cssi/SciSciGPT-SciSciNet huggingface dataset:
The Relationship between the Circular Polarization and the Magnetic Field for Astrophysical Masers with Weak Zeeman Splitting

The relationship between the magnetic field and the circular polarization of astrophysical maser radiation due to the Zeeman effect under idealized conditions is investigated when the Zeeman splitting is much smaller than the spectral line breadth and when radiative saturation is significant. The description of the circular polarization as well as inferences about the magnetic field from the observations are clearest when the rate for stimulated emission is much less than the Zeeman splitting. The calculations here are performed in this regime, which is relevant for some (if not most) observations of astrophysical masers. We demonstrate that the Stokes V parameter is proportional to the Zeeman splitting and that the fractional linear polarization is independent of the Zeeman splitting when the ratio of the Zeeman splitting to the spectral line breadth is small—less than about 0.1. In contrast to its behavior for ordinary spectral lines, the circular polarization for masers that are at least partially saturated does not decrease with increasing angle between the magnetic field and the line of sight until they are nearly perpendicular.
Slip heterogeneity on a corrugated fault

Abstract Slip heterogeneity reflects the fundamental physics of earthquake rupture and has been attributed to strong fault patches termed asperities or barriers. We propose that variations in fault-surface orientation due to slip-parallel corrugations may act as geometric asperities and barriers, generating variations in incremental (i.e. due to a single earthquake) slip across a fault surface. We evaluate this hypothesis using observations from the Arkitsa normal fault exposure in central Greece. A scan of the Arkitsa fault surface with 1-m spatial resolution and mm-scale precision reveals corrugations made up of 1–5 m wide synforms, antiforms, and nearly planar fault sections with long axes that extend in the slip direction across the entire exposed surface. The surface is thus more than an order of magnitude smoother in the direction of slip than in the perpendicular direction. Slip-perpendicular profiles exhibit nearly self-similar scaling across the range of observed wavelengths (~ 2–50 m), whereas slip-parallel profiles are significantly smoother at shorter wavelengths (
Cavity-Containing Materials Based Upon Resorcin[4]arenes by Discovery and Design

Strategies for the design of multimolecular hosts that display recognition properties analogous to those of monomolecular predecessors are described. In particular, the bowl-shaped cavity of a molecular receptor known as resorcin[4]arene has been elaborated, using hydrogen bonds, for the construction of open and closed cavities that accommodate single and multiple guest species. Both chemical and geometric considerations derived from these studies have led us to identify host frameworks, based upon the five Platonic and 13 Archimedean solids, which have yet to be synthesized or discovered and we propose such systems as targets in chemical synthesis.
Random matrix theory and discrete moments of the Riemann zeta function

We calculate the discrete moments of the characteristic polynomial of a random unitary matrix, evaluated a small distance away from an eigenangle. Such results allow us to make conjectures about similar moments for the Riemann zeta function, and provide a uniform approach to understanding moments of the zeta function and its derivative.
The measurement of income mobility: A partial ordering approach*

Given a set of longitudinal data pertaining to two populations, a question of interest is the following: Which population has experienced a greater extent of income mobility? The aim of the present paper is to develop a systematic way of answering this question. We first put forth four axioms for income movement-mobility indices, and show that a familiar class of measures is characterized by these axioms. An unambiguous (partial) ordering is then defined as the intersection of the (complete) orderings induced by the mobility measures which belong to the characterized class; a transformation of income distributions is “more mobile” than another if, and only if, the former is ranked higher than the latter for all mobility measures which satisfy our axioms. Unfortunately, our mobility ordering depends on a parameter, and therefore, it is not readily apparent how one can apply it to panel data directly. In the second part of the paper, therefore, we derive several sets of parameter-free necessary and sufficient conditions which allow one to use the proposed mobility ordering in making unambiguous income mobility comparisons in practice.
A scalable correlation aware aggregation strategy for wireless sensor networks

Sensors-to-sink data in wireless sensor networks (WSNs) are typically characterized by correlation along the spatial, semantic, and/or temporal dimensions. Exploiting such correlation when performing data aggregation can result in considerable improvements in the bandwidth and energy performance of WSNs. In this paper, we first identify that most of the existing upstream routing approaches in WSNs can be translated to a correlation-unaware data aggregation structure - the shortest-path tree. Although by using a shortest-path tree, some implicit benefits due to correlation are possible, we show that explicitly constructing a correlation-aware structure can result in considerable performance improvement. Toward this end, we present a simple, scalable and distributed correlation-aware aggregation structure that addresses the practical challenges in the context of aggregation in WSNs. Through simulations and analysis, we evaluate the performance of the proposed approach with centralized and distributed correlation-aware and -unaware structures.
NONITERATIVE SOLUTION FOR PRESSURE IN PARABOLIC FLOWS

