cssi/SciSciGPT-SciSciNet huggingface dataset:
Medical Interventions Among Pregnant Women in Fee-for-Service and Managed Care Insurance: a Propensity Score Analysis

This paper extends earlier research on the effect of managed care on the receipt of four medical interventions for pregnant women: ultrasound, induction/stimulation of birth, electronic fetal monitor, and Caesarean delivery. Propensity score methods are used to account for sample selection issues regarding insurance choice. Managed care enrollees are more likely to receive an ultrasound, which may be indicative of receiving better prenatal care. Managed care plans reduce the rate of Caesarean deliveries, but such limitations may be beneficial given the substantial medical evidence that Caesarean deliveries are over-utilized. The results indicate that insurance coverage does influence treatment intensity, but that utilization controls and provider financial incentives do not adversely affect care for pregnant women.
A direct analysis of nonlinear systems with external periodic excitations via normal forms

This study presents a direct methodology for a quantitative analysis of nonlinear dynamic systems with external periodic forcing via an application of the theory of normal forms. Rather than introducing a new state variable to reduce the problem to a homogeneous one, a set of time-dependant near-identity transformations is applied to construct the normal forms. In the process, the total response of the system is expressed as superposition of a steady state solution and a transient solution. A steady state solution of the system is obtained by the method of harmonic balance and the transient solution is obtained by solving a set of time periodic homological equations. The proposed method can be applied to time-invariant as well as time varying systems. After discussing the time-invariant case, the methodology is extended to systems with time-periodic coefficients. The case of time periodic systems is handled through an application of the Lyapunov–Floquet (L–F) transformation. Application of the L–F transformation produces a dynamically equivalent system in which the linear part of the system is time-invariant, making the system amenable to near-identity transformations. An example for each type of system, namely, constant coefficients and time-varying coefficients, is included to demonstrate effectiveness of the method. Various resonance conditions are discussed. It is observed that the linear parametric excitation term need not be small as generally assumed in perturbation and averaging techniques. Results obtained by proposed methods are compared with numerical solutions. Close agreements are found in some typical applications.
Stock Splits: An Institutional Investor Preference

This study examines the relationship between the level of institutional ownership and the likelihood that firms will enact a stock split. There is evidence of a positive relationship between institutional ownership and subsequent split behavior. A firm size effect emerges from the finding that larger firms have higher percentages of institutional owners. This implies that institutional investors either encourage stock split behavior or invest in firms that exhibit indicators of eminent stock splits. Institutions purchasing shares before the split are likely to obtain short-term and long-term earmings increases.
On Hitting Times and Fastest Strong Stationary Times for Skip-Free and More General Chains

An (upward) skip-free Markov chain with the set of nonnegative integers as state space is a chain for which upward jumps may be only of unit size; there is no restriction on downward jumps. In a 1987 paper, Brown and Shao determined, for an irreducible continuous-time skip-free chain and any d, the passage time distribution from state 0 to state d. When the nonzero eigenvalues νj of the generator on {0,…,d}, with d made absorbing, are all real, their result states that the passage time is distributed as the sum of d independent exponential random variables with rates νj. We give another proof of their theorem. In the case of birth-and-death chains, our proof leads to an explicit representation of the passage time as a sum of independent exponential random variables. Diaconis and Miclo recently obtained the first such representation, but our construction is much simpler.
First example of reversal of normal stereoselectivity in the intramolecular Pauson-Khand reaction

Stereoselectivity favoring exo substituent orientation in the intramolecular Pauson-Khand reaction of 3-methyl-4-hydroxy-1,6-heptenynes to form bicyclo[3.3.0]octenones is affected by the relative stereochemistry at C3 and C4. Cycloaddition of one stereoisomer of 3,5-dimethyl-4-propargyl-1,6-heptadiene gives predominantly the bicyclo[3.3.0]octenone isomer containing both substituents in more hindered endo orientations. An explanation based upon the effect of conformational preferences prior to metallacycle formation is proposed.
Synthesis of trans-3,4-dihydroxy-3,4-dihydrophenanthro[3,2-b][1]benzothiophene, a potentially carcinogenic metabolite of sulfur heterocycle phenanthro[3,2-b][1]benzothiophene

