cssi/SciSciGPT-SciSciNet huggingface dataset:
Controlled Drug Delivery to the Joints by Enzymatically Degradable Microspheres

An intra-articular polymeric controlled release system was developed that is tailored to, and responsive to, the intensity of joint inflammation. Microspheres composed of the naturally occurring polyelectrolytes, gelatin and chondroitin sulfate, were synthesized by complex coacervation and the kinetics of release of encapsulated 14 C-catalase was evaluated in vitro in the presence of inflammatory and non-inflammatory human joint fluids. The relative activity of gelatinase, a metalloprotease enzyme, was quantified in each of the joint fluids. Rate of degradation of the microspheres, and consequent release of 14 C-catalase, was found to parallel the relative gelatinase activities in the joint fluids. Furthermore, various methods of crosslinking were found to affect the kinetics of microsphere degradation in the fluids. A catalase loading level of up to 28% was achieved, and the encapsulated catalase was found to retain up to 58 % of its biological activity.
Advances in Radiative Transfer Modeling in Support of Satellite Data Assimilation

Development of fast and accurate radiative transfer models for clear atmospheric conditions has enabled direct assimilation of clear-sky radiances from satellites in numerical weather prediction models. In this article, fast radiative transfer schemes and their components critical for satellite data assimilation are summarized and discussed for their potential applications in operational global data assimilation systems. The major impediments to the fast radiative transfer schemes are highlighted and a call is made for broader community efforts to develop advanced radiative transfer components that can better handle the scattering from atmospheric constituents (e.g., aerosols, clouds, and precipitation) and surface materials (e.g., snow, sea ice, deserts).
Organic derivatives of closo-boranes: a new class of liquid crystal materials

Abstract closo-Boranes and heteroboranes have been investigated as structural elements for liquid crystals. This paper reviews our progress to date in developing structure-property relationships for these boron cluster mesogens and assesses the effects of both steric and electronic influences on the liquid crystal behavior. The observation that nematic phases are favored over smectic phases is attributed principally to the steric effect of the clusters. Electronic and stereoelectronic effects can lead to materials exhibiting unusual properties. For example, compounds may exhibit high refractive indices yet low birefringence, they may be UV-transparent or, in some cases, exhibit strong charge transfer interactions with π-aromatic systems.
Foreign ownership, sales to multinationals and firm efficiency: the case of Brazil, Morocco, Pakistan, South Africa and Vietnam

Using a one-step stochastic frontier model for five developing countries, this article shows that foreign firms benefit from a better investment climate, which significantly explains why they are more efficient than local firms. This article uses the share of each firm's sales to multinationals located in the country to assess the importance of vertical spillovers, while controlling for the direct impact of the investment climate on efficiency. The results show that firms, particularly small local firms, selling more of their production to multinationals are more efficient, highlighting the presence of vertical spillovers through backward linkages.
A Hyperheuristic Approach to Select Enumeration Strategies in Constraint Programming

This work is focused on the Enumeration phase of Constraint Programming to solve Constraint Satisfaction Problems, an enumeration strategy is constituted by a variable selection heuristic and a value selection heuristic. A suitable definition and use of the enumeration strategy can strongly improve the resolution process. In order to select the enumeration stretegies dynamically here we present a hyperheuristic approach using information about the search process. We report encouraging results where our combination of strategies outperforms the use of individual strategies
Decomposition of Algebraic Functions

Functional decomposition?whether a functionf(x) can be written as a composition of functionsg(h(x)) in a non-trivial way?is an important primitive in symbolic computation systems. The problem of univariate polynomial decomposition was shown to have an efficient solution by Kozen and Landau (1989). Dickerson (1987) and Gathen (1990a) gave algorithms for certain multivariate cases. Zippel (1991) showed how to decompose rational functions. In this paper, we address the issue of decomposition of algebraic functions. We show that the problem is related to univariate resultants in algebraic function fields, and in fact can be reformulated as a problem ofresultant decomposition. We characterize all decompositions of a given algebraic function up to isomorphism, and give an exponential time algorithm for finding a non-trivial one if it exists. The algorithm involves genus calculations and constructing transcendental generators of fields of genus zero.
Statistical dynamics of the Royal Road genetic algorithm

