cssi/SciSciGPT-SciSciNet huggingface dataset:
Against Parsimony: Three Easy Ways of Complicating Some Categories of Economic Discourse

Economics as a science of human behavior has been grounded in a remarkably parsimonious postulate: that of the self-interested, isolated individual who chooses freely and rationally between alternative courses of action after computing their prospective costs and benefits. In recent decades, a group of economists has shown considerable industry and ingenuity in applying this way of interpreting the social world to a series of ostensibly noneconomic phenomena, from crime to the family, and from collective action to democracy. The “economic” or “rational-actor” approach has yielded some important insights, but its onward sweep has also revealed some of its intrinsic weaknesses. As a result, it has become possible to mount a critique which, ironically, can be carried all the way back to the heartland of the would-be conquering discipline. That the economic approach presents us with too simpleminded an account of even such fundamental economic processes as consumption and production is the basic thesis of the present paper.
A CONJUGATE ADDITION-ELIMINATION ROUTE TO ALKENOYLTRIMETHYLSILANES

Abstract Monosubstitution of 3,3-dichloro-1-(trimethylsilyl)-2-propenone (1) with organocuprates stereoselectively affords E -3-alkyl- and Z-3-phenyl-3-chloro-1-(trimethylsilyl)-2-propenones. Further substitution proceeds stereoselectively as a function of extant and incoming substituents. 1 was also reduced to E -3-chloro-1-(trimethylsilyl)-2-propenone and the latter converted to E -3-alkyl- and E -3-phenyl-1-(trimethylsilyl)-2-propenones.
Shocks, Crises, and Their Determinants

The current global financial crisis is the most serious both in terms of magnitude and in terms of scope since the Great Depression. No country has been immune to the economic slowdown. In advanced economies, the financial crisis and the global recession that followed the burst of the global financial bubble have brought severe consequences in terms of employment and output. In developing countries, output contraction, growth slowdown, and rising unemployment have come hand in hand with higher borrowing costs, sluggish export growth, and a significant reduction in international capital flows. As a result, poverty has increased. The global financial crisis has left lasting effects on the structure of financial markets, international capital flows, and the cost of capital for developing countries. The efforts of governments and international financial institutions to buffer the impact of the crisis have been quick and aimed in the right direction. However, many risks remain for the road to recovery. This pa...
Demand for Carsharing Systems in Beijing, China: An Exploratory Study

Rising auto ownership in China brings significant urban and environmental challenges. Since China is still in the early stages of motorization, there are opportunities to introduce alternatives to personal vehicle ownership. The authors conducted a survey with 800 Beijing residents, collecting data on transportation patterns, automobile ownership, environmental attitudes, and carsharing response. Fifteen of those participants were selected to complete an in-depth questionnaire discussing how they would use carsharing services. This paper assesses the potential for carsharing systems within Beijing, China, based on this exploratory study. While the results suggest that carsharing models integrated into existing transit networks could become an important mobility option within China's rapidly growing cities, further study is recommended.
Construction of doubly-periodic instantons

We construct finite-energy instanton connections over ℝ4 which are periodic in two directions via an analogue of the Nahm transform for certain singular solutions of Hitchin's equations defined over a 2-torus.
Mars Photoelectron Energy and Pitch Angle Dependence on Intense Lower Atmospheric Dust Storms

We have conducted a survey of the Mars Global Surveyor (MGS) electron data across all the pitch angles of 12 usable energy bins (11–746 eV) for dayside photoelectron observations over regions of strong crustal fields. Studies have shown that solar EUV flux is the main controlling factor, but dust storms play an important role as well. Our study of different energies and pitch angles has shown that the unusual bimodal solar flux dependence is not a common feature but mainly found in low energies and a few bins of higher-energy channels. By multiplying time-history dust opacity with a solar EUV proxy as a new controlling function, the statistically significant increase of the correlation of photoelectron flux against this function indicates that dust storms have a long-lasting influence on high-altitude photoelectron fluxes, especially at low energies and the pitch angle source regions of high-energy channels. The correlation increases experienced by the pitch angle source regions of all examined energy channels suggest that dust storms' influence most likely happens in the thermosphere-ionosphere source region of the photoelectrons, rather than at exospheric altitudes at or above MGS. Furthermore, by isolating the global-scale dust storm in Mars year 25 (2001) from the rest, the results suggest that this storm is entirely responsible for the second solar flux-dependent trend. While not excluding the possibility of this phenomenon being a one-time event, we hypothesize that there is a threshold of dust opacity at which the low-altitude dust's influence on high-altitude photoelectron fluxes begins to be significant.
An exact algorithm for graph partitioning

