cssi/SciSciGPT-SciSciNet huggingface dataset:
Spin-induced Disk Precession in Sagittarius A*

In Sgr A* at the Galactic center, by far the closest and easiest supermassive black hole we can study, the observational evidence is increasingly pointing to the presence of a compact, hot, magnetized disk feeding the accretor. In such low Mach number plasmas, forces arising, e.g., from pressure gradients in the plasma, can altogether negate the warping of disks around Kerr black holes caused by the Bardeen-Petterson effect and can lead to coherent precession of the entire disk. In this paper, we present for the first time highly detailed three-dimensional smoothed particle hydrodynamics (SPH) simulations of the accretion disk evolution in Sgr A*, guided by observational constraints on its physical characteristics, and conclude that indeed the Bardeen-Petterson effect is probably absent in this source. Given what we now understand regarding the emission geometry in this object, we suggest that a ~50-500 days modulation in Sgr A*'s spectrum, arising from the disk precession, could be an important observational signature; perhaps the ~106 days period seen earlier in its radio flux, if confirmed, could be due to this process. On the other hand, if future observations do not confirm this long modulation in Sgr A*'s spectrum, this would be an indication either that the disk size or orientation is very different from current estimates, that the black hole is not spinning at all (unlikely), or that our current understanding of how it produces its radiative output is incorrect.
Comparison of image registration based measures of regional lung ventilation from dynamic spiral CT with Xe-CT

Purpose: Regional lung volume change as a function of lung inflation serves as an index of parenchymal and airway status as well as an index of regional ventilation and can be used to detect pathologic changes over time. In this paper, the authors propose a new regional measure of lung mechanics—the specific air volume change by corrected Jacobian. The authors compare this new measure, along with two existing registration based measures of lung ventilation, to a regional ventilation measurement derived from xenon-CT (Xe-CT) imaging. Methods: 4DCT and Xe-CT datasets from four adult sheep are used in this study. Nonlinear, 3D image registration is applied to register an image acquired near end inspiration to an image acquired near end expiration. Approximately 200 annotated anatomical points are used as landmarks to evaluate registration accuracy. Three different registration based measures of regional lung mechanics are derived and compared: the specific air volume change calculated from the Jacobian (SAJ); the specific air volume change calculated by the corrected Jacobian (SACJ); and the specific air volume change by intensity change (SAI). The authors show that the commonly used SAI measure can be derived from the direct SAJ measure by using the air-tissue mixture model and assuming there is no tissue volume change between the end inspiration and end expiration datasets. All three ventilation measures are evaluated by comparing to Xe-CT estimates of regional ventilation. Results: After registration, the mean registration error is on the order of 1 mm. For cubical regions of interest (ROIs) in cubes with size 20 mm × 20 mm × 20 mm, the SAJ and SACJ measures show significantly higher correlation (linear regression, averager2 = 0.75 and r2 = 0.82) with the Xe-CT based measure of specific ventilation (sV) than the SAI measure. For ROIs in slabs along the ventral-dorsal vertical direction with size of 150 mm × 8 mm × 40 mm, the SAJ, SACJ, and SAI all show high correlation (linear regression, average r2 = 0.88, r2 = 0.92, and r2 = 0.87) with the Xe-CT based sV without significant differences when comparing between the three methods. The authors demonstrate a linear relationship between the difference of specific air volume change and difference of tissue volume in all four animals (linear regression, average r2 = 0.86). Conclusions: Given a deformation field by an image registration algorithm, significant differences between the SAJ, SACJ, and SAI measures were found at a regional level compared to the Xe-CT sV in four sheep that were studied. The SACJ introduced here, provides better correlations with Xe-CT based sV than the SAJ and SAI measures, thus providing an improved surrogate for regional ventilation.
STRUCTURAL CHARACTERIZATION OF THE GALACTOXYLOMANNAN OF CRYPTOCOCCUS NEOFORMANS CAP67

The galactoxylomannan (GalXM) obtained from the culture supernatant of an acapsular mutant of Cryptococcus neoformans Cap67 was purified by Concanavalin A affinity, ion-exchange, and gel-filtration chromatographies. The structure of GalXM was determined by methylation analysis and by 1D and 2D NMR spectroscopic studies of the intact polysaccharide and of the oligosaccharide fragments generated by Smith degradation and by acetolysis. GalXM is a complex polysaccharide with an α-(1→6)-galactan backbone. The polysaccharide is branched at C-3 of alternate Gal units of the backbone. C-3 is the point of attachment of the oligosaccharide side chains comprised of α-d-Man-(1→3)-α-d-Man-(1→4)-β-d-Gal-substituted with zero to three terminal β-Xyl residues as shown in the following structure: Figure options Download full-size image Download as PowerPoint slide
Estimating the Causal Impact of Recommendation Systems from Observational Data

