cssi/SciSciGPT-SciSciNet huggingface dataset:
A Hydrogen Atmosphere Spectral Model Applied to the Neutron Star X7 in the Globular Cluster 47 Tucanae

Current X-ray missions are providing high-quality X-ray spectra from neutron stars (NSs) in quiescent low-mass X-ray binaries (qLMXBs). This has motivated us to calculate new hydrogen atmosphere models, including opacity due to free-free absorption and Thomson scattering, thermal electron conduction, and self-irradiation by photons from the compact object. We have constructed a self-consistent grid of neutron star models covering a wide range of surface gravities, as well as effective temperatures, which we make available to the scientific community. We present multiepoch Chandra X-ray observations of the qLMXB X7 in the globular cluster 47 Tuc, which is remarkably nonvariable on timescales from minutes to years. Its high-quality X-ray spectrum is adequately fitted by our hydrogen atmosphere model without any hard power-law component or narrow spectral features. If a mass of 1.4 M☉ is assumed, our spectral fits require that its radius be in the range Rns = 14.5 km (90% confidence), which is larger than that expected from currently preferred models of NS interiors. If its radius is assumed to be 10 km, then a mass of Mns = 2.20 M☉ is required. Using models with the appropriate surface gravity for each value of the mass and radius becomes important for interpretation of the highest quality data.
The brain's dark energy.

The article discusses how the regions of the human brain that are activated when an individual's mind wanders may offer scientific insight into neurological disorders and consciousness. Topics include the brain's default mode network (DMN), which is an unrecognized brain system that becomes activated when an individual's brain is in various states of rest, such as daydreaming. Also discussed is how miswiring in the brain's DMN regions may lead to neurological diseases, such as Alzheimer's. INSETS: BRAINS AT REST;A CLUE TO THE NEW VIEW;THE DEFAULT MODE NETWORK;DISEASE AND THE NETWORK
Preparation of nitriles from carboxylic acids: A new, synthetically useful example of the Smiles rearrangement

Abstract Reaction of 2,4-dinitrobenzenesulfonamide with acyl chlorides in the presence of excess triethylamine produces the corresponding nitrile in good to fair yields. Mechanistic studies indicate that the reaction proceeds via a Smiles rearrangement of the initially formed N-(2,4-dinitrobenzenesulfonyl)amide to form the nitrile, 2,4-dinitrophenol and sulfur dioxide.
MEASUREMENT OF THE CASIMIR INTERACTION BETWEEN A Au SPHERE AND Au GRATINGS

The measurements between a Au coated sphere and Au gratings with different structural parameters are presented. While the main effect of the grating is to reduce the interaction observed between the same sphere and a Au plane at the same distance, it is observed that the reduction is non-trivial. While at small separations the interaction is greater than what is expected from purely geometrical effects, at large separations the effect not only becomes smaller but it also presents a faster decay than the corresponding geometrical contribution.
Flutter Spectral Measurements Using Stationary Pressure Transducers

The paper deals with an analysis procedure, based on engine-order sampling, which eliminates effectively the engine harmonics from the overall flutter spectra obtained with a case-mounted static pressure transducer. Qualitative spectral analyses of pressure data, performed on the basis of blade order sampling, are examined. The interference of blade motion with the pressure signal in the steep gradient portion of the blade passage is demonstrated, using optimal displacement spectra. Two methods which remove the contribution of blade motion from the blade-pressure-difference spectra are described.
‘Black atlantics’, ‘white Indians’ and ‘Jews’: Locations, locutions, and syncretic identities in the fiction of Achmat Dangor and others

Narratives of migration, diaspora, settlement and naming on and around the 'Cape of Storms' burst the bounds of apartheid racial classifications or, indeed, of anti-apartheid categories.
Perfect quantum transport in arbitrary spin networks

Spin chains have been proposed as wires to transport information between distributed registers in a quantum information processor. Unfortunately, the challenges in manufacturing linear chains with engineered couplings has hindered experimental implementations. Here we present strategies to achieve perfect quantum information transport in arbitrary spin networks. Our proposal is based on the weak coupling limit for pure state transport, where information is transferred between two end spins that are only weakly coupled to the rest of the network. This regime allows ignoring the complex, internal dynamics of the bulk network and relying on virtual transitions or on the coupling to a single bulk eigenmode. We further introduce control methods capable of tuning the transport process and achieve perfect fidelity with limited resources, involving only manipulation of the end qubits. These strategies could be thus applied not only to engineered systems with relaxed fabrication precision, but also to naturally occurring networks; specifically, we discuss the practical implementation of quantum state transfer between two separated nitrogen vacancy (NV) centers through a network of nitrogen substitutional impurities.
A short synthesis of (±)-tortuosamine

A four-step synthesis of (±)-tortuosamine (1) is described. The key ring closure was an intramolecular SRN1 reaction between a ketone enolate and a 2-halopyridine.
Statistical entropy of three-dimensional Kerr–de Sitter space

