cssi/SciSciGPT-SciSciNet huggingface dataset:
Studies of the mechanisms of bradykinin generation in hereditary angioedema plasma

Background Factor XII–dependent bradykinin formation is thought to be responsible for the swelling associated with the various forms of C1 inhibitor deficiency, and complement activation is augmented during attacks of swelling. Objectives To further elucidate the interactions of the kinin-forming cascade that lead to complement activation during attacks of swelling and to determine whether fibrinolysis is augmented as well. Methods We compared spontaneous and kaolin-induced activation of normal plasma with the plasma of patients with hereditary angioedema. Results Hereditary angioedema plasma demonstrated augmented factor XII activation, production of factor XIIf, prekallikrein activation, and high-molecular-weight kininogen cleavage, and, as a result, bradykinin formation was markedly increased. Baseline levels of C4a and plasmin-α 2 antiplasmin complexes increased, and, on activation with kaolin, levels increased further. Conclusions All parameters indicative of activation of the bradykinin-forming cascade are activated in hereditary angioedema plasma vs normal plasma. Production of factor XIIf, demonstrated for the first time in whole plasma, may be responsible for C1 activation based on C4a production. The factor XII–dependent fibrinolytic cascade is also activated.
Stereoselective dioxygenation of enoates

Abstract The auxiliary-directed reaction of singlet oxygen with tiglate esters furnishes an asymmetric synthesis of 3-hydroperoxy-2-methylidene butenoates. Although previous reports have suggested that s-cis enoate conformers undergo preferential oxygenation relative to the s-trans conformers, our results suggest that both conformers are reactive and that the modest stereoselectivity is based upon a conformational equilibrium favoring the s-trans conformer.
PATENTS, LICENSING, AND MARKET STRUCTURE IN THE CHEMICAL INDUSTRY

Abstract The strategies of rent appropriation and industry structure are inter-dependent. How firms use patents depends upon industry structure, and in turn, affects industry structure. In the 19th century, market leaders in the chemical industry combined patents and secrecy to deter entry. Within cartels, patents were used to stabilize cartels and organize technology licensing. The role of patents changed in the less concentrated post World War II markets. In bulk organic chemicals and petrochemicals, chemical producers use licensing as an important means of generating revenue from process innovations. The increased importance of technology licensing is closely related to the emergence of a class of specialized process design and engineering firms that have played an important role in the development and diffusion of process innovations.
Reporting the impact of inferior vena cava perforation by filters.

BackgroundPerforation of the inferior vena cava by filters struts is a known complication. The goal of our review is to assess the impact of inferior vena cava perforation by filters based on an open, voluntary national database.MethodsWe reviewed 3311 adverse events of inferior vena cava filters reported in Manufacturer and User Facility Device Experience database from January 2000 to June 2011. Outcomes of interest were incidence of inferior vena cava perforation, type of filter, clinical presentation, and management of the perforation, including retrievability rates.ResultsThree hundred ninety-one (12%) cases of inferior vena cava perforation were reported. The annual distribution of inferior vena cava perforation was 35 cases (9%), varying from seven (2%) to 70 (18%). A three-fold increment in the number of adverse events related to inferior vena cava filters has been noted since 2004. Wall perforation as an incidental finding was the most common presentation (N = 268, 69%). Surrounding organ involvem...
Isolated, Massive Supergiants near the Galactic Center

We have carried out a pilot project to assess the feasibility of using radio, infrared, and X-ray emission to identify young, massive stars located between 1 and 25 pc from the Galactic center. We first compared catalogs compiled from the VLA, Chandra, and 2MASS. We identified two massive, young stars: the previously identified star that is associated with the radio H II region H2 and a newly identified star that we refer to as CXOGC J174516.1-290315. The infrared spectra of both stars exhibit very strong Brγ and He I lines and resemble those of massive supergiants that have evolved off of the main sequence but not yet reached the Wolf-Rayet phase. We estimate that each star has a bolometric luminosity 106 L☉. These two stars are also associated with bright mid-infrared sources from the MSX survey, although the origin of this emission is uncertain. Likewise, the detection of these two sources in X-rays is surprising because stars at similar evolutionary states are not uniformly bright X-ray sources. Therefore, we suggest that both stars are in binary systems that contain either OB stars whose winds collide with those of the luminous supergiants or compact objects that are accreting from the winds of the supergiants. We also identify X-ray emission from a nitrogen-type Wolf-Rayet star and place upper limits on the X-ray luminosities of three more evolved, massive stars that previously have been identified between 1 and 25 pc from Sgr A*. Finally, we briefly discuss the implications that future searches for young stars will have for our understanding of the recent history of star formation near the Galactic center.
Unconditionally stable concurrent procedures for transient finite element analysis

