cssi/SciSciGPT-SciSciNet huggingface dataset:
Testing models of the individual and cosmological evolutions of powerful radio galaxies

We seek to develop an essentially analytical model for the evolution of Fanaroff-Riley Class II (FR II) radio galaxies as they age individually and as their numbers vary with cosmological epoch. Such modelling is required in order to probe in more detail the impact of radio galaxies on the growth of structures in the Universe, which appears likely to have been quite significant at z > 1. In this first paper of a series we compare three rather sophisticated analytical models for the evolution of linear size and lobe power of FR II radio galaxies, those of Kaiser et al., Blundell et al. and Manolakou & Kirk. We perform multidimensional Monte Carlo simulations in order to compare the predictions of each model for radio powers, sizes, redshifts and spectral indices with data. The observational samples used here are the low-frequency radio surveys, 3CRR, 6CE and 7CRS, which are flux limited and complete. We search for and describe the best parameters for each model, after doing statistical tests on them. We find that no existing model can give acceptable fits to all the properties of the surveys considered, although the Kaiser et al. model gives overall better results than do the Manolakou & Kirk or Blundell et al. models for most of the tests we performed. We suggest ways in which these models may be improved.
An incremental complementary energy method of nonlinear stress analysis

A stress analysis capability to treat orthotropic physically nonlinear materials that behave differently in tension and compression is presented. The analysis is an energy search method based on an incremental complementary energy formulation. Load incrementation is used. Stress solutions are obtained by formulating and minimizing the incremental complementary energy associated with each load increment. Material behavior is conservative during each load increment. Structures are idealized as an assemblage of discrete elements. An Airy stress function is approximated by a sum of unknown coefficients times interpolation polynomials for each element. Equilibrium between adjacent elements is satisfied identically by imposing equality constraints on the unknown coefficients. Applications to structural elements loaded in plane stress or plane strain are presented. Correlations with some experimental results available in the literature are made.
Symbolic computer algebra algorithms for factorizations of Sylvester mappings with applications to the production of linear matrix inequalities in systems and controls

We describe theory and algorithms that can be used to factor polynomial matrices in noncommuting variables with applications to the conversion of problems in systems and controls into linear matrix inequalities.
The Influence of the Solar Cycle and QBO on the Late-Winter Stratospheric Polar Vortex

Abstract A statistical analysis of 51 years of NCEP–NCAR reanalysis data is conducted to isolate the separate effects of the 11-yr solar cycle (SC) and the equatorial quasi-biennial oscillation (QBO) on the Northern Hemisphere (NH) stratosphere in late winter (February–March). In a four-group [SC maximum (SC-max) versus minimum (SC-min) and east-phase versus west-phase QBO] linear discriminant analysis, the state of the westerly phase QBO (wQBO) during SC-min emerges as a distinct least-perturbed (and coldest) state of the stratospheric polar vortex, statistically well separated from the other perturbed states. Relative to this least-perturbed state, the SC-max and easterly QBO (eQBO) each independently provides perturbation and warming as does the combined perturbation of the SC-max–eQBO. All of these results (except the eQBO perturbation) are significant at the 95% confidence level as confirmed by Monte Carlo tests; the eQBO perturbation is marginally significant at the 90% level. This observational res...
Future CO2 Emissions and Climate Change from Existing Energy Infrastructure

Slowing climate change requires overcoming inertia in political, technological, and geophysical systems. Of these, only geophysical warming commitment has been quantified. We estimated the commitment to future emissions and warming represented by existing carbon dioxide–emitting devices. We calculated cumulative future emissions of 496 (282 to 701 in lower- and upper-bounding scenarios) gigatonnes of CO 2 from combustion of fossil fuels by existing infrastructure between 2010 and 2060, forcing mean warming of 1.3°C (1.1° to 1.4°C) above the pre-industrial era and atmospheric concentrations of CO 2 less than 430 parts per million. Because these conditions would likely avoid many key impacts of climate change, we conclude that sources of the most threatening emissions have yet to be built. However, CO 2 -emitting infrastructure will expand unless extraordinary efforts are undertaken to develop alternatives.
Ruthenium-catalyzed stereospecific decarboxylative allylation of non-stabilized ketone enolates.

The ruthenium-catalyzed stereospecific decarboxylative allylation of ketone enolates provides access to γ,δ-unsaturated ketones with good yields and enantioenrichments.
Evaluation of a new concept for reducing free-stream turbulence in wind tunnels

The feasibility of using a 45 deg-honeycomb for improving the flow quality in wind tunnels was investigated. The results of the experiments indicate that the turbulence levels in a wind tunnel using the 45 deg-honeycomb would be comparable to those obtainable using a conventional honeycomb, i.e., a honeycomb which is positioned normal to the mean flow in the settling chamber. However, this is true only when a 45 deg-screen is mounted immediately downstream of the honeycomb, and when some distance is provided between the trailing edges of the corner turning vanes and the upstream side of the 45 deg-honeycomb. This distance is required for adequate decay of the turning-vane wakes, thereby providing a reasonably uniform mean flow entering the honeycomb. Results demonstrate that this distance should be at least twice the spacing between the turning vanes. Even though the resulting turbulence intensity is the same downstream of both the 45 deg-honeycomb and the conventional honeycomb, there would have to be a significant improvement in the test-section turbulence intensity using the 45 deg-honeycomb to justify the additional expense in fabricating and installing this type of honeycomb.
Theoretical Study of Base-Catalyzed Amide Hydrolysis: Gas- and Aqueous-Phase Hydrolysis of Formamide

