cssi/SciSciGPT-SciSciNet huggingface dataset:
Summary of reference materials for the determination of the nutrient composition of foods

Certified reference materials (CRMs) play a critical role in validating the accuracy of nutrient data for food samples. A number of available food CRMs of differing matrix composition have assigned concentrations for various nutrients, along with associated uncertainty intervals (UIs) for those values. These CRMs have been used extensively in the United States Department of Agriculture’s (USDA) ongoing National Food and Nutrient Analysis Program (NFNAP) to monitor the accuracy of assays of key foods and nutrients consumed in the United States. A total of 690 assigned values for individual nutrients, including proximates, vitamins, macroelements, microelements, fatty acids, amino acids, and selected phytochemicals (e.g., carotenoids), were compiled from the certificates of analysis for 63 CRMs, and the specified UI in each case was expressed as a percentage of the assigned certified or reference concentration. Across all nutrients, 63.5% of the UIs were less than 10% of the assigned value, 25.5% were 10–20%, and 11% were greater than 20% of the assigned value. The UIs for proximates, minerals, and trace elements were most consistently less than 10% of the assigned value. The relative uncertainties were significantly higher for vitamins, suggesting greater challenges in measuring and certifying these components. These high UIs (greater than 10% assigned value) in the best available reference materials are likely to be indicative of the precision and accuracy that can be obtained by current measurement systems for these components. These data suggest that care must be taken in choosing CRMs to monitor food composition analysis, including evaluating what levels of uncertainty are required in assigned values and which analytical measurement systems for food components need closer examination and improvement.
Tip110 Protein Binds to Unphosphorylated RNA Polymerase II and Promotes Its Phosphorylation and HIV-1 Long Terminal Repeat Transcription

Transcription plays an important role in both HIV-1 gene expression and replication and mandates complicated but coordinated interactions between the host and virus. Our previous studies have shown that an HIV-1 Tat-interacting protein of 110 kDa, Tip110, binds to and enhances Tat function in Tat-mediated HIV-1 gene transcription and replication (Liu, Y., Li, J., Kim, B. O., Pace, B. S., and He, J. J. (2002) HIV-1 Tat protein-mediated transactivation of the HIV-1 long terminal repeat promoter is potentiated by a novel nuclear Tat-interacting protein of 110 kDa, Tip110. J. Biol. Chem. 277, 23854–23863). However, the underlying molecular mechanisms by which this takes place were not understood. In this study, we demonstrated that Tip110 bound to unphosphorylated RNA polymerase II (RNAPII) in a direct and specific manner. In addition, we detected Tip110 at the HIV-1 long terminal repeat (LTR) promoter and found that Tip110 expression was associated with increased phosphorylation of serine 2 of the heptapeptide repeats within the RNAPII C-terminal domain and increased recruitment of positive transcription elongation factor b to the LTR promoter. Consistent with these findings, we showed that Tip110 interaction with Tat directly enhanced transcription elongation of the LTR promoter. Taken together, these findings have provided additional and mechanistic evidence to support Tip110 function in HIV-1 transcription.
Micromechanical modeling of damage growth in titanium based metal-matrix composites

Abstract The thermomechanical behavior of continuous-fiber reinforced titanium based metal-matrix composites (MMC) is studied using the finite element method. Fiber and interface failures are modeled as discrete damage. The evolution of matrix failure is considered as continuum damage. A thermovis-coplastic unified state variable constitutive theory is employed to capture inelastic and strain-rate sensitive behavior in the Timetal®-21 s matrix. The SCS-6 fibers are modeled as thermoplastic and can fail at some prescribed plastic strain to failure. The effects of residual stresses generated during the consolidation process on the tensile response of the composites are considered. Unidirectional and cross-ply geometries are studied. Differences between the tensile responses in composites with perfectly bonded, weakly bonded and completely debonded fiber/matrix interfaces are discussed.
Adaptive Detection of Signals in Impulsive Noise Environments

A detector structure and an adaptive algorithm are proposed for the reception of signals in noise backgrounds possessing broad-tailed probability distributions typical of impulsive noise. The adaptive detector combines the best features of linear matched filtering and hard-limiting receiver structures resulting in a small-signal SNR performance which is an improvement over either of these detectors alone. Furthermore, the adaptive detector is relatively easy to implement and is shown to provide efficient and robust performance for a wide range of underlying noise distributions.
An Identification-Based Model of Supplier-Retailer Communication

ABSTRACT The theoretical basis of the current thinking on supplier-retailer communication is refined and an alternative model is offered and empirically tested. It is argued and empirically demonstrated that identification is an important mediator in bringing about relational outcomes in a supplier-retailer relationship. Specifically, collaborative communication (higher rather than lower frequency, informality, bidirectionality, and indirectness of communication) from the suppliers is found to be positively related to their coordination with the retailers directly and indirectly through identification, trust, and commitment.
The bottleneck conjecture

