cssi/SciSciGPT-SciSciNet huggingface dataset:
Television and Voter Turnout

I use variation across markets in the timing of television’s introduction to identify its impact on voter turnout. The estimated effect is significantly negative, accounting for between a quarter and a half of the total decline in turnout since the 1950s. I argue that substitution away from other media with more political coverage provides a plausible mechanism linking television to voting. As evidence for this, I show that the entry of television in a market coincided with sharp drops in consumption of newspapers and radio, and in political knowledge as measured by election surveys. I also show that both the information and turnout effects were largest in off-year congressional elections, which receive extensive coverage in newspapers but little or no coverage on television.
Andreev interferometry as a probe of superconducting phase correlations in the pseudogap regime of the cuprates

Andreev interferometry—the sensitivity of the tunneling current to spatial variations in the local superconducting order at an interface—is proposed as a probe of the spatial structure of the phase correlations in the pseudogap state of the cuprate superconductors. To demonstrate this idea theoretically, a simple tunneling model is considered, via which the tunneling current is related to the equilibrium phase-phase correlator in the pseudogap state. These considerations suggest that measurement of the low-voltage conductance through mesoscopic contacts of varying areas provides a scheme for accessing phase-phase correlation information. For illustrative purposes, quantitative predictions are made for a model of the pseudogap state in which the phase ~but not the amplitude! of the superconducting order varies randomly, and does so with correlations consistent with certain proposed pictures of the pseudogap state.
The Real Product Market Impact of Mergers

I document sources of value creation in mergers by analyzing novel data on the quality and price of goods sold by merging firms. When two competitors in a product market merge, their products converge in quality, and prices fall relative to the competition. These effects take two to three years to be fully realized and are stronger in mature industries. Prices do not fall, however, when the acquirer is diversifying into a new product market. This direct evidence of real changes induced by merger activity is consistent with consolidation by related merging firms to achieve operational efficiencies and lower costs.
Transverse Beam Shape Measurements of Intense Proton Beams Using Optical Transition Radiation

A number of particle physics experiments are being proposed as part of the Department of Energy HEP Intensity Frontier. Many of these experiments will utilize megawatt level proton beams onto targets to form secondary beams of muons, kaons and neutrinos. These experiments require transverse size measurements of the incident proton beam onto target for each beam spill. Because of the high power levels, most beam intercepting profiling techniques will not work at full beam intensity. The possibility of utilizing optical transition radiation (OTR) for high intensity proton beam profiling is discussed. In addition, previous measurements of OTR beam profiles from the NuMI beamline are presented.
Chelation-controlled reduction: Stereoselective formation of syn-1,3-diols and synthesis of compactin and mevinolin lactone

Chelation-controlled reduction of chiral beta-alkoxy ketones containing a competing beta'-oxygen functionality has been investigated. Various syn-1,3-diols were prepared conveniently by reduction of beta-alkoxy ketones with LiI/LiAlH(4) (syn:anti selectivity up to >99:1). The corresponding beta-alkoxy ketones were derived from nitro-aldol reactions of chiral alkoxy aldehydes with a series of nitro compounds. This methodology is utilized in a short and efficient synthesis of the delta-lactone moiety of the HMG-CoA reductase inhibitors compactin and mevinolin.
Learning Dynamic Feature Selection for Fast Sequential Prediction

We present paired learning and inference algorithms for significantly reducing computation and increasing speed of the vector dot products in the classifiers that are at the heart of many NLP components. This is accomplished by partitioning the features into a sequence of templates which are ordered such that high confidence can often be reached using only a small fraction of all features. Parameter estimation is arranged to maximize accuracy and early confidence in this sequence. Our approach is simpler and better suited to NLP than other related cascade methods. We present experiments in left-to-right part-of-speech tagging, named entity recognition, and transition-based dependency parsing. On the typical benchmarking datasets we can preserve POS tagging accuracy above 97% and parsing LAS above 88.5% both with over a five-fold reduction in run-time, and NER F1 above 88 with more than 2x increase in speed.
Spectra of Edge-Independent Random Graphs

Let $G$ be a random graph on the vertex set $\{1,2,\ldots, n\}$ such that edges in $G$ are determined by independent random indicator variables, while the probabilities $p_{ij}$ for $\{i,j\}$ being an edge in $G$ are not assumed to be equal. Spectra of the adjacency matrix and the normalized Laplacian matrix of $G$ are recently studied by Oliveira and Chung-Radcliffe. Let $A$ be the adjacency matrix of $G$, $\bar A={\rm E}(A)$, and $\Delta$ be the maximum expected degree of $G$. Oliveira first proved that asymptotically almost surely $\|A-\bar A\|=O(\sqrt{\Delta \ln n})$ provided $\Delta\geq C \ln n$ for some constant $C$. Chung-Radcliffe improved the hidden constant in the error term using a new Chernoff-type inequality for random matrices. Here we prove that asymptotically almost surely $\|A-\bar A\|\leq (2+o(1))\sqrt{\Delta}$ with a slightly stronger condition $\Delta\gg \ln^4 n$. For the Laplacian matrix $L$ of $G$, Oliveira and Chung-Radcliffe proved similar results $\|L-\bar L\|=O(\sqrt{\ln n}/\sqrt{\delta})$ provided the minimum expected degree $\delta\geq C' \ln n$ for some constant $C'$; we also improve their results by removing the $\sqrt{\ln n}$ multiplicative factor from the error term under some mild conditions. Our results naturally apply to the classical Erdős–Renyi random graphs, random graphs with given expected degree sequences, and bond percolation of general graphs.
Design and Performance of the Solar Maximum Mission Hard X-Ray Burst Spectrometer

