cssi/SciSciGPT-SciSciNet huggingface dataset:
Diversity of fault zone damage and trapping structures in the Parkfield section of the San Andreas Fault from comprehensive analysis of near fault seismograms

SUMMARY We perform comprehensive analyses of trapped waves and signals of damaged fault zone rocks associated with time delays of body waves along the Parkfield section of the San Andreas Fault (SAF). Waveforms generated by thousands of earthquakes and recorded by near fault stations in several permanent and temporary deployments are examined, with attention to the possible influence of a lithology contrast across the fault on signals of the low velocity damage zone. Clear candidate trapped waves are identified at only three stations, MMNB and two of the other near fault stations (FLIP and PIES) further to the NW. Clear candidate trapped waves are not seen at any of the near fault stations to the SE of MMNB. The locations of the events generating good candidate trapped waves at MMNB and the other two stations are not distributed broadly in space, but clustered in a small number of locations. Moreover, events that generate clear candidate trapped waves at one station do not typically generate trapped waves at the other two stations. These observations imply that the damage zone is highly variable along strike and that a coherent connected waveguide does not exist for distances along strike larger than at most 3–5 km (the distance between stations). Synthetic waveform fits for observed trapped waves at stations MMNB and FLIP indicate that the most likely parameters of the trapping structures at these locations are widths of about 150 m, depths of about 3 km, velocity reductions of 30–40 per cent, and Q values of 10–40. Synthetic calculations of trapped waves demonstrate that if there is a contrast of seismic velocity across the fault, the trapped waves are delayed relative to the S wave arrival. Trapped waves at station MMNB, and to a lesser extent also at stations FLIP and PIES in the NW section, show this characteristic. This suggests a lithology contrast in the top few km at these locations, in agreement with results from tomography and studies of head waves in the Parkfield area. At several mini across-fault arrays, where trapped waves are not observed, a low velocity damage zone is detected from the delay in the arrival time of body wave phases relative to a nearby off-fault station. The observed delay of the S wave is greater than the P wave delay, consistent with the existence of a damage zone with Poisson ratio of about 0.33. The observations of time delays without trapped waves indicate that parts of the damage zone are insufficiently coherent to generate trapped waves. A broader damage zone may exist in the region between the SAF and the South West Fracture Zone. The results highlight the diversity of damage structures along the ∼40 km of the SAF examined in this study, and imply that fault imaging based on data at single sites does not necessarily apply to a larger section.
Inflation Targeting as a Framework for Monetary Policy: A Cross-Country Analysis

This study makes use of a dynamic Taylor-type model to examine the conduct of monetary policy by central banks that profess to engage in inflation targeting. Previous research regarding inflation targeting and Taylor-type rules is reviewed and a dynamic Taylor-type model is developed. Tests for regime shifts upon the adoption of inflation targeting indicate a significant change in policy in each of the nations in the study for which sufficient data were available. Next, the central bank reaction functions were estimated. Results suggest that most of the central banks conducted a policy of inflation targeting by seeking to contain inflationary pressures rather than reacting to current inflation.
Sequential Importance Sampling and Resampling for Dynamic Portfolio Credit Risk

We provide a sequential Monte Carlo method for estimating rare-event probabilities in dynamic, intensity-based point process models of portfolio credit risk. The method is based on a change of measure and involves a resampling mechanism. We propose resampling weights that lead, under technical conditions, to a logarithmically efficient simulation estimator of the probability of large portfolio losses. A numerical analysis illustrates the features of the method and contrasts it with other rare-event schemes recently developed for portfolio credit risk, including an interacting particle scheme and an importance sampling scheme.
Traffic-Driven Spectrum Allocation in Heterogeneous Networks

Next generation cellular networks will be heterogeneous with dense deployment of small cells in order to deliver high data rate per unit area. Traffic variations are more pronounced in a small cell, which in turn lead to more dynamic interference to other cells. It is crucial to adapt radio resource management to traffic conditions in such a heterogeneous network (HetNet). This paper studies the optimization of spectrum allocation in HetNets on a relatively slow timescale based on average traffic and channel conditions (typically over seconds or minutes). Specifically, in a cluster with $n$ base transceiver stations (BTSs), the optimal partition of the spectrum into $2^n$ segments is determined, corresponding to all possible spectrum reuse patterns in the downlink. Each BTS's traffic is modeled using a queue with Poisson arrivals, the service rate of which is a linear function of the combined bandwidth of all assigned spectrum segments. With the system average packet sojourn time as the objective, a convex optimization problem is first formulated, where it is shown that the optimal allocation divides the spectrum into at most $n$ segments. A second, refined model is then proposed to address queue interactions due to interference, where the corresponding optimal allocation problem admits an efficient suboptimal solution. Both allocation schemes attain the entire throughput region of a given network. Simulation results show the two schemes perform similarly in the heavy-traffic regime, in which case they significantly outperform both the orthogonal allocation and the full-frequency-reuse allocation. The refined allocation shows the best performance under all traffic conditions.
PRECISION MASS DETERMINATION OF THE HIGGS BOSON AT PHOTON–PHOTON COLLIDERS