The present study describes the synthesis of trans-3,4-dihydroxy-3,4-dihydrophenanthro[3,2-b][1]benzothiophene (3), which is a potential proximate carcinogen of the environmentally occurring potent carcinogen phenanthro[3,2-b][1]benzothiophene (1). Three approaches were investigated for the synthesis of 3. In the first approach, the diarylalkene 9, which was prepared by the Wittig reaction of ylide 7 and aldehyde 8, was subjected to an oxidative photocyclization reaction to produce a mixture of compounds from which 5, a synthetic precursor to 3, was obtained only in trace amounts. The major cyclized product was 10. The second approach entailed the Suzuki cross-coupling reaction of 2-(dihydroxyboryl)-5-methoxybenzaldehyde (12) with 3-bromodibenzothiophene (11) to produce 13 in 92% yield. The aldehyde function of 13 was elongated with trimethylsulfonium iodide in the presence of KOH to generate the ethylene oxide 14, which, after methanesulfonic acid treatment, produced a 1 ∶ 1 mixture of 3-methoxyphenanthro[3,2-b][1]benzothiophene (6) and 3-methoxyphenanthro[1,2-b][1]benzothiophene (15). Only the undesired compound 15 could be isolated in pure form by extracting the mixture with hot ethanol, leaving behind a 7 ∶ 3 mixture of 6 and 15. In the third approach, the Wittig reaction of 7 with 2-bromo-5-methoxybenzaldehyde (16) produced 17 predominantly as the Z-isomer in quantitative yield. Cyclodehydrobromination of 17 with KOH–quinoline at elevated temperature produced a mixture from which 6 and 3-methoxyphenanthro[3,4-b][1]benzothiophene (18) were easily separated by column chromatography in 23 and 51% yields, respectively. The intermediate 6 was conveniently processed to 3 following the reaction sequence: methoxy phenol→o-quinone→dihydrodiol. A relatively polar dihydrodiol obtained by similar processing of the mixture of 6 and 15 was identified as 3.
Catalytic Enantioselective Meerwein−Eschenmoser Claisen Rearrangement: Asymmetric Synthesis of Allyl Oxindoles

The first catalytic, enantioselective Meerwein−Eschenmoser Claisen rearrangement has been achieved. Palladium(II) BINAP or phosphinooxazoline catalysts were employed to generate oxindole products with 100% conversion and up to 92% ee.
Design and fabrication of a reflection far-ultraviolet polarizer and retarder

New methods have been developed for the design of a far ultraviolet multilayer reflection polarizer and retarder. A MgF2/Al/MgF2 three-layer structure deposited on a thick opaque Al film (substrate) is used for the design of polarizers and retarders. The induced transmission and absorption method is used for the design of a polarizer and layer-by-layer electric field calculation method is used for the design of a quarterwave retarder. In order to fabricate these designs in a conventional high vacuum chamber, we have to minimize the oxidation of the Al layers and somehow characterize the oxidized layer. X-ray photoelectron spectroscopy is used to investigate the amount and profile of oxidation. Depth profiling results and a seven layer oxidation model are presented.
Orifice Diameter Effects on Diesel Fuel Jet Flame Structure

The effects of orifice diameter on several aspects ofdiesel fuel jet flame structure were investigated in a constant-volume combustion vessel under heavy-duty direct-injection (DI) diesel engine conditions using Phillips research grade #2 diesel fuel and orifice diameters ranging from 45 μm to 180 μm. The overall flame structure was visualized with time-averaged OH chemiluminescence and soot luminosity images acquired during the quasi-steady portion of the diesel combustion event that occurs after the transient premixed burn is completed and the flame length is established. The lift-off length, defined as the farthest upstream location of high-temperature combustion, and the flame length were determined from the OH chemiluminescence images. In addition, relative changes in the amount of soot formed for various conditions were determined from the soot incandescence images. Combined with previous investigations of liquid-phase fuel penetration and spray development, the results show that air entrainment upstream of the lift-off length (relative to the amount of fuel injected) is very sensitive to orifice diameter As orifice diameter decreases, the relative air entrainment upstream of the lift-off length increases significantly. The increased relative air entrainment results in a reduced overall average equivalence ratio in the fuel jet at the lift-off length and reduced soot luminosity downstream of the lift-off length. The reduced soot luminosity indicates that the amount of soot formed relative to the amount of fuel injected decreases with orifice diameter. The flame lengths determined from the images agree well with gas jet theory for momentum-driven nonpremixed turbulent flames.
Frictional and Internal Leakage Losses in Rotary-Vane Two-Phase Refrigerating Expanders

Increasing the coefficient of performance of a vapor compression refrigeration system may be realized by utilizing work recovering expansion devices that additionally lower the enthalpy of the refrigerant at the inlet of the evaporator. Depending on the operational and geometrical parameters of the expander, laminar and viscous two-phase leakage flows within the expander may be present. Single-phase leakage models available in the literature must then be modified or rederived accordingly. A dynamic frictional model for the expander must also be developed for ideal operation (i.e., no internal leakage) and modified to account for internal leakage accordingly. This paper presents a comprehensive component-level model of inherent friction and internal leakage losses in a two-phase circular rotary-vane expander used in a vapor compression refrigeration system. The model establishes the performance of the expander as a function of geometric and fluid parameters. Accurate modeling and prediction of frictional and internal leakage losses is vital to being able to accurately estimate the efficiency, rotational speed, and the torque and power produced by the expander. Directions for future work are also discussed.
A recursion and a combinatorial formula for Jack polynomials

