cssi/SciSciGPT-SciSciNet huggingface dataset:
The Transition from the First Stars to the Second Stars in the Early Universe

We observe a sharp transition from a singular, high-mass mode of star formation to a low-mass-dominated mode, in numerical simulations, at a metallicity of 10-3 Z☉. We incorporate a new method for including the radiative cooling from metals into adaptive mesh refinement hydrodynamic simulations. Our results illustrate how metals, produced by the first stars, led to a transition from the high-mass star formation mode of Population III stars to the low-mass mode that dominates today. We ran hydrodynamic simulations with cosmological initial conditions in the standard ΛCDM model, with metallicities, from zero to 10-2 Z☉, beginning at redshift z = 99. The simulations were run until a dense core forms at the center of a 5 × 105 M☉ dark matter halo, at z ~ 18. Analysis of the central 1 M☉ core reveals that the two simulations with the lowest metallicities, Z = 0 and 10-4 Z☉, contain one clump with 99% of the mass, while the two with metallicities Z = 10-3 and 10-2 Z☉ each contain two clumps that share most of the mass. The Z = 10-3 Z☉ simulation also produced two low-mass protostellar objects with masses between 10-2 and 10-1 M☉. Gas with Z ≥ 10-3 Z☉ is able to cool to the temperature of the cosmic microwave background (CMB), which sets a lower limit to the minimum fragmentation mass. This suggests that the second-generation stars produced a spectrum of lower mass stars but were still more massive, on average, than stars formed in the local universe.
O( d, d, Z) transformations as automorphisms of the operator algebra

Abstract We implement the O ( d , d , Z ) transformations of T-duality as automorphisms of the operator algebras of conformal field theories. This extends these transformations to arbitrary field configurations in the deformation class.
Dislocation Dynamics Simulations of Junctions in Hexagonal Close-Packed Crystals

The formation and strength of dislocations in the hexagonal closed-packed material are studied through dislocation junctions and the critical stress required to completely break them. Dislocation dynamics calculations of junctions are compared to an analytical line tension approximation in order to verify the simulations. Results show agreements between the models. Also the critical shear stress necessary to break a short and a long dislocation junction is computed numerically. Unzipping envelopes are mapped out for these junctions to describe their stability regions as functions of resolved shear stresses on the glide planes. The example of two non-coplanar binary dislocation junctions with slip systems [2 -1 -1 0] (0 1 -1 0) and [-1 2 -1 0] (0 0 0 1) corresponding to a prismatic and basal slip respectively is chosen to verify and validate our implementation.
Carboranyl thymidine analogues for neutron capture therapy

Neutron capture therapy (NCT) is a binary radio-chemotherapeutic modality for the treatment of cancer. A major focus of NCT-related research is the development of novel tumor-selective agents that serve as the chemical component in NCT. Thymidine analogues substituted with a boron-containing carborane cluster at the N3 position, designated 3CTAs (3-carboranyl thymidine analogues), constitute one class of these new improved NCT agents. Their chemical, structural and biological properties are discussed in this Feature Article.
Astrophysics of Young Star Binaries

This paper describes our study of the astrophysics of individual components in close pre-main-sequence binaries. We observed both stars in 17 systems, located in four nearby star-forming regions, using low-resolution (R = 760) infrared spectroscopy and photometry. For 29 components we detected photospheric absorption lines and were able to determine spectral type, extinction, K-band excess, and luminosity. The other five objects displayed featureless or pure emission line spectra. In ~50% of the systems, the extinction and K-band excess of the primary stars dominate those of the secondaries. Masses and ages were determined for these 29 objects by placing them on the H-R diagram, overlaid with theoretical pre-main-sequence tracks. Most of the binaries appear to be coeval. The ages span 5 ? 105 to 1 ? 107 yr. The derived masses range from the substellar, 0.06 M?, to 2.5 M?, and the mass ratios from M2/M1 = 0.04 to 1.0. Fourteen stars show evidence of circumstellar disks. The K-band excess is well correlated with the K-L color for stars with circumstellar material.
Electrophysical properties of GeSexTe1−x single crystals grown by physical vapor transport (PVT)†

The room temperature composition dependences of the lattice parameters, mass density, thermopower, Hall constant, carrier concentration and mobility, and electrical conductivity of GeSexTe1−x (x=0.1 − 0.4) single crystals grown by the Physical Vapor Transport (PVT) method, indicate that the crystals are non-stoichiometric degenerate semiconductors having p-type conductivity. The main lattice defects in this compound are germanium vacancies. The effects of selenium content on the electrical properties of GeSexTe1−x single crystals are explained qualitatively based on the character of the energy levels and on the non-stoichiometric property of this compound. Elektrophysikalische Eigenschaften von durch Sublimation gewachsenen GeSexTe1−x-Mischkristallen. Die Abhangigkeiten der Gitterkonstanten, Massendichte, Hall-Konstante, der Konzentration und Beweglichkeit der Ladungstrager, und der elektrischen Leitfahigkeit von GeSexTe1−x(x=0,1 − 0,4) Einkristallen, gezuchtet mittels PVT, zeigen an, das die Kristalle nicht-stochiometrische, entartete Halbleiter mit p-Typ-Leitfahigkeit sind. Die Hauptgitterdefekte sind Germanium-Leerstellen. Die Einflusse des Selengehaltes auf die elektrischen Eigenschaften der GeSexTe1−x-Einkristalle sind qualitativ erklarbar mit Hilfe des Energiediagramms und der nicht-stochiometrischen Eigenschaft dieser Verbindung.
USE OF PREDICTIVE PERFORMANCE MODELING DURING LARGE-SCALE SYSTEM INSTALLATION