The Mahler volume of a centrally symmetric convex body K is dened as M(K )=( Vol K)(VolK). Mahler conjectured that this volume is minimized when K is a cube. We introduce the bottleneck conjecture, which stipulates that a certain convex body K } KK has least volume when K is an ellip- soid. If true, the bottleneck conjecture would strengthen the best current lower bound on the Mahler volume due to Bourgain and Milman. We also generalize the bottleneck conjecture in the context of indenite orthogonal geometry and prove some special cases of the generalization. This article is in the xxx archive as: math.MG/9811119
Sharing geoscience algorithms in a Web service-oriented environment (GRASS GIS example)

Effective use of the large amounts of geospatial data available for geospatial research and applications is needed. In this paper, the emerging SOAP-based Web service technologies have been used to develop a large number of standard compliant, chainable geospatial Web services, using existing geospatial modules in software systems or specific geoscientific algorithms. A prototype for wrapping legacy software modules or geoscientific algorithms into loosely coupled Web services is proposed from an implementation viewpoint. Module development for Web services adheres to the Open GIS Consortium (OGC) geospatial implementation and the World Wide Web consortium (W3C) standards. The Web service interfaces are designed using Web Services Description Language (WSDL) documents. This paper presents how the granularity of an individual existing geospatial service module used by other geoscientific workflows is decided. A treatment of concurrence processes and clustered deployment of Web services is used to overcome multi-user access and network speed limit problems. This endeavor should allow extensive use of geoscientific algorithms and geospatial data.
Convergence analysis of a domain decomposition paradigm

We describe a domain decomposition algorithm for use in several variants of the parallel adaptive meshing paradigm of Bank and Holst. This algorithm has low communication, makes extensive use of existing sequential solvers, and exploits in several important ways data generated as part of the adaptive meshing paradigm. We show that for an idealized version of the algorithm, the rate of convergence is independent of both the global problem size N and the number of subdomains p used in the domain decomposition partition. Numerical examples illustrate the effectiveness of the procedure.
A generalized approach to direction finding

With reference to the recently developed estimation of signal parameters using a rotational invariance techniques (ESPRIT) it is pointed out that other operators can be used to generate the matrix pencil. By way of example, the moving window operator is discussed. >
Micro and macro elasticities in a life cycle model with taxes

We build a life cycle model of labor supply that incorporates changes along both the intensive and extensive margin and use it to assess the consequences of changes in tax and transfer policies on equilibrium hours of work. We find that changes in taxes have large aggregate effects on hours of work. Moreover, we find that there is no inconsistency between this result and the empirical finding of small labor elasticities for prime age workers. In our model, micro and macro elasticities are effectively unrelated. Our model is also consistent with other cross-country patterns.
Electronic structure calculations of vacancies and their influence on materials properties

We provide two examples to illustrate how electronic structure calculations contribute to our understanding of vacancies and their role in determining materials properties. Diffusion and electromigration in aluminium are known to depend strongly on vacancies. Electronic structure calculations show that the vacancy-impurity interaction oscillates with distance, and this leads to an explanation for both the increased electromigration resistance and the slow impurity diffusion for copper in aluminium. Calculations of vacancies in plutonium have been used in conjunction with positron annihilation lifetime measurements to identify the presence of helium-filled vacancies. Helium stabilization of vacancies can provide the precursor for subsequent vacancy-related changes in materials properties.
Sensitivity study on hydraulic well testing inversion using simulated annealing

Cluster variable aperture (CVA) simulated annealing has been used as an inversion technique to construct fluid flow models of fractured formations based on transient pressure data from hydraulic tests. A two-dimensional fracture network system is represented as a filled regular lattice of fracture elements. The algorithm iteratively changes element apertures for a cluster of fracture elements in order to improve the match to observed pressure transients. Aperture size is chosen randomly from a list of discrete apertures. The cluster size is held constant throughout the iterations. Since hydraulic inversion is inherently nonunique, it is important to use additional information. We investigated the relationship between the scale of heterogeneity and the optimal cluster size and shape to enhance convergence of the inversion and improve the results. In a spatially correlated transmissivity field, a cluster size corresponding to about 20 % to 40 % of the practical range of the spatial correlation is optimal. Inversion results of the Raymond test site data are also presented and based on an optimal cluster size; the practical range of the spatial correlation is estimated to be 5 to 10 m.
Observing the Ultrahigh Energy Universe with OWL Eyes

The goal of the Orbiting Wide-field Light-collectors (0WL) mission is to study the origin and physics of the highest energy particles known in nature, the ultra- high energy cosmic rays (UHECRs). The OWL mission consists of telescopes with UV sensitive cameras on two satellites operating in tandem to view in stereo the development of the giant particle showers induced in the Earth s atmosphere by UHECRs. This paper discusses the characteristics of the 0WL mission.
Asset prices and business cycles under market incompleteness