We demonstrate a measurement of the Higgs boson mass by the method of energy scanning at photon–photon colliders, using the high energy edge of the photon spectrum. With an integrated luminosity of 50 fb-1 it is possible to measure the standard model Higgs mass to within 110 MeV in photon–photon collisions for mh=100 GeV. As for the total width of the Higgs boson, the statistical error ΔΓh/Γh SM=0.06 is expected for mh=100 GeV, if both Γ(h→γγ) and are fixed at the predicted standard model value.
A REVISED AGE FOR UPPER SCORPIUS AND THE STAR FORMATION HISTORY AMONG THE F-TYPE MEMBERS OF THE SCORPIUS-CENTAURUS OB ASSOCIATION

We present an analysis of the ages and star formation history of the F-type stars in the Upper Scorpius (US), Upper Centaurus-Lupus (UCL), and Lower Centaurus-Crux (LCC) subgroups of Scorpius-Centaurus (Sco-Cen), the nearest OB association. Our parent sample is the kinematically selected Hipparcos sample of de Zeeuw et al., restricted to the 138 F-type members. We have obtained classification-resolution optical spectra and have also determined the spectroscopic accretion disk fraction. With Hipparcos and 2MASS photometry, we estimate the reddening and extinction for each star and place the candidate members on a theoretical H-R diagram. For each subgroup we construct empirical isochrones and compare to published evolutionary tracks. We find that (1) our empirical isochrones are consistent with the previously published age-rank of the Sco-Cen subgroups; (2) subgroups LCC and UCL appear to reach the main-sequence turn-on at spectral types ~F4 and ~F2, respectively. An analysis of the A-type stars shows US reaching the main sequence at about spectral type ~A3. (3) The median ages for the pre-main-sequence members of UCL and LCC are 16 Myr and 17 Myr, respectively, in agreement with previous studies, however we find that (4) Upper Sco is much older than previously thought. The luminosities of the F-type stars in US are typically a factor of ~2.5 less luminous than predicted for a 5 Myr old population for four sets of evolutionary tracks. We re-examine the evolutionary state and isochronal ages for the B-, A-, and G-type Upper Sco members, as well as the evolved M supergiant Antares, and estimate a revised mean age for Upper Sco of 11 ± 1 ± 2 Myr (statistical, systematic). Using radial velocities and Hipparcos parallaxes we calculate a lower limit on the kinematic expansion age for Upper Sco of >10.5 Myr (99% confidence). However, the data are statistically consistent with no expansion. We reevaluate the inferred masses for the known substellar companions in Upper Sco using the revised age and find that the inferred masses are typically ~20%-70% higher than the original estimates which had assumed a much younger age; specifically, we estimate the mass of 1RXS J1609-2105b to be 14+2 –3 M Jup, suggesting that it is a brown dwarf rather than a planet. Finally, we find the fraction of F-type stars exhibiting Hα emission and/or a K-band excess consistent with accretion to be 0/17 (<19%; 95% CL) in US at ~11 Myr, while UCL has 1/41 (2+5 –1%; 68% CL) accretors and LCC has 1/50 (2+4 –1%; 68% CL) accretors at ~16 Myr and ~17 Myr, respectively.
Reconsidering Baron and Kenny: Myths and Truths about Mediation Analysis

Baron and Kenny’s procedure for determining if an independent variable affects a dependent variable through some mediator is so well known that it is used by authors and requested by reviewers almost reflexively. Many research projects have been terminated early in a research program or later in the review process because the data did not conform to Baron and Kenny’s criteria, impeding theoretical development. While the technical literature has disputed some of Baron and Kenny’s tests, this literature has not diffused to practicing researchers. We present a nontechnical summary of the flaws in the Baron and Kenny logic, some of which have not been previously noted. We provide a decision tree and a step-by-step procedure for testing mediation, classifying its type, and interpreting the implications of findings for theory building and future research.
Is Europe Becoming the Most Dynamic Knowledge Economy in the World

The article discusses the condition and perspective of the European Union in the knowledge economy and the feasibility of the goal given by the European Council at the summits held in Lisbon (March 2000) and Barcelona (March 2002), that is, to increase European RD and intra-European distribution of resources and capabilities. A set of technological indicators is presented to show that Europe is still consistently behind when compared to Japan and the US, especially in R&D investment and the generation of innovations. A small convergence occurs in the diffusion of information and communication technologies (ICTs), the sector most directly linked to the concept of the ‘new economy’. In the field of knowledge collaboration, Europe takes opposing paths in the business and academic worlds. Within Europe, the level of investment in scientific and technological activities is so diverse across countries that it does not merge into a single continental innovation system.
An efficient partitioning oracle for bounded-treewidth graphs

