cssi/SciSciGPT-SciSciNet huggingface dataset:
Functionalized siloxy-anchored monolayers with exposed amino, azido, bromo, or cyano groups

Abstract The creation of new, uniformly functionalized, surfaces has been achieved with mono layers bearing NH 2 , N 3 , Br, or CN functional groups.
Organometallic Electrochemistry: Origins, Development, and Future

The evolution of organotransition metal electrochemistry from its origin with ferrocene to its promise in future applications is presented. Examples are given of key findings on the relationships of electron transfer to molecular structures and to the reactions of organotransition metal complexes.
Hydrogen absorption-desorption kinetics of MmNi5 and related compounds

Abstract A study was made to determine the effects of aluminum and iron substitution on the reaction kinetics of MmNi 5 ( Mm = mischmetal). Each sample used in this study i.e. MmNi 5 , MmNi 4.5 A1 0.5 and MmNi 4.85 Fe 0.15 , was mixed with a heat buffer so that nearly isothermal conditions could be maintained. Experiments were also designed so that the ratio of the equilibrium plateau pressure to the opposing pressure was the same for each sample. This was done to ensure that the thermodynamic driving force acting on each sample was the same. In addition, a sufficiently large number of absorption-desorption cycles were initially done on each sample for reproducible results to be obtained. The relative reaction rates among the various samples studied were found to change with the temperatures and pressure ratios that were chosen. Thus it is very important that any comparison of the reaction kinetics of metal hydrides should also include information about the temperature intervals used and the activation energies of each sample, as well as quantitative expressions showing how the reaction rates change with the imposed pressure ratio. At 25 °C and a pressure ratio of 2, reaction rates were found to be in the following order: MmNi 5 > MmNi 4.5 Al 0.5 ≈ LaNi 5 > MmNi 4.85 Fe 0.15 Thus it was concluded that aluminum and iron substitution has a deleterious effect on the reaction kinetics of MmNi 5 hydride. Of the materials studied, MmNi 4.5 Al 0.5 seems to be the most practical material for hydrogen storage. This is because it has thermodynamic and kinetic properties similar to those of LaNi 5 but at a cheaper price.
A Chandra ACIS Study of 30 Doradus. II. X-Ray Point Sources in the Massive Star Cluster R136 and Beyond

We have studied the X-ray point-source population of the 30?Doradus (30 Dor) star-forming complex in the Large Magellanic Cloud using high spatial resolution X-ray images and spatially resolved spectra obtained with the Advanced CCD Imaging Spectrometer (ACIS) on board the Chandra X-Ray Observatory. Here we describe the X-ray sources in a 17' ? 17' field centered on R136, the massive star cluster at the center of the main 30?Dor nebula. We detect 20 of the 32 Wolf-Rayet stars in the ACIS field. The cluster R136 is resolved at the subarcsecond level into almost 100 X-ray sources, including many typical O3-O5 stars, as well as a few bright X-ray sources previously reported. Over 2 orders of magnitude of scatter in LX is seen among R136 O stars, suggesting that X-ray emission in the most massive stars depends critically on the details of wind properties and the binarity of each system, rather than reflecting the widely reported characteristic value LX/Lbol 10-7. Such a canonical ratio may exist for single massive stars in R136, but our data are too shallow to confirm this relationship. Through this and future X-ray studies of 30?Dor, the complete life cycle of a massive stellar cluster can be revealed.
Ice Mineralogy across and into the Surfaces of Pluto, Triton, and Eris

We present three near-infrared spectra of Pluto taken with the Infrared Telescope Facility and SpeX, an optical spectrum of Triton taken with the MMT and the Red Channel Spectrograph, and previously published spectra of Pluto, Triton, and Eris. We combine these observations with a two-phase Hapke model and gain insight into the ice mineralogy on Pluto, Triton, and Eris. Specifically, we measure the methane-nitrogen mixing ratio across and into the surfaces of these icy dwarf planets. In addition, we present a laboratory experiment that demonstrates it is essential to model methane bands in spectra of icy dwarf planets with two methane phases—one highly diluted by nitrogen and the other rich in methane. For Pluto, we find bulk, hemisphere-averaged, methane abundances of 9.1% ± 0.5%, 7.1% ± 0.4%, and 8.2% ± 0.3% for sub-Earth longitudes of 10°, 125°, and 257°. Application of the Wilcoxon rank sum test to our measurements finds these small differences are statistically significant. For Triton, we find bulk, hemisphere-averaged, methane abundances of 5.0% ± 0.1% and 5.3% ± 0.4% for sub-Earth longitudes of 138° and 314°. Application of the Wilcoxon rank sum test to our measurements finds the differences are not statistically significant. For Eris, we find a bulk, hemisphere-averaged, methane abundance of 10% ± 2%. Pluto, Triton, and Eris do not exhibit a trend in methane-nitrogen mixing ratio with depth into their surfaces over the few centimeter range probed by these observations. This result is contrary to the expectation that since visible light penetrates deeper into a nitrogen-rich surface than the depths from which thermal emission emerges, net radiative heating at depth would drive preferential sublimation of nitrogen leading to an increase in the methane abundance with depth.
Benjamin Franklin and His Gods

