cssi/SciSciGPT-SciSciNet huggingface dataset:
Neutrino pair emission from Cooper pair breaking and recombination in superfluid quark matter

Abstract For the low energy Standard Model neutrino-matter interactions, we calculate neutrino pair ( ν ν ) emissivities in superfluid quark matter. Just below the critical temperature, Cooper pairs continuously break and recombine, resulting in the emission of ν ν pairs with a rate that greatly exceeds the standard quark modified Urca and bremsstrahlung rates. At the same baryon density in baryonic and quark matter, the ratio of baryon to quark ν ν emissivities lies in the range 2–5 for the densities of interest in the long-term cooling of solar mass compact stars. We also find that in matter containing hyperons, ν ν emission can occur with hyperons of all species.
The expected time to end the tug-of-war in a wedge

Using a solution of a nonhomogeneous partial differential equation involving the p-Laplacian, we study the finiteness of the expected time to end the tug-of-war in a wedge.
Predictability and legal evolution

The change of legal rules is unavoidable, since the legal system must react to socioeconomic developments. Using the conclusions of the (imperfect) efficiency of the common law and a framework complementary to public choice theory, this essay considers a legal system's choice of whether its rules change rarely by large increments or frequently by small increments. The drawback of frequent changes has been alleged to be unpredictability. The purpose of this analysis is to construct an analytical model of the two evolutionary legal systems which may allow their evaluation. The analysis may apply to the comparison of civil and common law or the desirability of a practice of liberal interpretation by the judiciary. Society is modeled as a random evolution (diffusion). Law must keep up through infrequent but large changes or small, frequent changes. Uncertainty about the law is studied in the context of this model. Neither system appears better at tracking socioeconomic evolution, but frequent small changes are preferable for risk-averse individuals. The analysis suggests that predictability is not an argument against judicial discretion.
Monte-Carlo study of correlations in quantum spin chains at non-zero temperature

Antiferromagnetic Heisenberg spin chains with various spin values (S=1/2,1,3/2,2,5/2) are studied numerically with the quantum Monte-Carlo method. Effective spin S chains are realized by ferromagnetically coupling n=2S antiferromagnetic spin chains with S=1/2. The temperature dependence of the uniform susceptibility, the staggered susceptibility, and the static structure factor peak intensity are computed down to very low temperatures, . The correlation length at each temperature is deduced from numerical measurements of the instantaneous spin-spin correlation function. At high temperatures, very good agreement with exact results for the classical spin chain is obtained independent of the value of S. For the S=2 chain which has a gap , the correlation length and the uniform susceptibility in the temperature range are well predicted by the semi-classical theory of Damle and Sachdev.
Monopolistic Competition and Preference Diversity

approach. Our model is especially attractive because it starts from economic primitives: a specification of the set of possible individual preference patterns. It shows how specific properties of the distribution of preferences translate into properties of aggregate demand. This allows us to understand the relationship between the distribution of preferences and the degree to which the market introduces biases in product selection. This paper presents a general model of the demand for differentiated products which has as special cases two of the most popular approaches used to analyse welfare and competition in monopolistically competitive markets: the model of spatial competition on the circle and the model of symmetric aggregate demand. The circle model is attractive because both demand and costs have a definite (and easy to visualize) physical foundation and because it is tractable. Salop (1979) provides an exemplary modem analysis. With this model one can analyze the relationship between the optimal amount of product variety and the amount which a monopolistically competitive market will support. In many plausible cases competition produces too much variety. Such a strong conclusion raises questions of robustness. Almost simultaneously, Spence (1976) and Dixit and Stiglitz (1977) developed an alternative approach to monopolistic competition, based upon the Chamberlinian assumption of symmetry (see also Shubik (1959)). Rather than specifying a distribution of preferences and deriving demand through aggregation (as did Salop and his predecessors), these authors started by specifying a symmetric aggregate benefit function indicating how social welfare depends on the amounts of the various products supplied. Both Spence and Dixit-Stiglitz were able to show that the welfare conclusions from the circle model were not robust: depending on the functional form of the benefit function, equilibrium may entail either excessive or insufficient product variety.1 The assumption of symmetric demand has proven fruitful in the analysis of many economic problems. It is therefore natural to ask what distribution of tastes would give
Molecular dynamics investigations of the ablator/fuel interface during early stages of inertial confinement fusion

At the National Ignition Facility, high-powered laser beams are focused into a hohlraum, which in turn produces x-rays that heat and compress a small spherical target to generate fusion reactions. A critical issue in achieving this is the understanding of the mix at the ablator/fuel interface. Mixing occurs at various length scales, ranging from atomic inter-species diffusion to hydrodynamic instabilities. Because the ablator/fuel interface is preheated by energy from the incoming shock, it is important to understand the dynamics of the interface before the shock arrives. The interface is in the warm dense matter phase with a deuterium-tritium fuel mixture on one side and a plastic (H, C and O) mixture on the other. We would like to understand various aspects of the evolution of this warm dense mixture, including the state of the interface when the main shock arrives, the role of electric field generation at the interface, and the character and time scales for diffusive-like mixing. We present a molecular dynamics approach to model these processes, in which the ions are treated as classical point particles. Because we must reach extremely large length (many microns) and time scales (many picoseconds), we have also developed a simplified electronic structure model, which includes time- and space-dependent ionization levels, external heating and electron-ion energy exchange. Simulation results are presented and compared with other models and experiments.
Ago-associated human usRNAs and other similar small RNAs

