cssi/SciSciGPT-SciSciNet huggingface dataset:
The Polynomial Method for Random Matrices

We define a class of “algebraic” random matrices. These are random matrices for which the Stieltjes transform of the limiting eigenvalue distribution function is algebraic, i.e., it satisfies a (bivariate) polynomial equation. The Wigner and Wishart matrices whose limiting eigenvalue distributions are given by the semicircle law and the Marcenko–Pastur law are special cases. Algebraicity of a random matrix sequence is shown to act as a certificate of the computability of the limiting eigenvalue density function. The limiting moments of algebraic random matrix sequences, when they exist, are shown to satisfy a finite depth linear recursion so that they may often be efficiently enumerated in closed form. In this article, we develop the mathematics of the polynomial method which allows us to describe the class of algebraic matrices by its generators and map the constructive approach we employ when proving algebraicity into a software implementation that is available for download in the form of the RMTool random matrix “calculator” package. Our characterization of the closure of algebraic probability distributions under free additive and multiplicative convolution operations allows us to simultaneously establish a framework for computational (noncommutative) “free probability” theory. We hope that the tools developed allow researchers to finally harness the power of infinite random matrix theory.
Achieving nonvanishing stability regions with high-gain cheap control using H∞ techniques: the second-order case

Abstract This paper demonstrates how to use an asymptotically H ∞ -optimal controller to stabilize a second-order system subject to unknown disturbances such that the stability region does not vanish as the feedback gains increase. The high-gain feedback arises when one attempts to achieve the lowest achievable limit of the disturbance attenuation under the H ∞ design. This type of gain increase can cause the stability region to vanish if the disturbance contains nonlinear terms. The analysis using Lyapunov techniques derives a sufficient condition on the design parameters to prevent the stability region from vanishing. In addition to describing exact solutions for six different cases, the paper provides simulations to illustrate the results.
Estimating and testing intertemporal preferences: a unified framework for consumption, work and savings

Five waves of the Panel Study of Income Dynamics (PSID), 1985-1989 including both wealth supplements, are used to construct an intertemporal budget constraint for selected single headed households. A new functional form of the dual consumer profit function rationalizing consumption, labor supply and savings is specified, estimated and used to test commonly maintained separability hypotheses. Both consumption- labor and time separability are rejected. Cross-price Frisch elasticities are found not to equal zero and this in turns affects all estimates of consumption, labor supply and saving elasticities. This paper contains new results from a previous paper submitted to EconWPA 12/16/03.
The pharmacologic approach to airway clearance: Mucoactive agents

The term "mucoactive agent" refers to any medication used to improve the clearance of airway secretions. It is not synonymous with the word "mucolytic" as this strictly means a drug that decreases the viscosity of secretions. In many cases, decreased viscosity will adversely affect cough transport. For this reason many of the older mucolytic agents such as acetylcysteine are not effective for the therapy of lung disease and their use is not recommended. I review here the many classes of mucoactive agents and identify a number of medications with great promise for the treatment of chronic airway disease.
The influence of particle size and structure on the Mössbauer spectra of iron carbides formed during Fischer-Tropsch synthesis

Abstract A modeling routine which accounts for superparamagnetic relaxation, collective magnetic excitation, log-normal particle distribution, and quadrupole shift distribution was used to generate theoretical Mossbauer spectroscopic data, which were analyzed with a standard least-squares fitting routine. These spectra were used for comparison with published spectra of e and e' carbides. The results indicate that invariably, the Mossbauer spectra of small carbide particles exhibit relaxation effects, and proper analysis can only be achieved by collecting a series of spectra at different temperatures. In addition, a critical evaluation of the available Mossbauer parameters for e and e' carbides is presented along with equally feasible interpretations of these results.
Studies on the Preparation of 2-Indolyl Triflates and Related Compounds

Abstract Upon treatment with trifluoromethanesulfonic acid anhydride (triflic anhydride), oxindole (4) is converted into 1-(trifluoromethanesulfonyl)indol-2-y1 trifluoromethanesulfonate (10) in 70% yield. Some attempted reactions of 1-(trifluoromethanesulfonyl)indole (13), conveniently prepared by treating indole (12) with n-butyllithium and triflic anhydride, are described.
Accuracy of the thin-lens approximation in strong lensing by smoothly truncated dark matter haloes

The accuracy of mass estimates by gravitational lensing using the thin-lens approximation applied to Navarro–Frenk–White mass models with a soft truncation mechanism recently proposed by Baltz, Marshall and Oguri is studied. The gravitational lens scenario considered is the case of the inference of lens mass from the observation of Einstein rings (strong lensing). It is found that the mass error incurred by the simplifying assumption of thin lenses is below 0.5 per cent. As a byproduct, the optimal tidal radius of the soft truncation mechanism is found to be at most 10 times the virial radius of the mass model.
MULTI-PHOTON INTERFERENCE AND TEMPORAL DISTINGUISHABILITY OF PHOTONS

