cssi/SciSciGPT-SciSciNet huggingface dataset:
Differential operators and BV structures in noncommutative geometry

We introduce a new formalism of differential operators for a general associative algebra A. It replaces Grothendieck’s notion of differential operators on a commutative algebra in such a way that derivations of the commutative algebra are replaced by $${\mathbb{D}{\rm er}(A)}$$ , the bimodule of double derivations. Our differential operators act not on the algebra A itself but rather on $${\mathcal{F}(A)}$$ , a certain ‘Fock space’ associated to any noncommutative algebra A in a functorial way. The corresponding algebra $${\mathcal{D}(\mathcal{F}(A))}$$ of differential operators is filtered and gr $${\mathcal{D}(\mathcal{F}(A))}$$ , the associated graded algebra, is commutative in some ‘wheeled’ sense. The resulting ‘wheeled’ Poisson structure on gr $${\mathcal{D}(\mathcal{F}(A))}$$ is closely related to the double Poisson structure on $${T_{A} \mathbb{D}{\rm er}(A)}$$ introduced by Van den Bergh. Specifically, we prove that gr $${\mathcal{D}(\mathcal{F}(A))\cong\mathcal{F}(T_{A}(\mathbb{D}{\rm er}(A)),}$$ provided the algebra A is smooth. Our construction is based on replacing vector spaces by the new symmetric monoidal category of wheelspaces. The Fock space $${\mathcal{F}(A)}$$ is a commutative algebra in this category (a “commutative wheelgebra”) which is a structure closely related to the notion of wheeled PROP. Similarly, we have Lie, Poisson, etc., wheelgebras. In this language, $${\mathcal{D}(\mathcal{F}(A))}$$ becomes the universal enveloping wheelgebra of a Lie wheelgebroid of double derivations. In the second part of the paper, we show, extending a classical construction of Koszul to the noncommutative setting, that any Ricci-flat, torsion-free bimodule connection on $${\mathbb{D}{\rm er}(A)}$$ gives rise to a second-order (wheeled) differential operator, a noncommutative analogue of the Batalin-Vilkovisky (BV) operator, that makes $${\mathcal{F}(T_{A}(\mathbb{D}{\rm er}(A)))}$$ a BV wheelgebra. In the final section, we explain how the wheeled differential operators $${\mathcal{D}(\mathcal{F}(A))}$$ produce ordinary differential operators on the varieties of n-dimensional representations of A for all n ≥ 1.
On a common generalization of Koszul duality and tilting equivalence

Abstract We propose a new definition of Koszulity for graded algebras where the degree zero part has finite global dimension, but is not necessarily semi-simple. The standard Koszul duality theorems hold in this setting.
The CKM Matrix from Lattice QCD

Lattice QCD plays an essential role in testing and determining the parameters of the CKM theory of flavor mixing and CP violation. Very high precisions are required for lattice calculations analyzing CKM data; I discuss the prospects for achieving them. Lattice calculations will also play a role in investigating flavor mixing and CP violation beyond the Standard Model.
Following a “Balanced” Trajectory from an Infeasible Point to an Optimal Linear Programming Solution with a Polynomial-Time Algorithm

This paper is concerned with the problem of following a trajectory from an infeasible starting point directly to an optimal solution of the linear programming problem. A class of trajectories for the problem is defined, based on the notion of a β-balanced solution to the problem. Given a prespecified positive balancing constant β, an infeasible solution x is said to be β-balanced if the optimal value gap is less than or equal to β times the infeasibility gap. Mathematically, this can be written as cTx-z* ≤ βξTx, where the linear form ξTx is the Phase I objective function and z* is the optimal objective value of the linear program. The concept of a β-balanced solution is used to define a class of trajectories from an infeasible point to an optimal solution of a given linear program. Each trajectory has the property that all points on or near the trajectory in a suitable metric are β-balanced. The main thrust of the paper is the development of an algorithm that traces a given β-balanced trajectory from a starting point near the trajectory to an optimal solution to the given linear programming problem in polynomial time. More specifically, the algorithm allows for fixed improvement in the bound on the Phase I and the Phase II objectives in On Newton steps.
Nitrous acid induced damage in T7 DNA and phage.

T7 phage was exposed to 56 mM nitrous acid at pH 4.6 causing a 90% decrease in survival for each 10 min duration of exposure. The survival of phage made by encapsulating nitrous acid treated DNA into empty phage heads was nearly the same as the survival of phage exposed to nitrous acid in vivo. In contrast to previous reports, growth of SOS-induced wild-type E.coli showed no increase in survival. The survival of nitrous acid treated phage was not lowered when grown on E.coli strains deficient in DNA polymerase I, exonuclease III, and the uvrA component of the nucleotide excision-repair endonuclease. Therefore, these enzymes are not vital for repair of nitrous acid induced damage in bacteriophage T7.
RF accelerators for fusion and strategic defense

In summary, we have found that rf linacs do have a place in fusion, either in an auxiliary role for materials testing or for direct drivers in heavy-ion fusion. For SDI, the particle-beam technology is an attractive candidate for discrimination missions and also for lethality missions. The free-electron laser is also a forerunner among the laser candidates.
Financial Market Imperfections and Business Cycles