Abstract In this paper, we study the quantitative implications of a real business cycle model where the firm is the capital owner, households are heterogeneous, and markets are incomplete due to restricted asset trade. Since, under these assumptions, the usual firm objective is no longer well defined, several non-standard objectives are incorporated into the model. These include variants of market value maximization and a utility function for the firm. We find that the presence of market incompleteness alters little the behavior of asset returns. On the other hand, the behavior of the macroeconomic aggregates is quite sensitive to the firm objective, which affects the capital accumulation path. In contrast to conventional findings, capital is not necessarily higher when markets are incomplete. In addition, the different capital accumulation effects imply that shareholders with different asset wealth might prefer different firm objectives.
Regularized Determinants of the Laplacian for cofinite kleinian groups with Finite-Dimensional Unitary Representations

For cofinite Kleinian groups (or equivalently, finite-volume three-dimensional hyperbolic orbifolds) with finite-dimensional unitary representations, we evaluate the regularized determinant of the Laplacian using W. Muller’s regularization. We give an explicit formula relating the determinant to the Selberg zeta-function.
Peer effects and multiple equilibria in the risky behavior of friends

We study social interactions in the initiation of sex and other risky behaviors by best friend pairs in the Add Health panel. Focusing on friends with minimal experience at the baseline interview, we estimate bivariate ordered-choice models that include both peer effects and unobserved heterogeneity. We find significant peer effects in sexual initiation: the likelihood of initiating intercourse within a year increases by almost 5 percentage points (on an 11% base rate) if one's friend also initiates intercourse. Similar effects are present for smoking, marijuana use, and truancy. We find larger effects for females and important asymmetries in nonreciprocated friendships.
Listeners' Identification of Environmental Sounds:

To determine if listeners can accurately identify various environmental sounds, a total of 40 sounds, including animal, inanimate, musical, and human sounds, were recorded, randomly arranged on a master tape, and presented to 30 judges for identification. Analysis indicated that, in general, listeners can accurately identify environmental sounds. However, their accuracy was not equal for all four classes of sounds investigated: human sounds yielded the highest accuracy, followed by musical and inanimate sounds, and animal sounds were least accurately identified. Implications and suggestions for research are discussed.
Effect of water-assisted radio frequency heat treatment on the quality of ‘Fuyu’ persimmons

Water-assisted radio frequency (RF) heating was studied as a potential alternative to chemical fumigation for providing quarantine security against Mexican fruit fly (Anastrepha ludens) in ‘Fuyu’ persimmons. Three holding times were chosen for each of the three treatment temperatures (46, 48 and 50 °C), one time at, one above and another below 100% insect mortality. Heat-treatment protocols included preheating the fruit in 40 °C water, followed by RF heating in a 12 kW, 27.12 MHz RF system, holding at the target temperature for the required time and then hydrocooling at 4 °C for 30 min. The preheating time at 40 °C was determined based on the final RF heating uniformity over the fruit cross-section. Quality parameters, including weight loss, firmness, soluble solids, titratable acidity, peel and pulp colour and calyx browning of persimmons, were evaluated after 7 days at room temperature (22 °C) or in cold storage (4 °C). All treatments except for one condition (48 °C+8 min holding) had no significantly adverse effects on quality attributes. Slight calyx browning was observed in the treated samples and the degree of browning increased with the treatment time for each treatment temperature. The results suggested that water-assisted RF heat treatments provided the potential for disinfestation of persimmons with acceptable product quality.
Hyperentangled Bell-state analysis

It is known that it is impossible to unambiguously distinguish the four Bell states encoded in pairs of photon polarizations using only linear optics. However, hyperentanglement, the simultaneous entanglement in more than one degree of freedom, has been shown to assist the complete Bell analysis of the four Bell states (given a fixed state of the other degrees of freedom). Yet introducing other degrees of freedom also enlarges the total number of Bell-like states. We investigate the limits for unambiguously distinguishing these Bell-like states. In particular, when the additional degree of freedom is qubitlike, we find that the optimal one-shot discrimination schemes are to group the 16 states into seven distinguishable classes, and that an unambiguous discrimination is possible with two identical copies.
DETERMINATION OF RHEOLOGICAL AND MAGNETIC PROPERTIES FOR MAGNETORHEOLOGICAL COMPOSITES VIA SHEAR MAGNETIZATION MEASUREMENTS

Anisotropic solid-state magnetorheological (MR) composites are prepared by applying magnetic fields to isotropic suspensions in polymer melts and preserved by cross-linking the melts. The composities are studied through a continuum-level perspective at various magnetic field strengths under oscillatory shear. The minimum number of constraints are applied in the derivation of the magnetic and rheological invariants, which relate the measured macroscopic magnetostriction coefficients to the discrete parameters of any microscopic model. The field-induced stress is defined by magnetostriction coefficients, which are material parameters that describe the strain dependence of the magnetization tensor. A comparison of the independently measured rheological and magnetic properties allow for the determination of the magnetostriction coefficients.
Direct Numerical Simulation of the Turbulent Ekman Layer: Turbulent Energy Budgets

