cssi/SciSciGPT-SciSciNet huggingface dataset:
Pyroglutamylated amyloid-β peptide reverses cross β-sheets by a prion-like mechanism.

The amyloid hypothesis causatively relates the fibrillar deposits of amyloid β peptide (Aβ) to Alzheimer’s disease (AD). More recent data, however, identify the soluble oligomers as the major cytotoxic entities. Pyroglutamylated Aβ (pE-Aβ) is present in AD brains and exerts augmented neurotoxicity, which is believed to result from its higher β-sheet propensity and faster fibrillization. While this concept is based on a set of experimental results, others have reported similar β-sheet contents in unmodified and pyroglutamylated Aβ, and slower aggregation of pE-Aβ as compared to unmodified Aβ, leaving the issue unresolved. Here, we assess the structural differences between Aβ and pE-Aβ peptides that may underlie their distinct cytotoxicities. Transmission electron microscopy identifies a larger number of prefibrillar aggregates of pE-Aβ at early stages of aggregation and suggests that pE-Aβ affects the fibrillogenesis even at low molar fractions. Circular dichroism and FTIR data indicate that while the unmodified Aβ readily forms β-sheet fibrils in aqueous media, pE-Aβ displays increased α-helical and decreased β-sheet propensity. Moreover, isotope-edited FTIR spectroscopy shows that pE-Aβ reverses β-sheet formation and hence fibrillogenesis of the unmodified Aβ peptide via a prion-like mechanism. These data provide a novel structural mechanism for pE-Aβ hypertoxicity; pE-Aβ undergoes faster formation of prefibrillar aggregates due to its increased hydrophobicity, thus shifting the initial stages of fibrillogenesis toward smaller, hypertoxic oligomers of partial α-helical structure.
A dynamic general equilibrium analysis of the political economy of public education

The primary objective of this paper is to highlight the distinct roles of altruism and of self-interest in the political determination of a public education policy. I assess the relative importance of three factors in the determination of the equilibrium level of this policy: altruism, the impact of public funding of education on social security benefits, and its impact on factor prices. I then focus on the impact of implementing a social security system on the equilibrium levels of education funding and on welfare. I find that although in the benchmark economy, the presence of social security might generate support for public funding of education, its overall effect on the well-being of individuals is negative for any level of social security taxation.
Seismic Detection of Fractures From Injection: A Field Example

Detection of fractures using geophysical methods has proven elusive. A significant amount of theory has been developed, however, convincing applications of the theory to observed data have been lacking. In this paper we show a clear example of seismic amplitude changes due to controlled fracturing from injection at the Alpine field in Alaska. We use the ability of time-lapse seismic data to remove the background medium so that seismic amplitude changes due to the creation of open fluid (gas or liquid) filled fracture systems are clearly exposed around injectors.
An Integrated Perspective on Ph.D. Programs in the Economics Department: A Discussion

Like the subjects that we study, scholarly disciplines are continuously evolving and economics is no exception. These changes are reflected in our research and professional journals, but our curricula especially at the Ph.D. level lag behind. An important challenge facing economics and agricultural economics is how we can adapt our research and personnel to the current and future demand for our products. As the structure of agriculture and the general economy changes, so do the demands for our products. For example, the demands for traditional agricultural economists are being replaced by demands for resource, food, and agribusiness economists. At the same time, constrained university budgets and the declining numbers of high-quality graduate students are forcing the adoption of new efficiency measures and the integration (i.e., merging or joining) of programs. In many cases, the alternative facing departments is program elimination. Because of such challenges at Virginia Tech and Washington State, this session is considering some options to facilitate the change. The discussion comments will focus on three
Electron-electron interactions in fast neutral-neutral collisions

Abstract Differential electron emission is studied for 50–500 keV H + and H atom impact on helium. Using the first Born formulation, it is shown that projectile electron-target electron interactions are expected to dominate the differential cross sections for low energy target electron emission induced by fast neutral projectile impact on any target. Measurements of the 15° electron emission were made in order to investigate this prediction. For low impact energies, a constant ratio between the hydrogen atom and proton impact cross sections was found for emitted electron velocities less than half the projectile velocity, V P . But as the collision energy increased, for electron velocities less than 0.25 V P , the cross section ratio increased as the emitted electron velocity decreased. This is interpreted as a signature of projectile electron-target electron interactions becoming dominant for distant collisions between neutral particles.
The dynamic, size-dependent properties of [5]–[12]cycloparaphenylenes

[n]Cycloparaphenylenes (or “carbon nanohoops”) are cyclic fragments of carbon nanotubes that consist of n para linked benzene rings. These strained, all sp2 hybridized macrocycles, have size-dependent optical and electronic properties that are the most dynamic at the smallest size regime where n = 5–12. This review highlights the unique physical phenomena surrounding this class of polycyclic aromatic hydrocarbons, specifically emphasizing the novel structural, optical, and electronic properties of [5]–[12]CPPs.
Capital deepening and the rise of the factory: the American experience during the nineteenth century