Parabolic flows in which the pressure variation in the streamwise (or marching) direction is unknown a priori include internal thin shear layers, shock-boundary layer interactions, and inverse boundary layers with specified displacement thickness or shear stress. The pressure is typically obtained thorough an additional iteration beyond that required to determine the velocity components (and other dependent variables). A generalized block- tridiagonal procedure is discussed in which pressure is determined within the iteration for velocity components to substantially reduce computation time. The increase in algebraic complexity in the solution procedure is small; no increase in the size of the block matrices is required. The method applies to any marching solution in which a scalar dependent variable is constant across the flow, but varies in the streamwise or marching direction.
Simulation of auroral electron acceleration by inertial Alfvén waves

[1] A two-dimensional particle code, similar to that used in the work of Swift (2007), is used to model the acceleration of auroral electrons by inertial Alfven waves. The simulation domain is 20,000 km parallel to the magnetic field and some tens of kilometers across. Effects of a variable magnetic field and magnetic mirror force are included. The Alfven wave is launched by a moving bipolar potential waveform with peak amplitudes of ±200 V imposed at the top of the simulation domain. Electrons are accelerated to 3 keV energy. Two types of acceleration processes are seen: one is impulsive acceleration from shock structures, and the other is from weaker parallel electric fields extending over several thousand kilometers. The shock structures are very small, and electrons accelerated by these structures can produce auroral forms with thicknesses considerably smaller than an electron inertial length. Electrons also tend to undergo multiple acceleration events. Electrons are more strongly accelerated upward. Half of these are destined to precipitate in the opposite hemisphere, and half are destined to become trapped. This implies that much of the aurora seen in the Northern Hemisphere is due to electrons accelerated in the Southern Hemisphere. The simulations also suggest that auroral acceleration processes provide a likely source for radiation belt particles.
Kosterlitz-Thouless Transition in Finite-Size BEC Systems

The Kosterlitz-Thouless (KT) transition in two-dimensional BEC systems is calculated taking into account the fact that in experiments these are finite-size systems. The outer boundaries of the condensate effectively act as hard walls, and this has a polarizing effect on the vortex pairs of the KT transition, causing the superfluid fraction to become strongly anisotropic. The decreased pair energy near the walls results in a strongly enhanced vortex density near the boundaries. Since the pair density can now be directly measured, we extend here our previous calculations to include the vortex density as a function of the distance from the boundaries. Possible experiments using sound propagation in the gases are proposed to probe the anisotropic properties of the superfluid density, including an unusual sharp dip in the superfluid density that is predicted to occur down the middle of a long superfluid strip.
ON A THEOREM IN MULTI-PARAMETER POTENTIAL THEORY

We prove that the expected Lebesgue measure of the range of an additive Levy process is positive if and only if the product $\Re([1+\Psi_1(\xi)]^{-1})...\Re([1+\Psi_N(\xi)]^{-1})$ is integrable. This was previously proved by Khoshnevisan, Xiao and Zhong [1] under a sector condition.
Oxidative dimerization of methane over sodium-promoted calcium oxide

Abstract Sodium-promoted calcium oxides are active and selective catalysts for the partial oxidation of methane to ethane and ethylene using molecular oxygen as an oxidant. In a conventional fixed-bed flow reactor, operating at atmospheric pressure, a 45% C 2 (sum of ethane and ethylene) selectivity was achieved at a 33% methane conversion over 2.0 g of 15 wt% Na CaO catalyst at 725 °C with a gas mixture of CH 4 O 2 = 2 . The other products were CO, CO 2 , and H 2 . EPR results indicated that [Na + O − ] centers in Na CaO are responsible for the catalytic production of CH 3 · from methane via hydrogen atom abstraction. These CH 3 · radicals dimerize, primarily in the gas phase, to form C 2 H 6 , which further oxidizes to C 2 H 4 . Increasing temperatures reverse the gas-phase equilibrium CH 3 · + O 2 ⇄ CH 3 O 2 · to produce more CH 3 · and increase the C 2 selectivity. The CH 3 O 2 · eventually is converted to carbon oxides under the reaction conditions employed; therefore, increasing O 2 pressures decrease the C 2 selectivity. There is evidence that CH 3 O 2 · in the presence of C 2 H 6 initiates a chain reaction that enhances the methane conversion. The addition of Na + to CaO also reduces the surface area of the catalysts, thus minimizing a nonselective oxidation pathway via surface methoxide intermediates.
Construction of energy preserving QMF

A new perfect reconstruction quadrature mirror filter banks with finite impulse response filters are constructed from systems of biorthogonal refinable functions and wavelets with the Condition energy preservation. The most significant feature of these filter banks is that filters preserve energy very well. Based on the efficient constructing algorithm, odd-length filter banks are constructed for applications in image processing.
Foreign Aid Policy and Sources of Poverty: A Quantitative Framework