An exact algorithm is presented for solving edge weighted graph partitioning problems. The algorithm is based on a branch and bound method applied to a continuous quadratic programming formulation of the problem. Lower bounds are obtained by decomposing the objective function into convex and concave parts and replacing the concave part by an affine underestimate. It is shown that the best affine underestimate can be expressed in terms of the center and the radius of the smallest sphere containing the feasible set. The concave term is obtained either by a constant diagonal shift associated with the smallest eigenvalue of the objective function Hessian, or by a diagonal shift obtained by solving a semidefinite programming problem. Numerical results show that the proposed algorithm is competitive with state-of-the-art graph partitioning codes.
Rate enhancement of the Morita–Baylis–Hillman reaction through mechanochemistry

Through the novel technique of high speed ball milling we were able to generate Baylis–Hillman products in as little as 0.5 hours. This represents one of the fastest methods of Baylis–Hillman reactions under neat conditions. Upon analysis of various catalysts we found 1,4-diazabicyclo[2.2.2]octane to be the catalyst that led to the highest product yields in the shortest reaction time.
Intermetallics for permanent magnets

Going back as far as 1931, it is shown by the examples MnAl, Fe-Nd, Fe-Nd-B, and Fe(-Ti)-Sm how the history of permanent magnet materials might have evolved differently if hints had been heeded that were discernible long before a particular magnet development actually began. The author reports the lessons learned, discusses the directions being taken in the exploration of multicomponent alloy systems, and suggests ways to search for intermetallics that are potential permanent magnet materials. >
Generalized Belief Propagation on tree robust structured region graphs

This paper provides some new guidance in the construction of region graphs for Generalized Belief Propagation (GBP). We connect the problem of choosing the outer regions of a Loop-Structured Region Graph (SRG) to that of finding a fundamental cycle basis of the corresponding Markov network. We also define a new class of tree-robust Loop-SRG for which GBP on any induced (spanning) tree of the Markov network, obtained by setting to zero the off-tree interactions, is exact. This class of SRG is then mapped to an equivalent class of tree-robust cycle bases on the Markov network. We show that a tree-robust cycle basis can be identified by proving that for every subset of cycles, the graph obtained from the edges that participate in a single cycle only, is multiply connected. Using this we identify two classes of tree-robust cycle bases: planar cycle bases and "star" cycle bases. In experiments we show that tree-robustness can be successfully exploited as a design principle to improve the accuracy and convergence of GBP.
Divergent reaction pathways for phenol arylation by arynes: synthesis of helicenes and 2-arylphenols

Two reactions of phenols with arynes have been developed. If LiTMP base is employed, arynes generated from aryl chlorides react with phenols to form helicenes. o-Arylation of phenols can be achieved by employing tBuONa base in the presence of AgOAc. Direct arylation of binol was achieved leading to the shortest pathway to o,o′-diarylbinols.
Guesswork and common sense: the alphabetic reference design process for Microsoft Works

It has been found that the Microsoft alphabetic reference paradigm is a flexible model for documenting software applications. It makes it possible to tailor manuals to a diverse range of software, reduce page count, and provide a usable tool for serial (step-by-step) and holistic (concept-oriented) learners. After discussing reference organization considerations and paradigm options, the author describes the modified alphabetic paradigm for the Microsoft Works Reference. >
Club networks with multiple memberships and noncooperative stability

Modeling club structures as bipartite directed networks, we formulate the problem of club formation with multiple memberships as a noncooperative game of network formation and identify conditions on network formation rules and players' network payoffs sufficient to guarantee that the game has a potential function. Our sufficient conditions require that each player choose freely and unilaterally those clubs he joins and also his activities within those clubs (subject to feasibility constraints). We refer to our conditions on rules as noncooperative free mobility. We also require that players' payoffs be additively separable in player-specific payoffs and externalities and that payoff externalities — a function of club membership, club activities, and crowding — be identical across players (externality homogeneity). We then show that under these conditions, the noncooperative game of club network formation with multiple memberships is a potential game over directed club networks and we discuss the implications of this result.
The stratified Boycott effect

We present the results of an experimental investigation of the flows generated by monodisperse particles settling at low Reynolds number in a stably stratified ambient with an inclined sidewall. In this configuration, upwelling beneath the inclined wall associated with the Boycott effect is opposed by the ambient density stratification. The evolution of the system is determined by the relative magnitudes of the container depth, ; subsequently, smaller overlying layers develop. Within each layer, convection erodes the initially linear density gradient, generating a step-like density profile throughout the system that persists after all the particles have settled. Particles are transported across the discrete density jumps between layers by plumes of particle-laden fluid.
A graph theoretic approach to utilizing protein structure to identify non-random somatic mutations

