cssi/SciSciGPT-SciSciNet huggingface dataset:
“Gleaners” and “Waste”: The Post-Issue/Advocacy Documentary

Abstract Issue/advocacy filmmaking has changed significantly in recent decades. Many modern documentary filmmakers have no problem placing themselves within their films, even when those films are not necessarily about them. A few filmmakers have gone even further, however, using the “issue” as merely a starting-off point, sometimes leaving it behind completely, a practice that has resulted in a new era, or at least a subgenre or trend, that might be called the “post-issue/advocacy” documentary. This new type of documentary is illustrated through a comparison of two recent films—Agnes Varda's The Gleaners and I and Lucy Walker's Waste Land.
Emission-Line Gas Kinematics in the Vicinity of the Supermassive Black Holes in Nearby Radio Galaxies*

We describe our characterization of the kinematics of the emission-line gas in the nuclear regions of a complete sample of 21 nearby radio galaxies. We obtained data using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. We show that the point-to-point variations are largest perpendicular to the disks and in nuclei where the organized motion is less pronounced, suggesting that motions are present from gas that has not settled into smooth rotation. We show that the velocity dispersion is not distributed as a function of inclination, and so likely arises from isotropic random motions in the gas. We find that the difference in mean velocities on either side of the nucleus does not vanish as the disks become face-on, suggesting there may be bulk motions of the gas disks. We show that the gas velocity dispersions are closely related to the stellar velocity dispersions, which has implications for black hole fueling and growth mechanisms. We show that significant motions digressing from a smooth thin disk configuration are ubiquitous, and even in those cases where the velocity profile of the emission-line gas appears smooth and uncomplicated there may be dynamical components of the system that are not explained by a thin Keplerian disk model, suggesting caution in the use of gas disk kinematics for the determination of black hole masses.
Determining the Physical Properties of the B Stars. I. Methodology and First Results

We describe a new approach to fitting the UV-to-optical spectra of B stars to model atmospheres and present initial results. Using a sample of lightly reddened stars, we demonstrate that the Kurucz model atmospheres can produce excellent fits to either combined low-dispersion IUE and optical photometry or HST FOS spectrophotometry, as long as the following conditions are fulfilled: (1) an extended grid of Kurucz models is employed; (2) the IUE NEWSIPS data are placed on the FOS absolute flux system using the Massa & Fitzpatrick transformation; (3) and all of the model parameters and the effects of interstellar extinction are solved for simultaneously. When these steps are taken, the temperatures, gravities, abundances, and microturbulence velocities of lightly reddened B0-A0 V stars are determined to high precision. We also demonstrate that the same procedure can be used to fit the energy distributions of stars that are reddened by any UV extinction curve that can be expressed by the Fitzpatrick & Massa parameterization scheme. We present an initial set of results and verify our approach through comparisons with angular diameter measurements and the parameters derived for an eclipsing B-star binary. We demonstrate that the metallicity derived from the ATLAS9 fits to main-sequence B stars is essentially the Fe abundance. We find that a near zero microturbulence velocity provides the best fit to all but the hottest or most luminous stars (where it may become a surrogate for atmospheric expansion) and that the use of white dwarfs to calibrate UV spectrophotometry is valid.
A hard X-ray source in the nearest molecular cloud

The previous unidentified hard X-ray source H 0253 + 193 is coincident with Lynds 1457, a dark nebula at high galactic latitude (l = 159 deg, b = -34 deg). The Einstein IPC position coincides with the peak in the CO map obtained by Hobbs, Blitz, and Magnani (1986). Using interstellar Na I absorption, these authors determined a distance to the cloud of 65 pc, making this the nearest known molecular cloud. The X-ray source can be explained as an embedded T Tauri star with a 2-10 keV luminosity of 1 x 10 to the 31st erg/s.
Eddington-limited X-Ray Bursts as Distance Indicators. I. Systematic Trends and Spherical Symmetry in Bursts from 4U 1728–34

We investigate the limitations of thermonuclear X-ray bursts as a distance indicator for the weakly magnetized accreting neutron star 4U 1728-34. We measured the unabsorbed peak flux of 81 bursts in public data from the Rossi X-Ray Timing Explorer (RXTE). The distribution of peak fluxes was bimodal: 66 bursts exhibited photospheric radius expansion (presumably reaching the local Eddington limit) and were distributed about a mean bolometric flux of 9.2 × 10-8 ergs cm-2 s-1, while the remaining (non-radius expansion) bursts reached 4.5 × 10-8 ergs cm-2 s-1, on average. The peak fluxes of the radius expansion bursts were not constant, exhibiting a standard deviation of 9.4% and a total variation of 46%. These bursts showed significant correlations between their peak flux and the X-ray colors of the persistent emission immediately prior to the burst. We also found evidence for quasi-periodic variation of the peak fluxes of radius expansion bursts, with a timescale of 40 days. The persistent flux observed with RXTE/ASM over 5.8 yr exhibited quasi-periodic variability on a similar timescale. We suggest that these variations may have a common origin in reflection from a warped accretion disk. Once the systematic variation of the peak burst fluxes is subtracted, the residual scatter is only 3%, roughly consistent with the measurement uncertainties. The narrowness of this distribution strongly suggests that (1) the radiation from the neutron star atmosphere during radius expansion episodes is nearly spherically symmetric and (2) the radius expansion bursts reach a common peak flux that may be interpreted as a standard candle intensity. Adopting the minimum peak flux for the radius expansion bursts as the Eddington flux limit, we derive a distance for the source of 4.4-4.8 kpc (assuming RNS = 10 km), with the uncertainty arising from the probable range of the neutron star mass MNS = 1.4-2 M☉.
Present Evidence for Intermediate Mass Black Holes in ULXs and Future Prospects

