cssi/SciSciGPT-SciSciNet huggingface dataset:
Efficient palladium-catalyzed Suzuki-Miyaura coupling of aryl chlorides with arylboronic acids using benzoferrocenyl phosphines as supporting ligands

Abstract Four monodentate benzoferrocenyl phosphines were studied as supporting ligands in palladium-catalyzed Suzuki–Miyaura coupling of aryl chlorides with arylboronic acids. Of these ligands, the more electron-rich and steric demanding benzoferrocenyl dicyclohexyl phosphine was found highly effective for the reaction followed by the benzoferrocenyl diisopropyl phosphine. The corresponding diethyl and diphenyl phosphines are much less active. When the dicyclohexyl phosphine was used, both electron-rich and electron-poor aryl chlorides were coupled with arylboronic acids within 1 h giving good to excellent yields. Chloro-substituted pyridines were also found highly reactive under these conditions giving excellent yields of biaryl products. Sterically hindered biaryls can also be prepared using the dicyclohexyl phosphine as ligand.
Micro-Hall magnetometry studies of thermally assisted and pure quantum tunneling in single molecule magnet Mn12-acetate

We have studied the crossover between thermally assisted and pure quantum tunneling in single crystals of high spin (S=10) uniaxial single molecule magnet Mn12 using micro-Hall effect magnetometry. Magnetic hysteresis experiments have been used to investigate the energy levels that determine the magnetization reversal as a function of magnetic field and temperature. These experiments demonstrate that the crossover occurs in a narrow ( 0.1 K) or broad ( 1 K) temperature interval depending on the magnitude and direction of the applied field. For low external fields applied parallel to the easy axis, the energy levels that dominate the tunneling shift abruptly with temperature. In the presence of a transverse field and/or large longitudinal field these energy levels change with temperature more gradually. A comparison of our experimental results with model calculations of this crossover suggests that there are additional mechanisms that enhance the tunneling rate of low-lying energy levels and broaden the crossover for small transverse fields. © 2001 Elsevier Science Ltd. All rights reserved.
A Brascamp-Lieb type covariance estimate

In this article, we derive a new covariance estimate. The estimate has a similar structure as the Brascamp-Lieb inequality and is optimal for ferromagnetic Gaussian measures. It can be naturally applied to deduce decay of correlations of lattice systems of continuous spins. We also discuss the relation of the new estimate with known estimates like a weighted estimate due to Helffer & Ledoux. The main ingredi.ent of the proof of the new estimate is a directional Poincare inequality which seems to be unknown.
Synergistic catalysis: A powerful synthetic strategy for new reaction development

Synergistic catalysis is a synthetic strategy wherein both the nucleophile and the electrophile are simultaneously activated by two separate and distinct catalysts to afford a single chemical transformation. This powerful catalysis strategy leads to several benefits, specifically synergistic catalysis can (i) introduce new, previously unattainable chemical transformations, (ii) improve the efficiency of existing transformations, and (iii) create or improve catalytic enantioselectivity where stereocontrol was previously absent or challenging. This perspective aims to highlight these benefits using many of the successful examples of synergistic catalysis found in the literature.
Mild Cognitive Impairment and Dementia

Mild cognitive impairment (MCI) is a clinical syndrome thought to represent the transition between normal function and dementia. This review describes data that support the existence of such a transitional phase, outlines the heterogeneity of MCI and how that has influenced the evolving concept of MCI, and discusses the impact of heterogeneity on recent MCI clinical trials.
The First Organically Templated Open‐Framework Niobium Silicate and Germanate Phases: Low‐Temperature Hydrothermal Syntheses of [(C4N2H11)Nb3SiO10] (NSH‐1) and [(C4N2H11)Nb3GeO10] (NGH‐1)

Eight- and six-ring channels built from NbO6 octahedra and SiO4 or GeO4 tetrahedra, respectively, are contained in the structures of the first organically templated niobium silicate and germanate open-framework structures. The organic template (piperazine) occupies a well-defined position at the intersection of the channels.
Why Pseudonyms? Deception as Identity Preservation Among Jazz Record Companies, 1920--1929

This paper theoretically and empirically engages the relationship between organizational identity and deception using the market for early jazz recordings as a setting. In this setting, pseudonyms (where a recording is reissued under a fictitious name) were used deceptively as a way to preserve a firm's identity while selling profitable but identity-threatening products to the mass market. Firms founded in the Victorian Era actively sought alignment with the cultural elite and used pseudonyms to deceive observers into believing that their production of cultural products was consistent with their Victorian Era identity. In effect, pseudonyms allowed these firms to decouple their position in identity space from their position in product space by inflating production of identity-preserving products. Using product data from jazz discographies, record company directories, and record advertisements in major U.S. newspapers, we provide strong empirical evidence that Victorian Era firms were active in using pseudonyms to preserve their identities.
Strained layer In/sub x/Ga/sub 1-x/As/GaAs and In/sub x/Ga/sub 1-x/As/In/sub y/Ga/sub 1-y/P multiple quantum well optical modulators grown by gas-source MBE

