cssi/SciSciGPT-SciSciNet huggingface dataset:
Broadband Internet: net neutrality versus open access

“Network neutrality” and “open access” are two policies designed to preserve openness on the Internet. Open access mandates openness of conduits (e.g. television cable and DSL) to intermediaries (e.g. America Online), while network neutrality mandates openness to advanced content (streaming video, interactive e-commerce, etc.). We develop a systems model with free entry and competition in all three industry segments (conduits, intermediaries, and content) and examine the effects of the two types of regulation. We find that open access does not necessarily result in more openness of content and is not a substitute for network neutrality.
Ca11E3C8 (E = Sn, Pb): New Complex Carbide Zintl Phases Grown from Ca/Li Flux

New carbide Zintl phases Ca11E3C8 (E = Sn, Pb) were grown from reactions of carbon and heavy tetrelides in Ca/Li flux. They form with a new structure type in space group P21/c (a = 13.1877(9)A, b = 10.6915(7)A, c = 14.2148(9)A, β = 105.649(1)°, and R1 = 0.019 for the Ca11Sn3C8 analog). The structure features isolated E4– anions as well as acetylide (C22–) and allenylide (C34–) anions; the vibrational modes of the carbide anions are observed in the Raman spectrum. The charge-balanced nature of these phases is confirmed by DOS calculations which indicate that the tin analog has a small band gap (Eg < 0.1 eV) and the lead analog has a pseudogap at the Fermi level. Reactions of these compounds with water produce acetylene and allene.
Plate tectonics and island arcs

The plate-tectonic concepts that developed rapidly in the late l960s made possible the understanding of island arcs. Before that time, mobilistic concepts evolved slowly, hindered, particularly in the United States, by an obstructionist geoscience establishment. The volcanic belts of island arcs form about 100 km above subducting plates. Convergent-plate boundaries evolve complexly with time and, at any one time, vary greatly along their lengths. Seismicity defines positions, but not trajectories, of descending slabs, which sink more steeply than they dip and are overridden by advancing upper plates. Subduction occurs beneath only one side at a time of an internally rigid plate, and the common regime in an overriding plate, behind a surficial accretionary wedge, is extensional, except where a collision is underway. Back-arc-basin lithosphere is built behind, or by, migrating island arcs, which lengthen and increase their curvatures. A collision can involve two active arcs, in which case, intervening lithosphere sinks beneath both of them, or an active margin and a passive one. Either type of collision generally is followed by the breaking through of new subduction, beneath the composite mass of light crust, from a new trench on the outside of the aggregate; conversely, a new subduction system commonly is a by-product of collision. A strip of back-arc-basin crust is in many cases left attached to the aggregate, in front of the new trench, and becomes the basement for a fore-arc basin, the leading edge of which is raised as melange is stuffed under it. Sedimentation in trenches is predominantly longitudinal and can be from distant sources. Accretionary wedges are dynamic, being thickened at both toes and bottoms by tectonic accretion and thinned by gravitational forward flow; melange is largely a product of tectonic imbrication and flowage driven by these conflicting processes, not of submarine sliding. High-pressure metamorphic rocks form beneath overriding plates, not within wedges in front of them. Arc magmas incorporate much material from the lithosphere through which they rise and vary correspondingly with the evolving composition of that lithosphere. Arc crust is inflated into geanticlines by intrusive rocks and thermal expansion. Submarine island-arc volcanic rocks are widely spilitized, with Na enrichment and Ca depletion, by hydrothermal reaction with sea water. The lower crust of mature island arcs consists of granulite-facies rocks of mafic, intermediate, and felsic-intermediate compositions. The Mohorovicic discontinuity may be primarily a constructional boundary, representing the shallow limit off crystallization of voluminous rocks of ultramafic composition or plagioclase-free mineralogy.
A generator of protein folding kinetics states for the diffusion–collision model

Two separate algorithms for calculating the intermediate states, using cellular automata, and the initial conditions in the rate matrix for the diffusion–collision model are introduced. They enable easy and fast calculations of the folding probabilities of the intermediate states, even for a very large number of microdomains. © 2000 John Wiley & Sons, Inc. J Comput Chem 21: 923–932, 2000
Block copolymer synthesis

The efficient synthesis of structurally well-defined block copolymers is exciting and important area of research. This article describes several methods for the preparation of di- and triblock copolymers. Examples are taken from the literature and include anionic, cationic, free-radical and metal-catalyzed polymerizations that are useful for the preparation of these hybrid materials. In addition, examples that combine these polymerization mechanisms are described.
Hexagon-based all-quadrilateral mesh generation with guaranteed angle bounds

