cssi/SciSciGPT-SciSciNet huggingface dataset:
Limits on CO2 Climate Forcing from Recent Temperature Data of Earth

The global atmospheric temperature anomalies of Earth reached a maximum in 1998 which has not been exceeded during the subsequent 10 years. The global anomalies are calculated from the average of climate effects occurring in the tropical and the extratropical latitude bands. El Nino/La Nina effects in the tropical band are shown to explain the 1998 maximum while variations in the background of the global anomalies largely come from climate effects in the northern extratropics. These effects do not have the signature associated with CO2 climate forcing. However, the data show a small underlying positive trend that is consistent with CO2 climate forcing with no-feedback.
Static and Dynamic Performance of Externally Pressurized Fluid Film Journal Bearings in the Turbulent Regime

The fluid film lubrication equations for externally pressurized bearings are solved for steady-state performance and spring and damping coefficients using finite differences and a variable grid bearing model. Turbulence is included as local effective viscosities. Entrance inertia effects are included at the recess edges and are seen to be a significant factor for flow estimates. Performance data is developed for a six-pocket bearing of L/D = 0.75. Experimental verification was obtained for load capacity, flow, and dynamic coefficients, using a two-bearing dynamic test rig and water at speeds from 0 to 4000 rpm. Axial flow of Reynolds numbers range from 22,000 to 125,000.
On the stability of certain spin models in 2+1 dimensions

In this paper we prove large-data local stability theorems for several spin-field models in two dimensions, both in the focusing case (spherical target) and the defocusing case (hyperbolic target).
Exact analysis of the propagation of acoustic waves in multilayered anisotropic piezoelectric plates

Exact analysis of the propagation of acoustic waves in multilayered piezoelectric plates is performed using the transfer matrix method. A general technique for analyzing layered piezoelectric resonators under thickness and lateral field excitation is presented and is applied to the study of zinc oxide on silicon thin film resonators. Both one and two-dimensional analysis with general material anisotropy is performed, and a simplified method for incorporating thin conducting electrodes on the plate's free surfaces is presented. The general methodology described is summarized into efficient algorithms to aid in the implementation of the procedures and some computational aspects are discussed. Results are presented for cutoff behavior as well as general dispersion characteristics for two and three layered plates. >
Coastal adaptation: The case of Ocean Beach, San Francisco

This paper examines the way coastal adaptation at the local level works citing one of the more successful cases of adaptation planning in Ocean Beach, San Francisco. Recent erosions that endangered San Francisco's wastewater treatment system helped push coastal adaptation initiatives to produce the Ocean Beach Master Plan. The plan included scenarios and trade-offs to engage multiple stakeholders including the San Francisco (SF) Public Utilities Commission, the California Coastal Commission, the National Park Service, the SF Department of Public Works, and the user groups of the beach. Investigation into the planning process reveals the benefits of increased public awareness and partnerships as well as limitations of implementation and lack of longer-term solutions.
What avionics engineers should know about pilots and automation

There has been great interest lately in automation issues, spurred partly by accidents and incidents attributed to automation factors, and partly by a recognition that automation related problems can be both highly subtle and very dangerous. One of the reasons underlying automation-related problems is the relatively indiscriminate application of automation based on technological availability rather than operator need. This has placed system operators in roles that are poorly suited to human capabilities. A more productive approach to automation and humans would be to recognize the need to maintain appropriate roles for the human operator, the need to match automation functionality to operator tasks, the need for the human interface to make automation functions highly visible to the operator, and the potential for operator over- and under-reliance on the automation.
Finite Euler products and the Riemann hypothesis

We show that if the Riemann Hypothesis is true, then in a region containing most of the right-half of the critical strip, the Riemann zeta-function is well approximated by short truncations of its Euler product. Conversely, if the approximation by products is good in this region, the zeta-function has at most finitely many zeros in it. We then construct a parameterized family of non-analytic functions with this same property. With the possible exception of a finite number of zeros off the critical line, every function in the family satisfies a Riemann Hypothesis. Moreover, when the parameter is not too large, they have about the same number of zeros as the zeta-function, their zeros are all simple, and they "repel". The structure of these functions makes the reason for the simplicity and repulsion of their zeros apparent and suggests a mechanism that might be responsible for the corresponding properties of the zeta-function's zeros. Computer evidence suggests that the zeros of functions in the family are remarkably close to those of the zeta-function (even for small values of the parameter), and we show that they indeed converge to them as the parameter increases. Furthermore, between zeros of the zeta-function, the moduli of functions in the family tend to twice the modulus of the zeta-function. Both assertions assume the Riemann Hypothesis. We end by discussing analogues for other L-functions and show how they give insight into the study of the distribution of zeros of linear combinations of L-functions.
The generalized A* architecture

