cssi/SciSciGPT-SciSciNet huggingface dataset:
The dynamics of Rayleigh–Taylor stable and unstable contact discontinuities with anisotropic thermal conduction

We study the effects of anisotropic thermal conduction along magnetic field lines on an accelerated contact discontinuity in a weakly collisional plasma. We first perform a linear stability analysis similar to that used to derive the Rayleigh–Taylor instability (RTI) dispersion relation. We find that anisotropic conduction is only important for compressible modes, as modes in the Boussinesq limit are isothermal. Modes grow faster in the presence of anisotropic conduction, but growth rates do not change by more than a factor of the order of unity. We next run fully non-linear numerical simulations of a contact discontinuity with anisotropic conduction. The non-linear evolution can be thought of as a superposition of three physical effects: temperature diffusion due to vertical conduction, the RTI and the heat flux driven buoyancy instability (HBI). We find that the presence of the magnetothermal instability (MTI) does not significantly affect the dynamics. In simulations with RTI-stable contact discontinuities, the temperature discontinuity spreads due to vertical heat conduction. This occurs even for initially horizontal magnetic fields due to the initial vertical velocity perturbation and numerical mixing across the interface. The HBI slows this temperature diffusion by reorienting initially vertical magnetic field lines to a more horizontal geometry. In simulations with RTI-unstable contact discontinuities, the dynamics are initially governed by temperature diffusion, but the RTI becomes increasingly important at late times. We discuss the possible application of these results to supernova remnants, solar prominences and cold fronts in galaxy clusters.
Compact Electro-Optic Modulator on Silicon-on-Insulator Substrates using Cavities with Ultra-Small Modal Volumes

We experimentally demonstrate an electro-optic modulator using a high-index-contrast silicon Fabry-Perot resonator. This compact high-speed device is a 1-D integrated cavity, only 4.5 lambda/n in length with an embedded p-i-n junction on a silicon-on-insulator platform
Superhalogens as Building Blocks of Halogen‐Free Electrolytes in Lithium‐Ion Batteries

Most electrolytes currently used in Li-ion batteries contain halogens, which are toxic. In the search for halogen-free electrolytes, we studied the electronic structure of the current electrolytes using first-principles theory. The results showed that all current electrolytes are based on superhalogens, i.e., the vertical electron detachment energies of the moieties that make up the negative ions are larger than those of any halogen atom. Realizing that several superhalogens exist that do not contain a single halogen atom, we studied their potential as effective electrolytes by calculating not only the energy needed to remove a Li+ ion but also their affinity towards H2O. Several halogen-free electrolytes are identified among which Li(CB11H12) is shown to have the greatest potential.
Water soluble triazolopyridiniums as tunable blue light emitters

Two [1,2,3]triazolo[1,5-a]pyridinium salts have been prepared via a novel Cu(II)-mediated oxidative cyclization reaction. Both water soluble compounds exhibit broad-range fluorescence emission with huge Stokes shifts as well as color tunability.
Albumin polymorphism in the feral donkey of Death Valley National Monument, California.

Summary Evidence is presented for the occurrence of a second allele in the albumin system of the donkey (Equus asinus). Samples were collected from 127 feral donkeys in four locations within the Panamint Mountains of Death Valley National Monument, California. A common phenotype, electrophoretically characterized by a single band, was recorded from all four locations. A rare, double-band phenotype was recorded from two locations.
Relative Cohort Size: Source of a Unifying Theory of Global Fertility Transition?

This paper examines the feasibility of the relative cohort size (RCS) theory and the supply-demand framework in determining fertility patterns in both developed and developing countries. Data suggest that the RCS mechanism applies not just in developed countries but also within the supply-demand framework. The evidence shows that one thing countries had in common at the point of demographic transition was increasing relative cohort size. Thus RCS can be thought of as the mechanism that forestalls excessive rates of population change. It reduces fertility when previously high rates in combination with low mortality rates have caused relative cohort size to increase. On the other hand it increases fertility when previously low rates have caused relative cohort size to decrease. Furthermore the mechanism appears to have been operating not just in currently developed post-transition economies but during both recent and historic fertility transitions.
Belted and unbelted driver accident involvement rates compared

Abstract Although it has been recognized for some time that drivers who wear safety belts differ in various ways (for example, risk-taking) from those who do not, such effects have not been estimated quantitatively. In this study, quantitative estimates are obtained for the ratio of involvement rates of unbelted drivers compared to involvement rates of belted drivers in seven types of traffic incidents (crashes or violations). Three of these use Fatal Accident Reporting System (FARS) data, and four use previously reported observational data. For all seven cases studied, unbelted driver involvement rates were 28% to 86% higher than those for belted drivers—the average being 53%. Such quantitative information is necessary for calculations of benefits to be expected from increases in safety belt use.
Obstacles and Opportunities to Improve Antiretroviral Regimen Access in Low-Income Countries