Results from a direct numerical simulation of the Ekman layer at a Reynolds number of 400 were analyzed to compute energy spectra and energy budgets for this flow. Energy budgets showed that the majority of the turbulent kinetic energy in the flow is produced by the coupling between the streamwise primary Reynolds shear stress and the streamwise velocity gradient. It was also found that the coupling of the vertical velocity variance with the spanwise directions allows transfer of kinetic energy by means of the return-to-isotropy pressure strain terms due to the ‘splatting effect’.
Signatures of Stellar Reionization of the Universe

The high ionization level and nonzero metallicity (~1% Z☉) of the intergalactic gas at redshifts z 5 implies that nonlinear structure had started to form in the universe at earlier times than we currently probe. In cold dark matter (CDM) cosmologies, the first generation of baryonic objects emerges at redshifts z ~ 10-50. Here we examine the observable consequences of the possibility that an early generation of stars reionized the universe and resulted in the observed metallicity of the Lyα forest. Forthcoming microwave anisotropy experiments will be sensitive to the damping of anisotropies caused by scattering off free electrons from the reionization epoch. For a large range of CDM models with a Scalo stellar mass function, we find that reionization occurs at a redshift z 10 and damps the amplitude of anisotropies on angular scales 10° by a detectable amount, ~10%-25%. However, reionization is substantially delayed if the initial stellar mass function transformed most of the baryons into low-mass stars. In this case, the mass fraction of pregalactic stars could be constrained from the statistics of microlensing events in galactic halos or along lines of sight to quasars. Deep infrared imaging with future space telescopes (such as the Space Infrared Telescope Facility or the Next Generation Space Telescope) will be able to detect bright star clusters at z 5. The cumulative bremsstrahlung emission from these star clusters yields a measurable distortion to the spectrum of the microwave background.
Semi-global exponential stabilization of linear discrete-time systems subject to input saturation via linear feedbacks

Abstract In this paper, we show that a linear discrete-time system subject to input saturation is semi-globally exponentially stabilizable via linear state and/or output feedback laws as long as the system in the absence of input saturation is stabilizable and detectable, and has all its poles located inside or on the unit circle. Furthermore, the semi-globally stabilizing feedback laws are explicitly constructed. The results presented here are parallel to our earlier results on the continuous-time counterpart (Lin and Saberi, 1993).
The Origin of Cyclic Period Changes in Close Binaries: The Case of the Algol Binary WW Cygni

Year- to decade-long cyclic orbital period changes have been observed in several classes of close binary systems, including Algol, W Ursae Majoris, and RS Canum Venaticorum systems and the cataclysmic variables. The origin of these changes is unknown, but mass loss, apsidal motion, magnetic activity, and the presence of a third body have all been proposed. In this paper, we use new CCD observations and the century-long historical record of the times of primary eclipse for WW Cygni to explore the cause of these period changes. WW Cyg is an Algol binary whose orbital period undergoes a 56 yr cyclic variation with an amplitude of ≈0.02 days. We consider and reject the hypotheses of mass transfer, mass loss, apsidal motion, and the gravitational influence of an unseen companion as the cause for these changes. A model proposed by Applegate, which invokes changes in the gravitational quadrupole moment of the convective and rotating secondary star, is the most likely explanation of this star's orbital period changes. This finding is based on an examination of WW Cyg's residual O-C curve and an analysis of the period changes seen in 66 other Algols. Variations in the gravitational quadrupole moment are also considered to be the most likely explanation for the cyclic period changes observed in several different types of binary systems.
Stagnation point nonequilibrium radiative heating and the influence of energy exchange models

A nonequilibrium radiative heating prediction method has been used to evaluate several energy exchange models used in nonequilibrium computational fluid dynamics methods. The radiative heating measurements from the FIRE II flight experiment supply an experimental benchmark against which different formulations for these exchange models can be judged. The models which predict the lowest radiative heating are found to give the best agreement with the flight data. Examination of the spectral distribution of radiation indicates that despite close agreement of the total radiation, many of the models examined predict excessive molecular radiation. It is suggested that a study of the nonequilibrium chemical kinetics may lead to a correction for this problem.
Complex N-Heterocycle Synthesis via Iron-Catalyzed, Direct C–H Bond Amination

The manipulation of traditionally unreactive functional groups is of paramount importance in modern chemical synthesis. We have developed an iron-dipyrrinato catalyst that leverages the reactivity of iron-borne metal-ligand multiple bonds to promote the direct amination of aliphatic C-H bonds. Exposure of organic azides to the iron dipyrrinato catalyst furnishes saturated, cyclic amine products (N-heterocycles) bearing complex core-substitution patterns. This study highlights the development of C-H bond functionalization chemistry for the formation of saturated, cyclic amine products and should find broad application in the context of both pharmaceuticals and natural product synthesis.
Online ads in familiar and unfamiliar sites: effects on perceived website quality and intention to reuse

