cssi/SciSciGPT-SciSciNet huggingface dataset:
Three-component, one-flask synthesis of rhodanines (thiazolidinones).

5-(Z)-Alkylidene-2-thioxo-1,3-thiazolidin-4-ones (rhodanine derivatives) were prepared by reaction of in situ generated dithiocarbamates with recently reported racemic α-chloro-β,γ-alkenoate esters. This multicomponent sequential transformation performed in one reaction flask represents a general route to this medicinally valuable class of sulfur/nitrogen heterocycles. Using this convergent procedure, we prepared an analogue of the drug epalrestat, an aldose reductase inhibitory rhodanine.
Datación del "Príncipe" : inicio y culminación

This article establishes a new, more precise date for the completion of Machiavelli’s work on The Prince . Newly discovered documents in Florentine Archives from July 1515 reveal that Niccolo Machiavelli and his family were struggling to deal with an unexpected crisis that had befallen them in the previous several months. That crisis must have been none other than the failure of Machiavelli’s Prince to win favor with the book’s dedicatee, Lorenzo de’ Medici the Younger. The presentation of the book to Lorenzo can now be dated between 15 May 1515 and 3 July 1515, and probably toward the beginning of this period. And the final version of the text was completed at some point between 14 February 1515 and the presentation several months later.
Urban bias in price risk: the geography of food price distributions in low-income economies

The geography of agricultural marketing has important implications for the stochastic distribution of agricultural commodity prices. This article proposes that objective food price risk differs between rural and urban areas of infrastructure‐poor economies characterised by spatially concentrated patterns of foodgrains storage. This difference implies an urban bias having adverse welfare effects for peasants who seasonally switch between net food seller and net food buyer positions. Empirical analysis of rice price data from Madagascar suggests that price variability and skewness indeed differ between rural and urban areas in ways that adversely influence the relative welfare of rural peasants.
The distribution of matrix quotients

Cramer's inversion formula for the distribution of a quotient is generalized to matrix variates and applied to give an alternative derivation of the matrix t-distribution.
Treatment-Related Mortality in Patients with AL Amyloidosis Undergoing High-Dose Melphalan and Stem Cell Transplantation: Trend Over The Past 14 Years at a Single Institution

Abstract AL amyloidosis is caused by a clonal plasma cell dyscrasia and characterized by widespread, progressive amyloid deposition leading to multisystem organ failure and death. Aggressive treatment of AL amyloidosis with high dose intravenous melphalan followed by autologous stem cell transplantation (HDM/SCT) is effective in inducing hematologic and clinical remissions and in extending survival. However, HDM/SCT is a challenging treatment for patients with AL amyloidosis, given their multisystem disease. Morbidity and mortality are associated with all phases of HDM/SCT: during stem cell mobilization and collection, during post-treatment myelosuppression, and following hematopoietic engraftment. Between 7/1994 and 7/2008, 496 HDM/SCT were performed for patients with AL amyloidosis, (median age = 56, range 28–80), at Boston University Medical Center. Treatment-related mortality is defined as deaths during stem cell mobilization and collection phase as well as within 100 days after SCT. Overall treatment-related mortality was 12% (58/496). Of the 58 deaths, 11 (2%) occurred during the stem cell mobilization and collection phase of treatment, while 47 (9%) occurred within 100 days after SCT. Deaths during stem cell mobilization and collection were associated with cardiac arrhythmia (n=1), irreversible congestive heart failure (n=2), refractory hypotension (n=3), myocardial infarction due to small vessel amyloid disease (n=1), massive GI bleeding (n=3) and pulmonary embolism (n=1). There were 5 cardiac arrests leading to death during the stem cell infusion procedure. There were additional 42 deaths from D + 1 to D + 100 after SCT. Deaths during this period were associated with sepsis (33%), cardiac arrhythmia (26%) and hemorrhagic complications (10%). Overall treatment-related mortality was 14% (52/371) during the period from 7/1994 to 7/2004, the first decade of HDM/SCT for patients with AL amyloidosis at Boston University Medical Center. However, overall treatment-related mortality has considerably improved to 5% (6/125) during the period from 8/2004 to 7/2008. Improvement in treatment-related mortality rate over the past 14 years at this institution may be due to improved patient selection, to improvement in supportive care and to the cumulative experience of the treating multidisciplinary team physicians. In summary, HDM/SCT in AL amyloidosis presents unique clinical challenges, particularly because of the cardiovascular instability of patients and the risks of both thrombosis and bleeding. Both clinicians and patients who proceed with this aggressive form of therapy must be prepared for both the usual and unusual toxicities that may occur. Treatment-related mortality can be expected to be substantially greater at centers with limited experience with HDM/SCT for AL amyloidosis, compared with centers with much experience that focus on this complex disease.
Vortex burst model for the vortex lattice method

