cssi/SciSciGPT-SciSciNet huggingface dataset:
AN EFFICIENT METHOD FOR THE REDUCTIVE TRANSPOSITION OF ALLYLIC ALCOHOLS

Abstract The Mitsunobu reaction of allylic alcohols with o -nitrobenzenesulfonylhydrazine (NBSH) as nucleophile proceeds at −30 °C with invertive displacement; warming the resultant N -allylic sulfonylhydrazine derivative to 23 °C then leads to allylic diazene formation followed by sigmatropic elimination of dinitrogen. This one-step method for reductive 1,3-transposition is shown to be efficient and highly regio- and stereocontrolled within a wide range of allylic alcohol substrates.
Proposed XML‐based three‐dimensional atom probe data standard

A platform-independent extensible markup language (XML) standard to describe all types of three-dimensional and classical atom probe data is proposed. An associated XML-based peak assignment or range file format is also described. XML-based databases of elemental parameters and predefined colors are described. These standard formats should facilitate the exchange and analysis of three-dimensional atom probe data. Copyright © 2004 John Wiley & Sons, Ltd.
Highly selective synthesis of tetra-substituted furans and cyclopropenes: copper(I)-catalyzed formal cycloadditions of internal aryl alkynes and diazoacetates

A convenient Cu(I)-catalyzed cycloaddition of electron rich internal aryl alkynes and diazoacetates was discovered for the chemoselective and regioselective synthesis of tetra-substituted furans and cyclopropenes in moderate isolated yields (18–67%), and alkyne conversion (29–73%).
Development of Automated Fixture Planning Systems

Fixturing is an important manufacturing activity. The computer[ aided fixture design technique is being rapidly developed to reduce the lead time involved in manufacturing planning. An automated fixture configuration design system has been developed to select automatically modular fixture components and place them in position with satisfactory assembly relationships. In this paper, an automated fixturing planning system is is presented in which fixturing surfaces and points are automatically determined based on workpiece geometry and operational information. Fixturing surface accessibility, feature accuracy, and fixturing stability are the main concerns in the fixture planning. The system development, the fixture planning decision procedure, and an implementation example are presented in the paper.
Development of a general Pd(II)-catalyzed intermolecular hydroalkoxylation reaction of vinylphenols by using a sacrificial alcohol as the hydride source.

A general hydroalkoxylation of vinylphenols has been successfully developed wherein primary, secondary, and tertiary alcohols can be used as nucleophiles. The key conceptual breakthrough is the use of sec-phenethyl alcohol at relatively low concentrations as the sacrificial alcohol to undergo oxidation and provide the proposed Pd−H intermediate.
Quantum Extremal Surfaces: Holographic Entanglement Entropy beyond the Classical Regime

We propose that holographic entanglement entropy can be calculated at arbitrary orders in the bulk Planck constant using the concept of a “quantum extremal surface”: a surface which extremizes the generalized entropy, i.e. the sum of area and bulk entanglement entropy. At leading order in bulk quantum corrections, our proposal agrees with the formula of Faulkner, Lewkowycz, and Maldacena, which was derived only at this order; beyond leading order corrections, the two conjectures diverge. Quantum extremal surfaces lie outside the causal domain of influence of the boundary region as well as its complement, and in some spacetimes there are barriers preventing them from entering certain regions. We comment on the implications for bulk reconstruction.
Margin requirements and equilibrium asset prices

Abstract This paper studies the effect of margin requirements on asset prices and trading volume in a general equilibrium asset pricing model where Epstein–Zin investors differ in their degree of risk aversion. Under the assumptions of unit intertemporal elasticity of substitution and zero net supply of riskless assets, I show analytically that binding margin requirements do not affect stock prices. This result stands in contrast to previous partial equilibrium analysis where fixed margin requirements increase the volatility of stock prices. In this framework, binding margin requirements induce a fall in the riskless rate, increase its volatility, and increase stock trading volume.
Signaling thresholds govern heterogeneity in IL-7-receptor-mediated responses of naïve CD8 + T cells

Variable sensitivity to T-cell-receptor (TCR)- and IL-7-receptor (IL-7R)-mediated homeostatic signals among naive T cells has thus far been largely attributed to differences in TCR specificity. We show here that even when withdrawn from self-peptide-induced TCR stimulation, CD8+ T cells exhibit heterogeneous responses to interleukin-7 (IL-7) that are mechanistically associated with IL-7R expression differences that correlate with relative CD5 expression. Whereas CD5hi and CD5lo T cells survive equivalently in the presence of saturating IL-7 levels in vitro, CD5hi T cells proliferate more robustly. Conversely, CD5lo T cells exhibit prolonged survival when withdrawn from homeostatic stimuli. Through quantitative experimental analysis of signaling downstream of IL-7R, we find that the enhanced IL-7 responsiveness of CD5hi T cells is directly related to their greater surface IL-7R expression. Further, we identify a quantitative threshold in IL-7R-mediated signaling capacity required for proliferation that lies well above an analogous threshold requirement for survival. These distinct thresholds allow subtle differences in IL-7R expression between CD5lo and CD5hi T cells to give rise to significant variations in their respective IL-7-induced proliferation, without altering survival. Heterogeneous IL-7 responsiveness is observed similarly in vivo, with CD5hi naive T cells proliferating preferentially in lymphopenic mice or lymphoreplete mice administered with exogenous IL-7. However, IL-7 in lymphoreplete mice appears to be maintained at an effective level for preserving homeostasis, such that neither CD5hi IL-7Rhi nor CD5lo IL-7Rlo T cells proliferate or survive preferentially. Our findings indicate that IL-7R-mediated signaling not only maintains the size but also impacts the diversity of the naive T-cell repertoire.
Semiparametric estimation of censored selection models with a nonparametric selection mechanism

