cssi/SciSciGPT-SciSciNet huggingface dataset:
Acid fluorides and 1,1-difluoroethyl methyl ethers as new organic sources of fluoride for antimony pentachloride-catalyzed halogen-exchange reactions

Abstract 1,1-Difluoroethyl methyl ethers such as the commercial veterinary anesthetic methoxyflurane (2,2-dichoro-1,1-difluoroethyl methyl ether, 6 ) decompose in the presence of a catalytic amount of antimony pentachloride. The rate of decomposition is dependent upon the number and position of halogen atoms in the ether: a high degree of halogenation at the methyl group or at the 2-position of the ethyl group makes the ether less prone to decomposition. The decomposition products are acid fluorides and halogenated methanes. The fate of the antimony pentachloride is conversion to a fluorochloroantimony species which can be used in situ to selectively fluorinate a polychlorinated substrate. Thus, 1,2,2,2-tetrachloro-1-fluoroethyl methyl ether ( 1 ) is converted cleanly to the anesthetic compound 2,2,2-trichloro-1,1-difluoroethyl methyl ether ( 2 ) using 6 as the fluoride source, exploiting the difference in stability of 2 and 6 to the pentavalent antimony species. It is also demonstrated that the acid fluorides obtained from decomposition of the 1,1-difluoroethyl methyl ethers are fluoride sources for halex reactions.
Synthetic approach to malibatol A.

[reaction: see text] A synthetic approach to malibatol A featuring a novel benzofuran synthesis is described.
Ensemble Estimators for Multivariate Entropy Estimation

The problem of estimation of density functionals like entropy and mutual information has received much attention in the statistics and information theory communities. A large class of estimators of functionals of the probability density suffer from the curse of dimensionality, wherein the mean squared error decays increasingly slowly as a function of the sample size T as the dimension d of the samples increases. In particular, the rate is often glacially slow of order O(T-γ/d), where γ > 0 is a rate parameter. Examples of such estimators include kernel density estimators, k -nearest neighbor (k-NN) density estimators, k-NN entropy estimators, intrinsic dimension estimators, and other examples. In this paper, we propose a weighted affine combination of an ensemble of such estimators, where optimal weights can be chosen such that the weighted estimator converges at a much faster dimension invariant rate of O(T1). Furthermore, we show that these optimal weights can be determined by solving a convex optimization problem which can be performed offline and does not require training data. We illustrate the superior performance of our weighted estimator for two important applications: 1) estimating the Panter-Dite distortion-rate factor; and 2) estimating the Shannon entropy for testing the probability distribution of a random sample.
Political economy and the science of association: A suggested reconstruction of public choice through the alliance of the Vienna, Virginia, and Bloomington schools of political economy

We argue that in order to answer the challenges that James Buchanan put to contemporary political economists, a reconstruction of public choice theory building on the work of Buchanan, F.A. Hayek and Vincent Ostrom must take place. Absent such a reconstruction, and the significant challenges that Buchanan raised will continue to go unmet.
BrasilAgro: Organizational Architecture for a High-Performance Farming Corporation

This invited case study presents the business model and organizational architecture of BrasilAgro - a large-scale, farmland development and farming corporation in Brazil.
Improved thermal processing of MOS diodes on n-InP

Metal-insulator-InP diodes with Al, Ni, Au, and Pd were fabricated using improved surface passivation techniques. The I-V and barrier height data indicate that a thin thermal oxide between the metal/InP and proximity cap protection during the rapid thermal annealing of the ohmic contact, improve the surface properties as confirmed by deep-level transient spectroscopy, no surface trap being detected. The reactive metals Al and Ni gave a low barrier height due to the reduction of oxide and reaction with InP. The nonreactive metals Au and Pd gave a high barrier height. The modified thermionic emission theory and thermionic field emission theory can be used to explain the conduction mechanisms on Ni and Au MIS diodes. The PD MIS diode exhibited an excess current component at low forward bias, which may be due to interface states. >
The role of the Weibel instability at the reconnection jet front in relativistic pair plasma reconnection

The role of the Weibel instability is investigated for the first time in the context of the large-scale magnetic reconnection problem. A late-time evolution of magnetic reconnection in relativistic pair plasmas is demonstrated by particle-in-cell simulations. In the outflow regions, powerful reconnection jets pile up the magnetic fields and then a contact discontinuity appears there. Further downstream, it is found that the two-dimensional extension of the relativistic Weibel instability generates electromagnetic fields, which are comparable to the antiparallel or piled-up fields. In a microscopic viewpoint, the instability allows the plasma’s multiple interactions with the discontinuity. In a macroscopic viewpoint, the instability leads to rapid expansion of the current sheet and then the reconnection jet front further propagates into the downstream. Possible application to the three-dimensional case is briefly discussed.
Late-stage [18F]fluorination: new solutions to old problems

The last 2–3 years have seen numerous relationships develop between organometallic chemists, fluorine chemists and PET Centers around the world. These collaborations have led to the development of many new strategies for the late-stage introduction of fluorine-18 into complex bioactive molecules. In this perspective we highlight recent developments and key milestones since 2011.
Evaluation of a Method for Heat Transfer Measurements and Thermal Visualization Using a Composite of a Heater Element and Liquid Crystals