The Jack polynomials J (x; ) form a remarkable class of symmetric polynomials. They are indexed by a partition and depend on a parameter . One of their properties is that several classical families of symmetric functions can be obtained by specializing , e.g., the monomial symmetric functions m ( =∞), the elementary functions e ′ ( = 0), the Schur functions s ( = 1) and nally the two classes of zonal polynomials ( = 2, = 1=2). The Jack polynomials can be de ned in various ways, e.g.: a) as an orthogonal family of functions which is compatible with the canonical ltration of the ring of symmetric functions or b) as simultaneous eigenfunctions of certain di erential operators (the Sekiguchi–Debiard operators). Recently Opdam, [O], constructed a similar family F (x; ) of nonsymmetric polynomials. The index runs now through all compositions ∈ Nn. They are de ned in a completely similar fashion, e.g., the Sekiguchi–Debiard operators are being replaced by the Cherednik di erential-re ection operators (see Sect. 3). It is becoming more and more clear that these polynomials are as important as their symmetric counterparts. The purpose of this paper is to add to the existing characterizations of Jack polynomials two further ones: c) a recursion formula among the F together with two formulas to obtain J from them. d) combinatorial formulas of both J and F in terms of certain generalized tableaux.
Symmetry of the pairing, isotope effect and mechanism of superconductivity in the cuprates

Abstract This article will briefly discuss the symmetry of the pairing, the isotope effect and the strong coupling of the carriers to the optical phonon modes which is strong enough to provide high T c .
Velocity requirements and re-entry flight mechanics for manned mars missions

A survey of manned Mars mission studies was conducted. For missions initiated from Earth orbit, these studies have shown that, without aerodynamic braking, the total propulsive velocity requirements are 64,000 to 95,000 fps for the "short" trip (400 to 500 days). The use of aerodynamic braking at Mars or on Earth return results in a significant reduction in total propulsive velocity requirements, as well as a reduction in the effects of launch year on these requirements. Earth entry velocities vary from 46,000 to 73,000 fps and Mars entry velocities from 19,000 to 36,000 fps for the Mars short trip, depending on the launch period. Following this survey, an analysis of the Earth entry phase of the mission was conducted to evaluate the minimum re-entry vehicle L/D requirements based on a re-entry corridor width of 10 miles. Vehicles capable of pitch angle modulation for peak g reduction were found to require significantly lower L/D capability and lower total stagnation-point heat loads than those with roll-control capability only. Earth entry vehicles capable of the pitch-modulation maneuver therefore merit further study, especially in the area of total body heating and thermal-protection requirements.
Report of the Radionuclides in Nephrourology Committee on Renal Clearance

The need for simple and accurate methods to measure renal function is self-evident. This need increases as techniques for intervention become available. The demand for evaluation of individual kidney function has increased with its role in the diagnosis and follow-up of unilateral renal disease and in decision making for conservative or surgical treatment based on residual renal function. The role of nuclear medicine in this area has been inhibited by confusion about conflicting methodologies. This report is meant to provide guidance to those centers that would like to initiate clearance procedures but have difficulty in choosing appropriate methodology.
Equation of state for "classical" helium.

A classical base-line equation of state for fluid helium is calculated from a recent accurate pair potential and a classical statistical-mechanical theory. The range covered is 2.5--1400 K and densities up to 90 mol/${\mathrm{dm}}^{3}$. Comparison with experimental data shows how quantum effects in $^{4}\mathrm{He}$ behave in the dense-fluid region. A pseudoclassical calculation based on experimental second virial coefficients fails to account for the high-density quantum effects. The volume expansion caused by zero-point motion can be directly seen in the curvature of the Zeno line.
Robust Control of PVTOL Aircraft with a Nonlinear Optimal Control Solution

In this paper, a new nonlinear control strategy is proposed for hovering control of planar vertical takeoff and landing (PVTOL) aircraft. The control of this typical nonlinear, nonminimum-phase system is treated as a robust control problem. The robust control design is then converted to an equivalent optimal control design so that both stabilization and performance can be guaranteed. The primary contribution of this work is to provide a closed-form solution to the resultant nonlinear optimal control problem by employing a recently emerging nonlinear control approach, called the θ−D technique. The θ−D technique is based on optimal control theory and derived from an approximate solution to the Hamilton-Jacobi-Bellman equation via a perturbation process. This formulation will not only enhance the system performance but also simplify the design process in that robustness and optimality are integrated in one unified optimal control framework. Furthermore, the closed-form control law is very suitable for onboar...
Modeling Eclipses of the Novalike Variable TT Triangulum