In this paper we describe an important use of predictive application performance modeling - the validation of measured performance during a new large-scale system installation. Using a previously-developed and validated performance model for SAGE, a multidimensional, 3D, multi-material hydrodynamics code with adaptive mesh refinement, we were able to help guide the stabilization of the first phase of the Los Alamos ASCI Q supercomputer. We review the salient features of an analytical model for this code that has been applied to predict its performance on a large class of Tera-scale parallel systems. We describe the methodology applied during system installation and upgrades to establish a baseline for the achievable "real" performance of the system. We also show the effect on overall application performance of certain key subsystems such as PCI bus speed and multi-rail networks. We show that utilization of predictive performance models is also a powerful system debugging tool.
On the regular variation of ratios of jointly Fréchet random variables

We provide a necessary and sufficient condition for the ratio of two jointly α-Frechet random variables to be regularly varying. This condition is based on the spectral representation of the joint distribution and is easy to check in practice. Our result motivates the notion of the ratio tail index, which quantifies dependence features that are not characterized by the tail dependence index. As an application, we derive the asymptotic behavior of the quotient correlation coefficient proposed in Zhang (Ann Stat 36(2):1007–1030, 2008) in the dependent case. Our result also serves as an example of a new type of regular variation of products, different from the ones investigated by Maulik et al (J Appl Probab 39(4):671–699, 2002).
Structure of the X-Ray Emission from the Jet of 3C 273

We present images from four Chandra observations of the quasar 3C 273. The zeroth order images from two grating observations using the AXAF CCD Imaging Spectrometer (ACIS-S) detector are used to examine the structure and spectrum of the jet. The jet has at least four distinct features which are not resolved in previous observations. Using jet feature nomenclature based on HST observations, we find that knot Al is very bright in X-rays. We have measured the X-ray spectrum of this X-ray knot for the first time, obtaining a photon index of 1.36 +/- 0.11 and a flux density of 37 +/- 4 nJy at 1 keV. Combining this measurement with lower frequency data shows that a pure synchrotron model can fit the spectrum of knot Al from 4 GHz to 5 keV (over nine decades in energy) without a change of spectral slope. Knot A2 is also detected and is somewhat blended with knot B1 but synchrotron emission is not likely to explain the X-ray emission due to the spectral turnover observed in the optical-UV band. No other knots are clearly detected but there is an indication of weak emission from the eastern portion of knot H3. near the "head," which is radio-bright. There is diffuse flux which extends from 14 arcsec to 20 arcsec which shows curvature that is comparable to the optical flux found by Bahcall, et al.
Noninvasive electron microscopy with interaction-free quantum measurements

We propose the use of interaction-free quantum measurements with electrons to eliminate sample damage in electron microscopy. This might allow noninvasive molecular-resolution imaging. We show the possibility of such measurements in the presence of experimentally measured quantum decoherence rates and using a scheme based on existing charged particle trapping techniques.
Crater degradation in the Martian highlands: Morphometric analysis of the Sinus Sabaeus region and simulation modeling suggest fluvial processes

[1] Results from simulation modeling of crater degradation by fluvial and eolian processes are compared with size-frequency and depth of infilling statistics for the heavily cratered Sinus Sabaeus quadrangle of Mars. The fractional degree of infilling of craters greater than 10 km in diameter in this region is bimodal, with a small population of post-Noachian craters with little infilling, whereas most Noachian craters are strongly infilled. This pattern is most consistent with fluvial erosion of craters, because modeling indicates that craters fill rapidly at first, but the rate of infilling diminishes through time as crater wall heights diminish and the area of deposition on the crater floor increases. Simulated rates of crater infilling by eolian processes are more constant, which would be expected to produce craters equally distributed in degree of infilling, which is not observed. The small slope of the size-frequency distribution in the 10–30 km size range is also consistent with the more rapid fluvial erosion of smaller craters. The analysis also suggests that rates of crater production and of crater degradation were in rough balance during the Noachian epoch in the 10–30 km size range.
Laplacian growth as one-dimensional turbulence

Abstract A new model of Laplacian stochastic growth is formulated using conformal mappings. The model describes two growth regimes, stable and turbulent, separated by a sharp phase transition. The first few Fourier components of the mapping define the web, an envelope of the cluster. The web is used to study the transition and the dynamics of large-scale features of the cluster characterized by evolution from macro- to micro-scales. Also, we derive scaling laws for the cluster size.
ERCW PRAMs and optical communication