A number of recent interference experiments involving multiple photons are reviewed. These experiments include generalized photon bunching effects, generalized Hong-Ou-Mandel interference effects and multi-photon interferometry for demonstrations of multi-photon de Broglie wavelength. The multi-photon states used in these experiments are from two pairs of photons in parametric down-conversion. We find that the size of the interference effect in these experiments, characterized by the visibility of the interference pattern, is governed by the degree of distinguishability among different pairs of photons. Based on this discovery, we generalize the concept of multi-photon temporal distinguishability and relate it to a number of multi-photon interference effects. Finally, we make an attempt to interpret the coherence theory by multi-photon interference via the concept of temporal distinguishability of photons.
Simple yet accurate current copiers for low-voltage current-mode signal-processing applications

As pressures increase on VLSI designers to use a lower supply voltage of 3.3 V rather than the present 5 V, current-mode signal-processing techniques will surely become increasingly important and attractive. Numerous current copiers have been proposed. Among them, the copier with a negative feedback approach is the best candidate for low-voltage current-mode signal-processing applications. However, the copier using a positive-gain feedback amplifier achieves better accuracy at the cost of increasing circuit complexity and settling time. This paper presents an alternative circuit implementation of the negative feedback approach. The proposed current copier uses a negative-gain feedback amplifier which can be easily realized by a simple circuitry with high accuracy and faster settling time. Simulation results show that with the simple digital CMOS process the proposed copier can be realized with only three transistors, achieves a dynamic range from 300 to 550 μA with an accuracy of 0.1% and can be settled within 3 ns with a power supply of 3.3 V. Thus the copier is well suited to our low-voltage current-mode sensor array applications
Synthesis and structure of TlCuTiTe3

Abstract The new compound TlCuTiTe 3 has been synthesized from Tl 6 Te 4 and the corresponding elements and characterized by single-crystal X-ray diffraction methods. TlCuTiTe 3 crystallizes in the space group C 2b 2 − P 2 1 / m of the monoclinic system with two formula units in a cell of dimensions a = 8.409(8) A , b = 3.956(3) A, c = 10.261(8) A, β = 111.56(4)°, V = 317.5(4) A 3 ( T = 115 K). The two-dimensional structure comprises slabs of alternating pairs of Ti octahedra and Cu tetrahedra. The slabs are separated by Tl′ cations coordinated to Te 3 anions in a monocapped trigonal prismatic fashion. Whereas the structure of the individual slabs in TlCuTiTe 4 , is strikingly similar to those found in the related materials NaCuTiS 3 , NaCuZrSe 3 , and NaCuZrTe 3 , the packing of the slabs is different. Two-probe resistivity measurements indicate that TlCuTiTe 3 is a semiconductor.
Foam-like compression behavior of fibrin networks

The rheological properties of fibrin networks have been of long-standing interest. As such there is a wealth of studies of their shear and tensile responses, but their compressive behavior remains unexplored. Here, by characterization of the network structure with synchronous measurement of the fibrin storage and loss moduli at increasing degrees of compression, we show that the compressive behavior of fibrin networks is similar to that of cellular solids. A nonlinear stress–strain response of fibrin consists of three regimes: (1) an initial linear regime, in which most fibers are straight, (2) a plateau regime, in which more and more fibers buckle and collapse, and (3) a markedly nonlinear regime, in which network densification occurs by bending of buckled fibers and inter-fiber contacts. Importantly, the spatially non-uniform network deformation included formation of a moving “compression front” along the axis of strain, which segregated the fibrin network into compartments with different fiber densities and structure. The Young’s modulus of the linear phase depends quadratically on the fibrin volume fraction while that in the densified phase depends cubically on it. The viscoelastic plateau regime corresponds to a mixture of these two phases in which the fractions of the two phases change during compression. We model this regime using a continuum theory of phase transitions and analytically predict the storage and loss moduli which are in good agreement with the experimental data. Our work shows that fibrin networks are a member of a broad class of natural cellular materials which includes cancellous bone, wood and cork.
Testing Blend Scenarios for Extrasolar Transiting Planet Candidates. II. OGLE-TR-56

