cssi/SciSciGPT-SciSciNet huggingface dataset:
Approximate symbolic analysis of large analog integrated circuits

This paper describes a unified approach to the approximate symbolic analysis of large linearized analog circuits. It combines two new approximation-during-computation strategies with a variation of the classical two-graph tree enumeration method. The first strategy is to generate common trees of the two-graphs, and therefore the product terms in the symbolic network function, in the decreasing order of magnitude. The second approximation strategy is the sensitivity-based simplification of two-graphs, which excludes from the two-graphs many circuit elements that have little effect on the network function being derived. Our approach is therefore able to symbolically analyze much larger analog integrated circuits than previously reported, using complete small signal models for the semiconductor devices. We show accurate yet reasonably sized symbolic network functions for integrated circuits with up to 39 transistors whereas previous approaches were limited to less than 15.
Observational bounds on cosmic doomsday

Recently it was found, in a broad class of models, that the dark energy density may change its sign during the evolution of the universe. This may lead to a global collapse of the universe within the time tc ~ 1010–1011 years. Our goal is to find what bounds on the future lifetime of the universe can be placed by the next generation of cosmological observations. As an example, we investigate the simplest model of dark energy with a linear potential V() = V0(1 + α). This model can describe the present stage of acceleration of the universe if α is small enough. However, eventually the field rolls down, V() becomes negative, and the universe collapses. The existing observational data indicate that the universe described by this model will collapse not earlier than tc 10 billion years from the present moment. We show that the data from SNAP and Planck satellites may extend the bound on the `doomsday' time to tc 40 billion years at the 95% confidence level.
Comparison of List-Mode and DIRECT Approaches for Time-of-Flight PET Reconstruction

Early clinical results with time-of-flight (TOF) positron emission tomography (PET) systems have demonstrated the advantages of TOF information in PET reconstruction. Reconstruction approaches in TOF-PET systems include list-mode and binned iterative algorithms as well as confidence-weighted analytic methods. List-mode iterative TOF reconstruction retains the resolutions of the data in the spatial and temporal domains without any binning approximations but is computationally intensive. We have developed an approach [DIRECT (direct image reconstruction for TOF)] to speed up TOF-PET reconstruction that takes advantage of the reduced angular sampling requirement of TOF data by grouping list-mode data into a small number of azimuthal views and co-polar tilts and depositing the grouped events into histo-images, arrays with the sampling and geometry of the final image. All physical effects are included in the system model and deposited in the same histo-image structure. Using histo-images allows efficient computation during reconstruction without ray-tracing or interpolation operations. The DIRECT approach was compared with 3-D list-mode TOF ordered subsets expectation maximization (OSEM) reconstruction for phantom and patient data taken on the University of Pennsylvania research LaBr_3 TOF-PET scanner. The total processing and reconstruction time for these studies with DIRECT without attention to code optimization is approximately 25%-30% that of list-mode TOF-OSEM to achieve comparable image quality. Furthermore, the reconstruction time for DIRECT is independent of the number of events and/or sizes of the spatial and TOF kernels, while the time for list-mode TOF-OSEM increases with more events or larger kernels. The DIRECT approach is able to reproduce the image quality of list-mode iterative TOF reconstruction both qualitatively and quantitatively in measured data with a reduced time.
Lower Bounds on the Depth of Monotone Arithmetic Computations

Consider an arithmetic expression of lengthninvolving only the operations {+,×} and non-negative constants. We prove lower bounds on the depth of any binary computation tree over the same sets of operations and constants that computes such an expression. We exhibit a family of arithmetic expressions that requires computation trees of depth at least 1.5log2n?O(1), thus proving a conjecture of S. R. Kosaraju (1986,in“Proc. of the 18th ACM Symp. on Theory Computing,” pp. 231?239). In contrast, Kosaraju showed how to compute such expressions with computation trees of depth 2log2n+O(1).
Search and Rest Unemployment

This paper extends Lucas and Prescott’s (1974) search model to develop a notion of rest unemployment. The economy consists of a continuum of labor markets, each of which produces a heterogeneous good. There is a constant returns to scale production technology in each labor market, but labor productivity is continually hit by idiosyncratic shocks, inducing the costly reallocation of workers across labor markets. Under some conditions, some workers may be rest-unemployed, waiting for local labor market conditions to improve, rather than engaged in time consuming search. The model has distinct notions of unemployment (moving to a new labor market or waiting for labor market conditions to improve) and inactivity (enjoying leisure while disconnected from the labor market). We obtain closed-form expressions for key aggregate variables and use them to evaluate the model. Quantitatively, we find that in the U.S. economy many more people may be in rest unemployment than in search unemployment.
Estimating Norms of Commutators