A new class of algorithms for transient finite element analysis which is amenable to an efficient implementation in parallel computers is proposed. The suitability of the method for parallel computation stems from the fact that, given an arbitrary partition of the finite element mesh, each subdomain in the partition can be processed over a time step independently and simultaneously with the rest. Both element-by-element and coarse partitions of the mesh are discussed. For the former, the proposed algorithms are shown to have the structure of an explicit scheme. In particular, no global equation solving effort is involved in the update procedure. However, in contrast to explicit schemes the proposed algorithms are shown to be unconditionally stable over a certain range of the algorithmic parameters. In structural dynamics problems, good accuracy is obtained with a constant time step integration. For heat conduction problems accuracy limitations suggest the use of a step-changing technique. When this is done, numerical tests indicate the good behavior of the method. The case in which the mesh is partitioned into a small number of subdomains, typically as many as processors in the computer, is also explored in detail. Good accuracy is obtained over a wide range of time steps. Finally, extensions to second- and higher-order accuracy methods are discussed.
Is It Round? Spectropolarimetry of the Type II-p Supernova 1999em

We present the first multiepoch spectropolarimetry of a Type II plateau supernova (SN II-P), with optical observations of SN 1999em on days 7, 40, 49, 159, and 163 after discovery. These data are used to probe the geometry of the electron scattering atmosphere before, during, and after the plateau phase, which ended roughly 90 days after discovery. Weak continuum polarization with an unchanging polarization angle (θ ≈ 160°) is detected at all epochs, with p ≈ 0.2% on day 7, p ≈ 0.3% on days 40 and 49, and p ≈ 0.5% in the final observations. Distinct polarization modulations across strong line features are present on days 40, 49, 159, and 163. Uncorrected for interstellar polarization (which is believed to be quite small), polarization peaks are associated with strong P Cygni absorption troughs, and nearly complete depolarization is seen across the Hα emission profile. The temporal evolution of the continuum polarization and sharp changes across lines indicate polarization intrinsic to SN 1999em. When modeled in terms of the oblate, electron scattering atmospheres of Hoflich, the observed polarization suggests an asphericity of at least 7% during the period studied. The temporal polarization increase may indicate greater asphericity deeper into the ejecta. We discuss the implications of asphericity on the use of Type II-P supernovae as primary extragalactic distance indicators through the expanding photosphere method (EPM). If asphericity produces directionally dependent flux and peculiar galaxy motions are characterized by σ = 300 km s-1, it is shown that the agreement between previous EPM measurements of SNe II and distances to the host galaxies predicted by a linear Hubble law restricts mean SN II asphericity to values less than 30% (3 σ) during the photospheric phase.
A new jet algorithm based on the k-means clustering for the reconstruction of heavy states from jets

A jet algorithm based on the k-means clustering procedure is proposed which can be used for the invariant-mass reconstruction of heavy states decaying to hadronic jets. The proposed algorithm was tested by reconstructing e+e-→tt→6 jets and e+e-→W+W-→4 jets processes at \(\sqrt{s}=500\,\mathrm{GeV}\) using a Monte Carlo simulation. It was shown that the algorithm has a reconstruction efficiency similar to traditional jet-finding algorithms, and leads to 25% and 40% improvement of the top-quark and W mass resolution, respectively, compared to the kT (Durham) algorithm. In addition, it is expected that the peak positions measured with the new algorithm have smaller systematical uncertainty.
Experimental Analysis of a Waveguide Pressure Measuring System

An infinite-line probe is commonly used to measure unsteady pressure in high-temperature environments while protecting the pressure transducer. In this study, an existing theoretical model is used to derive the response of a waveguide pressure measuring system. An ambient temperature centrifugal compressor rig acts as an experimental source of fluctuating pressure. The compressor is operated at different discrete rotational speeds, and the blade-passing frequencies are used to obtain frequency response data. In the experiments, pressure waves attenuated at a rate faster than that predicted by the theoretical model for a 0.322 m (12 in.) sensor offset. Furthermore, the decay in the magnitude of the pressure oscillations accelerated at blade-passing frequencies above 9 kHz. A unique contribution of this study is to show that whereas the experimentally observed overall attenuation is broadly consistent with the theoretical predictions, pressure oscillations corresponding to individual blade passages may be disproportionally attenuated.
Theory of spin transfer phenomena in magnetic metals and semiconductors

Abstract We propose a general theory of the spin-transfer effects that occur when current flows through inhomogeneous magnetic systems. Our theory does not rest on an appeal to conservation of total spin, can assess whether or not current-induced magnetization precession and switching in a particular geometry will occur coherently, and can estimate the efficacy of spin-transfer when spin–orbit interactions are present. We illustrate our theory by applying it to a toy-model twodimensional-electron-gas ferromagnet with Rashba spin–orbit interactions.
Recognition of natural scenes from global properties: Seeing the forest without representing the trees

Human observers are able to rapidly and accurately categorize natural scenes, but the representation mediating this feat is still unknown. Here we propose a framework of rapid scene categorization that does not segment a scene into objects and instead uses a vocabulary of global, ecological properties that describe spatial and functional aspects of scene space (such as navigability or mean depth). In Experiment 1, we obtained ground truth rankings on global properties for use in Experiments 2–4. To what extent do human observers use global property information when rapidly categorizing natural scenes? In Experiment 2, we found that global property resemblance was a strong predictor of both false alarm rates and reaction times in a rapid scene categorization experiment. To what extent is global property information alone a sufficient predictor of rapid natural scene categorization? In Experiment 3, we found that the performance of a classifier representing only these properties is indistinguishable from human performance in a rapid scene categorization task in terms of both accuracy and false alarms. To what extent is this high predictability unique to a global property representation? In Experiment 4, we compared two models that represent scene object information to human categorization performance and found that these models had lower fidelity at representing the patterns of performance than the global property model. These results provide support for the hypothesis that rapid categorization of natural scenes may not be mediated primarily though objects and parts, but also through global properties of structure and affordance.
Engineering catalyst surfaces with metal carbonyl clusters