Commercially available elements of a composite consisting of a plastic sheet coated with liquid crystal, another sheet with a thin layer of a conducting material (gold or carbon), and copper bus bar strips were evaluated and found to provide a simple, convenient, accurate, and low-cost measuring device for use in heat transfer research. The particular feature of the composite is its ability to obtain local heat transfer coefficients and isotherm patterns that provide visual evaluation of the thermal performances of turbine blade cooling configurations. Examples of the use of the composite are presented.
Job characteristics of research and development personnel: Relationships with satisfaction and role variables

Four core dimensions (variety, autonomy, task identity, feedback) and two interpersonal dimensions (dealing with others and friendship opportunities) of job characteristics were studied in a sample of 363 research and development professional personnel. It was hypothesized that the core dimensions would be positively related to intrinsic job satisfaction, while the interpersonal dimensions were hypothesized to be positively related to socially derived satisfactions. These hypotheses were supported by data from the total sample. All job characteristics were also hypothesized to be negatively related to role conflict and ambiguity. The data from the total sample supported this hypothesis fully with regard to role ambiguity, but only partially with regard to role conflict. Data were also separated and analyzed for supervisors and nonsupervisors. Implication for the management of research and development personnel are included.
On the Role of Irradiation and Evaporation in Strongly Irradiated Accretion Disks in the Black Hole X-Ray Binaries: Toward an Understanding of FREDs and Secondary Maxima

We examine a new paradigm to account for the exponential decay seen in the light curves of some of the bright X-ray novae. These systems show an exponential decay in soft X-rays with an e-folding time constant of ~30 days. We investigate a scenario in which evaporation of matter into a corona is the dominant mass removal mechanism from the accretion disk. We utilize the thermal evaporative instability discovered by Shaviv & Wehrse. First we parametrize local mass-loss rates from the disk (fitted to vertical structure computations of the optically thin structure using the photoionization code CLOUDY), and then we utilize the scalings in our numerical time-dependent model for the decay. Both the ~30 day e-folding timescale for the decay and the secondary maximum with its rapid rise time of ~1-3 days which is seen in the X-ray nova light curves can be produced by adjusting the strength of the evaporation.
Networks in Public Administration: Current scholarship in review

Abstract Network-focused research in public administration has expanded rapidly over the past two decades. This rapid growth has created come confusion about terminology and approaches to research in the field. We organize the network literature in public administration using compact citation networks to identify coherent subdomains focused on (1) policy formation, (2) governance and (3) policy implementation. We trace how these domains differ in their approach to defining the role of networks, relationships and actors and to what extent the articles apply formal network analysis techniques. Based on a subsequent content analysis of the sample articles, we identify promising research avenues focused on the wider adoption of methods derived from social network analysis and the conditions under which networks actually deliver improved results.
ON THE AFFINENESS OF DELIGNE-LUSZTIG VARIETIES

Abstract We prove that the Deligne–Lusztig variety associated to minimal length elements in any δ -conjugacy class of the Weyl group is affine, which was conjectured by Orlik and Rapoport in [S. Orlik, M. Rapoport, Deligne–Lusztig varieties and period domains over finite fields, arXiv: 0705.1646 ].
The diffusion of IT in higher education: publishing productivity of academic life scientists

This study investigates how the diffusion of Internet access and other advancements in IT across a broad group of institutions of higher education has affected the publishing productivity of life scientists. Several IT indicators are considered: (1) the adoption of BITNET; (2) the registration of domain names (DNS); (3) the availability of the electronic journal database, JSTOR (http://www.jstor.org/), and (4) the availability of electronic library resources. Data on life scientists are from the 1983, 1995, 2001 and 2003 Survey of Doctorate Recipients (SDR). Educational institutions are classified into tiers depending upon research intensity. Three hypotheses are tested: (1) IT enhances the careers of faculty; (2) IT improves the careers of faculty at lower-tiered relative to higher-tiered institutions; and (3) IT increases women's publication rates relative to those of men. The results provide some support for the first two hypotheses but no support for the third hypothesis.
Synthesis of a series of brominated 1-phenyl-2-pyridylethenes as inhibitors of the protein-tyrosine kinase p56lck

Abstract A series of brominated 1-phenyl-2-pyridylethenes was prepared and tested for inhibition of p56lck, a protein-tyrosine kinase of the src family which is overexpressed in several lymphomas. The most potent compound of the series proved to be 2-(3,5-dibromo-4-hydroxybenzylidene)-2-(2-pyridyly)acetonitrile (3).
Thermal residual stress evolution in a TiC-50vol.% Ni3Al cermet

Abstract Volume averaged thermal residual stresses in a TiC–50 vol.% Ni3Al cermet were measured over a temperature range from room temperature to about l250 K using in situ neutron diffraction. At room temperature, the thermal residual stresses in both the Ni3Al binder and the TiC particles were about 1.6 GPa. In the temperature range studied, the residual stress exhibited primarily elastic behavior during heating, followed by a non-linear cooling. The path dependency is attributed to a limited plastic flow and severe strain hardening in the Ni3Al binder phase below 900 K during cooling. Furthermore, the isothermal annealing of the cermet at l250 K for 10 h did not show any creep relaxation of residual stresses or development of interfacial phases. An elastic finite-element model was developed which approximately predicts the thermal residual stress evolution in the TiC–50 vol.% Ni3Al cermet studied.
The effect of binarity on stellar rotation : Beyond the reach of tides

