cssi/SciSciGPT-SciSciNet huggingface dataset:
An improved method for the synthesis of zirconium (CCC-N-heterocyclic carbene) pincer complexes and applications in hydroamination.

Upon heating Zr(NMe2)4, 1,3-bis(N-butyl-imidazolium)benzene diiodide and toluene analytically pure Zr pincer complex was obtained, which was found to be an intramolecular hydroamination catalyst.
Constraints On Vector Unparticle Physics From Cosmic Censorship

Vector unparticle couplings to standard model fields produce repulsive corrections to gravity. From a general relativistic perspective, this leads to an effective Reissner-Nordstrom-like metric whose “charge” is a function of the unparticle coupling constant λ, and therefore can admit naked singularities. Requiring the system to respect cosmic censorship provides a new method of constraining the value of λ. These limits are extremely loose for stellar-mass black holes, but commensurate with existing bounds for primordial black holes. In the case of theoretical low-mass black holes, the bounds on λ are much stricter than those derived from astrophysical and accelerator phenomenology. Additional constraints on the lower limit of λ are used to estimate the mass of the smallest possible black hole $M_{\mathrm {BH}}^{\mathrm{min}}$ that can be formed in the unparticle framework, as a function of the unparticle parameters ( $\Lambda_{{\mathcal{U}}},M_{{\mathcal{U}}},{d_{\mathcal{U}}},{d_{\mathit{BZ}}}$ ).
Hopf term induced by fermions

Abstract We derive an effective action for Dirac fermions coupled to O(3) non-linear σ-model (NLσM) through the Yukawa-type interaction. The nonperturbative (global) quantum anomaly of this model results in a Hopf term for the effective NLσM. We obtain this term using the “embedding” of the CP1 model into the CPM generalization of the model which makes the quantum anomaly perturbative. This perturbative anomaly is calculated by means of a gradient expansion of a fermionic determinant and is given by the Chern–Simons term for an auxiliary gauge field.
Cross sections relevant to gamma-ray astronomy: Alpha-particle-induced reactions

Gamma-ray production cross sections have been measured for the gamma-ray lines most strongly excited in the alpha-particle bombardments of /sup 20/Ne, /sup 24/Mg, /sup 27/Al, /sup 28/Si, and /sup 56/Fe for alpha-particle energies from threshold to approximately 27 MeV. Tabulations of cross sections averaged over alpha-particle energy bins of 1 MeV are provided for calculations relevant to gamma-ray line astronomy. Examples are given of astrophysical information which might be extracted from spectra acquired with gamma-ray spectrometers in space using these cross sections.
Omeka in the classroom: The challenges of teaching material culture in a digital world

An often-overlooked challenge to the field of digital humanities is the lack of interest in the discipline by young scholars. Despite being the so-called digital natives, many of my museum studies students have no desire to engage with new technology. This short paper is a snapshot of my attempt to teach digital curation and online exhibit development within the framework of my material culture seminar. It analyses 3 years of student exhibits developed using Omeka and points to new directions the project will go over the next several years. I began the research project by asking the following questions of my students: What does material culture look like on the web? How do you curate it? How does the public interact with virtual objects? What is the relationship between virtual and physical museum artifacts? However, after seeing the students struggle with basic web development, I expanded my own research questions to include: What skills do emerging professionals need and how can we integrate technical training into an academic program? For presenters and attendees at DH2011, there is no need to sing the praises of the digital world. We are the early adopters, the converted, the evangelists. But our colleagues across the humanities are not yet entirely convinced, and of more concern to me, neither are the students. As always, I enjoyed the papers at DH and was inspired by many of the fabulous projects. This paper goes in the opposite direction. I direct the museum studies track of the masters in public history at the University of South Carolina, one of the oldest public history programs in the country. It is a nationally competitive program, and our graduates have an impressive placement record: the Smithsonian; the National Park Service; federal, state, and local government. And yet, since I joined the faculty 4 years ago, I have been shocked that the students—the so-called digital natives—have little interest in the digital world as part of their professional training. They may communicate with each other using Facebook, share photos on Flickr, or post to their personal blogs, but when it comes to coursework they expect, and sometimes demand, a traditional graduate seminar where we read and discuss books. More than one student has balked at my assignments, whining, ‘I don’t need to learn how to program. I just want to be a regular historian.’ Unyielding in my persistence, I argue back that it is no longer an option. Wikis, blogs, and tweeting are everyday realities for museum professionals. At the very minimum, all curators and collections managers need to have a basic understanding of database architecture in order to structure their object databases and construct useful queries. More importantly, two decades of digitization have created new questions for curators of three-dimensional objects: What does material culture look like on the web? How do Correspondence:
Influence of the n-diffusion layer on the channel current and the breakdown voltage in 4H-SiC SIT

