topic detection and tracking system. We also describe two new techniques, based on sentence utility and subsumption, which we have applied to the evaluation of both single and multiple document summaries. Finally, we describe two user studies that test our models of multi-document summarization.
Reliability-Based Design Optimization of Robotic System Dynamic Performance

In this investigation a robotic system's dynamic performance is optimized for high reliability under uncertainty. The dynamic capability equations (DCE) allow designers to predict the dynamic performance of a robotic system for a particular configuration and reference point on the end effector (i.e., point design). Here the DCE are used in conjunction with a reliability-based design optimization (RBDO) strategy in order to obtain designs with robust dynamic performance with respect to the end-effector reference point. In this work a unilevel performance measure approach is used to perform RBDO. This is important for the reliable design of robotic systems in which a solution to the DCE is required for each constraint call. The method is illustrated on a robot design problem.
VLSI-Architectures for Computer Graphics

Both academic researchers and commercial concerns are increasingly interested in applying VLSI technologies to graphics systems: For researchers, graphics systems offer an attractive model for study of computer architectures in VLSI: these systems have a small well-defined set of operations and simple data and control structures, making these systems ripe for applying parallelism and modularization techniques; many of these systems, especially the interactive high-resolution color ones, have severe computation demands that are unfulfilled by solutions embodied in current systems. For commercial concerns, there is a rapidly increasing market for interactive graphics systems as personal workstations in which graphics displays replace text-only terminals. In this paper, we cover: a) the conceptual organization of a “generic” graphics system and its realization in several state-of-the-art commercial products; b) the architecture of several recent VLSI chips and systems and their likely effect on the organization of future graphics systems; c) the architecture of several VLSI-based systems that are currently subjects of research. The design strategies used in these systems — the structure of parallelism, intertwining of data and computation, the tradeoff between custom and off-the-shelf parts — may provide insights into other applications as well.
Inverse scattering, the coupling constant spectrum, and the Riemann hypothesis

It is well known that the s-wave Jost function for a potential, λV, is an entire function of λ with an infinite number of zeros extending to infinity. For a repulsive V, and at zero energy, these zeros of the ‘coupling constant’, λ, will all be real and negative, λn(0)<0. By rescaling λ, such that λn<−1/4, and changing variables to s, with λ=s(s−1), it follows that as a function of s the Jost function has only zeros on the line sn=1/2+iγn. Thus, finding a repulsive V whose coupling constant spectrum coincides with the Riemann zeros will establish the Riemann hypothesis, but this will be a very difficult and unguided search.
The Merger in Abell 576: A Line-of-Sight Bullet Cluster?

Using a combination of Chandra and XMM-Newton observations, we confirmed the presence of a significant velocity gradient along the northeast-southwest direction in the intracluster gas of the cluster Abell 576. The results are consistent with a previous ASCA SIS analysis of this cluster. The error-weighted average over the ACIS-S3 and EPIC MOS1 and MOS2 spectrometers for the maximum velocity difference is >3.3 × 103 km s-1 at the 90% confidence level, similar to the velocity limits estimated indirectly for the Bullet Cluster (1E 0657-56). The probability that the velocity gradient is generated by standard random gain fluctuations with Chandra and XMM-Newton is <0.1%. The regions of maximum velocity gradient are in CCD zones that have the lowest temporal gain variations. It is unlikely that the velocity gradient is due to Hubble distance differences between projected clusters (probability 0.01%). We mapped the distribution of elemental abundance ratios across the cluster and detected a strong chemical discontinuity using the abundance ratio of silicon to iron, equivalent to a variation from 100% SN Ia iron mass fraction in the west-northwest regions to 32% in the eastern region. The "center" of the cluster is located at the chemical discontinuity boundary, which is inconsistent with the radially symmetric chemical gradient found in some regular clusters, but consistent with a cluster merging scenario. We predict that the velocity gradient as measured will produce a variation of the cosmic microwave background (CMB) temperature toward the east of the core of the cluster that will be detectable by current and near-future bolometers. The measured velocity gradient opens up the possibility that this cluster is passing through a near line-of-sight merger stage where the cores have recently crossed.
IMF conditionality and objections: The Russian case