Abstract This article reviews recent progress in the application of metal carbonyl clusters to preparation of supported catalysts and suggests opportunities for future research. Catalysis by surface-bound metal carbonyl clusters and catalysis by structurally simple supported metals derived by decarbonylation of surface-bound clusters have been achieved. A catalytic cycle for ethene hydrogenation by triosmium clusters on silica has been proposed, and molecular metal clusters have been stabilized on basic metal oxides under conditions of CO hydrogenation catalysis. In these examples, molecular metal clusters are the only organometallic surface species detected by in situ spectroscopy. Surface-bound metal carbonyl clusters have been used to prepare well-defined catalytic entities, ensembles of supported mononuclear complexes and supported metal atom clusters, which retain the nuclearity of the precursor. The latter are structurally simple supported metals which provide an opportunity to explore structure sensitivity in catalysis by nano-scale metal clusters. Of technological importance, metal carbonyl clusters and mononuclear organometallics are being used to engineer multi-layer catalysts with advanced architectures and novel catalytic properties.
Evolution of gluon TMD at low and moderate x

We study how the rapidity evolution of gluon transverse momentum dependent distribution changes from nonlinear evolution at small x ≪ 1 to linear double-logarithmic evolution at moderate x ~ 1.
Regioselective synthesis of trifluoromethylated pyrazoles by selective protection of trifluoromethyl‐β‐diketones

1,1,1-Trifluoropentane-2,4-dione was selectively protected by treatment with pyrrolidine to give 6. The reaction of 6 with arylhydrazines gave 5 exclusively. The structural assignment for 5 was confirmed by quenching the dianion of 8 with ethyl trifluoroacetate.
Construction of Highly Substituted Stereodefined Dienes by Cross‐Coupling of α‐Allenic Acetates

The assembly of highly substituted dienes remains a challenge for organic chemistry. This work represents a strategyfor the construction of highly substituted 1,3-dienes by meansof a Tsuji–Trost cross coupling between α-allenic acetates and organozinc reagents. The reaction is high yielding, and installs a trisubstituted olefin with E/Z selectivities up to 95:5 favoring the (E) product. A cheap, commercially available palladium precatalyst and a ligand are used to control theE/Z selectivity. Furthermore, an interesting reversal in selectivity is noted in which appropriate choice of ligand may be used to control the outcome of the reaction and favor the (Z) product. Thirteen examples are described, highlighting the substrate scope of the reaction. It is hoped that the straightforward reaction conditions and high selectivity will make this reaction of broad use in natural product chemistry. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Tunable coupled-mode dispersion compensation and its application to on-chip resonant four-wave mixing

We propose and demonstrate mode coupling as a viable dispersion compensation technique for phase-matched resonant four-wave mixing (FWM). We demonstrate a dual-cavity resonant structure that employs coupling-induced frequency splitting at one of three resonances to compensate for cavity dispersion, enabling phase matching. Coupling strength is controlled by thermal tuning of one cavity enabling active tuning of the resonant frequency matching. In a fabricated silicon microresonator, we show an 8 dB enhancement of seeded FWM efficiency over the noncompensated state. The measured FWM has a peak wavelength conversion efficiency of −37.9 dB across a free spectral range (FSR) of 3.334 THz (∼27 nm), which is, to the best of our knowledge, the largest in a silicon microresonator to demonstrate FWM to date. This form of dispersion compensation can be beneficial for many devices, including wavelength converters, parametric amplifiers, and widely detuned photon-pair sources. Apart from compensating dispersion, the proposed mechanism can alternatively be utilized in an otherwise dispersionless resonator to counteract the detuning effect of self- and cross-phase modulation on the pump resonance during FWM, thereby addressing a fundamental issue in the performance of light sources such as broadband optical frequency combs.
Comparison of VLBI Radio-Core and X-Ray Flux Densities of Extragalactic Radio Sources

The relation between compact radio core and X-ray emission in extragalactic radio sources, suggested by Worral et al. (1987) and Kembhavi et al. (1986), is investigated by comparing the X-ray flux densities observed in 56 extragalactic radio sources with the Einstein Observatory with the compact radio-core flux densities derived from published VLBI maps for these radio sources. It was found that the radio to X-ray spectral index distribution had a small dispersion, whereas the log-log plot of the flux densities showed no correlation. This implies that the basic level of X-ray emission is determined by the radio-core emission, but that the exact value depends on other parameters.
The STAR Forward GEM Tracker

