cssi/SciSciGPT-SciSciNet huggingface dataset:
GAMMA-RAY BURST AFTERGLOW LIGHT CURVES FROM A LORENTZ-BOOSTED SIMULATION FRAME AND THE SHAPE OF THE JET BREAK

The early stages of decelerating gamma-ray burst (GRB) afterglow jets have been notoriously difficult to resolve numerically using two-dimensional hydrodynamical simulations even at very high resolution, due to the extreme thinness of the blast wave and high outflow Lorentz factors. However, these resolution issues can be avoided by performing the simulations in a boosted frame, which makes it possible to calculate afterglow light curves from numerically computed flows in sufficient detail to accurately quantify the shape of the jet break and the post-break steepening of the light curve. Here, we study afterglow jet breaks for jets with opening angles of 0.05, 0.1, and 0.2 radians decelerating in a surrounding medium of constant density, observed at various angles ranging from on-axis to the edge of the jet. A single set of scale-invariant functions describing the time evolution of afterglow synchrotron spectral break frequencies and peak flux, depending only on jet opening angle and observer angle, are all that is needed to reconstruct light curves for arbitrary explosion energy, circumburst density and synchrotron particle distribution power law slope p. These functions are presented in the paper. Their time evolutions change directly following the jet break, although an earlier reported temporary post-break steepening of the cooling break is found to have been resolution-induced. We compare synthetic light curves to fit functions using sharp power law breaks as well as smooth power law transitions. We confirm our earlier finding that the measured jet break time is very sensitive to the angle of the observer and can be postponed significantly. We find that the difference in temporal indices across the jet break is larger than theoretically anticipated and is about –(0.5 + 0.5p) below the cooling break and about –(0.25 + 0.5p) above the cooling break, both leading to post-break slopes of roughly about 0.25 – 1.3p, although different observer angles, jet opening angles and heuristic descriptions of the break introduce a wide range of temporal indices. Nevertheless, the post-break slope from our constant density interstellar medium simulations is sufficiently steep to be hard to reconcile with post-break slopes measured for the Swift sample, suggesting that Swift GRBs mostly do not explode in a homogeneous medium or that the jet breaks are hidden from view by additional physics such as prolonged energy injection or viewing angle effects. A comparison between different smooth power law fit functions shows that although smooth power law transitions of the type introduced by Harrison et al. often provide better fits, smooth power law transitions of the type introduced by Beuermann et al. or even sharp power law fits are easier to interpret in terms of the underlying model. Light curves and spectral break and peak flux evolution functions will be made publicly available online at http://cosmo.nyu.edu/afterglowlibrary.
Temperature dependence of the self‐decay rate constants of some phenoxyl radicals in aqueous solution

The Arrhenius parameters of the bimolecular rate constants for the decay of several phenoxyl radicals in aqueous solution were measured. The p-halophenoxyl radicals (F, Cl, and Br) decay in a diffusion controlled reaction as the activation energies are the same as that of diffusion of water (16 ± 1.5 kJ · mol−1). The A factors are 1012.2 ± 0.2. For alkyl and alkoxy substituted phenoxyl, slightly higher activation energies were found (19.5 − 21.9 kJ · mol−1). © 1993 John Wiley & Sons, Inc.
Generating functions for moments of the quasi-nilpotent DT-operator

We prove a recursion formula for generating functions of certain renormalizations of *-moments of the DT(@d"0,1)-operator T, involving an operation @? on formal power series and a transformation E that converts @? to usual multiplication. This recursion formula is used to prove that all of these generating functions are rational functions, and to find a few of them explicitly.
The Automorphism Group of a Simple Tracially AI Algebra

The structure of the automorphism group of a simple TAI algebra is studied. In particular, we show that \({\frac{\overline{ \rm{Inn}}(A) }{ \overline{\rm{Inn}}_{0} ( A ) }}\) is isomorphic (as a topological group) to an inverse limit of discrete abelian groups for a unital, simple, AH algebra with bounded dimension growth. Consequently, \({\frac{\overline{\rm{Inn}}(A)}{\overline{\rm{Inn}}_{0}(A) }}\) is totally disconnected.
Mild and Efficient DBU-Catalyzed Amidation of Cyanoacetates†

A mild, high-yielding, and practical protocol for the direct amidation of alkyl cyanoacetates using DBU is presented. This method eliminates the need for activation of cyanoacetic acid and/or high temperatures. It has been applied to the large-scale synthesis of CP-690,550-10 (1), a compound under development for the treatment of autoimmune diseases.
Synthesis, properties, and applications of magnetic iron oxide nanoparticles

Abstract Magnetic nanoparticles exhibit many interesting properties that can be exploited in a variety of applications such as catalysis and in biomedicine. This review discusses the properties, applications, and syntheses of three magnetic iron oxides – hematite, magnetite, and maghemite – and outlines methods of preparation that allow control over the size, morphology, surface treatment and magnetic properties of their nanoparticles. Some challenges to further development of these materials and methods are also presented.
Adaptive immune features of natural killer cells

