cssi/SciSciGPT-SciSciNet huggingface dataset:
Synthesis and physicochemical properties of zeolites containing framework titanium

Abstract Titanium-containing pure-silica ZSM-5 (TS-1), pure-silica ZSM-48 (Ti-ZSM-48) and zeolite beta (Ti-Al-beta) are synthesized and characterized by X-ray powder diffraction (XRD), elemental analysis, physical adsorption of nitrogen, Fourier transform infrared (FTIR), FT-Raman, and ultraviolet—visible (UV—VIS) spectroscopies. TS-1 is synthesized by five different methods. All materials are evaluated for their ability to oxidize 1-hexene and n -octane using aqueous hydrogen peroxide as the oxidant. The relationships between the physicochemical and catalytic properties of these titanium-containing zeolites are discussed. TS-1 samples synthesized at high pH are catalytically active and framework titanium is shown to be necessary for olefin epoxidation and alkane hydroxylation to occur. The existence of anatase in active TS-1 samples results in decreased hydrogen peroxide efficiencies in the epoxidation reaction. TS-1 produced at pH 7.4 and Ti-ZSM-48 each contain anatase and are not active. Ti-beta is found to contain framework titanium and be free of anatase. However, at the conditions used in this study these samples are not able to activate 1-hexene or n -octane.
Minimum Pay Scale and Career Length in the NBA

We use data from the National Basketball Association (NBA) to analyze the impact of minimum salaries on an employee's career length. The NBA has a salary structure in which the minimum salary a player can receive increases with the player's years of experience. The NFL has a similar minimum wage policy; research suggests that the introduction of this system shortened career length in the NFL. Using duration analysis, we fail to find evidence that the new multi-tiered minimum wage scale in the NBA increased the probability of exit.
Localization and homological stability of configuration spaces

In [Chu12], Church used representation stability to prove that the space of configurations of distinct unordered points in a closed manifold exhibit rational homological stability. A second proof was also given by Randal-Williams in [RW11] using transfer maps. We give a third proof of this fact using localization and rational homotopy theory. This gives new insight into the role that the rationals play in homological stability. Our methods also yield new information about stability for torsion in the homology of configuration spaces of points in a closed manifold.
Selection rules for optical transitions in PbSe nanocrystal quantum dots: Drastic effect of structure inversion asymmetry

We resolve a paradox according to which optical transitions seemingly forbidden in PbSe nanocrystal quantum dots by the parity selection rule exhibit large oscillator strengths in optical absorption. The transitions become allowed if the center of a spherical nanocrystal is shifted away from an atomic site leading to the structure inversion asymmetry. This asymmetry is accounted for within a four-band envelope-function formalism. Transition strengths for various optical transitions are calculated.
Combustion Oscillation Monitoring Using Flame Ionization in a Turbulent Premixed Combustor

To achieve very low NOx emission levels, lean-premixed gas turbine combustors have been commercially implemented that operate near the fuel-lean flame extinction limit. Near the lean limit, however, flashback, lean blow off, and combustion dynamics have appeared as problems during operation. To help address these operational problems, a combustion control and diagnostics sensor (CCADS) for gas turbine combustors is being developed. CCADS uses the electrical properties of the flame to detect key events and monitor critical operating parameters within the combustor. Previous development efforts have shown the capability of CCADS to monitor flashback and equivalence ratio. Recent work has focused on detecting and measuring combustion instabilities. A highly instrumented atmospheric combustor has been used to measure the pressure oscillations in the combustor, the OH emission, and the flame ion field at the premix injector outlet and along the walls of the combustor. This instrumentation allows examination of the downstream extent of the combustion field using both the OH emission and the corresponding electron and ion distribution near the walls of the combustor. In most cases, the strongest pressure oscillation dominates the frequency behavior of the OH emission and the flame ion signals. Using this highly instrumented combustor, tests were runmore » over a matrix of equivalence ratios from 0.6 to 0.8, with an inlet reference velocity of 25 m/s 82 ft/ s . The acoustics of the fuel system for the combustor were tuned using an active-passive technique with an adjustable quarter-wave resonator. Although several statistics were investigated for correlation with the dynamic pressure in the combustor, the best correlation was found with the standard deviation of the guard current. The data show a monotonic relationship between the standard deviation of the guard current (the current through the flame at the premix injector outlet) and the standard deviation of the chamber pressure. Therefore, the relationship between the standard deviation of the guard current and the standard deviation of the pressure is the most promising for monitoring the dynamic pressure of the combustor using the flame ionization signal. This addition to the capabilities of CCADS would allow for dynamic pressure monitoring on commercial gas turbines without a pressure transducer.« less
Generalized software for translating data

