cssi/SciSciGPT-SciSciNet huggingface dataset:
The extraction of community structures from publication networks to support ethnographic observations of field differences in scientific communication

The scientific community of researchers in a research specialty is an important unit of analysis for understanding the field specific shaping of scientific communication practices. These scientific communities are, however, a challenging unit of analysis to capture and compare because they overlap, have fuzzy boundaries, and evolve over time. We describe a network analytic approach that reveals the complexities of these communities through examination of their publication networks in combination with insights from ethnographic field studies. We suggest that the structures revealed indicate overlapping sub-communities within a research specialty and we provide evidence that they differ in disciplinary orientation and research practices. By mapping the community structures of scientific fields we aim to increase confidence about the domain of validity of ethnographic observations as well as of collaborative patterns extracted from publication networks thereby enabling the systematic study of field differences. The network analytic methods presented include methods to optimize the delineation of a bibliographic data set in order to adequately represent a research specialty, and methods to extract community structures from this data. We demonstrate the application of these methods in a case study of two research specialties in the physical and chemical sciences. *: Corresponding author This article introduces a method for the analysis of scientific publication networks that supports ethnographic observations of field differences in scientific communication. This work is part of a larger research program to develop a mixed method approach that combines qualitative-ethnographic and quantitative-network analytic methods to systematically study and develop theoretical explanations for differences of scientific communication practices across research specialties. The emergence of the World Wide Web and adoption of web based technologies to support scientific communication has revived research interest into field differences in scientific communication practices (Kling & Kim 2000, Fry & Talja 2007). However, comparative studies of scientific fields with an ethnographic depth of understanding of research practices and social behaviors are rare (Glaser 2006), and bibliometric studies provide only narrow insights into field specific practices because of the limitations of publication data to reflect underlying research and communication processes (Lievrouw 1990). The current scarcity of empirical material comparing scientific communities at the field level inhibits theory development to answer fundamental questions such as how field-specific characteristics of scientific knowledge interact with the social ordering of scientific communities (Glaser 2006), and how epistemic cultures shape communication practices (Cronin 2003, Fry & Talja 2004) and attitudes towards openness and sharing (Velden 2011a). To advance research on these questions, we propose to bridge the methodological gap with an
Mammography Adherence in African-American Women: Results of a Randomized Controlled Trial

Breast cancer is the second leading cause of cancer mortality among women in the developed world. Mammography screening is especially important for African-Americans because they experience a greater mortality (OR = 1.38) than Caucasians despite having a lower incidence of breast cancer. The purpose of this study was to compare the effects of two interventions with usual care on mammography adherence among African-American women. A subsample of African-American women (n = 244) aged 41–65 years who had not had a mammogram in the last 15 months and no history of breast cancer was randomly assigned to receive (1) mailed interactive DVD, (2) computer-tailored telephone counseling, or (3) usual care. The DVD intervention was five times more effective than usual care for promoting mammography screening at 6 months follow-up among women who earned less than $30,000 (OR = 5.3). Compared to usual care, neither the DVD nor phone produced significant effects for women with household incomes >$30,000. Use of a mailed DVD for low-income African-American women may be an effective way to increase mammography adherence.
High Resolution X-Ray Spectroscopy from the Einstein Observatory

This paper is devoted to a discussion of some results which we have recently obtained from the fourth of the principal instruments on board the Einstein Observatory: M.I.T.’s Focal Plane Crystal Spectrometer (FPCS). We shall begin with a few general remarks about X-ray spectroscopy, followed by a brief description of the FPCS instrument. The results we present here deal primarily with supernova remnants (SNRs): Puppis A and Cas A in the Galaxy, and N132D and N63A in the Large Magellanic Cloud. In addition we shall briefly discuss a member of the other class of thermal X-ray source under discussion at present; namely, to report our detection of oxygen emission from the vicinity of M87 in the Virgo Cluster.
Prediction and description of a chiral pseudogap phase

We point out that a system which supports chiral superconductivity should also support a chiral pseudogap phase: a finite temperature phase wherein superconductivity is lost but time-reversal symmetry is still broken. This chiral pseudogap phase can be viewed as a state with phase incoherent Cooper pairs of a definite angular momentum. This physical picture suggests that the chiral pseudogap phase should have definite magnetization, should exhibit a (nonquantized) charge Hall effect, and should possess protected edge states that lead to a quantized thermal Hall response. We explain how these phenomena are realized in a Ginzburg-Landau description, and comment on the experimental signatures of the chiral pseudogap phase. We expect this work to be relevant for all systems that exhibit chiral superconductivity, including doped graphene and strontium ruthenate.
D-log and formal flow for analytic isomorphisms of n-space

Given a formal map F = (F1 . . . , Fn) of the form z + higher order terms, we give tree expansion formulas and as- sociated algorithms for the D-Log of F and the formal flow Ft. The coefficients which appear in these formulas can be viewed as certain generalizations of the Bernoulli numbers and the Bernoulli polynomials. Moreover the coefficient polynomials in the formal flow formula coincide with the strict order polynomials in combina- torics for the partially ordered sets induced by trees. Applications of these formulas to the Jacobian Conjecture are discussed.
The mathematical theory of molecular motor movement and chemomechanical energy transduction