The Hard X-ray Burst Spectrometer acquires data on the temporal and energy distribution of solar X-rays in the energy region from 25 to 385 keV. The detector system is a CsI(Na) central detector, and an anti-coincidence shield with photomultiplier tubes optically coupled to the central and shield crystals. Additional detectors are included for calibration and South Atlantic Anomaly monitoring. A 15 channel pulse height analysis is performed over the energy range every 128 milliseconds. This instrument is capable of handling event rates up to 500 kHz and provides high rate data up to 100 kHz with low spectral distortion. Nine accumulated rates are telemetered every 8.192 seconds. A unique feature of the instrument is the ability to sample rates from the central detector or shield with a one millisecond minimum time resolution. Such samples are stored in a 32768 sample memory with a 40 percent pretrigger event history and a 60 percent posttrigger history.
Photodissociation and the Morphology of Hi in Galaxies

Young massive stars produce Far-UV photons which dissociate the molecular gas on the surfaces of their parent molecular clouds. Of the many dissociation products which result from this “back-reaction”, atomic hydrogen H I is one of the easiest to observe through its radio 21-cm hyperfine line emission. In this paper I first review the physics of this process and describe a simplified model which has been developed to permit an approximate computation of the column density of photodissociated H i which appears on the surfaces of molecular clouds. I then review several features of the H i morphology of galaxies on a variety of length scales and describe how photodissociation might account for some of these observations. Finally, I discuss several consequences which follow if this view of the origin of HI in galaxies continues to be successful.
Feature based hex meshing methodology: feature recognition and volume decomposition ☆

Considerable progress has been made on automatic hexahedral mesh generation in recent years. A few automated meshing algorithms (e.g. mapping, submapping, sweeping) have proven to be very reliable on certain classes of geometry. While it is always worth pursuing general algorithms viable on arbitrary geometry, a combination of the well-established algorithms is ready to take on classes of complicated geometry. By partitioning the entire geometry into meshable pieces matched with appropriate meshing algorithms, the original geometry becomes meshable and may achieve better mesh quality. Each meshable portion is recognized as a meshing feature. This paper, which is a part of the feature based meshing methodology, presents the work on shape recognition and volume decomposition to automatically decompose a CAD model into hex meshable volumes. There are four phases in this approach: Feature Determination to extract decomposition features; Cutting Surfaces Generation to form the cutting surfaces; Body Decomposition to get the imprinted volumes; and Meshing Algorithm Assignment to match volumes decomposed with appropriate meshing algorithms. This paper focuses on describing feature determination and volume decomposition; the last part has been described in another paper. The feature determination procedure is based on the CLoop feature recognition algorithm that is extended to be more general. Some decomposition and meshing results are demonstrated in the final section.
Ka-band MMIC beam steered transmitter array

A 32 GHz six-element linear transmitter array utilizing monolithic microwave integrated circuit (MMIC) phase shifters and power amplifiers was developed, fabricated, and tested. The array is composed of an RF signal distribution subsystem, a set of two MMIC carriers, and a patch antenna subsystem. The mean and standard deviation of the phase shift was 7.0+or-1.6% over the range 0 degrees to 300 degrees . The mean and standard deviation of output power at 1 dB gain compression was 13.6+or-0.3 dBm. Several externally tuned devices are capable of producing as much as 21.5 dBm with a power-added efficiency of 14.5% at 1-dB gain compression. The array provides a beamwidth of 7.5 degrees and has demonstrated acceptable beam steering over +or-8 degrees . >
An adaptive radiation model for the origin of new gene functions.