Base-catalyzed hydrolysis of formamide in the gas phase and in aqueous solution has been studied using a combination of quantum chemical and statistical mechanical methods. A three-step procedure has been applied which comprises the determination of a gas-phase reaction path by high-level ab initio calculations, the calibration of empirical solute−solvent potentials, and classical Monte Carlo simulations of the solute immersed in a bath of solvent molecules. These simulations yield the solvent effect as a potential of mean force along the predetermined reaction coordinate. Each of the three consecutive steps of base-catalyzed hydrolysis has been analyzed in detail: the formation of a tetrahedral intermediate, its conformational isomerization, and the subsequent breakdown to products. The reaction is very exothermic in the gas phase and involves only moderate barriers for the latter two steps. Aqueous solvent, however, induces a significant barrier toward formation of the intermediate. On the other hand, ...
Approximate sorting of data streams with limited storage

We consider the problem of approximate sorting of a data stream (in one pass) with limited internal storage where the goal is not to rearrange data but to output a permutation that reflects the ordering of the elements of the data stream as closely as possible. Our main objective is to study the relationship between the quality of the sorting and the amount of available storage. To measure quality, we use permutation distortion metrics, namely the Kendall tau, Chebyshev, and weighted Kendall metrics, as well as mutual information, between the output permutation and the true ordering of data elements. We provide bounds on the performance of algorithms with limited storage and present a simple algorithm that asymptotically requires a constant factor as much storage as an optimal algorithm in terms of mutual information and average Kendall tau distortion. We also study the case in which only information about the most recent elements of the stream is available. This setting has applications to learning user preference rankings in services such as Netflix, where items are presented to the user one at a time.
In situ formation and reaction of 2-pyridylboronic esters

Abstract 2-Pyridylboronic esters were generated by cross-coupling 2-bromopyridines with bis(pinacolato)diboron in the presence of a base and palladium catalyst. The boronic esters reacted in situ with unreacted 2-bromopyridines to afford high yields of 2,2′-bipyridines as homocoupled products. Depending upon the reaction conditions, varying amounts of protodeboronated products were also observed. An attempted cross-coupling between two different 2-bromopyridines produced a nearly statistical mixture of homo- and cross-coupled products.
Analyzed Binary Computing

A single format for the representation of numbers in a computer is proposed to accommodate both exact and inexact quantities. A consistent set of rules is described for addition (subtraction), multiplication, and division of such quantities, both within their separate types, as well as in combination. Error correlation aside, the propagation of inherent errors is monitored in operations with at least one imprecise value. A definitive algorithm must, of course take into account any correlations of inherent errors; these correlations must be recognized and incorporated into the algorithm by the numerical analyst, not by the logical designer of the computer.
The generating hypothesis in the derived category of R-modules

Abstract In this paper, we prove a version of Freyd’s generating hypothesis for triangulated categories: if D is a cocomplete triangulated category and S ∈ D is an object whose endomorphism ring is graded commutative and concentrated in degree zero, then S generates (in the sense of Freyd) the thick subcategory determined by S if and only if the endomorphism ring of S is von Neumann regular. As a corollary, we obtain that the generating hypothesis is true in the derived category of a commutative ring R if and only if R is von Neumann regular. We also investigate alternative formulations of the generating hypothesis in the derived category. Finally, we give a characterization of the Noetherian stable homotopy categories in which the generating hypothesis is true.
INDUSTRY EFFECTS OF ANALYST STOCK REVISIONS

We examine the industry valuation effects of analyst stock revisions and identify the variables that influence these effects. Our results show that industry rivals experience significant abnormal returns in response to revision announcements. Although the mean stock price response suggests contagion effects, there is also evidence of significant competitive effects. The valuation effects are influenced by the magnitude of the rated firm's announcement return, along with analyst-specific and industry-specific characteristics. However, the sensitivity of the valuation effects to these characteristics is conditioned on whether the industry effects are contagious or competitive.
“Fit to Enter the World”: Hannah Arendt on Politics, Economics, and the Welfare State

What is the significance of the welfare state and struggles over social and economic needs for democratic politics? This article turns to Hannah Arendt's thought to articulate new possibilities for relating democratic agency and the welfare state, possibilities neglected by currently dominant deliberative and radical democratic approaches. Against critics who claim that Arendt seeks to purify politics of economic and social problems, I argue that she presents a sophisticated account of the vital importance of economic matters for public life. For Arendt, the danger is not the invasion of politics by economics, but rather the loss of the worldly, mediating institutions that allow economic matters to appear as objects of public concern. Reconstructing her account of these mediating institutions, I show that Arendt's analysis opens up novel insights into the relationship between democratic action and welfare institutions, drawing attention to how such institutions transform material necessity into shared objects of attachment, judgment, and action.
The operating system kernel as a secure programmable machine