We report the characterization of several subclasses of unusually small RNAs (usRNAs) in human and viral genomes. Prior to our work, two popular, yet incorrect presumptions led to all small RNAs less than 20 bases in length (usRNAs) being thought of as transient degradation products of longer RNAs or as RNAs that cannot be reliably mapped to the genome. In this work, we show that while 100% of usRNAs cannot be mapped reliably to the genomes, ~16% of RNAs as small as 15 bases can be reliably mapped to the genome, corresponding to thousands of new small RNAs. We demonstrate that these 5'-phosphate containing usRNAs are accurately, reproducibly and repeatedly, produced across various tissues, and have very unique biological characteristics, thus contesting the hypothesis that these RNAs can be ignored as transient degradation products. Our observations began with the identification of a Kaposi sarcoma-associated herpesvirus us-K12-1 RNA (17 bases) that is as effective as the K12-1 miRNA in regulating human RAD21, a novel K12-1 target. High-throughput sequencing followed by bioinformatics analysis and molecular profiling reveals a diverse set of human miRNA-derived usRNAs and other non-miRNA-derived usRNAs. Human miRNA-derived usRNAs preferentially match to 5' ends of miRNAs, and are also more likely to associate with the siRNA effector protein Ago2, than Ago1. Many non-miRNA-derived usRNAs associate with Ago proteins and also frequently contain C-rich 3'-specific motifs that are highly position specific, and are overrepresented in comparison to piRNAs and TSSa-RNAs. In summary, our observations suggest that ~ 30% of usRNAs could have evolved to participate in biological processes including gene-silencing.
Electroweak Baryogenesis and Dark Matter with an approximate R-symmetry

It is well known that R-symmetric models dramatically alleviate the SUSY flavor and CP problems. We study particular modifications of existing R-symmetric models which share the solution to the above problems, and have interesting consequences for electroweak baryogenesis and the Dark Matter (DM) content of the universe. In particular, we find that it is naturally possible to have a strongly first-order electroweak phase transition while simultaneously relaxing the tension with EDM experiments. The R-symmetry (and its small breaking) implies that the gauginos (and the neutralino LSP) are pseudo-Dirac fermions, which is relevant for both baryogenesis and DM. The singlet superpartner of the U(1)Y pseudo-Dirac gaugino plays a prominent role in making the electroweak phase transition strongly first-order. The pseudo-Dirac nature of the LSP allows it to behave similarly to a Dirac particle during freeze-out, but like a Majorana particle for annihilation today and in scattering against nuclei, thus being consistent with current constraints. Assuming a standard cosmology, it is possible to simultaneously have a strongly first-order phase transition conducive to baryogenesis and have the LSP provide the full DM relic abundance, in part of the allowed parameter space. However, other possibilities for DM also exist, which are discussed. It is expected that upcoming direct DM searches as well as neutrino signals from DM annihilation in the Sun will be sensitive to this class of models. Interesting collider and Gravity-wave signals are also briefly discussed.
CIDNP Study and Ab-Initio Calculations of Rigid Vinylcyclopropane Systems: Evidence For Delocalized “Ring-Closed” Radical Cations

Abstract The radical cations of three terpenes, sabinene, 1, and α-, 2, and β-thujene, 3, containing vinylcyclopropane functions held rigidly in either an anti- or syn-orientation, have been elucidated by CIDNP studies. The structures assigned to these species are discussed in view of their reactivities and compared with three simplified radical cations, 2-methylenebicyclo[3.1.0]hexane, 4, bicyclo[3.1.0]hex-2-ene, 5, and 5-methylbicyclo[3.1.0]hex-2-ene, 6, calculated by ab initio molecular orbital methods. © 1997 Elsevier Science Ltd.
Turbulent Flow Velocity Between Rotating Co-Axial Disks of Finite Radius

The turbulent flow between two rotating co-axial disks is driven by frictional forces. The prediction of the velocity field can be expected to be very sensitive to the turbulence model used to describe the viscosity close to the walls. Numerical solutions of the Navier–Stokes equations, using a k–e turbulence model derived from Lam and Bremhorst, are presented and compared with experimental results obtained in two different configurations: a rotating cavity and the outflow between a rotating and stationary disk. The comparison shows good overall agreement with the experimental data and substantial improvements over the results of other analyses using the k–e models. Based on this validation, the model is applied to the flow between counterrotating disks and it gives the dependence of the radial variation of the tangential wall shear stress on Rossby number.
Combining qualitative and quantitative constraints in temporal reasoning