Electronic commerce is an integral part of most businesses today. The perceived quality of the website and whether users intend to reuse the site are of primary concern to online businesses. There are various factors that influence customers' intentions to reuse a site. In this paper, we investigate two of these factors: whether the site is familiar to the user and whether there are online advertisements on the website. The results indicate that familiarity and online ads do have an impact on quality and reuse, although it is not entirely as expected.
Menarche in Pediatric Patients with Crohn's Disease

The timing of menarche in Crohn’s disease (CD) is poorly described. Our objectives were to study age at menarche onset in CD, and factors associated with this. We compared the age at menarche of 34 CD patients with that for 545 controls, using data in the National Health and Nutrition Examination Survey (NHANES). Mean chronological age (CA) of CD patients (15.6 years) did not differ from that of the NHANES cohort (15.7 years; P = 0.91). The median CA at menarche (13.9 years) in CD was older than in the NHANES sample (12.0 years) (P < 0.00005). In CD patients, the cumulative incidence of menarche was 10 % at CA 12 years, 51 % at CA 14 years, and 100 % at CA 16 years. Sixty-eight percent reached menarche by bone age (BA) 13.5 years and 100 % by BA greater than 14.0 years. Menarche occurred earliest in South Asians, followed by East Asians, and then Caucasians (P = 0.02). CA at menarche is delayed in CD compared with the NHANES cohort. BA at menarche in CD is similar to BA at menarche reported for healthy children. CA at menarche in CD differs by race. If menarche has not occurred by BA greater than 14.0 years, endocrinology referral should be considered.
Luminance-induced shift in the apparent direction of gaze

Changing the luminance of one side of the sclera induces an apparent shift of the perceived direction of gaze toward the darker side of the sclera. This luminance-induced gaze shift was measured in photographic and schematic images of eyes. The effect was substantial: a moderate darkening of one side of the sclera induced an apparent shift of 8 to 10 deg of gaze; the maximum darkening induced a shift of 15 deg of gaze or more. The effect of scleral darkening was also compared to the gaze shift induced by an actual shift of the iris. The effects of the two cues were measured independently and in combination. When pitted against each other, their effects could be nulled, demonstrating that they act on a common level. Predictions of the relative strengths of the luminance and iris shift cues were developed for two simple luminance-based mechanisms: flux ratio and luminance centroid. The data showed the luminance cue was less effective than the models predicted in determining gaze direction. As an alternative...
Emerging Adults with Type 1 Diabetes during the First Year Post-High School: Perceptions of Parental Behaviors

Among 182 emerging adults with type 1 diabetes (93% White and 57% female), changes during the year post-high school were examined in perceptions of diabetes-specific conflict with parents, parent-youth shared responsibility, parental tangible aid, and parental autonomy support, as well as the moderating effects of living situation, gender, years with diabetes, and glycemic control. A linear mixed effects model, controlling for baseline values, tested the changes in and relationships among these variables over time. Changes over time in parent-youth conflict were moderated by living independently of parents; autonomy support and shared responsibility were moderated by years with diabetes; and tangible aid was moderated by glycemic control. Future longitudinal research needs to examine whether changes in parental behaviors lead to positive or negative diabetes outcomes among these emerging adults with diabetes.
Edgeworth Binomial Trees

This paper develops a simple technique for valuing European and American derivatives with underlying asset risk-neutral returns that depart from lognormal in terms of prespecified non-zero skewness and greater-than-three kurtosis. Instead of specifying the entire risk-neutral distribution by the riskless return and volatility (as in the Black-Scholes case), this distribution is specified by its third and fourth central moments as well.
On the Chandra X-Ray Sources in the Galactic Center

Recent deep Chandra surveys of the Galactic center region have revealed the existence of a faint, hard X-ray source population. While the nature of this population is unknown, it is likely that several types of stellar objects contribute. For sources involving binary systems, accreting white dwarfs and accreting neutron stars with main-sequence companions have been proposed. Among the accreting neutron star systems, previous studies have focused on stellar wind-fed sources. In this paper, we point out that binary systems in which mass transfer occurs via Roche lobe overflow (RLOF) can also contribute to this X-ray source population. A binary population synthesis study of the Galactic center region has been carried out, and it is found that evolutionary channels for neutron star formation involving the accretion-induced collapse of a massive ONeMg white dwarf, in addition to the core collapse of massive stars, can contribute to this population. The RLOF systems would appear as transients with quiescent luminosities, above 2 keV, in the range from 1031 to 1032 ergs s-1. The results reveal that RLOF systems primarily contribute to the faint X-ray source population in the Muno et al. survey and that wind-fed systems can contribute to the less sensitive Wang et al. survey. However, our results suggest that accreting neutron star systems are not likely to be the major contributor to the faint X-ray source population in the Galactic center.
Liouville models of black hole evaporation