Abstract In this paper, estimation of the coefficients in a ‘single-index selectivity bias’ model is considered under the assumption that the selection correction function depends on the conditional mean of some observable ‘selection’ variable. The estimation method follows a familiar ‘two-step’ strategy: the first step uses a nonparametric regression estimator for the selection variable, while the second step uses a weighted instrumental variables estimator for the coefficients in the equation of interest. The paper gives conditions under which the proposed estimator is root- n -consistent and asymptotically normal. The proposed method is applied to data on labor supply.
Assorted weak matrix elements involving the bottom quark

Abstract As part of a larger project to estimate the f B decay constant, we are calculating f B static using a variational smearing method in an effort to improve accuracy. Preliminary results for the static B B parameter and HQET two point functions are also presented.
The Effect Of Injection Timing, Enhanced Aftercooling, And Low Sulfur-low Aromatic Diesel Fuel On Locomotive Exhaust Emissions

An experimental study was performed to demonstrate the fuel economy and exhaust emissions implications of retarding fuel injection timing, enhancing charge air aftercooling, and using low-sulfur, low-aromatic diesel fuel for locomotive engines. Steady-state gaseous and particulate emission data are presented from two 12-cylinder diesel locomotive engines. The two laboratory engines, an EMD 645E3B and a GE 7FDL, are each rated at 1860 kW (2500 hp) and represent the majority of the locomotive fleet in North America. Each engine was tested for total hydrocarbons (HC), carbon monoxide (CO), oxides of nitrogen (NO[sub x]), and particulate. Emissions were measured at three steady-state operating conditions: rated speed and load, idle, and an intermediate speed and load. Test results on the EMD engine indicate that a 4 deg injection timing retard, along with a low-sulfur, low-aromatic fuel and enhanced aftercooling, was effective in reducing NO[sub x] from 10.5 g/hp-h to 7.2 g/hp-h; however, particulates increased from 0.15 g/hp-h to 0.19 g/hp-h, and fuel efficiency was 4.3 percent worse. Similar observations were made with the GE engine. This paper gives details on the test engines, the measurement procedures, and the emission results.
Convenient method for the preparation of some polyhydroxamic acids : Michael addition of amines to acrylohydroxamic acid derivatives

Abstract Reagents 1, 2, and 3 are readily prepared by the reaction of the appropriate hydroxylamine derivatives with acryloyl chloride. They undergo Michael addition with a variety of amines to give the corresponding O-protected hydroxamate derivatives in moderate to good yields. Subsequent removal of the protecting group provides a convenient method for the preparation of a number of mono, di, tri and tetrahydroxamic acids.
Up-Regulation of Hepatitis C Virus Replication and Production by Inhibition of MEK/ERK Signaling

Background Viruses interact with and exploit the host cellular machinery for their multiplication and propagation. The MEK/ERK signaling pathway positively regulates replication of many RNA viruses. However, whether and how this signaling pathway affects hepatitis C virus (HCV) replication and production is not well understood. Methods and results In this study, we took advantage of two well-characterized MEK/ERK inhibitors and MEK/ERK dominant negative mutants and investigated the roles of the MEK/ERK signaling pathway in HCV gene expression and replication. We showed that inhibition of MEK/ERK signaling enhanced HCV gene expression, plus- and minus-strand RNA synthesis, and virus production. In addition, we showed that this enhancement was independent of interferon-alpha (IFN-alpha) antiviral activity and did not require prior activation of the MEK/ERK signaling pathway. Furthermore, we showed that only MEK and ERK-2 but not ERK-1 was involved in HCV replication, likely through regulation of HCV RNA translation. Conclusions Taken together, these results demonstrate a negative regulatory role of the MEK/ERK signaling pathway in HCV replication and suggest a potential risk in targeting this signaling pathway to treat and prevent neoplastic transformation of HCV-infected liver cells.
Power-law behavior of bond energy correlators in a Kitaev-type model with a stable parton Fermi surface

We study bond energy correlation functions in an exactly solvable quantum spin model of Kitaev type on the kagome lattice with stable Fermi surface of partons proposed recently by Chua et al. [arXiv:1010.1035v1]. Even though any spin correlations are of ultrashort range, we find that the bond energy correlations have power-law behavior with a $1/|\mathbit{r}|{}^{3}$ envelope and oscillations at incommensurate wave vectors. We determine the corresponding singular surfaces in momentum space, which provide a gauge-invariant characterization of this gapless spin liquid.
Common and Variant Gene Fusions Predict Distinct Clinical Phenotypes in Rhabdomyosarcoma