We consider the problem of computing a lightest derivation of a global structure using a set of weighted rules. A large variety of inference problems in AI can be formulated in this framework. We generalize A* search and heuristics derived from abstractions to a broad class of lightest derivation problems. We also describe a new algorithm that searches for lightest derivations using a hierarchy of abstractions. Our generalization of A* gives a new algorithm for searching AND/OR graphs in a bottom-up fashion. We discuss how the algorithms described here provide a general architecture for addressing the pipeline problem -- the problem of passing information back and forth between various stages of processing in a perceptual system. We consider examples in computer vision and natural language processing. We apply the hierarchical search algorithm to the problem of estimating the boundaries of convex objects in grayscale images and compare it to other search methods. A second set of experiments demonstrate the use of a new compositional model for finding salient curves in images.
Reconciling Two Views of Cryptography (The Computational Soundness of Formal Encryption)

Two distinct, rigorous views of cryptography have developed over the years, in two mostly separate communities. One of the views relies on a simple but effective formal approach; the other, on a detailed computational model that considers issues of complexity and probability. There is an uncomfortable and interesting gap between these two approaches to cryptography. This paper starts to bridge the gap, by providing a computational justification for a formal treatment of encryption.
Influence of lung volume, fluid and capillary recruitment during positional changes and exercise on thoracic impedance in heart failure.

Abstract It is unclear how dynamic changes in pulmonary–capillary blood volume ( Vc ), alveolar lung volume (derived from end-inspiratory lung volume, EILV) and interstitial fluid (ratio of alveolar capillary membrane conductance and pulmonary capillary blood volume, Dm/ Vc ) influence lung impedance ( Z T ). The purpose of this study was to investigate if positional change and exercise result in increased EILV, Vc and/or lung interstitial fluid, and if Z T tracks these variables. Methods 12 heart failure (HF) patients underwent measurements (Z T , EILV, Vc/Dm) at rest in the upright and supine positions, during exercise and into recovery. Inspiratory capacity was obtained to provide consistent measures of EILV while assessing Z T . Results Z T increased with lung volume during slow vital capacity maneuvers ( p Z T ( p Vc increased and EILV and Dm/ Vc decreased ( p Vc and EILV increased and Dm/ Vc decreased ( p Z T did not change significantly ( p > 0.05). Conclusion Impedance appears sensitive to changes in lung volume and body position which appear to generally overwhelm small acute changes in lung fluid when assed dynamically at rest or during exercise.
Supermarket Pricing Strategies

Most supermarket firms choose to position themselves by offering either everyday low prices (EDLP) across several items or offering temporary price reductions (promotions) on a limited range of items. While this choice has been addressed from a theoretical perspective in both the marketing and economic literature, relatively little is known about how these decisions are made in practice, especially within a competitive environment. This paper exploits a unique store level data set consisting of every supermarket operating in the United States in 1998. For each of these stores, we observe the pricing strategy the firm has chosen to follow, as reported by the firm itself. Using a system of simultaneous discrete choice models, we estimate each store's choice of pricing strategy as a static discrete game of incomplete information. In contrast to the predictions of the theoretical literature, we find strong evidence that firms cluster by strategy by choosing actions that agree with those of its rivals. We also...
Multipole moments of bumpy black holes

General relativity predicts the existence of black holes, compact objects whose spacetimes depend only on their mass, spin, and charge in vacuum (the ``no-hair'' theorem). As various observations probe deeper into the strong fields of black hole candidates, it is becoming possible to test this prediction. Previous work suggested that such tests can be performed by measuring whether the multipolar structure of black hole candidates has the form that general relativity demands, and introduced a family of ``bumpy black hole'' spacetimes to be used for making these measurements. These spacetimes have generalized multipoles, where the deviation from the Kerr metric depends on the spacetime's ``bumpiness.'' In this paper, we show how to compute the Geroch-Hansen moments of a bumpy black hole, demonstrating that there is a clean mapping between the deviations used in the bumpy black hole formalism and the Geroch-Hansen moments. We also extend our previous results to define bumpy black holes whose current moments, analogous to magnetic moments of electrodynamics, deviate from the canonical Kerr value.
Freight industry attitudes towards policies to reduce congestion

This paper presents an analysis of the perceptions held by for-hire and private trucking company logistics and operations managers about the impacts of congestion on their operations and the feasibility and effectiveness of actual and potential congestion mitigation policies. Responses to an extensive survey of nearly 1200 California-based or large national carriers are examined using confirmatory factor analysis. The method applied facilitates both the grouping of congestion relief policies into classes and the identification of characteristics of companies which lead them to favor one set of policies over others. This research comes at a time when California government leaders and transportation policy analysts are struggling with key resource allocation issues that will impact the short and long term future of goods movement in the state. To the greatest extent possible, insights of CVO users of the transportation network should be included in the policy analysis process.
A duration analysis of CONALEP (Mexico's National Technical Professional School)

