cssi/SciSciGPT-SciSciNet huggingface dataset:
SymFET: A proposed symmetric graphene tunneling field effect transistor

The expressions given in previous section, is for T = 0K. The room temperature results need to consider the Fermi distribution with integral over energy [7]. The corresponding device parameters are labeled in the figures. A graphene length L = 100 nm is assumed. When the tunnel barrier is thicker, the resonant peak current decreases as expected (Figure 2 (a)). Thinner t gate offers better gate control and higher gate induced doping (and more resonant current). The corresponding resonance peaks increase and shift to higher bias (Figure 2 (b)). Figure 3 explores the entire bias phase space of the I–V characteristics. Though the on/off ratio of the SymFET is not a true performance metric, from equation (1) and (3) we find it is given by I on /I off ≈ LΔE/ħv F , (∼100 for L ∼ 100nm, ∼1000 for L ∼ 1 µm). It is independent of temperature and increases with size. The I D -V DS characteristics at fixed VG are shown in Figure 4(a). In Figure 4(b), the ID-VG curve shows strong non-linear behavior. The transconductance can be large in the bias range where the resonant current peak exists. The I D -V DS curve (e.g. resonant width) is insensitive to the temperature (Figure 5), because of tunneling mechanism, except for Fermi function smearing. The slight difference at low V DS , is due to the Fermi function varying with temperature. The increase of resonant peak current is because Fermi tail extends to high energy with larger density of states. The nonlinear symmetric I D -V DS behavior can also be used for purposes of frequency multiplication; if a dc voltage bias at the current peak V DSp is superposed with an ac signal, the frequency of the output current will be doubled (Figure 6 schematic). The SymFET is expected to be intrinsically fast since it relies entirely on tunneling; high frequency digital operation and a host of analog applications such as frequency multiplication are thus possible by exploiting the symmetry of the bandstructure of 2D graphene.
Approaches in the determination of plant nutrient uptake and distribution in space flight conditions

The effective growth and development of vascular plants rely on the adequate availability of water and nutrients. Inefficiency in either the initial absorption, transportation, or distribution of these elements are factors which impinge on plant structure and metabolic integrity. The potential effect of space flight and microgravity conditions on the efficiency of these processes is unclear. Limitations in the available quantity of space-grown plant material and the sensitivity of routine analytical techniques have made an evaluation of these processes impractical. However, the recent introduction of new plant cultivating methodologies supporting the application of radionuclide elements and subsequent autoradiography techniques provides a highly sensitive investigative approach amenable to space flight studies. Experiments involving the use of gel based 'nutrient packs' and the radionuclides calcium-45 and iron-59 were conducted on the Shuttle mission STS-94. Uptake rates of the radionuclides between ground and flight plant material appeared comparable.
Quantitative Risk Assessment as a Design Tool - Recent FPSO Experience

Quantitative risk assessment was used as a tool for the conceptual and detailed design of two floating production, storage, and off-loading (FPSO) installations. Results from the risk-assessment study were used to identify significant risk contributors that influence the design and operation of the facilities and to demonstrate that the risk-acceptance criteria adopted by the company were met. The results were also used to identify opportunities to further reduce the risk to a level that is as low as reasonably practical (ALARP). Traditional risk, reliability, and consequence analysis methods were used to evaluate impacts from process and marine facilities and to determine the design of accidental loads during the conceptual engineering and design phases. Results were used as data for a detailed fault-tree analysis of accident scenarios and used to set the design criteria for significant structures and facilities. In addition, analyses of subsea facility interfaces and field operations were performed to incorporate the full development scope. Particular attention was given to subsea pipelines and flexible risers as well as tanker operations and their effects on FPSO operation and design. Event frequencies were determined from industry data and conditioned for the special design and operating features of the chosen FPSO concept. Risk sources, impacting fatal accidents, impairment of safety functions, and loss of asset value, were quantified for use in demonstrating an acceptable level of risk and to test opportunities to further reduce operating risks. Results from the analyses show that process fires and explosions dominate the risks to personnel and safety functions, followed by cargo tank explosions. Tanker collisions, subsea pipeline and riser leaks, and turret operations were found to represent significant asset risks. Design development and operations planning efforts focused on these areas to reduce risk and improve reliability.
Forecast comparisons in unstable environments

We propose new methods for comparing the out-of-sample forecasting performance of two competing models in the presence of possible instabilities. The main idea is to develop a measure of the relative local forecasting performance for the two models, and to investigate its stability over time by means of statistical tests. We propose two tests (the Fluctuation test and the One-Time Reversal test) that analyze the evolution of the models' relative performance over historical samples. In contrast to previous approaches to forecast comparison, which are based on measures of global performance, we focus on the entire time path of the models' relative performance, which may contain useful information that is lost when looking for the model that forecasts best on average. We apply our tests to the analysis of the time variation in the out-of-sample forecasting performance of monetary models of exchange rate determination relative to the random walk. Copyright © 2010 John Wiley & Sons, Ltd.
Community development in the west of Ireland: twenty years on in the Killala area