Many data processing installations are confronted with the problem of data conversion. Some of the conversion problems are conversion of files foreign to the installation, conversion of files into a data base management system format, and conversion of all data to upgrade hardware or software. Simple file organizations pose few conversion problems, while logically and physically complex data bases emphasize many conversion problems. The current approach of writing specific translation programs is time consuming and frequently inaccurate; a new approach is desirable.To address these conversion problems, The University of Michigan Data Translation Project has developed a generalized translation methodology. This methodology has been applied in the development of several prototype data translators. These translators have progressively advanced the physical transformation capabilities (reformatting) and the logical transformation capabilities (restructuring). The reformatting capabilities of the translators include the ability to access and modify the physical storage structures which support sequential, indexed sequential, and network organizations. The restructuring capabilities allow complex restructuring of lists, trees, and networks.Future extensions to the translation methodology include the decomposition of the translation process into small, but specific steps. Languages would be developed to address each of these small translations, and could lead to a generalized accessing mechanism and a data interchange form.
Fundamental symmetry tests with antihydrogen

Abstract The prospects for testing CPT invariance and the weak equivalence principle (WEP) for antimatter with spectroscopic measurements on antihydrogen are discussed. The potential precisions of these tests are compared with those from other measurements. The arguments involving energy conservation, the behaviour of neutral kaons in a gravitational field and the equivalence principle for antiparticles are reviewed in detail.
Structure of the Loday–Ronco Hopf algebra of trees

Abstract Loday and Ronco defined an interesting Hopf algebra structure on the linear span of the set of planar binary trees. They showed that the inclusion of the Hopf algebra of non-commutative symmetric functions in the Malvenuto–Reutenauer Hopf algebra of permutations factors through their Hopf algebra of trees, and these maps correspond to natural maps from the weak order on the symmetric group to the Tamari order on planar binary trees to the boolean algebra. We further study the structure of this Hopf algebra of trees using a new basis for it. We describe the product, coproduct, and antipode in terms of this basis and use these results to elucidate its Hopf-algebraic structure. In the dual basis for the graded dual Hopf algebra, our formula for the coproduct gives an explicit isomorphism with a free associative algebra. We also obtain a transparent proof of its isomorphism with the non-commutative Connes–Kreimer Hopf algebra of Foissy, and show that this algebra is related to non-commutative symmetric functions as the (commutative) Connes–Kreimer Hopf algebra is related to symmetric functions.
Electrical detection of ferromagnetic resonance in ferromagnet/n-GaAs heterostructures by tunneling anisotropic magnetoresistance

We observe a dc voltage peak at ferromagnetic resonance (FMR) in samples consisting of a single ferromagnetic (FM) layer grown epitaxially on the n-GaAs (001) surface. The FMR peak is detected as an interfacial voltage with a symmetric line shape and is present in samples based on various FM/n-GaAs heterostructures, including Co2MnSi/n-GaAs, Co2FeSi/n-GaAs, and Fe/n-GaAs. We show that the interface bias voltage dependence of the FMR signal is identical to that of the tunneling anisotropic magnetoresistance (TAMR) over most of the bias range. Furthermore, we show how the precessing magnetization yields a dc FMR signal through the TAMR effect and how the TAMR phenomenon can be used to predict the angular dependence of the FMR signal. This TAMR-induced FMR peak can be observed under conditions where no spin accumulation is present and no spin-polarized current flows in the semiconductor.
Geometric Integration of Quaternions

This paper employs a geometric integration algorithm to propagate the quaternion kinematics in order to preserve the unit norm. While many studies have focused on this aspect specifically while considering other systems, this work has the additional objective of studying result accuracy. Many applications including space object tracking and asteroid cataloguing require state propagation over longer time intervals where only sparse observation data is available. It is during these intervals that the quaternion norm drifts and accuracy decreases as a result of error accumulation. Quaternion trajectories obtained using third and fourth order Crouch-Grossman Lie group methods are compared with those calculated using the classical third and fourth order Runge-Kutta algorithms using different time steps. Results show that the use of the Crouch-Grossman Lie group method better preserves the quaternion unit norm for the larger time steps considered. It is also found that the fourth order Crouch-Grossman algorithm is more accurate than its Runge-Kutta counterpart except for the smallest time step used.
Nitric oxide extends the oocyte temporal window for optimal fertilization

Deteriorating oocyte quality is a critical hurdle in the management of infertility, especially one associated with advancing age. In this study, we explore the role of nitric oxide (NO) on the sustenance of oocyte quality postovulation. Sibling oocytes from superovulated mice were subjected to intracytoplasmic sperm injection (ICSI) with cauda-epididymal spermatozoa following exposure to either the NO donor, S-nitroso-N-acetylpenicillamine (SNAP, 0.23 microM/min), an NO synthase (NOS) inhibitor, N omega-nitro-L-arginine methyl ester (L-NAME, 1 mM), or an inhibitor of soluble guanylyl cyclase (sGC), 1H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one (ODQ, 100 microM); while their sibling oocytes were subjected to ICSI either before (young) or after culture for the corresponding period of time (old). Outcomes of normal fertilization, cleavage, and development to the morula and blastocyst stages were compared. Embryos from each subgroup were also subjected to TUNEL assay for apoptosis. A significant deterioration in the ability of the oocytes to undergo normal fertilization and development to morula and blastocyst stages occurred among oocytes aged in culture medium compared to their sibling cohorts subjected to ICSI immediately after ovulation (P<0.05). This deterioration was prevented in oocytes exposed to SNAP. In contrast, exposure to L-NAME or ODQ resulted in a significant compromise in fertilization and development to the morula and blastocyst stages (P<0.05). Finally, apoptosis was noted in embryos derived from aged oocytes and those exposed to L-NAME or ODQ, but not in embryos derived from young oocytes or oocytes exposed to SNAP. Thus, NO is essential for sustenance of oocyte quality postovulation.
Truth Skepticism: An Inquiry into the Value of Truth in Times of Transition