This paper presents algorithms and lower bounds for several fundamental problems on the Exclusive Read, Concurrent Write Parallel Random Access Machine (ERCW PRAM) and some results for unbounded fan-in, bounded fan-out (or ''BFO'') circuits. Our results for these two models are of importance because of the close relatinship of the ERCW model to the OCPC model, a model of parallel computing based on dynamically reconfigurable optical networks, and of BFO circuits to the OCPC model with limited dynamic reconfiguration ability.
Superconducting to normal state phase boundary in arrays of ultrasmall Josephson junctions

Abstract We study the competition between Josephson and charging energies in two-dimensional arrays of ultrasmall Josephson junctions, when the mutual capacitance is dominant over the self-capacitance. Our calculations involve a combination of an analytic WKB renormalization group approach plus nonperturbative Quantum Monte Carlo simulations. We consider the zero frustration case in detail and we are able to make a successful comparison between our results and those obtained experimentally.
Interaction of a contact resonance of microspheres with surface acoustic waves.

We study the interaction of surface acoustic waves (SAWs) with a contact-based vibrational resonance of $1\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$ silica microspheres forming a two-dimensional granular crystal adhered to a substrate. The laser-induced transient grating technique is used to excite SAWs and measure their dispersion. The measured dispersion curves exhibit ``avoided crossing'' behavior due to the hybridization of the SAWs with the microsphere resonance. We compare the measured dispersion curves with those predicted by our analytical model and find excellent agreement. The approach presented can be used to study the contact mechanics and adhesion of micro- and nanoparticles as well as the dynamics of microscale granular crystals.
Lattice Quantum Gravity: Review and Recent Developments

We review the status of different approaches to lattice quantum gravity indicating the successes and problems of each. Recent developments within the dynamical triangulation formulation are then described.
Comparison of Tensile Fatigue Resistance and Constant Life Diagrams for Several Potential Wind Turbine Blade Laminates

New fatigue test results are presented for four multidirectional laminates of current and potential interest for wind turbine blades, representing three types of fibers: E-glass, WindStrand™ glass, and carbon, all with epoxy resins. A broad range of loading conditions is included for two of the laminates, with the results represented as mean and 95/95 confidence level constant life diagrams. The constant life diagrams are then used to predict the performance under spectrum fatigue loading relative to an earlier material. Comparisons of the materials show significant improvements under tensile fatigue loading for carbon, WindStrand, and one of the E-glass fabrics relative to many E-glass laminates in the 0.5-0.6 fiber volume fraction range. The carbon fiber dominated laminate shows superior fatigue and static strengths, as well as stiffness, for all loading conditions.
Standard model explanations for the NuTeV electroweak measurements

The NuTeV Collaboration has measured the electroweak parameters sin{sup 2} {theta}{sub W} and {rho} in neutrino-nucleon deep-inelastic scattering using a sign-selected beam. The nearly pure {nu} or {bar {nu}} beams that result provide many of the cancellations of systematics associated with the Paschos-Wolfenstein relation. The extracted result for sin{sup 2} {theta}{sub W}(on-shell) = 1 - M{sub W}{sup 2}/M{sub Z}{sup 2} is three standard deviations from prediction. We discuss Standard Model explanations for the puzzle.
Numerical Simulation of Dual-Media Thermal Energy Storage Systems

A finite-difference, predictor-corrector, numerical technique originated by MacCormack is used to solve for fluid and solid temperature distributions in one dimensional flow through a finite length packed bed. The method allows for temperature dependent properties, time varying inlet conditions and nonuniform initial conditions. Computed results agree with the classical Schumann model to within 1% in simulations which exhibit thermal gradients as large as 310/sup 0/C/m. Additional examples illustrate the attractive characteristics of the method, namely its accuracy, flexibility, ease of implementation, and computational efficiency.
The Saudi Healthcare System: A View from the Minaret

This review article provides information about the origins, history, evolution and current status of the Saudi healthcare system, which is currently being transformed from a publicly financed and managed welfare system to a market-oriented, employment-based, insurance-driven system. Since its inception in the 1920s, the system has provided free healthcare to all Saudi nationals at publicly owned facilities run by government-employed administrators and healthcare providers. For millions of foreign workers in the country, healthcare at privately owned for-profit facilities has been paid for either by the employer or by the individual. At the completion of the three-stage transition, everyone in the country, whether employed in the public or private sector, is expected to have insurance coverage provided by the employer. All Ministry of Health-owned hospitals will be divested to the private sector, whereas primary health centres are likely to be retained by the government. Many of the operational details of the transition are unclear at this stage and will be worked out in the coming years. This paper provides a context for these changes and highlights some of the existing issues and weaknesses. The article also points to some of the future challenges and cautions against pitfalls involved in the complete transformation of the system.
Combining Undersampled Dithered Images