'Lin, K. C., "Dead-Reckoning in Distributed Interactive Simulation," Proceedings of the 3rd Annual Conference of the ChineseAmerican Scholars Association of Florida, Miami, FL, 1992, pp. 1-5. Hoffman, L. L., and Lin, K. C., "An Experimental Design for Detecting Optimal Simulated Flight Performance on Distributed Interactive Systems," Inst. for Simulation and Training, Univ. of Central Florida, TR IST-CR-93-16, Orlando, FL, May 1993.
Fragmentation, nucleation and migration of crystals and bubbles in the Bishop Tuff rhyolitic magma

The Bishop Tuff (USA) is a large-volume, high-silica pyroclastic rhyolite. Five pumice clasts from three early stratigraphic units were studied. Size distributions were obtained using three approaches: (1) crushing, sieving and winnowing (reliable for crystals >100 μm); (2) microscopy of ∼1 mm3 fragments (preferable for crystals 800 μm); concave-downward size distributions for whole crystals indicate late-stage growth with limited nucleation, compatible with the slow cooling of a large, gas-saturated, stably stratified magma body; (2) low-density (0·499 g cm −3), low-crystal content (6·63 wt.%) and few large crystals; the approximately linear size distribution reveals that nucleation was locally important, perhaps close to the walls; and (3) intermediate characteristics in all respects.The volumetric fraction of bubbles inversely correlates with the number of large crystals. This is incompatible with isobaric closed-system crystallisation, but can be explained by sinking of large crystals and rise of bubbles in the magma
SCANNING TUNNELING MICROSCOPY OF CARBON NANOTUBES AND NANOCONES

Abstract Tubular and conical carbon shell structures can be synthesized in the vapor phase. Very hot carbon vapor, after being deposited onto highly oriented pyrolytic graphite (HOPG), forms a variety of nanostructures, in particular single-shell tubes, multishell tubes, bundles of tubes, and cones. The structures were analyzed by scanning tunneling microscopy (STM) in UHV. Atomic resolution images show directly the surface atomic structures of the tubes and their helicities. A growth pathway is proposed for fullerenes, tubes, and cones.
Band coupling model of electron and hole mediated ferromagnetism in semiconductors: the case of GaN

Transition metal (TM) doped diluted magnetic semiconductors (DMSs) have many unique physical properties that can be used for magneto-optical and spintronic applications. The DMSs exhibit a wide range of magnetic ordering behavior. For example, Mn doped GaN can be either ferromagnetic or antiferromagnetic, depending on the Mn concentration, carrier density, or pressure. A unified band coupling model based on the p-d and d-d level repulsions between the TM and host elements are developed to explain the hole-induced ferromagnetism. We show that kinetic s-d coupling can be introduced through chemical ordering and strain, thus leading to electron-mediated ferromagnetism. Moreover, by using rare-earth elements (e.g., Gd) as magnetic dopants, the symmetry-allowed s-f coupling can also lead to a large splitting at the conduction band edge, producing electron-mediated ferromagnetism. Our model, therefore, provides a simple guideline for future band structure engineering of magnetic semiconductors.
Marketing Educational Improvements via International Partnerships under Brain Drain Constraints.

We study the dynamics in an educational partnership between a university and a developing region. We examine how the university achieves its goals to improve and advertise its offerings while recruiting a cohort of students from the developing region and maintaining a sustainable relationship with the region and its students. We show that mutually beneficial partnerships can arise, particularly when both the university and the region exhibit strong preferences toward cohort students returning to work at home. We further show that such partnerships can induce developing regions to invest in domestic opportunities for returning students.
Absolute Continuity and Convergence in Variation for Distributions of Functionals of Poisson Point Measure

General sufficient conditions are given for absolute continuity and convergence in variation of the distributions of the functionals on the probability space generated by a Poisson point measure. The phase space of the Poisson point measure is supposed to be of the form ${\mathbb{R}}^{+}\times{\mathbb{U}}$ , and its intensity measure to equal dt Π(du). We introduce the family of time stretching transformations of the configurations of the point measure. Sufficient conditions for absolute continuity and convergence in variation are given in terms of the time stretching transformations and the relative differential operators. These conditions are applied to solutions of SDEs driven by Poisson point measures, including SDEs with non-constant jump rate.
Synthesis and Control of Piezoelectric Resonant Actuation Systems with Buckling-Beam Motion Amplifier

Nonlinear dynamic model and control method are developed for a piezoelectric/buckling beam motion amplifier to operate as a resonant actuation system. From reviewing the current buckling beam motion amplifier and piezoelectric resonant actuator concepts, it is recognized that an approach that combines the two ideas could further advance the state of the art in achieving high authority, light weight and compact actuators. In this case, resonance means that the operating frequency is at or near the natural frequency of the linearized system, which will cause significant amplification effect of the nonlinear motion amplifier. In this study, a dynamic model is first developed for mechanical tailoring and controller design purposes. A nonlinear feedback linearization control based on the high-gain estimator approach is adopted so that the undesired nonlinear dynamic responses near the resonant frequency, such as the jump phenomena and the chaotic motion, can be avoided.
Parametrization and distillability of three-qubit entanglement