We present a comparison between the rotation period distributions of solar-type single stars and primary stars in close binaries (0.1 AU a 5 AU) in the young (~150 Myr) open cluster M35 (NGC 2168). We find that the primary stars in the close binaries rotate faster than the single stars, on average. The differences in the means and medians between the period distributions are statistically significant at the 99.9% level or higher. The faster rotation among the primary stars in close binaries is not due to tidal synchronization as tidally evolved stars are excluded from the comparison. We discuss this result in the context of different early-evolution accretion processes and star-disk interactions for single stars and stars in close binaries.
Accurate spectral estimation from unequally spaced samples of exponentially damped sinusoidal signals

A method is presented to interpolate and extrapolate unequally spaced signals that are not bandlimited. This is achieved by utilizing the Gregory-Newton quadrature formula which circumvents aliasing without bandlimiting. With the Gregory-Newton quadrature formula, it is possible to compute the Fourier spectrum of the unequally spaced signals, which is not bandlimited. The effect of noise on the Gregory-Newton quadrature formula is observed. Specifically, the quality of interpolation, extrapolation, and the spectrum as a function of various signal-to-noise ratios is observed. This may be a useful technique for computing unaliased spectra of unequally spaced, damped sinusoidal signals having a signal-to-noise ratio greater than 20 dB.
Synthesis of a 2-deoxy-ribose type 1-N-iminosugar

Abstract A 2-deoxy-ribose-type 1-N-iminosugar 5 was synthesized, in multi-gram scale, from fumaric acid monoethyl ester employing Sharpless asymmetric epoxidation followed by a Lewis acid-catalyzed (Yamammoto's aluminum reagent) cyanide epoxy ring-opening reactions.
“I see smart people!”: Using Facebook to supplement cognitive and affective learning in the university mass lecture

Abstract Mass lecture courses are a mainstay in university instruction despite their limitations regarding student engagement and resultant learning outcomes. Out-of-class communications and learning management systems have been developed to address these limitations, but the former is resource-intensive and the latter is often viewed as an administrative rather than pedagogical aid. Facebook groups have proven to be useful and persistent spaces for connecting individuals around innumerable topics of interest. In this study, a course-specific Facebook group was created for an introductory mass media course at a large mid-Atlantic university to serve as a supplemental (and voluntary) space for course content discussions. End-of-the semester grades of the Facebook group users were significantly higher than the non-users, t (319) = 4.71, p
High-pressure steam engines and computer software

The introduction of computers into the control of potentially dangerous devices has led to a growing awareness of the possible contribution of software to serious accidents. The number of computer-related accidents so far has been small due to the restraint shown in introducing computers into safety-critical control loops. However, as the economic and technological benefits of using computers become more widely accepted, their use is increasing dramatically. We need to ensure that computers are introduced into safety-critical systems in the most responsible way possible and at a speed that does not expose people to undue risk. Risk induced by technological innovation existed long before computers; this is not the first time that humans have come up with an extremely useful new technology that is potentially dangerous. Studying parallels in the early development of high-pressure steam engines and of software engineering can help. >
Direct Michael Addition of Alkenes via a Cobalt-Dinitrosyl Mediated Vinylic C–H Functionalization Reaction

We report a one-pot, direct C–H functionalization reaction of alkenes mediated by [CpCo(NO)2]. All intermediates in the proposed reaction sequence have been characterized. A variety of Michael acceptors can be utilized with the one-pot procedure to give the desired cyclic tetra-alkyl-substituted, γ,δ-unsaturated compounds in good yields. We also provide a preliminary result for catalytic turnover in both base and [CpCo(NO)2].
Circular dichroism studies of bisindole Vinca alkaloids

Abstract The analysis of a series of seventeen vinblastine analogs by circular dichroism is described. Exciton coupling of the indole and indoline chromophores of these compounds provides a general, non-empirical method for the assignment of the C16′ configuration with the bioactive C16′-S and the inactive C16′-R analogs giving rise, respectively, to positive and negative couplets. An analysis of the non-coupled transitions of the CDs indicates that a positive Cotton effect at 305 nm, although empirical, is associated with bioactivity. Theoretical calculations of the UV and CD spectra of vinblastine diastereomers are also described.
New screening methodology for selection of polymeric materials for transdermal drug delivery devices

Transdermal drug delivery systems, such as patches, are viewed as one the best technologies that enhance greater patient compliance thus providing the desired therapeutic results. However, one of the main challenges is to find the right polymeric matrix that will provide the desired active therapeutic concentration. This is usually accomplished empirically and is not always the effective approach. In this study, the authors describe a predictive screening methodology based on material parameters to identify materials that will accomplish therapeutic targets.
Starburst-like Dust Extinction in the Small Magellanic Cloud