The mathematical formulation of the model for molecular movement of single motor proteins driven by cyclic biochemical reactions in an aqueous environment leads to a drifted Brownian motion characterized by coupled diffusion equations. In this article, we introduce the basic notion for the continuous model and review some asymptotic solutions for the problem. (For the lattice model see [17,47].) Stochastic, non-equilibrium thermodynamic interpretations of the mathematical equations and their solutions are presented. Some relevant mathematics, mainly in the field of stochastic processes, are discussed.
Chapter 2 – Technical Background

This chapter discusses general techniques, technical issues, and animation techniques presented in the remaining chapters. The chapter is divided into two sections. The first section serves as a quick review of the basics of computer graphics display pipeline and discusses the control of round-off error when data is repeatedly transformed. It is understood that readers know in advance about transformation matrices, homogeneous coordinates, and the display pipeline, including the perspective transformation. The second section deals with numerous orientation representations and quaternion arithmetic, which is important for the discussion of orientation interpolation. There are several orientation representations to choose from. The most robust representation of orientation is quaternion, but fixed angle, Euler angle, and axis angle are more intuitive, easier to implement, and often sufficient for a given situation. A detailed section on quaternion representation of orientation is presented in this chapter as well. If the reader is well versed in computer graphics, this chapter may be skimmed to pick up relevant terminology or skipped altogether.
Lunar impact basins: Stratigraphy, sequence and ages from superposed impact crater populations measured from Lunar Orbiter Laser Altimeter (LOLA) data

[1] Impact basin formation is a fundamental process in the evolution of the Moon and records the history of impactors in the early solar system. In order to assess the stratigraphy, sequence, and ages of impact basins and the impactor population as a function of time, we have used topography from the Lunar Orbiter Laser Altimeter (LOLA) on the Lunar Reconnaissance Orbiter (LRO) to measure the superposed impact crater size-frequency distributions for 30 lunar basins (D ≥ 300 km). These data generally support the widely used Wilhelms sequence of lunar basins, although we find significantly higher densities of superposed craters on many lunar basins than derived by Wilhelms (50% higher densities). Our data also provide new insight into the timing of the transition between distinct crater populations characteristic of ancient and young lunar terrains. The transition from a lunar impact flux dominated by Population 1 to Population 2 occurred before the mid-Nectarian. This is before the end of the period of rapid cratering, and potentially before the end of the hypothesized Late Heavy Bombardment. LOLA-derived crater densities also suggest that many Pre-Nectarian basins, such as South Pole-Aitken, have been cratered to saturation equilibrium. Finally, both crater counts and stratigraphic observations based on LOLA data are applicable to specific basin stratigraphic problems of interest; for example, using these data, we suggest that Serenitatis is older than Nectaris, and Humboldtianum is younger than Crisium. Sample return missions to specific basins can anchor these measurements to a Pre-Imbrian absolute chronology.
A Knowledge-Based Cohesion Metric for Object-Oriented Software

This paper presents Percentage of Shared Ideas (PSI), a metric for measuring the semantic cohesion of a class in object-oriented software. PSI uses information in a knowledge base to quantify the cohesiveness of a class’s task in the problem domain, allowing a clearer view of cohesion than code syntax provides. Furthermore, this metric is independent of code structure and could be calculated before implementation, providing clues to design flaws earlier in the software development cycle, when changes are less expensive. In this paper, we define the PSI metric, provide theoretical and empirical validation, and compare PSI to well-known cohesion metrics.
The Growing Importance of Social Skills in the Labor Market

The labor market increasingly rewards social skills. Between 1980 and 2012, jobs requiring high levels of social interaction grew by nearly 12 percentage points as a share of the U.S. labor force. Math-intensive but less social jobs—including many STEM occupations—shrank by 3.3 percentage points over the same period. Employment and wage growth were particularly strong for jobs requiring high levels of both math skill and social skills. To understand these patterns, I develop a model of team production where workers “trade tasks” to exploit their comparative advantage. In the model, social skills reduce coordination costs, allowing workers to specialize and work together more efficiently. The model generates predictions about sorting and the relative returns to skill across occupations, which I investigate using data from the NLSY79 and the NLSY97. Using a comparable set of skill measures and covariates across survey waves, I find that the labor market return to social skills was much greater in the 2000s than in the mid-1980s and 1990s.
Simultaneous Identification of Neutral and Anionic Species in Complex Mixtures without Separation