Partitioning oracles were introduced by Hassidim et al. (FOCS 2009) as a generic tool for constant-time algorithms. For any e > 0, a partitioning oracle provides query access to a fixed partition of the input bounded-degree minor-free graph, in which every component has size poly(1/e), and the number of edges removed is at most en, where n is the number of vertices in the graph. However, the oracle of Hassidim et al. makes an exponential number of queries to the input graph to answer every query about the partition. In this paper, we construct an efficient partitioning oracle for graphs with constant treewidth. The oracle makes only O(poly(1/e)) queries to the input graph to answer each query about the partition. Examples of bounded-treewidth graph classes include k-outerplanar graphs for fixed k, series-parallel graphs, cactus graphs, and pseudoforests. Our oracle yields poly(1/e)-time property testing algorithms for membership in these classes of graphs. Another application of the oracle is a poly(1/e)-time algorithm that approximates the maximum matching size, the minimum vertex cover size, and the minimum dominating set size up to an additive en in graphs with bounded treewidth. Finally, the oracle can be used to test in poly(1/e) time whether the input boundedtreewidth graph is k-colorable or perfect.
Removal of U.S. Ethanol Domestic and Trade Distortions: Impact on U.S. and Brazilian Ethanol Markets

We analyze the impact of trade liberalization and removal of the federal tax credit in the United States on U.S. and Brazilian ethanol markets using a multi-market international ethanol model calibrated on 2005 market data and policies. The removal of trade distortions induces a 23.2 percent increase in the price of world ethanol on average between 2006 and 2015 relative to the baseline. The U.S. domestic ethanol price decreases by 14.1 percent, which results in a 7.5 percent decline in production and a 3.2 percent increase in consumption. The lower domestic price leads to a 2.5 percent rise in the share of fuel ethanol in gasoline consumption. U.S. net ethanol imports increase by 192.8 percent. Brazil responds to the higher world ethanol price by increasing its production by 8.8 percent on average. Total ethanol consumption in Brazil decreases by 3.2 percent and net exports increase by 61.9 percent relative to the baseline. The higher ethanol price leads to a 4.7 percent increase in the share of sugarcane used in ethanol production. The removal of trade distortions and 51Â¢ per gallon tax credit to refiners blending ethanol induces a 22.5 percent increase in the world ethanol price.
The Johnson---Lindenstrauss Lemma Almost Characterizes Hilbert Space, But Not Quite

Let X be a normed space that satisfies the Johnson–Lindenstrauss lemma (J–L lemma, in short) in the sense that for any integer n and any x 1,…,x n ∈X, there exists a linear mapping L:X→F, where F⊆X is a linear subspace of dimension O(log n), such that ‖x i −x j ‖≤‖L(x i )−L(x j )‖≤O(1)⋅‖x i −x j ‖ for all i,j∈{1,…,n}. We show that this implies that X is almost Euclidean in the following sense: Every n-dimensional subspace of X embeds into Hilbert space with distortion $2^{2^{O(\log^{*}n)}}$. On the other hand, we show that there exists a normed space Y which satisfies the J–L lemma, but for every n, there exists an n-dimensional subspace E n ⊆Y whose Euclidean distortion is at least 2Ω(α(n)), where α is the inverse Ackermann function.
A learning algorithm for multi-layer perceptrons with hard-limiting threshold units

We propose a novel learning algorithm to train networks with multilayer linear-threshold or hard-limiting units. The learning scheme is based on the standard backpropagation, but with "pseudo-gradient" descent, which uses the gradient of a sigmoid function as a heuristic hint in place of that of the hard-limiting function. A justification that the pseudo-gradient always points in the right down hill direction in error surface for networks with one hidden layer is provided. The advantages of such networks are that their internal representations in the hidden layers are clearly interpretable, and well-defined classification rules can be easily obtained, that calculations for classifications after training are very simple, and that they are easily implementable in hardware. Comparative experimental results on several benchmark problems using both the conventional backpropagation networks and our learning scheme for multilayer perceptrons are presented and analyzed. >
Random worlds and maximum entropy

Given a knowledge base KB containing first-order and statistical facts, we consider a principled method, called the random-worlds method, for computing a degree of belief that some formula Φ holds given KB. If we are reasoning about a world or system consisting of N individuals, then we can consider all possible worlds, or first-order models, with domain {1,..., N} that satisfy KB, and compute the fraction of them in which Φ is true. We define the degree of belief to be the asymptotic value of this fraction as N grows large. We show that when the vocabulary underlying Φ and KB uses constants and unary predicates only, we can naturally associate an entropy with each world. As N grows larger, there are many more worlds with higher entropy. Therefore, we can use a maximum-entropy computation to compute the degree of belief. This result is in a similar spirit to previous work in physics and artificial intelligence, but is far more general. Of equal interest to the result itself are the limitations on its scope. Most importantly, the restriction to unary predicates seems necessary. Although the random-worlds method makes sense in general, the connection to maximum entropy seems to disappear in the non-unary case. These observations suggest unexpected limitations to the applicability of maximum-entropy methods.
Extended Poisson Games and the Condorcet Jury Theorem