Abstract I consider the (2+1)-dimensional Kerr–de Sitter space and its statistical entropy computation. It is shown that this space has only one (cosmological) event horizon, and there is a phase transition between the stable horizon and the evaporating horizon at a point M 2 = 1 3 J 2 /l 2 together with a lower bound of the horizon temperature. Then I compute the statistical entropy of the space by using a recently developed formulation of the Chern–Simons theory with boundaries, and extended Cardy's formula. This is in agreement with the thermodynamics formula.
Simultaneous autoradiographic and immunohistochemical localization of estrogen and gonadotropin in the rat pituitary

A combined autoradiographic and immunohistochemical technique is introduced which is suitable to simultaneously localize hypophyseal sites of nuclear (3-H)-estradiol uptake and anti-hCG-characterized "gonadotropes". Most, but not all, "gonadotropes" show significant nuclear concentration of radioactivity. A large percentage of non-"gonadotropes" also show nuclear uptake of label.
Alkylation of aromatic amines and related compounds using a copper(II)-aluminum(III) couple

Abstract Copper(II)-mediated alkylation of amines and related compounds (e.g. hydrazines, hydrazones, hydroxylamines) using an alkyl aluminum reagent is described. The reaction proceeds selectively and in good yield, utililizing a metal-metal exchange as the key step.
Remnants of semiclassical bistability in the few-photon regime of cavity QED.

Broadband homodyne detection of the light transmitted by a Fabry-Perot cavity containing a strongly-coupled 133Cs atom is used to probe the dynamic optical response in a regime where semiclassical theory predicts bistability but strong quantum corrections should apply. While quantum fluctuations destabilize true equilibrium bistability, our observations confirm the existence of metastable states with finite lifetimes and a hysteretic response is apparent when the optical drive is modulated on comparable timescales. Our experiment elucidates remnant semiclassical behavior in the attojoule (∼ 10 photon) regime of single-atom cavity QED, of potential significance for ultra-low power photonic signal processing.
Total Synthesis of Vancomycin Aglycon—Part 3: Final Stages

A triazene-based synthetic strategy for the construction of the complex biaryl ethers and a Suzuki coupling reaction were the key steps in the synthesis of precursor 1 of the aglycon of vancomycin, which already contains the complete skeleton of the target compound. The cleavage of the triazene unit from the D ring and the removal of the other protecting groups led to the aglycon of vancomycin. These strategies should be particularly valuable for the synthesis of other naturally occurring glycopeptide antibiotics and offer opportunities for the synthesis of combinatorial libraries of compounds of the vancomycin family for chemical biology studies.
Bioinorganic Chemistry of Group 12 Complexes Supported by Tetradentate Tripodal Ligands Having Internal Hydrogen-Bond Donors

Inspired by the proposed role of secondary hydrogen-bonding interactions in modulating the chemistry of mononuclear zinc centers in metalloenzymes, zinc complexes supported by tetradentate tripodal ligands having one or more internal hydrogen-bond donors have been prepared, characterized, and investigated for biologically relevant reactivity. Complexes of this class have been examined in terms of water activation and CO2 reactivity, alcohol/alkoxide coordination, and amide methanolysis and phosphate ester hydrolysis reactivity. The results of these studies indicate that the presence of internal hydrogen-bond donors will lower the pKa of a zinc-bound water molecule, stabilize zinc alkoxide species with respect to hydrolysis, and enhance the phosphate ester cleavage reactivity of mononuclear zinc complexes. In addition, use of tripodal ligands having a single internal hydrogen-bond donor has enabled the isolation of a novel cadmium hydroxide complex and examination of its CO2 chemistry, as well as the identification of a novel amide cleavage reaction which proceeds by initial formation of a deprotonated amide intermediate. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
A Symbol-Based Algorithm for Decoding Bar Codes

We investigate the problem of decoding a bar code from a signal measured with a hand-held laser-based scanner. Rather than formulating the inverse problem as one of binary image reconstruction, we instead incorporate the symbology of the bar code into the reconstruction algorithm directly, and search for a sparse representation of the Universal Product Code bar code with respect to this known dictionary. Our approach significantly reduces the degrees of freedom in the problem, allowing for accurate reconstruction that is robust to noise and unknown parameters in the scanning device. We propose a greedy reconstruction algorithm and provide robust reconstruction guarantees. Numerical examples illustrate the insensitivity of our symbology-based reconstruction to both imprecise model parameters and noise on the scanned measurements.
Supergravity gauge theories strike back: There is no crisis for SUSY but a new collider may be required for discovery

More than 30 years ago, Arnowitt-Chamseddine-Nath (ACN) and others established the compelling framework of supergravity gauge theories (SUGRA) as a picture for the next step in beyond the Standard Model physics. We review the current SUGRA scenario in light of recent data from LHC8 collider searches and the Higgs boson discovery. While many SUSY and non-SUSY scenarios are highly disfavored or even excluded by LHC, the essential SUGRA scenario remains intact and as compelling as ever. For naturalness, some non-universality between matter and Higgs sector soft terms is required along with substantial trilinear soft terms. SUSY models with radiatively-driven naturalness (RNS) are found with high scale ne-tuning at a modest 10%. In this case, natural SUSY might be discovered at LHC13 but could also easily elude sparticle search endeavors. A linear e + e collider with p s > 2m(higgsino) is needed to provide the denitive search for the required light higgsino states which are the hallmark of natural SUSY. In the most conservative scenario, we advocate inclusion of a Peccei-Quinn sector so that dark matter is composed of a WIMP/axion admixture i.e. two dark matter particles.
Molecular dynamics simulation on a network of workstations using a machine-independent parallel programming language

