cssi/SciSciGPT-SciSciNet huggingface dataset:
High-Redshift Intergalactic C IV Abundance Measurements from the Near-Infrared Spectra of Two z ~ 6 QSOs

New measurements of the z ~ 6 intergalactic C IV abundance are presented, using moderate-resolution IR spectra of two QSOs taken with GNIRS on Gemini-South. These data were systematically searched for high-redshift C IV absorption lines, using objective selection criteria. Comprehensive tests were performed to quantify sample incompleteness, as well as the rate of false-positive C IV identifications. The trend of constant Ω(z) observed at z ~ 2-5 appears to continue to z ~ 6, the highest observed redshift. The C IV sample is also consistent with the redshift-invariant form of the C IV column density distribution reported by Songaila at lower redshift, although with fairly large uncertainties due to a smaller sample size and noisier infrared data. The constant value of Ω does not necessarily imply that the IGM was infused with an early metallicity floor, but the presence of early C IV does indicate that heavy-element enrichment began 1 Gyr after the big bang. The lack of a decline in Ω at high redshift may indicate that integrated C IV measurements are sensitive to the instantaneous rate of feedback from galaxy formation at each epoch. Alternatively, it could result from a balance in the evolution of the intergalactic gas density, ionization conditions, and heavy-element abundance over time.
Composite Layer-by-Layer (LBL) Assembly with Inorganic Nanoparticles and Nanowires

New assembly techniques are required for creating advanced materials with enough structural flexibility to be tuned for specific applications, and to be practical, the techniques must be implemented at relatively low cost. Layer-by-layer (LBL) assembly is a simple, versatile, and significantly inexpensive approach by which nanocomponents of different groups can be combined to coat both macroscopically flat and non-planar (e.g., colloidal core-shell particles) surfaces. Compared with other available assembly methods, LBL assembly is simpler and more universal and allows more precise thickness control at the nanoscale. LBL can be used to combine a wide variety of species--including nanoparticles (NPs), nanosheets, and nanowires (NWs)--with polymers, thus merging the properties of each type of material. This versatility has led to recent exceptional growth in the use of LBL-generated nanocomposites. This Account will focus on the materials and biological applications of introducing inorganic nanocrystals into polymer thin films. Combining inorganic NPs and NWs with organic polymers allows researchers to manipulate the unique properties in the nanomaterial. We describe the LBL assembly technique for introducing metallic NPs into polymers in order to generate a material with combined optomechanical properties. Similarly, LBL assembly of highly luminescent semiconductor NPs like HgTe or CdTe with poly(diallyldimethylammonium chloride) (PDDA) was used to create uniform optical-quality coatings made on optical fibers and tube interiors. In addition, LBL assembly with inorganic nanosheets or clay molecules is reported for fabricating films with strong mechanical and ion transport properties, and the technique can also be employed to prepare Au/TiO(2) core/sheath NWs. The LBL approach not only will be useful for assembly of inorganic nanocrystals with various polymers but can be further applied to introduce specific functions. We discuss how the expanded use of NWs and carbon nanotubes (CNTs) in nanocomposite materials holds promise in the design of conductive films and new nanoscale devices (e.g., thin-film transistors). New photonic materials, sensors, and amplifiers can be constructed using multilayer films of NPs and can enable fabrication of hybrid devices. On the biological side, inorganic nanoshells were used as assembly tools with the goal of detecting neurotransmitters (specifically, dopamine) directly inside brain cells. In addition, the stability of different cell lines was tested for fabricating biocompatible films using LBL. NP LBL assembly was also used for homogeneous and competitive fluorescence quenching immunoassay studies for biotin and anti-biotin immunoglobulin molecules. Finally, introduction of biomolecules with inorganic NPs for creating biocompatible surfaces could also lead to new directions in the field of biomedical applications.
Landau, Abrikosov, Hofstadter: Magnetic Flux Penetration in a Lattice Superconductor

Abstract Magnetic flux penetration in superconductors involves a rich variety of subtle phenomena, much of which is still poorly understood. Here these complexities are studied by formulating the Ginzburg-Landau equations as a lattice gauge theory. Their solutions are compared and contrasted with the (heuristic) Landau model of type I superconductivity, and the (perturbative) Abrikosov model for type II superconductors. Novelties arise as the continuum limit is approached, related to an effect discovered by Hofstadter. Various cautionary remarks pertinent to large-scale simulations are made.
Reflection-Transmission Relationships in Sheet Materials