Against the religious backdrop of pre- and postcolonial America stands the towering figure - and mind - of Benjamin Franklin. A Renaissance man in a Revolutionary time, Franklin had interests and knowledge not only in religion but in literature, philosophy, politics, publishing, history, and scientific inquiry, among many other disciplines. Kerry S. Walters examines Franklin's search for the Divine using a similar, multifaceted approach - and in so doing has created the first extended treatment of Franklin's religious thought in thirty years. Walters brings the same intellectual range and depth to the understanding of Franklin's beliefs that Franklin brought to his own quest. What emerges from this pilgrimage into the soul of one of America's greatest figures is a very human Benjamin Franklin who grew with the accumulation of knowledge to arrive at a 'theistic perspectivism', which provided him with a philosophical explanation for the diversity of religious faiths - and a justification for the liberty of conscience he advocated throughout his life. "Benjamin Franklin and His Gods" is an original and beautifully challenging spiritual and intellectual biography. It is destined to be a classic.
Evaluation of GPS Ionospheric Time-Delay Model

For single-frequency global positioning system (GPS) users,uncompensated ionospheric GPS-signal time delay is the largestsource of range-measurement error, contributing as much as 100 m.To improve performance for these users, a numeric model of theionospheric range error was incorporated into the GPS system. Thispaper presents an assessment of that model in which actualionospheric time-delay values as measured by GPS dual-frequencyreceivers were compared with model values computed at the sametime points. Comparison was made over a broad range of conditionswith dependency of model accuracy on several of the modelparameters. It appears that the model leads to an overall reductionin rms range measurement error of 60 percent.
The geometry of differential privacy: the sparse and approximate cases

We study trade-offs between accuracy and privacy in the context of linear queries over histograms. This is a rich class of queries that includes contingency tables and range queries and has been the focus of a long line of work. For a given set of d linear queries over a database x ∈ RN, we seek to find the differentially private mechanism that has the minimum mean squared error. For pure differential privacy, [5, 32] give an O(log2 d) approximation to the optimal mechanism. Our first contribution is to give an efficient O(log2 d) approximation guarantee for the case of (e,δ)-differential privacy. Our mechanism adds carefully chosen correlated Gaussian noise to the answers. We prove its approximation guarantee relative to the hereditary discrepancy lower bound of [44], using tools from convex geometry. We next consider the sparse case when the number of queries exceeds the number of individuals in the database, i.e. when d > n Δ |x|1. The lower bounds used in the previous approximation algorithm no longer apply --- in fact better mechanisms are known in this setting [7, 27, 28, 31, 49]. Our second main contribution is to give an efficient (e,δ)-differentially private mechanism that, for any given query set A and an upper bound n on |x|1, has mean squared error within polylog(d,N) of the optimal for A and n. This approximation is achieved by coupling the Gaussian noise addition approach with linear regression over the l1 ball. Additionally, we show a similar polylogarithmic approximation guarantee for the optimal e-differentially private mechanism in this sparse setting. Our work also shows that for arbitrary counting queries, i.e. A with entries in {0,1}, there is an e-differentially private mechanism with expected error ~O(√n) per query, improving on the ~O(n2/3) bound of [7] and matching the lower bound implied by [15] up to logarithmic factors.The connection between the hereditary discrepancy and the privacy mechanism enables us to derive the first polylogarithmic approximation to the hereditary discrepancy of a matrix A.
Evaluating Potential for Data Assimilation in a Flux-transport Dynamo Model by Assessing Sensitivity and Response to Meridional Flow Variation

We estimate here a flux-transport dynamo model's response time to changes in meridional flow speed. Time variation in meridional flow primarily determines the shape of a cycle in this class of dynamo models. In order to simultaneously predict the shape, amplitude, and timing of a solar cycle by implementing an ensemble Kalman filter in the framework of Data Assimilation Research Testbed, it is important to know the model's sensitivity to flow variation. Guided by observations, we consider a smooth increase or decrease in meridional flow speed for a specified time (a few months to a few years), after which the flow speed comes back to the steady speed, and implement that time-varying meridional flow at different phases of solar cycle. We find that the model's response time to change in flow speed peaks at four to six months if the flow change lasts for one year. The longer the changed flow lasts, the longer the model takes to respond. Magnetic diffusivity has no influence in the model's response to flow variation as long as the dynamo operates in the advection-dominated regime. Experiments with more complex flow variations indicate that the shape and amplitude of flow perturbation have no influence in the estimate of the model's response time.
Exchange Reactions of Substituted Benzaldehyde Hydrazones

Hydrazones IV, derived from substituted benzaldehydes and N-aminophthalimide, experience an exchange reaction with one equivalent of 2,4-dinitrophenylhydrazine under conditions free of added mineral acid to cleanly and irreversibly produce the related 2,4-dinitrophenylhydrazones V in good yields. Although literature melting points for compounds V may vary from one reference to another, the infrared spectra (v (mull), cm−1; IV: 1770, 1710; V: 3280, 1615, 1580, 1510) of starting materials and products in the exchange process are strikingly different and permit ready characterization.
Sell Discipline and Institutional Money Management

