cssi/SciSciGPT-SciSciNet huggingface dataset:
Analysis of climate policy targets under uncertainty

Although policymaking in response to the climate change threat is essentially a challenge of risk management, most studies of the relation of emissions targets to desired climate outcomes are either deterministic or subject to a limited representation of the underlying uncertainties. Monte Carlo simulation, applied to the MIT Integrated Global System Model (an integrated economic and earth system model of intermediate complexity), is used to analyze the uncertain outcomes that flow from a set of century-scale emissions paths developed originally for a study by the U.S. Climate Change Science Program. The resulting uncertainty in temperature change and other impacts under these targets is used to illustrate three insights not obtainable from deterministic analyses: that the reduction of extreme temperature changes under emissions constraints is greater than the reduction in the median reduction; that the incremental gain from tighter constraints is not linear and depends on the target to be avoided; and that comparing median results across models can greatly understate the uncertainty in any single model.
On the stereoselective bicyclization of aminodienes catalyzed by chelating diamide complexes of the group 3 metals. A direct comparison of Sc(III) and Y(III) bis(amide)s with an application to the synthesis of alkaloid 195F

Highly diastereoselective bicyclizations of aminodienes catalyzed by chelating diamide complexes of Sc(III) and Y(III) that lead to pyrrolizidines and indolizidines are described. This bis(annulation) procedure has been utilized in a concise synthesis of the pyrrolizidine alkaloid 195F.
The Influence of Assortment Structure on Perceived Variety and Consumption Quantities

Increasing the actual variety of an assortment has been shown previously to increase the quantity consumed. We show, however, that consumption quantities are also influenced by the perceived variety of an assortment. In combination, six lab and field studies show that the structure of an assortment (e.g., organization and symmetry or entropy) moderates the effect of actual variety on perceived variety. We further show that it is perceived variety that in turn influences consumption quantities through anticipated consumption utility. Making salient other consumption rules, such as size of the assortment, moderates this effect. These findings are of immediate relevance to interdisciplinary researchers and to consumers and health practitioners who wish to better control food consumption.
Model Checking Transactional Memory with Spin

We used the Spin model checker to show that Intel's implementation of software transactional memory is correct. Transactional memory makes it possible to write properly-synchronized multi-threaded programs without the explicit use of locks. We describe our model of Intel's implementation, our experience with Spin, what we have shown, and what obstacles remain to showing more.
Ultimate Strain Measurement of Micromachined Membranes Using a Potentiometric Technique

A potentiometric method for the measurement of ultimate strain of thin films is presented. In this method, an electric potential is applied between two electrodes located one on each side of the thin film under investigation. The electrodes are immersed in an electrolytic solution. The thin film acts as an electrical current barrier. To determine the ultimate strain, a controlled load is applied to the film. Cracking of the film causes a sharp rise in the current from an initial small leakage value. The applied load at the onset of cracking is used to calculate the ultimate strain. we have previously demonstrated the feasibility of the method for thin silicon nitride films deposited on aluminum strips. The method is very sensitive and can detect cracks too small to be observed with a microscope. We discuss extension of the method to the measurement of the ultimate strain of micromachined membranes. The load is applied by pressurizing one side of the membrane. Micromachined structures are used to determine residual stresses.
The effective csr forces for an energy-chirped bunch under magnetic compression

Following our earlier formulation of the coherent synchrotron radiation (CSR) effect on bunch dynamics in magnetic bends, here we investigate the behavior of the effective CSR forces for an energy-chirped Gaussian bunch in the bending plane around full compression, with special care being taken in the incorporation of the retardation relation. Our results show clearly a delayed response of the CSR forces to the compression or lengthening of the bunch length. In addition, around full compression, our results reveal sensitivity of the effective CSR forces on the particles' transverse position, as a consequence of the geometry of particle interaction and retardation in this regime. These results can serve as benchmarks to the numerical simulation of the CSR effects.
The New Economics of Inequality and Redistribution

Economists warn that policies to level the economic playing field come with a hefty price tag. But this so-called 'equality-efficiency trade-off' has proven difficult to document. The data suggest, instead, that the extraordinary levels of economic inequality now experienced in many economies are detrimental to the economy. Moreover, recent economic experiments and other evidence confirm that most citizens are committed to fairness and are willing to sacrifice to help those less fortunate than themselves. Incorporating the latest results from behavioral economics and the new microeconomics of credit and labor markets, Bowles shows that escalating economic disparity is not the unavoidable price of progress. Rather it is policy choice - often a very costly one. Here drawing on his experience both as a policy advisor and an academic economist, he offers an alternative direction, a novel and optimistic account of a more just and better working economy.
Computer manipulation of digitized pictures