AbstractThis research returns to a 1986 Community Development Journal article, which highlighted the unique and successful locally driven community development efforts in Killala, western Ireland. Since then, a variety of social, economic, and political changes have taken place, which have reshaped Ireland and the capacity for local community action. Twenty years on, this community was revisited with the goal of assessing the changes, as well as to determine community characteristics that have persisted. This article seeks to provide an update on local conditions, presents an in-depth exploration of local grassroots efforts, and builds on the previous case study by providing an empirical exploration of the factors shaping local community agency - a mixed-method framework consisting of extensive key informant interviews, focus groups, and household survey data.
Minimizing distortion in truss structures: A comparison of simulated annealing and tabu search

Inaccuracies in the length of members and the diameters of joints of large space structures may produce unacceptable levels of surface distortion. Based on the influence matrices generated by a small deformation linear analysis, we formulate a combinatorial optimization problem to minimize surface distortion (DRMS). A deterministic heuristic, tabu search, is presented for DRMS. A comparison of the computational performance of tabu search is made with a randomized heuristic, simulated annealing. Computational experiments are performed on data generated from a two-ring, flat, tetrahedral truss structure.
A comparison of sulfur- and oxygen-modified mo(111) surfaces for methylcyclopropane hydrogenolysis: Evidence for participation by subsurface atoms in the active site

Abstract The catalytic hydrogenolysis of methylcyclopropane has been studied over the Mo(111) crystal plane as a function of preadsorbed atomic sulfur and oxygen coverage. The selectivities for the single hydrogenolysis products, isobutane and n -butane, and for the double hydrogenolysis products, methane, propane, and ethane, were the same for sulfur- and oxygen-modified surfaces and independent of modifier coverage. Sulfur and oxygen acted as poisons for the hydrogenolysis activity. The activity decreased linearly with both sulfur and oxygen coverage, but the slope of the activity decay with sulfur was three times that with oxygen. The zero activity intercept corresponded to ca. 6 × 10 14 S atoms cm 2 (one sulfur atom per unit cell) and ca. 20 × 10 14 O atoms cm 2 (three oxygen atoms per unit cell). Examination of structural models for the Mo(111) surface suggests that molybdenum atoms in the second or even third layers must participate in the active site for hydrogenolysis.
Creating a Safe Environment for Women’s Leadership Transformation

This study used qualitative data to describe how transformational learning was achieved in a women-only training (WOT) program. The article argues that an environment conducive to transformational ...
An automated finite element procedure for fatigue crack propagation analyses

Abstract This paper presents an innovative approach for mixed-mode two-dimensional fatigue crack propagation analyses of structural components via interactive computer graphics. Linear elastic fracture mechanics and the finite element method are integrated in a comprehensive computer code that determines the crack path and fatigue life for a given problem. In addition, the program has the capability of automatic finite element remeshing at any arbitrary location, angle or direction following crack nucleation or extension in a continuously monitored analysis. To demonstrate the proficiency of the program, a study was performed that investigated the fatigue life of attachment lugs. Correlation with existing experimental data and other numerical procedures verifies the accuracy of the program.
A new synthesis of the glyoxalase-I inhibitor COTC

Abstract A stereoselective, chiral synthesis of the glyoxalase I inhibitor 2-crotonyloxymethyl-(4 R ,5 R ,6 R )-4,5,6-trihydroxycyclohex-2-enone 1 (COTC) from a simple derivative of (−)-quinic acid is described.
What do adults read

A SURVEY OF THE READING HABITS of a national sample of 5,067 adults was conducted in order to determine what is being read -by whom, for how long, and for what reason and to determine how reading fits into people's daily activities. The results indicate that reading is a ubiquitous activity of American adults. A substantial portion of the waking hours of many persons is spent in reading, frequently during daily activities such as working; shopping; attending school, church, or theater; and traveling or commuting-and during recreational or free-time activities. Most reading time is spent on newspapers, magazines, books, and job-related matter. Many types of reading on which a relatively short time is spent, however, are an integral part of other activities of the individual, such as reading street or traffic signs while traveling. Although the average person reads for almost 2 hours on a typical day, people differ greatly in the amount that they read. Persons with high socioeconomic status tend to read more of all kinds of printed matter than those with low status. The 5 per cent of all adults who are unable to read have an extremely low socioeconomic status and frequently depend on others to read to them.
Forbidden transitions in a magneto-optical trap.

We report the first observation of a nondipole transition in an ultracold atomic vapor. We excite the $3P\mathrm{\text{\ensuremath{-}}}4P$ electric quadrupole ($E2$) transition in $^{23}\mathrm{N}\mathrm{a}$ confined in a magneto-optical trap, and we demonstrate its application to high-resolution spectroscopy by making the first measurement of the hyperfine structure of the $4{P}_{1/2}$ level and extracting the magnetic dipole constant $\mathrm{A}=30.6\ifmmode\pm\else\textpm\fi{}0.1\text{ }\text{ }\mathrm{M}\mathrm{H}\mathrm{z}$. We use cw optical-optical double resonance accompanied by photoionization to probe the transition.
Magnetic resonance imaging of cells in experimental disease models.