To provide modularity and performance, operating system kernels should have only minimal embedded functionality. Today's operating systems are large, inefficient and, most importantly, inflexible. In our view, most operating system performance and flexibility problems can be eliminated simply by pushing the operating system interface lower. Our goal is to put abstractions traditionally implemented by the kernel out into user-space, where user-level libraries and servers abstract the exposed hardware resources. To achieve this goal, we have defined a new operating system structure, exokernel, that safely exports the resources defined by the underlying hardware. To enable applications to benefit from full hardware functionality and performance, they are allowed to download additions to the supervisor-mode execution environment. To guarantee that these extensions are safe, techniques such as code inspection, inlined cross-domain procedure calls, and secure languages are used. To test and evaluate exokernels and their customization techniques a prototype exokernel, Aegis, is being developed.
Beyond TPPTS: New Approaches to the Development of Efficient Palladium‐Catalyzed Aqueous‐Phase Cross‐Coupling Reactions

Water is an attractive solvent for metal-catalyzed reactions with both economic and environmental sustainability benefits. In addition, the use of a hydrophilic catalyst in an aqueous-biphasic solvent system provides the opportunity to easily recover, and potentially recycle, the catalyst species. The feasibility of cross-coupling reactions catalyzed by hydrophilic palladium catalysts was first demonstrated using sulfonated analogs of triphenylphosphane, such as tris(3-sulfonatophenyl)phosphane trisodium salt (TPPTS). Catalysts derived from TPPTS and other structurally similar hydrophilic phosphanes are generally effective only with aryl iodides and activated aryl bromides. This microreview will focus on more recently developed hydrophilic ligands with increased steric demand and electron-donating abilities that are effective in coupling reactions of aryl bromides and chlorides under mild conditions in aqueous solvents. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
High gradient superconducting niobium cavities. A review of the present status

Superconducting niobium cavities used in particle accelerators are limited in their RF performance by two phenomena: quench field levels below the theoretical limit of the material caused by defects; and field emission loading resulting from artificial contamination of the superconducting surfaces during surface treatment and assembly procedures. In recent years, the community involved in SRF technology developments has successfully improved cavity performances by applying advanced surface treatment methods such as chemical polishing, electropolishing, tumbling, high temperature heat treatment, high pressure rinsing, "in situ" high peak power processing and clean room assembly procedures. In addition, improvements in the material properties such as thermal conductivity by "solid state gettering" and very strict QA methods, both in material inspection and during cavity fabrication, have resulted in cavity performance levels of E/sub acc/ up to 40 MV/m in monocells and gradients in the vicinity of 30 MV/m in multicell structures at Q-values of /spl ap/10/sup 10/ at a temperature of 2 K. More recently, the fabrication of "seamless" cavities by spinning is being pursued with encouraging results. This process eliminates electron beam welds, which sometimes are the cause of performance degradations.
Lower fat and better quality diet therapy for children with pharmacoresistant epilepsy

The ketogenic diet (KD) is an established, effective, nonpharmacologic treatment for children with pharmacoresistant epilepsy. Although the KD is the most well-established dietary therapy for epilepsy, it is too restrictive and is associated with serious complications; therefore, alternative lower-fat diets, including a modified Atkins diet and low-glycemic index diet, have been developed. Recent ongoing clinical evidence suggests that other dietary therapies have an efficacy almost comparable to that of the KD. In addition, a diet rich in polyunsaturated fatty acids appears to increase the efficacy of diet therapy and reduce the complications of a high-fat diet. Here, we review the systematic information about lower-fat diets and better-quality dietary therapies and the current clinical status of each of these dietary approaches.
INTERNISTS OF THE MIND OR PHYSICIANS OF THE SOUL: DOES PSYCHIATRY NEED A PUBLIC PHILOSOPHY?

. Although psychiatry is interested in what both body and mind contribute to behavior, it sometimes emphasizes one more than the other. Since the early 1980s, American psychiatry has shifted its interest from mind and psyche to body and brain. Neuroscience and psychopharmacology are increasingly at the core of psychiatry. Some experts claim that psychiatry is no longer interested in problems in living and positive goals such as mental health, happiness, and morality but rather has narrowed its focus to mental disorders addressed with psychotropic drugs. In view of this trend, psychiatry needs to confront two questions in social philosophy. If it is no longer directly concerned with health and happiness, how does it relate to these positive goals? And how does it relate as a medical institution to religious institutions, schools, and other organizations that directly promote health, happiness, morality, and the purposes of life? It is not enough for psychiatry to renounce its moral role; its practices still shape cultural values. Psychiatry should take more responsibility for developing a public philosophy that addresses these issues.
The clinical voice laboratory: Clinical application of voice research

Summary In the past decade the number of voice laboratories has increased dramatically. Their primary mission is to enhance patient care by the application of knowledge gained from basic research. They also are dedicated to further improvement of diagnostic and therapeutic resources. The strength of the voice laboratory lies in collaboration between the clinician and the scientist.
Safety Profile of IBD: Lymphoma Risks

This article describes the cancer risks of commonly used inflammatory bowel disease (IBD) medications, with an emphasis on hematologic malignancy risks. The increasing use of immunosuppressant therapies in the treatment of IBD has raised this question to an even greater importance. Studies evaluating these medications are complicated due to varying disease severity and concomitant use of other immunosuppressant medication. The potential risks of all therapies must be weighed against the benefits these therapies can offer these patients.
A quantum mechanically guided view of Mg44Rh7.