Increasing evidence suggests that dramatically increasing access to effective and well-tolerated antiretroviral medications is key to reversing the HIV pandemic. Currently used first-line therapies in developing countries have multiple toxicities that cause significant morbidity and mortality. New World Health Organization HIV treatment guidelines support earlier treatment initiation and the use of less toxic first-line therapies. Adoption of these guidelines requires political and financial commitment from multiple stakeholders including country governments and donors. This review summarizes the major adverse effects associated with commonly used ARV regimens in low-income countries and also analyzes some of the barriers and potential solutions that affect the ability of low-income countries to implement the new World Health Organization guidelines.
THE "NEW ECONOMY" AND EFFICIENCY IN FOOD MARKET SYSTEM: A COMPLEMENT OR A BATTLEGROUND BETWEEN ECONOMIC CLASSES?

Abstract Rapid developments in E-commerce can bring efficiency in the food market system by cutting transaction costs. However, it can also bring a battleground between developed and developing countries and also within developed countries because the New Economy emphasizes knowledge-based labor practices and low-skilled workers of trading nations compete for a shrinking need for their services. An Input–Output model is used to examine the effects on high-skilled and low-skilled worker demand, particularly in food and agriculture. The food and agricultural industries are significant employers of low-skilled labor. Food and agricultural trade has reduced low-skilled labor demand in the United States.
When Is the Government Spending Multiplier Large

We argue that the government-spending multiplier can be much larger than one when the zero lower bound on the nominal interest rate binds. The larger the fraction of government spending that occurs while the nominal interest rate is zero, the larger the value of the multiplier. After providing intuition for these results, we investigate the size of the multiplier in a dynamic, stochastic, general equilibrium model. In this model the multiplier effect is substantially larger than one when the zero bound binds. Our model is consistent with the behavior of key macro aggregates during the recent financial crisis.
Locally testable codes and cayley graphs

We give two new characterizations of ( 2-linear, smooth) locally testable error-correcting codes in terms of Cayley graphs over Fh2: A locally testable code is equivalent to a Cayley graph over h2 whose set of generators is significantly larger than h and has no short linear dependencies, bbut yields a shortest-path metric that embeds into l with constant distortion. This extends and gives a converse to a result of Khot and Naor (2006), which showed that codes with large dual distance imply Cayley graphs that have no low-distortion embeddings into l . A locally testable code is equivalent to a Cayley graph over Fh2 that has significantly more than h eigenvalues near 1, which have no short linear dependencies among them and which "explain" all of the large eigenvalues. This extends and gives a converse to a recent construction of Barak et al. (2012), which showed that locally testable codes imply Cayley graphs that are small-set expanders but have many large eigenvalues.
PRICE DISPERSION IN THE SMALL AND IN THE LARGE: EVIDENCE FROM AN INTERNET PRICE COMPARISON SITE

This paper examines four million daily price observations for more than 1,000 consumer electronics products on the price comparison site http://Shopper.com. We find little support for the notion that prices on the Internet are converging to the ‘law of one price.’ In addition, observed levels of price dispersion vary systematically with the number of firms listing prices. The difference between the two lowest prices (the ‘gap’) averages 23 per cent when two firms list prices, and falls to 3.5 per cent in markets where 17 firms list prices. These empirical results are an implication of a general ‘clearinghouse’ model of equilibrium price dispersion.
Cofree coalgebras over operads

Abstract This paper explicitly constructs cofree coalgebras over operads in the category of DG-modules. Special cases are also considered in which the general expression simplifies (such as the pointed, irreducible case).
Information, Misallocation, and Aggregate Productivity

We propose a theory linking imperfect information to resource misallocation and hence to aggregate productivity and output. In our setup, firms learn from both private sources and imperfectly informative stock market prices. We devise a novel calibration strategy that uses a combination of firm-level production and stock market data to pin down the information structure in the economy. Applying this methodology to data from the US, China, and India reveals substantial losses in productivity and output due to informational frictions - even when only one factor, namely capital, is subject to the friction. Our estimates for these losses range from 5-19% for productivity and 8-28% for output in China and India, and are smaller, though still significant, in the US. Losses are substantially higher when labor decisions are also made under imperfect information. Private learning plays a significant role in mitigating uncertainty and improving aggregate outcomes; learning from financial markets contributes little, even in the US.
State assignment for low power dissipation

We address the problem of reducing the power dissipated by synchronous sequential circuits. We target the reduction of the average switching activity of the input and output state variables by minimizing the number of bit changes during state transitions. Using a probabilistic description of the finite state machines, we propose a state assignment algorithm that minimizes the Boolean distance between the codes of the states with high transition probability. We formulate a general theoretic framework for the solution of the state assignment problem, and propose different algorithms trading off computational effort for quality. We then generalize our model to take into account the estimated area of a multilevel implementation during state assignment, in order to obtain final circuits where the total power dissipation is minimized. A heuristic algorithm has been implemented and applied to standard benchmarks, resulting in a 16% average reduction in switching activity. >
Building a Large Knowledge Base for a Natural Language System