1.1. A brief history of cellular imaging The illustrious history of cellular imaging began in 1595 when spectacle makers Hans Lippershey and Hans Janssen in Middelburg, The Netherlands, developed a prototype microscope with lenses capable of threefold magnification. Using this revolutionary apparatus, Robert Hooke coined the word “cell” in 1665 upon witnessing the structure of non-living plant tissue (cork) that, to him, resembled monks’ chambers called “cellula”. Nearly a decade later, in 1674, Anton Van Leeuwenhoek became the first to describe live algae, bacteria, spermatozoa, and even blood flow in capillaries using a device equipped with hand ground lenses that were capable of greater than 200-fold magnification. Almost two centuries would pass before the seminal observations of Hooke, Leeuwenhoek, and contemporaries in botany were expanded to include animal cells by Theodor Schwann and Matthias Schleiden and cell division by Rudolf Virchow; ultimately giving rise to the universal Cell Theory stating that cells are the basic unit of life [1].
Op-Ex - An optimal-explicit guidance algorithm for powered flight outside the atmosphere

The principal difficulties in applying optimal control theory to the two-point boundaryvalue problem which describes rocket powered flight outside the atmosphere are in integrating the state and costate equations fast and accurately, and in re-estimating initial values of the costate to achieve rapid convergence. This paper describes an algorithm called Op-Ex which applies Newton's method in a standard fashion to satisfy the second difficulty, and employs an integration technique not unlike those used in current "explicit guidance" algorithms to satisfy the first. Op-Ex has flexible provisions for propulsion performance description and allows an unlimited number of rocket stages to be specified. For any trajectory phase, any of a variety of alternative terminal requirements can be easily specified, and for each, Op-Ex will generate an optimal (fuel-minimal) trajectory. Op-Ex is computationally efficient, to be practical for real-time guidance, yet is sufficiently accurate to be used for rapid prediction of fuel requirements for flight planning purposes.
Hankel Singular Values of Flexible Structures in Discrete Time

Approximate analytical expressions for controllability and observability grammian matrices and Hankel singular values of discrete LTI flexible structures are derived. The diagonal dominance property of the discrete grammians is shown which results in the invariance of the principal directions. The approximate discrete Hankel singular values converge to the continuous formula with increased sampling rate while the controllability and observability grammians go to zero and infinity respectively. The approximate formula are accurate up to frequencies close to the Nyquist.
Rationale and methods for conserving biodiversity in plantation forests

Industrial forest managers and conservation biologists agree on at least two things: (1) plantation forests can play a role in conserving biodiversity, and (2) plantations will occupy an increasing proportion of future landscapes. I review literature from around the world on the relationship between biodiversity and plantation management, structure, and yield. The dynamics of plantation ecology and management necessarily differ by landscape, geographic area, ecosystem type, etc. This review provides a broad array of management recommendations, most of which apply to most regions, and many patterns are evident. I suggest a new plantation forest paradigm based on the hypothesis that minor improvements in design and management can better conserve biodiversity, often with little or no reduction in fiber production. There is ample evidence that these methods do benefit biodiversity, and can also entail various economic benefits. Adherence to these recommendations should vary by plantation type, and depending on the proportion of the surrounding landscape or region that is or will be planted. Stand-level variables to consider include socio-economic factors, native community type and structure, crop species composition, and pest dynamics. During establishment, managers should consider innovations in snag and reserve tree management (e.g. leave strips), where mature native trees and/or understory vegetation are left unharvested or allowed to regenerate. Polycultures should be favored over monocultures by planting multiple crop species and/or leaving some native trees unharvested. Native species should generally be favored over exotics. Site-preparation should favor methods that reflect natural disturbances and conserve coarse woody debris. Plantations that have already been established by traditional design can also conserve biodiversity via small modifications to operations. Earlier thinning schedules or longer rotations can strongly affect biodiversity, as can reserve trees left after plantation harvest to remain through a second rotation.
Large Eddy Simulations of Flow and Heat Transfer in Rotating Ribbed Duct Flows

Large eddy simulations are performed in a periodic domain of a rotating square duct with normal rib turbulators. Both the Coriolis force as well as the centrifugal buoyancy forces are included in this study. A direct approach is presented for the unsteady calculation of the nondimensional temperature field in the periodic domain. The calculations are performed at a Reynolds number (Re) of 12,500, a rotation number (Ro) of 0.12, and an inlet coolant-to-wall density ratio (Δρ/ρ) of 0.13. The predicted time and space-averaged Nusselt numbers are shown to compare satisfactorily with the published experimental data. Time sequences of the vorticity components and the temperature fields are presented to understand the flow physics and the unsteady heat transfer behavior.
The sound of touch