Mexico's National Technical Professional School (Colegio Nacional de Educaci�n Profesional T�cnica, CONALEP) is the largest technical education system in the country. CONALEP serves low-income students at the upper-secondary school level in Mexico. Using graduate tracer surveys from CONALEP, the author analyzes the impact of modular courses and reform programs implemented by CONALEP in 1991-92 on CONALEP graduates' labor market outcomes. Results indicate that graduates from the pre-reform program had to search longer for a job compared with those of the post-reform program. Graduates from the post-reform program have 45 percent higher probability of finding a job than those from the pre-reform program. However, the pre-reform program cohorts earned higher hourly wages than those from the post-reform program.
The lazy sweep ray casting algorithm for rendering irregular grids

Lazy sweep ray casting is a fast algorithm for rendering general irregular grids. It is based on the sweep-plane paradigm, and it is able to accelerate ray casting for rendering irregular grids, including disconnected and nonconvex unstructured irregular grids (even with holes) with a rendering cost that decreases as the "disconnectedness" decreases. The algorithm is carefully tailored to exploit spatial coherence even if the image resolution differs substantially from the object space resolution. Lazy sweep ray casting has several desirable properties, including its generality, (depth-sorting) accuracy, low memory consumption, speed, simplicity of implementation and portability (e.g. no hardware dependencies). We establish the practicality of our method through experimental results based on our implementation, which is shown to be substantially faster (by up to two orders of magnitude) than other algorithms implemented in software. We also provide theoretical results, both lower and upper bounds, on the complexity of ray casting of irregular grids.
Metal-Based Turn-On Fluorescent Probes for Sensing Nitric Oxide

Nitric oxide, a reactive free radical, regulates a variety of biological processes. The absence of tools to detect NO directly, rapidly, specifically, and selectively motivated us to synthesize metal-based fluorescent probes to visualize the presence of NO. We prepared and investigated Co(II), Fe(II), Ru(II), Rh(II), and Cu(II) complexes as turn-on fluorescent NO sensors. Our exploration has provided insight into how the interaction of transition-metal centers with nitric oxide can be utilized for NO sensing.
White Dwarf Sequences in Dense Star Clusters

We use the results of realistic N-body simulations to investigate the appearance of the white dwarf population in dense star clusters. We show that the presence of a substantial binary population in a star cluster, and the interaction of this population with the cluster environment, has serious consequences for the morphology of the observed white dwarf sequence and the derived white dwarf cooling age of the cluster. We find that over time the dynamical evolution of the cluster?mass segregation, stellar interactions, and tidal stripping?hampers the use of white dwarfs as tracers of the initial mass function and also leads to a significant enhancement of the white dwarf mass fraction. Future observations of star clusters should be conducted slightly interior to the half-mass radius of the cluster in order to best obtain information about the cluster age and initial mass function from the white dwarf luminosity function. The evolution of binary stars and the cluster environment must necessarily be accounted for when the white dwarf populations of dynamically evolved star clusters are studied.
A Quantitative Analysis of Induction Motor Performance Improvement by SCR Voltage Control

Minimum input power and maximum efficiency operation occur at characteristic slip values which can be realized for any induction motor operating at part load by properly adjusting the amplitude of the applied stator terminal voltages. These two criteria are shown to yield perceptibly different results when the motor is driven from a silicon-controlled rectifier (SCR) voltage controller. In addition, it is demonstrated that a constant power factor controller results in an operating regime which is substantially poorer than operation at either minimum input power or maximum efficiency. It is further shown that minimum stator current and minimum power factor angle criteria yield results which are closer to the ideal than the constant power factor controller.
Algorithms to Detect Multiprotein Modularity Conserved during Evolution

Detecting essential multiprotein modules that change infrequently during evolution is a challenging algorithmic task that is important for understanding the structure, function, and evolution of the biological cell. In this paper, we define a measure of modularity for interactomes and present a linear-time algorithm, Produles, for detecting multiprotein modularity conserved during evolution that improves on the running time of previous algorithms for related problems and offers desirable theoretical guarantees. We present a biologically motivated graph theoretic set of evaluation measures complementary to previous evaluation measures, demonstrate that Produles exhibits good performance by all measures, and describe certain recurrent anomalies in the performance of previous algorithms that are not detected by previous measures. Consideration of the newly defined measures and algorithm performance on these measures leads to useful insights on the nature of interactomics data and the goals of previous and current algorithms. Through randomization experiments, we demonstrate that conserved modularity is a defining characteristic of interactomes. Computational experiments on current experimentally derived interactomes for Homo sapiens and Drosophila melanogaster, combining results across algorithms, show that nearly 10 percent of current interactome proteins participate in multiprotein modules with good evidence in the protein interaction data of being conserved between human and Drosophila.
STAT4 Deficiency Reduces Obesity-Induced Insulin Resistance and Adipose Tissue Inflammation

