cssi/SciSciGPT-SciSciNet huggingface dataset:
Paramagnet induced signal quenching in MAS-DNP experiments in frozen homogeneous solutions.

Abstract The effects of nuclear signal quenching induced by the presence of a paramagnetic polarizing agent are documented for conditions used in magic angle spinning (MAS)–dynamic nuclear polarization (DNP) experiments on homogeneous solutions. In particular, we present a detailed analysis of three time constants: (1) the longitudinal build-up time constant TB for 1H; (2) the rotating frame relaxation time constant T1ρ for 1H and 13C and (3) T2 of 13C, the transverse relaxation time constant in the laboratory frame. These relaxation times were measured during microwave irradiation at a magnetic field of 5 T (140 GHz) as a function of the concentration of four polarizing agents: TOTAPOL, 4-amino-TEMPO, trityl (OX063), and Gd-DOTA and are compared to those obtained for a sample lacking paramagnetic doping. We also report the EPR relaxation time constants T1S and T2S, the DNP enhancements, e, and the parameter E, defined below, which measures the sensitivity enhancement for the four polarizing agents as a function of the electron concentration. We observe substantial intensity losses (paramagnetic quenching) with all of the polarizing agents due to broadening mechanisms and cross relaxation during MAS. In particular, the monoradical trityl and biradical TOTAPOL induce ∼40% and 50% loss of signal intensity. In contrast there is little suppression of signal intensity in static samples containing these paramagnetic species. Despite the losses due to quenching, we find that all of the polarizing agents provide substantial gains in signal intensity with DNP, and in particular that the net enhancement is optimal for biradicals that operate with the cross effect. We discuss the possibility that much of this polarization loss can be regained with the development of instrumentation and methods to perform electron decoupling.
An improved synthesis of the (E,Z)-dienoate precursor of (+)-damavaricin D via a vinylogous Horner-Wadsworth-Emmons reaction

Abstract An improved synthesis of the C(1)–C(5) (E,Z)-dienoate segment of (+)-damavaricin D precursor 3 was accomplished using the unsaturated phosphonate reagent 9 in a (Z)-selective vinylogous Horner-Wadsworth-Emmons reaction.
A New Species of Hybochaetodus Arrow (Coleoptera: Scarabaeoidea: Hybosoridae: Anaidini) from Peru

Abstract Hybochaetodus flaco Ocampo, new species, from Cusco, Peru is described and illustrated. The genus Hybochaetodus now includes two species, H. flaco and H. obscurus Arrow, both from Peru. The two species are compared and a diagnosis for the genus Hybochaetodus Arrow is provided.
Vlasov multi-dimensional model dispersion relation

A hybrid model of the Vlasov equation in multiple spatial dimension D > 1 [H. A. Rose and W. Daughton, Phys. Plasmas 18, 122109 (2011)], the Vlasov multi dimensional model (VMD), consists of standard Vlasov dynamics along a preferred direction, the z direction, and N flows. At each z, these flows are in the plane perpendicular to the z axis. They satisfy Eulerian-type hydrodynamics with coupling by self-consistent electric and magnetic fields. Every solution of the VMD is an exact solution of the original Vlasov equation. We show approximate convergence of the VMD Langmuir wave dispersion relation in thermal plasma to that of Vlasov-Landau as N increases. Departure from strict rotational invariance about the z axis for small perpendicular wavenumber Langmuir fluctuations in 3D goes to zero like θN, where θ is the polar angle and flows are arranged uniformly over the azimuthal angle.
Have Anti-Discrimination Housing Laws Worked? Evidence from Trends in Black Homeownership

This paper explores the hypothesis that anti-discrimination legislation has been an important factor in shaping the evolution of minority homeownership spatial trends. It does so by studying homeownership patterns of black and non-black households during the 1970s, 1980s, and 1990s using Census data and data that proxies for the level of enforcement of the Fair Housing Act over time. The results provide unambiguous support for the view that enforcement has been a key factor for black homeownership since the 1970s, as we find a consistent positive relationship between fair housing policy enforcement and black homeownership growth. In addition, we find clear evidence that black homeowners gained access to more diverse and higher-income neighborhoods over time, with the shift occurring beginning in the 1980s and continuing in the 1990s. Importantly, both of these results are race-specific results, as there are no such patterns among non-black homeowners. Taken together, the results are consistent with the view that the housing-related civil rights legislation passed during the 1960s and 1970s helped alter, and reduce, the role that race played in housing markets.
Chemosensitivity testing with ChemoFx and overall survival in primary ovarian cancer

Objective We sought to determine the association between tumor responses in vitro to platinum therapy by using the ChemoFx drug response marker and overall survival (OS) after first-line platinum-based chemotherapy in patients with advanced-stage primary ovarian cancer (POC). Study Design Chemosensitivity testing was performed in vitro on tumors from 192 POC patients. Tumors were classified as responsive, intermediately responsive, and nonresponsive to chemotherapy. Physicians made all management decisions. Survival status was retrieved from the Social Security Death Index. OS was modeled using Cox proportional hazard regression analysis. Results Median OS was 72.5 months for patients with tumors categorized as responsive, 48.6 months for intermediately responsive, and 28.2 months for nonresponsive ( P = .03; hazard ratio, 0.70; 95% confidence interval, 0.50–0.97). The ChemoFx prediction of responses to platinum agents was an independent predictor of OS. Conclusion Results of chemosensitivity testing with a drug response marker for therapy was predictive of OS in POC patients.
Effects of heavy states on the effective N = 1 supersymmetric action