Abstract The Poisson model of games with population uncertainty is extended, by allowing that expected population sizes and players' utility functions may depend on an unknown state of the world. Such extended Poisson games are applied to prove a generalization of the Condorcet jury theorem. Journal of Economic Literature Classification Numbers: C72, D71.
Improved achievable rates for user cooperation and relay channels

In this paper a new achievable rate region for the user cooperation channel is derived which exceeds the best-known result for this channel. Since the user cooperation channel includes many other known channels as a special case, the new rate region provides improved achievable rates for these cases. The most notable example is that of the Gaussian relay channel, for which we present a new closed form inner bound higher than the only known result for many channel conditions.
Branching diffusions, superdiffusions and random media

Spatial branching processes became increasingly popular in the past decades, not only because of their obvious connection to biology, but also because superprocesses are intimately related to nonlinear partial differential equations. Another hot topic in today's research in probability theory is `random media', including the now classical problems on `Brownian motion among obstacles' and the more recent `random walks in random environment' and `catalytic branching' models. These notes aim to give a gentle introduction into some topics in spatial branching processes and superprocesses in deterministic environments (sections 2-6) and in random media (sections 7-11).
The Black–White Education Scaled Test-Score Gap in Grades K-7

We measure the black–white achievement gap from kindergarten through seventh grade on an interval scale created by tying each grade–test score combination to average eventual education. After correcting for various sources of test measurement error, some of which are unique to forward-looking scales, we find no racial component in the evolution of the achievement gap through the first eight years of schooling. Further, most, if not all, of the gap can be explained by socioeconomic differences. Our results suggest that the rising racial test gap in previous studies probably reflects excessive measurement error in testing in the early grades. [ABSTRACT FROM AUTHOR]
Return to the RNAi world: rethinking gene expression and evolution (Nobel Lecture).

It's wonderful to be here today, I would like to start with the most important part, by saying thank you. First of all, I want to thank Andy Fire for being such a tremendous colleague, friend, and collaborator going back over the years. Without Andy I definitely wouldn't be here today. I need to thank the University of Massachusetts for providing for my laboratory, for believing in me, and for giving me not only a place and money, but great colleagues with whom to pursue my research. Without UMass and the great environment provided for me there, I probably would not be here today. And, of course my family; I'm not going to spend time now thanking them individually, but they know how important they are.
Strongly Secure Communications Over the Two-Way Wiretap Channel

We consider the problem of secure communications over the two-way wiretap channel under a strong secrecy criterion. We improve existing results by developing an achievable region based on strategies that exploit both the interference at the eavesdropper's terminal and cooperation between legitimate users. We leverage the notion of channel resolvability for the multiple-access channel to analyze cooperative jamming and we show that the artificial noise created by cooperative jamming induces a source of common randomness that can be used for secret-key agreement. We illustrate the gain provided by this coding technique in the case of the Gaussian two-way wiretap channel, and we show significant improvements for some channel configurations.
Hyperfinite transversal theory

A measure theoretic version of a well-known P. Hall's theorem, about the existence of a system of distinct representatives of a finite family of finite sets, has been proved for the case of the Loeb space of an internal, uniformly distributed, hyperfinite counting space. We first prove Hall's theorem for Π 0 1 (κ) graphs after which we develop the version of discrete Transversal Theory. We then prove a new version of Hall's theorem in the case of Σ 0 1 (κ) monotone graphs and give an example of a Σ 0 1 graph which satisfies Hall's condition and which does not possess an internal a.e. matching
Two phase transitions for the contact process on small worlds

Abstract In our version of Watts and Strogatz’s small world model, space is a d -dimensional torus in which each individual has in addition exactly one long-range neighbor chosen at random from the grid. This modification is natural if one thinks of a town where an individual’s interactions at school, at work, or in social situations introduce long-range connections. However, this change dramatically alters the behavior of the contact process, producing two phase transitions. We establish this by relating the small world to an infinite “big world” graph where the contact process behavior is similar to the contact process on a tree. We then consider the contact process on a slightly modified small world model in order to show that its behavior is decidedly different from that of the contact process on a tree.
Acoustic convolver using multistrip beamwidth compressors

A degenerate nonlinear surface-wave convolver has been built from nonsymmetrical couplers working as beamwidth compressors to increase the acoustic power density and thus the bilinear merit factor. The measured results are compared with those of the classical LiNbO3 convolver, and the practical advantages of this new structure are pointed out. To demonstrate the device capability, the autocorrelation function of a linear f.m. pulse whose b.t. product was 120 has been performed.
Spectral-element simulations of wave propagation in porous media