Abstract Metastability is a common phenomenon. Many evolutionary processes, both natural and artificial, alternate between periods of stasis and brief periods of rapid change in their behavior. In this paper an analytical model for the dynamics of a mutation-only genetic algorithm (GA) is introduced that identifies a new and general mechanism causing metastability in evolutionary dynamics. The GA's population dynamics is described in terms of flows in the space of fitness distributions. The trajectories through fitness distribution space are derived in closed form in the limit of infinite populations. We then show how finite populations induce metastability, even in regions where fitness does not exhibit a local optimum. In particular, the model predicts the occurrence of “fitness epochs” — periods of stasis in population fitness distributions — at finite population size and identifies the locations of these fitness epochs with the flow's hyperbolic fixed points. This enables exact predictions of the metastable fitness distributions during the fitness epochs, as well as giving insight into the nature of the periods of stasis and the innovations between them. All these results are obtained as closed-form expressions in terms of the GA's parameters. An analysis of the Jacobian matrices in the neighborhood of an epoch's metastable fitness distribution allows for the calculation of its stable and unstable manifold dimensions and so reveals the state space's topological structure. More general quantitative features of the dynamics — fitness fluctuation amplitudes, epoch stability, and speed of the innovations — are also determined from the Jacobian eigenvalues. The analysis shows how quantitative predictions for a range of dynamical behaviors, that are specific to the finite population dynamics, can be derived from the solution of the infinite population dynamics. The theoretical predictions are shown to agree very well with statistics from GA simulations. We also discuss the connections of our results with those from population genetics and molecular evolution theory.
Suppressing resistance to low-skill migration

Just like any other trade activity, migration tends to generate gains to all parties involved, the migrants as well as the native population, if markets are well-functioning. But typically these gains tend to be rather small. However, when the labor market is mal-functioning, migration may exacerbate the imperfections in the market. Consequently, it could lead to losses to the host-country population, which can be quite sizable. An additional problem raised by migration is the toll it imposes on the welfare state. As a democracy, the host-country cannot exclude migrants from various entilement programs and public services. As a consequence, the modern welfare state could find it more and more costly to run its various programs when they attract low-income migrants. These considerations may help explain why there is strong resistance to migration. Consequently, to be able to benefit from migration, one may want to improve the functioning of the markets (with a compensation to wage earners that compete with unskilled migrants) and to downsize the scope of the state entitlement programs.
Non-perturbative solution of matrix models modified by trace-squared terms

Abstract We present a non-perturbative solution of large N matrix models modified by terms of the form g (Tr o 4 ) 2 , which add microscopic wormholes to the random surface geometry. For g g t the sum over surfaces is in the same universality class as the g = 0 theory, and the string susceptibility exponent is reproduced by the conventional Liouville interaction ∼ e α + o . For g = g t we find a different universality class, and the string susceptibility exponent agrees for any genus with Liouville theory where the interaction term is dressed by the other branch, e α − o . This allows us to define a double-scaling limit of the g = g t theory. We also consider matrix models modified by terms of the form gO 2 , where O is a scaling operator. A fine-tuning of g produces a change in this operator's gravitational dimension which is, again, in accord with the change in the branch of the Liouville dressing.
Bridging time and length scales in semiconductor process model development

The development of new semiconductor device materials is currently dominated by costly and time-consuming experimental investigations in which growth parameters are varied and correlated, ex situ, to device characteristics. Model-based process development has the potential to assist greatly in optimizing growth parameters and providing models that are suitable for use in in-situ process control. Researchers have used this approach sparingly, however, because robust, predictive models that describe the growth of semiconductor materials are neither well-developed nor validated. This situation is changing, however, due to the availability of high-resolution microscopy and improved modeling capabilities resulting from greatly increased computer power and more efficient numerical algorithms. The focus in this paper is on III-V semiconductor molecular beam epitaxy (MBE), which is the preferred technique for growing complex heterostructure device materials with many critical interfaces. The challenge is to understand the connection between macroscopic reactor conditions and microscopic film properties such as interface thickness and morphology.
The Exponential Mechanism for Social Welfare: Private, Truthful, and Nearly Optimal

In this paper we show that for any mechanism design problem with the objective of maximizing social welfare, the exponential mechanism can be implemented as a truthful mechanism while still preserving differential privacy. Our instantiation of the exponential mechanism can be interpreted as a generalization of the VCG mechanism in the sense that the VCG mechanism is the extreme case when the privacy parameter goes to infinity. To our knowledge, this is the first general tool for designing mechanisms that are both truthful and differentially private.
Chiral electromagnetic waves at the boundary of optical isomers: Quantum Cotton-Mouton effect

We demonstrate that the boundary of two optical isomers with opposite directions of the gyration vectors (both parallel to boundary) can support propagation of electromagnetic waves in the direction perpendicular to the gyration axes (Cotton-Mouton geometry). The components of electromagnetic field in this wave decay exponentially into both media. The characteristic decay length is of the order of the Faraday rotation length for the propagation along the gyration axis. The remarkable property of the boundary wave is its chirality. Namely, the wave can propagate only in one direction determined by the relative sign of nondiagonal components of the dielectric tensor in contacting media. We find the dispersion law of the boundary wave for the cases of abrupt and smooth boundaries. We also study the effect of asymmetry between the contacting media on the boundary wave and generalize the results to the case of two parallel boundaries. Finally we consider the arrangement when the boundaries form a random network. We argue that at a point, when this network percolates, the corresponding boundary waves undergo quantum delocalization transition, similar to the quantum Hall transition.
Biofeedback in overactive bladder