Recommendation systems are an increasingly prominent part of the web, accounting for up to a third of all traffic on several of the world's most popular sites. Nevertheless, little is known about how much activity such systems actually cause over and above activity that would have occurred via other means (e.g., search) if recommendations were absent. Although the ideal way to estimate the causal impact of recommendations is via randomized experiments, such experiments are costly and may inconvenience users. In this paper, therefore, we present a method for estimating causal effects from purely observational data. Specifically, we show that causal identification through an instrumental variable is possible when a product experiences an instantaneous shock in direct traffic and the products recommended next to it do not. We then apply our method to browsing logs containing anonymized activity for 2.1 million users on Amazon.com over a 9 month period and analyze over 4,000 unique products that experience such shocks. We find that although recommendation click-throughs do account for a large fraction of traffic among these products, at least 75% of this activity would likely occur in the absence of recommendations. We conclude with a discussion about the assumptions under which the method is appropriate and caveats around extrapolating results to other products, sites, or settings.
Cycloaddition-rearrangement of cyclohexadienol ethers. A versatile and selective synthesis of cyclopentenoid systems

Abstract 1,4-Cyclohexadienol ethers prepared by the Birch reduction of alkyl aryl ethers react at ambient pressure and moderate temperatures with p-bromobenzenesulfonyl azide to yield cyclopentenecarboximidates. The cycloaddition-rearrangement is highly specific for the more electron rich of the two double bonds of the diene.
PRIMARY BREAKUP IN LIQUID-GAS MIXING LAYERS

An experimental study of primary breakup in the nearinjector region of large diameter (5.0 and 9.5 mm) liquid jets in still air is described. Measurements involved flash photography and holography to provide flow visualization and drop size distributions for initially nonturbulent liquids (water, n-heptane and various glycerol mixtures) having various jet exit velocities. Drop sizes after primary breakup satisfied Simmons' universal root normal distribution and can be characterized solely by their SMD. The SMD increased with distance from the jet exit and then remained nearly constant within a fully-developed primary breakup region. SMD measurements in the fully-developed regime did not agree with existing expressiops based on unstable surface wave growth. However, an expression based on stripping-type breakup due to boundary layer growth in the liquid along the windward side of surface waves yielded a reasonably good correlation of present SMD measurements. The nature of this primary breakup correlation implies that secondary breakup is a dominant feature of liquidgas mixing layers.
Il est garçon: Marginal Abidjanais masculinity and the politics of representation

Abstract Using barbershop signs in Abidjan, Cote d’Ivoire, this paper explores images of idealized masculinities that reflect pervasive themes in the lives of marginal Abidjanais men. I argue that men engage in a politics of representation that stresses their likeness to icons from the African diaspora. Global, black and male—the images embody the desires and disappointments of marginal Abidjanais men. Global, the images indicate belonging to the world beyond Africa. Black, the images affirm racialized identities denigrated by colonial domination and mass media hegemony. Male, the images reflect the disproportionately gendered disempowerment that African men experience as a consequence of neoliberal restructuring. Marginal Abidjanais men's relationship to the global economy having shifted from exploitative to excluded, the images suggest a consumption-oriented masculinity that connects them to global capitalism as consumers but not to their hoped-for families as providers.
Lefort, the Philosopher of 1989

Let us leave behind the journalistic commonplace, the revolutions of 1989. The actors themselves, as we know, spoke of self-limiting, peaceful, velvet, and negotiated revolutions, terms all indicating distance from the revolutionary tradition they knew all too well. Even in South Africa in the 1990s, few spoke of revolution during what was indeed the radical transformation of the system of apartheid. The analysts, if they did not adopt the terms of the actors, spoke of regime change, democratic transition, or even revolution.
Parametric GLRT for Multichannel Adaptive Signal Detection

This paper considers the problem of detecting a multichannel signal in the presence of spatially and temporally colored disturbance. A parametric generalized likelihood ratio test (GLRT) is developed by modeling the disturbance as a multichannel autoregressive (AR) process. Maximum likelihood (ML) parameter estimation underlying the parametric GLRT is examined. It is shown that the ML estimator for the alternative hypothesis is nonlinear and there exists no closed-form expression. To address this issue, an asymptotic ML (AML) estimator is presented, which yields asymptotically optimum parameter estimates at reduced complexity. The performance of the parametric GLRT is studied by considering challenging cases with limited or no training signals for parameter estimation. Such cases (especially when training is unavailable) are of great interest in detecting signals in heterogeneous, fast changing, or dense-target environments, but generally cannot be handled by most existing multichannel detectors which rely more heavily on training at an adequate level. Compared with the recently introduced parametric adaptive matched filter (PAMF) and parametric Rao detectors, the parametric GLRT achieves higher data efficiency, offering improved detection performance in general.
Is chemiluminescence an index of hepatic lipoperoxidation accompanying chloroform anesthesia