We present a derivation of the equations describing wave propagation in porous media based upon an averaging technique which accommodates the transition from the microscopic to the macroscopic scale. We demonstrate that the governing macroscopic equations determined by Biot remain valid for media with gradients in porosity. In such media, the well-known expression for the change in porosity, or the change in the fluid content of the pores, acquires two extra terms involving the porosity gradient. One fundamental result of Biot's theory is the prediction of a second compressional wave, often referred to as 'type II' or 'Biot's slow compressional wave', in addition to the classical fast compressional and shear waves. We present a numerical implementation of the Biot equations for 2-D problems based upon the spectral-element method (SEM) that clearly illustrates the existence of these three types of waves as well as their interactions at discontinuities. As in the elastic and acoustic cases, poroelastic wave propagation based upon the SEM involves a diagonal mass matrix, which leads to explicit time integration schemes that are well suited to simulations on parallel computers. Effects associated with physical dispersion and attenuation and frequency-dependent viscous resistance are accommodated based upon a memory variable approach. We perform various benchmarks involving poroelastic wave propagation and acoustic–poroelastic and poroelastic–poroelastic discontinuities, and we discuss the boundary conditions used to deal with these discontinuities based upon domain decomposition. We show potential applications of the method related to wave propagation in compacted sediments, as one encounters in the petroleum industry, and to detect the seismic signature of buried landmines and unexploded ordnance.
Effects of combined stressing on the electrical properties of film and ceramic capacitors

Advanced power systems which generate, control and distribute electrical power to many large loads are a requirement for future space exploration missions. The development of high temperature insulating materials and power components constitute a key element in systems which are lightweight, efficient, and are capable of surviving the hostile space environment. In previous work, experiments were carried out to evaluate film and ceramic capacitors for potential use in high temperature applications. The effects of thermal stressing, in air and without electrical bias, on the electrical properties of the capacitors as a function of thermal aging up to 12 weeks were determined. In this work, the combined effects of thermal aging and electrical stresses on the properties of teflon film and ceramic power capacitors were examined. The ceramic capacitors were thermally aged for 35 weeks and the teflon capacitors for 15 weeks at 200/spl deg/C under full electrical bias and were characterized, on a weekly basis, in terms of their capacitance stability and electrical loss in the frequency range of 50 Hz to 100 kHz. DC leakage current measurements were also obtained. The results obtained represent the influence that short-term thermal aging and electrical bias, have on the electrical properties of the power capacitors characterized. >
Design and control of a kilo-amp DC/AC inverter for integrated starter-generator (ISG) applications

Design and control of a kilo-amp voltage source DC/AC inverter suitable for low voltage integrated starter-generator (ISG) operation is presented. Multiparallel MOSFETs are used to achieve extremely high current capability. Issues related to power module integration, filtering components and thermal management are discussed. A prototype with current capability up to 1500 amps is designed and built to validate the kilo-amp inverter. A sensorless control scheme based on indirect flux orientation (IFO) in ISG application is studied. Computer simulation and experimental results are presented for verification.
HII REGIONS IN ABSORPTION AT LOW FREQUENCIES

This paper reviews the information provided by the analysis of low radio frequency (v<100 MHz) observations of HII regions seen in absorption against the Galactic background radiation. We show how such observations can be used to constrain various physical parameters associated with the Galactic background and the HII regions. The technique is illustrated by analysis of 30.9 MHz observations of the W51 giant HII complex. The importance of obtaining observations made at more than one low frequency is emphasized.
Flashes in a star stream: Automated classification of astronomical transient events

An automated, rapid classification of transient events detected in the modern synoptic sky surveys is essential for their scientific utility and effective follow-up using scarce resources. This presents some unusual challenges: the data are sparse, heterogeneous and incomplete; evolving in time; and most of the relevant information comes not from the data stream itself, but from a variety of archival data and contextual information (spatial, temporal, and multi-wavelength). We are exploring a variety of novel techniques, mostly Bayesian, to respond to these challenges, using the ongoing CRTS sky survey as a testbed. The current surveys are already overwhelming our ability to effectively follow all of the potentially interesting events, and these challenges will grow by orders of magnitude over the next decade as the more ambitious sky surveys get under way. While we focus on an application in a specific domain (astrophysics), these challenges are more broadly relevant for event or anomaly detection and knowledge discovery in massive data streams.
DECIDING BETWEEN COMPETITION AND COLLUSION

We develop an approach to identify and test for bid rigging in procurement auctions. First, we introduce a general auction model with asymmetric bidders. Second, we study the problem of identie cation in our model. We state a set of conditions that are both necessary and sufe cient for a distribution of bids to be generated by a model with competitive bidding. Third, we discuss how to elicit a prior distribution over a e rm' s structural cost parameters from industry experts. Given this prior distri- bution, we use Bayes' s theorem to compare competitive and collusive models of industry equilibrium. Finally, we apply our methodology to a data set of bidding by construction e rms in the Midwest. The techniques we propose are not computationally demanding, use e exible functional forms, and can be programmed using most standard statistical packages.
A five-leg inverter for driving a traction motor and a compressor motor