All people have experienced hearing sounds produced when they touch and manipulate different materials. We know what it will sound like to bang our fist against a wooden door, or to crumple a piece of newspaper. We can imagine what a coffee mug will sound like if it is dropped onto a concrete floor. But our wealth of experience handling physical materials does not typically produce much intuition for operating a new electronic instrument, given the inherently arbitrary mapping from gesture to sound.
Natural Convection in Horizontal Porous Layers With Localized Heating From Below

Convective flow of fluid through saturated porous media heated from below is of considerable interest, and has been extensively studied. Most of these studies are concerned with either infinite horizontal porous layers or rectangular (or cylindrical) porous cavities with adiabatic vertical walls. A related problem of practical importance occurs when only a portion of the bottom surface is heated and the rest of it is either adiabatic or isothermally cooled. This situation is encountered in several geothermal areas which consists of troughs of volcanic debris contained by walls of nonfragmented ignimbrite. Thus, the model region considered is a locally heated long trough of isotropic porous medium confined by impermeable and insulating surroundings. Also, the recent motivation to study this problem has come from the efforts to identify a geologic repository for nuclear waste disposal. The purpose of the present work is to consider the effects of aspect ratio and Rayleigh number on free convection heat transfer from an isothermal heat source centrally located on the bottom surface of a horizontal porous cavity.
Dynamical compactification from de Sitter space

We show that D-dimensional de Sitter space is unstable to the nucleation of non-singular geometries containing spacetime regions with different numbers of macroscopic dimensions, leading to a dynamical mechanism of compactification. These and other solutions to Einstein gravity with flux and a cosmological constant are constructed by performing a dimensional reduction under the assumption of q-dimensional spherical symmetry in the full D-dimensional geometry. In addition to the familiar black holes, black branes, and compactification solutions we identify a number of new geometries, some of which are completely non-singular. The dynamical compactification mechanism populates lower-dimensional vacua very differently from false vacuum eternal inflation, which occurs entirely within the context of four-dimensions. We outline the phenomenology of the nucleation rates, finding that the dimensionality of the vacuum plays a key role and that among vacua of the same dimensionality, the rate is highest for smaller values of the cosmological constant. We consider the cosmological constant problem and propose a novel model of slow-roll inflation that is triggered by the compactification process.
A linearized Euler analysis of unsteady transonic flows in turbomachinery

A computational method for efficiently predicting unsteady transonic flows in two- and three-dimensional cascades is presented. The unsteady flow is modeled using a linearized Euler analysis whereby the unsteady flow field is decomposed into a nonlinear mean flow plus a linear harmonically varying unsteady flow. The equations that govern the perturbation flow, the linearized Euler equations, are linear variable coefficient equations. For transonic flows containing shocks, shock capturing is used to model the shock impulse (the unsteady load due to the harmonic motion of the shock). A conservative Lax-Wendroff scheme is used to obtain a set of linearized finite volume equations that describe the harmonic small disturbance behavior of the flow. Conditions under which such a discretization will correctly predict the shock impulse are investigated. Computational results are presented that demonstrate the accuracy and efficiency of the present method as well as the essential role of unsteady shock impulse loads on the flutter stability of fans.
Chandra and RXTE Spectra of the Burster GS 1826-238

Using simultaneous observations from the Chandra X-Ray Observatory and the Rossi X-Ray Timing Explorer (RXTE), we investigated the low-mass X-ray binary (LMXB) and clocked burster GS 1826-238 with the goal of studying its spectral and timing properties. The uninterrupted Chandra observation captured six bursts (RXTE saw three of the six), yielding a recurrence time of 3.54 ± 0.03 hr. Using the proportional counter array on board RXTE, we made a probable detection of 611 Hz burst oscillations in the decaying phases of the bursts with an average rms signal amplitude of 4.8%. The integrated persistent emission spectrum can be described as the dual Comptonization of ~0.3 keV soft photons by a plasma with kTe ~ 20 keV and τ ~ 2.6 (interpreted as emission from the accretion disk corona), plus the Comptonization of hotter ~0.8 keV seed photons by a ~6.8 keV plasma (interpreted as emission from or near the boundary layer). We discovered evidence for a neutral Fe Kα emission line, and we found interstellar Fe L II and Fe L III absorption features. The burst spectrum can be fit by fixing the disk Comptonization parameters to the persistent emission best-fit values and adding a blackbody. The temperature of the boundary layer seed photons was tied to the blackbody temperature. The blackbody/seed photon temperature at the peak of the burst is ~1.8 keV and returns to ~0.8 keV over 200 s. The blackbody radius is consistent with Rbb ≈ 10.3-11.7 km, assuming a distance of 6 kpc, though this value cannot be interpreted as the physical size of the neutron star due to partial covering of the stellar surface by the accretion disk. By accounting for the fraction of the surface that is obscured by the disk as a function of binary inclination, we determined the source distance must actually be near 5 kpc in order for the stellar radius to lie within the commonly assumed range of 10-12 km. The order of magnitude increase in flux at burst peak is seen to cause Compton cooling of the electron plasma surrounding the disk, as the plasma temperature decreases to ~3 keV at burst onset, and then slowly returns to the persistent emission value after about 150 s.
Kerr metric, geodesic motion, and Flyby Anomaly in fourth-order Conformal Gravity