The first results on low power positive-intrinsic-negative (PIN) diode modulator structures using strained molecular beam epitaxy (MBE) on GaAs are presented. A comparison of transmission, reflection and photocurrent spectra for these nonresonant devices, with those fabricated from InGaAs/GaAs indicates larger modulation with a maximum change in reflection of >42% being observed at 5 V bias at a wavelength of 0.06 /spl mu/m. >
Engaging Law Enforcement in Overdose Reversal Initiatives: Authorization and Liability for Naloxone Administration

Opioid overdose is reversible through the timely administration of naloxone, which has been used by emergency medical services for decades. Law enforcement officers (LEOs) are often the first emergency responders to arrive at an overdose, but they are not typically equipped with naloxone. This is rapidly changing; more than 220 law enforcement agencies in 24 states now carry naloxone. However, rollout in some departments has been hampered by concerns regarding officer and agency liability. We systematically examined the legal risk associated with LEO naloxone administration. LEOs can be authorized to administer naloxone through a variety of mechanisms, and liability risks related to naloxone administration are similar to or lower than those of other activities in which LEOs commonly engage.
Computer-aided redesign of VLSI circuits for hot-carrier reliability

In this paper, a computer-aided design system for CMOS VLSI circuit hot-carrier reliability estimation and redesign is presented. The system first simulates a circuit to determine the critical transistors that are most susceptible to hot-carrier effects (HCEs). It then estimates the impact of HCE on circuit performance and employs a combination of design modification strategies to eliminate HCE-induced performance degradation. Two criteria are used to evaluate HCE degradation. The first criterion is the estimation of local damage in each transistor, which indicates the possibility of failure of individual devices. The second criterion is the global degradation of the circuit, namely the increase of delay in digital circuits. If either criterion exceeds a user-specified limit, several alternative circuit redesign strategies can be chosen by the user from a suggested menu. Based on this choice, the system will automatically redesign the critical parts of the circuit to improve circuit performance. The advantages and disadvantages of these alternative redesign strategies are also compared.
Supersymmetry and the AdS Higgs phenomenon

We examine the AdS Higgs phenomenon for spin-1 fields, and demonstrate that graviphotons pick up a dynamically generated mass in AdS4, once matter boundary conditions are relaxed. We perform an explicit one-loop calculation of the graviphoton mass, and compare this result with the mass generated for the graviton in AdS. In this manner, we obtain a condition for unbroken supersymmetry. With this condition, we examine both = 2 and = 4 gauged supergravities coupled to matter multiplets, and find that for both cases the ratio between dynamically generated graviton and graviphoton masses is consistent with unbroken supersymmetry.
Entering Adulthood in a Recession Tempers Later Narcissism

Despite widespread interest in narcissism, relatively little is known about the conditions that encourage or dampen it. Drawing on research showing that macroenvironmental conditions in emerging adulthood can leave a lasting imprint on attitudes and behaviors, I argue that people who enter adulthood during recessions are less likely to be narcissistic later in life than those who come of age in more prosperous times. Using large samples of American adults, Studies 1 and 2 showed that people who entered adulthood during worse economic times endorsed fewer narcissistic items as older adults. Study 3 extended these findings to a behavioral manifestation of narcissism: the relative pay of CEOs. CEOs who came of age in worse economic times paid themselves less relative to other top executives in their firms. These findings suggest that macroenvironmental experiences at a critical life stage can have lasting implications for how unique, special, and deserving people believe themselves to be.
Detections of Neutron Stars in the Extreme Ultraviolet

Neutron stars were not expected to be observable in the extreme ultraviolet and hence their detection in this band is a surprise. More important is that EUV observations provide unique new information on these objects. In the accompanying Table 1, I list the neutron stars detected in the EUV with the Extreme Ultraviolet Explorer ( EUVE ). The binary object Her X-l is the only object detected in the all sky survey. This is not surprising since it is the only neutron star system with sufficient intensity to be detectable in the 500 to 2000 second sky intergrations which are typical for the EUVE all sky survey. All the neutron stars were detected in the 100 A (Lexan) bandpass. A more complete description of EUVE and the all sky survey are provided in Bowyer and Malina (1991), and in Bowyer et al. (1994).
A technique for choosing zero locations for minimal overshoot