Abstract 1 Truth commissions have become so fashionable in times of transition that one can readily recognize what might be called a ‘truth cascade.’ The commissions, and the reports they produce, are reputed to promote many of the goals at the heart of the transitional justice project: helping victims to heal, promoting accountability, drawing a bright line between the past and the present, promoting reconciliation and so forth. And yet, a closer look at the truth-seeking enterprise suggests that it may not be able to deliver on these promises. This article explores both the intrinsic and instrumental reasons why truth commissions may not be effective in promoting the goals attributed to them. The article does not argue that transitional governments should not pursue the truth, but it does urge governments to use caution and careful planning when they do so.
Ceramic microstructure and adhesion

When a ceramic is brought into contact with a ceramic, a polymer, or a metal, strong bond forces can develop between the materials. The bonding forces will depend upon the state of the surfaces, cleanliness and the fundamental properties of the two solids, both surface and bulk. Adhesion between a ceramic and another solid are discussed from a theoretical consideration of the nature of the surfaces and experimentally by relating bond forces to interface resulting from solid state contact. Surface properties of ceramics correlated with adhesion include, orientation, reconstruction and diffusion as well as the chemistry of the surface specie. Where a ceramic is in contact with a metal their interactive chemistry and bond strength is considered. Bulk properties examined include elastic and plastic behavior in the surficial regions, cohesive binding energies, crystal structures and crystallographic orientation. Materials examined with respect to interfacial adhesive interactions include silicon carbide, nickel zinc ferrite, manganese zinc ferrite, and aluminum oxide. The surfaces of the contacting solids are studied both in the atomic or molecularly clean state and in the presence of selected surface contaminants.
American Kingship? Monarchical Origins of Modern Presidentialism

The modern obsession with executive charisma, especially in the context of the presidentialist variety of liberal democracy, is commonplace. This obsession derives from the oftentimes overlooked monarchical origins of the modern presidential executive. The presidential executive is outfitted with some of the awesome powers of European kingship, but it is no longer able to justify those powers on the basis of traditional religious ideas. Charisma serves as a functional replacement for religiously inspired ideas of divine monarchy. Special attention is paid to the role of Alexander Hamilton in the transformation of traditional monarchist political theory into the theoretical underpinnings of the American presidency.
A steady-state capturing method for hyperbolic systems with geometrical source terms

We propose a simple numerical method for capturing the steady state solution of hyperbolic systems with geometrical source terms. We use the interface value, rather than the cell-averages, for the source terms that balance the nonlinear convection at the cell interface, allowing the numerical capturing of the steady state with a formal high order accuracy. This method applies to Godunov or Roe type upwind methods but requires no modification of the Riemann solver. Numerical experiments on scalar conservation laws and the one dimensional shallow water equations show much better resolution of the steady state than the conventional method, with almost no new numerical complexity.
A useful methoxyvinyl cation equivalent: α-t-butyldimethylsilyl-α-methoxyacetaldehyde

Described are the synthesis and application of α-t-butyldimethylsilyl-α-methoxyacetaldehyde as a formal methoxyvinyl cation equivalent. Addition of Grignard reagents to the title aldehyde, followed by treatment of the intermediate β-hydroxysilanes with KH, gives good yields of large Z-methoxyvinylated products. Assuming a Peterson-like elimination mechanism, one can infer that the Grignard addition proceeds with high syn selectivity. These results are consistent with a chelation control model involving coordination to the α-methoxy group in the title aldehyde rather than an alternative stereoelectronic Felkin-Anh-type model. It must be noted that a steric Felkin-Anh model also accounts for the observed stereochemistry. All told, the title reagent can be employed to efficiently append a Z-configured methoxyvinyl group to an appropriate R-M species, in two steps.
Novel synthetic oleanane triterpenoids: A series of highly active inhibitors of nitric oxide production in mouse macrophages

Novel oleanane triterpenoids with modified rings A and C were designed and synthesized. Among them, methyl 2-carboxy-3,12-dioxooleana-1,9-dien-28-oate showed similar high inhibitory activity (IC50 = 0.8 nM) to 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO), which we have synthesized previously, against production of nitric oxide induced by interferon-gamma in mouse macrophages.
Horizontal Curve Accident Modification Factor with Consideration of Driveway Density on Rural Four-Lane Highways in Texas