Abstract Using the power of superspace formalism, we investigate the decoupling effects of heavy states in N = 1 supersymmetric field theory. We find that “mixed” couplings in the superpotential between the heavy and light fields contribute to the effective superpotential at the leading order, and also contribute to the effective Kahler potential (in the next to leading order). Mixed couplings in the Kahler potential always contribute to the effective Kahler potential at the leading order. Several examples are presented which illustrate the effects explicitly.
Reconciling psychology with economics: Obesity, behavioral biology, and rational overeating

The modern phenomenon of obesity is an archetypal example of a behavior whose explanation simultaneously falls within the purview of psychology, economics, and the biological sciences. While psychologists and advocates of public health have long viewed overeating as a weakness or disease in need of treatment, economists have pointed out that—like any other consumer behavior—choices about diet and exercise can be viewed from the perspective of rational decision theory, subject to the influence of variation in prices and income but not necessarily as a problem in need of a solution. Recent advances in our understanding of the physiological mechanisms by which genes influence behavior in modern socioeconomic environments have begun to point the way to a resolution to this debate. Drawing inspiration from the scientific literature on the neuroendocrinology of energy homeostasis, this paper reviews the empirical determinants of obesity in light of the biologist’s notion that humans and other animals evolved the ability to store body fat as an optimal response to the presence of starvation risk. This approach yields a powerful theoretical foundation, capturing such features of obesity as dynamic inconsistency, genetic variation, susceptibility to pharmaceutical intervention, and variation by season, socioeconomic status, and degree of financial security. It also provides a framework for reconciling the conflict between behavioral and neoclassical economics.
The Andersen-Jordan equation revisited

Abstract This paper deals with two common econometric criticisms of the Andersen and Jordan (1968) equation—the endogeneity of the right-hand-side variables and the ad hoc implementation of Almon's polynomial distributed lag estimation technique. Using the original Andersen-Jordan data, we found no support for either criticism. While we note that the PDL specification of their equation is highly unusual, we found that their policy conclusions do not depend their particular choice of lag length or polynomial degree or their imposition of the endpoint constraints. Furthermore, the right-hand-side variables were found to satisfy necessary conditions for statistical exogeneity.
NMR solution structure and condition-dependent oligomerization of the antimicrobial Peptide human defensin 5.

Human defensin 5 (HD5) is a 32-residue host-defense peptide expressed in the gastrointestinal, reproductive, and urinary tracts that has antimicrobial activity. It exhibits six cysteine residues that are regiospecifically oxidized to form three disulfide bonds (Cys(3)-Cys(31), Cys(5)-Cys(20), and Cys(10)-Cys(30)) in the oxidized form (HD5(ox)). To probe the solution structure and oligomerization properties of HD5(ox), and select mutant peptides lacking one or more disulfide bonds, NMR solution studies and analytical ultracentrifugation experiments are reported in addition to in vitro peptide stability assays. The NMR solution structure of HD5(ox), solved at pH 4.0 in 90:10 H(2)O/D(2)O, is presented (PDB: 2LXZ ). Relaxation T(1)/T(2) measurements and the rotational correlation time (τ(c)) estimated from a (15)N-TRACT experiment demonstrate that HD5(ox) is dimeric under these experimental conditions. Exchange broadening of the Hα signals in the NMR spectra suggests that residues 19-21 (Val(19)-Cys(20)-Glu(21)) contribute to the dimer interface in solution. Exchange broadening is also observed for residues 7-14 comprising the loop. Sedimentation velocity and equilibrium studies conducted in buffered aqueous solution reveal that the oligomerization state of HD5(ox) is pH-dependent. Sedimentation coefficients of ca. 1.8 S and a molecular weight of 14 363 Da were determined for HD5(ox) at pH 7.0, supporting a tetrameric form ([HD5(ox)] ≥ 30 μM). At pH 2.0, a sedimentation coefficient of ca. 1.0 S and a molecular weight of 7079 Da, corresponding to a HD5(ox) dimer, were obtained. Millimolar concentrations of NaCl, CaCl(2), and MgCl(2) have a negligible effect on the HD5(ox) sedimentation coefficients in buffered aqueous solution at neutral pH. Removal of a single disulfide bond results in a loss of peptide fold and quaternary structure. These biophysical investigations highlight the dynamic and environmentally sensitive behavior of HD5(ox) in solution, and provide important insights into HD5(ox) structure/activity relationships and the requirements for antimicrobial action.
A Determination of the Local Acceleration of Gravity for the NIST-4 Watt Balance