Multicolor (BVRI) light curves of the eclipsing novalike variable TT Tri are presented. The eclipse profiles are analyzed with a parameter-fitting model that assumes four sources of luminosity: a white dwarf primary star, a main-sequence secondary star, a flared accretion disk with a rim, and a bright spot at the intersection of the mass-transfer stream and the disk periphery. Model parameters include the temperatures of the white dwarf, T1, and the secondary star, T2, the radius Rd and temperature Td of the disk periphery, the inner disk radius Rin, the disk power-law radial brightness temperature exponent α and thickness parameter hr, and a bright spot temperature enhancement factor χs. A grid of model light curves was computed, covering an extensive range of plausible parameter values. The models were then compared with the mean BVRI light curves to determine the optimum values for the fitting parameters and their associated errors. The mass ratio of TT Tri is poorly constrained in our models but must lie roughly in the range 0.3 q 0.9 (where q = M2/M1). Models characterized by mass ratios of q = 0.3 (), q = 0.6 (), and q = 0.9 () were all capable of providing acceptable fits to the data, although the best fits were achieved for mass ratios near the upper end of the permitted range (q = 0.6 and 0.9). The values of the remaining fitting parameters were found to be insensitive to the adopted mass ratio and rim thickness. The accretion disk was found to extend to ~50%-60% of the distance to the inner Lagrangian point in all models but came closer to reaching the tidal limit (as expected for steady state accretion) in the higher mass ratio models. The same behavior was found for the radial temperature profile of the disk, which increased with mass ratio, becoming more consistent with that expected for steady state accretion in the q = 0.6 and q = 0.9 models. Models with a truncated inner disk (Rin R1) generally resulted in a higher white dwarf temperature and a steepening of the disk temperature profile but were not required to achieve a viable steady state disk solution. No evidence was found for a luminous bright spot in the system, which is not surprising given the lack of a pre-eclipse "hump" in the light curve. A total of 22 eclipse timings were measured for the system, which yielded an ephemeris for the times of mideclipse given by HJD = 2,453,618.953(3) + 0.1396369(4)E. A comparison of the observed brightness and color at mideclipse with the photometric properties of the best-fitting model suggests that TT Tri lies at a distance of ~400-500 pc.
Health psychology in the 21st century: Acquired Immunodeficiency Syndrome as a harbinger of things to come

An increasing focus on the human immunodeficiency virus (HIV) is important given the role of health psychology in preventing further spread of the epidemic and in maintaining quality of life in the...
Diverse spreading behavior of binary polymer nanodroplets.

Molecular dynamics simulations are used to study the spreading of binary polymer nanodroplets in a cylindrical geometry. The polymers, described by the bead−spring model, spread on a flat surface with a surface-coupled Langevin thermostat to mimic the effects of a corrugated surface. Each droplet consists of chains of length 10 or 100 monomers with ∼350 000 monomers total. The qualitative features of the spreading dynamics are presented for differences in chain length, surface interaction strength, and composition. When the components of the droplet differ only in the surface interaction strength, the more strongly wetting component forms a monolayer film on the surface even when both materials are above or below the wetting transition. In the case where the only difference is the polymer chain length, the monolayer film beneath the droplet is composed of an equal amount of short chain and long chain monomers even when one component (the shorter chain length) is above the wetting transition and the other ...
Synthesis of new hybrid macromolecules with cyclo-dendritic architecture

Novel cyclo-dendritic hybrid macromolecules were synthesized using preformed blocks: hydroxymethyl crown ethers and poly(benzyl ether) monodendrons.
Nature of lattice distortion in one-dimensional dangling-bond wires on Si and C

The structure of one-dimensional ``dangling-bond wires'' fabricated on H-passivated Si and diamond (001) surfaces has been determined by first-principles calculations. The dangling-bond wire on Si(001) exhibits a lattice distortion with an alternating up and down displacement, whereas such a distortion is suppressed in that on C(001). These contrasting behaviors for both cases are attributed to the different chemical trend of Si and C dangling bonds in a rehybridization of the dangling orbital. Our analysis shows that the underlying mechanism of the lattice distortion in the dangling-bond wire on Si(001) is not related with a Peierls instability, but is analogous to that of the dimer reconstruction at the clean Si(001) surface.
Synthesis of a Cyclitol via a Tandem Enzymatic Aldol - Intramolecular Horner-Wadsworth-Emmons Reaction

Abstract The aldol condensation between a phosphonate aldehyde and dihydroxyacetone phosphate catalyzed by fructose 1,6-diphosphate aldolase (EC 4.1.2.13) gives a product which in situ cyclizes via an intramolecular Horner-Wadsworth-Emmons (HWE) olefination to afford a polyhydroxylated cyclopentene. In this one-pot reaction, the HWE reaction takes place in aqueous solution at slightly acidic (pH 6.1–6.8) conditions.
Particle Dynamics Simulations of Rate- and State-dependent Frictional Sliding of Granular Fault Gouge

Recent simulations using the particle dynamics method (PDM) have successfully captured many features of natural faults zones as illuminated in laboratory studies. However, 2-D simulations conducted on idealized assemblages of particles using simple elastic-frictional contact laws, yield friction values considerably lower than natural materials, and lack time- and velocity-dependent changes in strength that influence dynamic fault slip. Here, preliminary results of new PDM simulations are described, in which particle motions are restricted as a proxy for particle interlocking and out of plane contacts, and time-dependent contact healing is introduced to capture temporal strengthening of granular assemblages. Frictional strength is increased, and in the absence of interparticle rolling, can attain values observed in the laboratory. The resulting mechanical behavior is qualitatively similar to that described by empirically-based rate-state friction laws, providing new physical insight into the discrete mechanics of natural faults.
Local holomorphic isometries of a modified projective space into a standard projective space; rational conformal factors

We consider local modifications \(\omega _n+f^*\omega _d\) of the Fubini-Study metric (with associated \((1,1)\)-form \(\omega _n\)) on an open subset \(\Omega \subset \mathbb C\mathbb P^n\) induced by a local holomorphic mapping \(f:\Omega \rightarrow \mathbb P^d\). Our main result is that there are “gaps” in potential dimensions \(m\) such that the modification can be obtained as \(h^*\omega _m\) for some local holomorphic mapping \(h:\Omega \rightarrow \mathbb C\mathbb P^m\). We also consider the case of rational conformal factors.
CANONICAL CORRELATION ANALYSIS BETWEEN TIME SERIES AND STATIC OUTCOMES, WITH APPLICATION TO THE SPECTRAL ANALYSIS OF HEART RATE VARIABILITY.