Biofeedback is a form of learning or re-education in which the participant is retrained within a closed feedback loop. Information about one or more of the patient's normally unconscious physiologic processes is made available to the patient as a visual, auditory, or tactile signal. Objective responses are recorded on a polygraph trace so that they can be easily observed. Subjective responses are more difficult to monitor and it is often difficult to separate these effects of biofeedback from the placebo effect. Biofeedback has been successfully employed in cases of urinary incontinence due to detrusor instability. Indeed, a recent report has shown that biofeedback-assisted behavioral treatment is more effective than either oxybutynin or placebo in the treatment of urge and mixed urinary incontinence in older, community-dwelling women. Patients embarking on biofeedback need to be well motivated and intelligent enough to understand what is expected of them. The treatment is time consuming for both the patient and the operator, but the benefits of successful treatment include a reduction in morbidity and side effects associated with other therapies. Biofeedback can be employed as an adjunct to other forms of treatment, such as drug therapy, and is particularly useful in children.
The Organization of Public Service Provision

This paper addresses the question of how the responsibility for the delivery of social services, including health, education, and welfare programs, should be divided between state and central governments. We combine a random voting model and the incomplete contracts paradigm to formalize the trade-off between central and state responsibility for service delivery, and find that authority should rest with the party for whom the marginal impact of the service on re-election chances is greater. This in turn means that, other things equal, states with lower than average health, education, or welfare status should be given responsibility for service delivery, while authority in states with above average indicators should reside with the central government. Also, we show that there is no presumption that states that are given authority for service delivery should necessarily be granted expanded tax authority.
Spare Parts Requirements for Space Missions with Reconfigurability and Commonality

The logistics resources (in the form of spare parts) for future exploration missions to the Moon and Mars can have significant mass and volume requirements. In this study it is shown that reconfigurable or common parts, that allow use of the same component in dierent mission elements, can be a means of reducing the required number of spares. A model for determining the system availability as a function of spares level is developed for a mission that utilizes elements with reconfigurable or common parts. An explicit consideration of the operating scenario is made which allows for using components from elements that are not operating at a given time. A Mars surface exploration mission is used to illustrate the application of this model. It is shown, for the specific example studied in the analysis, that the same level of system availability can be achieved with 33% - 50% fewer spares if the parts are reconfigurable or common across dierent mission elements.
Contribution of the mantle to the lunar asymmetry

Evidence of three kinds indicates a lunar compositional asymmetry: mare basalts are much more abundant on the near side; the incompatible rich KREEP component is mainly observed in near-side soils; and materials on the far side are less dense than those of the near side, as indicated by the 2-km offset between the center of mass and center of figure. Recent models to explain the 2-km offset are based on near side-far side differences in the thickness of crustal units. The most widely discussed model calls for a thickness of anorthosite of about 24 km greater on the far side than on the near side, but no satisfactory method of generating such a large difference has been proposed. It is suggested that much of the offset reflects longitudinal differences in mantle composition, primarily resulting from earlier (or more rapid) crystallization of the magma ocean on what is not the far-side hemisphere. As a result, the far-side mantle would be more magnesian and thus less dense than the near-side mantle.
Programming systems and languages: a historical survey

Twenty years ago, in 1943, there were no Electronic computers. Ten years ago, in 1953, a large number of Electronic calculators were in use, but the general purpose stored program electronic computer was still quite rare. The Coincident Current Magnetic Core memory which finally provided both reliability and speed at reasonable cost had only just been developed, and was still a laboratory device. A number of specially designed, mostly one of a kind, computers were in operation at Universities and government research centers. Commercially, a few Univac I computers had been delivered and were operating with great reliability at rather low speed. A few IBM 701's provided high speed but with very poor reliability. In 1953 most computing was being done by the Card-Programmed Calculator, an ingenious mating of an Electromechanical Accounting Machine with an Electronic Calculating Punch.
Analysis of large-scale tests for AP-600 passive containment cooling system

Abstract All next-generation light water reactors utilize passive systems to remove heat via natural circulation and are significantly different from past and current nuclear plant designs. One unique feature of the AP-600 is its passive containment cooling system (PCCS), which is designed to maintain containment pressure below the design limit for 72 h without action by the reactor operator. During a design-basis accident (DBA), i.e., either a loss-of-coolant or a main-steam-line break accident, steam escapes and comes in contact with the much cooler containment vessel wall. Heat is transferred to the inside surface of the steel containment wall by convection and condensation of steam and through the containment steel wall by conduction. Heat is then transferred from the outside of the containment surface by heating and evaporation of a thin liquid film that is formed by applying water at the top of the containment vessel dome. Air in the annular space is heated by both convection and injection of steam from the evaporating liquid film. The heated air and vapor rise as a result of natural circulation and exit the shield building through the outlets above the containment shell. All of the analytical models that are developed for and used in the COMMIX-1D code for predicting performance of the PCCS will be described. These models cover governing conservation equations for multicomponents single-phase flow, transport equations for the k − ɛ two-equation turbulence model, auxiliary equations, liquid-film tracking model for both inside (condensate) and outside (evaporating liquid film) surfaces of the containment vessel wall, thermal coupling between flow domains inside and outside the containment vessel, and heat and mass transfer models. Various key parameters of the COMMIX-1D results and corresponding AP-600 PCCS experimental data are compared and the agreement is good. Significant findings from this study are summarized.
Reductive alkylations involving 2°- and 3°-enolyl adduct radicals