There has been next to no study in the financial literature of sell decisions. An institutional money management database covering more than 7,000 investment portfolios now facilitates examination of different sell discipline criteria with respect to risk-adjusted returns and downside risk. The evidence indicates that portfolio performance is strongly related to the choice of the sell discipline criterion, even correcting for the potential effects of investment style changes over the period investigated. In rising markets, institutional money managers are likely to benefit from using less restrictive sell discipline criteria, while in declining markets they might benefit from a more restrictive sell discipline criterion. Market conditions, that is, strongly influence the effectiveness of the various sell discipline criteria.
Grain Growth and Global Structure of the Protoplanetary Disk Associated with the Mature Classical T Tauri Star, PDS 66

We present Australia Telescope Compact Array interferometric observations of the old (13 Myr), nearby (86 pc) classical T Tauri star (cTTS), PDS 66. Unresolved 3 and 12 mm continuum emission is detected toward PDS 66, and upper limits are derived for the 3 and 6 cm flux densities. The millimeter-wave data show a spectral slope flatter than that expected for interstellar medium-sized dust particles, which is evidence of grain growth. We also present HST/NICMOS 1.1 μm point-spread-function-subtracted coronagraphic imaging observations of the circumstellar environment of PDS 66. The Hubble Space Telescope observations reveal a bilaterally symmetric circumstellar region of dust scattering ~0.32% of the central starlight, declining in surface brightness as r ^(–4.53). The light-scattering disk of material is inclined 32° ± 5° from a face-on viewing geometry, and extends to a radius of 170 AU. These data are combined with published optical and longer wavelength observations to make qualitative comparisons between the median Taurus and PDS 66 spectral energy distributions. By comparing the near-infrared emission to a simple model, we determine that the location of the inner disk radius is consistent with the dust sublimation radius (~1400 K at 0.1 AU). We place constraints on the total disk mass using a flat-disk model and find that it is probably too low to form gas giant planets according to current models. Despite the fact that PDS 66 is much older than a typical cTTS (≤5 Myr), its physical properties are not much different.
Total synthesis of the potent proteasome inhibitor epoxomicin: a useful tool for understanding proteasome biology.

Epoxomicin (1), a peptide alpha',beta'-epoxyketone isolated from the actinomycete strain No.Q996-17, possesses potent in vivo anti-tumor and anti-inflammatory activities. In this paper, we report the first syntheses of epoxomicin, [3H]-epoxomicin, and a biotinylated epoxomicin analog as well as the absolute configuration of the epoxide stereocenter. The natural product and derivatives have permitted the first identification of the proteasome as the specific cellular target of epoxomicin.
Oxidation of α-methylbenzyl alcohols by dimethyldioxirane

Abstract Dimethyldioxirane converts p -substituted α-methylbenzyl alcohols to the corresponding acetophenones in excellent yield with α-hydroxyacetophenones as the minor products; the oxidation shows a ϱ of −1.57, PKIE of 3.55, KIE of 1.09 for OD and activation parameters with a large, negative ΔS ‡ term.
Interpretation of the anti-tail of comet Kohoutek as a particle flow phenomenon

The appearance of a 'sunward' spike, opposite in apparent orientation to the normal Type-II tail in Comet Kohoutek is interpreted as evidence for large particles ejected near perihelion. It is shown that the shape and orientation can be satisfactorily explained in this manner, after consideration of the increased mass flow at decreasing heliocentric distance. The apparent length of the spike can be a measure of the particle size and density, and a value of about 0.004 g/sq cm for the product of particle size and density fits the Skylab observations.
Quasi-random maximum simulated likelihood estimation of the mixed multinomial logit model

This paper proposes the use of a quasi-random sequence for the estimation of the mixed multinomial logit model. The mixed multinomial structure is a flexible discrete choice formulation which accommodates general patterns of competitiveness as well as heterogeneity across individuals in sensitivity to exogenous variables. The estimation of this model has been achieved in the past using the pseudo-random maximum simulated likelihood method that evaluates the multi-dimensional integrals in the log-likelihood function by computing the integrand at a sequence of pseudo-random points and taking the average of the resulting integrand values. We suggest and implement an alternative quasi-random maximum simulated likelihood method which uses cleverly crafted non-random but more uniformly distributed sequences in place of the pseudo-random points in the estimation of the mixed logit model. Numerical experiments, in the context of intercity travel mode choice, indicate that the quasi-random method provides considerably better accuracy with much fewer draws and computational time than does the pseudo-random method. This result has the potential to dramatically influence the use of the mixed logit model in practice; specifically, given the flexibility of the mixed logit model, the use of the quasi-random estimation method should facilitate the application of behaviorally rich structures in discrete choice modeling.
Combined effects of mechanical and acoustic vibrations on fluidization of cohesive powders

