cssi/SciSciGPT-SciSciNet huggingface dataset:
Deep Inelastic Scattering and Small-x Physics

This is a slightly extended version of lectures given in Cargese in August, 1994. The first part reviews the parton model and operator product expansions of deep inelastic lepton-nucleon scattering. While the discussion is self-contained it may seem, perhaps, a bit rushed. There are many more leisurely expositions of this material available in standard textbooks for the reader who finds the present discussion somewhat brief. The second part gives a general discussion of small-α behavior with an emphasis on a qualitative understanding of small-x behavior. Achieving high densities of spatially overlapping partons, and how this occurs in the BFKL pomeron, is the focal point of the discussion. The third part gives a more technical treatment of the BFKL pomeron and how it may be possible to measure it.
Multiparty Communication Complexity and Threshold Circuit Size of AC^0

We prove an n^Omega(1)/4^k lower bound on the randomized k-party communication complexity of depth 4 AC^0 functions in the number-on-forehead (NOF) model for up to Theta(log n) players. These are the first non-trivial lower bounds for general NOF multiparty communication complexity for any AC^0 function for omega(log log n) players. For non-constant k the bounds are larger than all previous lower bounds for any AC^0 function even for simultaneous communication complexity. Our lower bounds imply the first super polynomial lower bounds for the simulation of AC^0 by MAJ-SYMM-AND circuits, showing that the well-known quasipolynomial simulations of AC^0 by such circuits are qualitatively optimal, even for formulas of small constant depth. We also exhibit a depth 5 formula in NPc-BPPc for up to Theta(log n) players and derive an Omega(2^{sqrt{log n}/sqrt{k}}) lower bound on the randomized k-party NOF communication complexity of set disjointness for up to Theta(log^{1/3} n) players which is significantly larger than the O(log log n) players allowed in the best previous lower bounds for multiparty set disjointness. We prove other strong results for depth 3 and 4 AC^0 functions.
Incremental bus service design: combining limited-stop and local bus services

Long in-vehicle travel times resulting from frequent stops make bus service an unattractive choice for many commuters. Limited-stop bus services however have the advantage of shorter in-vehicle times experienced by passengers. In this work, we seek to modify a given bus service by optimally reassigning some number of bus trips, as opposed to providing additional trips, to operate a limited-stop service. We propose an optimization model to determine a limited-stop service route to be operated in parallel with the local service and its associated frequency to maximize total user welfare. A few theoretical properties of the model are established and used to develop a solution approach. As a proof of concept, we present numerical results obtained using real-world data together with comprehensive discussions of solution quality, computational times and the model’s sensitivity to different parameters. Finally, we solve the optimization model for 178 real-world bus routes with different characteristics in order to demonstrate the impacts of some key attributes on potential benefits of limited-stop services.
Generation of mouse models of myeloid malignancy with combinatorial genetic lesions using CRISPR-Cas9 genome editing

Genome sequencing studies have shown that human malignancies often bear mutations in four or more driver genes, but it is difficult to recapitulate this degree of genetic complexity in mouse models using conventional breeding. Here we use the CRISPR-Cas9 system of genome editing to overcome this limitation. By delivering combinations of small guide RNAs (sgRNAs) and Cas9 with a lentiviral vector, we modified up to five genes in a single mouse hematopoietic stem cell (HSC), leading to clonal outgrowth and myeloid malignancy. We thereby generated models of acute myeloid leukemia (AML) with cooperating mutations in genes encoding epigenetic modifiers, transcription factors and mediators of cytokine signaling, recapitulating the combinations of mutations observed in patients. Our results suggest that lentivirus-delivered sgRNA:Cas9 genome editing should be useful to engineer a broad array of in vivo cancer models that better reflect the complexity of human disease.
Receptor Tyrosine Kinases Fall into Distinct Classes Based on Their Inferred Signaling Networks

Although many anticancer drugs that target receptor tyrosine kinases (RTKs) provide clinical benefit, their long-term use is limited by resistance that is often attributed to increased abundance or activation of another RTK that compensates for the inhibited receptor. To uncover common and unique features in the signaling networks of RTKs, we measured time-dependent signaling in six isogenic cell lines, each expressing a different RTK as downstream proteins were systematically perturbed by RNA interference. Network models inferred from the data revealed a conserved set of signaling pathways and RTK-specific features that grouped the RTKs into three distinct classes: (i) an EGFR/FGFR1/c-Met class constituting epidermal growth factor receptor, fibroblast growth factor receptor 1, and the hepatocyte growth factor receptor c-Met; (ii) an IGF-1R/NTRK2 class constituting insulin-like growth factor 1 receptor and neurotrophic tyrosine receptor kinase 2; and (iii) a PDGFRβ class constituting platelet-derived growth factor receptor β. Analysis of cancer cell line data showed that many RTKs of the same class were coexpressed and that increased abundance of an RTK or its cognate ligand frequently correlated with resistance to a drug targeting another RTK of the same class. In contrast, abundance of an RTK or ligand of one class generally did not affect sensitivity to a drug targeting an RTK of a different class. Thus, classifying RTKs by their inferred networks and then therapeutically targeting multiple receptors within a class may delay or prevent the onset of resistance.
The Importance of Moral Construal: Moral versus Non-Moral Construal Elicits Faster, More Extreme, Universal Evaluations of the Same Actions