In a number of the most luminous ULXs (those with L X ∼ 1040 erg s−1) in nearby galaxies, observations with XMM-Newton and Chandra are revealing evidence which suggests that these ULXs may harbor intermediate-mass black holes (IMBHs). The detection of accretion disk spectral components with temperatures 5–10 times lower than the temperatures observed in stellar-mass black hole binaries near to their Eddington limit may be particularly compelling evidence for IMBH primaries, since T α M−1/4 for disks around black holes. In some sources, X-ray timing diagnostics also hint at IMBHs. Evidence for IMBHs in a subset of the most luminous ULXs, a discussion of the robustness of this evidence and alternatives to the IMBH interpretation, and prospects for better determining the nature of these sources in the future, are presented in this work.
A Numerical Investigation of New England Coastal Frontogenesis

Abstract A three-dimensional, primitive equation, boundary-layer model is used to investigate wintertime mesoscale frontogenesis along the New England coast. Some features included in the model are a terrain-following coordinate system to study the effects of irregular terrain, a stable beating scheme to allow for the release of latent heat and to estimate precipitation, and an upper boundary condition on pressure which permits interaction with the synoptic-scale circulation. Numerical experiments with the model have verified the hypothesis that coastal fronts form when a cold anticyclone is located just to the north or northeast of New England, and a wave disturbance at 700 mb approaches the northeast from the midwest United States. Polar continental air flowing southwestward around the eastern side of the anticyclone is modified rapidly by sensible and latent heat transfer from the relatively warm Atlantic Ocean. As the 700 mb trough approaches the northeast, surface winds over the ocean veer from north...
Politics In A Dynamic View Of Land-Use Regulations: Of Interest Groups And Homevoters

The nature of land-use regulation differs by type of jurisdiction. Regulatory politics at the local level is the major source of the dynamic consistency problem. Courts are reluctant to enforce the regulatory commitments of previous officials at all levels of government, but the alternative political and reputation constraints on official promise-keeping are most problematic at the local level. Local majoritarianism presents the greatest challenge to attempts to improve the dynamic efficiency of land-use regulation.
Stabilization of the balance of payments in a small, planned economy, with an application to ethiopia

Abstract We construct a macroeconomic model of a planned economy and derive a currency basket that will stabilize the current account. The exchange rate is incorporated in a monetary system so as to derive consistent money and price targets. If the planners have access to foreign loans, they may target a negative current account. The model is estimated for Ethiopia. Having derived weights for the currency basket corresponding to 1980, a simulation is carried out in which macroeconomic targets for 1980 are derived, based on past information.
All-Atom Ab Initio Folding of a Diverse Set of Proteins

Natural proteins fold to a unique, thermodynamically dominant state. Modeling of the folding process and prediction of the native fold of proteins are two major unsolved problems in biophysics. Here, we show successful all-atom ab initio folding of a representative diverse set of proteins by using a minimalist transferable-energy model that consists of two-body atom-atom interactions, hydrogen bonding, and a local sequence-energy term that models sequence-specific chain stiffness. Starting from a random coil, the native-like structure was observed during replica exchange Monte Carlo (REMC) simulation for most proteins regardless of their structural classes; the lowest energy structure was close to native-in the range of 2-6 A root-mean-square deviation (rmsd). Our results demonstrate that the successful folding of a protein chain to its native state is governed by only a few crucial energetic terms.
CsI and some new photocathodes

A discussion of the possible sources of discrepancies in the measurements of the quantum efficiency of CsI photocathodes is presented. We propose that the major causes for disagreements in QE are due to the QE dependence on the current density extracted from the photocathode, on the electric field, and on the temperature of the photocathode. Preliminary results on TMAE enhanced GaAs and Si, plus TMAE protected CsTe and SbCs photocathodes, operated in gas, are also presented.
Supercritical fluid extraction of polychlorinated dibenzo-p-dioxins from municipal incinerator fly ash

Supercritical fluids are finding acceptance as solvation media in environmental analytical chemistry. Most reported applications aof supercritical fluid extraction (SFE) deal with coupling of small volume extractors to Ugh resolution gas chromatography. These two techniques in tandem or off-line, may speed-up the analyses of contaminants. Perhaps the most difficult matrix is fly ash, formed during combustion of municipal garbage
Recognition memory deficits in a subpopulation of aged monkeys resemble the effects of medial temporal lobe damage.