The recent discovery that the ultraviolet (UV) dust extinction in starburst galaxies is similar to that found in the Small Magellanic Cloud (SMC) motivated us to reinvestigate the UV extinction found in the SMC. We have been able to improve significantly on previous studies by carefully choosing pairs of well-matched reddened and unreddened stars. In addition, we benefited from the improved signal-to-noise ratio of the NEWSIPS International Ultraviolet Explorer (IUE) data and the larger sample of SMC stars now available. Searching the IUE Final Archive, we found only four suitable early-type stars that were significantly reddened and had well-matched comparison stars. The extinction for three of these stars is remarkably similar. The curves are roughly linear with λ-1 and have no measurable 2175 A bump. The fourth star has an extinction curve with a significant 2175 A bump and weaker far-UV extinction. The dust along all four sight lines is thought to be local to the SMC. There is no significant Galactic foreground component. The first three stars lie in the SMC bar, and the line of sight for each of them passes through regions of recent star formation. The fourth star belongs to the SMC wing, and its line of sight passes through a much more quiescent region. Thus, the behavior of the dust extinction in the SMC supports a dependence of dust properties on star formation activity. However, other environmental factors (such as galactic metallicity) must also be important. Dust in the 30 Dor region of the LMC, where much more active star formation is present, does not share the extreme extinction properties seen in SMC dust.
Government, clubs, and constitutions

Abstract This paper analyzes “constitutional effectiveness” – the degree to which constitutions can be enforced – in the system of government vs. the system of clubs. I argue that clubs have residual claimants on revenues generated through constitutional compliance, operate in a highly competitive environment, and permit individuals to sort themselves according to their governance needs. These features make their constitutional contracts self-enforcing. Government lacks these features. So its constitutional contract is not. Institutional augmentations that make government more club-like, such as federalism, democracy, and limited government scope, improve government's constitutional effectiveness. But constitutional effectiveness remains superior in the system of clubs.
The martian Hadley circulation: comparison of « viscous» model predictions to observations

A comparison is conducted between the results of an analytical, steady, thermally-forced viscous model for the Martian atmosphere's zonally-averaged global circulation and observations of aeolian feature directions and atmospheric temperatures. While the observed northeasterly surface winds at high northern latitudes could be produced by possible CO2 fluxes from the northern polar cap, and southern latitudes' thermal structure during this storm is well reproduced, a major discrepancy is noted between predictions and observations of the middle northern latitudes' temperature structure.
Plasmon-Mediated Syntheses of Metallic Nanostructures

The ability to prepare noble metal nanostructures of a desired composition, size, and shape enables their resulting properties to be exquisitely tailored, which has led to the use of these structures in numerous applications, ranging from medicine to electronics. The prospect of using light to guide nanoparticle reactions is extremely attractive since one can, in principle, regulate particle growth based on the ability of the nanostructures to absorb a specific excitation wavelength. Therefore, using the nature of light, one can generate a homogenous population of product nanoparticles from a heterogeneous starting population. The best example of this is afforded by plasmon-mediated syntheses of metal nanoparticles, which use visible light irradiation and plasmon excitation to drive the chemical reduction of Ag+ by citrate. Since the initial discovery that Ag triangular prisms could be prepared by the photo-induced conversion of Ag spherical nanoparticles, plasmon-mediated synthesis has become a highly controllable technique for preparing a number of different Ag particles with tight control over shape, as well as a wide variety of Au-Ag bimetallic nanostructures. We discuss the underlying physical and chemical factors that drive structural selection and conclude by outlining some of the important design considerations for controlling particle shape as learned through studies of plasmon-mediated reactions, but applicable to all methods of noble metal nanocrystal synthesis.
Lamellar reaction phenomena: from intercalation to nanomaterials formation

Abstract Lamellar reaction processes govern the formation and properties of a wide range of materials of fundamental and technological interest, offering the potential to control the structure, composition and dimension of materials down to the nanoscale. Environmental transmission electron microscopy, complementary investigations, and atomistic modeling have been combined to explore the mechanisms that control these processes. Model transition metal disulfide (e.g. TS 2 , T=Ti,Ta) intercalation/deintercalation and lamellar hydroxide (e.g. Mg(OH) 2 ) dehydroxylation/rehydroxylation reaction processes are compared to probe the effect of relatively strong and weak/transitory intralayer bonding on lamellar reaction processes. Intriguing similarities are observed even though the hydroxide lamella are destroyed and reform during dehydroxylation and rehydroxylation processes, respectively. Deintercalation and dehydroxylation occur via analogous empty gallery and oxide layer formation. Both processes generally progress via lamellar nucleation and growth, with growth progressing away from the lamellar nucleation site. Similarities extend to stage formation, with random/‘stage-2-like’ oxide and hydroxide layer ordering occurring in the lamellar oxyhydroxide regions that form. In contrast to stable host layers associated with intercalation processes, relatively weak/transitory intralayer bonding associated with lamellar dehydroxylation/rehydroxylation processes facilitates layer delamination, shearing, cracking, and nanoreconstruction during dehydroxylation, and, nanocrystal formation, intergrowth and the rapid ‘annealing out’ of lamellar defects that form during rehydroxylation.
An optimal algorithm for intersecting line segments in the plane