Abstract Reductive tert-butylation of electronegatively substituted alkenes is readily achieved in Me2SO by reaction with excess t-BuHgCl/Et3SiH. Reactivity studies indicate that towards t-Bu s-cis enones are more reactive than the s-trans conformers.
THE CLUSTERING PROPERTIES OF THE FIRST GALAXIES

We study the clustering properties of the first galaxies formed in the universe. We find that, due to chemical enrichment of the interstellar medium by isolated Population III stars formed in mini-halos at redshift z {approx_gt} 30, the (chronologically) first galaxies are composed of metal-poor Population II stars and are highly clustered on small scales. In contrast, chemically pristine galaxies in halos with mass M {approx} 10{sup 8} M{sub sun} may form at z < 20 in relatively underdense regions of the universe. This occurs once self-enrichment by Population III in mini-halos is quenched by the buildup of an H{sub 2} photodissociating radiative background in the Lyman-Werner bands. We find that these chemically pristine galaxies are spatially uncorrelated. Thus, we expect that deep fields with the James Webb Space Telescope (JWST) may detect clusters of chemically enriched galaxies but individual chemically pristine objects. We predict that metal-free galaxies at 10 {approx}< z {approx}< 15 have surface densities of about 80 arcmin{sup -2} and per unit redshift but most of them will be too faint even for JWST. However, the predicted density makes these objects interesting targets for searches behind lensing clusters.
Quantitative validation of a deformable cortical surface model

Accurate reconstruction of the human cerebral cortex from magnetic resonance (MR) images is important for brain morphometric analysis, image-guided surgery, and functional mapping. Previously, we have implemented a cortical surface reconstruction method that employs fuzzy segmentation, isosurfaces and deformable surface models. The accuracy of the fuzzy segmentation has been well-studied using simulated brain images. However, global quantitative validation of the cortical surface model has not been feasible due to the lack of a true representation of the cortical surface. In this paper, we have alternately validated the deformable surface model used in one cortical surface reconstruction method by using a metasphere computational phantom. A metasphere is a mathematically defined three-dimensional (3-D) surface that has convolutions similar to the cortex. We simulated 500 image volumes using metaspheres with various numbers and degrees of convolutions. Different levels of Gaussian noise were also incorporated. Quantification of the differences between the reconstructed surfaces and the true metasphere surfaces provides a measure of the deformable model accuracy in relation to the properties of the modeled object and data quality.
Evaluation of image artifact produced by optical coherence tomography of retinal pathology.

Purpose To determine the frequency and type of optical coherence tomography (OCT) fast macular thickness map (FMTM) scan artifacts, and whether these artifacts depend on patient diagnosis, demographics, and ocular therapy. Design Retrospective observational case series. Methods Records from patients who underwent an ophthalmologic evaluation by a member of the Duke University Eye Center vitreoretinal faculty and had an OCT scan produced by the FMTM protocol between July 7, 2003 and July 31, 2003 were reviewed. The relationships between OCT scan artifacts and ocular diagnosis, ocular treatment, and patient demographics were determined. Logistic regression was used to relate OCT scan artifacts simultaneously with ocular diagnosis and treatment. Results Scans from 171 eyes were analyzed. Retinal scan artifacts, though not observed in normal eyes, were identified frequently in eyes with macular pathology ( P = .049). Artifacts were observed in 43.2% of all scans, and of these, an erroneous retinal thickness measurement was obtained in 62.2%. Six types of OCT surface map artifacts were observed. Of these, inner and outer retinal misidentification, degraded image artifact, and "off center" artifact were significantly associated with central thickness calculation errors ( P P = .002, .022, and Conclusion Optical coherence tomography scan artifacts are seen surprisingly frequently, adversely affect retinal thickness measurements in a high proportion of cases, and are diagnosis-dependent. Recognition of these artifacts will improve retinal thickness measurement accuracy, and will prevent faulty treatment decisions that are based on inaccurate retinal thickness measurements.
THE REDSHIFT SEARCH RECEIVER OBSERVATIONS OF 12CO J = 1 → 0 IN 29 ULTRALUMINOUS INFRARED GALAXIES