Abstract The present study examined individual differences in recognition memory function in a group of Old World monkeys (Macaca mulatta). Four young (9–11 years) and 10 aged (22–33 years) monkeys were tested in the same delayed-nonmatching-to-sample (DNMS) recognition memory procedure that has been widely used to study the effects of experimental hippocampal lesions in young subjects. Animals were first trained to a 90% correct learning criterion in the DNMS task using a 10-second delay between the sample and recognition phase of each trial. The memory demands of the task were then increased by gradually extending the retention interval from 15 seconds to 10 minutes. Three of the aged monkeys performed as accurately as young subjects at all delays. The remaining aged monkeys performed well at the shortest delays (15 and 30 seconds), but progressively greater impairments emerged across delays of 60 seconds, 2 minutes, and 10 minutes. These results suggest that recognition memory is only compromised in a subpopulation of aged monkeys. Moreover, aged monkeys that are impaired in the DNMS task exhibit the same delay-dependent pattern of deficits that is the hallmark of memory dysfunction resulting from medial temporal lobe damage.
InvIncrements: incremental software to support visual simulation

This paper describes incremental software to support interactive visual simulation. The software was used in the classroom so that students could modify a common prototype code to create diverse applications. In the prototype application, parameters of the simulation are controlled through the use of 3D widgets. The software, based on Open Inventor, has been tested in the classroom (Fall 2002) for Linux and Irix systems, and is available on the World Wide Web.
Primitives and central detection numbers in group cohomology

Abstract Fix a prime p . Given a finite group G , let H ∗ ( G ) denote its mod p cohomology. In the early 1990s, Henn, Lannes, and Schwartz introduced two invariants d 0 ( G ) and d 1 ( G ) of H ∗ ( G ) viewed as a module over the mod p Steenrod algebra. They showed that, in a precise sense, H ∗ ( G ) is respectively detected and determined by H d ( C G ( V ) ) for d ⩽ d 0 ( G ) and d ⩽ d 1 ( G ) , with V running through the elementary abelian p -subgroups of G . The main goal of this paper is to study how to calculate these invariants. We find that a critical role is played by the image of the restriction of H ∗ ( G ) to H ∗ ( C ) , where C is the maximal central elementary abelian p -subgroup of G . A measure of this is the top degree e ( G ) of the finite dimensional Hopf algebra H ∗ ( C ) ⊗ H ∗ ( G ) F p , a number that tends to be quite easy to calculate. Our results are complete when G has a p -Sylow subgroup P in which every element of order p is central. Using the Benson–Carlson duality, we show that in this case, d 0 ( G ) = d 0 ( P ) = e ( P ) , and a similar exact formula holds for d 1 . As a bonus, we learn that H e ( G ) ( P ) contains nontrivial essential cohomology, reproving and sharpening a theorem of Adem and Karagueuzian. In general, we are able to show that d 0 ( G ) ⩽ max { e ( C G ( V ) ) | V G } if certain cases of Benson's Regularity Conjecture hold. In particular, this inequality holds for all groups such that the difference between the p -rank of G and the depth of H ∗ ( G ) is at most 2. When we look at examples with p = 2 , we learn that d 0 ( G ) ⩽ 14 for all groups with 2-Sylow subgroup of order up to 64, with equality realized when G = SU ( 3 , 4 ) . En route we study two objects of independent interest. If C is any central elementary abelian p -subgroup of G , then H ∗ ( G ) is an H ∗ ( C ) -comodule, and we prove that the subalgebra of H ∗ ( C ) -primitives is always Noetherian of Krull dimension equal to the p -rank of G minus the p -rank of C . If the depth of H ∗ ( G ) equals the rank of Z ( G ) , we show that the depth essential cohomology of G is nonzero (reproving and extending a theorem of Green), and Cohen–Macauley in a certain sense, and prove related structural results.
Evolutionary economics goes mainstream: A review of the theory of learning in games

The Theory of Learning in Games by Fudenberg and Levine surveys a key branch of evolutionary economics from a mainstream perspective. Its publication provides an opportunity to reassess the prospects and goals for evolutionary economics.
What is Odontopyge? A solution to a long-standing nomenclatorial enigma in the Diplopoda (Spirostreptida Odontopygidae)

The generic characters of Odontopyge kollarii Brandt 1841, type species of Odontopyge, have never been established with the result that association of the name with an actual species-group has been purely subjective and arbitrary. Although the original type specimen appears to be lost, a careful comparison of the detailed description with material taken near the type locality in the Sudan suggests very conclusively that kollarii is a senior synonym to Omopyge zavattarii Manfredi 1941. Since Omopyge has generally been regarded as distinct from other taxa of the Odontopygidae at the subfamily level, substantial nomenclatorial modifications are mandated by the proposed identification of O. kollarii and a revised classification of the family is provided. The many species previously referred to Odontopyge (sensu auct.) must be referred to other genera, some of which are still undefined.
Method for the Selective Formation of Dimethyl Acetals in the Presence of Hydroxylamine

Abstract An inexpensive and mild method for the formation of dimethyl acetals from the corresponding aldehydes is achieved using hydroxylamine and methanol under neutral conditions at room temperature. Notably, the reaction is selective for aldehydes in the presence of ketones, rendering this an example of a chemoselective acetalization. For saturated, sterically accessible aldehydes, catalytic amounts of hydroxylamine may be employed to attain the corresponding dimethyl acetal as the sole product in good to excellent yield. Unsaturated and hindered aldehydes required stoichiometric amounts of hydroxylamine but provided dimethyl acetals as the major product in typically excellent yield. In some cases, the corresponding oxime was also observed but may be separated from the acetal by flash column chromatography or distillation. The involvement of an intermediate oxime compound is postulated. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communicatio...
Alkaloid synthesis via [3+2] cycloadditions