A chemosensory system is reported that operates without the need for separation techniques and is capable of identifying anions and structurally similar bioactive molecules. In this strategy, the coordination of analytes to a metal complex with an open binding cleft generates "static structures" on the NMR timescale. Unique signals are created by strategically placing fluorine atoms in close proximity to bound analytes so that small structural differences induce distinct (19)F NMR shifts that can be used to identify each analyte. The utility of this method is illustrated by quantifying caffeine levels in coffee, by identifying ingredients in tea and energy drinks, and by discriminating between multiple biogenic amines with remote structural differences six carbon atoms away from the binding site. We further demonstrate the simultaneous identification of multiple neutral and anionic species in a complex mixture.
Birth Rates and Border Crossings: Latin American Migration to the US, Canada, Spain and the UK*

We use census data for the US, Canada, Spain and UK to estimate bilateral migration rates to these countries from 25 Latin American and Caribbean nations over the period 1980 to 2005. Latin American migration to the US is responsive to labour supply and demand shocks as well as natural disasters. Latin American migration to Canada, Spain and the UK, in contrast, is largely insensitive to these shocks, responding only to civil and military conflict. The results are consistent with US immigration being mediated by market forces and immigration to the other countries being insulated from labour market shocks.
Real-Time Sonographic Sector Scanning of the Neonatal Cranium: Technique and Normal Anatomy

A commercially available wide field of view real-time mechanical sector scanner can be used to image the neonatal cranium. Because of the small transducer head size, the open anterior fontanelle can function as an acoustic window. By thus avoiding bone, higher frequency transducers may be used to improve image resolution. Infants may be scanned quickly without sedation in their isolettes in the neonatal intensive care unit. Sterility of the infant environment is maintained by placing the transducer in a surgical glove. Using this technique, detailed normal anatomy can be seen such as vascular structures, caudate nucleus, thalamus, third ventricle, cavum septum pellucidum, and the thalamocaudate notch. Angled coronal and sagittal sonographic anatomy is correlated with neonatal cadaver brain sections sliced in similar planes centered on the anterior fontanelle.
BREAST CANCER AND ORAL CONTRACEPTIVE USE

The risk of breast cancer in relation to oral contraceptive use was evaluated in a case-control study of 1191 patients with breast cancer and 5026 control patients. For ever-use compared with never-use, the estimated relative risk of breast cancer was 1.0 (95% confidence interval 0.9-1.2). Use of oral contraceptives for five or more years was not associated with breast cancer, regardless of whether use had ended as much as 10 or more years previously, or more recently. Within categories of women whose baseline risk was elevated, including nulligravidae, premenopausal women, and those with benign breast disease or history of breast cancer in first-degree relatives, the relative risk estimates for five or more years of oral contraceptive use approximated 1.0. For any use before first pregnancy, the relative risk estimate was 1.3, and for use lasting three or more years it was 0.9. These data suggest that long-term oral contraceptive use does not increase the risk of breast cancer even after a latent interval in excess of one decade; nor do oral contraceptives appear to increase the risk within categories of women at relatively high baseline risk.
One‐Pot Preparation of Enantiopure Fluorinated β‐Amino Acid Precursors

Chiral β-fluoro amines and β,β-difluoro amines are common substructures in medicinal compounds. Industrial syntheses typically use enantiopure starting materials, chiral auxiliaries, or the resolution of enantiomeric or diastereomeric mixtures to install these functionalities in enantiopure form. With the goal of improving access to these substructures, we recently developed the first catalytic enantioselective olefin aminohalogenation reaction, which produced chiral β-fluoro amines in a single flask from achiral enal starting materials. This paper describes the extension of this method to the preparation of β-amino-α,α-difluoro carbonyl compounds. Specifically, carbon–nitrogen and carbon–fluorine bond-forming reactions were combined in an organocascade reaction to produce β-amino-α,α-difluoro carbonyl compounds containing alkyl substituents at the β-position. As such, this method is mechanistically distinct from, and complementary to, existing one-pot catalytic enantioselective methods for the preparation of fluorinated β-amino acid precursors.
Tunable microdoublet lens array

We report a tunable microdoublet lens capable of creating dual modes of biconvex or meniscus lens. The microdoublet lens consists of a tunable liquid-filled lens and a solid negative lens. It can be tuned either by changing the shape of the liquid-filled lens into biconvex or meniscus or by changing a filling media with different refractive index. The microfabrication is based on photopolymer microdispensing and elastomer micromolding methods. The microdoublet lens can provide a solution for minimizing optical aberrations and maximizing the tunability of focal length or field of view by controlling variable and fixed lens curvatures.
TEORIA DA BIBLIOTECA 2.0: Web 2.0 e suas implicações para as bibliotecas

Este artigo firma uma definicao e uma teoria para “Biblioteca 2.0”. Ele sugere que o pensamento recente sobre a mudanca da Web como “Web 2.0” tera implicacoes substanciais para as bibliotecas, e reconhece que enquanto essas implicacoes mantiverem-se proximas da historia e da missao das bibliotecas, elas ainda necessitarao de um novo paradigma para a biblioteconomia. O artigo aplica a teoria e a definicao para a pratica da biblioteconomia, especificamente discutindo como as tecnologias Web 2.0, como mensagens sincronas e streaming media, blogs, wikis, redes sociais, tagging, alimentadores RSS, e mashups podem forcar mudancas no modo como as bibliotecas oferecem acesso a suas colecoes e o suporte ao usuario para tal acesso.
Representation policy iteration