To an increasing degree, equipment is available which is capable of converting photographic information into machine readable form or converting computer files into a visual image more or less resembling a half-tone picture, thus rendering photographic and other pictorial information available as data for processing by digital computers. Three major directions of effort have ensued. Necessary utility routines have been developed for managing I/O, file manipulation, and the implementation of languages to facilitate programming effort; analytical work toward character and pattern recognition, and toward parametric characterization of pictures has led to algorithms for accomplishing various sorts of mensuration and analysis; and, finally, algorithms have begun to emerge which are designed to change the appearance of a picture by modifying the file which represents it. A brief list of references to this work is given at the end of the paper, including an excellent review of the field by Lipkin and Rosenfeld.
Econometric-Process Models for Integrated Assessment of Agricultural Production Systems

This article develops the conceptual and empirical basis for a class of empirical economic production models that can be linked to site-specific biophysical models for use in integrated assessment research. Site-specific data are used to estimate econometric production models, and these data and models are then incorporated into a simulation model that represents the decision-making process of the farmer as a sequence of discrete and continuous land-use and input-use decisions. An econometric-process model of the dryland grain production system of the Northern Plains demonstrates the capabilities of this type of model to simulate decision making both within and outside the range of observed data. Copyright 2001, Oxford University Press.
Status and performance of the CDF Run II silicon detector

We report our experience commissioning and operating the CDF Run II silicon detector during the first three years of Run II. The performance of the system and its impact on physics analysis are reviewed. As the luminosity delivered by the Tevatron increases, measurable effects of radiation damage have been observed. Studies of charge collection and noise versus applied bias voltage at several different integrated luminosities are presented. These results and their impact on the expected lifetime of the detector are discussed.
The effects of speech production and speech comprehension on simulated driving performance

We performed two experiments comparing the effects of speech production and speech comprehension on simulated driving performance. In both experiments, participants completed a speech task and a simulated driving task under single- and dual-task conditions, with language materials matched for linguistic complexity. In Experiment 1, concurrent production and comprehension resulted in more variable velocity compared to driving alone. Experiment 2 replicated these effects in a more difficult simulated driving environment, with participants showing larger and more variable headway times when speaking or listening while driving than when just driving. In both experiments, concurrent production yielded better control of lane position relative to single-task performance; concurrent comprehension had little impact on control of lane position. On all other measures, production and comprehension had very similar effects on driving. The results show, in line with previous work, that there are detrimental consequences for driving of concurrent language use. Our findings imply that these detrimental consequences may be roughly the same whether drivers are producing speech or comprehending it.
Video coding for streaming media delivery on the Internet

We provide an overview of an architecture of today's Internet streaming media delivery networks and describe various problems that such systems pose with regard to video coding. We demonstrate that based on the distribution model (live or on-demand), the type of the network delivery mechanism (unicast versus multicast), and optimization criteria associated with particular segments of the network (e.g., minimization of distortion for a given connection rate, minimization of traffic in the dedicated delivery network, etc.), it is possible to identify several models of communication that may require different treatment from both source and channel coding perspectives. We explain how some of these problems can be addressed using a conventional framework of temporal motion-compensated, transform-based video compression algorithm, supported by appropriate channel-adaptation mechanisms in client and server components of a streaming media system. Most of these techniques have already been implemented in RealNetworks(R) RealSystem(R) 8 and its RealVideo(R) 8 codec, which we use throughout the paper to illustrate our results.
Decentralized Trading with Private Information

The paper studies how asset prices are determined in a decentralized market with asymmetric information about asset values. We consider an economy in which a large number of agents trade two assets in bilateral meetings. A fraction of the agents has private information about the asset values. We show that, over time, uninformed agents can elicit information from their trading partners by making small offers. This form of experimentation allows the uninformed agents to acquire information as long as there are potential gains from trade in the economy. As a consequence, the economy converges to a Pareto efficient allocation.
Sociotropes, Systematic Bias, and Political Failure: Reflections on the Survey of Americans and Economists on the Economy

Objectives. Economic models of politics typically make two assumptions about voters: First, their motives are egocentric, not sociotropic; second, their beliefs are rational, not subject to systematic bias. Political scientists have presented strong evidence against the first assumption (Mansbridge, 1990), but have become increasingly willing to accept the second. (Page and Shapiro, 1992; Marcus and Hanson, 1993) This article tests these two assumptions, then explores the tests’ broader implications. Methods. I use the Survey of Americans and Economists on the Economy to test for egocentricity of motivation and rationality of belief. Results. Both standard assumptions fail for the case where the economic approach would seemingly be most relevant: economic beliefs. Conclusions. This is not necessarily cause for greater optimism about the efficiency of democracy: sociotropic voters with biased economic beliefs are more likely to produce severe political failures than are selfish voters with rational expectations.
Hadamard transform time-of-flight mass spectrometry: more signal, more of the time.