A new watt balance is being constructed at the National Institute of Standards and Technology in preparation for the redefinition of the International System of Units and the realization of mass through an exact value of the Planck constant. The total relative uncertainty goal for this instrument of a few parts in $10^{8}$ requires that the local acceleration due to gravity has to be known at the location of a test mass with a relative uncertainty on the order of only a few parts in $10^{9}$ . To make this determination, both the horizontal and vertical gradients of gravity must be known such that gravity may be tied from an absolute reference in the laboratory to the precise mass location. We describe the procedures used to model and measure gravity variations throughout the laboratory and give our results.
Picosecond Raman studies of field-induced transient hole transport in an Al0.3Ga0.7As-based p–i–n nanostructure

Abstract Electric field-induced transient hole transport in an Al0.3Ga0.7As-based p–i–n nanostructure has been studied by picosecond Raman spectroscopy at T=300 K. Our experimental results demonstrate that at T=300 K, for a 5-ps excitation laser pulse and a hole density of nh≅5×1017 cm−3, transient hole drift velocity increases from zero to ≅(3±0.7)×10 6 cm/s when the applied electric field intensity increases from E=0 to 15 kV/cm. The transient hole drift velocity then becomes saturated at ≅(8±0.8)×10 6 cm/s for the applied electric field intensity of E⩾25 kV/cm and up to 65 kV/cm.
THE S-PIXYL GROUP : AN EFFICIENT PHOTOCLEAVABLE PROTECTING GROUP FOR THE 5' HYDROXY FUNCTION OF DEOXYRIBONUCLEOSIDES

Abstract The 9-phenylthioxanthyl (S-pixyl or S-Px) group has been investigated as a photocleavable protecting group for primary alcohols, and specifically as a 5′ hydroxy protecting group for deoxyribonucleosides. Several alcohols, including the four nucleosides with protected exocyclic amino functions, were protected in very good to excellent yield by treatment of 9-chloro-9-phenylthioxanthene 3 in dry pyridine to reveal the derivatized compounds. Irradiation of the protected substrates in neutral, aqueous solution regenerated the starting alcohols in excellent yield.
Theoretical Challenges of Determining Low-Energy Neutron Capture Cross Sections via the Surrogate Technique

Cross sections for radiative neutron capture on unstable nuclei at low energies are difficult to calculate with high precision, and can be impossible to measure directly. It is therefore important to explore alternative methods. The prospects of one such method, the Surrogate Nuclear Reaction Technique, is currently being investigated at Lawrence Livermore National Laboratory. The purpose of this paper is to outline the strategy for combining the results from a surrogate experiment with theoretical calculations in order to extract the desired cross section.
Optically Faint Microjansky Radio Sources.

We report on the identifications of radio sources from our survey of the Hubble Deep Field (HDF) and the Small Selected Area 13 fields, both of which comprise the deepest radio surveys to date at 1.4 and 8.5 GHz, respectively. About 80% of the microjansky radio sources are associated with moderate-redshift starburst galaxies or active galactic nuclei within the I-magnitude range of 17-24 with a median of I = 22 mag. Thirty-one (20%) of the radio sources are (1) fainter than I > 25 mag, with two objects in the HDF IAB > 28.5, (2) often identified with very red objects I-K > 4, and (3) not significantly different in radio properties than the brighter objects. We suggest that most of these objects are associated with heavily obscured starburst galaxies with redshifts between 1 and 3. However, other mechanisms are discussed and cannot be ruled out with the present observations.
Metformin therapy throughout pregnancy reduces the development of gestational diabetes in women with polycystic ovary syndrome

Abstract Objective: To assess whether metformin safely reduced development of gestational diabetes in women with the polycystic ovary syndrome (PCOS). Design: Prospective and retrospective study. Setting: Outpatient clinical research center. Patient(s): The prospective study included 33 nondiabetic women with PCOS who conceived while taking metformin and had live births; of these, 28 were taking metformin through delivery. The retrospective study included 39 nondiabetic women with PCOS who had live birth pregnancies without metformin therapy. Intervention(s): Metformin, 2.55 g/d, throughout pregnancy in women with PCOS. Main Outcome Measure(s): Development of gestational diabetes in women with PCOS. Result(s): Before metformin therapy, after covariance adjustment for age, the two cohorts did not differ in height, weight, basal metabolic index, insulin, insulin resistance, or insulin secretion. Both cohorts had high fasting insulin, were insulin resistant, and had high insulin secretion. Among the 33 women who received metformin, gestational diabetes developed in 1 of 33 (3%) pregnancies versus 8 of 12 (67%) of their previous pregnancies without metformin. Among the 39 women who did not take metformin, gestational diabetes developed in 14 of 60 (23%) pregnancies. When all live births were combined, gestational diabetes occurred in 22 of 72 pregnancies (31%) in women who did not take metformin versus 1 of 33 pregnancies (3%) in those who took metformin. With gestational diabetes as the response variable and age at delivery and treatment group (metformin or no metformin) as explanatory variables, the odds ratio for gestational diabetes in women with metformin versus without metformin was 0.093 (95% CI: 0.011 to 0.795). With gestational diabetes in 93 pregnancies as the response variable and age at delivery and treatment group (metformin no metformin) as explanatory variables, the odds ratio of gestational diabetes in pregnancies in women taking metformin versus without metformin was 0.115 (95% CI: 0.014 to 0.938). Conclusion(s): In PCOS, use of metformin is associated with a 10-fold reduction in gestational diabetes (31% to 3%). It also reduces insulin resistance and insulin secretion, thus decreasing the secretory demands imposed on pancreatic β-cells by insulin resistance and pregnancy.
Silicon-based Molecular Electronics