PURPOSEWe evaluated the clinical features of the common PAX3-FKHR and variant PAX7-FKHR gene fusions observed in rhabdomyosarcoma.PATIENTS AND METHODSReverse-transcriptase polymerase chain reaction (RT-PCR) assays were used to detect the gene fusions in 34 cases of rhabdomyosarcoma. Clinical data were obtained retrospectively and compared with the molecular results.RESULTSThe PAX3-FKHR and PAX7-FKHR gene fusions were present in tumors from 18 and 16 patients, respectively. The group with a PAX7-FKHR fusion was younger (P = .01) and presented more often with an extremity lesion (82% v 22%; P = .001). PAX7-FKHR tumors were more often localized than PAX3-FKHR tumors (P = .03). In patients with metastatic disease at diagnosis, the patterns were different: PAX7-FKHR patients had metastatic disease that involved only bone (n = 2) and distant nodes (n = 2), while the PAX3-FKHR group had multiple sites involved, including bone (n = 7), marrow (n = 7), lungs (n = 3), distant nodes (n = 2), skin (n = 1), and brain ...
A Highly Enantioselective Route to Either Enantiomer of Both α- and β-Amino Acid Derivatives

This report describes the unprecedented use of unmodified aldehydes as donors in a catalytic asymmetric Mannich-type reaction. The proline-catalyzed reaction of N-PMP-protected α-imino ethyl glyoxylate with unmodified aliphatic aldehydes provided a general and very mild entry to either enantiomer of β-amino and α-amino acids and derivatives in high yield and stereoselectivity. Six of the seven aldehydes studied yielded products with ee values of 99% or greater. The diastereoselectivity of the reaction increased with the bulkiness of the substituents of the aldehyde donor in the order R = Me < Et < i-Pr < n-Pent. In five of the cases studied, excellent syn stereoselectivities were achieved. In addition, the corresponding chiral β-amino aldehyde adducts can be readily converted to the corresponding amino acid derivatives. Most significantly, this approach provides facile access to substituted β-lactams.
Intersection bodies and generalized cosine transforms

The paper is focused on intimate connection between geometric properties of intersection bodies in convex geometry and generalized cosine transforms in harmonic analysis. A new concept of ?-intersection body, that unifies some known classes of geometric objects, is introduced. A parallel between trace theorems in function theory, restriction onto lower-dimensional subspaces of the spherical Radon transforms and the generalized cosine transforms, and sections of ?-intersection bodies is established. New integral formulas for different classes of cosine transforms are obtained and examples of ?-intersection bodies are given. We also revisit some known facts in this area and give them new simple proofs
Synthesis of Fluorinated Dienylic Stannanes Via the Wadsworth-Emmons Reaction

Abstract Geminal difluorination of dithiolane 9 affords bis benzyl ether 4b which is converted to beta-fluoroenals 3Z/3E. Reaction of these enals with the stannylmethyl Wadsworth-Emmons reagent 2 produces dienyl esters 14Z/14E which are converted to highly functionalized dienylic stannanes 1Z and 1E.
Evaporation of dusty molecular clouds in AGN

Abstract We investigate dusty molecular clouds on the inner edge of the torus which are exposed to the strong ionizing continuum of the active nucleus. The incident ionizing flux pressurizes the cloud and evaporates its outer layers in a wind. The dust grains are sputtered in this hot ( T ≥ 10 6 K) wind. We show that the cloud evaporation time is comparable to the radial drift time of clouds in the torus, but longer than the orbital time. The clouds produce line emission typical of highly ionized gas. Dust opacity prevents the torus line emission from overpowering the broad and narrow line regions, however the torus may be the source of the coronal lines seen in some AGN.
A Lyman Break Galaxy Candidate at z ~ 9*

We report the discovery of a z ~ 9 Lyman break galaxy candidate, selected from the NICMOS Parallel Imaging Survey as a J-dropout with J110 − H160 = 1.7. Spitzer/IRAC photometry reveals that the galaxy has a blue H160 − 3.6 μm color and a spectral break between 3.6 and 4.5 μm. We interpret this break as the Balmer break and derive a best-fit photometric redshift of z ~ 9. We use Monte Carlo simulations to test the significance of this photometric redshift, and we show that there is a 96% probability of z ≥ 7. We estimate that the lower limit to the comoving number density of such galaxies at z ~ 9 is phi > 3.8 × 10^−6 Mpc^−3. If the high redshift of this galaxy is confirmed, this will indicate that the luminous end of the rest-frame UV luminosity function has not evolved substantially from z ~ 9 to z ~ 3. Still, some small degeneracy remains between this z ~ 9 model and models at z ~ 2–3; deep optical imaging (reaching IAB ~ 29) can rule out the lower z models.
The Origins of Lattice Gauge Theory

The main focus of this talk is an anecdotal account of the history underlying my 1974 article entitled 'Confinement of Quarks.' In preparing this talk, I will draw on a historical interview conducted by the project for History of Recent Science and Technology at the Dibner Institute for the History of Science and Technology at MIT, and on a theory of invention proposed by Peter Drucker in his book 'Innovation and Entrepreneurship.' I will explain this theory; no background is needed. The account will start with related work in the 1960's. I will end the talk with a plea for lattice gauge researchers to be alert for unexpected scalar or vector colored particles that are invisible to experimentalists yet could start to spoil the agreement of computations with experiment. Note: In association with the Symposium ' 'Lattice 2004,' June 21 to June 26, 2004.
Photodisintegration of Three-Particle Nuclei

