cssi/SciSciGPT-SciSciNet huggingface dataset:
An integrated computer system for engineering problem solving

Computers should provide the mechanism that enables engineers to do better engineering. By permitting faster and more accurate and complete problem analysis to be performed, computers assist the engineer in his computational and decision making roles. The engineer today is faced with problems of increasing magnitude and complexity where the effects and interrelationships of all relevant information must be considered. The computer provides the coordinating and integrating mechanism for the problem information needed by the engineer in the decision making process. Computers enable engineers to perform total problem solutions where all pertinent information is properly considered.
Frequency-dependent chemolocation and chemotactic target selection

Chemotaxis is typically modeled in the context of cellular motion toward a static, exogenous source of chemoattractant. Here we propose a time-dependent mechanism of chemotaxis in which a self-propelled particle (e.g. a cell) releases a chemical that diffuses to fixed particles (targets) and signals the production of a second chemical by these targets. The particle then moves up concentration gradients of this second chemical, analogous to diffusive echolocation. When one target is present, we describe probe release strategies that optimize travel of the cell to the target. In the presence of multiple targets, the one selected by the cell depends on the strength and, interestingly, on the frequency of probe chemical release. Although involving an additional chemical signaling step, our chemical 'pinging' hypothesis allows for greater flexibility in regulating target selection, as seen in a number of physical or biological realizations.
Using resonance Raman spectroscopy to examine vibrational barriers to electron transfer and electronic delocalization.

A time-dependent approach to the interpretation of resonance Raman scattering intensities has been used to obtain quantitative vibrational mode displacement information from scattering intensities associated with charge-transfer excitation. The displacements and associated frequencies are the key parameters needed to understand Franck−Condon effects in electron-transfer kinetics, and to delineate in a mode-specific way the composition of vibrational reorganization energies. Application of the approach to a number of types of electron-transfer reactions is described, including symmetrical and unsymmetrical intervalence electron transfers in inorganic and organic redox systems, metal-to-ligand charge-transfer reactions, and interfacial electron-transfer reactions. Also described is how the approach can be used to elucidate mechanisms for valence delocalization in strongly interacting redox systems.
Mechanical Behavior of Fiber-Reinforced Cement-Based Composites

The use of fibers in a cement-based matrix can fundamentally improve its mechanical properties. Such improvement may lead to a new class of cement-based materials. Further developments depend on an understanding of the interaction between different fibers and cement-based matrices. The current knowledge on the mechanical behavior of fiber-reinforced cement-based composites is summarized. Toughening mechanisms, interface properties, and tensile response of fiber-reinforced cement-based composites are presented. Various theoretical approaches used to describe the mechanical behavior of fiber-reinforced composites are reviewed.
Information asymmetries and simultaneous versus sequential voting

Sequential voting takes place when some voters make choices with knowledge of earlier decisions in the same election. Historically, voting in U.S. presidential primaries is sequential, but recent primaries have been “front-loaded” into the early weeks of the season. We explore sequential voting in drawn-out primaries and simultaneous voting in front-loaded ones theoretically and use laboratory elections to examine our predictions empirically. We find evidence that in sequential voting later voters can use early outcomes to infer information about candidates and make choices that better reflect their preferences. The ability of later voters to infer information increases with higher levels of risk aversion and information provided on early outcomes. We discover that when a moderate candidate is largely unknown, information aggregation in sequential voting can increase the probability s/he will win, which supports the contention of policymakers that sequential voting can lead to different electoral outcomes.
Window effects in zeolite diffusion and brownian motion over potential barriers

Gorring (1973) reported a phenomenon, the “window effect,” whereby the diffusivities of normal paraffins within zeolite T do not decrease monotonically with increasing carbon number N, as would be expected intuitively. Rather, following an initial decrease with N, the diffusivities exhibit a local minimum at C8 followed by a pronounced local maximum at C12. This article presents a theoretical analysis of the window effect and related phenomena, based on an analogy of the configurational diffusion process with an “equivalent” one-dimensional Brownian motion of a rod through a periodic sequence of potential barriers. Numerical calculations are found to be in reasonable agreement with Gorring's experimental data and quantify his qualitatively-stated mechanism, namely that n-alkanes longer than C8 are too large to fit entirely within the potential wells formed by erionite cages and therefore experience smaller energetic barriers to diffusion.
The physics of earthquakes