A sophisticated natural language system requires a large knowledge base. A methodology is described for constructing one in a principled way. Facts are selected for the knowledge base by determining what facts are linguistically presupposed by a text in the domain of interest. The facts are sorted into clusters, and within each cluster they are organized according to their logical dependencies. Finally, the facts are encoded as predicate calculus axioms.
GLUINO CONTRIBUTION TO THE 3-LOOP QUARK MASS ANOMALOUS DIMENSION IN THE MINIMAL SUPERSYMMETRIC STANDARD MODEL

We deduce the gluino contribution to the three-loop QCD quark mass anomalous dimension function within the minimal supersymmetric Standard Model (MSSM) from its standard QCD expression. This work is a continuation of the program of computation of MSSM renormalization group functions.
TEMPORAL RELATIONS: REFERENCE OR DISCOURSE COHERENCE?

The temporal relations that hold between events described by successive utterances are often left implicit or underspecified. We address the role of two phenomena with respect to the recovery of these relations: (1) the referential properties of tense, and (2) the role of temporal constraints imposed by coherence relations. We account for several facets of the identification of temporal relations through an integration of these.
On inertial-range scaling laws

Inertial-range scaling laws for two- and three-dimensional turbulence are re-examined within a unified framework. A new correction to Kolmogorov`s k{sup {minus}5/3} scaling is derived for the energy inertial range. A related modification is found to Kraichnan`s logarithmically corrected two-dimensional enstrophy cascade law that removes its unexpected divergence at the injection wavenumber. The significance of these corrections is illustrated with steady-state energy spectra from recent high-resolution closure computations. The results also underscore the asymptotic nature of inertial-range scaling laws. Implications for conventional numerical simulations are discussed.
Nonlinear response of HTSC thin film microwave resonators in an applied DC magnetic field

The non-linear microwave surface impedance, Z/sub s/=R/sub s/+iX/sub s/, of patterned YBCO thin films, was measured using a suspended line resonator in the presence of a perpendicular DC magnetic field, H/sub DC/, of magnitude comparable to that of the microwave field, H/sub rf/. Signature of the virgin state was found to be absent even for relatively low microwave power levels. The microwave loss was initially found to decrease for small applied H/sub DC/ before increasing again. Also, non-linearities inherent in the sample were found to be substantially suppressed at low powers at these applied fields. These two features together can lead to significant improvement in device performance.
A Computational Decision Theory for Interactive Assistants

We study several classes of interactive assistants from the points of view of decision theory and computational complexity. We first introduce a class of POMDPs called hidden-goal MDPs (HGMDPs), which formalize the problem of interactively assisting an agent whose goal is hidden and whose actions are observable. In spite of its restricted nature, we show that optimal action selection in finite horizon HGMDPs is PSPACE-complete even in domains with deterministic dynamics. We then introduce a more restricted model called helper action MDPs (HAMDPs), where the assistant's action is accepted by the agent when it is helpful, and can be easily ignored by the agent otherwise. We show classes of HAMDPs that are complete for PSPACE and NP along with a polynomial time class. Furthermore, we show that for general HAMDPs a simple myopic policy achieves a regret, compared to an omniscient assistant, that is bounded by the entropy of the initial goal distribution. A variation of this policy is shown to achieve worst-case regret that is logarithmic in the number of goals for any goal distribution.
Conditional Random Field Autoencoders for Unsupervised Structured Prediction

We introduce a framework for unsupervised learning of structured predictors with overlapping, global features. Each input's latent representation is predicted conditional on the observed data using a feature-rich conditional random field (CRF). Then a reconstruction of the input is (re)generated, conditional on the latent structure, using a generative model which factorizes similarly to the CRF. The autoencoder formulation enables efficient exact inference without resorting to unrealistic independence assumptions or restricting the kinds of features that can be used. We illustrate connections to traditional autoencoders, posterior regularization, and multi-view learning. We then show competitive results with instantiations of the framework for two canonical tasks in natural language processing: part-of-speech induction and bitext word alignment, and show that training the proposed model can be substantially more efficient than a comparable feature-rich baseline.
Expansion and search in networks

Borrowing from concepts in expander graphs, we study the expansion properties of real-world, complex networks (e.g. social networks, unstructured peer-to-peer or P2P networks) and the extent to which these properties can be exploited to understand and address the problem of decentralized search. We first produce samples that concisely capture the overall expansion properties of an entire network, which we collectively refer to as the expansion signature. Using these signatures, we find a correspondence between the magnitude of maximum expansion and the extent to which a network can be efficiently searched. We further find evidence that standard graph-theoretic measures, such as average path length, fail to fully explain the level of "searchability" or ease of information diffusion and dissemination in a network. Finally, we demonstrate that this high expansion can be leveraged to facilitate decentralized search in networks and show that an expansion-based search strategy outperforms typical search methods.
Approximability and proof complexity

