cssi/SciSciGPT-SciSciNet huggingface dataset:
Black Residential Centralization and the Spatial Mismatch Hypothesis

Abstract Black residential centralization is found to be an important determinant of black employment status when estimated across metropolitan areas (MAs) to avoid neighborhood selection. The effects are greatest in large MAs, for the young and elderly, and for individuals with less than a college education. Instrumental variable (IV) estimates support ordinary least squares (OLS) results. Black residential centralization can account for 48–62% of the black–white employment differential among 18–30 year olds living in large MAs. When estimated together, black residential centralization, job centralization, and segregation all have large effects, but the effects of black centralization and job centralization are considerably larger.
An examination of large sell orders in cold IPO aftermarkets

Abstract It is well-known that investment banks routinely take large naked short positions for low demand IPOs, and for such cold IPOs, the immediate sale of initial allocations back to the market accounts for a relatively large proportion of total trading volume. In this paper, we investigate the relationship between investment banks and institutional investors during the stabilization period. Specifically, we hypothesize that lead underwriters cover their short positions through selective share buy-back from institutional investors at the offer price. Using trade data, we examine the trading patterns of large (institutional) and small (retail) trades during the stabilization period. We find that a large proportion of institutional sells take place at the offer price, while a large proportion of retail sells take place below the offer price in a cold IPO stabilization period. We then estimate the information content of all trades to determine whether seller-initiated trades from institutional investors are correctly anticipated by the investment bank in an effort to cover their short position. If they are anticipated, these trades would carry little to no new information. Indeed, we find that the information content of large sell orders in cold IPO aftermarkets is lower than the information content of small trades, and is the least compared to several control samples. The results are robust and survive controls for external factors such as volume, turnover, and volatility. These results suggest that lead underwriters allow their valuable buy-side clients to sell back cold IPO allocations at the offer price.
Mice lacking epidermal PPARγ exhibit a marked augmentation in photocarcinogenesis associated with increased UVB-induced apoptosis, inflammation and barrier dysfunction

Recent studies suggest that peroxisome proliferator-activated receptor gamma (PPARγ) agonists may have cancer chemopreventive activity. Other studies have shown that loss of epidermal PPARγ results in enhanced chemical carcinogenesis in mice via unknown mechanisms. However, ultraviolet B (UVB) exposure represents the primary etiological agent for skin cancer formation and the role of PPARγ in photobiology and photocarcinogenesis is unknown. In previous studies, we demonstrated that UVB irradiation of cells results in the formation of oxidized glycerophosphocholines that exhibit PPARγ ligand activity. We therefore hypothesized that PPARγ would prove to be a chemopreventive target in photocarcinogenesis. We first showed that UVB irradiation of mouse skin causes generation of PPARγ agonist species in vivo. We then generated SKH-1 hairless, albino mice deficient in epidermal Pparg (Pparg-/-(epi)) using a cytokeratin 14 driven Cre-LoxP strategy. Using a chronic model of UVB photocarcinogenesis, we next showed that Pparg-/-(epi) mice exhibit an earlier onset of tumor formation, increased tumor burden and tumor progression. Increased tumor burden in Pparg-/-(epi) mice was accompanied by a significant increase in epidermal hyperplasia and p53 positive epidermal cells in surrounding skin lacking tumors. After acute UVB irradiation, Pparg-/-(epi) mice exhibited an augmentation of both UVB-induced Caspase 3/7 activity and inflammation. Increased apoptosis and inflammation was also observed after treatment with the PPARγ antagonist GW9662. With chronic UVB irradiation, Pparg-/-(epi) mice exhibited a sustained increase in erythema and transepidermal water loss relative to wildtype littermates. This suggests that PPARγ agonists could have possible chemopreventive activity in non-melanoma skin cancer.
Direct free-radical substitutions on allyl and vinyl halides using alkyl halides/hexabutylditin

Abstract Allyl and vinyl halides are excellent acceptors for tin-mediated substitutions by alkyl radicals generated from alkyl halides.
Using the local density approximation and the LYP, BLYP and B3LYP functionals within reference-state one-particle density-matrix theory

For closed-shell systems, the local density approximation (LDA) and the LYP, BLYP and B3LYP functionals are shown to be compatible with reference-state one-particle density-matrix theory, where this recently introduced formalism is based on Brueckner-orbital theory and an energy functional that includes exact exchange and a non-universal correlation-energy functional. The method is demonstrated to reduce to a density functional theory when the exchange-correlation energy-functional has a simplified form, i.e. its integrand contains only the coordinates of two electrons, say r 1 and r 2, and it has a Dirac delta function δ(r 1 - r 2 as a factor. Since Brueckner and Hartree–Fock orbitals are often very similar, any local exchange functional that works well with Hartree–Fock theory is a reasonable approximation with reference-state one-particle density-matrix theory. The LDA approximation is also a reasonable approximation. However, the Colle–Salvetti correlation-energy functional and the LYP variant are not...
3-Manifolds with nonnegative Ricci curvature

For a complete noncompact 3-manifold with nonnegative Ricci curvature, we prove that either it is diffeomorphic to ℝ3 or the universal cover splits. This confirms Milnor’s conjecture in dimension 3.
Layered ruthenium hexagonal perovskites: The new series [Ba2Br2−2x(CO3)x][Ban+1RunO3n+3] with n=2, 3, 4, 5

