cssi/SciSciGPT-SciSciNet huggingface dataset:
Ambient Schmittel Cyclization Promoted by Chemoselective Triazole-Gold Catalyst

The Schmittel cyclization was achieved at room temperature through triazole–gold (TA–Au) catalyzed propargyl vinyl ether rearrangement. Other tested [L–Au]+ catalysts gave complex reaction mixtures under identical conditions with no desired products observed. Importantly, because of the employment of mild conditions, sterically hindered groups (such as t-Bu) on allene termini were no longer required, which allowed successful synthesis of previously challenging substrates.
PayCash: a secure efficient internet payment system

Abstract This paper describes PayCash, an Internet payment system that was designed to offer strong security and privacy protection. This system is based on the concept of electronic cash, extended to support a flexible anonymity policy so as to accommodate privacy and security laws that differ from nation to nation. PayCash includes novel techniques to generate trustworthy records of all transactions, making it possible to detect many forms of fraud. This system also allows users to send a variable number of “electronic coins” in a single message, so both large and small amounts of money can be transferred efficiently.
The BNL accelerator test facility and experimental program

The Accelerator Test Facility (ATF) at BNL (Brookhaven National Laboratory) is a facility for experiments in accelerator and beam physics. The ATF provides high-brightness electron beams and high-power laser pulses synchronized to the electron beam, suitable for studies of new methods of high-gradient acceleration and state-of-the-art free-electron-lasers. The electrons are produced by a laser photocathode RF gun and accelerated to 50 to 100 MeV by two traveling wave accelerator sections. The lasers include a 10-mJ, 10-ps Nd:YAG laser and a 100-mJ, 10-ps CO/sub 2/ laser. The ATF's experimental program commenced in early 1991 at an energy of about 4 MeV. The full program, with 50 MeV and the high-power laser will begin operation this year. >
Alternating knots, planar graphs, and q-series

Recent advances in Quantum Topology assign $$q$$ -series to knots in at least three different ways. The $$q$$ -series are given by generalized Nahm sums (i.e., special $$q$$ -hypergeometric sums) and have unknown modular and asymptotic properties. We give an efficient method to compute those $$q$$ -series that come from planar graphs (i.e., reduced Tait graphs of alternating links) and compute several terms of those series for all graphs with at most 8 edges drawing several conclusions. In addition, we give a graph-theory proof of a theorem of Dasbach-Lin which identifies the coefficient of $$q^k$$ in those series for $$k=0,1,2$$ in terms of polynomials on the number of vertices, edges, and triangles of the graph.
STAT3 promotes CD1d‐mediated lipid antigen presentation by regulating a critical gene in glycosphingolipid biosynthesis

Cytokines that regulate the immune response signal through the Janus kinase / signal transducer and activation of transcription (JAK/STAT) pathway, but whether this pathway can regulate CD1d-mediated lipid antigen presentation to natural killer T (NKT) cells is unknown. Here, we found that STAT3 promotes antigen presentation by CD1d. Antigen-presenting cells (APCs) in which STAT3 expression was inhibited exhibited markedly reduced endogenous lipid antigen presentation to NKT cells without an impact on exogenous lipid antigen presentation by CD1d. Consistent with this observation, in APCs where STAT3 was knocked down, dramatically decreased levels of UDP glucose ceramide glucosyltransferase (UGCG), an enzyme involved in the first step of glycosphingolipid biosynthesis, were observed. Impaired lipid antigen presentation was reversed by ectopic expression of UGCG in STAT3-silenced CD1d(+) APCs. Hence, by controlling a fundamental step in CD1d-mediated lipid antigen presentation, STAT3 signalling promotes innate immune responses driven by CD1d.
Insertion devices for the Advanced Light Source at LBL

The Advanced Light Source (ALS) at the Lawrence Berkeley Laboratory (LBL) will be the first of the new generation of dedicated synchrotron light sources to be put into operation. Specially designed insertion devices will be required to realize the high-brightness photon beams made possible by the low emittance of the electron beam. The complement of insertion devices on the ALS will include undulators with periods as short as 3.9 cm and one or more high field wigglers. The first device to be designed is a 5-m-long, 5-cm-period, hybrid undulator. The goal of very high brightness and high harmonic output imposes unusually tight tolerances on the magnetic field quality and thus on the mechanical structure. The design process, using a generic structure for all undulators, is described. >
Rainfall Forecasts, Weather, and Wages over the Agricultural Production Cycle

We look at the effects of rainfall forecasts and realized rainfall on equilibrium agricultural wages over the course of the agricultural production cycle. We show theoretically that a forecast of good weather can lower wages in the planting stage, by lowering ex ante out-migration, and can exacerbate the negative impact of adverse weather on harvest-stage wages. Using Indian household panel data describing early-season migration and district-level planting- and harvest-stage wages over the period 2005-2010, we find results consistent with the model, indicating that rainfall forecasts improve labor allocations on average but exacerbate wage volatility because they are imperfect.
Congruences for Catalan and Motzkin numbers and related sequences