Over the past decade, intuitionist models of morality have challenged the view that moral reasoning is the sole or even primary means by which moral judgments are made. Rather, intuitionist models posit that certain situations automatically elicit moral intuitions, which guide moral judgments. We present three experiments showing that evaluations are also susceptible to the influence of moral versus non-moral construal. We had participants make moral evaluations (rating whether actions were morally good or bad) or non-moral evaluations (rating whether actions were pragmatically or hedonically good or bad) of a wide variety of actions. As predicted, moral evaluations were faster, more extreme, and more strongly associated with universal prescriptions—the belief that absolutely nobody or everybody should engage in an action—than non-moral (pragmatic or hedonic) evaluations of the same actions. Further, we show that people are capable of flexibly shifting from moral to non-moral evaluations on a trial-by-trial basis. Taken together, these experiments provide evidence that moral versus non-moral construal has an important influence on evaluation and suggests that effects of construal are highly flexible. We discuss the implications of these experiments for models of moral judgment and decision-making.
Improved inapproximability results for counting independent sets in the hard-core model

We study the computational complexity of approximately counting the number of independent sets of a graph with maximum degree Δ. More generally, for an input graph G=V,E and an activity λ>0, we are interested in the quantity ZGλ defined as the sum over independent sets I weighted as wI=λ|I|. In statistical physics, ZGλ is the partition function for the hard-core model, which is an idealized model of a gas where the particles have non-negligible size. Recently, an interesting phase transition was shown to occur for the complexity of approximating the partition function. Weitz showed an FPAS for the partition function for any graph of maximum degree Δ when Δ is constant and λ 0. We remove the upper bound in the assumptions of Sly's result for Δi¾?4,5, that is, we show that there does not exist efficient randomized approximation algorithms for all λ>λcTΔ for Δ=3 and Δi¾?6. Sly's inapproximability result uses a clever reduction, combined with a second-moment analysis of Mossel, Weitz and Wormald which prove torpid mixing of the Glauber dynamics for sampling from the associated Gibbs distribution on almost every regular graph of degree Δ for the same range of λ as in Sly's result. We extend Sly's result by improving upon the technical work of Mossel et al., via a more detailed analysis of independent sets in random regular graphs. © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 45, 78-110, 2014
TWO PLUS TWO DOES NOT EQUAL THREE: STATISTICAL TESTS FOR MULTIPLE GENOME COMPARISON

Gene clusters that span three or more chromosomal regions are of increasing importance, yet statistical tests to validate such clusters are in their infancy. Current approaches either conduct several pairwise comparisons or consider only the number of genes that occur in all of the regions. In this paper, we provide statistical tests for clusters spanning exactly three regions based on genome models of typical comparative genomics problems, including analysis of conserved linkage within multiple species and identification of large-scale duplications. Our tests are the first to combine evidence from genes shared among all three regions and genes shared between pairs of regions. We show that our tests of clusters spanning three regions are more sensitive than existing approaches, and can thus be used to identify more diverged homologous regions.
Superfluid LDA (SLDA): Local Density Approximation for Systems with Superfluid Correlations

We present a concise account of our development of the first genuine Local Density Approximation (LDA) to the Energy Density Functional (EDF) for fermionic systems with superfluid correlations, with a particular emphasis to nuclear systems.
Divestiture Structure and Tax Attributes: Evidence from the Omnibus Budget Reconciliation Act of 1993

Using data from 1991 through 1994, this study investigates the effect of tax provisions on divestiture structure. Specifically, a set of taxable asset and taxable stock sell‐offs are analyzed to assess the impact of a tax‐law change requiring purchased intangibles to be amortized over 15 years on the structure of these divestitures. The results provide evidence that allowing the amortization of goodwill, a previously nondeductible intangible asset, increases the likelihood of step‐up (goodwillcreating) divestitures. However, the likelihood of step‐up transactions decreases as a function of the level of other transaction intangibles such as customer lists. Although the incidence of step‐up transactions does not increase after the passage of the tax law, the results show that the structure of individual transactions is affected in an offsetting manner as a function of goodwill and other transaction intangibles. This study also provides evidence suggesting that inferences vary depending on how transactions a...
Tracking Controllers for Robot Manipulators: A High Gain Perspective