Reflectances of transmissive sheets, calculated from the transmissions of one and two sheets, are compared with reflectances obtained by using the General Electric recording spectrophotometer. The expression used as a basis for calculation, Ra=(1−Ta2/T2a)12, in which Ra is the reflectance, and Ta and T2a are the transmissions of one and two sheets, respectively, of a, was derived by considering the infinite series of reflections undergone by light, or radiant energy in general, in passing through the two sheets. The expression was found to be valid and useful over a wide range of reflectances and wave-lengths, for materials such as paper, glass, and an organic plastic.The method is an absolute one since it involves no reflectance standard. It involves no spherical or similar integrating device nor does it involve any reflecting surface other than that of the sample itself, as a fundamental part of the measurements. When transmission values for diffuse incidence are substituted into the expression, the reflectances thus calculated correspond to the conditions of diffuse incidence and diffuse viewing, and as such are somewhat higher than the usual directly measured reflectances for normal incidence and diffuse viewing (or diffuse incidence and normal viewing). For clear sheets, with normal incidence, specular reflectance may be calculated.The method thus affords a means of determining, from two simple measurements, the specular-plus-diffuse reflectance of transmissive sheets for diffused light or radiant energy in general.The expression as derived is theoretically inapplicable to diffusing sheets for light of normal incidence, but a compensation of errors allows close agreement over the visible range, at 365 millimicrons, and for “white” light, for all except tissue paper and other materials of like transmissivity. For diffuse incidence at 365, and to a certain extent, at 405 millimicrons, some papers show deviations from the simple theory because of fluorescence effects. This and other effects are discussed.Reflectances in the infra-red region near 850 millimicrons are also calculated but no standard for comparison is available for these values. The sources of errors at the shorter wave-lengths, however, do not interfere in the infra-red region.Transmissions of papers were found to be dependent upon the angle of incidence.Reflectances throughout the visible region, measured at 45° from normal incidence were found to agree closely, for the type of papers studied, with those obtained using the General Electric recording spectrophotometer, which corresponds to the conditions of normal incidence and diffuse viewing.
Tandem allylboration-ring-closing metathesis reactions for the preparation of biologically active molecules*

The development of asymmetric synthesis during the past two decades aided or- ganic chemists considerably in the synthesis of complex natural products. Organoborane chemistry continues to play an important role in asymmetric synthesis. One of the important reactions that has become very common in the arsenal of synthetic chemists is allylboration and related reactions. Another important reaction that has recently attained enormous impor- tance in organic chemistry is the ring-closing metathesis (RCM) reaction. Indeed, a combi- nation of allylboration and RCM reactions provides an excellent route to cyclic ethers, lac- tones, lactams, etc. Herein, we describe a sequential asymmetric allylboration and RCM reaction protocol that has been utilized for the synthesis of several α-pyrone-containing nat- ural products, particularly biologically active molecules.
Waveform digitizing at 500 MHz

Abstract Experiment E787 at Brookhaven National Laboratory is designed to study the decay K + → π + ν v to a sensitivity of 2 × 10−10. To achieve acceptable muon rejection it is necessary to couple traditional methods (range/energy/momentum correlation) with observation of the decay sequence in scintillator. We report on the design and construction of 200 channels of relatively low cost solid state waveform digitizers. The distinghishing features are: 8 bits dynamic range, 500 MHz sampling, zero suppression on the fly, deep memory (up to 0.5 ms), and fast readout time (100 μs for the entire system). We report on data obtained during the February–May 1988 run showing performance of the system for the observation of the above decay.
Search for High-Frequency Periodicities in Time-tagged Event Data from Gamma-Ray Bursts and Soft Gamma Repeaters

We analyze the time-tagged event (TTE) data from observations of gamma-ray bursts (GRBs) and soft gamma repeaters (SGRs) by the Burst and Transient Source Experiment (BATSE). These data provide the best available time resolution for GRBs and SGRs. We have performed an extensive search for weak periodic signals in the frequency range of 400-2500 Hz using the burst records for 2203 GRBs and 152 SGR flares. The study employs the Rayleigh power as a test statistic to evaluate the evidence for periodic emissions. We find no evidence of periodic emissions from these events at these frequencies. In all but a very few cases, the maximum power values obtained are consistent with what would be expected by chance from a nonperiodic signal. In those few instances in which there is marginal evidence for periodicity, there are problems with the data that cast doubt on the reality of the signal. For classical GRBs, the largest Rayleigh power occurs in bursts whose TTE data appear to be corrupted. For SGRs, our largest Rayleigh power, with a significance of ≈1%, occurs in one record for SGR 1900+14 (at ≈2497 Hz) and in no other outbursts associated with this source; we thus consider it unlikely to represent detection of a real periodicity. From simulations, we deduce that the Rayleigh test would have detected significant oscillations with a relative amplitude of ≈10% about half the time. Thus, we conclude that high-frequency oscillations, if present, must have small relative amplitudes.
Replacing bulk Pt in Pt–Ni–Pt bimetallic structures with tungsten monocarbide (WC): Hydrogen adsorption and cyclohexene hydrogenation on Pt–Ni–WC