We show that the ${\mathrm{He}}^{3}$ and ${\mathrm{H}}^{3}$ photodisintegration reactions are to a large extent independent of the detailed properties of the three-nucleon ground state, but depend crucially on the nuclear interaction in the final continuum states. The bound-state properties considered are the analytic form of the principal $S$ state, the asymptotic behavior, the ${S}^{\ensuremath{'}}$ state, and the two-nucleon short-range repulsion. Since the rms radius of the bound state determines the over-all magnitude of the cross section, predictions of different wave functions with the same radius are compared. The final states are described by the Faddeev equations in the separable approximation. If the final-state interactions are correctly included, then the low-energy cross sections for the ${\mathrm{He}}^{3}(\ensuremath{\gamma}, p)d$ reaction are enhanced by 20-25%, and the cross sections for ${\mathrm{He}}^{3}(\ensuremath{\gamma}, n)2p$ are reduced by approximately 100%. A simultaneous but rough agreement is possible for the total two- and three-body breakup cross sections and the charge form factors of the three-particle nuclei; but, within the theoretical framework adopted, the two-body differential cross sections at 90\ifmmode^\circ\else\textdegree\fi{} and the charge-form-factor data cannot be reconciled.
6D supergravity without tensor multiplets

We systematically investigate the finite set of possible gauge groups and matter content for \( {\mathcal{N} = 1} \) supergravity theories in six dimensions with no tensor multiplets, focusing on nonabelian gauge groups which are a product of SU(N) factors. We identify a number of models which obey all known low-energy consistency conditions, but which have no known string theory realization. Many of these models contain novel matter representations, suggesting possible new string theory constructions. Many of the most exotic matter structures arise in models which precisely saturate the gravitational anomaly bound on the number of hypermultiplets. Such models have a rigid symmetry structure, in the sense that there are no moduli which leave the full gauge group unbroken.
RADIATIVE TORQUES ALIGNMENT IN THE PRESENCE OF PINWHEEL TORQUES

We study the alignment of grains subject to both radiative torques and pinwheel torques while accounting for thermal flipping of grains. By pinwheel torques we refer to all systematic torques that are fixed in grain body axes, including the radiative torques arising from scattering and absorption of isotropic radiation. We discuss new types of pinwheel torques, which are systematic torques arising from infrared emission and torques arising from the interaction of grains with ions and electrons in hot plasma. We show that both types of torques are long-lived, i.e., may exist longer than gaseous damping time. We compare these torques with the torques introduced by E. Purcell, namely, torques due to H2 formation, the variation of accommodation coefficient for gaseous collisions and photoelectric emission. Furthermore, we revise the Lazarian and Draine model for grain thermal flipping. We calculate mean flipping timescale induced by Barnett and nuclear relaxation for both paramagnetic and superparamagnetic grains, in the presence of stochastic torques associated with pinwheel torques, e.g., the stochastic torques arising from H2 formation, and gas bombardment. We show that the combined effect of internal relaxation and stochastic torques can result in fast flipping for sufficiently small grains and, because of this, they get thermally trapped, i.e., rotate thermally in spite of the presence of pinwheel torques. For sufficiently large grains, we show that the pinwheel torques can increase the degree of grain alignment achievable with the radiative torques by increasing the magnitude of the angular momentum of low attractor points and/or by driving grains to new high attractor points.
Non-isogenous superelliptic Jacobians

Let l be an odd prime. Let K be a field of characteristic zero with algebraic closure K a . Let n, m ≥ 4 be integers that are not divisible by l. Let f(x), h(x) ∈ K[x] be irreducible separable polynomials of degree n and m respectively. Suppose that the Galois group Gal(f) of f acts doubly transitively on the set of roots of f and that Gal(h) acts doubly transitively on as well. Let J(C f ,l) and J(C h ,l) be the Jacobians of the superelliptic curves C f ,l:y l =f(x) and C h ,l:y l =h(x) respectively. We prove that J(C f ,l) and J(C h ,l) are not isogenous over K a if the splitting fields of f and h are linearly disjoint over K and K contains a primitive lth root of unity.
Aviram?Ratner rectifying mechanism for DNA base-pair sequencing through graphene nanogaps

We demonstrate that biological molecules such as Watson–Crick DNA base pairs can behave as biological Aviram–Ratner electrical rectifiers because of the spatial separation and weak hydrogen bonding between the nucleobases. We have performed a parallel computational implementation of the ab initio non-equilibrium Green’s function (NEGF) theory to determine the electrical response of graphene—base-pair—graphene junctions. The results show an asymmetric (rectifying) current–voltage response for the cytosine–guanine base pair adsorbed on a graphene nanogap. In sharp contrast we find a symmetric response for the thymine–adenine case. We propose applying the asymmetry of the current–voltage response as a sensing criterion to the technological challenge of rapid DNA sequencing via graphene nanogaps.
An Analog Checker with Input-Relative Tolerance for Duplicate Signals

We discuss the design of a novel analog checker that monitors two duplicate signals and provides a digital error indication when their absolute difference is unacceptably large. The key feature of the proposed checker is that it establishes a test criterion that is dynamically adapted to the magnitude of its input signals, thus enhancing the accuracy of assessing their relative discrepancy. Consequently, when this checker is utilized in concurrent error detection, it diminishes the probability of both false negatives and false positives. Likewise, when employed for off-line test purposes, the checker supports both high yield and high fault coverage. In contrast, checkers implementing a static test criterion may only be tuned to achieve efficiently one of the aforementioned objectives.
Ultimate limit of field confinement by surface plasmon polaritons.