Agencies are seeking a better understanding of those roadway or roadside features that affect safety. The objectives of this study were to develop a horizontal curve accident modification factor (AMF) for rural four-lane divided and undivided highways and to determine if the effect of driveway density is different for horizontal curves as compared to tangent sections. Data available for use in the evaluation included 194.8 centerline km (121 centerline mi) of rural four-lane highways. Negative binomial regression models were used to determine the effects of independent variables on crashes. Variables considered in developing the base models included driveway density, lane width, outside shoulder width, median width (which included inside shoulder width), median type, degree of curve, segment length, and average daily traffic. Five years (1997–2001) of driveway and segment crashes were examined. An AMF for horizontal curves was identified. Reviewing the findings with respect to driveway density revealed that the effect of driveway density is different for horizontal curves and tangents; however, the differences were relatively minor.
Evidence for Cosmic Ray Acceleration in Cassiopeia A

Combining archival data taken at radio and infrared wavelengths with state-of-the-art measurements at X-ray and gamma-ray energies, we assembled a broadband spectral energy distribution (SED) of Cas A, a young supernova remnant. Except for strong thermal emission at infrared and X-ray wavelengths, the SED is dominated by non-thermal radiation. We attempted to model the non-thermal SED with a two-zone leptonic model which assumes that the radio emission is produced by electrons that are uniformly distributed throughout the remnant while the non-thermal X-ray emission is produced by electrons that are localized in regions near the forward shock. Synchrotron emission from the electrons can account for data from radio to X-ray wavelengths. Much of the GeV-TeV emission can also be explained by a combination of bremsstrahlung emission and inverse Compton scattering of infrared photons. However, the model cannot fit a distinct feature at GeV energies. This feature can be well accounted for by adding a π0 emission component to the model, providing evidence for cosmic ray production in Cas A. We discuss the implications of these results.
Limit Games and Limit Equilibria

Abstract We provide a necessary and sufficient condition for equilibria of a game to arise as limits of ϵ-equilibria of games with smaller strategy spaces. As the smaller games are frequently more tractable, our result facilitates the characterization of the set of equilibria.
Regulation of Duopoly: Managed Competition vs Regulated Monopolies

This paper discusses the regulation of oligopolistic differentiated-product industries. The regulator can control prices and impose quantity restrictions, but cannot control the quality choices of the firms. We inquire about the optimal choice of regulatory regime—whether and under what conditions managed competition or segmentation of the market between regulated monopolies achieves better results. In the spatial duopoly model analyzed here, unhindered competition generally results in an inefficient allocation. When the regulator knows the technologies, optimal managed competition results in distortions of the quality choice, but an optimal regulated-monopolies regime achieves the first best outcome. When the regulator is uncertain about the technologies, neither of these methods yields the first-best outcome. The regulated-monopolies regime still tends to produce better quality choices, but managed competition tends to be more effective at extracting rents from the firms. The overall comparison depends on some finer details of the environment.
Chronic pain increases brainstem proneurotensin/neuromedin-N mRNA expression: a hybridization-histochemical and immunohistochemical study using three different rat models for chronic nociception

The role of neurotensin in the central nervous system is poorly understood. Exogenous neurotensin has potent antinociceptive effects when injected into the midbrain periaqueductal gray (PAG). Although it is present in terminals, fibers and perikarya within the PAG and other midbrain regions known for their antinociceptive circuits, it is not known whether endogenous neurotensin modulates nociception. We examined the midbrain in three different rat models for nociception to learn whether acute or chronic pain altered neuronal levels of the proneurotensin/neuromedin N mRNA (neurotensin mRNA). The models were: adjuvant-induced polyarthritis, adjuvant-induced unilateral paw inflammation, and unilateral peripheral mononeuropathy caused by ligation of the sciatic nerve. Behavioral observations confirmed that the expected symptoms developed as previously described. Within each of the three experimental models, we performed in situ hybridization histochemistry on coronal sections from three midbrain levels that included the rostral one-third of the PAG, the middle one-third of the PAG, and the caudal one-third of the PAG. At the level of the rostral PAG, we found that neither chronic nor acute nociception altered the frequencies or distributions of neurons containing neurotensin mRNA. In contrast, at the levels of the mid- and caudal one third of the PAG, the early effects of the nociceptive lesions differed from the chronic effects. During the acute phase of each model, increases in either the frequency or field area of neurons that were hybridization-positive for neurotensin mRNA were confined to the ventromedial PAG and the dorsal raphe nucleus. As the nociceptive stimuli became chronic, the early increases in neurotensin mRNA-containing neurons at the level of the middle third of the ventral PAG were diminished but remained above control levels, while increases in neurotensin mRNA began to occur in the midbrain tegmentum lateral to the PAG. The most striking increases in neurotensin mRNA expression were observed 16-17 days after the onset of nociceptive stimuli. At the level of the mid-PAG and caudal PAG, increased hybridization signal intensities and neuron frequencies occurred within the nucleus cuneiformis and the lateral tegmental nuclei, including the pedunculopontine and microcellular tegmental nuclei, as well as the deep mesencephalic nuclei. Hybridization-positive neurons in the tegmental nuclei were not observed at early stages of lesion development, but were a consistent feature of caudal midbrains after nociception became chronic.(ABSTRACT TRUNCATED AT 400 WORDS)
Quantum Monte Carlo method using phase-free random walks with slater determinants.