We reexamine the photometric and spectroscopic evidence available for the star OGLE-TR-56, recently discovered to harbor a giant planet presenting transits and orbiting with a period of 1.21 days. We investigate the possibility that the observational signatures reported might be the result of "blending" with the light of an eclipsing binary along the same line of sight. Using techniques developed earlier we perform fits to the light curve under a variety of blend configurations, subject to all observational constraints, and we infer further properties of these possible blends. We then carry out realistic end-to-end simulations based on those properties in order to quantify the spectral line asymmetries and radial velocity variations expected from such scenarios. We confront these calculations with the observations. The results from these models are clearly inconsistent with the measured radial velocity and bisector span variations, ruling out blends and confirming the planetary nature of the companion. The example of OGLE-TR-56 serves to illustrate the sort of tests that can and should be performed on transiting planet candidates to eliminate the possibility of "false positives" and, in particular, line-of-sight contamination from eclipsing binaries.
Crystal growth and magnetic properties of the new iridates Ln1−xNa1+xIrO4 (Ln = Gd–Er, Y; x = 0.04–0.25)

Abstract We report the single crystal structures and magnetic properties of a series of lanthanide-containing iridates, Ln 1− x Na 1+x IrO 4 (Ln = Gd–Er, Y; x = 0.04–0.26) grown from a mixed sodium and cesium hydroxide flux. The compounds crystallize in the hexagonal space group P -62 m (#189) with lattice parameters ranging from a = 9.3872(2)–9.4596(3) A and c = 3.1512(1)–3.2030(2) A and are structurally related to other iridium oxides. The oxidation state of iridium ranges from +4.08 (Gd) to +4.50 (Er). Magnetic susceptibility measurements reveal the existence of antiferromagnetic correlations below 15 K.
Endogenous transfers in the Prisoner's Dilemma game: An experimental test of cooperation and coordination

We test a two-stage compensation mechanism for promoting cooperation in Prisoner’s Dilemma games. Players first simultaneously choose binding non-negative amounts to pay their counterparts for cooperating, and then play the induced game knowing these amounts. In our games, all payment pairs consistent with mutual cooperation in subgame-perfect equilibrium transform these games into coordination games, with both mutual cooperation and mutual defection as Nash equilibria in the second stage. When endogenous transfer payments are not permitted, cooperation is much less likely. Mutual cooperation is most likely when the (sufficient) payments are identical, and it is also substantially more likely with payment pairs that bring the mutual-cooperation payoffs closer together. Both the Fehr–Schmidt and Charness–Rabin models predict that transfers that make final payoffs closer are preferred; however, they do not explain why equal transfers are particularly effective. Transfers are also effective in sustaining cooperation even when they are imposed and not chosen.
Studies of Asperity-Scale Plasma Discharge Phenomena

A combined experimental and computational simulation study of direct-current plasma discharge phenomena in small-length-scale geometries (<; 10 μm) is described. The primary goal is to study discharge breakdown characteristics in small-length-scale geometries as quantified by a modified Paschen breakdown curve and the quench characteristics in these discharges. A modified mesoscale friction tester apparatus is used for the experiments. A self-consistent nonequilibrium plasma model is used for the simulation studies. The model includes field-emission effects, which is a key process in determining small-length-scale breakdown behavior. The breakdown and quench curves obtained from the experiments and simulations showed the same general trends. Quantification of the heat fluxes from the simulations shows higher erosion at the cathode and a highly nonlinear heating behavior with applied overvoltages above the breakdown threshold.
Signal recovery and wavelet reproducing kernels

A class of signal recovery problems can be formulated as finding missing data at the finest scale of a discrete wavelet transform. A unique and stable recovery can be obtained by solving the regularized wavelet-reproducing equation. We show that this approach has close relations to unconstrained and constrained least-squares techniques and derive a family of regularizing operators adapted to the degrading operator. Experimental results present restored images using regularizing operators of this type. >
Resolved Spectroscopy of a Brown Dwarf Binary at the T Dwarf/Y Dwarf Transition

We report resolved near-infrared imaging and spectroscopic observations of the T8.5 binary WISEP J045853.90+643452.6AB obtained with Keck/NIRC2, Keck/OSIRIS, and the Keck Laser Guide Star Adaptive Optics system. These data confirm common proper and radial motion for the two components, and we see the first indications of orbital motion (mostly radial) for this system. H-band spectroscopy identifies both components as very late type brown dwarfs with strong H_2O and CH_4 absorption. The spectrum of WISE J0458+6434B also exhibits a compelling signature of NH_3 absorption over 1.52-1.54 μm when compared to the T9 dwarf UGPS J072227.51–054031.2. Comparison to T8-Y0 spectral standards and H-band spectral indices indicate classifications of T8.5 and T9.5 for these two components, approaching the boundary between the T dwarf and Y dwarf spectral classes.
Receiving system linearity requirements for HF radar

The sensitivity and consequent detection capability of an HF radar should not be compromised by nonlinearities occurring within the receiving systems. Two forms of nonlinear effects, known as intermodulation distortion and cross-modulation distortion, have the potential to limit radar sensitivity. An analysis showing that intermodulation distortion has the greater propensity to limit radar performance for a given large signal and noise environment is given. Further analysis is used to establish a quantitative relationship between the required third-order intercept point and relevant environmental and radar parameters. Adherence to this relationship in the design of an HF radar will ensure its desired immunity to nonlinear effects. >
A Gini decomposition analysis of inequality in the Czech and Slovak Republics during the transition