In this paper, we present a novel hexagon-based mesh generation method which creates all-quadrilateral (all-quad) meshes with guaranteed angle bounds and feature preservation for arbitrary planar domains. Given any planar curves, an adaptive hexagon-tree structure is constructed by using the curvature of the boundaries and narrow regions. Then a buffer zone and a hexagonal core mesh are created by removing elements outside or around the boundary. To guarantee the mesh quality, boundary edges of the core mesh are adjusted to improve their formed angles facing the boundary, and two layers of quad elements are inserted in the buffer zone. For any curve with sharp features, a corresponding smooth curve is firstly constructed and meshed, and then another layer of elements is inserted to match the smooth curve with the original one. It is proved that for any planar smooth curve all the element angles are within [60°-e, 120°+e] (e ≤ 5°). We also prove that the scaled Jacobians defined by two edge vectors are in the range of [sin(60°-e), sin90°], or [0.82, 1.0]. Furthermore, the same angle range can be guaranteed for curves with sharp features, with the exception of small angles in the input curve. In addition, all the elements in the final mesh are grouped into five types, and most elements only need a few flops to construct the stiffness matrix for finite element analysis. This will significantly reduce the computational time and the required memory during the stiffness matrix construction. We have applied our algorithm to a set of complicated geometries, including the Lake Superior map, and a three-component air foil with sharp features.
Timing Properties of Magnetars

We study the pulse morphologies and pulse amplitudes of thermally emitting neutron stars with ultrastrong magnetic fields. The beaming of the radiation emerging from a magnetar was recently shown to be predominantly nonradial, with a small pencil and a broad fan component. We show that the combination of this radiation pattern with the effects of strong lensing in the gravitational field of the neutron star yields pulse profiles that show a qualitatively different behavior compared to that of the radially peaked beaming patterns explored previously. Specifically, we find that (i) the pulse profiles of magnetars with a single hot emission region on their surface exhibit 1-2 peaks, whereas those with an antipodal emission geometry have 1-4 peaks, depending on the neutron star compactness, the observer's viewing angle, and the size of the hot regions; (ii) the energy dependence of the beaming pattern may give rise to weakly or strongly energy-dependent pulse profiles and may introduce phase lags between different energy bands; (iii) the nonradial beaming pattern can give rise to high pulsed fractions even for very relativistic neutron stars; (iv) the pulsed fraction may not vary monotonically with neutron star compactness; (v) the pulsed fraction does not decrease monotonically with the size of the emitting region; (vi) the pulsed fraction from a neutron star with a single hot pole has, in general, a very weak energy dependence, in contrast to the case of an antipodal geometry. Comparison of these results to the observed properties of anomalous X-ray pulsars strongly suggests that they are neutron stars with a single hot region of ultrastrong magnetic field.
Turbulent Transport to a Rotating Cylinder for Large Prandtl or Schmidt Numbers

The heat or mass transport to a rotating cylinder is obtained by solving the conservation equations for large Prandtl or Schmidt numbers. A modified mixing length, which includes the effect of centrifugal forces in terms of the Richardson number, is used. Explicit relations are presented for the heat or mass transport and a comparison is made with the experimental data over a range of Prandtl and Schmidt numbers from 190 to 11,000.
An Empirically Calibrated Model for Interpreting the Evolution of Galaxies during the Reionization Era

We develop a simple star formation model whose goal is to interpret the emerging body of observational data of star-forming galaxies at z 6. The efficiency and duty cycle of the star formation activity within dark matter halos are determined by fitting the luminosity functions of Ly? emitter and Lyman break galaxies at redshifts z 5-6. Our error budget takes proper account of the uncertainty arising from both the spatial clustering of galaxies and the Poisson contribution. We find that the abundance of luminous Lyman break galaxies in the 500 Myr between z 6 and 10 can be naturally explained by the hierarchical assembly of dark matter halos; there is only marginal evidence for strong physical evolution. In contrast, the first estimates of the abundance of less luminous star-forming galaxies at z = 9-10 are higher than predicted and, if verified by further data, may suggest a top-heavy stellar mass function at these early epochs. Although these abundances remain uncertain because of the difficulty of spectroscopic confirmation and cosmic variance, even a modest improvement in survey capability with present or upcoming facilities should yield great progress. In this context, we use our model to consider those observational techniques that hold the most promise and make predictions for specific surveys that are, or will soon be, underway. We conclude that narrowband Ly? emitter surveys should be efficient for searches at z 7-8; however, such conventional surveys are unlikely to detect sufficient galaxies at z 10 to provide useful constraints. For this reason, gravitational lensing offers the best prospect for probing the z 10 universe prior to JWST.
Gene Duplication Is an Evolutionary Mechanism for Expanding Spectral Diversity in the Long-Wavelength Photopigments of Butterflies