Single crystals of the title compounds were prepared by solid state reactions from barium carbonate and ruthenium metal using a BaBr{sub 2} flux and investigated by X-ray diffraction method using Mo(K{alpha}) radiation and a Charge Coupled Device (CCD) detector. A structural model for the term n=2, Ba{sub 5}Ru{sub 2}Br{sub 2}O{sub 9} (1) was established in the hexagonal symmetry, space group P6{sub 3}/mmc, a=5.8344(2)A, c=25.637(2)A, Z=2. Combined refinement and maximum-entropy method (MEM) unambiguously show the presence of CO{sub 3}{sup 2-} ions in the three other compounds (2, 3, 4). Their crystal structures were solved and refined in the trigonal symmetry, space group P3-barml, a=5.8381(1)A, c=15.3083(6)A for the term n=3, Ba{sub 6}Ru{sub 3}Br{sub 1.54}(CO{sub 3}){sub 0.23}O{sub 12} (2), and space group R3-barm, a=5.7992(1)A, c=52.866(2)A and a=5.7900(1)A, c=59.819(2)A for the terms n=4, Ba{sub 7}Ru{sub 4}Br{sub 1.46}(CO{sub 3}){sub 0.27}O{sub 15} (3), and n=5, Ba{sub 8}Ru{sub 5}Br{sub 1.64}(CO{sub 3}){sub 0.18}O{sub 18} (4), respectively. The structures are formed by the periodic stacking along [001] of (n+1) hexagonal close-packed [BaO{sub 3}] layers separated by a double layer of composition [Ba{sub 2}Br{sub 2-2x}(CO{sub 3}){sub x}]. The ruthenium atoms occupy the n octahedral interstices created in the hexagonal perovskite slabs and constitute isolated dimers Ru{sub 2}O{sub 9} of face-sharedmore » octahedra (FSO) in 1 and isolated trimers Ru{sub 3}O{sub 12} of FSO in 2. In 3 and 4, the Ru{sub 2}O{sub 9} units are connected by corners either directly (3) or through a slab of isolated RuO{sub 6} octahedra (4) to form a bidimensional arrangement of RuO{sub 6} octahedra. These four oxybromocarbonates belong to the family of compounds formulated [Ba{sub 2}Br{sub 2-2x}(CO{sub 3}){sub x}][Ba{sub n+1}Ru{sub n}O{sub 3n+3}] where n represents the thickness of the octahedral string in hexagonal perovskite slabs. These compounds are compared to the oxychloride series.« less
Anti-hydroalumination of Homo- and bishomopropargyl alcohols

The reaction of ω-Me3Si- or ω-Me3Ge-substituted 3-butyn-1-ol, 4-pentyn-1-ol, and their derivatives with DIBAL-H and a small trialkylalane, e.g., Me3Al or Et3Al, at 23 °C gives, after iodinolysis, the corresponding (Z)-4-iodo-3-buten-1-ols and (Z)-5-iodo-4-penten-1-ols in a highly stereo- and regio-selective manner, most probably via endo-dig mode cyclic anti-hydroalumination, while treatment of ω-carbosubstituted 3-butyn-1-ols with Red-Al or LiAlH4 at high temperatures followed by iodinolysis can give the corresponding (Z)-4-iodo-3-buten-1-ols also in a highly regio- and stereoselective manner.
Light front theory of nuclear matter

Abstract A relativistic light front formulation of nuclear dynamics is applied to infinite nuclear matter. A hadronic meson-baryon Lagrangian, consistent with chiral symmetry, leads to a nuclear eigenvalue problem which is solved, including nucleon-nucleon NN correlations, in the one-boson-exchange approximation for the NN potential. The nuclear matter saturation properties are reasonably well reproduced, with a compression modulus of 180 MeV. We find that there are ≈0.05 excess pions per nucleon.
Charge ratio of muons from atmospheric neutrinos

We calculate the intensities and angular distributions of positive and negative muons produced by atmospheric neutrinos. We comment on some sources of uncertainty in the charge ratio. We also draw attention to a potentially interesting signature of neutrino oscillations in the muon charge ratio, and we discuss the prospects for its observation (which are not quite within the reach of currently planned magnetized detectors).
Infection with the human immunodeficiency virus type 2.

Purpose: To review the clinical, epidemiologic, and biological features of infection with the human immunodeficiency virus type 2 (HIV-2). Data Identification: Studies published since 1981 identifi...
Positron Escape from Type Ia Supernovae

We generate bolometric light curves for a variety of Type Ia supernova models at late times, simulating gamma-ray and positron transport for various assumptions about the magnetic field and ionization of the ejecta. These calculated light curve shapes are compared with light curves of specific supernovae for which there have been adequate late observations. The selection of models is generally not based upon the ability to fit the late observations, but rather because the model has been demonstrated by other authors to approximate the spectra and early light curves of that specific SN. From these comparisons we draw two conclusions: whether a suggested model is an acceptable approximation of a particular event, and, given that it is, the magnetic field characteristics and degree of ionization that are most consistent with the observed light curve shape. For the 10 SNe included in this study, five strongly suggest 56Co positron escape as would be permitted by a weak or radially combed magnetic field. Of the remaining five SNe, none clearly show the upturned light curve expected for positron trapping in a strong, tangled magnetic field. Chandrasekhar mass models can explain normally luminous, slightly subluminous, and superluminous supernova light curves; sub-Chandrasekhar mass models have difficulties with subluminous SNe. An estimate of the galactic positron production rate from Type Ia SNe is compared with gamma-ray observations of Galactic 511 keV annihilation radiation. Additionally, we emphasize the importance of correctly treating the positron transport for calculations of spectra, or any properties, of Type Ia SNe at late epochs (≥200 days).
A SIMPLE DIRAC WAVE FUNCTION FOR A COULOMB POTENTIAL WITH LINEAR CONFINEMENT