The main contribution of this work is an O(n log n + k)-time algorithm for computing all k intersections among n line segments in the plane. This time complexity is easily shown to be optimal. Within the same asymptotic cost, our algorithm can also construct the subdivision of the plane defined by the segments and compute which segment (if any) lies right above (or below) each intersection and each endpoint. The algorithm has been implemented and performs very well. The storage requirement is on the order of n + k in the worst case, but it is considerably lower in practice. To analyze the complexity of the algorithm, an amortization argument based on a new combinatorial theorem on line arrangements is used.
Lower mantle heterogeneity, dynamic topography and the geoid

Density contrasts in the lower mantle, inferred using seismic tomography, drive viscous flow; this results in kilometres of dynamically maintained topography at the core–mantle boundary and at the Earth's surface. The total gravity field due to interior density contrasts and dynamic boundary topography predicts the longest-wavelength components of the geoid remarkably well. Neglecting dynamic surface deformation leads to geoid anomalies of opposite sign to those observed.
A Convenient One-Step Synthesis of 2-Hydroxy-1,3,5-Benzenetricarbaldehyde

Abstract The hexamethylenetetramine/trifluoroacetic acid system was demonstrated to be capable of introducing three aldehyde groups into the phenol molecule. Facile, one-step procedures were developed for the preparation of hitherto difficult to synthesize 2-hydroxy-1,3,5-benzenetricarbaldehyde starting from either phenol or 4-hydroxybenzaldehyde. New pKa measurements showed 2-hydroxy-1,3,5-benzenetricarbaldehyde to be an acid stronger than previously reported.
A survey of Mg II h and k emission in near-solar-type stars

Mesures par le satellite IUE des flux d'emission Mg II h et k pour 30 etoiles F et G et comparaison avec les mesures de flux CaII H et K obtenus par Wilson pour ces etoiles
Synthesis of novel 4-amino-1,4-benzodiazepine-2,5-diones for anticonvulsant testing

A series of novel 4-amino-1,4-benzodiazepine-2,5-diones was synthesized via two pathways. The first method involved reductive alkylation of unsymmetrical hydrazines with glyoxylic acid, followed by Fisher esterification. The resulting N-aminoglycinate ethyl ester was subsequently o-nitrobenzoylated, reduced, and thermally cyclized to obtain 4-dialkylaminobenzodiazepinones. In the second method methylhydrazine was acetylated at Nα then benzoylated at Nβ to give 1,2-diacylhydrazines. Alkylation with ethyl bromoacetate and reduction of the nitro group, followed by thermal cyclization yielded 4-acetamidobenzodiazepinones. All title compounds were evaluated in mice in MES seizure and sc Met seizure threshold tests for anticonvulsant activity, and in the rotorod test for neurotoxicity. Activity and toxicity were both minimal.
Restricted Covariance Priors with Applications in Spatial Statistics.

We present a Bayesian model for area-level count data that uses Gaussian random effects with a novel type of G-Wishart prior on the inverse variance–covariance matrix. Specifically, we introduce a new distribution called the truncated G-Wishart distribution that has support over precision matrices that lead to positive associations between the random effects of neighboring regions while preserving conditional independence of non-neighboring regions. We describe Markov chain Monte Carlo sampling algorithms for the truncated G-Wishart prior in a disease mapping context and compare our results to Bayesian hierarchical models based on intrinsic autoregression priors. A simulation study illustrates that using the truncated G-Wishart prior improves over the intrinsic autoregressive priors when there are discontinuities in the disease risk surface. The new model is applied to an analysis of cancer incidence data in Washington State.
Sulfur p-band hole generation in β-BaCu2S2. Synthesis of metallic KxBa1-xCu2S2 from molten mixed K-Ba polysulfide salts

Abstract The reaction of Cu with molten mixed polysulfide K 2−2 x Ba x S y flux produced K x Ba 1− x Cu 2 S 2 0.1 x ⩽ 0.4 at 450°C. Crystal data for K 36 Ba 64 Cu 2 S 2 at 23°C (Mo Kα radiation): a = 3.890(1) A ; c = 12.753(3) A ; V = 192.9(1) A 3 ; Z = 1; d calc = 5.055 g cm −3 ; space group I4 mmm (no. 139); 2 θ max = 80°; Mo Kα radiation; number of data collected, 545; number of independent data, 307; independent data observed with I > 3 σ ( I ), 196; number of variables, 8; μ = 187.02 cm −1 ; final R = 0.034; R w = 0.047; goodness-of-fit = 2.32. The structure is isomorphous to that of β-BaCu 2 S 2 (or the well-known ThCr 2 Si 2 structure), with anti-PbO type [Cu 2 S 2 ] slabs and a statistical disorder between K + −Ba 2+ ions. Substitution of K + cation for Ba 2+ gives rise to mixed valency and a p-type metallic compound. Charge transport properties are reported.
Waiting for Superleader: leadership as anti-resource discourse