We find estimates on the norm of a commutator of the form [f(x), y] in terms of the norm of [x, y], assuming that x and y are bounded linear operators on Hilbert space, with x normal and with spectrum within the domain of f. In particular, we discuss ‖[x2, y]‖ and ‖[x1/2, y]‖ for 0 ≤ x ≤ 1. For larger values of δ = ‖[x, y]‖, we can rigorously calculate the best possible upper bound ‖[f(x), y]‖ ≤ ηf(δ) for many f. In other cases, we have conducted numerical experiments that strongly suggest that we have in many cases found the correct formula for the best upper bound.
The effects of motor parameters on the performance of brushless DC drives

A simulation model for predicting the transient performance of brushless DC drives is described. The model does not require assumptions of phase balance of either the power electronic converter or the motor, nor are idealized waveforms for the induced voltage or phase and mutual inductance terms necessary. The model is applied to drives for which neither equivalent-circuit nor d-q axis analyses are rigorously applicable. Test results establish the degree of correlation of the predictions with a practical example. The model is then used to conduct a sensitivity study that not only explores the degrees of model complexity necessary for adequate representation but also provides guidelines to system designers on the effects of certain practical configurations. The importance of the interaction of converter details, such as the pulse-width-modulated (PWM) technique, and motor parameters, such as the induced voltage waveform, is stressed in the approach considered. >
We've Got to Talk: Emergency Communications and Engineering Ethics

When Hurricane Katrina hit the Gulf Coast of the United States on August 29,2005, it killed over a thousand people, destroyed billions of dollars worth of property, and caused a flood that forced the evacuation of most New Orleans residents for months. The sheer magnitude of the disaster and the sense that more could have been done to prevent loss of life and property have eclipsed some less visible but nonetheless important lessons that the Katrina disaster taught us. This paper deals with the question of emergency communications: how they can fail in disasters such as Katrina and the World Trade Center attacks, why they are so nearly invisible except in times of crisis, where ethical responsibility lies when communications systems fail, and what might be done to improve matters.
Do Tax Amnesties Work? The Revenue Effects of Tax Amnesties During the Transition in the Russian Federation

Governments of all kinds have frequently and increasingly turned to tax amnesties as part of their fiscal programs. An amnesty typically allows individuals or firms to pay delinquent taxes without being subject to some or all of the financial and criminal penalties that the discovery of tax evasion normally brings. Tax amnesties are a controversial revenue-raising tool. Advocates emphasize the immediate and short-run revenue impact, and often argue that future tax revenues may increase if the amnesty induces individuals or corporations not on the tax rolls to participate, and if the amnesty is accompanied by more extensive taxpayer services, better education on taxpayer responsibilities, and stricter post-amnesty penalties for evaders and greater expenditures for enforcement. Critics contend that the actual experiences of many countries indicate that the immediate impact on revenues is almost always quite small. They also question the long-run revenue impact of a tax amnesty, especially if honest taxpayers resent the special treatment of tax evaders and if individuals come to believe that the amnesty is not simply a one-time opportunity. This paper discusses the multiple tax amnesties enacted in the Russian Federation during its main transition period of the 1990s and analyzes the impact of these amnesties on tax collections. We find that these amnesties had little short- or long-term impact on revenues. We conclude that the Russian amnesties, like most other amnesties, seem unlikely to have had significant and demonstrable positive - or negative - impacts on the revenues of the Russian Federation, a conclusion that calls into question their usefulness as a policy instrument.
Optimal Control of Arrays of Microcantilevers

In this paper we will present a model for an array of microcantilevers that are used in Atomic Force Microscopy and nano-scale manufacturing. The microcantilevers are connected to each other through a common base, and are individually actuated. The sensors are also integrated on each microcantilever. We consider the problem of controlling a tightly packed array of identical microcantilevers that are dynamically coupled. This system is an example of a spatially-invariant system with a distributed array of sensors and actuators. We exploit the spatial invariance of the problem to design optimal H 2 controllers for this array. An analytic expression for the optimal controller is derived in the transformed domain, and estimates of the coupling range of the controller is obtained.
Cobordism of disk knots

We study cobordisms and cobordisms rel boundary of PL locally-∞at disk knots D ni2 ,! D n . Any two disk knots are cobordant if the cobordisms are not required to flx the boundary sphere knots , and any two even-dimensional disk knots with isotopic boundary knots are cobordant rel boundary. However, the cobordism rel boundary theory of odd-dimensional disk knots is more subtle. Generalizing results of J. Levine on the cobordism of sphere knots, we deflne disk knot Seifert matrices and show that two higher-dimensional disk knots with isotopic boundaries are cobordant rel boundary if and only if their disk knot Seifert matrices are algebraically cobordant. We also ask which algebraic cobordism classes can be realized given a flxed boundary knot and provide a complete classiflcation when the boundary knot has no 2-torsion in its middle-dimensional Alexander module. In the course of this classiflcation, we establish a close connection between the Blanchfleld pairing of a disk knot and the Farber-Levine torsion pairing of its boundary knot (in fact, for disk knots satisfying certain connectivity assumptions, the disk knot Blanchfleld pairing will determine the boundary Farber-Levine pairing). In addition, we study the dependence of disk knot Seifert matrices on choices of Seifert surface, demonstrating that all such Seifert matrices are rationally S-equivalent, but not necessarily integrally S-equivalent. 2000 Mathematics Subject Classiflcation: Primary 57Q45; Secondary 57Q60, 11E39, 11E81
Development of the HRIBF 25-MV tandem accelerator as a RIB accelerator

