cssi/SciSciGPT-SciSciNet huggingface dataset:
Review of physics results from the Tevatron: Heavy flavor physics

We present a review of heavy flavor physics results from the CDF and DO Collaborations operating at the Fermilab Tevatron Collider. A summary of results from Run 1 is included, but we concentrate on legacy results of charm and b physics from Run 2, including results up to Summer 2014.
Inside money, credit, and investment

This paper presents a monetary explanation for several business-cycle facts: (i) household and business investment are procyclical, (ii) business investment lags household investment, (iii) household investment is positively correlated with M1, and (iv) household credit outstanding is positively correlated with and more volatile than household investment. We develop a dynamic general equilibrium model that features financial intermediaries accepting deposits and providing loans, credit-producing firms, and inside (bank-created) money. It is shown that the transmission of monetary shocks facilitated by credit and inside money creation is able to reconcile these real and monetary observations regarding the cyclical behavior of investment.
Time to Change What to Sow: Risk Preferences and Technology Adoption Decisions of Cotton Farmers in China

This paper examines the role of individual risk attitudes in the decision to adopt a new form of agricultural biotechnology in China. I conducted a survey and a field experiment to elicit the risk preferences of Chinese farmers, who faced the decision of whether to adopt genetically modified Bt cotton a decade ago. In my analysis, I expand the measurement of risk preferences beyond expected utility theory to incorporate prospect theory. I find that farmers who are more risk averse or more loss averse adopt Bt cotton later. Farmers who overweight small probabilities adopt Bt cotton earlier.
Approximation and Inversion of a Complex Meteorological System via Local Linear Filters

Abstract Dynamical models involving systems of numerous differential equations are commonly used to describe meteorological behavior. Approximations to such systems are often desired, particularly for inversion problems when the model’s adjoint is unavailable. A method for approximating a general, nonlinear system is explored here. The method is particularly useful for inverse problems. An application to a complex multivariate dynamic model for southern California air quality is given, and the method is shown to provide satisfactory estimates of vehicle emission-rate inputs using ozone concentration estimates for the Los Angeles basin.
Subseasonal SST Variability in the Tropical Eastern North Pacific during Boreal Summer

Boreal summer intraseasonal (30–90-day time scale) sea surface temperature (SST) variability in the east Pacific warm pool is examined using Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) sea surface temperatures during 1998–2005. Intraseasonal SST variance maximizes at two locations in the warm pool: in the vicinity of 9°N, 92°W near the Costa Rica Dome and near the northern edge of the warm pool in the vicinity of 19°N, 108°W. Both locations exhibit a significant spectral peak at 50–60-day periods, time scales characteristic of the Madden–Julian oscillation (MJO). Complex empirical orthogonal function (CEOF) and spectra coherence analyses are used to show that boreal summer intraseasonal SST anomalies are coherent with precipitation anomalies across the east Pacific warm pool. Spatial variations of phase are modest across the warm pool, although evidence exists for the northward progression of intraseasonal SST and precipitation anomalies. Intraseasonal SSTs at the north edge of the warm pool lag those in the vicinity of the Costa Rica Dome by about 1 week. The MJO explains 30%–40% of the variance of intraseasonal SST anomalies in the east Pacific warm pool during boreal summer. Peak-to-peak SST variations of 0.8°–1.0°C occur during MJO events. SST is approximately in quadrature with MJO precipitation, with suppressed (enhanced) MJO precipitation anomalies leading positive (negative) SST anomalies by 7–10 days. Consistent with the CEOF and coherence analyses, MJO-related SST and precipitation anomalies near the Costa Rica Dome lead those at the northern edge of the warm pool by about 1 week.
Shape Fluctuations of a Droplet Containing a Polymer

We consider the problem of an ideal polymer confined in a droplet. When the droplet radius is smaller than the (unconfined) polymer radius of gyration, the polymer entropy will depend on the droplet shape. We compute the resulting surface free energy. Using parame- ters appropriate for polymers confined in microemulsions, we find that the polymer and bending surface energies are comparable for the lowest modes. Finally, we argue that chain self-avoidance will decrease the strength of the polymer contribution to the surface energy.
Parkinson’s Disease Patient-Derived Induced Pluripotent Stem Cells Free of Viral Reprogramming Factors

Induced pluripotent stem cells (iPSCs) derived from somatic cells of patients represent a powerful tool for biomedical research and may provide a source for replacement therapies. However, the use of viruses encoding the reprogramming factors represents a major limitation of the current technology since even low vector expression may alter the differentiation potential of the iPSCs or induce malignant transformation. Here, we show that fibroblasts from five patients with idiopathic Parkinson's disease can be efficiently reprogrammed and subsequently differentiated into dopaminergic neurons. Moreover, we derived hiPSCs free of reprogramming factors using Cre-recombinase excisable viruses. Factor-free hiPSCs maintain a pluripotent state and show a global gene expression profile, more closely related to hESCs than to hiPSCs carrying the transgenes. Our results indicate that residual transgene expression in virus-carrying hiPSCs can affect their molecular characteristics and that factor-free hiPSCs therefore represent a more suitable source of cells for modeling of human disease.
Radiative transport equation in rotated reference frames