Earthquakes occur as a result of global plate motion. However, this simple picture is far from complete. Some plate boundaries glide past each other smoothly, while others are punctuated by catastrophic failures. Some earthquakes stop after only a few hundred metres while others continue rupturing for a thousand kilometres. Earthquakes are sometimes triggered by other large earthquakes thousands of kilometres away. We address these questions by dissecting the observable phenomena and separating out the quantifiable features for comparison across events. We begin with a discussion of stress in the crust followed by an overview of earthquake phenomenology, focusing on the parameters that are readily measured by current seismic techniques. We briefly discuss how these parameters are related to the amplitude and frequencies of the elastic waves measured by seismometers as well as direct geodetic measurements of the Earth's deformation. We then review the major processes thought to be active during the rupture and discuss their relation to the observable parameters. We then take a longer range view by discussing how earthquakes interact as a complex system. Finally, we combine subjects to approach the key issue of earthquake initiation. This concluding discussion will require using the processes introduced in the study of rupture as well as some novel mechanisms. As our observational database improves, our computational ability accelerates and our laboratories become more refined, the next few decades promise to bring more insights on earthquakes and perhaps some answers.
Linear Stability Analysis of Resonant Periodic Motions in the Restricted Three-Body Problem

The equations of the restricted three-body problem describe the motion of a massless particle under the influence of two primaries of masses 1 − µ and µ, 0 µ 1/2, that circle each other with period equal to 2π . When µ = 0, the problem admits orbits for the massless particle that are ellipses of eccentricity e with the primary of mass 1 located at one of the focii. If the period is a rational multiple of 2π , denoted 2πp/q, some of these orbits perturb to periodic motions for µ> 0. For typical values of e and p/q, two resonant periodic motions are obtained for µ> 0. We show that the characteristic multipliers of both these motions are given by expressions of the form 1 ± √ C(e, p, q)µ+ O(µ) in the limit µ → 0. The coefficient C(e, p, q) is analytic in e at e = 0 and C(e, p, q)= O(e |p−q| ). The coefficients in front of e |p−q| , obtained when C(e, p, q) is expanded in powers of e for the two resonant periodic motions, sum to zero. Typically, if one of the two resonant periodic motions is of elliptic type the other is of hyperbolic type. We give similar results for retrograde periodic motions and discuss periodic motions that nearly collide with the primary of mass 1 − µ.
Parental urinary biomarkers of preconception exposure to bisphenol A and phthalates in relation to birth outcomes

Bisphenol A (BPA) and phthalates are ubiquitous non-persistent endocrine disrupting chemicals whose relation with infant birth size is not clearly understood. We examined associations between maternal and paternal preconception urinary concentrations of total BPA and 14 phthalate metabolites and birth size for 233 infants. Multiple linear regression models were used to estimate parental quartiles of BPA and phthalates in relation to birth weight, length, head circumference, and ponderal index with separate models run for each parent adjusting for age, smoking, body mass index, education, alcohol, parity, and creatinine. Models also included an interaction term for each chemical and infant sex and were further adjusted to include the other partner’s chemical concentrations. In maternal models adjusted for partner’s exposure and covariates, reductions in birth weight (range: 178-215 g; p < 0.05) were observed for the 2nd quartile of maternal monomethyl phthalate, mono-[(2-carboxymethyl) hexyl] phthalate and mono-n-octyl phthalate when compared with the 1st quartiles. The 3rd quartile of monoethylhexyl phthalate (mEHP) was also associated with a 200.16 g (95 % CI: -386.90, -13.42) reduction. Similar reductions in birth weight were observed for the 2nd quartile of paternal mEHP (β = -191.93 g; 95 % CI: -381.61, -2.25). Additionally, select maternal urinary metabolites were associated with decreased head circumference, birth length and gestational age. However, paternal concentrations were generally associated with increased birth length and gestational age. We observed some suggestion that preconception maternal and paternal urinary concentration of BPA and specific phthalate metabolites may be associated with smaller birth size and increased gestational age, though the findings appeared to be parent and chemical specific.
Private and Public Preferences

The theory of revealed preference, which lies at the core of the neoclassical economic method, asserts that people's preference orderings are revealed by their actions. This assertion has two possible meanings, of which one is a truism and the other false. When a person joins a riot against the government, he reveals through this action that he would rather riot than not. This is the sense in which the assertion is a truism. But if one means that the person must want a change of government, this is certainly false. His decision to riot could mean only that he considers it dangerous to stay on the sidelines.
Determination of changes in streamflow variance by means of a wavelet-based test

[1] Changes in the variance of streamflow over time may possibly be caused by land cover changes or climate changes. Knowledge of these possible changes in the time series structure is desirable for validation of modeling efforts; detection is not always straightforward, however. We present the use of a wavelet-based statistical test for the detection of changes in the variance of a time series applied to records of streamflow from 12 rivers in the United States from the period 1954–1999. The test is able to show during which time periods and at what wavelet scales changes in the variance are taking place. It is found that the major similarities in variance change for all the streamflow time series exist when the largest time domain wavelet is used and also when a wavelet of the second largest frequency scale is used. Sampling considerations prevent exact localization of the time and frequency of the change(s). Results of the test indicate that for the data analyzed in this study a change in the variance of the streamflow time series most likely did take place over the time period examined.
Synthesis of 2-epi-Amphidinolide E: An Unexpected and Highly Selective C(2) Inversion During an Esterification Reaction