The purpose of this conceptual paper is to explore the constructs of school leadership that have gained primacy over the past 20 years. In doing so, I discuss how structures limit the role of the leader in school organisations has been overlooked, particularly ignoring the resource dependency of schools and the external control of resources they do acquire. What I argue is that leadership is an anti-resource discourse. That is, the focus on leadership allows the neoliberal discourse to ignore and obscure the inequitable funding of schools in the USA.
An improved upper bound for the bondage number of graphs on surfaces

Abstract The bondage number b ( G ) of a graph G is the smallest number of edges whose removal from G results in a graph with larger domination number. Recently Gagarin and Zverovich showed that, for a graph G with maximum degree Δ ( G ) and embeddable on an orientable surface of genus h and a non-orientable surface of genus k , b ( G ) ≤ min { Δ ( G ) + h + 2 , Δ + k + 1 } . They also gave examples showing that adjustments of their proofs implicitly provide better results for larger values of h and k . In this paper we establish an improved explicit upper bound for b ( G ) , using the Euler characteristic χ instead of the genera h and k , with the relations χ = 2 − 2 h and χ = 2 − k . We show that b ( G ) ≤ Δ ( G ) + ⌊ r ⌋ for the case χ ≤ 0 (i.e. h ≥ 1 or k ≥ 2 ), where r is the largest real root of the cubic equation z 3 + 2 z 2 + ( 6 χ − 7 ) z + 18 χ − 24 = 0 . Our proof is based on the technique developed by Carlson–Develin and Gagarin–Zverovich, and includes some elementary calculus as a new ingredient. We also find an asymptotically equivalent result b ( G ) ≤ Δ ( G ) + ⌈ 12 − 6 χ − 1 / 2 ⌉ for χ ≤ 0 , and a further improvement for graphs with large girth.
How well can people use different color attributes

Two psychophysical experiments were conducted to analyze the role of color attributes in simple tasks involving color matching and discrimination. In Experiment I observers made color matches using three different adjustment control methods. The results showed that the Lightness, Chroma, Hue (LCH) and the Lightness, redness/greenness, blueness/yellowness ({L, r/g, y/b}) adjustment controls elicited significantly better performance than the display RGB controls in terms of both accuracy and time, but were not significantly different from each other. Expert observers performed significantly better than naive observers in terms of accuracy. Experiment II was a replication and extension of the experiment by Melgosa et al. [Color Res Appl 2000; 25: 356–367] in which observers judged differences and similarities for color attributes in pairs of colored patches. At a 95% confidence level, the results from judging difference were significantly better than those from judging similarity. Hue and Lightness were significantly more identifiable than Chroma, r/g, and y/b. These results indicate that people do not have ready access to the lower level color descriptors such as the common attributes used to define color spaces, and that higher level psychological processing involving cognition and language may be necessary for even apparently simple tasks involving color matching and describing color differences. © 2006 Wiley Periodicals, Inc. Col Res Appl, 31, 445–457, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20257
Relativistic magnetospheric electrons: Lower ionospheric conductivity and long-term atmospheric variability

Abstract Long-term (1979–88) observations of relativistic electrons in the earth's outer magnetosphere show a strong solar cycle dependence with a prominent intensity maximum during the approach to solar minimum (1983–85). This population therefore corresponds to the presence of high-speed solar wind streams emanating from solar coronal holes. Using a numerical code, we have calculated the precipitating electron energy deposition in the earth's upper and middle atmosphere. Observed events (typically persisting several days) would have maximum effect in the 40–60 km altitude range. We suggest that this electron population could play an important long-term role in modulating lower D-region ionization and middle atmospheric ozone chemistry. We describe methods of observing middle atmospheric and lower ionospheric effects of the electrons. A particularly promising approach may involve the monitoring of global Schumann resonance modes which are sensitive to global changes in the properties of the earth-ionosphere cavity. Ongoing work indicates that Schumann resonance properties are moderately correlated with the flux of precipitating relativistic electrons thus offering the possibility of continuously monitoring this aspect of magnetosphere-atmosphere coupling.
Redox-Neutral α-C–H Bond Functionalization of Secondary Amines with Concurrent C–P Bond Formation/N-Alkylation

Redox-neutral formation of C–P bonds in the α-position of amines was achieved via a process that features a combination of an oxidative α-C–H bond functionalization and a reductive N-alkylation. Benzoic acid functions as an efficient catalyst in this three-component reaction of cyclic secondary amines, aldehydes and phosphine oxides to provide rapid access to α-amino phosphine oxides not easily accessible by classic Kabachnik–Fields reactions.
Enhanced ionic conductivity in composite electrolytes

Abstract Formation of a space-charge layer around the alumina particles cannot account for the large enhanced ionic conductivity reported for several composite materials. Conductivity studies of AgCl-alumina fiber composites demonstrate that the enhanced conductivity path is not confined to a layer along the alumina interface. The enhanced conduction is correlated with the presence of grain boundaries or dislocations formed by plastic deformation and primary recrystallization of the AgCl. The most important role of the alumina fibers or particles is to limit the grain size of the AgCl and stabilize the more highly conductive polycrystalline microstructure.
EVIDENCE FOR ACCRETION IN THE HIGH-RESOLUTION X-RAY SPECTRUM OF THE T TAURI STAR SYSTEM Hen 3-600