In an adaptive immune response, naive T cells proliferate during infection and generate long-lived memory cells that undergo secondary expansion after a repeat encounter with the same pathogen. Although natural killer (NK) cells have traditionally been classified as cells of the innate immune system, they share many similarities with cytotoxic T lymphocytes. We use a mouse model of cytomegalovirus infection to show that, like T cells, NK cells bearing the virus-specific Ly49H receptor proliferate 100-fold in the spleen and 1,000-fold in the liver after infection. After a contraction phase, Ly49H-positive NK cells reside in lymphoid and non-lymphoid organs for several months. These self-renewing 'memory' NK cells rapidly degranulate and produce cytokines on reactivation. Adoptive transfer of these NK cells into naive animals followed by viral challenge results in a robust secondary expansion and protective immunity. These findings reveal properties of NK cells that were previously attributed only to cells of the adaptive immune system.
Equalization for OFDM with Multiple Delay-Doppler Paths using Conjugate Gradients with Chebyshev Preconditioning

In this paper we consider the performance of iterative solution techniques when applied to equalization for orthogonal frequency division multiplexing (OFDM) with multiple delay-doppler paths. The use of a minimum mean-squared error (MMSE) equalizer in this problem yields satisfactory bit error rate (BER) performance, but requires the inversion of a high-dimensional matrix. Reduced complexity is achieved by applying the method of conjugate gradients (CG). Proper use of preconditioning is used to accelerate convergence of CG in terms of reducing the number of steps required for good performance. We analyze the performance and efficiency of a polynomial-based preconditioner wherein an approximate inverse of the MMSE equalizer is formed from a linear combination of matrix-valued Chebyshev polynomials. The results of a simulation study are presented, demonstrating that Chebyshev-preconditioning substantially reduces the number of CG steps required to achieve performance close to that obtained with the MMSE estimator using the full inverse.
9-phenyl-3,4,4a,9a-tetrahydrotriptycene and 9-phenyl-1,2,3,4,4a,9a-hexahydrotriptycene

The structure of 9-phenyl-3,4,4a,9a-tetra­hydro­triptycene, C26H22, (I), exhibits regiochemistry consistent with a stepwise mechanism for its formation from photo­cyclo­addition of 1,3-cyclo­hexa­diene and 9-phenyl­anthracene. Bond distances involving the bridgehead C atoms are similar in (I) and the hydrogenated derivative, 9-phenyl-1,2,3,4,4a,9a-hexa­hydro­triptycene, C26H24, (II), with bonds to the quaternary-C atoms exhibiting significant elongation [1.581 (2) A in (I) and 1.585 (2) A in (II)]. The molecular geometry precludes significant σ–π overlap between the phenyl groups and the interannular bonds in both compounds, indicating that the origin of the bond lengthening is steric in nature.
Semiclassical theory of the hyperlens

We study ray dynamics inside the hyperlens, a device capable of sub-diffraction-limited far-field imaging. An analytical result for the ray trajectories inside the hyperlens is obtained using Hamiltonian optics, which offers an alternative description of the device. It is also found that the ray trajectories can exhibit a unique spiraling nature inside the device. Numerical simulations of plane wave and Gaussian beam scattering from the hyperlens confirm the semiclassical description.
Effect of pulse polarity and energy on ultrasound-induced lung hemorrhage in adult rats

The objective of this study was to further assess the role of inertial cavitation in ultrasound-induced lung hemorrhage by examining the effect of pulse polarity at a common in situ (at the lung surface) peak rarefactional pressure [pr(in situ)] and at a common in situ pulse intensity integral (PII(in situ)). A total of 60 rats was divided into three experimental groups of 20 animals per group and randomly exposed to pulsed ultrasound. The groups were exposed as follows: Group 1 to 0 degree polarity pulses (compression followed by rarefraction) at a pr(in situ) of 3.48 MPa and a PII(in situ) of 4.78 Ws/m2, group 2 to 180 degree polarity pulses (rarefraction followed by compression) at a pr(in situ) of 3.72 MPa and a PII(in situ) of 2.55 Ws/m2, and group 3 to 180 degree polarity pulses at a pr(in situ) of 4.97 MPa and a PII(in situ) of 4.79 Ws/m2. For all experimental groups, the frequency was 2.46 MHz, the exposure duration was 240 s, the pulse repetition frequency was 2.5 kHz, and the pulse duration was 0.42 micros. Six sham animals were also randomly distributed among the experimental animals. The lesion surface area and depth were determined for each rat as well as lesion occurrence (percentage of rats with lesions) per group. It was found that lesion occurrence and size correlated better with PII(in situ) than with pr(in situ), suggesting that a mechanism other than inertial cavitation was responsible for the damage.
An Elastic–Viscous–Plastic Model for Sea Ice Dynamics