We show that electric field confinement in surface plasmon polaritons propagating at metal/dielectric interfaces enhances the loss due to Landau damping, which effectively limits the degree of confinement itself. We prove that Landau damping, and associated with it surface collision damping, follow directly from the Lindhard formula for the dielectric constant of a free electron gas. Furthermore, we demonstrate that even if all of the conventional loss mechanisms, caused by phonons, electron–electron interactions, and interface roughness scattering, were eliminated, the maximum attainable degree of confinement and the loss accompanying it would not change significantly compared to the best existing plasmonic materials, such as silver.
Heat Transfer Enhancement Using Shaped Polymer Tubes: Fin Analysis

The use of polymer tubes for heat exchanger tube bundles is of interest in many applications where corrosion, mineral build-up and/or weight are important. The challenge of overcoming the low thermal conductivity of polymers may be met by using many small-diameter, thin-walled polymer tubes and this route is being pursued by industry. We propose the use of unique shaped tubes that are easily extruded using polymeric materials. The shaped tube are streamlined to reduce form drag yet the inside flow passage is kept circular to maintain the pressure capability of the tube. Special treatment is required to predict convective heat transfer rates because the temperature distribution along the outer surface of the shaped tubes is nonuniform. The average forced convection Nusselt number correlations developed for these noncircular tubes can not be used directly to determine heat transfer rate. Heat transfer rates of shaped tubes are characterised by treating the tubes as a base circular tube to which longitudinal fin(s) are added. Numerical solution of an energy balance on the fin provides the surface temperature distribution and a shaped tube efficiency, which can be used in the same manner as a fin efficiency to determine the outside connective resistance
The Ecology of Arsenic

Arsenic is a metalloid whose name conjures up images of murder. Nonetheless, certain prokaryotes use arsenic oxyanions for energy generation, either by oxidizing arsenite or by respiring arsenate. These microbes are phylogenetically diverse and occur in a wide range of habitats. Arsenic cycling may take place in the absence of oxygen and can contribute to organic matter oxidation. In aquifers, these microbial reactions may mobilize arsenic from the solid to the aqueous phase, resulting in contaminated drinking water. Here we review what is known about arsenic-metabolizing bacteria and their potential impact on speciation and mobilization of arsenic in nature.
The SERENDIP piggyback SETI project

The SERENDIP project is an ongoing program of monitoring and processing broadband radio signals acquired by existing radio astronomy observatories. SERENDIP operates in a piggyback mode: it makes use of whatever observing plan (sequence of frequencies, sky coordinates, and polarizations) is under way at its host observatory. Moreover, the SERENDIP data acquisition system, once installed, operates autonomously. This approach makes it possible to obtain large amounts of high quality observing time in a manner that is economical and that does not adversely affect ongoing radio astronomy survey work. The SERENDIP II system has been installed at the NRAO 300-foot telescope at Green Bank, West Virginia, and has operated there for several thousand hours. In this report, we summarize our findings from these observations and describe the present status of the project. Two key elements of SERENDIP are the automated data acquisition system that uses adaptive thresholds and logs only statistically significant peaks in the real-time power spectra, and the subsequent off-line analysis programs that identify and reject a variety of interference signals. Several specific correlations have been identified that offer promise. At present, the development and testing of these interference rejection algorithms is the main thrust of our work.
The use of metamodeling techniques for optimization under uncertainty

Metamodeling techniques have been widely used in engineering design to improve efficiency in the simulation and optimization of design systems that involve computationally expensive simulation programs. Many existing applications are restricted to deterministic optimization. Very few studies have been conducted on studying the accuracy of using metamodels for optimization under uncertainty. In this paper, using a two-bar structure system design as an example, various metamodeling techniques are tested for different formulations of optimization under uncertainty. Observations are made on the applicability and accuracy of these techniques, the impact of sample size, and the optimization performance when different formulations are used to incorporate uncertainty. Some important issues for applying metamodels to optimization under uncertainty are discussed.
Enantioselective Organocatalytic Michael Addition of Aldehydes to Nitroethylene: Efficient Access to γ2-Amino Acids

Enantioselective organocatalytic Michael addition of aldehydes to nitroethylene catalyzed by (S)-diphenylprolinol silyl ether provides β-substituted-δ-nitroalcohols in nearly optically pure form (96−99% ee). The Michael adducts bear a single substituent adjacent to the carbonyl and can be efficiently converted to protected γ2-amino acids, which are essential for the systematic conformational studies of γ-peptide foldamers.
AN APPARATUS FOR THE EFFICIENT REMOVAL OF H2O FROM REACTION MIXTURES

Abstract An apparatus has been designed that facilitates the azeotropic removal of H2O from a reaction mixture. Representative condensation reactions in which this apparatus was used include acetal, imine, and enamine formation.
Equivalence of the generalized Lie-Hori method and the method of averaging