Emerging economies in crisis typically request assistance from the International Monetary Fund (IMF). After evaluating the situation, the IMF makes a loan available to the country, conditional on certain policy reforms. Governments usually resist many of these measures and negotiation ensues. This paper analyzes the most contentious measures of IMF conditionality in the context of Russia after the August 1998 crisis. The most discussed measures include the budget deficit, structural reforms, and exchange rate policy. Our analysis suggests that to some extent the disagreement arose because the IMF is focused on changing steady states somewhat ignoring the transition path, while the Russian government is preoccupied with transitional dynamics without a clearly defined steady state concept
Facile synthesis of 1-substituted 4,5-diaminopyrazoles and its application toward the synthesis of pyrazolo[3,4-b]pyrazines

Abstract 1-Substituted 5-aminopyrazole-4-carbonylazides were prepared from the appropriate 5-aminopyrazole-4-carboxylates. The acyl azides undergo a Curtius rearrangement followed by quenching with alcohols to form the corresponding carbamates. The 1-substituted 5-amino-4-benzyloxycarbonylaminopyrazoles were unblocked by catalytic hydrogenolysis to give the desired 4,5-diaminopyrazoles. These 4,5-diaminopyrazoles were immediately condensed with glyoxal to afford 1-substituted pyrazolo[3,4- b ]pyrazines.
Concerning the Equation of State for a Partially Ionized System

I will discuss the expansion of various thermodynamic quantities about the ideal gas in powers of the electric charge, and I will discuss some cellular models. The first type of cellular model is appropriate for hydrogen. The second type is for Z > 1. It has the independent electron approximation within the atoms. These models are cross compared and minimal regions of validity are determined. The actual region of validity is expected to be larger. In the cellular models, the phase boundaries for liquid-gas transitions are found. For the second type of cellular model, in the part of the low-temperature, low-density region where there is not much expectation of validity of these methods, a non-thermodynamic region is found. I have devised a construction, similar in spirit to the Maxwell construction, to bridge this region so as to leave a thermodynamically valid equation of state. The non-thermodynamic region does not occur in hydrogen and it seems to be due to the inadequacy of the aforementioned approximation in that region.
Automorphic forms and cohomology theories on Shimura curves of small discriminant

Abstract We apply Lurie's theorem to produce spectra associated to 1-dimensional formal group laws on the Shimura curves of discriminants 6, 10, and 14. We compute rings of automorphic forms on these curves and the homotopy of the associated spectra. At p = 3 , we find that the curve of discriminant 10 recovers much the same as the topological modular forms spectrum, and the curve of discriminant 14 gives rise to a model of a truncated Brown–Peterson spectrum as an E ∞ ring spectrum.
Computing the complete CS decomposition

An algorithm for computing the complete CS decomposition of a partitioned unitary matrix is developed. Although the existence of the CS decomposition (CSD) has been recognized since 1977, prior algorithms compute only a reduced version. This reduced version, which might be called a 2-by-1 CSD, is equivalent to two simultaneous singular value decompositions. The algorithm presented in this article computes the complete 2-by-2 CSD, which requires the simultaneous diagonalization of all four blocks of a unitary matrix partitioned into a 2-by-2 block structure. The algorithm appears to be the only fully specified algorithm available. The computation occurs in two phases. In the first phase, the unitary matrix is reduced to bidiagonal block form, as described by Sutton and Edelman. In the second phase, the blocks are simultaneously diagonalized using techniques from bidiagonal SVD algorithms of Golub, Kahan, Reinsch, and Demmel. The algorithm has a number of desirable numerical features.
Self-referenced prism deflection measurement schemes with microradian precision

We have demonstrated several inexpensive methods that can be used to measure the deflection angles of prisms with microradian precision. The methods are self-referenced, where various reversals are used to achieve absolute measurements without the need of a reference prism or any expensive precision components other than the prisms under test. These techniques are based on laser interferometry and have been used in our laboratory to characterize parallel-plate beam splitters, penta prisms, right-angle prisms, and corner cube reflectors using only components typically available in an optics laboratory.
Algebraic Density Property of Homogeneous Spaces

Let X be an affine algebraic variety with a transitive action of the algebraic automorphism group. Suppose that X is equipped with several fixed point free nondegenerate SL2-actions satisfying some mild additional assumption. Then we prove that the Lie algebra generated by completely integrable algebraic vector fields on X coincides with the space of all algebraic vector fields. In particular, we show that apart from a few exceptions this fact is true for any homogeneous space of form G/R where G is a linear algebraic group and R is a closed proper reductive subgroup of G.
Synthesis, Structure, and Magnetic Properties of the Rare-Earth Zintl Compounds Eu14MnPn11 and Eu14InPn11 (Pn = Sb, Bi)