Abstract It is well known that bimetallic surfaces, such as the Pt–Ni–Pt(bulk) structure, with one monolayer of Ni residing in the subsurface region of Pt, often show unique catalytic properties including low temperature hydrogenation pathways. It is also known that transition metal carbides, such as tungsten monocarbide (WC), often show catalytic properties similar to Pt. In the current study, we explored the possibility to replace bulk Pt in the Pt–Ni–Pt(bulk) structure by anchoring Pt–Ni on a WC substrate. The dissociative adsorption of hydrogen and the hydrogenation of cyclohexene were used as probe reactions to evaluate the chemical properties of Pt–Ni–WC(bulk), with Density Functional Theory (DFT) calculations and Temperature Programmed Desorption (TPD) measurements being performed. Similar to Pt–Ni–Pt, the Pt–Ni–WC surface shows weakly bonded hydrogen as predicted from DFT calculations and confirmed by TPD experiments. In addition, the presence of weakly bonded atomic hydrogen and cyclohexene led to the low temperature hydrogenation of cyclohexene, again similar to that observed on Pt–Ni–Pt. Our results indicate that anchoring the Pt–Ni structure on WC should potentially reduce the loading of Pt in the bimetallic catalysts. Furthermore, the replacement of bulk Pt by WC should also prevent the diffusion of the subsurface Ni into the bulk, potentially increasing the stability of the desirable subsurface bimetallic structure in Pt–Ni–WC.
Radical Addition of Dimethyl 2‐Ethynylcyclopropane‐1,1‐dicarboxylate to Electron‐Rich Olefins

Abstract The phenylseleno radical–catalyzed addition of dimethyl 2‐ethynylcyclopropane‐1,1‐dicarboxylate to electron–rich olefins has been achieved. This radical process leads to formation of highly substituted ethynylcyclopentane products through a [3+2] annulation.
The vanishing viscosity limit of statistical solutions of the Navier-Stokes equations. II. The general case

Abstract We study problems of vanishing viscosity limit of statistical solutions of the Navier-Stokes equation in 3-D and general boundary conditions in 2-D. In this case due to lack of sufficiently strong estimate besides energy type one we can have only weak convergence in the limit. By a statistical extension of the generalized Young measure theorem of R. DiPerna and A. Majda we show that a weak limit is a measure valued solution of the Euler equation. As another corollary of the extended Young measure theorem we show that any statistical solution generates measure valued solutions in a canonical fashion.
Suzuki−Miyaura Cross-Coupling of Potassium Trifluoroboratohomoenolates

Ketone-, ester-, and amide-containing potassium trifluoroboratohomoenolates were prepared in good to excellent yields from the corresponding unsaturated carbonyl compounds. They were shown to be effective coupling partners in the Suzuki-Miyaura reaction with a variety of electrophiles including electron-rich and electron-poor aryl bromides and -chlorides.
One-flask synthesis of meso-substituted dipyrromethanes and their application in the synthesis of trans-substituted porphyrin building blocks

Abstract The reaction at room temperature of an aldehyde with excess pyrrole in the absence of solvent affords the meso-substituted dipyrromethane. The reaction is catalyzed with trifluoroacetic acid or with BF3ṡO(Et)2. The dipyrromethane is purified by crystallization or by flash chromatography on silica with eluants containing 1% triethylamine. The reaction is compatible with aliphatic or aromatic aldehydes, including 2,6-disubstituted benzaldehydes. Nine dipyrromethanes have been prepared in this manner in yields of 47–86%, indicating the broad scope of the reaction. The dipyrromethanes are stable in the purified form in the absence of light and air. Similar reaction with terephthalaldehyde and pyrrole affords the corresponding bis-dipyrromethane. The reaction of a meso-substituted dipyrromethane with an aldehyde under the conditions of the two-step one-flask porphyrin synthesis affords a direct route to trans-substituted meso-porphyrins. Acidolysis of the dipyrromethane is negligible under the conditions of the porphyrin-forming reaction. Four porphyrins bearing peripheral functional groups and facially-encumbering groups have been prepared which serve as key building blocks in the synthesis of linear porphyrin arrays.
APT: what it has enabled us to do

With the development and operations deployment of the Astronomer's Proposal Tool (APT), Hubble Space Telescope (HST) proposers have been provided with an integrated toolset for Phase I and Phase II. This toolset consists of editors for filling out proposal information, an Orbit Planner for determining observation feasibility, a Visit Planner for determining schedulability, diagnostic and reporting tools and an integrated Visual Target Tuner (VTT) for viewing exposure specifications. The VTT can also overlay HST’s field of view on user-selected Flexible Image Transport System (FITS) images, perform bright object checks and query the HST archive. In addition to these direct benefits for the HST user, STScI’s internal Phase I process has been able to take advantage of the APT products. APT has enabled a substantial streamlining of the process and software processing tools, which enabled a compression by three months of the Phase I to Phase II schedule, allowing to schedule observations earlier and thus further benefiting HST observers. Some of the improvements to our process include: creating a compact disk (CD) of Phase I products; being able to print all proposals on the day of the deadline; link the proposal in Portable Document Format (PDF) with a database, and being able to run all Phase I software on a single platform. In this paper we will discuss the operational results of using APT for HST's Cycles 12 and 13 Phase I process and will show the improvements for the users and the overall process that is allowing STScI to obtain scientific results with HST three months earlier than in previous years. We will also show how APT can be and is being used for multiple missions.
Multiscale modeling of binary polymer mixtures: Scale bridging in the athermal and thermal regime