In this paper we analyze the Kerr geometry in the context of Conformal Gravity, an alternative theory of gravitation, which is a direct extension of General Relativity (GR). Following previous studies in the literature, we introduce an explicit expression of the Kerr metric in Conformal Gravity, which naturally reduces to the standard GR Kerr geometry in the absence of Conformal Gravity effects. As in the standard case, we show that the Hamilton–Jacobi equation governing geodesic motion in a space-time based on this geometry is indeed separable and that a fourth constant of motion—similar to Carter’s constant—can also be introduced in Conformal Gravity. Consequently, we derive the fundamental equations of geodesic motion and show that the problem of solving these equations can be reduced to one of quadratures. In particular, we study the resulting time-like geodesics in Conformal Gravity Kerr geometry by numerically integrating the equations of motion for Earth flyby trajectories of spacecraft. We then compare our results with the existing data of the Flyby Anomaly in order to ascertain whether Conformal Gravity corrections are possibly the origin of this gravitational anomaly. Although Conformal Gravity slightly affects the trajectories of geodesic motion around a rotating spherical object, we show that these corrections are minimal and are not expected to be the origin of the Flyby Anomaly, unless conformal parameters are drastically different from current estimates. Therefore, our results confirm previous analyses, showing that modifications due to Conformal Gravity are not likely to be detected at the Solar System level, but might affect gravity at the galactic or cosmological scale.
Cyclotomic constructions of skew Hadamard difference sets

We revisit the old idea of constructing difference sets from cyclotomic classes. Two constructions of skew Hadamard difference sets are given in the additive groups of finite fields by using union of cyclotomic classes of F"q of order N=2p"1^m, where p"1 is a prime and m a positive integer. Our main tools are index 2 Gauss sums, instead of cyclotomic numbers.
Position and Rotation Estimation for Mobile Robots in Outside of Recording Path Using Ego-Motion

SUMMARY In this research, estimating the position and rotation of a mobile robot outside of a recording path is realized by applying ego-motion to view-based navigation. The ego-motion is calculated based on the differences in 3D positions of SURF feature points between recording and current images obtained by a Kinect sensor. In conventional view-based navigation, it is difficult to plan another path when people and objects are found in the recording path. By using the authors’ proposed estimation method, it is possible to realize flexible path planning in actual environments that include people and objects. Based on the results of experiments performed in actual indoor environments, the authors evaluated measurement accuracy for the robot's position and rotation estimated under their method, and confirmed the viability of their method for actual environments including people and objects.
Renegotiation-Proof Dynamic Contracts with Private Information

This paper studies the issue of renegotiation in a model of dynamic moral hazard. I introduce the notion of a renegotiation-proof dynamic contract. I show that the constraint of renegotiation-proofness can have the effect of setting a higher lower bound to the set of attainable expected utilities of the agent. This result extends the notion of “credit rationing” from the static models of optimal contracting to a dynamic setting and is useful for thinking about competition for long-term contracts. This result also has implications for the long-run behavior of the expected utility of the agent under dynamic contracting. Journal of Economic Literature Classification Numbers: 026, 315.
Tutorial on combustible dust

This article provides an overview of combustible dust. A summary of recent combustible dust incidents and the variety of types of materials that can represent a combustible dust hazard when present in a particulate form are provided. Fundamentals of combustible dust are covered, comparing and contrasting combustible dust to flammable gases and vapors. Test methods used to characterize the hazards of combustible dust are reviewed. Relevant standards and regulations are described. Finally, guidance on the primary methods to prevent and mitigate combustible dust incidents is summarized. © 2013 American Institute of Chemical Engineers Process Saf Prog 32: 298–306, 2013
An Organizational Perspective of Corruption

abstract An organizational view of corruption is a frontier and challenging issue in the realm of management and organization research. This article elucidates four interrelated yet sequential issues that collectively constitute organizational explanations of corruption: (i) corruption and organizational environment; (ii) corruption and organizational behaviour; (iii) corruption and organizational consequences; and (iv) corruption and organizational architecture. Specifically, it (1) offers taxonomic metaphors that identify different corrupt organizations on the basis of corruption scale and hierarchical involvement; (2) defines task environments (oligopoly intensity, regulatory control and structural uncertainty) and institutional environments (opaqueness, injustice and complexity) that stimulate illicit acts; (3) confers a typology of corrupt behaviors that align with these task and institutional environments and correspond to different metaphors (system malfeasance, procedural malfeasance, categorical malfeasance and structural malfeasance); (4) develops the logic that corruption impedes organizational development through quadri-damages (evolutionary hazard, strategic impediment, competitive disadvantage and organizational deficiency; and (5) illuminates a corruption-resisting architecture comprising corporate culture, organizational structure and compliance system.
Assessing the “Rothstein Falsification Test”: Does It Really Show Teacher Value-Added Models Are Biased?