For a recessed gate (RG) silicon carbide (SiC) static induction transistor (SIT), an n-diffusion layer technique to maximize a maximum channel current (I/sub MAX/) and realize an efficient breakdown voltage (BV) was presented. An n-diffusion layer having a doping profile of a Gaussian distribution was formed from the source to the channel region and introduced to elevate the doping concentration of the channel region. Through the simulation of a RG SiC SIT with an n-diffusion layer, it was verified that an n-diffusion layer technique was an excellent way to realize a very small width of a source region (W/sub s/), resulting in an larger I/sub MAX/ and a higher BV simultaneously, and it was desirable to employ an n-diffusion layer having a slightly larger junction depth (X/sub j/) than the depth of a gate trench (L/sub T/)(L/sub T/ < X/sub j/ < 1.3L/sub T/) into a RG SiC SIT with a small width of the source region (W/sub s/ /spl ap/ 0.5 /spl mu/m).
A solution to an open problem by Knuth

In Knuth [2] the problem of minimizing the number of sets of states required for his parsing algorithm is raised as an open question. We solve this problem by showing it is equivalent to that of finding the minimal representation for an incompletely specified finite automaton. A solution may thus be obtained using the known methods of the latter. This result may be viewed in contrast to Pager [8] and [9] where it is shown that it is not generally possible to make optimizations of this kind.
A Unified Framework for Photometric Redshifts

We present a rigorous mathematical solution to photometric redshift estimation and the more general inversion problem. The challenge we address is to meaningfully constrain unknown properties of astronomical sources based on given observables, usually multicolor photometry, with the help of a training set that provides an empirical relation between the measurements and the desired quantities. We establish a formalism that blurs the boundary between the traditional empirical and template-fitting algorithms, as both are just special cases that are discussed in detail to put them in context. The new approach enables the development of more sophisticated methods that go beyond the classic techniques to combine their advantages. We look at the directions for further improvement in the methodology, and examine the technical aspects of practical implementations. We show how training sets are to be constructed and used consistently for reliable estimation.
Analysis and visualization of category membership distribution in multivariate data

Abstract This paper reports on some advances in generic data processing procedures with focus on a specific materials discovery and design task. The task is to predict whether a new ternary materials system would be compound forming or not, with the prediction to be based on knowledge of many other known exemplars. The activities and results of three related efforts are described in condensed form in this paper. In one effort, using a combination of clustering and mapping procedures, an accuracy of more than 99% was attained in predicting the category status (compound forming or not) of new ternary systems. A second effort addressed the question of how to identify redundant or superfluous features. A procedure for identifying the extent of functional dependency amongst features was developed. That procedure can be used to remove redundant features. A third effort addressed the question of how to obtain reduced dimension representations of multivariate data, albeit at the cost of loss of some information. Visualizations of low-dimensional representations can be helpful in building up holistic views of data space for use in exploration and discovery of new materials.
Research on the Method of GPS Height Conversion Based on Terrain Correction

In this paper, through the surface of polynomial fitting precision analysis, obtains fitting after converting precision for normal height is mainly affected by the rate of change vertical deflection and higher order termsalso influenced by local terrain correction. The undulating topography is deduced and the calculation formula of cause height anomaly, this method is applicable to the complex terrain of area, will dividend increase formula one of the smaller constant, the calculating process of the intermediate results are returning to normal range, effectively avoid the central region of the singular integral. In the terrain change large region, attend to the influence of terrain correction, the surface fitting method for elevation conversion, can effective improve GPS elevation fitting the precision of the conversion.
RELAXATION OF WARPED DISKS: THE CASE OF PURE HYDRODYNAMICS

Orbiting disks may exhibit bends due to a misalignment between the angular momentum of the inner and outer regions of the disk. We begin a systematic simulational inquiry into the physics of warped disks with the simplest case: the relaxation of an unforced warp under pure fluid dynamics, i.e., with no internal stresses other than Reynolds stress. We focus on the nonlinear regime in which the bend rate is large compared to the disk aspect ratio. When warps are nonlinear, strong radial pressure gradients drive transonic radial motions along the disk's top and bottom surfaces that efficiently mix angular momentum. The resulting nonlinear decay rate of the warp increases with the warp rate and the warp width, but, at least in the parameter regime studied here, is independent of the sound speed. The characteristic magnitude of the associated angular momentum fluxes likewise increases with both the local warp rate and the radial range over which the warp extends; it also increases with increasing sound speed, but more slowly than linearly. The angular momentum fluxes respond to the warp rate after a delay that scales with the square root of the time for sound waves to cross the radial extent of the warp. These behaviors are at variance with a number of the assumptions commonly used in analytic models to describe linear warp dynamics.
An accurate numerical one-dimensional solution of the p-n junction under arbitrary transient conditions