Abstract This paper presents a general model for temporal reasoning that is capable of handling both qualitative and quantitative information. This model allows the representation and processing of many types of constraints discussed in the literature to date, including metric constraints (restricting the distance between time points) and qualitative, disjunctive constraints (specifying the relative position of temporal objects). Reasoning tasks in this unified framework are formulated as constraint satisfaction problems and are solved by traditional constraint satisfaction techniques, such as backtracking and path consistency. New classes of tractable problems are characterized, involving qualitative networks augmented by quantitative domain constraints, some of which can be solved in polynomial time using arc and path consistency.
Microwave spectra of the 13C isotopic species of methyl cyanide for the ground and V8=1,2 vibrational levels in the frequency range 17-56 GHz

Abstract The microwave spectrum of 13 C substituted methyl cyanide CH 3 C 14 N was studied for the v 8 = 1, 2, for both single and double 13 C substitutions, with vibrational states in the frequency range of 17 to 56 GHz. In addition, some rotational components for the ground state were remeasured and these results compared to those found in the literature for the naturally occurring isotopic ratios. The frequencies of the 1 ≤ J ≤ 3 components were measured for each vibration and these frequencies used to produce a constant set which can be used to predict overall frequencies of spectral components in the ground and v 8 = 1, 2 up to an accuracy of 100 KHz. Previously obtained experimental data, available from the literature for the naturally occurring isotopes, and our own data for the ground state are presented and compared with the frequencies obtained from a comprehensive equation derived from perturbation techniques.
A mobility-aware file system for partially connected operation

The advent of affordable off-the-shelf wide-area wireless networking solutions for portable computers will result in partial (or intermittent) connectivity becoming the common networking mode for mobile users. This paper presents the design of PFS, a mobility-aware file system specially designed for partially connected operation.PFS supports the extreme modes of full connection and disconnection gracefully, but unlike other mobile file systems, it also provides an interrace for mobility-aware applications to direct the file system in its caching and consistency decisions in order to fully exploit intermittent connectivity. Using PFS, it is possible for an application to maintain consistency on only the critical portions of its data files. Since PFS provides adaptation at the file system level, even unaware applications can 'act' mobile-aware as a result of the transparent adaptation provided by PFS.
Stochastic Integrals and Evolution Equations with Gaussian Random Fields

The paper studies stochastic integration with respect to Gaussian processes and fields. It is more convenient to work with a field than a process: by definition, a field is a collection of stochastic integrals for a class of deterministic integrands. The problem is then to extend the definition to random integrands. An orthogonal decomposition of the chaos space of the random field, combined with the Wick product, leads to the Ito-Skorokhod integral, and provides an efficient tool to study the integral, both analytically and numerically. For a Gaussian process, a natural definition of the integral follows from a canonical correspondence between random processes and a special class of random fields. Also considered are the corresponding linear stochastic evolution equations.
Synthesis and Reactivity of Metallophosphanes

Abstract Aspects of the reactivity of metallophosphanes are presented along with the synthesis and structure determinations for new aluminophosphanes.
Intermolecular Hydroamination of Allenes with N-Unsubstituted Carbamates Catalyzed by a Gold(I) N-Heterocyclic Carbene Complex

Reaction of 2,3-pentadienyl benzoate with benzyl carbamate catalyzed by a 1:1 mixture of (NHC)AuCl and AgOTf in dioxane at 23 °C for 5 h led to isolation of (E)-4-(benzyloxycarbonylamino)-2-pentenyl benzoate in 84% yield as a single regio- and diastereomer. Gold(I)-catalyzed hydroamination was effective for a number of N-unsubstituted carbamates and a range of substituted allenes.
Bestvina's Normal Form Complex and the Homology of Garside Groups

A Garside group is a group admitting a finite lattice generating set \(\mathcal{D}\). Using techniques developed by Bestvina for Artin groups of finite type, we construct K(π, 1)s for Garside groups. This construction shows that the (co)homology of any Garside group G is easily computed given the lattice \(\mathcal{D}\), and there is a simple sufficient condition that implies G is a duality group. The universal covers of these K(π, 1)s enjoy Bestvina's weak nonpositive curvature condition. Under a certain tameness condition, this implies that every solvable subgroup of G is virtually Abelian.
Mercury: a satellite ground station control system

As part of its research program in spacecraft operations, Stanford University's Space Systems Development Laboratory (SSDL) is developing a ground station control system to support advanced command and telemetry operations. Known as Mercury, this control system provides direct human console control, remote human tele-operation, and script/program based autonomous control. Each of these modes supports the ability to configure and monitor station equipment as well as to conduct command and telemetry operations with spacecraft. The Mercury system is being implemented on SSDL's OSCAR-class amateur radio ground station. Mercury is currently being used to operationally test two SSDL microsatellites being prepared for launch in 1999. This paper describes the design and operation of the Mercury system, its implementation in the SSDL OSCAR station, its use to conduct mission operations with SSDL microsatellites, and its role in SSDL's multi-satellite, multiground station mission operations architecture.
The “Critical” Elements of Illness Management and Recovery: Comparing Methodological Approaches

This study examined three methodological approaches to defining the critical elements of Illness Management and Recovery (IMR), a curriculum-based approach to recovery. Sixty-seven IMR experts rated the criticality of 16 IMR elements on three dimensions: defining, essential, and impactful. Three elements (Recovery Orientation, Goal Setting and Follow-up, and IMR Curriculum) met all criteria for essential and defining and all but the most stringent criteria for impactful. Practitioners should consider competence in these areas as preeminent. The remaining 13 elements met varying criteria for essential and impactful. Findings suggest that criticality is a multifaceted construct, necessitating judgments about model elements across different criticality dimensions.
Photorelease of primary aliphatic and aromatic amines by visible-light-induced electron transfer.