Disposable income inequality, as measured by the Gini coefficient and using the Family Budget Survey data, increased very little, and by a similar amount, from 1989 to 1993 in the Czech Republic and Slovakia. This surprising result is examined with an analysis of changes in the channels of redistribution and a Gini decomposition. We find that the sizeable increase in overall inequality due to changes in the wage earnings component is mitigated by changes in the tax and transfer components in both republics. As for the relative effects of government policies, changes in the transfer component contributed more than changes in the tax component to lowering the growth of inequality in the Czech Republic, while the reverse was true for Slovakia.
The Labor “Embodied” in Smith's Labor-Commanded Measure: A “Rationally Reconstructed” Legend

Nearly a half-century has passed since Ronald Meek (1956, p. 63) warned us that Adam Smith's notion of the labor commanded by a commodity in the marketplace is to be understood not as an expression of the “substance” of value, varying “directly with the quantity of social labor used to produce” the object, but rather as nothing more than a unit of value measure with no fixed relationship to the labor “embodied” in production. It was this distinction that he sought to fix in our minds with his memorable image of the magnet. Indeed, it is more than three times as long since John Stuart Mill (1848, p. 568) conveyed the same distinction with his particularly apt metaphor of “the thermometer and the fire.” Further, it is now forty years since Mark Blaug (1959), reminding us of that distinction, returned our attention to Smith's use of his measure as an expression of potential productive capacity (a view advanced earlier yet by Hla Myint 1948, pp. 20–21 and by Meek 1956, p. 65), but one that conveys a subjective dimension as well. Yet in spite of a now widespread concurrence in this reading, the “legend” that Smith's concept of labor commanded is to be understood as expressing, in some way, price ratios proportional to ratios of labor embodied in production remains remarkably resilient.
Microstructure evolution during spray rolling and heat treatment of 2124 Al

Abstract Spray rolling is a strip-casting technology that combines elements of spray forming and twin-roll casting. It consists of atomizing molten metal with a high velocity inert gas, quenching the resultant droplets in flight, and directing the spray between mill rolls. In-flight convection heat transfer from atomized droplets and conduction heat transfer at the rolls rapidly remove the metal's latent heat. Hot deformation of the semi-solid material in the rolls results in fully consolidated, rapidly-solidified strip. Spray rolling operates at a higher solidification rate than conventional twin-roll casting and is able to process a broader range of alloys at high production rates. A laboratory-scale strip caster was constructed and used to evaluate the interplay of processing parameters and strip quality for strips up to 200 mm wide and 1.6–6.4 mm thick. This paper examines microstructure evolution during spray rolling and explores how gas-to-metal mass flow ratio influences the microstructure and mechanical properties of spray-rolled 2124 Al. The influences of solution heat treatment and cold rolling on grain structure and constituent particle spheroidization are also examined.
The future of philosophy.

There is no sharp dividing line between science and philosophy, but philosophical problems tend to have three special features. First, they tend to concern large frameworks rather than specific questions within the framework. Second, they are questions for which there is no generally accepted method of solution. And third they tend to involve conceptual issues. For these reasons a philosophical problem such as the nature of life can become a scientific problem if it is put into a shape where it admits of scientific resolution. Philosophy in the 20th century was characterized by a concern with logic and language, which is markedly different from the concerns of earlier centuries of philosophy. However, it shared with the European philosophical tradition since the 17th century an excessive concern with issues in the theory of knowledge and with scepticism. As the century ends, we can see that scepticism no longer occupies centre stage, and this enables us to have a more constructive approach to philosophical problems than was possible for earlier generations. This situation is somewhat analogous to the shift from the sceptical concerns of Socrates and Plato to the constructive philosophical enterprise of Aristotle. With that in mind, we can discuss the prospects for the following six philosophical areas: (i) the traditional mind–body problem; (ii) the philosophy of mind and cognitive science; (iii) the philosophy of language; (iv) the philosophy of society; (v) ethics and practical reason; (vi) the philosophy of science. The general theme of these investigations, I believe, is that the appraisal of the true significance of issues in the philosophy of knowledge enables us to have a more constructive account of various other philosophical problems than has typically been possible for the past three centuries.
Driving to opportunity local rents, wages, commuting costs and sub-metropolitan quality of life

We examine variation in local rents, wage levels, commuting costs, household characteristics, and amenities within metropolitan areas, for 2071 areas covering the United States, by density and central-city status. We demonstrate the sensibility of estimating wage levels by workplace, not residence, and recover decentralized rent gradients that fall with commuting costs. We construct and map a willingness-to-pay index, which indicates the quality of life typical households receive from local amenities when households are similar, mobile, and informed. This index varies considerably within metros, and is typically high in areas that are dense, suburban, sunny, mild, safe, entertaining, and have elevated school-funding.
Computing feedback laws for linear systems with a parallel pieri homotopy