We present a new geometric description of Mg 44 Rh 7 , a compound with 408 atoms in its cubic unit cell. Using both experimental site preferences and LDA-DFT-calibrated extended Huckel (eH) calculations as guides, we highlight the structural units within Mg 44 Rh 7 that reflect the electron-richness or electron-poorness of each crystallographic site. The units that best account for these site preferences and electron populations are 34- and 25-atom fragments of the Ti 2 Ni structure, rather than the variety of clusters often used to describe complicated intermetallic and ionic structures. These Ti 2 Ni pieces, located using a systematic search algorithm, fit together in a beautifully intricate network. An examination of this network reveals some surprising geometric features of Mg 44 Rh 7 , including a fractal-like arrangement of similar atomic formations on different length scales, geometrically connected to an approximate fivefold symmetry.
A Case Study of Carbon Sequestration Potential of Land Use Policies Favoring Re-growth and Long-term Protection of Temperate Forests

There is a traditional view suggesting forests remove carbon dioxide from the atmosphere (Pregitzer & Euskirchen, 2004), but they cease to serve as a carbon sink as they fully mature (Odum, 1969). Recent modeling of old-growth forest carbon sequestration indicate they continue to serve as a “net sink” of carbon even after maturity (Carey, Sala, Keane, & Callaway, 2001; Zhou et al., 2006) - sequestering an average of 2.4 +/- 0.8 tC ha -1 yr -1 (tC = metric tons of carbon; ha = hectare; yr =year), and yielding a ratio of heterotrophic respiration (Rh) to net primary production (NPP) of approximately 0.65 +/- 0.02 (Luyssaert et al., 2008). These figures show the strongest correlation amongst temperate forest regions. Two calculations are made using this carbon sequestration average. One is made identifying the amount of carbon sequestered through a small-scale land protection organization, yielding a net carbon sequestration of approximately 224 metric tons of carbon per year. The other is based on the amount of land required to offset current anthropogenic emissions of carbon in the global carbon budget, showing approximately 235 million hectares of new forest growth would be required to offset current global anthropogenic emissions. One implication of these calculations is the traditional assumption of carbon neutrality increasing with age (Magnani et al., 2007) is incorrect, suggesting mature forest protection may be a favored policy choice for carbon sequestration strategies.
Temperature dependence of the nuclear symmetry energy

Abstract We have studied the properties of various isobars with 54 ≤ A ≤ 64 for temperatures T ≤ 1.2 MeV via Monte Carlo shell model calculations with the KB3 interaction. In accord with empirical indications, we find no systematic temperature dependence of the symmetry energy coefficient, b sym , for T ≤ 1 MeV. This contradicts a recent suggestion that b sym increases by 2.5 MeV at this temperature, which would significantly alter the supernova explosion scenario.
An Experiment in Architectural Instruction

The College of Architecture at the University of Arizona uses the Plato computer to teach freshman basic drawing skills. The purpose of this paper is to describe how computer-aided instruction was designed and used in the Graphics Communications class and to relate the students' reaction to this experience.
Knowledge Acquisition for ATE Diagnosis

An applied intelligence program for ATE fault diagnosis shows promise as an effective method to reduce mean time to repair (MTTR). The types of knowledge required by an intelligent diagnostic for VLSI test systems, the resources needed to derive that knowledge, the approach implemented to organize it, and the final form of the knowledge representations which resulted from our work are discussed in this paper.
The analysis of contingency tables

Contingency tables and the chi-square test.- 2 x 2 Contingency tables.- r x c Contingency tables.- Multidimensional tables.- Log-linear models for contingency tables.- Some special types of contingency table.
A Model for the Formation of High-Density Clumps in Proto-Planetary Nebulae

The detection of NaCl at large radii in the Egg Nebula, CRL 2688, requires densities of 10 7 –10 8 cm 3 in a thick shell of r ∼ af ew# 10 17 cm. To explain these results, a mechanism is needed for producing high densities at a considerable distance from the central star. In two-dimensional simulations of the interaction of the fast wind with an ambient medium, the material becomes thermally unstable. The resulting clumps can achieve the requisite conditions for NaCl excitation. We present two-dimensional models with simple physics as proof-of-principle calculations to show that the clumping behavior is robust. Clumping is a natural outcome of cooling in the colliding wind model and comparable to that inferred from observations. Subject headings: astrochemistry — hydrodynamics — stars: AGB and post-AGB — stars: winds, outflows
Internet-based teleoperation using wave variables with prediction