A synthesis of 2-epi-amphidinolide E (1) has been accomplished via an unexpected and highly diastereoselective C(2) stereochemical inversion during the modified Yamaguchi esterification of alcohol 4b and Fe(CO)3-complexed dienoic acid 7.
Expected Utility Asset Allocation

Most asset allocation analyses use the mean–variance approach for analyzing the trade-off between risk and expected return. Analysts use quadratic programming to find optimal asset mixes and the characteristics of the capital asset pricing model to determine reasonable optimization inputs. This article presents an alternative approach in which the goal of asset allocation is to maximize expected utility, where the utility function may be more complex than that associated with mean–variance analysis. Inputs for the analysis are based on the assumption of asset prices that would prevail if there were a single representative investor who desired to maximize expected utility.
A North American Free Trade Agreement: Analytical Issues and a Computational Assessment

The following sections are included:IntroductionIssues in Analyzing the Economic Impact of the NAFTAThe Computational ModelComputational ResultsConclusionsStudy QuestionsReferencesSuggested Further Reading
Mold2, Molecular Descriptors from 2D Structures for Chemoinformatics and Toxicoinformatics

Research applications in chemoinformatics and toxicoinformatics increasingly use representations of molecules in the form of numerical descriptors that capture the structural characteristics and properties of molecules. These representations are useful for ADME/toxicity prediction, diversity analysis, library design, QSAR/ QSPR, virtual screening, and other purposes. Molecular descriptors have ranged from relatively simple forms calculated from simple two-dimensional (2D) chemical structures to more complex forms representing three-dimensional (3D) chemical structures or complex molecular fingerprints consisting of numerous bit positions to represent specific chemical information. The Mold 2 software was developed to enable the rapid calculation of a large and diverse set of descriptors encoding two-dimensional chemical structure information. Comparative analysis of Mold 2 descriptors with those calculated by Cerius 2 , Dragon, and Molconn-Z on several data sets using Shannon entropy analysis demonstrated that Mold 2 descriptors convey a similar amount of information. In addition, using the same classification method, slightly better models were generated using Mold 2 descriptors compared to those generated using descriptors from the compared commercial software packages. The low computing cost for Mold 2 makes it suitable not only for small data sets, such as in QSAR, but also for large databases in virtual screening. High reproducibility and reliability are expected because Mold 2 does not require 3D structures. Mold 2 is freely available to the public (http://www.fda.gov/
On Measuring the Effects of Fiscal Policy in Recessions

We do not have a good measure of the effects of fiscal policy in a recession because the methods that we use to estimate the effects of fiscal policy—both those using the observed outcomes following different policies in aggregate data and those studying counterfactuals in fitted model economies—almost entirely ignore the state of the economy and estimate "the" government multiplier, which is presumably a weighted average of the one we care about—the multiplier in a recession—and one we care less about—the multiplier in an expansion. Notable exceptions to this general claim sug gest this difference is potentially large. Our lack of knowledge stems significantly from the focus on linear dynamics: vector autoregressions and linearized (or close-to-linear) dynamic stochastic general equilibrium (DSGE) models. Our lack of knowledge also reflects a lack of data: deep recessions are few and nonlinearities hard to measure. The lack of statistical power in the estimation of nonlinear models using aggregate data can be addressed by exploiting estimates of partial-equilibrium responses in disaggregated data. Microeconomic estimates of the partial-equilibrium causal effects of a policy can discipline the causal channels inherent in any DSGE model of the general equilibrium effects of policy. Microeconomic studies can also provide measures of the dependence of the effects of a policy on the states of different agents, which is a key component of the dependence of the general-equilibrium effects of fiscal policy on the state of the
Critical points for random Boolean networks

A model of cellular metabolism due to S. Kauffman is analyzed. It consists of a network of Boolean gates randomly assembled according to a probability distribution. It is shown that the behavior of the network depends very critically on certain simple algebraic parameters of the distribution. In some cases, the analytic results support conclusions based on simulations of random Boolean networks, but in other cases, they do not.
ScaffMatch: scaffolding algorithm based on maximum weight matching.