Homotopy methods to solve polynomial systems are well suited for parallel computing because the solution paths defined by the homotopy can be tracked independently. Both the static and dynamic load balancing models are implemented in C with MPI, adapting PHCpack written in Ada using gcc, and tested on academic benchmarks and mechanical applications. We studied the parallelization of Pieri homotopies to compute all feedback laws to control linear systems. To distribute the workload, we mapped the poset onto a tree. As the dimensions of the Pieri homotopies grow incrementally from the root to the leaves in the tree, we found the Pieri homotopies well suited for parallel computing.
The existence of small prime gaps in subsets of the integers

We consider the problem of finding small prime gaps in various sets . Following the work of Goldston–Pintz–Yildirim, we will consider collections of natural numbers that are well-controlled in arithmetic progressions. Letting qn denote the nth prime in , we will establish that for any small constant ϵ > 0, the set {qn | qn+1 - qn ≤ ϵ log n} constitutes a positive proportion of all prime numbers. Using the techniques developed by Maynard and Tao, we will also demonstrate that has bounded prime gaps. Specific examples, such as the case where is an arithmetic progression have already been studied and so the purpose of this paper is to present results for general classes of sets.
Grain boundary segregation and thermodynamically stable binary nanocrystalline alloys

A free-energy function for binary polycrystalline solid solutions is developed based on pairwise nearest-neighbor interactions. The model permits intergranular regions to exhibit unique energetics and compositions from grain interiors, under the assumption of random site occupation in each region. For a given composition, there is an equilibrium grain size, and the alloy configuration in equilibrium generally involves solute segregation. The present approach reduces to a standard model of grain boundary segregation in the limit of infinite grain size, but substantially generalizes prior thermodynamic models for nanoscale alloy systems. In particular, the present model allows consideration of weakly segregating systems, systems away from the dilute limit, and is derived for structures of arbitrary dimensionality. A series of solutions for the equilibrium alloy configuration and grain size are also presented as a function of simple input parameters, including temperature, alloy interaction energies, and component grain boundary energies.
Tandem Pummerer/Mannich Cyclization Cascade of α-Sulfinylamides as a Method To Prepare Aza-Heterocycles‡

A series of α-sulfinylenamides was conveniently prepared by the condensation of a primary amine with a ketone, followed by reaction of the resulting imine with ethylsulfenylacetyl chloride and subsequent oxidation with sodium periodate. When treated with p-TsOH, cyclization occurred to produce fused isoquinoline lactams by a mechanism that involves an initial Pummerer reaction followed by a subsequent cyclization of the resulting N-acyliminium ion onto the tethered aromatic ring. The isolation of a single diastereomer was rationalized in terms of a Nazarov-type 4π-electrocyclic reaction followed by π-cyclization onto the least hindered side of the N-acyliminium ion. Another method that was used to generate the α-acylthionium ion intermediate involved the reaction of bis(ethylsulfenylacetyl)acetamides with dimethyl(methyl)thiosulfonium tetrafluoroborate (DMTSF). Treatment of several bis-ethylsulfenylenamides with DMTSF delivered novel spiro-heterocycles as single diastereomers in good yield by a related pr...
Surface‐Protected Etching of Mesoporous Oxide Shells for the Stabilization of Metal Nanocatalysts

Nanoparticles of transition metals, particularly noble metals, are widely used in catalysis. However, enhancing their stability during catalytic reactions has been a challenge that has limited the full use of the benefits associated with their small size. In this Feature Article, a general "encapsulation and etching" strategy for the fabrication of nanocatalyst systems is introduced in which catalyst nanoparticles are protected within porous shells. The novelty of this approach lies in the use of chemical etching to assist the creation of mesopores in a protective oxide shell to promote efficient mass transfer to encapsulated metal nanoparticles. The etching process allows for the direct transformation of dense silica coatings into porous shells so that chemical species can reach the catalyst surface to participate in reactions while the shells act as physical barriers against aggregation of the catalyst particles. By using the surface-protected etching process, both yolk-shell and core― satellite type nanoreactors are synthesized and their utilization in liquid- and gas-phase catalysis is demonstrated. The thermal and chemical stability ofthe metallic cores during catalytic reactions is also investigated, and further work is carried out to enhance recyclability via the introduction of superparamagnetic components into the nanoreactor framework.
Predicting Web Page Status