Visible-light-absorbing tris(bipyridyl)ruthenium(II) has been used to mediate electron transfer to N-methylpicolinium carbamates that undergo C–O bond fragmentation followed by spontaneous carbon dioxide release to give free amines. Release of several aliphatic and aromatic primary amines has been demonstrated under mild conditions using visible light.
Cool Core Bias in Sunyaev–Zel’dovich Galaxy Cluster Surveys

Sunyaev–Zel’dovich (SZ) surveys find massive clusters of galaxies by measuring the inverse Compton scattering of cosmic microwave background off of intra-cluster gas. The cluster selection function from such surveys is expected to be nearly independent of redshift and cluster astrophysics. In this work, we estimate the effect on the observed SZ signal of centrally peaked gas density profiles (cool cores) and radio emission from the brightest cluster galaxy by creating mock observations of a sample of clusters that span the observed range of classical cooling rates and radio luminosities. For each cluster, we make simulated SZ observations by the South Pole Telescope and characterize the cluster selection function, but note that our results are broadly applicable to other SZ surveys. We find that the inclusion of a cool core can cause a change in the measured SPT significance of a cluster between 0.01 and 10% at > z 0.3, increasing with cuspiness of the cool core and angular size on the sky of the cluster (i.e., decreasing redshift, increasing mass). We provide quantitative estimates of the bias in the SZ signal as a function of a gas density cuspiness parameter, redshift, mass, and the 1.4 GHz radio luminosity of the central active galactic nuclei. Based on this work, we estimate that, for the Phoenix cluster (one of the strongest cool cores known), the presence of a cool core is biasing the SZ significance high by ∼6%. The ubiquity of radio galaxies at the centers of cool core clusters will offset the cool core bias to varying degrees.
"Loans for Shares" Revisited

The "loans for shares" scheme of 1995-1996—in which a handful of well-connected businessmen bought stakes in major Russian companies—is widely considered a scandalous affair that had disastrous consequences for the Russian economy. Fifteen years later, the details of the program are reexamined in light of evidence available today. The conventional wisdom about "loans for shares" is analyzed in terms of how much of the market the stakes involved represented; the pricing in terms of international practice; the scheme's place in Russia's increasing wealth inequality; who the biggest beneficiaries were: and the firms' role in Russia's rapid growth after 1999.
The Higgs model with a complex ghost pair

Abstract A higher derivative term is introduced in the kinetic energy of the Higgs lagrangian in the minimal Standard Model. A logically consistent and finite field theory is obtained when some excitations of the Higgs field are quantized with indefinite metric in the Hilbert space. The Landau ghost phenomenon of the ponventional triviality problem is replaced by the state vectors of a complex ghost pair at a finite mass scale with observable physical consequences. It is shown that the ghost states exhibit unusual resonance properties and correspond to a complex conjugate pair of Pauli-Villars regulator masses in the euclidean path integral formulation of the theory. An argument is given that microscopic acausality effects associated with the ghost pair remain undetectable in scattering processes with realistic wave packets, and the S-matrix should exhibit unitarity in the observable sector of the Hilbert space.
Modeling of tritium behavior in ceramic breeder materials

Computer models are being developed to predict tritium release from candidate ceramic breeder materials for fusion reactors. Early models regarded the complex process of tritium release as being rate limited by a single slow step, usually taken to be tritium diffusion. These models were unable to explain much of the experimental data. We have developed a more comprehensive model which considers diffusion and desorption from the grain surface. In developing this model we found that it was necessary to include the details of the surface phenomena in order to explain the results from recent tritium release experiments. A diffusion-desorption model with a desorption activation energy which is dependent on the surface coverage was developed. This model provided excellent agreement with the results from the CRITIC tritium release experiment. Since evidence suggests that other ceramic breeder materials have desorption activation energies which are dependent on surface coverage, it is important that these variations in activation energy be included in a model for tritium release. 17 refs., 12 figs.
X-Ray Pulsars in the Small Magellanic Cloud