Because of financial market imperfections, such as those generated by asymmetric information in financial markets, which lead to breakdowns in markets, like that for equity, in which risks are shared, firms act in a risk-averse manner. The resulting macroeconomic model accounts for many widely observed aspects of actual business cycles: (a) cyclical movements in real product wages, (b) cyclical patterns of output and investment including inventories, (c) sensitivity of the economy to small perturbations, and (d) persistence. More downward flexibility in wages and prices may exacerbate the plight of an economy that is in a deep recession.
The noisy voter-exclusion process

The symmetric exclusion process and the voter model are two interacting particle systems for which a dual finite particle system allows one to characterize its invariant measures. Adding spontaneous births and deaths to the two processes still allows one to use the dual process to obtain information concerning the original process. This paper introduces the noisy voter-exclusion process which generalizes these processes by allowing for all of these interactions to take place. The dual process is used to characterize its invariant measures under various circumstances. Finally, an ergodic theorem for a related process is proved using the coupling method.
Synthesis of some benzimidazole‐, pyridine‐ and imidazole‐derived chelating agents

Procedures are described for the preparation of various bidentate and potentially tridentate chelating agents. These incorporate pyridyl, benzimidazole, imidazole or phenolic moieties. Phillips condensations of carboxylic acids with o-phenylenediamines were carried out in 4 M hydrochloric acid. Syntheses are reported for 2, 6-bis(N′-methylimidazol-2′-ylthiomethyl)pyridine, 2, 6-bis(benzimidazol-2′-ylthiomethyl)pyridine, 2-(4′-piperidyl)benzimidazole, 2-(3′-piperidyl)benzimidazole, 2-(3-N′-methylpiperidyl)benziinidazole, 2-(3-N′-methylpiperidyl)-N-methylbenzimidazole, 2-(2′-hydroxybenzyl)benzimidazole and 2-(2′-hydroxyben-zyl)N-methylbenzimidazole. The compounds were characterized where appropriate by their mass, uv, and 1H-nmr spectra. 2-(2′-Hydroxybenzyl)benzimidazole hydrochloride acts as a gelling agent in aqueous solution.
Commitment and self-control

Abstract The literature on self-control problems has typically concentrated on immediate temptations. This paper studies a Gul and Pesendorfer [Temptation and self-control, Econometrica 69 (2001) 1403–1435; Self-control and the theory of consumption, Econometrica 72 (2004) 119–158] style model in which decision-makers are affected by temptations that lie in the future. While temptation is commonly understood to give rise to a demand for commitment, it is shown that ‘temptation by future consumption’ can induce its absence. The model also exhibits procrastination, provides an alternative to projection bias as an explanation for some experimental results, and can simultaneously account for myopic and hyperopic behavior. The evidence on preference reversals supports temptation by future consumption, and suggests that it may not be restricted to short time horizons.
Protein Thioester Synthesis Enabled by Sortase

Proteins containing a C-terminal thioester are important intermediates in semisynthesis. Currently there is one main method for the synthesis of protein thioesters that relies upon the use of engineered inteins. Here we report a simple strategy, utilizing sortase A, for routine preparation of recombinant proteins containing a C-terminal (α)thioester. We used our method to prepare two different anthrax toxin cargo proteins: one containing an (α)thioester and another containing a D-polypeptide segment situated between two protein domains. We show that both variants can translocate through protective antigen pore. This new method to synthesize a protein thioester allows for interfacing of sortase-mediated ligation and native chemical ligation.
Quantum Computing and Quantum Measurement with Mesoscopic Josephson Junctions

Recent experimental demonstrations of quantum coherence of the charge and flux states of Josephson junctions show that the quantum Josephson dynamics can be used to develop scalable quantum logic circuits. In this work, I review the basic concepts of Josephson tunneling and Josephson-junction qubits, and discuss two problems of this tunneling motivated by quantum computing applications. One is the theory of photon-assisted resonant flux tunneling in SQUID systems used to demonstrate quantum coherence of flux. Another is the problem of quantum measurement of charge with the SET electrometer. It is shown that the SET electrometer at the Coulomb blockade threshold is the quantum-limited detector with energy sensitivity reaching ħ/√3 in the resonant-tunneling regime.
Engineering Gesture-Based Authentication Systems

Gestures are a topic of increasing interest in authentication, but successfully implementing them as a security layer requires reliable gesture recognition. So far, much work focuses on new ways to recognize gestures, leaving discussion on the viability of recognition in an authentication scheme to the background. It's as yet unclear how gesture recognition should be deployed for practical and robust real-world authentication. In this article, the authors analyze the effectiveness of different approaches to recognizing gestures and the potential for use in secure gesture-based authentication systems. This article is part of a special issue on privacy and security.
Analysis of a proposed Compton backscatter imaging technique

One-sided imaging techniques are currently being used in nondestructive evaluation of surfaces and shallow subsurface structures. In this work we present both analytical calculations and detailed Monte Carlo simulations aimed at assessing the capability of a proposed Compton backscattering imaging technique designed to detect and characterize voids located several centimeters below the surface of a solid.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
The existence of soliton metrics for nilpotent Lie groups