A novel method for solving the linear radiative transport equation (RTE) in a three-dimensional homogeneous medium is proposed and illustrated with numerical examples. The method can be used with an arbitrary phase function with the constraint that it depends only on the angle between the angular variables and . This assumption corresponds to spherically symmetric (on average) random medium constituents. Boundary conditions are considered in the slab and half-space geometries. The approach developed in this paper is spectral. It allows for the expansion of the solution to the RTE in terms of analytical functions of angular and spatial variables to relatively high orders. The coefficients of this expansion must be computed numerically. However, the computational complexity of this task is much smaller than in the standard method of spherical harmonics. The solutions obtained are especially convenient for solving inverse problems associated with radiative transfer.
Decision support in a distributed environment

Traditional means of data processing, management information systems, and decision support systems cannot meet a new demand ushered in with the evolution of mini-micro computers. A modern computer end-user, especially a modern decision maker, needs a single pool of information that may be geographically dispersed. Therefore, a new combination of technologies is needed for coping with this new demand. The purpose of this paper is to develop a unified methodology for distributed-system design with distributed databases. The distributed systems designed under this unified methodology can satisfy geographical data independence in addition to logical and physical data independence in the traditional sense.
Foams Stabilized by In-Situ Surface-Activated Nanoparticles in Bulk and Porous Media

Foams for subsurface applications are traditionally stabilized by surfactants. The goal of this work is to study foam stabilization by nanoparticles—in particular, by in-situ surface-hydrophobization of hydrophilic nanoparticles. The interfacial properties of the nanoparticles were modulated by the attachment of short-chain surface modifiers (alkyl gallates) that render them partially hydrophobic, but still fully dispersible in water. First, static foams were generated with nanoparticles with varying concentrations of surface modifiers. The decay of foam height with time was measured, and half-lives were determined. Optical micrographs of foam stabilized by surface-modified nanoparticles (SMNPs) and surfactant were recorded. Second, aqueous foams were created insitu by coinjecting the SMNP solutions with nitrogen gas through a Berea sandstone core at a fixed quality. Pressure drop across the core was measured to estimate the achieved resistance factor. These pressure-drop results were then compared with those of a typical surfactant (alpha olefin sulfonate, alkyl polyglucoside) under similar conditions. Finally, oil-displacement experiments were conducted in Berea cores with surfactant and SMNP solutions as foaming agents (coinjection with nitrogen gas). A Bartsch shake test revealed the strong foaming tendency of SMNPs even with a very low initial surface-modifier concentration (0.05 wt%), whereas hydrophilic nanoparticles alone could not stabilize foam. The bubble texture of foam stabilized by SMNPs was finer than that with surfactants, indicating a stronger foam. As the degree of surface coating increased, the resistance factor of SMNP foam in a Berea core increased significantly. The corefloods in the sandstone cores with a reservoir crude oil showed that immiscible foams with SMNP solution can recover a significant amount of oil (20.6% of original oil in place) over waterfloods.
EFFECTS OF MONEY ON INTEREST RATES

Monetary authorities also tend to take for granted that an increase in the money stock lowers interest rates. From their vantage point, an increase in the money stock by way of an open-market purchase tends to lower market rates quickly, since purchasing securities raises their prices and lowers yields. Indeed, they rely on this relation in order to control rates. Accordingly, interest-rate movements are frequently viewed as indicators of recent monetary policy. Since the money/interest-rate relation is used in implementing monetary policy, it is particularly important that the monetary authorities know how the relation works. If the monetary authorities believed that they lower interest rates by increasing the money stock whereas this at first lowers and then later raises rates, the authorities' actions would work first toward and then against an interest-rate goal. Further, if interest rates are viewed as indicators of monetary policy, incorrect conclusions can easily follow if total effects are disregarded in favor of initial effects. The trouble with using interest rates as indicators of monetary policy is as follows: If income increases faster than money, interest rates will tend to rise, but if the income increase results from increases in the money stock, should monetary policy be called restrictive?
Real-Time Computation by n-Dimensional Iterative Arrays of Finite-State Machines