We develop a quantum Monte Carlo method for many fermions using random walks in the space of Slater determinants. An approximate approach is formulated with a trial wave function $|{\ensuremath{\Psi}}_{T}⟩$ to control the phase problem. Using a plane-wave basis and nonlocal pseudopotentials, we apply the method to Be, Si, and P atoms and dimers, and to bulk Si supercells. Single-determinant wave functions from density functional theory calculations were used as $|{\ensuremath{\Psi}}_{T}⟩$ with no additional optimization. The calculated binding energies of dimers and cohesive energy of bulk Si are in excellent agreement with experiments and are comparable to the best existing theoretical results.
Using circuit-level power measurements in household energy management systems

The first requirement for any intelligent household energy management system is to be able to accurately measure energy usage in the home. Measuring energy usage is not difficult, however we must decide what to measure. Whole-home energy measurement is cheap and easy to setup because only one sensor is placed where the home connects to the power grid. The collected data can provide useful information for large appliances. However, the only way to monitor the energy usage of smaller devices is to install an energy meter on every device of interest. This creates a very detailed picture of household energy consumption, but requires a lot of additional hardware---one meter per device in the home. This paper explores an alternative, more practical, approach to monitor household energy usage including small devices. Our approach uses circuit-level power measurements and a new method to separate aggregate data into device-level estimates. Our initial evaluation resulted in an average error less than 5:35% for three devices with good response to changing device state. We therefore believe that this approach, coupled with a device-level control system, would create an ideal architecture for the next generation of household energy management systems.
Cold asymmetrical fermion superfluids

In this work we investigate the general properties and the ground state of an asymmetrical dilute gas of cold fermionic atoms, formed by two particle species having different densities. We have shown in a recent paper, that a mixed phase composed of normal and superfluid components is the energetically favored ground state of such a cold fermionic system. Here we extend the analysis and verify that in fact, the mixed phase is the preferred ground state of an asymmetrical superfluid in various situations. We predict that the mixed phase can serve as a way of detecting superfluidity and estimating the magnitude of the gap parameter in asymmetrical fermionic systems.
Finite temperature structure of the compactified standard model

We analyze the finite temperature structure of the standard model coupled to gravity with one and two dimensions compactified (on a circle and a torus). We find that finite temperature effects wash out any vacua which exist at zero temperature. We also discuss the possibility of transitions between the four-dimensional universe and the lower-dimensional spacetimes.
Bias in a solar constant determination by the Langley method due to structured atmospheric aerosol.

The vertical distribution of the atmospheric aerosol generally differs from the vertical distribution of the molecular atmosphere. The resulting differences in the optical air masses of the aerosol and molecular constituents lead to a bias error in the solar constant inferred by the Langley method. This bias error was calculated for three characteristic aerosol height distributions, and it was found that this error becomes more significant when solar observations taken at large zenith angles are included in the Langley analysis. The bias error is not a sensitive function of wavelength or of the seasonal variation of the molecular atmosphere. Volcanic aerosol injected into the lower stratosphere can lead to large bias errors. These can be reduced significantly by using lidar to provide relatively crude measurements of the vertical distribution of the aerosol extinction coefficient.
Diaromatic Dianionic oxy‐Cope Rearrangement Route to the Synthesis of Bicyclic Ketones

Treatment of dinaphthyl diols of 1,10‐phenanthroline (1) and acenaphthene (2) with nonnucleophilic base gave bicyclic ketones (3) and (4), respectively. The formation of (3) and (4) involves aromat...
Gauge theory, geometry and the large- N limit

We study the relationship between M-theory on a nearly light-like circle and U(N) gauge theory in p + 1 dimensions. We define large-N limits of these theories in which low-energy supergravity is valid. The regularity of these limits implies an infinite series of non-renormalization theorems for the gauge theory effective action, and the leading large-N terms sum to a Born-Infeld form. Compatibility of two different large-N limits that describe the same decompactified M-theory leads to a conjecture for a relation between two limits of string theories.
Regulating the adaptive immune response to respiratory virus infection

Recent years have seen several advances in our understanding of immunity to virus infection of the lower respiratory tract, including to influenza virus infection. Here, we review the cellular targets of viruses and the features of the host immune response that are unique to the lungs. We describe the interplay between innate and adaptive immune cells in the induction, expression and control of antiviral immunity, and discuss the impact of the infected lung milieu on moulding the response of antiviral effector T cells. Recent findings on the mechanisms that underlie the increased frequency of severe pulmonary bacterial infections following respiratory virus infection are also discussed.
Organometallic chemical vapor deposition using allyl precursors