The standard model for sea ice dynamics treats the ice pack as a visco‐plastic material that flows plastically under typical stress conditions but behaves as a linear viscous fluid where strain rates are small and the ice becomes nearly rigid. Because of large viscosities in these regions, implicit numerical methods are necessary for time steps larger than a few seconds. Current solution methods for these equations use iterative relaxation methods, which are time consuming, scale poorly with mesh resolution, and are not well adapted to parallel computation. To remedy this, the authors developed and tested two separate methods. First, by demonstrating that the viscous‐plastic rheology can be represented by a symmetric, negative definite matrix operator, the much faster and better behaved preconditioned conjugate gradient method was implemented. Second, realizing that only the response of the ice on timescales associated with wind forcing need be accurately resolved, the model was modified so that it reduces to the viscous‐plastic model at these timescales, whereas at shorter timescales the adjustment process takes place by a numerically more efficient elastic wave mechanism. This modification leads to a fully explicit numerical scheme that further improves the model’s computational efficiency and is a great advantage for implementations on parallel machines. Furthermore, it is observed that the standard viscous‐plastic model has poor dynamic response to forcing on a daily timescale, given the standard time step (1 day) used by the ice modeling community. In contrast, the explicit discretization of the elastic wave mechanism allows the elastic‐viscous‐plastic model to capture the ice response to variations in the imposed stress more accurately. Thus, the elastic‐viscous‐plastic model provides more accurate results for shorter timescales associated with physical forcing, reproduces viscous‐plastic model behavior on longer timescales, and is computationally more efficient overall.
Reductions and radical cyclizations of aryl and alkyl bromides mediated by NaBH4 in aqueous base

Abstract Reductions and free radical cyclizations of alkyl- and aryl bromides are effected in aqueous base by NaBH 4 in conjunction with a base-soluble dialkyltin(IV) reagent and 4,4′-azobis(4-cyanovaleric acid) (ACVA). The aryl bromides reduce at lower rates under tin-free conditions using simply NaBH 4 -ACVA.
Sodium percarbonate: A multifunctional reagent for the preparation of optically active 4-hydroxy-Δ2-isoxazolines

Abstract In this letter we report a general method for the preparation of optically active 4-hydroxy-Δ2-isoxazolines. This one-pot method employs sodium percarbonate for nitrile oxide generation, oxidation of the intermediate boronic ester substituted Δ2-isoxazoline, and cleavage of the chiral auxiliary from the final product.
Scaling laws of microactuators and potential applications of electroactive polymers in MEMS

Besides the scale factor that distinguishes the various spices fundamentally biological muscles changes little between species indicating a highly optimized system, Electroactive polymer actuators offer the closest resemblance to biological muscles however beside the large actuation displacement these materials are falling short with regards to the actuation force. As improved materials emerging it is becoming necessary to address key issues such as the need for effective electromechanical modeling and guiding parameters in scaling the actuators. In this paper, we will review the scaling laws for three major actuation mechanisms that are of relevance to micro electromechanical systems: electrostatic actuation, magnetic actuation, thermal bimetallic actuation, and piezoelectric actuation.
Ion beams in high-temperature superconductivity research☆

As previous experience would suggest, ion beams have contributed to progress in high-TC superconductivity research primarily in four ways. Ion beams have been employed for (1) analyzing composition and structural details, including phonon properties; (2) fabricating thin-film specimens; (3) modifying properties for specific applications; and (4) performing fundamental irradiation effects studies. Examples of these contributions are presented in this brief summary, and the success of different approaches is evaluated. The emphasis is on the use of intermediate (50–500 keV) and higher (0.5–10 MeV) energy ion beams; space limitations preclude covering the wide range of activities that have occurred in any detail. Substantial contributions from ion-beam techniques to the rapid progress that has occurred in high-TC research are clearly evident.
Multimode Control of a Rotating, Uniform, Cantilever Beam

An investigation was undertaken to assess the performance of a saturation controller for vibration suppression at the tip of a rotating, uniform, cantilever beam. Previous investigations have shown that saturation controllers may be effective in suppressing the vibration of nonrotating, cantilever beams. However, in those investigations, the choice of natural modes to model the beam, and justify the effectiveness of the controller, eliminated any intermodal coupling. Therefore, it is not obvious that a saturation controller will be similarly effective for rotating beams. With both theoretical and numerical analyses, it is shown that in spite of signie cant intermodal coupling, the saturation controller is remarkably effective, even at moderately high rotation speeds. Nomenclature Aij = modal centrifugal stiffening ak = modal base acceleration dij = modal damping d31 = piezoelectric constant, m/V E = Young’ s modulus, Pa H = unit step function I = area moment of inertia, m 4 kij = modal stiffness
Strategic Parenting, Birth Order and School Performance

Fueled by new evidence, there has been renewed interest about the effects of birth order on human capital accumulation. The underlying causal mechanisms for such effects remain unsettled. We consider a model in which parents impose more stringent disciplinary environments in response to their earlier-born children's poor performance in school in order to deter such outcomes for their later-born offspring. We provide robust empirical evidence that school performance of children in the National Longitudinal Study Children (NLSY-C) declines with birth order as does the stringency of their parents' disciplinary restrictions. When asked how they will respond if a child brought home bad grades, parents state that they would be less likely to punish their later-born children. Taken together, these patterns are consistent with a reputation model of strategic parenting.
Olefin Metathesis in Cyclic Ether Formation. Direct Conversion of Olefinic Esters to Cyclic Enol Ethers with Tebbe-Type Reagents