An n-dimensional iterative array of finite-state machines is formally introduced as a real-time tape acceptor. The computational characteristics of iterative arrays are illuminated by establishing several results concerning the sets of tapes that they recognize. Intercommunication between machines in an array is characterized by specifying a stencil for the array. The computing capability of the array is preserved even if its stencil is reduced to a simple form in which machines communicate only with their nearest neighbors. An increase of computing speed by a constant factor k is defined by encoding k-length blocks of the input tapes, which reduces the lengths of the tapes by 1/k; the time available for computation is correspondingly reduced since the computation must be real time. The computation speed of iterative arrays can be increased by any constant factor k. Two examples of one-dimensional arrays are provided. The first accepts the set of palindromes; the second accepts the set of all tapes of the form ττ (for any tape τ). The latter set of tapes is not a context-free language; therefore, the sets of tapes accepted by iterative arrays are not all contained in the class of context-free languages. Conversely, the class of context-free languages is not contained in the class of sets of tapes accepted by iterative arrays. The sets of tapes accepted by iterative arrays are closed under the operations: union, intersection, and complement; therefore, they form a Boolean algebra. They are not closed under the reflection or concatenation-product operations.
Enantioselective Carbonyl Propargylation by Iridium‐Catalyzed Transfer Hydrogenative Coupling of Alcohols and Propargyl Chlorides

It takes alkynes! Exposure of propargyl chlorides to primary benzylic alcohols in the presence of [Ir(cod){(R)-segphos}]OTf (cod = 1,5-cyclooctadiene, segphos = 5,5'-bis(diphenylphosphino)-4,4'-bi-1,3-benzodioxole, Tf = trifluoromethanesulfonyl) results in hydrogen exchange to give allenyliridium-aldehyde pairs that combine to form products of propargylation with high ee value (see scheme). The reaction can also be conducted using aldehydes.
Homodyning as universal detection

Homodyne tomography—i. e. homodyning while scanning the local oscillator phase—is now a well assessed method for “measuring” the quantum state. In this paper I will show how it can be used as a kind of universal detection, for measuring generic field operators, however at expense of some additional noise. The general class of field operators that can be measured in this way is presented, and includes also operators that are inaccessible to heterodyne detection. The noise from tomographical homodyning is compared to that from heterodyning, for those operators that can be measured in both ways. It turns out that for some operators homodyning is better than heterodyning when the mean photon number is sufficiently small. Finally, the robustness of the method to additive phase-insensitive noise is analyzed. It is shown that just half photon of thermal noise would spoil the measurement completely.
Work and Vocational Psychology: Theory, Research, and Applications

Work is integral to human functioning, and all psychologists need to understand the role of work in people's lives. Understanding factors influencing work choices and helping individuals effectively make career decisions is the focus of vocational psychologists. However, external changes, such as shifts in the economy and labor force, as well as initiatives within the field are challenging the assumptions within vocational psychology. This chapter reviews the empirical work since 1995 in four areas: (a) what factors influence career choices, (b) how people make career decisions, (c) how context influences career choices, and (d) effective interventions for help with the first three questions. The review focuses first on vocational psychology's rich tradition of theoretically driven research, and then discusses research in career development that crosses a number of theoretical approaches, and finally identifies the assumptions in the field and questions for future examination.
A concise synthesis of 2′-c-methylribonucleosides

Abstract 2′- C -Methylribonucleosides were synthesized in five steps from commercially available 1,3.5-tri- O -benzoyl-α- d -ribose with good overall yields.
Conventionally Sintered (Na0.5,K0.5)NbO3 with Barium Additions

The effect of Ba additions on sodium potassium niobate (NKN) ceramic bodies was investigated with regard to sintering behavior, densification, and electrical properties. Small additions of Ba retard grain growth and increase density. The approximate solubility limit of Ba is 1.5 mol%. During firing the loss of Na and K was very low. Both electrical phase transitions in NKN are lowered with Ba additions. The Ba-containing bodies show higher permittivity values than hot-pressed materials, while radial coupling and d33 were similar to or higher than those of the conventionally sintered pure materials.
Evolution of large Venusian volcanoes: Insights from coupled models of lithospheric flexure and magma reservoir pressurization

[1] The growth and evolution of large volcanic edifices on Venus should reflect interactions between local magma reservoir-induced stresses and broader-scale stresses resulting from flexure of the lithosphere beneath the edifice load. Here, we explore the relationship between magma movement in the lithosphere and the flexural stress state via static, gravitationally loaded, axisymmetric finite element models. We find that reservoirs situated in the lower (extensional) lithosphere fail at the bottom and are therefore not viable long-term conduits for upward magma transport. Furthermore, for high-stress conditions (e.g., large edifices or thin lithospheres), chambers in the lowermost lithosphere exceed the failure criterion even before pressurization and are therefore unstable. In contrast, magma chambers located in the upper (compressional) lithosphere fail at or somewhat above the reservoir midsection, promoting lateral sill injection; continued failure in this mode would tend to produce oblate magma chambers with zones of intrusion at their margins. Reservoirs near the flexural neutral plane require the greatest overpressure to reach failure, emplacing cone sheets that transition to sills further from the chamber. The out-of-plane orientation of principal extensional stresses in the flexed lower lithosphere predicts the presence of radial dikes that are likely the main conduits for any subsequent magma ascent from the mantle melt source region. Our results also explain how the evolving stress state in the lithosphere tends to redirect magma passage over time: magma ascending into the lithosphere beneath the edifice is diverted to lateral sills in the upper lithosphere, inhibiting summit eruptions and possibly shifting eruption locations to the lower flanks at and beyond the distal margins of an oblate chamber or sill complex. We apply these results to interpret the observed structure and tectonism of Sapas Mons, Venus, in terms of flexurally controlled intrusive processes.
Synthesis of helix 69 of Escherichia coli 23S rRNA containing its natural modified nucleosides, m3ψ and ψ