Abstract There is an ongoing effort to quantify entanglement of quantum pure states for systems with more than two subsystems. We consider three approaches to this problem for three-qubit states: choosing a basis which puts the state into a standard form, enumerating “local invariants”, and using operational quantities such as the number of maximally entangled states which can be distilled. In this Letter we evaluate a particular standard form, the Schmidt form, which is a generalization of the Schmidt decomposition for bipartite pure states. We show how the coefficients in this case can be parametrized in terms of five physically meaningful local invariants; we use this form to prove the efficacy of a particular distillation technique for GHZ triplets; and we relate the yield of GHZs to classes of states with unusual entanglement properties, showing that these states represent extremes of distillability as functions of two local invariants.
Light-Duty Diesels—an Update on the Emissions Challenge

The next major stage of emissions legislation for European Community countries is planned for 1996. This paper examines these proposed standards and the effect they will have on light-duty automotive diesel vehicles. The present status of the Clean Air Act amendments in the United States is also considered. The latest developments in light-duty automotive diesel technology are reviewed, particularly with respect to achieving the lower emission standards and the effect on fuel economy.
A complete analytic inversion of supernova lines in the Sobolev approximation

We show that the shape of P-Cygni line profiles of photospheric phase supernova can be analytically inverted to extract both the optical depth and source function of the line -- i.e. all the physical content of the model for the case when the Sobolev approximation is valid. Under various simplifying assumptions, we derive formulae that give S(r) and {tau}(r) in terms of derivatives of the line flux with respect to wavelength. The transition region between the minimum and maximum of the line profile turns out to give especially interesting information on the optical depth near the photosphere. The formulae give insights into the relationship between line shape and physical quantities that may be useful in interpreting observed spectra and detailed numerical calculations.
The Canadian Keiretsu

This article describes the Canadian keiretsu, in which a main Chartered Bank dominates an interlocking group of corporate clients, investment dealers, trust companies, and professional advisors. Such a network facilitates information-sharing and monitoring among group members, while also reducing the agency costs of banker misbehavior. Most major Canadian firms are members of a keiretsu, and stock ownership of Canadian corporations is far more concentrated than ownership of U.S. companies. Given their many similarities of history, law, and geography, Canada and the United States should have ended up with similar corporate ownership and governance structures. But they did not, and the difference was Canada's less restrictive banking and bankruptcy laws, which in turn can be traced to Canada's distinctly non-populist historical experience. The Canadian keiretsu arose primarily for two reasons: (1) the larger concentration of commercial banking (the six largest Canadian banks today account for 98% of the industry's assets) allowed by Canadian law; and (2) the greater powers of Canadian secured lenders in the event of default. Unlike a U.S. Chapter 11 filing, in a Canadian bankruptcy the lender's right to assume control of the assets was not stayed until quite recently. And, even with the recent change in Canadian bankruptcy law, Canadian secured lenders have much stronger protection of their claims in bankruptcy than their U.S. counterparts in Chapter 11.
Atomic moments in Mn2CoAl thin films analyzed by X-ray magnetic circular dichroism

Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The magnetic properties of Mn2CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the atomic-specific magnetic moments of Mn and Co atoms measured through X-ray magnetic circular dichroism as a function of annealing and the consequent structural ordering. The results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value.
A pencil of Enriques surfaces of index one with no section

Monodromy arguments and deformation-and-specialization are used to prove existence of a pencil of Enriques surfaces with no section and index 1. The same technique completes the strategy from [GHMS05, §7.3] proving the family of witness curves for dimension d depends on the integer d.
The Kernel Bundle of a Holomorphic Fredholm Family

Let &#x1d4b4; be a smooth connected manifold, Σ ⊂ ℂ an open set and (σ, y) → &#x1d4ab; y (σ) a family of unbounded Fredholm operators D ⊂ H 1 → H 2 of index 0 depending smoothly on (y, σ) ∈ &#x1d4b4; × Σ and holomorphically on σ. We show how to associate to &#x1d4ab;, under mild hypotheses, a smooth vector bundle &#x1d4a6; → &#x1d4b4; whose fiber over a given y ∈ &#x1d4b4; consists of classes, modulo holomorphic elements, of meromorphic elements φ with &#x1d4ab; y φ holomorphic. As applications we give two examples relevant in the general theory of boundary value problems for elliptic wedge operators.
High-precision gigahertz-to-terahertz spectroscopy of aqueous salt solutions as a probe of the femtosecond-to-picosecond dynamics of liquid water.