A simple analytical solution is found to the Dirac equation for the combination of a Coulomb potential with a linear confining potential. An appropriate linear combination of Lorentz scalar and vector linear potentials, with the scalar part dominating, can be chosen to give a simple Dirac wave function. The binding energy depends only on the Coulomb strength and is not affected by the linear potential. The method works for the ground state, or for the lowest state with l=j-1/2, for any j.
Nonlinear propagation of a wave packet in a hard-walled circular duct

The method of multiple scales is used to derive a nonlinear Schroedinger equation for the temporal and spatial modulation of the amplitudes and the phases of waves propagating in a hard-walled circular duct. This equation is used to show that monochromatic waves are stable and to determine the amplitude dependance of the cut off frequencies.
Neutrino-nucleus interaction and supernova r-process nucleosynthesis

Abstract We discuss various neutrino-nucleus interactions in connection with the supernova r-process nucleosynthesis, which possibly occurs in the neutrino-driven wind of a young neutron star. These interactions include νe and ν e absorptions on free nucleons, νe captures on neutron-rich nuclei, and neutral-current νμ(τ) and ν μ(τ) interactions with α-particles and neutron-rich nuclei. We describe how these interactions can affect the r-process nucleosynthesis and discuss the implications of their effects for the physical conditions leading to a successful supernova r-process. We conclude that a low electron fraction and/or a short dynamic time scale may be required to give the sufficient neutron-to-seed ratio for an r-process in the neutrino-driven wind. In the case of a short dynamic time scale, the wind has to be contained during the r-process. Possible mechanisms which can give a low electron fraction or contain the wind are discussed.
MODELING ECOLOGICAL CONSTRAINTS ON TROPICAL FOREST MANAGEMENT: COMMENT

Abstract We offer this comment on 1 recent model of ecological constraints on tropical forest management in order to emphasize the complexity of the subject and to qualify the usefulness of her method. Albers structures her model in a highly asymmetric manner in favor of preservation. We contend that the results of a truly general, empirically defensible model of tropical forest management are inherently ambiguous. Spatial and intertemporal dimensions clearly matter, but they do not point as neatly in favor of preservation as Albers would have us believe.
Experimental demonstration of associative memory with memristive neural networks

Synapses are essential elements for computation and information storage in both real and artificial neural systems. An artificial synapse needs to remember its past dynamical history, store a continuous set of states, and be ''plastic'' according to the pre-synaptic and post-synaptic neuronal activity. Here we show that all this can be accomplished by a memory-resistor (memristor for short). In particular, by using simple and inexpensive off-the-shelf components we have built a memristor emulator which realizes all required synaptic properties. Most importantly, we have demonstrated experimentally the formation of associative memory in a simple neural network consisting of three electronic neurons connected by two memristor-emulator synapses. This experimental demonstration opens up new possibilities in the understanding of neural processes using memory devices, an important step forward to reproduce complex learning, adaptive and spontaneous behavior with electronic neural networks.
Numerical analysis of a high-velocity oxygen-fuel thermal spray system

The fluid and particle flow field characteristics of a high-velocity oxygen-fuel (HVOF) thermal spray (TS) system are analyzed using a two-phase flow model and simulated using computational fluid dynamics (CFD) techniques. The model consists of a conservation equation and constitutive relations for both gas and particle phases. Compressible, turbulent flow is modeled by ak-ɛ turbulent model. A Lagrangian formulation is used to model particle trajectory, and heat and momentum transfer. The fluid velocity fluctuations resulting from gas turbulence are simulated by a stochastic model and the particle motion in the turbulent flow is calculated in a Lagrangian Stochastic-Deterministic (LSD) method. Details of gas flow field, particle temperature and particle velocity histories, and particle temperature and velocity profiles in the system are presented. For the validation of the numerical analysis, the computed results are compared with available experimental measurement. Excellent agreement between simulations and measurements is obtained for both gas and particle flow fields. A parametric study is also conducted for different particle sizes and different nozzle barrel lengths. The flow phenomena for different flow parameters are analyzed and explained as the result of gas dynamics and heat and momentum transfer between the two phases. The developed methodology provides a means to analyze, design, and optimize the TS process. The numerical analysis presents a first comprehensive, fundamental quantitative analysis for the HVOF TS system.
On-orbit Absolute Blackbody Emissivity Determination Using the Heated Halo Method

The Heated Halo method can be used to accurately measure the spectral emissivity of a blackbody, on-orbit, using a broadband thermal source.
Inertial attitude determination for a dual-spin planetary spacecraft

Design and performance evaluations of an onboard inertial attitude determination system for a dual-spin planetary spacecraft are presented. A quaternion integration algorithm and a rate estimator sequentially determine the scan platform's inertial attitude and rate from the drift and misalignment compensated gyro outputs. A least-squares estimator algorithm processes the star transit data from a rotor-mounted star scanner, and provides periodic updates of the scan platform's attitude as a means of correcting the drift of the quaternion integration algorithm. Computer simulated algorithm performance in the presence of nutation and sensor noise are presented.
A NEW STRUCTURAL FORM OF TIN IN AN OXYGEN-CAPPED CLUSTER