Abstract A numerical iterative method of solution of the one-dimensional basic two-carrier transport equations describing the behavior of semiconductor junction devices under arbitrary transient conditions is presented. The method is of a very general character: none of the conventional assumptions and restrictions are introduced and freedom is available in the choice of the doping profile, recombination-generation law, mobility dependencies, injection level, and boundary conditions applied solely at the external contacts. For a specified arbitrary input signal of either current or voltage as a function of time, the solution yields terminal properties and all the quantities of interest in the interior of the device (such as mobile carrier and net electric charge densities, electric field, electrostatic potential, particle and displacement currents) as functions of both position and time. Considerable attention is focused on the numerical analysis of the initial-value-boundary-value problem in order to achieve a numerical algorithm sufficiently sound and efficient to cope with the several fundamental difficulties of the problem, such as stability conditions related to the discretization of partial differential equations of the parabolic type, small differences between nearly equal numbers, and the variation of most quantities over extremely wide ranges within short regions. Results for a particular n + - p single-junction structure under typical external excitations are reported. The iterative scheme of solution for a single device is applicable also to ensembles of active and passive circuit elements. As a simple example, resutls for the combination of an n + - p diode and an external resistor, analyzed under switching conditions, are presented. The inductive behavior of the device for high current pulses, and storage and recovery phenomena under forward-to-reverse bias switching, are also illustrated. ‘Exact’ and conventional approximate analytical results are compared and discrepancies are exposed.
MODERN LIBOR MARKET MODELS: USING DIFFERENT CURVES FOR PROJECTING RATES AND FOR DISCOUNTING

We introduce an extended LIBOR market model that is compatible with the current market practice of building different yield curves for different tenors and for discounting. The new paradigm is based on modeling the joint evolution of FRA rates and forward rates belonging to the discount curve. We will start by analyzing the basic lognormal case, then we will add stochastic volatility. The dynamics of FRA rates under different measures will be obtained and closed form formulas for caplets and swaptions derived in the lognormal and Heston (1993) cases.
Vertical and torsional impedances for radially inhomogeneous viscoelastic soil layers

A study of the dynamic impedances of thin, infinite viscoelastic soil layers with a circular hole is made considering a continuous, ramp-like radial variation for the shear modulus of the material. Both vertically and torsionally excited systems are examined. The impedances are evaluated over wide ranges of the parameters involved and compared with those obtained both for homogeneous layers, and for inhomogeneous layers with discontinuous variations in shear modulus. In addition, a simple approximate method of analysis based on the Galerkin approach is presented for vertically excited layers, and it is used to assess the parameters that control their high-frequency response.
Oh, won’t you stay? Predictors of faculty intent to leave a public research university

Understanding and predicting faculty intent to leave is important to the development of improved conceptual frameworks of faculty success as well as the implementation of effective retention strategies for academic leaders and institutions that invest considerable resources in recruitment, institutional support, and compensation. This study examined the relationship between various research-based factors and faculty intent to leave by integrating components identified in the extant literature for employee turnover more generally and faculty intent to leave more specifically. The results of binary logistic regression models identified workplace stress, being in a “soft-pure” discipline, fewer years of service at the university, and higher research productivity as key predictors of faculty having considered leaving for another institution. Key predictors for faculty having considered leaving academe altogether were being in a “hard-applied” discipline, not having a spouse or partner, a perceived lack of support, a perceived lack of fit, stress of raising a family, and dissatisfaction with certain aspects of the “faculty job”. The implications for research, policy, and practice are discussed.
Membrane reactors for catalytic series and series-parallel reactions

Abstract The use of membrane reactors to improve the yield of intermediate products of series and series-parallel heterogeneous catalytic reactions has been investigated. For series reactions the most critical dimensionless parameters related to improving the yield are a Damkohler-Peclet number product (rate of reaction relative to rate of membrane permeation) and the permeability of the intermediate product relative to the reactant. The relative inert gas sweep rate, the pressure differential between the reactant and sweep zones, and the rate of the desired reaction relative to the undesired reaction also affect performance. When series-parallel reactions are considered the relative permeabilities of the reactants are also important in addition to the critical parameters identified for series reactions. For both classes of reactions, mathematical models have been used to identify ranges of these parameters where a membrane reactor can substantially increase the yield of intermediate products compared to a conventional packed bed reactor.
A proposal for a computer compiler

In recent years digital computers have been applied, with great success, to the automation of an increasing variety of tasks in the design of digital systems, from the printing of wiring tables and the drawing of logical diagrams to the optimization, according to certain criteria, of the layout of components and wiring, and even the actual computer-controlled production of subassemblies such as printed circuit boards or integrated circuits. Similarly, the design of circuits, especially those involving nonlinear elements, has been made easier by computer programs (e.g., which perform tolerance analyses). On the system level, the use of digital computers has been limited to tasks which are equally mechanical, such as programs which check for violations of fan-in, fan-out, and cascading rules.
The aggregation of imprecise probabilities