This work is concerned with the proof-complexity of certifying that optimization problems do not have good solutions. Specifically we consider bounded-degree "Sum of Squares" (SOS) proofs, a powerful algebraic proof system introduced in 1999 by Grigoriev and Vorobjov. Work of Shor, Lasserre, and Parrilo shows that this proof is automatizable using semidefinite programming (SDP), meaning that any n-variable degree-d proof can be found in time nO(d). Furthermore, the SDP is dual to the well-known Lasserre SDP hierarchy, meaning that the "d/2-round Lasserre value" of an optimization problem is equal to the best bound provable using a degree-d SOS proof. These ideas were exploited in a recent paper by Barak et al. (STOC 2012) which shows that the known "hard instances" for the Unique-Games problem are in fact optimally solved by a constant level of the Lasserre SDP hierarchy.We continue the study of the power of SOS proofs in the context of difficult optimization problems. In particular, we show that the Balanced-Separator integrality gap instances proposed by Devanur et al. can have their optimal value certified by a degree-4 SOS proof. The key ingredient is an SOS proof of the KKL Theorem. We also investigate the extent to which the Khot--Vishnoi Max-Cut integrality gap instances can have their optimum value certified by an SOS proof. We show they can be certified to within a factor .952 (> .878) using a constant-degree proof. These investigations also raise an interesting mathematical question: is there a constant-degree SOS proof of the Central Limit Theorem?
Convergence Rates of Biased Stochastic Optimization for Learning Sparse Ising Models

We study the convergence rate of stochastic optimization of exact (NP-hard) objectives, for which only biased estimates of the gradient are available. We motivate this problem in the context of learning the structure and parameters of Ising models. We first provide a convergence-rate analysis of deterministic errors for forward-backward splitting (FBS). We then extend our analysis to biased stochastic errors, by first characterizing a family of samplers and providing a high probability bound that allows understanding not only FBS, but also proximal gradient (PG) methods. We derive some interesting conclusions: FBS requires only a logarithmically increasing number of random samples in order to converge (although at a very low rate); the required number of random samples is the same for the deterministic and the biased stochastic setting for FBS and basic PG; accelerated PG is not guaranteed to converge in the biased stochastic setting.
Benzannulated Bicycles by Three-Component Aryne Reactions†

Triple crown: A pair of three-component coupling reactions between arynes, isocyanides, and either activated alkynes or phenyl esters generates unusual iminoindenones or phenoxy iminoisobenzofurans (see scheme), the latter of which may be advanced to o-ketobenzamides by performing direct hydrolysis. The synthetic utility of these compounds is demonstrated in a rapid preparation of substituted dibenzoketocaprolactams.
Dynamic Testing of Wholesale Power Market Designs: An Open-Source Agent-Based Framework

In April 2003 the U.S. Federal Energy Regulatory Commission proposed a complicated market design--the Wholesale Power Market Platform (WPMP)--for common adoption by all US wholesale power markets. Versions of the WPMP have been implemented in New England, New York, the mid-Atlantic states, the Midwest, the Southwest, and California. Strong opposition to the WPMP persists among some industry stakeholders, however, due largely to a perceived lack of adequate performance testing. This study reports on the model development and open-source implementation (in Java) of a computational wholesale power market organized in accordance with core WPMP features and operating over a realistically rendered transmission grid. The traders within this market model are strategic profit-seeking agents whose learning behaviors are based on data from human-subject experiments. Our key experimental focus is the complex interplay among structural conditions, market protocols, and learning behaviors in relation to short-term and longer-term market performance. Findings for a dynamic 5-node transmission grid test case are presented for concrete illustration.
The Evolution of the Black-White Test Score Gap in Grades K–3: The Fragility of Results

Although both economists and psychometricians typically treat them as interval scales, test scores are reported using ordinal scales. Using the Early Childhood Longitudinal Study (ECLS-K) and the C...
Interface effects in spin-dependent tunneling

Abstract In the past few years the phenomenon of spin-dependent tunneling (SDT) in magnetic tunnel junctions (MTJs) has aroused enormous interest and has developed into a vigorous field of research. The large tunneling magnetoresistance (TMR) observed in MTJs garnered much attention due to possible application in random access memories and magnetic field sensors. This led to a number of fundamental questions regarding the phenomenon of SDT. One such question is the role of interfaces in MTJs and their effect on the spin polarization of the tunneling current and TMR. In this paper we consider different models which suggest that the spin polarization is primarily determined by the electronic and atomic structure of the ferromagnet/insulator interfaces rather than by their bulk properties. First, we consider a simple tight-binding model which demonstrates that the existence of interface states and their contribution to the tunneling current depend on the degree of hybridization between the orbitals on metal and insulator atoms. The decisive role of the interfaces is further supported by studies of spin-dependent tunneling within realistic first-principles models of Co/vacuum/Al, Co/Al 2 O 3 /Co, Fe/MgO/Fe, and Co/SrTiO 3 /Co MTJs. We find that variations in the atomic potentials and bonding strength near the interfaces have a profound effect resulting in the formation of interface resonant states, which dramatically affect the spin polarization and TMR. The strong sensitivity of the tunneling spin polarization and TMR to the interface atomic and electronic structure dramatically expands the possibilities for engineering optimal MTJ properties for device applications.
On the Rate of Detectability of Intermediate-Mass Black Hole Binaries Using LISA