Wave-based teleoperation has been previously attempted over the Internet, however, performance rapidly deteriorates with increasing delay. This paper focuses on the use of a modified Smith predictor, a Kalman filter and an energy regulator to improve the performance of a wave-based teleoperator. This technique is further extended for use over the Internet, where the time delay is varying and unpredictable. It is shown that the resulting system is stable even if there are large uncertainties in the model of the remote system (used in prediction). Successful experimental results using this technique for teleoperation in a master-slave arrangement over the Internet, where the control signal is streamed between Atlanta (Georgia) and Tokyo (Japan), are also given.
Currents on generalized Yagi structures

Characteristics of currents produced on an infinite linear array of parasitic radiators when one of the radiators is excited are found. Yagi antennas use arrays of electric dipoles; detailed analyses and results are given for a generalized Yagi structure in which the dipoles are inclined at an arbitrary, angle to the array axis. These results suggest a simple mechanical means for broadbanding. Calculations are carried out within a network formulation. The integral solution obtained from this formulation is used to demonstrate the interrelation between the properties of the array of radiators excited parasitically or excited as a phased array. The solution simplifies remarkably when the angle of inclination of the dipoles is 54.74\deg . The surface-wave components and the (feed) correction currents are then explicitly evaluated. Although for conventional Yagi structures surface-wave solutions have been found only for capacitive dipoles, for sufficiently small angles of inclination surface waves can exist on arrays of inductive dipoles.
Optical and near-infrared spectroscopy of a high-redshift, hard x-ray emitting spiral galaxy

We present optical and near-infrared Keck spectroscopy of CXOHDFN J123635.6+621424 (HDFX 28), a hard X-ray source at a redshift of z = 2.011 in the flanking fields of the Hubble Deep Field North (HDF-N). HDFX 28 is a red source (R-Ks = 4.74) with extended steep-spectrum (α GHz > 0.87 GHz) microjansky radio emission and significant emission (441 μJy) at 15 μm. Accordingly, initial investigations prompted the interpretation that HDFX 28 is powered by star formation. Subsequent Chandra imaging, however, revealed hard (Γ = 0.30) X-ray emission indicative of absorbed active galactic nucleus (AGN) activity, implying that HDFX 28 is an obscured type II AGN. The optical and near-infrared spectra presented herein corroborate this result; the near-infrared emission lines cannot be powered by star formation alone, and the optical emission lines indicate a buried AGN. HDFX 28 is identified with a face-on moderately late-type spiral galaxy. Multiwavelength morphological studies of the HDF-N have heretofore revealed no galaxies with any kind of recognizable spiral structure beyond z > 2. We present a quantitative analysis of the morphology of HDFX 28, and we find the measures of central concentration and asymmetry to be indeed consistent with those expected for a rare high-redshift spiral galaxy.
Whither California Agriculture: Up, Down, or Out? Some Thoughts about the Future

The turn of the millennium was marked by hard times in California agriculture: low prices seemingly across the board, water-supply woes, contracting growth in export markets, more stringent regulatory environments, and declining farm income. The report begins by pondering several questions: “Is it as bleak as it sounds?” “California agriculture has experienced recurrent challenges over its history and survived—can it do so again?” “Will it be able to adjust and grow in the twenty-first century?” Major portions of the report include a stylized history of California agriculture from 1769 to 2000, identification of twenty important historical drivers influencing its evolution through the end of the twentieth century, and an assessment of changes likely to influence the future of California agriculture over the next half century. The chapters are as follows: I. Introduction * Direct and Indirect Indicators of a “Turn of the Century” Problem? * External/Indirect Factors * Consequences for California Agriculture II. A Stylized History of California Agriculture from 1769 to 2000 * Pre-20th Century Epochs * Epochs of the First Half of the 20th Century * Epochs of the Second Half of the 20th Century * At Century’s End III. The Changing Structure of California Agriculture, Statistics, and Financial Indicators: 1950–2000 * The Changing Character of California Agriculture: 1950–2000 * Agricultural Exports * Selected Farm Statistics: 1950–2000 * Summary IV. Drivers of California Agriculture * Factors (Drivers) Influencing Evolution of California Agriculture—Past * Future Threats and/or Future Opportunities * Drivers Influencing the Future of California Agriculture * Concluding Comment: Factors Affecting the Future of * California’s Agriculture V. A Possible Prognosis for the Future * Why California Agriculture Is Different * Bottom Line: What Are California Agriculture’s Chances? * Bottom-Bottom Line VI. References VII. Appendix
THE X-RAY VARIABILITY OF A LARGE, SERENDIPITOUS SAMPLE OF SPECTROSCOPIC QUASARS