XMM-Newton archival data for the Small Magellanic Cloud have been examined for the presence of previously undetected X-ray pulsars. One such pulsar, with a period of 202 s, is detected. Its position is consistent with an early B star in the SMC, and we identify it as a high-mass X-ray binary (HMXB). In the course of this study we determined the pulse period of the possible AXP CXOU J010043.1-721134 to be 8.0 s, correcting an earlier report (Lamb et al.) of a 5.4 s period for this object. Pulse profiles and spectra for each of these objects are presented as well as for a recently discovered (Haberl & Pietsch) 263 s X-ray pulsar. Properties of an ensemble of 24 optically identified HMXB pulsars from the SMC are investigated. The locations of the pulsars and an additional 22 X-ray pulsars not yet identified as having high-mass companions are located predominately in the young (ages ≤3 × 107 yr) star-forming regions of the SMC, as expected on the basis of binary evolution models. We find no significant difference between the distribution of spin periods for the HMXB pulsars of the SMC and that of the Milky Way. For those HMXB pulsars that have Be companions we note an inverse correlation between spin period and maximum X-ray flux density. (This anticorrelation has been previously noted for all X-ray binary pulsars by Stella, White, & Rosner) The anticorrelation for the Be binaries may be a reflection of the fact that the spin periods and orbital periods of Be HMXBs are correlated. We note a similar correlation between X-ray luminosity and spin period for the Be HMXB pulsars of the Milky Way and speculate that exploitation of the correlation could serve as a distance indicator.
Crystal Chemistry of Gallium(I) in Oxides: Ga+-β‘‘-Alumina and GaZr2(PO4)3

Ga+-β‘‘-alumina and GaZr2(PO4)3 have been prepared by ion exchange techniques from Na+-β‘‘-alumina and AgZr2(PO4)3, respectively. The structures of both compounds at room temperature are reported along with that for β‘‘-alumina at 11 K. The coordination chemistries of the Ga(I) cations in the two materials are distinctly different: in Ga+-β‘‘-alumina, the Ga(I) cation displays 3+0-coordination, indicative of a stereochemically active lone pair, with a minimum Ga−O distance of 2.39 A, but in GaZr2(PO4)3, Ga(I) is 6-coordinate with a minimum Ga−O distance of 2.80 A. Both Ga+-β‘‘-alumina and GaZr2(PO4)3 are stable toward oxidation in air up to ∼500 °C. Crystal data are as follows. Ga1.6[(Al10.7Li0.3)O17]: rhombohedral, R3m, Z = 3; for T = 296 K, a = 5.5951(1) A and c = 34.3670(8) A; for T = 11 K, a = 5.5900(1) A and c = 34.3805(8) A. GaZr2(PO4)3: rhombohedral, R3c, Z = 6, a = 8.72198(4) A, c = 23.8820(2) A.
Body cooling attenuates the decrease in maximal oxygen uptake associated with cardiovascular drift during heat stress

Previous research suggests cardiovascular drift (CV drift) is associated with decreased maximal oxygen uptake $$\left( \dot{\hbox{V}}\hbox{O}_{\rm 2max} \right)$$ during heat stress, but more research manipulating CV drift with subsequent measurement of $$\dot{\hbox{V}}\hbox{O}_{\rm 2max}$$ is needed to assess whether this relationship is causal. To assess causation, $$\dot{\hbox{V}}\hbox{O}_{\rm 2max}$$ was measured during the same time interval that CV drift occurred (between 15 and 45 min of submaximal exercise under different conditions of body cooling intended to manipulate CV drift). Ten men completed a control graded exercise test (GXT) in 22°C to measure $$\dot{\hbox{V}}\hbox{O}_{\rm 2max},$$ then on separate occasions they cycled in 35°C at 60% $$\dot{\hbox{V}}\hbox{O}_{\rm 2max}$$ for 15 min (15max), 45 min with no cooling (NC), and 45 min with fan airflow (FAN) beginning at ∼18 min into exercise, and each bout was immediately followed by a GXT to measure $$\dot{\hbox{V}}\hbox{O}_{\rm 2max}. $$ In NC, $$ \dot{\hbox{V}}\hbox{O}_{\rm 2max} $$ decreased 18%, heart rate (HR) increased 16%, and stroke volume (SV) fell 12% (P < 0.05) from min 15 to min 45. In FAN, $$\dot{\hbox{V}}\hbox{O}_{\rm 2max}$$ fell less (5.7%, P < 0.05) , HR rose less (4%, P < 0.05) and SV decreased less (3%, P < 0.05) from 15 to 45 min. The fall in $$\dot{\hbox{V}}\hbox{O}_{\rm 2max}$$ associated with CV drift during exercise in a hot environment is attenuated with body cooling via fan airflow. The findings support the notion that a causal link exists between CV drift that occurs during prolonged exercise in a hot environment and a decrease in $$\dot{\hbox{V}}\hbox{O}_{\rm 2max}.$$
Unemployment, Imperfect Risk Sharing, and the Monetary Business Cycle

This paper examines the impact of unemployment insurance on the propagation of monetary disturbances in a staggered price model of the business cycle. To motivate a role for risk sharing behavior, I construct a quantitative equilibrium model that gives prominence to an e‐ciency-wage theory of unemployment based on imperfectly observable labor efiort. Dynamic simulations reveal that under a full insurance arrangement, staggered price-setting is incapable of generating persistent real efiects of a monetary shock. Introducing partial insurance, however, bolsters the amount of endogenous wage rigidity present in the model, enriching the propagation mechanism. Positive real persistence appears in versions of the model that exclude capital accumulation as well as in versions that do not.
Infinite Grassmannians and moduli spaces of G-bundles