Hepatic lipoperoxidation by highly reactive metabolites produced during biodegradation of chloroform is believed to cause delayed hepatic necrosis. Chemiluminescence occurs during interaction of these metabolites with a lipid membrane. We have made continuous in vivo measurements of hepatic light output in the phenobarbital-induced rat breathing either air or chloroform vaporized in air. The data permitted direct estimation of the time course of chloroform-induced lipoperoxidation. These potentially toxic events began 15 min after initiation of anesthesia and continued for the duration of the study. Chemiluminescence did not occur with inhalation of isoflurane, an anesthetic undergoing minimal biodegradation.
A Comprehensive Profile of the Working Poor

In this paper, a comprehensive profile of the 'working poor' is presented using data from the 2003 March Supplement of the Current Population Survey. We test an earnings model with effective cost constraints. The dependent variable is the likelihood of an employed individual being a member of the working poor. The explanatory variables are the worker's occupation and firm characteris- tics, and cost constraints comprising, on the one hand, the worker's family char- acteristics (notably family income), and, on the other, the costs to the worker of signals used by firms in making employment decisions. These include not only the cost of education but also what we call 'discriminatory signals', e.g. gender, race, ethnicity and citizenship status. The paper provides new insight into the complex set of relationships between the signaling variables themselves, between signals and occupations, and between industries and occupations, in the formation of relative wage rates.
High-Order Flux Correction for Viscous Flows on Arbitrary Unstructured Grids

A novel high-order method, termed flux correction, previously formulated for inviscid flows, is extended to viscous flows on arbitrary triangular grids. The correction method involves the addition of truncation error-canceling terms to the second-order linear Galerkin (node-centered finite volume) scheme to produce a third-order inviscid and fourth-order viscous scheme. The correction requires minimal modification of the underlying second-order scheme. As such, the method retains many of the advantages of traditional finite volume schemes, including robust shock capturing, low algorithmic complexity, and solver efficiency. In addition, we extend the scheme to unsteady flows. Verification and validation studies in two dimensions are presented. Significant improvement in accuracy is observed in all cases, with between 30---70 % increase in computational cost over a second-order finite volume method.
Results on the fundamental gain of memory-assisted universal source coding

Many applications require data processing to be performed on individual pieces of data which are of finite sizes, e.g., files in cloud storage units and packets in data networks. However, traditional universal compression solutions would not perform well over the finite-length sequences. Recently, we proposed a framework called memory-assisted universal compression that holds a significant promise for reducing the amount of redundant data from the finite-length sequences. The proposed compression scheme is based on the observation that it is possible to learn source statistics (by memorizing previous sequences from the source) at some intermediate entities and then leverage the memorized context to reduce redundancy of the universal compression of finite-length sequences. We first present the fundamental gain of the proposed memory-assisted universal source coding over conventional universal compression (without memorization) for a single parametric source. Then, we extend and investigate the benefits of the memory-assisted universal source coding when the data sequences are generated by a compound source which is a mixture of parametric sources. We further develop a clustering technique within the memoryassisted compression framework to better utilize the memory by classifying the observed data sequences from a mixture of parametric sources. Finally, we demonstrate through computer simulations that the proposed joint memorization and clustering technique can achieve up to 6-fold improvement over the traditional universal compression technique when a mixture of non-binary Markov sources is considered.
Assembly partitioning along simple paths: the case of multiple translations

We consider the following problem that arises in mechanical assembly planning: given an assembly, identify a subassembly that can be removed as a rigid object without disturbing the rest of the assembly. This is the assembly partitioning problem. Specifically, we consider planar assemblies of simple polygons and subassembly removal paths consisting of a single finite translation followed by a translation to infinity. Such paths are typical of the capabilities of simple actuators in fixed automation and other high-volume assembly machines. We present a polynomial-time algorithm to identify such a subassembly and removal path or report that none exists. In addition, we extend this algorithm and analysis to removal paths consisting of a small number k > 2 of translations. We discuss extending the algorithm to three dimensions and to other types of motions typical in non-robotic automated assembly.
Asymmetric syntheses of α-methyl γ-amino acid derivatives.

This project was undertaken to demonstrate the potential of asymmetric hydrogenations mediated by the chiral, carbene-oxazoline analogue of Crabtree’s catalyst “cat” in asymmetric hydrogenations of allylic amine derivatives of amino acids. Peripheral features of the substrates (protecting groups, functional groups related by redox processes, and alkene geometries) were varied to optimize the stereochemical vectors exerted by the substrate and align them with the catalyst vector. N-Acetyl-protected, O-TBDPS-protected allylic substrates 9a–e emerged as the best for this reaction; syn-products were formed from the E-alkenes, while the Z-isomers gave anti-target materials, both with high diastereoselectivities. This study featured asymmetric catalysis to elaborate optically active substrates into more stereochemically complex chirons; we suggest that the approach used, optimization of stereocontrol by varying peripheral aspects of the substrate, tends to be easier than de novo catalyst design for each substra...
Financial Characteristics of North Dakota Farms 2003-2004