Abstract Recently we have shown that oligomeric organotin oxycarboxylates based on the compositions [R'Sn(O)O2CR]6 and [(R'Sn(O)O2CR)2R'Sn(O2CR)3]2 have “drum” 1-3 and “ladder”2,3 structures, respectively. Reaction of n-butylstannoic acid with diphenylphosphonic acid instead of a carboxylic acid results in the for- mation of an analogous drum composition, [n-BuSn(O)O2P(OPh)2]6.4 However, when diphenylphosphinic acid is reacted with n-butylstannoic acid under reflux in toluene, a new structural form of tin is obtained. This report concerns the synthesis and structural characterization of this novel substance.
Deep Start: a hybrid strategy for automated performance problem searches

We present Deep Start, a new algorithm for automated performance diagnosis that uses stack sampling to augment our search-based automated performance diagnosis strategy. Our hybrid approach locates performance problems more quickly and finds problems hidden from a more straightforward search strategy. Deep Start uses stack samples collected as a by-product of normal search instrumentation to find deep starters, functions that are likely to be application bottlenecks. Deep starters are examined early during a search to improve the likelihood of finding performance problems quickly. We implemented the Deep Start algorithm in the Performance Consultant, Paradyn's automated bottleneck detection component. Deep Start found half of our test applications' known bottlenecks 32% to 59% faster than the Performance Consultant's current call graphbased search strategy, and finished finding bottlenecks 10% to 61% faster. In addition to improving search time, Deep Start often found more bottlenecks than the call graph search strategy.
Thermoelectric performance of weakly coupled granular materials

We study thermoelectric properties of inhomogeneous nanogranular materials for weak tunneling conductance between the grains, gt<1. We calculate the thermopower and figure of merit taking into account the shift of the chemical potential and the asymmetry of the density of states in the vicinity of the Fermi surface. We show that the weak coupling between the grains leads to a high thermopower and low thermal conductivity resulting in relatively high values of the figure of merit on the order of one. We estimate the temperature at which the figure of merit has its maximum value for two- and three-dimensional samples. Our results are applicable for many emerging materials, including artificially self-assembled nanoparticle arrays.
Piezo-electric activity of Rochelle salt under various conditions

Electrical Properties of Rochelle Salt Crystal are analogous to the magnetic properties of iron, the dielectric displacement $D$ and polarization $P$ varying with the electric field $E$ in the same general manner as $B$ and $I$ vary with $H$ for iron, and showing an electric hysteresis with loops distorted by an amount corresponding to the permanent polarization ${P}_{0}$, whose value is about 30 e.s.u./${\mathrm{cm}.}^{3}$ but varies for different crystals. The dielectric constant ($\ensuremath{\kappa}=\frac{\mathrm{dD}}{\mathrm{dE}}$) was measured from --- 70\ifmmode^\circ\else\textdegree\fi{} to 30\ifmmode^\circ\else\textdegree\fi{} $C$. and found to be surprisingly large, increasing from about 50 at --- 70\ifmmode^\circ\else\textdegree\fi{} to a maximum of about 1,000 near 0\ifmmode^\circ\else\textdegree\fi{}. The modulus of piezo-electric activity for shearing stresses ($\ensuremath{\delta}$) varies with temperature, --- 70\ifmmode^\circ\else\textdegree\fi{} to 40\ifmmode^\circ\else\textdegree\fi{} $C$., in a very similar manner, increasing from less than ${10}^{\ensuremath{-}6}$ at --- 70\ifmmode^\circ\else\textdegree\fi{} to a maximum of about ${10}^{\ensuremath{-}4}$ at 0\ifmmode^\circ\else\textdegree\fi{}. The ratio $\frac{\ensuremath{\delta}}{\ensuremath{\kappa}}$ varied with the electrode material, being greater for tin foil than for mercury electrodes. The difference may be due to the alcohol used in shellacking the tin-foil electrodes on. There are other indications that $\ensuremath{\delta}$ and $\ensuremath{\kappa}$ are related. The variation of $\ensuremath{\delta}$ with humidity is such as can be accounted for by the decrease in the dielectric constant of the outer layer as a result of dehydration. The change of polarization produced by pressure as measured by the change in the hysteresis loop agrees with the value found directly from the piezo-electric response, as required by Lord Kelvin's theory. Also fatigue effects on $\ensuremath{\delta}$ produced by temporarily applied fields are traceable to fatigue in the polarization. The electrical conductivity below 45\ifmmode^\circ\else\textdegree\fi{} is less than 5 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}9}$ mhos/${\mathrm{cm}.}^{3}$ but from 43\ifmmode^\circ\else\textdegree\fi{} to 57\ifmmode^\circ\else\textdegree\fi{} increases rapidly to 5 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}4}$.Optical Properties of Rochelle Salt as Calculated from the Natural Polarization.--- Assuming only one electron is displaced the natural period corresponds to a wavelength of 4.2 \ensuremath{\mu} and the specific rotation for sodium light comes out 10\ifmmode^\circ\else\textdegree\fi{}, the observed value being 22\ifmmode^\circ\else\textdegree\fi{}.1.
Divergent and facile Lewis acid-mediated synthesis of N-alkyl 2-aminomethylene-1,3-indanediones and 2-alkylamino-1,4-naphthoquinones