We present 12 CO J = 1 → 0 observations of ultraluminous infrared galaxies (ULIRGs) obtained using the Redshift Search Receiver (RSR) on the 14-m telescope of the Five College Radio Astronomy Observatory. The RSR is a novel, dual-beam, dual-polarization receiver equipped with an ultrawideband spectrometer backend that is being built as a facility receiver for the Large Millimeter Telescope. Our sample consists of 29 ULIRGs in the redshift range of 0.04-0.11, including 10 objects with no prior 12 CO measurements. We have detected 27 systems (a detection rate of 93%), including 9 ULIRGs that are detected in CO for the first time. Our study has increased the number of local ULIRGs with CO measurements by ∼ 15%. The CO line luminosity L ′, correlates well with farinfrared luminosity LFIR, following the general trend of other local ULIRGs. However, compared to previous surveys we probe deeper into the low CO luminosity end of ULIRG population as a single study by including a number of CO faint objects in the sample. As a result, we find 1) a smoother transition between the ULIRG population and local QSOs in LFIR −L ′ (“star formation efficiency”)
Perfluoroalkenyl ethers of simple sterols

Abstract Base-catalyzed addition of simple sterols to perfluoroalkenes, to give a variety of perfluoroalkenyl steroidal ethers, has been investigated. The outcome of the reaction was dependent on the base used for deprotonation of sterols. With potassium hydride, a mixture of 1- and 2-perfluoroalkenyl steroidal ethers was obtained in a low yield, whereas with n-butyllithium, preferential formation of 1-perfluoroalkenyl steroidal ethers was achieved in high yields.
Equality of the Spectral and Dynamical Definitions of Reflection

For full-line Jacobi matrices, Schrodinger operators, and CMV matrices, we show that being reflectionless, in the sense of the well-known property of m-functions, is equivalent to a lack of reflection in the dynamics in the sense that any state that goes entirely to x = −∞ as t → −∞ goes entirely to x = ∞ as t → ∞. This allows us to settle a conjecture of Deift and Simon from 1983 regarding ergodic Jacobi matrices.
Localizing gravity on the triple intersection of 7-branes in 10D

It was recently proposed that our universe could naturally come to be dominated by 3-branes and 7-branes if the universe is ten-dimensional. In this paper, we explicitly demonstrate that gravity can be localized on the intersection of three 7-branes in AdS10 to give four-dimensional gravity. We derive the exact relations among the tensions of the branes, and show that they apply independently of the precise distribution of energy within the necessarily thickened branes. We demonstrate this with several technical sections showing a simple formula for the curvature tensor of a diagonal metric with isometries as well as for the curvature at a gravitational singularity. We also demonstrate a subtlety in applying Stoke's Theorem to this set-up.
Can enstatite meteorites form from a nebula of solar composition

Abstract Doubts have been expressed as to whether solar matter is sufficiently reducing to explain the minerals occurring in the enstatite chondrites and in the enstatite achondrites. Thermodynamic calculations on the stabilities of TiN, Si2N2O, CaS and silicon-bearing iron metal show that these substances can form under equilibrium conditions from a nebula of solar composition provided that the total pressure exceeds ~ 1 atm and that thermodynamic equilibria are frozen in at near-formation temperatures.
Modeling of the Electrogun Metal Vapor Plasma Discharge

The electrogun metal vapor plasma discharge is a new high-power pulsed device for producing vapors of different metals. The process employs electrode erosion to vaporize one of the discharge electrodes. The eroded metal vapor is subsequently ionized to form a dense plasma in which a high current discharge is sustained. The vapor plasma then exits the discharge where it can be used in the synthesis of novel materials or as an ignitor for electrothermal - chemical guns. A model for the electrogun discharge bore plasma flow, bore wall erosion, and simplified models for the cathode and anode regions are presented in this paper. The bore plasma flows under local thermodynamic equilibrium conditions and is weakly nonideal. Two electrogun shots involving different cathode materials (aluminum and titanium) are simulated. Results reveal the physics underlying the operation of the electrogun discharge. High pressures of the bore plasma result in thermal choking at bore exit. Cathode material erosion dominates over the bore wall erosion, thus ensuring a relatively pure metal vapor yield. The exit parameters of the electrogun are predicted and can be used as input boundary conditions for analysis of the external plasma jet flow.
A Novel Sperm-Delivered Toxin Causes Late-Stage Embryo Lethality and Transmission Ratio Distortion in C. elegans

The evolutionary fate of an allele ordinarily depends on its contribution to host fitness. Occasionally, however, genetic elements arise that are able to gain a transmission advantage while simultaneously imposing a fitness cost on their hosts. We previously discovered one such element in C. elegans that gains a transmission advantage through a combination of paternal-effect killing and zygotic self-rescue. Here we demonstrate that this element is composed of a sperm-delivered toxin, peel-1, and an embryo-expressed antidote, zeel-1. peel-1 and zeel-1 are located adjacent to one another in the genome and co-occur in an insertion/deletion polymorphism. peel-1 encodes a novel four-pass transmembrane protein that is expressed in sperm and delivered to the embryo via specialized, sperm-specific vesicles. In the absence of zeel-1, sperm-delivered PEEL-1 causes lethal defects in muscle and epidermal tissue at the 2-fold stage of embryogenesis. zeel-1 is expressed transiently in the embryo and encodes a novel six-pass transmembrane domain fused to a domain with sequence similarity to zyg-11, a substrate-recognition subunit of an E3 ubiquitin ligase. zeel-1 appears to have arisen recently, during an expansion of the zyg-11 family, and the transmembrane domain of zeel-1 is required and partially sufficient for antidote activity. Although PEEL-1 and ZEEL-1 normally function in embryos, these proteins can act at other stages as well. When expressed ectopically in adults, PEEL-1 kills a variety of cell types, and ectopic expression of ZEEL-1 rescues these effects. Our results demonstrate that the tight physical linkage between two novel transmembrane proteins has facilitated their co-evolution into an element capable of promoting its own transmission to the detriment of organisms carrying it.
Perturbative Quantum Field Theory