Hadamard transform time-of-flight mass spectrometry (HT-TOF MS) is a type of mass analysis that was developed to couple continuous ion sources to the inherently pulsed nature of time-of-flight measurements. Unlike conventional TOF MS, the Hadamard transform method offers a duty cycle of 50 %, with the possibility of extending it to 100 %. Because it is a multiplexing technique, the attainable signal-to-noise ratio (SNR) is also significantly higher than that of conventional TOF MS. This review covers the basic principles behind HT TOF MS. We illustrate, through examples, the source of the high-duty cycle and the increase in SNR. These features translate to a mass spectral storage rate that is the fastest among similar instruments, which enables its use as a detector for high-speed separations.
Conceptual Analysis of Garden-Path Sentences

By integrating syntactic and semantic processing, our parser (LAZY) is able to deterministically parse sentences which syntactically appear to be garden path sentences although native speakers do not need conscious reanalysis to understand them. LAZY comprises an extension to conceptual analysis which yields an explicit representation of syntactic information and a flexible interaction between semantic and syntactic knowledge.
The scalable reasoning system: lightweight visualization for distributed analytics

A central challenge in visual analytics is the creation of accessible, widely distributable analysis applications that bring the benefits of visual discovery to as broad a user base as possible. Moreover, to support the role of visualization in the knowledge creation process, it is advantageous to allow users to describe the reasoning strategies they employ while interacting with analytic environments. We introduce an application suite called the scalable reasoning system (SRS), which provides web-based and mobile interfaces for visual analysis. The service-oriented analytic framework that underlies SRS provides a platform for deploying pervasive visual analytic environments across an enterprise. SRS represents a 'lightweight' approach to visual analytics whereby thin client analytic applications can be rapidly deployed in a platform-agnostic fashion. Client applications support multiple coordinated views while giving analysts the ability to record evidence, assumptions, hypotheses and other reasoning artifacts. We describe the capabilities of SRS in the context of a real-world deployment at a regional law enforcement organization.
Automatic tracking of SPAMM grid and the estimation of deformation parameters from cardiac MR images

Presents a new approach for the automatic tracking of SPAMM (Spatial Modulation of Magnetization) grid in cardiac MR images and consequent estimation of deformation parameters. The tracking is utilized to extract grid points from MR images and to establish correspondences between grid points in images taken at consecutive frames. These correspondences are used with a thin plate spline model to establish a mapping from one image to the next. This mapping is then used for motion and deformation estimation. Spatio-temporal tracking of SPAMM grid is achieved by using snakes/spl minus/active contour models with an associated energy functional. The authors present a minimizing strategy which is suitable for tracking the SPAMM grid. By continuously minimizing their energy functionals, the snakes lock on to and follow the in-slice motion and deformation of the SPAMM grid. The proposed algorithm was tested with excellent results on 123 images (three data sets each a multiple slice 2D, 16 phase Cine study, three data sets each a multiple slice 2D, 13 phase Cine study and three data sets each a multiple slice 2D, 12 phase Cine study). >
A modified lightly doped drain structure for VLSI MOSFET's

A new n-MOS LDD-like device structure (the J-MOS transistor) is proposed. Its design, simulation, and fabrication are studied in this paper, n-channel MOSFET's with L eff below 2 µm suffer from high-field effects that must be overcome to secure reliable 5-V operation. LDD structures alleviate these effects, but their reliability is better than that of conventional MOSFET's only if the n-regions have a peak doping density above 1 × 1018cm-3. To overcome this limitation and to allow constant voltage scaling for devices into the submicrometer regime, the J-MOS structure uses a series drain JFET to drop part of the supply voltage. Both 2-D device simulations and experimental results are presented to demonstrate the operation of this device and its potential for applications requiring reliable submicrometer device operation under maximum supply voltage. The major experimental findings are that the J-MOS structure can sustain 5-V operation even for submicrometer effective channel lengths. As has been the case with all LDD-like structures, improved device reliability has been achieved at the expense of some performance. However, the advantages of keeping 5-V operation in micrometer-sized devices may outweigh this performance loss.
Chiral Synthesis of Functionalized Tetrahydropyridines: γ-Aminobutyric Acid Uptake Inhibitor Analogues

A convenient preparation of functionalized chiral tetrahydropyridine-3-carboxylates from nitriles in 68−90% enantiomeric excess (ee) via allylboration, followed by a conjugate addition−elimination and ring-closing metathesis, has been developed. Thus, the treatment of the acetate derived from vinylalumination of formaldehyde by use of [α-(ethoxycarbonyl)vinyl]diisobutylaluminum with chiral β-substituted and β-unsubstituted homoallylic amines, prepared in >98% diastereomeric excess (de) and 68−90% ee via allylboration of the corresponding N-aluminoimines, furnished functionalized aminodienes, which underwent ring-closing metathesis to provide chiral C5−C6 disubstituted tetrahydropyridine-3-carboxylates. This methodology has been applied for the synthesis of a chiral C6-substituted tetrahydropyridine with known GABA-inhibiting properties at low concentrations.
Massive Star Clusters in Ongoing Galaxy Interactions: Clues to Cluster Formation*