Abstract Two methods are presented for the aggregation of imprecise probabilities elicited from a group of experts in terms of betting rates. In the first method, the experts bet with a common opponent subject to limits on their personal betting stakes, and their individual and aggregate beliefs are represented by confidence-weighted lower and upper probabilities. This method is applicable to situations in which the events in question are discrete, few in number, and ambiguous in nature, where interest centers on the degree of consensus or dissensus and on the reconciliation of incoherence among a small group of experts. In the second method, the experts bet directly with each other as a means of reconciling incoherence, and their beliefs are represented by lower and upper risk neutral probabilities—i.e., products of probabilities and relative marginal utilities for money. The latter method is applicable to situations in which many individuals jointly assess probability distributions for large numbers of events or continuous random variables. In both methods, the fundamental concept of probability is an interpersonal one, with irreducible game-theoretic elements.
Templated Synthesis of Vanadium Borophosphate Cluster Anions.

Hydrothermal synthesis provides new vanadium borophosphates. BP2O10 trimers and V2O8 dimers are connected by common oxygen atoms to give a building unit of composition (VO)2BP2O10. Four-, five-, and six-rings are formed by further connection of these units; the first case is shown schematically. The ring size of the anion is determined by the size of the specific cation used in the synthesis.
Do massive Brans--Dicke theories of gravitation imitate Brans--Dicke theories with nonzero divergence of energy-momentum tensor

Acharya and Hogan (1973) have introduced a massive scalar field into the usual Brans-Dicke (1961) theory of gravitation. Formally they obtain certain field equations. The assumption of a nonzero divergence for T mu nu (or equivalently the introduction of sources) formally imitates a massive Brans-Dicke and satisfies the condition of Acharya and Hogan that the theory be indistinguishable with the classical test of the Einstein theory. Although it was shown elsewhere that the modified Brans-Dicke theory agrees with the classical test under certain conditions, there were no specified limits on omega, a similar circumstance discovered by Acharya and Hogan for the massive scalar field.
Organizational Failure and Intraprofessional Status Loss

We examine variation in intraprofessional status changes for employees displaced by organizational failure. We propose that failure-related reductions in bargaining power are moderated by individual status characteristics that influence potential employers' evaluations of job candidates and, therefore, individuals' status loss risks. Treating a prominent law firm's failure as a quasi-experiment, we test our arguments by analyzing 224 firm partners' transitions to subsequent employers. Most partners regained employment at firms of lower status than the failed firm. But, independent of their demonstrated productivity, a partner's likelihood of status loss increased with tenure in the failed firm's partnership and decreased with educational prestige. These results suggest not only that organizational failure can diminish cumulative career advantages but also that status characteristics that enable attainment, such as education, can protect individuals against status loss.
Magnetic Fields in Stellar Jets

Although several lines of evidence suggest that jets from young stars are driven magnetically from accretion disks, existing observations of field strengths in the bow shocks of these flows imply that magnetic fields play only a minor role in the dynamics at these locations. To investigate this apparent discrepancy we performed numerical simulations of expanding magnetized jets with stochastically variable input velocities with the AstroBEAR MHD code. Because the magnetic field B is proportional to the density n within compression and rarefaction regions, the magnetic signal speed drops in rarefactions and increases in the compressed areas of velocity-variable flows. In contrast, B ~ n0.5 for a steady state conical flow with a toroidal field, so the Alfven speed in that case is constant along the entire jet. The simulations show that the combined effects of shocks, rarefactions, and divergent flow cause magnetic fields to scale with density as an intermediate power 1 > p > 0.5. Because p > 0.5, the Alfven speed in rarefactions decreases on average as the jet propagates away from the star. Hence, a typical Alfven velocity in the jet close to the star is significantly larger than it is in the rarefactions ahead of bow shocks at larger distances. We find that the observed values of weak fields at large distances are consistent with strong fields required to drive the observed mass loss close to the star. Typical velocity perturbations, which form shocks at large distances, will produce only magnetic waves close to the star. For a typical stellar jet the crossover point inside which velocity perturbations of 30-40 km s-1 no longer produce shocks is ~300 AU from the source.
Heat kernel expansions on the integers and the Toda lattice hierarchy

We consider the heat equation ut = Lu where L is a second-order difference operator in a discrete variable n. The fundamental solution has an expansion in terms of the Bessel functions of imaginary argument. The coefficients αk(n, m) in this expansion are analogs of Hadamard’s coefficients for the (continuous) Schrodinger operator.
Noncommutative Lp structure encodes exactly Jordan structure