This talk introduces perturbative quantum field on a heuristic level. It is directed at an audience familiar with elements of quantum mechanics, but not necessarily with high energy physics. It includes a discussion of the strategies behind experimental tests of fundamental theories, and of the field theory interpretations of these tests.
Reaction of alcohols (via the Mitsunobu reaction) and alkyl halides with chiral selone derivatizing agents

Abstract Coupling of a selone chiral derivatizing agent (CDA) to d , l -alkyl halides gives Se-alkylated adducts in yields ranging from 76–97%. Reaction of d , l -alcohols with the selone CDAs via the Mitsunobu reaction has given rise to Se-alkylated adducts in yields ranging from 82–92%. Examination of the 77 Se NMR spectra of the resulting diastereomeric adducts indicates that discrimination of remotely disposed chiral centers is possible using this technique.
The Beveridge–Nelson decomposition in retrospect and prospect

Abstract Beveridge and Nelson [Beveridge, Stephen, Nelson, Charles R., 1981. A new approach to decomposition of economic time series into permanent and transitory components with particular attention to measurement of the ‘business cycle’. Journal of Monetary Economics 7, 151–174] proposed that the long-run forecast is a measure of trend for time series such as GDP that do not follow a deterministic path in the long run. They showed that if the series is stationary in first differences, then the estimated trend is a random walk with drift that accounts for growth, and the cycle is stationary. In contrast to linear de-trending, the smoother of Hodrick and Prescott (1981) and Hodrick and Prescott [Hodrick, Robert, Prescott, Edward C., 1997. Post-war US business cycles: An empirical investigation. Journal of Money Credit and Banking 29 (1), 1–16] and the unobserved components model of Harvey, [Harvey, A.C., 1985. Trends and cycles in macroeconomic time series. Journal of Business and Economic Statistics 3, 216–227]. Watson [Watson, Mark W., 1986. Univariate detrending methods with stochastic trends Journal of Monetary Economics 18, 49–75] and Clark [Clark, Peter K., 1987. The cyclical component of US economic activity. The Quarterly Journal of Economics 102 (4), 797–814], the BN decomposition attributes most variation in GDP to trend shocks while the cycles are short and brief. Since each is an estimate of the transitory part of GDP that will die out, it seems natural to compare cycle measures by their ability to forecast future growth. The results presented here suggest that cycle measures contain little if any information beyond the short-term momentum captured by BN.
Three-Dimensional Flow Pattern Upstream of a Surface-Mounted Rectangular Obstruction

A three-dimensional TEACH-like computer code is developed and employed to study the flow phenomena upstream of a rectangular obstruction placed in a two-dimensional turbulent boundary layer. Satisfactory comparison is obtained with the experimental results of Blair (1984, 1987). All the computed flow patterns are similar to the one-vortex model of Eckerle and Langston (1986). The four-vortex model reported by Baker (1980) and Hunt et al (1978) cannot be found in any of the calculations.
Use of a digital/analog arithmetic unit within a digital computer

A novel approach to arithmetic operations in digital computers is described which combines digital and analog techniques. This is accomplished by using parallel-serial interconnections of digital/analog converters. The interconnections are under stored program control and are effected by selecting multiplexers which route the analog signals to perform various arithmetic operations. The final analog signal, which is the result of the computation is converted to digital form by means of an analog/digital converter.Because of the extreme parallel nature of D/A Arithmetic, high computational speeds are attained, although all the circuitry is operating slowly by present digital computer standards. Using present techniques the analog nature of the computation limits the accuracy to four or five significant decimal figures. Therefore, the D/A Arithmetic Unit could not replace the arithmetic unit presently in digital computers, but could be used to solve problems or parts of problems that do not require extreme accuracy.
Fare Pricing Elasticity, Subsidies, and Demand for Vanpool Services

Practitioners of transportation demand management consider pricing a crucial determinant of vanpool market demand. Publicly sponsored programs stress the significance of fare pricing and subsidies as key tools for increasing ridership. This paper considers the use of discrete choice modeling techniques to investigate the effects of fares and fare subsidies on the demand for vanpool services. With the use of employer and employee data from the 1999 survey of the commute trip reduction program of the Puget Sound region (Washington), a conditional discrete choice model is built to analyze the choice of vanpool services, with competing means of transportation as a function of various socioeconomic characteristics. The predicted value of the direct elasticity is -0.73; a 10% increase in vanpool price is associated with a 7.3% decrease in its demand and van-pool demand is relatively inelastic with respect to fare changes. For trips shorter than 30 mi, the individual elasticities are equivalent to the aggregate ...
Characterization of the Dynamical Response of a Micromachined G-Sensor to Mechanical Shock Loading