We present high-resolution X-ray spectra of the nearby multiple T Tauri star (TTS) system Hen 3-600, obtained with the High Energy Transmission Grating Spectrograph (HETGS) aboard the Chandra X-Ray Observatory. Both principal binary components of Hen 3-600 (A and B, separation 1.4'') were detected in the zeroth-order Chandra HETGS X-ray image. Hen 3-600-A, the component with a large mid-infrared excess, is a factor of ~2-3 fainter in X-rays than Hen 3-600-B, due to a large flare at Hen 3-600-B during our observation. The dispersed X-ray spectra of the two primary components overlap significantly, so spectral analysis was performed primarily on the first-order spectrum of the combined A + B system, with analysis of the individual dispersed spectra limited to regions where the contributions of A and B can be disentangled via cross-dispersion profile fitting. This analysis results in two lines of evidence indicating that the X-ray emission from Hen 3-600 A + B is derived, in part, from accretion processes. (1) The line ratios of He-like O VII in the spectrum of Hen 3-600 A + B indicate that the characteristic density of its X-ray-emitting plasma is significantly larger than those of coronally active main-sequence and pre-main-sequence stars. (2) A significant component of low-temperature (2-3 MK) plasma is present in the Hen 3-600 A + B spectrum; this "soft excess" appears somewhat stronger in component A. These results for Hen 3-600 A + B are consistent with, although less pronounced than, results obtained from X-ray grating spectroscopy of more rapidly accreting TTS systems. Indeed, all of the emission signatures of Hen 3-600 A + B that are potential diagnostics of accretion activity—from its high-resolution X-ray spectrum, through its UV excess and Hα emission-line strengths, to its weak near-infrared excess—suggest that its components (and component A in particular) represent a transition phase between rapidly accreting, classical T Tauri stars and nonaccreting, weak-lined T Tauri stars.
Structure of the Gluon Propagator at Finite Temperature

Abstract The thermal self-energy of gluons generally depends on four Lorentz-invariant functions when the gauge-fixing condition is rotationally invariant. Only two of these occur in the hard thermal loop approximation of Braaten and Pisarski because of the abelian Ward identity K μ Π μν htl =0. For the exact self-energy it is known that K μ Π μν ≠0 and that the Slavnov–Taylor identity requires a non-linear relation among three of the Lorentz-invariant self-energy functions: ( Π C ) 2 =( K 2 − Π L ) Π D . This relation simplifies the exact gluon propagator to a form containing only two types of poles: one that determines the behavior of transverse electric and magnetic gluons and one that controls the longitudinally polarized electric gluons. It agrees with known cases in the literature.
Solar Wind Speed and Temperature Outside 10 AU and the Termination Shock

In this paper we first present a series of pickup proton solar wind solutions following the fluid motion in the upwind direction to show that the wind speed V and temperature T, at a given r outside 10 AU, are primarily functions of the 1 AU wind speed V0. This relationship is attributed to the accumulated effects of the pickup proton process on the heating and deceleration of the solar wind. Because pickup protons are expected to have similar effects on the solar wind at all latitudes in the upwind side of the heliosphere, in the second part of the paper, the two formulae V(r, V0) and T(r, V0) are extended to study the termination shock at 35° latitude. Wang and Sheeley have an empirical model for calculating the 1 AU wind speed V0 from the observed photospheric field. We use the simulated wind speed V0 to calculate V and T outside 60 AU following the fluid motion; then we can study the solar cycle variation of the termination shock. The shock location near 35° is unambiguously dependent on the solar cycle, with a period of approximately 1 solar cycle; the amplitude for variation of the shock location is greater than 50 AU. The new result supports the idea that the first encounter of Voyager 1 with the termination shock may occur during the declining phase of cycle 23. After the first encounter, the spacecraft will cross the shock two more times over a period of 8 years.
Improving the Flexural Modulus and Thermal Stability of Pitch by the Addition of Silica Fume

The effects of sand and silica fume on the flexural modulus and thermal stability of pitch were investigated mechanically and thermomechanically. Both modulus and softening temperature were increased by sand addition and further increased by the further addition of silica fume, except that an excessive amount of silica fume caused the modulus to decrease. An effective composition involved 29 vol.% sand and 2 vol.% silica fume.
On the Quantum Symmetry of the Chiral Ising Model

Abstract We introduce the notion of rational Hopf algebras that we think are able to describe the superselection symmetries of rational quantum field theories. As an example we show that a six-dimensional rational Hopf algebra H can reproduce the fusion rules, the conformal weights, the quantum dimensions and the representation of the modular group of the chiral Ising model. H plays the role of the global symmetry algebra of the chiral Ising model in the following sense: (1) a simple field algebra F and a representation π on H π of it is given, which contains the c = 1 2 unitary representations of the Virasoro algebra as subrepresentations; (2) the embedding U: H → B ( H π ) is such that the observable algebra π( A ) − is the invariant subalgebra of B ( H π) with respect to the left adjoint action of H and U(H) is the commutant of π( A ); (3) there exist H-covariant primary fields in B ( H π), which obey generalized Cuntz algebra properties and intertwine between the inequivalent sectors of the observables.
Cu(II)-catalyzed olefin migration and Prins cyclization: highly diastereoselective synthesis of substituted tetrahydropyrans.