MOTIVATION Next-generation high-throughput sequencing has become a state-of-the-art technique in genome assembly. Scaffolding is one of the main stages of the assembly pipeline. During this stage, contigs assembled from the paired-end reads are merged into bigger chains called scaffolds. Because of a high level of statistical noise, chimeric reads, and genome repeats the problem of scaffolding is a challenging task. Current scaffolding software packages widely vary in their quality and are highly dependent on the read data quality and genome complexity. There are no clear winners and multiple opportunities for further improvements of the tools still exist. RESULTS This article presents an efficient scaffolding algorithm ScaffMatch that is able to handle reads with both short ( 35 000 bp) insert sizes producing high-quality scaffolds. We evaluate our scaffolding tool with the F score and other metrics (N50, corrected N50) on eight datasets comparing it with the most available packages. Our experiments show that ScaffMatch is the tool of preference for the most datasets. AVAILABILITY AND IMPLEMENTATION The source code is available at http://alan.cs.gsu.edu/NGS/?q=content/scaffmatch. CONTACT mandric@cs.gsu.edu SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
When Does It Pay to Delay Supplier Qualification? Theory and Experiments

We study a procurement setting in which the buyer seeks a low price but will not allocate the contract to a supplier who has not passed qualification screening. Qualification screening is costly for the buyer, involving product tests, site visits, and interviews. In addition to a qualified incumbent supplier, the buyer has an entrant of unknown qualification. The buyer wishes to run a price-only, open-descending reverse auction between the incumbent and the entrant, and faces a strategic choice about whether to perform qualification screening on the entrant before or after the auction. We analytically study the buyer's optimal strategy, accounting for the fact that under postauction qualification, the incumbent knows he could lose the auction but still win the contract. In our analysis, we derive the incumbent's optimal bidding strategy under postauction qualification and find that he follows a threshold structure in which high-cost incumbents hold back on bidding---or even boycott the auction---to preserve their profit margin, and only lower-cost incumbents bid to win. These results are strikingly different from the usual open-descending auction analysis where all bidders are fully qualified and bidding to win is always a dominant strategy. We test our analytical results in the laboratory, with human subjects. We find that qualitatively our theoretical predictions hold up quite well, although incumbent suppliers bid somewhat more aggressively than the theory predicts, making buyers more inclined to use postauction qualification. This paper was accepted by Martin Lariviere, operations management.
An active particle accelerator

It is pointed out that, although a static charge is difficult to maintain on macroscopic particles, it is straightforward to construct a small object with regularly oscillating electric dipole moment. For objects of a given size, one may then construct an accelerator by appropriately matching the frequency and separations of an external array of electrodes to this size. Physically feasible size ranges, an accelerator design, and possible applications of such systems are discussed. >
Learning contact-rich manipulation skills with guided policy search

Autonomous learning of object manipulation skills can enable robots to acquire rich behavioral repertoires that scale to the variety of objects found in the real world. However, current motion skill learning methods typically restrict the behavior to a compact, low-dimensional representation, limiting its expressiveness and generality. In this paper, we extend a recently developed policy search method [1] and use it to learn a range of dynamic manipulation behaviors with highly general policy representations, without using known models or example demonstrations. Our approach learns a set of trajectories for the desired motion skill by using iteratively refitted time-varying linear models, and then unifies these trajectories into a single control policy that can generalize to new situations. To enable this method to run on a real robot, we introduce several improvements that reduce the sample count and automate parameter selection. We show that our method can acquire fast, fluent behaviors after only minutes of interaction time, and can learn robust controllers for complex tasks, including putting together a toy airplane, stacking tight-fitting lego blocks, placing wooden rings onto tight-fitting pegs, inserting a shoe tree into a shoe, and screwing bottle caps onto bottles.
On Normal Forms of Nonlinear Systems Affine in Control

The nonlinear equivalences of both finite and infinite zero structures of linear systems have been well understood for single input single output systems and have found many applications in nonlinear control theory. The extensions of these notions to multiple input multiple output systems have proven to be highly sophisticated. In this paper, we propose constructive algorithms for decomposing a nonlinear system that is affine in control. These algorithms require modest assumptions on the system and apply to general multiple input multiple output systems that do not necessarily have the same number of inputs and outputs. They lead to various normal form representations and reveal the structure at infinity, the zero dynamics and the invertibility properties, all of which represent nonlinear equivalences of relevant linear system structural properties.
Compressive origin-destination estimation

The paper presents an approach to estimate Origin-Destination (OD) flows and their path splits, based on traffic counts on links in the network. The approach called Compressive Origin-Destination Estimation (CODE) is inspired by Compressive Sensing (CS) techniques. Even though the estimation problem is underdetermined, CODE recovers the unknown variables exactly when the number of alternative paths for each OD pair is small. Noiseless, noisy, and weighted versions of CODE are illustrated for synthetic networks, and with real data for a small region in East Providence. CODE's versatility is suggested by its use to estimate the number of vehicles and the Vehicle-Miles Traveled (VMT) using link counts.
The ideal envelope of an operator algebra

A left ideal of any C � -algebra is an example of an operator algebra with a right contractive approximate identity (r.c.a.i.). Conversely, we show here and in (6) that operator algebras with r.c.a.i. should be studied in terms of a certain left ideal of a C � -algebra. We study operator algebras and their multiplier algebras from the perspective of 'Hamana theory' and using the multiplier algebras introduced by the first author.
Could the GRB-Supernovae GRB 031203 and XRF 060218 be Cosmic Twins?