Abstract Bubbling fluidized bed experiments were performed on powders ranging in size from 0.012 to 15 μm, with room temperature air as the fluidizing gas. Powders this fine are cohesive in nature and typically form clusters of particles, which can interfere with the fluidization process and, in some cases, result in channeling and spouting, instead of bubbling. Previous studies in our laboratory explored the use of high intensity acoustic vibrations to disrupt the interparticle forces and decrease the superficial gas velocities needed to achieve minimum fluidization. The present paper deals with the simultaneous use of acoustics and horizontal mechanical vibrations to achieve fluidization. Experiments were run with the bed equipped with a loudspeaker at the top of the freeboard and a motor-driven mechanism to impart horizontal vibrations to the fluidized bed column. Results are presented on the effects of these two types of vibrations on minimum fluidization.
Design and synthesis of a novel three-hindered quadrant bisphosphine ligand and its application in asymmetric hydrogenation

A novel three hindered quadrant bisphosphine ligand has been synthesized. The ligand shows excellent enantioselectivities and reactivities for rhodium-catalyzed hydrogenations of various functionalized olefins.
Estimating the energy source and reflectivity by seismic inversion

Data produced by a reproducible source contains redundant information which allows seismic inversion to simultaneously determine the high-frequency fluctuation in the P-wave velocity (or reflectivity) as well as the input energy source. The seismogram model is the plane-wave convolutional model derived from the constant density, variable sound velocity acoustic wave equation. The first step is to analyse this linearized model when the background velocity is constant. Then perturbations in the seismic data stably determine corresponding perturbations in the source and reflectivity. The stability of this determination improves as the slowness aperture over which the data is defined increases. Further, the normal operator for the convolutional seismogram model is continuous with respect to velocity. Thus the stability result for constant background velocities may be extended to more realistic background velocity models which vary slowly and smoothly with depth. The theory above is illustrated with four synthetic numerical examples derived from marine data. The examples indicate that for a wide slowness aperture, inversion is very effective in establishing the true shape of the reflectivity and the shape and location of the compactly supported energy source. As this aperture window narrows, the corresponding inversion-estimated model still describes the data quite accurately, but the inversion is not able to recover the original two distinct parameters.
An evaluation of the stability of image-quality parameters of Varian on-board imaging (OBI) and EPID imaging systems

Quality assurance (QA) of the image quality for image-guided localization systems is crucial to ensure accurate visualization and localization of regions of interest within the patient. In this study, the temporal stability of selected image parameters was assessed and evaluated for kV CBCT mode, planar radiographic kV, and MV modes. The motivation of the study was to better characterize the temporal variability in specific image-quality parameters. The CATPHAN, QckV-1, and QC-3 phantoms were used to evaluate the image-quality parameters of the imaging systems on a Varian Novalis Tx linear accelerator. The planar radiographic images were analyzed in PIPSpro with high-contrast spatial resolution (f30, f40, f50 lp/mm) being recorded. For OBI kV CBCT, high-quality head full-fan acquisition and pelvis half-fan acquisition modes were evaluated for uniformity, noise, spatial resolution, HU constancy, and geometric distortion. Dose and X-ray energy for the OBI were recorded using the Unfors RaySafe Xi system with the R/F High Detector for kV planar radiographic and the CT detector for kV CBCT. Dose for the MV EPID was recorded using a PTW975 Semiflex ion chamber, PTW UNIDOS electrometer, and CNMC Plastic Water. For each image-quality parameter, values were normalized to the mean, and the normalized standard deviations were recorded to evaluate the parameter’s temporal variability. For planar radiographic modes, the normalized standard deviations of the spatial resolution (f30, f40, & f50) were 0.015, 0.008, 0.004 lp/mm and 0.006, 0.009, 0.018 lp/mm for the kV and MV, respectively. The normalized standard deviation of dose for kV and MV were 0.010 mGy and 0.005mGy, respectively. The standard deviations for full- and half-fan kV CBCT modes were averaged together. The following normalized standard deviations for each kV CBCT parameter were: 0.075 HU (uniformity), 0.071 HU (noise), 0.006mm (AP-geometric distortion), 0.005 mm (LAT-geometric distortion), 0.058mm (slice thickness), 0.124 (f50), 0.031 (HU constancy – Lung), 0.063 (HU constancy– Water), 0.020 (HU constancy – Bone), 0.006 mGy (Dose – Center), 0.004 mGy (Dose –Periphery). Using control chart analysis, institutional QA tolerances were reported as warning and action thresholds based on 1σ and 2σ thresholds. A study was performed to characterize the stability of image-quality parameters recommended by AAPM Task Group-142 for the Varian OBI and EPID imaging systems. Both imaging systems show consistent imaging and dosimetric properties over the evaluated time frame.
Entrepreneurship, Innovation and Industrial Development: Geography and the Creative Field Revisited

Creative destruction is a central element of the competitive dynamic of capitalism. This phenomenon assumes concrete form in relation to specific geographical and historical conditions. One such set of conditions is investigated here under the rubric of the creative field, i.e. the locationally-differentiated web of production activities and associated social relationships that shapes patterns of entrepreneurship and innovation in the new economy. The creative field operates at many different levels of scale, but I argue that the urban and regional scale is of special interest and significance. Accordingly, I go on to describe how the creative field functions as a site of (a) entrepreneurial behavior and new firm formation, (b) technical and organizational change, and (c) the symbolic elaboration and re-elaboration of cultural products. All of these activities are deeply structured by relations of spatial-cum-organizational proximity and separation in the system of production. The creative field, however, is far from being a fully self-organizing entity, and it is susceptible to various kinds of breakdowns and distortions. Several policy issues raised by these problems are examined. The paper ends by addressing the question as to whether industrial agglomeration is an effect of producers’ search for creative synergies, or whether such synergies are themselves simply a contingent outcome of agglomeration.
Using perceptual inference networks to manage vision processes