New rare-earth transition-metal compounds Eu14MnPn11 and Eu14InPn11 (Pn = Sb, Bi) have been prepared in quantitative yield from heating stoichiometric amounts of the elements, which are sealed in a welded tantalum tube that is enclosed in a fused silica ampule, at 950−1200 °C. These compounds are isostructural with the Zintl compound Ca14AlSb11 and crystallize in the tetragonal space group I41/acd (Z = 8). Single-crystal X-ray data (143 K) were refined for Eu14InSb11 (a = 17.280 (5) A, c = 23.129 (8) A, R1 = 4.04%, wR2 = 8.65%) and Eu14MnBi11 (a = 17.632 (4) A, c = 23.047(6) A, R1 = 4.53%, wR2 = 7.83%). The structures of these compounds are compared with Eu14MnSb11 and other compounds of this structure type. Magnetization measurements show that Eu14MnSb11 and Eu14MnBi11 order at approximately 100 and 35 K, respectively. The effective moment in the paramagnetic state for Eu14MnSb11 is μeff = 27.0(1) μB and for Eu14MnBi11 is μeff = 27.1(1) μB. Eu14MnSb11 saturates with μsat = 102 μB at 5 K whereas Eu14MnBi1...
Non‐linear galaxy power spectrum and cosmological parameters

The galaxy power spectrum is now a well-known tool of precision cosmology. In addition to the overall shape, baryon oscillations and the small-scale suppression of power by massive neutrinos capture complementary information on cosmological parameters when compared with the angular power spectrum of cosmic microwave background anisotropies. We study both the real-space and redshift-space galaxy power spectra in the context of non-linear effects, and model them based on the halo approach to large-scale structure clustering. We consider potential systematics in the cosmological parameter determination when non-linear effects are ignored and the galaxy power spectrum is described with the linear power spectrum scaled by a constant bias factor. We suggest that significant improvements can be made when non-linear effects are taken into account as a power-law contribution with two additional parameters to be determined from the data. In addition to cosmological parameters through galaxy clustering, such an approach allows a determination of useful information related to astrophysics on how galaxies occupy dark matter haloes.
An evaluation of User-Level Failure Mitigation support in MPI

As the scale of computing platforms becomes increasingly extreme, the requirements for application fault tolerance are increasing as well. Techniques to address this problem by improving the resilience of algorithms have been developed, but they currently receive no support from the programming model, and without such support, they are bound to fail. This paper discusses the failure-free overhead and recovery impact of the user-level failure mitigation proposal presented in the MPI Forum. Experiments demonstrate that fault-aware MPI has little or no impact on performance for a range of applications, and produces satisfactory recovery times when there are failures.
X-band HBT VCO with high-efficiency CB buffer amplifier

A monolithic AlGaAs-GaAs HBT VCO with common-base (CB) buffer amplifier was demonstrated at X-band. Overall efficiency of 30% was achieved with 93-mW output power at 9.8 GHz. The MMIC chip is only 1 mm*2 mm, including the monolithic varactor diode. The circuit design offers several unique advantages: (1) the CB buffer amplifier reduces the frequency-pull effect from the external load; (2) the design for the oscillation condition and the output impedance match for power are separated; and (3) the overall efficiency can be high. A step-by-step design procedure is discussed. >
Forest phenology and a warmer climate – growing season extension in relation to climatic provenance

Predicting forest responses to warming climates relies on assumptions about niche and temperature sensitivity that remain largely untested. Observational studies have related current and historical temperatures to phenological shifts, but experimental evidence is sparse, particularly for autumn responses. A 4 year field experiment exposed four deciduous forest species from contrasting climates (Liquidambar styraciflua, Quercus rubra, Populus grandidentata, and Betula alleghaniensis) to air temperatures 2 and 4 °C above ambient controls, using temperature-controlled open top chambers. Impacts of year-round warming on bud burst (BB), senescence, and abscission were evaluated in relation to thermal provenance. Leaves emerged earlier in all species by an average of 4–9 days at +2 °C and 6–14 days at +4 °C. Magnitude of advance varied with species and year, but was larger for the first 2 °C increment than for the second. Effect of warming increased with early BB, favoring Liquidambar, but even BB of northern species advanced, despite temperatures exceeding those of the realized niche. Treatment differences in BB were inadequately explained by temperature sums alone. In autumn, chlorophyll was retained an average of 4 and 7 days longer in +2 and +4 °C treatments, respectively, and abscission delayed by 8 and 13 days. Growing seasons in the warmer atmospheres averaged 5–18 days (E2) and 6–28 days (E4) longer, according to species, with the least impact in Quercus. Results are compared with a 16 years record of canopy onset and offset in a nearby upland deciduous forest, where BB showed similar responsiveness to spring temperatures (2–4 days °C−1). Offset dates in the stand tracked August–September temperatures, except when late summer drought caused premature senescence. The common garden-like experiment provides evidence that warming alone extends the growing season, at both ends, even if stand-level impacts may be complicated by variation in other environmental factors.
Performance modeling in the design process