Signal transducer and activator of transcription (STAT) 4 is one of the seven members of the STAT family. STAT4 has a prominent role in mediating interleukin-12–induced T-helper cell type 1 lineage differentiation. T cells are key players in the maintenance of adipose tissue (AT) inflammation. The role of STAT4 in obesity and AT inflammation is unknown. We sought to determine the role of STAT4 in AT inflammation in obesity-induced insulin resistance. We studied STAT4-null mice on the C57Bl6/J background. We have found that STAT4−/−C57Bl6/J mice develop high-fat diet–induced obesity (DIO) similar to wild-type controls, but that they have significantly improved insulin sensitivity and better glucose tolerance. Using flow cytometry and real-time PCR, we show that STAT4−/− mice with DIO produce significantly reduced numbers of inflammatory cytokines and chemokines in adipocytes, have reduced numbers of CD8+ cells, and display increased alternative (M2) macrophage polarization. CD8+ cells, but not CD4+ cells, from STAT4−/− mice displayed reduced in vitro migration. Also, we found that adipocyte inflammation is reduced and insulin signaling is improved in STAT4−/− mice with DIO. We have identified STAT4 as a key contributor to insulin resistance and AT inflammation in DIO. Targeting STAT4 activation could be a novel approach to reducing AT inflammation and insulin resistance in obesity.
Discovery of Two Nearby, Peculiar L Dwarfs from the 2MASS Proper Motion Survey: Young or Metal-Rich?

We present the discovery of two nearby L dwarfs from our 2MASS proper-motion search, which uses multiepoch 2MASS observations covering ~4700 deg^2 of sky. 2MASS J18212815+1414010 and 2MASS J21481628+4003593 were overlooked by earlier surveys due to their faint optical magnitudes and their proximity to the Galactic plane (10° ≤ | b | ≤ 15°). Assuming that both dwarfs are single, we derive spectrophotometric distances of ~10 pc, thus increasing the number of known L dwarfs within 10 pc to 10. In the near-infrared, 2MASS J21481628+4003593 shows a triangular H-band spectrum, strong CO absorption, and a markedly red J − K_s color (2.38 ± 0.06) for its L6 optical spectral type. 2MASS J18212815+1414010 also shows a triangular H-band spectrum and a slightly red J − K_s color (1.78 ± 0.05) for its L4.5 optical spectral type. Both objects show strong silicate absorption at 9-11 μm. Cumulatively, these features imply an unusually dusty photosphere for both of these objects. We examine several scenarios to explain the underlying cause for their enhanced dust content and find that a metal-rich atmosphere or a low surface gravity are consistent with these results. 2MASS J18212815+1414010 may be young (and therefore have a low surface gravity) based on its low tangential velocity of 10 km s^−1. On the other hand, 2MASS J21481628+4003593 has a high tangential velocity of 62 km s^−1 and is therefore likely old. Hence, high metallicity and low surface gravity may lead to similar effects.
LITHOSPHERIC FLEXURE BENEATH THE FREYJA MONTES FOREDEEP, VENUS: CONSTRAINTS ON LITHOSPHERIC THERMAL GRADIENT AND HEAT FLOW

Analysis of Venera 15 and 16 radar images and topographic data from the Freyja Montes region on Venus suggests that this mountain belt formed as a result of a sequence of underthrusts of the lithosphere of the North Polar Plains beneath the highlands of Ishtar Terra. The lithospheric flexure hypothesis is tested, and the effective thickness Te of the elastic lithosphere of the underthrusting portion of the North Polar Plains is estimated by fitting individual topographic profiles to deflection curves for a broken elastic plate. The theoretical curves fit the observed topographic profiles to within measurement error for values of flexural rigidity D in the range (0.8-3) x 10 to the 22nd N m, equivalent to Te in the range 11-18 km.
Prions and transmissible spongiform encephalopathy (TSE) chemotherapeutics: A common mechanism for anti-TSE compounds?

No validated treatments exist for transmissible spongiform encephalopathies (TSEs or prion diseases) in humans or livestock. The search for TSE therapeutics is complicated by persistent uncertainties about the nature of mammalian prions and their pathogenic mechanisms. In pursuit of anti-TSE drugs, we and others have focused primarily on blocking conversion of normal prion protein, PrPC, to the TSE-associated isoform, PrPSc. Recently developed high-throughput screens have hastened the identification of new inhibitors with strong in vivo anti-TSE activities such as porphyrins, phthalocyanines, and phosphorthioated oligonucleotides. New routes of administration have enhanced beneficial effects against established brain infections. Several different classes of TSE inhibitors share structural similarities, compete for the same site(s) on PrPC, and induce the clustering and internalization of PrPC from the cell surface. These activities may represent a common mechanism of action for these anti-TSE compounds.
Review of ionic liquids with fluorine-containing anions

Interest in ionic liquids has grown markedly in recent years. The syntheses, characterization and properties of quaternary alkyl-substituted ammonium, imidazolium, triazolium and pyridinium salts with a variety of fluorine-containing anions have been studied in detail; however, ionic liquids with other cations and anions continue to be discovered. This review is limited to the literature from 2000 to 2005 dealing with ionic liquids with fluorine-containing anions.
Linear and nonlinear response of a rotating tokamak plasma to a resonant error-field