Background It is well known that the development of cancer is caused by the accumulation of somatic mutations within the genome. For oncogenes specifically, current research suggests that there is a small set of "driver" mutations that are primarily responsible for tumorigenesis. Further, due to recent pharmacological successes in treating these driver mutations and their resulting tumors, a variety of approaches have been developed to identify potential driver mutations using methods such as machine learning and mutational clustering. We propose a novel methodology that increases our power to identify mutational clusters by taking into account protein tertiary structure via a graph theoretical approach.
Search for New Physics at the Tevatron

Over the past three decades the Standard Model (SM) of particle physics has been surprisingly successful. Although the precision of experimental tests improved by orders of magnitude no significant deviation from the SM predictions has been observed so far. Still, there are many questions that the Standard Model does not answer and problems it can not solve. Among the most important ones are the origin of the electro-weak symmetry breaking, hierarchy of scales, unification of fundamental forces and the nature of gravity. Recent cosmological observations indicates that the SM particles only account for 4% of the matter of the Universe. Many extensions of the SM (Beyond the Standard Model, BSM) have been proposed to make the theory more complete and solve some of the above puzzles. Some of these extension includes SuperSymmetry (SUSY), Grand Unification Theory (GUT) and Extra Dimensions. At CDF [1] and D0 [2] we search for evidence of such processes in proton-antiproton collisions at \( \sqrt {(s)} \) = 1980 GeV. The phenomenology of these models is very rich, although the cross sections for most of these exotic processes is often very small compared to those of SM processes at hadron colliders. It is then necessary to devise analysis strategies that would allow to disentagle the small interesting signals, often buried under heavy instrumental and SM background.
A five element basis for the uncountable linear orders

In this paper I will show that it is relatively consistent with the usual axioms of mathematics (ZFC) together with a strong form of the axiom of infinity (the existence of a supercompact cardinal) that the class of uncountable linear orders has a five element basis. In fact such a basis follows from the Proper Forcing Axiom, a strong form of the Baire Category Theorem. The elements are X, ¥o1, ¥o.1, C, C. where X is any suborder of the reals of cardinality .1 and C is any Countryman line. This confirms a longstanding conjecture of Shelah.
A stabilization technique for phase-locked frequency synthesizers

A stabilization technique is presented that relaxes the tradeoff between the settling speed and the magnitude of output sidebands in phase-locked frequency synthesizers. The method introduces a zero in the open-loop transfer function through the use of a discrete-time delay cell, obviating the need for resistors in the loop filter. A 2.4-GHz CMOS frequency synthesizer employing the technique settles in approximately 60 /spl mu/s with 1-MHz channel spacing while exhibiting a sideband magnitude of -58.7 dBc. Designed for Bluetooth applications and fabricated in a 0.25-/spl mu/m digital CMOS technology, the synthesizer achieves a phase noise of -112 dBc/Hz at 1-MHz offset and consumes 20 mW from a 2.5-V supply.
Evaluating housing quality, health and safety using an Internet-based data collection and response system: a cross-sectional study.

Typically housing and health surveys are not integrated together and therefore are not representative of population health or national housing stocks. In addition, the existing channels for distributing information about housing and health issues to the general public are limited. The aim of this study was to develop a data collection and response system that would allow us to assess the Finnish housing stock from the points of view of quality, health and safety, and also to provide a tool to distribute information about important housing health and safety issues. The data collection and response system was tested with a sample of 3000 adults (one per household), who were randomly selected from the Finnish Population Register Centre. Spatial information about the exact location of the residences (i.e. coordinates) was included in the database inquiry. People could participate either by completing and returning a paper questionnaire or by completing the same questionnaire via the Internet. The respondents did not receive any compensation for their time in completing the questionnaire. This article describes the data collection and response system and presents the main results of the population-based testing of the system. A total of 1312 people (response rate 44%) answered the questionnaire, though only 80 answered via the Internet. A third of the respondents had indicated they wanted feedback. Albeit a majority (>90%) of the respondents reported being satisfied or quite satisfied with their residence, there were a number of prevalent housing issues identified that can be related to health and safety. The collected database can be used to evaluate the quality of the housing stock in terms of occupant health and safety, and to model its association with occupant health and well-being. However, it must be noted that all the health outcomes gathered in this study are self-reported. A follow-up study is needed to evaluate whether the occupants acted on the feedback they received. Relying solely on an Internet-based questionnaire for collecting data would not appear to provide an adequate response rate for random population-based surveys at this point in time.
A dynamic information-structure mutual exclusion algorithm for distributed systems

A dynamic information-structure mutual exclusion algorithm is presented for distributed systems whose information-structure evolves with time as sites learn about the state of the system through messages. An interesting feature of the algorithm is that it adapts itself to heterogeneous or fluctuating traffic conditions to optimize the performance (the number of messages exchanged). The performance of the algorithm is studied by simulation technique and compared to the performance of a well-known mutual exclusion algorithm. The impact message loss and site failures on the algorithm is discussed and methods to tolerate these failures are proposed. >
The pure rotational spectrum of the actinide-containing compound thorium monoxide