Obtaining a rigorous and reliable method for linking computer simulations of polymer blends and composites at different length scales of interest is a highly desirable goal in soft matter physics. In this paper a multiscale modeling procedure is presented for the efficient calculation of the static structural properties of binary homopolymer blends. The procedure combines computer simulations of polymer chains on two different length scales, using a united atom representation for the finer structure and a highly coarse-grained approach on the mesoscale, where chains are represented as soft colloidal particles interacting through an effective potential. A method for combining the structural information by inverse mapping is discussed, allowing for the efficient calculation of partial correlation functions, which are compared with results from full united atom simulations. The structure of several polymer mixtures is obtained in an efficient manner for several mixtures in the homogeneous region of the phase diagram. The method is then extended to incorporate thermal fluctuations through an effective χ parameter. Since the approach is analytical, it is fully transferable to numerous systems.
The challenge of characterizing branching in molecular species

Abstract A precise definition of the concept of branching as applied to molecular species has been an objective of chemists for several decades and still remains a challenge today. Although the problem has been tackled in many ingenious ways, no completely satisfactory resolution can be said to have been achieved. The reason for this is that there are two fundamental difficulties confronting the researcher in this field. These are that (i) a universally agreed difinition of branching appears to be unattainable because ultimately the concept can be defined only in intuitive terms; and (ii) any mathematical measure used to characterize the branching in molecular species must also accurately reflect the physicochemical properties of those species. It also has to be borne in mind that different properties are know to be associated with different orderings. In this survey of the field, the current state of the art in characterizing molecular branching is reviewed and the prospects for future advances are assessed. In physical science … the most important and most fruitful concepts are those to which it is impossible to attach a well-defined meaning. H.A. Kramers (1947)
Temporal Evolution of GP Zones in an Al-Ag Alloy

Summary from only given. In the phase-separating Al-Ag system, intermediate metastable precipitates (Guinier Preston zones) are formed. The metastable miscibility gap is characterized by a large asymmetry with a gap extending to ~55 at.% Ag below 175degC and to ~30 at.% Ag above 220degC. The exact structure of the GP zones (ordering, Ag concentration) and the existence of temperature-dependent phases (ordered at low T and disordered at high T) is still a matter of debate and the experimental studies published on this system have yet to concur. Previous atom probe studies have confirmed the variations of GP zone concentration with temperature and a more recent work by Al-Kassab et al. showed the coexistence of two types of precipitates. Recent TEM observations have also indicated that in the initial stages of decomposition, GP zones form with a surprising morphology consisting of a Ag-rich shell surrounding an Al-rich inner core. This paper discusses our recent transmission electron microscopy and atom probe tomography measurements of the three-dimensional Ag concentration in precipitates, including the temporal evolution
Quality leadership when regulatory standards are forthcoming

In many markets, governments set minimum quality standards while some sellers compete on the basis of quality by exceeding them. Such quality leadership strategies often win public acclaim, especially when they involve environmental attributes. Using a duopoly model of vertical product differentiation, we show that if the high-quality firm can commit to a quality level before regulations are promulgated, it induces the regulator to weaken standards, and welfare falls. Our results raise doubts about the social benefits of corporate self-regulation, and highlight the dangers of lengthy delays between legislative mandates for new regulations and their implementation.
Low-dimensional embedding of fMRI datasets.

Abstract We propose a novel method to embed a functional magnetic resonance imaging (fMRI) dataset in a low-dimensional space. The embedding optimally preserves the local functional coupling between fMRI time series and provides a low-dimensional coordinate system for detecting activated voxels. To compute the embedding, we build a graph of functionally connected voxels. We use the commute time, instead of the geodesic distance, to measure functional distances on the graph. Because the commute time can be computed directly from the eigenvectors of (a symmetric version) the graph probability transition matrix, we use these eigenvectors to embed the dataset in low dimensions. After clustering the datasets in low dimensions, coherent structures emerge that can be easily interpreted. We performed an extensive evaluation of our method comparing it to linear and nonlinear techniques using synthetic datasets and in vivo datasets. We analyzed datasets from the EBC competition obtained with subjects interacting in an urban virtual reality environment. Our exploratory approach is able to detect independently visual areas (V1/V2, V5/MT), auditory areas, and language areas. Our method can be used to analyze fMRI collected during “natural stimuli”.
Optical neural network: architecture, design, and models

An adaptive optical neuro network using inexpensive pocket size liquid crystal televisions (LCTVs) was recently developed by graduate students in the Electro-Optics Laboratory at The Pennsylvania State University. Although this neuro-computing has only 8 X 8 equals 64 neurons, it can be easily extended to 16 X 20 equals 320 neurons. The major advantages of this LCTV architecture as compared wither other ONCs, are low cost and flexibility to operate. To test the performance, several neural net models are used. These models are interpattern association, hetero-association, and unsupervised learning algorithms. The system design considerations and experimental demonstrations are also included.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Forward to the past: Historical preservation in globalizing Shanghai