Butterfly long-wavelength (L) photopigments are interesting for comparative studies of adaptive evolution because of the tremendous phenotypic variation that exists in their wavelength of peak absorbance (lambda(max) value). Here we present a comprehensive survey of L photopigment variation by measuring lambda(max) in 12 nymphalid and 1 riodinid species using epi-microspectrophotometry. Together with previous data, we find that L photopigment lambda(max) varies from 510-565 nm in 22 nymphalids, with an even broader 505- to 600-nm range in riodinids. We then surveyed the L opsin genes for which lambda(max) values are available as well as from related taxa and found 2 instances of L opsin gene duplication within nymphalids, in Hermeuptychia hermes and Amathusia phidippus, and 1 instance within riodinids, in the metalmark butterfly Apodemia mormo. Using maximum parsimony and maximum likelihood ancestral state reconstructions to map the evolution of spectral shifts within the L photopigments of nymphalids, we estimate the ancestral pigment had a lambda(max) = 540 nm +/- 10 nm standard error and that blueshifts in wavelength have occurred at least 4 times within the family. We used ancestral state reconstructions to investigate the importance of several amino acid substitutions (Ile17Met, Ala64Ser, Asn70Ser, and Ser137Ala) previously shown to have evolved under positive selection that are correlated with blue spectral shifts. These reconstructions suggest that the Ala64Ser substitution has indeed occurred along the newly identified blueshifted L photopigment lineages. Substitutions at the other 3 sites may also be involved in the functional diversification of L photopigments. Our data strongly suggest that there are limits to the evolution of L photopigment spectral shifts among species with only one L opsin gene and that opsin gene duplication broadens the potential range of lambda(max) values.
Nonreciprocal Wave Propagation in a Hollow Image Guide with a Ferrite Layer

A hollow image guide with a ferrite layer is studied for its non-reciprocal wave propagation. A method based on the effective dielectric constant approach is used for analysis and design of an isolator. Experimental verification is performed at frequencies around 35 GHz.
Molecular analysis of the myosin gene family in Arabidopsis thaliana

Myosin is believed to act as the molecular motor for many actin-based motility processes in eukaryotes. It is becoming apparent that a single species may possess multiple myosin isoforms, and at least seven distinct classes of myosin have been identified from studies of animals, fungi, and protozoans. The complexity of the myosin heavy-chain gene family in higher plants was investigated by isolating and characterizing myosin genomic and cDNA clones from Arabidopsis thaliana. Six myosin-like genes were identified from three polymerase chain reaction (PCR) products (PCR1, PCR11, PCR43) and three cDNA clones (ATM2, MYA2, MYA3). Sequence comparisons of the deduced head domains suggest that these myosins are members of two major classes. Analysis of the overall structure of the ATM2 and MYA2 myosins shows that they are similar to the previously-identified ATM1 and MYA1 myosins, respectively. The MYA3 appears to possess a novel tail domain, with five IQ repeats, a six-member imperfect repeat, and a segment of unique sequence. Northern blot analyses indicate that some of the Arabidopsis myosin genes are preferentially expressed in different plant organs. Combined with previous studies, these results show that the Arabidopsis genome contains at least eight myosin-like genes representing two distinct classes.
A bijection between dominant Shi regions and core partitions

It is well-known that Catalan numbers C"n=1n+1(2nn) count the number of dominant regions in the Shi arrangement of type A, and that they also count partitions which are both n-cores as well as (n+1)-cores. These concepts have natural extensions, which we call here the m-Catalan numbers and m-Shi arrangement. In this paper, we construct a bijection between dominant regions of the m-Shi arrangement and partitions which are both n-cores as well as (mn+1)-cores. The bijection is natural in the sense that it commutes with the action of the affine symmetric group.
Criteria for conformal invariance of (0, 2) models

Abstract It is argued that many linear (0,2) models flow in the infrared to conformally invariant solutions of string theory. The strategy in the argument is to show that the effective space-time superpotential must vanish because there is no place where it can have a pole. This conclusion comes from either of two different analyses, in which the Kahler class or the complex structure of the gauge bundle is varied, while keeping everything else fixed. In the former case, we recover from the linear sigma model the usual simple pole in the 27 3 Yukawa coupling but show that an analogous pole does not arise in the couplings of gauge singlet modes. In the latter case, a dimension count shows that the world-sheet instanton sum does not “see” the singularities of the gauge bundle and hence cannot have a pole.
Giant Resonance Phenomena in the Electron Impact Ionization of Heavy Atoms and Ions

Heavy atoms and ions offer an interesting opportunity to study atomic physics in a region where the atomic structure is dominated by the interelectronic interactions. One illustration of this is the profound term dependence of atomic orbitals for certain configurations of heavy atoms and ions. This subject is extensively discussed elsewhere in the proceedings to this Institute. The present paper deals with another manifestation of resonance behavior, namely the appearance of giant scattering resonances in the cross sections for ionization of heavy atoms by electron impact. Such resonant structures arise from the double well nature of the scattering potential and have recently been identified in the cross sections for the electron impact ionization of several xenon-like ions.1 In the present report, we summarize the results of calculations showing similar effects for a variety of other ions.
Effect of permanent-magnet irregularities in levitation force measurements

In the measurement of the levitation force between a vertically magnetized permanent magnet (PM) and a bulk high-temperature superconductor (HTS), PM domains with horizontal components of magnetization are shown to produce a non-negligible contribution to the levitation force in most systems. Such domains are typically found in all PMs, even in those that exhibit zero net horizontal magnetic moment. Extension of this analysis leads to an HTS analogue of Earnshaw's theorem, in which the vertical stiffness is equal to the sum of the horizontal stiffness at the field-cooling position, independent of the angular distribution of magnetic moments within the PM.
Resource allocation pattern in infrastructure networks