Abstract The STAR collaboration is preparing a forward tracking detector upgrade, the Forward GEM Tracker (FGT), to provide fundamental studies of the proton spin structure and dynamics in high-energy polarized proton–proton collisions at RHIC at BNL. The FGT is based on triple-GEM technology employing the industrial production of GEM foils by Tech-Etch Inc. and a laser-etched two-dimensional readout board manufactured by Compunetics Inc. The FGT project has completed an extensive R&D program of industrially produced GEM foils at Tech-Etch Inc. in comparison to GEM foils produced at CERN based on optical measurements and 55Fe source and testbeam measurements of a triple-GEM prototype detector using 10 × 10 cm 2 GEM foils. The FGT project requires large GEM foils which are currently being tested.
New developments in thermally stable polymers

Advances in high-temperature polymers since 1985 are discussed with the emphasis on the chemistry. High-temperature polymers refer to materials that exhibit glass-transition temperatures greater than 200 C and have the chemical structure expected to provide high thermooxidative stability. Specific polymers or series of polymers were selected to show how the chemical structure influences certain properties. Poly(arylene ethers) and polyimides are the two principal families of polymers discussed. Recent work on poly(arylene ethers) has concentrated on incorporating heterocyclic units within the polymer backbone. Recent polyimide work has centered on the synthesis of new polymers from novel monomers, several containing the trifluoromethyl group strategically located on the molecule. Various members in each of these polymer families display a unique combination of properties, heretofore unattainable. Other families of polymers are also briefly discussed with a polymer from an AB maleimidobenzocyclobutene exhibiting an especially attractive combination of properties.
Public versus Private Borrowing: A Theory with Implications for Bankruptcy Reform

Abstract A model is presented in which firms optimally finance investment with both public and private debt. The two instruments are perfect substitutes, except that private debt can easily be renegotiated in insolvency states while public debt cannot. The option to renegotiate is beneficial ex post, as it allows the firm to avoid inefficient liquidation, but ex ante it may worsen asset substitution. The welfare effects of alternative bankruptcy regimes are then compared, taking into account that firms modify their financing decision in response to the regime change. Some suggestions for reforming Chapter 11 of the U.S. bankruptcy code are presented. Journal of Economic Literature Classification Numbers: G32, G33, K2.
Multiloop control of a nanopositioning mechanism for ultraprecision beam steering

Beam steering accuracy is critical to the successful operation of optical communications systems, especially those which take place over extreme length scales, such as for an interstellar spacecraft. In this paper, a novel beam steering mechanism and several control system approaches for ultra-precision beam steering are discussed. The beam steering mechanism is a nanopositioning device which utilizes a parallel cantilever configuration and a piezoelectric actuator to obtain extremely high positioning accuracy with minimal parasitic errors. A robust motion controller is presented for this mechanism which is designed to compensate for modeling uncertainty. This controller is intended for use with feedback from the nanopositioner’s built-in capacitance probe. Due to the need to track the trajectory of the steered beam, two additional control approaches are presented which combine the robust motion controller with additional feedback for the actual beam displacement. These multi-loop control approaches provide a level of robustness to thermal effects and vibrations which could not be obtained from a single sensor and feedback loop. Simulation results are provided for each of the control designs.
Diaphyseal bone formation in murine tibiae in response to knee loading

Mechanical stimulation is critical for bone architecture and bone mass. The aim of this study was to examine the effects of mechanical loads applied to the knee. The specific question was whether loads applied to the tibial epiphysis would enhance bone formation in the tibial diaphysis. In C57/BL/6 mice, loads of 0.5 N were applied for 3 min/day for 3 days at 5, 10, or 15 Hz. Bone samples were harvested 13 days after the last loading. The strains were measured 13±2 mu strains at 5 Hz in the diaphysis. The histomorphometric data in the diaphysis clearly showed enhanced bone formation. First, compared with nonloaded control the cross-sectional cortical area was increased by 11% at 5 Hz and 8% at 10 Hz (both P<0.05). Second, the cortical thickness was elevated by 12% at 5 Hz (P<0.01) and 8% at 10 Hz (P<0.05). Third, mineralizing surface (MS/BS), mineral apposition rate (MAR), and bone formation rate (BFR/BS) were increased at 5 Hz (P<0.01 for MS/BS; P<0.001 for MAR and BFR/BS) and at 10 Hz (P<0.05 for MS/BS; P<0.01 for MAR and BFR/BS). Bone formation was enhanced more extensively in the medial side than the lateral or the posterior side. The results reveal that knee loading is an effective means to enhance bone formation in the tibial diaphysis in a loading frequency-dependent manner without inducing significant in situ strain at the site of bone formation.
Preparation and Biological Actions of N-2,2,2-Trifluoroethyl-2-(3,4-dihydroxyphenyl) ethylamine

N-2,2,2-Trifluoroethyl-2-(3,4-dihydroxyphenyl)ethylamine was synthesized and compared to N-ethyl-2-(3,4-dihydroxyphenyl)-ethylamine and dopamine for activity on adenylate cyclase in the rat striatum. Both dopamine and N-ethyl-2-(3,4-dihydroxyphenyl)ethylamine stimulated adenylate cyclase activity in a dose-dependent fashion. The N-trifluoroethyldopamine analog at 1 × 10−4 M induced a weak effect. The compounds were evaluated further by studying their relaxant effects in isolated rabbit renal and ear arteries. Both the N-ethyl- and N-trifluoroethyldopamine analogs produced a relaxant effect but demonstrated no selectivity for dopamine receptors.
Lie n-racks