Undersampled images, such as those produced by the HST WFPC-2, misrepresent fine-scale structure intrinsic to the astronomical sources being imaged. Analyzing such images is difficult on scales close to their resolution limits and may produce erroneous results. A set of "dithered" images of an astronomical source generally contains more information about its structure than any single undersampled image, however, and may permit reconstruction of a "superimage" with Nyquist sampling. I present a tutorial on a method of image reconstruction that builds a Nyquist superimage from a complex linear combination of the Fourier transforms of a set of undersampled dithered images. This method works by algebraically eliminating the high-order satellites in the periodic transforms of the aliased images. The reconstructed image is an exact representation of the data set with no loss of resolution at the Nyquist scale. The algorithm is directly derived from the theoretical properties of aliased images and involves no arbitrary parameters, requiring only that the dithers are purely translational and constant in pixel space over the domain of the object of interest. I show examples of its application to WFC and PC images. I argue for its use when the best recovery of point sources or morphological information at the HST diffraction limit is of interest.
HERO: Hierarchical Energy Optimization for Data Center Networks

The rapid escalating power consumption has become critically important to modern data centers. Existing works on reducing the power consumption of network elements formulate the power optimization problem for a general network topology and require a centralized controller. As the scale of data centers increases, the complexity of solving this optimization problem increases rapidly. Inspired from the hierarchical data center network (DCN) topologies and data center traffic patterns, we design a two-level, pod-level, and core-level power optimization model, namely, Hierarchical EneRgy Optimization (HERO), to reduce the power consumption of network elements by switching off network switches and links while still guaranteeing full connectivity and maximizing link utilization. Given a physical DCN topology and a traffic matrix, we illustrate that two-level power optimizations in HERO fall in the class of capacitated multicommodity minimum cost flow (CMCF) problem, which is NP-hard. Therefore, we design several heuristic algorithms based on different switch elimination criteria to solve the proposed HERO optimization problem. The power-saving performance of the proposed HERO model is evaluated by several experiments with different traffic patterns. Our simulations demonstrate that HERO can reduce power consumptions of network elements effectively with reduced complexity.
Toward a versatile allylation reagent: practical, enantioselective allylation of acylhydrazones using strained silacycles.

A highly practical method for the enantioselective allylation of acylhydrazones has been developed. The previously reported strained silacycle reagent 1 reacts with a wide variety of acylhydrazones to give the hydrazide products with good enantioselectivity (83−89% ee, typically). It has been demonstrated that the products may be isolated without chromatography by recrystallization in ≥98% ee.
Suppression of Spiral Growth in Molecular Beam Epitaxy of GaN on Vicinal 6H‐SiC(0001)

The surface morphology of GaN thin films grown by molecular beam epitaxy on nominal flat and vicinal 6H-SiC(0001) substrates was characterized by in situ scanning tunneling microscopy. On flat substrates, screw dislocations emerge at the surface, creating straight steps along the direction for 50 nm film thickness. As growth proceeds, these steps wind around the dislocations and form spirals for film thickness of about 100 nm. In contrast, the spiral growth is completely suppressed on vicinal substrates, and step-flow growth was observed. Based on the Burton, Cabrera, and Frank theory, a model is proposed to explain the suppression of the spiral growth on vicinal substrates.
A Decision Support Tool for Using an ICD-10 Anatomographer to Address Admission Coding Inaccuracies: A Commentary

Abstract In the chaotic environment of an emergency department trauma unit, accuracy and timeliness in decision making are required to save a patient’s life. In a large urban city, where gun violence is high, emergency department physicians must have a wide array of tools in order to effectively and efficiently treat victims of gun violence and ensure that their diagnoses are properly coded. A disparity currently exists between the accuracy of ICD-9 admission coding and discharge coding with some error rates as much as seventy percent. [1,2,3,4] The elevated error rate is poised to increase even more, as the US transitions from ICD-9 to ICD-10 coding standard. The proposed decision support tool, the ICD-10 anatomographer, will have many advantages to medical professionals working in high-intensity settings. Emergency department physicians in busy trauma care units in large urban hospitals will be able to utilize this technology to find the accurate ICD-10 code in an efficient manner, thereby improving quality of care and saving lives. Keywords: decision support, ICD-9 to ICD-10 transition, anatomography
Probing the membrane potential of living cells by dielectric spectroscopy.

In this paper we demonstrate a quantitative way to measure the membrane potential of live cells by dielectric spectroscopy. We also show that the values of the membrane potential obtained using our technique are in good agreement with those obtained using traditional methods—voltage-sensitive dyes. The membrane potential is determined by fitting the experimental dielectric dispersion curves with the dispersion curves obtained from a theoretical model. Variations in the membrane potential were induced by modifying the concentration of potassium chloride in the solution of the cell suspension in the presence of valinomycin. For exemplification of the method, E. coli was chosen for our experiments.
Spin photovoltaic effect in quantum wires with Rashba interaction

We propose a mechanism for spin-polarized photocurrent generation in quantum wires. The effect is due to the combined effect of Rashba spin-orbit interaction, external magnetic field, and microwave radiation. The time-independent interactions in the wire give rise to a spectrum asymmetry in k space. The microwave radiation induces transitions between spin-splitted subbands, and, due to the peculiar energy dispersion relation, charge and spin currents are generated at zero-bias voltage. We demonstrate that the generation of pure spin currents is possible under an appropriate choice of external control parameters.
Total Synthesis of (±)-Jiadifenin, a Non-peptidyl Neurotrophic Modulator