We estimate the rate at which the proposed space gravitational-wave interferometer LISA could detect intermediate-mass black hole (IMBH) binaries, that is, binaries containing a black hole in the mass range 10-100 M☉ orbiting a black hole in the mass range 100-1000 M☉. For 1 yr integrations leading up to the innermost stable circular orbit and a signal-to-noise ratio of 10, we estimate a detection rate of only 1 per million years for 10 M☉/100 M☉ binaries. The estimate uses the method of parameter estimation via matched filtering, incorporates a noise curve for LISA established by the LISA Science Team that is available online, and employs an IMBH formation rate model used by Miller in 2002. We find that the detectable distance is relatively insensitive to LISA arm lengths or acceleration noise but is roughly inversely proportional to LISA position errors and varies roughly as T1/2, where T is the integration time in years. We also show that while all IMBH systems in this mass range may be detected in the Virgo cluster up to 40 yr before merger, none can be detected there earlier than 400 yr before merger. An extended LISA mission that enabled 10 yr integrations could detect IMBH systems at the Virgo cluster 1000 yr before merger, and systems in Galactic globular clusters 1 million yr before merger. We compare and contrast these estimates with earlier estimates by Miller.
Pressure balance across magnetic flux ropes in the ionosphere of Venus

[1] The planet Venus has a dense atmosphere, and hence an ionosphere, and does not possess an intrinsic magnetic field. The solar wind interacts directly with the atmosphere and ionosphere of Venus. The Pioneer Venus Orbiter (PVO) observed many small-scale magnetic rope-like structures within the ionosphere. We examine thermal pressure variations for ∼2000 ropes for a wide range of altitudes and solar zenith angles. We demonstrate that flux ropes are statistically force-free at low altitudes, meaning that a decrease of thermal pressure variation across them is not needed to compensate for the magnetic pressure in these ropes. However, at higher altitudes, there is a statistical tendency for ropes to display a thermal pressure variation across them, indicating that these ropes are not fully force-free.
Pulsar jets: implications for neutron star kicks and initial spins

We study implications for the apparent alignment of the spin axes, proper motion directions, and polarization vectors of the Crab and Vela pulsars. The spin axes are deduced from recent Chandra X-Ray Observatory images that reveal jets and nebular structure having de—nite symmetry axes. The alignments indicate that these pulsars were born either in isolation or with negligible velocity contribu- tions from binary motions. We examine the eUects of rotation and the conditions under which spin-kick alignment is produced for theoretical models of neutron star kicks. If the kick is generated promptly during the formation of the neutron star by asymmetric mass ejection and/or neutrino emission, then the alignment requires that the protoneutron star possess, by virtue of the precollapse stellar cores spin, an original spin with period much less than the kick timescale thus spin averaging the kick forces P s q kick , on the star. The kick timescale ranges from 100 ms to 10 s depending on whether the kick is hydrody- namically driven or neutrinomagnetic —eld driven. For hydrodynamical models, spin-kick alignment further requires the rotation period of an asymmetry pattern at the radius near shock breakout (Z100 km) to be much less than ms; this is difficult to satisfy unless rotation plays a dynamically q kick ( 100 important role in the core collapse and explosion (corresponding to ms). Aligned kick and spin P s ( 1 vectors are inherent to the slow process of asymmetric electromagnetic radiation from an oU-centered magnetic dipole. We reassess the viability of this electromagnetic rocket eUect, correcting a factor of 4 error in Harrison and Tademarus calculation that increases the size of the eUect. To produce a kick velocity of order a few hundred kilometers per second requires that the neutron star be born with P s D 1 ms and that spin-down due to r-modedriven gravitational radiation be inefficient compared to standard magnetic braking. The electromagnetic rocket operates on a timescale of order 0.3(B/1013 G)~2 yr. The apparent spin-kick alignment in the Crab and Vela pulsars places important new constraints on each of the mechanisms of neutron star kicks that we consider. Subject headings: pulsars: individual (PSR B0531)21, PSR B0833(45) ¨ stars: neutron ¨ stars: rotationsupernovae: general
Two effective procedures for the synthesis of trichloromethyl ketones, useful precursors of chiral α-amino and α-hydroxy acids