AbstractIn an influential paper, Jesse Rothstein (2010) shows that standard value-added models (VAMs) suggest implausible and large future teacher effects on past student achievement. This is the basis of a falsification test that appears to indicate bias in typical VAM estimates of teacher contributions to student learning on standardized tests. We find that the “Rothstein falsification test” generates large and implausible future teacher effects even when students are randomly assigned to classrooms. Importantly, we also show that although the test can determine when students are tracked to teachers, this tracking result does not necessarily imply bias in estimates of teacher effectiveness. The primary reason that the test does not imply bias is that tracking could be based on lagged student achievement, which is usually accounted for in VAMs. Specifically, we show theoretically and through simulations that the test proposed in Rothstein will often falsify VAMs that are unbiased and fail to falsify VAMs...
Semisimple weak Hopf algebras

Abstract We develop the theory of semisimple weak Hopf algebras and obtain analogues of a number of classical results for ordinary semisimple Hopf algebras. We prove a criterion for semisimplicity and analyze the square of the antipode S 2 of a semisimple weak Hopf algebra A . We explain how the Frobenius–Perron dimensions of irreducible A -modules and eigenvalues of S 2 can be computed using the inclusion matrix associated to A . A trace formula of Larson and Radford is extended to a relation between the categorical and Frobenius–Perron dimensions of A . Finally, an analogue of the Class Equation of Kac and Zhu is established and properties of A -module algebras and their dimensions are studied.
The BATSE Gamma-Ray Burst Spectral Catalog. I. High Time Resolution Spectroscopy of Bright Bursts Using High Energy Resolution Data

This is the first in a series of gamma-ray burst spectroscopy catalogs from the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory, each covering a different aspect of burst phenomenology. In this paper, we present time sequences of spectral fit parameters for 156 bursts selected for either their high peak flux or fluence. All bursts have at least eight spectra in excess of 45 σ above background and span burst durations from 1.66 to 278 s. Individual spectral accumulations are typically 128 ms long at the peak of the brightest events but can be as short as 16 ms, depending on the type of data selected. We have used mostly high energy resolution data from the Large Area Detectors, covering an energy range of typically 28-1800 keV. The spectral model chosen is from a small empirically determined set of functions, such as the well-known "GRB" function, that best fits the time-averaged burst spectra. Thus, there are generally three spectral shape parameters available for each of the 5500 total spectra: a low-energy power-law index, a characteristic break energy, and possibly a high-energy power-law index. We present the distributions of the observed sets of these parameters and comment on their implications. The complete set of data that accompanies this paper is necessarily large and thus is archived in the electronic edition of the Astrophysical Journal.
Analog Signal Processing for the Time Projection Chamber

The Time Projection Chamber (TPC) is a large gas filled cylindrical detector designed to provide 3-D images of tracks radiating from the center of the detector where e+ e- collisions occur. Ionization along the tracks is drifted in an electric field to the end planes which are equipped with a large array of proportional wires and position pads (17,000 channels). The wire signals are used to derive radial data while the pad signals provide the azmuthal information. The axial dimension is determined using the drift time of the ionization. Preamplifiers mounted in the ends of the chamber feed the signals to remote amplifiers whose outputs drive Charge Coupled Devices (CCD). The CCDs are normally clocked at 10 MHz and hold a 45.5 ?s history (445 CCD buckets) of analog drift information from the TPC. During readout the clock is changed to 20 KHz and 17,000 CCD outputs are digitized (9 bits) in parallel. The non-zero data is then transferred to buffer memories associated with the digitizers. This paper emphasizes the analog signal processing part of the system.
Average chemical properties and potential formation pathways of highly oxidized organic aerosol

Measurements of ambient organic aerosol indicate that a substantial fraction is highly oxidized and low in volatility, but this fraction is generally not reproduced well in either laboratory studies or models. Here we describe a new approach for constraining the viable precursors and formation pathways of highly oxidized organic aerosol, by starting with the oxidized product and considering the possible reverse reactions, using a set of simple chemical rules. The focus of this work is low-volatility oxidized organic aerosol (LV-OOA), determined from factor analysis of aerosol mass spectrometer data. The elemental composition and volatility of the aerosol enable the determination of its position in a three-dimensional chemical space (defined by H/C, O/C, and carbon number) and thus its average chemical formula. Consideration of possible back-reactions then defines the movement taken through this chemical space, constraining potential reaction pathways and precursors. This approach is taken for two highly oxidized aerosol types, an average of LV-OOA factors from ten field campaigns (average formula C10.5H13.4O7.3), and extremely oxidized LV-OOA (from Mexico City, average formula C10H12.1O8.4). Results suggest that potential formation pathways include functionalization reactions that add multiple functional groups per oxidation step, oligomerization of highly oxidized precursors, and, in some cases, fragmentation reactions that involve the loss of small, reduced fragments.
Integrated Sachs–Wolfe effect in the era of precision cosmology