The performance of over 500 North Dakota farms, 2003-2004, is summarized using 16 financial measures. Farms are categorized by geographic region, farm type, farm size, gross cash sales, farm tenure, net farm income, debt-to-asset, and age of farmer to analyze relationships between financial performance and farm characteristics. Five year averages, 1999-2003, and farm financial trends for the 1995-2004 period are also presented. Year-to-year changes in median net farm income averaged nearly 40 percent from 1995 to 2004. Median net farm income fell slightly in 2004 to $44,912, after reaching a 10-year high, $49,181 in 2003. Financial performance was lowest in 1997 and 1998 when over one-half of farms could not make scheduled term debt payments. In 1999, 2000, 2003, and 2004 the rate of return on equity exceeded the rate of return on assets, which indicates that debt capital was employed profitably. The interest expense as a percent of gross revenue was 5.6 in 2003 and 2004, the lowest in the past 10 years. It had improved six consecutive years. From 1995 to 2004 the Red River Valley has had stronger profitability, solvency and repayment capacity measures than other regions. Crop farms from 1995-2004 have been larger, as measured by gross sales, and have had better solvency and profitability than livestock farms. Farms with sales less than $100,000 were twice as likely to have debt-to-asset higher than 70 percent than were farms with sales greater than $250,000. Farms that own some crop land, but less than 40 percent and are more likely to be crop farms, farm more acreage, and have larger sales, are typically the most profitable.
Nuclear morphology measurements using Fourier domain low-coherence interferometry

We have developed Fourier domain low coherence interferometry (fLCI), a novel optical interferometry method for obtaining depth-resolved spectral information, specifically for the purpose of determining the size of scatterers by measuring their elastic scattering properties. The optical system achieves depth resolution by using coherence gating, enabled by the use of a white light source in a Michelson interferometer and detection of the mixed signal and reference fields with a spectrograph. The measured spectrum is Fourier transformed to obtain the axial spatial cross-correlation between the signal and reference fields providing depth-resolution. The spectral dependence of scattering by the sample is determined by windowing the spectrum to measure the scattering amplitude as a function of wavenumber (k = 2 Pi / lambda, where lambda is the wavelength). We present a new common path confgiuration fLCI optical system and demonstrate its capabilities by presenting results which determine the size of cell nuclei in a monolayer of T84 epithelial cells.
The Time Variation of Risk and Return in Foreign Exchange Markets: A General Equilibrium Perspective

This article successively introduces variable velocity, durability, and habit persistence in a standard two-country general equilibrium model and explores their effects on the variability of exchange rate changes, forward premiums, and the foreign exchange risk premium. A new feature of the model is that agents make decisions at a weekly frequency and face conditionally heteroskedastic shocks. Nevertheless, even the most complex model fails to deliver sufficiently variable risk premiums without causing forward premiums and exchange rates to be excessively variable. Unlike previous models, the model can roughly match the persistence of forward premiums. Article published by Oxford University Press on behalf of the Society for Financial Studies in its journal, The Review of Financial Studies.
On the Variation of Deuterium and Oxygen Abundances in the Local Interstellar Medium

The first observations of deuterium and oxygen in the local interstellar medium (LISM) obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) can be used to search for local abundance variations. While the very limited sample of these first data may be consistent with no variations, they do offer a hint of anticorrelated variations between D/H and O/H. If confirmed by more data (which will require independently determined, accurate H I column densities), these hints suggest that observations of interstellar gas within a few kiloparsecs of the solar neighborhood will reveal clear signs of the evolution of the abundance of deuterium from there and then (the big bang) to here and now (the local interstellar medium of the Galaxy).
Soot processes in a strongly radiating turbulent flame from laser scattering/extinction experiments

Abstract Soot formation within a highly luminous turbulent non-premixed flame burning acetylene in air was investigated by conducting laser scattering and extinction experiments. Mean soot volume fractions, spherule diameters, and aggregate sizes were exclusively characterized based on an optical interpretation that can properly account for the actual particulate morphology. This allowed decoupling of surface growth and oxidation from the unavoidable aggregation process and therefore provided accurate descriptions of turbulent soot dynamics. The present experiments broadened the database in a lightly sooting ethylene flame previously considered so that the effects of fuel type on particle evolution within turbulent flames could be explored. The relatively high particle concentrations in the acetylene flame also offered conditions that are encountered in many practical combustors operating at elevated pressures, e.g. diesel engines. The findings reported here are relevant not only to developing computational models for accurate predictions of radiative transfer but also to controlling pollutant emissions from combustion systems.
Asymmetric Intermolecular Boron Heck-Type Reactions via Oxidative Palladium(II) Catalysis with Chiral Tridentate NHC-Amidate-Alkoxide Ligands

Chiral dimeric tridentate NHC-amidate-alkoxide palladium(II) complexes, 3a and 3b, effected oxidative boron Heck-type reactions of aryl boronic acids with both acyclic and cyclic alkenes at room temperature to afford the corresponding coupling products with high enantioselectivities. The high degree of enantioselection, far superior to existing methods, stems from differences in the nonbonding interactions in the proposed transition states, due to the influence from bulky substituents of the alkene substrates and the "counter axial groups" of the palladium(II) catalysts.
Total Synthesis and Stereochemistry of Cytoblastin