We prove various congruences for Catalan and Motzkin numbers as well as related sequences. The common thread is that all these sequences can be expressed in terms of binomial coefficients. Our techniques are combinatorial and algebraic: group actions, induction, and Lucas’ congruence for binomial coefficients come into play. A number of our results settle conjectures of Cloitre and Zumkeller. The Thue–Morse sequence appears in several contexts.
Transfers of Meaning

L'A. examine les transferts de significations en anglais, operation dans laquelle des noms de propriete sont transferes dans de nouveaux noms qui denotent des proprietes auxquelles ils correspondent fonctionnellement. C'est cette operation qui est responsable du nouveau sens du predicat parked out back dans l'enonce I am parked out back, ainsi que des alternances lexicales representees en polysemie systematique
Superconformal indices of generalized Argyres-Douglas theories from 2d TQFT

We study superconformal indices of 4d $$ \mathcal{N}=2 $$ class S theories with certain irregular punctures called type I k,N . This class of theories include generalized Argyres-Douglas theories of type (A k−1 , A N −1) and more. We conjecture the superconformal indices in certain simplified limits based on the TQFT structure of the class S theories by writing an expression for the wave function corresponding to the puncture I k,N . We write the Schur limit of the wave function when k and N are coprime. When k = 2, we also conjecture a closed-form expression for the Hall-Littlewood index and the Macdonald index for odd N. Fromtheindex,wearguethatcertainshort-multipletwhichcanappearintheOPEof the stress-energy tensor is absent in the (A 1 , A 2n ) theory. We also discuss the mixed Schur indices for the $$ \mathcal{N}=1 $$ class $$ \mathcal{S} $$ theories with irregular punctures.
High-energy neutron radiography

High-energy spallation neutron sources are now being considered in the US and elsewhere as a replacement for neutron beams produced by reactors. High-energy and high intensity neutron beams, produced by unmoderated spallation sources, open potential new vistas of neutron radiography. We discuss the basic advantages and disadvantages of high- energy neutron radiography, and consider some experimental results obtained at the Weapons Neutron Research facility at Los Alamos.
Precision measurements of the top quark mass from the Tevatron in the pre-LHC era.

The top quark is the heaviest of the six quarks of the standard model (SM). Precise knowledge of its mass is important for imposing constraints on a number of physics processes, including interactions of the as yet unobserved Higgs boson. The Higgs boson is the only missing particle of the SM, central to the electroweak symmetry breaking mechanism and generation of particle masses. In this review, experimental measurements of the top quark mass accomplished at the Tevatron, a proton-antiproton collider located at the Fermi National Accelerator Laboratory, are described. Topologies of top quark events and the methods used to separate signal events from background sources are discussed. Data analysis techniques used to extract information about the top mass value are reviewed. The combination of several of the most precise measurements performed with the two Tevatron particle detectors, CDF and DO, yields a value of M(t) = 173.2 ± 0.9 GeV/c(2).
"Carbon dichloride": dihalocarbenes sixty years after Hine.

We describe new syntheses of dichlorodiazirine, difluorodiazirine, and chlorofluorodiazirine. From these precursors, laser flash photolysis enables the generation of CCl2, CF2, and CClF. We describe the formation and chemistry of bromodichloromethide carbanion from CCl2, the ambiplilicity of CCl2, the complexation of CCl2 by aromatic ethers, and the kinetics and activation parameters attending the additions of CCl2, CF2, and CClF to several alkenes.
Letting the brain speak for itself.

Metaphors of Computation and Information tended to detract attention from the intrinsic modes of neural system functions, uncontaminated by the observer’s role in collection and interpretation of experimental data. Recognizing the self-referential mode of function, and the propensity for self-organization to critical states requires a fundamentally new orientation, based on Complex System Dynamics as non-ergodic, non-stationary processes with inverse power-law statistical distributions. Accordingly, local cooperative processes, intrinsic to neural structures and of fractal nature, call for applying Fractional Calculus and models of Random Walks with long-term memory in Theoretical Neuroscience studies.
On Coloring the Odd-Distance Graph

We present a proof, using spectral techniques, that there is no finite measurable coloring of the odd-distance graph. Let O be the graph with V (O) = R 2 and where two vertices are connected if they are at an odd distance from each other. We call O the odd-distance graph. Let the measurable chromatic number of a graph denote the least number of colors needed to color a graph such that each color class is measurable. We aim to show that the measurable chromatic number χ of O is infinite. We will do this by defining a sequence of operators Brelated to the adjacency operator of O. We then use an extension of the well-known spectral inequality, χ(G) ≥ 1 − �max �min , to the infinite-dimensional case. We next determine the set of eigenfunctions for B� (they turn out to be the characters of R 2 , though this is in a sense guaranteed from the Fourier analysis on R 2 ). This gives us the full set of eigenvalues for the B�, which we then bound below in order to show that 1 − �max �min goes to ∞ as α goes to 1. As this is a lower bound for χ(O), we will then have established that O has infinite measurable chromatic number. Throughout the paper, whenever we refer to chromatic number we will always mean measurable chromatic number. This result has been proven elsewhere, for example as a consequence of the theorem that all measurable sets with positive density at infinity contain all sufficiently large distances (see e.g. (2)). However, the proof in this paper uses primarily techniques from spectral graph theory rather than measure theory and seems to be closer in spirit to the problem itself. See also (1) where a similar generalization of the Lovasz theta function is studied and used to derive new bounds on the chromatic number of unit-distance graphs in R n .
Development and Application of an Anisotropic Two-Equation Model for Flows With Swirl and Curvature