Molecular electronics on silicon has distinct advantages over its metallic counterpart. We describe a theoretical formalism for transport in semiconductor−molecule heterostructures, formally combining a semiempirical treatment of bulk silicon with a first-principles description of the molecular chemistry and its bonding with silicon. Using this method, we demonstrate that the presence of a semiconducting band-edge can lead to a novel molecular resonant tunneling diode (RTD) that shows negative differential resistance (NDR) when the molecular levels are driven by an STM potential into the semiconducting band gap. The NDR peaks show a clear polarity reversal, appearing for positive bias on a p-doped and negative for an n-doped substrate, a feature that is in agreement with recent experiments by Guisinger et al.1,2
Novel method of measuring electron positron colliding beam parameters

Abstract Through the simultaneous measurement of the transverse size as a function of longitudinal position, and the longitudinal distribution of luminosity, we are able to measure β y * (the vertical envelope function at the collision point), vertical emittance, and bunch length of colliding beams at the Cornell Electron–positron Storage Ring (CESR). This measurement is possible due to the significant “hourglass” effect at CESR and the excellent tracking resolution of the CLEO detector.
Hot electrons in silicon dioxide: Ballistic to steady-state transport

Abstract Hot electron transport in silicon dioxide is examined with emphasis on current experimental and theoretical results. For oxide layers thicker than 100 A, steady-state transport has been shown to control the carrier flow at all fields studied. The transition from a nearly thermal electron distribution at electric fields less than approximately 1.5 MV/cm to significantly hot distributions with average energies between 2 and 6 eV at higher fields of up to 16 MV/cm is discussed. The significance of nonpolar phonon scattering in controlling the dispersive transport at higher electric fields, thereby preventing runaway and avalanche breakdown, is reviewed. The transition from ballistic to steady-state transport on very thin oxides layers of less than 100 A in thickness and the observation of single phonon scattering events are also discussed.
The Quality of ECN and Nasdaq Market Maker Quotes

This paper compares the quality of quotes submitted by electronic communication networks (ECNs) and by traditional market makers to the Nasdaq quote montage. An analysis of the most active Nasdaq stocks shows that ECNs not only post informative quotes, but also, compared to market makers, ECNs post quotes rapidly and are more often at the inside. Additionally, ECN quoted spreads are smaller than dealer quoted spreads. The evidence suggests that the proliferation of alternative trading venues, such as ECNs, may promote quote quality rather than fragmenting markets. Moreover, the results suggest that a more open book contributes to quote quality.
Alkene metathesis approach to β-unsubstituted anti-allylic alcohols and their use in ene-yne metathesis.

The synthesis of β-unsubstituted, anti-allylic alcohols using a catalytic Evans aldol reaction conjoined with a relay-type ring-closing alkene metathesis is reported. The metathesis step serves to remove a β-alkenyl group, which facilitated the aldol step. The β-substituted enals serve as acrolein surrogates. The products were employed in ene–yne cross metathesis.
Dynamic mechanical analysis of fiber reinforced composites

Dynamic mechanical and thermal properties were determined for unidirectional epoxy/glass composites at various fiber orientation angles. Resonant frequency and relative logarithmic decrement were measured as functions of temperature. In low angle and longitudinal specimens a transition was observed above the resin glass transition temperature which was manifested mechanically as an additional damping peak and thermally as a change in the coefficient of thermal expansion. The new transition was attributed to a heterogeneous resin matrix induced by the fiber. The temperature span of the glass-rubber relaxation was found to broaden with decreasing orientation angle, reflecting the growth of fiber contribution and exhibiting behavior similar to that of Young's modulus. The change in resonant frequency through the glass transition was greatest for samples of intermediate fiber angle, demonstrating behavior similar to that of the longitudinal shear modulus.
In Pursuit of the Elusive Supersolid

The excitement following the initial report of supersolid behavior for 4He embedded in porous Vycor glass has been tempered by the realization that many of the early supersolid observations were contaminated by effects arising from an anomaly in the elastic properties of solid 4He. In an attempt to separate dynamic elastic effects from a true supersolid signal, we employed a torsional oscillator with two eigen-frequencies to study the 4He-Vycor system. We found that frequency-dependent elastic signals can entirely account for the observed period shift signals. Although, we conclude that supersolid does not exist for the 4He-Vycor case, the question of its presence in bulk samples remains open. In our current experiments we apply the two-frequency test to bulk samples of solid 4He. Again we find a frequency-dependent contribution arising from elastic effects; however, in some cases we also find a small frequency-independent contribution, which may indicate the existence of a remnant supersolid phase. Given the history of this subject such results must be treated with caution.
HArtree‐fock lattice constant and bulk modulus of diamond