The synthesis of 3-methylpseudouridine (m3Ψ) phosphoramidite, 5‘-O-[benzhydryloxybis(trimethylsilyloxy)silyl]-2‘-O-[bis(2-acetoxyethoxy)methyl]-3-methylpseudouridine-3‘-(methyl-N,N-diisopropyl)phosphoramidite, is reported. Selective pivaloyloxymethyl protection of the Ψ N1 followed by methylation at N3 was used to generate the naturally occurring pseudouridine analogue. The m3Ψ phosphoramidite was used in combination with pseudouridine (Ψ) and standard base phosphoramidites to synthesize a 19-nucleotide RNA representing helix 69 of Escherichia coli 23S ribosomal RNA (rRNA) (residues 1906−1924), containing a single m3Ψ at position 1915 and two Ψ's at positions 1911 and 1917. Our synthesis of the fully modified helix 69 RNA demonstrates the ability to make milligram quantities of RNA that can be used for further high-resolution structure studies. Site-selective introduction of the methyl group at the N3 position of pseudouridine at position 1915 causes a slight increase in the thermodynamic stability of the...
Whisker Formation in Sn Coatings on Cu

In the microelectronics industry, Sn is often electroplated as a protective layer on Cu conductors. Pure Sn layers on Cu develop whiskers that can cause component failures and have even been implicated in the loss of several satellites. Alloying Sn with Pb suppresses whisker formation, but the push towards Pb-free processing will make this unacceptable in the future. To understand the driving forces and mechanisms of whisker formation on pure Sn, we are measuring the kinetics of stress evolution and intermetallic formation in Sn/Cu layers. By using thin films of Sn and Cu, we can monitor the stress evolution in real time using wafer-curvature based techniques. Preliminary results of stress evolution in vapor-deposited films are presented showing the evolution of tensile stress in the Cu layers and compressive stress in the Sn layers.
On a supercongruence conjecture of Rodriguez-Villegas

In examining the relationship between the number of points over $\mathbb{F}_p$ on certain Calabi-Yau manifolds and hypergeometric series which correspond to a particular period of the manifold, Rodriguez-Villegas identified numerically 22 possible supercongruences. We prove one of the outstanding supercongruence conjectures between a special value of a truncated generalized hypergeometric series and the $p$-th Fourier coefficient of a modular form.
Sherpa: a mission-independent data analysis application

The ever-increasing quality and complexity of astronomical data underscores the need for new and powerful data analysis applications. This need has led to the development of Sherpa, a modeling and fitting program in the CIAO software package that enables the analysis of multi-dimensional, multi-wavelength data. In this paper, we present an overview of Sherpa's features, which include: support for a wide variety of input and output data formats, including the new Model Descriptor List (MDL) format; a model language which permits the construction of arbitrarily complex model expressions, including ones representing instrument characteristics; a wide variety of fit statistics and methods of optimization, model comparison, and parameter estimation; multi-dimensional visualization, provided by ChIPS; and new interactive analysis capabilities provided by embedding the S-Lang interpreted scripting language. We conclude by showing example Sherpa analysis sessions.
A systematic revision of Edwardsiidae (Cnidaria, Anthozoa)

. Difficulties in addressing relationships among sea anemones are explored in the context of a revision of the family Edwardsiidae. This family has been important in discussions of relationships within Zoantharia (Cnidaria, Anthozoa), but has been poorly characterized. Genera within Edwardsiidae are characterized by a mosaic distribution of a few key characters whose actual distribution is not well understood; generalized and idealized morphology, rather than the actual distribution of characters, has been previously used to delimit genera. Microanatomy of muscles and the body wall, qualitative and quantitative information about muscle shape, and nematocyst size are combined with 18S rDNA sequences in a cladistic analysis. The results demonstrate that some traditional diagnostic features support groups different from those previously recognized. Character support is identified for several previously proposed taxa or clades, including the genus Edwardsiella and a clade containing Nematostella and Drillactis. Edwardsiidae and several of its genera are monophyletic; however, groups within the subfamily Edwardsiinae require revision and recircumscription. The genus Edwardsia is paraphyletic, and these data do not resolve Edwardsia species into monophyletic groups.
Ternary Threshold Logic

A new logical algebra, ternary threshold logic, is defined and developed. The system is shown to be capable of representing all three-valued functions, and two methods of synthesizing these functions from their truth tables are given. One of the methods produces a normal form that is analogous to the disjunctive normal form of Boolean algebra. A list of single-threshold-operator equivalents of certain normal forms is given. It is pointed out that magnetic film parametrons may be made to exhibit the logical properties of the operators of the system. Designs for ternary adder and comparator stages are given that could be constructed out of magnetic film parametrons.
Spanning trees and a conjecture of Kontsevich