In this paper we propose a controller for the path tracking problem of robotic manipulators. The proposed controller structure is very similar to that of the "computed-torque" scheme widely known in the literature. However, unlike the "computed-torque" scheme this controller is robust with respect to parameter uncertainty and disturbances. The robustness is provided by a high gain mechanism that works in conjunction with a nonlinear precompensator in the control loop. The fundamental action of the high gain is to minimize the effective uncertainty that remains, subsequent to any cancellation by the precompensator. The synthesis of this controller is quite easily formulated and its performance is dictated primarily by a single high-gain parameter, thus making it particularly attractive for on line tuning. Some guidelines are provided for the off-line selection of this high-gain parameter.
Standard model with compactified spatial dimensions

We analyze the structure of the standard model coupled to gravity with spatial dimensions compactified on a three-torus. We find that there are no stable one-dimensional vacua at zero temperature, although there does exist an unstable vacuum for a particular set of Dirac neutrino masses.
Plate Size and Color Suggestibility: The Delboeuf Illusion’s Bias on Serving and Eating Behavior

Despite the challenged contention that consumers serve more onto larger dinnerware, it remains unclear what would cause this and who might be most at risk. The results of five studies suggest that the neglected Delboeuf illusion may explain how the size of dinnerware creates two opposing biases that lead people to overserve on larger plates and bowls and underserve on smaller ones. A countercyclical sinus-shaped relationship is shown to exist between these serving biases and the relative gap between the edge of the food and the edge of the dinnerware. Although these serving biases are difficult to eliminate with attention and education, changing the color of one’s dinnerware or tablecloth may help attenuate them. By showing that the Delboeuf illusion offers a mechanistic explanation for how dinnerware size can bias serving and intake, we open new theoretical opportunities for linking illusions to eating behavior and suggest how simple changes in design can improve consumer welfare.
Near-wall similarity in a pressure-driven three-dimensional turbulent boundary layer

Mean velocity, measured wall pressure and wall shear stress fields were made in a three dimensional pressure-driven turbulent boundary layer created by a cylinder with trailing edge placed normal to a flat plate floor. The direct force wall shear stress measurements were made with floating element direct force sensing shear meter that responded to both the magnitude and direction of the local wall shear stress. The ability of 10 near wall similarity models to describe the near wall velocity field for the measured flow under a wide range of skewing conditions and a variety of pressure gradient and wall shear vector orientations was used.
Short-term load forecasting using optimized neural network with genetic algorithm

An optimized neural network modeling approach with genetic algorithm for short-term load forecasting based on only multiple delayed historical power load data is proposed. Genetic algorithm is used to globally optimize the number of delayed input neurons and the number of neurons in the hidden layer of the neural network architecture. Modification of Levenberg-Marquardt algorithm with Bayesian regularization is used to improve the generalization ability of the neural network. The performance of our proposed approach has been compared using actual power load data sets. Numerical results show that our proposed power load forecasting approach is comparable to the existing approaches that use multiple input variables such as power load data, day type load patterns and weather conditions
Layout of multiple views for volume visualization: a user study

Volume visualizations can have drastically different appearances when viewed using a variety of transfer functions. A problem then occurs in trying to organize many different views on one screen. We conducted a user study of four layout techniques for these multiple views. We timed participants as they separated different aspects of volume data for both time-invariant and time-variant data using one of four different layout schemes. The layout technique had no impact on performance when used with time-invariant data. With time-variant data, however, the multiple view layouts all resulted in better times than did a single view interface. Surprisingly, different layout techniques for multiple views resulted in no noticeable difference in user performance. In this paper, we describe our study and present the results, which could be used in the design of future volume visualization software to improve the productivity of the scientists who use it.
Formal synthesis of (±)-platensimycin

A formal total synthesis of (±)-platensimycin [(±)-1] is reported involving an intramolecular Stetter reaction and a radical cyclization.
The Quest For Extra‐Large Pore, Crystalline Molecular Sieves

The definition and reasons for desiring extralarge pore, crystalline molecular sieves are ennumerated. A historical perspective on the development of these materials is presented with emphasis on critical features important for practical application. Based on the known physiochemical properties of extra-large pore materials, several avenues for their synthesis are suggested. Finally, a few issues of concern when dealing with this class of materials are presented.
The Kansas case of K.M.H. US law concerning the legal status of known sperm donors

This article examines the Kansas Supreme Court case of K.M.H. , 169 P.3d 1025 (Kan. 2007) within the context of an increasing body of US case law that addresses the legal status of known sperm donors vis-a-vis their biological children born to women who are not in heterosexual marriages. The article begins with an explanation of US parentage law and then reviews and synthesizes the cases leading up to the K.M.H. decision. The article then details the four different opinions in the K.M.H. case, and, in particular, lays out the discussion of the constitutional challenges to the Kansas sperm donor statute. Next the article discusses how the previous known sperm donor cases impacted the sperm donor’s arguments in K.M.H. , and how these cases failed to support his claim for parental rights. The article continues with a review of two more decisions, issued after the K.M.H. case, incorporating these cases into the evolving trends discerned in the recent court decisions. The article concludes by summarizing K.M.H. ’s position within that evolution.
Toe Walking and Language Development