The econometric literature has been unable to establish a robust association between foreign aid and growth and poverty reduction. In this paper, we argue that aid effectiveness must be assessed using methods that go beyond cross-country regressions. We calibrate a dynamic general equilibrium model that is capable of generating large sustained income gaps between rich and poor countries. The model quantifies three sources of poverty: (1) lack of access to international capital, (2) low schooling and high fertility (a poverty trap), and (3) an antigrowth domestic fiscal policy set by an elite. We analyze policies designed to address each source of poverty and compare the aid cost of their implementation. The policies differ dramatically in the extent and timing of their growth effects, and in the aid cost of their implementation.
A timing model for the revised simplex method

It is shown that the time spent in a widely implemented version of the revised simplex method for linear programming can be modeled as the classic inventory control system. Using an Economic Order Quantity (EOQ) formula, an approximation to the optimal frequency for basis refactorization can be inferred. Such timing models can be used to significantly reduce the cost of routine applications as well as to predict the performance of new variants of the algorithm.
Click Chemistry‐Led Advances in High Content Functional Proteomics

The availability of complete genome sequences for numerous eukaryotic and prokaryotic organisms has inspired the advent of new methods to functionally characterize proteins on a global scale. Chemical approaches, in particular, have emerged as a powerful way to investigate the proteome, providing small-molecule probes that report on protein activity and Post-Translational Modification (PTM) state directly in complex biological samples. Many of the key advances made in chemical proteomics can be attributed to the development of efficient bio-orthogonal reactions such as the copper (I)-catalyzed Huisgen's azide–alkyne cycloaddition, a reaction commonly known as “Click Chemistry” (CC). The generation of “clickable” proteomics probes has removed the requirement for bulky reporter tags, thereby allowing access to more biologically relevant systems such as live cells or animals. The versatility of CC has also allowed for greater experimental efficiency, as different reporter tags (i.e., a fluorophore for detection or biotin for enrichment) can be appended to a single probe. Such advances have enabled researchers to identify protein activities dysregulated in disease states, assess the selectivity of enzyme inhibitors in vivo, and inventory specific PTMs on a proteome-wide scale.
Re-entering Europe: Does European Union candidacy boost foreign direct investment?

This study examines the ability of the Central and Eastern European countries to attract foreign direct investment during the first decade of transition. After considering a model of profit maximizing firms, we undertake an empirical investigation of the factors that determine multinational firms’ location decisions within Europe. We find empirical support for the traditional market size and cost factors. In addition, we examine the effect of key European Union announcements regarding the accession process. Results indicate that the announcements had statistically significant and quantitatively important effects on foreign direct investment in the Central and Eastern European candidate countries.
The tax implications of cost shifting in cost-benefit analysis in mental health

This paper examines the tax implications of systems of care for psychiatric patients that rely more on the provision of services in the community rather than in state hospitals. State governments pay the costs of patient care in state hospitals, but share costs with the federal government (via Medicaid) for community based care. Taxes create distortions as gauged by the marginal cost of public funds (MCF). Since state and federal governments use different tax mixes, one needs a MCF for each form of government to evaluate system changes. Separate estimates of the MCF for each state in the USA are derived. Only for Alaska is cost shifting welfare improving.
Modeling of Local Edge Plasma Perturbations Induced by a Biased Probe

The Langmuir probe is a standard diagnostic tool for laboratory plasmas, routinely used for edge plasmas in magnetic fusion devices. However, recent studies on the Alcator C-Mod tokamak indicate the possibility of a substantial local plasma perturbation by a negatively biased divertor plate target probe under high recycling conditions when the electron temperature is under ∼10 eV. The effects of the probe perturbation of the plasma are studied using the tokamak edge plasma code UEDGE for parameters relevant to Alcator C-Mod edge. It is found that at sufficiently negative bias voltage, the probe substantially modifies the local plasma characteristics. In particular, this is relevant to the experimentally known “death-ray” phenomenon, where the plasma pressure near the probe strongly exceeds the upstream value. Certain features of the “death-ray” phenomenon are reproduced in the modeling, pointing to interplay of plasma and neutrals transport, atomic physics, and sheath heat-flux boundary conditions (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Stochastic Models of Quasigeostrophic Turbulence

Atmospheric and oceanic eddies are believed to be manifestations of quasigeostrophic turbulence — turbulence that occurs in rapidly rotating, vertically stratified fluid systems. The heat, momentum, and water transport by these eddies constitute a significant component of the climate balance, without which climate change cannot be understood. A major, unsolved problem is whether the turbulent eddy fluxes can be parameterized in terms of the large-scale, background flow. In the past, stochastic models have been used quite extensively to investigate quasigeostrophic turbulence in the case in which the eddy statistics are isotropic and homogeneous. Unfortunately, these models ignore the background shear which is absolutely essential to maintaining the eddies in the presence of dissipation. Recent attempts to extend stochastic models to shear flows have shown significant skill in predicting the structure of the eddy fluxes in arbitrary, three-dimensionally varying flows. This paper provides an accessible introduction to these models. The topics reviewed include quasigeostrophic turbulence and two-dimensional turbulence, non-modal andoptimal perturbations, mathematical theory of stochastic models, stochastic model simulations with realistic background states, and recent closure theories. A list of unsolved problems concludes this review.
IGF-1R Modulation of Acute GH-Induced STAT5 Signaling: Role of Protein Tyrosine Phosphatase Activity