This article examines the role of historical preservation in the spatial restructuring of postindustrial cities through a detailed case study of Xintiandi, a preservation–based redevelopment projec...
A Real Options Analysis of Coffee Planting in Vietnam

Vietnam grew from an insignificant to the world's second largest coffee producer during the 1990s. To understand this growth, this article examines Vietnamese coffee growers' investment decisions using real options theory. The study finds that producers, with variable costs of 19 cents/lb and total cost of 29.3 cents/lb, would enter coffee production at a coffee price of 47 cents/lb and exit at a coffee price of 14 cents/lb. Most Vietnamese growers appear to be sufficiently efficient to continue producing coffee even at relatively depressed price levels.
A Theory of the Nexus Supplier: A Critical Supplier From A Network Perspective

We introduce a new type of critical supplier�the nexus supplier�that becomes evident when we consider suppliers from a network perspective. The extant literature focuses on the importance of strategic suppliers and identifies strategic suppliers as critical due to their significant impact on a buying firm's profit and risk position. These strategic suppliers are considered one-at-a-time and tend to be top-tier suppliers. In contrast, a nexus supplier can come from anywhere in a multitier supply network and is critical due to its network position and the resultant portfolio of interorganizational ties. In this study, we offer a theory of the nexus supplier by integrating the supply management and social network literature. The theory is presented in the form of typologies, which articulate three ideal types of nexus suppliers and how they distinctively influence a focal buying firm's operational performance. We use real-world examples to build our arguments. We discuss implications of the nexus supplier for both theory and practice.
Combinatorial bounds on Hilbert functions of fat points in projective space

Abstract We study Hilbert functions of certain non-reduced schemes A supported at finite sets of points in P N , in particular, fat point schemes. We give combinatorially defined upper and lower bounds for the Hilbert function of A using nothing more than the multiplicities of the points and information about which subsets of the points are linearly dependent. When N = 2 , we give these bounds explicitly and we give a sufficient criterion for the upper and lower bounds to be equal. When this criterion is satisfied, we give both a simple formula for the Hilbert function and combinatorially defined upper and lower bounds on the graded Betti numbers for the ideal I A defining A , generalizing results of Geramita et al. (2006) [16] . We obtain the exact Hilbert functions and graded Betti numbers for many families of examples, interesting combinatorially, geometrically, and algebraically. Our method works in any characteristic.
Regulation of phenylethanolamine N-methyltransferase.

Publisher Summary This chapter discusses regulation of phenylethanolamine N -methyltransferase (PNMT). PNMT is localized almost exclusively to the adrenal medulla, although traces of activity have been reported in heart, brain, in extra-adrenal chromaffin tissue and in sympathetic ganglia. PNMT catalyzes the N -methylation of a number of primary and secondary β-hydroxyphenylethylamine derivatives. The requirement of the enzyme for β-hydroxylated phenylethylamine substrates appears to vary with species: PNMT from monkey, rabbit, rat and human with N -methylate only phenylethylamine substrates bearing a β-hydroxyl group. PNMTs from the rat and the frog share common substrate specificities, but virtually every other biochemical parameter of these enzymes differs. These include pH and thermal optima, thermal stability and starch-block migration. When these studies are compared with those of previous findings a striking uniformity of substrate specificity is observed, coupled with an equally striking heterogeneity of electrophoretic migration. These findings suggest that the evolution of PNMT has permitted amino acid substitutions which affect charge, molecular weight and stability of the enzyme, but has not tolerated alterations at the catalytic site of the molecule, which has remained relatively constant.
Giant Raman scattering by pyridine and CN− adsorbed on silver

The giant RS by pyridine and CN− on Ag is accompanied by a strong RS continuum which is attributed to inelastic light scattering by charge carrier-excitations. The enhanced RS by the adsorbed molecules and by the charge carrier-excitations are attributed to surface roughness enhanced EM fields at the metal surface resulting from the excitation of transverse collective electron-excitations and surface-EM modes, and to surface roughness-induced radiative-excitation and radiative-recombination of particle-hole pairs.
The Effects of the Mexican Corporate Governance Code on Quality of Earnings and its Components

The Corporate Governance Code (Code) was established in Mexico in January 2000 to increase investor confidence by encouraging more accurate financial reporting and more transparent disclosure practices by management. Using a sample of Mexican firms, we investigate whether or not there is an improvement in earnings quality surrounding the implementation date of the Code. We use a variety of earnings quality characteristics frequently studied in prior international research. Our results indicate that the quality of earnings increases after the implementation of the Code. While earnings quality characteristics generally improve for firms listed exclusively on the Mexican Bolsa, we only document improvements in income smoothing and timely loss recognition for Mexican firms listed on U.S. stock exchanges. Our results suggest that the filing jurisdiction of Mexican firms influences the impact we observe in changes in quality of earnings surrounding the implementation of the Mexican Corporate Governance Code.
Survey of the Bootes Void