Abstract Molecular dynamics simulations investigate local and global motion in molecules. Several parallel computing approaches have been taken to attack the most computationally expensive phase of molecular simulations, the evaluation of long range interactions. This paper reviews these approaches and develops a straightforward but effective algorithm using the machine-independent parallel programming language. Linda. The algorithm was run both on a shared memory parallel computer and on a network of high performance Unix workstations. Performance benchmarks were performed on both systems using two proteins. This algorithm offers a portable cost-effective alternative for molecular dynamics simulations. In view of the increasing numbers of networked workstations, this approach could help make molecular dynamics simulations more easily accessible to the research community.
Water-Soluble Palladacycles as Precursors to Highly Recyclable Catalysts for the Suzuki Coupling of Aryl Bromides in Aqueous Solvents

A family of water-soluble palladacycles was prepared from benzylamine or benzaldehyde imine ligands bearing hydrophilic functional groups. The palladacycles derived from N,N-dimethyl-p-hydroxybenzylamine (7) and sodium 4-(N-benzylideneamino)benzenesulfonate (10) gave active catalysts for the Suzuki coupling of aryl bromides and activated aryl chlorides in combination with (2-di-tert-butylphosphinoethyl)trimethylammonium chloride (t-Bu-Amphos). The catalyst derived from 10/t-Bu-Amphos could be used for 12 reaction cycles in the Suzuki coupling of 4-bromotoluene at 80 °C before a significant loss of catalyst activity was observed.
Role of metallic promoters in the direct synthesis of methylchlorosilanes

Overall reaction rates and selectivities for dimethyldichlorosilane were determined for the direct reaction of silicon with methyl chloride to produce methylchlorosilanes. Copper was used as the catalyst, and zinc, tin, and aluminum were investigated as promoters. To unambiguously determine effects of the promoters, high-purity reagents were used for contact mass sample preparation. Others have reported that tin significantly increases both reaction rate and selectivity for samples prepared using technical grade silicon. However, promotion of high purity samples with tin alone (i.e., SiCuSn) significantly decreased both the reaction rate and selectivity. These conflicting results are explained in terms of the aluminum impurities present in technical grade silicon. Tin is suggested to promote this reaction synergistically with zinc and aluminum by lowering the melting points and surface tensions of the catalyst/promoter alloys which form on the surface.
Radiative Cooling in MHD Models of the Quiet Sun Convection Zone and Corona

We present a series of numerical simulations of the quiet-Sun plasma threaded by magnetic fields that extend from the upper convection zone into the low corona. We discuss an efficient, simplified approximation to the physics of optically thick radiative transport through the surface layers, and investigate the effects of convective turbulence on the magnetic structure of the Sun’s atmosphere in an initially unipolar (open field) region. We find that the net Poynting flux below the surface is on average directed toward the interior, while in the photosphere and chromosphere the net flow of electromagnetic energy is outward into the solar corona. Overturning convective motions between these layers driven by rapid radiative cooling appears to be the source of energy for the oppositely directed fluxes of electromagnetic energy.
Aerobic and anaerobic microbiology of bacterial tracheitis in children

Study objectives Establish the aerobic and anaerobic microbiology of bacterial tracheitis in children. Method Retrospective review of specimens obtained from 14 children with bacterial tracheitis that were cultured for aerobic and anaerobic bacteria. Results A total 30 bacterial isolates were recovered, 17 aerobic and facultative anaerobic and 13 anaerobic. Aerobic bacteria only were present in six (43%) specimens, anaerobes only in three (21%), and mixed aerobic and anaerobic flora in five (36%). Polymicrobial flora was recovered in 10 of the 14 specimens. The predominant organisms were Staphylococcus aureus (5 isolates), Haemophilus influenzae type b (4), Peptostreptococcus sp. (4), pigmented Prevotella and Porphyromonas (4), Fusobacterium sp. (2), and Moraxella catarrhalis (2). Two organisms that were also isolated from the tracheal aspirates were recovered from the blood of two patients (one each of H. influenzae and Prevotella intermedia). Eleven beta-lactamase-producing organisms were isolated from nine patients. These included all isolates of S. aureus and M. catarrhalis, and two each of H. influenzae and Prevotella sp. Conclusions These data confirm the predominance of S. aureus and H. influenzae in causing bacterial tracheitis in children and suggest a potential role for anaerobic bacteria.
Quantifying the Inefficiency of the US Social Security System