Abstract Recent detection of the Integrated Sachs–Wolfe (ISW) effect through correlation of the cosmic microwave background temperature anisotropy with traces of large scale structure provided independent evidence for the expansion of the universe being dominated by something other than matter. In these conference proceedings I discuss the extent to which future ISW measurements can help in precision tests of the physics responsible for the observed cosmic acceleration.
Receiver intermodulation: Enforcing the square law

The mathematics of intermodulation (IM) generation are surveyed, and it is shown that for land mobile receivers, worst case IM is a third-order effect occurring in the first mixer. The importance of relating the IM specification to the receiver sensitivity is pointed out. RF gain reduction or elimination, selectivity at both RF and IF, and the new square law mixing devices are all mentioned as techniques used for receiver IM reduction. The new diodes and field effect transistors are examined in greater detail. Their advantages of low noise and high burnout resistance are contrasted with the problems of conversion gain and high required local oscillator power levels.
The Regge Limit for Green Functions in Conformal Field Theory

We define a Regge limit for off-shell Green functions in quantum field theory, and study it in the particular case of conformal field theories (CFT). Our limit differs from that defined in [32, 33, 34, 35], the latter being only a particular corner of the Regge regime. By studying the limit for free CFTs, we are able to reproduce the Low-Nussinov [39, 40], BFKL [24, 25, 26] approach to the pomeron at weak coupling. The dominance of Feynman graphs where only two high momentum lines are exchanged in the t-channel, follows simply from the free field analysis. We can then define the BFKL kernel in terms of the two point function of a simple light-like bilocal operator. We also include a brief discussion of the gravity dual predictions for the Regge limit at strong coupling.
HIGHWAYS AND ECONOMIC PRODUCTIVITY: INTERPRETING RECENT EVIDENCE

This article reviews the recent literature on public infrastructure and economic productivity, with special attention to the particular case of highway infrastructure. Recent evidence suggests that, at the margin, highway infrastructure contributes little to state or national productivity. This is consistent with studies that show relatively small land-use impacts from modem highways. Yet the idea that highways enhance economic health is common in the policy and planning communities. Two explanations can help reconcile this divergence between academic research and popular perception. First, some of the economic development observed near highways might not actually be caused by the highway. Second, some of the economic development near highways might be a shift of economic activity away from other areas. Either explanation implies the need for reforms in highway project analysis and funding. This article suggests appropriate policy reforms and directions for future research.
Spin and strangeness in the nucleon

Abstract The spin and magnetic moment of the nucleon arise from the quark-gluon constituents and the properties of Quantum Chromodynamics. Over the last decade, the results of spin dependent deep inelastic scattering experiments have indicated that the quark spin contribution is a small fraction of the total spin of the nucleon. This initially surprising result has been interpreted as due to a substantial negative polarization of the strange quark-antiquark sea or as evidence of a sizeable gluon polarization. Further experimental studies are underway to address these issues. The magnetic moment of the nucleon may also contain contributions from strange quarks, and this aspect of nucleon structure is being studied via parity-violating electron scattering. The present status of these experimental efforts and their impact on our knowledge of nucleon structure is discussed.
Frequency dependence of tissue attenuation measured by acoustic microscopy.

Broadband scanning acoustic microscopy (SAM) has been used to investigate the mechanical properties of sections of tissue with a resolution of around 8 μm. The work reported here extends these results by reporting the frequency dependence of the attenuation coefficient from 100–500 MHz. A discussion of the theory of the measurements is presented. The scanning laser acoustic microscope (SLAM) is used to characterize similar tissue sections at 100 MHz. The data obtained with the two forms of acoustic microscopy are compared with results from the literature.
Dictionary Learning and Tensor Decomposition via the Sum-of-Squares Method

We give a new approach to the dictionary learning (also known as "sparse coding") problem of recovering an unknown n x m matrix A (for m ≥ n) from examples of the form [y = Ax + e,] where x is a random vector in Rm with at most τ m nonzero coordinates, and e is a random noise vector in Rn with bounded magnitude. For the case m=O(n), our algorithm recovers every column of A within arbitrarily good constant accuracy in time mO(log m/log(τ-1)), in particular achieving polynomial time if τ = m-δ for any δ>0, and time mO(log m) if τ is (a sufficiently small) constant. Prior algorithms with comparable assumptions on the distribution required the vector $x$ to be much sparser---at most √n nonzero coordinates---and there were intrinsic barriers preventing these algorithms from applying for denser x.We achieve this by designing an algorithm for noisy tensor decomposition that can recover, under quite general conditions, an approximate rank-one decomposition of a tensor T, given access to a tensor T' that is τ-close to T in the spectral norm (when considered as a matrix). To our knowledge, this is the first algorithm for tensor decomposition that works in the constant spectral-norm noise regime, where there is no guarantee that the local optima of T and T' have similar structures.Our algorithm is based on a novel approach to using and analyzing the Sum of Squares semidefinite programming hierarchy (Parrilo 2000, Lasserre 2001), and it can be viewed as an indication of the utility of this very general and powerful tool for unsupervised learning problems.
On D-brane boundary state analysis in pure spinor formalism