We present HST WFPC2 observations, supplemented by ground-based Hα data, of the star-cluster populations in two pairs of interacting galaxies selected for being in very different kinds of encounters seen at different stages. Dynamical information and n-body simulations provide the details of encounter geometry, mass ratio, and timing. In NGC 5752/4 we are seeing a weak encounter, well past closest approach, after about 2.5 × 108 yr. The large spiral NGC 5754 has a normal population of disk clusters, while the fainter companion NGC 5752 exhibits a rich population of luminous clusters with a flatter luminosity function. The strong, ongoing encounter in NGC 6621/2, seen about 1.0 × 108 yr past closest approach between roughly equal-mass galaxies, has produced an extensive population of luminous clusters, particularly young and luminous in a small region between the two nuclei. This region is dynamically interesting, with such a strong perturbation in the velocity field that the rotation curve reverses sign. From these results, in comparison with other strongly interacting systems discussed in the literature, cluster formation requires a threshold level of perturbation, with stage of the interaction a less important factor. The location of the most active star formation in NGC 6621/2 draws attention to a possible role for the Toomre stability threshold in shaping star formation in interacting galaxies. The rich cluster populations in NGC 5752 and NGC 6621 show that direct contact between gas-rich galaxy disks is not a requirement to form luminous clusters and that they can be triggered by processes happening within a single galaxy disk (albeit triggered by external perturbations).
Software Quality Classification Modeling Using the SPRINT Decision Tree Algorithm

Predicting the quality of system modules prior to software testing and operations can benefit the software development team. Such a timely reliability estimation can be used to direct cost-effective quality improvement efforts to the high-risk modules. Tree-based software quality classification models based on software metrics are used to predict whether a software module is fault-prone or not fault-prone. They are white box quality estimation models with good accuracy, and are simple and easy to interpret. An in-depth study of calibrating classification trees for software quality estimation using the SPRINT decision tree algorithm is presented. Many classification algorithms have memory limitations including the requirement that datasets be memory resident. SPRINT removes all of these limitations and provides a fast and scalable analysis. It is an extension of a commonly used decision tree algorithm, CART, and provides a unique tree pruning technique based on the Minimum Description Length (MDL) principle. Combining the MDL pruning technique and the modified classification algorithm, SPRINT yields classification trees with useful accuracy. The case study used consists of software metrics collected from a very large telecommunications system. It is observed that classification trees built by SPRINT are more balanced and demonstrate better stability than those built by CART.
A Methodology for the Optimal Configuration of TCP Traffic in Network Simulations under Link Load Constraints

Given that more than 90% of the Internet load is carried by TCP, most network simulation studies use TCP flows to generate the background traffic. A basic, but unresolved, question, however, is the following: how can one decide how many TCP flows to simulate from one network node to another? Simulating too many flows on a link can cause an unrealistically high loss rate on that link, while simulating too few flows can result in undesirably light load conditions. Similarly, to simulate realistic network conditions, one has to carefully control the load distribution on various network links (e.g., edge vs. core links), as well as the hop count (path length) of the simulated TCP flows. Previous simulation studies have dealt with these issues in a trial-and-error manner, experimenting with several traffic configurations until a realistic distribution of link load and loss rate is achieved. In this article, the authors present a methodology that determines the number of TCP flows that should be simulated between each pair of nodes in a network based on the network topology, a specification of the utilization and loss rate for certain links, and an average number of hops for the TCP flows. The proposed methodology is based on a linear program formulation that, while meeting the utilization and loss rate specifications, minimizes the number of required TCP flows. This optimization criterion minimizes the memory requirement of the simulation. The evaluations show that the proposed methodology can closely approximate the specified link conditions in terms of utilization and loss rate. The authors also analyze the largest approximation errors and reveal their causes.
Do oil price increases cause higher food prices

US retail food price increases in recent years may seem large in nominal terms, but after adjusting for inflation have been quite modest even after the change in US biofuel policies in 2006. In contrast, increases in the real prices of corn, soybeans, wheat and rice received by US farmers have been more substantial and can be linked in part to increases in the real price of oil. That link, however, appears largely driven by common macroeconomic determinants of the prices of oil and of agricultural commodities rather than the pass-through from higher oil prices. We show that there is no evidence that corn ethanol mandates have created a tight link between oil and agricultural markets. Moreover, increases in agricultural commodity prices have contributed little to US retail food price increases, because of the small cost share of agricultural products in food prices. In short, there is no evidence that oil price shocks have been associated with more than a negligible increase in US retail food prices in recent years. Nor is there evidence for the prevailing wisdom that oil-price driven increases in the cost of food processing, packaging, transportation and distribution have been responsible for higher retail food prices. Similar results hold for other industrialized countries. There is reason, however, to expect food commodity prices to be more tightly linked to retail food prices in developing countries. — Christiane Baumeister and Lutz Kilian
Inferring Rankings Using Constrained Sensing