The evolution of new gene functions is one of the keys to evolutionary innovation. Most novel functions result from gene duplication followed by divergence. However, the models hitherto proposed to account for this process are not fully satisfactory. The classic model of neofunctionalization holds that the two paralogous gene copies resulting from a duplication are functionally redundant, such that one of them can evolve under no functional constraints and occasionally acquire a new function. This model lacks a convincing mechanism for the new gene copies to increase in frequency in the population and survive the mutational load expected to accumulate under neutrality, before the acquisition of the rare beneficial mutations that would confer new functionality. The subfunctionalization model has been proposed as an alternative way to generate genes with altered functions. This model also assumes that new paralogous gene copies are functionally redundant and therefore neutral, but it predicts that relaxed selection will affect both gene copies such that some of the capabilities of the parent gene will disappear in one of the copies and be retained in the other. Thus, the functions originally present in a single gene will be partitioned between the two descendant copies. However, although this model can explain increases in gene number, it does not really address the main evolutionary question, which is the development of new biochemical capabilities. Recently, a new concept has been introduced into the gene evolution literature which is most likely to help solve this dilemma. The key point is to allow for a period of natural selection for the duplication per se, before new function evolves, rather than considering gene duplication to be neutral as in the previous models. Here, I suggest a new model that draws on the advantage of postulating selection for gene duplication, and proposes that bursts of adaptive gene amplification in response to specific selection pressures provide the raw material for the evolution of new function.
Effects of SFAS 133 on the Risk Relevance of Accounting Measures of Banks’ Derivative Exposures

ABSTRACT: We provide evidence on the effects of SFAS 133 on the risk relevance of accounting measures of bank derivative exposures to bond markets. First, we find that interest rate derivatives classified as hedging are more negatively associated with fixed-rate bond spreads after SFAS 133. We also find that hedging derivatives offset non-trading positions to a greater extent after SFAS 133. Second, for the largest 25 banks, we find that interest and foreign exchange rate trading derivatives are more negatively associated with fixed-rate bond spreads after SFAS 133, consistent with more economic hedges being classified as trading after SFAS 133. For these banks, trading derivative exposures offset non-derivative trading exposures to a greater extent after SFAS 133. Our results suggest that, contrary to critics’ claims, SFAS 133 has increased the risk relevance of accounting measures of derivative exposures to bond investors and benefited banks in terms of reducing their cost of capital.
A new approach to modeling and analyzing security of networked systems

Modeling and analyzing security of networked systems is an important problem in the emerging Science of Security and has been under active investigation. In this paper, we propose a new approach towards tackling the problem. Our approach is inspired by the shock model and random environment techniques in the Theory of Reliability, while accommodating security ingredients. To the best of our knowledge, our model is the first that can accommodate a certain degree of adaptiveness of attacks, which substantially weakens the often-made independence and exponential attack inter-arrival time assumptions. The approach leads to a stochastic process model with two security metrics, and we attain some analytic results in terms of the security metrics.
Rhodium-catalyzed reductive mannich coupling of vinyl ketones to N-sulfonylimines mediated by hydrogen.

Catalytic hydrogenation of methyl vinyl ketone (MVK) and ethyl vinyl ketone (EVK) in the presence of N-(o-nitrophenylsulfonyl)imines 8a−13a at ambient pressure with tri-2-furylphosphine-ligated rhodium catalysts enables formation of Mannich products 8b−13b and 8c−13c with moderate to good levels of syn-diastereoselectivity. As revealed by an assay of various N-protecting groups, excellent yields of reductive Mannich product also are obtained for N-arylimines 1a−4a, although diminished levels of syn-diastereoselectivity are observed. Coupling of MVK to imine 8a under a deuterium atmosphere provides deuterio-8b, which incorporates a single deuterium atom at the former enone β-position.
The antiguiding parameter in mid-infrared optically pumped semiconductor lasers

We describe measurements of the antiguiding parameter, α, for several optically pumped semiconductor lasers. The two W lasers, incorporated 14 type-II quantum wells (QWs) and operated at wavelengths of ∼ 3.5 and ∼ 4.5 μm. The lasers displayed low antiguiding factors of ∼ 1.0. We attribute the low α's for the W lasers to the higher QW gain as well as to inhomogeneous broadening induced by the 14 QWs. The differing well widths and the independent optical pumping of the wells, leads to a net gain spectrum that is symmetrical about the gain peak. This symmetry, in turn, leads to small differential index shifts at the gain peak; the result of the small differential index and large differential gain is low antiguiding.
The interactions of cyclophosphazenes with olefin containing exocyclic groups

Density functional calculations on the series N 3 P 3 F 5 R(R=CH 2 CH 3 , CH=CH 2 , C L CH) show that the phosphazene substituent effect is similar to that of CF 3 and is dominated by  bond polarity. UV-photoelectron measurements also favor a  bond polarization effect. Calculations on N 3 P 3 F 5 ECH=CH 2 (E=O, CH 2 ) and photoelectron spectroscopy of the vinyloxy derivative show the strong electronic effect of the phosphazene, which is dominated by the  bond polarization mechanism. Extensive NMR correlations for substituted vinyloxy phosphazenes indicate the sensitivity of these effects to the nature of the ring substituents. The reactivity ratio and NMR data for styryloxy phosphazenes demonstrate the absence of significant mesomeric interactions.
System, scholar or students? Which most influences online MBA course effectiveness?