An in-depth investigation of the effect of a resonant error-field on a rotating, quasi-cylindrical, tokamak plasma is preformed within the context of constant-ψ, resistive-magnetohydrodynamical theory. General expressions for the response of the plasma at the rational surface to the error-field are derived in both the linear and nonlinear regimes, and the extents of these regimes mapped out in parameter space. Torque-balance equations are also obtained in both regimes. These equations are used to determine the steady-state plasma rotation at the rational surface in the presence of the error-field. It is found that, provided the intrinsic plasma rotation is sufficiently large, the torque-balance equations possess dynamically stable low-rotation and high-rotation solution branches, separated by a forbidden band of dynamically unstable solutions. Moreover, bifurcations between the two stable solution branches are triggered as the amplitude of the error-field is varied. A low- to high-rotation bifurcation is invariably associated with a significant reduction in the width of the magnetic island chain driven at the rational surface, and vice versa. General expressions for the bifurcation thresholds are derived and their domains of validity mapped out in parameter space.
Heterocycle synthesis by copper facilitated addition of heteroatoms to alkenes, alkynes and arenes

The de nouvo synthesis of small organic heterocyclic molecules has benefited from recent protocols for copper-facilitated additions of heteroatoms to alkenes, alkynes and arenes. This tutorial review summarizes a number of these recent contributions. Copper salts can facilitate bond formations due to their ability to serve as Lewis acids, oxidizing agents and transition metal catalysts. The current understanding of the mechanisms of these reactions is presented. This review should be of interest to chemists involved in the synthesis of heterocycles and those investigating transition metal facilitated reactions.
Current Reconstruction Techniques for Survivable Three-Phase PWM Converters

In high-performance three-phase pulsewidth-modulated (PWM) converter systems used in generator and motor drives, failure of current sensors will directly interrupt the system performance, and will even cause disastrous consequences. Redundancy in design is one of the popular choices to overcome this issue. However, this usually leads to an undesirable increase in size and cost. This letter presents two novel model-independent current reconstruction methods for three-phase PWM converter systems based on space vector modulation. Using the proposed sensor placement and software algorithm, phase currents within a three-phase converter can be reconstructed to an acceptable level of accuracy under single-survived-sensor (S 3) scenario. A hardware prototype is built and fault tolerant algorithm is implemented using a DSP (TMS320F2812). Experiments are conducted under worst-case scenario to verify the flexibility of sensor placement/converter layout and software algorithm.
The Influence of Leading-Edge Load Alleviation on Supersonic Wing Design

A theoretical and experimental program to assess the effect of leading-edge load constraints on wing design and performance was conducted. For a planform characterized by a highly swept leading edge on the inboard region, linear theory was used to design camber surfaces which produced minimum drag-due-to-lift at the design lift coefficient of 0.08 and a design Mach number of 2.4. In an effort to delay the formation of leading edge vortices which often occur on highly swept wings, two approaches were used in the design criteria to limit the loadings on the leading edge. One wing was constrained to have the normal Mach number less than one everywhere along the leading edge and the second wing was constrained to have a pressure coefficient of zero on the leading edge. Force tests were run on the two constrained wings, on a flat reference wing and on an optimized wing with no leading edge constraints. All wings had identical planforms and thicknesses and were tested over a range of Mach numbers from 1.8 to 2.8 and a range in angles of attack from -5 deg to 8 deg. A comparison of the experimental performance of these four models is shown. Correlations of these results with theoretical predictions and flow visualization photographs are also included.
Horizon dependence of utility optimizers in incomplete models

This paper studies the utility maximization problem with changing time horizons in the incomplete Brownian setting. We first show that the primal value function and the optimal terminal wealth are continuous with respect to the time horizon T. Secondly, we exemplify that the expected utility stemming from applying the T-horizon optimizer on a shorter time horizon S<T may fail to converge to the T-horizon value as S↑T. Finally, we provide necessary and sufficient conditions preventing the existence of this phenomenon.
Improved Synthesis of γ-Lactones from Cyclopropyl Cyanoesters

Abstract Cyclopropyl cyanoesters 2 were reliably converted to γ-lactones 4 on treatment with aqueous sulfuric acid. The cyanoesters could be easily prepared from ketones or aldehydes in two steps, making this process particularly attractive from an efficiency standpoint.
An Expeditious Route to Monoprotected α-Keto Aldehydes with Control of Regiochemistry

Abstract Treatment of representative orthoesters (2) with pyruvonitrile (3) afforded the corresponding α, α-diethoxynitriles (4) in 65–80% yields. Subsequent reduction of the latter using lithium aluminum hydride, followed by careful hydrolysis of the aldimine intermediates, led to the procurement of α, α-dialkoxy aldehydes (5) in 80–90% yield.
On the derivation of well posed boundary value problems in structural mechanics