The World Wide Web has become a key intermediary between producers and consumers of information. Web's linkage structure has been exploited by contemporary search engines to decrease the search cost for consumers while usually also rewarding the producers of higher status Web pages. In addition to influencing visibility and accessibility, in-links, as marks of recognition, accord status to a Web page. In this paper we show how Web page status may be predicted at least in part by page location and topic specificity. Moreover, we observe that the “philanthropic” contributions of a Web page---specifically, contributions of information brokerage function---are also good predictors of in-links. The observations are made in the presence of domain-and topic-specific effects. Interestingly, all of these features that may predict status are “local” to a given Web page and within the control of the owner/author of the page. This is in contrast to the “global” nature of Web linkage-based metrics such as in-link count that are derived as a result of downloading and indexing billions of pages. Because the linkage structure of the Web affects browsing, crawling, and retrieval, our results have implications for vertical and general search, business intelligence, and content management.
A framework for estimating willingness-to-pay to avoid endogenous environmental risks

This paper proposes a general empirical strategy to estimate willingness-to-pay (WTP) for exogenous risk mitigation when environmental risks are endogenous in protective actions and consumers are imperfectly informed about the ambient risk levels. The strategy consists of a set of survey techniques and the dummy endogenous variable model (Heckman, 1978) to control for correlation in unobserved errors that enter the WTP equation and the protection-decision equation. The method is applied to the non-market valuation survey data on arsenic contamination in drinking water. Our results indicate that the estimated WTPs are significantly higher for households without self-protective action. Our approach thus offers not only the correct welfare estimate for exogenous reduction of environmental risks, but also yields policy implications qualitatively much different from the conventional approach. We also estimate the welfare value of the policy to inform and educate the public about the arsenic risk simultaneously with public risk mitigation. The estimated welfare value is similar to, though slightly higher than, that of risk mitigation without information component. This occurs due to the competing effects of information dissemination and risk mitigation efforts.
Control of electric fields at the surface of p-n junctions

Both degradation resulting from ion migration and surface breakdown of p-n junctions depend strongly on electric field. These problems can be minimized or avoided by designing p-n junction devices so that the electric field at the surface is substantially lower than that within the body of the device. The shape, surface doping, and dielectric constant at the junction-surface interface have an appreciable influence on the electric field of the adjoining space charge layer. Using relaxation methods, solutions of Poisson's equation in two dimensions have been found which permit predictions of the surface fields as a function of surface geometry and dielectric coatings. Measurements of the surface field by probing the junctions are in good agreement with calculated values. This approach has led to the design of very high voltage p-n junction devices which exhibit body breakdown only. With the breakdown confined to the body of the device, the reverse power dissipation capability is not only predictable but significantly greater (typically 30 a at 1200 v for a 100 µsec pulse applied to a large area device) than that achievable with surface limited devices.
Synthesis of isoquinolines by palladium-catalyzed cyclization, followed by a Heck reaction

A variety of 4-(1-alkenyl)-3-arylisoquinolines have been prepared by the Pd(II)-catalyzed cyclization of 2-(1-alkynyl)benzaldimines, followed by alkenylation (Heck reaction) in good to excellent yields. The introduction of an ortho-methoxy group on the benzaldimine promotes the Pd-catalyzed cyclization and stabilizes the resulting Pd(II) intermediate improving the yields of the desired isoquinoline products.
Searching for prosperity

Abstract Quah's [1993a] transition matrix analysis of world income distribution based on annual data suggests an ergodic distribution with twin peaks at the rich and poor end of the distribution. Since the ergodic distribution is a highly non-linear function of the underlying transition matrix, it is estimated extremely noisily. Estimates over the foreseeable future are more precise. However, the Markovian assumptions underlying the analysis are much better satisfied with an analysis based on five-year transitions than one-year transitions. Such an analysis yields an ergodic distribution with 72% of mass in the top income category, but a prolonged transition, during which some inequality measures increase. The rosy ergodic forecast and prolonged transition arise because countries' relative incomes move both up and down at moderate levels, but once countries reach the highest income category, they rarely leave it. This is consistent with a model in which countries search among policies until they reach an income level at which further experimentation is too costly. If countries can learn from each other's experience, the future may be much brighter than would be predicted based on projecting forward the historical transition matrix.
The X-ray background-foreground galaxy cross-correlation: evidence for weak lensing?