Abstract The Holifield facility 25URC tandem accelerator will begin accelerating radioactive ion beams (RIBs) for nuclear structure and astrophysics research in 1996. This paper addresses the development of the accelerator to allow optimum operation with the particular challengesassociated with RIBs. New diagnostics for ultra-low-intensity beams are being installed and the terminal potential stabilization system is being studied to optimize control with these low beam intensities. A new resistor-based voltage-grading system has resulted in more stable operation, as well as allowing operation at the very low terminal potentials which are required for some astrophysics experiments. Also addressed is beam transmission optimization, particularly at low terminal potentials, and operation of the accelerator at high terminal potentials.
Total synthesis of (-)-dictyostatin

A convergent total synthesis of dictyostatin is described. Key features of the synthesis include the use of titanium-mediated cyclizations of (silyloxy)enynes for the synthesis of stereotriads, a subunit coupling by metathesis, and macrocyclization by intramolecular Horner−Wadsworth−Emmons olefination.
Wavelet SDF-Reps: Solid Modeling With Volumetric Scans

This paper describes a new formulation of solid modeling for treating parts derived from volumetric scans (computed tomography, magnetic resonance, etc.) along with parts from traditional computer-aided design operations. Recent advances in segmentation via level set methods produce voxel grids of signed distance values, and we interpolate the signed distance values using wavelets to produce an implicit or function-based representation called wavelet signed distance function representation that provides inherent support for data compression, multiscale modeling, and skeletal-based operations.
A randomized satisfiability procedure for arithmetic and uninterpreted function symbols

We present a new randomized algorithm for checking the satisfiability of a conjunction of literals in the combined theory of linear equalities and uninterpreted functions. The key idea of the algorithm is to process the literals incrementally and to maintain at all times a set of random variable assignments that satisfy the literals seen so far. We prove that this algorithm is complete (i.e., it identifies all unsatisfiable conjunctions) and is probabilistically sound (i.e., the probability that it fails to identify satisfiable conjunctions is very small). The algorithm has the ability to retract assumptions incrementally with almost no additional space overhead. The algorithm can also be easily adapted to produce proofs for its output. The key advantage of the algorithm is its simplicity. We also show experimentally that the randomized algorithm has performance competitive with the existing deterministic symbolic algorithms.
The effect of the type and number of internal control weaknesses and their remediation on audit fees

Purpose – The implementation of compliance procedures associated with the Sarbanes‐Oxley Act of 2002 came at a great cost to most publicly‐traded firms, largely due to the internal control disclosures required by Section 404 of the Act. The purpose of this paper is to contribute to the inquiry on internal control effectiveness by examining the impact of the type (same or different) and number of internal control weaknesses on audit fees. The paper also examines whether firms that remediate continue to incur higher audit fees compared to firms that never disclosed a weakness.Design/methodology/approach – The authors evaluate the impact of internal control weaknesses and their remediation on audit fees using ordinary least squares regression for 9,122 firm year observations (3,096 unique firms) over the time period 2004‐2007.Findings – The authors find: an incremental impact on audit fees of additional material weakness disclosures; firms that report the same material weakness pay higher fees than firms rep...
Mitochondrial DNA genetics and the heteroplasmy conundrum in evolution and disease

The unorthodox genetics of the mtDNA is providing new perspectives on the etiology of the common “complex” diseases. The maternally inherited mtDNA codes for essential energy genes, is present in thousands of copies per cell, and has a very high mutation rate. New mtDNA mutations arise among thousands of other mtDNAs. The mechanisms by which these “heteroplasmic” mtDNA mutations come to predominate in the female germline and somatic tissues is poorly understood, but essential for understanding the clinical variability of a range of diseases. Maternal inheritance and heteroplasmy also pose major challengers for the diagnosis and prevention of mtDNA disease.
On the Sequencing of Structural Reforms

Both OECD and developing economies have embarked on structural reforms aimed at dismantling regulations and reducing the extent of distortions affecting different sectors of their economies. Regardless of the marked differences, both groups have to deal with the problems of the appropriate sequencing and speed of reforms. This paper first critically reviews the LDC related literature on sequencing and speed of structural reforms drawing out features which are of relevance for OECD economies. The paper then develops a formal framework based on a welfare criterion for evaluating different sequencing scenarios. The framework emphasises the microeconomic or efficiency effects of structural policies paying particular attention to the way in which distortions interact both intra and inter temporally. The framework is then used to discuss some of the important issues such as the sequencing of micro and macro reforms ("competition of instruments"), broad front versus sequential ...
Taxes, Spending, and the U.S. Government's March towards Bankruptcy