Abstract In this Note, we introduce the category of Lie n -racks and generalize several results known on racks. In particular, we show that the tangent space of a Lie n -rack at the neutral element has a Leibniz n -algebra structure.
Spin and charge distribution symmetry dependence of stripe phases in two-dimensional electron systems confined to wide quantum wells

Measurements in clean two-dimensional electron systems confined to wide GaAs quantum wells in which two electric subbands are occupied reveal an unexpected rotation of the orientation of the stripe phase observed at a half-filled Landau level. Remarkably, the reorientation is sensitive to the spin of the half-filled Landau level and the symmetry of the charge distribution in the quantum well.
A network pricing game for selfish traffic

The success of the Internet is remarkable in light of the decentralized manner in which it is designed and operated. Unlike small scale networks, the Internet is built and controlled by a large number of disparate service providers who are not interested in any global optimization. Instead, providers simply seek to maximize their own profit by charging users for access to their service. Users themselves also behave selfishly, optimizing over price and quality of service. Game theory provides a natural framework for the study of such a situation. However, recent work in this area tends to focus on either the service providers or the network users, but not both. This paper introduces a new model for exploring the interaction of these two elements, in which network managers compete for users via prices and the quality of service provided. We study the extent to which competition between service providers hurts the overall social utility of the system.
Terahertz harmonic generation in graphene

We show that charge carrier transport in graphene exhibits sharp resonances in the presence of spatially and temporarily modulated scattering. Resonances occur when the period of an applied a–c field corresponds to the time taken by quasi-ballistic carriers to drift over a spatial scattering period, provided the latter is shorter than the distance taken by carriers to emit an optic phonon. We show that such system can be achieved with interdigitated gates energized with an a–c bias on graphene layers. Gate separation and fields to achieve ballistic transport would result in resonances in the terahertz range, with the generation of higher harmonics characterized by large Q-factors, which are tunable with gate spacing.
Federal Trade Commission v. Actavis, Inc. and reverse-payment or pay-for-delay settlements

An imminent US Supreme Court ruling should resolve one of the thorniest legal issues facing pharmaceutical companies today.
Wavelet transform coefficient histogram-based image enhancement algorithms

This paper proposes two image enhancement algorithms that are based on utilizing histogram data gathered from wavelet transform domain coefficients. Computer simulations demonstrate that combining the spatial method of histogram equalization with the logarithmic transform domain coefficient histograms achieves a much more balanced enhancement, which outperforms classical histogram equalization algorithms.
SOME EXACT ANALYTICAL SOLUTIONS OF PLANETARY ENTRY

Approximate analytical solutions of entry into a planetary atmosphere at constant lift-drag ratio have been presented by Gazley, Chapman, Alien and Eggers, and Loh. Constant liftdrag ratio entry dictates variable angles of inclination. On the other hand, variable lift-drag ratio entry has been discussed by Lees, Grant, and Loh. A few approximate analytical solutions of variable lift-drag ratio entry have been given by Lohi exact analytical solutions of entry into a planetary atmosphere have not been presented before. It is the purpose of this paper to present some exact analytical solutions obtained recently. When minor terms of the exact solutions are neglected, the exact solutions presented here reduce precisely to those approximate solutions presented previously by Loh for variable lift-drag ratio entry.
Exact analysis of the M/M/k/setup class of Markov chains via recursive renewal reward

The M/M/k/setup model, where there is a penalty for turning servers on, is common in data centers, call centers, and manufacturing systems. Setup costs take the form of a time delay, and sometimes there is additionally a power penalty, as in the case of data centers. While the M/M/1/setup was exactly analyzed in 1964, no exact analysis exists to date for the M/M/k/setup with $$k>1$$ k > 1 . In this paper, we provide the first exact, closed-form analysis for the M/M/k/setup and some of its important variants including systems in which idle servers delay for a period of time before turning off or can be put to sleep. Our analysis is made possible by a new way of combining renewal reward theory and recursive techniques to solve Markov chains with a repeating structure. Our renewal-based approach uses ideas from renewal reward theory and busy period analysis to obtain closed-form expressions for metrics of interest such as the transform of time in system and the transform of power consumed by the system. The simplicity, intuitiveness, and versatility of our renewal-based approach makes it useful for analyzing Markov chains far beyond the M/M/k/setup. In general, our renewal-based approach should be used to reduce the analysis of any 2-dimensional Markov chain which is infinite in at most one dimension and repeating to the problem of solving a system of polynomial equations. In the case where all transitions in the repeating portion of the Markov chain are skip-free and all up/down arrows are unidirectional, the resulting system of equations will yield a closed-form solution.
Calculation of ionization in direct-frequency comb spectroscopy

Direct-frequency comb spectroscopy (DFCS) is currently the highest-resolution absolute frequency spectroscopic technique known. In general, one does DFCS by scanning the repetition rate, ${f}_{\mathrm{rep}}$, of a comb laser and measuring fluorescence from the excited states of the species under study. The technique has already been successfully characterized by a theoretical model that starts with the optical Bloch equations and, with a few simplifying assumptions converts them into linear coupled iterative equations. In the present work we build on that successful model to predict the characteristics of the ion yield from photoionization by the comb laser, as a function of ${f}_{\mathrm{rep}}$. We show that the ion spectrum yields the same atomic structure as the fluorescence spectra, but with greater efficiency.
A Large Dark Matter Core in the Fornax Dwarf Spheroidal Galaxy