We quantify the inefficiency of the retirement component of the US social security system within a model where agents receive idiosyncratic labor-productivity shocks that are privately observed
The Magnetic Topology of Coronal Mass Ejection Sources

In an attempt to test current initiation models of coronal mass ejections (CMEs), with an emphasis on the magnetic breakout model, we inspect the magnetic topology of the sources of 26 CME events in the context of their chromospheric and coronal response in an interval of approximately 9 hr around the eruption onset. First we perform current-free (potential) extrapolations of photospheric magnetograms to retrieve the key topological ingredients, such as coronal magnetic null points. Then we compare the reconnection signatures observed in the high-cadence and high spatial resolution Transition Region and Coronal Explorer (TRACE) images with the location of the relevant topological features. The comparison reveals that only seven events can be interpreted in terms of the breakout model, which requires a multipolar topology with preeruption reconnection at a coronal null. We find, however, that a larger number of events (12) cannot be interpreted in those terms. No magnetic null is found in six of them. Seven other cases remain difficult to interpret. We also show that there are no systematic differences between the CME speed and flare energies of events under different interpretations.
Behavior of the sodium and hydroxyl nighttime emissions during a stratospheric warming

The behavior of the sodium and hydroxyl nighttime emissions during a stratospheric warming has been studied principally by use of data from the airglow photometers on the OGO-4 satellite. It was found that during the late stages of a major warming, both emissions increase appreciably, with the sodium emission returning to normal levels prior to the decrease in hydroxyl emission. The emission behaviors are attributed to temperature and density variations from 70 to 94 km, and a one-dimensional hydrostatic model for that altitude range is used to calculate the effects on the emissions and on the mesospheric ozone densities.
Martingale Transforms and Their Projection Operators on Manifolds

We prove the boundedness on L p , 1 < p < ∞, of operators on manifolds which arise by taking conditional expectation of transformations of stochastic integrals. These operators include various classical operators such as second order Riesz transforms and operators of Laplace transform-type.
On-chip DNA band detection in microfabricated separation systems

In recent years, there has been tremendous interest in developing a complete, high-volume, DNA analysis system using microfabrication techniques. Key to the success of such systems, is the development of a high-resolution separation and detection system for analyzing DNA reaction products. Over the past decade, many researchers have demonstrated that micromachined fluidic devices are capable of performing many of the required functions of such a device. However, all of these devices rely on expensive external fluorescence imaging systems that may limit the realization of a low cost, miniature DNA analysis chip. We have developed an on-chip fluorescent detection system and used it to detect individual DNA bands migrating in a microfabricated electrophoretic device. Fluorescence-based detection of DNA bands is achieved by incorporating a highly sensitive photodiode beneath the electrophoresis channel along with a thin film optical filter deposited above the diode. A miniaturized detection system, with sensitivity comparable to macroscale detection systems, could accelerate the realization of integrated `lab-on-a-chip' systems.
Experimental evidence that an asteroid impact led to the extinction of many species 65 million years ago

An overview is presented of the theory that an asteroid hit the earth 65 million years ago wiping out large numbers of land and marine species. This theory predicts that the clay layer found at the boundary of the Cretaceous and Tertiary Periods would be substantially different chemically from the clays in the limestone above and below the boundary layer. It also predicts the iridium enhancement seen in this boundary layer would be found worldwide. Both predictions have been found to be true. A third prediction was made but not fulfilled: that the five major extinctions which occurred in the last 570 million years were caused by an asteroid impact. The transport mechanism of the dust created by the impact and four mechanisms for the extinction of species are discussed. Criticisms of the theory are also discussed.
Eccentricity of Supermassive Black Hole Binaries Coalescing from Gas-rich Mergers

Angular momentum loss to circumbinary gas provides a possible mechanism for overcoming the "last parsec" problem and allowing the most massive black hole binaries formed from galactic mergers to coalesce. Here we show that if gas disks also catalyze the merger of the somewhat lower mass binaries detectable with the Laser Interferometer Space Antenna (LISA), then there may be a purely gravitational wave signature of the role of gas in the form of a small but finite eccentricity just prior to merger. Numerical simulations suggest that eccentricity, excited by the interaction between the binary and surrounding gas disk, is only partially damped during the final phase of gravitational radiation-driven inspiral. We estimate a typical eccentricity at 1 week prior to coalescence of e ≈ 0.01. Higher terminal eccentricities, which can approach e = 0.1, are possible if the binary has an extreme mass ratio. The detection of even a small eccentricity prior to merger by LISA provides a possible discriminant between gas-driven inspirals and those effected by stellar processes.
Direct Measurements of Skin Friction in Supersonic Combustion Flow Fields

Abstract : The final report consists of an AIAA and an ASME paper. An experimental investigation was conducted to measure skin friction along the chamber walls of supersonic combustors. A direct force measurement device was used to simultaneously measure an axial and transverse component of the small tangential shear force passing over a non-intrusive floating element. Skin friction coefficients between 0.001-0.005 were measured dependent on the facility and measurement location . Analysis of the measurement uncertainties indicate an accuracy to within + or - 10-15% of the streamwise component.
The effects of campaign contribution sources on the congressional elections of 1996