The United States is moving toward a possible catastrophic fiscal collapse. The country may not get there, but the risk is unmistakable and growing. The 'fiscal language' of taxes, spending, and deficits has played a huge and under appreciated role in the decisions that have pushed the nation in this dangerous direction. Part of the problem is that by focusing only on the current year, deficits permit politicians to ignore what is looming down the road. The bigger problem lies in the belief, shared by people on the left and the right alike, that 'tax cuts' and 'spending cuts' lead to smaller government, when in fact the characterization of any new policy as a change in 'taxes' or in 'spending' is purely a matter of labeling. This book proposes a better fiscal language for US budgetary policy, rooted in economic fundamentals such as wealth distribution and resource allocation in lieu of 'taxes' and 'spending'.
Nanostructural tailoring: Opportunities for molecular engineering in catalysis

This article describes some unique facets of nanostructure processing and the usefulness of this approach for catalysis.
Serum ghrelin is inversely associated with risk of subsequent oesophageal squamous cell carcinoma

Background Gastric atrophy, as determined by a low serum pepsinogen I:II ratio, may be associated with an increased risk of oesophageal squamous cell carcinoma (OSCC). Ghrelin, a hormone which, is also produced in the gastric fundic glands may be a marker of gastric atrophy, but its association with OSCC is not known. Methods To examine the relationship between baseline serum ghrelin concentration and subsequent risk of OSCC, the authors conducted a nested case–control study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) study. 82 cases of OSCC were matched (1:1) by age and date of blood draw to controls from the ATBC study. Serum ghrelin was measured by radioimmunoassay. ORs and 95% CIs were calculated using conditional logistic regression with adjustment for potential confounders. Results For individuals in the lowest quartile of serum ghrelin, compared to those in the highest, the multivariate OR of subsequent OSCC was 6.83 (95% CI 1.46 to 31.84). These associations were dose dependent (p value for trend =0.005 for both), and independent of the effects of low pepsinogen I:II ratio and Helicobacter pylori infection. The significance of these associations remained even for individuals developing OSCC up to 10 years after baseline ghrelin measurement, although they become attenuated after 10 years. Conclusion Lower baseline concentrations of serum ghrelin were associated with an increase in risk of OSCC. Further studies are needed to confirm this finding in other populations and to explore the role of ghrelin in the aetiology of OSCC.
Inverse modeling of interbed storage parameters using land subsidence observations, Antelope Valley, California

[1] We use land-subsidence observations from repeatedly surveyed benchmarks and interferometric synthetic aperture radar (InSAR) in Antelope Valley, California, to estimate spatially varying compaction time constants, τ, and inelastic specific skeletal storage coefficients, S*kv, in a previously calibrated regional groundwater flow and subsidence model. The observed subsidence patterns reflect both the spatial distribution of head declines and the spatially variable inelastic skeletal storage coefficient. Using the nonlinear parameter estimation program UCODE we estimate compaction time constants between 3.8 and 285 years. The S*kv values are estimated by linear estimation and range from 0 to almost 0.09. We find that subsidence observations over long time periods are necessary to constrain estimates of the large compaction time constants in Antelope Valley. The InSAR data used in this study cover only a three-year period, limiting their usefulness in constraining these time constants. This problem will be alleviated as more SAR data become available in the future or where time constants are small. By incorporating the resulting parameter estimates in the previously calibrated regional model of groundwater flow and land subsidence we can significantly improve the agreement between simulated and observed land subsidence both in terms of magnitude and spatial extent. The sum of weighted squared subsidence residuals, a common measure of model fit, was reduced by 73% with respect to the original model. However, the ability of the model to adequately reproduce the subsidence observed over only a few years is impaired by the fact that the simulated hydraulic heads over small time periods are often not representative of the actual aquifer hydraulic heads. Errors in the simulated hydraulic aquifer heads constitute the primary limitation of the approach presented here.
Jupiter and Saturn rotation periods

Abstract Anderson and Schubert [2007. Saturn's Gravitational field, internal rotation, and interior structure. Science 317, 1384–1387 (paper I)] proposed that Saturn's rotation period can be ascertained by minimizing the dynamic heights of the 100 mbar isosurface with respect to the geoid; they derived a rotation period of 10 h 32 m 35 s. We investigate the same approach for Jupiter to see if the Jovian rotation period is predicted by minimizing the dynamical heights of its isobaric (1 bar pressure level) surface using zonal wind data. A rotation period of 9 h 54 m 29.7 s is found. Further, we investigate the minimization method by fitting Pioneer and Voyager occultation radii for both Jupiter and Saturn. Rotation periods of 9 h 55 m 30 s and 10 h 32 m 35 s are found to minimize the dynamical heights for Jupiter and Saturn, respectively. Though there is no dynamical principle requiring the minimization of the dynamical heights of an isobaric surface, the successful application of the method to Jupiter lends support to its relevance for Saturn. We derive Jupiter and Saturn rotation periods using equilibrium theory to explain the difference between equatorial and polar radii. Rotation periods of 9 h 55 m 20 s and 10 h 31 m 49 s are found for Jupiter and Saturn, respectively. We show that both Jupiter's and Saturn's shapes can be derived using solid-body rotation, suggesting that zonal winds have a minor effect on the planetary shape for both planets. The agreement in the values of Saturn's rotation period predicted by the different approaches supports the conclusion that the planet's period of rotation is about 10 h 32 m.
The Food Problem and the Evolution of International Income Levels