We provide a probabilistic framework, based on Perceptual Inference Networks, for the management of computational resources such as special purpose modules, feature detectors, and highly domain dependent algorithms. Since these resources tend to be computationally expensive and have limited applicability, judicious management is warranted. The resources are used to build a comprehensive description of the scene. Resources are selected in an information theoretic framework with the maximization of information gain per unit of computation as the optimality criterion. The viability of the algorithm is demonstrated in perceptual organization tasks.
E-(hydroxyimino)(hydroxymethoxyphosphinyl)acetic acid: Synthesis and pH-dependent fragmentation

Abstract In contrast to both its parent “troika” acid ( E - 1 , a phosphorylating agent at pH 7 and 25 °C) and its C-methyl isomer ( E - 2 , which is stable at both acidic and neutral pH), ( E )-(hydroxyimino)(hydroxymethoxyphosphinyl)acetic acid E - 3 was unreactive at pH 7 and 25 °C but at pH 1.5 fragmented to methyl phosphate 10 (15%) and methyl phosphorocyanidate 11 (85%). The minor product is consistent with solvent phosphorylalion, the reaction exclusively observed with E - 1 . The non-phosphorylating fragmentation pathway is proposed to involve a preliminary E → Z isomerizalion of 3 prior to C α -C β cleavage. Dual fragmentation pathways were also detected ( 31 P NMR) when the DCHA + salt of E - 3 ( E - 9 ) was heated in acetonitrile or EtOH; in addition to phosphorylation products (16–19%), 11 was formed (81–84%). Reaction of E - 9 in refluxing EtOH: t -BuOH (1:1) showed low stereoselectivity in product formation (~3:1 ethyl methyl phosphate: t -butyl methyl phosphate), supporting a dissociative phosphorylation process.
Propagators for massive symmetric tensor and p-forms in AdS d+1

We construct propagators in euclidean AdSd+1 space-time for massive p-forms and massive symmetric tensors.
Sudden commencement associated discontinuities in the interplanetary magnetic field observed by IMP 3

The magnetic field measurements made by the magnetic field experiment on the IMP 3 (Explorer 28) spacecraft have been examined at the time of geomagnetic s.s.c. events. Thirty-six such events occurred while IMP 3 was in the interplanetary medium during 1965, 1966 and 1967 and have been analysed. Of these events 8 must have been tangential discontinuities, 2 are either tangential discontinuities or rotational discontinuities and 26 are possible shock waves. (Two of these 26 events have been shown by other authors to be shocks.) These 26 possible shocks have similar magnetic signatures: an increase of 20 % or more in the magnetic field magnitude and a relatively small (always less than 90°) change in direction. The larger s.s.c. events were more likely to be caused by possible shocks while the smaller events were often associated with tangential discontinuities. The orientation of the discontinuity surfaces of the 26 possible shocks shows a preference to be aligned somewhere between a direction perpendicular to the sun-earth line and a direction tangent to the local spiral angle of the magnetic field. It was possible to associate solar flares with 14 of the 26 possible shock events. Of these 14, a reliable orientation was deduced for 8 events. By considering the orientation of these 8 events in relation to the position of the parent flares on the solar disk it is suggested that a typical shock front propagating out from the sun has a radius of curvature less than but of the order of 1 AU.
Electrodeposition of YBaCuO and ErBaCuO superconductor precursor films

Abstract Precursor thin films of YBaCuO and ErBaCuO superconductor were produced by pulse plating from the dissolved nitrate salts of yttrium, barium, copper and erbium, barium, copper in dimethylformamide. The films were produced on zirconium as well as silvercoated SrTiO3 and CaTiO3. The electrodeposited films were heat treated in flowing O2. Film composition was determined by energy-dispersive X-ray analysis. Critical temperature transitions were determined by magnetic as well as resistivity measurements. Onset critical temperatures were measured up to 93 and 80 K for YBaCuO and ErBaCuO respectively. In resistivity measurements of YBaCuO on CaTiOa, a small step drop at approximately 240 K was observed. This drop in resistivity disappeared after one thermal cycle. Similar drops in resistivity above 200 K have been observed by other authors. Compared with potentiostatic and galvanostatic techniques, the use of pulse plating enhances nucleation and growth and results in uniform and homogeneous films.
Hadronic parity violation in pionless effective field theory

We present results for two-body observables that are sensitive to the parity-violating component of nucleon-nucleon interactions. These interactions are studied using an effective field theory in which the only dynamic degrees of freedom are nucleon fields. The observables we study are cross-section asymmetries in nucleon-nucleon scattering and asymmetries and induced polarizations in the process np→dγ.
Mare Basalt Petrogenesis