GH is a potent anabolic and metabolic factor that binds its cell surface receptor (GHR), activating the GHR-associated tyrosine kinase, Janus kinase 2, which phosphorylates and activates the latent transcription factor, signal transducer and activator of transcription 5 (STAT5). Some GH actions are mediated by the elaboration of IGF-1, which exerts effects by binding and activating the heterotetrameric tyrosine kinase growth factor receptor, IGF-1R. In addition to this GH-GHR-IGF-1-IGF-1R scheme, we have demonstrated in primary osteoblasts and in islet β-cells that then deletion or silencing of IGF-1R results in diminished GH-induced STAT5 phosphorylation, suggesting that the presence of IGF-1R may facilitate GH signaling. In this study, we explore potential roles for protein tyrosine phosphatase activity in modulating GH-induced signaling, comparing conditions in which IGF-1R is present or diminished. We confirm that in mouse primary osteoblasts harboring loxP sites flanking the IGF-1R gene, infection with an adenovirus that expresses the Cre recombinase results in IGF-1R deletion and diminished acute GH-induced STAT5 phosphorylation. Furthermore, we present a new model of IGF-1R silencing, in which expression of short hairpin RNA directed at IGF-1R greatly reduces IGF-1R abundance in LNCaP human prostate cancer cells. In both models, treatment with a chemical inhibitor of protein tyrosine phosphatase-1B (PTP-1B), but not one of src homology region 2 domain-containing phosphotase-1 (SHP-1) and SHP-2, reverses the loss of GH-induced STAT5 phosphorylation in cells lacking IGF-1R but has no effect in cells with intact IGF-1R. Furthermore, expression of either a dominant-negative PTP-1B or the PTP-1B-interacting inhibitory protein, constitutive photomorphogenesis 1, also rescues acute GH-induced STAT5 signaling in IGF-1R-deficient cells but has no effect in IGF-1R replete cells. By expressing a substrate-trapping mutant PTP-1B, we demonstrate that tyrosine phosphorylated Janus kinase-2 is a PTP-1B substrate only in cells lacking IGF-1R. Collectively, our data suggest that IGF-1R positively regulates acute GH signaling by preventing access of PTP-1B activity to Janus kinase 2 and thereby preventing PTP-1B-mediated suppression of GH-induced STAT5 activation.
Deletion without rebalancing in multiway search trees

Some database systems that use a form of B-tree for the underlying data structure do not do rebalancing on deletion. This means that a bad sequence of deletions can create a very unbalanced tree. Yet such databases perform well in practice. Avoidance of rebalancing on deletion has been justified empirically and by average-case analysis, but to our knowledge, no worst-case analysis has been done. We do such an analysis. We show that the tree height remains logarithmic in the number of insertions, independent of the number of deletions. Furthermore, the amortized time for an insertion or deletion, excluding the search time, is O(1), and nodes are modified by insertions and deletions with a frequency that is exponentially small in their height. The latter results do not hold for standard B-trees. By adding periodic rebuilding of the tree, we obtain a data structure that is theoretically superior to standard B-trees in many ways. Our results suggest that rebalancing on deletion not only is unnecessary but may be harmful.
Direct Ruthenium-Catalyzed C−C Coupling of Ethanol: Diene Hydro-hydroxyethylation To Form All-Carbon Quaternary Centers

Under ruthenium-catalyzed transfer hydrogenation conditions, direct C−C coupling of ethanol and 2-substituted dienes occurs to furnish products of hydro-hydroxyethylation: anti-configured neopentyl homoallylic alcohols. Identical adducts are generated from acetaldehyde under related conditions employing isopropanol as reductant.
The harmonic mean curvature flow of nonconvex surfaces in $${\mathbb{R}^3}$$

We consider a compact star-shaped mean convex hypersurface \({\Sigma^2\subset \mathbb{R}^3}\). We prove that in some cases the flow exists until it shrinks to a point. We also prove that in the case of a surface of revolution which is star-shaped and mean convex, a smooth solution always exists up to some finite time T < ∞ at which the flow shrinks to a point asymptotically spherically.
Dominance Relations and Breeding Rate in Mature Male American Bison

The assumption of a linear dominance hierarchy accounted for 78% of the outcomes of aggressive interactions in a group of 26 mature male American bison (Bison bison) during a breeding season. All recorded interactions between bulls were initiated aggressively, and 88% of all interactions were won by the initiator. The dominant-subordinant roles were reversed at least once in most dyads during the three weeks. Neither age nor body weight were correlated with high social standing. Bulls with higher social standing had higher breeding rates.
Use of asthma medication dispensing patterns to predict risk of adverse health outcomes: a study of Medicaid-insured children in managed care programs.