In most poor countries, large fractions of land, labor, and other productive resources are devoted to producing food for subsistence needs. We show that a model incorporating the “food problem” can provide new and useful insights into the evolution of international income levels. In particular, we find that the food problem can explain why some countries started to realize increases in per capita output more than 250 years later in history than others. We also show that the food problem has important implications for growth miracles and the speed at which a country converges to its balanced growth path.
On a class of mappings between Riemannian manifolds

Abstract Effects of geometric constraints on a steady flow potential are described by an elliptic-hyperbolic generalization of the harmonic map equations. Sufficient conditions are given for global triviality.
Markets for Cotton By-Products : Global Trends and Implications for African Cotton Producers

This paper analyzes and compares the structure of cotton by-products industries in se-lected countries (Uganda, Tanzania, Benin, and Burkina Faso) in the context of the global vegetable oil market. It reaches several conclusions. First, because the markets for various edible oils are highly integrated with each other, examination of each oil market should be done in conjunction with all other (relevant) edible oil markets. Second, the recent surge in demand for commodities used as feedstocks for biofuels is unlikely to become a new source of growth for the cotton oil market. Third, within the context of deepening the on-going reform efforts in West and Central African countries, cotton by-products should be taken into consideration, both in terms of the cotton price setting mechanism and the size of the organization of the cotton by-products industry. Fourth, trade policies including export bans or import tariffs to protect the domestic crushing industries, and policies that favor crude over refined oils, should be rationalized. Fifth, large cottonseed processing operations using advanced technology, while efficient from a technological perspective, tend not to be economically profitable in the African context. Last, research efforts for new cotton varieties should consider the value of by-products, not just lint.
A Postfiltered DPCM Scheme

Quantization noise constitutes the limiting factor on DPCM performance. For a low number of levels in the quantizer, this noise is also correlated. In this correspondence we present a technique for improving the performance of the DPCM system at a very modest cost. The technique involves the use of an adaptive transversal filter at the receiver output to reduce the effects of quantization noise. The filter is trained at the transmitter and periodic updates sent to the receiver.
The synthesis of perfluoro highly branched heterocyclic fluorine compounds by direct fluorination

Abstract The direct fluorination of hexamethyleneimine, heptamethyleneimine, 2,6-dimethylmorpholine, thiomorpholine, 1,4-dimethylpiperazine and piperazine produced the corresponding perfluorinated products. The 19F NMR spectrum of perfluoro N,N1-difluoropiperazine was found to be temperature- dependent.
New multivariate dependence measures and applications to neural ensembles

We develop two new multivariate statistical dependence measures. First, based on the Kullback-Leibler distance, results in a single value that indicates the general level of dependence among the random variables. Second, based on an orthonormal series expansion of joint probability density functions provides more detail about the nature of the dependence. We apply these dependence measures to the analysis of simultaneous recordings made from multiple neurons, in which dependencies are time-varying and potentially information bearing.
Ground States of the 2D Sticky Disc Model: Fine Properties and N 3/4 Law for the Deviation from the Asymptotic Wulff Shape

We investigate ground state configurations for a general finite number N of particles of the Heitmann-Radin sticky disc pair potential model in two dimensions. Exact energy minimizers are shown to exhibit large microscopic fluctuations about the asymptotic Wulff shape which is a regular hexagon: There are arbitrarily large N with ground state configurations deviating from the nearest regular hexagon by a number of ∼N 3/4 particles. We also prove that for any N and any ground state configuration this deviation is bounded above by ∼N 3/4. As a consequence we obtain an exact scaling law for the fluctuations about the asymptotic Wulff shape. In particular, our results give a sharp rate of convergence to the limiting Wulff shape.
Mexican-Hispanic Self-Employment Entry: The Role of Business Start-Up Constraints:

This article examines causes of the low self-employment rates among Mexican-Hispanics by studying self-employment entry using the 1996 panel of the Survey of Income and Program Participation (SIPP). The data show that Mexican-Hispanics are less likely to be self-employed or enter self-employment, relative to non-Hispanic whites. The authors analyze self-employment by recognizing heterogeneity in business ownership across industries and show that a classification of firms by human and financial capital “intensiveness,” or entry barriers, is effective in explaining differences in entrepreneurship across ethnic groups. The authors show that the lower self-employment entry rates among Mexican-Hispanics are due to lower entry rates into business ownership of firms in relatively high-barrier industries. In fact, Hispanics are more likely to start up a business in a low-barrier industry than whites.
Heterodyne frequency measurements on OCS near 61.76 THz (2060 cm−1)

Abstract Heterodyne measurements have been made on the 10 0 0-00 0 0 and 11 1 0-01 1 0 bands of 16 O 12 C 32 S and 16 O 13 C 32 S and the 10 0 0-00 0 0 band of 16 O 12 C 34 S. These measurements were combined with earlier frequency measurements and Fourier transform measurements to obtain accurate calibration frequencies for the regions 1985 to 2085 and 2550 to 2600 cm −1 .
Proteomic analysis of immediate‐early response plasma proteins after 70% and 90% partial hepatectomy

Partial hepatectomy (PH) induces robust hepatic regenerative and metabolic responses that are considered to be triggered by humoral factors. The aim of the study was to identify plasma protein factors that potentially trigger or reflect the body’s immediate-early responses to liver mass reduction. Male C57BL/6 mice were subjected to sham operation, 70% PH, or 90% PH. Blood was collected from the inferior vena cava at 20, 60, and 180 minutes after surgery. Using a label-free quantitative mass spectrometry-based proteomics approach, we identified 399 proteins exhibiting significant changes in plasma expression between any two groups. Of the 399 proteins, 167 proteins had multiple unique sequences and high peptide ID confidence (>90%) and were defined as priority 1 proteins. A group of plasma proteins largely associated with metabolism is enriched after 70% PH. Among the plasma proteins that respond to 90% PH are a dominant group of proteins that are also associated with metabolism and one known cytokine (platelet factor 4). Ninety percent PH and 70% PH induces similar changes in plasma protein profile. Our findings enable us to gain insight into the immediate-early response of plasma proteins to liver mass loss. Our data support the notion that increased metabolic demands of the body after massive liver mass loss may function as a sensor that calibrates hepatic regenerative response.
A Model of Casino Gambling

We show that prospect theory offers a rich theory of casino gambling, one that captures several features of actual gambling behavior. First, we demonstrate that for a wide range of preference parameter values, a prospect theory agent would be willing to gamble in a casino even if the casino offers only bets with no skewness and with zero or negative expected value. Second, we show that the probability weighting embedded in prospect theory leads to a plausible time inconsistency: at the moment he enters a casino, the agent plans to follow one particular gambling strategy; but after he starts playing, he wants to switch to a different strategy. The model therefore predicts heterogeneity in gambling behavior: how a gambler behaves depends on whether he is aware of the time inconsistency; and, if he is aware of it, on whether he can commit in advance to his initial plan of action. This paper was accepted by Brad Barber, Teck Ho, and Terrance Odean, special issue editors.
On the Relationship between Radio Emission and Black Hole Mass in Galactic Nuclei

We use a comprehensive database of black hole masses (MBH) and nuclear luminosities to investigate the relationship between radio emission and MBH. Our sample covers a wide range of nuclear activity, from nearby inactive nuclei to classical Seyfert 1 nuclei and luminous quasars. Contrary to some previous studies, we find that the radio continuum power, either integrated for the entire galaxy or isolated for the core, correlates poorly with MBH. The degree of nuclear radio loudness, parameterized by the radio-to-optical luminosity ratio R, also shows no clear dependence on MBH. Radio-loud nuclei exist in galaxies with a wide range of MBH, from ~106 to a few times 109 M☉, and in a variety of hosts, from disk-dominated spiral to giant elliptical galaxies. We demonstrate that R is strongly inversely correlated with L/LE, the ratio of nuclear luminosity to the Eddington luminosity, and hence with the mass accretion rate. Most or all of the weakly active nuclei in nearby galaxies are radio-loud, highly sub-Eddington systems that are plausibly experiencing advection-dominated accretion.
LEARNING, COMMITMENT, AND MONETARY POLICY: THE CASE FOR PARTIAL COMMITMENT

This paper examines a class of interest rate rules, studied in Evans and Honkapohja (2003, 2006), that respond to public expectations and to lagged variables. Their work is extended by considering varying levels of commitment that correspond to varying degrees of response to lagged output. Under commitment the policymaker adjusts the nominal rate with lagged output to impact public expectations. Within this class of rules, I provide a condition for non-explosive and determinate solutions. Expecatational stability obtains for any non-negative response to lagged output. Simulation results show that modified commitment, as advocated by Blake (2001), is best under least squares learning. However, in the presence of parameter uncertainty and/or measurement error in the policymaker’s data on public expectations, the best policy is one of partial commitment, where the response to lagged output is less than under modified commitment. The case for partial commitment is strengthened if the gain parameter in the learning mechanism is high, which can be interpreted as the use of few lags by public agents in the formation of expectations or as an indication of low credibility of the policymaker. The appointment of a conservative central banker ameliorates these concerns about modified commitment.
Separating the Components of Default Risk: A Derivative-Based Approach