Because it is sensitive to fluctuations occurring over femtoseconds to picoseconds, gigahertz-to-terahertz dielectric relaxation spectroscopy can provide a valuable window into water’s most rapid intermolecular motions. In response, we have built a vector network analyzer dielectric spectrometer capable of measuring absorbance and index of refraction in this frequency regime with unprecedented precision. Using this to determine the complex dielectric response of water and aqueous salt solutions from 5.9 GHz to 1.12 THz (which we provide in the supplementary material), we have obtained strong new constraints on theories of water’s collective dynamics. For example, while the salt-dependencies we observe for water’s two slower relaxations (8 and 1 ps) are easily reconciled with suggestions that they arise due to rotations of fully and partially hydrogen bonded molecules, respectively, the salt-dependence of the fastest relaxation (180 fs) appears difficult to reconcile with its prior assignment to liberations of single hydrogen bonds.
Universal correction to the inflationary vacuum

The Bunch-Davies state appears precisely thermal to a free-falling observer in de Sitter space. However, precise thermality is unphysical because it violates energy conservation. Instead, the true spectrum must take a certain different form, with the Boltzmann factor exp (−βωk) replaced by exp (ΔS), where S is the entropy of the de Sitter horizon. The deviation from precise thermality can be regarded as an explicitly calculable correction to the Bunch-Davies state. This correction is mandatory in that it relies only on energy conservation. The modified Bunch-Davies state leads, in turn, to an (H/Mp)2 modification of the primordial power spectrum of inflationary perturbations, which we determine.
Spillovers, stratification, and inequality

This paper surveys some recent work which seeks to model persistent income inequality and explain such phenomena as ghetto formation and poverty traps. The paper illustrates how a number of these models possess a common structure in which local spillover effects interact with income-based stratification of neighborhoods to transmit parental economic status from generation to generation. As such, these models represent an extension of the macroeconomic literature on spillovers and coordination failures to economic environments which endogenize the interaction environments of individual agents. The theoretical and empirical justifications of these spillover and stratification effects are discussed. Finally, some empirical implications of these models are analyzed.
Using Short Movie and Television Clips in the Economics Principles Class

Abstract: The author describes a teaching method that uses powerful contemporary media, movie and television clips, to demonstrate the enormous breadth and depth of economic concepts. Many different movie and television clips can be used to show the power of economic analysis. The author describes the scenes and the economic concepts within those scenes for a number of movies.
The diameter of a long-range percolation graph

We consider the following long-range percolation model: an undirected graph with the node set {0, 1, ..., N}d, has edges (x, y) selected with probability ≈ β/||x -y||s if ||x - y|| ' η1 > η2 > 1, it is at most Nη2 when s = 2d, and is at least Nη1 when d = 1, s = 2, β > 1 or when s > 2d. We also provide a simple proof that the diameter is at most log O(1) N with high probability, when d > s > 2d, established previously in [2].
Differential diffusion in turbulent reacting flows

Results obtained from direct numerical simulations are presented to examine effects due to differential diffusion on reacting scalars in isotropic, decaying turbulence. In the simulations fuel and oxidant react via a one-step, isothermal reaction (activation energy is set to zero). The results demonstrate that effects due to differential diffusion decrease with increasing Reynolds numbers and increase with increasing Damkohler number values. A principal issue investigated in this paper is whether a conditional moment closure-flamelet approach can be applied to accurately account for differential diffusion effects. The results show that the neglect of the conditional fluctuations in the modeling amplifies the influence of differential diffusion and leads to incorrect dependence on the Reynolds number. The paper investigates the different terms representing the conditional fluctuations in the model equations. Also investigated is the influence of differential diffusion on the validity of the boundary conditions set in conserved scalar space.
Magnetic fields and the temperature structure of the chromosphere-corona interface

The temperature structure of the transition region between the chromosphere and corona is discussed in the context of current ideas about magnetic fields in these layers. Magnetic channeling of the downward conductive heat flow from the corona into the regions of enhanced field at the supergranulation boundaries is proposed as a mechanism for explaining the measured intensities of solar ultraviolet emission lines which originate in layers with temperatures below 105 °K. It is shown that nearly all of the observed ultraviolet line emission originates in interspicule regions, and that this emission plays an important part in the energy balance of the cooler layers of the transition region. It is suggested that certain motions observed in the upper chromosphere may represent the earliest visual evidence for conversion of inflowing conduction energy into kinetic motions.
A new approach to the synthesis of the strychnos alkaloids core structure

Abstract The nine-membered ring sec-amine4 reacts with methyl propiolate/sodium hydride in toluene at reflux to give the strychnos core structure12 in a single step.
Wing in heaving oscillatory motion

A wing in steady flight near a wavy surface, such as in the case of a large, transoceanic wingship, is simulated by a wing oscillating in heave near a flat surface. In accord with the wingship, small AR and slight camber are considered. In the present study, consideration is limited to the case when the wavelength of the surface is much greater than the chord of the wing and the slope of the surface is much less than unity. The numerical simulation predicts that the mean aerodynamic loads on a wing executing a simple-harmoni c heaving motion are higher than the corresponding loads on the same wing in steady flight at the mean height and the same angle of attack. These preliminary results suggest that it would be beneficial to fly near the waves and that doing so would improve the aerodynamic efficiency. Also included in the present results are numerical simulations of the wakes that show the strong influences of the ground and the oscillations on their behavior.
Event-by-event Modeling of Prompt Neutrons and Photons from Neutron-induced and Spontaneous Fission with FREYA