Most infrastructure networks evolve and operate in a decentralized fashion, which may adversely impact the allocation of resources across the system. Here we investigate this question by focusing on the relation between capacity and load in various such networks. We find that, due to network traffic fluctuations, real systems tend to have larger unoccupied portions of the capacities—smaller load-to-capacity ratios—on network elements with smaller capacities, which contrasts with key assumptions involved in previous studies. This finding suggests that infrastructure networks have evolved to minimize local failures but not necessarily large-scale failures that can be caused by the cascading spread of local damage.
Hydrostatic Gas Journal Bearings for Micro-Turbomachinery

Several years ago an effort was undertaken at MIT to develop high-speed rotating MEMS (Micro Electro-Mechanical Systems) using computer chip fabrication technology. To enable high-power density the micro-turbomachinery must be run at tip speeds of order 500 m/s, comparable to conventional scale turbomachinery. The high rotating speeds (of order 2 million rpm), the relatively low bearing aspect ratios (L/D <0.1) due to fabrication constraints, and the laminar flow regime in the bearing gap place the microbearing designs to an exotic spot in the design space for hydrostatic gas bearings. This paper presents a new analytical model for axially fed gas journal bearings and reports the experimental testing of micro gas bearings to characterize and to investigate their rotordynamic behavior. The analytical model is capable of dealing with all the elements of, (1) micro-devices, (2) dynamic response characteristics of hydrostatic gas bearings, (3) evaluation of stiffness, natural frequency and damping, (4) evaluation of instability boundaries, and (5) evaluation of effects of imbalance and bearing anisotropy. First, a newly developed analytical model for hydrostatic gas journal bearings is introduced. The model consists of two parts, a fluid dynamic model for axially fed gas journal bearings and a rotordynamic model for micro-devices. Next, the model is used to predict the natural frequency, damping ratio and the instability boundary for the test devices. Experiments are conducted using a high-resolution fiber optic sensor to measure rotor speed, and a data reduction scheme is implemented to obtain imbalance-driven whirl response curves. The model predictions are validated against experimental data and show good agreement with the measured natural frequencies and damping ratios. Last, the new model is successfully used to establish bearing operating protocols and guidelines for high-speed operation.
Preparation and NMR Analysis of 2,6-Heterodifunctional Halobenzenes as Precursors for Substituted Biphenyls

Abstract Preparation and complete characterization of 16 2,6-disubstituted halobenzenes, including nine new compounds, from two common starting materials is described. Seven of the new compounds contain one or two propylthio groups, which have been introduced in two ways. Direct reaction of arenediazonium salts with 1-propanethiolate gives yields comparable to those obtained in a three-step method through sulfonyl chlorides. The 1 H- and 13 C NMR chemical shifts of 17 1,2,3-trisubstituted benzenes have been correlated with the predicted values and the observed trends explained using commonly available modeling packages.
Microscopic Study of Semiconductor Heterojunctions - Photoemission Measurement of the Valance-Band Discontinuity and of the Potential Barriers

We report on synchrotron-radiation photoemission measurements of the valence-band discontinuity and of the Fermi-level position for 25 different interfaces involving group-IV, III-V, and II-VI semiconductor substrates and Ge or Si overlayers. A comparison is made between our measured discontinuities and the predictions of current theoretical models. We find the best agreement with empirically corrected versions of the models of Harrison and of Frensley and Kroemer. However, we present a new empirical rule based on our present results and on those of other authors which yields even more accurate predictions of band discontinuities. The measured Fermi-level-pinning position of each substrate is the same for both Ge and Si overlayers. This result is discussed in terms of the “defect model” of Fermi-level pinning, originally developed for Schottky barriers.
Vasculitis in the Geriatric Population

Vasculitis represents an uncommon but important group of disease entities that may affect older patients. The most common vasculitic disease in humans in giant cell arteritis, a disease process seen almost exclusively in patients older than 50 years in age. Vasculitic disease in geriatric patients presents unique challenges with regard to diagnosis and treatment. A thorough understanding of the vasculitic disease entities that may affect older patients as well as their diagnosis and management is essential in minimizing disease and treatment-related morbidity and mortality.
Policy review: the US Affordable Care Act, community health centers, and economic development opportunities

Part of the Patient Protection and Affordable Care Act (ACA) was designed to extend public health care coverage to millions of Americans and will provide states with a fiscal cushion to help achiev...
Single cell visualization of transcription kinetics variance of highly mobile identical genes using 3D nanoimaging

Multi-cell biochemical assays and single cell fluorescence measurements revealed that the elongation rate of Polymerase II (PolII) in eukaryotes varies largely across different cell types and genes. However, there is not yet a consensus whether intrinsic factors such as the position, local mobility or the engagement by an active molecular mechanism of a genetic locus could be the determinants of the observed heterogeneity. Here by employing high-speed 3D fluorescence nanoimaging techniques we resolve and track at the single cell level multiple, distinct regions of mRNA synthesis within the model system of a large transgene array. We demonstrate that these regions are active transcription sites that release mRNA molecules in the nucleoplasm. Using fluctuation spectroscopy and the phasor analysis approach we were able to extract the local PolII elongation rate at each site as a function of time. We measured a four-fold variation in the average elongation between identical copies of the same gene measured simultaneously within the same cell, demonstrating a correlation between local transcription kinetics and the movement of the transcription site. Together these observations demonstrate that local factors, such as chromatin local mobility and the microenvironment of the transcription site, are an important source of transcription kinetics variability.
A journey from Island of knowledge to mutual understanding in global business meetings