In this investigation, a comparison is made of two methods for developing perturbation theories for non-canonical dynamical systems. The methods compared are the generalized Lie-Hori method and the method of averaging. In the comparison presented here, the equivalence of the methods up to the second order in the small parameter is shown. However, the approach used can be extended to demonstrate the equivalence for higher orders. To illustrate the equivalence Duffing's equation, the van der Pol equation and the oscillator with quadratic damping problem are solved using each method.
Hypergeometric series, modular linear differential equations and vector-valued modular forms

We survey the theory of vector-valued modular forms and their connections with modular differential equations and Fuchsian equations over the three-punctured sphere. We present a number of numerical examples showing how the theory in dimensions 2 and 3 leads naturally to close connections between modular forms and hypergeometric series.
Corporate governance proposals and shareholder activism: the role of institutional investors

Abstract We study shareholder proposals across a period of substantial activity and find systematic differences both across sponsor identity and across time. To measure the success of shareholder activism, we examine voting outcomes and short-term market reactions conditioned on proposal type and sponsor identity. The voting analysis documents that sponsor identity, issue type, prior performance and time period are important influences on the voting outcome. Proposals sponsored by institutions or coordinated groups appear to act as substitutes gaining substantially more support than proposals sponsored by individuals. The nature of the stock market reaction, while typically small, varies according to the issue and the sponsor identity.
A Generalization of Lie's Theorem

We prove that in a locally finite dimensional Lie algebra L, any maximal, locally solvable subalgebra is the stabilizer of a maximal, generalized flag in an integrable, faithful module over L.
Jet Noise Shielding Provided by a Hybrid Wing Body Aircraft.

One approach toward achieving NASA's aggressive N+2 noise goal of 42 EPNdB cumulative margin below Stage 4 is through the use of novel vehicle configurations like the hybrid wing body. Jet noise measurements from a hybrid wing body acoustic test in the NASA Langley 14- by 22-Foot Subsonic Tunnel are described. Two dual-stream, heated Compact Jet Engine Simulator units are mounted underneath the inverted hybrid wing body model on a traversable support to permit measurement of varying levels of shielding provided by the fuselage. Both an axisymmetric and low noise chevron nozzle set are investigated in the context of shielding. The unshielded chevron nozzle set shows 1–2 dB of source noise reduction (relative to the unshielded axisymmetric nozzle set) with some penalties at higher frequencies. Shielding of the axisymmetric nozzles shows up to 6.5 dB of reduction at high frequency. The combination of shielding and low noise chevrons shows benefits beyond the expected additive benefits of the two, up to 10 dB, due to the effective migration of the jet source peak noise location upstream for increased shielding effectiveness. Jet noise source maps from phased array results processed with the deconvolution approach for the mapping of acoustic sources algorithm reinforce these observations.
Fully Leakage-Resilient Signatures

A signature scheme is fully leakage resilient (Katz and Vaikuntanathan, ASIACRYPT'09) if it is existentially unforgeable under an adaptive chosen-message attack even in a setting where an adversary may obtain bounded (yet arbitrary) leakage information on all intermediate values that are used throughout the lifetime of the system. This is a strong and meaningful notion of security that captures a wide range of side-channel attacks. One of the main challenges in constructing fully leakage-resilient signature schemes is dealing with leakage that may depend on the random bits used by the signing algorithm, and constructions of such schemes are known only in the random-oracle model. Moreover, even in the random-oracle model, known schemes are only resilient to leakage of less than half the length of their signing key. In this paper we construct the first fully leakage-resilient signature schemes without random oracles. We present a scheme that is resilient to any leakage of length (1?o(1))L bits, where L is the length of the signing key. Our approach relies on generic cryptographic primitives, and at the same time admits rather efficient instantiations based on specific number-theoretic assumptions. In addition, we show that our approach extends to the continual-leakage model, recently introduced by Dodis, Haralambiev, Lopez-Alt and Wichs (FOCS'10), and by Brakerski, Tauman Kalai, Katz and Vaikuntanathan (FOCS'10). In this model the signing key is allowed to be refreshed, while its corresponding verification key remains fixed, and the amount of leakage is assumed to be bounded only in between any two successive key refreshes.
An efficient method for the preparation of alkylidenecyclopropanes

Abstract Yields obtained from Wittig reactions with cyclopropylidenetriphenylphosphorane are greatly improved by addition of the phase-transfer catalyst, TDA-1.
Self-validated variance-based methods for sensitivity analysis of model outputs

Global sensitivity analysis (GSA) has the advantage over local sensitivity analysis in that GSA does not require strong model assumptions such as linearity or monotonicity. As a result, GSA methods such as those based on variance decomposition are well-suited to multi-physics models, which are often plagued by large nonlinearities. However, as with many other sampling-based methods, inadequate sample size can badly pollute the result accuracies. A natural remedy is to adaptively increase the sample size until sufficient accuracy is obtained. This paper proposes an iterative methodology comprising mechanisms for guiding sample size selection and self-assessing result accuracy. The elegant features in the proposed methodology are the adaptive refinement strategies for stratified designs. We first apply this iterative methodology to the design of a self-validated first-order sensitivity analysis algorithm. We also extend this methodology to propose a self-validated second-order sensitivity analysis algorithm based on refining replicated orthogonal array designs. Several numerical experiments are given to demonstrate the effectiveness of these methods.
LHC Reach for Gauge Mediated Supersymmetry Breaking Models Via Prompt Photon Channels