The equilibrium lattice constant of diamond is calculated in the Hartree-Fock approximation to be 3.547 ± 0.0019 A. This value is slightly smaller than the experimental value of 3.567 A, as it should be. The Hartree-Fock bulk modulus is calculated to be 4.64 ± 0.27 × 1012 dyn/cm2, compared to the experimental value of 4.42 × 1012 dyn/cm2.
Instanton method for the electron propagator

Abstract A nonperturbative theory of the electron propagator is developed and used to calculate the one-particle Green's function and tunneling density of states in strongly correlated electron systems. The method, which is based on a Hubbard–Stratonovich decoupling of the electron–electron interaction combined with a cumulant expansion of the resulting noninteracting propagator, provides a possible generalization of the instanton technique to the calculation of the electron propagator in a many-body system. Application to the one-dimensional electron gas with short-range interaction is discussed.
Turbulent viscosity and Jupiter's tidal Q

A recent estimate of tidal dissipation by turbulent viscosity in Jupiter's convective interior predicts that the current value of the planet's tidal Q ∼ 5 × 10^6. We point out a fundamental error in this calculation, and show that turbulent dissipation alone implies that at present Q ∼ 5 × 10^(13). Our reduced estimate for the rate of tidal dissipation shows conclusively that tidal torques have produced only negligible modifications of the orbits of the Galilean satellites over the age of the solar system.
Compressive radar with off-grid targets: a perturbation approach

Compressed sensing (CS) schemes are proposed for monostatic as well as synthetic aperture radar (SAR) imaging with chirped signals and ultra-narrowband (UNB) continuous waveforms. In particular, a simple, perturbation method is developed to reduce the gridding error for off-grid targets. A coherence bound is obtained for the resulting measurement matrix. A greedy pursuit algorithm, support-constrained orthogonal matching pursuit, is proposed to take advantage of the support constraint in the perturbation formulation and proved to have the capacity of determining the off-grid targets to the grid accuracy under favorable conditions. Alternatively, the locally optimized thresholding is proposed to enhance the performance of the CS method, basis pursuit. For the advantages of higher signal-to-noise ratio and signal-to-interference ratio, it is proposed that Spotlight SAR imaging will be implemented with CS techniques and multi-frequency UNB waveforms. Numerical simulations show promising results of the proposed approach and algorithms.
Quasisymmetric parametrizations of two-dimensional metric spheres

According to the classical uniformization theorem, every smooth Riemannian surface Z homeomorphic to the 2-sphere is conformally diffeomorphic to S2 (the unit sphere inR3 equipped with the Riemannian metric induced by the ambient Euclidean metric). The availability of a similar uniformization procedure for spheres with a “generalized conformal structure” is highly desirable, in particular in connection with Thurston’s hyperbolization conjecture. This was addressed by Cannon in his combinatorial Riemann mapping theorem [7]. He considers topological surfaces equipped with a sequence of “shinglings”—a combinatorial structure that leads to a notion of approximate conformal moduli of rings. He then finds conditions that imply the existence of coordinate systems on the surface that relate these combinatorial moduli to classical analytic moduli in the plane. In this paper we develop a uniformization theory for a different type of generalized conformal structure. We start with a metric space Z homeomorphic to S2 and ask for conditions under which Z can be mapped onto S2 by a quasisymmetric homeomorphism. The class of quasisymmetries is an appropriate analog of conformal1 mappings in a metric space context. Quasisymmetric homeomorphisms also arise in the theory of Gromov hyperbolic metric spaces—quasi-isometries between Gromov hyperbolic spaces induce quasisymmetric boundary homeomorphisms. Our setup has the advantage that we can exploit recent notions and methods from Analysis
The evolution of interplanetary shocks

Unambiguous identification of the solar events associated with 48 interplanetary (IP) shocks has been facilitated by the observation of radio emission generated by the shocks. This identification makes possible an investigation of the way in which these shocks evolve and of the relationship between solar event 'strength' and shock velocity. All but two of the 48 solar events associated with IP type II radio emission included long-duration soft X-ray events (LDE's). In addition, it is shown that all intense LDE's are associated with IP shocks. A weak correlation between the integral flux of soft X-rays and the average velocity of the associated shock is suggested. However, for two events all of the usual flare signatures were absent, and the events are associated with the disappearance of solar filaments. It is shown that the shocks propagate isotropically over about 50 deg from the source site. Beyond 50 deg the shocks weaken particularly on their eastern flanks. As a consequence, shocks originating on the west limb cannot reach the earth. IP type II radio emission is dependent on shock velocity with faster shocks producing more intense emission. The study shows that radio intensities provide information about the evolution of IP shocks.
Benzosilacyclohexadienones: synthesis and reactivity

Abstract The synthesis and the allylic oxidation reaction of new benzosilacyclohexenes are described. The reactivity of these new cyclic β-silyl-α,β-unsaturated ketones in cycloaddition reactions, as well as in 1,4-addition reactions, is discussed.
New concepts in spectrum usage