N-Alkyl 2-aminomethylene-1,3-indanediones and 2-alkylamino-1,4-naphthoquinones are known for their diverse and versatile bioactivities and applications. Traditionally, these two compounds were synthesized in separate routes using different materials. By employing Lewis acid, cycloaddition of alkyl azides and 1,4-naphthoquinone can provide these two classes of compound in one-pot fashion. Among the Lewis acids and conditions examined, TMSOTf under reflux offers the best overall yields. In addition, the purification of both classes of compounds can be easily achieved using flash column chromatography making this methodology feasible for scale-up synthesis of compounds with biological interests.
Interactions between light waves in a nonlinear dielectric

The induced nonlinear electric dipole and higher moments in an atomic system, irradiated simultaneously by two or three light waves, are calculated by quantum-mechanical perturbation theory. Terms quadratic and cubic in the field amplitudes are included. An important permutation symmetry relation for the nonlinear polarizability is derived and its frequency dependence is discussed. The nonlinear microscopic properties are related to an effective macroscopic nonlinear polarization, which may be incorporated into Maxwell's equations for an infinite, homogeneous, anisotropic, nonlinear, dielectric medium. Energy and power relationships are derived for the nonlinear dielectric which correspond to the Manley-Rowe relations in the theory of parametric amplifiers. Explicit solutions are obtained for the coupled amplitude equations, which describe the interaction between a plane light wave and its second harmonic or the interaction between three plane electromagnetic waves, which satisfy the energy relationship ${\ensuremath{\omega}}_{3}={\ensuremath{\omega}}_{1}+{\ensuremath{\omega}}_{2}$, and the approximate momentum relationship ${\mathrm{k}}_{3}={\mathrm{k}}_{1}+{\mathrm{k}}_{2}+\ensuremath{\Delta}\mathrm{k}$. Third-harmonic generation and interaction between more waves is mentioned. Applications of the theory to the dc and microwave Kerr effect, light modulation, harmonic generation, and parametric conversion are discussed.
Laser-guided atoms in hollow-core optical fibers.

We have used optical forces to guide atoms through hollow-core optical fibers. Laser light is launched into the hollow region of a glass capillary fiber and guided by grazing-incidence reflection from the walls. When the laser is detuned 1--30 GHz red of the Rb D2 resonance lines, dipole forces attract atoms to the high-intensity region along the axis and guide them through the fiber. We show that atoms may be guided around bends in the fiber and that in initial experiments the atoms experience up to 18 reflections from the potential walls with minimal loss.
Lexicon Rhetoricae: the narrative theory of Kenneth Burke and its application to marketing

Purpose – The purpose of this article is to propose Lexicon Rhetoricae, the narrative theory of Kenneth Burke from the discipline of literary criticism, as a comprehensive model which helps to explain how symbolism and nonconscious processes influence the consumption experience, and which helps to reconcile the psychology of the consumption experience with the more observable stimuli of the marketing environment.Design/methodology/approach – Lexicon Rhetoricae distinguishes two categories of literary form – symbolic and formal appeal – which describe inputs to the literary experience. A third term, eloquence, categorizes the interaction of symbolic and formal appeals, and describes how robust that experience is.Findings – Lexicon Rhetoricae provides: a mechanism for describing how unobservable internal psychological processes (conscious or nonconscious) might work; a method for coding observable marketer‐controlled inputs to the consumption experience; and a means for demonstrating how the unobservable pr...
Generalized Kac-Moody Lie algebras, free Lie algebras and the structure of the Monster Lie algebra

Abstract It is shown that any generalized Kac-Moody Lie algebra g that has no mutually orthogonal imaginary simple roots can be written as g = u + ⊕ ( g J + h ) ⊕ u −, where g J is a Kac-Moody algebra defined from a symmetrizable Cartan matrix, and u + and u − are subalgebras isomorphic to free Lie algebras over certain g J-modules. The denominator identity for such an algebra g is obtained by using a generalization of Wilt's formula that computes the graded dimension of the free Lie algebra u − and the denominator identity known for the Kac-Moody subalgebra g J . The main result and consequent proof of the denominator identity give a new proof that the radical of a generalized Kac-Moody algebra of the above type is zero. The main result is applied to the Monster Lie algebra m to obtain an elegant decomposition m = u + ⊕ g I2 ⊕ u −. Also included is a detailed discussion of Borcherds' construction of the Monster Lie algebra from a vertex algebra and an elementary proof of Borcherds' theorem relating Lie algebras with “an almost positive definite bilinear form” to generalized Kac-Moody algebras.
Genome-wide identification of Ago2 binding sites from mouse embryonic stem cells with and without mature microRNAs

MicroRNAs (miRNAs) are 19-22-nucleotide noncoding RNAs that post-transcriptionally regulate mRNA targets. We have identified endogenous miRNA binding sites in mouse embryonic stem cells (mESCs), by performing photo-cross-linking immunoprecipitation using antibodies to Argonaute (Ago2) followed by deep sequencing of RNAs (CLIP-seq). We also performed CLIP-seq in Dicer⁻/⁻ mESCs that lack mature miRNAs, allowing us to define whether the association of Ago2 with the identified sites was miRNA dependent. A significantly enriched motif, GCACUU, was identified only in wild-type mESCs in 3' untranslated and coding regions. This motif matches the seed of a miRNA family that constitutes ~68% of the mESC miRNA population. Unexpectedly, a G-rich motif was enriched in sequences cross-linked to Ago2 in both the presence and absence of miRNAs. Expression analysis and reporter assays confirmed that the seed-related motif confers miRNA-directed regulation on host mRNAs and that the G-rich motif can modulate this regulation.
Increasing Sync Rate of Pulse-Coupled Oscillators via Phase Response Function Design: Theory and Application to Wireless Networks