We analyze the X-ray variability of 264 Sloan Digital Sky Survey spectroscopic quasars using the Chandra public archive. This data set consists of quasars with spectroscopic redshifts out to z Almost-Equal-To 5 and covers rest-frame timescales up to {Delta}t{sub sys} Almost-Equal-To 2000 days, with three or more X-ray observations available for 82 quasars. It therefore samples longer timescales and higher luminosities than previous large-scale analyses of active galactic nucleus (AGN) variability. We find significant ({approx}>3{sigma}) variation in Almost-Equal-To 30% of the quasars overall; the fraction of sources with detected variability increases strongly with the number of available source counts up to Almost-Equal-To 70% for sources with {>=}1000 counts per epoch. Assuming that the distribution of fractional variation is Gaussian, its standard deviation is Almost-Equal-To 16% on {approx}>1 week timescales, which is not enough to explain the observed scatter in quasar X-ray-to-optical flux ratios as being due to variability alone. We find no evidence in our sample that quasars are more variable at higher redshifts (z > 2), as has been suggested in previous studies. Quasar X-ray spectra vary similarly to some local Seyfert AGNs in that they steepen as they brighten, with evidence for a constant, hard spectral component thatmore » is more prominent in fainter stages. We identify one highly variable Narrow Line Seyfert 1-type spectroscopic quasar in the Chandra Deep Field-North. We constrain the rate of kilosecond-timescale flares in the quasar population using Almost-Equal-To 8 months of total exposure and also constrain the distribution of variation amplitudes between exposures; extreme changes (>100%) are quite rare, while variation at the 25% level occurs in <25% of observations. [O III] {lambda}5007 A emission may be stronger in sources with lower levels of X-ray variability; if confirmed, this would represent an additional link between small-scale (corona) and large-scale (narrow-line region) AGN properties.« less
Design, Synthesis, and Properties of Molecule-Based Assemblies with Large Second-Order Optical Nonlinearities

The design, synthesis, characterization, and understanding of new molecular and macromolecular assemblies with large macroscopic optical nonlinearities represents an active field of research at the interface of modern chemistry, physics, and materials science. Challenges in this area of photonic materials typify an important theme in contemporary chemistry: to create new types of functional materials by the rational construction of supramolecular assemblies exhibiting preordained collective phenomena by virtue of “engineered” molecule–molecule interactions and spatial relationships. This review surveys several approaches to, and the microstructural and optical properties of, second-order nonlinear optical materials built from noncentrosymmetric assemblies of chromophores having large molecular hyperpolarizabilities. Such types of materials can efficiently double the frequency of incident light, exhibit other second-order nonlinear optical effects, and contribute to the knowledge base needed for new photonic device technologies. Systems described include chromophore macromolecule guesthost matrices, chromophore-functionalized glassy macromolecules, thermally crosslinked chromophore-macromolecule matrices, and intrinsically acentric self-assembled chromophoric superlattices.
X-RAY EMISSION FROM THE WEAK-LINED T TAURI BINARY SYSTEM KH 15D

The unique eclipsing, weak-lined T Tauri star KH 15D has been detected as an X-ray source in a 95.7 ks exposure from the Chandra X-Ray Observatory archives. A maximum X-ray luminosity of 1.5 × 1029 ergs s-1 is derived in the 0.5-8 keV band, corresponding to LX/Lbol = 7.5 × 10-5. Comparison with samples of stars of similar effective temperature in NGC 2264 and in the Orion Nebula cluster shows that this value is about an order of magnitude lower than that for a typical star of its mass and age. We argue that the relatively low luminosity cannot be attributed to absorption along the line of sight but implies a real deficiency in X-ray production. Possible causes for this are considered in the context of a recently proposed eccentric binary model for KH 15D. In particular, we note that the visible component rotates rather slowly for a weak-lined T Tauri star and has possibly been pseudosynchronized by tidal interaction with the primary near periastron.
Line-drawing interpretation: bilateral symmetry

Results previously derived by the author are used to investigate the implication of bilateral symmetry in line drawings. It is shown that the line drawing of an orthographically protected surface of revolution exhibits bilateral symmetry about the projection of its axis of revolution irrespective of the viewing direction. Barring one exception, a bilaterally symmetric line drawing is necessarily the orthographic projection of a local surface of revolution whenever its symmetry axis continues to be the projection of a fixed line in space under perturbation of viewpoint; the axis of revolution is the invariant preimage of the symmetry axis. Various line-drawing causes are detailed which facilitate the deduction of invariant preimages of symmetry axes, and consequently of local surfaces of revolution. >
Amine α-heteroarylation via photoredox catalysis: a homolytic aromatic substitution pathway

The direct α-heteroarylation of tertiary amines has been accomplished via photoredox catalysis to generate valuable benzylic amine pharmacophores. A variety of five- and six-membered chloroheteroarenes are shown to function as viable coupling partners for the α-arylation of a diverse range of cyclic and acyclic amines. Evidence is provided for a homolytic aromatic substitution mechanism, in which a catalytically-generated α-amino radical undergoes direct addition to an electrophilic chloroarene.
Emergent management of multisystem injuries by a general trauma surgeon