An approach is presented to the specification of optimal overshoot controllers when the controller order is fixed and the closed-loop system poles are at a fixed location. The essential effect of the technique is to pick the best possible locations of the free zeros of the system in terms of minimizing the overshoot. The solution is obtained by solving an affine minimax optimization problem. An example illustrates how this technique can be used as a design aid when it is necessary to trade off conflicting design requirements, such as overshoot and settling-time specifications. It is shown that the method is not restricted to the deadbeat case, but can also be used for any prescribed set of closed-loop poles. >
Analog active filters

This paper highlights major contributions, during the past half century, in the design of analog active networks with emphasis on active filters in the audiofrequency range. It is not possible to include the contributions of everyone in the field, the author, therefore, acknowledges and apologizes for the omission of the many noteworthy contributions not listed in this paper. Comprehensive lists of references are, however, available in the two IEEE edited books on active filters [1], [2]. John Linvill has summarized [3] the three decades of active networks, from the 1930's to the 1950's as follows: "The decade of the 1930's was one of tremendous strides in the synthesis of passive networks. The procedures established in that time are the backbone of the attack on many of today's designs of active networks, which frequently reduce to the appropriate synthesis of the passive parts of the system. The 1940's saw the full-scale development of the feedback system and the assessment of the limitations inherent in the parasitic elements that always accompany active components. The problem of realization of low-drift structures in the presence of drifting elements was attacked. The first encounter of the network theorist with elements that refuse to behave like a simple model brought new ideas and approaches. The 1950's were the decade of the transistor. The transistor, less capable of simple representation than its predecessors, offered new capabilities to reward the network designer. The physicist and the network theorist, each being more dependent on the other, have been drawn together. Many of the old problems have been resolved, without the earlier simplifying assumptions." The decade of the Sixties saw the emergence of the operational amplifier (op amp) as an off-the-shelf active element. The monolithic op amp introduced commercially in the late 1960's revived interest and stimulated much research work on active filters. The op amp is undoubtedly the most important linear circuit element to date. Sensitivity considerations also became an important research topic in its own right. During this decade a number of research papers also appeared in the area of distributed RC (\overline{RC}) networks, resulting in active- \overline{RC} filters (publications are listed in [4], 151). In the early to mid-1970's, the active- RC filter became a practical product with widespread use. In the late-1970's the switched-capacitor element came on the scene as a practical replacement for resistors in analog MOS integrated circuits. The partnership of MOS op amps and switched-capacitor networks accelerated work in active filters. The rapid development in the field and its compatibility with large scale integration (LSI) has made switched-capacitor filters one of the dominant technologies in active filters in the early-1980's and are expected to do so well into the 1980's.
Electrostatic probe measurements in solid- propellant rocket exhausts

A stagnation point electrostatic probe that can be used to measure local electrical characteristics of solid-propell ant rocket exhausts has been developed. The probe is a flat-faced insulated cylinder with the collector surface at the tip, and is water-cooled. The probe was tested in a laboratory flame and in small-scale rocket motor exhausts at the Naval Research Laboratory, and performed well both thermally and electrically. The analytical procedure for interpreting probe measurements was based on Lam's generalized continuum theory. The theory was verified in laboratory flames of known ionization levels. Positive ion and electron densities were measured in small-scale aluminized composite solid-propellant rocket motor exhausts at NRL. Tests in full-scale, sea-level rocket motor exhausts were performed, and positive ion densities in general agreement with theoretical predictions were obtained. It is concluded that local values of charged species concentrations in solid-propellant rocket motor exhausts can be obtained with a stagnation point electrostatic probe.
Rationality in the Joint Allocation of Private and Public Goods

In this study we assume that household demand for private and public goods are the e¢cient outcomes of the household decission process. From the efcient assumption we derive testable properties of these demands and we identify some characteristics of the intrahousehold distribution of the household expenditure. These results extend Chiappori (1988) main results to the case of joint consumption of private and public goods.
Literacy Instruction Using Technology with Primary-Age Culturally and Linguistically Diverse Learners.