Melting experiments in vacuum at Fe-saturation for high-Ti lunar basalt compositions 70215 and 15318 Red Glass, and low-Ti basalt composition 15555-15016, have defined equilibrium crystallization sequences and the liquid lines of descent, and show that much of the chemical variety in the samples is due to near-surface fractionation processes. The various groups within the high-Ti suite, however, cannot be interrelated by such processes, nor can the high-Ti suite be a near-surface derivative of a low-Ti parent magma.
Gas turbine cogeneration principles and practice

During the decade of the 1960s, industrial users recognized the gas turbine as a reliable prime mover for base load process applications. Gas turbine cogeneration systems were installed in various industries, including chemical, petroleum refining, pulp and paper, and metals. Typically, the size of the cogeneration system considered, and thus the gas turbine size, was governed by the internal heat and power demands of the specific plant. More recently, worldwide concern with regard to the cost and efficient use of energy is providing continuing opportunities for gas turbine cogeneration systems. In some locations, legislation is being enacted to encourage the development of cogeneration to the benefit of the public. This legislation can increase the number of alternative methods in which a cogeneration system can be developed. This paper will briefly review cogeneration principles applicable to the development of gas turbine energy supply systems. The wide range of conditions that can be satisfied using gas turbine cogeneration systems will be introduced. Brief discussions of recent installations are presented, illustrating the actual applications of some of these concepts.
Photofluid instabilities of hot stellar envelopes

Abstract Beginning from a relatively simple set of dynamical equations for a fluid permeated by a radiative field strong enough to produce significant forces, we find the structure of plane-parallel equilibria and study their stability to small acoustic disturbances. In doing this, we neglect viscous effects and complications of nongrayness. We find that acoustic instabilities occur over a wide range of conditions below the Eddington limit. This result is in line with findings reported 20 years ago but it contradicts a more recent report of the absence of instabilities. We briefly attempt to identify the causes of the discrepancies and then close with allusions to the possible astrophysical interest of such instabilities.
Burn out in user services

The term "burn out" is frequently used to describe a person's fatigue or tire of a particular job or task. More often than not, it is associated with the helping professions and other jobs where people help other people. It is common to hear someone say that they are "burned out on the job," or "burned out on people," or just plain "burned out." One of the themes of the 8th User Services Conference held in 1980 in Morgantown, West Virginia, was the topic of the effects and treatment of burn out in user services personnel. Papers presented by Dr. James F. Carruth of West Virginia University and Janice A. Bartleson of Southern Illinois University were helpful in defining and coping with the problems of job fatigue in user services. In 1984, we have organized this panel discussion to reinspect the topic, especially with regard to the numerous changes that have taken place in our computing environments and the ways in which we help our users. To anyone working in user services, it should be obvious that the spreading out of computing services, in both quality and quantity, will continue to have dramatic impacts on the people who are designated to "help the users help themselves."
Transient temperature distribution for fully developed laminar flow in a tube

Abstract The time dependent temperature distribution is obtained for a fluid flowing in a tube. The flow is considered to be laminar and fully developed and the fluid properties are assumed to be constant. Several combinations of boundary conditions are considered and closed form solutions for the case of uniform flow are obtained. For the case of parabolic velocity distribution the mathematical dificulties are detailed.
Percolation Analysis of a Wiener Reconstruction of the IRAS 1.2 Jy Redshift Catalog

We present percolation analyses of Wiener reconstructions of the IRAS 1.2 Jy redshift survey. There are 10 reconstructions of galaxy density fields in real space spanning the range β = 0.1-1.0, where β = Ω0.6/b, Ω is the present dimensionless density, and b is the bias factor. Our method uses the growth of the largest cluster statistic to characterize the topology of a density field, where Gaussian randomized versions of the reconstructions are used as standards for analysis. For the reconstruction volume of radius R ≈ 100 h-1 Mpc, percolation analysis reveals a slight "meatball" topology for the real space, galaxy distribution of the IRAS survey.
Complete solution for M(atrix) theory at two loops

The complete result for the effective potential for two graviton exchange at two loops in M(atrix) theory can be expressed in terms of a generalized hypergeometric function.
Glassy dynamics of driven elastic manifolds

Abstract We study the low-temperature dynamics of an elastic manifold driven through a random medium. For driving forces well below the zero-temperature depinning force, the manifold advances via thermally activated hops over the energy barriers separating favorable metastable states. We develop a scaling theory of the thermally activated dynamics (creep) and find a nonlinear glassy response for the driven manifold, ν ∼ exp(−const × F−μ). We consider an exactly solvable one-dimensional model for random driven dynamics which exhibits a creep-like velocity-force characteristic. We discuss a microscopic mechanism for the creep motion and show that the distribution of waiting times for the hopping processes scales as a power-law. This power-law distribution naturally yields an exponential response for the creep of the manifold.
Selective formation of 1,5-substituted sulfonyl triazoles using acetylides and sulfonyl azides.