The J = 1–0 pure rotational transition, together with hyperfine structure where appropriate, has been recorded for all three naturally occurring isotopomers of the actinide-containing compound thorium monoxide (232Th16O, 232Th17O and 232Th18O).
Drugs, Guns, and Disadvantaged Youths Co-Occurring Behavior and the Code of the Street

Guided by Anderson’s theory of the code of the street, this study explored social mechanisms linking individual-level disadvantage factors with the adoption of beliefs grounded in the code of the street and with drug trafficking and gun carrying—the co-occurring behavior shaping violence among young men in urban areas. Secondary data were employed from a sample of male inmates and a sample of male high school students. Data analysis indicated that the social disadvantage factor absent father significantly predicted this co-occurring behavior in the inmate sample, whereas the social disadvantage factor history of expulsion did so in the student sample. In both samples, race and adopting beliefs about gun carrying from the code of the street were significant predictors of drug trafficking and gun carrying. The results do not suggest that such code-based beliefs’ impact on drug trafficking and gun carrying differs by race. Implications for social policy are discussed.
Beyond technology-push and demand-pull: Lessons from California's solar policy

Abstract The scale of the technological transformation required to reduce greenhouse gas emissions to “safe” levels while minimizing economic impacts necessitates an emphasis on designing climate policy to foster, or at least not impede, environmental innovation. There is only a weak empirical base for policy-makers to stand on regarding the comparative innovation effects of various climate policy options, however. Empirical scholarship in environmental innovation is hindered by the complexity of both the innovation process and the interactions between the dual market failures of pollution and innovation that are in play, and it appears that the field would benefit from the structure provided by a common lexicon. This paper focuses on the issues related to policy categorization in this field; these issues have received little attention in the literature despite their importance to making insights gained from empirical studies generalizable. The paper reviews the origins, strengths, and weaknesses of the dominant policy typology of technology-push versus demand-pull instruments. Its primary contribution, however, is to assemble a comprehensive chronology of solar policy in California and its impacts on innovation, where known, and then use this as a basis for building a new policy categorization that takes advantage of the intuitive resonance of the dominant typology, while encompassing the broader range of policy instruments that are employed in practice in order to stimulate environmental innovation. The most noteworthy aspect of the new categorization is that it introduces a third category of environmental innovation policy instrument that focuses on improving the interface between technology suppliers and users. This reflects developments in the economics of innovation literature as well as considerable evidence in the domain of distributed solar energy technologies that opportunism by some of the actors that work at this interface can be a barrier to innovation.
Simultaneous-Perturbation-Stochastic-Approximation Algorithm for Parachute Parameter Estimation

This paper presents an algorithm to estimate unknown parameters of parachute models from flight-test data. The algorithm is based on the simultaneous-perturbation-stochastic-approximation method to minimize the prediction error (difference between model output and test data). The algorithm is simple to code and requires only the model output. Analytical gradients are not necessary. The algorithm is used to estimate aerodynamic and apparent mass coefficients for an existing parachute model.
Understanding Overbidding in Second Price Auctions: An Experimental Study*

We present results from second price private value auction (SPA) experiments where bidders may receive noisy signals about their opponentsvalue. Such signals change biddersperception about the � strengthof their opponent, and the relationship between biddersperception of their opponent and overbidding provides a novel channel to understand overbidding in SPA. We found that small and medium overbids are more likely to occur when bidders perceive their rivals to have similar values, supporting a modifiedjoy of winninghypothesis but large overbids are more likely to occur when bidders believe their opponents to have much higher values, consistent with thespite� hypothesis. Second price private value auctions (SPAs) are the most easily understood auction format from a theoretical point of view. 1 In standard private value auction models of fully rational bidders with standard preferences, bidding one's own value is a weakly dominant strategy. This theoretical prediction holds irrespective of biddersrisk atti- tudes, the number of rival bidders, symmetry in the value distributions and so on. In laboratory experiments, however, subjects are found to exhibit a consistent pattern of overbidding. Kagel et al. (1987) found that the actual bids are on average 11% above the dominant strategy bids. Kagel and Levin (1993) found that about 62% of all bids in their five-bidder SPA sessions exceed the bidder's value, while only 8% of all bids were below it. Both Kagel and Levin (1993) and Harstad (2000) further reported that experience has only a small effect in reducing overbidding in SPA. An important related finding is that overbidding in English auctions, a mechanism that is strategically equivalent to the SPA in the case of private values, is known to be a short-term phenomenon that subjects quickly learn not to undertake (Kagel and Levin 1993). Thus any explanation for the prevalence and persistence of overbidding in the SPA must also explain its rarity in the English auction. Given the robustness of the findings of overbidding in SPA, it is surprising that economists have little understanding of why it happens. Kagel et al. (1987) conjectured that bidding above one's own value in a SPA is based on the illusion that it improves the probability of winning with little cost because the winner only pays the second-highest bid. 2 Moreover, they argue that overbidding is sustainable because bidders still on average earn positive profits and because the negative feedback from overbidding is a weak mechanism in the SPA. For example, if a bidder overbids in a SPA by 10% above her value, it is quite possible that she does not win at all and thus does not experience
Deriving cloud velocity from an array of solar radiation measurements