A significant cross-correlation between the unre- solved X-ray background (XRB) at soft energies (0.5 to 2 keV) and foreground bright galaxies has now been reported in several studies. This cross-correlation has been interpreted in terms of a low redshift and a low luminosity active galactic nuclei (AGN) population, clustered similar to optically bright galaxies, as re- sponsible for the unresolved component of the XRB. In contrast to such a low redshift population, we suggest that a correlation between the unresolved XRB and bright optical galaxies can exist due to a high redshift population of X-ray emitting AGNs through weak lensing effects of low redshift large scale structure traced by foreground optical galaxies. We further investigate this possibility and suggest that a substantial fraction of the detected cross-correlation signal can arise from this scenario. The most likely explanation for the observed cross-correlation is that both a population of low redshift sources and a population of high redshift low luminous sources contribute through clustering and lensing effects, respectively. The exact weak gravitational lens- ing contribution to the detected signal can eventually be used to constrain cosmological parameters, foreground galaxy bias and, more importantly, models of high redshift X-ray emitting sources.
Confinement-induced Efimov resonances in Fermi-Fermi mixtures

A Fermi-Fermi mixture of $^{40}\text{K}$ and $^{6}\text{L}\text{i}$ does not exhibit the Efimov effect in a free space, but the Efimov effect can be induced by confining only $^{40}\text{K}$ in one dimension. Here the Efimov's three-body parameter is controlled by the confinement length. We show that the three-body recombination rate in such a system in the dilute limit has a characteristic logarithmic-periodic dependence on the effective scattering length with the scaling factor 22.0 and can be expressed by formulas similar to those for identical bosons in three dimensions. The ultracold mixture of $^{40}\text{K}$ and $^{6}\text{L}\text{i}$ in the one-dimensional--three-dimensional mixed dimensions is thus a promising candidate to observe the Efimov physics in fermions.
Adaptive sampling in hierarchical simulation

We propose an adaptive sampling methodology for hierarchical multi-scale simulation. The method utilizes a moving kriging interpolation to significantly reduce the number of evaluations of finer-scale response functions to provide essential constitutive information to a coarser-scale simulation model. The underlying interpolation scheme is unstructured and adaptive to handle the transient nature of a simulation. To handle the dynamic construction and searching of a potentially large set of finer-scale response data, we employ a dynamic metric-tree database. We study the performance of our adaptive sampling methodology for a two-level multi-scale model involving a coarse-scale finite element simulation and a fine-scale crystal plasticity-based constitutive law. Copyright © 2008 John Wiley & Sons, Ltd.
Patient selection for endovascular abdominal aortic aneurysm repair.

Because the US device trials were not randomized and were not matched for either anatomic or clinical criteria, we do not have Level I evidence of efficacy when endovascular treatments are compared with conventional aortic aneurysm (AAA) repair. Consequently, creating a clear, detailed algorithm for patient selection is not possible at this time. Instead, the decision to recommend one type of aneurysm repair over another is quite subjective, will vary from institution to institution, and is governed by a number of factors including anatomy, medical comorbidity, operator skills, and access to the devices. Ideally, the UK EndoVascular Aneurysm Repair, the Dutch DREAM Trial, and the French ACE Project, when completed, will provide more objective guidance for patient selection for each of the two procedures. These trials will not only compare the two operative approaches but will also evaluate best medical treatment in inoperable cases. Although I believe that young, healthy patients should have conventional repair, in properly selected patients, endovascular repair appears to be comparable to conventional repair, using rupture and death as end points within the first year after deployment. Because most patients, given a choice, would opt for the simpler, less invasive procedure, the fundamental question each of us must ask is how to select those most suitable for each of the two approaches given the limited data available. There are two distinct aspects to this recommendation—first, the physiologic condition of the patient, taking into account the patient’s life expectancy and his or her risk for conventional operation, and second, the anatomic factors that make endovascular repair possible or impossible, safe or risky. EARLY RESULTS OF ENDOVASCULAR ANEURYSM REPAIR Vascular surgeons are psychologically uncomfortable with palliation of aneurysms as opposed to cure, probably for good reason. Endovascular repair does not provide freedom from rupture in every case. Rupture has been reported in 25 patients in the AneuRx Trials (1,112 patients treated). In contrast to conventional repair, the need for lifelong surveillance is costly in dollars, staff resources, and patient time. Reintervention rates for a variety of problems are alarmingly high and over an intermediate time may result in longer cumulative hospital days and expenditures than conventional repair. The largest data set is the EUROSTAR registry begun in 1996. Voluntary reporting from 88 institutions deploying over 3,000 endografts indicates that the 30-day mortality rate is 2.1%, freedom from persistent endoleak at 18 months is 90%, the rate of rupture approaches 1.5% per year, and the conversion rate to open repair is 3% per year. The voluntary reporting requirements of this registry probably underestimate the incidence of complications, but the fact that the incidence of graft-related complications does not decrease over time is worthy of note and concern. Nonetheless, in an older, sicker population, any lack of certainty about a longterm cure after endovascular repair seems less relevant.
A model for mercury orificed hollow cathodes - Theory and experiment