Kontsevich conjectured that the number of zeros over the field q of a certain polyno- mial QG associated with the spanning trees of a graph G is a polynomial function of q. We show the connection between this conjecture, the Matrix-Tree Theorem, and orthogonal geometry. We verify the conjecture in certain cases, such as the complete graph, and discuss some modifications and extensions.
Space charge effect on betatron oscillations

The transverse motion of the beam at the AGS was studied by analyzing the coherent beam signals, digitized at a 10 ns interval, at various beam intensities. It was found that the coherent vertical tune shift of the centroid is consistent with the space charge model due to the image charge and current induced on the vacuum chamber wall. An enhanced linear coupling at a high intensity was also observed.
Enantiopure β-Hydroxy Morpholine Amides from Terminal Epoxides by Carbonylation at 1 atm

As a consequence of the recently developed hydrolytic kinetic resolution (HKR) reaction,[1] a wide variety of terminal epoxides are now readily accessible in enantiopure form. The synthetic utility of this family of chiral building blocks is certainly well established, yet it is likely that new and valuable reactivity remains to be uncovered. In that context, we have sought to develop practical methodology to effect elaboration of these compounds to more highly functionalized chiral intermediates. In 1999, we reported the [Co2(CO)8]catalyzed carbonylation of enantiomerically enriched epoxides under 40 atm of CO, to afford b-hydroxy methyl esters in good yield [Eq. (1)].[2] However, the relatively high CO pressure precludes its widespread application in laboratory and industrial settings, and the scope of nucleophiles that could be employed to trap the acylcobalt intermediate was in fact quite limited.[3] As a result, we became interested in devising complementary methodology that would afford general access to broadly useful b-hydroxy carbonyl derivatives under mild conditions.
Solar energy generation in three dimensions

We formulate, solve computationally and study experimentally the problem of collecting solar energy in three dimensions. We demonstrate that absorbers and reflectors can be combined in the absence of sun tracking to build three-dimensional photovoltaic (3DPV) structures that can generate measured energy densities (energy per base area, kWh/m2) higher by a factor of 2–20 than stationary flat PV panels for the structures considered here, compared to an increase by a factor of 1.3–1.8 for a flat panel with dual-axis sun tracking. The increased energy density is countered by a larger solar cell area per generated energy for 3DPV compared to flat panels (by a factor of 1.5–4 in our conditions), but accompanied by a vast range of improvements. 3DPV structures can mitigate some of the variability inherent to solar PV as they provide a more even source of solar energy generation at all latitudes: they can double the number of peak power generation hours and dramatically reduce the seasonal, latitude and weather variations of solar energy generation compared to a flat panel design. Self-supporting 3D shapes can create new schemes for PV installation and the increased energy density can facilitate the use of cheaper thin film materials in area-limited applications. Our findings suggest that harnessing solar energy in three dimensions can open new avenues towards Terawatt-scale generation.
Fluid limits for networks with bandwidth sharing and general document size distributions.

We consider a stochastic model of Internet congestion control, introduced by Massouli e and Roberts [18], that represents the randomly varying number of o ws in a network where bandwidth is shared amongst document transfers. In contrast to an earlier work by Kelly and Williams [12], the present paper allows interarrival times and document sizes to be generally distributed, rather than exponentially distributed. Furthermore, we allow a fairly general class of bandwidth sharing policies that includes the weighted -fair policies of Mo and Walrand [20], as well as certain other utility based scheduling policies. To describe the evolution of the system, measure valued processes are used to keep track of the residual document sizes of all o ws through the network. We propose a uid model (or formal functional law of large numbers approximation) associated with the stochastic o w level model. Under mild conditions, we show that the appropriately rescaled measure valued processes corresponding to a sequence of such models (with xed
Interpolation of near offsets using multiples and prediction-error filters

Reflection seismic data typically are undersampled. Missing near offsets can be interpolated in reflection seismic data with pseudoprimaries, generated by crosscorrelating multiples and primaries in incomplete recorded data. These pseudoprimary data can be generated at the missing near offsets but contain many artifacts, so it is undesirable simply to replace the missing data with the pseudoprimaries. A nonstationary prediction-error filter (PEF) can instead be estimated from the pseudoprimaries and used to interpolate missing data to produce an interpolated output that is superior to direct substitution of the pseudoprimaries into the missing offsets. This approach is applied successfully to 2D synthetic and field data. Limitations in conventional acquisition geometry limit this approach in 3D, which can be illustrated using a synthetic data set.
Diffusion maps, spectral clustering and reaction coordinates of dynamical systems