Squeeze film damping has a significant effect on the dynamic response of microelectro-mechanical system (MEMS) devices that employ perforated microstructures with large planar areas and small gap widths separating them from the substrate. Perforations can alter the effect of squeeze film damping by allowing the gas underneath the device to easily escape, thereby lowering damping. By decreasing the size of the holes, damping increases and the squeeze film damping effect increases. This can be used to minimize the out-of-plane motion of the microstructures toward the substrate, thereby minimizing the possibility of contact and stiction. This paper aims to explore the use of the squeeze film damping phenomenon as a way to mitigate shock and minimize the possibility of stiction and failure in this class of MEMS devices. As a case study, the performance of a G-sensor (threshold accelerometer) employed in an arming and fusing chip is investigated. The effect of changing the size of the perforation holes and the gap width separating the microstructure from the substrate are studied. A multiphysics finite-element model built using the software ANSYS is utilized for the fluidic and transient structural analysis. A squeeze film damping model, for both the air underneath the structure and the flow of the air through the perforations, is developed. Results are shown for various models of squeeze film damping assuming no holes, large holes, and assuming a finite pressure drop across the holes, which is the most accurate way of modeling. It is found that the threshold of shock that causes the G-sensor to contact the substrate has increased significantly when decreasing the holes size or the gap width, which is very promising to help mitigate stiction in this class of devices, thereby improving their reliability.
Uterus transplantation: the ethics of moving the womb.

Although currently in the early clinical research phase, the first successful birth of a child after uterus transplant is an early step toward another reproductive option for women with uterine factor infertility. Uterus transplantation uniquely brings together the fields of assisted reproductive te
A Scaleable Technique for the Measurement of Intrinsic MOS Capacitance with Atto-Farad Resolution

An on-chip capacitance measurement technique used for interline capacitances has been extended to MOS transistor capacitance measurements. The gate of the test transistor is connected to a reference capacitance made on the same chip. Small ac signals are applied to one of the transistor terminals successively. The magnitude of the ac voltages appearing on the gate node is measured indirectly. C/sub gd/,C/sub gs/ and C/sub gb/ are calculated accurately from the measured ac voltage and the reference capacitance value. It was found that C/sub gd/ and C/sub gs/, are measured completely free of parasitic capacitances resulting from both the internal on-chip circuit and external wiring. The on-chip circuit is simple and can easily be scaled down. These features insure this technique is the most suitable for the measurement of minimum-geometry transistors with atto-Farad-range resolution. It is shown that this technique has the ability to detect the capacitance difference which comes from the misalignment of source and drain metal connections. Measurements with this technique are used to first describe the short- and narrow-channel effects on MOS transistor capacitance.
Pruitt's Estimates in Banach Space

Pruitt’s estimates on the expectation and the distribution of the time taken by a random walk to exit a ball of radius r are extended to the infinite-dimensional setting. It is shown that they separate into two pairs of estimates depending on whether the space is type 2 or cotype 2. It is further shown that these estimates characterize type 2 and cotype 2 spaces.
Magnetic interactions, the renormalization group and color superconductivity in high density QCD

Abstract We investigate the effect of long range magnetic interactions on the renormalization group (RG) evolution of local Cooper pairing interactions near the Fermi surface in high density QCD. We use an explicit cut-off on momentum modes, with special emphasis on screening effects such as Landau damping, to derive the RG equations in a gauge invariant, weak coupling expansion. We obtain the Landau pole Δ∼μg −5 exp (−3π 2 / 2 g) , although the structure of our equations differs from previous results. We also investigate the gap equation, including condensates of higher angular momentum. We show that rotational invariance is unbroken at asymptotically high density, and verify that Δ is the correct value of the gap when higher modes are included in the analysis.
Monopulse Resolution of Interferometric Ambiguities

Ambiguities in interferometers with high angular accuracy must be resolved to achieve a practical system design. A new technique for ambiguity resolution is described and is based on monopulse circuitry used with the interferometric elements. The overall angular accuracy of the system is achieved by the interferometer; the angular accuracy of the monopulse subsystem is used to resolve interferometric ambiguities. An expression for the probability of correct ambiguity resolution is derived as a function of element size and monopulse accuracy which indicates that high probability of ambiguity resolution results when the size of the interferometric elements are a fraction of the interferometric baseline. Finally, a comparison between conventional monopulse and interferometric system designs is made for the three principal parameters, signal sensitivity, angular accuracy, and field of view, that dictate the appropriate choice for a particular application. Interferometric systems are more appropriate than monopulse systems for those applications in which angular accuracy and field of view are more important than signal sensitivity.
Email as spectroscopy: automated discovery of community structure within organizations