Homoleptic allyl derivatives of many Main-Group and transition metals, M(C3H5)n, are readily available through one-pot syntheses using metal halides and allyl Grignard reagents or by alkylation of alkali-metal salts. The relatively low molecular weight of a C3H5 ligand contributes to high vapor pressures whilst the stability of the allyl radical is predicted to reduce decomposition temperatures. These compounds represent a class of volatile precursors for organometallic chemical vapor deposition (OMCVD) of thin films. Film growth studies using iridium, molybdenum, palladium, platinum, rhodium, selenium, tellurium and tungsten compounds are reviewed and the relationships between pyrolysis pathways and film purity are discussed.
Effects of adopting new precession, nutation and equinox corrections on the terrestrial reference frame

First, the paper is devoted to the effects of adopting new definitive precession and equinox corrections on the terrestrial reference frame: The effect on polar motion is a diurnal periodic term with an amplitude increasing linearly in time; on UT1 it is a linear term. Second, general principles are given the use of which can determine the effects of small rotations (such as precession, nutation or equinox corrections) of the frame of a Conventional Inertial Reference System (CIS) on the frame of the Conventional Terrestrial Reference System (CTS). Next, seven CTS options are presented, one of which is necessary to accommodate such rotations (corrections). The last of these options requiring no changes in the origin of terrestrial longitudes and in UT1 is advocated; this option would be maintained by eventually referencing the Greenwich Mean Sidereal Time to a fixed point on the equator, instead of to the mean equinox of date, the current practice. Accommodating possible future changes in the astronomical nutation is discussed in the last section. The Appendix deals with the effects of differences which may exist between the various CTS's and CIS's (inherent in the various observational techniques) on earth rotation parameters (ERP) and how these differences can be determined. It is shown that the CTS differences can be determined from observations made at the same site, while the CIS differences by comparing the ERP's determined by the different techniques during the same time period.
On-line identification of process models in closed-loop material testing

On-line identification of process models in mechanical material testing situations is considered here. The identification is to be performed under closed loop test conditions and using normally available command signals. Process model forms appropriate for a variety of material testing situations are developed here. The performance of on-line identification schemes is evaluated for some material testing situations, using simulation and experiment. The identification schemes are successful in performing parameter estimation using simple process models.
Valence Bond Theory of Organic Charge-Transfer Salts

Abstract A valence bond (VB) description is introduced for organic charge-transfer (CT) salts based on mixed stacks… D+γA−γD+γA−γ … of donors (D) and acceptors (A). Extrapolating exact results for finite rings shows that the magnetic gap ΔEm is finite for γ γ c as expected in the paramagnetic ionic limit γ= 1. The small finite ΔEm in the “ionic” TMPD-TCNQ complex indicates incomplete CT, in agreement with the resonant Raman result of γ∼ 0.7. The extension of diagrammatic VB techniques to partly-filled segregated ion-radical stacks like … A −γ A −γ A −γ A −γ or … D +γ D +γ D +γ D +γ… is discussed.
Wanna Get Away? Regression Discontinuity Estimation of Exam School Effects Away From the Cutoff

In regression discontinuity (RD) studies exploiting an award or admissions cutoff, causal effects are nonparametrically identified for those near the cutoff. The effect of treatment on inframarginal applicants is also of interest, but identification of such effects requires stronger assumptions than those required for identification at the cutoff. This article discusses RD identification and estimation away from the cutoff. Our identification strategy exploits the availability of dependent variable predictors other than the running variable. Conditional on these predictors, the running variable is assumed to be ignorable. This identification strategy is used to study effects of Boston exam schools for inframarginal applicants. Identification based on the conditional independence assumptions imposed in our framework yields reasonably precise and surprisingly robust estimates of the effects of exam school attendance on inframarginal applicants. These estimates suggest that the causal effects of exam school ...
Secular orbit variation due to solar radiation effects: a detailed model for BYORP

A detailed derivation of the effect of solar radiation pressure on the orbit of a body about a primary orbiting the Sun is given. The result is a set of secular equations that can be used for long-term predictions of changes in the orbit. Solar radiation pressure is modeled as a Fourier series in the body’s rotation state, where the coefficients are based on the shape and radiation properties of the body as parameters. In this work, the assumption is made that the body is in a synchronous orbit about the primary and rotates at a constant rate. This model is used to write explicit variational equations of the energy, eccentricity vector, and angular momentum vector for an orbiting body. Given that the effect of the solar radiation pressure and the orbit are periodic functions, they are readily averaged over an orbit. Furthermore, the equations can be averaged again over the orbit of the primary about the Sun to give secular equations for long-term prediction. This methodology is applied to both circular and elliptical orbits, and the full equations for secular changes to the orbit in both cases are presented. These results can be applied to natural systems, such as the binary asteroid system 1999 KW4, to predict their evolution due to the Binary YORP effect, or to artificial Earth orbiting, nadir-pointing satellites to enable more precise models for their orbital evolution.
Mechanism of the atmospheric oxidation of sulfur dioxide - Catalysis by hydroxyl radicals