Although many studies collect biomedical time series signals from multiple subjects, there is a dearth of models and methods for assessing the association between frequency domain properties of time series and other study outcomes. This article introduces the random Cramer representation as a joint model for collections of time series and static outcomes where power spectra are random functions that are correlated with the outcomes. A canonical correlation analysis between cepstral coefficients and static outcomes is developed to provide a flexible yet interpretable measure of association. Estimates of the canonical correlations and weight functions are obtained from a canonical correlation analysis between the static outcomes and maximum Whittle likelihood estimates of truncated cepstral coefficients. The proposed methodology is used to analyze the association between the spectrum of heart rate variability and measures of sleep duration and fragmentation in a study of older adults who serve as the primary caregiver for their ill spouse.
Compensation for extreme outages caused by polarization mode dispersion and amplifier noise

Fluctuations of Bit-Error-Rate (BER) stimulated by birefringent disorder in an optical fiber system are found to be strong. The effect may not be analyzed in terms of the average BER but rather requires analyzing the Probability Distribution Function (PDF) of BER. We report the emergence of the extremely extended algebraic-like tail of the PDF, corresponding to anomalously large values of BER. We analyze the dependence of the PDF tail, and thus the outage probability, on the first-order PMD compensation scheme. Effectiveness of compensation is illustrated quantitatively using a simple, however, practical example.
Requiem for Kyoto: An Economic Analysis of the Kyoto Protocol

This paper uses the newly developed RICE-98 model to analyze the economics of the Kyoto Protocol. It analyzes versions of the Kyoto Protocol that have different approaches to trading emissions rights and compares these with efficient approaches. The major conclusions are: (a) the net global cost of the Kyoto Protocol is $716 billion in present value, (b) the United States bears almost two-thirds of the global cost; and (c) the benefit-cost ratio of the Kyoto Protocol is 1/7. Additionally, the emissions strategy is highly costineffective, with the global temperature reduction achieved at a cost almost 8 times the cost of a strategy which is cost-effective in terms of “where” and “when” efficiency. These conclusions assume that trading in carbon permits is allowed among Annex I countries.
Stochastic stability analysis for continuous-time fault tolerant control systems

Active fault tolerant control systems are feedback control systems that reconfigure the control law in real time based on the response from an automatic failure detection and identification (FDI) scheme. The dynamic behaviour of such systems is characterized by stochastic differential equations because of the random nature of the failure events and the FDI decisions. The stability analysis of these systems is addressed in this paper using stochastic Lyapunov functions and supermartingale theorems. Both exponential stability in the mean square and almost-sure asymptotic stability in probability are addressed. In particular, for linear systems where the coefficients of the closed loop system dynamics are functions of two random processes with markovian transition characteristics (one representing the random failures and the other representing the FDI decision behaviour), necessary and sufficient conditions for exponential stability in the mean square are developed.
On the support of the Ashtekar-Lewandowski Measure

We show that the Ashtekar-Isham extension\(\overline {A/G}\) of the configuration space of Yang-Mills theories\(A/G\) is (topologically and measure-theoretically) the projective limit of a family of finite dimensional spaces associated with arbitrary finite lattices.
A Model for Communication in Clusters of Multi-core Machines

A common paradigm for scientific computing is distributed message-passing systems, and a common approach to these systems is to implement them across clusters of high-performance workstations. As multi-core architectures become increasingly mainstream, these clusters are very likely to include multi-core machines. However, the theoretical models which are currently used to develop communication algorithms across these systems do not take into account the unique properties of processes running on shared- memory architectures, including shared external network connections and communication via shared memory locations. Because of this, existing algorithms are far from optimal for modern clusters. Additionally, recent attempts to adapt these algorithms to multicore systems have proceeded without the introduction of a more accurate formal model and have generally neglected to capitalize on the full power these systems offer. We propose a new model which simply and effectively captures the strengths of multi-core machines in collective communications patterns and suggest how it could be used to properly optimize these patterns.
On the Ineffective Education of Decision Scientists

There is general agreement that the training of decision scientists during the past ten years has left much to be desired. This note presents nine rules relating to the fundamental reasons for the failure of training programs, along with suggestions for improving the present state of affairs.
Isospin Physics in Heavy-Ion Collisions at Intermediate Energies