Metal–ligand complexes of Cu(OTf)2 with an appropriate bisphosphine ligand have been shown to effectively catalyze the formation of substituted tetrahydropyrans via a sequential olefin migration and Prins-type cyclization. This methodology provides convenient access to a variety of functionalized tetrahydropyrans in excellent diastereoselectivities and good to excellent yields.
Anisotropy of the Electronic Work Function of Metals

Work function is experimentally known to be different for different faces of a crystal by amounts ranging from one-tenth to half a volt. For tungsten the faces can be arranged according to decreasing work function as follows: 110, 211, 100 and finally 111. The explanations so far suggested for the differences of the work function are discussed and shown to give either an incorrect sequence or a wrong order of magnitude of the observed differences. The author uses the picture of Wigner and Bardeen according to which the work function is a sum of a volume contribution and a contribution due to a double layer on the surface of the metal. The origin of the latter can be described in the following manner. With every atom one can associate a polyhedron ("$s$-polyhedron") with the atom at its center, such that it contains all points nearer to the atom under consideration than to any other atom. If the distribution of the electron density within these polyhedra of the surface atoms was the same as for the inside atoms then there would be no double layer on the surface. However, this is not the case since the total energy is lowered by a redistribution of the electron cloud on the surface. There are two effects: the first is a partial spread of the charge out of the $s$-polyhedra and the second is a tendency to smooth out the surface of the polyhedra. In consequence of the second effect the surfaces of equal charge density are more nearly plane than in the original picture. The two effects have opposite influences and since they are comparable in magnitude, it is not possible to predict the sign of the total double layer without numerical computations. Some general formulae for the double layers are derived and discussed more fully in the case of a simple cubic and a body-centered cubic lattice. The minimum problem of the surface energy is solved for four faces of a body-centered crystal and the results are applied to the case of tungsten. One obtains the differences between the work functions for different directions. The results agree satisfactorily with the experimental data: assuming a reasonable density of the free electrons, one obtains the correct sequence of faces and the correct differences of the work function. The surface energies are calculated an d found in agreement with the observed stability of certain crystal faces.
Observing an Induced-fit Mechanism during Sequence-specific DNA Methylation

The characterization of conformational changes that drive induced-fit mechanisms and their quantitative importance to enzyme specificity are essential for a full understanding of enzyme function. Here, we report on M.HhaI, a sequence-specific DNA cytosine C5 methyltransferase that reorganizes a flexible loop (residues 80-100) upon binding cognate DNA as part of an induced-fit mechanism. To directly observe this ∼26A conformational rearrangement and provide a basis for understanding its importance to specificity, we replaced loop residues Lys-91 and Glu-94 with tryptophans. The double mutants W41F/K91W and W41F/E94W are relatively unperturbed in kinetic and thermodynamic properties. W41F/E94W shows DNA sequence-dependent changes in fluorescence: significant changes in equilibrium and transient state fluorescence that occur when the enzyme binds cognate DNA are absent with nonspecific DNA. These real-time, solution-based results provide direct evidence that binding to cognate DNA induces loop reorganization into the closed conformer, resulting in the correct assembly of the active site. We propose that M.HhaI scans nonspecific DNA in the loop-open conformer and rearranges to the closed form once the cognate site is recognized. The fluorescence data exclude mechanisms in which loop motion precedes base flipping, and we show loop rearrangements are directly coupled to base flipping, because the sequential removal of single hydrogen bonds within the target guanosine:cytosine base pair results in corresponding changes in loop motion.
Graphene-Based Nanoarchitectures. Anchoring Semiconductor and Metal Nanoparticles on a Two-Dimensional Carbon Support

Graphene based two-dimensional carbon nanostructures serve as a support to disperse catalyst nanoparticles. Reduced graphene oxide is used as a support to anchor semiconductor and metal nanoparticles. Such a design strategy would enable the development of a multifunctional catalyst mat. This Perspective focuses on the interaction between graphene oxide−semiconductor (TiO2, ZnO) and graphene oxide−metal (Au, Pt) nanoparticles and discusses potential applications in catalysis, light energy conversion, and fuel cells.
The Association of Jet Production with Geometrically Thick Accretion Flows and Black Hole Rotation

A model is presented in which the strongest radio-emitting jet outflows are produced in black hole systems when the accretion is a geometrically thick (H/R ~ 1) inflow (e.g., an advection-dominated or a convection-dominated accretion flow) and if the black hole is rotating. For galactic black hole candidates, the model naturally accounts for the observed correlation of jet outflow with the black hole hard emission state and predicts an association of strong jets with rapid black hole rotation. When extended to the supermassive case, the model accounts for the highest radio galaxy and quasar jet powers and provides additional theoretical support for the "spin paradigm," which asserts that radio-loud quasars are produced by Kerr holes and radio-quiet ones by Schwarzschild holes. In some cases, the angular momentum and energy outflow in the jet may be large enough to alter significantly the structure of the accretion flow from that predicted by current models.