Considering the increasingly challenging resource environments in many business schools, this study examined whether course technologies, learner behaviors or instructor behaviors best predict online course outcomes so that administrators and support personnel can prioritize their efforts and investments. Based on reviewing prior online and blended management education literature, we hypothesized that instructor behaviors would be most predictive of online course outcomes. However, our study of 48 online Master of Business Administration courses found that although instructor behaviors (operationalized as teaching presence) was the strongest predictor of any of our three outcome variables (perceived learning), only student behaviors (operationalized as social presence) significantly predicted all three (course grades, perceived learning and delivery medium satisfaction). Technological characteristics, operationalized using variables from the technology acceptance model and media variety, predicted perceived learning (perceived ease of use) and delivery medium satisfaction (perceived usefulness). The paper provides recommendations for instructors and administrators based on the findings, specifically advocating for a balance between instructor and administrator involvement in course design, presentation and conduct. The paper concludes by describing research opportunities regarding the roles of social presence in and collaborative approaches to online learning in business schools.
The assembly of β-methylene-TAD, a metabolically stable analogue of the antitumor agent tad, by the stepwise esterification of monodeprotected methylenebis-(phosphonate) benzyl esters under mitsunobu conditions

Abstract Synthesis of the metabolically stable analogue of thiazole-4-carboxamide ademine dinucleotide (β-methylene-TAD) was achieved via the sequential monodeprotection of tetrabenzyl methylenebis(phosphonate) after two rounds of Mitsunobu esterifications with the corresponding nucleoside components, tiazofurin and adenosine.
Evaluating density forecasts via the copula approach

Abstract In this paper, we develop a general approach for constructing simple tests for the correct density forecasts, or equivalently, for i.i.d. uniformity of appropriately transformed random variables. It is based on nesting a series of i.i.d. uniform random variables into a class of copula-based stationary Markov processes. As such, it can be used to test for i.i.d. uniformity against alternative processes that exhibit a wide variety of marginal properties and temporal dependence properties, including skewed and fat-tailed marginal distributions, asymmetric dependence, and positive tail dependence. In addition, we develop tests for the dependence structure of the forecasting model that are robust to possible misspecification of the marginal distribution.
Molecular phylogenetic biodiversity assessment of arctic and boreal ectomycorrhizal Lactarius Pers. (Russulales; Basidiomycota) in Alaska, based on soil and sporocarp DNA.

Despite the critical roles fungi play in the functioning of ecosystems, especially as symbionts of plants and recyclers of organic matter, their biodiversity is poorly known in high-latitude regions. In this paper, we discuss the molecular diversity of one of the most diverse and abundant groups of ectomycorrhizal fungi: the genus Lactarius Pers. We analysed internal transcribed spacer rDNA sequences from both curated sporocarp collections and soil polymerase chain reaction clone libraries sampled in the arctic tundra and boreal forests of Alaska. Our genetic diversity assessment, based on various phylogenetic methods and operational taxonomic unit (OTU) delimitations, suggests that the genus Lactarius is diverse in Alaska, with at least 43 putative phylogroups, and 24 and 38 distinct OTUs based on 95% and 97% internal transcribed spacer sequence similarity, respectively. Some OTUs were identified to known species, while others were novel, previously unsequenced groups. Nonasymptotic species accumulation curves, the disparity between observed and estimated richness, and the high number of singleton OTUs indicated that many Lactarius species remain to be found and identified in Alaska. Many Lactarius taxa show strong habitat preference to one of the three major vegetation types in the sampled regions (arctic tundra, black spruce forests, and mixed birch-aspen-white spruce forests), as supported by statistical tests of UniFrac distances and principal coordinates analyses (PCoA). Together, our data robustly demonstrate great diversity and nonrandom ecological partitioning in an important boreal ectomycorrhizal genus within a relatively small geographical region. The observed diversity of Lactarius was much higher in either type of boreal forest than in the arctic tundra, supporting the widely recognized pattern of decreasing species richness with increasing latitude.
Combinatorial QSAR modeling of P-glycoprotein substrates.

Quantitative structure−activity (property) relationship (QSAR/QSPR) models are typically generated with a single modeling technique using one type of molecular descriptors. Recently, we have begun to explore a combinatorial QSAR approach which employs various combinations of optimization methods and descriptor types and includes rigorous and consistent model validation (Kovatcheva, A.; Golbraikh, A.; Oloff, S.; Xiao, Y.; Zheng, W.; Wolschann, P.; Buchbauer, G.; Tropsha, A. Combinatorial QSAR of Ambergris Fragrance Compounds. J. Chem. Inf. Comput. Sci. 2004, 44, 582−95). Herein, we have applied this approach to a data set of 195 diverse substrates and nonsubstrates of P-glycoprotein (P-gp) that plays a crucial role in drug resistance. Modeling methods included k-nearest neighbors classification, decision tree, binary QSAR, and support vector machines (SVM). Descriptor sets included molecular connectivity indices, atom pair (AP) descriptors, VolSurf descriptors, and molecular operation environment descripto...
A practical excimer laser-based cleaning tool for removal of surface contaminants