This paper presents an integrated inverter for speed control of a traction motor and a compressor motor to reduce the compressor drive cost in electric vehicle/hybrid electric vehicle applications. The inverter comprises five phase-legs; three of which are for control of a three-phase traction motor and the remaining two for a two-phase compressor motor with three terminals. The common terminal of the two-phase motor is tied to the neutral point of the three-phase traction motor to eliminate the requirement of a third phase leg. Further component reduction is made possible by sharing the switching devices, dc bus filter capacitors, gate drive power supplies, and control circuit. Simulation and experimental results are included to verify that speed control of the two motors is independent from each other
Terahertz-optical mixing in undoped and doped GaAs quantum wells: From excitonic to electronic intersubband transitions

The mixing of near-infrared and terahertz (THz) beams has been observed in $n$-doped GaAs quantum wells (QWs) and is shown to be quite different from that in undoped QWs. The resonant behavior of the sidebands demonstrates that mixing in doped QWs is primarily sensitive to electronic intersubband transitions while that in undoped QWs is due to excitonic intersubband transitions. These results demonstrate that THz-optical mixing can be used to probe the collective dynamics of a driven electron gas.
Q-Ball of Inferior Fronto-Occipital Fasciculus and Beyond

The inferior fronto-occipital fasciculus (IFOF) is historically described as the longest associative bundle in the human brain and it connects various parts of the occipital cortex, temporo-basal area and the superior parietal lobule to the frontal lobe through the external/extreme capsule complex. The exact functional role and the detailed anatomical definition of the IFOF are still under debate within the scientific community. In this study we present a fiber tracking dissection of the right and left IFOF by using a q-ball residual-bootstrap reconstruction of High-Angular Resolution Diffusion Imaging (HARDI) data sets in 20 healthy subjects. By defining a single seed region of interest on the coronal fractional anisotropy (FA) color map of each subject, we investigated all the pathways connecting the parietal, occipital and posterior temporal cortices to the frontal lobe through the external/extreme capsule. In line with recent post-mortem dissection studies we found more extended anterior-posterior association connections than the "classical" fronto-occipital representation of the IFOF. In particular the pathways we evidenced showed: a) diffuse projections in the frontal lobe, b) fronto-parietal lobes connections trough the external capsule in almost all the subjects and c) widespread connections in the posterior regions. Our study represents the first consistent in vivo demonstration across a large group of individuals of these novel anterior and posterior terminations of the IFOF detailed described only by post-mortem anatomical dissection. Furthermore our work establishes the feasibility of consistent in vivo mapping of this architecture with independent in vivo methodologies. In conclusion q-ball tractography dissection supports a more complex definition of IFOF, which includes several subcomponents likely underlying specific function.
Robust stabilization of tone reproduction curves for the xerographic printing process

The problem of stabilizing a single color tone reproduction curve of a xerographic printing engine is considered. This problem is critical to ensure high-fidelity color printing. The control system uses a small number of actuators and a small number of measurements to stabilize the potentially high-dimensional tone reproduction curve. The goal is to minimize the overall least squares deviation of the tone reproduction curve from the ideal nominal one in the face of disturbances like material changes, temperature, humidity, and uncertainty in the system description. The control design consists of the steps of (1) determining a robust optimally performing static controller and (2) realizing the controller that utilizes only past measurements. Numerical simulations and experiments validate the efficacy of the controller.
COMPARISON OF SPECTRAL SLOPES OF MAGNETOHYDRODYNAMIC AND HYDRODYNAMIC TURBULENCE AND MEASUREMENTS OF ALIGNMENT EFFECTS

We performed a series of high-resolution (up to 1024 3 ) direct numerical simulations of hydro and MHD turbulence. Our simulations correspond to the ”strong” MHD turbulence regime that cannot be treated perturbatively. We found that for simulations with normal viscosity the slopes for energy spectra of MHD are similar to ones in hydro, although slightly more shallower. However, for simulations with hyper viscosity the slopes were very different, for instance, the slopes for hydro simulations showed pronounced and well-defined bottleneck effect, while the MHD slopes were relatively much less affected. We believe that this is indicative of MHD strong turbulence being less local than Kolmogorov turbulence. This calls for revision of MHD strong turbulence models that assume local “as-in-hydro case” cascading. Non-locality of MHD turbulence casts doubt on numerical determination of the slopes with currently available (512 3 –1024 3 ) numerical resolutions, including simulations with normal viscosity. We also measure various so-called alignment effects and discuss their influence on the turbulent cascade. Subject headings: MHD – turbulence – ISM: kinematics and dynamics
Broken Down by Race and Gender? Sociological Explanations of New Sources of Earnings Inequality