The first total synthesis and stereochemical assignment of cytoblastin were reported. Key steps included the palladium-mediated coupling of N-SEM-7-bromoindolactam V ((-)-11) with allylstannane c-13, and osmium tetroxide-mediated dihydroxylation of 14, both of which were stereoselective. The stereochemistry of cytoblastin was determined as 1A via spectroscopic analysis of the pentacyclic derivative 21 of cytoblastin. A connection was then made between the stereochemistry so elucidated and the Kishi/Rando hypothesis for the structural correlation between (S)-1,2-diacylglycerol and tumor promoters for the process of protein kinase C activation.
The Transit Light Curve Project. III. Tres Transits of TrES-1

We present z-band photometry of three consecutive transits of the exoplanet TrES-1, with an accuracy of 0.15% and a cadence of 40 s. We improve on estimates of the system parameters, finding in particular that the planetary radius is 1.081 ± 0.029 RJup and the stellar radius is 0.811 ± 0.020 R☉. The uncertainties include both the statistical error and the systematic error arising from the uncertainty in the stellar mass. The transit times are determined to within about 15 s and allow us to refine the estimate of the mean orbital period: P = 3.0300737 ± 0.0000026 days. We find no evidence for starspots or other irregularities that have been previously reported.
DISCRIMINATION OF COHERENT FEATURES IN TURBULENT BOUNDARY LAYERS BY THE ENTROPY METHOD

Entropy in information theory is defined as the expected or mean value of the measure of the amount of self-information contained in the ith point of a distribution series x sub i, based on its probability of occurrence p(x sub i). If p(x sub i) is the probability of the ith state of the system in probability space, then the entropy, E(X) = - sigma p(x sub i) logp (x sub i), is a measure of the disorder in the system. Based on this concept, a method was devised which sought to minimize the entropy in a time series in order to construct the signature of the most coherent motions. The constrained minimization was performed using a Lagrange multiplier approach which resulted in the solution of a simultaneous set of non-linear coupled equations to obtain the coherent time series. The application of the method to space-time data taken by a rake of sensors in the near-wall region of a turbulent boundary layer was presented. The results yielded coherent velocity motions made up of locally decelerated or accelerated fluid having a streamwise scale of approximately 100 nu/u(tau), which is in qualitative agreement with the results from other less objective discrimination methods.
CHILDREN'S RIGHTS AND CHILDREN'S LIVES

A friend who lived in New York could not see the sky from her windows. To discover the day's weather she had to peer at a glass-fronted building opposite, which offered a blurred reflection of part of the sky above her own building. I shall argue that when we take rights as fundamental in looking at ethical issues in children's lives we also get an indirect, partial and blurred picture. If no more direct, clearer and fuller account can be had, we will have to rely on any oblique and partial light which a theory of children's fundamental rights provides. If a clearer, more direct and more complete view of ethical aspects of children's lives is available, we would have good reason to prefer it. We may begin with a reminder of the appeal and importance of thinking in terms of children's rights. Children easily become victims. If they had rights, redress would be possible. Rather than being powerless in the face of neglect, abuse, molestation and mere ignorance they (like other oppressed groups) would have legitimate and (in principle) enforceable claims against others. Although they (unlike many other oppressed groups) cannot claim their rights for themselves, this is no reason for denying them rights. Rather it is reason for setting up institutions that can monitor those who have children in their charge and intervene to enforce rights. The Aristotelian thought that justice is a relation between equals, so inappropriate in dealings with children, is to be rejected. The lives of children are no private matter, but a public concern which can be met by fostering children's rights. Many aspects of this view seem to me plausible. I shall not query the thought that children's lives are a public concern or the aim of securing positive (legal, institutional, customary) rights for children. I shall, however, query whether children's positive rights are best grounded by appeals to fundamental (moral, natural, human) rights. This conclusion does not threaten children's positive rights, which may have other grounds; nor does it deny that children have fundamental rights. Rather I shall
Decentralized indirect adaptive control of interconnected systems

Continuous time decentralized indirect adaptive controllers are proposed for a large-scale system composed of N interconnected linear subsystems with unknown parameters. Each local adaptive law utilizes a normalizing signal which is generated using the local input and the outputs of all the subsystems. This requires the exchange of output signals between the different subsystems, so that the scheme is no longer totally decentralized. Nevertheless, the degree of computational complexity is about the same as that of a totally decentralized scheme and this makes the scheme very attractive.
Navier-Stokes analysis of flow and heat transfer inside high-pressure-ratio transonic turbine blade rows

A detailed numerical study of the flow and the heat transfer inside high-pressure-ratio transonic/supersonic turbine blade rows is described. A high-order upwinding relaxation method is used to solve the Reynoldsaveraged Navier-Stokes equation inside three different turbine blade rows. A two-equation turbulence model with a low-Reynolds-n umber modification is used to describe turbulent shear stress and turbulent heat flux. The numerical results are compared with available experimental data on two-dimensional geometries. It is found that very complex flow phenomena near the trailing edge of transonic turbine blade rows can be very well predicted numerically, and the method can be used in the development of new designs for HP turbines.
The Origins and Nature of the Great Slump, Revisited