Between 1850 and 1880, capital per worker in United States manufacturing increased on average by at least 75 per cent, even after taking account of declining capital goods prices. During this same period, production shifted from small, labour-intensive artisan shops to large capital-intensive factories. Similar changes have occurred in many other countries at the same stage of industrialization. Establishment-level data from the federal censuses of manufacturing, however, reveal that the shift in production in the United States accounts for a modest amount of the increased capital per worker. There, at least, capital deepening seems to have occurred in almost all firms everywhere.
Preparation of the Reagent o-Nitrobenzenesulfonylhydrazide.

o-Nitrobenzenesulfonylhydrazide (NBSH) has been shown to be a valuable reagent for the synthesis of allenes from propargylic alcohols, for the reductive transposition of allylic alcohols, and, most recently, for the deoxygenation of unhindered alcohols. Each of these transformations proceeds by Mitsunobu displacement of an alcohol with NBSH followed by in situ elimination of o-nitrobenzenesulfinic acid to form a monoalkyl diazene intermediate. The mild reaction conditions (neutral pH, reaction temperatures ≤23 °C) are especially attractive for substrates containing sensitive functional groups. The success of this methodology relies critically upon the purity of the NBSH reagent employed in the reaction. A simple and practical procedure for the preparation of NBSH of high purity and guidelines for the handling and storage of the reagent are provided in this note.
The Matrix Element Method at Next-to-Leading Order.

This paper presents an extension of the matrix element method to next-to- leading order in perturbation theory, for electro-weak final states. To accomplish this we have developed a method to calculate next-to-leading order weights on an event-by-event basis. This allows for the definition of next-to-leading order likelihoods in exactly the same fashion as at leading order, thus extending the matrix element method to next-to-leading order. A welcome by-product of the method is the straightforward and efficient generation of unweighted next-to-leading order events. As examples of the application of our next-to- leading order matrix element method we consider the measurement of the mass of the Z boson and also the search for the Higgs boson in the four lepton channel.
Speculation and hedging in the currency futures markets: Are they informative to the spot exchange rates

This study presents an empirical analysis investigating the relationship between the futures trading activities of speculators and hedgers and the potential movements of major spot exchange rates. A set of trader position measures are employed as regression predictors, including the level and change of net positions, an investor sentiment index, extremely bullish/bearish sentiments, and the peak/trough indicators. We find that the peaks and troughs of net positions are generally useful predictors to the evolution of spot exchange rates, but other trader position measures are less correlated with future market movements. In addition, speculative position measures usually forecast price-continuations in spot rates while hedging position measures forecast price-reversals in these markets. © 2011 Wiley Periodicals, Inc. Jrl Fut Mark
One Voice, But Whose Voice? Exploring What Drives Trade Association Activity

Trade associations operate under the premise of advancing the shared interests of their member firms. How well do they fulfill this role? In this paper, I measure the activity of 148 major industry trade associations over time and relate this activity to the performance of the relevant industries and dominant firms within them. Findings suggest that trade association spending increases when the profitability of the four largest firms in an industry decreases but spending is unrelated to the profitability of the industry overall. This implies that large firms exert control over trade association agendas and may use these communal organizations to advance their own interests rather than the shared interests of the entire industry. Moreover, it points to the need for further development of the currently anemic management literature on the activities of trade associations.
Thermal evolution of the earth - Effects of volatile exchange between atmosphere and interior

A parameterized model of mantle convection that includes the effects of volatile exchange between the mantle and the surface reservoir and the softening of the mantle by the dissolved volatiles is used to study the thermal history of the Earth. It is assumed that the activation energy for temperature-dependent solid-state creep is a linear function of weight percent of volatiles. The mantle degassing rate is taken to be directly proportional to the rate of seafloor spreading which depends on the mantle heat flow. The rate of regassing also varies with the seafloor spreading rate, but it depends on other factors as well, including the mass of the atmosphere-hydrosphere system and the efficiency of volatile recycling through island arc volcanoes. Because the degassing/regassing rates are a function of convective vigor which is regulated by mantle volatile content (through the volatile dependence of viscosity), the devolatilization/revolatilization of the mantle is self-consistently calculated. Model results indicate that mantle degassing and regassing rates quickly equifibrate during an early stage of rapid Earth cooling and adjust to regulate a more gradual cooling of the Earth over most of geologic time. These adjustments occur in the first several hundred million years of Earth's history. Most of the net volatile release from the mantle (or in some cases, net volatile absorption into the mantle) occurs early, in accord with isotopic evidence for rapid formation of the atmosphere. The net mass of volatiles released from the mantle is easily comparable to that of Earth's oceans. When mantle viscosity depends on both volatile content and temperature, changes in volatile content are compensated by changes in temperature so that the mantle evolves with the viscosity and convective vigor required to transfer its internally generated heat. Thus, the mantle is hotter (colder) as a consequence of degassing (regassing) compared to a mantle with volatile-independent rheology. The ratio of internal heat generation to total heat flow (the Urey ratio) is regulated by the temperature dependence of viscosity; models with high initial Urey ratios build up high temperatures very rapidly, thereby enhancing heat flow and reducing the Urey ratio. Early volatile loss from the mantle leads to a more rapid buildup of high temperature; thus, the "corrective" heat flow occurs even faster. Due to these feedback effects, the present value of the Urey ratio cannot exceed unity.
An Analytical Study of the Optimized Performance of an Impingement Heat Sink