A laser-cleaning tool capable of removing surface contaminants such as submicron-sized particulates and organic films has been constructed and implemented in practical use. An industrial-grade KrF excimer laser is utilized to irradiate the solid surface to be cleaned. The nanosecond-pulsed laser irradiation, shortly after the deposition of a thin liquid film on the surface, induces explosive vaporization of the liquid and removal of particulates ("steam cleaning"). The ultraviolet (UV) irradiation also causes ablative photodecomposition of organic film contaminants on the surface ("dry cleaning"). Hence, cleaning can best be done with the combination of these two laser-cleaning modes. The excimer laser cleaning tool is constructed with an aim toward practical use: It includes a computer-controlled laser beam scanning system and a stable liquid film deposition unit, providing a cleaning rate of over 200 cm /min. Semiconductor, metal, and ceramic sample surfaces, contaminated with 1-/spl mu/m sized alumina particles and micron-thick epoxy films, are tested by laser cleaning. The effectiveness of laser cleaning is compared with ultrasonic technique. The cleaning strategy and the probability of thermal damage due to laser cleaning are discussed. >
Improved exact algorithms for MAX-SAT

Abstract In this paper, we present improved exact and parameterized algorithms for the maximum satisfiability problem. In particular, we give an algorithm that computes a truth assignment for a boolean formula F satisfying the maximum number of clauses in time O(1.3247 m | F |), where m is the number of clauses in F , and | F | is the sum of the number of literals appearing in each clause in F . Moreover, given a parameter k , we give an O(1.3695 k +| F |) parameterized algorithm that decides whether a truth assignment for F satisfying at least k clauses exists. Both algorithms improve the previous best algorithms by Bansal and Raman for the problem.
Efficient Reduction of Esters to Aldehydes through Iridium‐Catalyzed Hydrosilylation

A simple, mild, and highly efficient method for the title reaction is reported by using a commercially available catalyst.
The use of crystal structures to elucidate solution coordination chemistry

Abstract The structures of discrete metal complexes in the solid state provide insights with respect to the nature of the coordinate bonding and the conformations of the ligands in solution, provided that no coordinate bonds are broken or drastically rearranged in the solution solid transformation. From the thirty joint publications containing crystal structure determinations, most of which involved collaboration with Dr Clearfield's research group, ten examples of crystal structure determinations are selected to show the nature of these insights. These examples include three cobalt complexes, three copper(II) complexes, one copper(I) complex, a gadolinium(III) complex and two iron(III) complexes. In all cases, the crystal structures were important in demonstrating the probable arrangement of ligand donor atoms around the metal centers in the complexes formed in solution.
Efficient Authenticated Data Structures for Graph Connectivity and Geometric Search Problems

Following in the spirit of data structure and algorithm correctness checking, authenticated data structures provide cryptographic proofs that their answers are as accurate as the author intended, even if the data structure is being controlled by a remote untrusted host. In this paper we present efficient techniques for authenticating data structures that represent graphs and collections of geometric objects. We use a data-querying model where a data structure maintained by a trusted source is mirrored at distributed untrusted servers, called responders, with the responders answering queries made by users: when a user queries a responder, along with the answer to the issued query, he receives a cryptographic proof that allows the verification of the answer trusting only a short statement (digest) signed by the source. We introduce the path hash accumulator, a new primitive based on cryptographic hashing for efficiently authenticating various properties of structured data represented as paths, including any decomposable query over sequences of elements. We show how to employ our primitive to authenticate queries about properties of paths in graphs and search queries on multi-catalogs. This allows the design of new, efficient authenticated data structures for fundamental problems on networks, such as path and connectivity queries over graphs, and complex queries on two-dimensional geometric objects, such as intersection and containment queries. By building on our new primitive we achieve efficiency and modularity: our schemes can be easily analyzed in terms of complexity and security and are simple to implement. Our work has applications to the authentication of network management systems and geographic information systems.
Does Futures Speculation Destabilize Commodity Markets

This paper examines how increased speculator participation in the commodity futures market affects market outcomes, including trades' price impacts, price volatility, and market quality. Contrary to the popular belief that speculators are responsible for the recent commodity price fluctuation, my analysis finds no evidence that speculators destabilize the commodity spot market. Instead, speculators contribute to lower price volatility, enhanced price efficiency, and better liquidity in the commodity markets. More importantly, I show that speculators either have no effect or stabilize prices during periods of large price movement. My findings suggest speculators have had a significant and in fact positive influence on the commodity market during the recent “financialization” period, implying that restricting speculative trading in the futures market is not an efficient way to stabilize the commodity market. © 2015 Wiley Periodicals, Inc. Jrl Fut Mark 35:696–714, 2015
The inner edge of the plasma sheet and the diffuse aurora

Three dimensional measurements from the ISEE-1 low energy electron spectrometer are used to map the location of the inner edge of the plasma sheet and study the anisotropies in the electron distribution function associated with this boundary. Lower energy plasma sheet electrons have inner edges closer to the Earth than higher energies with the separations at different energies being larger near dawn and after dusk than at midnight. Lowest energy inner edges are frequently located adjacent to the plasmapause in the dawn hemisphere but are often separated from it in the dusk hemisphere by a gap of at least several Re. The energy dispersion is minimal in the afternoon quadrant where the inner edge is near the magnetopause and frequently oscillating on a time scale of minutes. The location of the inner edge is probably determined primarily by the motion of electrons in the existing electric and magnetic fields rather than by strong diffusion as has sometimes been supposed.
Homophily and Contagion Are Generically Confounded in Observational Social Network Studies.