Radial velocities have been measured for 231 galaxies chosen by apparent magnitude from 282 small fields spanning the area on the sky thought to contain the Bootes void. The galaxy distribution exhibits a spherical volume 6000 km/s in diameter in which no objects are found. The rms velocity difference of close pairs in our sample is less than 180 km/s.
A CFD Based Correlation for Erosion Factor for Long-Radius Elbows and Bends

A model for predicting sand erosion in 90 degree elbows and bends has been developed based on computational fluid dynamics (CFD), particle tracking and erosion data. After the flow field was obtained from the flow (CFD) model, particles were introduced into the flow and particle trajectories were computed using a Lagrangian approach. A model was also implemented that accounts for the interaction between the particles and the target material. Based on predicted particle impingement velocities, erosion rates and penetration rates were predicted using the empirical equations for erosion ratio. The predicted penetration rates are compared with available experimental data for several different elbows. The agreement between the predicted penetration rates and the experimental data is good. In addition, based on many predictions and erosion rate results, a new CFD based correlation is developed that can be used for an approximate engineering calculation to account for effects of elbow radius on erosion in long-radius elbows. This equation is for computing the ratio of the wall thickness loss (or the penetration rate) in a long-radius elbow to the penetration rate of a standard (short-radius) elbow. The results from the correlation agree well with the trend of available data in the literature.
Field-linked states of ultracold polar molecules

We explore the character of a novel set of 'field-linked' states that were predicted by Avdeenkov and Bohn [Phys. Rev. Lett. 90, 043006 (2003)]. These states exist at ultralow temperatures in the presence of an electrostatic field, and their properties are strongly dependent on the field's strength. We clarify the nature of these quasibound states by constructing their wave functions and determining their approximate quantum numbers. As the properties of field-linked states are strongly defined by anisotropic dipolar and Stark interactions, we construct adiabatic surfaces as functions of both the intermolecular distance and the angle that the intermolecular axis makes with the electric field. Within an adiabatic approximation we solve the two-dimensional Schroedinger equation to find bound states, whose energies correlate well with resonance features found in fully converged multichannel scattering calculations.
Whose will is it, anyway? A discussion of advance directives, personal identity, and consensus in medical ethics.

I consider objections to the use of living wills based upon the discontinuity of personal identity between the time of the execution of the directive anbd the time the person becomes incompetent. Recent authors, following Derek Parfit's “Complex View” of personal identity, have argued that there is often not sufficient identity interests between the competent person who executes the living will and the incompetent patient to warrant the use of the advance directive. I argue that such critics err by seeking personal identity in a purely descriptive manner. By exploring Buchanan and Brock's concept of “surviving interests”, an argument is developed that certain future-oriented acts have a normative force that contributes to the narrative unity which is constitutive of personal ideality. This narrative concept of the self is entailed by many of the our ordinary practices and challenges the philosophical consensus to view the self in a more dynamic and communitarian manner.
Effective slip boundary conditions for arbitrary periodic surfaces: the surface mobility tensor

In a variety of applications, most notably microfluidics design, slip-based boundary conditions have been sought to characterize fluid flow over patterned surfaces. We focus on laminar shear flows over surfaces with periodic height fluctuations and/or fluctuating Navier scalar slip properties. We derive a general formula for the ‘effective slip’, which describes equivalent fluid motion at the mean surface as depicted by the linear velocity profile that arises far from it. We show that the slip and the applied stress are related linearly through a tensorial mobility matrix, and the method of domain perturbation is then used to derive an approximate formula for the mobility law directly in terms of surface properties. The specific accuracy of the approximation is detailed, and the mobility relation is then utilized to address several questions, such as the determination of optimal surface shapes and the effect of random surface fluctuations on fluid slip.
An Investigation of the Loss of Planet-Forming Potential in Intermediate Sized Young Embedded Star Clusters

A large fraction of stars forming in our galaxy are born within clusters embedded in giant molecular clouds. In these environments, the background UV radiation fields impinging upon circumstellar disks can often dominate over the radiation fields produced by each disk's central star. As a result, this background radiation can drive the evaporation of circumstellar disks and lead to the loss of planet-forming potential within a cluster. This article presents a detailed analysis of this process for clusters whose stellar membership falls within the range of 100 ≤ N ≤ 1000. For these intermediate-sized clusters, the background UV field is often dominated by the most massive stellar member. Due to the steep slope of the initial mass function, the amount of background UV light that bathes clusters of similar size displays significant variance. As a result, we perform a statistical analysis of this problem by calculating distributions of FUV flux values impinging upon star/disk systems for several cluster scenarios. We find that in the absence of dust attenuation, giant planet formation would likely be inhibited in approximately half of the systems forming within intermediate-sized clusters, regardless of stellar membership. In contrast, the presence of dust can significantly lower this value, with the effect considerably more pronounced in more populated clusters.
Interprocedural Induction Variable Analysis