Group gaps research risks irrelevance because new forms of earnings inequality are increasing inequality within groups. This review attempts to stimulate more broad-ranging research on earnings inequality beyond the study of average gender and racial gaps. After reviewing some of the problems with research on average group gaps, I provide a brief review of more recent attempts to transcend traditional group gaps research, and I point to some areas where there is still substantive neglect. The review ends with suggestions for ways to correct these problems and for inequality researchers to reconnect with a commitment to more comprehensive theoretical models that interrogate multiple sources of inequality.
Dimension theory and parameterized normalization for D-semianalytic sets over non-Archimedean fields

We develop a dimension theory for D-semianalytic sets over an arbitrary non-Archimedean complete field. Our main results are the equivalence of several notions of dimension and a theorem on additivity of dimensions of projections and fibers in characteristic 0. We also prove a parameterized version of normalization for D-semianalytic
Reprogramming LCLs to iPSCs Results in Recovery of Donor-Specific Gene Expression Signature

Renewable in vitro cell cultures, such as lymphoblastoid cell lines (LCLs), have facilitated studies that contributed to our understanding of genetic influence on human traits. However, the degree to which cell lines faithfully maintain differences in donor-specific phenotypes is still debated. We have previously reported that standard cell line maintenance practice results in a loss of donor-specific gene expression signatures in LCLs. An alternative to the LCL model is the induced pluripotent stem cell (iPSC) system, which carries the potential to model tissue-specific physiology through the use of differentiation protocols. Still, existing LCL banks represent an important source of starting material for iPSC generation, and it is possible that the disruptions in gene regulation associated with long-term LCL maintenance could persist through the reprogramming process. To address this concern, we studied the effect of reprogramming mature LCL cultures from six unrelated donors to iPSCs on the ensuing gene expression patterns within and between individuals. We show that the reprogramming process results in a recovery of donor-specific gene regulatory signatures, increasing the number of genes with a detectable donor effect by an order of magnitude. The proportion of variation in gene expression statistically attributed to donor increases from 6.9% in LCLs to 24.5% in iPSCs (P < 10-15). Since environmental contributions are unlikely to be a source of individual variation in our system of highly passaged cultured cell lines, our observations suggest that the effect of genotype on gene regulation is more pronounced in iPSCs than in LCLs. Our findings indicate that iPSCs can be a powerful model system for studies of phenotypic variation across individuals in general, and the genetic association with variation in gene regulation in particular. We further conclude that LCLs are an appropriate starting material for iPSC generation.
FIR modeling using log-bispectra: weighted least-squares algorithms and performance analysis

Identification of non-minimum-phase systems with finite impulse response (FIR) is addressed in the bispectrum domain. A bispectrum-based phase retrieval algorithm is modified to handle the phase wrapping problem and is extended to log-magnitude reconstruction. Both linear-equation-based estimators (the phase and the log-magnitude) are then combined to form an integrated, nonparametric system identification method. Weighted forms of the estimators that are asymptotically minimum-variance in the class of weighted least-squares estimators are developed. Asymptotic variance expressions are derived for both the weighted and the unweighted forms. Theory and simulations illustrate that these approaches can identify non-minimum-phase moving-average models, using output data that may be corrupted by additive Gaussian noise of unknown covariance. Due to their nonparametric nature, the proposed algorithms outperform existing linear equation cumulant-based modeling methods in the case of model order mismatch. >
The contractarian constitutional political economy of James Buchanan

Constitutional political economy was the field in which James Buchanan devoted the most effort and to which he made the largest contribution. Although his finely grained arguments cannot be easily summarized, the main developments and central line of reasoning can be covered in a single paper, because his research relied upon a single framework, which continually reappears and is further developed as his thinking matured. The goal of this paper is to analyze how his ideas emerged and were used to develop a very rich constitutional political economy.
Evolution of the vinylogous Mannich reaction as a key construction for alkaloid synthesis.

The vinylogous Mannich reaction is rapidly emerging as an important process for the construction of derivatives of δ-aminocarbonyl compounds. Because the iminium and dienol components employed in this addition may be either acyclic or cyclic, a wide variety of adducts may be quickly assembled. These intermediates may then in turn be converted into a broad array of alkaloids and substituted nitrogen heterocycles. We have developed a number of variations of this reaction and have applied some of them to the concise syntheses of a number of structurally diverse and complex alkaloid natural products. Many of these results are presented in a historical context in this Account.
Optimal Monetary Policy and Downward Nominal Wage Rigidity in Frictional Labor Markets

Abstract This paper studies the optimal long-run inflation rate in a labor search and matching framework in the presence of downward nominal wage rigidity. Optimal monetary policy features positive inflation in the long run; the optimal annual long-run inflation rate for the U.S. economy is slightly below 1 percent with a money demand motive and around 2 percent otherwise. Positive inflation facilitates real wage adjustments and hence it eases job creation and prevents excessive increase in unemployment following adverse productivity shocks. The findings of the paper can also be related to standard Ramsey theory of “wedge smoothing”; with positive inflation under sticky prices, the size and the volatility of the intertemporal wedge are significantly reduced.
Evaluating the Impacts of Local Economic Development Policies on Local Economic Outcomes: What has been done and what is doable?