Let C be a smooth projective irreducible algebraic curve over C of any genus and G a connected simply-connected simple affine algebraic group over C. In this paper we elucidate the relationship between (1) the space of vacua ("conformal blocks") defined in conformal field theory, using an integrable highest weight representation of the affine Kac-Moody algebra associated to G and (2) the space of regular sections ("generalised theta functions") of a line bundle on the moduli space TA of semistable principal G-bundles on C. Fix a point p in C and let ~p (resp. kp) be the completion of the local ring #p of C at p (resp. the quotient field of C~p). Let ;~ := G(kp) (the kp-rational points of the algebraic group G) be the loop group of G and let ;~ := G(#~p) be the standard maximal parahoric subgroup of ~:. Then the generalised flag variety X := N / . ~ is an inductive limit of projective varieties, in fact of generalised Schubert varieties. One has a natural .~r line bundle s on X (cf. Sect. 2.2), and the Picard group Pic(X) is isomorphic to Z which is generated by s (Proposition 2.3), where ,~f is the universal central extension of .%: by the multiplicative group C* (cf. Sect. 2.2). By an analogue of the Borel-Weil theorem proved in the Kac-Moody setting by Kumar (and also by Mathieu), the space H~162 s of the regular sections of the line bundle Y-(dxo) := Y-(Xo) | (for any d = 0) is canonically isomorphic with the full vector space dual V(dXo)* of the (integrable) highest weight (irreducible) module V(dXo) of the affine KacMoody group .~ (or of the associated affine Kac-Moody algebra, which is a certain one dimensional central extension of the loop algebra (Lie G) | with highest weight dXo (cf. Sect. 6.1).
Deformation of algebras over the Landweber–Novikov algebra

Abstract An algebraic deformation theory of algebras over the Landweber–Novikov algebra is obtained.
Wave-field extrapolation by the linearly transformed wave equation

Many approximations to different order of the one‐way scalar wave equation have been suggested in seismic imaging or modeling. Of these approximations, the first‐order approximation, usually called the 15‐degree equation, is most commonly used in industry because of its high efficiency. However, one common constraint of all these approximations is that they cannot handle large‐angle events exactly. Through a linear transformation of the wave equation, the LInearly Transformed Wave EQuation (LITWEQ) is obtainable, without approximation. The LITWEQ has the form of the 15‐degree equation. The solution to the LITWEQ is still a two‐way wave solution. By imposing the boundary condition for upcoming (or downgoing) waves, the LITWEQ can be applied to seismic imaging (or modeling). Implementing the LITWEQ with a finite‐differencing algorithm gives a 180‐degree, or all‐dip, finite‐difference wave‐extrapolation operator, which solves the angle limitation problem of conventional finite‐difference methods.
Validity of using methanol for studying the microstructure of cement paste

Experiments were conducted to assess the extent of interaction of methanol with calcium hydroxide at 22°C. The following techniques were used: X-ray diffraction, infrared spectroscopy, surface-area determination, length change, calorimetry, differential thermal analysis and thermogravimetric analysis. It was concluded that either calcium methoxide or a methylated complex is formed when calcium hydroxide is mixed with methanol.
PP-wave string interactions from perturbative Yang-Mills theory

Recently, Berenstein et al. have proposed a duality between a sector of = 4 super-Yang-Mills theory with large R-charge J, and string theory in a pp-wave background. In the limit considered, the effective 't Hooft coupling has been argued to be ?' = gYM2N/J2 = 1/(?p+?')2. We study Yang-Mills theory at small ?' (large ?) with a view to reproducing string interactions. We demonstrate that the effective genus counting parameter of the Yang-Mills theory is g22 = J4/N2 = (4?gs)2(?p+?')4, the effective two-dimensional Newton constant for strings propagating on the pp-wave background. We identify g2(?')1/2 as the effective coupling between a wide class of excited string states on the pp-wave background. We compute the anomalous dimensions of BMN operators at first order in g22 and ?' and interpret our result as the genus one mass renormalization of the corresponding string state. We postulate a relation between the three-string vertex function and the gauge theory three-point function and compare our proposal to string field theory. We utilize this proposal, together with quantum mechanical perturbation theory, to recompute the genus one energy shift of string states, and find precise agreement with our gauge theory computation.
Rhetorical functions of hashtag forms across social media applications

This study examines an ethnographically-collected set of social media posts from 5 applications in order to understand the rhetorical functions of something we call "metacommunicative" hashtags (e.g., #PackersGottaWinThisOne, #thisweddingisawesome). Through a process of inductive analysis, we identified recurring genre functions that are both context-specific to applications' ecologies and, at the same time, "stabilized enough" (Schryer, 1993, p. 204) to warrant the use of rhetorical genre theory as a tool for understanding their communicative purposes
NONPARAMETRIC ESTIMATION OF A GENERALIZED ADDITIVE MODEL WITH AN UNKNOWN LINK FUNCTION