The gamma-ray burst (GRB) / X-ray flash (XRF) events GRB031203, discovered by INTEGRAL, and XRF060218, discovered by Swift, represent two of only five GRB-SNe with optical spectroscopic confirmation of their SN components. Yet their observed high-energy properties offer a sharp contrast: While GRB031203 was detected as a short 40-s burst with a spectrum peaking at Epeak > 190keV, XRF060218 was a T90 � 2100-s long, smoothly evolving burst with peak energy Epeak = 4:9keV. At the same time, the properties of the two expanding dust-scattered X-ray halos observed in a fast-response XMM-Newton observation of GRB031203 reveal that this event was accompanied by an “X-ray blast” with fluence comparable to or greater than that of the prompt gamma-ray event. Taking this observation as our starting point, we investigate the likely properties of the X-ray blast from GRB031203 via detailed modeling of the XMM data, discovering a third halo due to scattering off a more distant dust sheet at d3 = 9:94 ± 0:39kpc, and constraining the timing of the X-ray blast relative to the GRB trigger time to be t0 = 11 ± 417s. Using our constraints, we compare the properties of GRB031203 to those of other GRB-SNe in order to understand the likely nature of its X-ray blast, concluding that a bright X-ray flare, as in GRB050502B, or shock breakout event, as in XRF060218, provide the most likely explanations. In the latter case, we consider the added possibility that XRF060218 may have manifested an episode of bright gamma-ray emission prior to the burst observed by Swift, in which case GRB031203 and XRF060218 would be “cosmic twin” explosions with nearly identical high-energy properties.
The educational process and programmed instruction

THE CHANGES WHICH have and are taking place in the United States can be ascertained by the most casual observer. The tempo of change has accelerated within our own lifetimes, and as the mere business of living from day to day becomes more complex, countless new demands are made upon our schools. We have experienced an expo nential growth in the production of radios since the crystal sets of 1923 and of passenger cars since 1905. We are now experiencing perhaps an even more rapid growth with regard to television. Un doubtedly the number of jet-passenger miles has increased greatly during the past three or four years. What we learn from this is that the development of an industry from a zero point to a point of near saturation covers a period of time smaller than that during which any youth is required to attend school. Thus, each individual emerges from school into a world whose technological development and political and social organization differs consider ably from that of the world into which he was born. The implications of this last statement for educa tion are horrendous, for accompanying the growth in population is the equally frightening explosion of knowledge. Thus, to the two great problems in modern education, quantity and quality, there seem to be no easy answers. Since the dawn of the space age on October 4, 1957, many critics of Americ?n education, no longer earthbound, contend that we must choose be tween educating a small segment of our population exceedingly well and trying to educate the remaining mass less well. This is an assumption that has not as yet been proved; and yet, American education is urgently in need of re examination and improve ment and we have been reluctant to make the hard decisions necessary to galvanize us into action. This has stemmed primarily from a lack of psycho logical ownership or a shortage of beliefs to which all schooling can be tied. Until the people have psy chological ownership of the schools, they cannot know what they want education to do. And now, to make the picture even more complex, conferences are being held to consider the potential for learning of a new arrival on the educational scene, a newcomer which may in the immediate years ahead trigger the mass production of teaching materials for individualized instruction comparable in sheer magnitude to the growth we have experienced rela tive to the production of radio and television sets. This newcomer is improperly termed a teaching machine which does not teach. 11 simply brings a potential learner in contact with material it presents or that which was programmed by a person or team of persons. Skinner has this to say:
Azirine ligation: fast and selective protein conjugation via photoinduced azirine-alkene cycloaddition.

We report a new bioorthogonal ligation reaction between p-nitrodiphenylazirine and dimethyl fumarate. This photoinduced azirine–alkene cycloaddition provides a rapid (∼2 min) and highly selective route to protein conjugation at neutral pH and room temperature in biological medium.
Sharing, knowledge management and big data: A partial genealogy of the data scientist:

This article is a partial genealogy of the data scientist, meant as a contribution to understanding how both big data and the subject who mines it have come to be. It adds to the growing criticism of data mining by considering how big data might be used to manage the very workers who ostensibly command it. The article traces the concept of ‘sharing’ as it appears in discourses about the knowledge economy, arguing that knowledge sharing produces messy excesses of data. It then traces what is not shared: the knowledge workers capable of mining that data to produce value. It concludes by tracing how the act of sharing knowledge is used to undermine the power of the very subject called forth to command the excesses of sharing. It concludes by describing a reversal: data will become scarce while the ability to mine it ubiquitous and cheap.
The V-filtration for tame unit F-crystals