In this paper, I propose a general pricing framework that allows the risk neutral dynamics of loss given default (Lℚ) and default probabilities (λℚ) to be separately and sequentially discovered. The key is to exploit the differentials in Lℚ exhibited by different securities on the same underlying firm. By using equity and option data, I show that one can efficiently extract pure measures of λℚ that are not contaminated by recovery information. Equipped with this knowledge of pure default dynamics, prices of any defaultable security on the same firm with non-zero recovery can be inverted to compute the associated Lℚ corresponding to that particular security. Using data on credit default swap premiums, I show that, cross-sectionally, λℚ and Lℚ are positively correlated. In particular, this positive correlation is strongly driven by firms' characteristics, including leverage, volatility, profitability and q-ratio. For example, 1% increase in leverage leads to 0.14% increase in λℚ and 0.60% increase in Lℚ.
Warming maximum in the tropical upper troposphere deduced from thermal winds

Climate models and theoretical expectations have predicted that the upper troposphere should be warming faster than the surface. Surprisingly, direct temperature observations from radiosonde and satellite data have often not shown this expected trend. However, non-climatic biases have been found in such measurements. Here we apply the thermal-wind equation to wind measurements from radiosonde data, which seem to be more stable than the temperature data. We derive estimates of temperature trends for the upper tropospheretothelowerstratospheresince1970.Overtheperiodofobservations,wefindamaximumwarmingtrendof0.65±0.47K per decade near the 200hPa pressure level, below the tropical tropopause. Warming patterns are consistent with model predictions except for small discrepancies close to the tropopause. Our findings are inconsistent with the trends derived from radiosonde temperature datasets and from NCEP reanalyses of temperature and wind fields. The agreement with models increases confidence in current model-based predictions of future climate change. It has long been recognized that radiosonde temperature data are a ected by non-climatic artifacts due to station relocations, observation time changes and radiosonde type or design changes 1 . Several investigators have attempted to detect and adjust (that is homogenize) these artefacts using a variety of tools, including statistical procedures, station metadata, various indicators of natural variability (such as volcanic eruptions, vertical coherence) and forecasts from a climate data assimilation system 2‐6 . Despite these attempts, most analyses of radiosondes continue to show less warming of the tropical troposphere since 1979 than reported at the surface 1 . At least one satellite dataset also implies this 7 . By contrast, theoretical and model expectations 7,8 indicate that the troposphere should warm somewhat faster than the surface. Recently, time-varying biases were shown to remain in the radiosonde temperature data, including a daytime cooling bias related to solar heating of the instrument (especially in the stratosphere) 9 . They were significantly larger than the average adjustments that had previously been made, and comparable to the above discrepancies, calling into question whether the adjustments had been adequate. A similar cooling bias was also found in night-time soundings 10,11 . Subsequent attempts to produce better homogenized records have yielded more warming than before 5,12,13 ,
Means and Ends: A Comparative Study of Empirical Methods for Investigating Governance and Performance

Scholars within different disciplines employ a wide range of empirical approaches to understanding how, why and with what consequences government is organized. We first review recent statistical modeling efforts in the areas of education, job-training, welfare reform and drug abuse treatment and assess recent advances in quantitative research designs. We then estimate governance models with two different data sets in the area of job training using three different statistical approaches: hierarchical linear models (HLM); ordinary least squares (OLS) regression models using individual level data; and OLS models using outcome measures aggregated at the site or administrator level. We show that HLM approaches are in general superior to OLS approaches in that they produce (1) a fuller and more precise understanding of complex, hierarchical relationships in government, (2) more information about the amount of variation explained by statistical models at different levels of analysis, and (3) increased generalizability of findings across different sites or organizations with varying characteristics. The notable inconsistencies in the estimated OLS regression coefficients are of particular interest to the study of governance, since these estimated relationships are nearly always the primary focus of public policy and public management research.
Aromatic chloride to nitrile transformation: medicinal and synthetic chemistry

This review highlights the medicinal and synthetic chemistry relevance of replacing an aromatic chloride motif with an aromatic nitrile. We explore the desirable features that this transformation can bring in a drug design sense and the recent synthetic chemistry advances that effect this replacement in a single step.
The Compositions of Kuiper Belt Objects