Abstract The debate over federal campaign-finance reform necessarily includes how different sources of campaign contributions affect the outcomes of political campaigns. Using data from the Congressional races of 1996, I find that PAC contributions had a larger effect on the percentage of votes received and campaign outcomes relative to individual and political party contributions.
Global convergence for ill-posed equations with monotone operators: the dynamical systems method

Consider an operator equation F(u) = 0 in a real Hilbert space. Let us call this equation ill-posed if the operator F'(u) is not boundedly invertible, and well-posed otherwise. If F is monotone C2loc(H) operator, then we construct a Cauchy problem, which has the following properties: (1) it has a global solution for an arbitrary initial data, (2) this solution tends to a limit as time tends to infinity and (3) the limit is the minimum norm solution to the equation F(u) = 0. An example of applications to linear ill-posed operator equation is given.
Valley singularities and baryon number violation

Abstract We consider the valley-method computation of the inclusive cross section of high-energy baryon number violating processes in the Standard Model. We show that any physically correct model of the valley action should present a singularity in the saddle point valley parameters as functions of the energy of the process. This singularity prevents the saddle point configuration from collapsing into the perturbative vacuum.
The deceptive number changing game, in the absence of symmetry

One player, Changer, in a two-person zero-sum game is given a random vector having independent identically distributed coordinates. He changes a limited number of coordinates and shows the resulting vector to Chooser who then chooses one of the coordinate positions. Changer then pays Chooser the number that was originally in that position. It is shown that if Changer is permitted to change at least half of the coordinates in the vector given to him, then he can show Chooser a vector that will not aid her in making a self-serving choice of a coordinate position.
REE diffusion in olivine

Diffusion of rare earth elements has been characterized in synthetic forsterite and natural olivine (Fo90) under dry conditions. Experiments were prepared by enclosing source material [mixtures of rare-earth element (La, Dy, or Yb) aluminate and synthetic forsterite powders in 3:1 proportions] and polished forsterite in platinum capsules. For buffered experiments on natural olivine, samples were placed with the source in AgPd capsules, sealed under vacuum in silica glass ampoules with a solid buffer (NNO, IW, or graphite). In some experiments, ground natural olivine was also incorporated into the source material. Prepared capsules were annealed in 1 atm furnaces for one hour to several weeks at 850 to 1300 °C. REE distributions in olivine were profiled by Rutherford backscattering spectrometry (RBS). The following Arrhenius relation is obtained for Dy diffusion in forsterite: \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \[\mathit{D}_{Dy}\ =\ 8.0\ {\times}\ 10^{{-}10}\ exp({-}289\ {\pm}\ 21\ kJ\ mol^{{-}1}/RT)\ m^{2}/s.\] \end{document} Diffusivities of Yb and La in forsterite and for Dy in natural olivine are similar. Experiments run on natural olivine show little dependence of diffusion on crystallographic orientation. The Arrhenius relation yields diffusivities about three orders of magnitude smaller than those determined for REE diffusion in olivine by Spandler et al. (2007) and suggests that timescales for preservation of REE signatures in olivine-hosted melt inclusions may be relatively long. REE diffusivities in olivine are an order of magnitude faster than those of REE+3 in enstatite (Cherniak and Liang 2007) and in diopside under most conditions (Van Orman et al. 2001). Hence, REE signatures in olivine are more likely to be altered by diffusion than those of clinopyroxene or orthopyroxene.
SPACETIME: PROBING FOR 21ST CENTURY PHYSICS WITH CLOCKS NEAR THE SUN

We will describe a space mission study based on three high-precision atomic clocks, flying to within six solar radii of the Sun, for a test of the possible variation of the fine structure constant, α. The three clocks are based on transitions in three different atomic species. Measurement of the drift in ratios between the frequencies generated by each clock will probe for the variation of α. Since the response of each atomic species to a change in α has a specific signature, this measurement will provide sensitive and unambiguous results. The sensitivity of this experiment to a changing α is comparable to the sensitivity of recent tests based on observational astronomy, exceeding the geophysical bounds on α variations. Thus, the experiment will provide a compelling reaffirmation or refutation of astronomical observations, and represents an important test of the models aimed at bridging physics of the quantum to the cosmos.
HTML to the max: a manifesto for adding SGML intelligence to the World-Wide Web