Knowledge work increasingly takes place in collaborative events from different and changing workplaces due to mobility, multi-locational, and geographical distribution of team members. What are the key elements to create mutual understanding and make creative collaborative decisions in global business meetings? How can these key elements be designed as shikake nudges to build awareness of the individual and team conditions to help knowledge workers make better work environment choices and reach higher levels of engagement? We addressed this question as a transformative journey from island of knowledge to mutual understanding in the context of collaborative decision making in creative global business meetings. We present a "Six Steps to Engagement" framework that offers three feedback loops as shikake triggers to improve the local and global collaboration context and behavior, and three choice-decision-commitment steps toward improving the work environment and increasing knowledge work productivity. To support this framework, we define the following: (1) mutual understanding metrics (MUM) and method for self-assessment and 360 team assessment that define different MUM stages in the journey from island of knowledge to mutual understanding; and (2) an engagement Matrix of Choices (eMoC) prototype to assist geographically distributed knowledge workers to make explicit choices with an understanding of the potential level of engagement and collaboration they can achieve and the respective enablers and hindrances. We argue that iterative and continuous MUM assessment and explicit eMoC choices are central to achieve mutual understanding, high-performance teamwork, and eliminate rework, coordination, and decision wait time. This iterative process (1) allows team members to build awareness of their local conditions and make their local conditions transparent and visible to the rest of the team; (2) provides a feedback mechanism that indicates the engagement potential of each team member and the team, as well as a trigger or nudge toward moving to higher levels of engagement; (3) leads to the alignment of expectations and synchronicity of potential engagement levels.
Supersymmetry and the Atiyah-Singer index theorem

Using a recently introduced index for supersymmetric theories, we present a simple derivation of the Atiyah-Singer index theorem for classical complexes and itsG-index generalization using elementary properties of quantum mechanical supersymmetric systems.
A computer with hands, eyes, and ears

The anthropomorphic terms of the title may suggest an interest in machines that look or act like men. To this extent it is misleading. Our interest is in extending the range of tasks to which machines can be applied to include those that, when performed by a human, require coordination between perceptual and motor processes. We attempt to suppress the egocentric idea that man performs these tasks in the best of all possible ways.
NON-GAUSSIANITY OF THE COSMIC BARYON FLUID : LOG-POISSON HIERARCHY MODEL

In the nonlinear regime of cosmic clustering, the mass density field of the cosmic baryon fluid is highly non-Gaussian. It shows different dynamical behavior from collisionless dark matter. Nevertheless, the evolved field of the baryon fluid is scale-covariant in the range from the Jeans length to a few tens of h−1 Mpc, within which the dynamical equations and initial perturbations are scale free. We show that in the scale-free range, the non-Gaussian features of the cosmic baryon fluid, governed by the Navier-Stokes equation in an expanding universe, can be well described by a log-Poisson hierarchical cascade. The log-Poisson scheme is a random multiplicative process (RMP), which causes non-Gaussianity and intermittency even when the original field is Gaussian. The log-Poisson RMP contains two dimensionless parameters: β for the intermittency and γ for the most singular structure. All the predictions given by the log-Poisson RMP model, including the hierarchical relation, the order dependence of the intermittent exponent, the moments, and the scale-scale correlation, are in good agreement with the results given by hydrodynamic simulations of the standard cold dark matter model. The intermittent parameter β decreases slightly at low redshift and indicates that the density field of the baryon fluid contains more singular structures at lower redshifts. The applicability of the model is addressed.
Detailed chemical kinetic oxidation mechanism for a biodiesel surrogate

A detailed chemical kinetic mechanism has been developed and used to study the oxidation of methyl decanoate, a surrogate for biodiesel fuels. This model has been built by following the rules established by Curran and co-workers for the oxidation of n-heptane and it includes all the reactions known to be pertinent to both low and high temperatures. Computed results have been compared with methyl decanoate experiments in an engine and oxidation of rapeseed oil methyl esters in a jet-stirred reactor. An important feature of this mechanism is its ability to reproduce the early formation of carbon dioxide that is unique to biofuels and due to the presence of the ester group in the reactant. The model also predicts ignition delay times and OH profiles very close to observed values in shock tube experiments fueled by n-decane. These model capabilities indicate that large n-alkanes can be good surrogates for large methyl esters and biodiesel fuels to predict overall reactivity, but some kinetic details, including early CO2 production from biodiesel fuels, can be predicted only by a detailed kinetic mechanism for a true methyl ester fuel. The present methyl decanoate mechanism provides a realistic kinetic tool for simulation of biodiesel fuels.
Estimating Parameters of Short-Term Real Interest Rate Models