Department of Chemistry, The Scripps Research Institute 10666 North Torrey Pines Road, La Jolla, California 92037 Department of Chemistry and Biochemistry UniVersity of California, San Diego 9500 Gilman DriVe, La Jolla, California 92093 ReceiVed October 17, 1995 The olefin metathesis reaction1 is rapidly emerging as a powerful tool in organic synthesis.2 Of particular interest are ring forming metathesis reactions catalyzed by transition metal complexes, several elegant examples of which have recently appeared.3 Despite the successes of this general approach to ring construction, much remains to be improved in terms of scope, convenience, and generality. In this communication we report a new strategy, based on the olefin metathesis reaction, for the generation of cyclic enol ethers directly from olefin esters4 using the Tebbe5 or the Petasis reagents.6 Scheme 1 shows the general concept7 for the envisioned Tebbe-reagent-mediated transformation of olefinic esters of type I to cyclic enol ethers of type VI. Thus it was anticipated that the initially formed enol ether II would react with a second molecule of the Tebbe reagent to afford the titanacyclobutane III, fragmentation of which would then lead to titanium alkylidene IV. Intramolecular reaction of IV was then expected to lead to titanacyclobutane V, whose regioselective fragmentation as shown should allow an entry to the desired cyclic enol ethers VI via olefin metathesis. Implementation of this strategy using olefinic ester 1 leads to the formation of cyclic enol ether 3 via the initially formed methylenation product 2 in 71% overall yield (Scheme 2). The intermediacy of compound 2 was proven by isolation and full spectral characterization followed by conversion to 3 under the influence of the Tebbe reagent. The generality and scope of this new process was investigated by employing a variety of substrates. As illustrated in Table 1, the reaction can deliver a series of sixand seven-membered cyclic enol ethers in good yields (entries 1-3 and 10-12, respectively). In addition to these findings, the important observation of the open-chain products shown in entries 6-9 (Table 1) was made. These hydroxy exomethylenic compounds are presumably obtained by sequential hydrolysis and olefination of the initially formed cyclic enol ethers.8 Apparently the lability of the enol ether products depends on their precise environment and the reaction conditions, a circumstance that
Economic Systems and Economic Growth

In a planned economy, state monopoly ensures that economies of scale are exploited. However, state monopoly could not commit to reward its workers. Anticipating this, individuals will exert less effort. In a market economy, competition among firms ensures that higher effort from workers will be rewarded. However, competition means that economies of scale are not fully exploited. Per capita output growth is generated by continuous adoption of new technologies substituting labor for capital. Growth rate in a market economy is higher than that in a planned economy when the incentive to exert effort is relatively more important.
Storage stability studies of fuels derived from shale and petroleum

Abstract Fuel storage degradation was monitored in the early stages by laser light scattering of developing particles at ambient temperature. Degradation products obtained by heat stressing (at 80–120 °C) of fuels enriched with specific heteroatomic compounds were analysed by n.m.r., FT-i.r. and e.s.c.a. It was found that 2,5-dimethylpyrrole (DMP) is especially deleterious to fuel stability, followed in effect by alkyl-substituted quinolines, pyridines and indoles. The oxygen and nitrogen contents of the sediments from shale-derived jet and diesel fuels which contain DMP are almost twice the corresponding values of petroleum-DMP sediment. Oxygen is incorporated in the sediments as carboxylate and carbonyl groups. P.m.r. spectra of several soluble sediments show a wide range of aromatic signals, indicating that the sediment contains much polycyclic material. Deposits formed in the presence of DMP and thiophenol contain significant amounts of nitrogen and sulphur.
Parallel hypothesis verification

Abstract The verification of identity and pose hypotheses in model-based three-dimensional (3D) object recognition systems can involve a time-consuming image rendering operation followed by pixel-level comparison of the input and rendered images. In situations where many such hypotheses need to be verified, exploitation of inherent data-parallelism between hypotheses and their corresponding object models offers the potential for increased efficiency of the overall object recognition system. A prototype system is described for distribution of hypotheses and the accompanying rendering tasks to individual processors in a loosely-coupled computing environment, and excellent performance improvements are demonstrated over a single-processor implementation.
A High-Resolution VLA Study of M17-UC1

Using the Very Large Array, we have observed the H66α radio recombination line (RRL) emission at 1.3 cm and the H52α RRL emission at 7 mm toward the ultracompact H II region M17-UC1 and the nearby arc-shaped structure to the east. The angular resolution of the data is 1''-2''. The compact H II region (deconvolved size ~06 or 0.006 pc) is one of a number of H II regions with broad (≥35 km s-1) RRLs. The line parameters of the nearby arc of ionized emission (hereafter the Arc), about 1'' or 0.01 pc to the east of UC1, are remarkably constant over an area of 165 × 3'' (0.17 pc × 0.03 pc). The derived LTE electron temperature from the H66α line (T) is 6600 K in M17-UC1 and 8200 K in the Arc region. H2O maser emission at 1.3 cm from the region of M17-UC1 was observed in the D array with a beam of 4''. Observations of the H2O maser emission toward M17-UC1 reveal four masers within 30'' of M17-UC1; two of these sources were previously known. We discuss the region near M17-UC1 as an example of shock-induced star formation consisting of a hot, young, massive star surrounded by ionized material, perhaps resulting from a stellar wind outflow. We compare M17-UC1 with the six other known examples of broad-line RRL emission from ultracompact H II regions.
The dynamics of relationship marketing in international sponsorship networks