Abstract We evaluate the supersymmetry reach of the Large Hadron Collider within the gauge-mediated low energy supersymmetry breaking framework, assuming that a neutralino is the second lightest sparticle and that it decays promptly into a gravitino which escapes detection. We find that the maximum reach is obtained via a search for inclusive γγ+ E / T events coming dominantly from chargino and neutralino production. Assuming an integrated luminosity of 10 fb−1, we find that LHC experiments will be able to probe values of the model parameter Λ≲400 TeV, corresponding to m g ≤2.8 TeV. A measure of the model parameter Λ may be possible from the photon pT spectrum.
Fruits of Serendipity in Research of Titanium Compounds: from “Sodium Tianide” to Titanium Nitride Whiskers

The usefulness of complementing the results of X-ray diffraction (XRD) with an independent technique such as Raman spectroscopy (RS) was demonstrated by the successful identification of the products (TiN and Na-titanates) from the reaction of TiO 2 with NaCN. The study of other reactions of NaCN with several Ti-compounds to produce TiN powder led to the development of new syntheses reactions for known [TiP 2 O 7 , NaTi 2 (PO 4 ) 3 and Na x TiO 2 ] and for new [(TiO) 2 P 2 O 7 , Na(TiO)PO 4 and Na 4 (TiO)(PO 4 ) 2 ] compounds. The reaction of Na x TiO 2 with NaCN produced TiN in the form of whiskers.
Realizing unconventional quantum magnetism with symmetric top molecules

We demonstrate that ultracold symmetric top molecules loaded into an optical lattice can realize highly tunable and unconventional models of quantum magnetism, such as an XYZ Heisenberg spin model. We show that anisotropic dipole?dipole interactions between molecules can lead to effective spin?spin interactions which exchange spin and orbital angular momentum. This exchange produces effective spin models which do not conserve magnetization and feature tunable degrees of spatial and spin?coupling anisotropy. In addition to deriving pure spin models when molecules are pinned in a deep optical lattice, we show that models of itinerant magnetism are possible when molecules can tunnel through the lattice. Additionally, we demonstrate rich tunability of effective model parameters using only a single microwave frequency, in contrast to proposals with diatomic molecules, which often require many microwave frequencies. Our results are germane not only for experiments with polyatomic symmetric top molecules, such as methyl fluoride (CH3F), but also diatomic molecules with an effective symmetric top structure, such as the hydroxyl radical OH.
Silica Molecular Dynamic Force Fields- A Practical Assessment

The purpose of this paper is to compare simple and efficient pair-wise force fields for silica glass and assess their applicability for use in large scale molecular dynamic (MD) simulations of laser damage mitigation. A number of pair-wise force fields have been shown to give the random tetrahedral network of silica glass. Further, potentials obtained by fitting quantum mechanical results exhibit many of the properties of silica such as the low thermal expansion and densification. However with these potentials densification is observed at temperatures much higher than experiment. We also show that the thermodynamic melting point of β-crystobalite similarly occurs at temperatures much higher than observed experimentally. Softer empirical potentials can be constructed that do give liquid properties at experimental temperatures. However in all cases the activation energies for diffusion are lower than the experimental activation energies for viscosity.
Reduction of mare basalts by sulfur loss

Abstract Metallic Fe content and S abundance are inversely correlated in mare basalts. Either S volatilization from the melt results in reduction of Fe 2+ to Fe 0 or else high S content decreases Fe 0 activity in the melt, thus explaining the correlation. All considerations favor the model that metallic iron in mare basalts is due to sulfur loss. The Apollo 11 and 17 mare basalt melts were probably saturated with S at the time of eruption; the Apollo 12 and 15 basalts were probably not saturated. Non-mare rocks show a positive correlation of S abundance with metallic Fe content; it is proposed that this is due to the addition of meteoritic material having a fairly constant Fe 0 /S ratio. If true, metallic Fe content or S abundance in non-mare rocks provides a measure of degree of meteoritic contamination.
Capital-skill complementarity, productivity and wages: Evidence from plant-level data for a developing country

Abstract Different types of labor and capital inputs have varying productive contributions that are dependent on plant characteristics. We estimate such contributions and their underlying determinants, recognizing the interactions among labor and capital components that reflect their substitutability or complementarity, for Turkish manufacturing plants. We distinguish technical and non-technical labor, and structures, machinery and computer capital, as well as the shares of female workers and imported capital in our production function specification. We find capital-skill complementary for both machinery and computers; greater productive contributions and thus wages for skilled labor are associated with more machinery intensity and computer use. The reverse is true for unskilled labor, which is complementary only with capital structures. Our results suggest that synergies among skilled (technical) labor, computers, and machinery capital have productivity- and skilled wage-enhancing effects that could contribute to productivity convergence of developing toward developed countries, even with their differing industry and input composition.
Total Synthesis of (±)-Nisamycin