The authors consider processes on social networks that can potentially involve three factors: homophily, or the formation of social ties due to matching individual traits; social contagion, also known as social influence; and the causal effect of an individual’s covariates on his or her behavior or other measurable responses. The authors show that generically, all of these are confounded with each other. Distinguishing them from one another requires strong assumptions on the parametrization of the social process or on the adequacy of the covariates used (or both). In particular the authors demonstrate, with simple examples, that asymmetries in regression coefficients cannot identify causal effects and that very simple models of imitation (a form of social contagion) can produce substantial correlations between an individual’s enduring traits and his or her choices, even when there is no intrinsic affinity between them. The authors also suggest some possible constructive responses to these results.
Operational factors affecting microgravity levels in orbit

Microgravity levels desired for proposed materials processing payloads are fundamental considerations in the design of future space platforms. Disturbance sources, such as aerodynamic drag, attitude control torques, crew motion, and orbital dynamics, influence the microgravity levels attainable in orbit. The nature of these effects is assessed relative to platform design parameters such as orbital altitude and configuration geometry, and examples are presented for a representative spacecraft configuration. The possible applications of control techniques to provide extremely low acceleration levels are also discussed.
Biochemical and biosynthetic preparation of natural product-like cyclic peptide libraries

Cyclic peptides are at the forefront of efforts to pursue previously ‘undruggable’ therapeutic targets. Increasingly, researchers are adapting natural products and their biosynthetic systems to the preparation of cyclic peptide libraries. Alternatively, extant biotechnologies are being modified to increase the range and diversity of the compounds that they can access and incorporate into natural product motifs. A number of such systems have been validated with lead discovery and optimization against therapeutically relevant targets.
Compensation of robot joint variables using special Jacobian matrices

In dealing with an industrial manipulator, the end-effector accuracy is a major concern. The positioning of the end effector is determined by the controller that utilizes the data from a closed-form kinematic inversion. The closed-form inversion uses nominal, i.e., manufacturer specified, values of link lengths, twists, and offsets. Due to manufacturing tolerances, set-up, and usage, these nominal parameters may be inaccurate. If the nominal parameters contain built-in error values, the closed-form kinematic inversion will yield incorrect joint values, and the actual end-effector position will deviate from its desired position. One may use a parameter identification method to identify the position-independent error parameter values. This article assumes that this has been done and it presents an iterative compensation algorithm (ICA) through which the identified position-independent parameter error values may be used to correct the joint values obtained through the closed-form kinematic inversion. The Denavit and Hartenberg (D-H) parameters (θsαa) are used to model the given M-jointed manipulator, and a set of four special Jacobian matrices (Jθ, Js, Jα, and Ja) are formulated. The iterative compensation algorithm allows one to determine the M unknown position-dependent joint error values by using these four special Jacobian matrices. The improvements obtained through the use of the compensation algorithm will be presented for regular trajectories, as well as when the robot nears certain singularity conditions. Since it is important to know a priori a definite number of iterations that must be performed, the level of compensation after a fixed number of iterations is also studied. Through the presentation of numerous examples, it is shown that the proposed compensation algorithm is simple and straightforward to implement, and it increases the end-effector accuracy.
Good recognition is non-metric

Abstract Recognition is the fundamental task of visual cognition, yet how to formalize the general recognition problem for computer vision remains an open issue. The problem is sometimes reduced to the simplest case of recognizing matching pairs, often structured to allow for metric constraints. However, visual recognition is broader than just pair-matching: what we learn and how we learn it has important implications for effective algorithms. In this review paper, we reconsider the assumption of recognition as a pair-matching test, and introduce a new formal definition that captures the broader context of the problem. Through a meta-analysis and an experimental assessment of the top algorithms on popular data sets, we gain a sense of how often metric properties are violated by recognition algorithms. By studying these violations, useful insights come to light: we make the case for local distances and systems that leverage outside information to solve the general recognition problem.
Do high energy astrophysical neutrinos trace star formation

The IceCube Neutrino Observatory has provided the first map of the high energy (~ 0.01–1 PeV) sky in neutrinos. Since neutrinos propagate undeflected, their arrival direction is an important identifier for sources of high energy particle acceleration. Reconstructed arrival directions are consistent with an extragalactic origin, with possibly a galactic component, of the neutrino flux. We present a statistical analysis of positional coincidences of the IceCube neutrinos with known astrophysical objects from several catalogs. When considering starburst galaxies with the highest flux in gamma-rays and infrared radiation, up to n=8 coincidences are found, representing an excess over the ~4 predicted for the randomized, or ``null'' distribution. The probability that this excess is realized in the null case, the p-value, is p=0.042. This value falls to p=0.003 for a partial subset of gamma-ray-detected starburst galaxies and superbubble regions in the galactic neighborhood. Therefore, it is possible that starburst galaxies, and the typically hundreds of superbubble regions within them, might account for a portion of IceCube neutrinos. The physical plausibility of such correlation is discussed briefly.
Feedback heating by cosmic rays in clusters of galaxies