An anisotropic two-equation model is developed through a novel technique that involves the representation of the energy spectrum and invariance based scaling. In this approach the effect of rotation is used to modify the energy spectrum, while the influence of swirl is modeled based on scaling laws. The resulting generalized two-equation turbulence model is validated for several benchmark turbulent flows with swirl and curvature.
Intramolecular Redox-Mannich Reactions: Facile Access to the Tetrahydroprotoberberine Core.

Cyclic amines such as pyrrolidine undergo redox-annulations with 2-formylaryl malonates. Concurrent oxidative amine α-CH bond functionalization and reductive N-alkylation render this transformation redox-neutral. This redox-Mannich process provides regioisomers of classic Reinhoudt reaction products as an entry to the tetrahydroprotoberberine core, enabling the synthesis of (±)-thalictricavine and its epimer. An unusually mild amine-promoted dealkoxycarbonylation was discovered in the course of these studies.
Collaborative routing, scheduling and frequency assignment for wireless Ad Hoc networks using spectrum-agile radios

We present the CROWN (Collaborative ROuting, scheduling and frequency assignment for Wireless ad hoc Networks) scheme. CROWN is a cross-layer optimization approach for spectrum-agile nodes to adjust their spectrum allocation and transmission scheduling according to the underlying traffic demands. Instead of choosing the optimal route based on predetermined transmission scheduling and frequency assignment results, CROWN incorporates the efficiency of the underlying frequency assignment and scheduling information into the routing metric calculation, so that the route with the maximal joint spatial and frequency reuse is selected. Simulation results show that CROWN efficiently exploits the frequency diversity and spatial reuse features of spectrum-agile radios.
Adaptive Restart for Accelerated Gradient Schemes

In this paper we introduce a simple heuristic adaptive restart technique that can dramatically improve the convergence rate of accelerated gradient schemes. The analysis of the technique relies on the observation that these schemes exhibit two modes of behavior depending on how much momentum is applied at each iteration. In what we refer to as the `high momentum' regime the iterates generated by an accelerated gradient scheme exhibit a periodic behavior, where the period is proportional to the square root of the local condition number of the objective function. Separately, it is known that the optimal restart interval is proportional to this same quantity. This suggests a restart technique whereby we reset the momentum whenever we observe periodic behavior. We provide a heuristic analysis that suggests that in many cases adaptively restarting allows us to recover the optimal rate of convergence with no prior knowledge of function parameters.
A Special Class of Almost Disjoint Families

The collection of branches (maximal linearly ordered sets of nodes) of the tree <ωω (ordered by inclusion) forms an almost disjoint family (of sets of nodes). This family is not maximal — for example, any level of the tree is almost disjoint from all of the branches. How many sets must be added to the family of branches to make it maximal? This question leads to a series of definitions and results: a set of nodes is off-branch if it is almost disjoint from every branch in the tree; an off-branch family is an almost disjoint family of off-branch sets; and is the minimum cardinality of a maximal off-branch family.Results concerning include: (in ZFC) , and (consistent with ZFC) is not equal to any of the standard small cardinal invariants or = 2ω. Most of these consistency results use standard forcing notions—for example, in the Cohen model.Many interesting open questions remain, though—for example, whether .
Computation of acoustic waves through sliding-zone interfaces using an Euler/Navier-Stokes code

The effect of a patched sliding-zone interface on the transmission of acoustic waves is examined for two- and three-dimensional model problems. A simple but general interpolation scheme at the patched boundary passes acoustic waves without distortion, provided that a sufficiently small time step is taken. A guideline is provided for the maximum permissible time step or zone speed that gives an acceptable error introduced by the sliding-zone interface.
A 1 GHz CMOS RF front-end IC for a direct-conversion wireless receiver

An integrated low-noise amplifier and downconversion mixer operating at 1 GHz has been fabricated for the first time in 1 /spl mu/m CMOS. The overall conversion gain is almost 20 dB, the double-sideband noise figure is 3.2 dB, the IIP3 is +8 dBm, and the circuit takes 9 mA from a 3 V supply. Circuit design methods which exploit the features of CMOS well suited to these functions are in large part responsible for this performance. The front-end is also characterized in several other ways relevant to direct-conversion receivers.
On the topology of graph picture spaces