M ore than a decade has passed since the Economic History Society last published a survey of the depression of the I930s. That survey, Fearon's The origins and nature of the Great Slump, I929-I932, proved to be one of the best-selling titles in the 'Studies in Economic and Social History' series sponsored by the Society.2 The appeal of Fearon's pamphlet was that it treated the Depression of the I930s as a global phenomenon. Rather than focusing on events in the United States, as had the most influential works of preceding years, Fearon treated the US as but one of many countries succumbing to the slump and emphasized the linkages between them.3 He resurrected an earlier literature in which the depression of the I930S was seen as resulting from instabilities that had developed over the course of previous decades. Implicit in his account, fully half of which was devoted to World War i and the I920S, was the notion that the origins of the slump were somehow connected to structural features of the interwar economy. A disturbing feature of Fearon's survey was the lack of consensus it revealed on the central issues. The events requiring explanation were clearly identified: the onset of the slump, the persistent downward spiral, the inception of recovery. But for each of these events there seemed to be many potential explanations and little agreement among scholars. The reader may ask, given this state of affairs, what justifies another survey of such familiar terrain. The answer, I contend, is that the last decade has witnessed a hidden revolution in our understanding of the macroeconomics of the I930s. On many of the central issues raised by the earlier literature, a striking degree of consensus has emerged. There are two reasons for using Fearon's pamphlet as the point of departure for this survey. First, in his attempt to view the Depression as a global phenomenon and to link the economic crisis of the I930S to developments in previous decades, he anticipated trends in the subsequent literature. Second, the comparison serves to highlight how much attention
Spatial Hierarchical Modeling of Precipitation Extremes From a Regional Climate Model

The goal of this work is to characterize the extreme precipitation simulated by a regional climate model (RCM) over its spatial domain. For this purpose, we develop a Bayesian hierarchical model. Since extreme value analyses typically only use data considered to be extreme, the hierarchical approach is particularly useful as it sensibly pools the limited data from neighboring locations. We simultaneously model the data from both a control and future run of the RCM which allows for easy inference about projected change. Additionally, this hierarchical model is the first to spatially model the shape parameter which characterizes the nature of the distribution’s tail. Our hierarchical model shows that for the winter season, the RCM indicates a general increase in 100-year precipitation return levels for most of the study region. For the summer season, the RCM surprisingly indicates a significant decrease in the 100-year precipitation return level.
A useful benzannulation reaction

Abstract [(2-Alkynyl)-benzoyl]-acetate esters undergo cycloaromatization in good yield upon treatment with CSA in refluxing chloroform.
Effects of Sm2O3 and Gd2O3+ Nd2O3 on Electromechanical Properties of PbTiO3 Ceramics

This paper reports the electromechanical properties of PbTiO{sub 3} ceramics, modified by substitution of Sm or Gd + Nd (same average atomic radius as Sm) for Pb, studied in the range of 6% to 14% substitution. The modified PbTiO{sub 3} ceramics were stable, and the Curie temperature decreased linearly over this composition range. The 10% Sm composition had a large anisotropy in the coupling factor ratio, {ital k{sub t}/k{sub p}}, and a similar, but weaker, effect developed for 12% (1/2 Gd + 1/2 Nd). This indicates that other than average ion size may influence the electromechanical coupling factor ratio.
Activated coagulation time: One tube or two?

Abstract Objectives: To compare activated coagulation time (ACT) management directed by a single ACT determination to that of the average of two simultaneously obtained ACT values Design: Prospective study. Setting: Cardiac operating rooms of a university hospital. Participants: Patients undergoing surgery requiring cardiopulmonary bypass. Interventions: All ACT determinations were performed in duplicate; patients were managed based on the average of the duplicate values, as is customary. Results of all tests were recorded on a spreadsheet, and the management dictated by a randomly chosen single result of each pair was compared with the management directed by the average value of each pair. Predetermined criteria were set for preference of one testing method over the other. Patients were grouped according to preoperative heparin exposure, and results of the two groups were compared. Measurements and Main Results: One hundred patients underwent 683 paired celite ACT determinations. In 565/683 tests (83%), both methods called for identical heparin management responses. Management by the single-tube method would have resulted in supplemental heparin administration 34% more often than management by the average method. The single-tube method would have resulted in withholding supplemental heparin 13 times when the average method called for supplemental heparin administration, a 16% occurrence. The results of the patients with and without preoperative heparin exposure were not significantly different. Conclusions: The results of this study suggest the use of a two-tube average method to guide heparin administration for cardiopulmonary bypass. Preoperative heparin exposure did not influence this outcome.
Home base and knowledge management in international ventures