Abstract Objective: To determine the requisite education and scope of practice for a general surgeon trained to deliver emergent trauma care without the need for specialty consultation. Design: Retrospective case review. Setting: Private Level I trauma center. Patients: 4097 trauma patients admitted between 1/1/92 and 30/6/97. Main outcome measures: Mechanisms of injury; operations (total within the first 24 h) by mechanism and by surgical specialty. Results: Of 4097 trauma patients, 1086 (27%) underwent 1772 operative procedures within 24 h of admission, and 246 (6%) underwent 484 later operations. Orthopaedic and general surgical procedures were most common (51% of early operations). Early operations were most commonly orthopaedic for blunt trauma and general surgical for penetrating trauma. Although 685 patients (16.7%) received neurosurgical evaluation, only 150 early operations were performed (8% of the total early operations). At least 1244 procedures (55%) fell within the scope of current trauma general surgical practice advocated by some authorities. Conclusions: The contribution of the various specialties to early operative trauma management is a function of the injury mechanism. As orthopaedics and neurosurgery together comprise 34% of emergency practice, a fully credentialed general surgeon with additional training in these disciplines could perform up to 90% of early operations.
The Creation of Spectral Gaps by Graph Decoration

We present a mechanism for the creation of gaps in the spectra of self-adjoint operators defined over a Hilbert space of functions on a graph, which is based on the process of graph decoration. The resulting Hamiltonians can be viewed as associated with discrete models exhibiting a repeated local structure and a certain bottleneck in the hopping amplitudes.
Modeling Spatial Accessibility within Discrete Choice Framework

Modeling Spatial Accessibility within Discrete Choice Framework John M. Ulimwengu and Xiaoqi Guo Authors are Graduate Research Associates in the Department of Agricultural, Environmental, and Development Economics, Ohio State University Contact Information: Department of Agricultural, Environmental, and Development Economics, Ohio State University; 2120 Fyffe Road, Columbus, OH, 43210 Ulimwengu.1@osu.edu and guo.63@osu.edu Selected Paper prepared for the presentation at the American Agricultural Economics Association Annual Meeting, Denver, Colorado, August 1-4, 2004 Copyright 2004 by John M. Ulimwengu and Xiaoqi Guo. All rights reserved. Readers may make verbatim copies of this document for non-commercial purposes by any means, provided that this copyright notice appears on all copies.
THE STRATEGY CONFIGURATION OF CHINESE SMEs

This paper investigates how Chinese SMEs configure marketing, cost-control, and innovation strategies in order to attain better organizational effectiveness. Rather than the more standard approach of suggesting that SMEs focus exclusively on one strategy, we hypothesize that when a strategy configuration is composed of multiple prioritized and related strategies, organizational effectiveness will be improved. Data collected from 133 small and medium-sized Chinese SMEs verified our hypotheses. The implications of our study for Chinese SMEs, China's policy makers, and overseas investors are discussed.
p-torsion elements in local cohomology modules

For every prime integer p, M. Hochster conjecturedthe existence of certain p-torsion elements in a local cohomology module over a regular ring of mixedcharacteristic. We show that Hochster's conjecture is false. We next con- struct an example where a local cohomology module over a hypersurface has p- torsion elements for every prime integer p, andconsequently has infinitely many associatedprime ideals. For a commutative Noetherian ring R and an ideal a ⊂ R, the finiteness properties of the local cohomology modules H i
Optimization of Starburst99 for Intermediate-Age and Old Stellar Populations

We have incorporated the latest release of the Padova models into the evolutionary synthesis code Starburst99. The Padova tracks were extended to include the full asymptotic giant branch (AGB) evolution until the final thermal pulse over the mass range 0.9-5 M☉. With this addition, Starburst99 accounts for all stellar phases that contribute to the integrated light of a stellar population with arbitrary age from the extreme-ultraviolet to the near-infrared. AGB stars are important for ages between 0.1 and 2 Gyr, with their contribution increasing at longer wavelengths. We investigate similarities and differences between the model predictions by the Geneva and the Padova tracks. The differences are particularly pronounced at ages >1 Gyr, when incompleteness sets in for the Geneva models. We also perform detailed comparisons with the predictions of other major synthesis codes and find excellent agreement. Our synthesized optical colors are compared to observations of old, intermediate-age, and young populations. Excellent agreement is found for the old globular cluster system of NGC 5128 and for old and intermediate-age clusters in NGC 4038/4039. In contrast, the models fail for red supergiant-dominated populations with subsolar abundances. This failure can be traced back to incorrect red supergiant parameters in the stellar evolutionary tracks. Our models and the synthesis code are publicly available as version 5.0 of Starburst99 at http://www.stsci.edu/science/starburst99.
Polystyrene-Supported Triphenylsilyl Chloride for the Silylation-Based Kinetic Resolution of Secondary Alcohols

A silyl chloride derivatized styrene polymer was employed in the silylation-based kinetic resolution of secondary alcohols for chromatography-free separation of alcohol enantiomers. Synthetically useful selectivity factors were obtained; furthermore, the polymer was recycled for use in a subsequent kinetic resolution, and it maintained its selectivity and integrity.
Mod 2 cohomology of combinatorial Grassmannians