The results of a study of a new and unique high performance air-cooled impingement heat sink are presented. An extensive numerical investigation of the heat sink performance is conducted and is verified by experimental data. The study is relevant to cooling of high power chips and modules in air-cooled environments and applies to workstations or mainframes. In the study, a rectangular jet impinges on a set of parallel fins and then turns into cross-flow. The effects of the fin thickness and gap nozzle width and fin shape on the heat transfer and pressure drop are investigated. It is found that pressure drop is reduced by cutting the fins in the central impingement zone without sacrificing the heat transfer due to a reduction in the extent of the stagnant zone. A combination of fin thicknesses of the order of 0.5 mm and channel-gaps of 0.8 mm with appropriate central cut-out yielded heat transfer coefficients over 1500 W/m2 K at a pressure drop of less than 100 N/m2 , as is typically available in high-end workstations. A detailed study of flow-through heat sinks, subject to the same constraints as the impingement heat sink showed that the flow-through heat sink could not achieve the high heat transfer coefficients at a low pressure drop.Copyright © 2003 by ASME
Exact results for the entanglement entropy and the energy radiated by a quark

We consider a spherical region with a heavy quark in the middle. We compute the extra entanglement entropy due to the presence of a heavy quark both in $ \mathcal{N} $ = 4 Super Yang Mills and in the $ \mathcal{N} $ = 6 Chern-Simons matter theory (ABJM). This is done by relating the computation to the expectation value of a circular Wilson loop and a stress tensor insertion. We also give an exact expression for the Bremsstrahlung function that determines the energy radiated by a quark in the ABJM theory.
Resource Defense and Alternative Mating Tactics in the Banksia Bee, Hylaeus alcyoneus (Erichson)

Some males of the Australian colletid bee Hylaeus alcyoneus defend single flowering spikes of various species of Banksia, selecting spikes in the maturational state most attractive to foraging females. Other males do not engage in food resource defense but instead nonaggressively patrol a circuit that takes them to many spikes, some occupied, others not held by territorial males. When territory owners are experimentally removed, replacement males quickly claim the vacated spikes. Some of these males have been patrolling previously, showing that patrolling and territoriality are alternative tactics in a conditional strategy. Territorial males are larger on average than patrolling males, replacement territory holders, and females. Male territoriality at flowers appears in several other Hylaeus, and in these and other bees, resource defense tactics are often associated with specialized foraging requirements of females and a patchily distributed resource.
Dilaton black holes with electric charge.

New static spherically symmetric solutions of the Einstein-Maxwell gravity with the dilaton field are found. The solutions correspond to black holes and naked singularities. In addition to mass and electric charge these solutions are labeled by a new parameter, the dilaton charge of the black hole. Depending on the values of electric and dilaton charges there are different types of solutions. The solutions exhibit a new type of a symmetry. Namely one solution transforms into another when the mass and the dilaton charge are interchanged. We also found that there is a finite interval of values of electric charge for which no black hole can exist. This gap separates two different types of solutions. Inside the gap the solution can exist only if the dilaton charge is exactly equal to the negative of the mass. The behavior of the solution in the extremal regime is also analyzed.
The N-Substitution of Aliphatic Primary Amines via 1-[(Alkylamino)methyl]benzotriazoles: Preparation of Secondary Amines

A new method has been developed for the selective conversion of primary aliphatic amines into unsymmetrical secondary amines by Grignard reaction of 1-[(alkylamino)methyl]-benzotriazoles 1. This method employs simple procedure and mild conditions, and is specific in that only monoalkylation of the primary amines results.
Systematic Biases in Galaxy Luminosity Functions

Both the detection of galaxies and the derivation of the luminosity function depend upon isophotal magnitudes, implicitly in the first case and explicitly in the latter. However, unlike perfect point sources, the fraction of a galaxy's light contained within the limiting isophote is a function of redshift, owing to the combined effects of the point-spread function and cosmological dimming. This redshift variation in the measured isophotal luminosity can strongly affect the derived luminosity function. Using simulations that include the effects of seeing upon both disk and elliptical galaxies, we explore the size of the systematic biases that can result from ignoring the redshift variation in the fraction of detected light. We show that the biases lead to underestimates in the normalization of the luminosity function, as well as changes in shape. The size of the bias depends upon redshift, and thus can mimic galaxy evolution. Surprisingly, these biases can be extremely large without affecting V/Vmax. However, these biases can be detected in the full distribution of V/Vmax and in fact may have already been detected in recent surveys. Because the systematic biases result from the redshift variation in the fraction of lost light, the biases are not significant when the fraction of lost light is always small over the entire survey volume, for all galaxy types. However, as modern galaxy surveys now reach higher redshifts, lower surface brightnesses, and smaller angular sizes, the effects of seeing and galaxy visibility are becoming increasingly important and need to be taken into account. We show that the expected biases are not necessarily eliminated when using aperture magnitudes, Faint Object Classification and Analysis System total magnitudes, or Kron magnitudes, but may be reduced significantly if Petrosian magnitudes are used. These considerations may also apply to samples of clusters selected in X-rays.
Efficient methods for computing observation impact in 4D-Var data assimilation