We consider the problem of recovering a function over the space of permutations (or, the symmetric group) over n elements from given partial information; the partial information we consider is related to the group theoretic Fourier Transform of the function. This problem naturally arises in several settings such as ranked elections, multi-object tracking, ranking systems, and recommendation systems. Inspired by the work of Donoho and Stark in the context of discrete-time functions, we focus on non-negative functions with a sparse support (support size <;<; domain size). Our recovery method is based on finding the sparsest solution (through l0 optimization) that is consistent with the available information. As the main result, we derive sufficient conditions for functions that can be recovered exactly from partial information through l0 optimization. Under a natural random model for the generation of functions, we quantify the recoverability conditions by deriving bounds on the sparsity (support size) for which the function satisfies the sufficient conditions with a high probability as n → ∞. l0 optimization is computationally hard. Therefore, the popular compressive sensing literature considers solving the convex relaxation, l1 optimization, to find the sparsest solution. However, we show that l1 optimization fails to recover a function (even with constant sparsity) generated using the random model with a high probability as n → ∞. In order to overcome this problem, we propose a novel iterative algorithm for the recovery of functions that satisfy the sufficient conditions. Finally, using an Information Theoretic framework, we study necessary conditions for exact recovery to be possible.
Analytical solution of a model radiative equation arising in atmospheric sounding.

Abstract The problem of inferring the thermal structure of the atmosphere by means of remote sensing is considered within the context of a model transmission function of the form τ(v, p) = exp [−p/ω(v)]. An analytical solution is derived for a large class of outgoing radiances. The model seems capable of yielding a tropopause. It also yields a formula for the surface temperature.
On Kalman's procedure for the computation of the controllable/observable canonical form

An example is given in which the algorithm given in Kalman1 to compute the joint controllability-observability decomposition fails. In §7 of Kalman [1], there is described a procedure to compute the joint controllability-observability decomposition of a linear time invariant dynamic System x= Fx + Gu (1) y=Hx where 1 follow the notation in Kalman[1].
Subsonic and Transonic Potential Flow over Helicopter Rotor Blades

Compressible potential flows over nonlifting, hovering helicopter blades are described by suitable linear and nonlinear equations of motion for subsonic and transonic cases, respectively. Analytical and numerical results are presented for the linearized subsonic three-dimensional flow in the tip region. When the tip Mach number is transonic, the flowfield is calculated using a computational method that is a formal extension to three dimensions of recently developed nonlinear two-dimensional relaxation schemes. Calculations are presented for rectangular blades with 6% thick biconvex sections. Calculations show the relative importance of tip Mach number and aspect ratio on the growth and extent of shock waves in the tip region, and indicate a significant reduction in shock strength with decreasing aspect ratio. ELICOPTER rotor blades that can operate at high tip Mach numbers without the penalties usually associated with super-critical flow would permit high-forward speeds at relatively low-advance ratios. As the advance ratio decreases, the portion of the retreating blade that is stalled would be diminished, the portion of the retreating blade that is unstalled could operate at smaller angles of attack, and the advancing blade could generate lift without also generating an excessive rolling moment. Vibratory loads would be diminished, and severe unsteady pitching moments on the lifting portion of the retreating blade would decrease if that portion could usefully operate at higher tip speeds and smaller angles of attack. The design of rotor blade geometries that can support a transonic flowfield that is nearly shock-free requires a method for computing the detailed pressure distribution on the blade for a specified rotor geometry and advance ratio. However, the unsteady aerodynamic environment of a lifting rotor that is operating at or near the critical Mach number is extremely complicated. It is easy to appreciate the difficulty of describing such flowfields when one recalls that we do not yet have an adequate model for describing the details of the flow about a lifting, hovering rotor operating in an essentially incompressible flow. Our purpose here is therefore to focus on a portion of the high-speed rotor problem that is sufficiently limited to allow for some analytical and numerical treatment, but which retains important linear and nonlinear features of the flow. We consider a two-bladed nonlifting and hovering rotor operating in the range of tip Mach numbers where compressibility effects are important. The pressure distribution near the rotor tip is studied. In this region, the flowfield is fully three-dimensional, and blade element (strip) theory is in no sense a reasonable approximation to the rotor aerodynamics. It is assumed that the flow is inviscid. The flow is steady relative to a coordinate system attached to the blades. Analytical and numerical results presented here are based on suitable approximations to the full three-dimensional potential equation for compressible flow. When the tip Mach number is subcritical, the potential equation is the usual acoustic
Modern Developments in Flow Visualization