We use measurements of the stellar velocity dispersion profile of the Fornax dwarf spheroidal galaxy to derive constraints on its dark matter distribution. Although the data are unable to distinguish between models with small cores and those with cusps, we show that a large 1 kpc dark matter core in Fornax is highly implausible. Irrespective of the origin of the core, reasonable dynamical limits on the mass of the Fornax halo constrain its core radius to be no larger than ~700 pc. We derive an upper limit of rcore 300 pc by demanding that the central phase-space density of Fornax not exceed that directly inferred from the rotation curves of low-mass spiral galaxies. Furthermore, if the halo is composed of warm dark matter, then phase-space constraints force the core to be quite small in order to avoid conservative limits from the Ly? forest power spectrum, rcore 85 pc. We discuss our results in the context of the idea that the extended globular cluster distribution in Fornax can be explained by the presence of a large ~1.5 kpc core. A self-consistent core of this size would be drastically inconsistent with the expectations of standard warm or cold dark matter models and would also require an unreasonably massive dark matter halo, with Vmax 200 km s-1.
DWARF GALAXY FORMATION WITH H2-REGULATED STAR FORMATION

We describe cosmological galaxy formation simulations with the adaptive mesh refinement code Enzo that incorporate a star formation prescription regulated by the local abundance of molecular hydrogen. We show that this H{sub 2}-regulated prescription leads to a suppression of star formation in low-mass halos (M{sub h} {approx} 4, alleviating some of the dwarf galaxy problems faced by theoretical galaxy formation models. H{sub 2} regulation modifies the efficiency of star formation of cold gas directly, rather than indirectly reducing the cold gas content with 'supernova feedback'. We determine the local H{sub 2} abundance in our most refined grid cells (76 proper parsec in size at z = 4) by applying the model of Krumholz, McKee, and Tumlinson, which is based on idealized one-dimensional radiative transfer calculations of H{sub 2} formation-dissociation balance in {approx}100 pc atomic-molecular complexes. Our H{sub 2}-regulated simulations are able to reproduce the empirical (albeit lower z) Kennicutt-Schmidt relation, including the low {Sigma}{sub gas} cutoff due to the transition from atomic to molecular phase and the metallicity dependence thereof, without the use of an explicit density threshold in our star formation prescription. We compare the evolution of the luminosity function, stellarmore » mass density, and star formation rate density from our simulations to recent observational determinations of the same at z = 4-8 and find reasonable agreement between the two.« less
X-ray-pumped Cr,Nd:GSGG laser

It has been demonstrated that x rays alone can be used to pump a 1061 nm Cr,Nd:GSGG laser. Lasing action has been observed when the laser rod absorbs greater than 27 krad of 2 MeV x rays. The laser cavity consists of a corner cube and an output mirror with a reflectivity of 67%. The x rays are delivered in a 20 ns pulse, and laser action is observed several microseconds after the x ray pulse. This delay suggests that chromium is important in the laser pumping process since it is known that an excited chromium ion takes about 10 microseconds to transfer its energy to a neodymium ion.
Iridium-Catalyzed Hydrocarboxylation of 1,1-Dimethylallene: Byproduct-Free Reverse Prenylation of Carboxylic Acids

Exposure of carboxylic acids 1a−12a to commercially available 1,1-dimethylallene in the presence of substoichiometric quantities of an iridium catalyst prepared in situ from [Ir(cod)Cl]2 and BIPHEP provides the corresponding 1,1-dimethylallyl (reverse prenyl) esters 1b−12b in 74−92% isolated yield. This protocol represents the first branch-regioselective allene hydrocarboxylation. Stoichiometric byproducts are not generated in this process and protecting groups are not required for alcohols, phenols, and indolic amines.
Infrared observations of the planetary nebula NGC 7027.

An infrared spectrometer has been constructed with a resolution of Δλ/λ≈0.02 for observations in the wavelength range from 2.8 to 15 μ using a gallium-doped germanium bolometer (Low, 1961) as the radiation-sensitive element. Observations of the planetary nebula NGC 7027 were made with this instrument in May and June 1967 at the Catalina Observing Station of the University of Arizona. It was discovered that there was a measurable continuum flux from this object in the wavelength range from 7.5–14 μ that compared in value with the strength of stellar radiation from a Lyr (A0) at about λ=9 μ. These observations are described in detail elsewhere (Gillett et al.,1967).
Random growth models with polygonal shapes

We consider discrete-time random perturbations of monotone cellular automata (CA) in two dimensions. Under general conditions, we prove the existence of half-space velocities, and then establish the validity of the Wulff construction for asymptotic shapes arising from finite initial seeds. Such a shape converges to the polygonal invariant shape of the corresponding deterministic model as the perturbation decreases. In many cases, exact stability is observed. That is, for small perturbations, the shapes of the deterministic and random processes agree exactly. We give a complete characterization of such cases, and show that they are prevalent among threshold growth CA with box neighborhood. We also design a nontrivial family of CA in which the shape is exactly computable for all values of its probability parameter.
Convenient divergent strategy for the synthesis of TunePhos-type chiral diphosphine ligands and their applications in highly enantioselective Ru-catalyzed hydrogenations.