Abstract A renormalizable two-dimensional quantum field theory, containing a metric, a dilaton and N massless scalar matter fields, has been proposed as a model for black hole evaporation reflecting the conformal anomaly. Previous work on this model has been done in the large- N (weak coupling) approximation and clear evidence for Hawking radiation and its back-reaction on the metric has been seen. There are, however, quantum consistency questions since the original model was only designed to be a c = 26 conformal field theory in the weak coupling limit. In this paper we construct new theories, differing from the old only in the dilaton dependence of the cosmological constant and reducing to it in the weak coupling limit. They are exact c = 26 conformal field theories and presumably consistent frameworks for discussing this problem. We also study the new theories with a change in the Polyakov action proposed by Strominger with a view to eliminating unphysical ghost Hawking radiation. The classical equations of motion of the new theories are explicitly soluble, thus permitting an exact analysis of both static solutions and dynamic scenarios. While the static solutions are, by and large, physically reasonable, the dynamical solutions include puzzling examples where wrong-sign Hawking radiation is stimulated by allowing matter to fall into a static solution. We indicate how the latter problem may be resolved in the full quantum theory.
A Quaternary geomagnetic instability time scale

Abstract Reversals and excursions of Earth's geomagnetic field create marker horizons that are readily detected in sedimentary and volcanic rocks worldwide. An accurate and precise chronology of these geomagnetic field instabilities is fundamental to understanding several aspects of Quaternary climate, dynamo processes, and surface processes. For example, stratigraphic correlation between marine sediment and polar ice records of climate change across the cryospheres benefits from a highly resolved record of reversals and excursions. The temporal patterns of dynamo behavior may reflect physical interactions between the molten outer core and the solid inner core or lowermost mantle. These interactions may control reversal frequency and shape the weak magnetic fields that arise during successive dynamo instabilities. Moreover, weakening of the axial dipole during reversals and excursions enhances the production of cosmogenic isotopes that are used in sediment and ice core stratigraphy and surface exposure dating. The Geomagnetic Instability Time Scale (GITS) is based on the direct dating of transitional polarity states in lava flows using the 40Ar/39Ar method, in parallel with astrochronologic age models of marine sediments in which oxygen isotope and magnetic records have been obtained. A review of data from Quaternary lava flows and sediments gives rise to a GITS that comprises 10 polarity reversals and 27 excursions that occurred during the past 2.6 million years. Nine of the ten reversals bounding chrons and subchrons are associated with 40Ar/39Ar ages of transitionally-magnetized lava flows. The tenth, the Gauss-Matuyama chron boundary, is tightly bracketed by 40Ar/39Ar dated ash deposits. Of the 27 well-documented geomagnetic field instabilities manifest as short-lived excursions, 14 occurred during the Matuyama chron and 13 during the Brunhes chron. Nineteen excursions have been dated directly using the 40Ar/39Ar method on transitionally-magnetized volcanic rocks and these form the backbone of the GITS. Excursions are clearly not the rare phenomena once thought. Rather, during the Quaternary period, they occur nearly three times as often as full polarity reversals.
Constructing an interval of Minkowski space from a causal set

A criticism sometimes made of the causal set quantum gravity program is that there is no practical scheme for identifying manifoldlike causal sets and finding embeddings of them into manifolds. A computational method for constructing an approximate embedding of a small manifoldlike causal set into Minkowski space (or any spacetime that is approximately flat at short scales) is given, and tested in the two-dimensional case. This method can also be used to determine how manifoldlike a causal set is, and conversely to define scales of manifoldlikeness.
Viral membrane fusion

Membrane fusion is an essential step when enveloped viruses enter cells. Lipid bilayer fusion requires catalysis to overcome a high kinetic barrier; viral fusion proteins are the agents that fulfill this catalytic function. Despite a variety of molecular architectures, these proteins facilitate fusion by essentially the same generic mechanism. Stimulated by a signal associated with arrival at the cell to be infected (e.g., receptor or co-receptor binding, proton binding in an endosome), they undergo a series of conformational changes. A hydrophobic segment (a “fusion loop” or “fusion peptide”) engages the target-cell membrane and collapse of the bridging intermediate thus formed draws the two membranes (virus and cell) together. We know of three structural classes for viral fusion proteins. Structures for both pre- and postfusion conformations of illustrate the beginning and end points of a process that can be probed by single-virion measurements of fusion kinetics.
Brain areas specific for attentional load in a motion tracking task

Although visual attention is known to modulate brain activity in the posterior parietal, prefrontal, and visual sensory areas, the unique roles of these areas in the control of attentional resources have remained unclear. Here, we report a dissociation in the response profiles of these areas. In a parametric functional magnetic resonance imaging (fMRI) study, subjects performed a covert motion-tracking task, in which we manipulated "attentional load" by varying the number of tracked balls. While strong effects of attention - independent of attentional load - were wide-spread, robust linear increases of brain activity with number of balls tracked were seen primarily in the posterior parietal areas, including the intraparietal sulcus (IPS) and superior parietal lobule (SPL). Thus, variations in attentional load revealed different response profiles in sensory areas as compared to control areas. Our results suggest a general role for posterior parietal areas in the deployment of visual of attentional resources.
Wave-Rotor-Enhanced Gas Turbine Engines