The reaction of acetylides with sulfonyl azides was found to selectively form 1,5-substituted sulfonyl triazoles. This reaction thus provides access to the regioisomeric product as compared to the popular copper-catalyzed azide–alkyne cycloaddition. The reaction is efficient and selective with a variety of alkyne sources and sulfonyl azides and can incorporate an additional electrophile to yield 1,4,5-trisubstituted sulfonyl triazoles.
D-brane actions with local kappa symmetry☆

Abstract We formulate world-volume actions that describe the dynamics of Dirichlet p -branes in a flat 10d background. The fields in these theories consist of the 10d superspace coordinates ( X m , θ) and an abelian world-volume gauge field A μ . The global symmetries are given by the N = 2A or N = 2B super-Poincare group, according to whether p is even or odd. The local symmetries in the ( p + 1)-dimensional world volume are general coordinate invariance and a fermionic kappa symmetry.
The stability of vacua in two-dimensional gauge theory

We discuss the stability of vacua in two-dimensional gauge theory for any simple, simply connected gauge group. Making use of the representation of a vacuum in terms of a Wilson line at infinity, we determine which vacua are stable against pair production of heavy matter in the adjoint of the gauge group. By calculating correlators of Wilson loops, we reduce the problem to a problem in representation theory of Lie groups, that we solve in full generality.
Microwave Resonance Relations in Anisotropic Single-Crystal Ferrites

The ferromagnetic resonance relations in magnetically anisotropic single-crystal ferrites have been re-examined. Detailed analyses are presented for spherical ferrite specimens possessing first order anisotropy. Generalized nomograms are presented which relate the microwave resonance frequency to the static magnetic field $H$, the anisotropy parameter $\frac{K}{M}$, and the static field orientation angle. These curves are derived for both negative and positive anisotropy specimens with H lying in a (110) crystal plane.Below magnetic saturation a simple multi-domain structure is suggested by crystal geometry in which the domains are lamellar in form. The orientations of the magnetizations in these domains are assumed to be of two varieties which alternate in sequence. Equilibrium and resonance results are given for such a configuration when H is applied in the [110] direction. Two resonant frequencies are found for a given H, depending on whether the microwave field is perpendicular or parallel to H. For both positive and negative anisotropy crystals, nomograms are given relating the resonance frequencies to $H$, $\frac{K}{M}$, and $M$. The results depend sensitively on the magnetization $M$. The nature of the magnetization curve predicted from this structure is discussed.The angular variation of resonance field and the positions of the secondary resonances found in recent experiments by Tannenwald are in accord with theory.
Total syntheses of dalesconol A and B

A polycyclic collapse: Use of a carefully designed acyclic intermediate provided the means to execute a cascade-based construction which formed the entire core of the polyketide-derived dalesconols in a single flask. A number of additional and carefully controlled synthetic operations completed an expeditious synthesis of both of these highly bioactive natural products as well as structural congenors.
Use of catalyst pharmacophore models for screening of large combinatorial libraries.

Using a data set comprised of literature compounds and structure−activity data for cyclin dependent kinase 2, several pharmacophore hypotheses were generated using Catalyst and evaluated using several criteria. The two best were used in retrospective searches of 10 three-dimensional databases containing over 1 000 000 proprietary compounds. The results were then analyzed for the efficiency with which the hypotheses performed in the areas of compound prioritization, library prioritization, and library design. First as a test of their compound prioritization capabilities, the pharmacophore models were used to search combinatorial libraries that were known to contain CDK active compounds to see if the pharmacophore models could selectively choose the active compounds over the inactive compounds. Second as a test of their utility in library design again the pharmacophore models were used to search the active combinatorial libraries to see if the key synthons were over represented in the hits from the pharmaco...
Drivers and Barriers in Health IT Adoption: A Proposed Framework

Despite near (and rare) consensus that the adoption and diffusion of health information technology (health IT) will bolster outcomes for organizations, individuals, and the healthcare system as a whole, there has been surprisingly little consideration of the structures and processes within organizations that might drive the adoption and effective use of the technology. Management research provides a useful lens through which to analyze both the determinants of investment and the benefits that can ultimately be derived from these investments. This paper provides a conceptual framework for understanding health IT adoption. In doing so, this paper highlights specific organizational barriers or enablers at different stages of the adoption process – investment, implementation, and use – and at different levels of organizational decision-making – strategic, operational, and frontline. This framework will aid both policymakers and organizational actors as they make sense of the transition from paper-based to electronic systems.
Beta-Carotene in HIV Infection

beta-Carotene has been reported to have an immunostimulatory effect. Recent studies suggest that beta-carotene supplementation can increase CD4 counts in HIV-infected patients. Our double-blind, placebo-controlled clinical trial was designed to test the efficacy of beta-carotene in raising CD4 counts in HIV-infected patients. Twenty-one HIV-seropositive patients were randomized to receive either beta-carotene, 180 mg/day or placebo for 4 weeks, and then crossed over to receive the alternative treatment for the following 4 weeks. beta-Carotene resulted in a statistically significant increase in total WBC count (p = 0.01), % change in CD4 count (p = 0.02), and % change in CD4/CD8 ratios (p = 0.02) compared to placebo. The absolute CD4 count, absolute CD4/CD8 ratio, and total and B-lymphocytes all increased on carotene and fell during placebo, but these differences did not reach statistical significance. No toxicity was observed on either treatment. beta-Carotene appears to have an immunostimulatory effect in HIV-infected patients. Further studies are needed to demonstrate whether beta-carotene has a role as adjunct therapy in treatment of HIV-infected patients.
Government's response to Hurricane Katrina: A public choice analysis