In nuclear collisions induced by stable or radioactive neutron-rich nuclei a transient state of nuclear matter with an appreciable isospin asymmetry as well as thermal and compressional excitation can be created. This offers the possibility to study the properties of nuclear matter in the region between symmetric nuclear matter and pure neutron matter. In this review, we discuss recent theoretical studies of the equation of state of isospin-asymmetric nuclear matter and its relations to the properties of neutron stars and radioactive nuclei. Chemical and mechanical instabilities as well as the liquid-gas phase transition in asymmetric nuclear matter are investigated. The in-medium nucleon-nucleon cross sections at different isospin states are reviewed as they affect significantly the dynamics of heavy ion collisions induced by radioactive beams. We then discuss an isospin-dependent transport model, which includes different mean-field potentials and cross sections for the proton and neutron, and its applic...
Reducing salinity and organic contaminants in the Pearl Harbor dredged material using soil amendments and plants

Phytoremediation is an emerging technique that can be used to economically remediate sites contaminated with trace elements and/or man-made organic contaminants. This technique was used on Pearl Harbor (Oahu, Hawaii) dredged material (PHDM) containing polycyclic aromatic hydrocarbons (PAHs) and some heavy metals. The dredged material was first amended with a high-calcium soil (Waialua Mollisol) and a biosolids-based compost at different proportions to yield varying salinity levels. A mixture that yielded an electrical conductivity (EC, a measure of salinity) of the saturated paste extract of 15 to 20 dS/m was identified and used to evaluate the salt tolerance of five plant species. Relative germination and one-month-old biomass indicated that common bermuda grass (Cynodon dactylon), seashore paspalum (Paspalum vaginatum), beach pea (Vigna marina), and cow pea (Vigna unguiculata) can produce at least 40 percent of biomass of the control at an EC of approximately 18 dS/m, suggesting the four plants are relatively salt tolerant. In contrast, Desmodium intortum either did not germinate or died within two weeks after germination at the same salinity level. A subsequent greenhouse experiment, using mixtures of the PHDM (0 or 25 percent dry weight), organic amendments (10 percent leucaena green manure or biosolids-based compost), and a Mollisol (65 or 90 percent dry weight) in 6-liter pots containing 4 kilograms of material yielded the following results: (1) a combination of transplanted seashore paspalum, seeded bermuda grass, and seeded beach pea was effective in taking up sodium (Na), thereby reducing salinity and making the medium more amenable to diversified microbes and plants, which may be effective PAH degraders; (2) total PAH concentration was reduced by about 30 percent after three months of active plant growth, but degradation of individual PAH members varied significantly, however; (3) leguminous green manure, as a soil amendment, was more effective than compost for use in bio- and/or phyto-remediations; and (4) soil amendments, when applicable, could supplement living plants in reducing organic contaminants, such as PAHs. © 2003 Wiley Periodicals, Inc. Reprinted from Remediation Volume 12, Number 4.
A Parallel Methodology for Reduction of Coupling in Distributed Business-to-Business E-Commerce Transactions

Recently, new standards for business-to-business (B2B) e-commerce transactions, to reduce extended record locking, relaxed standard database transaction properties. In this paper, we provide a parallel methodology employing a mobile/intelligent agent framework to alleviate extended record locking, while adhering to standard database transaction properties. Our methodology provides a minimum 30% reduction of record locking compared to new B2B standards.
A Metal-Catalyzed Intermolecular [5+2] Cycloaddition/Nazarov Cyclization Sequence and Cascade

The bicyclo[5.3.0]decane skeleton is one of the most commonly encountered bicyclic subunits in nature and the core scaffold of a wide range of targets of structural, biological, and therapeutic importance. Prompted by the interest in such structures, we report the first studies of metal-catalyzed [5+2] cycloadditions of vinylcyclopropanes (VCPs) and enynones. The resultant efficiently formed dienone cycloadducts serve as substrates for subsequent Nazarov cyclizations and as intermediates for single-operation [5+2]/Nazarov serial reactions and catalytic cascades. In many cases the one-flask process can be carried out in shorter reaction times and with comparable or superior yields to the two-flask procedure. Significantly, a single catalyst can be used to mediate both transformations. These [5+2]/Nazarov reaction sequences and cascades collectively provide strategically novel and facile access to the bicyclo[5.3.0]decane skeleton from simple and readily available components.
Concerning the Phosphorylation of Vicinal Diols

Abstract The specific use of n-butyllithium as the base for reaction of diethyl phosphorochloridate with diols leads to the formation of diphosphate esters in good to excellent yields without any evidence for the formation of 5-, 6-, or 7-membered cyclic phosphates.
Graphene Microbolometers with Superconducting Contacts for Terahertz Photon Detection

We report on noise and thermal conductance measurements taken in order to determine an upper bound on the performance of graphene as a terahertz photon detector. The main mechanism for sensitive terahertz detection in graphene is bolometric heating of the electron system. To study the properties of a device using this mechanism to detect terahertz photons, we perform Johnson noise thermometry measurements on graphene samples. These measurements probe the electron–phonon behavior of graphene on silicon dioxide at low temperatures. Because the electron–phonon coupling is weak in graphene, superconducting contacts with large gap are used to confine the hot electrons and prevent their out-diffusion. We use niobium nitride leads with a $$T_\mathrm {c}\approx 10$$ K to contact the graphene. We find these leads make good ohmic contact with very low contact resistance. Our measurements find an electron–phonon thermal conductance that depends quadratically on temperature above 4 K and is compatible with single terahertz photon detection.
Fractional quantum hall effect and electron correlations in partially filled first excited Landau level