Recent observations show that the cooling flows in the central regions of galaxy clusters are highly suppressed. Observed active galactic nuclei (AGN)-induced cavities/bubbles are a leading candidate for suppressing cooling, usually via some form of mechanical heating. At the same time, observed X-ray cavities and synchrotron emission point towards a significant nonthermal particle population. Previous studies have focused on the dynamical effects of cosmic ray pressure support, but none has built successful models in which cosmic ray heating is significant. Here, we investigate a new model of AGN heating, in which the intracluster medium is efficiently heated by cosmic rays, which are injected into the intra-cluster medium (ICM) through diffusion or the shredding of the bubbles by Rayleigh‐Taylor or Kelvin‐Helmholtz instabilities. We include thermal conduction as well. Using numerical simulations, we show that the cooling catastrophe is efficiently suppressed. The cluster quickly relaxes to a quasiequilibrium state with a highly reduced accretion rate and temperature and density profiles which match observations. Unlike the conduction-only case, no fine-tuning of the Spitzer conduction suppression factor f is needed. The cosmic ray pressure, Pc/Pg � 0.1 and ∇Pc � 0.1ρg, is well within observational bounds. Cosmic ray heating is a very attractive alternative to mechanical heating, and may become particularly compelling if Gamma-ray Large Array Space Telescope (GLAST) detects the γ -ray signature of cosmic rays in clusters.
An experimental investigation of screech noise generation

The screech noise generation process from supersonic underexpanded jets, issuing from a sonic nozzle at pressure ratios of 2.4 and 3.3 (fully expanded Mach number, Mj = 1.19 and 1.42), was investigated experimentally. The extremely detailed data provide a fresh, new look at the screech generation mechanism. Spark schlieren visualization at different phases of the screech cycle clearly shows the convection of the organized turbulent structures over a train of shock waves. The potential pressure field (hydrodynamic fluctuations) associated with the organized structures is fairly intense and extends outside the shear layer. The time evolution of the near-field pressure fluctuations was obtained from phase-averaged microphone measurements. Phase-matched combined views of schlieren photographs and pressure fluctuations show the sound generation process. The individual compression and rarefaction parts of the sound waves are found to be generated from similar hydrodynamic fluctuations. A partial interference between the upstream-propagating sound waves and the downstream-propagating hydrodynamic waves is found to be present along the jet boundary. The partial interference manifests itself as a standing wave in the root-mean-square pressure fluctuation data. The standing wavelength is found to be close to, but somewhat different from, the shock spacing. An outcome of the interference is a curious 'pause and go' motion of the sound waves along the jet periphery. Interestingly, a length scale identical to the standing wavelength is found to be present inside the jet shear layer. The coherent fluctuations and the convective velocity of the organized vortices are found to be modulated periodically, and the periodicity is found to match with the standing wavelength distance rather than the shock spacing. The reason for the appearance of this additional length scale, different from the shock spacing, could not be explained. Nevertheless, it is demonstrated that an exact screech frequency formula can be derived from the simple standing wave relationship. The exact relationship shows that the correct spacing between the sources, for a point source model similar to that of Powell (1953), should be a standing wavelength (not the shock spacing).
ARTIST (Asian regional tobacco industry scientist team): Philip Morris' attempt to exert a scientific and regulatory agenda on Asia.

Objective: To describe how the transnational tobacco industry has collaborated with local Asian tobacco monopolies and companies to promote a scientific and regulatory agenda. Methods: Analysis of previously secret tobacco industry documents. Results: Transnational tobacco companies began aggressively entering the Asia market in the 1980s, and the current tobacco industry in Asia is a mix of transnational and local monopolies or private companies. Tobacco industry documents demonstrate that, in 1996, Philip Morris led an organisation of scientific representatives from different tobacco companies called the Asian Regional Tobacco Industry Science Team (ARTIST), whose membership grew to include monopolies from Korea, China, Thailand, and Taiwan and a company from Indonesia. ARTIST was initially a vehicle for PM’s strategies against anticipated calls for global smoke-free areas from a World Health Organization secondhand smoke study. ARTIST evolved through 2001 into a forum to present scientific and regulatory issues faced primarily by Philip Morris and other transnational tobacco companies. Philip Morris’ goal for the organisation became to reach the external scientific and public health community and regulators in Asia. Conclusion: The Asian tobacco industry has changed from an environment of invasion by transnational tobacco companies to an environment of participation with Philip Morris’ initiated activities. With this participation, tobacco control efforts in Asia face new challenges as Philip Morris promotes and integrates its scientific and regulatory agenda into the local Asian tobacco industry. As the local Asian tobacco monopolies and companies can have direct links with their governments, future implementation of effective tobacco control may be at odds with national priorities.
Thymidine Phosphorylase Deficiency Causes MNGIE: An Autosomal Recessive Mitochondrial Disorder