mean of a random scalar Y conditional on a random vector X E Rd. Let H(x) E(YIX = x) denote the conditional mean function. This paper is concerned with estimating H under weak assumptions about its functional form when X is a multidimensional, continuous random variable. The paper describes a model that nests single-index, additive, and multiplicative models and that can be estimated with a faster rate of convergence in probability than can a fully nonparametric model. Nonparametric estimation of H is usually unattractive when X is multidimensional. The rate of convergence of nonparametric estimators decreases rapidly as the dimension of X increases, and nonparametric estimates can be very imprecise with samples of practical size when X is multidimensional (the curse of dimensionality). This problem can be overcome through the use of dimension-reduction methods. They reduce the effective dimension of the estimation problem by making assumptions about the functional form of H that are stronger than those of a fully nonparametric estimator but weaker than those of a finite-dimensional parametric model. One method of dimension reduction is semiparametric single-index modeling. The best known and most easily estimated semiparametric single-index model assumes that (1.1) H(x) = G( 3'x), where ,3 is an unknown d x 1 vector and G is an unknown function. The vector /3 can be estimated with an n - 1/2 rate of convergence in probability, which is the rate that would be obtained if G were known (Han (1987), Hardle and Stoker (1989), Horowitz and Hardle (1996), Ichimura (1993), Klein and Spady (1993), Newey and Stoker (1993), Powell, Stock, and Stoker (1989), Sherman (1993), Stoker (1991)). G can be estimated with the rate of convergence n -r/(2r+ 1), where r is an integer that depends on the smoothness of G but not on d. Dimension reduction can also be achieved by using a nonparametric generalized additive model. In such a model,
Convection effects on radial segregation and crystal–melt interface in vertical Bridgman growth

We analytically study the influence of convection caused by horizontal heat transfer through the sides of a vertical Bridgman apparatus. We consider the case when the heat transfer across the side walls is small so that the resulting interfacial deformation and fluid velocities are also small. This allows us to linearize the Navier-Stokes equations and express the interfacial conditions about a planar interface through a Taylor expansion. Using a no tangential stress conditions on the side walls, asymptotic expressions for both the interfacial slope, and radial segregation at the crystal-melt interface are obtained in closed form in the limit of large thermal Rayleigh number. It is suggested that these can be reduced by appropriately controlling a specific heat transfer property at the edge of the insulation zone in the solid side.
Size distribution modeling for fluidized bed solar-grade silicon production☆

This work addresses modeling size distribution of solar-grade silicon particles grown by thermal decomposition of silane gas in a fluidized bed reactor. Particles grow with heterogeneous chemical vapor deposition and by scavenging powder produced in homogeneous gas phase reaction. The model uses ordinary differential and algebraic equations that track particle movement through discrete size intervals to simulate changes in the size distribution. The model solves quickly and is easily tuned to fit experimental data. Validating the model with experimental data from pilot plant tests shows that this approach is useful for control system design and scale-up of the fluidized bed silicon production process. Combining the developed model with feedback control theory also provides a novel method for sensitivity analysis.
Reverse Mortgages and Borrower Maintenance Risk

This paper develops a theoretical model of the problem of maintenance risk in reverse mortgages (RMs) and home equity conversion instruments generally. By maintenance risk, we refer to the incentive homeowners will have to reduce maintenance expenditures as their equity in the house falls during the term of the RM. The underlying reason for this tendency is the limited liability feature of RMs, given that a borrower's obligation to the lender at. maturity is limited to the value of the house. The results of the model show that lenders will respond to this problem either by limiting the amount of RM loans to guarantee that maintenance risk is not a threat, or by charging an interest rate premium to cover the expected cost of default. Unfortunately, there do not exist data to test the importance of maintenance risk as a possible limitation on the extent of the RM market.
Non-perturbative K3 orientifolds with NS–NS B-flux

Abstract We consider non-perturbative six dimensional N =1 space-time supersymmetric orientifolds of Type IIB on K3 with non-trivial NS–NS B -flux. All of these models are non-perturbative in both orientifold and heterotic pictures. Thus, some states in such compactifications arise in “twisted” open string sectors which lack world-sheet description in terms of D-branes. We also discuss their dual F-theory compactifications on certain Voisin–Borcea orbifolds. In particular, the explicit construction of non-perturbative K3 orientifolds with NS–NS B -flux gives additional evidence for the conjectured extension of Nikulin's classification in the context of Voisin–Borcea orbifolds.
How galaxies form: Mass assembly from chemical abundances in the era of large surveys

The chemical abundances in the atmosphere of a star provide unique information about the gas from which that star formed, and, modulo processes that are not important for the vast majority of stars, such as mass transfer in close binary systems, are conserved through a star's life. Correlations between chemistry and kinematics have been used for decades to trace dynamical evolution of the Milky Way Galaxy. I discuss how it should be possible to refine and extend such analyses, provided planned large-scale deep imaging surveys have matched spectroscopic surveys.
The Mass of the Central Black Hole in the Seyfert Galaxy NGC 3783