Abstract This paper examines the scope and sequence of international activities carried out by nascent international ventures. Building on earlier research about foreign direct investment (FDI) and knowledge management in international firms and on the analysis of six international ventures the paper develops a number of propositions. We suggest that international ventures are conceived as ‘international’ because cross-border activities increase the chances of venture survival and growth. We also suggest that, in the early stages of international ventures, cross-border activities that augment the venture's knowledge base are more prevalent than cross-border activities that exploit the venture's knowledge base. Finally, the paper points out research trajectories for more detailed studies of knowledge management in international ventures.
Will rationing guns reduce crime

Abstract Reducing the supply of guns does not necessarily decrease crime, as many economists support. This article explores hazards of gun control and offers an alternative solution for reducing crime, that of enacting laws to permit the carrying of concealed handguns.
Electron correlation effects in ionic hydrogen clusters

We employ density functional, post-Hartree–Fock, and quantum Monte Carlo methods to study the electronic structure, geometries, and behavior of positively charged Hm+ clusters with m=3,5,…,17. Their structure consists of a tightly bound H3+ core ion surrounded by successive solvation shells of H2 molecules. For the largest clusters, we propose new geometries. We find that correlated methods yield the stepwise decrease of enthalpies for dissociation of H2 from the clusters observed in experiments. Our best results are obtained by the diffusion Monte Carlo method, and by including finite temperature entropic effects, we are able to reproduce the experimental dissociation enthalpies with an unprecedented accuracy of less than 0.5 kcal/mol. These benchmark results contrast with erroneous predictions discovered in the density functional approaches. Finally, our analysis of the cluster energy surfaces indicates that under quantum and thermal fluctuations, the outer solvation shells will exhibit pronounced fluctional behavior. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 83: 86–95, 2001
Studying gaugino mass unification at the LHC

We begin a systematic study of how gaugino mass unification can be probed at the CERN Large Hadron Collider (LHC) in a quasi-model independent manner. As a first step in that direction we focus our attention on the theoretically well-motivated mirage pattern of gaugino masses, a one-parameter family of models of which universal (high scale) gaugino masses are a limiting case. We improve on previous methods to define an analytic expression for the metric on signature space and use it to study one-parameter deviations from universality in the gaugino sector, randomizing over other soft supersymmetry-breaking parameters. We put forward three ensembles of observables targeted at the physics of the gaugino sector, allowing for a determination of this non-universality parameter without reconstructing individual mass eigenvalues or the soft supersymmetry-breaking gaugino masses themselves. In this controlled environment we find that approximately 80% of the supersymmetric parameter space would give rise to a model for which our method will detect non-universality in the gaugino mass sector at the 10% level with O(10 fb−1) of integrated luminosity. We discuss strategies for improving the method and for adding more realism in dealing with the actual experimental circumstances of the LHC.
Polarization preserving quantum nondemolition photodetector

A polarization preserving quantum nondemolition photodetector is proposed based on nonlinearities obtainable through quantum coherence effects. An atomic level scheme is devised such that in the presence of strong linearly polarized drive field a coherent weak probe field acquires a phase proportional to the number of photons in the signal mode immaterial of its polarization state. It is also shown that the unavoidable phase-kicks resulting due to the measurement process are insensitive to the polarization state of the incoming signal photon. It is envisioned that such a device would have tremendous applicability in photonic quantum information proposals where quantum information in the polarization qubit is to be protected.
Combinatorial PCPs with Efficient Verifiers

The PCP theorem asserts the existence of proofs that can be verified by a verifier that reads only a very small part of the proof. The theorem was originally proved by Arora and Safra (J. ACM 45(1)) and Arora et al. (J. ACM 45(3)) using sophisticated algebraic tools. More than a decade later, Dinur (J. ACM 54(3)) gave a simpler and arguably more intuitive proof using alternative combinatorial techniques. One disadvantage of Dinur's proof compared to the previous algebraic proof is that it yields less efficient verifiers. In this work, we provide a combinatorial construction of PCPs with verifiers that are as efficient as the ones obtained by the algebraic methods. The result is the first combinatorial proof of the PCP theorem for NEXP (originally proved by Babai et al., FOCS 1990), and a combinatorial construction of super-fast PCPs of Proximity for NP (first constructed by Ben-Sasson et al., CCC 2005).
The maximal {-1,1}-determinant of order 15

We demonstrate the D-optimality of the 15×15 −1,1-matrix discovered independently by Smith and Cohn. This matrix has determinant 25515×214 and is unique up to Hadamard equivalence. In addition, we confirm the previously established values of the maximal determinant for all other odd orders up to 21, excluding 19, and we improve the upper bounds on the maximal determinant in orders 29, 33, and 37.
Dietary Cimetidine and Copper in Eimeria acervulina-Infected Chicks