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is an autosomal recessive disorder caused by mutations in the gene encoding thymidine phosphorylase (TP). The disease is characterized clinically by impaired eye movements, gastrointestinal dysmotility, cachexia, peripheral neuropathy, myopathy, and leukoencephalopathy. Molecular genetic studies of MNGIE patients' tissues have revealed multiple deletions, depletion, and site-specific point mutations of mitochondrial DNA. TP is a cytosolic enzyme required for nucleoside homeostasis. In MNGIE, TP activity is severely reduced and consequently levels of thymidine and deoxyuridine in plasma are dramatically elevated. We have hypothesized that the increased levels of intracellular thymidine and deoxyuridine cause imbalances of mitochondrial nucleotide pools that, in turn, lead to the mtDNA abnormalities. MNGIE was the first molecularly characterized genetic disorder caused by abnormal mitochondrial nucleoside/nucleotide metabolism. Future studies are likely to reveal further insight into this expanding group of diseases.
Copper-catalyzed aerobic dehydrogenative cyclization of N-methyl-N-phenylhydrazones: synthesis of cinnolines.

N-Phenylhydrazones as novel substrates for copper-catalyzed aerobic intramolecular dehydrogenative cyclization are presented.
On the size-Ramsey number of hypergraphs

The size-Ramsey number of a graph G is the minimum number of edges in a graph H such that every 2-edge-coloring of H yields a monochromatic copy of G. Size-Ramsey numbers of graphs have been studied for almost 40 years with particular focus on the case of trees and bounded degree graphs. We initiate the study of size-Ramsey numbers for k-uniform hypergraphs. Analogous to the graph case, we consider the size-Ramsey number of cliques, paths, trees, and bounded degree hypergraphs. Our results suggest that size-Ramsey numbers for hypergraphs are extremely dicult to determine, and many open problems remain.
Chemical and Physical Properties of Soot as a Function of Fuel Molecular Structure in a Swirl-Stabilized Combustor

Author(s): Himes, RM; Hack, RL; Samuelsen, GS | Abstract: Soot samples were extracted from a swirl-stabilized, liquid-fuel fired laboratorycombustor to (i) assess the validity of the ASTM smoke point test in predicting thesooting characteristics of fuels in complex combustion systems and (ii) assess theeffect of fuel molecular structure and smoke suppressant additives on the physicaland chemical properties of soot. Fuels utilized were shale JP-8, iso-octane, andblends of iso-octane with either decalin, toluene, tetralin, or 1-methylnaphthalenesuch that smoke points similar to JP-8 were achieved. Each fuel was separatelyblended with 0.05 percent (by weight) ferrocene smoke suppressant. The resultsindicate that the ASTM test can be misleading, increased fuel molecular complexityincreases soot content of higher molecular weight polycyclic aromatics, andferrocene additive reduces small particle number density but not necessarily the sootmass loading. © 1984 by ASME.
Ideas for the future of the IS field

Information systems as a field of intellectual inquiry is now approximately 50 years old. It has many achievements and extensive research to its credit and has established a large group of researchers and experts worldwide. The field has changed and changed and changed again over the last half century. The question addressed in this inaugural issue article is: Where does IS go from hereq This article presents the views of six of the “fathers of the field” about its directions in the years ahead. Each coauthor presents two ideas about the future. The topics covered includes continuing support of the work of organizations, emerging technologies, new ways of communicating, expanding the ways IS performs research, expanding its vision both of what IS is and of its impact, its role as a resource, its model of the IS professional and its graduates, and its staying on top of new technologies and new areas of inquiry.
Investor Protection and Corporate Governance

Recent research has documented large differences among countries in ownership concentration in publicly traded firms, in the breadth and depth of capital markets, in dividend policies, and in the access of firms to external finance. A common element to the explanations of these differences is how well investors, both shareholders and creditors, are protected by law from expropriation by the managers and controlling shareholders of firms. We describe the differences in laws and the effectiveness of their enforcement across countries, discuss the possible origins of these differences, summarize their consequences, and assess potential strategies of corporate governance reform. We argue that the legal approach is a more fruitful way to understand corporate governance and its reform than the conventional distinction between bank-centered and market-centered financial systems.
The Impact of the Boll Weevil, 1892–1932

The boll weevil is America's most celebrated agricultural pest. We analyze new county-level panel data to provide sharp estimates of the time path of the insect's effects on the southern economy. We find that in anticipation of the contact, farmers increased production, attempting to squeeze out one last large crop. Upon arrival, the weevil had a large negative and lasting impact on cotton production, acreage, and especially yields. In response, rather than taking land out of agricultural production, farmers shifted to other crops. We also find striking effects on land values and population movements.