We use public choice theory to explain the failure of FEMA and other governmental agencies to carry out effective disaster relief in the wake of Hurricane Katrina. The areas in which we focus are: (1) the tragedy of the anti-commons resulting from layered bureaucracy, (2) a type-two error policy bias causing over cautiousness in decision making, (3) the political manipulation of disaster declarations and relief aid to win votes, (4) the problem of acquiring timely and accurate preference revelations, (5) glory seeking by government officials, and (6) the shortsightedness effect causing a bias in governmental decision making.
Nanoparticles in the Atmosphere

The most continuous and intimate contact the average person has with nanoparticles is almost surely through the air, which is replete with them. Nanoparticles are being generated continuously and in large numbers by vehicles and industries in urban areas and by vegetation and sea spray in rural areas. Volcanoes are sporadic sources of huge numbers. Nanoparticles have large surface area to volume ratios and react rapidly in the atmosphere, commonly growing into particles large enough to interact with radiation and to have serious consequences for visibility and local, regional, and global climate. They also have potentially significant health effects.
Fitting direct interaction pieces into neutrino puzzles

Abstract We develop a framework and unified, compact notation to include neutrino direct interaction effects with neutrino oscillations for a wide class of low-energy, effective four-Fermi interactions. Modest flavor-violating interaction strengths can make significant changes in the boundaries in ΔM 2 ↔sin 2 2 θ and in tan 2 θ 13 ↔tan 2 θ 23 parameter space. We draw examples from the L − R symmetric and MSSM + R / models and find the recently reported decay-at-rest μ ↔ e transition probability can be described without oscillations in L − R symmetric models.
Density scaling and dynamic correlations in viscous liquids.

We use a recently proposed method (Berthier, L.; Biroli, G.; Bouchaud, J.P.; Cipelletti, L.; El Masri, D.; L’Hote, D.; Ladieu, F.; Pierno, M. Science 2005, 310, 1797) to obtain an approximation to the four-point dynamic correlation function from derivatives of the linear dielectric response function. For four liquids over a range of pressures, we find that the number of dynamically correlated molecules, Nc, depends essentially only on the magnitude of the relaxation time, τα, independently of temperature and pressure. This result is consistent with the invariance of the shape of the relaxation dispersion at constant τα and the density scaling property of the relaxation times, and implies that Nc also conforms to the same scaling behavior. For propylene carbonate and salol, Nc becomes constant with approach to the Arrhenius regime, consistent with the value of unity expected for intermolecularly noncooperative relaxation.
Application of a constrained-transfer-matrix method to metastability in the d = 2 Ising ferromagnet

Abstract Applying a numerical transfer-matrix formalism, we obtained complex-valued constrained free energies for the two-dimensional square-lattice nearest-neighbor Ising ferromagnet below its critical temperature and in an external magnetic field. In particular, we study the imaginary part of the constrained free-energy branch that corresponds to the metastable phase. Although droplets are not introduced explicitly, the metastable free energy is obtained in excellent agreement with field-theoretical droplet-model predictions. The finite-size scaling properties are different in the weak-field and intermediate-field regimes, and we identify the corresponding different critical-droplet shapes. For intermediate fields, we show that the surface free energy of the critical droplet is given by a Wuff construction with the equilibrium surface tension. We also find a prefactor exponent in complete agreement with the field-theoretical droplet model. Our results extend the region of validity for known results of this field-theoretical droplet model, and they indicate that this transfer-matrix approach provides a nonperturbative numerical continuation of the equilibrium free energy into the metastable phase.
Stereoselectivity and Regioselectivity in the Segment-Coupling Prins Cyclization

The scope of the segment-coupling Prins cyclization has been investigated. The method is outlined in Scheme 1 and involves esterification of a homoallylic alcohol (1), reductive acetylation to give the alpha-acetoxy ether (3), and cyclization on treatment with a Lewis acid to produce a tetrahydropyran (4). Alkene geometries dictate the product configurations, with E-alkenes leading to equatorial substituents and Z-alkenes leading to axial substituents (Table 1). Not unexpectedly, applying the method to allylic alcohols leads to fragmentation rather than a disfavored 5-endo-trig cyclization. Dienols in which one alkene is allylic and the other alkene is homoallylic cyclize efficiently and produce the tetrahydropyrans 49-54, Table 3. Dienols with two homoallylic alkenes cyclize with modest to high regioselectively, generating tetrahydropyrans 40-45, Table 2. The relative rates for cyclization decrease in the order of vinyl > Z-alkene > E-alkene > alkyne. The configurations of the products are consistent with cyclization via a chair conformation, Figure 1. The 2-oxonia Cope rearrangement may be a factor in the regioselectivity of diene cyclizations and in the erosion of stereoselectivity with Z-alkenes. This investigation establishes the stereoselectivity and regioselectivity for a number of synthetically useful segment-coupling Prins cyclizations.