We show that a left-invariant metric g on a nilpotent Lie group N is a soliton metric if and only if a matrix U and vector v associated the manifold (N, g) satisfy the matrix equation Uv = [1], where [1] is a vector with every entry a one. We associate a generalized Cartan matrix to the matrix U and use the theory of Kac–Moody algebras to analyze the solution spaces for such linear systems. An application to the existence of soliton metrics on certain filiform Lie groups is given.
THE DISTRIBUTION OF THE LOGARITHMIC DERIVATIVE OF THE RIEMANN ZETA-FUNCTION

We investigate the distribution of the logarithmic derivative of the Riemann zeta-function on the line Re(s)=\sigma, where \sigma, lies in a certain range near the critical line \sigma=1/2. For such \sigma, we show that the distribution of \zeta'/\zeta(s) converges to a two-dimensional Gaussian distribution in the complex plane. Upper bounds on the rate of convergence to the Gaussian distribution are also obtained.
Time-resolved surface heat flux measurements in the wing/body junction vortex

Time- and spatially-resolved heat flux measurements are reported for the endwall surface in the turbulent, incompressible flow in the nose region of a wing-body junction formed by a wing and a flat plate. Both the wing and the flat plate were heated and held at a constant and uniform temperature. The effects of cylindrical wing geometry on heat flux were investigated by taking heat flux measurements in the nose regions of a 3:2 elliptic nose/NACA 0020 tail shape, a circular cylinder with a wedge tail, and an NACA 0015. Heat flux rates were increased up to a factor of 3 over the heat flux rates in the approach boundary layer. The rms of the heat flux fluctuations were as high as 25% of the mean heat flux in the vortex-dominated nose region. Away from the wing, upstream of the time-averaged vortex center, augmentation in the heat flux is due to increased turbulent mixing caused by large-scale unsteadiness of the vortex. A new three-dimensional extension of an existing correlation is proposed to account for the effects of the horseshoe vortex on heat transfer in this region. Adjacent to the wing the augmentation in heat flux is due to a change in the mean velocity field.
Spectrum of weighted composition operators. Part II: weighted composition operators on subspaces of Banach lattices

We describe the spectrum of weighted \(d\)-isomorphisms of Banach lattices restricted on closed subspaces that are “rich” enough to preserve some “memory” of the order structure of the original lattice. The examples include (but are not limited to) weighted isometries of Hardy spaces on the polydisk and unit ball in \(\mathbb C ^n\).
The reaction of XeF2 with trialkylvinylstannanes: Scope and some mechanistic observations

Abstract The combination of a vinylstannane with xenon difluoride in the presence of silver(I) triflate results in a very rapid process leading to the corresponding vinyl fluoride. The reaction is regio- and stereospecific and does not require stoichiometric Ag(I). No evidence could be obtained of radical intermediates on the reaction pathway leading to the vinyl fluorides. A symmetrical dimer derived from the vinylstannane, which was obtained as a reaction byproduct, was shown to arise from oxidative coupling by the silver salt. The results are consistent with an electrophilic mechanism following an initial interaction of the vinylstannane with Ag(I).
Gravitational Lensing by Burkert Halos

We investigate the gravitational lensing properties of dark matter halos with Burkert profiles. We derive an analytic expression for the lens equation and use it to compute the magnification, impact parameter, and image separations for strong lensing. For the scaling relation that provides the best fits to spiral galaxy rotation curve data, Burkert halos will not produce strong lensing, even if this scaling relation extends up to masses of galaxy clusters. Tests of a simple model of an exponential stellar disk superposed on a Burkert profile halo demonstrate that strong lensing is unlikely without an additional concentration of mass in the galaxy center (e.g., a bulge). The fact that most strong lenses on galactic scales are elliptical galaxies suggests that a strong central concentration of baryons is required to produce image splitting. This solution is less attractive for clusters of galaxies, which are generally considered to be dark matter dominated even at small radii. There are three possible implications of these results: (1) dark halos may have a variety of inner profiles, (2) dark matter halos may not follow a single scaling relation from galaxy scale up to cluster scale, and/or (3) the splitting of images (even by clusters of galaxies) may in general be due to the central concentration of baryonic material in halos rather than dark matter.
Stop and Go Agricultural Policies with a Land Market

This article studies the design of farm policy in the presence of asymmetric information about farmers' productivity, a government objective to insure farmers a minimum “parity” income, an endogenous land rent, and diminishing returns on alternative (nonprogram crop) land uses. In this setting, acreage set asides are never part of an optimal farm policy, although compensated acreage limits are. When there are new farmer entrants who cannot be excluded from farm programs, optimal policy takes the form of a pure voluntary acreage limitation—or “buyout”—program in which high-cost producers participate and low-cost producers do not. Copyright 2003, Oxford University Press.
Improved and Highly Versatile Synthesis of 5‐Aryltropones

Abstract The use of 5‐iodo‐2‐methoxytropone in palladium(0)‐catalyzed coupling reactions with a variety of arylboronic acids has resulted in significantly improved reaction yields and times for a sterically and electronically diverse series of novel 5‐aryltropones. In addition, the required 5‐iodo‐2‐methoxytropone was conveniently synthesized in excellent yield.
Knot Floer homology and integer surgeries