Tin-lithium exchange on (2-azaallyl)stannanes affords nonstabilized 2-azaallyl- lithiums (2-azaallyl anions) that undergo (π4s+π2s) cycloadditions with alkenes to afford pyrrolidines. The scope of this method has been expanded to include 2-azapentadienyllithi- ums and heteroatom-substituted 2-azaallyllithiums. Alternatively, the (2-azaallyl)stannanes may also be used to generate nonstabilized azomethine ylides via N-alkylation/destannyla- tion or N-protonation/destannylation, and these ylides were also found to be useful for the synthesis of pyrrolidines by (π4s+π2s) cycloadditions with alkenes. Applications of both methods to the total synthesis of alkaloids such as (+)-coccinine, lepadiformine stereoiso- mers, lapidilectine B, and indolizidine 239CD have been accomplished.
The aza-Achmatowicz rearrangement: a route to useful building blocks for N-containing structures

Abstract N-Acyl 2-furylamines were transformed into 2-alkyl-6-methoxy-hexahydropyridin-3-ones. The rearranged products are useful building blocks for the total synthesis of alkaloids and unusual aminoacids.
Mild Decarboxylative Activation of Malonic Acid Derivatives by 1,1′-Carbonyldiimidazole

Malonic acid derivatives undergo unusually mild decarboxylation when treated with N,N'-carbonyldiimidazole (CDI) at room temperature to generate the carbonyl imidazole moiety in high yield, which can be reacted further with a variety of nucleophiles in an efficient one-pot process.
Gamma ray attenuation in X-ray binaries: An application to LSI +61 303

The X-ray binary LSI + 61°303 consisting of a main-sequence Be star and a compact object has been detected in the TeV range with MAGIC and VERITAS, and showed a clear intensity modulation as a function of the orbital phase. We describe a gamma-ray attenuation model and apply it to this system. Our first result is that interaction of high energy photons with the background radiation produced by the main-sequence star alone does not account for the observed modulation. We then include interactions between very high energy radiation and matter and are able to constrain fundamental parameters of the system such as the mass of the compact object and the density of circumstellar matter around the Be star. In our analysis of the TeV data, we find that the compact object has mass M 2 > 2.5 M ☉ at the 99% confidence level, implying it is most likely a black hole. However, we find a column density which conflicts with results from X-ray observations, suggesting that attenuation may not play an important role in the modulation.
D-modules on the affine flag variety and representations of affine Kac-Moody algebras

We study the connection between the category of modules over the affine Kac-Moody Lie algebra at the critical level, and the category of D-modules on the affine flag scheme G((t))/I, where I is the Iwahori subgroup. We prove a localization-type result, which establishes an equivalence between certain subcategories on both sides. We also establish an equivalence between a certain subcategory of Kac-Moody modules, and the category of quasi-coherent sheaves on the scheme of Miura opers for the Langlands dual group, thereby proving a conjecture of [FG2].
Flame front geometry in premixed turbulent flames

Experimental and numerical determinations of flame front curvature and orientation in premixed turbulent flames are presented. The experimental data is obtained from planar, cross sectional images of stagnation point flames at a high Damkohler number (80) and turbulent Reynolds number of 60. A direct numerical simulation of constant energy turbulent flow is combined with a zero-thickness, constant density flame model to provide the numerical results. The two-dimensional curvature distributions of the experiments and numerical simulations compare well at q′ / S L =0.5 with mean values close to zero and significant negative skewness. At higher turbulence levels the simulations show that the distributions become symmetric about zero. These features are also found in the three dimensional distributions of curvature. The simulations support assumptions which make it possible to estimate the true mean direction cosine from two-dimensional images. The effect of these assumptions on the flame surface area density is a 12% reduction in comparison with the value determined directly from the planar data.
Determination of Structure and Phase Transition of Light Element Nanocomposites in Mesoporous Silica: Case study of NH3BH3 in MCM-41

Nanocomposition of molecular crystal ammonia borane (AB) by embedding it in mesoporous silica leads to a remarkable enhancement of the hydrogen storage properties. To investigate the nature of a nanophase AB, we used atomic pair distribution function (PDF) analysis of synchrotron X-ray powder diffraction data to follow the structural evolution of AB embedded within MCM-41 at temperatures ranging from 80 to 300 K. We found that the nanophase AB residing within the mesoporous scaffold does not undergo the structural phase transition at 225 K that was observed in the neat molecular crystal. Rather, it stays in the tetragonal phase over a wide temperature range of 110 to 240 K and starts to lose structural correlation above 240 K. This finding strongly suggests that nanoconfinement of AB within mesoporous scaffolds stabilizes the high-temperature disordered tetragonal phase at a much lower temperature. PDF analyses of composite materials composed of excess AB (i.e., AB:MCM-41 > 1:1) indicates that the excess AB forms aggregates outside the mesoporous scaffold and that these aggregates have structural properties similar to neat AB, that is, the orthorhombic-to-tetragonal structural phase transition is observed at 225 K upon warming. These results may provide important insight into the mechanism behind the enhanced hydrogen storage properties of this system.
A strong log-concavity property for measures on Boolean algebras