Induction variable analysis is an important part of the symbolic analysis in parallelizing compilers. Induction variables can be formed by for or loops within procedures or loops of recursive procedure calls. This paper presents an algorithm to find induction variables in formal parameters of procedures caused by recursive procedure calls. The compile-time knowledge of induction variables in formal parameters is essential to summarize array sections to be used for data dependence test and parallelization.
Carbonyl and olefin reactivities for the Baylis-Hillman reaction of fluorocarbonyls

The product formation and yields for the Baylis–Hillman reaction of fluorine-containing carbonyl compounds depend on a balance between the reactivities of the carbonyl and olefin partners.
Common database for tracker comparison

There are many different tracking methods and algorithms in development and use. It would be useful to compare these methods to determine which tracking algorithms are most appropriate for different situations. To make it possible to compare these methods a common database of input data has been set up. This database includes raw image sequences, filtered image sequences and detection lists. The data may be used by TBD and TAD trackers. The raw image sequences have been reprocessed to correct bad channels and remove pointing and stabilization errors and are available to the tracking community. Researchers are invited to make use of this data nd present their results. This paper describes the database, how to access it and the results of using the Multiple Hypotheses Tracking algorithm on the image sequences contained within. A description of the signal processing used on the images and the MHT algorithm will also be included.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Excitation of Alfven waves by high-energy ions in a tokamak

It is shown that shear Alfv\'en waves can be destabilized by resonance with high-energy "beam" ions near the magnetic axis in a tokamak, if the beam is radially nonuniform.
New approaches for high-yield purification of Müllerian inhibiting substance improve its bioactivity

Abstract We have established a new method to purify Mullerian inhibiting substance (MIS) with higher purity and recovery over existing procedures. Recombinant human MIS was expressed in Chinese hamster ovary cells and secreted into chemically defined serum-free media. The secreted products were concentrated by either precipitation with ammonium sulfate or lectin-affinity chromatography, each of which was followed by anion-exchange chromatography. Further separation of the active carboxy-terminal domain of MIS was achieved after cleavage by plasmin followed by lectin-affinity chromatography. This method may be applicable to other members of the transforming growth factor β family with which MIS shares sequence homology.
Structure-activity relationships of a series of benzothiophene-derived NPY Y1 antagonists: optimization of the C-2 side chain.

Abstract A series of benzo[ b ]thiophene-derived NPY-1 receptor antagonists is described. Systematic modification of the C-2 substituent afforded a 1000-fold range in Y1 receptor affinity. Appropriate substitution at the ortho and para positions of the C-2 phenyl ether produced a synergistic effect on Y1 binding affinity, which led to the discovery of the most active ligands, 12t (K i = 15 nM), 12u (K i = 11 nM), and 12v (K i = 13 nM).
Emotional reactions to having cancer.

Much discussion of the management of patients with cancer centers on what to tell the patient about his diagnosis. The more basic issue of what the patient already knows has not often been considered.Fifty patients were interviewed by a psychiatrist as they registered for treatment at the Radiotherapy Center of the Mount Sinai Hospital in New York. All had cancer. Forty (80 per cent) correctly gave their own diagnosis.These 40 patients were not told of their diagnosis by their physicians. How they learned they had cancer and how they reacted to that knowledge was the focus of this study.The degree of anxiety and depression in these patients was the basis for discussion of what helped them to function. A series of mechanisms of defense was found to be in use. None of these patients had attempted suicide, despite knowledge that they had cancer.The interrelationship of neuroses existing prior to the diagnosis of cancer, with emotional reactions to that diagnosis, was noted in 7 patients. Only 1 subject devel...
Simplified description of slow-in-the-average Markov walks

Abstract The averaging theory for the slow Markov walks is extended to the so called slow-in-the-average Markov processes where the jump vector takes arbitrarily large values with sufficiently small probabilities. The results obtained are important for applications, in particular, communication networks and manufacturing systems.
Fictitious flux confinement: Magnetic pairing in coupled spin chains or planes

The spinon and holon excitations of two-leg Heisenberg or lightly doped $t\ensuremath{-}J$ ladders are shown to be bound in pairs by string confinement forces given approximately by the antiferromagnetic exchange energy across the rungs, ${F=J}_{\ensuremath{\perp}}〈{\mathbf{S}}_{i}{\mathbf{S}}_{j}{〉}_{\ensuremath{\perp}}/b.$ These forces originate from fictitious flux tubes associated with the half-Fermi statistics of the excitations. It is conjectured that similar confinement forces, determined by the antiferromagnetic exchange energy across the layers, are partially responsible for the spin gap and the pairing of charge carriers in multilayer CuO superconductors.
Octahedral Niobium Chloride Clusters as Building Blocks of Templated Prussian Blue Framework Analogues