Neurodevelopmental markers that are present early in childhood may identify children at risk for later developmental disabilities. This paper attempts to clarify the relationship between one such proposed marker, toe walking, and language development in a general pediatric population. One hundred sixty-three children being seen for well-child visits were included in the study. Information from each child's caretaker was obtained for language development and a history of toe walking; observation of toe walking during the visit was also included. The frequency of toe walking was 24%. Language quotients were calculated and compared for toe walkers (n = 39) and non-toe walkers (n = 127). The mean language quotient for toe walkers tended to be consistently lower than that for non-toe walkers. The specificity of toe walking for low language scores was 85% but had a sensitivity of only 32%. Although an association between toe walking and language delay is supported by the present data, the association does not appear to be clinically significant.
Learning Parse and Translation Decisions from Examples with Rich Context

We present a knowledge and context-based system for parsing and translating natural language and evaluate it on sentences from the Wall Street Journal. Applying machine learning techniques, the system uses parse action examples acquired under supervision to generate a deterministic shift-reduce parser in the form of a decision structure. It relies heavily on context, as encoded in features which describe the morphological, syntactic, semantic and other aspects of a given parse state.
An Improved Procedure for the Large Scale Preparation of 2-Chloro-4,6-dimethoxy-1,3,5-triazine

Abstract A robust process for the preparation of multikilogram quantities of 2-chloro-4,6-dimethoxy-1,3,5-triazine (1) is described.
Highly polydentate ligands. Part 4. Crystal structures of neodymium(III) and erbium(III) complexes of 3,12-bis(carboxymethyl)-6,9-dioxa-3,12-diazatetradecanedioate(4–)

The structures of calcium salts of the erbium(III) and neodymium(III) chelates of the calcium-selective octadentate ligand egta4–[H4egta = 3,12-bis(carboxymethyl)-6,9-dioxa-3,12-diazatetradecanedioic acid] have been determined, in order to identify the structural changes that occur in a calcium-selective binding site when lanthanides are substituted for calcium. Ca[Er(egta)(OH2)]2·12H2O·(CH3)2CO (1) crystallizes in the monoclinic space group P21(Z= 2), with a= 12.710(2), b= 12.157(2), c= 17.765(3)A, and β= 105.79(1)°R= 0.027, R′= 0.035. Ca[Nd(egta)(OH2)]2·9H2O (2) crystallizes in the monoclinic space group P21/c(Z= 2), with a= 10.776(2), b= 18.218(4), c= 12.560(2)A, and β= 112.14(1)°; R= 0.028, R′= 0.040. The full octadentate chelating capability of egta4– is utilized in both chelates. In contrast to the eight-co-ordinate calcium ions in [Ca(egta)]2–, the ErIII ions in (1) are nine-co-ordinate; the ninth co-ordination site is occupied by a water molecule. Of the three ligand atom types, the carboxylate oxygen atoms are bound at the shortest distance [Er–O(carboxylate)av= 2.31(3)A], followed by the ether oxygen atoms [Er–O(ether)av= 2.42(5)A], and the amine nitrogen atoms [Er–Nav= 2.57(4)A]. The NdIII ions in (2) are ten-co-ordinate; ten-co-ordination is achieved in the solid state by binding a water molecule, as well as a carboxylate oxygen atom from an adjacent complex ion The order of metal–Iigand bond distances observed for NdIII is the same as that observed for ErIII Nd–O(carboxylate)av= 2.46(1), Nd–O(ether)av= 2.67(3), Nd–Nav= 2.81(7)A.
do more transparent government govern better

Islam explores the link between information flows and governance or institutional quality. Economic theory expounds on the importance of information on economic outcomes either through its direct effect on prices and quantities or through its effect on other factors such as institutions and the quality of governance. She shows that countries with better information flows also govern better. Two kinds of indicators are used to assess better information flows. One index is based on the existence of freedom of information laws. A second index called the "transparency" index measures the frequency with which economic data are published in countries around the world. Empirical analysis shows that countries which have better information flows as measured by both indicators have better quality governance. This paper - a product of the Poverty Reduction and Economic Management Division, World Bank Institute - is part of a larger effort in the institute to disseminate its work on institutions and governance.
Light-Induced Indeterminacy Alters Shade-Avoiding Tomato Leaf Morphology