Abstract The fast event-by-event fission code FREYA generates large samples of complete fission events. Using FREYA , it is possible to obtain the fission products as well as the prompt neutrons and photons emitted during the fission process, all with complete kinematic information. We can therefore extract any desired correlation observables. Concentrating on 239 Pu(n,f), 235 U(n,f) and 252 Cf(sf), we compare our FREYA results with available data on prompt neutron and photon emission.
Self-Consistent Models of the Solar Wind

The origins of the hot solar corona and the supersonically expanding solar wind are still the subject of much debate. This paper summarizes some of the essential ingredients of realistic and self-consistent models of solar wind acceleration. It also outlines the major issues in the recent debate over what physical processes dominate the mass, momentum, and energy balance in the accelerating wind. A key obstacle in the way of producing realistic simulations of the Sun-heliosphere system is the lack of a physically motivated way of specifying the coronal heating rate. Recent models that assume the energy comes from Alfven waves that are partially reflected, and then dissipated by magnetohydrodynamic turbulence, have been found to reproduce many of the observed features of the solar wind. This paper discusses results from these models, including detailed comparisons with measured plasma properties as a function of solar wind speed. Some suggestions are also given for future work that could answer the many remaining questions about coronal heating and solar wind acceleration.
Interprocedural slicing using dependence graphs

The notion of a program slice, originally introduced by Mark Weiser, is useful in program debugging, automatic parallelization, and program integration. A slice of a program is taken with respect to a program point p and a variable x; the slice consists of all statements of the program that might affect the value of x at point p. This paper concerns the problem of interprocedural slicing—generating a slice of an entire program, where the slice crosses the boundaries of procedure calls. To solve this problem, we introduce a new kind of graph to represent programs, called a system dependence graph, which extends previous dependence representations to incorporate collections of procedures (with procedure calls) rather than just monolithic programs. Our main result is an algorithm for interprocedural slicing that uses the new representation. (It should be noted that our work concerns a somewhat restricted kind of slice: rather than permitting a program to b e sliced with respect to program point p and an arbitrary variable, a slice must be taken with respect to a variable that is defined or used at p.)The chief difficulty in interprocedural slicing is correctly accounting for the calling context of a called procedure. To handle this problem, system dependence graphs include some data dependence edges that represent transitive dependences due to the effects of procedure calls, in addition to the conventional direct-dependence edges. These edges are constructed with the aid of an auxiliary structure that represents calling and parameter-linkage relationships. This structure takes the form of an attribute grammar. The step of computing the required transitive-dependence edges is reduced to the construction of the subordinate characteristic graphs for the grammar's nonterminals.
Local cohomology properties of direct summands

Abstract In this article, we prove that if R → S is a homomorphism of Noetherian rings that splits, then for every i ≥ 0 and ideal I ⊂ R , Ass R H I i ( R ) is finite when Ass S H I S i ( S ) is finite. In addition, if S is a Cohen–Macaulay ring that is finitely generated as an R -module, such that all the Bass numbers of H I S i ( S ) , as an S -module, are finite, then all the Bass numbers of H I i ( R ) , as an R -module, are finite. Moreover, we show these results for a larger class a functors introduced by Lyubeznik [5] . As a consequence, we exhibit a Gorenstein F -regular UFD of positive characteristic that is not a direct summand, not even a pure subring, of any regular ring.
Orbit Radial Dynamic Analysis of Two-Craft Coulomb Formation at Libration Points

The linearized orbit radial dynamics and stability analysis of a two-craft virtual Coulomb structure at Earth–moon libration points are investigated. The linearized study assumes that the sunlit areas of the two-craft structure are equal such that the differential solar radiation pressure on the formation is zero. The relative distance between the two satellites of the Coulomb tether is controlled using electrostatic Coulomb forces. The separation distance between the satellites is stabilized with a charge feedback law that maintains the relative distance at a constant value. The electrostatic virtual tether between the two craft is capable of both tensile and compressive forces. The gravity gradient torques on the formation due to the two celestial objects is exploited to stabilize the Coulomb tether formation in the orbit radial direction. Controlling the separation distance stabilizes the in-plane rotation angle; however, the out-of-plane rotational motion is not affected by the spacecraft charge contr...
Evanescent-wave bonding between optical waveguides

Forces arising from overlap between the guided waves of parallel, microphotonic waveguides are calculated. Both attractive and repulsive forces, determined by the choice of relative input phase, are found. Using realistic parameters for a silicon-on-insulator material system, we estimate that the forces are large enough to cause observable displacements. Our results illustrate the potential for a broader class of optically tunable microphotonic devices and microstructured artificial materials.
Effects of Welfare Participation on Marriage