A flash photolysis/resonance fluorescence technique was used to investigate the decay of OH due to the reaction OH + SO2 (+M) to HOSO2 (+M). In the presence of small amounts of NO (10 to the 14th per cu cm), the decays deviated from the normal semilogarithmic linearity due to reformation of OH. On the basis of computer simulations of the decay curves, it is suggested that the reactions HOSO2 + O2 to HO2 + SO3 (k3), and HO2 + HO to OH + NO2 are the likely subsequent steps in SO2 oxidation. The upper limit for the binding energy of HOSO2 relative to OH + SO2 is estimated to be 32 kcal/mol. The atmospheric implications of a catalytic oxidation mechanism are briefly discussed.
Enantioselective syntheses of 2-alkyl- and 2,6-dialkylpiperidine alkaloids: preparations of the hydrochlorides of (-)-coniine, (-)-solenopsin A, and (-)-dihydropinidine

[reaction: see text] Sequences of lithiation-substitution, enantioselective hydrogenation, and diastereoselective lithiation-substitution provide efficient highly enantioselective syntheses of 2-substituted and cis and trans 2,6-disubstituted piperidines. The methodology is demonstrated by syntheses of (-)-coniine, (-)-solenopsin A, and (-)-dihydropinidine as their hydrochlorides.
Analysis of Deep Underground Muons

We compare results of Monte Carlo simulations to results from two deep-underground muon experiments. The primary goal is to obtain information about chemical composition of primary cosmic rays with energies around ${10}^{14}$-${10}^{15}$ eV. We also check consistency of the two experiments and study the transverse-momentum distribution of the parent muons.
Transition Metal-Mediated Synthesis of Monocyclic Aromatic Heterocycles

Heterocycles constitute the largest and the most diverse family of organic compounds. Among them, aromatic heterocycles represent structural motifs found in a great number of biologically active natural and synthetic compounds, drugs, and agrochemicals. Moreover, aromatic heterocycles are widely used for synthesis of dyes and polymeric materials of high value. 1 There are numerous reports on employment of aromatic heterocycles as intermediates in organic synthesis. 2 Although, a variety of highly efficient methodologies for synthesis of aromatic heterocycles and their derivatives have been reported in the past, the development of novel methodologies is in cuntinious demand. Particlularly, development of new synthetic approaches toward heterocycles, aiming at achieving greater levels of molecular complexity and better functional group compatibilities in a convergent and atom economical fashions from readily accessible starting materials and under mild reaction conditions, is one of a major research endeavor in modern synthetic organic chemistry. Transition metal-catalyzed transformations, which often help to meet the above criteria, are among the most attractive synthetic tools. Several excellent reviews dealing with transition metal-catalyzed synthesis of heterocyclic compounds have been published in literature during recent years. Many of them highlighted the use of a particular transition metal, such as gold,3 silver,4 palladium,5 copper,6 cobalt,7 ruthenium,8 iron,9 mercury,10 rare-earth metals,11 and others. Another array of reviews described the use of a specific kind of transformation, for instance, intramolecular nucleophilic attack of heteroatom at multiple C–C bonds,12 Sonogashira reaction,13 cycloaddition reactions,14 cycloisomerization reactions,15 C–H bond activation processes,16 metathesis reactions,17 etc. Reviews devoted to an application of a particular type of starting materials have also been published. Thus, for example, applications of isocyanides,18 diazocompounds,19 or azides20 have been discussed. In addition, a significant attention was given to transition metal-catalyzed multicomponent syntheses of heterocycles.21 Finally, syntheses of heterocycles featuring formation of intermediates, such as nitrenes,22 vinylidenes,23 carbenes, and carbenoids24 have also been reviewed. The main focus of the present review is a transition metal-catalyzed synthesis of aromatic monocyclic heterocycles. The organization of the review is rather classical and is based on a heterocycle, categorized in the following order: (a) ring size of heterocycle, (b) number of heteroatoms, (c) type of heterocycle, and (d) a class of transformation involved. A brief mechanistic discussion is given to provide information about a possible reaction pathway when necessary. The review mostly discusses recent literature, starting from 200425 until the end of 2011, however, some earlier parent transformations are discussed when needed.
Efficiency in the savings and loan industry

Abstract The stochastic econometric cost frontier approach is modified to investigate efficiency in mutual and stock S & Ls using 1991 data on U.S. S & Ls. This methodology allows both the cost frontier and error structures to differ between S & Ls of these two ownership forms. A likelihood ratio test indicates that the data support this unrestricted model, which implies efficient mutual and stock S & Ls use different production technologies. Various measures of inefficiency show that on average stock S & Ls are less efficient than mutual S & Ls. The second part of the article relates the inefficiency measures to several correlates.
Filamentary structure of star-forming complexes