This paper argues that more rigorous evaluations of local economic development policies are feasible. Programs that aid selected small firms can be rigorously evaluated using an experimental approach, without excluding firms from assistance, by randomly assigning some firms to receive more intense marketing efforts by the program. Programs that aid distressed local...
The Finite State Projection Approach for the Analysis of Stochastic Noise in Gene Networks

In order to capture important subcellular dynamics, researchers in computational biology have begun to turn to mesoscopic models in which molecular interactions at the gene level behave as discrete stochastic events. While the trajectories of such models cannot be described with deterministic expressions, the probability distributions of these trajectories can be described by the set of linear ordinary differential equations known as the chemical master equation (CME). Until recently, it has been believed that the CME could only be solved analytically in the most trivial of problems, and the CME has been analyzed almost exclusively with kinetic Monte Carlo (KMC) algorithms. However, concepts from linear systems theory have enabled the finite state projection (FSP) approach and have significantly enhanced our ability to solve the CME without resorting to KMC simulations. In this paper, we review the FSP approach and introduce a variety of systems-theory-based modifications and enhancements to the FSP algorithm. Notions such as observability, controllability, and minimal realizations enable large reductions and increase efficiency with little to no loss in accuracy. Model reduction techniques based upon linear perturbation theory allow for the systematic projection of multiple time-scale dynamics onto a slowly varying manifold of much smaller dimension. We also present a powerful new reduction approach, in which we perform computations on a small subset of configuration grid points and then interpolate to find the distribution on the full set. The power of the FSP and its various reduction approaches is illustrated on few important models of genetic regulatory networks.
The ecology of organizational demography: managerial tenure distributions and organizational competition

This paper argues that turnover processes in top management teams create inter-organizational interdependencies. I argue that managerial capabilities are shaped by their experiences in a given competitive context; differences in managerial tenure therefore lead to differences in managerial capabilities. A comparison of the tenure distribution of a top management team with those of its competitors therefore captures the extent to which a firm relies on managerial capabilities similar to those of its competitors. Overlap in managerial capabilities will lead to greater competition for resources, since managers shape a firm's pattern of resource utilization. I hypothesize that organizational growth rates will decline to the extent that competitors are crowded around a firm's location in the tenure distribution. Analyses of growth in viewership among commercial television stations support this claim. Copyright 1999 by Oxford University Press.
Patents, trade secrets and the correlation among R&D projects

Abstract In patent race models, firms' noncooperatively chosen research projects typically display too much correlation. But when there are multiple intellectual property rights protection instruments, we find that the paths chosen in an R&D race can move towards the social optimum.
A CONVENIENT ONE-POT SYNTHESIS OF 13-PERFLUOROALKYLATED RETINOIDS

ABSTRACT 11,12-Dehydro-13-perfluoroalkylretinoate esters (and retinonitriles) have been prepared in one step assembly of the retinoid skeleton via the “16 + 4” strategy for retinoid synthesis.
A mathematical theory of stochastic microlensing. II. Random images, shear, and the Kac-Rice formula

Continuing our development of a mathematical theory of stochastic microlensing, we study the random shear and expected number of random lensed images of different types. In particular, we characterize the first three leading terms in the asymptotic expression of the joint probability density function (pdf) of the random shear tensor due to point masses in the limit of an infinite number of stars. Up to this order, the pdf depends on the magnitude of the shear tensor, the optical depth, and the mean number of stars through a combination of radial position and the star’s mass. As a consequence, the pdf’s of the shear components are seen to converge, in the limit of an infinite number of stars, to shifted Cauchy distributions, which shows that the shear components have heavy tails in that limit. The asymptotic pdf of the shear magnitude in the limit of an infinite number of stars is also presented. All the results on the random microlensing shear are given for a general point in the lens plane. Extending to the general random distributions (not necessarily uniform) of the lenses, we employ the Kac–Rice formula and Morse theory to deduce general formulas for the expected total number of images and the expected number of saddle images. We further generalize these results by considering random sources defined on a countable compact covering of the light source plane. This is done to introduce the notion of global expected number of positive parity images due to a general lensing map. Applying the result to microlensing, we calculate the asymptotic global expected number of minimum images in the limit of an infinite number of stars, where the stars are uniformly distributed. This global expectation is bounded, while the global expected number of images and the global expected number of saddle images diverge as the order of the number of stars.