The author alleges that there is no shortage of radio spectrum, but rather, a shortage of new concepts in spectrum usage. The recent reallocation of additional frequencies to land mobile radio uses (FCC Dockets 18 261 and 18 262) provides new opportunities for innovative approaches, approaches that are free of the constraints of existing rules and regulations, existing manufacturing and engineering processes and concepts. Intending to be provocative and to initiate action and dialogue, the author challenges the technologists of this industry to come forward with innovative approaches based upon thorough, objective engineering analyses. The FCC, he contends, sorely needs factual, objective data from industry technologists in order to make the best decisions possible.
Deducing the multidimensional Szemerédi theorem from an infinitary removal lemma

We offer a new proof of the Furstenberg-Katznelson multiple recurrence theorem for several commuting probability-preserving transformations T1, T2, …, Td: ℤ ↷ (X, ∑, µ) ([6]), and so, via the Furstenberg correspondence principle introduced in [5], a new proof of the multi-dimensional Szemeredi Theorem. We bypass the careful manipulation of certain towers of factors of a probability-preserving system that underlies the Furstenberg-Katznelson analysis, instead modifying an approach recently developed in [1] to pass to a large extension of our original system in which this analysis greatly simplifies. The proof is then completed using an adaptation of arguments developed by Tao in [13] for his study of an infinitary analog of the hypergraph removal lemma. In a sense, this addresses the difficulty, highlighted by Tao, of establishing a direct connection between his infinitary, probabilistic approach to the hypergraph removal lemma and the infinitary, ergodic-theoretic approach to Szemeredi’s Theorem set in motion by Furstenberg [5].
Broadband focal plane wavefront control of amplitude and phase aberrations

The Stroke Minimization algorithm developed at the Princeton High Contrast Imaging Laboratory has proven symmetric dark hole generation using minimal stroke on two deformable mirrors (DM) in series. The windowed approach to Stroke Minimization has proven symmetric dark holes over small bandwidths by using three wavelengths to define the bandwidth of correction in the optimization problem. We address the relationship of amplitude and phase aberrations with wavelength, how this changes with multiple DMs, and the implications for simultaneously correcting both to achieve symmetric dark holes. Operating Stroke Minimization in the windowed configuration requires multiple wavelength estimates. To save on exposures, a single estimate is extrapolated to bounding wavelengths using the established relationship in wavelength to produce multiple estimates of the image plane electric field. Here we demonstrate better performance by improving this extrapolation of the estimate to other wavelengths. The accuracy of the functional relationship will ultimately bound the achievable bandwidth, therefore as a metric these results are also compared to estimating each wavelength separately. In addition to these algorithm improvements, we also discuss a laboratory upgrade and how it can better simulate broadband starlight. We also discuss the possibility of leveraging two DMs in series to directly estimate the electric field over a narrow bandwidth and the challenges associated with it.
Decentralized commanding and supervision: the distributed projective virtual reality approach

As part of the cooperation between the University of Souther California (USC) and the Institute of Robotics Research (IRF) of the University of Dortmund experiments regarding the control of robots over long distances by means of virtual reality based man machine interfaces have been successfully carried out. In this paper, the newly developed virtual reality system that is being used for the control of a multi-robot system for space applications as well as for the control and supervision of industrial robotics and automation applications is presented. The general aim of the development was to provide the framework for Projective Virtual Reality which allows users to project their actions in the virtual world into the real world primarily by means of robots but also by other means of automation. The framework is based on a new approach which builds on the task deduction capabilities of a newly developed virtual reality system and a task planning component. The advantage of this new approach is that robots which work at great distances from the control station can be controlled as easily and intuitively as robots that work right next to the control station. Robot control technology now provides the user in the virtual world with a prolonged arm into the physical environment, thus paving the way for a new quality of user-friendly man machine interfaces for automation applications. Lately, this work has been enhanced by a new structure that allows to distribute the virtual reality application over multiple computers. With this new step, it is now possible for multiple users to work together in the same virtual room, although they may physically be thousands of miles apart. They only need an Internet or ISDN connection to share this new experience. Last but not least, the distribution technology has been further developed to not just allow users to cooperate but to be able to run the virtual world on many synchronized PCs so that a panorama projection or even a cave can be run with 10 synchronized PCs instead of high-end workstations, thus cutting down the costs for such a visualization environment drastically and allowing for a new range of applications.
A Scaled Model Study of Water Coning

An experimental study has been carried out on a 3 dimensional scaled model which employed porous media and analog fluids to stimulate oil reservoirs produced by natural water drive or waterflooding. The reservoirs modeled were either horizontally stratified or had relatively thin oil column heights. The model tests were performed under varying conditions of production rate, mobility ratio, and relative permeability to water in the water-invaded region of the oil zone. The ratio of oil to water-sand thickness was also varied. A record was made of water-oil contact positions at different times during the model runs. This record consisted of sets of tracings of the water cone positions at different times during production. The fluid production from the model and the water-cut value for each tracing was also noted. The data indicate that the degree of water coning and the value of the water cut increase with: (1) production rate, (2) mobility ratio across the moving boundary, (3) mobility ratio across the fixed boundary, and (4) ratio of aquifer to oil-sand thickness. A technique is provided for applying the laboratory data to field situations.
Some interesting properties of metals confined in time and nanometer space of different shapes.