Revue de differentes methodes de visualisation: techniques de traceurs, thermographie infrarouge, interferometrie laser et holographie, tomographie, photographie a grande vitesse videographie a grande vitesse, traitements optique et digital des images. Application en aerodynamique
On the number of matrices and a random matrix with prescribed row and column sums and 0–1 entries☆

Abstract We consider the set Σ ( R , C ) of all m × n matrices having 0–1 entries and prescribed row sums R = ( r 1 , … , r m ) and column sums C = ( c 1 , … , c n ) . We prove an asymptotic estimate for the cardinality | Σ ( R , C ) | via the solution to a convex optimization problem. We show that if Σ ( R , C ) is sufficiently large, then a random matrix D ∈ Σ ( R , C ) sampled from the uniform probability measure in Σ ( R , C ) with high probability is close to a particular matrix Z = Z ( R , C ) that maximizes the sum of entropies of entries among all matrices with row sums R, column sums C and entries between 0 and 1. Similar results are obtained for 0–1 matrices with prescribed row and column sums and assigned zeros in some positions.
Calogero-Moser and Toda systems for twisted and untwisted affine Lie algebras

The elliptic Calogero-Moser Hamiltonian and Lax pair associated with a general simple Lie algebra G are shown to scale to the (affine) Toda Hamiltonian and Lax pair. The limit consists in taking the elliptic modulus τ and the Calogero-Moser couplings m to infinity, while keeping fixed the combination M = m eiδθτ for some exponent δ. Critical scaling limits arise when 1/δ equals the Coxeter number or the dual Coxeter number for the untwisted and twisted Calogero-Moser systems respectively; the limit consists then of the Toda system for the affine Lie algebras G(1) and (G(1))V. The limits of the untwisted or twisted Calogero-Moser system, for δ less than these critical values, but non-zero, consists of the ordinary Toda system, while for δ = 0, it consists of the trigonometric Calogero-Moser systems for the algebras G and GV respectively.
Finite-State Analysis of Security Protocols

Several approaches have been developed for analyzing security protocols. These include specialized logics that formalize notions such as secrecy and belief, special-purpose automated tools for cryptographic protocol analysis, and methods that apply general theoremproving or model-checking tools to security protocols. This short document, written to accompany the author's invited lecture, provide background information and references on finite-state methods that use standard model-checking tools.
Analysis and Identification of Subsynchronous Vibration for a High Pressure Parallel Flow Centrifugal Compressor

The evaluation of turbomachinery designs prior to actual hardware test and field installation is now the rule rather than the exception for rotating machinery manufacturers. This requires the verification of the current state of the art analytical techniques for rotor-bearing-seal dynamics by development testing and/or controlled test stand or field vibration studies. This paper presents the summary of a complete analytical design evaluation of an existing parallel flow compressor and reviews a recent field vibration problem that manifested itself as a subsynchronous vibration that tracked at approximately 2/3 of compressor speed. The comparison of predicted and observed peak response speeds, frequency spectrum content, and the performance of the bearing-seal systems are presented as the events of the field problem are reviewed. Conclusions and recommendations are made based upon the results of this design review.
Brownian motors: noisy transport far from equilibrium

Abstract Transport phenomena in spatially periodic systems far from thermal equilibrium are considered. The main emphasis is put on directed transport in so-called Brownian motors (ratchets), i.e. a dissipative dynamics in the presence of thermal noise and some prototypical perturbation that drives the system out of equilibrium without introducing a priori an obvious bias into one or the other direction of motion. Symmetry conditions for the appearance (or not) of directed current, its inversion upon variation of certain parameters, and quantitative theoretical predictions for specific models are reviewed as well as a wide variety of experimental realizations and biological applications, especially the modeling of molecular motors. Extensions include quantum mechanical and collective effects, Hamiltonian ratchets, the influence of spatial disorder, and diffusive transport.
Calculation of processes involving many particles at the kinematical threshold.

A diagrammatic technique is derived for calculating processes involving the production of large numbers of particles. As an example, the amplitude of three particles scattering into [ital n] particles at the kinematical threshold in [lambda][phi][sup 4] theory is calculated. From the 3[r arrow][ital n] amplitude, it is seen that the one-loop amplitude for 2[r arrow][ital n] processes is suppressed by a factor of 1/[ital n].
Faster algorithms for privately releasing marginals

We study the problem of releasing k-way marginals of a database D∈({0, 1}d)n, while preserving differential privacy. The answer to a k-way marginal query is the fraction of D's records x∈{0, 1}d with a given value in each of a given set of up to k columns. Marginal queries enable a rich class of statistical analyses of a dataset, and designing efficient algorithms for privately releasing marginal queries has been identified as an important open problem in private data analysis (cf. Barak et. al., PODS '07). We give an algorithm that runs in time $d^{O(\sqrt{k})}$ and releases a private summary capable of answering any k-way marginal query with at most ±.01 error on every query as long as $n \geq d^{O(\sqrt{k})}$. To our knowledge, ours is the first algorithm capable of privately releasing marginal queries with non-trivial worst-case accuracy guarantees in time substantially smaller than the number of k-way marginal queries, which is dΘ(k) (for k≪d).
Racial Diversity and Macroeconomic Productivity across US States and Cities