Abstract A central problem in data analysis is the low dimensional representation of high dimensional data and the concise description of its underlying geometry and density. In the analysis of large scale simulations of complex dynamical systems, where the notion of time evolution comes into play, important problems are the identification of slow variables and dynamically meaningful reaction coordinates that capture the long time evolution of the system. In this paper we provide a unifying view of these apparently different tasks, by considering a family of diffusion maps, defined as the embedding of complex (high dimensional) data onto a low dimensional Euclidean space, via the eigenvectors of suitably defined random walks defined on the given datasets. Assuming that the data is randomly sampled from an underlying general probability distribution p ( x ) = e − U ( x ) , we show that as the number of samples goes to infinity, the eigenvectors of each diffusion map converge to the eigenfunctions of a corresponding differential operator defined on the support of the probability distribution. Different normalizations of the Markov chain on the graph lead to different limiting differential operators. Specifically, the normalized graph Laplacian leads to a backward Fokker–Planck operator with an underlying potential of 2 U ( x ) , best suited for spectral clustering. A different anisotropic normalization of the random walk leads to the backward Fokker–Planck operator with the potential U ( x ) , best suited for the analysis of the long time asymptotics of high dimensional stochastic systems governed by a stochastic differential equation with the same potential U ( x ) . Finally, yet another normalization leads to the eigenfunctions of the Laplace–Beltrami (heat) operator on the manifold in which the data resides, best suited for the analysis of the geometry of the dataset regardless of its possibly non-uniform density.
The Dynamics of Nestedness Predicts the Evolution of Industrial Ecosystems

In economic systems, the mix of products that countries make or export has been shown to be a strong leading indicator of economic growth. Hence, methods to characterize and predict the structure of the network connecting countries to the products that they export are relevant for understanding the dynamics of economic development. Here we study the presence and absence of industries in international and domestic economies and show that these networks are significantly nested. This means that the less filled rows and columns of these networks' adjacency matrices tend to be subsets of the fuller rows and columns. Moreover, we show that their nestedness remains constant over time and that it is sustained by both, a bias for industries that deviate from the networks' nestedness to disappear, and a bias for the industries that are missing according to nestedness to appear. This makes the appearance and disappearance of individual industries in each location predictable. We interpret the high level of nestedness observed in these networks in the context of the neutral model of development introduced by Hidalgo and Hausmann (2009). We show that the model can reproduce the high level of nestedness observed in these networks only when we assume a high level of heterogeneity in the distribution of capabilities available in countries and required by products. In the context of the neutral model, this implies that the high level of nestedness observed in these economic networks emerges as a combination of both, the complementarity of inputs and heterogeneity in the number of capabilities available in countries and required by products. The stability of nestedness in industrial ecosystems, and the predictability implied by it, demonstrates the importance of the study of network properties in the evolution of economic networks.
Residential segregation in an all-integrationist world

This paper presents a variation of the Schelling [J. Math. Sociol. 1 (1971) 143; T.C. Schelling, Micromotives and Macrobehavior, Norton, New York, 1978] model to show that segregation emerges and persists even if every person in the society prefers to live in a half-black, half-white neighborhood. In contrast to Schelling’s inductive approach, we formulate neighborhood transition as a spatial game played on a lattice graph. The model is rigorously analyzed using techniques recently developed in stochastic evolutionary game theory. We derive our primary results mathematically and use agent-based simulations to explore the dynamics of segregation.
Grating-assisted coupling of optical fibers and photonic crystal waveguides.

We propose and analyze a highly efficient method of coupling light from optical fibers to two-dimensional photonic crystal waveguides. Efficient coupling is achieved by positioning of a tapered fiber parallel to the linear defect, where the photonic crystal’s cladding functions as a grating coupler and provides field confinement as well. Numerical simulations indicate that better than 90% transmission is possible with a full width at half-magnitude bandwidth of 12 nm. It is shown that one can increase the bandwidth by increasing the field overlap between the two waveguides.
Marginal Optimization of Observation Schedules

Introduction T Note presents a method for optimizing the selection of observations to be used in estimating the state of a linear dynamic system. Problems of this type arise in numerous applications, including space navigation' and calibration' and alignment of inertial navigation systems. In these problems, the associated loss function, which is to be minimized in selecting the observations, depends upon the propagation in time of the estimation errors. For example, in calibration and alignment of inertial navigation systems, the objective is to optimize the subsequent performance of the navigation system. Battin and Denham and Speyer derived differential improvement methods for the observation schedule, for the case that the quadratic loss function depends upon the estimation errors at a fixed time, and the objective is to define the optimum values of certain parameters, with respect to which the measurement sensitivity matrices are differentiable. A concise representation of generalized time-dependent quadratic loss functions was presented in a previous Note. In this Note, the equivalent representation is developed for a discrete-time system. This results in a recursion formula for defining the loss functions, and a computationally efficient algorithm for selecting observations in the order of maximum marginal improvement of the loss function.
The Coase conjecture with incomplete information on the monopolist's commitment