We investigate the widely held premise that welfare participation causes women to refrain from marriage. Using data from the Fragile Families and Child Wellbeing study (N = 3,219), we employ an event history approach to study transitions to marriage among mothers who have had a non-marital birth. We find that welfare participation reduces the likelihood of transitioning to marriage (hazard ratio is .67, p < .01), but only while the mother is receiving benefits. Once the mother leaves welfare, past receipt has little effect on marriage. We infer that the negative association between welfare participation and subsequent marriage reflects temporary economic disincentives rather than an erosion of values.
Conformation-Family Monte Carlo (CFMC): An Efficient Computational Method for Identifying the Low-Energy States of a Macromolecule

A highly efficient method, Conformation-Family Monte Carlo (CFMC), has been developed for searching the conformational space of a macromolecule and identifying its low-energy conformations. This method maintains a database of low-energy conformations that are clustered into families. The conformations in this database are improved iteratively by a Metropolis-type Monte Carlo procedure, together with energy minimization, in which the search is biased towards investigating the regions of the lowest-energy families. The CFMC method has the advantages of our earlier potential-smoothing methods (in that it `coarse-grains' the conformational space and exploits information about nearby low-energy states), but avoids their disadvantages (such as the displacement of the global minimum at large smoothings). The CFMC method is applied to a test protein, domain B of Staphylococcal protein A. Independent CFMC runs yielded the same low-energy families of conformations from random starts, indicating that the thermodynamically relevant conformational space of this protein has been explored thoroughly. The CFMC method is highly efficient, performing as well as or better than competing methods, such as Monte Carlo with minimization, conformational-space annealing, and the self-consistent basin-to-deformed-basin method.
Effective hamiltonians for 1/N expansion in two-dimensional QCD

Abstract We discuss the general structure of effective hamiltonians for systematic 1/N expansion in QCD using the light-cone quantization. These are second-quantized hamiltonians acting on the Fock space of mesons and glueballs defined by the solution of the N = ∞ problem. In the two-dimensional case we find only cubic and quartic interaction terms, and give explicit expressions for the vertex functions as integrals of solutions of 't Hooft equation. As examples of possible applications of our formalism, we study 1/N corrections to meson mass and form factors for decays of Q q states, recently discussed by Grinstein and Mende in the large-N limit. We find that 1/N is a good small expansion parameter.
Mechanism of steel corrosion in concentrated NaOH solutions

Abstract A study has been made of the mechanism of corrosion of carbon steel in 1–19 N NaOH at 25–80°C. The polarization curves were obtained with a rotating steel disk electrode, and the rotating ring-hemisphere electrode technique was used to identify soluble corrosion products. It was found that at the active anodic dissolution potentials, steel dissolves to form HFeO − 2 ions. Both the anodic and cathodic polarization curves exhibited a well defined Tafel regime, and the electrokinetic parameters were obtained for the corrosion of steel. The results were interpreted with a corrosion mechanism based on the decomposition of molecular water to hydrogen at the cathodic sites, and the active dissolution of iron to HFeO − 2 ions via two adsorbed intermediates, FeOH ads and Fe(OH) 2,ads , at the anodic sites. The theoretically derived anodic Tafel slope, anodic reaction order, corrosion potential, and corrosion current density agreed quantitatively with the experimental values. At the potentials above the anodic Tafel regime and in the neighborhood of the active—passive transition potential, steel dissolved to form both the bi-valent and tri-valent iron species, HFeO − 2 and FeO − 2 ions. The thermodynamic considerations revealed that FeO − 2 ion was formed from the oxidation of Fe(OH) 2,ads intermediate, rather than from the oxidation of HFeO − 2 ion on steel surface.
Polarimetry in the visible and infrared: application to CMB polarimetry

Abstract Interstellar polarization from aligned dust grains can be measured both in transmission at visible and near-infrared wavelengths and in emission at far-infrared and sub-mm wavelengths. These observations can help predict the behavior of foreground contamination of CMB polarimetry by dust in the Milky Way. Fractional polarization in emission from aligned dust grains will be at the higher range of currently observed values of 4–10%. Away from the galactic plane, fluctuations in Q and U will be dominated by fluctuations in intensity, and less influenced by fluctuations in fractional polarization and position angle.
Stopping, storing and releasing light in quantum well Bragg structures

Stopping, storing and releasing of light in resonant photonic bandgap structures made from Bragg-spaced quantum wells is studied. The expected performance of almost ideal infinite systems is contrasted with that of existing structures.
Maximal Sensitive Dependence and the Optimal Path to Epidemic Extinction

Extinction of an epidemic or a species is a rare event that occurs due to a large, rare stochastic fluctuation. Although the extinction process is dynamically unstable, it follows an optimal path that maximizes the probability of extinction. We show that the optimal path is also directly related to the finite-time Lyapunov exponents of the underlying dynamical system in that the optimal path displays maximum sensitivity to initial conditions. We consider several stochastic epidemic models, and examine the extinction process in a dynamical systems framework. Using the dynamics of the finite-time Lyapunov exponents as a constructive tool, we demonstrate that the dynamical systems viewpoint of extinction evolves naturally toward the optimal path.
Multilevel coding schemes for compute-and-forward