Abstract Trichloroacetic acid can been converted to trichloromethyl ketones in good yield by two practical new procedures, one involving the catalyzed reaction of trichloroacetic acid with aldehydes at 23 °C followed by oxidation and the other utilizing the coupling of organozinc intermediates with trichloroacetyl chloride
Estimating the Economic Model of Crime: Employment Versus Punishment Effects

Ann Dryden Witte [1980] has recently argued in this Journal that new support is found for the deterrent hypothesis (or the "economic model of crime") when individual data are employed to estimate the determinants of rearrest rates. Witte estimates a conventional economic model of crime using a rich and carefully constructed microdata set of released prisoners in North Carolina. Her principal findings are that (1) increases in the certainty and severity of punishment tend to reduce participation in crime (measured by number of arrests or convictions per month free), and (2) higher legal wages have an extremely weak deterrent effect on crime. In this comment I describe two separate data sets within which I find just the opposite results. Using a sample of offenders released from federal prisons in 1972, I find that increases in the severity of punishment are weakly related to participation in crime, while increases in the certainty of punishment are positively related to participation in crime. In addition, using a sample of male repeat property offenders released from Maryland prisons, I find that higher wages have a strong and consistent deterrent effect on crime. The conclusion is reached, at least from these data sets, that improving legitimate employment opportunities may be as effective, if not more effective, in reducing crime as is an increase in punishment.
Pattern Recognition Using Invariants Defined From Higher Order Spectra- One Dimensional Inputs

A new approach to pattern recognition using in- variant parameters based on higher order spectra is presented. In particular, invariant parameters derived from the bispec- trum are used to classify one-dimensional shapes. The bispec- trum, which is translation invariant, is integrated along straight lines passing through the origin in bifrequency space. The phase of the integrated bispectrum is shown to be scale and amplifi- cation invariant, as well. A minimal set of these invariants is selected as the feature vector for pattern classification, and a minimum distance classifier using a statistical distance measure is used to classify test patterns. The classification technique is shown to distinguish two similar, but different bolts given their one-dimensional profiles. Pattern recognition using higher or- der spectral invariants is fast, suited for parallel implementa- tion, and has high immunity to additive Gaussian noise. Sim- ulation results show very high classification accuracy, even for low signal-to-noise ratios.
Online distributed sensor selection

A key problem in sensor networks is to decide which sensors to query when, in order to obtain the most useful information (e.g., for performing accurate prediction), subject to constraints (e.g., on power and bandwidth). In many applications the utility function is not known a priori, must be learned from data, and can even change over time. Furthermore for large sensor networks solving a centralized optimization problem to select sensors is not feasible, and thus we seek a fully distributed solution. In this paper, we present Distributed Online Greedy (DOG), an efficient, distributed algorithm for repeatedly selecting sensors online, only receiving feedback about the utility of the selected sensors. We prove very strong theoretical no-regret guarantees that apply whenever the (unknown) utility function satisfies a natural diminishing returns property called submodularity. Our algorithm has extremely low communication requirements, and scales well to large sensor deployments. We extend DOG to allow observation-dependent sensor selection. We empirically demonstrate the effectiveness of our algorithm on several real-world sensing tasks.
The block-processing FTF adaptive algorithm

A new block-type adaptive-filtering algorithm is presented. This new block adaptive filter differs from the frequency-domain block adaptive filters of Ferrara (1980), and of Clark, Mitra, and Parker (1980), in that the new method applies a deterministic time-domain least-squares criteria within each of the data blocks. Information is carried from block to block via a weighted initial condition. This new block fast transversal filters (BFTF) algorithm is a numerically stable algorithm and can also be used to perform efficient least-squares system identification on any one data block, in which case it shows a moderate computational advantage over the previous most-efficient single-data-block algorithms of Morf et al. (1977), of Marple (1981), and of Kalouptsidis, Manolakis, and Carayannis (1984-1985). Mechanisms for tracking and varying block length from block to block are also presented and evaluated. Finally, we indicate how the new algorithm could be pipelined for maximum throughput with delay proportional to the number of parameters, after computation of the sample correlation lags.
Restoration of hippocampal growth hormone reverses stress-induced hippocampal impairment.

Though growth hormone (GH) is synthesized by hippocampal neurons, where its expression is influenced by stress exposure, its function is poorly characterized. Here, we show that a regimen of chronic stress that impairs hippocampal function in rats also leads to a profound decrease in hippocampal GH levels. Restoration of hippocampal GH in the dorsal hippocampus via viral-mediated gene transfer completely reversed stress-related impairment of two hippocampus-dependent behavioral tasks, auditory trace fear conditioning and contextual fear conditioning, without affecting hippocampal function in unstressed control rats. GH overexpression reversed stress-induced decrements in both fear acquisition and long-term fear memory. These results suggest that loss of hippocampal GH contributes to hippocampal dysfunction following prolonged stress and demonstrate that restoring hippocampal GH levels following stress can promote stress resilience.
Influence of aerodynamic forces in ice shedding