The properties of a material depend on the type of motion its electrons can execute, which depends on the space available for them (i.e., on the degree of their spatial confinement). Thus, the properties of each material are characterized by a specific length scale, usually on the nanometer dimension. If the physical size of the material is reduced below this length scale, its properties change and become sensitive to its size and shape. In this Account we describe some of the observed new chemical, optical, and thermal properties of metallic nanocrystals when their size is confined to the nanometer length scale and their dynamical processes are observed on the femto- to picosecond time scale.
CONSTRUCTIONS OF SUBSYSTEM CODES OVER FINITE FIELDS

Subsystem codes protect quantum information by encoding it in a tensor factor of a subspace of the physical state space. They generalize all major quantum error protection schemes, and therefore are especially versatile. This paper introduces numerous constructions of subsystem codes. It is shown how one can derive subsystem codes from classical cyclic codes. Methods to trade the dimensions of subsystem and co-subsystem are introduced that maintain or improve the minimum distance. As a consequence, many optimal subsystem codes are obtained. Furthermore, it is shown how given subsystem codes can be extended, shortened, or combined to yield new subsystem codes. These subsystem code constructions are used to derive tables of upper and lower bounds on the subsystem code parameters.
Opportunities and challenges for MEMS technology in Army missile systems applications

The military market drives the thrust for the development of robust, high performance MicroElectroMechanical Systems (MEMS) devices with applications such as: competent and smart munitions, aircraft and missile autopilots, tactical missile guidance, fire control systems, platform stabilization, smart structures with embedded inertial sensors, missile system health monitoring, aerodynamic flow control, and multiple intelligent small projectiles. Army missile applications will be a fertile market for MEMS products, such as MEMS-based inertial sensors. MEMS technology should significantly enhance performance and provide more robust mission capability in applications where arrays of MEMS devices are required. The Army Aviation and Missile Command Missile Research, Development, and Engineering Center is working diligently with other government agencies, academia, and industry to develop high performing MEMS devices to withstand shock, vibration, temperature, humidity, and long-term storage conditions often encountered by Army missile systems. The goals of the ongoing DARPA MEMS technology programs will meet a significant portion of the Army missile systems requirements. In lieu of presenting an all-inclusive review of Army MEMS applications, this paper addresses a number of opportunities and associated challenges for MEMS systems operating in military environments. Near term applications and the less mature, high-risk applications of MEMS devices are addressed.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
On even-cycle-free subgraphs of the hypercube

It is shown that the size of any C"4"k"+"2-free subgraph of the hypercube Q"n, k>=3, is o(e(Q"n)).
Transmission probabilities and the quantum Hall effect

Abstract A scattering approach to magneto-transport permits the discussion of open conductors with current and voltage terminals. This approach leads to generalized longitudinal and generalized Hall resistances which are determined by the current carrying states at the Fermi energy. In samples small compared to the distance over which current carrying states equilibrate, the contact properties are crucial in determining whether the Hall voltage is quantized or not. Simple situations in which both the longitudinal and the Hall resistance are simultaneously quantized at values unrelated to the bulk properties of the sample are emphasized. The departure from the quantum Hall plateaus in narrow conductors is discussed in terms of intrinsic Breit-Wigner resonances.
HYDRA A AT LOW RADIO FREQUENCIES

We present new, low-frequency images of the powerful FR I radio galaxy Hydra A (3C 218). Images were made with the Very Large Array at frequencies of 1415, 330, and 74 MHz, with resolutions on the order of 20''. The morphology of the source is seen to be more complex and even larger than previously known and extends nearly 8' (530 kpc) in a north-south direction. The southern lobe is bent to the east and extends in that direction for nearly 3' (200 kpc). In addition, we find that the northern lobe has a flatter spectral slope than the southern lobe, consistent with the appearance of greater confinement to the south. We measure overall spectral indices α = -0.83 and α = -0.89.
Cocaine Esterase–Cocaine Binding Process and the Free Energy Profiles by Molecular Dynamics and Potential of Mean Force Simulations

The combined molecular dynamics (MD) and potential of mean force (PMF) simulations have been performed to determine the free energy profiles for the binding process of (−)-cocaine interacting with wild-type cocaine esterase (CocE) and its mutants (T172R/G173Q and L119A/L169K/G173Q). According to the MD simulations, the general protein–(−)-cocaine binding mode is not affected by the mutations; e.g.. the benzoyl group of (−)-cocaine is always bound in a subsite composed of aromatic residues W151, W166, F261, and F408 and hydrophobic residue L407, while the carbonyl oxygen on the benzoyl group of (−)-cocaine is hydrogen-bonded with the oxyanion-hole residues Y44 and Y118. According to the PMF-calculated free energy profiles for the binding process, the binding free energies for (−)-cocaine with the wild-type, T172R/G173Q, and L119A/L169K/G173Q CocEs are predicted to be −6.4, −6.2, and −5.0 kcal/mol, respectively. The computational predictions are supported by experimental kinetic data, as the calculated bind...
When did the War Begin