We report the first total synthesis of jiadifenin (1), the establishment of a modality for its biological evaluation, and the discovery of apparently more potent neurotrophic activity in fully synthetic compound 17, an intermediate en route to 1.
Framing the Right Suspects: Measuring Media Bias

This article examines ideological bias in six large daily newspapers and The Associated Press. The media examined are three to six times more likely to associate ideological labels (or frames) with organizations (think tanks) with a conservative orientation than think tanks having a liberal orientation. This tends to frame the analyses done by conservative think tanks as less objective than the analysis done by liberal think tanks. Regression results suggest that approximately three-fourths of the explained differential in framing rates is due to media bias. The rest is primarily explained by the differential in the “quality” of think tanks.
Charge expulsion from black brane horizons, and holographic quantum criticality in the plane

Quantum critical behavior in 2+1 dimensions is established via holographic methods in a 5+1-dimensional Einstein gravity theory with gauge potential form fields of rank 1 and 2. These fields are coupled to one another via a tri-linear Chern-Simons term with strength k. The quantum phase transition is physically driven by the expulsion of the electric charge from inside the black brane horizon to the outside, where it gets carried by the gauge fields which acquire charge thanks to the Chern-Simons interaction. At a critical value k = k c , zero temperature, and any finite value of the magnetic field, the IR behavior is governed by a near-horizon Lifshitz geometry. The associated dynamical scaling exponent depends on the magnetic field. For k < k c , the flow towards low temperature is governed by a Reissner-Nordstrom-like black brane whose charge and entropy density are non-vanishing at zero temperature. For k > k c , the IR flow is towards the purely magnetic brane in AdS6. Its near-horizon geometry is AdS4 × R 2, so that the entropy density vanishes quadratically with temperature, and all charge is carried by the gauge fields outside of the horizon.
The problem of political calculation in autocracies

Autocrats depend on their followers to remain in power. They compensate the followers in exchange for their support. Yet, they have few tools to guide them in determining the compensation commensurate with the value of each follower’s support. The failure of political calculation can easily lead to the autocrat’s demise. In semi-authoritarian and democratic regimes, elections provide a solution to the problem of political calculation. In elections, citizens cast votes in exchange for public or private goods. Thus, the number of votes received by candidates and parties can be used as a proxy for the value of their support.
Light cone quantization of the c=2 matrix model

Abstract We study the large N limit of an interacting two-dimensional matrix field theory, whose perturbative expansion generates the sum over planar random graphs embedded in two-dimensions. In the light cone quantization the theory possesses closed string excitations which become free as N→∞. If the longitudinal momenta are discretized, then the calculation of the free string spectrum reduces to finite matrix diagonalization, the size of the matrix growing as the cut-off is removed. Our numerical results suggest that, for a critical coupling, the light cone string spectrum becomes continuous. This would indicate the massless dynamics of the Liouville mode of two-dimensional gravity, which would constitute a third dimension of the string theory.
Structural tailoring and feedback control synthesis - An interdisciplinary approach

Structural tailoring provides an attractive method to optimize the performance of actively controlled space structures. However, the simultaneous optimization of control gains and structural properties often becomes prohibitively expensive for large systems and physical insight is often lost in the resulting control law. This paper presents a method for optimization of the closed loop structural system using only structural tailoring. Optimal Linear Quadratic Regulator (LQR) control theory is used with weighting matrices chosen based on physical considerations. The LQR control law depends only on two scalar gains and the structural properties. Hence, the closed loop-performance can be expressed in terms of the structural parameters. Results are given for a beam and a truss-beam to show the simplicity of the method and the importance of structural tailoring to increase dynamic performance and to reduce the control effort.
(1 + eps)-Approximate Sparse Recovery

The problem central to sparse recovery and compressive sensing is that of \emph{stable sparse recovery}: we want a distribution $\math cal{A}$ of matrices $A \in \R^{m \times n}$ such that, for any $x \in \R^n$ and with probability $1 - \delta &gt, 2/3$ over $A \in \math cal{A}$, there is an algorithm to recover $\hat{x}$ from $Ax$ with\begin{align} \norm{p}{\hat{x} - x} \leq C \min_{k\text{-sparse } x'} \norm{p}{x - x'}\end{align}for some constant $C &gt, 1$ and norm $p$. The measurement complexity of this problem is well understood for constant $C &gt, 1$. However, in a variety of applications it is important to obtain $C = 1+\eps$ for a small $\eps &gt, 0$, and this complexity is not well understood. We resolve the dependence on $\eps$ in the number of measurements required of a $k$-sparse recovery algorithm, up to polylogarithmic factors for the central cases of $p=1$ and $p=2$. Namely, we give new algorithms and lower bounds that show the number of measurements required is $k/\eps^{p/2} \textrm{polylog}(n)$. For $p=2$, our bound of $\frac{1}{\eps}k\log (n/k)$ is tight up to \emph{constant} factors. We also give matching bounds when the output is required to be $k$-sparse, in which case we achieve $k/\eps^p \textrm{polylog}(n)$. This shows the distinction between the complexity of sparse and non-sparse outputs is fundamental.
Electrochemistry of six- and seven-coordinate MoO4+ complexes. A dramatic influence of coordination number on electron transfer reversibility and metal-centered reduction potential