We introduce the antipodal pairs property for probability measures on finite Boolean algebras and prove that conditional versions imply strong forms of log-concavity. We give several applications of this fact, including improvements of some results of Wagner, a new proof of a theorem of Liggett stating that ultra-log-concavity of sequences is preserved by convolutions, and some progress on a well-known log-concavity conjecture of J. Mason.
Monoclonal Gammopathy of Undetermined Significance and Smoldering Multiple Myeloma

Monoclonal gammopathy of undetermined significance (MGUS) is characterized by the presence of a serum monoclonal (M) protein level less than 3 g/dL, less than 10% clonal plasma cells in the bone marrow, and the absence of hypercalcemia, renal insufficiency, anemia, or bone lesions attributable to a clonal plasma cell disorder. Patients may be tested for a monoclonal gammopathy by serum protein electrophoresis, immunofixation, and the free light chain (FLC) assay. The prevalence of MGUS is 3% for persons more than 50 years of age and 5% in those more than 70 years of age. The risk of progression to multiple myeloma or a related disorder is 1% per year. The size and type of M protein, the number of bone marrow plasma cells, and the results of the FLC ratio are independent risk factors for progression. Smoldering multiple myeloma (SMM) is a more advanced premalignant phase than MGUS and is characterized by more than 3 g/dL of serum M protein, more than 10% clonal plasma cells in the bone marrow, or both, with no evidence of end-organ damage.
A Configurable Network Protocol for Cluster Based Communications using Modular Hardware Primitives on an Intelligent NIC

The high overhead of generic protocols like TCP/IP provides strong motivation for the development of a better protocol architecture for cluster-based parallel computers. Reconfigurable computing has a unique opportunity to contribute hardware level protocol acceleration while retaining the flexibility to adapt to changing needs. Specifically, applications on a cluster have various quality of service needs. In addition, these applications typically run for a long time relative to the reconfiguration time of an FPGA. Thus, it is possible to provide application-specific protocol processing to improve performance and reduce space utilization. Reducing space utilization permits the use of a greater portion of the FPGA for other application-specific processing. This paper focuses on work to create a set of parameterizable components that can be put together as needed to obtain a customized protocol for each application. To study the feasibility of such an architecture, hardware components were built that can be stitched together as needed to provide the required functionality. Feasibility is demonstrated using four different protocol configurations, namely: (1) unreliable packet transfer; (2) reliable, unordered message transfer without duplicate elimination; (3) reliable, unordered message transfer with duplicate elimination; and (4) reliable, ordered message transfer with duplicate elimination. The different configurations illustrate trade-offs between chip space and functionality.
K2[HCr2AsO10]: redetermination of phase II and the predicted structure of phase I.

Our prediction that phase II of dipotassium hydrogen chromatoarsenate, K2[HCr2AsO10], is ferroelectric, based on the analysis of the atomic coordinates by Averbuch-Pouchot, Durif & Guitel [Acta Cryst. (1978), B34, 3725–3727], led to an independent redetermination of the structure using two separate crystals. The resulting improved accuracy allows the inference that the H atom is located in the hydrogen bonds of length 2.555 (5) A which form between the terminal O atoms of shared AsO3OH tetrahedra in adjacent HCr2AsO102− ions. The largest atomic displacement of 0.586 A between phase II and the predicted paraelectric phase I is by these two O atoms. The H atoms form helices of radius ∼0.60 A about the 31 or 32 axes. Normal probability analysis reveals systematic error in seven or more of the earlier atomic coordinates.
Ionic liquids via efficient, solvent-free anion metathesis

A range of electrophilic reagents have been found to facilitate simultaneous halide-trapping/anion metathesis of halide-containing salts in the absence of solvent to afford ionic liquids bearing non-nucleophilic, non-coordinating anions.
Normalized floating-point arithmetic with an index of significance

It has been frequently pointed out that the task of determining an error-bound for the results of a problem is usually a long difficult calculation, which is avoided as much as possible by the programmer. The introduction of floating-point arithmetic in modern computers and the ever-growing use of compilers makes the task of error analysis even more difficult and its computation even less probable. Clearly, a machine method is needed to automatically calculate a bound for the propagated and generated error, given the initial error in the input and the residual error due to approximating functions.
Light propagation in inhomogeneous universes. I. Methodology and preliminary results