Improved analysis of ultraviolet and optical monitoring data on the Seyfert 1 galaxy NGC 3783 provides evidence for the existence of a supermassive, (8.7 +/- 1.1) x 10(exp 6) solar mass, black hole in this galaxy. By using recalibrated spectra from the International Ultraviolet Explorer satellite and ground-based optical data, as well as refined techniques of reverberation mapping analysis, we have reduced the statistical uncertainties in the response of the emission lines to variations in the ionizing continuum. The different time lags in the emission-line responses indicate a stratification in the ionization structure of the broad-line region and are consistent with the virial relationship suggested by the analysis of similar active galaxies.
The Road Taken: Origins and Evolution of Employment Systems in Emerging Companies

Excerpt] Drawing on a unique archive of qualitative and quantitative data describing 100 Bay Area high technology firms within their first decade, this paper examines the models of employment relations espoused by company founders and bow those models shaped the evolution of human resource management within their organizations. Information gleaned from interviews suggests that founders and others involved in designing and launching these companies had blueprints for the employment relation that varied along three key dimensions: the primary basis of employee attachment and motivation, the primary means for controlling and coordinating work, and the primary criterion emphasized in selection. Based on combinations of these three dimensions, firms in our sample cluster fall into one of four distinct types, which we label the star, factory, engineering, and commitment models. Multivariate statistical analyses document how the founder's employment model shaped the subsequent adoption and timing of various human resource policies and documents over these companies' early histories, as well as the speed with which the first full-time human resource manager was appointed The findings are strongly suggestive of complementarities and a tendency toward internal consistency among dimensions of human resource management, and of strong path dependence in the evolution of employment systems in organizations. Some implications of these findings for transactions cost perspectives on the employment relationship are discussed.
Everlasting Secrecy by Exploiting Non-Idealities of the Eavesdropper's Receiver

Secure communication over a memoryless wiretap channel in the presence of a passive eavesdropper is considered. Traditional information-theoretic security methods require an advantage for the main channel over the eavesdropper channel to achieve a positive secrecy rate, which in general cannot be guaranteed in wireless systems. Here, we exploit the non-linear conversion operation in the eavesdropper's receiver to obtain the desired advantage - even when the eavesdropper has perfect access to the transmitted signal at the input to their receiver. The basic idea is to employ an ephemeral cryptographic key to force the eavesdropper to conduct two operations, at least one of which is non-linear, in a different order than the desired recipient. Since non-linear operations are not necessarily commutative, the desired advantage can be obtained and information-theoretic secrecy achieved even if the eavesdropper is given the cryptographic key immediately upon transmission completion. In essence, the lack of knowledge of the key during the short transmission time inhibits the recording of the signal in such a way that the secret information can never be extracted from it. The achievable secrecy rates for different countermeasures that the eavesdropper might employ are evaluated. It is shown that even in the case of an eavesdropper with uniformly better conditions (channel and receiver quality) than the intended recipient, a positive secrecy rate can be achieved.
Is obesity a public health problem

It is often claimed that there is an obesity epidemic in affluent countries, and that obesity is one of the most serious public health problems in the developed world. I will argue that obesity is not an ‘epidemic’ in any useful sense of the word, and that classifying it as a public health problem requires us to make fairly controversial moral and empirical assumptions. While epidemiological evidence suggests that the prevalence of obesity is on the rise and can lead to serious health problems ranging from diabetes to cardiovascular disease, this does not by itself show that obesity is a public health problem.
Geologic mapping of the Zal region of Io

Abstract We produced a regional geologic map of the Zal region of Io's antijovian hemisphere using Galileo mission data. We discuss the geologic features, summarize the map units and structures that are present, discuss the nature of volcanic activity, and present an analysis of the volcanic, tectonic, and gradational processes that affect the region. The Zal region consists of five primary types of geologic materials: plains, mountains, paterae floors, flows, and diffuse deposits. The flows and patera floors are similar, but are subdivided based on uncertainties regarding emplacement environments and mechanisms. The Zal region includes two hotspots detected by Galileo : one along the western scarp of the Zal Patera volcano and one at the Rustam Patera volcano (name submitted to IAU). A third hotspot at the nearby At'am Patera volcano (name submitted to IAU) is the source of diffuse and pyroclastic materials that blanket north Zal Mons. The western bounding scarp of Zal Patera is the location of a fissure vent that is the source of multiple silicate lava flows. The floor of Zal Patera has been partially resurfaced by dark lava flows, although portions of the patera floor appear bright and unchanged during the Galileo mission. This suggests that the floor did not undergo complete resurfacing as a flooding lava lake but does contain a compound flow field. Mountain materials exhibit stages of degradation; lineated material degrades into mottled material. We have explored the possibility that north and south Zal Mons were originally one structure. We propose that strike-slip faulting and subsequent rifting separated the mountain units, opened a fissure which serves as a vent for lava flow, and created a depression which, by further extension during the rifting event, became Zal Patera. With comparison to other regional maps of Io, this work provides insight into the general geologic evolution of Io.
Pure virtual braids homotopic to the identity braid

Two virtual link diagrams are homotopic if one may be transformed into the other by a sequence of virtual Reidemeister moves, classical Reidemeister moves, and self crossing changes. We recall the pure virtual braid group. We then describe the set of pure virtual braids that are homotopic to the identity braid.