This paper addresses a fundamental issue central to approximation methods for solving large Markov decision processes (MDPs): how to automatically learn the underlying representation for value function approximation? A novel theoretically rigorous framework is proposed that automatically generates geometrically customized orthonormal sets of basis functions, which can be used with any approximate MDP solver like least-squares policy iteration (LSPI). The key innovation is a coordinate-free representation of value functions, using the theory of smooth functions on a Riemannian manifold. Hodge theory yields a constructive method for generating basis functions for approximating value functions based on the eigenfunctions of the self-adjoint (Laplace-Beltrami) operator on manifolds. In effect, this approach performs a global Fourier analysis on the state space graph to approximate value functions, where the basis functions reflect the large-scale topology of the underlying state space. A new class of algorithms called Representation Policy Iteration (RPI) are presented that automatically learn both basis functions and approximately optimal policies. Illustrative experiments compare the performance of RPI with that of LSPI using two handcoded basis functions (RBF and polynomial state encodings).
Apoptosis in leukoaraiosis.

We report a case of leukoaraiosis that was studied for apoptosis. In the neuropil, the number of cells that showed DNA fragmentation was 2.5 times as great in the area of leukoaraiosis as in the adjacent white matter (P = .004) and 25 times as great as in the nearby cortex (P < .001). Our findings suggest that apoptosis, predominantly of oligodendrocytes, is involved in the pathogenesis of leukoaraiosis. Within the area of leukoaraiosis, we also found numerous small veins that were partially occluded by severe collagenous thickening of the vessel walls. This collagenosis may have contributed to or resulted from chronic ischemia in that area.
The Axisymmetric Crack Problem in a Nonhomogeneous Medium

Abstract : In this paper the axisymmetric crack problem for a nonhomogeneous medium is considered. It is assumed that the shear modulus is a function of z approximated by mu = mu (sub 0) e to the alpha z power. This is a simple simulation of materials and interfacial zones with intentionally or naturally graded properties. The problem is a mixed mode problem and is formulated in terms of a pair of singular integral equations. With fracture mechanics applications in mind, the main results given are the stress intensity factors as a functions of the nonhomogeneity parameter alpha for various loading conditions. Also given are some sample results showing the crack opening displacements.
A Short Proof of the Simple Continued Fraction Expansion of e

(2006). A Short Proof of the Simple Continued Fraction Expansion of e. The American Mathematical Monthly: Vol. 113, No. 1, pp. 57-62.
CEO Compensation and Stakeholders' Claims*

The traditional view that a corporation exists solely to serve the interests of the firm's shareholders has given way to a changing view that recognizes the importance of corporate constituents in addition to shareholders. Prior studies demonstrate a significant association between the sensitivity of CEO compensation and a firm's stock prices. However, the association between CEO compensation and the claim of other primary stakeholders (customers, employees, suppliers) has not been examined. The purpose of this study is to investigate whether the adoption of long-term incentive plans aligns the interest of the CEO with the interest of the primary stakeholders in the firm. Using the fixed-effect regression, our results indicate a significant association between the change in CEO compensation and the claims of the customers, shareholders, and employees. We contribute to the literature by demonstrating that the managers are accountable not only to the shareholders but also to primary stakeholders.
AGGREGATION OVER FIRMS AND FLEXIBLE FUNCTIONAL FORMS

This paper presents a generalized class of cost functions suitable for aggregation of firms and considers various flexible functional forms to assess whether they possess desirable aggregation properties. This set of cost functions includes two output functions and subsumes linear and nonlinear cost functions employed in existing analyses. While the quadratic and the generalized Leontief and McFadden cost functions satisfy the generalized aggregation condition, the translog cost function and its variants are less capable of possessing desirable aggregation properties. A modified quasi-homothetic translog form is presented that is useful for aggregate analysis. Possible extensions of the generalized aggregation rule are discussed.
Self-Similar Fluid-Dynamic Limits for the Broadwell System

This report discusses a new approach for the resolution of the fluid-dynamic limit for the Broadwell system of the kinetic theory of gases, appropriate in the case of Riemann, Maxwellian data. Since the formal limiting system is expected to have self-similar solutions, we are motivated to replace the Knudsen number ɛ in the Broadwell model so that the resulting model admits self-similar solutions ξ=x/t and then let ɛ go to zero. The limiting procedure is justified and the resulting limit is a solution of the Riemann problem for the fluid-dynamic limit equations. A class of Riemann data for which this program can be carried out is exhibited. Furthermore, it is shown that for the Carleman model the complete program can be done successfully for arbitrary Riemann data.
The classification of Kleinian surface groups, I: models and bounds