Abstract The paper starts with a discussion of a number of published boundary value problems in structural mechanics, whose intuitive formulation led to incorrect boundary or matching conditions. It is then shown on three examples, using variational methods, how to obtain well posed formulations for problems of this type. For uniformity of presentation, all examples deal with continuously supported beams. The first two examples exhibit boundary and matching points whose position is fixed along the beam axis. In the third example it is shown how to use the method of variational calculus for a variable end point to formulate structural problems with variable matching points. This is demonstrated on the problem of a beam which rests on, but is not attached to, a Pasternak base; thus where parts of the beam may lift off the base. Each example concludes with a comparison and discussion of related formulations published in the literature.
Vehicle Occupancy and Crash Risk

This study explores the association between vehicle occupancy and a driver's risk of causing a fatal crash, not wearing a seat belt, and using alcohol. The survey population is the set of drivers represented in the Fatal Analysis Reporting System for 1992 to 2002. The independent variables are driver age, driver gender, passenger age, passenger gender, and vehicle occupancy. The outcome variables are whether the driver was at fault in causing the fatal crash, whether the driver wore a seat belt, and whether the driver had used alcohol. For male teenage drivers, driving with teenage passengers correlated with an increased risk of causing a crash. For all female drivers and for male drivers over age 40, passenger presence correlated with a reduced risk of causing a fatal crash. Drivers ages 15 to 30 were less likely to wear a seat belt when passengers were present than when driving solo. Drivers age 50 and older had higher rates of seat belt use when passengers were present. This protective effect of passen...
Interstellar Turbulence I: Observations and Processes

▪ Abstract Turbulence affects the structure and motions of nearly all temperature and density regimes in the interstellar gas. This two-part review summarizes the observations, theory, and simulations of interstellar turbulence and their implications for many fields of astrophysics. The first part begins with diagnostics for turbulence that have been applied to the cool interstellar medium and highlights their main results. The energy sources for interstellar turbulence are then summarized along with numerical estimates for their power input. Supernovae and superbubbles dominate the total power, but many other sources spanning a large range of scales, from swing-amplified gravitational instabilities to cosmic ray streaming, all contribute in some way. Turbulence theory is considered in detail, including the basic fluid equations, solenoidal and compressible modes, global inviscid quadratic invariants, scaling arguments for the power spectrum, phenomenological models for the scaling of higher-order structu...
THE EFFECTS OF FEDERAL TRANSIT SUBSIDY POLICY ON INVESTMENT DECISIONS: THE CASE OF SAN FRANCISCO'S GEARY CORRIDOR

In the United States, federal funding for public transit often accounts for a large proportion of a local agency's budget, especially for capital investments. For this reason, local governments can be expected to plan a portfolio of projects that maximize federal contributions. This study examines the financial effects of federal transit subsidy policy on local transit investment decisions. Data from a System Planning Study for the Geary Corridor in San Francisco are used as an illustration. It is found that federal transit subsidy policy provides financial incentives for local decision-makers to select capital-intensive investment options that may not be efficient or effective. While federal financial incentives are not the only factor influencing local investment decisions, some reform of the current subsidy policy may be necessary to reduce the incentive for ineffective use of public resources.
Moving from an Exception to a Rule: Analyzing Mechanisms in Emergence-Based Institutionalization

We analyze the conditions under which a practice moves from rare and unacceptable to preponderant and legitimate through bottom-up, relational processes. To better understand the mechanisms and contingencies of such "emergence-based institutionalization," we combine computational agent-based modeling with insights from a setting where a seemingly deviant local practice became institutionalized: the case of the emergence of proprietary disclosure in the academic life sciences. Our approach results in both theoretical and methodological contributions. From a theoretical perspective, we develop propositions related to microlevel processes that lead to the institutionalization of new rules or those that leave existing arrangements unchanged. Our analysis suggests that traditional social explanations, such as organizational reproduction and copying successful peers, are less likely to drive emergence-based institutionalization than cognitive factors that direct individuals to anticipate and preempt the actions of others. From a methodological perspective, we provide an example of how case analysis and computational modeling can be combined to study the varying and contingent roles that normative, social, and cognitive factors play in persistence and change in institutionalization.
A $q$-analog of Ljunggren's binomial congruence

We prove a $q$-analog of a classical binomial congruence due to Ljunggren which states that $\binom{ap}{bp} \equiv \binom{a}{b}$ modulo $p^3$ for primes $p \geq 5$. This congruence subsumes and builds on earlier congruences by Babbage, Wolstenholme and Glaisher for which we recall existing $q$-analogs. Our congruence generalizes an earlier result of Clark.
Kernel estimation of the instantaneous frequency