Abstract We prove that for all 1 ⩽ p ⩽ ∞ , p ≠ 2 , the L p spaces associated to two von Neumann algebras M , N are isometrically isomorphic if and only if M and N are Jordan *-isomorphic. This follows from a noncommutative L p Banach–Stone theorem: a specific decomposition for surjective isometries of noncommutative L p spaces.
Cooperative Relay Broadcast Channels

The capacity regions are investigated for two relay broadcast channels (RBCs), where relay links are incorporated into two-user broadcast channels to support user cooperation. In the first channel, the partially cooperative RBC, only one user in the system acts as a relay. An achievable rate region is derived based on the relay using the decode-and-forward scheme. An outer bound on the capacity region is derived and is shown to be tighter than the cut-set bound. For the special case where the partially cooperative RBC is degraded, the achievable rate region is shown to be the capacity region. Two Gaussian cases of the partially cooperative RBC are studied. For the system where the additive white Gaussian noise (AWGN) term at one receiver is a degraded version of the other, which we refer to as the D-AWGN partially cooperative RBC, the capacity region is established. For the system where the AWGN term at one receiver is independent of the other, which we refer to as the AWGN partially cooperative RBC, inner and outer bounds on the capacity region are derived and are shown to be close. Furthermore, it is shown that feedback does not increase the capacity region for the degraded partially cooperative RBC, but that it improves the capacity region for the nondegraded version. In particular, feedback improves the capacity region for the AWGN partially cooperative RBC. In the second channel model being studied in the paper, the fully cooperative RBC, both users can act as relay nodes. All the results for the partially cooperative RBC are correspondingly generalized to the fully cooperative RBC. In particular, capacity regions are established for the degraded and D-AWGN fully cooperative RBCs. The capacity region is also established for the fully cooperative RBC with feedback. It is further shown that the AWGN fully cooperative RBC has a larger achievable rate region than its partially cooperative counterpart. The results illustrate that relaying and user cooperation are powerful techniques for improving the capacity of broadcast channels
A New Partition Identity Coming from Complex Dynamics

We present a new identity involving compositions (i.e., ordered partitions of natural numbers). The formula has its origin in complex dynamical systems and appears when counting, in the polynomial family $$\{ f_{c} :z \mapsto z^{d} + c\} ,$$ periodic critical orbits with equivalent itineraries. We give two different proofs of the identity; one following the original approach in dynamics and another with purely combinatorial methods.
The relative abundance of neon and magnesium in the solar corona

A technique is proposed for specifically determining the relative solar coronal abundance of neon and magnesium. The relative abundance is calculated directly from the relative intensity of the resonance lines of Ne X (12.134A) and Mg XI (9.169A) without the need for the development of a detailed model of the thermal structure of the corona. Moderate resolution Bragg crystal spectrometer results from the OVI-10 satellite were used to determine a coronal neon to magnesium relative abundance of 1.47 + or - 0.38. The application of this technique to a recent higher resolution rocket observation gave an abundance ratio of approximately 0.93 + or - 0.15.
Molecular imaging of cancer with copper-64 radiopharmaceuticals and positron emission tomography (PET).

Molecular imaging has evolved over the past several years into an important tool for diagnosing, understanding, and monitoring disease. Molecular imaging has distinguished itself as an interdisciplinary field, with contributions from chemistry, biology, physics, and medicine. The cross-disciplinary impetus has led to significant achievements, such as the development of more sensitive imaging instruments and robust, safer radiopharmaceuticals, thereby providing more choices to fit personalized medical needs. Molecular imaging is making steadfast progress in the field of cancer research among others. Cancer is a challenging disease, characterized by heterogeneity, uncontrolled cell division, and the ability of cancer cells to invade other tissues. Researchers are addressing these challenges by aggressively identifying and studying key cancer-specific biomarkers such as growth factor receptors, protein kinases, cell adhesion molecules, and proteases, as well as cancer-related biological processes such as hyp...
Oxidation of 4-methoxyanilines to 1,4-benzoquinones using ceric ammonium nitrate (CAN)

Treatment of substituted 4-methoxyanilines with ceric ammonium nitrate in a 1:1 mixture of water and acetonitrile resulted in the formation of 1,4-benzoquinones in acceptable yields.
Kaon Weak Decays in Chiral Theories

The ten nonleptonic weak decays K→2π, K→ 3π, KL→2γ, KS→2γ, KL→π02γ, are predicted for a chiral pole model based on the linear sigma model theory which automatically satisfies the partial conservation of axial current (PCAC) hypothesis. These predictions, agreeing with data to the 5% level and containing no or at most one free parameter, are compared with the results of chiral perturbation theory (ChPT). The latter ChPT approach to one-loop level is known to contain at least four free parameters and then predicts a KL→π0γγ rate which is 60% shy of the experimental value.
Product Superposition for MIMO Broadcast Channels