We give the first part of a proof of Thurston’s Ending Lamination conjecture. In this part we show how to construct from the end invariants of a Kleinian surface group a “Lipschitz model” for the thick part of the corresponding hyperbolic manifold. This enables us to describe the topological structure of the thick part, and to give a priori geometric bounds.
Catalytic Asymmetric Oxidation of tert-Butyl Disulfide. Synthesis of tert-Butanesulfinamides, tert-Butyl Sulfoxides, and tert-Butanesulfinimines

The first example of the catalytic asymmetric oxidation of tert-butyl disulfide (1) is described. The product, tert-butyl tert-butanethiosulfinate (2) is obtained with 91% enantiomeric excess in yields of ≥92% on scales as large as 1 mol. The application of H2O2 as stoichiometric oxidant in the presence of 0.25 mol % of VO(acac)2 and 0.26 mol % of a chiral Schiff base ligand, 6a, is both convenient and cost-effective. Thiosulfinate ester 2 is chemically and optically stable and serves as an excellent precursor to chiral tert-butanesulfinyl compounds by the stereospecific nucleophilic displacement of tert-butyl thiolate. Addition of LiNH2 in liquid ammonia and THF provides tert-butanesulfinamide (3; 91% yield). A single recrystallization provides enantiomerically pure 3 in 71−75% overall yield from disulfide 1. Enantiomerically pure thiosulfinate ester 2 also reacts readily and stereospecifically with Grignard reagents, organolithiums, lithium amides, and lithium imine salts to provide enantiomerically pur...
A model for designing adaptable software components

An important aim of software engineering is to produce reliable and robust software systems. As software systems grow in size, however, it becomes infeasible to design and construct software systems from scratch. Most software developers are familiar with reusing code from component libraries to speed up tedious programming tasks, such as constructing graphical user interfaces. However, it is still an elusive goal to construct applications entirely from pre-existing, independently developed components. We believe that such component-based development will only occur when application builders can adapt software components to suit their needs.The goal of this research is to develop novel techniques for designing software components that provide a mechanism for adapting their behavior. We aim to achieve higher levels of component use/reuse than existing approaches for reusing software components. The Active Interface technique we propose enables software components to provide two interfaces --- one for behavior and one for adapting that behavior as needed.We make a distinction between software evolution, where the component designer modifies the software component, and adaptation, where an application builder adapts the component for a different use. We also differentiate adaptation from customization; an end-user customizes a software component by choosing from a fixed set of options. An end-user adapts a software component by writing new code to alter existing functionality.
Virtual Impedance Current Limiting for Inverters in Microgrids With Synchronous Generators

This paper focuses on current limiting for voltage-controlled inverters during overloads caused by poor transient load sharing between inverters and synchronous generators in islanded microgrids. The use of simple current reference saturation limiters can cause instability when the voltage regulator loses control after the current reference saturates. The use of virtual impedance for current limiting is shown to improve transient stability during current limiting when operating in parallel with synchronous generators. Small-signal analysis is used to set the virtual impedance magnitude and $X/R$ ratio, and validation is provided by simulation and experimental results.
An order-reversing duality map for conjugacy classes in Lusztig's canonical quotient

We define a partial order on the set No,c of pairs (O,C), where O is a nilpotent orbit and C is a conjugacy class in A(O), Lusztig’s canonical quotient of A(O). We then show that there is a unique order-reversing duality map No,c → LNo,c that has certain properties analogous to those of the original Lusztig–Spaltenstein duality map. This generalizes work of E. Sommers.
Absence of reflection as a function of the coupling constant

We consider solutions of the one-dimensional equation −u″+(Q+λV)u=0 where Q:R→R is locally integrable, V:R→R is integrable with supp(V)⊂[0,1], and λ∊R is a coupling constant. Given a family of solutions {uλ}λ∊R which satisfy uλ(x)=u0(x) for all x<0, we prove that the zeros of b(λ)≔W[u0,uλ], the Wronskian of u0 and uλ, form a discrete set unless V≡0. Setting Q(x)≔−E, one sees that a particular consequence of this result may be stated as: if the fixed energy scattering experiment −u″+λVu=Eu gives rise to a reflection coefficient which vanishes on a set of couplings with an accumulation point, then V≡0.
Sodium Diffusion in Sodium Aluminophosphate Glasses

Mesure d'environ 170°C a presque la temperature de transition vitreuse de l'autodiffusion des ions sodium dans les verres xAl 2 O 3 (100-x) Na 2 P 2 O 6 (2,44≤x≤25,92 mol%) quand la concentration en Al 2 O 3 augmente, le coefficient de diffusion du sodium decroit seulement d'un facteur de 2 a 3
Real-time implementation of order-statistics-based directional filters

Vector filters based on order-statistics have proved successful in removing impulsive noise from colour images while preserving edges and fine image details. Among these filters, the ones that involve the cosine distance function (directional filters) have particularly high computational requirements, which limits their use in time-critical applications. In this paper, we introduce two methods to speed up these filters. Experiments on a diverse set of colour images show that the proposed methods provide substantial computational gains without significant loss of accuracy.
Streamwise Vortex Instability and Transition on the Hyper-2000 Scramjet Forebody