Abstract HTML demonstrates that SGML markup is useful for networked information. How can it be made even more useful? One way is to extend the tag set from HTML to HTML2, etc. We argue here for a more radical approach: full SGML awareness in WWW. We believe the difficulties are small, the cost affordable, and the advantages overwhelming. SGML is a metalanguage for defining markup languages; HTML is just one instance of this infinite family. At present, documents in other SGML document types must be translated into HTML for display by a Mosaic client—sometimes this imposes unacceptable information loss. WWW browsers could handle other SGML document types without translation by launching a general-purpose SGML browser to view them, as they now launch graphics viewers; a better solution overall would be to build SGML display into the WWW browsers themselves. Either way, display of an SGML document would be controlled by a style sheet using a small number of display primitives (“bold”, “line break”, etc.) to specify the rendition of each element type. For “well-known” document type definitions (DTDs) like HTML, style sheets could be distributed with the browser, or built in. For other DTDs, the browser would fetch a style sheet from the server. Using style sheets, browser software can also make it easy to customize document display. DTDs and style sheets can be designed to accommodate extensions, ensuring that authors can make small extensions to the tag set with no change whatsoever in the target browsers and virtually no performance penalty.
Intramolecular Pd-catalyzed aryl-enone conjugate additions. Control of reductive vs non-reductive cyclization

Pd-catalyzed aryl-enone cyclization of 1 leads to Heck-type non-reductive cyclization product 3 and reductive cyclization product 4. Conditions have been developed to selectively form either 3 or 4 (or more highly functionalized 10 vs 11 or 13 vs 14). The formation of non-reductive cyclization products (3, 11, 14) requires an unusual apparent trans β-H elimination — some mechanistic possibilities that are consistent with the data are proposed.
THE IMPORTANCE OF NEBULAR CONTINUUM AND LINE EMISSION IN OBSERVATIONS OF YOUNG MASSIVE STAR CLUSTERS

In this spectroscopic study of infant massive star clusters, we find that continuum emission from ionized gas rivals the stellar luminosity at optical wavelengths. In addition, we find that nebular line emission is significant in many commonly used broadband Hubble Space Telescope (HST) filters including the F814W I-band, the F555W V-band, and the F435W B-band. Two young massive clusters (YMCs) in the nearby starburst galaxy NGC 4449 were targeted for follow-up spectroscopic observations after Reines et al. discovered an F814W I-band excess in their photometric study of radio-detected clusters in the galaxy. The spectra were obtained with the Dual Imaging Spectrograph (DIS) on the 3.5 m Apache Point Observatory (APO) telescope and have a spectral range of ~3800-9800 A. We supplement these data with HST and Sloan Digital Sky Survey photometry of the clusters. By comparing our data to the Starburst99 and GALEV evolutionary synthesis models, we find that nebular continuum emission competes with the stellar light in our observations and that the relative contribution from the nebular continuum is largest in the U- and I-bands, where the Balmer (3646 A) and Paschen jumps (8207 A) are located. The spectra also exhibit strong line emission including the [S III] λλ9069, 9532 lines in the HST F814W I-band. We find that the combination of nebular continuum and line emission can account for the F814W I-band excess previously found by Reines et al. In an effort to provide a benchmark for estimating the impact of ionized gas emission on photometric observations of young massive stellar populations, we compute the relative contributions of the stellar continuum, nebular continuum, and emission lines to the total observed flux of a 3 Myr old cluster through various HST filter/instrument combinations, including filters in the Wide Field Camera 3. We urge caution when comparing observations of YMCs to evolutionary synthesis models since nebular continuum and line emission can have a large impact on magnitudes and colors of young (5 Myr) clusters, significantly affecting inferred properties such as ages, masses and extinctions.
Serum Androgens: Associations With Prostate Cancer Risk and Hair Patterning

Cancer of the prostate is the leading cancer among American men, yet few risk factors have been established. Hair growth and development are influenced by androgens, and it has long been suspected that prostate cancer also is responsive to these hormones. A blinded, case-control study was undertaken to deter- mine if hair patterning is associated with risk of prostate cancer, as well as specific hormonal profiles. The study accrued 315 male sub- jects who were stratified with regard to age, race, and case-control status (159 prostate cancer cases/i 56 controls). Hair-patterning classification and serum levels of total and free testosterone (T), sex hormone binding globulin, and dihydrotestosterone (DHT) were per- formed. Data indicate that hair patterning did not differ between pros- tate cancer cases and controls; however, significant hormonal dif- ferences were detected between the two groups. Free T was greater among cases than in controls (16.4 ± 6.1 vs. 14.9 ± 4.8 pg/mI, P = 0.02). Conversely, DHT-related ratios were greater among con- trols (P = 0.03 for DHT/T and P = 0.01 for DHT/free T). Several strong associations also were found between hormone levels and hair patterning. Men with vertex and frontal baldness had higher lev- els of free T (16.5 ± 5.5 and 16.2 ± 8.0 pg/mI, respectively) when compared to men with either little or no hair loss (14.8 ± 4.7 pg/mI) (P = 0.01). Data suggest that increased levels of free T may be a risk factor for prostatic carcinoma. In addition, although no differ- ences in hair patterning were detected between cases and controls within this older population, further research (i.e., prospective trials or case-control studies among younger men) may be necessary to determine if hair patterning serves as a viable biornarker for this disease, especially given the strong association between free T lev- els and baldness.
An extended Hückel theory based atomistic model for graphene nanoelectronics