Plants sense the foliar shade of competitors and alter their developmental programs through the shade-avoidance response. Internode and petiole elongation, and changes in overall leaf area and leaf mass per area, are the stereotypical architectural responses to foliar shade in the shoot. However, changes in leaf shape and complexity in response to shade remain incompletely, and qualitatively, described. Using a meta-analysis of more than 18,000 previously published leaflet outlines, we demonstrate that shade avoidance alters leaf shape in domesticated tomato (Solanum lycopersicum) and wild relatives. The effects of shade avoidance on leaf shape are subtle with respect to individual traits but are combinatorially strong. We then seek to describe the developmental origins of shade-induced changes in leaf shape by swapping plants between light treatments. Leaf size is light responsive late into development, but patterning events, such as stomatal index, are irrevocably specified earlier. Observing that shade induces increases in shoot apical meristem size, we then describe gene expression changes in early leaf primordia and the meristem using laser microdissection. We find that in leaf primordia, shade avoidance is not mediated through canonical pathways described in mature organs but rather through the expression of KNOTTED1-LIKE HOMEOBOX and other indeterminacy genes, altering known developmental pathways responsible for patterning leaf shape. We also demonstrate that shade-induced changes in leaf primordium gene expression largely do not overlap with those found in successively initiated leaf primordia, providing evidence against classic hypotheses that shaded leaf morphology results from the prolonged production of juvenile leaf types.
Helical chirality in donor-acceptor catenanes.

A [2]catenane in which the macrocyclic polyether, bisparaphenylene[34]crown-10, is interlocked with the tetracationic cyclophane, cyclobis(paraquat-p-phenylene), is shown by dynamic 1H NMR spectroscopy, using (i) neutral and (ii) anionic chiral shift reagents (CSRs), to exist at low temperatures (197 K) in acetone-d6 solutions as 1:1 and 2:1 mixtures of diastereoisomeric complexes and salts, respectively, as a consequence of the helical chirality associated with the [2]catenane interacting with the CSRs.
New azolidinediones as inhibitors of protein tyrosine phosphatase 1B with antihyperglycemic properties.

Insulin resistance in the liver and peripheral tissues together with a pancreatic cell defect are the common causes of type 2 diabetes. It is now appreciated that insulin resistance can result from a defect in the insulin receptor signaling system, at a site post binding of insulin to its receptor. Protein tyrosine phosphatases (PTPases) have been shown to be negative regulators of the insulin receptor. Inhibiton of PTPases may be an effective method in the treatment of type 2 diabetes. A series of azolidinediones has been prepared as protein tyrosine phosphatase 1B (PTP1B) inhibitors. Several compounds were potent inhibitors against the recombinant rat and human PTP1B enzymes with submicromolar IC50 values. Elongated spacers between the azolidinedione moiety and the central aromatic portion of the molecule as well as hydrophobic groups at the vicinity of this aromatic region were very important to the inhibitory activity. Oxadiazolidinediones 87 and 88 and the corresponding acetic acid analogues 119 and ...
Two populations of metal-free stars in the early Universe

We construct star formation histories at redshifts z? 5 for two physically distinct populations of primordial, metal-free stars, motivated by theoretical and observational arguments that have hinted towards the existence of an intermediate stellar generation between Population III and Population I/II. Taking into account the cosmological parameters as recently revised by the Wilkinson Microwave Anisotropy Probe after three years of operation, we determine self-consistent reionization histories and discuss the resulting chemical enrichment from these early stellar generations. We find that the bulk of ionizing photons and heavy elements produced at high redshifts must have originated in Population II.5 stars, which formed out of primordial gas in haloes with virial temperatures?10 4 K, and had typical masses?10M ⊙ . Classical Population III stars, formed in minihaloes and having masses?100 M ⊙ , on the other hand, had only a minor impact on reionization and early metal enrichment. Specifically, we conclude that only ≃ 10 per cent by mass of metal-free star formation went into Population III.
Estimation of Extreme Values and Associated Level Sets of a Regression Function via Selective Sampling

We propose a new method for estimating the locations and the value of an absolute maximum (minimum) of a function from the observations contaminated by random noise. Our goal is to solve the problem under minimal regularity and shape constraints. In particular, we do not assume dierentiability of a function nor that its maximum is attained at a single point. We provide tight upper and lower bounds for the performance of proposed estimators. Our method is adaptive with respect to the unknown parameters of the problem over a large class of underlying distributions.
A method for PID controller tuning using nonlinear control techniques

In this work, we propose a two-level, optimization-based method for deriving tuning guidelines for proportional-integral-derivative (PID) controllers that take explicitly into account the presence of nonlinear behavior. The central idea behind the proposed method is the selection of the PID controller tuning parameters so as to best "emulate" the control action and closed-loop response under a given nonlinear controller for a broad set of initial conditions and set-point changes. The first level involves using classical tuning guidelines (typically derived on the basis of linear approximations, running open or closed-loop tests) to obtain reasonable bounds on the tuning parameters in order to satisfy various design criteria such as stability, performance and robustness. These bounds are in turn incorporated as constraints on the optimization problem solved at the higher level to yield tuning parameter values that improve upon the values obtained from the first level to better emulate the closed-loop behavior under the nonlinear controller. The efficacy of the proposed tuning method is demonstrated through application to a nonlinear chemical reactor example.
Vibration characteristics of hexagonal radial rib and hoop platforms

Experiment and analysis have been used to characterize the modes of vibration of planar radial rib and hoop hexagonal platforms. Finite element analysis correlated very well with experimental results. The sensitivity of mode shapes and frequencies to cable stiffness and initial tension is presented. Threshold values have been identified, above which changes in cable stiffness do not affect the first few platform vibration modes. Primary vibration modes of the radial rib platform involve beam bending. Vibration modes of the hoop platform exhibit both beam bending and frame bending and torsion. Results indicate for low order polygonal structures, the radial rib concept produced a higher fundamental frequency. For high order polygonal structures, the hoop concept has the potential to achieve a higher fundamental frequency than the radial rib concept.
Oxidation-resistant, sterically demanding phenanthrolines as supporting ligands for copper(I) nitrene transfer catalysts.