Despite the closely coupled multidisciplinary design of hypersonic airbreathing vehicles, the boundary layer transition mechanisms that are important on the forebody ahead of the scramjet inlet are not well understood. The present paper investigates transition induced by the growth of streamwise vortices on a scramjet forebody geometry similar to the Hyper- X. Characteristics of the separation zone near the first compression corner are visualized with oil-flow experiments. These experiments also reveal the presence of regularly spaced streamwise vortices on the compression ramp even in the absence of controlled disturbance generators. The growth and decay of these vortices are inferred from the heat-transfer rates measured using temperature-sensitive-paints. The streamwise vortices are enhanced in a controlled and repeatable manner by wrapping tapes around the leading edge. The vortices grow significantly on the second compression ramp and then decay, suggesting transition onset. The disturbance growth seems to show a systematic trend with unit Reynolds number, although this trend was not consistently seen for all cases. For some of the cases, the disturbances showed the largest growth when the roughness spacing was close to the vortex spacing seen in the oil-flow images.
Antimicrobial Peptides in Toroidal and Cylindrical Pores

Antimicrobial peptides (AMPs) are small, usually cationic peptides, which permeabilize biological membranes. Understanding their mechanism of action might help design better antibiotics. Using molecular dynamics (MD) simulations, we investigate the preference of alamethicin and melittin for pores of different shapes. In the simulations, an alamethicin hexamer initially embedded in a pre-formed cylindrical pore preserves the pore shape or closes the pore if glutamines in the N-terminus are not located within the pore. On the other hand, when a melittin tetramer is embedded in a toroidal pore or in a cylindrical pore, at the end of the simulations the pore is lined both with peptides and lipid headgroups, and, thus, can be classified as a toroidal pore. These observations agree with the prevailing views that alamethicin forms barrel-stave pores whereas melittin forms toroidal pores. The melittin tetramer interacts more strongly with lipids in the toroidal pore than in the cylindrical one, due to more favorable electrostatic interactions. Using an implicit membrane model, modified to include pores of different shapes, we show that melittin is better solvated in toroidal pores than in cylindrical ones.
Fast, Radiation‐Hard Scintillating Detector: A Potential Application for Sol‐Gel Glass

To meet the present-day rate and radiation dose requirements, one would like to have a scintillator with the high radiation resistance of pure silica glass and the short fluorescence decay time of organic fluors. The new technology of sol-gel glass production permits the preparation of organic/inorganic composite materials by doping the silica gels with organic fluors. The procedure of production of monolithic organic/inorganic composite materials, such as 2-(4-tertbutylphenyl)-5-(4-biphenylyl)-1,3,4-oxadiazole/SiO2, p-terphenyl/SiO2, p-quaterphenyl/SiO2, and 3-hydroxyflavone/SiO2, and the associated characterization techniques are described. The efficiency of light production, the light attenuation, the time width of light pulse, and the radiation resistance of the scintillating sol-gel glass are discussed. Preliminary results indicate that this technical advance will permit the creation of new materials with potential application such as particle detectors which are both radiation hard and fast.
Adding a brane to the brane anti-brane action in BSFT

We attempt to generalize the effective action for the D-brane-anti-D-brane system obtained from boundary superstring field theory (BSFT) by adding an extra D-brane to it to obtain a covariantized action for 2 D-branes and 1 anti-D-brane. We discuss the approximations made to obtain the effective action in closed form. Among other properties, this effective action admits solitonic solutions of codimension 2 (vortices) when one of the D-brane is far separated from the brane-anti-brane pair.
High-energy bremsstrahlung from proton-nucleus collisions

Abstract Theoretical calculations are described and numerical results given for the production of high-energy bremsstrahlung from proton bombardment of light nuclei. The results are compared with experiment. The Born approximation is used. The parameters in a square well potential with exchange forces and a repulsive core are set up to agree with experimental neutron-proton scattering, also calculated by Born approximation. The exclusion principle is taken into account by excluding final states — or permitting them — in accordance with the fraction of phase space occupancy of the assumed momentum distribution. A notable feature is the strong dependence of the radiation cross-section on the assumed momentum distribution. A best fitting momentum distribution with a mean kinetic energy of 32 MeV is deduced for the neutrons in beryllium. The model used assumes proton-neutron interactions as a radiation source. Some calculations for a proton-nucleus interaction are given. These do not fit experimental data at all well.
Measuring Customer Relationship Value: The Role of Switching Cost*

Conceptually, customer relationship value depends on customer perceptions of the cost of switching to another supplier. Empirical tests of switching cost effects have been hampered because traditional performance measurement systems and customer satisfaction scores do not reflect switching cost perceptions within comparable market segments across firms. Using unique data systematically collected by market segment from online retail customers, we find that a) our switching cost proxy adds statistically significant explanatory power for both future buyer behaviors at the segment level and future financial performance at the firm level, and b) the positive relation between customer attitudes and future buyer behavior is increasing in switching cost. Our results show that externally generated non-financial data collected periodically across market segments can individually and jointly provide valuable information about segment and consolidated entity performance.
A biomimetic approach to dihydrobenzofuran synthesis.