Sparber C. Racial diversity and macroeconomic productivity across US states and cities, Regional Studies. Racial diversity in the USA continues to rise. Past analyses have argued that diversity can have both positive and negative consequences. The overall macroeconomic effects of diversity within the USA require further examination. This paper exploits variation across US regions from 1980 to 2000 to determine whether racial heterogeneity creates gains or losses for states and cities. Fixed-effects analysis indicates that diversity enhances the productivity of cities. Evidence at the state level is more ambiguous, as significant results only appear in random-effects specifications. Sparber C. La diversite ethnique et la productivite macroeconomique a travers les etats et les grandes villes aux E-U, Regional Studies. Aux Etats-Unis, la diversite ethnique est toujours a la hausse. Des etudes anterieures ont cherche a affirmer que les consequences de la diversite ethnique peuvent s'averer a la fois positives...
Building polyfunctional piperidines: a stereoselective strategy of a three-component Mannich reaction inspired by biosynthesis and applications in the synthesis of natural alkaloids (+)-241D; (−)-241D; isosolenopsin A and (−)-epimyrtine

A general method to assemble multi-substituted chiral piperidines was developed, inspired by the biosynthesis of piperidine natural products. In biosynthesis, Δ1-piperideine 4 plays a key role as a common intermediate giving rise to a variety of piperidine-based natural alkaloids. Nature uses L-lysine as a building block, enzymatically transforming it into a δ-amino carbonyl intermediate 3 as the precursor to cyclize into Δ1-piperideine 4. We envisioned that such a process could be accomplished by a vinylogous type Mannich reaction if a functionalized dienolate was employed. A stereoselective three-component vinylogous Mannich-type reaction (VMR) of 1,3-bis-trimethylsily enol ether 7 was therefore investigated and was found to give cyclized chiral dihydropyridinone compound 9 as an adduct. Like Δ1-piperideine in biosynthesis, the chiral 2,3-dihydropyridinone compound 9 from VMR is a versatile intermediate for building a variety of new chiral piperidine compounds. The method was showcased by concise two-step approaches in the synthesis of the bioactive natural alkaloids (+)-241D; (−)-241D and isosolenopsin A. Furthermore, when properly functionalized substrate aldehyde 24 was employed, the corresponding dihydropyridinone adduct 25 cyclized to form a second piperidine ring, leading to a chiral polyfunctional quinolizidine enaminone 27. This versatile intermediate was used to prepare a variety of new chiral quinolizidine compounds, including natural alkaloid (−)-epimyrtine.
Truth-Telling reservations

We present a mechanism for reservations of bursty resources that is both truthful and robust. It consists of option contracts whose pricing structure induces users to reveal the true likelihoods that they will purchase a given resource. Users are also allowed to adjust their options as their likelihood changes. This scheme helps users save cost and the providers to plan ahead so as to reduce the risk of under-utilization and overbooking. The mechanism extracts revenue similar to that of a monopoly provider practicing temporal pricing discrimination with a user population whose preference distribution is known in advance.
Empirical constraints on the evolution of the relationship between black hole and galaxy mass: scatter matters

I investigate whether useful constraints on the evolution of the relationship between galaxy mass (m gal ) and black hole (BH) mass (m BH ) can be obtained from recent measurements of galaxy stellar mass functions and quasi-stellar object (QSO) bolometric luminosity functions at high redshift. I assume a simple power-law relationship between m gal and m BH , as implied by BH mass measurements at low redshift, and consider only evolution in the zero-point of the relation. I argue that one can obtain a lower limit on the zero-point evolution by assuming that every galaxy hosts a BH, shining at its Eddington rate. One can obtain an upper limit by requiring that the number of massive BH at high redshift does not exceed that observed locally. I find that, under these assumptions, and neglecting scatter in the mg al -m BH relation, BH must have been a factor of ∼2 larger at z ∼ I and five to six times more massive relative to their host galaxies at z ∼ 2. However, accounting for intrinsic scatter in m gal -m BH considerably relaxes these constraints. With a logarithmic scatter of 0.3-0.5 dex in m BH at fixed m gal , similar to estimates of the intrinsic scatter in the observed relation today, there are enough massive BH to produce the observed population of luminous QSOs at z ∼ 2 even in the absence of any zero-point evolution. Adopting more realistic estimates for the fraction of galaxies that host active BH and the Eddington ratios of the associated quasars, I find that the zero-point of the m gal -m BH relation at z ∼ 2 cannot be much more than a factor of 2 times larger than the present-day value, as the number of luminous quasars predicted would exceed the observed population.
Numerical Simulation of the In-Situ Upgrading of Oil Shale