An atomistic model based on the spin-restricted extended Huckel theory (EHT) is presented for simulating electronic structure and I–V characteristics of graphene devices. The model is applied to zigzag and armchair graphene nano-ribbons (GNR) with and without hydrogen passivation, as well as for bilayer graphene. Further calculations are presented for electric fields in the nano-ribbon width direction and in the bilayer direction to show electronic structure modification. Finally, the EHT Hamiltonian and NEGF (Nonequilibrium Green’s function) formalism are used for a paramagnetic zigzag GNR to show 2e2/h quantum conductance.
Synthesis of Methoxynor Polyisoprenoid Alcohols by Alkylation of (3-Methoxyallyl)lithium Reagents

A series of six methyl enol ether analogs 8 - 13 of geraniol, ( E , E )-farnesol, and ( E , E , E )-geranylgeraniol was synthesized from a group of three allylic methyl ethers and three allylic chlorides. Lithiation of the 1-methyl-, or 1-alkenylvinyl ethers with sec -butyllithium at -78 °C followed by alkylations of the resulting ( Z )-(3-methoxyallyl)lithium reagents afforded the six possible Z-configured(trans) methoxynor polyprenyl benzyl ethers bearing the methoxy substituent at the internal and terminal double bonds with high Z/E ratios (5 : 1-31 : 1) and 47-80% yields. Reductive cleavage of the benzyl groups with lithium in liquid ammonia gave the corresponding methoxynor polyprenols. 11-Methoxy-18-nor and 7-methoxy-19-nor geranylgeraniols ( 13 and 12 ) were converted to the corresponding diphosphates, 7 and 32 , by the Poulter displacement method. The stability of the enol ether in 7 in aqueous solution at pH 8 was verified by NMR analyses. The diphosphates of the methoxynor polyprenols may prove useful as substrate analogs for terpene synthases to capture transient intermediates in cyclization reactions catalyzed by these enzymes.
Ferroelectric WO3 Nanoparticles for Acetone Selective Detection

Ferroelectric e-WO3 nanoparticles were synthesized and stabilized above room temperature for the first time. A sensor based on this material was found to be highly sensitive and selective to acetone gas which will serve as a good candidate for diabetes diagnosis based on human breath analysis.
Existence of relative periodic orbits near relative equilibria

We show existence of relative periodic orbits (a.k.a. relative nonlinear normal modes) near relative equilibria of a symmetric Hamiltonian system under an appropriate assumption on the Hessian of the Hamiltonian. This gives a relative version of the Moser-Weinstein theorem. The paper supersedes an earlier paper (this arxiv math.SG/9906007), which contains a mistake.
A Unifying Polyhedral Approximation Framework for Convex Optimization

We propose a unifying framework for polyhedral approximation in convex optimization. It subsumes classical methods, such as cutting plane and simplicial decomposition, but also includes new methods and new versions/extensions of old methods, such as a simplicial decomposition method for nondifferentiable optimization and a new piecewise linear approximation method for convex single commodity network flow problems. Our framework is based on an extended form of monotropic programming, a broadly applicable model, which includes as special cases Fenchel duality and Rockafellar's monotropic programming, and is characterized by an elegant and symmetric duality theory. Our algorithm combines flexibly outer and inner linearization of the cost function. The linearization is progressively refined by using primal and dual differentiation, and the roles of outer and inner linearization are reversed in a mathematically equivalent dual algorithm. We provide convergence results for the general case where outer and inner linearization are combined in the same algorithm.
Antibiotic Use in Animal Agriculture and the Economics of Resistance: Discussion

The organizers and authors of the papers in this session are to be congratulated for assembling a set of papers that provides an informative review and new analysis of an important policy issue. The issue of animal antibiotic use (AAU) is one of a growing list of important policy questions where there is a clear need to integrate biological and/or physical sciences with economics. Economists can contribute to the policy debate in a number of important ways: First, economists can define relevant policy options and assess their economic effects, both in terms of equity and efficiency. Second, economists can collaborate with other scientists to integrate biological and physical science relationships into economic analysis to quantify the benefits and costs of policy alternatives, including the range of uncertainty associated with those benefits and costs. Third, through collaborations with other scientists, economists can help define an agenda of policy-relevant science needed to reduce the range of uncertainty associated with policy alternatives. Economists can have a significant impact on policy if they provide information that decision makers find useful. To have an impact, economists must go beyond publishing theoretical refinements in economics journals; they must do the job of translating economics into the qualitative and quantitative terms that the general science and policy community can understand and use.
Synthesis of Functionalized α,α-Disubstituted β-Alkynyl Esters from Allenoates through an Alkynylenolate Intermediate

Highly substituted α,α-disubstituted β-alkynyl esters are readily prepared from allenyl esters and either alkyl halide, acid chloride, or alkyl chloroformate, mediated by an amide base. This highly efficient and mild process tolerates various functional groups and provides α,α-disubstituted β-alkynyl esters in good to excellent yields. This method is especially suitable for the synthesis of 1,n-enynes or 1,n-diynes (n > 4). Electrophilic cyclization of 1,5-enyne gives a highly functionalized γ-iodolactone, whereas its platinum-catalyzed cycloisomerization affords 1,3-cyclohexadiene.
Massless black hole pairs in string theory