Spatio-temporal variability of solar radiation is the main cause of fluctuating photovoltaic power feed-in to the grid. Clouds are the dominant source of such variability and their velocity is a principal input to most short-term forecast and variability models. Two methods are presented to estimate cloud speed using radiometric measurements from 8 global horizontal irradiance sensors at the UC San Diego Solar Energy test bed. The first method assigns the wind direction to the direction of the pair of sensors that exhibits the largest cross-correlation in the irradiance timeseries. This method is considered the ground truth. The second method requires only a sensor triplet; cloud speed and the angle of the cloud front are determined from the time delays in two cloud front arrivals at the sensors. Our analysis showed good agreement between both methods and nearby METAR and radiosonde observations. Both methods require high variability in the input radiation as provided only in partly cloudy skies.
Peptide‐Based Methods for the Preparation of Nanostructured Inorganic Materials

With their unique sequence-specific self-assembly and their substrate recognition properties, peptides play critical roles in controlling the biomineralization of inorganic nanostructures in natural systems and in directing the assembly of important soft matter. These attributes render them particularly useful molecules for the fabrication of new materials. Researchers from many scientific disciplines now use peptides to direct the synthesis of new inorganic nanostructures and the assembly of soft biomaterials. In this Review we describe the developments in this field and focus on the versatility of peptides and their ability to direct the composition and structure of new inorganic materials.
The Quantitative Role of Child Care for Female Labor Force Participation and Fertility

Consistent with facts for a cross-section of OECD countries, I document that the labor force participation rate of West German mothers with children aged zero to two exceeds the corresponding child care enrollment rate whereas the opposite is true for mothers with children aged three to mandatory school age. I develop a life-cycle model that explicitly accounts for this age-dependent relationship through various types of non-paid and paid child care. The calibrated version of the model is used to evaluate two policy reforms concerning the supply of subsidized child care for children aged zero to two. These counterfactual policy experiments suggest that the lack of subsidized child care constitutes indeed for some females a barrier to participate in the labor market and depresses fertility.
Design, Fabrication, and Testing of Ceramic Joints for High Temperature SiC/SiC Composites

Various issues associated with the design and mechanical evaluation of joints of ceramic matrix composites are discussed. The specific case of an affordable, robust ceramic joining technology (ARCJoinT) to join silicon carbide (CG-Nicalon ) fiber-reinforced-chemically vapor infiltrated (CVI) silicon carbide matrix composites is addressed. Experimental results are presented for the time and temperature dependence of the shear strength of these joints in air up to 1200°C. From compression testing of double-notched joint specimens with a notch separation of 4 mm, it was found that the apparent shear strength of the joints decreased from 92 MPa at room temperature to 71 MPa at 1200°C. From shear stress-rupture testing in air at 1200°C it was found that the shear strength of the joints decreased rapidly with time from an initial shear strength of 71 MPa to a value of 17.5 MPa after 14.3 h. The implications of these results in relation to the expected long-term service life of these joints in applications at elevated temperatures are discussed.
Use of Reduced-Order Modeling Procedures for Production Optimization

This paper (SPE 119057) was accepted for presentation at the SPE Reservoir Simulation Symposium, The Woodlands, Texas, USA, 2–4 February 2009, and revised for publication. Original manuscript received for review 21 October 2008. Revised manuscript received for review 18 June 2009. Paper peer approved 27 June 2009. Summary The determination of optimal well settings is very demanding computationally because the simulation model must be run many times during the course of the optimization. For this reason, reduced-order modeling procedures, which are a family of techniques that enable highly efficient simulations, may be very useful for optimization problems. In this paper, we describe a recently developed reduced-order modeling (ROM) technique that has been used in other application areas, the trajectory piecewise linearization (TPWL) procedure, and incorporate it in production-optimization computations. The TPWL methodology represents solutions encountered during the optimization runs in terms of Taylor-series expansions around previously simulated states. This requires a small number of preprocessing (training) simulations using the full (high-fidelity) model, during which pressure and saturation states and Jacobian matrices are saved. These states and matrices are then projected into a low-dimensional space using proper orthogonal decomposition (POD). Simulations in this reduced space can be performed very efficiently; in this work, we observe runtime speedups of a factor of 450. Overall speedups are, however, less because of the preprocessing overhead. We assess the TPWL representation for simulations of waterflood in a heterogeneous 3D model containing more than 20,000 gridblocks and six wells. The high degree of accuracy of the TPWL model is first demonstrated for several testing simulations in which producerand injector-well settings differ from those used in the training runs. The TPWL representations are then used in optimizations involving the determination of optimal bottomhole pressures (BHPs) for a reservoir model with four production wells and two injection wells. A gradient-based algorithm is applied for the optimizations. In the first case, the BHPs of the producers and injectors are optimized at six different times (36 control variables) and in the second case at 15 different times (90 control variables). Results for optimized net present value (NPV) using TPWL are shown to be in consistently close agreement with those computed using high-fidelity simulations. Most significantly, when the optimal well settings obtained using the TPWL procedure are applied in high-fidelity models, the resulting NPVs are within approximately 0.5% of the values determined using the high-fidelity simulations. Our overall conclusion is that the TPWL representation may be quite useful in production-optimization problems.
Bioorganic chemistry. A natural reunion of the physical and life sciences.