This paper sheds light on a narrow but crucial question in finance: What should be the parameters of a model of the short-term real interest rate? Although models for the nominal interest rate are well studied and estimated, dynamics of the real interest rate are rarely explored. Simple ad hoc processes for the short-term real interest rate are usually assumed as building blocks for more sophisticated models. In this paper, parameters of the real interest rate model are estimated in the broad class of single-factor interest rate diffusion processes on U.S. monthly data. It is shown that the elasticity of interest rate volatility — the relationship between the volatility of changes in the interest rate and its level — plays a crucial role in explaining real interest rate dynamics. The empirical estimates of the elasticity of the real interest rate volatility are found to be about 0.5, much lower than that of the nominal interest rate. These estimates show that the square root process, as in the Cox-Ingersoll-Ross model, provides a good characterization of the short-term real interest rate process.
Oxidation of carbon-silicon bonds: the dramatic advantage of strained siletanes.

Herein we report on the use of siletanes as substrates for the oxidation of carbon−silicon bonds. These tetraalkylsilanes are easy to handle yet susceptible to rapid ring opening and oxidation upon exposure to aqueous fluoride and peroxide. This combination of stability and reactivity presents many practical benefits, including compatibility with silicon protecting groups and electron-rich aromatic rings.
From women's suffrage to reproduction rights? Cross-national considerations.

While women's suffrage has become completely institutionalized around the world, liberalized abortion is one indicator of the status of women that remains contested. Moreover, abortion rights differ fundamentally from women's suffrage in that they are not derivative of rights originally extended to men. In this article, we summarize and compare the results of prior studies that assess the effects of independence era, international linkages, modernization, state activism, and status of women on the rate of the adoption of women's suffrage and reproduction rights. We argue that world cultural models of progress and justice foster expanded models of political citizenship; these then provide more compelling rationales for further women's rights.
A one-dimensional model to study collective effects in stellar dynamics☆

Metaequilibrium state of one-dimensional star gas computed for interesting initial conditions corresponds to minimum energy configuration
Control of Regiochemistry, Stereochemistry and Stoichiometry in Additions to Alkadiynes. Synthetic Value of a Sulfone Function

Abstract The strategic placement of a sulfone function alpha to a conjugated alkadiyne is shown to enforce total control of regiochemistry, stereochemistry and stoichiometry in additions of nucleophiles across the triple bonds.
Reduction of O2 to Superoxide Anion (O2•-) in Water by Heteropolytungstate Cluster-Anions

Fundamental information concerning the mechanism of electron transfer from reduced heteropolytungstates (POM(red)) to O2, and the effect of donor-ion charge on reduction of O2 to superoxide anion (O2.-), is obtained using an isostructural series of 1e--reduced donors: alpha-X(n+)W12O40(9-n)-, X(n+) = Al3+, Si4+, P5+. For all three, a single rate expression is observed: -d[POM(red)]/dt = 2k12[POM(red)][O2], where k12 is for the rate-limiting electron transfer from POM(red) to O2. At pH 2 (175 mM ionic strength), k12 increases from 1.4 +/- 0.2 to 8.5 +/- 1 to 24 +/- 2 M-1s-1 as Xn+ is varied from P5+ (3red) to Si4+ (2red) to Al3+ (1red). Variable-pH data (for 1red) and solvent-kinetic isotope (KIE = kH/kD) data (all three ions) indicate that protonated superoxide (HO2.) is formed in two steps--electron transfer, followed by proton transfer (ET-PT mechanism--rather than via simultaneous proton-coupled electron transfer (PCET). Support for an outersphere mechanism is provided by agreement between experimental k12 values and those calculated using the Marcus cross relation. Further evidence is provided by the small variation in k12 observed when Xn+ is changed from P5+ to Si4+ to Al3+, and the driving force for formation of O2.- (aq), which increases as cluster-anion charge becomes more negative, increases by nearly +0.4 V (a decrease of >9 kcal mol-1 in DeltaG degrees ). The weak dependence of k12 on POM reduction potentials reflects the outersphere ET-PT mechanism: as the anions become more negatively charged, the "successor-complex" ion pairs are subject to larger anion-anion repulsions, in the order [(3(ox)3-)(O2.-)]4- < [(2(ox)4-)(O2.-)]5- < [(1(ox)5-)(O2.-)]6-. This reveals an inherent limitation to the use of heteropolytungstate charge and reduction potential to control rates of electron transfer to O2 under turnover conditions in catalysis.
A Stringent Constraint on Alternatives to a Massive Black Hole at the Center of NGC 4258