This paper presents a practical computational approach to quantify the effect of individual observations in estimating the state of a system. Such a methodology can be used for pruning redundant measurements and for designing future sensor networks. The mathematical approach is based on computing the sensitivity of the analyzed model states (unconstrained optimization solution) with respect to the data. The computational cost is dominated by the solution of a linear system, whose matrix is the Hessian of the cost function, and is only available in operator form. The right-hand side is the gradient of a scalar cost function that quantifies the forecast error of the numerical model. The use of adjoint models to obtain the necessary first- and second-order derivatives is discussed. We study various strategies to accelerate the computation, including matrix-free iterative solvers, preconditioners, and an in-house multigrid solver. Experiments are conducted on both a small-size shallow-water equations model and on a large-scale numerical weather prediction model, in order to illustrate the capabilities of the new methodology.
Androgen receptors detected by autoradiography in prostatic carcinoma and benign prostatic hyperplastic tissue

Androgen receptor (AR) content in prostatic tissues from patients with either cancer or benign prostatic hyperplasia (BPH) is of interest from at least two standpoints: receptors may be a feature of the pathogenesis of these conditions, and they may be important to the management and prognosis of prostatic cancer patients. For these reasons, a quantitative autoradiographic assay for AR content in prostatic tissues has been developed. Application of autoradiography to rodent tissues yielded results that were highly correlated with those from biochemical assays. Thus, the autoradiographic analyses with human tissues reported in this paper were undertaken. Average AR content in 22 prostatic carcinomas was lower than that in tissues from 14 patients with BPH; the median values of the affinity index, the quantitative estimate of receptor content, were 7.0 and 12.0, respectively. For the cancer tissues, a trend of declining receptor content with advancing stage of disease appeared but was not statistically significant. No association between receptor content and degree of tumor aggressiveness as measured by Gleason score and MD Anderson score was evident. Patient age and race were not related to receptor content in either type of tissue.
THE VALUE OF TIME AND RELIABILITY: MEASUREMENT FROM A VALUE PRICING EXPERIMENT

Abstract We measure values of time and reliability from 1998 data on actual behavior of commuters on State Route 91 in Orange County, California, where they choose between a free and a variably tolled route. For each route at each time of day and for each day of the week, the distribution of travel times across different weeks is measured using loop detector data. The best-fitting models represent travel-time by its median, and unreliability by the difference between the 90th percentile and the median. We present models of route choice both alone and combined with other choices, namely time of day, car occupancy, and installation of an electronic transponder. In our best model, containing all these choices except time of day, value of time (VOT) is $22.87 per hour, while value of reliability is $15.12 per hour for men and $31.91 for women. These values are 72%, 48%, and 101%, respectively, of the average wage rate in our sample.
Continuity of extremal elements in uniformly convex spaces

In this paper, we study the problem of finding the extremal element for a linear functional over a uniformly convex Banach space. We show that a unique extremal element exists and depends continuously on the linear functional, and vice versa. Using this, we simplify and clarify Ryabykh's proof that for any linear functional on a uniformly convex Bergman space with kernel in a certain Hardy space, the extremal function belongs to the corresponding Hardy space.
Controlled functional group presentations in dendrimers as a tool to probe the hyperbranched architecture

The layer-by-layer incorporation of monomers in the synthesis of dendrimers allows for variations in the functionalities between one layer and the next. However, incorporation of different functionalities in combination with the above would lead to the introduction of sequences in dendrimers. We review the three complementary synthetic methods we have developed for sequencing the dendrimers. We also illustrate the utility of these methodologies in identifying certain fundamental properties of dendrimers. More specifically, we have probed the intermediate layers of the dendrimers by incorporation of spectroscopic probes in precise locations within dendrimers. Similarly, we have utilized this method to identify the true architectural advantages of dendrimers as light harvesters in solar energy applications.
Solution to exchanges 10.2 puzzle: borrowing in the limit as our nerdiness goes to infinity

This is a solution to the editor's puzzle from issue 10.2 of SIGecom Exchanges [Reeves 2011]. The Puzzle asks to determine a point in time such that a lump sum payment of $S will be equivalent to a continuous stream of infinitesimal payments totaling $S, spread evenly over time. The full puzzle can be found online at: http://www.sigecom.org/exchanges/volume_10/2/puzzle.pdf.
Revisiting the Hirao Cross-coupling: Improved Synthesis of Aryl and Heteroaryl Phosphonates