Let Y be a closed three-manifold with trivial first homology, and let K Y be a knot. We give a description of the Heegaard Floer homology of integer surgeries on Y along K in terms of the filtered homotopy type of the knot invariant for K . As an illustration of these techniques, we calculate the Heegaard Floer homology groups of non-trivial circle bundles over Riemann surfaces (with coefficients in Z=2Z). 57M27; 57M25
Dynamic unstructured method for flows past multiple objects in relative motion

A new methodology is developed to simulate unsteady flows about objects in relative motion and compute the trajectory of their motion as determined by this flowfield. The method couples the fluid dynamics and rigid-body dynamics equations to capture the time-dependent interference between stationary and moving boundaries. The unsteady, compressible, inviscid (Euler) equations are solved on dynamic unstructured grids by an explicit, finite-volume, upwind method. For efficiency, the grid adaptation is perfomed within a window around the moving object. The Eulerian equations of the rigid-body dynamics are solved by a Runge-Kutta method in a noninertial frame of reference. This dynamic, unstructured flow solver is validated by computing the flow past a sinusoidally pitching airfoil and comparing these results with the experimental data. The trajectory code is tested by computing the six-degree-of-freedom trajectory of a store separating from a wing using the experimentally determined force and moment fields, then comparing with the experimental trajectory. Finally, the overall methodology is used for two two-dimensional examples: the flow past a pitching and plunging airfoil, and the free call of a store after separation from a wing section
Bargaining dynamics in exchange networks

Abstract We consider a one-sided assignment market or exchange network with transferable utility and the dynamics of bargaining in such a market. Our dynamical model is local, involving iterative updates of ‘offers’ based on estimated best alternative matches, in the spirit of pairwise Nash bargaining. Agents are not strategic in our model. We establish that when a balanced outcome (a generalization of the pairwise Nash bargaining solution to networks) exists, our dynamics converges rapidly to such an outcome.
Aerodynamic parameter identification for symmetric projectiles: An improved gradient based method

Abstract In order to estimate the aerodynamic coefficients of a symmetric projectile from free flight range data, an algorithm using traditional linear theory with non-linear programming is investigated. The linear theory solution is reformulated resulting in matrix expressions of improved compactness and simplicity, which provide predictions of yaw, pitch, crossrange, and altitude as functions of downrange travel. The new solution is easily differentiated with respect to aerodynamic coefficients such that a gradient based output error estimation algorithm naturally follows. Numerical results are presented and compared to a previous method that required finite differencing for gradient estimates.
Política exterior chilena en la disyuntiva regional: el conflicto territorial ecuatoriano-peruano hacia 1910

El estudio de las relaciones interestatales en America Latina a fines del siglo XIX y principios del XX es un aliciente para comprender los procesos de consolidacion de espacios territoriales. Las disputas territoriales de caracter bilateral dieron paso a la intervencion de terceros Estados, ya sea por los propios intereses nacionales o por un deseo de conseguir acuerdos, evitando asi una guerra. Es por ello que el objetivo de este trabajo es presentar la posicion de la politica exterior chilena frente al escenario conflictivo ecuatoriano-peruano hacia 1910, ya que Chile mantenia intereses en Ecuador y problemas pendientes con Peru. No obstante, logro mantener un discurso hacia la paz regional y la negociacion.
Do Pleiotropic Effects of Antihypertensive Medications Exist or Is It All About the Blood Pressure

Examination of the large-scale drug-versus-drug trials suggests that the initial drug choice is of token importance and that better blood pressure control is the primary determinant of superior outcomes. In pooled analyses, the achieved blood pressure is similar for older and less expensive drugs, such as thiazide-type diuretics, and for newer and more costly agents, such as angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, and calcium-channel blockers. If blood pressure-independent differences favoring one antihypertensive drug class over another truly exist, they have been singularly difficult to uncover with any consistency. Considering that multidrug therapy is required in the majority of patients with hypertension, the debate as to which drug class is best to start with is moot, in that the clinician is now more called upon to decide the best combinations of drugs and not the best monotherapy.
Entanglement Entropy Near Cosmological Singularities

We investigate the behavior of the entanglement entropy of a confining gauge theory near cosmological singularities using gauge/gravity duality. As expected, the coefficients of the UV divergent terms are given by simple geometric properties of the entangling surface in the time-dependent background. The finite (universal) part of the entanglement entropy either grows without bound or remains bounded depending on the nature of the singularity and entangling region. We also discuss a confinement/deconfinement phase transition as signaled by the entanglement entropy.
New examples of tunnel number subadditivity

Abstract If the tunnel number of a knot K is denoted t ( K ) , a pair of knots K 1 , K 2 is said to be subadditive if t ( K 1 ) + t ( K 2 ) > t ( K 1 # K 2 ) . Scharlemann and Schultens (2000) [11] defined the degeneration ratio to be d ( K 1 , K 2 ) = 1 − t ( K 1 # K 2 ) t ( K 1 ) + t ( K 2 ) , and proved that d ( K 1 , K 2 ) ⩽ 3 / 5 . However, the highest known degeneration ratio known for a pair of knots is just 2/5. We use free decompositions to construct links which experience degeneration approaching 3/7 when the connect sum is taken with certain knots. These links can be modified to yield a family of knots whose members we conjecture to have the same property.
The Synthesis and Cycloaddition Reactions of 3-Azabicyclo[3.1.0]hex-2-ene 3-oxide and 3-Azabicyclo[3.2.0]hept-2-ene 3-oxide. Highly Strained Bicyclic Nitrones