New 1,10-phenanthroline ligands have been synthesized with C6F5– or 2,4,6-(CF3)3C6H2– groups in the 2- and 9-positions; a cationic copper(I) complex of the latter catalyses nitrene transfer to the C–H bonds of electron-rich arenes.
Error-correcting two-dimensional modulation codes

Modulation coding, to limit the number of consecutive zeros in a data stream, is essential in digital magnetic recording/playback systems. Additionally, such systems require error-correction coding to ensure that the decoded output matches the recorder input, even if noise is present. Typically, these two coding steps have been performed independently, although various methods of combining them into one step have recently appeared. Another recent development is two-dimensional modulation codes, which meet runlength constraints using several parallel recording tracks, significantly increasing channel capacity. The article combines these two ideas. Previous techniques (both block and trellis structures) for combining error correction and modulation coding are surveyed, with discussion of their applicability in the two-dimensional case. One approach, based on trellis-coded modulation, is explored in detail, and a class of codes is developed which exploits the increased capacity to achieve good error-correcting ability at the same rate as common non-error-correcting one-dimensional codes. >
ANTHROPOLOGY AND AFRO‐AMERICAN STUDIES

subject of study for cultural anthropologists, and Africa has been for many years one of the favorite locations for ethnographic fieldwork, yet undergraduate students today seeking relevant information in the area they refer to as "Black studies" are not likely to consider anthropology as one of their most valuable sources. Because historians and sociologists have played an active role in cstablishing Afro-American studies programs in liberal arts college curriculums, they are apt to be seen by their students as better informed and more concerned in this
Synthesis of self-organizing mesogenic materials containing a sulfur-based five-membered heterocyclic core.

The majority of low molar mass calamitic mesogenic systems in the literature contain linear cores based on the 1,4-disubstituted phenyl ring. Heterocyclic cores such as thiophene impart unique physical properties as their slightly bent structure leads to features including a reduced packing ability (generally giving rise to lower melting points than their phenyl counterparts), a medium to strong lateral dipole, high anisotropy of the polarizability, low viscosity etc. This critical review describes the most recent synthetic methodology that has been used to prepare thiophene, 1,3-thiazole, and 1,3,4-thiadiazole-based mesogenic materials. (154 references)
Variationally universal hashing

The strongest well-known measure for the quality of a universal hash-function family H is its being e-strongly universal, which measures, for randomly chosen h ∈ H, one's inability to guess h(m') even if h(m) is known for some m ≠ m' We give example applications in which this measure is too weak, and we introduce a stronger measure for the quality of a hash-function family, e-variationally universal, which measures one's inability to distinguish h(m') from a random value even if h(m) is known for some m ≠ m'. We explain the utility of this notion and provide an approach for constructing efficiently compu table e-VU hash-function families.
An intelligent power supply conditioning system using an embedded microcontroller

Uninterruptible power supplies present a method to quickly detect a loss of power and replace the defective power source before any damage or corruption occurs. Using an inverter circuit to generate a square wave for a DC source can supply a crude approximation of an AC wave form. Obviously, the harmonic content is high and voltage regulation and current limiting are essentially non-existent. The microcontroller brings complex timing functions to the design equation. Also, the microcontroller can dynamically adjust the wave forms for both voltage and current regulation. Because of the speed of the microcontroller and its ability to determine when errant conditions on the incoming power line occur, a UPS can be constructed that can switch reliable, temporary power onto the electrical load before any devastating effects occur.
Thermodynamic perturbation theory for self-assembling mixtures of divalent single patch colloids

In this work we extend Wertheim's thermodynamic perturbation theory (TPT) to binary mixtures (species A and species B) of patchy colloids were each species has a single patch which can bond a maximum of twice (divalent). Colloids are treated as hard spheres with a directional conical association site. We restrict the system such that only patches between unlike species share attractions; meaning there are AB attractions but no AA or BB attractions. The theory is derived in Wertheim's two density formalism for one site associating fluids. Since the patches are doubly bondable, associated chains, of all chain lengths, as well as 4-mer rings consisting of two species A and two species B colloids are accounted for. With the restriction of only AB attractions, triatomic rings of doubly bonded colloids, which dominate in the corresponding pure component case, cannot form. The theory is shown to be in good agreement with Monte Carlo simulation data for the structure and thermodynamics of these patchy colloid mixtures as a function of temperature, density, patch size and composition. It is shown that 4-mer rings dominate at low temperature, inhibiting the polymerization of the mixture into long chains. Mixtures of this type have been recently synthesized by researchers. This work provides the first theory capable of accurately modeling these mixtures.
Supporting self-expression for informal communication