This paper considers the multiantenna broadcast channel without transmit-side channel state information. For this channel, it has been known that when all receivers have channel state information (CSIR), the degrees of freedom (DoFs) cannot be improved beyond what is available via time-division multiple access. The same is true if none of the receivers possess CSIR. This paper shows that an entirely new scenario emerges when receivers have unequal CSIR. In particular, orthogonal transmission is no longer DoF optimal when one receiver has CSIR and the other does not. A multiplicative superposition is proposed for this scenario and shown to attain the optimal DoFs under a wide set of antenna configurations and coherence lengths. Two signaling schemes are constructed based on the multiplicative superposition. In the first method, the messages of the two receivers are carried in the row and column spaces of a matrix, respectively. This method works better than orthogonal transmission while reception at each receiver is still interference-free. The second method uses coherent signaling for the receiver with CSIR, and Grassmannian signaling for the receiver without CSIR. This second method requires interference cancellation at the receiver with CSIR, but achieves higher DoF than the first method.
Theory of Optical Information Storage in Solids

In photography, information is stored in a medium which is essentially two-dimensional. Three-dimensional optical storage is possible in semitransparent colored materials, like alkali halides with color centers. With the use of coherent light sources, like lasers, large amounts of information can be stored in the volume, and retrieved with little interference. The storage of information is accomplished by the formation of interference patterns between each two plane parallel waves. This paper develops the theory of this form of storage. It turns out that the information storage capacity is as if every little cube with sides equal to the wavelength of light acts as an independent information storage cell, and the essential noise in recovering this information is only the statistical fluctuation in the number of color centers in such a cube. The storage capacity is therefore of the order of 1012–1013 bits per cm3. The main property of this way of information storage is the appearance of a “ghost image,” partly but not completely analogous to the one described previously. This property makes three-dimensional storage very suitable for associative memories. The theory lends support to Beurle’s proposed mechanism of information storage in the brain.
Does Prekindergarten Improve School Preparation and Performance

Prekindergarten programs are expanding rapidly but evidence on their effects is limited. Using rich data from Early Childhood Longitudinal Study, we estimate the effects of prekindergarten on children’s school readiness. We find that prekindergarten is associated with higher reading and mathematics skills at school entry, but also higher levels of behavior problems. By the spring of first grade, estimated effects on academic skills have largely dissipated, but the behavioral effects persist. Larger and longer lasting associations with academic gains are found for disadvantaged children. Finally, we find some evidence that prekindergartens located in public schools do not have adverse effects on behavior problems.
On the sandpile group of regular trees

The sandpile group of a connected graph is the group of recurrent configurations in the abelian sandpile model on this graph. We study the structure of this group for the case of regular trees. A description of this group is the following: Let T(d,h) be the complete d-regular tree of depth h and let V be the set of its vertices. Denote the adjacency matrix of T(d,h) by A and consider the modified Laplacian matrix @[email protected]?dI-A. Let the rows of @D span the lattice @L in Z^V. The sandpile group G(d,h) of T(d,h) is Z^V/@L. We compute the rank, the exponent, the order, and other structural parameters of the abelian group G(d,h). We find a cyclic Hall-subgroup of order (d-1)^h. We prove that the rank of G(d,h) is (d-1)^h and that G(d,h) contains a subgroup isomorphic to Z"d^(^d^-^1^)^^^h; therefore, for all primes p dividing d, the rank of the Sylow p-subgroup is maximal (equal to the rank of the entire group). We find that the base-(d-1) logarithm of the exponent and of the order are asymptotically 3h^2/@p^2 and c"d(d-1)^h, respectively. We conjecture an explicit formula for the ranks of all Sylow subgroups.
Self-Similar Solutions for Relativistic Shocks Emerging from Stars with Polytropic Envelopes

We consider a strong ultrarelativistic shock moving through a star whose envelope has a polytrope-like density profile. When the shock is close to the star's outer boundary, its behavior follows the self-similar solution given by Sari for implosions in planar geometry. Here we outline this solution and find the asymptotic solution as the shock reaches the star's edge. We then show that the motion after the shock breaks out of the star is described by a self-similar solution remarkably like the solution for the motion inside the star. In particular, the characteristic Lorentz factor, pressure, and density vary with time according to the same power laws both before and after the shock breaks out of the star. After emergence from the star, however, the self-similar solution's characteristic position corresponds to a point behind the leading edge of the flow rather than at the shock front, and the relevant range of values for the similarity variable changes. Our numerical integrations agree well with the analytic results both before and after the shock reaches the star's edge.
The metabolism of androgens in central neuroendocrine tissues