The palladium-catalyzed cross-coupling of dialkylphosphite with aromatic electrophiles (Hirao coupling) was re-investigated. Some limitations in terms of palladium loadings and substrate reactivity are alleviated with the use of Pd(OAc)2 complexed to 1,1′-bis(diphenylphosphino)ferrocene (dppf) as a ligand. Various aryl and heteroaryl halides are employed to deliver both known and novel substituted phosphonates. The first examples of aryl chloride couplings are also reported.
Variability in urinary phthalate metabolite levels across pregnancy and sensitive windows of exposure for the risk of preterm birth

Abstract Background Preterm birth is a significant public health problem, affecting over 1 in 10 live births and contributing largely to infant mortality and morbidity. Everyday exposure to environmental chemicals such as phthalates could contribute to prematurity, and may be modifiable. In the present study we examine variability in phthalate exposure across gestation and identify windows of susceptibility for the relationship with preterm birth. Methods Women were recruited early in pregnancy as part of a prospective, longitudinal birth cohort at the Brigham and Women's Hospital in Boston, Massachusetts. Urine samples were collected at up to 4 time points during gestation for phthalate measurement, and birth outcomes were recorded at delivery. From this population we selected all 130 cases of preterm birth, defined as delivery before 37 weeks of completed gestation, as well as 352 random controls. Results Urinary phthalate metabolite levels were moderately variable over pregnancy, but levels measured at multiple time points were associated with increased odds of preterm birth. Adjusted odds ratios (aOR) for spontaneous preterm birth were strongest in association with phthalate metabolite concentrations measured at the beginning of the third trimester (aOR for summed di-2-ethylhexyl phthalate metabolites [∑ DEHP] = 1.33, 95% confidence interval [CI] = 1.02, 1.73). Odds ratios for placental preterm birth, defined as delivery with presentation of preeclampsia or intrauterine growth restriction, were slightly elevated in the first trimester for DEHP metabolites (aOR for ∑ DEHP = 1.33, 95% CI = 0.99, 1.78). Conclusions Pregnant women with exposure to phthalates both early and late in pregnancy are at an increased risk of delivering preterm, but mechanisms may differ based on etiology.
Synthesis of N-(2-deoxy-β-d-ribosyl) 4-thiomethylindole: A purine surrogate for incorporation into oligonucleotides.

Efficient, high-yielding syntheses of S-acetyl-N-(2-deoxy-β-d-ribosyl) 4-thiomethylindole (9) and the corresponding 5′-O-trityl-3′-O-phosphoramidite ester 11 are reported, suitable for direct incorporation into oligodeoxynucleotides by standard solid-phase synthesis techniques.
The use of anaphoric resolution for document description in information retrieval

Abstract This study investigated two hypotheses concerning the use of anaphors in information retrieval. The first hypothesis, that anaphors tend to refer to integral concepts rather than to peripheral concepts, was well supported. Two samples of documents, one in psychology and the other in computer science, were examined by subject experts who judged the centrality of phrases that were referred to anaphorically. The second hypothesis, that various term weighting schemes are affected differently by anaphoric resolution, was also well supported. It was found that schemes that incorporate document length into the calculations produce much smaller increases in term weights for terms occurring in anaphoric resolutions than those that do not consider document length. Further analysis revealed that increases in query term occurrences after resolution of anaphors do not help to discriminate between relevant and nonrelevant documents. It is concluded that although anaphoric resolution has potential for better representing the “aboutness” of a document, it may have more value in the representation of the relationships among concepts in the document, rather than in the representation of the concepts themselves.
An Adler–Becker oxidation approach to vinigrol

Abstract Detailed in this Letter is an Adler–Becker oxidation strategy towards vinigrol. The effects of substitution were shown to greatly impact successes of both the oxidative dearomatization and Diels–Alder reactions.
Lower bounds for Kazhdan-Lusztig polynomials from patterns

Kazhdan-Lusztig polynomials Px,w(q) play an important role in the study of Schubert varieties as well as the representation theory of semisimple Lie algebras. We give a lower bound for the values Px,w(1) in terms of "patterns". A pattern for an element of a Weyl group is its image under a combinatorially defined map to a subgroup generated by reflections. This generalizes the classical definition of patterns in symmetric groups. This map corresponds geometrically to restriction to the fixed point set of an action of a one-dimensional torus on the flag variety of a semisimple group G. Our lower bound comes from applying a decomposition theorem for "hyperbolic localization" [Br] to this torus action. This gives a geometric explanation for the appearance of pattern avoidance in the study of singularities of Schubert varieties.
Point-ahead limitation on reciprocity tracking

The average power received at a spacecraft from a reciprocity-tracking transmitter is shown to be the free-space diffraction-limited result times a gain-reduction factor that is due to the point-ahead requirement. For a constant-power transmitter, the gain-reduction factor is approximately equal to the appropriate spherical-wave mutual-coherence function. For a constant-average-power transmitter, an exact expression is obtained for the gain-reduction factor.
A density functional study of plutonium dioxide