There is now dynamical evidence for massive dark objects at the center of several galaxies, but suggestions that these are supermassive black holes are based only on indirect astrophysical arguments. As emphasized by Kormendy and Richstone, large M/L ratios and gas motions of order ≈103 km s-1 do not uniquely imply a massive black hole (BH), and it is possible that the central dark objects in these galaxies are massive clusters of stellar remnants, brown dwarfs, low-mass stars, or halo dark matter. The recent unprecedented measurement of the rotation curve of maser emission sources at the center of NGC 4258, and the remarkable discovery that it is Keplerian to high precision, provide us with a unique opportunity for testing alternatives to a BH. We use a conservative upper limit on the systematic deviation from a Keplerian rotation curve to constrain the mass distribution at the galaxy center. Based on evaporation and physical collision timescale arguments, we show that a central cluster is firmly ruled out, unless the cluster consists of extremely dense objects with mass 0.03 M☉ (e.g., low-mass BHs or elementary particles). Since both of these dynamically allowed systems are very improbable for other astrophysical reasons, we conclude that a central dense cluster at the center of NGC 4258 is very improbable, thus leaving the alternative possibility of a massive BH. We also show that the mass of the BH must be 98% of the mass enclosed within the inner edge of the masering disk (3.6 × 107 M☉). A substantial contribution to that mass from a density cusp in the background mass distribution is excluded.
Reionization Constraints from Five-Year WMAP Data

We study the constraints on reionization from 5 years of WMAP data, parameterizing the evolution of the average fraction of ionized hydrogen with principal components that provide a complete basis for describing the effects of reionization on large-scale E-mode polarization. Using Markov Chain Monte Carlo methods, we find that the resulting model-independent estimate of the total optical depth is nearly twice as well determined as the estimate from 3 year WMAP data, in agreement with simpler analyses that assume instantaneous reionization. The mean value of the optical depth from principal components is slightly larger than the instantaneous value; we find τ = 0.097 ± 0.017 using only large-scale polarization, and τ = 0.101 ± 0.019 when temperature data is included. Scale-invariant ns = 1 spectra are allowed by WMAP for exotic ionization histories with large, sudden changes in the ionized fraction at high redshift, but more realistic models still favor a red spectral tilt. Higher moments of the ionization history show less improvement in the 5 year data than the optical depth. By plotting the distribution of polarization power for models from the MCMC analysis, we show that extracting most of the remaining information about the shape of the reionization history from the CMB requires better measurements of E-mode polarization on scales of l ~ 10–20. Conversely, the quadrupole and octopole polarization power is already predicted to better than cosmic variance given any allowed ionization history at z < 30 so that more precise measurements will test the ΛCDM paradigm.
Implicit unstructured Navier-Stokes simulation of leading edge separation over a pitching airfoil

Abstract The two-dimensional laminar flow over a pitching airfoil is simulated using an implicit unstructured grid Navier-Stokes algorithm. The inviscid and viscous fluxes are represented using second-order accurate discretizations employing Roe's method and Gauss' theorem, respectively. The temporal integration is an implicit first-order backward Euler differencing. The linear system arising from the discretization for the governing equations is solved using preconditioned BI-CGSTAB, with the incomplete factorization of the Jacobian used as the preconditioning matrix. Computations are presented for a NACA0012 airfoil pitching about the quarter-chord at a freestream Mach number M∞ = 0.2 and Reynolds numbers Rec = 104 and 2 × 104 at a dimensionless pitching rate Ω 0 + = 2.0 . The results for Rec = 104 are in excellent agreement with previous computations using an explicit unstructured Navier-Stokes algorithm. New results for Rec = 2 × 104 indicate that the principal effect of increasing Reynolds number is to reduce the angle at which the primary recirculation region appears, and to cause it to form closer to the leading edge. This trend, confirmed by a grid refinement study, is consistent with previous results obtained at M∞ = 0.5.
Intramolecular Pd(II)-Catalyzed Aerobic Oxidative Amination of Alkenes: Synthesis of Six-Membered N-Heterocycles

Use of a base-free Pd(DMSO)2(TFA)2 catalyst system enables the synthesis of six-membered nitrogen heterocycles via a Wacker-type aerobic oxidative cyclization of alkenes bearing tethered sulfonamides. Various heterocycles, including morpholines, piperidines, piperazines, and piperazinones, are accessible by this method.
Small scale H I structure and the soft X-ray background

The observed anticorrelation between diffuse soft X-ray flux and H I column density has been explained as absorption of soft X-rays produced in a hot galactic halo, assuming that the neutral interstellar material is sufficiently clumped to reduce the soft X-ray absorption cross section by a factor of two to three. A 21 cm emission line study of H I column density variations at intermediate and high galactic latitudes to 10' spatial resolution has been done. The results confirm conclusions from preliminary work at coarser resolution, and in combination with other data appear to rule out the hypothesis that clumping of neutral interstellar matter on any angular scale significantly reduces X-ray absorption cross sections in the 0.13 - 0.28 keV energy range. It is concluded therefore that the observed anticorrelation is not primarily a consequence of absorption of soft X-rays produced in a hot galactic halo.
Hadronic forward scattering: Predictions for the Large Hadron Collider and cosmic rays