Abstract We study the space X d (G) of pictures of a graph G in complex projective d-space. The main result is that the homology groups (with integer coefficients) of X d (G) are completely determined by the Tutte polynomial of G. One application is a criterion in terms of the Tutte polynomial for independence in the d-parallel matroids studied in combinatorial rigidity theory. For certain special graphs called orchards, the picture space is smooth and has the structure of an iterated projective bundle. We give a Borel presentation of the cohomology ring of the picture space of an orchard, and use this presentation to develop an analogue of the classical Schubert calculus.
Managerial Expertise, Private Information, and Pay-Performance Sensitivity

This paper characterizes optimal pay-performance sensitivities of compensation contracts for managers who have private information about their skills, and those skills affect their outside employment opportunities. The model presumes that the rate at which a manager's opportunity wage increases in his expertise depends on the nature of that expertise, i.e., whether it is general or firm specific. The analysis demonstrates that when managerial expertise is largely firm specific (general), the optimal pay-performance sensitivity is lower (higher) than its optimal value in a benchmark setting of symmetric information. Furthermore, when managerial skills are largely firm specific (general), the optimal pay-performance sensitivity decreases (increases) as managerial skills become a more important determinant of firm performance. Unlike the standard agency-theoretic prediction of a negative trade-off between risk and pay-performance sensitivity, this paper identifies plausible circumstances under which risk and incentives are positively associated. In addition to providing an explanation for why empirical tests of risk-incentive relationships have produced mixed results, the analysis generates insights that can be useful in guiding future empirical research.
Optimal mechano-electric stabilization of cardiac alternans

Alternation of normal action potential morphology in the myocardium is a condition with a beat-to-beat oscillation in the length of the electric wave which is linked through electromechanical coupling to the cardiac muscle contraction, and is believed to be the first manifestation of the onset of life threatening ventricular arrhythmias and sudden cardiac death. In this work, the effects of electrical and mechanical stimuli are utilized in alternans annihilation problem. Electrical stimuli that alter the action-potential morphology are represented by a pacer located at the domain's boundary, while mechanical stimuli are distributed within the spatial domain and affect the action potential by altering intracellular calcium kinetics. Alternation of action potential is described by the small amplitude of alternans parabolic partial differential equation (PDE). Spatially uniform unstable steady-state of the alternans amplitude PDE is stabilized by optimal control methods through boundary and spatially distributed actuation. Mixed boundary and spatially distributed actuation is manipulated by a finite dimensional linear quadratic regulator (LQR) in the full-state feedback control structure and in a compensator design with a Luenberger-type observer, and it achieves exponential stabilization in a finite size tissue cable length. The proposed control problem formulation and the performance and robustness of the closed-loop system under the proposed linear controller are evaluated through simulations.
Intermittence and nonlinear parabolic stochastic partial differential equations

We consider nonlinear parabolic SPDEs of the form $\partial_t u={\cal L} u + \sigma(u)\dot w$, where $\dot w$ denotes space-time white noise, $\sigma:R\to R$ is [globally] Lipschitz continuous, and $\cal L$ is the $L^2$-generator of a L'evy process. We present precise criteria for existence as well as uniqueness of solutions. More significantly, we prove that these solutions grow in time with at most a precise exponential rate. We establish also that when $\sigma$ is globally Lipschitz and asymptotically sublinear, the solution to the nonlinear heat equation is ``weakly intermittent,'' provided that the symmetrization of $\cal L$ is recurrent and the initial data is sufficiently large. Among other things, our results lead to general formulas for the upper second-moment Liapounov exponent of the parabolic Anderson model for $\cal L$ in dimension $(1+1)$. When ${\cal L}=\kappa\partial_{xx}$ for $\kappa>0$, these formulas agree with the earlier results of statistical physics (Kardar (1987), Krug and Spohn (1991), Lieb and Liniger (1963)), and also probability theory (Bertini and Cancrini (1995), Carmona and Molchanov (1994)) in the two exactly-solvable cases. That is when $u_0=\delta_0$ or $u_0\equiv 1$; in those cases the moments of the solution to the SPDE can be computed (Bertini and Cancrini (1995)).
Weak Asymptotics for Schrödinger Evolution

In this short note, we apply the technique developed in [Math. Model. Nat. Phenom., 5 (2010), No. 4, 122-149] to study the long-time evolution for Schrodinger equation with slowly decaying potential.
Efficiencies of coated and perforated semiconductor neutron detectors

Previous experimental results indicated that boron-filled perforations within a semiconductor diode detector increase the thermal neutron detection efficiency. In this paper, two basic perforation designs, circular holes and parallel trenches, are analyzed using a simple Monte Carlo model to estimate their potential as high-efficiency thermal neutron detectors. The modeling results indicate that thermal-neutron intrinsic detection efficiencies exceeding 25% can be realized for single coated devices, and efficiencies exceeding 50% can be realized for doubled or "sandwiched" devices.
Characterizing and Recognizing Spoken Corrections in Human-Computer Dialogue