Abstract The synthesis of two strained bicyclic nitrones is described. Subsequent cycloadditions demonstrated a high degree of regiochemical and stereochemical control.
An Iterative Joint Linear-Programming Decoding of LDPC Codes and Finite-State Channels

In this paper, we introduce an efficient method for the joint linear-programming (LP) decoding of low-density parity-check (LDPC) codes and finite-state channels (FSCs). In particular, we extend the approach of iterative approximate LP decoding proposed by Vontobel and Koetter and further analyzed by Burshtein. By taking advantage of the dual-domain structure of the joint decoding LP, we obtain a convergent iterative algorithm for joint decoding. Our intent was to find an algorithm very similar to BCJR-based turbo equalization (TE) and it seems that we have succeeded in this respect. The result is an iterative solver for the joint decoding LP whose complexity is similar to TE but whose performance is similar to joint LP decoding. The main advantage of this decoder is that it appears to provide the predictability of joint LP decoding with the computational complexity of TE.
Resultants in genetic linkage analysis

Statistical models for genetic linkage analysis of k locus diseases are k-dimensional subvarieties of a (3^k-1)-dimensional probability simplex. We determine the algebraic invariants of these models with general characteristics for k=1; in particular we recover, and generalize, the Hardy-Weinberg curve. For k=2, the algebraic invariants are presented as determinants of 32x32-matrices of linear forms in nine unknowns, a suitable format for computations with numerical data.
Education and Labor Market Discrimination

Using a model of statistical discrimination and educational sorting, we explain why blacks get more education than whites of similar cognitive ability, and we explore how the Armed Forces Qualification Test (AFQT), wages, and education are related. The model suggests that one should control for both AFQT and education when compar ing the earnings of blacks and whites, in which case a substantial black-white wage differential emerges. We reject the hypothesis that differences in school quality between blacks and whites explain the wage and education differentials. Our findings support the view that some of the black-white wage differential reflects the operation of the
Synthesis and characterization of molybdenum nitride hydrodenitrogenation catalysts

Abstract Details concerning the relationships between the structural, chemical and catalytic properties of Mo nitrides have been elucidated. A series of Mo nitride catalysts were prepared by the temperature programmed reaction of MoO3 with NH3. The structural properties of these nitrides were complex functions of the heating rates and space velocities employed. Two reaction sequences were proposed to account for the synthesis of high, medium and low surface area materials. An interesting conclusion was that the degree of reduction of the molybdate precursor or intermediate governed the structural properties of the product. Some evidence is also presented to suggest that the nucleation and growth rates involved in the transformation of the oxide to the nitride were significantly influenced by the synthesis conditions. The Mo nitrides proved to be exceptional pyridine hydrodenitrogenation catalysts. Their catalytic properties were superior to those of a commercial sulfided Co-Mo hydrotreatment catalyst, having higher activities and better C-N bond hydrogenolysis selectivities. Hydrodenitrogenation over the Mo nitrides appeared to be structure-sensitive. While detailed relationships between the catalytic activity and surface stoichiometry could not be ascertained, there did appear to be a correlation between the activity, and the particle size and grain boundary length. We proposed that at least two types of HDN sites existed on the Mo nitride surfaces; modest activity sites on the particles and high activity sites at grain boundaries. The N/Mo stoichiometry of the highest activity catalyst was near unity suggesting that MoN was present perhaps localized at the grain boundaries. Finally structures near or at the surface were markedly different from those of the bulk. While the predominant bulk phase was γ-Mo2N, the surface appeared to consist of either non-stoichiometric β-Mo16N7 or mixtures of Mo and β-Mo16N7.
The synthesis of the monomeric moiety of disorazole C1

Abstract The stereocontrolled synthesis of the monomeric subunit of the macrolide dimer disorazole C 1 ( 1 ) has been accomplished by convergent coupling of 3 and 4 using the Stille method.
Vicinal functionalization of propiolate esters via catalytic carbocupration: stereoselective formation of substituted vinyl silanes.

The vicinal functionalization of propiolate esters via a catalytic carbocupration−silicon group migration sequence has been investigated. We have observed that catalyst loadings as low as 5 mol % allow for good yields and excellent diastereoselectivities (>20:1) with a series of Grignard reagents for the synthesis of substituted E-vinyl silanes.
A NOTE ON CHAMBERS'S “LONG MEMORY AND AGGREGATION IN MACROECONOMIC TIME SERIES”*

This note reviews some results on aggregating discrete-time long memory processes, providing a formula for the spectrum of the aggregates that considers the aliasing effect.
Economic Analysis in an Anthropological Setting: Some Methodological Considerations