Organic substances were conceived as those found in living organisms. Although the definition was soon broadened to include all carbon-containing compounds, naturally occurring molecules have always held a special fascination for organic chemists. From these beginnings, molecules from nature were indespensible tools as generations of organic chemists developed new techniques for determining structures, analyzed the mechanisms of reactions, explored the effects conformation and stereochemistry on reactions, and found challenging new targets to synthesize. Only recently have organic chemists harnessed the powerful techniques of organic chemistry to study the functions of organic molecules in their biological hosts, the enzymes that synthesize molecules and the complex processes that occur in a cell. In this Perspective, I present a personal account of my entree into bioorganic chemistry as a physical organic chemist and subsequent work to understand the chemical mechanisms of enzyme-catalyzed reactions, to ...
Shaping Proto-Planetary and Young Planetary Nebulae with Collimated Fast Winds

Using two-dimensional hydrodynamical simulations, we investigate the interaction of a collimated fast wind (CFW) interacting with a spherical asymptotic giant branch (AGB) wind as the mechanism for shaping proto-planetary nebulae (PPNs) and young planetary nebulae. In particular, we compare our simulations with the observations of an evolved PPN with multiple, highly collimated lobes, CRL 618. We characterize our model CFW by three parameters—opening angle, velocity, and mass-loss rate—and explore the dependence of the properties of the shell on the first two. For given opening angle and velocity, the mass-loss rate is chosen to give a shell velocity of about 150 km s-1 at the tip, similar to that seen in CRL 618. In our simulations, the shell dynamics is found to depend on the velocity of the fast wind: we obtain a momentum-driven shell for a 300 km s-1 fast wind and a ballistic bow shock-driven shell for a 1000 km s-1 fast wind. The shell driven by the collimated fast wind is highly collimated, even though the AGB wind is spherical. Time variations in the velocity of the fast wind produce a series of internal shock pairs interacting with the inner surface of the shell. As a result of radial expansion, the density of the internal shocks decreases with distance. Various emission diagnostics have been derived from our simulations. For a 300 km s-1 fast wind, the optical emission arises from both the shocked AGB wind and shocked fast wind, showing one or two bright bowlike structures at the tip of the lobe. However, for a 1000 km s-1 fast wind, since the shocked fast wind is much hotter, it emits mainly in X-ray emission; the optical emission forms only one bowlike structure at the tip associated with the shocked AGB wind. The position-velocity (PV) diagrams derived from our simulations all show a broad range of velocities at the tip. The detailed PV structure and velocity range at the tip depend on the shell dynamics and the relative contributions of the shocked fast wind and shocked AGB wind. We make a detailed comparison of our simulations to the observations of the relatively isolated northwestern (W1) lobe of CRL 618. We find that a 300 km s-1 collimated fast wind with an opening angle of 10° can readily produce a highly collimated lobe similar to the W1 lobe, including the bowlike emission structure at its tip. However, our models have difficulty producing the bright emission structures seen along the body of the lobe. The [S II] λ6716/λ6730 ratios at the tip of the lobe in all of our simulations are similar to that observed at the tip of the W1 lobe. The optical line ratios indicate a temperature stratification in the tip; for both the simulations and observations, however, the temperatures at the tip of the lobe in our simulations are higher than observed. The position-velocity (PV) diagrams derived from our simulations are all qualitatively consistent with the current observations. The collimated fast wind in CRL 618 is unlikely to be steady and is not radiatively driven.
Influence of type I collagen surface density on fibroblast spreading, motility, and contractility.