Miscommunication in speech recognition systems is unavoidable, but a detailed characterization of user corrections will enable speech systems to identify when a correction is taking place and to more accurately recognize the content of correction utterances. In this paper we investigate the adaptations of users when they encounter recognition errors in interactions with a voice-in/voice-out spoken language system. In analyzing more than 300 pairs of original and repeat correction utterances, matched on speaker and lexical content, we found overall increases in both utterance and pause duration from original to correction. Interestingly, corrections of misrecognition erros (CME) exhibited significantly heightened pitch variability, while corrections of rejection errors (CRE) showed only a small but significant decrease in pitch minimum. CME's demonstrated much greater increases in measures of duration and pitch variability than CRE's. These contrasts allow the development of decision trees which distinguish CME's from CRE's and from original inputs at 70--75% accuracy based on duration, pitch, and amplitude features.
Are lemons really hot potatoes

Abstract We model the hazard rate for car ownership spells. Our model allows us to distinguish among different types of adverse selection effects by observing the type of unobserved heterogeneity across owners of the same car. Our empirical results strongly suggest that there is a lemons effect because there is significant unobserved heterogeneity. However, they also suggest that the lemons effect is caused by the first owner rather than the manufacturer. Had the manufacturer created the lemon, the unobserved heterogeneity would be positively correlated over all owners of a given car. Instead we observe a negative correlation between the unobserved heterogeneity term for the first owner and the unobserved heterogeneity term for subsequent owners.
Collisional Cascades in Planetesimal Disks. I. Stellar Flybys

We use a new multiannulus planetesimal accretion code to investigate the evolution of a planetesimal disk following a moderately close encounter with a passing star. The calculations include fragmentation, gas and Poynting-Robertson drag, and velocity evolution from dynamical friction and viscous stirring. We assume that the stellar encounter increases planetesimal velocities to the shattering velocity, initiating a collisional cascade in the disk. During the early stages of our calculations, erosive collisions damp particle velocities and produce substantial amounts of dust. For a wide range of initial conditions and input parameters, the time evolution of the dust luminosity follows a simple relation, Ld/L* = L0/[α + (t/td)β]. The maximum dust luminosity L0 and the damping time td depend on the disk mass, with L0 ∝ Md and td ∝ M. For disks with dust masses of 1%–100% of the "minimum-mass solar nebula" (1–100 M⊕ at 30–150 AU), our calculations yield td ~ 1–10 Myr, α ≈ 1–2, β = 1, and dust luminosities similar to the range observed in known "debris disk" systems, L0 ~ 10-3 to 10-5. Less massive disks produce smaller dust luminosities and damp on longer timescales. Because encounters with field stars are rare, these results imply that moderately close stellar flybys cannot explain collisional cascades in debris disk systems with stellar ages of ~100 Myr or longer.
Practical traffic grooming scheme for single-hub SONET/WDM rings

In SONET/WDM networks, one fiber supports multiple wavelengths and each wavelength supports several low rate tributary streams. 'Traffic grooming' then is defined as properly using SONET Add/Drop Multiplexer to electronically multiplex and demultiplex required tributary traffic patterns with minimal resource cost (wavelengths and ADMs).This paper studies traffic grooming problem in single hub SONET/WDM networks and extends existing results. We analyze the real deployments, generalize their results, and study the practical special cases. We prove that BLSR/2 would never be more expensive than UPSR under any traffic pattern. We also present the exact minimum costs of uniform traffic in both UPSR and BLSR/2. We give approximation algorithms for optimal grooming of non-uniform traffic. Finally, we consider how to select the line speeds if there are two different line speeds available.
Direct extraction of normal mapped meshes from volume data

We describe a method of directly extracting a simplified contour surface along with detailed normal maps from volume data in one fast and integrated process. A robust dual contouring algorithm is used for efficiently extracting a high-quality "crack-free" simplified surface from volume data. As each polygon is generated, the normal map is simultaneously generated. An underlying octree data structure reduces the search space required for high to low resolution surface normal mapping. The process quickly yields simplified meshes fitted with normal maps that accurately resemble their complex equivalents.
Internal and external labor markets: a personnel economics approach

Abstract Internal labor markets are those where workers are hired into entry level jobs and higher levels are filled from within. Wages are determined internally and may be quite free of market pressure. External labor markets imply that workers move somewhat fluidly between firms and wages are determined by some aggregate process where firms do not have significant discretion over wage setting. There are a number of theories that lead to internal labor markets. Using data from Sweden from the late 1980s, it is found that although there is significant evidence of internal promotion being important, a significant external market exists that affects both wage setting and hiring patterns. Positions are filled by hiring outsiders at all levels of the typical firm. Even in Sweden, where many believe that job mobility is limited by institutional factors, external forces limit firms' ability to set wages. The external forces are likely to reflect both centralized wage bargaining and market factors that take the form of substitute workers available outside the firm.
Biological Database of Images and Genomes: tools for community annotations linking image and genomic information