We consider the design of coding schemes for the wireless two-way relaying channel when there is no channel state information at the transmitter. In the spirit of the compute and forward paradigm, we present a multilevel coding scheme that permits the recovery of a class of functions at the relay. We define such a class of functions and derive rates that are universally achievable over a set of channel gains when this class of functions is used at the relay. We develop our framework with general modulation formats in mind, but numerical results are presented for the case where each node transmits using the QPSK constellation. Numerical results with QPSK show that substantially higher rates are achievable with our proposed approach than those achievable by always using a fixed function or adapting the function at the relay but coding over GF(4).
Accounting for Wage and Employment Changes in the U.S. from 1968-2000: A Dynamic Model of Labor Market Equilibrium

In this article, we present a unified treatment of and explanation for the evolution of wages and employment in the US over the last 30 years. Specifically, we account for the pattern of changes in wage inequality, for the increased relative wage and employment of women, for the emergence of the college wage premium and for the shift in employment from the goods to the service-producing sector. The underlying theory we adopt is neoclassical, a two-sector competitive labor market economy in which the supply of and demand for labor of heterogeneous skill determines spot market skill rental prices. The empirical approach is structural. The model embeds many of the features that have been posited in the literature to have contributed to the changing US wage and employment structure including skill-biased technical change, capital-skill complementarity, changes in relative product-market prices, changes in the productivity of labor in home production and demographics such as changing cohort size and fertility.
Minimum Complexity Pursuit for Universal Compressed Sensing

The nascent field of compressed sensing is founded on the fact that high-dimensional signals with simple structure can be recovered accurately from just a small number of randomized samples. Several specific kinds of structures have been explored in the literature, from sparsity and group sparsity to low-rankness. However, two fundamental questions have been left unanswered. What are the general abstract meanings of structure and simplicity? Do there exist universal algorithms for recovering such simple structured objects from fewer samples than their ambient dimension? In this paper, we address these two questions. Using algorithmic information theory tools such as the Kolmogorov complexity, we provide a unified definition of structure and simplicity. Leveraging this new definition, we develop and analyze an abstract algorithm for signal recovery motivated by Occam's Razor. Minimum complexity pursuit (MCP) requires approximately 2κ randomized samples to recover a signal of complexity κ and ambient dimension n. We also discuss the performance of the MCP in the presence of measurement noise and with approximately simple signals.
The expanding role of Wnt signaling in bone metabolism

The quest for targetable molecules and pathways that can be manipulated to treat skeletal disease and restore bone health is perpetually evolving. Successful pharmacologic treatment of nearly all skeletal diseases among adults, and many pediatric skeletal diseases, requires a fundamental understanding of the influence that different signaling pathways exert on the bone remodeling cycle. Because pharmacologic agents that improve bone mass and fracture susceptibility can work by increasing [1] or by decreasing [2] bone turnover, it is clear that the effects of any agent on both resorptive and formation arms of the remodeling cycle are key to its success. Recently, a great deal of therapeutic interest has developed around the Wnt signaling pathway in light of the high bone mass phenotype observed among patients with certain mutations in Wnt-signaling-associated genes.
A Rigorous Analysis Using Optimal Transport Theory for a Two-reflector Design Problem with a Point Source

We consider the following geometric optics problem: construct a system of two reflectors which transforms a spherical wavefront generated by a point source into a beam of parallel rays. This beam has a prescribed intensity distribution. We give a rigorous analysis of this problem. The reflectors we construct are (parts of) the boundaries of convex sets. We prove existence of solutions for a large class of input data and give a uniqueness result. To the author's knowledge, this is the first time that a rigorous mathematical analysis of this problem is given. The approach is based on optimal transportation theory. It yields a practical algorithm for finding the reflectors. Namely, the problem is equivalent to a constrained linear optimization problem.
Constructing design plans for DFA redesign

Design-for-assembly (DFA) analysis of a product may indicate shortcomings of a design, without providing specific guidance on redesigns. A computational tool for assisting redesigns of mechanical assemblies for DFA is introduced. The system, named REV-ENGE, is based on a model of reverse engineering in order to incorporate design rationale into the redesign process. The system consists of three major parts: knowledge acquisition, construction of a default design plan, and case-based redesign. The authors emphasize how a design plan, which serves as the basis for constructing a redesign plan, can be generated with user assistance. A simple example of a redesign of a container is illustrated. REV-ENGE produces redesign plans by constructing and modifying the original design plan, and facilitates the redesign process by providing a specific order and design actions to carry out, while considering design rationale. >
Advantages of Randomization in Coherent Quantum Dynamical Control