Although prehormone androgens such as testosterone and androstenedione are converted to ring A reduced products such as dihydrotestosterone and androstanedione in central tissues (brain and pituitary gland), there is ample evidence suggesting that many central reproductive functions of these prehormone androgens may require their conversion to estrogens. Because of this, we have sought and demonstrated the local in vitro and in vivo conversion of androstenedione and testosterone to estrone and estradiol in central tissues from humans, rhesus monkeys, rabbits, rats and mice. Central aromatizing activity is greater in males than in females and is affected by castration and sex steroid and antiandrogen pretreatment. The anterior hypothalamus is the most actively aromatizing central tissue. However, because of the importance of the limbic system in neuroendocrine rhythms, the control of gonadotrophins and the onset of puberty, it has also been investigated, and has been found to convert androgens to estrogens. We believe that the classical concept of androgen action must be enlarged to encompass central effects that require the aromatization of androgens as well as those requiring ring A reduction.
Nonlocal Magnetization Dynamics in Ferromagnetic Hybrid Nanostructures

Two complementary effects modify the GHz magnetization dynamics of nanoscale heterostructures of ferromagnetic and normal materials relative to those of the isolated magnetic constituents: On the one hand, a time-dependent ferromagnetic magnetization pumps a spin angular-momentum flow into adjacent materials and, on the other hand, spin angular momentum is transferred between ferromagnets by an applied bias, causing mutual torques on the magnetizations. These phenomena are manifestly nonlocal: they are governed by the entire spin-coherent region that is limited in size by spin-flip relaxation processes. We review recent progress in understanding the magnetization dynamics in ferromagnetic heterostructures from first principles, focusing on the role of spin pumping in layered structures. The main body of the theory is semiclassical and based on a mean-field Stoner or spin-density--functional picture, but quantum-size effects and the role of electron-electron correlations are also discussed. A growing number of experiments support the theoretical predictions. The formalism should be useful to understand the physics and to engineer the characteristics of small devices such as magnetic random-access memory elements.
Higher $l$-adic Abel-Jacobi mappings and filtrations on Chow groups

We define a filtration on the Chow groups of a smooth projective variety X over a field k by using the cycle map into continuous l-adic etale cohomology. The main theorem says that if k is a function field in one variable over a finite field, this filtration for zero cycles is of length at most one modulo the kernel of the cycle map.
Influence of impurity scattering on the conductance anomalies of quantum point contacts with lateral spin-orbit coupling

We have recently shown that asymmetric lateral spin orbit coupling (LSOC) resulting from the lateral in-plane electric field of the confining potential of a side-gated quantum point contact (QPC) can be used to create a strongly spin-polarized current by purely electrical means1 in the absence of applied magnetic field. Using the non-equilibrium Green function formalism (NEGF) analysis of a small model QPC2, three ingredients were found to be essential to generate the strong spin polarization: an asymmetric lateral confinement, a LSOC induced by the lateral confining potential of the QPC, and a strong electron-electron (e-e) interaction. In this paper, NEGF is used to study how the spin polarization is affected by the presence of impurities in the central portion of the QPC. It is found that the number, location, and shape of the conductance anomalies, occurring below the first quantized conductance plateau (G 0 =2e2/h), are strongly dependent on the nature (attractive or repulsive) and the locations of the impurities. We show that the maximum of the conductance spin polarization is affected by the presence of impurities. For QPCs with impurities off-center, a conductance anomaly appears below the first integer step even for the case of symmetric bias on the two side gates. These results are of practical importance if QPCs in series are to be used to fabricate all-electrical spin valves with large ON/OFF conductance ratio.
Associated production of gauginos and gluinos at hadron colliders in next-to-leading order SUSY-QCD.

Abstract We report a next-to-leading order (NLO) calculation of the production of gaugino-like charginos ( χ ± ) and neutralinos ( χ 0 ) in association with gluinos ( g ) at hadron colliders, including the strong corrections from colored particles and sparticles. We predict inclusive cross sections at the Fermilab Tevatron and CERN LHC. The NLO cross sections are more stable against variations in the hard-scattering scale parameter and are greater than the LO values.
Joe Cannon and the Minority Party: Tyranny or Bipartisanship?

The minority party is rarely featured in empirical research on parties in legislatures, and recent theories of parties in legislatures are rarely neutral and balanced in their treatment of the minority and majority parties. This article makes a case for redressing this imbalance. We identified four characteristics of bipartisanship and evaluated their descriptive merits in a purposely hostile testing ground: during the rise and fall of Speaker Joseph G. Cannon, �the Tyrant from Illinois.� Drawing on century-old recently discovered records now available in the National Archives, we found that Cannon was anything but a majority-party tyrant during the important committee-assignment phase of legislative organization. Our findings underscore the need for future, more explicitly theoretical research on parties-in-legislatures.
Thermoelastic flutter models for elements of flexible satellites

Models of thermally induced flutter of the flexible elements of a satellite, such as beams, circular plates, and cylindrical shells, have been obtained. These models form the necessary blocks for analyzing the motion of satellites. The heat input is considered to be caused by solar radiation. The partial differential equations for all the elements of the satellite are linear in the space-dependent variables and nonlinear in the time-dependent variables. These equations are coupled through the motion of the center of mass of the satellite. Galerkin's method has been used to remove the space-dependence of these equations.
Saucy-Marbet Rearrangements of Alkynyl Halides in the Synthesis of Highly Enantiomerically Enriched Allenyl Halides.