Genomic data and biomedical imaging data are undergoing exponential growth. However, our understanding of the phenotype–genotype connection linking the two types of data is lagging behind. While there are many types of software that enable the manipulation and analysis of image data and genomic data as separate entities, there is no framework established for linking the two. We present a generic set of software tools, BioDIG, that allows linking of image data to genomic data. BioDIG tools can be applied to a wide range of research problems that require linking images to genomes. BioDIG features the following: rapid construction of web-based workbenches, community-based annotation, user management and web services. By using BioDIG to create websites, researchers and curators can rapidly annotate a large number of images with genomic information. Here we present the BioDIG software tools that include an image module, a genome module and a user management module. We also introduce a BioDIG-based website, MyDIG, which is being used to annotate images of mycoplasmas. Database URL: BioDIG website: http://biodig.org BioDIG source code repository: http://github.com/FriedbergLab/BioDIG The MyDIG database: http://mydig.biodig.org/
Frame coherence and sparse signal processing

The sparse signal processing literature often uses random sensing matrices to obtain performance guarantees. Unfortunately, in the real world, sensing matrices do not always come from random processes. It is therefore desirable to evaluate whether an arbitrary matrix, or frame, is suitable for sensing sparse signals. To this end, the present paper investigates two parameters that measure the coherence of a frame: worst-case and average coherence. We first provide several examples of frames that have small spectral norm, worst-case coherence, and average coherence. Next, we present a new lower bound on worst-case coherence and compare it to the Welch bound. Later, we propose an algorithm that decreases the average coherence of a frame without changing its spectral norm or worst-case coherence. Finally, we use worst-case and average coherence, as opposed to the Restricted Isometry Property, to garner near-optimal probabilistic guarantees on both sparse signal detection and reconstruction in the presence of noise. This contrasts with recent results that only guarantee noiseless signal recovery from arbitrary frames, and which further assume independence across the nonzero entries of the signal—in a sense, requiring small average coherence replaces the need for such an assumption.
Borrowing During Unemployment Unsecured Debt as a Safety Net

This paper examines whether unsecured credit markets help disadvantaged households supplement temporary shortfalls in earnings by investigating how unsecured debt responds to unemployment-induced earnings losses. Results indicate that very low-asset households—those in the bottom decile of total assets—do not borrow in response to these shortfalls. However, other low-asset households do borrow, increasing unsecured debt by more than 11 cents per dollar of earnings lost. In contrast, wealthy households do not increase unsecured debt during unemployment. The evidence suggests that very low-asset households do not have sufficient access to unsecured credit to smooth consumption over transitory unemployment spells.
Formal synthesis of (+/-)-dendrobine: use of the amidofuran cycloaddition/rearrangement sequence.

The formal synthesis of the alkaloid (±)-dendrobine (4) was accomplished using the IMDAF cycloaddition/rearrangement sequence of a furanyl carbamate. Conversion of the rearranged cycloadduct to Kende's advanced intermediate in eight steps completed the formal synthesis of (±)-dendrobine.
Methods for Improving Regression Analysis for Skewed Continuous or Counted Responses

AbstractStandard inference procedures for regression analysis make assumptions that are rarely satisfied in practice. Adjustments must be made to insure the validity of statistical inference. These adjustments, known for many years, are used routinely by some health researchers but not by others. We review some of these methods and give an example of their use in a health services study for a continuous and a count outcome. For the continuous outcome, we describe retransformation using the smear factor, accounting for missing cases via multiple imputation and attrition weights and improving results with bootstrap methods. For the count outcome, we describe zero inflated Poisson and negative binomial models and the two-part model to account for overabundance of zero values. Recent advances in computing and software development have produced user-friendly computer programs that enable the data analyst to improve prediction and inference based on regression analysis.
Improved Infant Swallowing After Gastroesophageal Reflux Disease Treatment: A Function of Improved Laryngeal Sensation?

Objective: The objective of this study was to describe improvements in pediatric swallowing after gastroesophageal reflux treatment. Study Design: The authors conducted a retrospective database and chart review at two tertiary care children's hospitals. Participants: Patients (21 males, 7 females) ranged in age from 1 to 32 months. All patients had clinical evidence of gastroesophageal reflux disease (GERD) as well as evidence of dysphagia with aspiration (laryngeal vestibule and/or trachea) or hypopharyngeal pooling on flexible endoscopic evaluation of swallowing and sensation testing (FEESST) or videofluoroscopic swallow study (VSS). Intervention: Each child underwent either medical or surgical intervention for control of their GERD. Outcome Measures: Outcome measures were change in laryngopharyngeal sensation and swallowing function with repeat swallow evaluation after GERD treatment. Results: A significant improvement in both swallow function and sensory testing was demonstrated after GERD treatment. Conclusions: GERD may result in decreased laryngopharyngeal sensitivity, which may contribute to pediatric swallowing dysfunction. Control of GERD may improve swallow function. These findings have important clinical implications that need further study.
Re-examination of the Mayer Median Voter Model of Trade Policy