This brief addresses the synchronization rate of weakly connected pulse-coupled oscillators (PCOs). We prove that besides the coupling strength, the phase response function is also a determinant of the synchronization rate. Inspired by the result, we propose to increase the synchronization rate of PCOs by designing the phase response function. This has important significance in the PCO-based clock synchronization of wireless networks. By designing the phase response function, the synchronization rate is increased even under a fixed transmission power. Given that the energy consumption in synchronization is determined by the product of synchronization time and transmission power, the new strategy reduces energy consumption in the clock synchronization. QualNet experiments confirm the theoretical results.
[Ph2Bi−(Ge9)−BiPh2]2-: A Deltahedral Zintl Ion Functionalized by Exo-Bonded Ligands

The title anion was synthesized by a reaction of nido-Ge94-, made from K4Ge9 dissolved in ethylenediamine and 2,2,2-crypt(4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane), with BiPh3. It was structurally characterized in (K-2,2,2-crypt)2[Ge9(BiPh2)2]·en which was crystallized from the solution. The anion is a monocapped square antiprism of Ge9 with two diphenylbismuth ligands exo-bonded to opposite vertexes of the open face of the cluster. This is the first example where covalently exo-bonded ligands are attached to a deltahedral cluster that can exist without them as well.
Enantioselective Organocatalytic Double Michael Addition Reactions

A novel organocatalytic, enantioselective domino double Michael addition reaction of α,β-unsaturated aldehydes with ethyl 4-mercapto-2-butenoate has been developed. The process is promoted by chiral diphenylprolinol TMS ether to give chiral tetrahydrothiophenes in high to excellent levels of enantioselectivities.
Mapping the Schrödinger picture of open quantum dynamics

For systems described by finite matrices, an affine form is developed for the maps that describe evolution of density matrices for a quantum system that interacts with another. This is established directly from the Heisenberg picture. It separates elements that depend only on the dynamics from those that depend on the state of the two systems. While the equivalent linear map is generally not completely positive, the homogeneous part of the affine maps is, and is shown to be composed of multiplication operations that come simply from the Hamiltonian for the larger system. The inhomogeneous part is shown to be zero if and only if the map does not increase the trace of the square of any density matrix. Properties are worked out in detail for two-qubit examples.
Ring Expansions of Vinyloxiranes, -thiiranes, and -aziridines: Synthetic Approaches, Challenges, and Catalytic Success Stories

Ring expansion reactions of strained vinylic heterocyclic substrates have attracted the attention of the synthetic community for decades. Strategic manipulations of these organic architectures enable access to many useful synthetic intermediates. This paper highlights various methods for the ring expansion of vinyloxiranes, -thiiranes, and -aziridines described in the literature from 1964 to 2013.
Anomalous magnetic and electric dipole moments of the tau

Abstract This paper reviews the theoretical predictions for and the experimental measurements of the anomalous magnetic and electric dipole moments of the tau lepton. In particular, recent analyses of the e+e− → τ+τ−γ process from the L3 and OPAL collaborations are described. The most precise results, from L3, for the anomalous magnetic and electric dipole moments respectively are: aτ = 0.004 ± 0.027 ± 0.023 and dτ = (0.0 ± 1.5 ± 1.3) × 10−16e·cm.
Properties of Relativistic Jets in Gamma-Ray Burst Afterglows

We extend our calculation of physical parameters of gamma-ray burst (GRB) jets by modeling the broadband emission of the afterglows 970508, 980519, 991208, 000926, 000418, and 010222. Together with 990123, 990510, 991216, and 000301c, there are 10 well-observed afterglows for which the initial opening angle of the GRB jet can be constrained. The jet energies (after the GRB phase) obtained for this set of afterglows are within one decade around 5 × 1050 ergs. With the exception of 000418, which requires a jet wider than rad, the jet initial half-angle in the other cases ranges from 2? to 20?. We find that in half of the cases, a homogeneous ambient medium accommodates the afterglow emission better than the windlike r-2 profile medium expected around massive stars. The two types of media give fits of comparable quality in four cases, with a wind medium providing a better description only for 970508. The circumburst densities we obtain are in the 0.1-100 cm-3 range, with the exception of 990123, for which it is below 10-2 cm-3. If in all 10 cases the observed GRB durations are a good measure of the ejecta deceleration timescale, then the parameters obtained here lead to jet Lorentz factors at the deceleration radius between 70 and 300, anticorrelated with the jet initial aperture, and jet masses around 10-6 M? . Our results on the jet energy, opening Lorentz factor, and evacuation of material until breakout provide constraints on theoretical models of GRB jets.
Experimental Aerodynamic Heating to Simulated Shuttle Tiles

The heat transfer to simulated Shuttle thermal protection system tiles was investigated experimentally using a highly instrumented metallic thin wall tile arranged with other metal tiles in a staggered tile array. Cold-wall heating rate data for laminar and turbulent flow were obtained in the Langley 8-Foot High-Temperature Tunnel at a nominal Mach number of 7, a nominal total temperature of 3300 deg R, free-stream unit Reynolds number from 340,000 to 2,200,000 per foot, and free-stream dynamic pressure of 1.8 to 9.1 psia. Experimental data are presented to illustrate the effects of flow angularity and gap width on both local peak heating and overall heating loads.
I Hear, I Forget. I Do, I Understand: A Modified Moore-Method Mathematical Statistics Course