Abstract We present a quantitative study of most prominent incompressible quantum Hall states in the partially filled first excited Landau level (LL1) which have been recently studied experimentally by Choi et al. The pseudopotential describing the electron–electron interaction in LL1 is harmonic at short range. It produces a series of incompressible states which is different from its LL0 counterpart. The numerical data indicate that the most prominent states ν = 5 2 , 7 3 and 8 3 are not produced by Laughlin correlated electrons, but result from a tendency of electrons to form pairs or larger clusters which eventually become Laughlin correlated. States with smaller gaps at filling factors 14 5 , 16 7 , 11 5 , 19 7 are Laughlin correlated electron or hole states and fit Jain's sequence of filled CF 4 levels.
Sodium dodecyl sulfate monomers induce XAO peptide polyproline II to α-helix transition.

XAO peptide (Ac–X2A7O2–NH2; X: diaminobutyric acid side chain, −CH2CH2NH3+; O: ornithine side chain, −CH2CH2CH2NH3+) in aqueous solution shows a predominantly polyproline II (PPII) conformation without any detectable α-helix-like conformations. Here we demonstrate by using circular dichroism (CD), ultraviolet resonance Raman (UVRR) and nuclear magnetic resonance (NMR) spectroscopy that sodium dodecyl sulfate (SDS) monomers bind to XAO and induce formation of α-helix-like conformations. The stoichiometry and the association constants of SDS and XAO were determined from the XAO–SDS diffusion coefficients measured by pulsed field gradient NMR. We developed a model for the formation of XAO–SDS aggregate α-helix-like conformations. Using UVRR spectroscopy, we calculated the Ramachandran ψ angle distributions of aggregated XAO peptides. We resolved α-, π- and 310- helical conformations and a turn conformation. XAO nucleates SDS aggregation at SDS concentrations below the SDS critical micelle concentration. The ...
Unhealthy Assimilation: Why Do Immigrants Converge to American Health Status Levels?

It is well documented that immigrants are in better health upon arrival in the United States than their American counterparts but that this health advantage erodes over time. We study the potential determinants of this “healthy immigrant effect,” with a particular focus on the tendency of immigrants to converge to unhealthy American BMI levels. Using data from the National Health Interview Survey, we find that average female and male immigrants enter the United States with BMIs that are approximately two and five percentage points lower than native-born women and men, respectively. Consistent with the declining health status of immigrants the longer they remain in the United States, we also find that female immigrants almost completely converge to American BMIs within 10 years of arrival, and men close a third of the gap within 15 years.
Line defects, tropicalization, and multi-centered quiver quantum mechanics

We study BPS line defects in $$ \mathcal{N} $$ = 2 supersymmetric four-dimensional field theories. We focus on theories of “quiver type,” those for which the BPS particle spectrum can be computed using quiver quantum mechanics. For a wide class of models, the renormalization group flow between defects defined in the ultraviolet and in the infrared is bijective. Using this fact, we propose a way to compute the BPS Hilbert space of a defect defined in the ultraviolet, using only infrared data. In some cases our proposal reduces to studying representations of a “framed” quiver, with one extra node representing the defect. In general, though, it is different. As applications, we derive a formula for the discontinuities in the defect renormalization group map under variations of moduli, and show that the operator product algebra of line defects contains distinguished subalgebras with universal multiplication rules. We illustrate our results in several explicit examples.
Highly enantioselective direct reductive coupling of conjugated alkynes and α-ketoesters via rhodium-catalyzed asymmetric hydrogenation

Catalytic hydrogenation of 1,3-enynes 1a−7a in the presence of ethyl pyruvate and related activated ketones using chirally modified cationic rhodium catalysts results in reductive coupling to afford dienylated α-hydroxy esters 1b−7b and 3c−3f with exceptional levels of regio- and enantiocontrol. These studies represent the first highly enantioselective direct catalytic reductive couplings of alkynes to ketones. As illustrated by the conversion of 6b to 6c−6h, the diene containing the side chain of the coupling products is subject to diverse chemo- and regioselective manipulation. Reductive coupling of enyne 6a and ethyl pyruvate using elemental deuterium provides the monodeuterated product deuterio-6b, consistent with a catalytic mechanism involving alkyne−carbonyl oxidative coupling followed by hydrogenolytic cleavage of the resulting oxametallacycle, as corroborated by ESI−MS analysis.
Economic growth and crime against small and medium sized enterprises in developing economies

Several studies have explored the relationship between economy-level crime rates or individual-level crime and economic growth. However, few studies have examined the relationship between economic growth and crime against firms. This study uses data for about 12,000 firms in 27 developing countries and finds that economic growth is negatively associated with crime. This relationship is stronger for small and medium firms than large firms. The study also explores several economy-wide factors and their influence on the growth-crime relationship for small and medium enterprises. The results are robust to various sensitivity checks.
Spectral zeta functions of fractals and the complex dynamics of polynomials