A convenient, divergent strategy for the synthesis of a series of modular and fine-tunable C3-TunePhos-type chiral diphosphine ligands and their applications in highly efficient Ru-catalyzed asymmetric hydrogenations were explored. Up to 97 and 99% ee values were achieved for the enantioselective synthesis of β-methyl chiral amines and α-hydroxy acid derivatives, respectively.
How do western abyssal currents cross the equator

Previous investigations of upper ocean currents on a β-plane have shown that it is quite difficult for a parcel of fluid to cross the equator in the open ocean. Boundary currents sometimes can cross the equator, but even this crossing is not easily achieved. The main barrier for equatorial crossing of inviscid western boundary currents is the presence of a front on the open ocean side (Nof, 1990, Deep-Sea Research, 37, 853–875). One-and-a-half and 212 layer models are used to examine how this frontal blocking constraint is modified by bottom topography. Both models show that some topographic features, such as the Mid-Atlantic Ridge, may entirely relax the frontal blocking constraint. The single layer crossing is modeled in terms of a heavy double-fronted inertial current (overlaid by a stagnant infinitely deep upper layer) flowing northward in a parabolic channel. Analytic solutions show that the current's position “flips” as it crosses the equator, it is situated next to the left flank of the channel (i.e. the western boundary) in the southern hemisphere and next to the right flank (i.e. the eastern part of the channel corresponding to the western side of the the mid-ocean ridge) in the northern hemisphere. With the aid of the above model, a 212 layer model, which contains an additional intermediate current above the core, is considered. It is found that the nonfrontal southward (or northward) intermediate flow crosses the equator and remains adjacent to the western boundary. In contrast, the deep frontal flow underneath again “flips” from the left to the right boundary as it crosses the equator. Possible application of this theory to the dense Antarctic Bottom Water (AABW) and the Lower North Atlantic Deep Water (LNADW) is discussed.
Restriction Properties of Annulus SLE

For κ∈(0,4], a family of annulus SLE(κ;Λ) processes were introduced in (Zhan in arXiv: 1004.1865v1 ) to prove the reversibility of whole-plane SLE(κ). In this paper we prove that those annulus SLE(κ;Λ) processes satisfy a restriction property, which is similar to that for chordal SLE(κ). Using this property, we construct n≥2 curves crossing an annulus such that, when any n−1 curves are given, the last curve is a chordal SLE(κ) trace.
Highly Efficient and Enantioselective Iridium-Catalyzed Asymmetric Hydrogenation of N-Arylimines

A catalytic method employing the cationic iridium-(S c ,R p )-DuanPhos [(1R,1'R,2S,2'S)-2,2'-ditert-butyl-2,2',3,3'-tetrahydro-1H,1'H-1,1'-biisophosphindole] complex and BARF {tetrakis[3,5-bis(trifluoromethyl)phenyl]borate) counterion effectively catalyzes the enantioselective hydrogenation of acyclic N-arylimines with high turnover numbers (up to 10,000 TON) and excellent enantioselectivities (up to 98% ee), achieving the practical synthesis of chiral secondary amines.
Interest-rate derivatives and bank lending

Abstract We study the relationship between bank participation in derivatives contracting and bank lending for the period 30 June 1985 through the end of 1992. Since 1985 commercial banks have become active participants in the interest-rate derivative products markets as end-users, or intermediaries, or both. Over much of this period significant changes were made in the composition of bank portfolios. We find that banks using interest-rate derivatives experience greater growth in their commercial and industrial (C&I) loan portfolios than banks that do not use these financial instruments. This result is consistent with the model of Diamond (Review of Economic Studies 51, 1984, 393–414) which predicts that intermediaries' use of derivatives enables increased reliance on their comparative advantage as delegated monitors.
Incomplete Markets, Transitory Shocks, and Welfare

Abstract Although equilibrium allocations in models with incomplete markets are generally not Pareto-efficient, it is often argued that quantitative welfare losses from missing assets are small when time horizons are long and shocks are transitory. In this paper we use a computational analysis to show that even in the simplest infinite horizon model without aggregate uncertainty welfare losses can be substantial. Furthermore we show that in this model welfare losses from incomplete markets do not necessarily disappear when one considers calibrations of the model in which agents become very patient. We argue that when the economic model is calibrated to higher frequency data, the period persistence of negative income shocks must increase as well. In this case the welfare loss of incomplete markets remains constant even as agents' rate of time preference tends to one. Journal of Economic Literature Classification Numbers: D52, D58, D60.
Convergence to approximate Nash equilibria in congestion games