The substantivist-formalist debate over the applicability of economics to non-Western societies may be illuminated by consideration of the nature of economic analysis. Because this analysis takes as data preferences technical production or exchange possibilities and an inventory of resources, it is shown incapable of being an exhaustive model of a society, but since these patterns interact in any human group, there is always a use for economic analysis in tracing how resources are allocated to needs, whether on a basis of maximization or of fixed targets. Applications of economic analysis to anthropologists' problems and alternative definitions of “the economy” are also considered.
Homogenization of elliptic systems with Neumann boundary conditions

The main purpose of this work is to study uniform regularity estimates for a family of elliptic operators $\{\mathcal{L}_\varepsilon, \varepsilon>0\}$, arising in the theory of homogenization, with rapidly oscillating periodic coefficients. We establish sharp $W^{1,p}$ estimates, Lipschitz estimates, and nontangential maximal function estimates, which are uniform in the parameter $\varepsilon$, on solutions with Neumann boundary conditions in $C^{1,\alpha}$ domains.
Greece in the European Union: policy lessons from two decades of membership

Abstract This paper examines the first two decades of Greece’s experience as a member of the European Union (EU). In evaluating the Greek experience within the EU, we derive three fundamental policy lessons that apply both to similar small peripheral countries now entering the EU and to the EU itself in terms of facilitating their integration in a large economic area. First, small peripheral countries that enter the EU must address the structural deficiencies of their economies before entry in order to minimize the impact of increased competition after the removal of trade protection, and follow domestic policies that maintain and promote their comparative advantage within the EU. Second, the Convergence Criteria have proven to be a successful mechanism for countries with a poor historical policy record to achieve macroeconomic stability, as shown by the case of Greece. Third, common EU policies can be very helpful in facilitating structural reforms in small peripheral economies. However, these policies must be continuously evaluated and improved so that their effectiveness is maximized.
Learning in a compiler for MINSAT algorithms

This paper describes learning in a compiler for algorithms solving classes of the logic minimization problem MINSAT, where the underlying propositional formula is in conjunctive normal form (CNF) and where costs are associated with the True/False values of the variables. Each class consists of all instances that may be derived from a given propositional formula and costs for True/False values by fixing or deleting variables, and by deleting clauses. The learning step begins once the compiler has constructed a solution algorithm for a given class. The step applies that algorithm to comparatively few instances of the class, analyses the performance of the algorithm on these instances, and modifies the underlying propositional formula, with the goal that the algorithm will perform much better on all instances of the class.
Localized coarsening of conforming all-hexahedral meshes

Finite element mesh adaptation methods can be used to improve the efficiency and accuracy of solutions to computational modeling problems. In many applications involving hexahedral meshes, localized modifications which preserve a conforming all-hexahedral mesh are desired. Effective hexahedral refinement methods that satisfy these criteria have recently become available; however, due to hexahedral mesh topology constraints, little progress has been made in the area of hexahedral coarsening. This paper presents a new method to locally coarsen conforming all-hexahedral meshes. The method works on both structured and unstructured meshes and is not based on undoing previous refinement. Building upon recent developments in quadrilateral coarsening, the method utilizes hexahedral sheet and column operations, including pillowing, column collapsing, and sheet extraction. A general algorithm for automated coarsening is presented and examples of models that have been coarsened with this new algorithm are shown. While results are promising, further work is needed to improve the automated process.
Synthesis and photophysics of a novel porphyrin-C60 hybrid

Abstract In the pursuit of a porphyrin-fullerene linked hybrid with increased solubility and superior cation complexation abilities, hybrid 1 was synthesized. The amphiphilic hybrid 1 was found to be slightly soluble in DMSO, displayed a lower affinity for metal cations than expected, and had a surprisingly high quantum yield (ΦΔ) for formation of singlet oxygen (1O2).
Efficient kinematics for jet-propelled swimming

We use computer simulations and an analytical model to study the relationship between kinematics and performance in jet-propelled jellyfish swimming. We prescribe different power-law kinematics for the bell contraction and expansion, and identify kinematics that yield high swimming speeds and/or high efficiency. In the simulations, high efficiency is found when the bell radius is a nearly linear function of time, and in a second case corresponding to ‘burst-and-coast’ kinematics. The analytical model studies the contraction phase only, and finds that the efficiency-optimizing bell radius as a function of time transitions from nearly linear (similar to the numerics) for small-to-moderate output power to exponentially decaying for large output power.
A solar cycle dependence of nonlinearity in magnetospheric activity

[1] The nonlinear dependencies inherent to the historical Kp data stream (1932–2003) are examined using mutual information and cumulant-based cost as discriminating statistics. The discriminating statistics are compared with surrogate data streams that are constructed using the corrected amplitude adjustment Fourier transform (CAAFT) method and capture the linear properties of the original Kp data. Differences are regularly seen in the discriminating statistics a few years prior to solar minima, while no differences are apparent at the time of solar maxima. These results suggest that the dynamics of the magnetosphere tend to be more linear at solar maximum than at solar minimum. The strong nonlinear dependencies tend to peak on a timescale around 40–50 hours and are statistically significant up to 1 week. Because the solar wind driver variables, VBs, and dynamical pressure exhibit a much shorter decorrelation time for nonlinearities, the results seem to indicate that the nonlinearity is related to internal magnetospheric dynamics. Moreover, the timescales for the nonlinearity seem to be on the same order as that for storm/ring current relaxation. We suggest that the strong solar wind driving that occurs around solar maximum dominates the magnetospheric dynamics, suppressing the internal magnetospheric nonlinearity. On the other hand, in the descending phase of the solar cycle just prior to solar minimum, when magnetospheric activity is weaker, the dynamics exhibit a significant nonlinear internal magnetospheric response that may be related to increased solar wind speed.
Global top-down smoke aerosol emissions estimation using satellite fire radiative power measurements