Abstract A stereospecific Saucy–Marbet rearrangement of alkynyl halides is described here. These rearrangements provide an entry to highly enantiomerically enriched allenyl bromides and chlorides through excellent chirality transfer and the preservation of optical integrity of alkynyl halides.
Direct work station to remote computer communications via satellite

This paper addresses communications between office CRT/keyboard intelligent work stations and a remote computer installation using a satellite. The travel industry is used as an example of an industry that could employ direct satellite communications. The office will have a small, inexpensive earth terminal on the premises to support several work stations at that location. A commercial communications satellite with high-gain antenna beams supports the small office terminals. Performance of several channel-sharing protocols is described, and an optimum protocol for this application is discussed. For the example studied, a reservation assignment protocol with slotted Aloha orderwire was selected for its high efficiency. This protocol will support 130 office earth terminals (approximately 390 work stations) in a single satellite channel. The system provides highly responsive service time (1 1/2 seconds average). The cost of digital communications via satellite channels and terrestrial links is compared, and the advantages of satellite communications are discussed.
The Angular Momentum Evolution of Very Low Mass Stars

We present theoretical models of the angular momentum evolution of very low mass stars (0.1-0.5 M☉). We also present models of solar analogs (0.6-1.1 M☉) for comparison with previous work. We investigate the effect of rotation on the effective temperature and luminosity of these stars. Rotation lowers the effective temperature and luminosity of the models relative to standard models of the same mass and composition. We find that the decrease in Teff and L can be significant at the higher end of our mass range but becomes small below 0.4 M☉. The effects of different assumptions about internal angular momentum transport are discussed. Formulae for relating Teff to mass and vrot are presented. We demonstrate that the kinetic energy of rotation is not a significant contribution to the luminosity of low-mass stars. Previous studies of the angular momentum evolution of low-mass stars concentrated on solar analogs and were complicated by uncertainties related to the internal transport of angular momentum. In this paper we extend our theoretical models for the angular momentum evolution of stars down to 0.1 M☉. We compare our models to rotational data from young open clusters of different ages to infer the rotational history of low-mass stars and the dependence of initial conditions and rotational evolution on mass. We find that the qualitative conclusions for stars below 0.6 M☉ do not depend on the assumptions about internal angular momentum transport with the exception of a zero-point shift in the angular momentum loss saturation threshold. We argue that this makes these low-mass stars ideal candidates for the study of the angular momentum loss law and distribution of initial conditions. For stars with masses between 0.6 and 1.1 M☉, scaling the saturation threshold by the Rossby number can reproduce the observed mass dependence of the stellar angular momentum evolution. We find that neither models with solid-body rotation nor differentially rotating models can simultaneously reproduce the observed stellar spin-down in the 0.6-1.1 M☉ range and for stars between 0.1 and 0.6 M☉. We argue that the most likely explanation is that the saturation threshold drops more steeply at low masses than would be predicted with a simple Rossby scaling. In young clusters there is a systematic increase in the mean rotation rate with decreased temperature below 3500 K (0.4 M☉). This suggests either inefficient angular momentum loss or mass-dependent initial conditions for stars near the fully convective boundary.
Gender, race, and the state legislature: A research note on the double disadvantage hypothesis

Abstract The “double disadvantage” hypothesis stipulates that black females are politically disadvantaged twice (once by gender, once by race). This hypothesis suggests that because of both their race and gender, black women will find it especially difficult to compete successfully in electoral politics in the United States. This leads one to expect that proportionately fewer black women would hold elective office than is true for other groups (e.g. white women, black men, white men). It would also suggest that black women could overcome these disadvantages only if they exceed their gender and racial counterparts in certain preparatory background characteristics such as education and occupational prestige. We examine these issues, using data on state legislator's backgrounds. We find that only one of the two necessary conditions to corroborate the “double disadvantage” hypothesis is met. Generally, our findings support the conclusions of previous research.
Secular instability of g‐modes in rotating neutron stars

Gravitational radiation tends to drive gravity modes in rotating neutron stars to become unstable. For an inviscid star, the instability sets in when the rotation frequency is about 0.7 times the corresponding mode frequency of the non-rotating star. Neutron stars with spin frequencies ≳100 Hz are susceptible to this instability, with a growth time of the order of years. However, it is likely that viscous dissipation suppresses the instability except for a narrow range of temperatures around 109 K. We also show that the viscosity-driven instability of g-modes is absent.