Abstract We study the ability of decentralized, local dynamics in non-cooperative games to rapidly reach an approximate (pure) Nash equilibrium. Our main result states that for symmetric congestion games in which the cost function associated with each resource satisfies a “bounded jump” condition, convergence to an e-Nash equilibrium occurs within a number of steps that is polynomial in the number of players and e − 1 . We show moreover that this result holds under a variety of conventions governing the move orders among the players, including the minimal liveness assumption that no player is indefinitely blocked from moving. We also prove that in the generalized setting where players have different “tolerances” e i , the number of moves a player makes before equilibrium is reached depends only on his associated e i , and not on those of other players. Finally, we show that polynomial time convergence holds even when a constant number of resources have arbitrary cost functions.
Ambulatory Blood Pressure, Microalbuminuria, And Autonomic Neuropathy In Adolescents With Type 1 Diabetes

OBJECTIVE—To examine the relationship between 24-h blood pressure (BP) measurements, urinary albumin excretion rates, and autonomic neuropathy (AN) in adolescents with type 1 diabetes. RESEARCH DESIGN AND METHODS—A total of 31 patients with microalbuminuria (MA), 20 patients with intermittent MA (I-MA) and 11 patients with persistent MA (P-MA) were identified from the diabetes clinics at two major Australian tertiary care pediatric hospitals. Two control groups were used, one consisted of 19 age-, sex-, and diabetes duration-matched adolescents with normoalbuminuria (NA), and the other consisted of 46 age and sex-matched nondiabetic control subjects. A medical history and physical examination were followed by a series of noninvasive tests of cardiovascular and pupillary autonomic function and then by 24-h ambulatory blood pressure monitoring (ABPM). RESULTS—ABPM showed an incremental increase in all BP parameters from nondiabetic control subjects through subjects with NA. A parallel incremental increase in diurnal and nocturnal ambulatory heart rates was also evident. Subjects with MA had significantly reduced pupillary adaptation to darkness compared with nondiabetic subjects and subjects with NA. The above results paralleled an incremental increase in HbA(1c) levels in adolescents with type 1 diabetes from subjects with NA to subjects with P-MA. CONCLUSIONS—Higher 24-h BP values and evidence of subclinical signs of AN are present before P-MA develops and may have important implications for timing the introduction of treatments designed to prevent or retard the microvascular complications of type 1 diabetes in adolescents.
On abstract representations of the groups of rational points of algebraic groups and their deformations

In this paper, we continue our study, begun in an earlier paper, of abstract representations of elementary subgroups of Chevalley groups of rank ≥2. First, we extend the methods to analyze representations of elementary groups over arbitrary associative rings and, as a consequence, prove the conjecture of Borel and Tits on abstract homomorphisms of the groups of rational points of algebraic groups for groups of the form SLn,D, where D is a finite-dimensional central division algebra over a field of characteristic 0. Second, we apply the previous results to study deformations of representations of elementary subgroups of universal Chevalley groups of rank ≥2 over finitely generated commutative rings.
CESIUM FLUORIDE CATALYZED TRIFLUOROMETHYLATION OF ESTERS, ALDEHYDES, AND KETONES WITH (TRIFLUOROMETHYL)TRIMETHYLSILANE

The low reactivity of carboxylic esters toward (trifluoromethyl)trimethylsilane (TMS−CF3) was investigated. A universal cesium fluoride catalyzed procedure for nucleophilic trifluoromethylation was developed. At room temperature (25 °C), with catalytic amounts of cesium fluoride, carboxylic esters were found to react to give the silyl ether intermediates, which afforded the trifluoromethyl ketones after hydrolysis. Sulfonic, sulfinic, and selenic esters also show good reactivity, giving novel trifluoromethylated compounds. The trifluoromethylation method was also applied to aldehydes and ketones, which were transformed to trifluoromethyl silyl ether intermediates and afforded trifluoromethylated alcohols in excellent yields after acid hydrolysis. Ethylene glycol dimethyl ether was used as solvent for solid or high boiling substrates, and benzonitrile was used for the low boiling substrates.
ON THE ROAD TO MORE REALISTIC GALAXY CLUSTER SIMULATIONS: THE EFFECTS OF RADIATIVE COOLING AND THERMAL FEEDBACK PRESCRIPTIONS ON THE OBSERVATIONAL PROPERTIES OF SIMULATED GALAXY CLUSTERS

Flux-limited X-ray surveys of galaxy clusters show that clusters come in two roughly equally proportioned varieties: cool core clusters (CCs) and non-cool core clusters (NCCs). In previous work, we have demonstrated using cosmological N-body + Eulerian hydrodynamic simulations that NCCs are often consistent with early major merger events that destroy embryonic CCs. In this paper we extend those results and conduct a series of simulations using different methods of gas cooling and of energy and metal feedback from supernovae, where we attempt to produce a population of clusters with realistic central cooling times, entropies, and temperatures. We find that the use of metallicity-dependent gas cooling is essential to prevent early overcooling, and that adjusting the amount of energy and metal feedback can have a significant impact on observable X-ray quantities of the gas. We are able to produce clusters with more realistic central observable quantities than have previously been attained. However, there are still significant discrepancies between the simulated clusters and observations, which indicates that a different approach to simulating galaxies in clusters is needed. We conclude by looking toward a promising subgrid method of modeling galaxy feedback in clusters that may help to ameliorate the discrepancies between simulations and observations.