Let \(X\) be a smooth variety over an algebraically closed field of characteristic \(p > 0, Z\) a smooth divisor, and \(j: U=X {\setminus } Z \rightarrow X\) the natural inclusion. We introduce in an axiomatic way the notion of a \(V\)-filtration on unit \(F\)-crystals and prove such axioms determine a unique filtration. It is shown that if \(\mathcal M \) is a tame unit \(F\)-crystal on \(U\), then such a \(V\)-filtration along \(Z\) exists on \(j_*\mathcal M \). The degree zero component of the associated graded module is proven to be the (unipotent) nearby cycles functor of Grothendieck and Deligne under the Emerton–Kisin Riemann–Hilbert correspondence. A few applications to \(\mathbb A ^1\) and gluing are then discussed.
Facile alkane functionalization in copper-[2.1.1]-(2,6)-pyridinophane-PhINTs systems

Mild catalytic dehydrogenation of cycloalkanes (cyclo-C5H10, cyclo-C6H12, cyclo-C8H16) and aziridination of resulting olefins is reported with PhINTs and copper-[2.1.1]-(2,6)-pyridinophane (L) complexes LCuXn (n = 1, 2; X = Cl, OTf) “activated” with NaBArF4 in dichloromethane solution.
Design and fabrication of a multi-element corrector magnet for the Fermilab Booster synchrotron

To better control the beam position, tune, and chromaticity in the Fermilab Booster synchrotron, a new package of six corrector elements has been designed, incorporating both normal and skew orientations of dipole, quadrupole, and sextupole magnets. The devices are under construction and installation at 48 locations is planned. The density of elements and the rapid slew rate have posed special challenges. The magnet construction is presented along with DC measurements of the magnetic field.
Synthesis and biological activity of 14-hydroxydocetaxel

Abstract New taxoids, 14β-hydroxydicetaxek abd uts 1m14-acetonide, are synthesized from 14β-hydroxy-10-deacetylbaccatin III in good yields. The cytotoxicity of the new taxoids are evaluated against different human tumor cell lines and their ability to inhibit the microtubules disassembly examined. 14β-hydroxydocetaxel shows very strong cytotoxicity, especially against A549 human non-small cell lung cancer cell line (IC 50 = 0.8 nM).
From chaos to disorder: Statistics of the eigenfunctions of microwave cavities

We study the statistics of the experimental eigenfunctions of chaotic and disordered microwave billiards in terms of the moments of their spatial distributions, such as the inverse participation ratio (IPR) and density-density auto-correlation. A path from chaos to disorder is described in terms of increasing IPR. In the chaotic, ballistic limit, the data correspond well with universal results from random matrix theory. Deviations from universal distributions are observed due to disorder induced localization, and for the weakly disordered case the data are well-described by including finite conductance and mean free path contributions in the framework of nonlinear sigma models of supersymmetry.
Shock-Wave Interaction with Two-Dimensional Bodies

The physical problem considered in this paper is that of a plane shock wave interacting with a two-dimensional body on or near a ground plane in an initially stagnant flow. The fluid is assumed to be an inviscid, perfect gas with a constant specific heat ratio of 1.4. The method developed by Godunov, Zabrodyn, and Prokopov * used to numerically solve the unsteady gas dynamic equations is stable because it implicitly contains an artificial viscosity. The numerical scheme is firstorder accurate in both space and time. However, comparative studies done by Taylor, Ndefo, and Masson2 indicate that the Godunov method gives good results when compared with higher-order numerical techniques. Each of the calculations described herein required 30 to 60 minutes on an IBM 370. (Recent experience running the code on a CDC 7600 indicates that this corresponds to 5 to 10 min of 7600 running time.)
Discovery of directional and nondirectional pioneer transcription factors by modeling DNase profile magnitude and shape

Here we describe Protein Interaction Quantitation (PIQ), a computational method that models the magnitude and shape of genome-wide DNase profiles to facilitate the identification of transcription factor (TF) binding sites. Through the use of machine learning techniques, PIQ identified binding sites for >700 TFs from one DNase-seq experiment with accuracy comparable to ChIP-seq for motif-associated TFs (median AUC=0.93 across 303 TFs). We applied PIQ to analyze DNase-seq data from mouse embryonic stem cells differentiating into pre-pancreatic and intestinal endoderm. We identified (n=120) and experimentally validated eight ‘pioneer’ TF families that dynamically open chromatin, enabling other TFs to bind to adjacent DNA. Four pioneer TF families only open chromatin in one direction from their motifs. Furthermore, we identified a class of ‘settler’ TFs whose genomic binding is principally governed by proximity to open chromatin. Our results support a model of hierarchical TF binding in which directional and non-directional pioneer activity shapes the chromatin landscape for population by settler TFs.
A Turbulent Model of Gamma-Ray Burst Variability