Mobile phones are becoming the central tools for communicating and can help us keep in touch with friends and family on-the-go. However, they can also place high demands on attention and constrain interaction. My research concerns how to design communication mechanisms that mitigate these problems to support self-expression for informal communication on mobile phones. I will study how people communicate with camera-phone photos, paper-based sketches, and projected information and how this communication impacts social practices.
Current Issues in Discrete Choice Modeling

Until recently, computational constraints forced researchers in thediscrete choice area to limit themselves to very simple statistical models,such as the multinomial logit (MNL), in which choice probabilities could beevaluated quickly on a computer. But the MNL only makes sense as abehavioral model under very special circumstances. Recent advances incomputation make it possible to estimate richer behavioral models thatgenerate very complex choice probability expressions. This paper discusses anumber of possible avenues for future research in the discrete choice areain light of these developments.
Latin American Agriculture in a World of Trade Agreements

Latin American and Caribbean (LAC) countries are members of 29 distinct free trade agreements with other Latin American partners, and 44 such agreements exist between an LAC country and other countries. Among the LAC countries linked by an Free Trade Agreement (FTA), a large percentage of trade is already duty free though many trade barriers in agriculture persist. There is a significant difference in the trade patterns among the LAC countries. The Southern Cone countries, for example, have extensive agricultural exports to Asia and to the European Union (EU), and have few FTAs with regional countries. By contrast, countries in Central America and the Andean region have extensive trade agreements with each other, and have fewer exports outside the region. Meanwhile, other regions are negotiating ambitious mega‐agreements, particularly the Trans Pacific Partnership (TPP) and the Trans‐Atlantic Trade and Investment Partnership (T‐TIP). These could have significant impacts on the region, including trade diversion and preference erosion in major import markets. Several possible avenues exist for Latin American countries to accomplish the following: counter the impact of a TPP and T‐TIP on agricultural exports; strengthen existing bilateral trade agreements within the region; link existing multi‐country agreements such as Mercado Comun del Sur (MERCOSUR) and the Pacific Alliance to North American Free Trade Agreement (NAFTA); consolidate the current trade agreements with the EU; or “sign on” to the TPP. This last option would be more attractive if China were to become a TPP participant. If China is not interested in joining the TPP, then for some countries a direct FTA with China could be contemplated.
On path selection in combinational logic circuits

In order to ascertain correct operation of digital logic circuits it is necessary to verify correct functional operation as well as correct operation at desired clock rates. To ascertain correct operation at desired clock rates, it is verified that signal propagation delays along a set of selected paths fall within allowed limits by applying appropriate stimuli. It has previously been suggested that an appropriate set of paths to test would be the one that includes at least one path, with maximum modeled delay, for each circuit lead or gate input. Here, algorithms to select such sets of paths with minimum cardinality are given. >
Incoherent charge transport through molecular wires: interplay of Coulomb interaction and wire population

The influence of Coulomb interaction on the electron transport through molecular wires is studied in the regime of incoherent tunneling. In the limit of strong Coulomb repulsion, the current for spinless electrons is determined. It is shown that the voltage profile along the wire crucially influences the dependence of the current on the wire length. Upon inclusion of the spin degree of freedom one finds a blocking effect which depends both on the interaction strength and on the population of the wire. For finite Coulomb interaction, the temperature dependence of the blocking is studied and it is shown that several regimes with different blocking strength may exist.
Fast stereoscopic images with ray-traced volume rendering

One of the drawbacks of standard volume rendering techniques is that is it often difficult to comprehend the three-dimensional structure of the volume from a single frame; this is especially true in cases where there is no solid surface. Generally, several frames must be generated and viewed sequentially, using motion parallax to relay depth. Another option is to generate a single spectroscopic pair, resulting in clear and unambiguous depth information in both static and moving images. Methods have been developed which take advantage of the coherence between the two halves of a stereo pair for polygon rendering and ray-tracing, generating the second half of the pair in significantly less time than that required to completely render a single image. This paper reports the results of implementing these techniques with parallel ray-traced volume rendering. In tests with different data types, the time savings is in the range of 70--80%.
Traits of patients who screen positive for dementia and refuse diagnostic assessment.