We examine the relationships of three variables (projected area, migration speed, and traction force) at various type I collagen surface densities in a population of fibroblasts. We observe that cell area is initially an increasing function of ligand density, but that above a certain transition level, increases in surface collagen cause cell area to decline. The threshold collagen density that separates these two qualitatively different regimes, ;160 molecules/mm 2 , is approximately equal to the cell surface density of integrin molecules. These results suggest a model in which collagen density induces a qualitative transition in the fundamental way that fibroblasts interact with the substrate. At low density, the availability of collagen binding sites is limiting and the cells simply try to flatten as much as possible by pulling on the few available sites as hard as they can. The force per bond under these conditions approaches 100 pN, approximately equal to the force required for rupture of integrin- peptide bonds. In contrast, at high collagen density adhesion, traction force and motility are limited by the availability of free integrins on the cell surface since so many of these receptors are bound to the surface ligand and the force per bond is very low.
An Ontology Of Economic Objects

Economic reality is constituted by economic objects such as goods, commodities, money, value, price, and exchange that, together, give rise to the complex entity known as the market. Each of these categories is governed by exact laws that provide the conditions for settling objectively whether individuals' views about an instance of any category indeed correspond to that category. This paper describes such laws for each category. The aim of this paper is to lay the groundwork for an ontological description of economic reality.
Case-Based Reasoning

Case-based reasoning (CBR) is an artificial intelligence paradigm for reasoning and learning. Case-based reasoning solves new problems by retrieving stored records of prior problem-solving episodes (cases) and adapting their solutions to fit new circumstances. Each processing episode provides a new case that is stored for future reuse, making learning a natural side-effect of the reasoning process. Case-based reasoning is also studied within cognitive science as a model of human reasoning: studies show that people use recollections of prior problems to guide their reasoning in a wide range of tasks, such as programming, mathematical problem solving, diagnosis, decision making, and design.
The homotopy fixed point spectra of profinite Galois extensions

Let E be a k-local profinite G-Galois extension of an E ∞ -ring spectrum A (in the sense of Rognes). We show that E may be regarded as producing a discrete G-spectrum. Also, we prove that if E is a profaithful k-local profinite extension which satisfies certain extra conditions, then the forward direction of Rognes's Galois correspondence extends to the profinite setting. We show that the function spectrum F A ((E hH ) k , (E hK ) k ) is equivalent to the localized homotopy fixed point spectrum ((E||G/H]]) hK ) k , where H and K are closed subgroups of G. Applications to Morava E-theory are given, including showing that the homotopy fixed points defined by Devinatz and Hopkins for closed subgroups of the extended Morava stabilizer group agree with those defined with respect to a continuous action in terms of the derived functor of fixed points.
Rational symplectic field theory for Legendrian knots

We construct a combinatorial invariant of Legendrian knots in standard contact three-space. This invariant, which encodes rational relative Symplectic Field Theory and extends contact homology, counts holomorphic disks with an arbitrary number of positive punctures. The construction uses ideas from string topology.
A programmable clock generator that uses noise shaping and its application in switched-capacitor filters

A programmable digital clock generator that produces a wide range of clock frequencies with fine resolution is described. The clock generator consists of a noise-shaping control loop and a number-controlled oscillator. The generated clock has a time-varying period. When this clock is used as the sampling clock in a switched-capacitor filter (SCF) to set its frequency response, the time-varying period causes nonuniform sampling, which is acceptable under certain conditions that are described. Measured performance of a 2-/spl mu/m CMOS implementation of the clock generator is presented. Also, measured data for the clock generator driving two SCF's are reported. >
Paying for Progress: Conditional Grants and the Desegregation of Southern Schools

This paper examines how a large conditional grants program influenced school desegregation in the American South. Exploiting newly collected archival data and quasi-experimental variation in potential per-pupil federal grants, we show that school districts with more at risk in 1966 were more likely to desegregate just enough to receive their funds. Although the program did not raise the exposure of blacks to whites like later court orders, districts with larger grants at risk in 1966 were less likely to be under court order through 1970, suggesting that tying federal funds to nondiscrimination reduced the burden of desegregation on federal courts. I. INTRODUCTION Because the U.S. Constitution reserves powers not explicitly delegated to the federal government to the states, conditional grants are key levers for federal policymakers seeking to affect a broad range of state and local policies. States must implement federally approved speed limits and drinking ages to receive highway funding; universities must provide gender parity in athletic offerings to receive research funding; and states can lose funding if they do not comply with the Clean Air Act. More recently, states and school districts have risked losing federal grants for failure to comply with the accountability requirements of the No Child Left Behind Act. In this paper, we examine whether the threat
Propiconazole Inhibits Steroidogenesis and Reproduction in the Fathead Minnow (Pimephales promelas)