Purpose – While various scholars have identified relationship marketing objectives as a rationale for sports sponsorship engagement, analytic investigations of the implications of a relational approach to the corporate sponsorship network have been slow to materialize. The purpose of this paper is to advance the discussion of sponsorship as a means of industrial sports marketing towards a network conceptualization, which can be dissected from both the perspective of the sponsoring firms and that of the sponsored enterprise.Design/methodology/approach – This paper employs an illustrative case‐based approach to the application of network analysis tools as a means of exploring the relationship marketing dynamics of corporate sponsorship portfolios.Findings – Several research propositions and applicable network analytics are presented within the context of Formula One racing team sponsorship portfolios. The concepts of network range, density, power, growth, and social capital are explored in regards to their ...
Cryogenic positive expulsion bladders

Abstract NASA-LeRC in-house and contractual experimental programs were conducted to determine the cryogenic flexibility of single and multiple plies of thin polymeric films at −320 and −423°F (77 and 20°K). Results of cryogenic flexibility or “twist-flex” testing showed that thin Mylar films are the most flexible of the films tested. The relation between cryogenic cycle life, film thickness, and the number of plies for Mylar film are reported at −320 and −423°F (77 and 20°K). Results of contractual testing of Mylar, Kapton, and polyethylene film bladders at −423°F (20°K) are summarized. Bladder material combinations showing the lowest helium gas porosity after 25 liquid hydrogen cycles are Mylar and an organic filament-reinforced polyethylene film laminate and Kapton/Nomex-Nylon.
A reexamination of option values implicit in callable Treasury bonds

Abstract Longstaff (1992) and Edleson, Fehr, and Mason (1993) examine option values implicit in callable Treasury bonds and report a significant puzzle: implied option values are frequently negative. Using an alternative approach, we reexamine this issue and find that implied option values are generally positive, and, in contrast to previous studies, instances of option values sufficiently negative to overcome the bid-ask spread are rare. We explain the findings in other studies by showing that the method used may lead to the appearance of a negative option value when the true value is positive.
Credit Ratings and Taxes: The Effect of Book–Tax Differences on Ratings Changes

This paper examines whether credit analysts utilize the information contained in the difference between book and taxable income in analyzing a firm’s credit risk. Increased book–tax differences may be informative for credit rating agencies as they may signal decreased earnings quality or changes in the firm’s off–balance sheet financing. Results suggest a significant negative association between positive changes in book–tax differences and ratings changes. This evidence is consistent with large positive changes in book–tax differences signaling decreased earnings quality and/or increased off–balance sheet financing. We also find that large negative changes in book–tax differences result in less favorable rating changes, consistent with these changes signaling decreased earnings quality. In additional analyses, we find that the association between changes in book–tax differences and rating changes is attenuated for high–tax-planning firms (e.g., where book–tax differences more likely reflect tax planning than decreased earnings quality).
Neutron Star Accretion in a Supernova

An estimate can be made of the effect of a central mass on an explosion through the study of self-similar blast waves in a medium having an inverse-square-of-r density profile, as is approximately the case in the inner core of the progenitor of SN 1987A; its parameters are such that the nucleon density is substantially constant within the shock front. In SN explosions with a massive envelopes, the core material is decelerated by its interaction with the envelope, and a reverse shock wave propagates back to the center. 42 refs.
Metalorganic Chemical Vapor Deposition of Ferroelectric Pb(Zr,Ti)O3 Thin Films

Ferroelectric Pb(ZrxT1–x)O3, films were successfully and reproducibly deposited by both hot–wall metalorganic chemical vapor deposition (MOCVD) and cold-wall MOCVD. One of the important problems associated with the MOCVD techniques is the selection of ideal precursors. After an intensive investigation for the most suitable precursors for MOCVD PZT films, the safe and stable precursors, namely lead tetramethylheptadione [Pb(thd)2], zirconium tetramethylheptadione [Zr(thd)4], and titanium ethoxide [Ti(OEt)4], were chosen. The films were deposited at temperatures as low as 550°C and were single-phase perovskite in the as-deposited state. Also, the films were smooth, specular, crack-free, and uniform, and adhered well to the substrates. The stoichiometry of the films can be easily controlled by varying the individual precursor temperature and/or the flow rate of the carrier gas. Auger electron spectroscopic (AES) depth profile showed good compositional uniformity through the thickness of the films. The AES spectra also showed no carbon contamination in the bulk of the films. As-deposited films were dense and showed uniform and fine grains (≅0.1 μm).The optical properties of the films on the sapphire disks showed high refractive index (n= 2.413) and low extinction coeflicient (k= 0.0008) at a wavelength of 632.8 nm. The PZT (82/18) film annealed at 600°C showed a spontaneous polarization of 23.3 μC/cm2 and a coercive field of 64.5 kV/cm.
Multi-height Scattering Phase Shifts from Sunspots and Phase Differences Between Photospheric Heights with SDO/HMI and AIA Data