Abstract We analyze the zero mass black holes that arise as classical solutions to low energy heterotic string theory. Though these solutions contain naked singularities, it has been conjectured that they should be allowed in the theory. We find a solution describing a pair of oppositely charged massless black holes in uniformly accelerated motion under no external force . By analytically continuing the solution to Euclidean time, we find an instanton mediating the pair production of these objects in Minkowski space. We analyze the creation rate, and discuss some consequences of the result.
An empirical process central limit theorem for dependent non-identically distributed random variables

Abstract This paper establishes a central limit theorem (CLT) for empirical processes indexed by smooth functions. The underlying random variables may be temporally dependent and non-identically distributed. In particular, the CLT holds for near epoch dependent (i.e., functions of mixing processes) triangular arrays, which include strong mixing arrays, among others. The results apply to classes of functions that have series expansions. The proof of the CLT is particularly simple; no chaining argument is required. The results can be used to establish the asymptotic normality of semiparametric estimators in time series contexts. An example is provided.
Unraveling molecular transformations on surfaces: a critical comparison of oxidation reactions on coinage metals

The coinage metals, copper, silver, and gold, have unique characteristics for selective oxidation catalysis, particularly for partial oxidation of alcohols and olefins. A basic understanding of surface chemistry at the molecular level can help facilitate the improvement of current catalytic processes and the designing of new catalytic systems. In this critical review, the current state of knowledge of these reactions is reviewed. First, both the experimental and theoretical methods necessary for understanding surface reactivity are discussed with a specific set of examples directly related to these reactions. Next the state of understanding of the surface chemistry of the oxidation reactions of alcohols and olefins on these three coinage metals is reviewed and the reaction pathways are compared. Clear relationships between the low pressure surface science studies and more practical catalytic conditions are illustrated. Finally, recent theoretical advances in this area are discussed as well as possible future directions in this field (132 references).
On The Formulation of Power Distribution Factors for Linear Load Flow Methods

Fast linear load flows used in contingency analysis, interchange studies and many optimization schemes often utilize power distribution factors. The success of many of these methods has hinged greatly on the use of the Z matrix reference to swing or an arbitrary ground tie. This paper furnishes a mathematical basis for these heuristic methods.
Improved Approach to the Streamline Curvature Method in Turbomachinery

Quasi three dimensional blade-to-blade solutions for stators and rotors of turbomachines are obtained using the Streamline Curvature Method (SLCM). The first-order velocity gradient equation of the SLCM, traditionally solved for the velocity field, is reformulated as a second-order elliptic differential equation and employed in tracing the streamtubes throughout the flow field. The equation of continuity is then used to calculate the velocity. The present method has the following advantages. First, it preserves the ellipticity of the flow field in the solution of the second-order velocity gradient equation. Second, it eliminates the need for curve fitting and strong smoothing under-relaxation in the classical SLCM. Third, the prediction of the stagnation streamlines is a straightforward matter which does not complicate the present procedure. Finally, body-fitted curvilinear coordinates (streamlines and orthogonals or quasi-orthogonals) are naturally generated in the method. Numerical solutions are obtained for inviscid incompressible flow in rotating and non-rotating passages and the results are compared with experimental data.
Reconstruction of an Inductive Velocity Field Vector from Doppler Motions and a Pair of Solar Vector Magnetograms

We outline a general methodology to infer the inductive velocity field vector in solar active regions. For the first time, both the field-aligned and the cross-field velocity components are reconstructed. The cross-field velocity solution accounts for the changes of the vertical magnetic field seen between a pair of successive active region vector magnetograms via the ideal induction equation. The field-aligned velocity is obtained using the Doppler velocity and the calculated cross-field velocity. Solving the ideal induction equation in vector magnetograms measured at a given altitude in the solar atmosphere is an underdetermined problem. In response, our general formalism allows the use of any additional constraint for the inductive cross-field velocity to enforce a unique solution in the induction equation. As a result, our methodology can give rise to new velocity solutions besides the one presented here. To constrain the induction equation, we use a special case of the minimum structure approximation that was introduced in previous studies and is already employed here to resolve the 180° ambiguity in the input vector magnetograms. We reconstruct the inductive velocity for three active regions, including NOAA AR 8210, for which previous results exist. Our solution believably reproduces the horizontal flow patterns in the studied active regions but breaks down in cases of localized rapid magnetic flux emergence or submergence. Alternative approximations and constraints are possible and can be accommodated into our general formalism.
How Norwegian managers view dividend policy

Abstract We survey managers of Norwegian firms listed on the Oslo Stock Exchange about their views on dividend policy. The key factors that drive dividend policies are the level of current and expected future earnings, stability of earnings, current degree of financial leverage, and liquidity constraints. No significant correlation exists between the overall rankings of factors influencing dividend policy between Norwegian and U.S. managers. Norwegian managers express mixed views about whether a firm's dividend policy affects firm value. In general, management views provide support for the signaling hypothesis of payout policy but not the tax-preference explanation.