The electronic and geometric structures of bulk PuO2 and its (110) surface have been studied using a periodic model within the generalized gradient approximation (GGA) of density functional theory (DFT). The sixty core electrons of the Pu atom have been represented by a relativistic effective core potential and scalar relativistic effects have been incorporated on the valence orbitals. For bulk PuO2, we predict an equilibrium lattice constant of 10.10 a.u. and a cohesive energy of 17.28 eV, in good agreement with experimental data. For the (110) surface, upon relaxation, the distance between the top layer and the next layer is found to decrease by 0.12 A, i.e. 5.3% of the corresponding interlayer distance in the bulk. The distance between the two oxygen atoms on the top layer is found to increase by 0.15 A, i.e. 5.6% of the corresponding bulk value. The small surface relaxation energy of 0.268 eV per unit cell indicates the fair stability of this surface. The effective charges on Pu and O atoms show that the chemical bonding in this system is not purely ionic. Together with the metallic feature of the density of states (DOS) on the surface, the effective charge distribution provides some basis for understanding surface reactivity and corresponding support for catalysis.
The early treatment and prognosis of epilepsy.

Summary In the last decade community and hospital-based studies of epilepsy from the onset of the disorder have revealed a much more favorable prognosis for seizure control than previously reported. Approximately three-quarters of newly diagnosed patients can enter a prolonged remission on currently available medication. The natural history of untreated epilepsy is unknown but there is some evidence of an escalating process in the early stages in patients with tonic-clonic seizures. The first two years of treatment seem to be important in determining the subsequent course of epilepsy. The longer seizures continue, the less likely they are to b: controlled. Early effective treatment may be important in preventing the evolution of chronic epilepsy. These observations have implications for the management of patients with single seizures.
Preparation of Composite Particles by Pulsed Nd‐YAG Laser Decomposition of [(CH3)2N]4Ti to TiN‐Coat TiO2, Al2O3, or Si3N4 Powders

Irradiation of Ti[N(CH,),], by the 1.064-pm line of a pulsed Nd:YAG laser in the presence of TiO,, AI,O,, or Si,N, particles has been found to form amorphous deposits on the oxide particles. The resulting materials can be processed into TiN/TiO,, TiN/AI,O,, or TiN/Si,N, composites with the TIN component on the surface of the particles. The powders have been characterized by Raman spectroscopy and X-ray powder diffraction studies. The surface analysis of the composites by X-ray photoelectron spectroscopy and highresolution electron microscopy is presented.
Investigation of scalar measurement error in diffusion and mixing processes

In variable density, multi-fluid and reacting flows, the degree of molecular mixing is a critical component of turbulent transfer and mixing models. Also, in many microflows and low Reynolds number flows, scalar diffusion length- and time-scales play a significant role in the mixing dynamics. Characterization of such molecular mixing processes requires scalar measurement devices with a small probe volume size. Spatial averaging, which occurs due to finite probe volume size, can lead to errors in resolving the density or scalar gradients between pockets of unmixed fluids. Given a probe volume size and a priori knowledge of the functional profile of the diffusion layer being measured, we obtain an estimate for the measurement error due to spatial averaging and make the corrections accordingly. An analytical model for the measure of scalar mixing is developed as a predictor for the growth of scalar gradients in a variable scalar flow. The model is applied to a buoyancy-driven mixing layer with a Prandtl number of 7. Measurements within the mixing layer have shown that initial entrainment of unmixed fluid causes a decrease in the measured amount of molecular mixing at the centerplane. Following this period of initial entrainment, the fluids within the mixing layer exhibit an increase in the degree of molecular mixing.
A Revised Parallax and Its Implications for RX J185635?3754

New astrometric analysis of four Wide Field Planetary Camera 2 images of the isolated neutron star RX J185635-3754 shows that its distance is 117 ± 12 pc, nearly double the originally published distance. We argue that the star's birthplace was in the Upper Scorpius association but that a connection with ζ Ophiuchi is now unlikely. Assuming birth in Upper Sco, the revised distance yields an age of 5 × 105 yr and a space velocity of about 185 km s-1. The radiation radius inferred from fitting the full spectral energy distribution lies between 12 and 26 km, with a best fit R∞ = 16.4 ± 0.3 km for a two-blackbody model. These radii are in the range of many equations of state, both with and without exotic matter, and remove the observational support for an extremely soft equation of state.
Eigenvalues of PT-symmetric oscillators with polynomial potentials

We study the eigenvalue problem −u''(z) − [(iz)m + Pm−1(iz)]u(z) = λu(z) with the boundary condition that u(z) decays to zero as z tends to infinity along the rays in the complex plane, where Pm−1(z) = a1zm−1 + a2zm−2 + ⋅ ⋅ ⋅ + am−1z is a polynomial and integers m ≥ 3. We provide an asymptotic expansion of the eigenvalues λn as n → +∞, and prove that for each real polynomial Pm−1, the eigenvalues are all real and positive, with only finitely many exceptions.
Selective ion acceleration in impulsive solar flares