Following Couvidat (Solar Phys. 282, 15, 2013), we analyze data from the Helioseismic and Magnetic Imager (HMI) and the Atmospheric Imaging Assembly (AIA) instruments onboard the Solar Dynamics Observatory. Doppler velocity and continuum intensity at 6173 A as well as intensity maps at 1600 A and 1700 A are studied on 14 active regions and four quiet-Sun regions at four heights in the solar photosphere. A Hankel–Fourier analysis is performed around these regions of interest. Outgoing–ingoing scattering phase shifts at a given atmospheric height are computed, as well as ingoing–ingoing and outgoing–outgoing phase differences between two atmospheric heights. The outgoing–ingoing phase shifts produced by sunspots show little dependence on measurement height, unlike the acoustic power reduction measured in Couvidat (2013). Phenomena happening above the continuum level, like acoustic glories, appear not to have a significant effect on the phases. However, there is a strong dependence on sunspot size, line-of-sight magnetic flux, and intensity contrast. As previously suggested by other groups, the region of wave scattering appears both horizontally smaller and vertically less extended than the region of acoustic power suppression, and occurs closer to the surface. Results presented here should help refine theoretical models of acoustic wave scattering by magnetic fields. Ingoing–ingoing phase differences between two measurement heights are also computed and show a complex pattern highly dependent on atmospheric height. In particular, a significant sensitivity of AIA signals to lower chromospheric layers is shown. Finally, ingoing–ingoing minus outgoing–outgoing phase differences between various measurement heights are discussed.
Azimuthal Spread of the Avalanche in Proportional Chambers

The angular distribution of the avalanche around the anode wire in the gas proportional counter is determined by measuring the distribution of positive ions arriving on cathode strips surrounding the anode wire for each single event. The shape and width of the distribution depend on such factors as the gas gain, the anode diameter, the counting gas and the primary ionization density. Effects of these factors are studied systematically, and their importance for practical counter applications is discussed.
Highly Enantioselective Amination of α-Substituted α-Cyanoacetates with Chiral Catalysts Accessible from Both Quinine and Quinidine

The catalytic construction of nitrogen-substituted quaternary stereocenters is an important and challenging task in asymmetric synthesis. In this paper, we describe the use of 6‘-OH-modified cinchona alkaloids that are accessible from either quinine or quinidine for the development of a highly enantioselective amination of α,α-disubstituted carbonyl compounds that is suitable for the creation of nitrogen-substituted quaternary stereocenters in either the R or S configuration.
Results and conjectures on simultaneous core partitions

An n-core partition is an integer partition whose Young diagram contains no hook lengths equal to n. We consider partitions that are simultaneously a-core and b-core for two relatively prime integers a and b. These are related to abacus diagrams and the combinatorics of the affine symmetric group (type A). We observe that self-conjugate simultaneous core partitions correspond to the combinatorics of type C, and use abacus diagrams to unite the discussion of these two sets of objects. In particular, we prove that 2n- and (2mn+1)-core partitions correspond naturally to dominant alcoves in the m-Shi arrangement of type C"n, generalizing a result of Fishel-Vazirani for type A. We also introduce a major index statistic on simultaneous n- and (n+1)-core partitions and on self-conjugate simultaneous 2n- and (2n+1)-core partitions that yield q-analogs of the Coxeter-Catalan numbers of type A and type C. We present related conjectures and open questions on the average size of a simultaneous core partition, q-analogs of generalized Catalan numbers, and generalizations to other Coxeter groups. We also discuss connections with the cyclic sieving phenomenon and q,t-Catalan numbers.
Wigner Random Matrices with Non-Symmetrically Distributed Entries

We show that the spectral radius of an N× N random symmetric matrix with i.i.d. bounded centered but non-symmetrically distributed entries is bounded from above by 2 σ + o(N−6/11+e), where σ2 is the variance of the matrix entries and e is an arbitrary small positive number. Our bound improves the earlier results by Z. Furedi and J. Komlos (1981), and Van Vu (2005).
Clinical significance of plasma endostatin in acute myeloid leukemia/myelodysplastic syndrome

BACKGROUND Endostatin, a C-terminal fragment of collagen XVIII, is an endogenous angiogenesis inhibitor. While endostatin is being investigated for its usefulness in treating solid tumors, its significance in hematologic malignancies is unknown. METHODS The authors evaluated plasma endostatin (PE) levels using an enzyme linked immunoassay in 71 patients with acute myeloid leukemia (AML) and 43 patients with myelodysplastic syndrome (MDS), and correlated PE with various clinical parameters. RESULTS There was no significant difference in the median PE level between AML/MDS patients and the normal controls. Nevertheless, patients who achieved complete remission (CR) had a significantly lower median PE level compared to those who did not. In multivariate analysis, PE was found to be a significant (P = 0.03) predictor of overall survival (OS) with adjustment of the other baseline covariates, including patient age, history of antecedent hematologic disorders, and the use of protective environments. The prognostic value of PE was also evaluated by dividing MDS/AML patients into high and low PE groups using the median PE level of normal controls as the cut-off. The authors found that patients in the high PE group survived for a significantly shorter time than those patients in the low PE group. CONCLUSIONS PE is a useful prognostic predictor of CR and OS for AML/MDS patients. The mechanism underlying the association between high PE and poor clinical outcome is unclear, although it may be related to the possible PE reflection of tumor burden. Cancer 2002;94:14–7. © 2002 American Cancer Society.
Postoperative opioid-induced respiratory depression: a closed claims analysis.