Abstract. Fire emissions estimates have long been based on bottom-up approaches that are not only complex, but also fraught with compounding uncertainties. We present the development of a global gridded (1° × 1°) emission coefficients (Ce) product for smoke total particulate matter (TPM) based on a top-down approach using coincident measurements of fire radiative power (FRP) and aerosol optical thickness (AOT) from the Moderate-resolution Imaging Spectro-radiometer (MODIS) sensors aboard the Terra and Aqua satellites. This new Fire Energetics and Emissions Research version 1.0 (FEER.v1) Ce product has now been released to the community and can be obtained from http://feer.gsfc.nasa.gov/ , along with the corresponding 1-to-1 mapping of their quality assurance (QA) flags that will enable the Ce values to be filtered by quality for use in various applications. The regional averages of Ce values for different ecosystem types were found to be in the ranges of 16–21 g MJ−1 for savanna and grasslands, 15–32 g MJ−1 for tropical forest, 9–12 g MJ−1 for North American boreal forest, and 18–26 g MJ−1 for Russian boreal forest, croplands and natural vegetation. The FEER.v1 Ce product was multiplied by time-integrated FRP data to calculate regional smoke TPM emissions, which were compared with equivalent emissions products from three existing inventories. FEER.v1 showed higher and more reasonable smoke TPM estimates than two other emissions inventories that are based on bottom-up approaches and already reported in the literature to be too low, but portrayed an overall reasonable agreement with another top-down approach. This suggests that top-down approaches may hold better promise and need to be further developed to accelerate the reduction of uncertainty associated with fire emissions estimation in air-quality and climate research and applications. Results of the analysis of FEER.v1 data for 2004–2011 show that 65–85 Tg yr−1 of TPM is emitted globally from open biomass burning, with a generally decreasing trend over this short time period. The FEER.v1 Ce product is the first global gridded product in the family of "emission factors", that is based essentially on satellite measurements, and requires only direct satellite FRP measurements of an actively burning fire anywhere to evaluate its emission rate in near-real time, which is essential for operational activities, such as the monitoring and forecasting of smoke emission impacts on air quality.
Spatially resolved stellar kinematics of field early-type galaxies at z=1 : evolution of the rotation rate

We use the spatial information of our previously published VLT/FORS2 absorption-line spectroscopy to measure mean stellar velocity and velocity dispersion profiles of 25 field early-type galaxies at a median redshift z = 0.97 (full range 0.6 < z < 1.2). This provides the first detailed study of early-type galaxy rotation at these redshifts. From surface brightness profiles from HST imaging we calculate two-integral oblate axisymmetric Jeans equation models for the observed kinematics. Fits to the data yield for each galaxy the degree of rotational support and the mass-to-light ratio M/LJeans. S0 and Sa galaxies are generally rotationally supported, whereas elliptical galaxies rotate less rapidly or not at all. Down to MB = − 19.5 (corrected for luminosity evolution), we find no evidence for evolution in the fraction of rotating early-type (E+S0) galaxies between z ~ 1 (63% ± 11% ) and the present (61% ± 5% ). We interpret this as evidence for little or no change in the field S0 fraction with redshift. We compare M/LJeans with M/Lvir inferred from the virial theorem and globally averaged quantities and assuming homologous evolution. There is good agreement for nonrotating (mostly E) galaxies. However, for rotationally supported galaxies (mostly S0) M/LJeans is on average ~40% higher than M/Lvir. We discuss possible explanations and the implications for the evolution of M/L between z = 1 and the present and its dependence on mass.
Determination of the molecular structure of sulfonyl chloride isocyanate using microwave spectroscopy

Abstract The microwave spectrum of sulfonyl chloride isocyanate has been observed with a pulsed-beam Fourier-transform microwave spectrometer. The spectra for two isotopic species, SO 2 35 ClNCO and SO 2 37 ClNCO, were assigned by considering the Stark effect and the nuclear quadrupole splittings due to chlorine and nitrogen. Rotational constants and nuclear quadrupole coupling constants were determined from the assigned transitions. The bond angles and dihedral angles were derived from the six rotational constants of the two isotopic species by imposing several constraints derived in the electron diffraction study. The present results indicate that the dihedral angle ClSNC is 94° and that the NCO group is not linear for the lowest energy conformer observed in the low-temperature supersonic beam ( T rot = 1 K).
An enzymatic synthesis of 2-azido-L-tyrosine

Abstract Tyrosine-phenol lyase-catalyzed coupling of 3-azidophenol and pyruvic acid produced 2-azido-L-tyrosine in good yield. Preliminary results indicate that this new analogue may serve as a replacement for tyrosine in several enzymatic processes.
Climatic Change on Mars