Background Regular use of inhaled anti-inflammatory (AI) medication improves outcomes for children with persistent asthma. Objective To relate 3 measures of asthma medication dispensing to physical health and hospital-based events among children with asthma who were enrolled in 1 of 5 managed care health plans. Methods Parents of Medicaid-insured children with asthma were interviewed at baseline and 1-year follow-up. Utilization data were collected from the health plans in which the children were enrolled. Subjects were stratified into 3 subgroups according to asthma severity: intermittent asthma; persistent asthma for which β-agonist (BA) medication was dispensed infrequently (≤3 times per year); and persistent asthma for which BA medication was dispensed frequently (≥4 times per year). Results Baseline interviews were completed by 1,663 parents (63% response rate), 1,504 of whom were enrolled in their health plan for at least 11 months during the baseline year. Follow-up interviews were completed by 1,287 (86%) of the 1,504 parents. Among the subgroup of children with persistent asthma for whom BA was dispensed frequently, those who had 1 to 3 AI dispensings had a greater risk for hospital-based events than those with 6 or more AI dispensings. Baseline-year AI medication utilization patterns were not associated with follow-up-year outcomes. No clinically meaningful association was found in subgroups with less severe asthma; however, few AI medications were dispensed to these children. Conclusions Policymakers and clinicians who wish to use medication-based measures to evaluate quality of asthma care should consider counting the number of times AI medication is dispensed among children with more severe asthma.
Chiral models of weak scale supersymmetry

Abstract I discuss supersymmetric extensions of the Standard Model containing an extra U (1)′ gauge symmetry which provide a solution to the μ -problem and at the same time protect the proton from decaying via dimension 4 operators. Moreover, all fields are protected by chirality and supersymmetry from acquiring high scale masses. The additional requirements of anomaly cancellation and gauge coupling unification imply the existence of extra matter multiplets and that several fields participate in U (1)′ symmetry breaking simultaneously. While there are several studies addressing subsets of these requirements, this work uncovers simultaneous solutions to all of them. It is surprising and encouraging that extending the Minimal Supersymmetric Standard Model by a simple U (1) factor solves its major drawbacks with respect to the non-supersymmetric Standard Model, especially as current precision data seem to offer a hint to the existence of its corresponding Z ′ boson. It is also remarkable that there are many solutions where the U (1)′ charges of the known quarks and leptons are predicted to be identical to those E 6 motivated Z ′ bosons which give the best fit to the data. I discuss the solutions to these constraints including some phenomenological implications.
The role of varying information quantity in ads on immediate and enduring cross-media synergies

Advertisers are increasingly incorporating online and offline media in their marketing communication plans to leverage synergies across them. However, if there are no differences in modality, it is unclear if mixed online–offline media usage can lead to cross-media synergies. The author draws from research on priming and two-factor theory of repetition to argue that varying information quantity on ads in different media leads to differences in ad processing at initial exposures, which impacts how information-processing capacity is allocated on retrieval vs. encoding activities on later exposures. This research compares the effect of combined online–offline media usage [Internet banner–print magazine–permission email (I–P–E) or email ad–print ad–Internet banner(E–P–I)] vs. single-media usage (I–I–I, E–E–E, and P–P–P) on aided and unaided brand information recall and brand attitude. Experimental data show that mixed-media use with increasing brand information (I–P–E) has a synergistic effect leading to sign...
A Fuzzy Logic Controlled Bridge Type Fault Current Limiter for Transient Stability Augmentation of Multi-Machine Power System

This paper proposes a fuzzy logic controlled bridge type fault current limiter (FCL) to enhance the transient stability of multi-machine power systems. The transient stability performance of the fuzzy logic controlled bridge type FCL is compared with that of another static nonlinear controlled bridge type FCL. The total kinetic energy (TKE) of the generators in the system is used to determine the transient stability enhancement index. Also, the critical clearing time has been presented as a stability limit. Instead of conventional reclosing, the optimal reclosing of circuit breakers is considered. Simulations are performed by using the Matlab/Simulink software. Simulation results of both permanent and temporary faults at different points of the IEEE 30-bus power system indicate that the fuzzy logic controlled bridge type FCL can enhance the transient stability of the system well. Also, the performance of the proposed fuzzy logic controller is better than that of the static nonlinear controller.
Testing low-degree polynomials over prime fields

We present an efficient randomized algorithm to test if a given function f : F pn → Fp (where p is a prime) is a low-degree polynomial. This gives a local test for Generalized Reed-Muller codes over prime fields. For a given integer t and a given real e > 0, the algorithm queries f at O($ O({{1}\over{\epsilon}}+t.p^{{2t \over p-1}+1}) $) points to determine whether f can be described by a polynomial of degree at most t. If f is indeed a polynomial of degree at most t, our algorithm always accepts, and if f has a relative distance at least e from every degree t polynomial, then our algorithm rejects f with probability at least $ {1\over 2} $. Our result is almost optimal since any such algorithm must query f on at least $ \Omega ( {1 \over \epsilon} + p^ {t+1 \over p-1})$ points. © 2009 Wiley Periodicals, Inc. Random Struct. Alg., 2009 A preliminary version of this paper appeared in 45th Symposium on Foundations of Computer Science, 2004. Most of this work was done while the author (Patthak) was at the University of Texas at Austin. This work was done while the author (Rudra) was at the University of Texas at Austin.
Ancestor ideals of vector spaces of forms, and level algebras