A method for an acid-catalyzed construction of dihydrobenzofuran heterocycles (14) from 2-(2‘-hydroxyethyl)quinone precursors 10 is presented. The putative oxonium ion intermediate 17 formed by an intramolecular hydroxyl cyclization followed by dehydration is reduced in situ by an added dihydroquinone source. Good to excellent yields of cyclized products are realized in all cases except for highly electron deficient systems, and these suffer reduction prior to oxonium ion formation. All products are monomeric and derived from a two-electron transfer except for 10g, which affords the dimeric dihydrobenzofuran. The amount of cyclization or reduction product is governed by the HOMO/LUMO gap between the quinone substrate and the dihydroquinone additive, and the product distribution can be adjusted by modifying the electronic properties of the added reducing agent.
Investigation of porphyrin-forming reactions. Part 3. The origin of scrambling in dipyrromethane + aldehyde condensations yielding trans-A2B2-tetraarylporphyrins

The dipyrromethane + aldehyde condensation is a common method for the synthesis of trans-A2B2-porphyrins, but is often plagued by scrambling processes that lead to a mixture of porphyrins. The problem of scrambling is more pronounced with unhindered dipyrromethanes (e.g., 5-phenyldipyrromethane) than with hindered dipyrromethanes (e.g., 5-mesityldipyrromethane). We have characterized the oligomer composition (by LD-MS), yield of porphyrin (by UV–Vis), yield of N-confused porphyrin (by HPLC), and level of unreacted aldehyde (by TLC) in dipyrromethane + aldehyde condensations leading to trans-A2B2-porphyrins. Reaction conditions known to suppress scrambling in reactions involving 5-phenyldipyrromethane (PDPM) were compared to conditions known to provide extensive scrambling. The low-scrambling conditions were found to suppress scrambling by inhibiting reaction of oligomer fragments generated by acid-induced cleavage of the dipyrromethane, rather than by inhibiting acidolysis itself. However, such reaction conditions were also found to inhibit the condensation, leading to low yields (<10%) of porphyrin. The condensation of PDPM + aldehyde was also compared to reactions involving 5-mesityldipyrromethane (MDPM) to understand why trans-A2B2-porphyrins can be prepared in good yield devoid of scrambling from reactions using MDPM. The absence of scrambling in MDPM + aldehyde condensations was due to the resistance of MDPM to acidolysis. Taken together, these studies provide insight into the origin of scrambling with different types of substrates under different reaction conditions in the dipyrromethane + aldehyde route to trans-A2B2-porphyrins.
Remarks on fundamental string cosmology

Abstract In recent work, it was shown that velocity-dependent forces between moving strings or branes lead to an accelerating expanding universe without assuming the existence of a cosmological constant. Here we show that the repulsive velocity-dependent force arises in more general contexts and can lead to cosmic structure formation.
Edgewise Subdivision of a Simplex

In this paper we introduce the abacus model of a simplex and use it to subdivide a d-simplex into k d d-simplices all of the same volume and shape characteristics. The construction is an extension of the subdivision method of Freudenthal [3] and has been used by Goodman and Peters [4] to design smooth manifolds.
Extraction of electrostrong parameters of N∗(1520) from eta photoproduction

Abstract Recently obtained polarized target and photon asymmetry data in eta photoproduction are shown to be very powerful, in conjunction with the differential cross-section data, in yielding model-insensitive constraints on the electrostrong parameters for the excitation and decay of the N ∗ (1520) resonance. The extracted ratio of its electromagnetic helicity amplitudes, A 3 2 /A 1 2 , provides a critical test for the QCD-inspired hadron models.
Will Your Cognitive Anchor Hold in the Storms of Culture

s, databases, and other directed-research products in hardcopy and electronic media. The research includes a broad spectrum of social sciences, physical sciences, and humanities topics using the collections of the Library of Congress and other information sources world-wide.” McCutcheon: Will Your Cognitive Anchor Hold? Page 9 of 12
CCD Photometry of Galactic Globular Clusters. V. NGC 2808

We present a deep color-magnitude diagram for the Galactic globular cluster NGC 2808 (C0911-646), reaching 3 mag below the main-sequence turnoff. A set of local photometric standards are provided, and the mean cluster reddening and metallicity are constrained using several photometric techniques. The recently discovered unusual horizontal-branch morphology is confirmed. No significant radial population gradients are identified to within the limits of the data. We investigate the redward color spread on the main sequence previously reported by Ferraro et al. in a field centered 63 from the cluster center and attributed to binaries. We conclude that the spread is in the most part due to a non-Gaussian distribution of photometric errors about the main-sequence ridgeline.
Myosin II regulates extension, growth and patterning in the mammalian cochlear duct