The effects of varying levels of cimetidine (N"-cyano-N-methyl-N'-(2-[(5-methylimidazol-4-yl)methylthio]-ethyl ) guanidine) on Eimeria acervulina (duodenal coccidiosis)-induced changes in gain, efficiency, duodenal pH, and liver copper concentration of chicks were investigated. In a preliminary trial, gain, efficiency, and duodenal pH were significantly reduced in chicks inoculated one time with 1 X 10(6) sporulated oocysts. Dietary addition of 121 ppm monensin (2-[5-ethyltetrahydro-5-[tetrahydro-3-methyl-5-[tetrahydro-6-hydro xy-6- (hydroxymethyl)-3,5-dimethyl-2H-pyran-2-yl]-2-furyl]-2-furyl]-9-hydroxy- beta-methoxy-alpha, gamma, 2,8-tetramethyl-1,6-dioxaspiro[4.5]decane-7-butyric acid) prevented these coccidiosis-induced aberrations. In subsequent trials, growth rate, feed efficiency, and duodenal pH were reduced by E. acervulina infection, but were unaffected (P greater than 0.10) by dietary addition of 0.01% cimetidine. Linear depressions (P less than 0.05) in gain and efficiency, however, were observed from 0.05 and 0.10% cimetidine additions. Dietary addition of 500 ppm copper increased liver copper levels thirtyfold (P less than 0.01) after 2 weeks. Significant coccidiosis X copper interactions were detected in gain, efficiency, duodenal pH reduction, and liver copper elevation of chicks repeatedly inoculated with 4 X 10(5) sporulated E. acervulina oocysts. Coccidiosis increased liver copper levels (P less than 0.01) of chicks fed excess copper an additional threefold compared with uninfected chicks fed excess copper. Dietary additions of 0.01, 0.05 or 0.10% cimetidine were ineffective in preventing coccidiosis-associated performance and duodenal pH depressions as well as the coccidiosis-induced liver copper elevation. Apparently, host response to cimetidine is minor in comparison to effects of coccidia on duodenal pH. Increased copper solubility at low duodenal pH may explain high tissue copper levels and enhanced copper toxicity due to coccidiosis.
The Internet in India and China

With our colleagues in the Mosaic group, we have done several studies of the state of the Internet in India and in China beginning in 1998. These studies were conducted using a six-dimension framework we have developed for characterizing the state of the Internet in a nation. In 1999, we published a comparison of the state of the Internet in China and India. At that time we found that China had a clear lead in each of our six dimensions. This paper updates the comparison. We compare China and India on our six dimensions and find that China continues to have a substantial lead. We also see that India has made significant strides since our 1999 comparison. After examining the six dimensions, we turn to determinants of the values of those dimensions. What has led to China's lead and the progress that both nations have made recently? We conclude that the following factors were important in shaping China's lead over India. (1) Although Indian universities undertook Internet experiments before those of China, China decided to make the Internet a priority and began building it in earnest before India. (2) Chinese economic reforms, which began in the late 1980s, provided both capital for and openness to the Internet. (3) The pre-Internet Chinese decision to invest in telecommunication infrastructure and information technology industries provided complementary infrastructure and human resources for the Internet. (4) The Chinese ability to execute by decree rather than consensus building followed by legislative and regulatory reform accelerated the diffusion of the Internet. (5) The Chinese were able to create competition among government-owned organizations without taking time for legislative change and the raising of private capital. (6) The Chinese were able to establish competitors to the incumbent telephone company relatively rapidly. Although these factors jump-started the Chinese Internet, and will continue to work in its favor, market forces and openness of access and content may serve India well in the long run. Furthermore, there are also great similarities between the two nations, and we hope they will learn from each other and lead other developing nations.
Gravitational Lensing Magnification without Multiple Imaging

Gravitational lensing can amplify the apparent brightness of distant sources. Images that are highly magnified are often part of multiply imaged systems, but we consider the possibility of having large magnifications without additional detectable images. In rare but nonnegligible situations, lensing can produce a single highly magnified image; this phenomenon is mainly associated with massive cluster-scale halos (1013.5 M☉). Alternatively, lensing can produce multiply imaged systems in which the extra images are either unresolved or too faint to be detectable. This phenomenon is dominated by galaxies and lower mass halos (1012 M☉) and is very sensitive to the inner density profile of the halos. Although we study the general problem, we customize our calculations to four quasars at redshift z ≈ 6 in the Sloan Digital Sky Survey (SDSS), for which Richards et al. (2004) have ruled out the presence of extra images down to an image splitting of Δθ = 03 and a flux ratio of f = 0.01. We predict that 9%-29% of all z ≈ 6 quasars that are magnified by a factor of μ > 10 would lack detectable extra images, with 5%-10% being true singly imaged systems. The maximum of 29% is reached only in the unlikely event that all low-mass (1010 M☉) halos have highly concentrated (isothermal) profiles. In more realistic models in which dwarf halos have flatter (Navarro-Frenk-White) inner profiles, the maximum probability is ~10%. We conclude that the probability that all four SDSS quasars are magnified by a factor of 10 is 10-4. The only escape from this conclusion is if there are many (>10) multiply imaged z ≈ 6 quasars in the SDSS database that have not yet been identified, which seems unlikely. In other words, lensing cannot explain the brightnesses of the z ≈ 6 quasars, and models that invoke lensing to avoid having billion-solar-mass black holes in the young universe are not viable.