We describe a numerical algorithm that simulates the propagation of light in inhomogeneous universes. This algorithm computes the trajectories of light rays between the observer, located at redshift z = 0, and distant sources located at high redshift using the multiple lens plane method. The deformation and deflection of light beams as they interact with each lens plane are computed using the filled-beam approximation. We use a particle-particle/particle-mesh (P3M) N-body numerical code to simulate the formation of large-scale structure in the universe. We extend the length resolution of the simulations to submegaparsec scales by using a Monte Carlo method for locating galaxies inside the computational volume according to the underlying distribution of background matter. The observed galaxy two-point correlation function is reproduced. This algorithm constitutes a major improvement over previous methods, which either neglected the presence of large-scale structure, neglected the presence of galaxies, neglected the contribution of distant matter (matter located far from the beam), or used the Zeldovich approximation for simulating the formation of large-scale structure. In addition, we take into account the observed morphology-density relation when assigning morphological types to galaxies, something that was ignored in all previous studies. To test this algorithm, we perform 1981 simulations for three different cosmological models: an Einstein-de Sitter model with density parameter Ω0 = 1, an open model with Ω0 = 0.2, and a flat, low-density model with Ω0 = 0.2 and a cosmological constant of λ0 = 0.8. In all models, the initial density fluctuations correspond to a cold dark matter power spectrum normalized to COBE. In each simulation, we compute the shear and magnification resulting from the presence of inhomogeneities. Our results are the following: (1) The magnification is totally dominated by the convergence, with the shear contributing less than one part in 104. (2) Most of the cumulative shear and magnification is contributed by matter located at intermediate redshifts, z = 1-2. (3) The actual value of the redshift at which the largest contribution to shear and magnification occurs depends on the cosmological model. In particular, the lens planes contributing the most are located at larger redshift for models with smaller Ω0. (4) The number of galaxies directly hit by the beam increases with redshift, while the contribution of lens planes to the shear and magnification decrease with increasing lens plane redshift for z > 2, which indicates that the bulk of the shear and magnification does not originate from direct hits, but rather from the tidal influence of nearby and more distant galaxies and background matter. (5) The average contributions of background matter and nearby galaxies to the shear is comparable for models with small Ω0. For the Einstein-de Sitter model, the contribution of the background matter exceeds the contribution of nearby galaxies by nearly 1 order of magnitude.
Extra states and symmetries in D<2 closed string theory

Abstract We show that there is ( p −1)( p ′−1)-dimensional semi-relative BRST cohomology at each non-positive ghost number in the ( p , p ′) minimal conformal field theory coupled to two-dimensional quantum gravity. These closed string states are related to currents and symmetry charges of “exotic” ghost number. We investigate the symmetry structure generated by the most conventional currents (those of vanishing total ghost number), and make a conjecture about the extended algebra which results from incorporating the currents at negative ghost numbers.
Radio observations of molecules in the interstellar gas

Since 1968, radio astronomy has made it possible to identify nearly 50 molecules in the dense concentrations of the interstellar gas now generally termed molecular clouds. Most interstellar molecules are familiar stable compounds. However, one-fifth of the discovered species are ions, radicals, and acetylenic carbon chains so reactive in the laboratory that before being detected in space they had rarely been observed or were entirely unknown. The heavy atom backbone of the known interstellar molecules is a linear chain of C, N, O, or S. Si is found in two diatomic molecules. Rings and branched chains are missing. The most readily observed spectral lines of most interstellar molecules correspond to rotational transitions at millimeter wavelengths. These are generally excited by H2 collisions. A number of rare isotopic species are observed in interstellar molecules. Isotopic ratios differing from those on Earth exist, and can in almost all cases be attributed to stellar nucleosynthesis since the formation of the solar system.
Generalized inflow performance relationships for three-phase flow

Inflow performance relationships (IPRs) are empirical relationships based on linear regression analysis of simulator results that cover a wide range of reservoir fluid and rock properties. The IPRs developed are compared with other three-phase methods and yield similar results for production-pressure behavior during boundary-dominated flow while being much simpler to use. The proposed IPRs were developed from analysis of multiphase flow in bounded, homogeneous reservoirs without external influx of fluids into the reservoir and apply to the boundary-dominated flow regime. The relationships are limited by the assumptions that (1) the reservoirs are initially at the bubblepoint, (2) no initial free gas phase is present, (3) a mobile water phase is present for three-phase studies, (4) Darcy's law for multiphase flow applies, (5) isothermal conditions exist, (6) no reactions take place between reservoir fluids and reservoir rock, (7) no gas solubility exists in the water, (8) gravity effects are negligible, and (9) the wellbore is fully penetrating.
Symmetrically constrained compositions

Given integers a1,a2,…,an, with a1+a2+⋅⋅⋅+an≥1, a symmetrically constrained composition λ1+λ2+⋅⋅⋅+λn=M of M into n nonnegative parts is one that satisfies each of the n! constraints \(\{\sum_{i=1}^{n}a_{i}\lambda_{\pi(i)}\geq 0:\pi \in S_{n}\}\). We show how to compute the generating function of these compositions, combining methods from partition theory, permutation statistics, and lattice-point enumeration.
PARTICLE PHYSICS, FROM RUTHERFORD TO THE LHC

Our understanding of fundamental particles has developed in ways that were unimaginable 100 years ago, when the atomic nucleus was first glimpsed.
Structure Elucidation of (+)-Amphidinolide A by Total Synthesis and NMR Chemical Shift Analysis