We have developed a highly convergent synthesis of the manumycin-type m-C7N-antibiotic nisamycin that is applicable to other members of this family of antibiotics. The synthesis features a three-step sequence to the epoxyquinol core that serves as a scaffold for the attachment of the polyene side chains. The eastern polyene side chain was constructed via a novel organozirconocene-mediated synthesis. Zirconocene methodology was also applied to the synthesis of the polyene side chains of asukamycin. The southern side chain of nisamycin was introduced via a Stille reaction that employed a vinyl bromo ketone, derived from an acid-sensitive bromo ketal. Pd-mediated coupling of the vinyl bromide with a stannyl TIPS ester gave TIPS-protected nisamycin that was readily converted to the natural product.
Pressure, Frictional Resistance, and Flow Characteristics of the Partially Wetted Rotating Disk

A theory of the partially wetted rotating disk is described and experimental data presented which verify the application of this theory in practical applications. Four different flow regimes may be identified according to the value of the disk Reynolds number and the spacing ratio between the disk and stationary wall. The analytical expressions for prediction of the pressure gradient developed and the frictional resistance are uniquely determined by the disk Reynolds number, spacing ratio, and the degree of wetting of the disk.
Characterization of amorphous selenium alloy detectors for x-rays and high energy nuclear radiation detection

Synthesized amorphous selenium (a-Se) alloy materials have been characterized for room temperature high-energy nuclear radiation detector and x-ray detection applications. The alloy composition has been optimized to ensure good charge transport properties and detector performance. The synthesis of a-Se (As, Cl) alloys has been carried out by thoroughly mixing zone-refined (ZR) Se (~7N) with previously synthesized a-Se(As) and a-Se(Cl) master alloys (MS). The synthesized alloys have been characterized by x-ray diffraction (XRD), glow discharge mass spectroscopy (GDMS), differential scanning calorimetry (DSC), x-ray photoelectron spectroscopy (XPS), and current-voltage (I-V) characteristics measurements. Raman spectroscopy demonstrated that the a-Se(As) master alloy samples were in metastable monoclinic Se8 states, in which seven vibrational modes are located at 40(41), 59(60), 77, 110, 133, 227(228) and 251(252) cm-1. However, a-Se(Cl) master alloy samples are in stable form of trigonal structure of Se8 ring, in which two modes at 142 and 234 cm-1 were found. Both Raman and energy dispersive spectroscopy (EDS) exhibited that a small amount of tellurium (Te) existed in a-Se (As, Cl) master alloy samples. DSC measurements showed that a-Se (Cl) MS and a-Se (As) MS samples have one melting point, located at ~219.6°C, whereas a-Se-As (0.52%)-Cl and Se- As(10.2%)-Cl(60 ppm) both possess two melting points, located at 221 and 220.3°C respectively. The a-Se alloy plate detectors have been fabricated and tested and the results showed high dark resistivity (1012 - 1013 Ω-cm) with good charge transport properties and cost-effective large-area scalability.
Stability of a premixed flame in stagnation-point flow against general disturbances

Previously, the stability of a premixed flame in a stagnation flow was discussed for a restricted class of disturbances that are self-similar to the basic undisturbed flow; thus, flame fronts with corrugations only in the cross stream direction were considered. Here, we consider a more general class of three-dimensional flame front perturbations which also permits corrugations in the streamwise direction. It is shown that, because of the stretch experienced by the flame, the hydrodynamic instability is limited only to disturbances of short wavelength. If in addition diffusion effects have a stabilizing influence, as would be the case of mixtures with Lewis number greater than one, a stretched flame could be absolutely stable. Instabilities occur when the Lewis number is below some critical value less than one. Neutral stability boundaries are presented in terms of the Lewis number, the strain rate, and the appropriate wavenumbers. Beyond the stability threshold, the two-dimensional self-similar modes always grow first. However, if disturbances of long wavelength are excluded, it is possible for the three-dimensional modes to be the least stable one. Accordingly, the pattern that will be observed on the flame front, at the onset of instability, will consist of either ridges in the direction of stretch or the more common three-dimensional cellular structure.
Expedient synthesis of α,α-difluorohomopropargylic alcohols from TIPS-difluorobromopropyne via a Zn-mediated propargylation of aldehydes and ketones

Abstract The synthesis of α,α-difluorohomopropargyl alcohols containing an alkynyl silane moiety is reported. The title compound was prepared by the reaction of the organozinc derivative of TIPS-bromodifluoropropyne with aldehydes or ketones under mild conditions and in good yields.
Links Between Young Children's Behavior and Achievement: The Role of Social Class and Classroom Composition

A growing number of studies examine the influence of classroom behavior on teaching and individual children’s behavior. However, limited work has examined the effects of classroom behavior on academic achievement. The present study used 14,537 children in 2,109 classrooms from the Early Childhood Longitudinal Study -Kindergarten Class of 1998-99 (ECLS -K) to examine the association between attention, aggressive behavior, and achievement at two levels --the child and classroom. Children with low attention, alone or in combination with aggressive behavior, made fewer gains in test scores during kindergarten. The achievement gap between children with low attention and those without was larger than those based on low-income status or race/ethnicity. Additionally, having more children in the classroom with low attention was negatively associated with achievement gains. No similar association was found for the number of children with high aggression. The authors discuss avenues for teacher training and interven...