Control scenarios have been identified where the use of randomized design may substantially improve the performance of dynamical decoupling methods (Santos and Viola 2006 Phys. Rev. Lett. 97 150501). Here, by focusing on the suppression of internal unwanted interactions in closed quantum systems, we review and further elaborate on the advantages of randomization at long evolution times. By way of illustration, special emphasis is devoted to isolated Heisenberg chains of coupled spin-1/2 particles. In particular, for nearest-neighbor interactions, two types of decoupling cycles are contrasted: inefficient averaging, whereby the number of control actions increases exponentially with the system size, and efficient averaging associated to a fixed-size control group. The latter allows for analytical and numerical studies of efficient decoupling schemes created by exploiting and merging together randomization and deterministic strategies, such as symmetrization, concatenation and cyclic permutations. Notably, sequences capable of removing interactions up to third order in the achievable control timescale are explicitly constructed, and a numerical algorithm to search for optimal decoupling sequences is proposed. The consequences of faulty controls in deterministic versus randomized schemes are also analyzed.
Effects of tripropellant engines on earth-to-orbit vehicles

The effects of tripropellant engines on earth-to-orbit vehicles is examined in terms of their impact on engine configurations and launch capabilities. Hydrocarbon fuel with some oxygen is used in tripropellant fuels, with hydrogen as a back-up fluid for coolant and driving the pumps. Engine concepts which implement tripropellant fuels include a hydrogen-gas generator engine with staged combustion, a two-mode engine burning hydrocarbon fuel in one chamber and hydrogen in another, a dual expander engine with a central hydrocarbon nozzle and an annular hydrogen nozzle, and a dual throat engine. The use of hydrocarbons reduces the fuel weight by providing a higher specific impulse than with LOX-LH2 systems alone. Studies have shown that single-stage-to-orbit vehicles capable of lifting 13.6 Mg are possible with tripropellant engines. A dual-expander engine, is identified as offering the most fuel dry mass reduction for a given payload if cooling requirements can be satisfied. Further development of the tripropellant engines is concluded to be beneficial.
A Quantum Logic Array Microarchitecture: Scalable Quantum Data Movement and Computation

Recent experimental advances have demonstrated technologies capable of supporting scalable quantum computation. A critical next step is how to put those technologies together into a scalable, fault-tolerant system that is also feasible. We propose a quantum logic array (QLA) microarchitecture that forms the foundation of such a system. The QLA focuses on the communication resources necessary to efficiently support fault-tolerant computations. We leverage the extensive groundwork in quantum error correction theory and provide analysis that shows that our system is both asymptotically and empirically fault tolerant. Specifically, we use the QLA to implement a hierarchical, array-based design and a logarithmic expense quantum-teleportation communication protocol. Our goal is to overcome the primary scalability challenges of reliability, communication, and quantum resource distribution that plague current proposals for large-scale quantum computing. Our work complements recent work by Balenseifer et al. (2005), which studies the software tool chain necessary to simplify development of quantum applications; here we focus on modeling a full-scale optimized microarchitecture for scalable computing.
Disk aware discord discovery: finding unusual time series in terabyte sized datasets

The problem of finding unusual time series has recently attracted much attention, and several promising methods are now in the literature. However, virtually all proposed methods assume that the data reside in main memory. For many real-world problems this is not be the case. For example, in astronomy, multi-terabyte time series datasets are the norm. Most current algorithms faced with data which cannot fit in main memory resort to multiple scans of the disk /tape and are thus intractable. In this work we show how one particular definition of unusual time series, the time series discord, can be discovered with a disk aware algorithm. The proposed algorithm is exact and requires only two linear scans of the disk with a tiny buffer of main memory. Furthermore, it is very simple to implement. We use the algorithm to provide further evidence of the effectiveness of the discord definition in areas as diverse as astronomy, web query mining, video surveillance, etc., and show the efficiency of our method on datasets which are many orders of magnitude larger than anything else attempted in the literature.
A bilinear estimate for biharmonic functions in Lipschitz domains

We show that a bilinear estimate for biharmonic functions in a Lipschitz domain Ω is equivalent to the solvability of the Dirichlet problem for the biharmonic equation in Ω. As a result, we prove that for any given bounded Lipschitz domain Ω in $${\mathbb{R}^{d}}$$ and 1 < q < ∞, the solvability of the L q Dirichlet problem for Δ 2 u = 0 in Ω with boundary data in WA 1,q (∂Ω) is equivalent to that of the L p regularity problem for Δ 2 u = 0 in Ω with boundary data in WA 2,p (∂Ω), where $${\frac{1}{p} + \frac{1}{q}=1}$$ . This duality relation, together with known results on the Dirichlet problem, allows us to solve the L p regularity problem for d ≥ 4 and p in certain ranges.
Adaptive estimation of cointegrating regressions with ARMA errors

Adaptive maximum likelihood estimators are derived for the parameters of a cointegrating regression whose errors follow a stationary and invertible ARMA process with innovations of unknown distribution. It is shown how to use preliminary estimates of these innovations to nonparametrically estimate their density, which can in turn be used to construct an asymptotically efficient iterative estimator of the cointegrating vector. The asymptotic distribution of this estimator is derived, as are its efficiency gains relative to the Gaussian pseudo-MLE. We evaluate the finite sample behaviour of the estimator through a small Monte Carlo experiment, and report the results of an empirical application to the foreign exchange market.