Objects in the Kuiper belt are difficult to study in detail, even with the best telescopes available. Therefore, for many years, studies of the compositions of these objects were relegated to collections of moderate-quality spectroscopic and photometric data that remained difficult to interpret. Much early effort was put into simple correlations of surface colors and identifications of spectral features, but connecting these observations to a larger understanding of the region remained elusive. The past decade, however, has seen a blossoming in our understanding, a product of the discoveries of larger—and thus easier to study—objects, continued collection of high-quality photometric and spectroscopic observations, and continued work at the laboratory and theoretical levels. Today, we now know of many processes that affect these objects’ surface compositions, including atmospheric loss, differentiation and cryovolcanism, radiation processing, the effects of giant impacts, and the early dynamical excitation of the Kuiper belt. I review the large quantity of data now available and attempt to build a comprehensive framework for understanding the compositions and their causes.
Duty cycle and the increasing star formation history of z ≥ 6 galaxies

We examine the duty cycle (DC) and the star formation history (SFH) for high-redshift galaxies at z ≥ 6 using cosmological hydrodynamic simulations. We find that, even though individual galaxies have bursty SFH, the averaged SFH between z ∼ 15 and 6 can be characterized well by either an exponentially increasing functional form with characteristic time-scales of 70–200 Myr for galaxies with stellar masses Ms ∼ 106 to >1010 M⊙, respectively, or a simple power-law form which exhibits similar mass-dependent time-scales. Using the SFH of individual galaxies, we measure the DC of star formation (DC SFH), i.e. the fraction of time a galaxy of a particular mass spends above a star formation rate (SFR) threshold which would make it observable to the Hubble Space Telescope (HST) during a given epoch. We also examine the fraction of galaxies at a given redshift that are brighter than a rest-frame ultraviolet magnitude (Muv ∼ −18), which is sufficient to make them observable (). We find that both DC SFH and make a sharp transition from zero (for galaxies with ) to unity (for ). The measured DC is also manifested in the intrinsic scatter in the Ms - SFR relationship (∼1 dex) and Ms - Muv relationship (ΔMuv ∼ ±1 mag). We provide analytic fits to the DC as a function of Ms using a sigmoid function which can be used to correct for catalogue incompleteness. We consider the effects of DC to the observational estimate of galaxy stellar mass functions (GSMF) and the SFR density (SFRD), and find that it results in much shallower low-mass end slopes of the GSMF and a reduction of ≳70 per cent of our intrinsic SFRD, making our simulation results more compatible with observational estimates.
The impacts of speed-to-market on new product success: the moderating effects of uncertainty

Time-based strategy is becoming an important weapon to achieve competitive advantage in the current environment of fast-changing technology and customer requirements. Speed-to-market has become the mantra of both researchers and practitioners in new product development (NPD), but there are limited and conflicting findings on the relationship between speed-to-market and product success. A more important question is whether faster is always better. In a study of 692 NPD projects, we examined the relationship between speed-to-market and new product success (NPS) under different conditions of uncertainty. Our results indicate that speed-to-market is generally positively associated with overall NPS, but market uncertainty moderates the direct effect. Speed-to-market is less important to NPS under conditions of low market uncertainty. Our results also suggest that technological uncertainty does not affect the speed-success relationship. The implication is that it is more important to execute a time-based strategy in an unfamiliar, emerging, or fast-changing market than in a familiar, existing, and stable market. The limitations and future research related to these results are discussed.
Dynamical boundary control of two-dimensional wave equations: vibrating membrane on general domain

Dynamical boundary control of a vibrating membrane with edge mass and of general shape is mathematically formulated as an abstract evolutionary system. The approximate controllability and the strong stabilization by linear boundary damping feedback are established by an approach based on LaSalle's invariance principle. The mathematical model and the reduced system can be used to investigate some optimization problems. >
A new method for the investigation of capillary structure.

Numerous physiological conditions as well as behavioral conditions have been shown to influence central nervous system vascular structure. Many of the methods used to investigate these structural alterations take advantage of the visibility of viscous substances (e.g. India ink in gelatin) perfused into the vasculature. The high viscosity of the solution, however, can cause incomplete vessel perfusion. The aim of the present study was to test whether or not capillaries seen in tissue perfused with fixative, embedded in celloidin and stained with Methylene Blue–Azure II (n= 6) could be a useful alternative for the investigation of brain vascular structure. The method was compared to tissue from six rats perfused with India ink in gelatin and stained with cresyl violet. Qualitatively, vessels in the standard perfused tissue embedded in celloidin yielded clear vessels with stained pericytes. The two methods did not differ in branch point to cell ratio, length of individual capillaries, vessel length per mm 3 , and capillary tortuosity. The capillary diameter was greater in the celloidin embedded tissue than in the India ink perfused tissue. Measuring the diameter between vessel walls appears to provide a more accurate measure than the widest distance between India ink pigments. Quantitative comparisons suggest that perfusion with standard fixative followed by embedding in celloidin provides vascular quantification comparable to that from India ink perfused tissue. The present method has several advantages, which include visualization of pericytes, increased probability of complete perfusion, clear view of cells that might otherwise be obscured by opaque vessels, and the possibility of using the alternate cerebral hemisphere for investigation of vascular ultrastructure. © 2002 Elsevier Science B.V. All rights reserved.