The model outlined here provides a useful qualitative description of the basic physical processes taking place within a mercury orificed hollow cathode and can predict, to first order, important cathode operating parameters such as emission length and insert temperature. The analytical formulation of the model is based on the concept of an idealized "ion production region/' which is defined as the volume circumscribed by the emitting portion of the insert. The energy exchange mean free path for primary electrons is used as a criterion for determining the length Le of this region. An ion production region aspect ratio D/Le of 2 is suggested as a design criterion for minimizing the keeper voltage. The model accounts for electrons produced in the ion production region by surface emission and volume ionization. Surface and volume energy balances are used to predict plasma density and plasma potential in this region. An empirical relation is presented that can be used to estimate cathode internal pressure (a necessary input to the model) from the discharge current and cathode orifice diameter. Calculations based on the model are compared with experimental results.
Effective field theory of nuclear forces

Abstract The application of the effective field theory (EFT) method to nuclear systems is reviewed. The roles of degrees of freedom, QCD symmetries, power counting, renormalization, and potentials are discussed. EFTs are constructed for the various energy regimes of relevance in nuclear physics, and are used in systematic expansions to derive nuclear forces in terms of a number of parameters that embody information about QCD dynamics. Two-, three-, and many-nucleon systems, including external probes, are considered.
Online Discussion, Student Engagement, and Critical Thinking

Recent research into the merits of online discussion (computer-mediated communication) has shown that it promotes active learning behaviors and enhances learner outcomes. Scholars have also shown that, when instructors employ effective questioning and moderating skills, students can show higher levels of critical thinking in online discussion. In an investigation that merged and refined content analysis protocols in order to identify the effects of such factors as student GPA and type of course upon student engagement and student critical thinking, our findings substantiate a link between student interaction and critical thinking. When students engage one another in online discussions in a focused way, their capacity for reasoned discourse becomes more evident.
A framework for Military Bioethics

A widely accepted framework governs biomedical research and the practice of medicine in the civilian sector, but no such framework exists to guide the military in how it should treat its own personnel. Civilian bioethical principles are unsuitable because of fundamental differences between civilian and military core values. This paper proposes a framework for military bioethics. It begins by describing core military values, articulating how they differ from civilian goals and values, and explaining how these differences limit the ability of civilian bioethical principles to govern military biomedicine. The paper then puts forward a set of more appropriate principles for the military and discusses how these principles apply in three main areas of controversy within military bioethics: the use of military personnel as research subjects; the deployment use of biomedical agents; and the obligations of military physicians toward their own troops.
Coronal magnetic fields and energetic particles

Magnetic fields in coronal and interplanetary space play a critical role in the propagation and storage of energetic particles from the flare site to 1 AU. The current investigation is designed to determine if the detailed configuration of the coronal magnetic fields below 2.5 R⊙ has a measurable influence on the escape of particles to 1 AU, can account for the observed broad longitudinal distribution of proton flares, and can provide a realistic site for storage of energetic particles.
Computational forensic techniques for intellectual property protection

Computational forensic engineering (CFE) aims to identify the entity that created a particular intellectual property (IP). Specifically, our goal is to identify the synthesis tool or compiler which was used to produce a specific design or program. Rather than relying on watermarking content or designs, the generic CFE methodology analyzes the statistics of certain features of a given IP and quantizes the likelihood that a well known source has created it. In this paper, we describe the generic methodology of CFE and present a set of techniques that, given a set of compilation tools, identify the one used to generate a particular hardware/software design. The generic CFE approach has four phases: 1) feature and statistics data collection; 2) feature extraction; 3) entity clustering; and 4) validation. In addition to IP protection, the developed CFE paradigm can have other potential applications: optimization algorithm selection and tuning, benchmark selection, and source-verification for mobile code.
A Polycomponent Metal-Catalyzed Aliphatic, Allylic, and Benzylic Fluorination

A group effort: Reported is the title reaction using a polycomponent catalytic system involving commercially available Selectfluor, a putative radical precursor N-hydroxyphthalimide, an anionic phase-transfer catalyst (KB(C(6)F(5))(4)), and a copper(I) bis(imine). The catalyst system formed leads to monofluorinated compounds selectively (see example) without the necessity for an excess of the alkane substrate.
WIC Contract Spillover Effects

Under the U.S. Special Nutrition Program for Women, Infants, and Children (WIC) program, the three major infant formula manufacturers compete for WIC supply contracts, state by state. Policy makers have been puzzled by the question of why the contracted WIC price is substantially lower than the retail (non-WIC) price. Our explanation is that winning the WIC contract is extremely valuable to a manufacturer because of a spillover effect: The increased retail shelf-space that is dedicated to the WIC brand and the WIC logo increases non-WIC sales. We identify this effect by showing the variations in market shares of winning and losing firms that follow WIC contract changes. Immediately after the contract change, there is an immediate increase in the market share of the WIC contract winner and an equal drop in the loser’s share because of new WIC purchases. Then, over an extended period, the spillover effect increases the winner’s share and decreases the loser’s share as retailers shift shelf space from the loser to the winner.