Let R=k[x1,…,xr] denote the polynomial ring in r variables over a field k, with maximal ideal M=(x1,…,xr), and let V⊂Rj denote a vector subspace of the space Rj of degree-j homogeneous elements of R. We study three related algebras determined by V. The first is the ancestor algebra Anc(V)=R/V whose defining ancestor ideal V is the largest graded ideal of R such that V∩Mj=(V), the ideal generated by V. The second is the level algebra LA(V)=R/L(V) whose defining ideal L(V), is the largest graded ideal of R such that the degree-j component L(V)∩Rj is V; and third is the algebra R/(V). We have that L(V)=V+Mj+1. When r=2 we determine the possible Hilbert functions H for each of these algebras, and as well the dimension of each Hilbert function stratum. We characterize the graded Betti numbers of these algebras in terms of certain partitions depending only on H, and give the codimension of each stratum in terms of invariants of the partitions. We show that when r=2 and k is algebraically closed the Hilbert function strata for each of the three algebras attached to V satisfy a frontier property that the closure of a stratum is the union of more special strata. In each case the family G(H) of all graded ideals of the given Hilbert function is a natural desingularization of this closure. We then solve a refinement of the simultaneous Waring problem for sets of degree-j binary forms. Key tools throughout include properties of an invariant τ(V), the number of generators of V⊂k[x1,x2], and previous results concerning the projective variety G(H) in [Mem. Amer. Math. Soc., Vol. 10 (188), 1977].
Staged Repair of Benign Tracheo-Neo-Esophageal Fistula 12 Years After Esophagectomy for Esophageal Cancer

Benign tracheo-neo-esophageal fistula is a rare complication after esophagectomy. We report a 60-year-old man who presented 12 years after a McKeown esophagectomy with a fistula between the tracheal carina and the gastric conduit. In view of his severe sepsis and profound malnutrition, he underwent placement of a silicon Y-stent with a successful three-stage surgical repair consisting of duodenal exclusion with drainage gastrostomy. Six weeks later, the patient had closure of the fistula through a right thoracotomy. He finally underwent Roux-en-Y gastro-jejunostomy through a left thoraco-abdominal approach to restore the gastrointestinal continuity. Eighteen months postoperatively, he reports no dysphagia and has regained his premorbid weight.
Scoring Ensembles of Docked Protein:Ligand Interactions for Virtual Lead Optimization

Ensembles of protein structures to simulate protein flexibility are widely used throughout several applications including virtual lead optimization where they have been shown to improve ligand ranking. Yet, there is no established convention for weighting individual scores generated from ensemble members. To investigate the best method for weighting ensemble scores for proper ligand ranking, a series of dihydrofolate reductase inhibitors was docked to ensembles of Candida albicans dihydrofolate reductase (CaDHFR) structures created from a molecular dynamics (MD) simulation. From a single MD simulation, two ensemble collections were generated, one of which was subjected to a minimization procedure to create a group of structures of equal probability. As expected, ligand ranking accuracy was significantly improved when Boltzmann weighting was applied to the energies of the ensemble without structural minimization (60%), relative to that achieved with averaging (36%). However, accuracy was further improved (...
Multidisciplinary heat generating logic block placement optimization using genetic algorithm

A multidisciplinary optimization methodology for placement of heat generating semiconductor logic blocks on integrated circuit chips is presented. The methodology includes thermal and wiring length criteria, which are optimized simultaneously using a genetic algorithm. An effective thermal performance prediction methodology based on a superposition method is used to determine the temperature distribution on a silicon chip due to multiple heat generating logic blocks. Using the superposition method, the predicted temperature distribution in the silicon chip is obtained in much shorter time than with a detailed finite element model and with comparable accuracy. The main advantage of the present multidisciplinary design and optimization methodology is its ability to handle multiple design objectives simultaneously for optimized placement of heat generating logic blocks. Capabilities of the present methodology are demonstrated by applying it to several standard benchmarks. The multidisciplinary logic block placement optimization results indicate that the maximum temperature on a silicon chip can be reduced by up to 7.5^oC, compared to the case in which only the wiring length is minimized.
New bis-lactam chiral auxiliaries for nitrile oxide cycloadditions

Abstract Two “pseudoenantiomeric” bis lactam chiral auxiliaries are introduced for use in asymmetric nitrile oxide cycloaddition reactions with derived acrylimides. Outstanding selectivities in the nitrile oxide cycloadditions (99/1) are not duplicated in other related reactions.
Numerical Simulation of Sea-floor Spreading