We describe a method for the automatic identification of communities of practice from email logs within an organization. We use a betweenness centrality algorithm that can rapidly find communities within a graph representing information flows. We apply this algorithm to an email corpus of nearly one million messages collected over a two-month span, and show that the method is effective at identifying true communities, both formal and informal, within these scale-free graphs. This approach also enables the identification of leadership roles within the communities. These studies are complemented by a qualitative evaluation of the results in the field.
Stable 4E-Dipyrrinones

Abstract Dipyrrinones formed by DBU and n -Bu 3 P-promoted condensation of 5- p -toluene-sulfonylpyrrolinones with pyrrole 2-aldehydes, gave high yields of product with predominantly the E -configuration when the aldehyde had a 5-carboethoxy group. The 4 E -dipyrrinones were readily purified by chromatography and were stable in solutions shielded from light.
ANGELS AT SINAI: EXEGESIS, THEOLOGY AND INTERPRETIVE AUTHORITY

This chapter is concerned with the role that angels are said to have played at Sinai during the revelation of the Law. Previous studies have established that some early Christian traditions emphasize that angels acted as mediators in the revelation of the Torah, while some rabbinic traditions emphasize the immediacy of the Sinai event, and evidence has been adduced of a polemical debate between Christians and Jews on this matter. In the chapter, some of the relevant material are revisited from a new perspective. First, the chapter situates the issue of angels at Sinai within the more general study of interpretive claims to authority. Second, it explores the Second Temple background to the debate, a background that has been noted before, but not examined in much detail. Third, the chapter considers several different exegetical strategies employed to counter the notion of angelically mediated revelation in some rabbinic traditions.Keywords: angels; Christian traditions; interpretive authority; rabbinic exegesis; rabbinic traditions; revelation; Second Temple; Sinai; Torah
Quasi-ballistic electron transport in as-produced and annealed multiwall carbon nanotubes

The electronic properties of multiwall carbon nanotubes (MWNTs) [1] have attracted much attention because they could lead to nano-sized devices [2–6]. To obtain optimal performance, it is desirable to utilize MWNTs of the highest purity and the best quality. Using chemical vapor deposition (CVD), MWNTs can be produced in large quantities at a low cost [7]. CVDproduced MWNTs, however, contain a considerable amount of structural defects due to their low temperature synthesis [7,8]. Since these defects act as scattering centers in electron transport and thus limit the electronic mean free path (EMFP), high-temperature annealing should lengthen the EMFP. This expectation is based on the previous experiments in which annealing eliminated structural defects in various carbon materials including nanotubes [8–10]. In this study we investigate how annealing affects the transport properties of CVDgrown MWNTs. To measure the EMFP of individual nanotubes, we submerged them into liquid mercury (Hg) and measured the variation in conductance [4]. We found that the EMFP is much longer in annealed nanotubes compared with that of as-produced ones. The annealed nanotubes show quasi-ballistic electronic transport with the EMFP reaching a few microns, even at room temperature. We started with soot consisting of CVD-produced MWNTs (10–20 nm diameter, 1–5 lm length, >95% purity; NanoLab, Inc.). Scanning electron microscopy (SEM, JSM-6700F, JEOL) showed nanotubes protruding from the edges of the soot sample (Fig. 1A). The annealing was done in argon (>99.9999% purity) at 2700 C for 30 min. The concentration of defects was estimated using thermogravimetric analysis (TGA, Pylis 1 TGA, Perkin–Elmer). Oxidation in carbon nanotubes begins at structural defects [11], and when nanotubes with many defects are subjected to an oxidative atmosphere, they begin to lose weight at a lower temperature than tubes with fewer defects. For the TGA measurements, the samples were dried at 105 C for 1 h, and heated to 800 C at 5 C/min in dry air at 30 ml/min. The oxidation starting point, defined as the temperature at which the weight is reduced by 5%, increased from 360 C to 560 C with annealing (Fig. 1B). This indicates that certain types of defects are eliminated by annealing at 2700 C. The conduction properties were measured in air at room temperature using a piezo-driven nanopositioning system (Fig. 2A) [12], which allowed gentle and reproducible contact between the sample, attached to the probe using silver paste, and the Hg counter electrode [4]. The mobile electrode (‘‘probe’’) was attached to the piezo-positioner with a displacement range of 20 lm (17PAZ005, MELLES GRIOT). The Hg was positioned below the mobile electrode. To make electrical contact between the sample and Hg, the probe was driven cyclically up and down with a peak-to-peak
Physics from vacuum alignment in a technicolor model

Abstract I describe a technicolor model (without walking) of all interactions up to energies of the order of 1000 TeV. The low-energy extended technicolor model has the CTSM form. But at intermediate energy scales, additional interactions are required to give the KM mixing. I discuss the characteristic flavor changing neutral current interactions arising from this flavor physics below 1000 TeV.