Performance modeling and analysis of computer systems are often ignored during the project design phase in favor of other techniques collectively known as structured design or software engineering. We describe benefits that can result from including performance analysis as an integral part of the design process. Several different goals, time frames, and roles played by performance analysis during system design are illustrated by three case studies of current projects at Los Alamos.
Diels–Alder Reactions of 1,2‐Azaborines

Diels-Alder reactions employing 1,2-azaborine heterocycles as 1,3-dienes are reported. Carbocyclic compounds with high stereochemical and functional complexity are produced, as exemplified by the straightforward two-step synthesis of an amino allyl boronic ester bearing four contiguous stereocenters as a single diastereomer. Whereas electron-deficient dienophiles undergo irreversible Diels-Alder reactions, a reversible Diels-Alder reaction with the less electron-deficient methyl acrylate is observed. Both the N and the B substituent of the 1,2-azaborine exert significant influence on the [4+2] cycloaddition reactivity as well as the aromatic character of the heterocycle. The experimentally determined thermodynamic parameters of the reversible Diels-Alder reaction between 1,2-azaborines and methyl acrylate correlate with aromaticity trends and place 1,2-azaborines approximately between furan and thiophene on the aromaticity scale.
Comparison of Phase Velocities from Array Measurements of Rayleigh Waves Associated with Microtremor and Results Calculated from Borehole Shear-Wave Velocity Profiles

Shear-wave velocities (VS) are widely used for earthquake ground- motion site characterization. VS data are now largely obtained using borehole meth- ods. Drilling holes, however, is expensive. Nonintrusive surface methods are inex- pensive for obtaining VS information, but not many comparisons with direct borehole measurements have been published. Because different assumptions are used in data interpretation of each surface method and public safety is involved in site character- ization for engineering structures, it is important to validate the surface methods by additional comparisons with borehole measurements. We compare results obtained from a particular surface method (array measurement of surface waves associated with microtremor) with results obtained from borehole methods. Using a 10-element nested-triangular array of 100-m aperture, we measured surface-wave phase veloci- ties at two California sites, Garner Valley near Hemet and Hollister Municipal Air- port. The Garner Valley site is located at an ancient lake bed where water-saturated sediment overlies decomposed granite on top of granite bedrock. Our array was deployed at a location where seismic velocities had been determined to a depth of 500 m by borehole methods. At Hollister, where the near-surface sediment consists of clay, sand, and gravel, we determined phase velocities using an array located close to a 60-m deep borehole where downhole velocity logs already exist. Because we want to assess the measurements uncomplicated by uncertainties introduced by the inversion process, we compare our phase-velocity results with the borehole VS depth profile by calculating fundamental-mode Rayleigh-wave phase velocities from an earth model constructed from the borehole data. For wavelengths less than 2 times of the array aperture at Garner Valley, phase-velocity results from array measure- ments agree with the calculated Rayleigh-wave velocities to better than 11%. Mea- surement errors become larger for wavelengths 2 times greater than the array aper- ture. At Hollister, the measured phase velocity at 3.9 Hz (near the upper edge of the microtremor frequency band) is within 20% of the calculated Rayleigh-wave veloc- ity. Because shear-wave velocity is the predominant factor controlling Rayleigh- wave phase velocities, the comparisons suggest that this nonintrusive method can provide VS information adequate for ground-motion estimation.
Schwarzschild black hole surrounded by quintessence: null geodesics

We have studied the null geodesics of the Schwarzschild black hole surrounded by quintessence matter. Quintessence matter is a candidate for dark energy. Here, we have done a detailed analysis of the geodesics and exact solutions are presented in terms of Jacobi-elliptic integrals for all possible energy and angular momentum of the photons. The circular orbits of the photons are studied in detail. As an application of the null geodesics, the angle of deflection of the photons are computed.
Assessing the application of SeaWiFS ocean color algorithms to Lake Erie