We explore a particular approach to study D-brane boundary states in Berkovits' pure spinor formalism of superstring theories. In this approach one constructs the boundary states in the relevant conformal field theory by relaxing the pure spinor constraints. This enables us to write down the open string boundary conditions for non-BPS D-branes in type II string theories, generalizing our previous work in light-cone Green-Schwarz formalism. As a first step to explore how to apply these boundary states for physical computations we prescribe rules for computing disk one point functions for the supergravity modes. We also comment on the force computation between two D-branes and point out that it is hard to make the world-sheet open-closed duality manifest in this computation.
Synthesis of (-)-bullatacin : the enantiomer of a potent, antitumor, 4-hydroxylated, annonaceous acetogenin

Abstract Synthesis of the title compound represents the first construction of any of these potent, antitumor Annonaceous acetogenins with the entire relative stereochemistry in place. Palladium(0)-mediated crossed diyne coupling and the use of three, natural, α-hydroxy acids as the origin of all absolute stereochemistry highlight this flexible approach that sets the stage for access to structural analogs for further study.
The Edge-On Perspective of Bulgeless, Simple Disk Galaxies

This review focuses on flat and superthin galaxies. These are edge-on bulgeless galaxies, which are composed of a simple, stellar disk. The properties of these simple disks are at the end of a continuum that extends smoothly from bulge-dominated disk galaxies to the pure disks. On average, simple disks are low-mass galaxies with low surface brightnesses, blue colors, and slow rotational velocities. Widely-accepted cosmological models of galaxy formation and evolution were challenged by a relatively large observed fraction of pure disk galaxies, and only very recent models can explain the existence of simple disk galaxies. This makes simple disks an optimal galaxy type for the study of galaxy formation in a hierarchical universe. They enable us to analyze the environmental and internal influence on galaxy evolution, to study the stability of the disks, and to explain the nature and distribution of dark matter in galaxies. This review summarizes the current status of edge-on simple disk galaxies in the universe.
Rational curves on holomorphic symplectic fourfolds

Let F be a polarized irreducible holomorphic symplectic fourfold, deformation equivalent to the Hilbert scheme parametrizing length-two zero-dimensional subschemes of a K3 surface. The homology group H^2(F,Z) is equipped with an integral symmetric nondegenerate form, the Beauville form. We give precise conjectures for the structure of the cone of effective curves - and by duality - the cone of ample divisors. Formally they are completely analogous to the results known for K3 surfaces, and they are expressed entirely in terms of the integers represented by the Beauville form restricted to Pic(F). We prove that these conjectures are true in an open subset of the moduli space using deformation theory. The Fano variety of lines contained in a cubic fourfold is an example of a holomorphic symplectic fourfold. Our conjectures imply many concrete geometric statements about cubic fourfolds which may be verified using projective geometry.
Flavor violation in warped extra dimensions and CP asymmetries in B decays

Abstract We show that CP asymmetries in b → s hadronic decays are potentially affected by the presence of massive color–octet particles strongly coupled to the third generation quarks. Theories with warped extra dimensions provide natural candidates in the Kaluza–Klein excitations of gluons in scenarios where flavor-breaking by bulk fermion masses results in the localization of fermion wave-functions. Topcolor models, in which a new gauge interaction leads to top-condensation and a large top mass, also result in the presence of these color–octet states with TeV masses. We find that large effects are possible in modes such as B → φK s , B → η ′ K s and B → π 0 K s among others.
Crustal earthquake bursts in California and Japan: Their patterns and relation to volcanoes

[1] We analyze 153 bursts of earthquakes in southern California and Japan. The burst patterns are similar in southern California and Japan; they fill a spectrum between “swarm-like” sequences without obvious mainshocks and mainshocks with Omori-law-abiding aftershocks. In agreement with our previous work, the “swarm-like” sequences in Japan have more events, are more voluminous, and tend to expand with time, when compared to “mainshock-aftershock” type sequences. In both regions, we find that the sequences starting with their largest events tend to be much shorter in duration. Bursts within 50 km of volcanoes are similar in character to those elsewhere except they tend to have longer duration. We hypothesize that swarminess is a proxy for fluid pressure redistribution and/or aseismic slip driving the seismicity bursts, and conversely, the mainshock-aftershock-style sequences have end-member behavior that results solely from a cascade of elastic failures. The complexity of the spatial seismicity distribution does not correlate with the style of swarm observed, indicating that fluid conditions and composition are likely more influential than geometry in determining the patterns we observe.