The structure elucidation of (+)-amphidinolide A, a cytotoxic macrolide, has been accomplished by employing a combination of NMR chemical shift analysis and total synthesis. Using the reported structure as a starting point, a number of diastereomers of amphidinolide A were prepared. The deviations of the chemical shifts of key protons in each isomer relative to the values reported for the isolated material were used to determine the locations of the errors in relative stereochemistry. The spectroscopic data for our proposed structure of (+)-amphidinolide A and the isolated material are in excellent agreement. The key step, a [Cp*Ru(MeCN)3]PF6-catalyzed alkene−alkyne coupling, was used to form the 20-membered ring in the final step of the synthesis.
Foreign-Born Teaching Assistants and the Academic Performance of Undergraduates

The large literature that analyzes the impact of immigration on the United States typically focuses on measuring the labor market and fiscal consequences. This literature, however, has ignored the impact of immigration on other sectors of society. One sector that is of great interest is the American university, where the share of nonresident aliens in the graduate student population rose from 5.5 percent in 1976 to 10.5 percent in 1996. Despite the rapid growth in the number of foreign students, little is known about their impact on the educational process. Nevertheless, undergraduates frequently complain that the lack of English language proficiency among many foreign-born Teaching Assistants affects adversely their understanding of the material. This paper addresses the question that is at the heart of these complaints: Do foreign-born teaching assistants have an adverse impact on the scholastic achievement of American undergraduates? To provide empirical evidence on this issue, I use data drawn from a survey of undergraduates enrolled in economics principles classes at a large public university. The data suggest that foreign-born Teaching Assistants have an adverse impact on the class performance of undergraduate students.
ON COST-OPTIMAL MERGE OF TWO INTRANSITIVE SORTED SEQUENCES

The problem of merging two intransitive sorted sequences (that is, to generate a sorted total order without the transitive property) is considered. A cost-optimal parallel merging algorithm is proposed under the EREW PRAM model. This algorithm has a run time of O(log2 n) using O(n/log2 n) processors. The cost-optimal merge in the strong sense is still an open problem.
Chemical synthesis of spun-on thick films of oxide superconductors

Abstract Films of YBa 2 Cu 3 O 7− x were deposited by a metal organic decomposition onto single crystals of MgO and Al 2 O 3 , polycrystalline Ag, and stabilized ZrO 2 substrates by spin coating. The precursor solution of metal acetates dissolved in citric acid and ethylene glycol were found to produce films which decomposed without surface damage. The surfaces of the samples, examined by a profilometer, were found to be continuous, smooth and had good adherence to all of the substrates. The films showed a broad superconducting transition temperature starting at 89 K.
Purin-8-ones as corticotropin-releasing hormone (CRH-R1) receptor antagonists

A series of purin-8-ones was prepared and discovered to have excellent binding affintity to the CRH-R1 receptor. Structure-activity studies focused on amine side-chain optimization, urea substitution and pyridyl isostere incorporation. Thus, the highly potent purin-8-ones show promise as a new class of potential anxiolytics and/or antidepressants.
Codes over rings of size four, Hermitian lattices, and corresponding theta functions

Let K = Q(√-l) be an imaginary quadratic field with ring of integers O K, where l is a square free integer such that l ≡ 3 mod 4, and let C = [n, k] is a linear code defined over O k /2O k . The level I theta function Θ Λl (C) of C is defined on the lattice Λ l (C):= {x ∈ O n k : ρ l (x) ∈ C}, where ρl O K → O K /20 K is the natural projection. In this paper, we prove that: i) for any l,l' such that l≤l', ⊖Λ l (q) and ⊖Λ l' (q) have the same coefficients up to q l+1/4, ii) for l ≥ 2(n+1)(n+2)/n -1, ⊖Λ l (C) determines the code C uniquely, iii) for l < 2(n+1)(n+2)/n - 1, there is a positive dimensional family of symmetrized weight enumerator polynomials corresponding to ⊖ Λl (C).
Surface changes on Io during the Galileo mission

Abstract A careful survey of Galileo SSI global monitoring images revealed more than 80 apparent surface changes that took place on Io during the 5 year period of observation, ranging from giant plume deposits to subtle changes in the color or albedo of patera surfaces. Explosive volcanic activity was discovered at four previously unrecognized centers: an unnamed patera to the south of Karei that produced a Pele-sized red ring, a patera to the west of Zal that produced a small circular bright deposit, a large orange ring detected near the north pole of Io, and a small bright ring near Io's south pole. Only a handful of Io's many active volcanoes produced large scale explosive eruptions, and several of these erupted repeatedly, leaving at least 83% of Io's surface unaltered throughout the Galileo mission. Most of the hot spots detected from SSI, NIMS and ground-based thermal observations caused no noticeable surface changes greater than 10 km in extent over the five year period. Surface changes were found at every location where active plumes were identified, including Acala which was never seen in sunlight and was only detected through auroral emissions during eclipse. Two types of plumes are distinguished on the basis of the size and color of their deposits, confirming post-Voyager suggestions by McEwen and Soderblom [Icarus 55 (1983) 191]. Smaller plumes produce near-circular rings typically 150–200 km in radius that are white or yellow in color unless contaminated with silicates, and frequently coat their surroundings with frosts of fine-grained SO2. The larger plumes are much less numerous, limited to a half dozen examples, and produce oval, orange or red, sulfur-rich rings with maximum radii in the north-south direction that are typically in the range from 500 to 550 km. Both types of plumes can be either episodic or quasi-continuous over a five year period. Repeated eruptions of the smaller SO2-rich plumes likely contribute significantly to Io's resurfacing rate, whereas dust ejection is likely dominated by the tenuous giant plumes. Both types of plume deposits fade on time-scales of months to years through burial and alteration. Episodic seepages of SO2 at Haemus Montes, Zal Montes, Dorian Montes, and the plateau to the north of Pillan Patera may have been triggered by activity at nearby volcanic centers.
The molecular structure and conformation of 2-chlorocyclohexanone as determined by gas-phase electron diffraction