The feasibility of satellite-based monitoring of phytoplankton chlorophyll a concentrations in Lake Erie is assessed by applying globally calibrated, ocean-derived color algorithms to spatially and temporally collocated measurements of SeaWiFS remote sensing reflectance. Satellite-based chlorophyll a retrievals were compared with fluorescence-based measurements of chlorophyll a from 68 field samples collected across the lake between 1998 and 2002. Twelve ocean-derived color algorithms, one regional algorithm derived for the Baltic Sea's Case 2 waters, and a set of regional algorithms developed for the western, central and eastern basins of Lake Erie were considered. While none of the ocean-derived algorithms performed adequately, the outlook for the success of regionally calibrated and validated algorithms, with forms similar to the ocean-derived algorithms, is promising over the eastern basin and possibly the central basin of the lake. In the western basin, each of the regional algorithms considered performed poorly, indicating that alternative approaches to algorithm development, or to satellite data screening and analysis procedures will be needed.
Initial Systematic Investigations of the Landscape of Low-Layer NAHE Variation Extensions

The discovery that the number of physically consistent string vacua is on the order of 10500 has prompted several statistical studies of string phenomenology. Focusing on the Weakly Coupled Free Fermionic String formalism, we present systematic extensions of a variation on the NAHE (Nanopoulos, Antoniadis, Hagelin, Ellis) set of basis vectors. This variation is more conducive to the production of “mirrored” models, in which the observable and hidden sector gauge groups (and possibly matter content) are identical. This study is parallel to the extensions of the NAHE set itself and presents statistics related to similar model properties. Statistical coupling between specific gauge groups and spacetime supersymmetry is also examined. Finally, a model with completely mirrored gauge groups is discussed. It is found that the region of the landscape explored generates no physically realistic models due to a lack of three net chiral generations.
Fertility and Modernity

We investigate the historical dynamics of the decline in fertility in Europe and its relation to measures of cultural and ancestral distance. We test the hypothesis that the decline of fertility was associated with the diusion of social and behavioral changes from France, in contrast with the spread of the Industrial Revolution, where England played a leading role. We argue that the diusion of the fertility decline and the spread of industrialization followed dierent patterns because societies at dierent relative distances from the respective innovators (the French and the English) faced dierent barriers to imitation and adoption, and such barriers were lower for societies that were historically and culturally closer to the innovators. We provide a model of fertility choices in which the transition from higher to lower levels of fertility is the outcome of a process of social innovation and social in‡uence, whereby late adopters observe and learn about the novel behaviors, norms and practices introduced by early adopters at the frontier. In the empirical analysis we study the determinants of marital fertility in a sample of European populations and regions from 1830 to 1970, and successfully test our theoretical predictions using measures of genetic distance between European populations and a novel data set of ancestral linguistic distances between European regions.
Water Modeled As an Intermediate Element between Carbon and Silicon

Water and silicon are chemically dissimilar substances with common physical properties. Their liquids display a temperature of maximum density, increased diffusivity on compression, and they form tetrahedral crystals and tetrahedral amorphous phases. The common feature to water, silicon, and carbon is the formation of tetrahedrally coordinated units. We exploit these similarities to develop a coarse-grained model of water (mW) that is essentially an atom with tetrahedrality intermediate between carbon and silicon. mW mimics the hydrogen-bonded structure of water through the introduction of a nonbond angular dependent term that encourages tetrahedral configurations. The model departs from the prevailing paradigm in water modeling: the use of long-ranged forces (electrostatics) to produce short-ranged (hydrogen-bonded) structure. mW has only short-range interactions yet it reproduces the energetics, density and structure of liquid water, and its anomalies and phase transitions with comparable or better accu...
N-Heterocyclic Carbene-Catalyzed Enantioselective Mannich Reactions with α-Aryloxyacetaldehydes

N-Heterocyclic carbenes (NHCs) catalyze a new Mannich-type reaction to form β-amino acid derivatives in high yield and enantioselectivity. The reaction is initiated by the addition of an NHC to an α-aryloxyaldehyde followed by elimination of a phenoxide anion which generates an enol/enolate. A Mannich addition to a tosylimine proceeds with excellent control over enantioselectivity. In a new carbene catalysis concept, catalyst regeneration is promoted by return, or rebound, and acylation of the phenoxide group which served as the activating component in the first step of the catalytic cycle. The activated ester products formed in situ are manipulated to form a variety of useful compounds including β-amino acids, β-amino amides, and peptides.
Weak gravitational lensing by dark clusters