Background:Postoperative opioid-induced respiratory depression (RD) is a significant cause of death and brain damage in the perioperative period. The authors examined anesthesia closed malpractice claims associated with RD to determine whether patterns of injuries could guide preventative strategies
The Fibonacci Numbers -- Exposed More Discretely

(2003). The Fibonacci Numbers—Exposed More Discretely. Mathematics Magazine: Vol. 76, No. 3, pp. 182-192.
Nanoscale studies of segregation at coherent heterophase interfaces in α-Fe based systems

Heterophase interfaces are characterized with respect to atomic-scale local compositions in two α-Fe-based alloy systems by three-dimensional atom probe microscopy. The proximity histogram method is utilized for determining the compositions of the precipitates, the matrix phase and the Gibbsian interfacial excess of solute. Suitable methods to measure segregation in multicomponent systems at heterophase interfaces independent of the position of the dividing interface are discussed. Very little Sb segregates to the heterophase interface between coherent plate-shaped moybdenum nitride precipitates, which are <1 nm thick, and the α-Fe matrix: the relative interfacial excess of Sb is only 0.12 ± 0.1 nm−2. This is in sharp contrast to the interfacial excess of 7 ± 3 nm−2 for molybdenum nitride plates that have grown to 2–10 nm thick (or 20–30 nm in diameter for spheroidal precipitates) with a semicoherent interface with misfit dislocations, as reported earlier. Small coherent Cu-rich precipitates with a metastable bcc structure in an α-Fe matrix exhibit interfacial segregation of Ni and Mn at their interfaces with excesses of 1.47 ± 0.43 and 0.95 ± 0.31 nm−2, respectively. Copyright © 2004 John Wiley & Sons, Ltd.
THE MAPPING CLASS GROUP OF A DISK WITH INFINITELY MANY HOLES

A left orderable completely metrizable topological group is exhibited containing Artin's braid group on infinitely many strands. The group is the mapping class group (rel boundary) of the closed unit disk with a sequence of interior punctures converging to the boundary. This resolves an issue suggested by work of Dehornoy.
An introduction to computed chaining

A hashing function, H(x), is a transformation from a key value x to an address. Since such transformations may produce the same address for distinct keys, hashing functions lead to collisions in the address space. Many methods for resolving hashing collisions have been reported [1, 2]. Direct chaining and open addressing are the two basic collision-resolution methods. This paper presents a form of hybrid hashing, computed chaining, which is better than a previously described hybrid hashing procedure called pseudochaining [3]. In certain situations it is also better than other collision procedures.
Applications of Boolean matrices to the analysis of flow diagrams

Any serious attempt at automatic programming of large-scale digital computing machines must provide for some sort of analysis of program structure. Questions concerning order of operations, location and disposition of transfers, identification of subroutines, internal consistency, redundancy and equivalence, all involve a knowledge of the structure of the program under study, and must be handled effectively by any automatic programming system.
A Study of the Dynamics of Dust from the Kuiper Belt: Spatial Distribution and Spectral Energy Distribution

The dust produced in the Kuiper belt (KB) spreads throughout the solar system, forming a dust disk. We numerically model the orbital evolution of KB dust and estimate its equilibrium spatial distribution and its brightness and spectral energy distribution (SED), assuming graybody absorption and emission by the dust grains. We show that the planets modify the KB disk SED, so potentially we can infer the presence of planets in spatially unresolved debris disks by studying the shape of their SEDs. We point out that there are inherent uncertainties in the prediction of structure in the dust disk, owing to the chaotic dynamics of dust orbital evolution imposed by resonant gravitational perturbations of the planets.
Bayesian reconstruction of binary media with unresolved fine-scale spatial structures

Abstract We present a Bayesian technique to estimate the fine-scale properties of a binary medium from multiscale observations. The binary medium of interest consists of spatially varying proportions of low and high permeability material with an isotropic structure. Inclusions of one material within the other are far smaller than the domain sizes of interest, and thus are never explicitly resolved. We consider the problem of estimating the spatial distribution of the inclusion proportion, F(x), and a characteristic length-scale of the inclusions, δ, from sparse multiscale measurements. The observations consist of coarse-scale (of the order of the domain size) measurements of the effective permeability of the medium (i.e., static data) and tracer breakthrough times (i.e., dynamic data), which interrogate the fine scale, at a sparsely distributed set of locations. This ill-posed problem is regularized by specifying a Gaussian process model for the unknown field F(x) and expressing it as a superposition of Karhunen–Loeve modes. The effect of the fine-scale structures on the coarse-scale effective permeability i.e., upscaling, is performed using a subgrid-model which includes δ as one of its parameters. A statistical inverse problem is posed to infer the weights of the Karhunen–Loeve modes and δ, which is then solved using an adaptive Markov Chain Monte Carlo method. The solution yields non-parametric distributions for the objects of interest, thus providing most probable estimates and uncertainty bounds on latent structures at coarse and fine scales. The technique is tested using synthetic data. The individual contributions of the static and dynamic data to the inference are also analyzed.
Plume‐induced topography and geoid anomalies and their implications for the Tharsis rise on Mars