Considers kernel estimators of the instantaneous frequency of a slowly evolving sinusoid in white noise. The expected estimation error consists of two terms. The systematic bias error grows as the kernel halfwidth increases while the random error decreases. For a nonmodulated signal g(t), the kernel halfwidth that minimizes the expected error is proportional to h/spl sim/[(/spl sigma//sup 2/)/(N|/spl part//sub t//sup 2/g|2)]/sup 1/5/ where /spl sigma//sup 2/ is the noise variance and N is the number of measurements per unit time. The author shows that estimating the instantaneous frequency corresponds to estimating the first derivative of a modulated signal, A(t)exp(i/spl phi/(t)). For instantaneous frequency estimation, the halfwidth which minimizes the expected error is larger: h/sub 1,3//spl sim/[(/spl sigma//sup 2/)/(A/sup 2/N|/spl part//sub t//sup 3/(e/sup i/spl phi/~(t/))|/sup 2/)]/sup 1//$ u7. Since the optimal halfwidths depend on derivatives of the unknown function, the authors initially estimate these derivatives prior to estimating the actual signal. >
Elicitation for aggregation

We study the problem of eliciting and aggregating probabilistic information from multiple agents. In order to successfully aggregate the predictions of agents, the principal needs to elicit some notion of confidence from agents, capturing how much experience or knowledge led to their predictions. To formalize this, we consider a principal who wishes to learn the distribution of a random variable. A group of Bayesian agents has each privately observed some independent samples of the random variable. The principal wishes to elicit enough information from each agent, so that her posterior is the same as if she had directly received all of the samples herself. Leveraging techniques from Bayesian statistics, we represent confidence as the number of samples an agent has observed, which is quantified by a hyperparameter from a conjugate family of prior distributions. This then allows us to show that if the principal has access to a few samples, she can achieve her aggregation goal by eliciting predictions from agents using proper scoring rules. In particular, with access to one sample, she can successfully aggregate the agents' predictions if and only if every posterior predictive distribution corresponds to a unique value of the hyperparameter, a property which holds for many common distributions of interest. When this uniqueness property does not hold, we construct a novel and intuitive mechanism where a principal with two samples can elicit and optimally aggregate the agents' predictions.
A versatile set of aminooxy amino acids for the synthesis of neoglycopeptides.

Four N-alkylaminooxy amino acids have been synthesized in 22−56% overall yield from readily available amino acid precursors. Each amino acid can be efficiently incorporated into peptides using Boc-chemistry-based solid-phase peptide synthesis, and in three of the four cases the resulting peptides can be chemoselectively glycosylated at the aminooxy side chains to generate neoglycopeptides. The range of N-alkylaminooxy amino acids prepared allows attachment of sugars at two-, three-, or four-atom distances from the peptide backbone, and each ensures that attached sugars adopt cyclic conformations. These derivatives provide convenient access to arrays of biologically relevant neoglycopeptides that may be used to probe the influence of attached sugars on the structure and function of peptides and proteins.
An Airspeed Vector Sensor for V/STOL Aircraft

For some years a technique for airspeed sensing using the ion beam of the positive corona discharge has been under development at Princeton University. This technique employs ions in transit across an electrode gap; these may be deflected by airflow during their transit, and by measuring the deflection one can determine the flow rate. In most ion sensors the relationship is linear and very accurate, which makes this technique particularly suited to low speed sensing. With the specific requirements of V/STOL aircraft in mind, we have applied this technique to airspeed vector sensing, that is, simultaneous resolution and measurement of three airspeed components. Our research has led to a prototype sensor which has demonstrated the following characteristics in wind-tunnel tests: 1) a response to each flow component which is linear and virtually insensitive to temperature and humidity variations; 2) little coupling between the three responses; 3) a maximum measurable speed of 50 m/s, which may easily be increased; and 4) an accuracy on the order of 0.01-0.1 m/s. The sensor is fairly light, and has no moving parts. The paper includes discussion of the principles of the sensing technique, the testing of our prototype, and means for further refinement.
The People's Budget? Politics, Participation and Pro-poor Policy

Recent moves towards ‘participatory’ budgeting have raised hopes and expectations that spending and revenue generation can be made more pro-poor if informed citizens and their non-traditional political organizations participate directly in budgeting decisions. This article reviews experiences of participatory budgeting and pro-poor policy-making in Brazil, Ireland, Chile, Mauritius, and Costa Rica. It draws attention to several important issues: Who participates? What kind of institutional framework is necessary? What happened to the revenue-generation side of pro-poor budgeting? It points out that making spending and taxation more ‘pro-poor’ has historically depended on pro-poor political parties gaining power.
Design and synthesis of tridentate facially chelating ligands of the [2.n.1]-(2,6)-pyridinophane family.