A popular paradigm to explain the rapid temporal variability observed in gamma-ray burst (GRB) light curves is the internal shock model. We propose an alternative model in which the radiating fluid in the GRB shell is relativistically turbulent with a typical eddy Lorentz factor γ t. In this model, all pulses in the gamma-ray light curve are produced at roughly the same
School Reform 2007: Transforming Education into a Scientific Enterprise

AbstractThe article begins with a brief review of prior school reform movements and how and why they are different from today. Unlike past reform movements, school reform efforts are now focused on two key ideas: performance and scientific evidence. Motivated in part by economic considerations, the underlying rationale for many school reform programs is to raise the performance of U.S. students by strengthening their knowledge base and skills. Similarly, the emphasis on scientific evidence can be viewed as an economic global response to rising costs of research and development in fields such as medicine, criminology, and social welfare. This focus on performance and scientific evidence is embodied in the No Child Left Behind Act of 2001 (NCLB), which expanded the federal role in education and substantially altered what the purpose of education should be, when and how it should be measured, and what type of evidence should be used for its improvement. The review concludes by examining how these performance...
A Comparative Evaluation of Automated Solar Filament Detection

We present a comparative evaluation for automated filament detection in Hα solar images. By using metadata produced by the Advanced Automated Filament Detection and Characterization Code (AAFDCC) module, we adapted our trainable feature recognition (TFR) module to accurately detect regions in solar images containing filaments. We first analyze the AAFDCC module’s metadata and then transform it into labeled datasets for machine-learning classification. Visualizations of data transformations and classification results are presented and accompanied by statistical findings. Our results confirm the reliable event reporting of the AAFDCC module and establishes our TFR module’s ability to effectively detect solar filaments in Hα solar images.
Reconciling conflicting evidence on the elasticity of intertemporal substitution: A macroeconomic perspective

This paper attempts to reconcile two opposing views about the elasticity of intertemporal substitution in consumption (EIS), a parameter that plays a key role in macroeconomic analysis. On the one hand, empirical studies using aggregate consumption data typically find that the EIS is close to zero (Hall, 1988). On the other hand, calibrated macroeconomic models designed to match growth and business cycle facts typically require that the EIS be close to one (Weil, 1989; Lucas, 1990). We show that this apparent contradiction arises from ignoring two kinds of heterogeneity across individuals. First, a large fraction of U.S. households do not participate in stock markets. Second, a variety of microeconomic studies using individual-level data conclude that an individual’s EIS increases with his wealth. We study a dynamic macroeconomic model featuring these two realistic sources of heterogeneity which have been largely assumed away in macroeconomics to date. We find that limited participation creates substantial wealth inequality matching that in U.S. data. Consequently, the properties of aggregate variables directly linked to wealth, such as investment and output, are almost entirely determined by the (high-elasticity) stockholders. At the same time, since consumption is much more evenly distributed across households than is wealth, estimation using aggregate consumption uncovers the low EIS of the majority of households (i.e., the poor).
Explaining the Pathways between Approach-Avoidance Personality Traits and Employees’ Job Search Behavior

Research suggests that certain personality characteristics lead to greater (or lesser) withdrawal from work, yet little research has examined exactly how personality translates into withdrawal behavior. To address this question, the present study demonstrated that the approach-avoidance personality traits of extraversion and neuroticism each showed simultaneous positive and negative effects on job search behaviors of employed individuals depending on the mediating mechanism involved (i.e., ambition values, job search self-efficacy, perceived job challenge, work burnout, perceived financial inadequacy, and job satisfaction). The authors’ findings extend theoretical insights on the pathways linking dispositional traits and employee withdrawal behaviors and suggest how employers can more precisely anticipate and mitigate employees’ search for new employment.
A Transfer Standard for Optical Fiber Power Metrology

We have developed and evaluated a transfer standard for the calibration of optical fiber power meters over the wavelength range from 750–1800 nm. The transfer standard is an optical-trap detector consisting of two germanium (Ge) photodiodes, and a spherical mirror. The photodiodes and mirror are contained in a package that is thermally stable and accepts a variety of optical fiber connectors. Spatial uniformity measurements indicate that the variation of detector response as a function of beam position is less than ±0.15%. Comparison of the absolute responsivity for three different input conditions indicates that the detector responsivity is nearly the same for collimated beams transmitted through air, as for diverging input from an optical fiber. Small measurement-result differences between collimated and diverging inputs still remain and are discussed briefly.
Labor Market and Socioeconomic Effects on Marital Stability