A two-dimensional time-dependent method that allows large viscosity variations is used to numerically simulate upper mantle convection, including lithospheric plate motion. The numerical operator developed for viscous flow is in self-adjoint form, so that the conjugate gradient iteration method can be used. Convergence is faster than with relaxation methods. The method is applied to sea-floor spreading with the objective of examining the driving mechanism of mid-ocean ridges. In accordance with this objective, deep convection is suppressed in the model. Counterflow below the plates is confined to depths less than 340 km. The model is fit to observed topography at four different ridge locations. It is found that, for a spreading velocity of 1.2 cm/yr, the ridge can produce compressive stress in the lithosphere out to a distance of 1600 km. For a spreading velocity of 6 cm/yr, this model is clearly excluded, for it requires excessively large stress in the lithosphere. Therefore, upwelling material must cross the seismic discontinuity at 400-km depth.
Algorithms for recognizing knots and 3-manifolds

Author(s): Hass, Joel | Abstract: This is a survey paper on algorithms for solving problems in 3-dimensional topology. In particular, it discusses Haken's approach to the recognition of the unknot, and recent variations.
Cosmic microwave background tests of inflation

Abstract Inflation provides a unified paradigm for understanding the isotropy of the cosmic microwave background (CMB), the flatness problem, and the origin of large-scale structure. Although the physics responsible for inflation is not yet well understood, slow-roll inflation generically makes several predictions: a flat Universe, primordial adiabatic density perturbations, and a stochastic gravity-wave background. Inflation further predicts specific relations between the amplitudes and shapes of the spectrum of density perturbations and gravity waves. There are now excellent prospects for testing precisely these predictions with forthcoming CMB temperature and polarization maps. Here I discuss these new CMB tests of inflation.
Rh(I)-Catalyzed Direct Arylation of Azines

The Rh(I)-catalyzed direct arylation of azines has been developed. Quinolines and 2-substituted pyridines couple with aryl bromides to efficiently afford ortho-arylated azine products using the commercially available and air-stable catalyst [RhCl(CO)2]2. Electron-deficient and electron-rich aromatic bromides couple in good yields, and hydroxyl, chloro, fluoro, trifluoromethyl, ether, and ketone functionalities are compatible with the reaction conditions. Aroyl chlorides also serve as effective azine coupling partners to give ortho-arylation products via a decarbonylation pathway.
Structural properties and tractability results for linear synteny

Abstract The syntenic distance between two species is the minimum number of fusions, fissions, and translocations required to transform one genome into the other. The linear syntenic distance, a restricted form of this model, has been shown to be close to the syntenic distance. Both models are computationally difficult to compute and have resisted efficient approximation algorithms with non-trivial performance guarantees. In this paper, we prove that many useful properties of syntenic distance carry over to linear syntenic distance. We also give a reduction from the general linear synteny problem to the question of whether a given instance can be solved using the maximum possible number of translocations. Our main contribution is an algorithm exactly computing linear syntenic distance in nested instances of the problem. This is the first polynomial time algorithm exactly solving linear synteny for a non-trivial class of instances. It is based on a novel connection between the syntenic distance and a scheduling problem that has been studied in the operations research literature.
SEVA: Sensor-enhanced video annotation

In this article, we study how a sensor-rich world can be exploited by digital recording devices such as cameras and camcorders to improve a user's ability to search through a large repository of image and video files. We design and implement a digital recording system that records identities and locations of objects (as advertised by their sensors) along with visual images (as recorded by a camera). The process, which we refer to as Sensor-Enhanced Video Annotation (SEVA), combines a series of correlation, interpolation, and extrapolation techniques. It produces a tagged stream that later can be used to efficiently search for videos or frames containing particular objects or people. We present detailed experiments with a prototype of our system using both stationary and mobile objects as well as GPS and ultrasound. Our experiments show that: (i) SEVA has zero error rates for static objects, except very close to the boundary of the viewable area; (ii) for moving objects or a moving camera, SEVA only misses objects leaving or entering the viewable area by 1--2 frames; (iii) SEVA can scale to 10 fast-moving objects using current sensor technology; and (iv) SEVA runs online using relatively inexpensive hardware.
Corrections to the Central Limit Theorem for Heavy-tailed Probability Densities

Classical Edgeworth expansions provide asymptotic correction terms to the Central Limit Theorem (CLT) up to an order that depends on the number of moments available. In this paper, we provide subsequent correction terms beyond those given by a standard Edgeworth expansion in the general case of regularly varying distributions with diverging moments (beyond the second). The subsequent terms can be expressed in a simple closed form in terms of certain special functions (Dawson’s integral and parabolic cylinder functions), and there are qualitative differences depending on whether the number of moments available is even, odd, or not an integer, and whether the distributions are symmetric or not. If the increments have an even number of moments, then additional logarithmic corrections must also be incorporated in the expansion parameter. An interesting feature of our correction terms for the CLT is that they become dominant outside the central region and blend naturally with known large-deviation asymptotics when these are applied formally to the spatial scales of the CLT.
A duality between string topology and the fusion product in equivariant K-theory