Etude electrochimique par voltammetrie cyclique de complexes du molybdene(VI) avec des derives du catechol, dithiocarbamique et le naphtalenediol-2,3.Influence de la nature du coordinat sur les proprietes redox.
An interface for novice and infrequent database management system users

Special interfaces are needed for novice and infrequent users of database management systems. Such interfaces must remind users of the structure and names of database objects as they guide users in formulating syntactically valid database commands. A prototype system developed at the Honeywell Corporate Technology Center provides such an interface by integrating schema displays depicting the contents and structure of the database and syntax diagrams representing the valid syntactic options of a database query language. By traversing these graphs, novice and infrequent database management system users can easily formulate syntactically valid database management system commands while learning the formal syntax of the database management system command language.
Twisted tales; or story, study, and symphony

Nothing strikes us as unusual here even though the order of telling completely reverses the order of occurrence. Indeed, to have withheld the result of the race to the end would have been inconsiderate under the circumstances. In other reports the telling may jump back and forth; for example: Excalibur, though he broke last from the gate, won by a nose after having dropped back to fourth, coming into the stretch, from the lead he had taken by the far turn.
Synthesis of N‐Benzylated Anilines from the Reaction of Anilines and Benzyl Chloroformate

Abstract Reactions of benzyl chloroformate with a series of substituted anilines produced N‐carbobenzyloxy “CBZ” products along with the unexpected N‐benzylated “Bn” compounds. Reaction of aniline, 1a, gave the CBZ, or 2a, and Bn, or 3a, products in 29% and 14% yield, respectively. For 2‐nitro‐, 2‐bromo‐, and 2‐bromo‐5‐nitroanilines, the N‐benzylated compounds were produced exclusively. However, 2‐methoxy‐, 4‐bromo, 4‐iodo, and 4‐ethylanilines gave mainly CBZ products. Other compounds reported in this study gave mixtures of the two products. For 4‐chloro‐3‐nitroaniline, in addition to the Bn and CBZ products (53% and 14% yield, respectively), a N,N‐dibenzylated product was isolated in 27% yield. Collectively, the results indicated that electron‐withdrawing groups, particularly at the ortho position, directed the formation of Bn compounds, whilst electron‐donating groups, especially at the ortho and para positions, favored the synthesis of CBZ products.
A Thermal Conductivity Model for Micro-Nanoscale Diamond Thin Films Using Dispersion Curve Data

Thermal conductivity is investigated for a cubic C (diamond). Boundary scattering, Umklapp processes, normal processes, and the presence of impurities are the mechanisms considered for heat flow resistance. Three symmetry directions [001], [110], [111], and three polarizations for each direction in the first Brillouin zone are considered for the material. The main purpose of this study is to analyze the effect of the curvature of phonon dispersion curves on the thermal conductivity, and develop an accurate model. The model incorporates the effects of impurity and impurity concentration, film thickness, and crystal orientation on thermal conductivity. The model is validated by comparing results with experimental data for diamond in the [111] direction. The model is then used for the other symmetry directions using the appropriate dispersion curves. The results show that the curvature of the dispersion curves dramatically affects the thermal conductivity. A sensitivity analysis is conducted to study the effect of boundary scattering as the film decreases in thickness and the effect of impurities.
Quasiparticle interference on the surface of the topological insulator Bi 2 Te 3

The quasiparticle interference of the spectroscopic imaging scanning tunneling microscopy has been investigated for the surface states of the large gap topological insulator ${\text{Bi}}_{2}{\text{Te}}_{3}$ through the $T$-matrix formalism. Both the scalar-potential scattering and the spin-orbit scattering on the warped hexagonal isoenergy contour are considered. While backscatterings are forbidden by time-reversal symmetry, other scatterings are allowed and exhibit strong dependence on the spin configurations of the eigenfunctions at $\stackrel{P\vec}{k}$ points over the isoenergy contour. The characteristic scattering wave vectors found in our analysis agree well with recent experiment results.
Candidates, Character, and Corruption

We study the characteristics of self-selected candidates in corrupt political systems. Potential candidates dier along two dimensions of unobservable character: public spirit (altruism toward others) and honesty (the disutility suered when selling out to special interests after securing oce). Both aspects combine to determine an individual’s quality as governor. We characterize properties of equilibrium candidate pools for arbitrary costs of running for oce, including the case where those costs become vanishingly small. We explore how policy instruments such as the governor’s compensation and anti-corruption enforcement aect the expected quality of governance through candidate self-selection. We also show that self-selection can have surprising implications for the eect of information disclosures concerning candidates’ backgrounds.
Dichloroborane-Dimethyl Sulfide, A Highly Selective Reducing Agent for Reduction of Organyl Azides to Amines.