This paper (SPE 118958) 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 3 November 2008. Revised manuscript received for review 22 September 2009. Paper peer approved 30 September 2009. Summary Oil shale is a highly abundant energy resource, though commercial production has yet to be realized. Thermal in-situ upgrading processes for producing hydrocarbons from oil shale have gained attention recently, however, in part because of promising results reported by Shell using its in-situ conversion process (Crawford et al. 2008). This and similar processes entail heating the oil shale to approximately 700°F (371°C), where the kerogen in the shale decomposes through a series of chemical reactions into liquid and gas products. In this paper, we present a detailed numerical formulation of the in-situ upgrading process. Our model, which can be characterized as a thermal/compositional, chemical reaction, and flow formulation, is implemented into Stanford’s General Purpose Research Simulator (GPRS). The formulation includes strongly temperature-dependent kinetic reactions, fully compositional flow and transport, and a model for the introduction of heat into the formation through downhole heaters. We present detailed simulation results for representative systems. The model and heating patterns are based on information in Shell publications; chemical-reaction and thermodynamic data are from previously reported pyrolysis experiments. After a relatively modest degree of parameter adjustment (with parameters restricted to physically realistic ranges), our results for oil and gas production are in reasonable agreement with available field data. We also investigate various sensitivities and show how production is affected by heater temperature and location. The ability to model these effects will be essential for the eventual design and optimization of in-situ upgrading operations.
Amino acids as precursors to indolizidine alkaloids

Abstract Enantiocontrolled synthesis of indolizidine alkaloids δ-coniceine [(−)-(R)-octahydroindolizine] and (+)-(1S, 8aS)-1-hydroxyindolizidine, the biosynthetic precursor of slaframine, have been achieved through a condensation of L-prolinal and 3R,2S-hydroxyprolinal, respectively, with a 3-carbon synthon.
Solution Conformations of Mycothiol Bimane, 1-d-GlcNAc-α- (1 → 1)-d-myo-Ins and 1-d-GlcNAc-α-(1 → 1)-l-myo-Ins

Mycothiol is an abundant small molecular weight thiol found only in actinomycetes, which include mycobacteria. Mycothiol biosynthetic and detoxification enzymes are novel and unique to actinomycete...
Preparation of Magnesium Aluminate Spinel Containing Controlled Amounts of 17O Isotope

Magnesium aluminate spinel (MgAl2O4) with an 17O enrichment (17O/OTot) of about 23 at.% was prepared by reacting fine mixtures of aluminum hydroxide (enriched with 17O) and magnesium oxide of normal isotopic content. The material was prepared for experiments in which the radiation damage produced in a fusion reactor is simulated by fission reactor exposures. The powder mixtures were obtained by hydrolyzing, with water containing the 17O iostope, a mixture of aluminum isopropoxide and magnesium oxide powder. The mixture was converted into pure spinel by a series of heat treatments and grindings. Essentially fully dense bodies, which contained about 45% of the 17O isotope initially present in the water, were successfully fabricated provided that all thermal treatments were conducted in argon or vacuum atmospheres.
Leaders or Laggards: engendering sub-national governance through women's policy machineries in Spain and Poland

More than three decades of international best practice and a rich body of scholarship demonstrate that women's policy machinery (WPM) is a crucial tool for promoting feminist policymaking. A new and unstudied form of WPM is emerging at the sub-national level. In this paper, we examine the effects of (1) regional leftist party governance and (2) sub-state durability on feminist policymaking. We employ Stetson and Mazur's model of effective, feminist WPM and operationalize policy Influence and Access provided to feminist groups. Drawing on four regional cases within Spain and Poland, we use field research, interviews, and party documents to examine whether regional leftist party governance and federalized state structure are associated with WPM ‘Leaders’ in feminist policymaking. We find that regional leftist governance is associated with WPMs that offer feminist policy and empower feminist groups; however, sub-state durability modifies the impact of party governance. We conclude with suggestions for furthe...
Cucurbituril chemistry: a tale of supramolecular success

This review highlights the past six year advances in the blossoming field of cucurbit[n]uril chemistry. Because of their exceptional recognition properties in aqueous medium, these pumpkin-shaped macrocycles have been generating some tremendous interest in the supramolecular community. They have also become key units in various self-organizing and stimulus-controlled assemblies, as well as in advanced materials and drug carriers. The scope of this review is limited to the main family of cucurbit[n]urils (n = 5, 6, 7, 8, 10). The reader will find an overview of their preparation, their physicochemical and biological properties, as well as their recognition abilities towards various organic and inorganic guests. Detailed thermodynamic and kinetic considerations, as well as multiple applications including supramolecular catalysis are also discussed.