Syntheses are reported for tripyridine macrocycles 2 and 3 and some of their alkyl derivatives. The macrocycles are designed to stabilize to various extents coordinated d(8) metal precursors and d(6) alkane oxidative addition products (Pt(IV)), therefore allowing favorable kinetics and thermodynamics of (e.g., Pt(II)) the cleavage of substrate H-C(sp(3)) bonds. Both the Chichibabin protocol and oxidative coupling of carbanions by copper(I) iodide were used for the macrocyclization step. Crystal structures of singly and doubly protonated 2 establish atom connectivity in the macrocycle, and reveal structural features which are obscured in solution NMR by rapid proton migration.
Commutative idempotent groupoids and the constraint satisfaction problem

A restatement of the Algebraic Dichotomy Conjecture, due to Maroti and McKenzie, postulates that if a finite algebra A possesses a weak near-unanimity term, then the corresponding constraint satisfaction problem is tractable. A binary operation is weak near-unanimity if and only if it is both commutative and idempotent. Thus if the dichotomy conjecture is true, any finite commutative, idempotent groupoid (CI groupoid) will be tractable. It is known that every semilattice (i.e., an associative CI groupoid) is tractable. A groupoid identity is of Bol–Moufang type if the same three variables appear on either side, one of the variables is repeated, the remaining two variables appear once, and the variables appear in the same order on either side (for example, \({x(x(yz)) \approx (x(xy))z}\)). These identities can be thought of as generalizations of associativity. We show that there are exactly 8 varieties of CI groupoids defined by a single additional identity of Bol–Moufang type, derive some of their important structural properties, and use that structure theory to show that 7 of the varieties are tractable. We also characterize the finite members of the variety of CI groupoids satisfying the self-distributive law \({x(yz) \approx (xy)(xz)}\), and show that they are tractable.
From cradle to grave: How to loot a 401(k) plan

Abstract The regulations governing asset distributions from many retirement plans give participants the option to time retirement or rollovers from the plan strategically. They possess a long-lived put option, whose exercise price resets periodically to the current value of the assets in the plan. I derive a recursive closed-form valuation formula for the option and develop a numerical algorithm for implementing the result. I find that, for reasonable assumptions about volatility and life expectancy, the option's value may approach 40% of the value of the assets in the plan, financed entirely by those still contributing. This wealth transfer can, however, be easily avoided by making a simple change to the current regulations governing valuation and payout of these retirement plans.
Synthesis of 4-aryl- and 4-alkyl-2-silyl-1,3-butadienes and their Diels-Alder/cross-coupling reactions.

An ene-yne cross methasis of silyl-substituted alkynes and alkenes has been developed as a route to 4-aryl- and 4-alkyl-2-silyl-substituted 1,3-dienes. The dienes prepared were used to affect highly diastereoselective Diels−Alder reactions and then the silicon-substituted Diels−Alder cycloadducts were used in Hiyama cross-coupling reactions. The cross-coupling reactions enable these silicon dienes to be used as synthons for a variety of other dienes one might prepare and need access to. Two of the silicon-substituted Diels−Alder cycloadducts and one of the Hiyama cross-coupling products were also characterized by X-ray crystallography.
On Another Edge of Defocusing: Hyperbolicity of Asymmetric Lemon Billiards

Defocusing mechanism provides a way to construct chaotic (hyperbolic) billiards with focusing components by separating all regular components of the boundary of a billiard table sufficiently far away from each focusing component. If all focusing components of the boundary of the billiard table are circular arcs, then the above separation requirement reduces to that all circles obtained by completion of focusing components are contained in the billiard table. In the present paper we demonstrate that a class of convex tables—asymmetric lemons, whose boundary consists of two circular arcs, generate hyperbolic billiards. This result is quite surprising because the focusing components of the asymmetric lemon table are extremely close to each other, and because these tables are perturbations of the first convex ergodic billiard constructed more than 40 years ago.
A Collaborative Mechanism for Crowdsourcing Prediction Problems

Machine Learning competitions such as the Netflix Prize have proven reasonably successful as a method of "crowdsourcing" prediction tasks. But these competitions have a number of weaknesses, particularly in the incentive structure they create for the participants. We propose a new approach, called a Crowdsourced Learning Mechanism, in which participants collaboratively "learn" a hypothesis for a given prediction task. The approach draws heavily from the concept of a prediction market, where traders bet on the likelihood of a future event. In our framework, the mechanism continues to publish the current hypothesis, and participants can modify this hypothesis by wagering on an update. The critical incentive property is that a participant will profit an amount that scales according to how much her update improves performance on a released test set.
Palladium‐Catalyzed Stille Cross‐Coupling Reaction of Aryl Chlorides using a Pre‐Milled Palladium Acetate and XPhos Catalyst System

A highly active catalyst system based upon a biaryl monophosphine ligand, XPhos, for the palladium-catalyzed Stille reaction has been developed. This method allows for the coupling of aryl chlorides with a range of tributylarylstannanes to produce the corresponding biaryl compounds in good to excellent yields (61-98%) in short reaction times (4h). Palladium(II) acetate [Pd(OAC) 2 ] and XPhos in a 1:1.1 ratio were milled into a fine powder that was used as pre-catalyst for these reactions.
Examining Comparative Shopping Agents from Two Types of Search Results

When searching for products and information using search engines, Web consumers often see comparative shopping agents (CSAs) in search results. CSAs list companies that sell desired products and the prices they offer on one page, greatly reducing search costs. Using 168 digital camera models from seven major camera makers, we examine CSAs between organic and paid search results in terms of the number of CSAs, number of vendors, lowest and average prices, and price dispersion.