Abstract Dichloroborane-dimethyl sulfide reduces a variety of organyl azides, such as primary, secondary, tertiary, and aromatic to the corresponding amines in excellent yields. Cycloalkyl and benzylic azides are also readily reduced by this reagent. The reduction of azide with BHCl 2 SMe 2 is highly selective and many functional groups, such as halogen, ester, nitrile, aliphatic and aromatic nitro, survive in this process.
Non-diffusive, non-local transport in fluids and plasmas

Abstract. A review of non-diffusive transport in fluids and plasmas is presented. In the fluid context, non-diffusive chaotic transport by Rossby waves in zonal flows is studied following a Lagrangian approach. In the plasma physics context the problem of interest is test particle transport in pressure-gradient-driven plasma turbulence. In both systems the probability density function (PDF) of particle displacements is strongly non-Gaussian and the statistical moments exhibit super-diffusive anomalous scaling. Fractional diffusion models are proposed and tested in the quantitative description of the non-diffusive Lagrangian statistics of the fluid and plasma problems. Also, fractional diffusion operators are used to construct non-local transport models exhibiting up-hill transport, multivalued flux-gradient relations, fast pulse propagation phenomena, and "tunneling" of perturbations across transport barriers.
What Does It Take to Stabilize Gravitational Clustering

An analytical understanding of the strongly nonlinear regime of gravitational collapse has been difficult to achieve. The only insight has been the stable clustering hypothesis, which assumes that the number of neighbors for objects averaged over small length scales is constant in time. Our recently proposed analytic halo model for N-point correlation functions now provides a tool for calculating gravitational clustering properties in the strongly nonlinear regime. This model also provides a new physical framework for an independent evaluation of the validity of the stable clustering hypothesis. We derive the asymptotic nonlinear behavior of the N-point correlation functions and pairwise peculiar velocities in terms of dark matter halo properties. We show that these statistics exhibit stable clustering only when the halo mass function and halo density profile obey specific relations. The long-cherished stable clustering hypothesis therefore is not necessarily realized in practice.
A cell-centered adaptive projection method for the incompressible Navier-Stokes equations in three dimensions

We present a method for computing incompressible viscous flows in three dimensions using block-structured local refinement in both space and time. This method uses a projection formulation based on a cell-centered approximate projection, combined with the systematic use of multilevel elliptic solvers to compute increments in the solution generated at boundaries between refinement levels due to refinement in time. We use an L0-stable second-order semi-implicit scheme to evaluate the viscous terms. Results are presented to demonstrate the accuracy and effectiveness of this approach.
Modelling with implicit surfaces that interpolate

We introduce new techniques for modelling with interpolating implicit surfaces. This form of implicit surface was first used for problems of surface reconstruction and shape transformation, but the emphasis of our work is on model creation. These implicit surfaces are described by specifying locations in 3D through which the surface should pass, and also identifying locations that are interior or exterior to the surface. A 3D implicit function is created from these constraints using a variational scattered data interpolation approach, and the iso-surface of this function describes a surface. Like other implicit surface descriptions, these surfaces can be used for CSG and interference detection, may be interactively manipulated, are readily approximated by polygonal tilings, and are easy to ray trace. A key strength for model creation is that interpolating implicit surfaces allow the direct specification of both the location of points on the surface and the surface normals. These are two important manipulation techniques that are difficult to achieve using other implicit surface representations such as sums of spherical or ellipsoidal Gaussian functions ("blobbies"). We show that these properties make this form of implicit surface particularly attractive for interactive sculpting using the particle sampling technique introduced by Witkin and Heckbert. Our formulation also yields a simple method for converting a polygonal model to a smooth implicit model, as well as a new way to form blends between objects.
Effects of land-use change on channel morphology in northeastern Puerto Rico

Between 1830 and 1950 much of northeastern Puerto Rico was cleared for agriculture. Runoff increased by 50% and sediment supply to the river channels increased by more than an order of magnitude. Much of the land clearance extended to steep valley slopes, resulting in widespread gullying and landslides and a large load of coarse sediments delivered to the stream channels. A shift from agriculture to industrial and residential land uses over the past 50 yr has maintained the elevated runoff while sediment supply has decreased, allowing the rivers to begin removing coarse sediment stored within their channels. The size, abundance, and stratigraphic elevation of in-channel gravel bar deposits increases, channel depth decreases, and the frequency of overbank flooding increases downstream along these channels. This is presumed to be a transient state and continued transport will lead to degradation of the bed in downstream sections as the channel adjusts to the modern supply of water and sediment. A downstream decrease in channel size is contrary to the expected geometry of self-adjusted channels, but is consistent with the presence of partially evacuated sediment remaining from the earlier agricultural period. Reverse (downstream decreasing) channel morphology is not often cited in the literature, although consistent observations are available from areas with similar land-use history. Identification of reverse channel morphology along individual watercourses may be obscured in multiwatershed compilations in which other factors produce a consistent, but scattered downstream trend. Identification of reverse channel morphology along individual streams in areas with similar land-use history would be useful for identifying channel disequilibrium and anticipating future channel adjustments.
Isolated lymphadenopathy on chest radiographs of HIV-infected patients.