Moore introduced a method for graduate mathematics instruction that consisted primarily of individual student work on challenging proofs. Cohen described an adaptation with less explicit competition suitable for undergraduate students at a liberal arts college. This article details an adaptation of this modified Moore method to teach mathematical statistics, and describes ways that such an approach helps engage students and foster the teaching of statistics. Groups of students worked a set of three difficult problems (some theoretical, some applied) every two weeks. Class time was devoted to coaching sessions with the instructor, group meeting time, and class presentations. R was used to estimate solutions empirically, where analytic results were intractable, as well as to provide an environment to undertake simulation studies with the aim of deepening understanding and complementing analytic solutions. Each group presented comprehensive solutions to complement oral presentations. Development of parallel ...
The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2013☆

Abstract This is a review of papers published in the year 2013 that focus on the synthesis, reactivity, or properties of compounds containing a carbon-transition metal double or triple bond.
Hypothermia and cytokines in septic shock

Background: Hypothermic patients with sepsis have been reported to have a higher mortality than febrile septic patients. The failure to mount a febrile response in sepsis is poorly understood. Since the proinflammatory cytokines play a crucial role in the genesis of fever, we postulated that hypothermic patients with sepsis would have lower circulating levels of these cytokines than febrile patients¶Methods: Patients with septic shock who were enrolled into the placebo limb of the North American study of the safety and efficacy of murine monoclonal antibody to tumor necrosis factor for the treatment of septic shock (NORASEPT II) were analyzed. Body temperature, interleukin-6, tumor necrosis factor α, soluble tumor necrosis factor receptor-55, and soluble tumor necrosis factor receptor-75 concentrations were measured at enrollment. The study population was divided into a hypothermic (temperature ≤ 35.6 °C) and a febrile group (temperature ≥ 38.3 °C) according to the core temperature at enrollment (normothermia was an exclusion criteria). Clinical, demographic, and cytokine data were extracted, allowing for comparisons between these two groups of patients. In addition, the correlation between the core body temperature and cytokine levels at enrollment was determined¶Results: A complete data set was available for 930 patients; 195 patients (21 %) were hypothermic at enrollment. The 28-day survival of these patients was significantly lower than that of the febrile patients (34 % vs. 59 %, p < 0.001). Hypothermia (and enrollment temperature) were independent predictors of mortality. The hypothermic patients had a higher incidence of organ dysfunction at enrollment than the febrile patients. There was no significant difference in the cytokine profile between the two groups of patients. In addition, there was no correlation between the core body temperature at enrollment and the circulating levels of cytokines measured¶Conclusion: Hypothermic patients with septic shock have a significantly higher mortality with a higher incidence of organ dysfunction than febrile septic shock patients. The hypothermia in these patients cannot be explained by lower levels of circulating proinflammatory cytokines.
Solid-phase oligosaccharide synthesis and combinatorial carbohydrate libraries.

Preface. Contributors. Solid--Phase Carbohydrate Synthesis: The Early Work (W.--C. Haase & P. Seeberger). The Glycal Assembly Method on Solid Supports: Synthesis of Oligosaccharides and Glycoconjugates (P. Cirillo & S. Danishefsky). The Sulfoxide Glycosylation Method and its Application to Solid--Phase Oligosaccharide Synthesis and the Generation of Combinatorial Libraries (C. Taylor). The Use of O--Glycosyl Trichloroacetimidates for the Polymer--Supported Synthesis of Oligosaccharides (L. Knerr & R. Schmidt). Synthesis of Oligosaccharides on Solid Support Using Thioglycosides and Pentenyl Glycosides (V. Wittmann). Solid--Phase Oligosaccharide Synthesis Using Glycosyl Phosphates (W.--C. Haase, et al.). Stereoselective beta--Mannosylation on Polymer Support (Y. Ito & H. Ando). Tools for "On--Bead" Monitoring and Analysis in Solid--Phase Oligosaccharide Synthesis (W.--C. Haase, et al.). Polyethyleneglycol omega--Monomethylether (MPEG)--Supported Solution--Phase Synthesis of Oligosaccharides (J. Krepinsky & S. Douglas). Two--Direction Glycosylations for the Preparation of Libraries of Oligosaccharides (G.--J. Boons & T. Zhu). Carbohydrate Libraries in Solution Using Thioglycosides: From Multistep Synthesis to Programmable, One--Pot Synthesis (E. Simanek & C.--H. Wong). Carbohydrate Libraries by the Random Glycosylation Approach (O. Kanie & O. Hindsgaul). Solid--Phase Synthesis of Biologically Important Glycopeptides (N. Bezay & H. Kunz). Preparation and Screening of Glycopeptide Libraries (P. St. Hilaire, et al.). Index.
Cross-country variation in educational attainment: structural change or within-industry skill upgrading?

Educational attainment varies greatly across countries and within countries over time. This paper asks whether the variation in education is primarily due to industry composition or to within-industry skill intensities. The main finding is that within-industry variation accounts for at least two-thirds of the cross-country and the time-series variation in educational attainment. The within-industry education gaps are broadly consistent with a model of industry neutral cross-country differences in skilled labor productivity. These results suggest that theories of educational development should focus on skill upgrading within industries rather than structural change.
The Langevin method and Hubbard-like models

Abstract We reexamine the difficulties associated with application of the Langevin method to numerical simulation of models with non-positive definite statistical weights, including the Hubbard model. We show how to avoid the violent crossing of the zeroes of the weights and how to move those nodes away from the real axis. However, it still appears necessary to keep track of the sign (or phase) of the weight.
Fractals and cosmological large-scale structure.