Stresses in accreted ice on a typical airfoil impact ice caused by aerodynamic forces have been studied using finite element analyses. The objective of this study is to determine the significance of these stresses relative to values needed to cause ice shedding. In the case studied, stresses are not significant (less than 10 percent) when compared to the fracture value for airspeeds below a Mach number of 0.45. Above this velocity, the influence of aerodynamic forces on impact ice stresses should be considered in analyses of ice shedding.
Should Student Employment Be Subsidized? Conditional Counterfactuals and the Outcomes of Work-Study Participation

Abstract Student employment subsidies are one of the largest types of federal employment subsidies, yet little is known about their impact. We provide a framework highlighting the likelihood of heterogeneity in program effects, depending upon whether recipients are marginal or inframarginal workers. We then utilize a matching approach to estimate the effects of the Federal Work-Study program, leveraging the fact that FWS funding varies across institutions for idiosyncratic reasons. Our results suggest that about half of FWS participants would have worked even in the absence of the subsidy; for these students, FWS reduces hours worked and improves academic outcomes, but has little impact on early post-college employment. For students who would not have worked otherwise, the pattern of effects reverses. Overall, the positive effects are strongest for subgroups who are the least likely to have access to the program, suggesting there may be gains to improved targeting of funds.
Low-temperature behavior of the Abelian Higgs model in Anti-de Sitter space

We explore the low-temperature behavior of the Abelian Higgs model in AdS4, away from the probe limit in which back-reaction of matter fields on the metric can be neglected. Over a significant range of charges for the complex scalar, we observe a second order phase transition at finite temperature. The symmetry-breaking states are superconducting black holes. At least when the charge of the scalar is not too small, we observe at low temperatures the emergence of a domain wall structure characterized by a definite index of refraction. We also compute the conductivity as a function of frequency.
Gamma Ray Background Analysis at the NASA Langley Research Center SREL 600 MeV Proton Synchrocyclotron of the Relatively Short- and Long-Lived Gamma Rays

Gamma ray background near proton synchrocyclotron beam degrader at NASA-LRC Space Radiation Effects Laboratory
Efficient Minimization of Decomposable Submodular Functions

Many combinatorial problems arising in machine learning can be reduced to the problem of minimizing a submodular function. Submodular functions are a natural discrete analog of convex functions, and can be minimized in strongly polynomial time. Unfortunately, state-of-the-art algorithms for general submodular minimization are intractable for larger problems. In this paper, we introduce a novel subclass of submodular minimization problems that we call decomposable. Decomposable submodular functions are those that can be represented as sums of concave functions applied to modular functions. We develop an algorithm, SLG, that can efficiently minimize decomposable submodular functions with tens of thousands of variables. Our algorithm exploits recent results in smoothed convex minimization. We apply SLG to synthetic benchmarks and a joint classification-and-segmentation task, and show that it outperforms the state-of-the-art general purpose submodular minimization algorithms by several orders of magnitude.
Cascade synthesis of finite-state machines

One can construct any finite-state machine as a cascade interconnection of machines whose inputs either permute the states or reset them all to one state. Each permutation group needed in the construction is a homomorphic image of a group generated by the action of a set of input sequences on a state subset of the original machine. Proofs of these facts will be given and their application to the Krohn-Rhodes theory described.
Proteomic responses of oceanic Synechococcus WH8102 to phosphate and zinc scarcity and cadmium additions

Synechococcus sp. WH 8102 is a motile marine cyanobacterium isolated originally from the Sargasso Sea. To test the response of this organism to cadmium (Cd) -generally considered a toxin- cultures were grown in a matrix of high and low zinc (Zn) and phosphate (PO43-) and were then exposed to an addition of 4.4 pM free Cd2+ at mid-log phase and harvested after 24 h. Whereas Zn and PO43- had little effect on overall growth rates, in the final 24 h of the experiment three growth effects were noticed: i) low PO43- treatments showed increased growth rates relative to high PO43- treatments, ii) the Zn/high PO43- treatment appeared to enter stationary phase, and iii) Cd increased growth rates further in both the low PO43- and Zn treatments. Global proteomic analysis revealed that: i) Zn appeared to be critical to the PO43- response in this organism, ii) bacterial metallothionein (SmtA) appears correlated with PO43- stress-associated proteins, iii) Cd has the greatest influence on the proteome at low PO43- and Zn, iv) Zn buffered the effects of Cd, and v) in the presence of both replete PO43- and added Cd the proteome showed little response to the presence of Zn. Similar trends in alkaline phosphate (ALP) and SmtA suggest the possibility of a Zn supply system to provide Zn to ALP that involves SmtA. In addition, proteome results were consistent with a previous transcriptome study of PO43- stress (with replete Zn) in this organism, including the greater relative abundance of ALP (PhoA), ABC phosphate binding protein (PstS) and other proteins. Yet with no Zn in this proteome experiment the PO43- response was quite different including the greater relative abundance of five hypothetical proteins with no increase in PhoA or PstS, suggesting that Zn nutritional levels are connected to the PO43- response in this cyanobacterium. Alternate ALP PhoX (Ca) was found to be a low abundance protein, suggesting that PhoA (Zn, Mg) may be more environmentally relevant than PhoX.
Reals n-generic relative to some perfect tree