A key to the Coase conjecture is the monopolist’s inability to commit to a price, which leads consumers to believe that a high current price will be followed by low future prices. This paper studies the robustness of the Coase conjecture with respect to these beliefs of consumers. In particular, there is uncertainty over whether the monopolist is committed to a price (i.e. she may be a commitment type). Consequently, consumers are no longer certain that the price will change over time. I consider two kinds of commitment types. A behavioral commitment type charges an exogenously given price, while the rational commitment type optimally chooses a price. I show that the Coase conjecture is robust with regard to uncertainty over the monopolist’s commitment. When the probability of behavioral types is sufficiently small, as in the original Coase conjecture, the monopolist earns the competitive profit. When the probability of behavioral types is positive, unlike in the original Coase conjecture, there is positive delay. But the delay disappears as the probability approaches zero. When the commitment type is rational, unless the probability of the commitment type is sufficiently high, both normal and committed monopolists charge the competitive price, and thus there is no delay.
MAXIMUM UNION-FREE SUBFAMILIES

An old problem of Moser asks: what is the size of the largest union-free subfamily that one can guarantee in every family of m sets? A family of sets is called union-free if there are no three distinct sets in the family such that the union of two of the sets is equal to the third set. We show that every family of m sets contains a union-free subfamily of size at least \(\left\lfloor {\sqrt {4m + 1} } \right\rfloor - 1\) and that this bound is tight. This solves Moser’s problem and proves a conjecture of Erdős and Shelah from 1972.
Divided-pulse Amplification of Ultrashort Pulses

We demonstrate an approach to avoid nonlinear effects in amplification. The initial pulse is divided into a sequence of lower-energy identical pulses. The low-intensity pulses are amplified and recombined to create a final pulse.
Digital Signatures: A Business View

Abstract The technology to create secure digital signatures is proven and workable on PC-level hardware, as well as on mainframes. the issues currently restraining widespread use of digital signatures are primarily legal. This tutorial survey first identifies the functions a digital signature should ideally perform by tracing an example Internet-based electronic business transaction. After an overview of the technology that provides the required functionality, this article presents the current legal status of digital signature use, including a number of unresolved liability issues, and summarizes some precautions for digital signature use.
Conformal dimension and Gromov hyperbolic groups with 2-sphere boundary

Suppose G is a Gromov hyperbolic group, and @1G is quasisymmetrically homeomorphic to an Ahlfors Q–regular metric 2–sphere Z with Ahlfors regular conformal dimension Q. Then G acts discretely, cocompactly, and isometrically on H 3 .
AjaxScope: A Platform for Remotely Monitoring the Client-Side Behavior of Web 2.0 Applications

The rise of the software-as-a-service paradigm has led to the development of a new breed of sophisticated, interactive applications often called Web 2.0. While Web applications have become larger and more complex, Web application developers today have little visibility into the end-to-end behavior of their systems. This article presents AjaxScope, a dynamic instrumentation platform that enables cross-user monitoring and just-in-time control of Web application behavior on end-user desktops. AjaxScope is a proxy that performs on-the-fly parsing and instrumentation of JavaScript code as it is sent to users’ browsers. AjaxScope provides facilities for distributed and adaptive instrumentation in order to reduce the client-side overhead, while giving fine-grained visibility into the code-level behavior of Web applications. We present a variety of policies demonstrating the power of AjaxScope, ranging from simple error reporting and performance profiling to more complex memory leak detection and optimization analyses. We also apply our prototype to analyze the behavior of over 90 Web 2.0 applications and sites that use significant amounts of JavaScript.
Exploiting uniqueness in query optimization

Consider an SQL query that specifies duplicate elimination via a DISTINCT clause. Because duplicate elimination often requires an expensive sort of the query result, it is often worthwhile to identify situations where the DISTINCT clause is unnecessary, to avoid the sort altogether. We prove a necessary and sufficient condition for deciding if a query requires duplicate elimination. The condition exploits knowledge about keys, table constraints, and query predicates. Because the condition cannot always be tested efficiently, we offer a practical algorithm that tests a simpler, sufficient condition. We consider applications of this condition for various types of queries, and show that we can exploit this condition in both relational and nonrelational database systems.
Understanding the Failure of Health-care Exceptionalism in the Supreme Court's Obamacare Decision

On June 28, 2012, a mere century after the first presidential proposal for national health insurance, the Supreme Court issued a resounding victory for President Obama and for health-care reform generally, upholding the Patient Protection and Affordable Care Act against a serious constitutional challenge. Nevertheless, the Court also struck a potential blow to future health-care reform efforts in refusing to accept the solicitor general's argument that health care is a unique market with unique regulatory needs that justify special constitutional treatment. The failure of health-care exceptionalism in the Court's opinion might render future reform efforts more difficult than they would have been if the solicitor general's argument had carried the day. This commentary seeks to shed light on the Court's hesitation to recognize the uniqueness of health insurance and health care, noting that market-based exceptionalism in constitutional law has a long, dark history that the Court was understandably loath to repeat. Although the result of Chief Justice John Roberts' one-size-fits-all approach to constitutional analysis in this case is an odd holding that elides some genuine uniqueness of American health care, the alternative of health-care exceptionalism might have been much worse for our overall constitutional system.
Barred Preferential Arrangements