Observations of galaxy-galaxy and cluster-cluster correlations as well as other large-scale structure can be fit with a 'limited' fractal with dimension D of about 1.2. This is not a 'pure' fractal out to the horizon: the distribution shifts from power law to random behavior at some large scale. If the observed patterns and structures are formed through an aggregation growth process, the fractal dimension D can serve as an interesting constraint on the properties of the stochastic motion responsible for limiting the fractal structure. In particular, it is found that the observed fractal should have grown from two-dimensional sheetlike objects such as pancakes, domain walls, or string wakes. This result is generic and does not depend on the details of the growth process.
Modular Pluggable Analyses for Data Structure Consistency

Hob is a program analysis system that enables the focused application of multiple analyses to different modules in the same program. In our approach, each module encapsulates one or more data structures and uses membership in abstract sets to characterize how objects participate in data structures. Each analysis verifies that the implementation of the module 1) preserves important internal data structure consistency properties and 2) correctly implements a set algebra interface that characterizes the effects of operations on the data structure. Collectively, the analyses use the set algebra to 1) characterize how objects participate in multiple data structures and to 2) enable the interanalysis communication required to verify properties that depend on multiple modules analyzed by different analyses. We implemented our system and deployed several pluggable analyses, including a flag analysis plug-in for modules in which abstract set membership is determined by a flag field in each object, a PALE shape analysis plug-in, and a theorem proving plug-in for analyzing arbitrarily complicated data structures. Our experience shows that our system can effectively 1) verify the consistency of data structures encapsulated within a single module and 2) combine analysis results from different analysis plug-ins to verify properties involving objects shared by multiple modules analyzed by different analyses
A PURE PERMANENT MAGNET - TWO PLANE FOCUSING - TAPERED WIGGLER FOR A HIGH AVERAGE POWER FEL

A high-average power FEL is under construction at Los Alamos. The FEL will have aspects of both an oscillator and a SASE (self-amplified spontaneous emission) device. That is, a high-gain and high- extraction efficiency wiggler will be used with a very low-Q optical resonator. FEL simulations reveal that a tapered wiggler with two- plane focusing is required to obtain desired performance. The wiggler is comprised of a I meter long untapered section followed by a 1 meter tapered section. The taper is achieved with the magnetic gap and not the wiggler period which is constant at 2 cm. The gap is tapered from 5.9 mm to 8.8 mm. The, gap, rather than the period, is tapered to avoid vignetting of the 16 {mu}m optical beam. Two-plane focusing is necessary to maintain high current density and thus high gain through out the 2 meter long wiggler. Several magnetic designs have been considered for the wiggler. The leading candidate approach is a pure permanent wiggler with pole faces that are cut to roughly approximate the classical parabolic pole face design. Focusing is provided by the sextupole component of the wiggler magnetic field and is often called ``natural`` or ``betatron`` focusing. Details ofmore » the design will be presented.« less
Intramolecular Electron Transfer in Fullerene/Ferrocene Based Donor−Bridge−Acceptor Dyads

A systematic steady-state fluorescence and time-resolved flash photolytic investigation of a series of covalently linked fullerene/ferrocene based donor−bridge−acceptor dyads is reported as a function of the nature of the spacer between the donor site (ferrocene) and acceptor site (fullerene) and the dielectric constant of the medium. The fluorescence of the investigated dyads 2 (Φrel = 0.17 × 10-4), 3 (Φrel = 0.78 × 10-4), 4 (Φrel = 1.5 × 10-4), 5 (Φrel = 0.7 × 10-4), and 6 (Φrel = 2.9 × 10-4) in methylcyclohexane at 77 K were substantially quenched, relative to N-methylfulleropyrrolidine 1 (Φrel = 6.0 × 10-4), indicating intramolecular quenching of the fullerene excited singlet state. Excitation of N-methylfulleropyrrolidine revealed the immediate formation of the excited singlet state, with λmax around 886 nm. A rapid intersystem crossing (τ1/2 = 1.2 ps) to the excited triplet state was observed with characteristic absorption around 705 nm. Picosecond resolved photolysis of dyads 2−6 in toluene showed ...
A Modeling Study of the Effects of Ice-Phase Microphysical Processes on Trace Chemical Removal Efficiencies

A simple cloud-chemistry model has been developed to study the effects of specific microphysical processes of precipitation formation and scavenging on the efficiency with which clouds remove trace chemicals form the atmosphere. The model is designed to let an isolated precipitation particle fall through the mixed-phase zone of a steady-state background cloud derived from the ascent of a Lagrangian parcel in which given mixing ratios of SO2, CO2 and NH3 are in equilibrium with the aqueous phase. The precipitation particle is allowed to acquire water mass by both vapor deposition and accretion of supercooled cloud water and solute content by gaseous entrapment in rime ice, as parameterized from prior laboratory experiments. The concept of a relative removal efficiency has been employed to identify the important microphysical fractionation processes within the cloud. The model calculations show that the removal efficiencies of the chemical constituents in the cloud nuclei and soluble trace gases are controlled largely by the accretional growth process. Even with modest solubilities, a trace gas such as SO2 is estimated to be removed much more efficiently than is water vapor via cold-cloud precipitation because of substantial entrapment of the gas during rime-ice formation.