We say that a real X is ?-generic relative to a perfect tree T if X is a path through T and for all L?? (T) sets S. there exists a number k such that either X\k G S or for all o G T extending X\k we have a $l S. A real X is ? -generic relative to some perfect tree if there exists such a T. We first show that for every number n all but countably many reals are ?-generic relative to some perfect tree. Second, we show that proving this statement requires ZFC~ + "3 infinitely many iterates of the power set of co'\ Third. we prove that every finite iterate of the hyperjump. &{l]]. is not 2-generic relative to any perfect tree and for every ordinal a below the least a such that sup?<; (/?th admissible) = /,, the iterated hyperjump &{a] is not 5-generic relative to any perfect tree. Finally, we demonstrate some necessary conditions for reals to be 1-generic relative to some perfect tree. ?
The Continuing Importance of Political Ties in China

Our paper is a starting point for further discussions on the value of political ties in China, their evolutionary trajectory along the process of globalization, and their influence in explaining variability in differentiated performance metrics. We hope that our work will provide an impetus for additions and extensions that view convergence and divergence as two interrelated and mutually dependent constructs. Ignoring one or the other might generate an incomplete view of the effects of globalization.
Multilevel Coding Schemes for Compute-and-Forward With Flexible Decoding

We consider the design of coding schemes for the wireless two-way relaying channel when there is no channel state information at the transmitter. In the spirit of the compute-and-forward paradigm, we present a multilevel coding scheme that permits reliable computation (or, decoding) of a class of functions at the relay. The function to be computed (or decoded) is then chosen depending on the channel realization. We define such a class of functions which can be decoded at the relay using the proposed coding scheme and derive rates that are universally achievable over a set of channel gains when this class of functions is used at the relay. We develop our framework with general modulation formats in mind, but numerical results are presented for the case where each node transmits using 4-ary and 8-ary modulation schemes. Numerical results demonstrate that the flexibility afforded by our proposed scheme results in substantially higher rates than those achievable by always using a fixed function or considering only linear functions over higher order fields.
Propagation of spin-polarized electrons through interfaces separating differently doped semiconductor regions

High degree of electron spin polarization is of crucial importance in operation of spintronic devices. We study the propagation of spin-polarized electrons through a boundary between two n-type semiconductor regions with different doping levels. We assume that inhomogeneous spin polarization is created/injected locally and driven through the boundary by the electric field. The electric field distribution and spin polarization distribution are calculated within a two-component drift-diffusion transport model. We show that an initially created narrow region of spin polarization can be further compressed and amplified near the boundary. Since the boundary involves variation of doping but no real interface between two semiconductor materials, no significant spin-polarization loss is expected. The proposed mechanism will be therefore useful in designing new spintronic devices.
Influence of planetary-scale topography on the diurnal thermal tide during the 1971 Martian dust storm

Data obtained with the Mariner 9 infrared spectroscopy experiment during the Martian dust storm of 1971-72 are examined for evidence of topographic influence on the atmospheric thermal structure. Temperature perturbations which are well correlated with the planetary-scale topography are found superposed on the large-amplitude diurnal thermal tide previously reported. Applications of tidal theory to the data indicate that the observed perturbations result from the kinematic interaction of the westward traveling diurnal wave with the large-scale components of topography. The dominant mode is excited by the wavenumber 2 topography component and is a vertically evanescent, eastward traveling wave with an equivalent depth comparable to the atmospheric-scale height. The principle dynamic effect of this mode is the enhancement of the amplitude of the near-surface diurnal wind to over 40 m/s in limited areas near 30 deg S latitude. Thus, it appears likely that dust was injected into the atmosphere in these regions during the storm. Other waves excited include vertically propagating modes which produce little effect in the lower atmosphere, but may represent a source of energy for the upper atmosphere during dust storm conditions.
Model reference adaptive control for plants with unknown relative degree

A parameterization scheme for model reference control which guarantees stable model-plant transfer function matching is presented. This scheme has a linear dynamic feedforward block whose numerator and denominator should be stable polynomials for closed-loop stability. An adaptive law is designed to update the controller parameters in the feedback loop and the coefficients of the numerator of the feedforward block as well as some additional parameters. Since, for stability, the inverse of the polynomial differential operator defined by some of the estimated parameters has to be stable, the adaptive law is modified using a projection technique. The stability analysis of the model reference adaptive control (MRAC) scheme is given. The robustness of the MRAC scheme with respect to unmodeled dynamics is established. >