Background As part of the debate about screening for dementia, it is critical to understand why patients agree or disagree to diagnostic assessment after a positive screening test. We used the Perceptions Regarding Investigational Screening for Memory in Primary Care (PRISM-PC) questionnaire to measure the characteristics of patients who screened positive for dementia but refused further diagnostic assessment.
Particle-in-Cell Simulations of the Lasertron

The lasertron is a device (either rf or dc) for producing intense, very short, pulsed electron beams (tens of picoseconds). In the dc lasertron, a laser is pulsed repetitively onto a photoemissive cathode. In general, the current is not space-charge limited and follows the laser intensity. The electron pulse is then accelerated out of the device by a constant voltage. By using the laser the need for a subharmonic buncher is eliminated. In the rf lasertron, the diode becomes an rf cavity. This improves the breakdown characteristics of the device, allowing higher voltages to be applied and hence higher currents to be obtained. The calculations are aimed at producing a 10 nC electron beam with an emittance of less than 40..pi.. mm-mrad for use in free-electron laser experiments at Los Alamos. Other applications of the lasertron include efficient microwave or rf generation. A class of electrode shapes has been obtained which in the absence of space charge produces no emittance growth. These shapes have been studied with the particle-in-cell simulation model ISIS, and the electrodes which produce minimum emittance including the effect of space charge have been determined. Unique emittance problems associated with the time dependence of the beam pulsemore » are studied and conditions for reducing these effects are discussed. 5 refs., 5 figs.« less
Considering the Future: The Conceptualization and Measurement of Elaboration on Potential Outcomes

We examine a new construct dealing with individuals' tendency to elaborate on potential outcomes, that is, to generate and evaluate potential positive and negative consequences of their behaviors. We develop the elaboration on potential outcomes (EPO) scale and then investigate its relationships with conceptually related traits and its association with consumer behaviors such as exercise of self-control, procrastination, compulsive buying, credit card debt, retirement investing, and healthy lifestyle. Finally, we show that consumers with high EPO levels exhibit more effective self-regulation when faced with a choice and that EPO can be primed, temporarily improving self-regulation for consumers with low EPO levels.
Electrochemical Characterization of SEI-Type Passivating Films Using Redox Shuttles

Although redox shuttles have been demonstrated to provide overcharge protection for up to 200 cycles, the existence of the solidelectrolyte-interphase (SEI), a passivating film on the negative electrode, seems to be inherently incompatible with a successful shuttle reaction. In this work, the kinetics of ferrocene is measured in the presence and absence of passivating films using rotatingdisk-electrode voltammetry. The steady-state current-voltage curve is described by a simple model of Butler-Volmer kinetics and a through-film limiting current. The presence of a passivating film decreases both the limiting current and the effective rate constant. Both parameters decrease with increased passivation time; a decreasing porosity is a possible explanation for the latter observation. The characterization method developed in this work allows direct measurements of the effect of passivating films, thus
Palladium-Catalyzed C-H Arylation Using Aryltrifluoroborates in Conjunction with a MnIII Oxidant under Mild Conditions.

This paper describes the development of a mild Pd-catalyzed C–H arylation reaction using potassium aryltrifluoroborates in conjunction with Mn(OAc)3 as the oxidant. The scope of this transformation is explored with a variety of different aryltrifluoroborates and arylpyridine substrates. Preliminary mechanistic studies suggest that the reaction proceeds via a high-valent Pd mechanism with C–H activation occurring at or before the rate determining step.
Insights into the Mechanism of Selective Olefin Epoxidation Catalyzed by [γ-(SiO4)W10O32H4]4-. A Computational Study

A mechanism for the H2O2-based epoxidation of olefins catalyzed by the lacunary polyoxometalate (POM) [γ-(SiO4)W10O32H4]4- (1) has been investigated at the DFT level. In this study, for the first time a “hydroperoxy” mechanism for this important process has been proposed. It is divided into two steps and investigated using the whole lacunary compound as a model. In the first step, a hydroperoxy (W−OOH) species and a water molecule are generated. The formation of this nonradical oxidant (W−OOH), consistent with the experimental suggestions, occurs with a barrier of 4.4 (7.2) kcal/mol (the number without parenthesis includes solvent effects in benzene, while the one with parenthesis is in the gas phase). In the second step, the O−O bond of the W−OOH species is cleaved, and an epoxide is formed. This step has a barrier of 38.7 (40.0) kcal/mol. It was found that the presence of one and two (CH3)4N+ countercations significantly reduces the rate-limiting barrier by 7.6 (8.3) and 11.9 (12.6) kcal/mol, respective...
Magnetoresistance in Double Spin Filter Tunnel Junctions with Nonmagnetic Electrodes and its Unconventional Bias Dependence

Spin filtering happens due to the discriminative tunneling probabilities for spin-up and spin-down electrons through a magnetic barrier and can result in highly spin polarized tunnel currents. Combining two such barriers in a tunnel junction thus leads to large magnetoresistance without the necessity of magnetic electrodes. We demonstrate the realization of such unconventional tunnel junctions using double EuS spin filter barriers with Al electrodes. The novel nonmonotonic and asymmetric bias behavior in magnetoresistance can be qualitatively modeled in the framework of WKB approximations.