Abstract The spectacular enrichment of 3He and the smaller enrichments of heavy ions in impulsive flares is discussed in the context of a resonant interaction with the same electromagnetic ion cyclotron waves. The observed abundances are used to delineate the coronal thermodynamic conditions, the scalings of the enhancements with the coronal parameters and the frequency range of the resonant waves.
C–H Methylation of Heteroarenes Inspired by Radical SAM Methyl Transferase

A practical C–H functionalization method for the methylation of heteroarenes is presented. Inspiration from Nature’s methylating agent, S-adenosylmethionine (SAM), allowed for the design and development of zinc bis(phenylsulfonylmethanesulfinate), or PSMS. The action of PSMS on a heteroarene generates a (phenylsulfonyl)methylated intermediate that can be easily separated from unreacted starting material. This intermediate can then be desulfonylated to the methylated product or elaborated to a deuteriomethylated product, and can divergently access medicinally important motifs. This mild, operationally simple protocol that can be conducted in open air at room temperature is compatible with sensitive functional groups for the late-stage functionalization of pharmacologically relevant substrates.
The Progenitor stars of gamma-ray bursts

Those massive stars that give rise to gamma-ray bursts (GRBs) during their deaths must be endowed with an unusually large amount of angular momentum in their inner regions, 1-2 orders of magnitude greater than the ones that make common pulsars. Yet the inclusion of mass loss and angular momentum transport by magnetic torques during the precollapse evolution is known to sap the core of the necessary rotation. Here we explore the evolution of very rapidly rotating massive stars, including stripped-down helium cores that might result from mergers or mass transfer in a binary, and single stars that rotate unusually rapidly on the main sequence. For the highest possible rotation rates (about 400 km s-1), a novel sort of evolution is encountered in which single stars mix completely on the main sequence, never becoming red giants. Such stars, essentially massive "blue stragglers," produce helium-oxygen cores that rotate unusually rapidly. Such stars might comprise roughly 1% of all stars above 10 M☉ and can, under certain circumstances, retain enough angular momentum to make GRBs. Because this possibility is very sensitive to mass loss, GRBs are much more probable in regions of low metallicity.
New organocopper reagents prepared utilizing highly reactive copper

Abstract Highly reactive copper solutions have been prepared by the lithium naphthalide reduction of copper(I) iodide/trialkylphosphine complexes. These activated copper solutions will react with organic halides under very mild conditions to form stable organocopper reagents. Significantly, the organocopper reagents can contain considerable functionalities such as ester, nitrile, chloride, epoxide, and ketone groups. These functionalized organocopper species undergo many reactions typical of other organocopper species. Intermolecular 1,4-additions, epoxide-opening reactions, and ketone formation with acid chlorides have been successfully achieved. In addition, this methodology has been applied to an intramolecular epoxide-cleavage reaction. The Influence of the connecting chain length, substitution pattern, reaction solvent, and CuI/phosphine complex upon the regioselectivity of the intramolecular cyclization is described.
Photosensitized cleavage of the dithio protecting group by visible light

Abstract Dithio derivatives of aldehydes and ketones have been deprotected under neutral conditions using visible light provided by a 120 Watt spotlight and methylene green as a sensitizer. The key step in the deprotection is apparently an electron transfer from the dithio derivative to the electronically excited visible dye. The resulting dithio radical cation undergoes fragmentation, and the corresponding aldehydes and ketones are isolated in excellent yields.
Coherent sources direction finding and polarization estimation with various compositions of spatially spread polarized antenna arrays

Abstract Various compositions of sparsely polarized antenna arrays are proposed in this paper to estimate the direction-of-arrivals (DOAs) and polarizations of multiple coherent sources. These polarized antenna arrays are composed of one of the following five sparsely spread sub-array geometries: (1) four spatially spread dipoles with three orthogonal orientations, (2) four spatially spread loops with three orthogonal orientations, (3) three spatially spread dipoles and three spatially spread loops with orthogonal orientations, (4) three collocated dipole–loop pairs with orthogonal orientations, and (5) a collocated dipole–triad and a collocated loop–triad. All the dipoles/loops/pairs/triads in each sub-array can also be sparsely spaced with the inter-antenna spacing far larger than a half-wavelength. Only one dimensional spatial-smoothing is used in the proposed algorithm to derive the two-dimensional DOAs and polarizations of multiple cross-correlated signals. From the simulation results, the sparse array composed of dipole–triads and loop–triads is recommended to construct a large aperture array, while the sparse arrays composed of only dipoles or only loops are recommended to efficiently reduce the mutual coupling across the antennas. Practical applications include distributed arrays and passive radar systems.
Space-Time Approach to Non-Relativistic Quantum Mechanics