The benefits of wave rotor topping in small (300- to 500-kW [400- to 700-hp] class) and intermediate (2000- to 3000-kW [3000- to 4000-hp] class) turboshaft engines, and large (350- to 450-kN [80,000- to 100,000-lb f ] class) high-bypass-ratio turbofan engines are evaluated. Wave rotor performance levels are calculated using a one-dimensional design/analysis code. Baseline and wave-rotor-enhanced engine performance levels are obtained from a cycle deck in which the wave rotor is represented as a burner with pressure gain. Wave rotor topping is shown to enhance the specific fuel consumption and specific power of small- and intermediate-sized turboshaft engines significantly. The specific fuel consumption of the wave-rotor-enhanced large turbofan engine can be reduced while it operates at a significantly reduced turbine inlet temperature. The wave-rotor-enhanced engine is shown to behave off-design like a conventional engine. Discussion concerning the impact of the wave rotor/gas turbine engine integration identifies technical challenges.
Minimally invasive lateral canthopexy (MILC)

Many techniques have been described for lateral canthopexy. Here, we describe a technical modification of lateral canthopexy that involves percutaneous placement of a canthopexy suture through the confluence of the lateral superior and inferior grey lines or lateral canthal angle. A total of 52 canthopexies in 26 patients have been performed with excellent results and few complications. Our lateral canthopexy modification is a minimally invasive technique that is simple to perform, with absolute assurance of capturing the lateral canthal tendon.
Realistic Portfolio Allocation Decision-Making For The Small U.S. Retail Investor

This study introduces new domestic mixed-asset and international equity securities that allow for exact portfolio replication even by small U.S. retail investors. Using these new series, various return characteristics are examined. Finally, three sets of mean-variance analyses are conducted: a domestic equity sector-only portfolio, a domestic mixed-asset portfolio, and an international mixed-asset portfolio. Real estate warrants inclusion to varying degrees in all three portfolios. International equity inclusion was also demonstrated.
SYNTHESIS OF STEREOREGULAR HEAD,TAIL HYDROXYLATED NYLONS DERIVED FROM D-GLUCOSE

A simple procedure for the preparation of stereoregular polyhydroxypolyamides, i.e., head,tail hydroxylated nylons, derived from d-glucaric acid and alkylenediamines is described. Sodium d-glucarate 6,3-lactone was made in two steps from monopotassium d-glucarate by way of d-glucaro-6,3-lactone. Methanol insoluble salt of sodium 6-[N-(aminoalkyl)]-d-glucaramide monomer precursors were conveniently prepared by refluxing methanol solutions of even-numbered C2 to C12 aliphatic diamines with insoluble sodium d-glucarate-6,3-lactone. Each of the resulting salts was esterified/lactonized at the C-1 carboxylate terminus with HCl/methanol, and the products were made basic to give the corresponding free base amino acid ester/lactone mixture. The latter spontaneously underwent self-polymerization to give the target polyamides. An important feature of this general procedure for stereoregular polyamides from chiral d-glucaric acid is that it does not require any carbohydrate hydroxyl group protection/deprotection steps.
A formal synthesis of althiomycin

Abstract A formal synthesis of the antibiotic althiomycin has been completed preliminary to studies of the interaction of this compound with prokaryotic ribosomes.
Control implications of worker identification with firm sales success

Abstract There has been increasing interest in firms in which workers strongly identify with their firm’s success. It would seem apparent that such identification by workers should be considered as an integral element of the firm’s control systems. However, much of the literature on the myriad forms of firm culturehas focussed on its symbolic and psychological characteristics as opposed to its economic consequences. As a result many economists, and the managers who design control systems, have chosen to concentrate on such ‘hard’ controls as pay-for-performance and not on how worker identification with the firm can alleviate control problems. In this paper we use analytic models to study the control implications of high commitment human resource systems where workers identify with the success of their firm. We show that such identification can help alleviate control problems by encouraging information sharing, even when that is at the expense of worker slack.
Tricyclic heterocycles with bifunctional silicon centers

Abstract Condensation of the diorganometallic reagents (o-MC6H4)2 X (M  Li, MgCl) with HSiCl3 followed by reduction with LiAlH4 provides dibenzosilacycles, I (a, X  -; b, X NMe; c, X  CH2; d, X  CH2CH2) with two exocyclic H-substituents, . Conditions for the stepwise conversion of I to mixed bifunctional systems, (II, X  Cl, Br; III, X  OR), and bifunctional derivatives, (IV, X  Cl; V, X  OR) were determined. Controlled halogenation of I to II was accomplished with one molar equivalent of SO2Cl2 or NBS although CCl4 in the presence of ClRh(PPh3)3 or PdCl2 results in slow monochlorination. The reaction of I with excess SOCl2 or SO2Cl2 converts I to III but the latter is faster and provides fewer side reactions. Conversion of I to IV with excess alcohols occurs in high yield with ClRh(PPh3)3 but in low yield with H2PtCl6. Controlled alcoholysis of I to III could not be achieved except with tBuOH. The dichlorides, IV, are methylated in high yield to VII, . Reaction of Ib with ClRh(PPh3)3 results in elimination of H2 and formation of disilanes as indicated by trapping reactions with alcohols (formation of Vb).
GHz optomechanical resonators with high mechanical Q factor in air