The preparation, structure, and magnetic properties of the first three-dimensional framework containing octahedral niobium cyanochloride clusters as building units are reported. Reactions of aqueous solutions of (Me4N)2K2[Nb6Cl12(CN)6] (2) with aqueous solutions of MnCl2 result in the precipitation of the compound (Me4N)2[MnNb6Cl12(CN)6] (3). The structure of 3 was determined from single-crystal X-ray diffraction study (crystal data: cubic, Fm3m (No. 225), a = 15.513(4) A, V = 3733.2(12) A3, Z = 4). Its 3D framework is based on edge-bridged [Nb6Cl12]2+ clusters and Mn2+ ions bridged by cyanide ligands to form a cfc lattice [MnNb6Cl12(CN)6]2- in which all tetrahedral sites are occupied by the cations (Me4N)+ which act as charge compensating template. The structure of 3 can be considered as an expansion of the Prussian blue framework in which [Fe(CN)6]4- is replaced by the cluster [Nb6Cl12(CN)6]4-. Magnetic susceptibility measurements indicate that Mn2+ is present in a high spin d5 configuration. No magne...
D0-BRANES IN GEPNER MODELS AND N = 2 BLACK HOLES

Abstract In this paper D-brane boundary states constructed in Gepner models are used to analyze some aspects of the dynamics of DO-branes in Calabi-Yau compactifications of type II theories to four dimensions. It is shown that the boundary states correspond to BPS objects carrying dyonic charges. By analyzing the couplings to closed string fields a correspondence between the DO-branes and extremal charged black holes in N = 2 supergravity is found.
Homeomorphisms of the 3-sphere that preserve a Heegaard splitting of genus two

Let H 2 be the group of isotopy classes of orientation-preserving homeomorphisms of S 3 that preserve a Heegaard splitting of genus two. In this paper, we construct a tree in the barycentric subdivision of the disk complex of a handlebody of the splitting to obtain a finite presentation of H 2 .
Pd(II)-catalyzed ortho trifluoromethylation of arenes and insights into the coordination mode of acidic amide directing groups.

A Pd(II)-catalyzed trifluoromethylation of ortho C–H bonds with an array of N-arylbenzamides derived from benzoic acids is reported. N-Methylformamide has been identified as a crucial promoter of C–CF3 bond formation from the Pd center. X-ray characterization of the C–H insertion intermediate has revealed a rare coordination mode of acidic amides as directing groups and the origin of their capacity in directing C–H activation.
Computational geometry column 40

It has recently been established by Below, De Loera, and Richter-Gebert that finding a minimum size (or even just a small) triangulation of a convex polyhedron is NP-complete. Their 3SAT-reduction proof is discussed.
Nucleotide Intermediates in the Biosynthesis of Polysaccharides

In metabolism, nucleotides play a roLe not only as the procursors of nucleic acids. Many low molecular weight compounds may be activated for subsequent biosysthesis by forming anhydrides or esters with nucletides. These nucleotide derivatives functions as carriers of the residues attached to them. Frequently the residues become chemically changed while a attched to the nucleotide before transfer in a biosynthetic reaction. Following a general survey of nucleotide-types, and their reaction, into the biosynthesis of sulfated polysaccharides is described.
Efficient and realistic device modeling from atomic detail to the nanoscale

As semiconductor devices scale to new dimensions, the materials and designs become more dependent on atomic details. NEMO5 is a nanoelectronics modeling package designed for comprehending the critical multi-scale, multi-physics phenomena through efficient computational approaches and quantitatively modeling new generations of nanoelectronic devices as well as predicting novel device architectures and phenomena. This article seeks to provide updates on the current status of the tool and new functionality, including advances in quantum transport simulations and with materials such as metals, topological insulators, and piezoelectrics.
Selective Surface Roughness to Suppress Flow-Induced Motion of Two Circular Cylinders at 30,000 < Re < 120,000

In the Marine Renewable Energy Laboratory of the University of Michigan, selectively located surface roughness has been designed successfully to suppress vortex-induced vibrations of a single cylinder by 60% compared to a smooth cylinder. In this paper, suppression of flow-induced motions of two cylinders in tandem using surface roughness is studied experimentally by varying flow velocity and cylinder center-to-center spacing. The two identical cylinders are rigid, suspended by springs, and allowed to move transversely to the flow direction and their own axis. Surface roughness is applied in the form of four roughness strips helically placed around the cylinder. Results are compared to smooth cylinders also tested in this work. Amplitude ratio A/D, frequency ratio fosc/fn,water, and range of synchronization are measured. Regardless of the center-to-center cylinder distance, the amplitude response of the upstream smooth-cylinder is similar to that of the isolated smooth-cylinder. The wake from the upstream cylinder with roughness is narrower and longer and has significant influence on the amplitude of the downstream cylinder. The latter is reduced in the initial and upper branches while its range of VIV-synchronization is extended. In addition the amplitude of the upstream rough cylinder and its range of synchronization increase with respect to the isolated rough cylinder.Copyright © 2013 by ASME