Abstract This paper reports an investigation of the effects of socioeconomic and labor market factors on the dissolution of marriages since the mid 1960s. We examine the effects of possible sources of marital disruption, including poor labor market opportunities for young adults; the economic independence and improved labor market opportunities of women; and changes in the labor market roles and expectations of women within marriage. Using the National Longitudinal Surveys of Young Men, Young Women, and Youth, we estimate the effects on marital stability of husbands′ and wives′ levels, differences and changes in educational attainment, income, and annual weeks worked. Our results suggest that average levels of couples′ educational attainment and recent work experiences positively affect marital stability. The degree to which husbands and wives differ on educational attainment and income does not affect marital stability, but the more that wives work relative to their husbands, the greater the chances of disruption. Positive changes in wives′ socioeconomic and labor force characteristics over the course of their marriages increase the odds of marital disruption.
A Digital 1.6 pJ/bit Chip Identification Circuit Using Process Variations

A 128-bit, 1.6 pJ/bit, 96% stable chip ID generation circuit utilizing process variations is designed in a 0.13 mum CMOS process. The circuit consumes 162 nW from a 1 V supply at low readout frequencies and 1.6 muW at 1 Mb/s. Cross-coupled logic gates were employed to simultaneously generate, amplify, and digitize the random circuit offset to create a stable unique digital chip ID code. A thorough statistical analysis is presented in order to explore the ID circuit reliability and stability. Two ID generators with different layout techniques were designed and fabricated to provide a performance comparison of power consumption, ID stability, and ID statistical robustness.
A Randomized Controlled Trial of Early Postoperative Feeding in Gynecologic Oncology Patients Undergoing Intra-Abdominal Surgery

Abstract Objective: To evaluate the safety and efficacy of early oral feeding after intra-abdominal surgery in gynecologic oncology patients. Methods: During a 1-year period, 200 gynecologic oncology patients undergoing intra-abdominal surgery were enrolled in a randomized controlled trial of early compared with traditional oral postoperative feeding. Patients allocated to early postoperative oral feeding began a clear liquid diet on the first postoperative day and then advanced to a regular diet as tolerated. Patients allocated to traditional postoperative oral feeding received nothing by mouth until return of bowel function (defined as the passage of flatus in the absence of vomiting or abdominal distention), then began a clear liquid diet, and advanced to a regular diet as tolerated. Results: Age, case distribution, surgery length, blood loss, and first passage of flatus were similar in the early and traditional feeding groups. Significantly more patients in the early group developed nausea. Despite this, the incidence of vomiting, abdominal distention, incidence and duration of nasogastric tube use, and percentage of patients who tolerated clear liquid and regular diets on the first attempt were comparable in both groups. Time to development of bowel sounds, time to initiation of clear liquid and regular diets, and hospital stay were significantly longer in the traditional group. Major complications (eg, pneumonia, atelectasis, and wound complications) and febrile morbidity occurred equally in both groups. There were no known anastamotic complications or aspirations in either group. Postoperative changes in hematologic indices and electrolytes were comparable in both groups. Conclusion: Early postoperative feeding in gynecologic oncology patients undergoing intra-abdominal surgery is safe and well tolerated.
Exploring the kinetics of switchable polymer surfaces with dynamic tensiometry

Switchable polymer multilayer coatings consisting of poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA) were prepared via Layer-by-Layer (LbL) assembly and post-functionalized with poly(ethylene glycol methyl ether) (PEG). This resulted in a soft polar coating that reversibly and repeatedly rearranges from hydrophobic to hydrophilic (or vice versa) when contacted with water (or air). Goniometry is used to quantify the forward surface rearrangement in the form of transient measurements of the water contact angle. By examining the time evolution of the water contact angle at various temperatures, the apparent activation energy for the forward surface rearrangement (Ea,f) can be determined. Further insight can be gained into the kinetics of this surface reconstruction process by utilizing dynamic tensiometry to measure the evolution in the contact angle of a liquid meniscus at several rates and temperatures as it advances or recedes over the multilayer films. A simple first-order thermally-activated rate process is shown to describe the forward and reverse surface reconstruction and enables the shape of the measured tensiometric force curves during repeated immersion and emersion to be predicted quantitatively. Using this model we show that the character of this switchable surface coating can appear to be hydrophobic or hydrophilic depending on a single dimensionless parameter which incorporates the characteristic time-scale for temperature-dependent surface rearrangement, the speed of immersion and the capillary length of the liquid meniscus.
Discrimination and the effects of drug testing on black employment

Abstract A common assumption is that the rise of drug testing among U.S. employers must have had negative consequences for black employment. I use variation in the timing and nature of drug testing regulation to identify the impacts of testing on black hiring. I find that adoption of protesting legislation increases black employment in the testing sector by 7% to 30% and relative wages by 1.4% to 13.0%, with the largest shifts among low-skilled black men. The results are consistent with ex ante discrimination and suggest that drug testing may benefit African Americans by enabling nonusing blacks to prove their status to employers.