Let $G$ be a compact Lie group. Let $G \to E \to M$ be a principal $G$-bundle over a closed manifold $M$, and $G \to Ad(E) \to M$ its adjoint bundle. In this paper we describe a new Frobenius algebra structure on $h_*(Ad(E)),$ where $h_*$ is an appropriate generalized homology theory. Recall that a Frobenius algebra has both a product and a coproduct. The product in this new Frobenius algebra is induced by the string topology product. In particular, the product can be defined when $G$ is any topological group and in the case that $E$ is contractible it is precisely the Chas-Sullivan string product on $H_*(LM).$ We will show that the coproduct is induced by completing the untwisted Freed-Hopkins-Teleman fusion product. Indeed, when $M$ is replaced by $BG$ and $h_*$ is $K$-theory the coproduct is the completion of the Freed-Hopkins-Teleman fusion structure. We will then show that this duality between the string and fusion products is realized by a Spanier-Whitehead duality between certain Thom spectra of virtual bundles over $Ad(E)$.
LISA long-arm interferometry

The Laser Interferometer Space Antenna (LISA) will observe gravitational radiation in the millihertz band by measuring picometer-level fluctuations in the distance between drag-free proof masses over baselines of approximately 5 × 109m. The measurement over each baseline will be divided into three parts: two 'short-arm' measurements between the proof masses and a fiducial point on their respective spacecraft, and a 'long-arm' measurement between fiducial points on separate spacecraft. This work focuses on the technical challenges associated with these long-arm measurements and the techniques that have been developed to overcome them.
Political Power, Fiscal Crises, and Decentralization in Latin America: Federal Countries in Comparative Perspective (and some Contrasts with Unitary Cases)

What factors shape decentralization processes in Latin American federations? This work reviews and statistically analyzes current approaches on the topic, questions some claims of generality in their theoretical frameworks, and presents an argument to explain variation in decentralization processes across these federations. The main hypothesis is that the degree of decentralization (in fiscal and administrative terms) in Latin American federations has been shaped by the political power of the national executive and sub-national actors and the fiscal context in which they interact. The article presents statistical evidence (for federal and unitary countries between 1979 and 1998) to sustain some of the expectations in the argument and discusses some of its limitations.
Boundary flows in minimal models

Abstract We discuss in this paper the behaviour of minimal models of conformal theory perturbed by the operator Φ13 at the boundary. Using the RSOS restriction of the sine-Gordon model, adapted to the boundary problem, a series of boundary flows between different set of conformally invariant boundary conditions are described. Generalizing the “staircase” phenomenon discovered by Al. Zamolodchikov, we find that an analytic continuation of the boundary sinh-Gordon model provides a flow interpolating not only between all minimal models in the bulk, but also between their possible conformal boundary conditions. In the particular case where the bulk sinh-Gordon coupling is turned to zero, we obtain a boundary roaming trajectory in the c=1 theory, that interpolates between all the possible spin s Kondo models.
Respondent Experience and Contingent Valuation of Environmental Goods

Abstract Respondent experience (i.e., a respondent's information set) has long been suspected to influence contingent valuation estimates of environmental values. We assess the influence of experience by explicitly modeling the relationship between respondent experience and both fitted individual resource values and the conditional variance of these estimated values. Using three different joint specifications for experience and WTP—normal/censored-normal, Poisson/censored-normal, and zero-inflated Poisson/censored-normal—we find discrete jumps in resource values as experience increases from zero and that more-experienced respondents have smaller conditional variances. Simulation of arbitrary levels of experience allows standardization of the amount of information when developing welfare estimates.
Crown Nucleoside Monophosphate Diesters: a New Class of Nucleoside Prodrugs

Abstract An ionophore-nucleotide conjugate is proposed as a new class of nucleoside prodrug. Specifically, 5′-phosphate diester derivatives of the anti-HIV agents AZT (3′-azido-3′-deoxythymidine) and DDU (2′,3′-dideoxyuridine) were prepared with a crown ether as the phosphate masking group. Biological testing of these prodrugs revealed they had moderate anti-HIV activity.
An Architecture for the Integration of Physical and Informational Spaces

AbstractWhile computer processing power, storage capacity, and bandwidth are continuing to experience exponential growth, individual human processing capabilities are not increasing significantly. Pervasive computing offers an opportunity for applications to interact with the physical environment and to provide a task-centric and mobile infrastructure for the user. However, this rich environment can also be distracting, in part because of a lack of convergence between the physical infrastructure observed by users and the information space seen by applications. In this paper we introduce AIPIS, an architecture that bridges the physical and informational realms of the human and the computer, respectively. The purpose of AIPIS is two-fold: (1) provide users with a hands-free computing environment that automates much of the drudgery associated with the use of computers; and (2) require human attention for only critical aspects of task execution that require their input. We also describe the Aura desktop, a first prototype of the AIPIS architecture.