Abstract The status of hadron–hadron interactions is reviewed, with emphasis on the forward and near-forward scattering regions. Using unitarity, the optical theorem is derived. Analyticity and crossing symmetry, along with integral dispersion relations, are used to connect particle–particle and antiparticle–particle total cross sections and ρ -values, e.g., σ pp , σ p ¯ p , ρ pp and ρ p ¯ p , where ρ is the ratio of the real to the imaginary portion of the forward scattering amplitude. Real analytic amplitudes are then introduced to exploit analyticity and crossing symmetry. Again, from analyticity, finite energy sum rules (FESRs) are introduced from which new analyticity constraints are derived. These new analyticity conditions exploit the many very accurate low-energy experimental cross sections, i.e., they constrain the values of the asymptotic cross sections and their derivatives at low energies just above the resonance regions, allowing us new insights into duality. A robust fitting technique—using a minimization of the Lorentzian squared followed by the “Sieve” algorithm—is introduced in order to ‘clean up’ large data samples that are contaminated by outliers, allowing us to make much better fits to hadron–hadron scattering data over very large regions of energy. Experimental evidence for factorization theorems for γ γ , γ p and nucleon–nucleon collisions is presented. The Froissart bound is discussed—what do we mean here by the saturation of the Froissart bound? Using our analyticity constraints, new methods of fitting high-energy hadronic data are introduced which result in much more precise estimates of the fit parameters, allowing accurate extrapolations to much higher energies. It's shown that the γ p , π ± p and nucleon–nucleon cross sections all go asymptotically as ln 2 s , saturating the bound, while conclusively ruling out ln s and s α ( α ∼ 0.08 ) behavior. Implications of this saturation for predictions of σ pp and ρ pp at the Large Hadron Collider (LHC) and for cosmic rays are given. We discuss present day cosmic ray measurements, what they measure and how they deduce p–air cross sections. Connections are made between very high-energy measurements of σ p – air prod —which have rather poor energy determination—and predictions of σ p – air prod obtained, using a Glauber model, from values of σ pp that are extrapolated from fits of accelerator data at very precisely known, albeit lower, energies.
Sonogashira Coupling of Functionalized Trifloyl Oxazoles and Thiazoles with Terminal Alkynes: Synthesis of Disubstituted Heterocycles

This paper describes Sonogashira cross-coupling of functionalized 2-, 4-, and 5-trifloyl oxazoles and thiazoles with terminal alkynes. This methodology has been extended to 2,4-ditrifloylthiazoles, which results in regioselective cross-coupling at the C2-position of the thiazole. The resulting 2-alkynyl-4-trifloylthiazoles are effective electrophiles in a second palladium(0)-mediated cross-coupling reaction.
Another look at non-renewable resource exhaustion

This paper challenges the widely held hypothesis, considered in some circles as accepted scientific consensus, that modern industrial society is rapidly exhausting non-renewable resources. We argue that this paradigm is amiss and use copper availability as an example to demonstrate the problems with this consensus. In the 80 years for which reasonably reliable estimates of copper reserves and reserve life are available, there is no evidence of resource exhaustion. In addition, an analysis of the economics of resource exploration indicates that mining companies will treat exploration as an inventory control problem and trade off using limited capital resources between expanding inventories of reserves and generating current revenue through production. In the case of the copper industry, it is argued that there is little incentive for major copper producers to explore for more resources. Non-producers, exploration companies do have an incentive for expanding reserves, but this does not change the conclusion that new copper resources are effectively not worth looking for. We also conjecture that, except for in rare and temporary circumstances, this conclusion is applicable to many non-renewable resources. Ultimately, this implies that aggregate reserve-life calculations for all types of non-renewable resources are inherently flawed.
Design of compressed truncated perfect nozzles

An analysis is presented for designing and predicting the performance of compressed truncated perfect nozzles. A study was performed to determine the relative merits of such nozzles compared to Rao nozzles. It was found that Rao nozzles always yield higher performance than compressed truncated perfect nozzles. However, the performance differences are quite small (0.04-0.34%), which shows that compressed truncated perfect nozzles are good propulsive nozzles. For nozzle envelopes for which the Rao nozzle design concept fails, compressed truncated perfect nozzles may yield very efficient nozzle designs.
Synthesis and aromatization of 2+2 cycloadducts of butadienes and tetrafluoroethylene

Abstract Passing tetrafluoroethylene (TFE) and hydrocarbon dienes down a hot tube at 600 °C with a contact time of a few seconds produces substituted fluorobenzenes. Specifically, tetrafluoroethylene and butadiene form 1,2-difluorobenzene. The aromatics produced by the pyrolysis of TFE and methyl-substituted butadienes do not necessarily result from eliminating HF from the 2+4 adducts of the starting materials. Solid-acids such as alumina or silica/alumina accelerate the ring-expansion elimination of the 2+2 cycloadducts. Aromatic products result from the preformed 2+2 cycloadducts at temperatures 200 °C lower than the corresponding thermal reaction. The solid-acids can also influence product regiochemistry.
Large scale structure by global monopoles and cold dark matter

A cosmological model in which the primordial perturbations are provided by global monopoles and in which the dark matter is cold has several interesting features. The model is normalized by choosing its single parameter within the bounds obtained from gravitational wave constraints and by demanding coherent velocity flows of about 600 km/sec on scales of 50h-1Mpc. Using this normalization, the model predicts the existence of dominant structures with mass 2×1016M⊙ on a scale 35h-1Mpc, i.e., larger than the horizon at tep. The magnitude of the predicted mass function in the galactic mass range is in good agreement with the observed Schechter function.