The nearest young stellar groups are associated with hubs of column density exceeding 1022 cm?2, according to recent observations. These hubs radiate multiple filaments of parsec length, having lower column density and fewer stars. Systems with many filaments tend to have parallel filaments with similar spacing. Such hub-filament structure is associated with all of the nine young stellar groups within 300 pc, forming low-mass stars. Similar properties are seen in infrared dark clouds forming more massive stars. In a new model, an initial clump in a uniform medium is compressed into a self-gravitating, modulated layer. The outer layer resembles the modulated equilibrium of Schmid-Burgk with nearly parallel filaments. The filaments converge onto the compressed clump, which collapses to form stars with high efficiency. The initial medium and condensations have densities similar to those in nearby star-forming clouds and clumps. The predicted structures resemble observed hub-filament systems in their size, shape, and column density, and in the appearance of their filaments. These results suggest that HFS associated with young stellar groups may arise from compression of clumpy gas in molecular clouds.
The numerical range of nonlinear Banach space operators

Abstract A generalization of Zarantonello's result on the numerical range of a nonlinear Hilbert space-valued operator to the case of the Banach space-valued operator is given.
A New Shear Estimator for Weak-Lensing Observations

We present a new shear estimator for weak-lensing observations that properly accounts for the effects of a realistic point-spread function (PSF). Images of faint galaxies are subject to gravitational shearing, followed by smearing with the instrumental and/or atmospheric PSF. We construct a "finite-resolution shear operator," which when applied to an observed image has the same effect as a gravitational shear applied prior to smearing. This operator allows one to calibrate essentially any shear estimator. We then specialize to the case of weighted second-moment shear estimators. We compute the shear polarizability, which gives the response of an individual galaxy's polarization to a gravitational shear. We then compute the response of the population of galaxies, and thereby construct an optimal weighting scheme for combining shear estimates from galaxies of various shapes, luminosities, and sizes. We define a figure of merit (an inverse shear variance per unit solid angle) that characterizes the quality of image data for shear measurement. The new method is tested with simulated image data. We discuss the correction for anisotropy of the PSF and propose a new technique involving measuring shapes from images that have been convolved with a recircularizing PSF. We draw attention to a hitherto ignored noise-related bias and show how this can be analyzed and corrected for. The analysis here draws heavily on the properties of real PSFs, and we include in Appendix A a brief review, highlighting those aspects that are relevant for weak lensing.
DYNAMICS OF SOLIDS IN THE MIDPLANE OF PROTOPLANETARY DISKS: IMPLICATIONS FOR PLANETESIMAL FORMATION

We present local two-dimensional and three-dimensional hybrid numerical simulations of particles and gas in the midplane of protoplanetary disks (PPDs) using the Athena code. The particles are coupled to gas aerodynamically, with particle-to-gas feedback included. Magnetorotational turbulence is ignored as an approximation for the dead zone of PPDs, and we ignore particle self-gravity to study the precursor of planetesimal formation. Our simulations include a wide size distribution of particles, ranging from strongly coupled particles with dimensionless stopping time τ s ≡ Ωt stop = 10–4 (where Ω is the orbital frequency, t stop is the particle friction time) to marginally coupled ones with τ s = 1, and a wide range of solid abundances. Our main results are as follows. (1) Particles with τ s 10–2 actively participate in the streaming instability (SI), generate turbulence, and maintain the height of the particle layer before Kelvin-Helmholtz instability is triggered. (2) Strong particle clumping as a consequence of the SI occurs when a substantial fraction of the solids are large (τ s 10–2) and when height-integrated solid-to-gas mass ratio Z is super-solar. We construct a toy model to offer an explanation. (3) The radial drift velocity is reduced relative to the conventional Nakagawa-Sekiya-Hayashi (NSH) model, especially at high Z. Small particles may drift outward. We derive a generalized NSH equilibrium solution for multiple particle species which fits our results very well. (4) Collision velocity between particles with τ s 10–2 is dominated by differential radial drift, and is strongly reduced at larger Z. This is also captured by the multi-species NSH solution. Various implications for planetesimal formation are discussed. In particular, we show that there exist two positive feedback loops with respect to the enrichment of local disk solid abundance and grain growth. All these effects promote planetesimal formation.
Living with global imbalances: A contrarian view

Abstract This paper questions three separate but related contentions: that Americans save too little; that the large US current account deficit is unsustainable; and that the Chinese currency (rmb) requires large appreciation. Viewed from the perspective of a knowledge-based economy in a globalized world undergoing dramatic demographic change, Americans save quite enough for the future and the US current account deficit is a natural and indeed an expected phenomenon. It can persist for many years. The current configuration of surpluses and deficits is mutually beneficial so long as Americans continue to invest productively. A significant revaluation of the rmb would yield little benefit and would run a grave risk of precipitating financial crises.