It is pointed out that Mars is the only known planet with a major atmospheric constituent condensable at typical surface temperatures. The temperatures range from 290 K at equatorial noon to a temperature at the cold pole of 145 K in polar winter. There may be three different periods of climatic variation on Mars. Aspects of reversible climatic instability might possibly explain the channels and other features suggestive of the extensive occurrence of liquid water on Mars. An aqueous epoch on Mars would have important biological and other geological implications. Putative Martian organisms which flourish in the aqueous epoch may now be in cryptobiotic repose.
[2 + 2] Cycloaddition of cyclic vinyl phosphonates with ketenes

Highly substituted cyclic β-alkoxyvinyl phosphonates underwent thermal [2+2] cycloaddition with activated ketenes to afford bicyclic phosphonates. Fragmentation of the central polarized bond of this bicyclic system occurred readily upon treatment with zinc in acetic acid, to give rise to ring expanded products. This method provides access to cycloheptane-1,3-diones substituted at the 4-position with a phosphonate group.
A Low Power Photoemission Source for Electrons on Liquid Helium

Electrons on the surface of liquid helium are a widely studied system that may also provide a promising method to implement a quantum computer. One experimental challenge in these studies is to generate electrons on the helium surface in a reliable manner without heating the cryo-system. An electron source relying on photoemission from a zinc film has been previously described using a high power continuous light source that heated the low temperature system. This work has been reproduced more compactly by using a low power pulsed lamp that avoids any heating. About 5×103 electrons are collected on 1 cm2 of helium surface for every pulse of light. A time-resolved experiment suggests that electrons are either emitted over or tunnel through the 1 eV barrier formed by the thin superfluid helium film on the zinc surface. No evidence of trapping or bubble formation is seen.
An overview of Rayleigh-Taylor instability☆

Abstract The aim of this talk is to survey Rayleigh-Taylor instability, describing the phenomenology that occurs at a Taylor unstable interface, and reviewing attempts to understand these phenomena quantitatively.
Lithium cycling in a self-assembled copper chloride-polyether hybrid electrode.

Atomic-scale integration of polyether molecules and copper(II) chloride layers in a two-dimensional perovskite affords, to the best of our knowledge, the first example of extended Li+ cycling in a metal chloride electrode. The hybrid can cycle over 200 times as a cathode in a lithium battery with an open-circuit voltage of 3.2 V. In contrast, CuCl2 alone or the precursors to the hybrid cannot be cycled in a lithium battery, demonstrating the importance of the layered, organic–inorganic architecture. This work shows that appropriate organic groups can enable Li+ cycling in inexpensive, nontoxic, metal halide electrodes, which is promising for large-scale applications.
Recent MILC spectrum results

Abstract We report on results from three spectrum calculations with staggered quarks: 1) a quenched calculation with the standard action for the gluons and quarks; 2) a quenched calculation with improved actions for both the gluons and quarks; and 3) a calculation with two flavors of dynamical quarks using the standard actions for the gluons and quarks.
Tachyon effective actions in open string theory

Abstract We argue that the Dirac–Born–Infeld (DBI) action coupled to a tachyon, that is known to reproduce some aspects of open string dynamics, can be obtained from open string theory in a certain limit, which generalizes the limit leading to the usual DBI action. This helps clarify which aspects of the full open string theory are captured by this action.
A simple, inexpensive, and effective implementation of a vision-guided autonomous robot

This paper discusses a simple, inexpensive, and effective implementation of a vision-guided autonomous robot. This implementation is a second year entrance for Brigham Young University students to the Intelligent Ground Vehicle Competition. The objective of the robot was to navigate a course constructed of white boundary lines and orange obstacles for the autonomous competition. A used electric wheelchair was used as the robot base. The wheelchair was purchased from a local thrift store for $28. The base was modified to include Kegresse tracks using a friction drum system. This modification allowed the robot to perform better on a variety of terrains, resolving issues with last year's design. In order to control the wheelchair and retain the robust motor controls already on the wheelchair the wheelchair joystick was simply removed and replaced with a printed circuit board that emulated joystick operation and was capable of receiving commands through a serial port connection. Three different algorithms were implemented and compared: a purely reactive approach, a potential fields approach, and a machine learning approach. Each of the algorithms used color segmentation methods to interpret data from a digital camera in order to identify the features of the course. This paper will be useful to those interested in implementing an inexpensive vision-based autonomous robot.
Adherent diamond-like carbon coatings on metals via plasma source ion implantation

Various techniques are currently used to produce diamond-like carbon (DLC) coatings on various materials. Many of these techniques use metallic interlayers, such as Ti or Si, to improve the adhesion of a DLC coating to a ferrous substrate. An alternative processing route would be to use plasma source ion implantation (PSII) to create a carbon composition gradient in the surface of the ferrous material to serve as the interface for a DLC coating. The need for interlayer deposition is eliminated by using a such a graded interface. A PSII approach has been used to form adherent DLC coatings on magnesium, aluminum, silicon, titanium, chromium, brass, nickel and tungsten. A PSII process tailored to create a graded interface allows deposition of adherent DLC coatings even on metals that exhibit a positive heat of formation with carbon, such as magnesium, iron, brass and nickel.