We obtain formulas for the spectral zeta function of the Laplacian on symmetric finitely ramified fractals, such as the Sierpinski gasket, and a fractal Laplacian on the interval. These formulas contain a new type of zeta function associated with a polynomial (rational functions also can appear in this context). It is proved that this zeta function has a meromorphic continuation to a half-plane with poles contained in an arithmetic progression. It is shown as an example that the Riemann zeta function is the zeta function of a quadratic polynomial, which is associated with the Laplacian on an interval. The spectral zeta function of the Sierpinski gasket is a product of the zeta function of a polynomial and a geometric part; the poles of the former are canceled by the zeros of the latter. A similar product structure was discovered by M.L. Lapidus for self-similar fractal strings.
Solar-wind dependence of the diurnal temperature variation in the thermosphere

The ratio r = Tmax/Tmin of the maximum to the minimum exospheric temperature considered on a global scale was derived by means of static models using the densities obtained from the atmospheric drag of three low-inclination satellites. It is found that r varies with the solar cycle, lagging more than a year behind the variations of the 10.7-cm solar flux; on the other hand, the variations of r are in phase with K¯p, which is obtained by averaging the planetary geomagnetic index Kp over the whole year. The obvious conclusion is that, in the mechanism of the diurnal temperature variation in the thermosphere, the solar wind may be at least as important as, if not more important than, solar EUV. No appreciable lag is found in the variation of the minimum nighttime temperature when compared with the variations of the 10.7-cm solar flux.
Explorations in Organic Chemistry Leading to the Total Synthesis of (±)-Gelsemine

The total synthesis of (±)-gelsemine (1) is described. A defining phase of the effort involved recourse to a strategic oxetane ring (see compound 25). It was constructed anticipating an intramolecular displacement of the carbon (C17)−oxygen (O4) bond (see product 48). A key intermediate in the stereospecific elaboration of the oxetane linkage was enone 22, which was susceptible to two β-face attacks leading to 24 and, thence, 25. Three sigmatropic rearrangements were employed in building the bridgehead (C20) and the spiroanilide (C7) quaternary centers en route to gelsemine.
Photoionization and electron–ion recombination of Cr I

Abstract Using the unified method, the inverse processes of photoionization and electron–ion recombination are studied in detail for neutral chromium, ( Cr I + h ν ↔ Cr II + e ), for the ground and excited states. The unified method based on close-coupling approximation and R-matrix method (i) subsumes both the radiative recombination (RR) and dielectronic recombination (DR) for the total rate and (ii) provides self-consistent sets of photoionization cross sections σ PI and recombination rates α RC . The present results show in total photoionization of the ground and excited states an enhancement in the background at the first excited threshold, 3 d 4 4 s 5 D state of the core. One prominent phot-excitation-of-core (PEC) resonance due to one dipole allowed transition ( 6 S - 6 P o ) in the core is found in the photoionization cross sections of most of the valence electron excited states. Structures in the total and partial photoionization, for ionization into various excited core states and ground state only, respectively, are demonstrated. Results are presented for the septet and quintet states with n ≤ 10 and l ≤ 9 of Cr I. These states couple to the core ground state 6 S and contribute to the recombination rates. State-specific recombination rates are also presented for these states and their features are illustrated. The total recombination rate shows two DR peaks, one at a relatively low temperature, at 630 K, and the other around 40,000 K. This can explain existence of neutral Cr in interstellar medium. Calculations were carried out in LS coupling using a close-coupling wave function expansion of 40 core states. The results illustrate the features in the radiative processes of Cr I and provide photoionization cross sections and recombination rates with good approximation for this astrophysically important ion.
Notes on SU(3) structures in type IIB supergravity

We study solutions of type IIB supergravity with an SU(3) structure group and four dimensional Poincare invariance and present relations among the bosonic fields which follow from the supersymmetry variations. We make explicit some results which also follow from the more general case of an SU(2) structure and give some short comments applicable to general supersymmetric solutions. We also provide simplified relations appropriate for duals of gauge theory renormalization group flows, and use these to derive the supergravity solution for a bound state of (p, q)5-branes and D3-branes.
Cyclization/hydrosilylation of functionalized 1,7-dienes to form substituted six-membered carbocycles

Abstract The cationic palladium complex (phen)Pd(Me)(OEt 2 ) + BAr 4 − [phen = 1,10-phenanthroline; Ar = 3,5-C 6 H 3 (CF 3 ) 2 ] catalyzed the cyclization/hydrosilylation of functionalized 1,7-dienes to form silylated cyclohexanes in good yield and with moderate to good trans-selectivity.
Statistical moments based methods for detecting sub-pixel target tracks in large image sequences

This paper reviews and compares the performance of several methods to detect target tracks in image sequences. The targets are assumed to be sub-pixel or not resolved by the imaging system, and moving over a static background. To process the resulting large amount of data requires simple, fast and robust processing methods to quickly find and display tracks of moving targets in a single image. An object moving through a pixel in a scene will momentarily perturb the pixel intensity signal, introducing a change of both skewness and kurtosis in the intensity histogram relative to an undisturbed pixel. Numerical experiments show that for Gaussian and Poisson distributed system noise higher order moments (<2) perform better than second order detectors.