This paper examines the empirical validity of the Mayer-Heckscher-Ohlin (M-H-O) model. We test the inequality-tariff relationship studied by Dutt & Mitra (2002) as well as a large country version of Mayer’s model. Dutt and Mitra (2002) found support for the inequality-tariff implication of the model for a cross-section of countries in the 1980s, using physical capital and labor as the two factors in the MH- O model. Our results suggest that this finding is not robust. Instead, we find that when human capital and (unskilled) labor are taken as relevant factors, the Mayer implication is validated in the 1980s. Using cross-sectional country data, we also find that the Mayer implication holds for the 1990s with either physical capital or human capital. We discuss possible explanations for the different findings in the two periods. We extend the model to a large country and obtain tariff levels which are a function of the median voter component and a terms of trade factor. For the 1990s, the positive impact of terms of trade considerations on tariff levels across countries is validated. Using human capital, we find that the median voter component has a negative impact on tariffs in labor-abundant countries and a positive impact in capital-abundant countries.
Polyhedral Potential and Variational Integrator Computation of the Full Two Body Problem

We present a combination of tools which allows for investigation of the coupled orbital and rotational dynamics of two rigid bodies with nearly arbitrary shape and mass distribution, under the influence of their mutual gravitational potential. Methods for calculating that mutual potential and resulting forces and moments for a polyhedral body representation are simple and ecient. Discrete equations of motion, referred to as the Lie Group Variational Integrator (LGVI), preserve the structure of the configuration space, SE(3), as well as the geometric features represented by the total energy and the total angular momentum. The synthesis of these approaches allows us to simulate the full two body problem accurately and eciently. Simulation results are given for two octahedral rigid bodies for comparison with other integration methods and to show the qualities of the results thus obtained. A significant improvement is seen over other integration methods while correctly capturing the interesting eects of strong orbit and attitude dynamics coupling, in multiple scenarios.
Deep-Value Investing, Fundamental Risks, and the Margin of Safety

This article shows a value-oriented investor how to determine the margin of safety that she should demand. In addition to market price volatility, the model identifies three sources of fundamental risk: 1) risk that interim news may necessitate revision of an initial valuation estimate before profits can be taken; 2) uncertainty over the reliability of a value estimate; and 3) uncertainty over when market price will converge to the investor9s value estimate. The model indicates that, while investors should demand margins of safety that are typically 10% to 25% of the share price, larger margins are justified for especially risky stocks.
The Future of Particle Physics as a Natural Science

In the first part of the paper, I give a low-resolution overview of the current state of particle physics — the triumph of the Standard Model and its discontents. I review and re-endorse the remarkably direct and (to me) compelling argument that existing data, properly interpreted, point toward a unified theory of fundamental particle interactions and toward low-energy supersymmetry as the near-term future of high energy physics as a natural science. I then attempt, as requested, some more "visionary" — i.e. even lower resolution — comments about the farther future. In that spirit, I emphasize the continuing importance of condensed matter physics as a source of inspiration and potential application, in particular for expansion of symmetry concepts, and of cosmology as a source of problems, applications, and perhaps ultimately limitations.
A Group-IV Ferromagnetic Semiconductor: MnxGe1−x

We report on the epitaxial growth of a group-IV ferromagnetic semiconductor, Mn(x)Ge(1-x), in which the Curie temperature is found to increase linearly with manganese (Mn) concentration from 25 to 116 kelvin. The p-type semiconducting character and hole-mediated exchange permit control of ferromagnetic order through application of a +/-0.5-volt gate voltage, a value compatible with present microelectronic technology. Total-energy calculations within density-functional theory show that the magnetically ordered phase arises from a long-range ferromagnetic interaction that dominates a short-range antiferromagnetic interaction. Calculated spin interactions and percolation theory predict transition temperatures larger than measured, consistent with the observed suppression of magnetically active Mn atoms and hole concentration.
Sex Differences in Obesity Rates in Poor Countries: Evidence from South Africa

Globally, men and women face markedly different risks of obesity. In all but of handful of (primarily Western European) countries, obesity is much more prevalent among women than men. We examine several potential explanations for this phenomenon. We analyze differences between men and women in reports and effects of potential underlying causes of obesity-childhood and adult poverty, depression, and attitudes about obesity. We evaluate the evidence for each explanation using data collected in an urban African township in the Cape Town metropolitan area. Three factors explain the greater obesity rates we find among women. Women who were nutritionally deprived as children are significantly more likely to be obese as adults, while men who were deprived as children face no greater risk. In addition, women of higher adult socioeconomic status are significantly more likely to be obese, which is not true for men. These two factors - childhood circumstances and adult SES - can fully explain the difference in obesity rates between men and women that we find in our sample. More speculatively, in South Africa, women's perceptions of an 'ideal' female body are larger than men's perceptions of the 'ideal' male body, and individuals with larger 'ideal' body images are significantly more likely to be obese.
Current-source parallel-resonant DC/AC inverter with transformer