We calculate the abundance of dark matter concentrations that are sufficiently overdense to produce a detectable weak-gravitational-lensing signal. Most of these overdensities are virialized haloes containing identifiable X-ray and/or optical clusters. However, a significant fraction are non-virialized, cluster-mass overdensities still in the process of gravitational collapse - these should produce significantly weaker or no X-ray emission. Our predicted abundance of such dark clusters is consistent with the abundance implied by the detection by Erben et al. of an apparent dark lens. Weak lensing by these non-virialized objects will need to be considered when determining cosmological parameters with the lens abundance in future weak-lensing surveys. Such weak lenses should also help shed light on the process of cluster formation.
LEAST SQUARES ESTIMATION OF A SHIFT IN LINEAR PROCESSES

This paper considers a mean shift with an unknown shift point in a linear process and estimates the unknown shift point (change point) by the method of least squares. Pre-shift and post-shift means are estimated concurrently with the change point. The consistency and the rate of convergence for the estimated change point are established. The asymptotic distribution for the change point estimator is obtained when the magnitude of shift is small. It is shown that serial correlation affects the variance of the change point estimator via the sum of the coefficients (impulses) of the linear process. When the underlying process is an ARMA, a mean shift causes overestimation of its order. A simple procedure is suggested to mitigate the bias in order estimation.
Confronting the Coffee Crisis: Can Fair Trade, Organic, and Specialty Coffees Reduce Small-Scale Farmer Vulnerability in Northern Nicaragua?

This paper links changing global coffee markets to opportunities and vulnerabilities for sustaining small-scale farmer livelihoods in northern Nicaragua. Changing governance structures, corporate concentration, oversupply, interchangeable commodity grade beans, and low farm gate prices characterize the crisis in conventional coffee markets. In contrast, certified Fair Trade and organic are two alternative forms of specialty coffee trade and production that may offer opportunities for small-scale producers. A research team surveyed 228 farmers to measure the impact of sales on organic and Fair Trade markets. The results suggest that participation in organic and Fair Trade networks reduces farmers’ livelihood vulnerability.
Forecasting a Coronal Mass Ejection's Altered Trajectory: ForeCAT

To predict whether a coronal mass ejection (CME) will impact Earth, the effects of the background on the CME's trajectory must be taken into account. We develop a model, ForeCAT (Forecasting a CME's Altered Trajectory), of CME deflection due to magnetic forces. ForeCAT includes CME expansion, a three-part propagation model, and the effects of drag on the CME's deflection. Given the background solar wind conditions, the launch site of the CME, and the properties of the CME (mass, final propagation speed, initial radius, and initial magnetic strength), ForeCAT predicts the deflection of the CME. Two different magnetic backgrounds are considered: a scaled background based on type II radio burst profiles and a potential field source surface (PFSS) background. For a scaled background where the CME is launched from an active region located between a coronal hole and streamer region, the strong magnetic gradients cause a deflection of 8. Degree-Sign 1 in latitude and 26. Degree-Sign 4 in longitude for a 10{sup 15} g CME propagating out to 1 AU. Using the PFSS background, which captures the variation of the streamer belt (SB) position with height, leads to a deflection of 1. Degree-Sign 6 in latitude and 4. Degree-Sign 1 inmore » longitude for the control case. Varying the CME's input parameters within observed ranges leads to the majority of CMEs reaching the SB within the first few solar radii. For these specific backgrounds, the SB acts like a potential well that forces the CME into an equilibrium angular position.« less
An optical communication design laboratory

A senior-level design laboratory course is described, in which an optical fiber communication network is expanded or improved by successive generations of students. In this evolutionary approach, student teams base their work on the final written reports of students in previous course offerings. In addition to its primary goal of providing a high-level technical experience, the course requires multidisciplinary teamwork and provides incentive for the development of effective oral and written communication skills. Results of four offerings of the course are presented.
Some Aspects of the Thermal Design of Electronic Equipment Operating at 300-500&#176;C Environmental Temperature

Summary--Aspects of electronic part-cooling techniques applicable to 300-500°C equipments are presented. Contrary to some beliefs, the minimization of thermal resistance at these temperatures is as important as at lower temperatures. The significant shifts in the natural modes of heat transfer which occur with high-temperature electronic parts are outlined, together with some recommended methods of cooling high-temperature parts and assemblies.
How Fragile Is Africa's Recent Growth?