Conazoles are designed to inhibit cytochrome P450 (CYP) 14α-demethylase, an enzyme key to fungal cell wall formation. In vertebrates, conazoles may inhibit other CYPs, potentially disrupting processes like sex steroid synthesis. Propiconazole is a current-use pesticide that is among the first chemicals being tested in the U.S. Environmental Protection Agency endocrine disruptor screening program. Fathead minnows (Pimephales promelas) were exposed to 0, 5, 50, 500, or 1000 µg propiconazole/l in a 21-day study that evaluated apical reproductive endpoints (fecundity, fertility, hatch); measures of endocrine function and steroid synthesis, such as cholesterol, vitellogenin (VTG), and sex steroid (testosterone [T], 17β-estradiol [E2]) concentrations in the plasma; and changes in gonadal expression of steroidogenic genes. Plasma E2 and VTG concentrations in females were reduced by exposure to propiconazole, and egg production was decreased in the 500 and 1000 µg/l treatment groups. These in vivo effects coincided with inhibition of E2 synthesis by ovary explants exposed to propiconazole in vitro. We also observed a compensatory response in females exposed to propiconazole, manifested as increased gonad weight and upregulation of genes coding for key steriodogenic proteins, including CYP19 (aromatase), CYP17 (hydroxylase/ lyase), CYP11A (cholesterol side-chain-cleavage), and steroidogenic acute regulatory protein. Other than an increase in relative testis weight, effects on endocrine function in males were less pronounced than in females. This study provides important data relative to the potential endocrine activity of propiconazole in fish and, more generally, to the further delineation of pathways for the reproductive effects of steroid synthesis inhibitors in fish.
Constructive Algorithms for Discrepancy Minimization

Given a set system $(V,\mathcal{S})$, $V=\{1,\ldots,n\}$ and $\mathcal{S}=\{S_1,\ldots,S_m\}$, the minimum discrepancy problem is to find a 2-coloring $\mathcal{X}:V \right arrow \{-1,+1\}$, such that each set is colored as evenly as possible, i.e. find $\mathcal{X}$ to minimize $\max_{j \in [m]} \left|\sum_{i \in S_j} \mathcal{X}(i)\right|$. In this paper we give the first polynomial time algorithms for discrepancy minimization that achieve bounds similar to those known existentially using the so-called Entropy Method. We also give a first approximation-like result for discrepancy. Specifically we give efficient randomized algorithms to: 1. Construct an $O(n^{1/2})$ discrepancy coloring for general sets systems when $m=O(n)$, matching the celebrated result of Spencer up to $O(1)$ factors. More generally, for $m\geq n$, we obtain a discrepancy of $O(n^{1/2} \log (2m/n))$. 2. Construct a coloring with discrepancy $O(t^{1/2} \log n)$, if each element lies in at most $t$ sets. This matches the (non-constructive) result of Srinivasan. 3. Construct a coloring with discrepancy $O( \lambda\log (nm))$, where $\lambda$ is the hereditary discrepancy of the set system. The main idea in our algorithms is to produce a coloring over time by letting the color of the elements perform a random walk (with tiny increments) starting from 0 until they reach $\pm 1$. At each step the random hops for various elements are correlated by a solution to a semi definite program, where this program is determined by the current state and the entropy method.
Particulate Matter Emissions from a Direct Injection Spark Ignition Engine under Cold Fast Idle Conditions for Ethanol-Gasoline Blends

The engine out particular matter number (PN) distributions at engine coolant temperature (ECT) of 0 o C to 40 o C for ethanol/ gasoline blends (E0 to E85) have been measured for a direct-injection spark ignition engine under cold fast idle condition. For E10 to E85, PN increases modestly when the ECT is lowered. The distributions, however, are insensitive to the ethanol content of the fuel. The PN for E0 is substantially higher than the gasohol fuels at ECT below 20 o C. The total PN values (obtained from integrating the PN distribution from 15 to 350 nm) are approximately the same for all fuels (E0 to E85) when ECT is above 20 o C. When ECT is
Dense Perovskite, La1-xA′xFe1-yCoyO3-δ (A′= Ba, Sr, Ca), Membrane Synthesis, Applications, and Characterization

La1-xA′xFe0.8Co0.2O3-δ (A′= Ca, Sr, Ba) perovskite powders were synthesized to attain the desired properties of high O2 flux and stability under reducing conditions. Steady-state oxygen permeation rates for La1-xA′xFe0.8-Co0.2O3-δ perovskite membranes in nonreacting experiments with air on one side and helium on the other side of the membrane were in the order A′x= Ba0.8 > Ba0.6 > Ca0.6 > Sr0.6. Partial oxidation of methane to syngas (CO + H2) was performed in a dense La0.2Ba0.8Fe0.8Co0.2O3-δ membrane reactor at 850°C in which oxygen was separated from air and simultaneously fed into the methane stream. The reducing atmosphere affected the membrane reaction-side surface while barium enrichment occurred on the air-side surface. Oxygen continuously transported from the air side appeared to stabilize the membrane interior, and the reactor was operated for up to 850 h.