Non-relativistic quantum mechanics is formulated here in a different way. It is, however, mathematically equivalent to the familiar formulation. In quantum mechanics the probability of an event which can happen in several different ways is the absolute square of a sum of complex contributions, one from each alternative way. The probability that a particle will be found to have a path x(t) lying somewhere within a region of space time is the square of a sum of contributions, one from each path in the region. The contribution from a single path is postulated to be an exponential whose (imaginary) phase is the classical action (in units of ℏ) for the path in question. The total contribution from all paths reaching x, t from the past is the wave function ψ(x, t). This is shown to satisfy Schroedinger's equation. The relation to matrix and operator algebra is discussed. Applications are indicated, in particular to eliminate the coordinates of the field oscillators from the equations of quantum electrodynamics.
Trees and Markov Convexity

We show that an infinite weighted tree admits a bi-Lipschitz embedding into Hilbert space if and only if it does not contain arbitrarily large complete binary trees with uniformly bounded distortion. We also introduce a new metric invariant called Markov convexity, and show how it can be used to compute the Euclidean distortion of any metric tree up to universal factors.
A novel chiral ferrocenyl phosphine ligand from sugar: applications in Rh-catalyzed asymmetric hydrogenation reactions.

A new chiral ferrocenyl diphosphine ligand 3 was synthesized from readily available d-mannitol. Rh-complex with this ligand showed high enantioselectivity and reactivity in the asymmetric hydrogenation of dehydroamino acid derivatives and itaconic acid derivatives. Up to over 99% ee and 10 000 TON were achieved with this catalytic system.
Elementary transversality in the Schubert calculus in any characteristic

We give a characteristic-free proof that general codimension-1 Schubert varieties meet transversally in a Grassmannian and in some related varieties. Thus the corresponding intersection numbers are enumerative in all characteristics. Existing transversality results do not apply to these enumerative problems, emphasizing the need for additional theoretical work on transversality. We also strengthen some results in enumerative real algebraic geometry.
Nanoscale Effects on Heterojunction Electron Gases in GaN/AlGaN Core/Shell Nanowires

The electronic properties of heterojunction electron gases formed in GaN/AlGaN core/shell nanowires with hexagonal and triangular cross sections are studied theoretically. We show that at nanoscale dimensions, the nonpolar hexagonal system exhibits degenerate quasi-one-dimensional electron gases at the hexagon corners, which transition to a core-centered electron gas at lower doping. In contrast, polar triangular core/shell nanowires show either a nondegenerate electron gas on the polar face or a single quasi-one-dimensional electron gas at the corner opposite the polar face, depending on the termination of the polar face. More generally, our results indicate that electron gases in closed nanoscale systems are qualitatively different from their bulk counterparts.
Some features of CARDIAD plots for system dominance

Recently, the CARDIAD (Complex Acceptability Region for DIAgonal Dominance) plot has been introduced and applied to the problem of designing dynamical precompensation to achieve column dominance. This paper illustrates several basic features of the method while using it to design a single, low-order dynamical compensator which achieves dominance at five operating points of a realistic two-spool turbofan digital simulation.
The Ionized Stellar Wind in Vela X-1 during Eclipse

We present a first analysis of a high-resolution X-ray spectrum of the ionized stellar wind of Vela X-1 during eclipse. The data were obtained with the High-Energy Transmission Grating Spectrometer on board the Chandra X-Ray Observatory. The spectrum is resolved into emission lines with fluxes between 0.02 and 1.04 × 10-4 photons cm-2 s-1. We identify lines from a variety of charge states, including fluorescent lines from cold material and a warm photoionized wind. We can exclude signatures from collisionally ionized plasmas. For the first time, we identify fluorescent lines from L-shell ions from lower Z elements. We also detect radiative recombination continua from a kT = 10 eV (1.2 × 105 K) photoionized optically thin gas. The fluorescent line fluxes imly the existence of optically thick and clumped matter within or outside the warm photoionized plasma.
Anaerobic treatment of army ammunition production wastewater containing perchlorate and RDX.

Abstract Perchlorate is an oxidizer that has been routinely used in solid rocket motors by the Department of Defense and National Aeronautics and Space Administration. Royal Demolition Explosive (RDX) is a major component of military high explosives and is used in a wide variety of munitions. Perchlorate bearing wastewater typically results from production of solid rocket motors, while RDX is transferred to Army industrial wastewaters during load, assemble and pack operations for new munitions, and hot water or steam washout for disposal and deactivation of old munitions (commonly referred to as demilitarization, or simply demil). Biological degradation in Anaerobic Fluidized Bed Reactors (AFBR), has been shown to be an effective method for the removal of both perchlorate and RDX in contaminated wastewater. The focus of this study was to determine the effectiveness of removal of perchlorate and RDX, individually and when co-mingled, using ethanol as an electron donor under steady state conditions. Three AFBRs were used to assess the effectiveness of this process in treating the wastewater. The performance of the bioreactors was monitored relative to perchlorate, RDX, and chemical oxygen demand removal effectiveness. The experimental results demonstrated that the biodegradation of perchlorate and RDX was more effective in bioreactors receiving the single contaminant than in the bioreactor where both contaminants were fed.