Has Africa finally reached the path to sustained growth? We find that much of the improvement in economic performance in Africa after 1995 is attributable to a substantial reduction in the frequency and severity of growth declines in all economies and an increase in growth accelerations in mineral-rich economies. We find, however, that growth accelerations have not been generally accompanied by improvements in variables often correlated with long run growth, such as investment. We also fail to find evidence that substantial policy and governance improvements were associated with the post-1995 accelerations. We conclude that Africa’s growth recovery remains fragile.
Research progress in MIS: the Center for Research on Information Systems: New York University

A review is presented of some of the issues involved in establishing a research center and defining its goals viz-a-viz individual faculty goals. The organization and activities of the Center for Research in Information Systems (CRIS) at New York University are described. With this as background, the authors describe some of the research that has been conducted at CRIS and outline current projects and future research directions. >
Economic Determinants of the Nominal Treasury Yield Curve

Abstract Macroeconomic shocks account for most of the variability of nominal Treasury yields, inducing parallel shifts in the level of the yield curve. We develop a new approach to identifying macroeconomic shocks that exploits model-based empirical shock measures. Technology shocks shift yields through their effect on expected inflation and the term premium. Shocks to preferences for current consumption affect yields through their impact on real rates and expected inflation. For both shocks, the systematic reaction of monetary policy is an important transmission pathway. We find little evidence that fiscal policy shocks are an important source of interest rate variability.
Capturing CFLs with Tree Adjoining Grammars

We define a decidable class of TAGs that is strongly equivalent to CFGs and is cubic-time parsable. This class serves to lexicalize CFGs in the same manner as the LCFGs of Schabes and Waters but with considerably less restriction on the form of the grammars. The class provides a normal form for TAGs that generate local sets in much the same way that regular grammars provide a normal form for CFGs that generate regular sets.
Overweight Is Risking Fate

In this paper I have defined obesity and indicated its prevalence, as well as its risks. Body fat and its relation to other body components can be quantitated in many ways. From a practical point of view, the use of body mass or Quetelet index, defined as the ratio of weight (kg) divided by the square of the height (m2) is the most useful. Overweight is defined as a BMI of 25 to 30 kg/m2 and obesity as a BMI above 30 kg/m2. The WHR can provide additional information about the risk of obesity. Using BMI, the prevalence of overweight in the English-speaking countries of Australia, Great Britain, and the United States is almost identical at 24% of women and 31 to 34% of men. In the obese category, there are more Americans (12%) than in the other two countries (6-8%). There is a U-shaped relationship between weight and risk of death. When body weight is increased 20% above average, the extra mortality rises to 20% for men and 10% for women. This extra mortality is associated with an increased death rate from heart disease, hypertension, diabetes mellitus, digestive diseases, and cancer. In addition to an increased risk of death, overweight individuals demand more from their heart, lungs, and musculoskeletal and digestive systems.
QCD mechanisms for double quarkonium and open heavy meson hadroproduction

Abstract Double J/ψ production on the order of 20–30 pb has been observed by the NA3 collaboration. These ψψ pairs, measured in or π−N interactions at 150 and 280 GeV/c interactions at 400 GeV/c, carry a large fraction of the projectile momentum, xψψ ≥ 0.6 for the 150 GeV/c beam and ≥ 0.4 at 280 GeV/c. We examine several sources of ψψ pair production within QCD, including O(αs4) ψψ production, leading-twist b b production and decay, abd the materialization of heavy-quark Fock states in the projectile. We estimate the production cross section and the single and double J/ψ momentum and mass distributions for each, comparing the results with the NA3 data, and predict ψψ production in pN interactions at 800 GeV/c, accessible to current fixed-target experiments. We also discuss the observable implications of open heavy meson pair production from the intrinsic heavy quark Fock states.
Molecular Gas Adsorption Induced Carrier Transport Studies of Epitaxial Graphene Using IR Reflection Spectroscopy

We investigate molecular adsorption doping by electron withdrawing NO2 and electron donating NH3 on epitaxial graphene. Amperometric measurements show conductance changes upon introduction of molecular adsorbents on epitaxial graphene. Conductance changes are a trade-off between carrier concentration and scattering, and manifest at direct current and optical frequencies. We therefore investigate changes in the infrared (IR) reflection spectra to correlate these two frequency domains, as reflectance changes are due to a change of EG surface conductance. We match theory with experimental IR data and extract changes in carrier concentration and scattering due to gas adsorption. Finally, we separate the intraband and interband scattering contributions to the electronic transport under gas adsorption. The results indicate that, under gas adsorption, the influence of interband scattering cannot be neglected, even at DC.
Redundant nonholonomic mechanical systems: characterization and control