Abstract The molecular structure and conformation of 2-chlorocyclohexanone have been determined by gas-phase electron diffraction at a nozzle temperature of 103°C. The molecules exist as a mixture of two conformers, axial and equatorial. The mole fraction of axial form is found to be 0.80 ± 0.06, corresponding to a free energy value of 1.0 ± 0.3 kcal mol−1. The results for the distance (rg) and angle (∠α) parameters obtained with an estimated uncertainty of 3σ are: r( C  H ) = 1.098(5), r( C = O ) = 1.211(2), r( C  C =) av = 1.501(3), r( C | C ) av = 1.546(2), r( C  Cl ) = 1.799(4) A , ∠ O=C| = 124.6(0.5), ∠CCC = 115.7(10), ∠ClCC = 110.2(5), τC6C2C3 = 48.4(15)° and FLAPC (angle between planes formed by atoms C3C4C5 and C2C3C5) = 51.0(2)°.
Editorial: The vulnerable physician-scientist.

A new era of academic medicine is upon us. The current funding climate for research has many medical schools throughout the United States initiating new strategies to conserve costs while still trying to maintain excellence in their tripartite mission of research, education, and clinical care. New measures have been instituted at many schools in which faculty salaries must be balanced by sources of income, including effort on extramural grants, clinical relative value units, educational relative value units, and administrative effort, among others. With its clinical and research skills, one group of individuals, the physician-scientist, is particularly well equipped to face these new challenges. In his book, The Vanishing Physician-Scientist? (1), Andrew Schafer broadly defines a physician-scientist as a physician (with an MD degree or an MD combined with other advanced degrees) who spends most of his/her professional effort engaging in research that seeks knowledge about human health and disease. Because the nature of biomedical research has changed over the decades, so too has the nature and breadth of research conducted by physician-scientists (ranging from basic laboratory studies to translational studies involving human tissues, humans, or human populations). Physician-scientists can engage in all aspects of the medical school tripartite mission, and are seemingly highly marketable. Physician-scientists are also natural candidates for leadership positions (eg, department chairs, center directors, and deans), because they are among the few individuals who can bridge crucial clinical and research issues at the administrative level. But their marketability may very well be their vulnerability in the current academic climate. Recent statistics reported by the National Institutes of Health (NIH) and others identify worrisome trends in pre- and postdoctoral training that cast some doubt on the future of physician-scientists in academics.
The r-rank of the groups of exceptional Lie type

Abstract In this note, we prove the following result, settling a question raised at the end of [Borel & Serre 1953], cf. [Borel 1983 pp. 228 and 708]. A related result for Lie groups of type E 8 was recently proved by J.F. Adams.
On spectral properties of finite population processor shared queues

We consider sojourn or response times in processor-shared queues that have a finite population of potential users. Computing the response time of a tagged customer involves solving a finite system of linear ODEs. Writing the system in matrix form, we study the eigenvectors and eigenvalues in the limit as the size of the matrix becomes large. This corresponds to finite population models where the total population is $$N\gg 1$$ . Using asymptotic methods we reduce the eigenvalue problem to that of a standard differential equation, such as the Hermite equation. The dominant eigenvalue leads to the tail of a customer’s sojourn time distribution.
The science of reverse osmosis-mechanisms, membranes, transport and applications

Abstract A view of the science of reverse osmosis on the basis of the preferential sorption-capillary flow mechanism is presented. Preferential sorption at the membrane-solution interface is a function of solute-solvent-membrane material interactions arising from polar-, steric-, nonpolar-, and/or ionic-character of each one of the above components. Quantitative parameters for characterizing solutes and membrane materials at aqueous solution-membrane interfaces have been generated. Basic transport equations suitable for membrane specification and system analysis, and applicable for all membrane materials and membranes at all levels of solute separations have been developed for reverse osmosis systems involving aqueous solutions and preferential sorption of water at the membrane-solution interface. The polar, steric, and nonpolar parameters characterizing solutes have been built into the above transport equations through appropriate additional equations and correlations. As a result, it is now possible to predict the performance of a membrane for a large number of single and mixed solute aqueous feed solutions from only a single set of experimental reverse osmosis data for a reference NaCl-H 2 O feed solution. This is illustrated.
A new directed synthesis of enol borates from gem-borazirconocene alkanes, and their regioselective conversion to α-bromo ketones

Abstract Reaction of acid chlorides and gem-borazirconocene alkanes produces enol borates by rearrangement of α-bora ketones. Reaction of the enol borates with NBS occurs with complete regioselectivity to give unsymmetrical α-bromo ketones.