Matroid bundles, introduced by MacPherson, are combinatorial analogues of real vector bundles. This paper sets up the foundations of matroid bundles. It defines a natural transformation from isomorphism classes of real vector bundles to isomorphism classes of matroid bundles. It then gives a transformation from matroid bundles to spherical quasifibrations, by showing that the geometric realization of a matroid bundle is a spherical quasifibration. The poset of oriented matroids of a fixed rank classifies matroid bundles, and the above transformations give a splitting from topology to combinatorics back to topology. A consequence is that the mod 2 cohomology of the poset of rank k oriented matroids (this poset classifies matroid bundles) contains the free polynomial ring on the first k Stiefel-Whitney classes.
Direct Formation and Reactions of Allylic Thienyl-Based Organocopper Reagents

Abstract The lithium naphthalenide reduction of lithium 2-thienylcyanocuprate produces a highly reactive zero-valent copper complex. This allows for the direct formation of allylic organocopper reagents and ensuing cross-couplings with electrophiles.
Mod-2 wind-turbine field-operations experience

The Mod-2 wind-turbine project is a development and research test operations programme sponsored by the US Department of Energy (Office of Solar Electric Technologies), managed by the NASA Lewis Research Center. The development of the turbine was initiated in 1977 under a contract which NASA awarded to the Boeing Engineering Company (now Boeing Aerospace Co.). The three-machine, 7.5 MW Goodnoe Hills cluster, located near Goldendale, Washington, is now in a research/experimental operations phase that offers a unique opportunity to study the effects of single and multiple wind turbines interacting with each other, the power grid and the environment. Following a brief description of the turbine and project history, the paper addresses major problem areas and research and development test results. Field operations, both routine and nonroutine, are discussed. Routine operation to date has produced over 13 379 000 kWh of electrical energy during 11 064 h of rotation. Nonroutine operation includes suspended activities caused by a crack in the low-speed shaft that necessitated a redesign and reinstallation of this assembly on all three turbines. With the world's largest cluster back in full operation, two of the turbines will be operated over the next several years to determine their value as energy producers. The third unit will be used primarily for conducting research tests requiring configuration changes to better understand the wind-turbine technology. Technical areas summarised in the paper pertain to system performance and enhancements. Specific research tests relating to acoustics, TV interference and wake effects conclude the paper.
Aeroheating Environments for a Mars Smart Lander

A proposed Mars Smart Lander is designed to reach the surface via lifting-body atmospheric entry (alpha = 16 deg) to within 10 km of the target site. CFD (computational fluid dynamics) predictions of the forebody aeroheating environments are given for a direct entry from a 2005 launch. The solutions were obtained using an 8-species gas in thermal and chemical nonequilibrium with a radiative-equilibrium wall temperature boundary condition. Select wind tunnel data are presented from tests at NASA Langley Research Center. Turbulence effects are included to account for both smooth body transition and turbulence due to heatshield penetrations. Natural transition is based on a momentum-thickness Reynolds number value of 200. The effects of heatshield penetrations on turbulence are estimated from wind tunnel tests of various cavity sizes and locations. Both natural transition and heatshield penetrations are predicted to cause turbulence prior to the nominal trajectory peak heating time. Laminar and turbulent CFD predictions along the trajectory are used to estimate heat rates and loads. The predicted peak turbulent heat rate of 63 W/sq cm on the heatshield leeward flank is 70% higher than the laminar peak. The maximum integrated heat load for a fully turbulent heat pulse is 38% higher than the laminar load on the heatshield nose. The predicted aeroheating environments with uncertainty factors will be used to design a thermal protection system.
Convergence Analysis of Reweighted Sum-Product Algorithms

Markov random fields are designed to represent structured dependencies among large collections of random variables, and are well-suited to capture the structure of real-world signals. Many fundamental tasks in signal processing (e.g., smoothing, denoising, segmentation etc.) require efficient methods for computing (approximate) marginal probabilities over subsets of nodes in the graph. The marginalization problem, though solvable in linear time for graphs without cycles, is computationally intractable for general graphs with cycles. This intractability motivates the use of approximate ldquomessage-passingrdquo algorithms. This paper studies the convergence and stability properties of the family of reweighted sum-product algorithms, a generalization of the widely used sum-product or belief propagation algorithm, in which messages are adjusted with graph-dependent weights. For pairwise Markov random fields, we derive various conditions that are sufficient to ensure convergence, and also provide bounds on the geometric convergence rates. When specialized to the ordinary sum-product algorithm, these results provide strengthening of previous analyses. We prove that some of our conditions are necessary and sufficient for subclasses of homogeneous models, but not for general models. The experimental simulations on various classes of graphs validate our theoretical results.
Empire is in the details

Recent writing that identifies the United States as an empire has focused overwhelmingly on its political-economic underpinnings, without questioning the cultural making of value or examining empire as more than an elite project. This writing has not drawn on ethnographic work that would reshape it in more adequate, less economistic forms, make the human face and frailties of imperialism more visible, and, in so doing, make challenges to imperial practice more likely. Focusing on military institutions, and via some examples from U.S. imperial projects in the Philippines and elsewhere, I suggest where ethnographies of empire might be done and what vulnerabilities they might explore.