The topography and geoid anomalies produced from an upwelling plume are sensitive to the depth of plume buoyancy, D p , and elastic lithospheric thickness, T e , both of which control the degree of compensation. We formulated spherically axisymmetric convection models of mantle plumes with temperature- and pressure-dependent viscosity to dynamically determine D p and T e and the resulting topography and geoid anomalies from the plume. From 10 cases with different Rayleigh number, activation energy, and activation volume, we determined Te ranging from 100 km to 180 km and D p that is approximately twice T e . The ratio of geoid to topography, R G/T , from these plume models is either negative or slightly positive (<0.03) at wavelengths that are most relevant to the Tharsis rise (low harmonics from degrees 2 to 4). The modeled R G/T is significantly smaller than that observed for the Tharsis rise, suggesting that Tharsis is unlikely to be dynamically supported.
Elliptical Galaxy Dynamics

,(a b)/a with a and b the major- and minor-axis lengths. Hubble understood that the observed ellipticity was only a lower limit to the true elongation because of the unknown orientation of a galaxy’s “polar axis”; he called this uncertainty “serious, but unavoidable.” Nevertheless, he was able to compute an estimate of the frequency function of intrinsic shapes by assuming that elliptical galaxies were oblate spheroids with random orientations (Hubble 1926). Hubble’s remarks remain nearly as valid today as they were six decades ago. Classification of elliptical galaxies is still based almost entirely on their luminosity distributions, and although Hubble’s analysis of the intrinsic shape distribution has been considerably refined, we still know little of a definite nature about the three-dimensional shapes of these systems. An important shift in our understanding of elliptical galaxies took place in 1975, following the discovery that most ellipticals rotate significantly more slowly than expected for a fluid body with the same flattening (Bertola & Capaccioli 1975). Elliptical galaxies were revealed to be “hot” stellar systems, in which most of the support against gravitational collapse comes from essentially random motions rather than from ordered rotation. Two questions immediately arose from these observations: what produces the observed flattenings, and, given that rotation plays only a minor role, are elliptical galaxies axisymmetric or fully triaxial? Binney (1978) suggested that the flattenings were due in large part to anisotropic velocity distributions and noted that triaxial figures were no less likely than axisymmetric ones. His suggestion was quickly followed up by Schwarzschild (1979, 1982), who showed that self-consistent triaxial models could be constructed by the superposition of time-averaged orbits. The phenomenon of triaxiality has since remained cen
Impact of Residual Extractives on Lignin Determination in Kraft Pulps

Abstract The amount of residual extractives in kraft pulps and oxygen‐delignified pulps and their impact on the usual methods of lignin determinations were investigated. The lignin analyses investigated were kappa number and Klason lignin in conjunction with acid‐soluble lignin. The species investigated were loblolly pine, white birch, and aspen. In the hardwoods, significant amounts of extractives remained after kraft pulping and oxygen delignification. These residual extractives in the hardwood pulps had an impact on the lignin determination, more so on the acid lignin method than kappa number. For an accurate lignin determination, solvent extraction of hardwood kraft and oxygen‐delignified pulp is needed, but not for softwood pulps.
Gold-Catalyzed One-Step Practical Synthesis of Oxetan-3-ones from Readily Available Propargylic Alcohols

A general solution for the synthesis of various oxetan-3-ones is developed. This reaction uses readily available propargylic alcohols as substrates and proceeds without the exclusion of moisture or air (“open flask”). Notably, oxetan-3-one, a highly valuable substrate for drug discovery, can be prepared in one step from propargyl alcohol in a fairly good yield. The facile formation of the strained oxetane ring provides strong support for the intermediacy of α-oxo gold carbenes. This safe and efficient generation of gold carbenes via intermolecular alkyne oxidation offers a potentially general entry into α-oxo metal carbene chemistry without using hazardous diazo ketones.
Poor Association between Hyperglycemia at Arrival and Clinical Outcomes in Acute Stroke Patients Treated With Tissue-Type Plasminogen Activator

outcome. Design Consecutive rt-PA-treated acute ischaemic stroke patients presenting to four emergency departments were analysed. Associations of initial blood glucose and survival to hospital discharge, symptomatic intracerebral haemorrhage, any form of intracerebral haemorrhage, and disability at hospitaldischargeweredetermined.Potentiallyconfounding factors of age, National Institutes of Health Stroke Scale, and smoking were analysed by univariate logistic regression and those with Po0.3 included in the multivariate model. Study Outcome In 268 patients, initial glucose values ranged from 62 to 507mg/dl (mean 131). Elevated glucose at arrival was not significantly associated with any adverse clinical outcomes. A trend towards higher mortality in hyperglycaemic patients (odds ratio 1.71 per 100mg/dl increase in glucose, 95% confidence interval 0.92–3.13, P 50.08) was seen, but is of unclear significance, and was not corroborated by effects on discharge disability, symptomatic intracerebral haemorrhage or intracerebral haemorrhage. Conclusions Thrombolytic-treated stroke patients with hyperglycaemiaatpresentationdidnothavesignificantlyworse outcomesthanothersinthiscohort.Thesedatafailtoconfirm previously described associations seen in similarly sized studies. Further study of these associations and their magnitude are necessary to better define the relationship between serum glucose and outcome in thrombolytic-treated acute ischaemic stroke.