The sensory epithelium of the mammalian cochlea comprises mechanosensory hair cells that are arranged into four ordered rows extending along the length of the cochlear spiral. The factors that regulate the alignment of these rows are unknown. Results presented here demonstrate that cellular patterning within the cochlea, including the formation of ordered rows of hair cells, arises through morphological remodeling that is consistent with the mediolateral component of convergent extension. Non-muscle myosin II is shown to be expressed in a pattern that is consistent with an active role in cellular remodeling within the cochlea, and genetic or pharmacological inhibition of myosin II results in defects in cellular patterning that are consistent with a disruption in convergence and extension. These results identify the first molecule, myosin II, which directly regulates cellular patterning and alignment within the cochlear sensory epithelium. Our results also provide insights into the cellular mechanisms that are required for the formation of highly ordered cellular patterns.
Unified Field Theory From Enlarged Transformation Group. The Covariant Derivative for Conservative Coordinate Transformations and Local Frame Transformations

Pandres has developed a theory in which the geometrical structure of a real four-dimensional space-time is expressed by a real orthonormal tetrad, and the group of diffeomorphisms is replaced by a larger group called the conservation group. This paper extends the geometrical foundation for Pandres’ theory by developing an appropriate covariant derivative which is covariant under all local Lorentz (frame) transformations, including complex Lorentz transformations, as well as conservative transformations. After defining this extended covariant derivative, an appropriate Lagrangian and its resulting field equations are derived. As in Pandres’ theory, these field equations result in a stress-energy tensor that has terms which may automatically represent the electroweak field. Finally, the theory is extended to include 2-spinors and 4-spinors.
A frequency-hopping approach for microwave imaging of large inhomogeneous bodies

A frequency-hopping approach is proposed to process multifrequency CW microwave measurement data so that larger dielectric bodies for microwave imaging can be reconstructed with higher fidelity compared to a single-frequency reconstruction. The frequency hopping approach uses only data at a few frequencies, and hence can reduce data acquisition time in a practical system. Moreover, the frequency-hopping approach overcomes the effect of nonlinearity in the optimization procedure so that an algorithm is not being trapped in local minima. In this manner, larger objects with higher contrasts could be reconstructed without a priori information. We demonstrate the reconstruction of an object 10 wavelengths in diameter with permittivity profile contrast larger than 1:2 without using a priori information.
A unified approach to multiple stopping and duality

Abstract The main approaches to dual representations of multiple stopping problems are the marginal and pure martingale approaches of Meinshausen and Hambly (2004) [17] and Schoenmakers (2010) [20] , respectively. We show that these dual representations, as well as their more recent extensions to problems with volume constraints, can be derived in a simple unified manner using the recently developed general duality theory based on information relaxations. We also derive pure martingale representations for other multiple stopping problems, including problems with refractive index constraints.
Pick Matricies and Quaternionic Power Series

It is well known that a non-constant complex-valued function f defined on the open unit disk \({\mathbb{D}}\) of the complex plane is an analytic self-mapping of \({\mathbb{D}}\) if and only if Pick matrices \({\left[ (1 - f(z_i)\overline{f(z_j)})/\right.\left.(1 - z_i\overline{z}_j)\right]_{i,j=1}^n}\) are positive semidefinite for all choices of finitely many points \({z_{i} \in \mathbb{D}}\). A stronger version of the “if” part was established by Hindmarsh (Pac J Math 27:527–531, 1968): if all 3 × 3 Pick matrices are positive semidefinite, then f is an analytic self-mapping of \({\mathbb{D}}\). In this paper, we extend this result to the non-commutative setting of power series over quaternions.
Spectral Resolution of Near-Resonant Rayleigh Scattering and Collision-Induced Resonance Fluorescence

Light scattered from strontium vapor near its 460.73-nm ($^{1}{P}_{1}^{\ensuremath{\circ}}\ensuremath{-}^{1}S_{0}$) resonance transition was resolved into its three spectral components: Rayleigh scattering, collision-induced fluorescence, and three-photon scattering. The saturation behavior of the central (Rayleigh) component and the intensity and ac Stark shift of the three-photon component were studied as a function of detuning and laser intensity. Good agreement is obtained with theoretical predictions.
Distortion elements in group actions on surfaces

If G is a finitely generated group with generators {g1,…,gj}, then an infinite-order element f∈G is a distortion element of G provided that lim infn→∞|fn|/n=0, where |fn| is the word length of fn in the generators. Let S be a closed orientable surface, and let Diff(S)0 denote the identity component of the group of C1-diffeomorphisms of S. Our main result shows that if S has genus at least two and that if f is a distortion element in some finitely generated subgroup of Diff(S)0, then supp(μ)⊂Fix(f) for every f-invariant Borel probability measure μ. Related results are proved for S=T2 or S2. For μ a Borel probability measure on S, denote the group of C1-diffeomorphisms that preserve μ by Diffμ(S). We give several applications of our main result, showing that certain groups, including a large class of higher-rank lattices, admit no homomorphisms to Diffμ(S) with infinite image