We demonstrate wheel-shaped silicon optomechanical resonators for resonant operation in ambient air. The high finesse of optical whispering gallery modes (loaded optical Q factor above 500,000) allows for efficient transduction of the wheel resonator’s mechanical radial contour modes of frequency up to 1.35 GHz with high mechanical Q factor around 4,000 in air.
THE EXTENDED X-RAY NEBULA OF PSR J1420-6048

The vicinity of the unidentified EGRET source 3EG J1420-6038 has undergone extensive study in the search for counterparts, revealing the energetic young pulsar PSR J1420-6048 and its surrounding wind nebula as a likely candidate for at least part of the emission from this bright and extended gamma-ray source. We report on new Suzaku observations of PSR J1420-6048, along with analysis of archival XMM Newton data. The low background of Suzaku permits mapping of the extended X-ray nebula, indicating a tail stretching {approx} 8 minutes north of the pulsar. The X-ray data, along with archival radio and VHE data, hint at a pulsar birthsite to the North, and yield insights into its evolution and the properties of the ambient medium. We further explore such properties by modeling the spectral energy distribution (SED) of the extended nebula.
Quasicrystals from cuts in six dimensions

Abstract The principles for the six-dimensional crystallographic description of icosahedral crystals are briefly reviewed. The atomic arrangements are defined by three-dimensional “atomic surfaces”. In general, the crystals are not “tilings” formed by stacking a small number of basic building blocks. Recently, Gratias, Cahn, and Moser have determined the atomic surfaces in AlMnSi quasicrystals by analyzing x-ray and neutron scattering experiments.
Fiscal Stimulus in a Monetary Union: Evidence from U.S. Regions

We use rich historical data on military procurement to estimate the effects of government spending. We exploit regional variation in military buildups to estimate an “open economy relative multiplier” of approximately 1.5. We develop a framework for interpreting this estimate and relating it to estimates of the standard closed economy aggregate multiplier. The latter is highly sensitive to how strongly aggregate monetary and tax policy “leans against the wind.” Our open economy relative multiplier “differences out” these effects because monetary and tax policies are uniform across the nation. Our evidence indicates that demand shocks can have large effects on output. (JEL E12, E32, E62, F33, H56, H57, R12)
Theory of electromagnetic waves on auroral field lines.

Intense bursts of electromagnetic radiation generated in auroral regions during substorms radiate as much as one percent of the precipitated electron energy. The generation mechanism for the intense bursts of radio noise is apparently associated with the auroral electron beam. Some processes suggested for direct generation of electromagnetic noise by the auroral electron beam are briefly reviewed but it is suggested that the electromagnetic noise bursts are created indirectly due to radiation from strong electrostatic turbulence generated by the auroral electron beam. Due to refraction of ray paths out of the spatially limited auroral electron beam, beams below a certain intensity generate low levels of electrostatic noise as commonly observed by polar orbiting satellites. However, above a certain level, the electrostatic noise generated by the beam becomes intense and forms ‘solitons’ (large ion density cavities) or ‘spiky turbulence.’ Soliton turbulence can radiate efficiently enough to account for the observed levels of electromagnetic radiation.
Interannual to Decadal Predictability of Tropical and North Pacific Sea Surface Temperatures

Abstract A multivariate empirical model is used to show that predictability of the dominant patterns of tropical and North Pacific oceanic variability, El Nino–Southern Oscillation (ENSO), and the Pacific decadal oscillation (PDO), is mostly limited to little more than a year, despite the presence of spectral peaks on decadal time scales. The model used is a linear inverse model (LIM) derived from the observed simultaneous and 1-yr lag correlation statistics of July–June-averaged SST from the Hadley Centre Global Sea Ice and Sea Surface Temperature (HadISST) dataset for the years 1900–2002. The model accurately reproduces the power spectra of the data, including interannual and interdecadal spectral peaks that are significant relative to univariate red noise. Eigenanalysis of the linear dynamical operator yields propagating eigenmodes that correspond to these peaks but have very short decay times and, thus, limited predictability. Longer-term predictability does exist, however, due to two stationary eigen...
Opportunities for Commercial Hemp Production

Hemp production has been nonexistent in the United States since the 1950s. However, low prices for traditional crops have peeked interest in commercial hemp production. The current literature on hemp suggests that it may compete on the margin with traditional crops, but is not likely to generate sizeable profits. Hemp appears slightly more profitable than traditional row crops, but less profitable than other specialty crops. An important constraint to a viable commercial hemp industry is the current state of harvesting and processing technologies, which are quite labor intensive, and result in relatively high per unit costs.