This paper gives the theory and experimental results for a current-source parallel-resonant inverter with a transformer used to change voltage levels and provide isolation. The analysis is performed in the frequency domain using Fourier series techniques to predict output power, efficiency, DC-to-AC voltage transfer function, and component voltage and current stresses. The inverter consists of two switches, a large choke inductor, a transformer, and a parallel-resonant circuit. The magnetizing inductance of the transformer is used as the inductance of the parallel-resonant circuit, thereby requiring one less component. Each switch consists of a MOSFET in series with a diode. The MOSFETs have their sources grounded so there is no need for a complicated gate-drive circuit. An inverter was designed and constructed. The DC input voltage was 156 V and the output voltage was a sine wave with a peak value of 224 V at an operating frequency of 50 kHz. The output power at full load was 100 W.
Local multilevel preconditioners for elliptic equations with jump coefficients on bisection grids

The goal of this paper is to design optimal multilevel solvers for the finite element approximation of second order linear elliptic problems with piecewise constant coefficients on bisection grids. Local multigrid and BPX preconditioners are constructed based on local smoothing only at the newest vertices and their immediate neighbors. The analysis of eigenvalue distributions for these local multilevel preconditioned systems shows that there are only a fixed number of eigenvalues which are deteriorated by the large jump. The remaining eigenvalues are bounded uniformly with respect to the coefficients and the meshsize. Therefore, the resulting preconditioned conjugate gradient algorithm will converge with an asymptotic rate independent of the coefficients and logarithmically with respect to the meshsize. As a result, the overall computational complexity is nearly optimal.
Agreeable People Like Agreeable Virtual Humans

This study explored associations between the five-factor personality traits of human subjects and their feelings of rapport when they interacted with a virtual agent or real humans. The agent, the Rapport Agent, responded to real human speakers' storytelling behavior, using only nonverbal contingent (i.e., timely) feedback. We further investigated how interactants' personalities were related to the three components of rapport: positivity, attentiveness, and coordination. The results revealed that more agreeable people showed strong self-reported rapport and weak behavioral-measured rapport in the disfluency dimension when they interacted with the Rapport Agent, while showing no significant associations between agreeableness and self-reported rapport, nor between agreeableness and the disfluency dimension when they interacted with real humans. The conclusions provide fundamental data to further develop a rapport theory that would contribute to evaluating and enhancing the interactional fidelity of an agent on the design of virtual humans for social skills training and therapy.
Price Formation in Double Auctions

We develop a model of information processing and strategy choice for participants in a double auction. Sellers in this model form beliefs that an offer will be accepted by some buyer. Similarly, buyers form beliefs that a bid will be accepted. These beliefs are formed on the basis of observed market data, including frequencies of asks, bids, accepted asks, and accepted bids. Then traders choose an action that maximizes their own expected surplus. The trading activity resulting from these beliefs and strategies is suffcient to achieve transaction prices at competitive equilibrium and complete market effciency after several periods of trading.
Uniqueness in symmetric first-price auctions with affiliation

Abstract The first-price auction has a unique monotone pure strategy equilibrium when there are n symmetric risk-averse bidders having affiliated types and interdependent values.
Observational signatures and non-Gaussianities of general single-field inflation

We perform a general study of primordial scalar non-Gaussianities in single field inflationary models. We consider models where the inflaton Lagrangian is an arbitrary function of the scalar field and its first derivative, and the sound speed is arbitrary. We find that under reasonable assumptions, the non-Gaussianity is completely determined by 5 parameters. In special limits of the parameter space, one finds distinctive ''shapes'' of the non-Gaussianity. In models with a small sound speed, several of these shapes would become potentially observable in the near future. Different limits of our formulae recover various previously known results.
Facile allylboration of ketones with β-benzyloxy-γ,γ-difluoroallylboronate: Preparation of gem-difluorinated homoallylic tert-alcohols

Abstract The reaction of β-benzyloxy-γ,γ-difluoroallylboronate, at room temperature and in the absence of catalysts, with a variety of aromatic and aliphatic ketones of varying sterics and electronic requirements furnishes fluorinated homoallylic tert-alcohols in 62–82% yields. Representatives of these alcohols were converted to their corresponding α,α-difluoro-β-hydroxy ketones in 73–85% yields.
Composite quadratic Lyapunov functions for constrained control systems

A Lyapunov function based on a set of quadratic functions is introduced in this paper. We call this Lyapunov function a composite quadratic function. Some important properties of this Lyapunov function are revealed. We show that this function is continuously differentiable and its level set is the convex hull of a set of ellipsoids. These results are used to study the set invariance properties of continuous-time linear systems with input and state constraints. We show that, for a system under a given saturated linear feedback, the convex hull of a set of invariant ellipsoids is also invariant. If each ellipsoid in a set can be made invariant with a bounded control of the saturating actuators, then their convex hull can also be made invariant by the same actuators. For a set of ellipsoids, each invariant under a separate saturated linear feedback, we also present a method for constructing a nonlinear continuous feedback law which makes their convex hull invariant.