Abstract Aim: To determine the aetiology of isolated intrathoracic lymphadenopathy on chest radiographs of HIV-infected patients. Patients and Methods: Over a 40 month span in 1990–1993, 18 HIV-infected patients (13 men, 5 women) from our New York City adult HIV outpatient clinic development isolated intrathoracic lymphadenopathy (defined as intrathoracic nodal enlargement without other persistent abnormalities on chest radiographs). Serial chest radiographs ( n = 18), CT scans when available ( n = 7), and clinical charts ( n = 18) were reviewed retrospectively. Results: Median patient age was 34 (range 25–49) years. The diagnoses associated with adenopathy were Mycobacterium tuberculosis (Mtb) in eight (44%), Mycobacterium avium intracellulare complex (MAC) in four (22%), and Mtb and MAC co-infection in three (17%). Cryptococcal infection, thymic hyperplasia, and spontaneous resolution without diagnosis or treatment occurred in one patient each. In 16 (89%) of the 18 patients, lymphadenopathy was present in more than one nodal station. Enlarged nodes were found in the following sites: paratracheal/tracheobronchial ( n = 14), aortopulmonary window ( n = 9), hilar ( n = 7), anterior mediastinum ( n = 3), subcarinal ( n = 2), and left paraesophageal ( n = 2). Conclusion: Mycobacterial infection was the aetiology of isolated intrathoracic lymphadenopathy in 15 of 18 (83%) HIV-infected patients. When an inner city HIV-infected patient presents with isolated intrathoracic lymphadenopathy, we recommend an aggressive work-up for mycobacterial disease.
Modulation of the earthquake cycle at the southern San Andreas fault by lake loading

[1] Changes in the level of ancient Lake Cahuilla over the last 1500 years in the Salton Trough alter the state of stress by bending the lithosphere in response to the applied lake load and by varying the pore pressure magnitude within the crust. The recurrence interval of the lake is similar to the recurrence interval of rupture on the southern San Andreas and San Jacinto faults, both of which are partially covered by the lake at its highstand. Furthermore, four of the last five ruptures on the southern San Andreas fault have occurred near a time of substantial lake level change. We investigate the effect of Coulomb stress perturbations on local faults due to changing level of Lake Cahuilla to determine a possible role for the lake in affecting the timing of fault rupture. Coulomb stress is calculated with a three-dimensional model of an elastic plate overlying a viscoelastic half-space. Plate thickness and half-space relaxation time are adjusted to match observed vertical deformation since the last lake highstand. The lake cycle causes positive and negative Coulomb stress perturbations of 0.2–0.6 MPa on the southern San Andreas within the lake and 0.1–0.2 MPa on the southern San Andreas outside the lake. These Coulomb stress perturbations are comparable to stress magnitudes known to have triggered events at other faults along the North America-Pacific plate boundary.
Inhomogeneous Helium Reionization and the Equation of State of the Intergalactic Medium

The temperature of the intergalactic medium (IGM) is set by the competition between photoheating and adiabatic cooling, which are usually assumed to define a tight equation of state in which the temperature increases monotonically with density. We use a semianalytic model, accurate at low to moderate IGM densities (5 times the mean), to show that inhomogeneous reionization can substantially modify these expectations. Because reionization is driven by biased sources, dense pockets of the IGM are likely to be ionized first. As a result, voids initially remain cool while dense regions are heated substantially. However, near the end of reionization, dense regions have already cooled from their initially large temperature while voids have only just been heated. Thus, near the end of helium reionization the equation of state can invert itself, with the hottest gas inside voids. The degree to which this happens depends on the magnitude of the density bias during reionization: if rare, bright sources dominate reionization, so that each ionized region contains a typical volume of the IGM, the equation of state will remain monotonic. We also show that the distribution of temperatures at a fixed density has significant scatter and evolves rapidly throughout and even after reionization. Finally, we show that the observed temperature jump at z ~ 3.2 is consistent with the behavior at the end of helium reionization, although it requires a somewhat larger temperature increase than expected.
The Network Structure of Exploration and Exploitation

Whether as team members brainstorming or cultures experimenting with new technologies, problem solvers communicate and share ideas. This paper examines how the structure of communication networks among actors can affect system-level performance. We present an agent-based computer simulation model of information sharing in which the less successful emulate the more successful. Results suggest that when agents are dealing with a complex problem, the more efficient the network at disseminating information, the better the short-run but the lower the long-run performance of the system. The dynamic underlying this result is that an inefficient network maintains diversity in the system and is thus better for exploration than an efficient network, supporting a more thorough search for solutions in the long run. For intermediate time frames, there is an inverted-U relationship between connectedness and performance, in which both poorly and well-connected systems perform badly, and moderately connected systems perf...