A preferential arrangement of a set is a total ordering of the elements of that set with ties allowed. A barred preferential arrangement is one in which the tied blocks of elements are ordered not only amongst themselves but also with respect to one or more bars. We present various combinatorial identities for $r_{m,\ell}$, the number of barred preferential arrangements of $\ell$ elements with $m$ bars, using both algebraic and combinatorial arguments. Our main result is an expression for $r_{m,\ell}$ as a linear combination of the $r_k$ ($= r_{0,k}$, the number of unbarred preferential arrangements of $k$ elements) for $\ell\le k\le\ell+m$. We also enumerate those arrangements in which the sections, into which the blocks are segregated by the bars, must be nonempty. We conclude with an expression of $r_\ell$ as an infinite series that is both convergent and asymptotic.
NOMAD: non-locking, stochastic multi-machine algorithm for asynchronous and decentralized matrix completion

We develop an efficient parallel distributed algorithm for matrix completion, named NOMAD (Non-locking, stOchastic Multi-machine algorithm for Asynchronous and Decentralized matrix completion). NOMAD is a decentralized algorithm with non-blocking communication between processors. One of the key features of NOMAD is that the ownership of a variable is asynchronously transferred between processors in a decentralized fashion. As a consequence it is a lock-free parallel algorithm. In spite of being asynchronous, the variable updates of NOMAD are serializable, that is, there is an equivalent update ordering in a serial implementation. NOMAD outperforms synchronous algorithms which require explicit bulk synchronization after every iteration: our extensive empirical evaluation shows that not only does our algorithm perform well in distributed setting on commodity hardware, but also outperforms state-of-the-art algorithms on a HPC cluster both in multi-core and distributed memory settings.
Total synthesis of guanacastepene a: a route to enantiomeric control.

The goal of the total synthesis of guanacastepene A served as a focus to bring together several chemical inquiries. One involved the synthesis of fused 5,7-hydrazulenones (see structure 20). Another issue had to do with the mechanistic intermediates in reductive cyclizations (see 17 to 18 and 19). The total synthesis required a mastery of an intramolecular Knoevenagel condensation of a β,γ-unsaturated ketone (see compound 41). Actually, cyclization was best accomplished when the terminal double bond of 41 was first converted to an epoxide. Further issues related to the stereochemistry at C5 and, rather surprisingly, the propensity for β-face acetoxylation at C13. Crystallographic verification of the assigned β-stereochemistry at C13 is provided. Finally, a route to optically active material is provided (see compound 20). A key element in this construction was an enantioselective addition of isopropenyl cuprate to 2-methylcyclopentenone (see compound 99).
A correlation between inclination and color in the classical kuiper belt

We have measured broadband optical BVR photometry of 24 classical and scattered Kuiper belt objects (KBOs), approximately doubling the published sample of colors for these classes of objects. We find a statistically significant correlation between object color and inclination in the classical Kuiper belt using our data. The color and inclination correlation increases in significance after the inclusion of additional data points culled from all published works. Apparently, this color and inclination correlation has not been more widely reported because the Plutinos show no such correlation and thus have been a major contaminant in previous samples. The color and inclination correlation excludes simple origins of color diversity, such as the presence of a coloring agent without regard to dynamical effects. Unfortunately, our current knowledge of the Kuiper belt precludes us from understanding whether the color and inclination trend is due to environmental factors, such as collisional resurfacing, or primordial population effects. A perihelion and color correlation is also evident, although this appears to be a spurious correlation induced by sampling bias, as perihelion and inclination are correlated in the observed sample of KBOs.
Stress‐Driven Morphological Instabilities in Rocks, Glass, and Ceramics

The purpose of this study is to further investigate the classical Gibbs analysis of the heterogeneous system "stressed crystal-melt." It is demonstrated that each equilibrium configuration is stable with respect to a special class of variations introduced by Gibbs. This basic result is compared with the opposite result on the universal morphological instability of phase interface separating a stressed crystal with its melt. Some plausible manifestations of the instabilities implied by the Gibbs model are qualitatively discussed.
Alcohols from ozonolysis products of unsaturated fatty esters

1-Nonanol and alkyl 9-hydroxynonanoates were more readily prepared by hydrogenation of the respective isolated aldehydes than by direct hydrogenation of products from reductive ozonolysis of oleate esters. Hydrogenation with nickel catalysts and aprotic solvents reduced the isolated aldehydes in good yield with a minimum of side reactions. Although the noble metal catalyst and hydroxylic solvent systems frequently used in similar reductions were also effective, they required a promoter that fortuitously catalyzed hydrolysis of acetals that formed during hydrogenation. Direct hydrogenation of the ozonolysis products resulted in side reactions and a mixture of products difficult to separate.