This paper introduces the notion of kinematic redundancy in nonholonomic mechanical systems, identifies some of the interesting properties which result because of the presence of the redundancy, and initiates a study of the control and application of these systems. It is shown that kinematic redundancy in nonholonomic system can be exploited both to simplify the problem of controlling these systems and to enhance their performance capabilities. Moreover, it is demonstrated that these results can be obtained even in the presence of considerable uncertainty regarding the system model. The proposed ideas are illustrated through the study of three example systems: a space robot, a mobile manipulator, and a tractor-trailer system with two steering inputs (fire truck).
Is ferrocene more aromatic than benzene

A combination of Pd-catalyzed arene–alkynyl couplings and Cu(OAc)2-promoted internal alkyne dimerization furnishes novel ferrocene-based dehydroannulenes in high yield.
Exploring In-Situ Sensing Irregularity in Wireless Sensor Networks

The circular sensing model has been widely used to estimate performance of sensing applications in existing analyses and simulations. While this model provides valuable high-level guidelines, the quantitative results obtained may not reflect the true performance of these applications, due to the sensing irregularity introduced by existence of obstacles in real deployment areas and insufficient hardware calibration. In this paper, we design and implement two sensing area modeling (SAM) techniques useful in the real world. They complement each other in the design space. Physical sensing area modeling (P-SAM) provides accurate physical sensing area for individual nodes using controlled or monitored events, while virtual sensing area modeling (V-SAM) provides continuous sensing similarity between nodes using natural events in an environment. With these two models, we pioneer an investigation of the impact of sensing irregularity on application performance, such as coverage scheduling. We evaluate SAM extensively in real-world settings, using testbeds consisting of 14 XSM motes. To study the performance at scale, we also provide an extensive 1,400-node simulation. Evaluation results reveal several serious issues concerning circular models and demonstrate significant improvements in several applications when SAM is used instead.
On the periodicity of symbolic observations of piecewise smooth discrete-time systems

A study is made of the behavior of discrete-time systems composed of a set of smooth transition maps coupled by a quantized feedback function. The feedback function partitions the state space into disjoint regions and assigns a smooth transition function to each region. The main result is that under a constraint on the norm of the derivative of the transition maps, a bounded state trajectory with limit points in the interior of the switching regions leads to a region index sequence that is eventually periodic. Under these assumptions, it is shown that eventually the feedback function is determined by a finite state automaton. A similar result is proved in the case of finite state dynamic feedback. >
Boundary-layer measurements on an airfoil at low Reynolds numbers

Etude experimentale des caracteristiques des bulles de decollement de transition par anemometrie laser et a fil chaud
Corporate tax evasion with agency costs

This paper examines corporate tax evasion in the context of the contractual relationship between the shareholders of a firm and a tax manager who possesses private information regarding the extent of legally permissible reductions in taxable income, and who may also undertake illegal tax evasion. Using a costly state falsification framework, we characterize formally the optimal incentive compensation contract for the tax manager and, in particular, how the form of that contract changes in response to alternative enforcement policies imposed by the taxing authority. The optimal contract may adjust to offset, at least partially, the effect of sanctions against illegal evasion, and we find a new and policy-relevant non-equivalence result: penalties imposed on the tax manager are more effective in reducing evasion than are those imposed on shareholders.
Global Capitalism Theory and the Emergence of Transnational Elites

The class and social structure of developing nations has undergone profound transformation in recent decades as each nation has incorporated into an increasingly integrated global production and financial system. National elites have experienced a new fractionation. Emergent transnationally-oriented elites grounded in globalized circuits of accumulation compete with older nationally-oriented elites grounded in more protected and often state-guided national and regional circuits. This essay focuses on structural analysis of the distinction between these two fractions of the elite and the implications for development. I suggest that nationally-oriented elites are often dependent on the social reproduction of at least a portion of the popular and working classes for the reproduction of their own status, and therefore on local development processes however so defined whereas transnationally-oriented elites are less dependent on such local social reproduction. The shift in dominant power relations from nationally- to transnationally-oriented elites is reflected in a concomitant shift to a discourse from one that defines development as national industrialization and expanded consumption to one that defines it in terms of global market integration.