The Circuit Court of Appeals, Tenth Circuit, recently had occasion to decide a life insurance case, New York Life Insurance Co. v. Bennion,' the determination of which involved the interesting question, "When did the war begin for the United States ?" Mrs. Louise Bennion sued the New York Life Insurance Company for the double indemnity of $10,000 due her in the event of the death of her husband by "accident." Her husband, Captain Bennion, was killed when his ship was sunk at Pearl Harbor in the Japanese attack December 7, 1941. The company duly paid the principal sum due under the policy, $10,000. However, the policy excepted from the liability for double indemnity an accident which occurred in "war or an act incident thereto," so that if Pearl Harbor involved "war," double indemnity was not due. The issue turned on the question whether this country was at war when Pearl Harbor was attacked, or only got into war when Congress declared war, December 8, 1941, 4:10 p.m., i.e., whether the Pearl Harbdr attack occurred in time of peace, as Mrs. Bennion, the plaintiff, contended, or whether the attack was itself an act of war. The company had no difficulty in proving that every one regarded the attack as an act of war, and in holding for the insurance company, the court stated that it is commonly known that Pearl Harbor "commenced" the war.2 Reaching this result would have presented no difficulty but for the fact that in every other state and federal case which had involved deaths occurring at Pearl Harbor, the court had found against the insurance company. These cases were four in number: Savage v. Sun Life Assurance Co.,3 Pang v. Sun Life Assurance Co.,4 Rosenau v. Idaho Mutual Benefit Association,5 and West v. Palmetto State Life Insurance Co.6 These opinions are to be explained perhaps as motivated by the war hysteria, partly on the ground that they were based upon the stipulation that the declaration of war by Congress, December 8, 1941, at 4:10 p.m. was the first act of war of the political department,7 and partly as the result of the prejudice against insurance companies prevailing in certain courts. Whatever the explanation may be, these courts decided
Vision and vision loss

To provide supportive and effective care to people who must adapt to blindness or visual impairment, nurses and other health care professionals have a responsibility to be knowledgeable about the unique effect of ophthalmic disorders on the body, spirit, and mind. It is also evident that nurses must clearly understand their own emotions and social reactions to blindness and visual loss so that they can more clearly assist their clients through adaptation.
On the use of Laplace transform inversion for reconstruction of relaxation spectra

Abstract We discuss the use of Fourier transforms to construct approximate inversion formulae for the Laplace transform and apply this technique to recover the relaxation spectrum from “data” for the relaxation modulus. We show that regularization by a Gaussian, as proposed by Davies and Anderssen [A.R. Davies, R.S. Anderssen, Sampling localization in determining the relaxation spectrum, J. Non-Newt. Fluid Mech. 73 (1997) 163–179] yields reasonable results even for data with significant noise. We also show that, in principle, other choices of regularization allow the relaxation spectrum to be reconstructed from data which are taken in any interval of time or frequency, however short and wherever located. We construct formulae which would do this, based on polynomial approximation of a function in an exponentially weighted space. This algorithm, however, turns out not to be practical, and we elucidate the reasons for that.
Price effects of independent transmission system operators in the United States electricity market

In 1996, the Federal Energy Regulatory Commission (FERC) sought to “remove impediments to competition in the wholesale bulk power marketplace and to bring more efficient, lower cost power to the Nation’s electricity consumers” through a series of market rules. A product of these rules was the establishment of regional transmission organizations (RTOs) and independent system operators (ISOs) charged with facilitating equal access to the transmission grid for electricity suppliers. Whether these changes in market structure have succeeded in achieving FERC’s goal to provide “lower cost power to the Nation’s electricity consumers” remains an open question. This paper utilizes a panel data set of the 48 contiguous United States and a treatment effects model in first differences to determine whether there have been changes in delivered electric prices as a result of the establishment of ISOs and RTOs. To avoid the confounding effects of electric restructuring, the model is estimated with the full panel data set, and then again without the states that have restructured their electric markets. This estimation shows that electricity prices fall approximately 4.8 % in the first 2 years of an ISO’s operation and that this result is statistically significant. However, this result is dependent on the presence of states that restructured their electricity markets. When these restructured states are removed from the data set the price effects of RTOs become indistinguishable from zero. The paper concludes that rate agreements are the principal source of the observed decrease in prices and that RTOs have not had the desired effect on electricity prices.
A high speed parallel synthesis of 1,2-diaryl-1-ethanones via a clean-chemistry C–C bond formation reaction

Abstract In this report, we describe the parallel as well as conventional synthesis of 1,2-diaryl-1-ethanones via environmentally benign acylation of arenes with in situ generated arylacetyl trifluoroacetates. A wide variety of arylacetic acids I participated in trifluoroacetic anhydride/ phosphoric acid mediated C–C bond formation reaction when reacted with arenes of type II to give 1,2-diaryl-1-ethanones III in good to excellent yield. Under the solvent-free conditions these chemical transformations that normally require longer reaction time can be performed within minutes in good yield.
Generating anisotropic collapse and expansion solutions of Einstein’s equations

Analytic gravitational collapse and expansion solutions with anisotropic pressure are generated. Metric functions are found by requiring zero heat flow scalar. It emerges that a single function generates the anisotropic solutions. Each generating function contains an arbitrary function of time which can be chosen to fit various astrophysical time profiles. Two examples are provided: a bounded collapse metric and an expanding cosmological solution.