With continuing advances in the digital world, a variety of technologies are becoming easily accessible in the classroom. Although teachers may be using some of these technologies in their daily lives, they may not know how to incorporate these devices to support classroom learning. This article provides a guide for teachers interested in using technology to deliver supplemental literacy instruction in their classroom, particularly for primary-age students from culturally and linguistically diverse backgrounds. Benefits of using technology along with classroom applications are discussed.
The Cosmological Constant from the Extended Theory of Gravitation in Clifford Spaces

The exploration of the novel physical consequences of the Extended Theory of Gravity in C-spaces (Clifford spaces) is continued. One of the most salient physical feature of the extended gravitational theory in C-spaces is that one can generate an effective stress energy tensor mimicking the effects of “dark” matter/energy. In particular, it is found that the presence of the cosmological constant, along with a plausible mechanism to explain its extremely small value and/or its cancellation, can be understood entirely from a purely Clifford algebraic and geometric perspective. For this reason we believe that this theory may have important consequences in Cosmology and further research in Gravitation and Particle Physics.
The Evolution of Skill-Biased Effects on American Wages in the 1980s and 1990s

This study estimates the contributions of skill-biased technological change and international trade to the rise in the skill premium during the 1980s and 90s using the Feenstra and Hanson (Q J Econ 114(3):907–940, 1999) two-stage methodology. Newly available data on high-technology capital provide separate measures of computer and software investment. New estimates suggest that investment in software contributed to a substantial portion of the observed increase in the skill premium while investment in computers lead to a reduction in the rate of skill premium growth. Contrary to the findings of Feenstra and Hanson for the 1980s, neither software nor computers had a significant effect on wages during the 1980s. Foreign outsourcing does not appear to have significantly affected wages during the 1990s. The contribution to theory is that software is more complementary to increases in worker productivity due to human skills. Computers, on the other hand, reduced the growth of wage inequality by giving unskilled labor a more efficient set of tools with which to work.
DARK STARS: A NEW LOOK AT THE FIRST STARS IN THE UNIVERSE

We have proposed that the first phase of stellar evolution in the history of the Universe may be Dark Stars (DS), powered by dark matter heating rather than by nuclear fusion, and in this paper we examine the history of these DS. The power source is annihilation of Weakly Interacting Massive Particles (WIMPs) which are their own antiparticles. These WIMPs are the best motivated dark matter (DM) candidates and may be discovered by ongoing direct or indirect detection searches (e.g. FERMI/GLAST) or at the Large Hadron Collider at CERN. A new stellar phase results, powered by DM annihilation as long as there is DM fuel, from millions to billions of years. We build up the dark stars from the time DM heating becomes the dominant power source, accreting more and more matter onto them. We have included many new effects in the current study, including a variety of particle masses and accretion rates, nuclear burning, feedback mechanisms, and possible repopulation of DM density due to capture. Remarkably, we find that in all these cases, we obtain the same result: the first stars are very large, 500-1000 times as massive as the Sun; as well as puffy (radii 1-10 A.U.), bright (10 6 − 10 7 L⊙), and cool (Tsurf 50,000K). Hence DS should be observationally distinct from standard Pop III stars. In addition, DS avoid the (unobserved) element enrichment produced by the standard first stars. Once the dark matter fuel is exhausted, the DS becomes a heavy main sequence star; these stars eventually collapse to form massive black holes that may provide seeds for the supermassive black holes observed at early times as well as explanations for recent ARCADE data (Seiffert et al. 2009) and for intermediate mass black holes. Subject headings: Dark Matter, Star Formation, Accretion
Laboratory experiments on stranding of Anopheles larvae under different shoreline environmental conditions

One of the concerns for future malaria epidemiology is the elevated risks of malaria around an ever-increasing number of dam sites. Controlling larval populations around reservoirs behind dams by manipulating the water levels of reservoirs could be an effective and sustainable measure for suppressing malaria epidemics; however, the effectiveness of the water-level manipulation and the contributing mechanisms have been poorly studied. In this paper, we focus on how water recession may lead to larval stranding. Larvae of An. albimanus were studied to assess their susceptibility to stranding under different conditions representing reservoir shoreline environments in an experimental tank (50 cm × 100 cm). The tank was initially seeded with 80 larvae uniformly, and the numbers of larvae stranded on land and remaining in water were counted (summed up to recovered larvae), following the recession of water. The vertical water drawdown rate and the proportion of stranded larvae to recovered larvae (p) were measured. Shoreline conditions tested were inclinations of shore slopes (2% and 4%) and surface types (smooth, vegetated, rough, ridged). For the 2% slopes, the proportions of stranded larvae (p) increased by about 0.002, 0.004, and 0.010 as the water drawdown rate increased by a centimeter per day on the smooth, rough, and vegetated surfaces, respectively. p for the 4% slopes were smaller than for the 2% slopes. Unlike other surface conditions, no significant correlation between p and the drawdown rate was observed on the ridged surface. Larger proportions of Anopheles larvae were stranded at higher water drawdown rates, on smaller reservoir slopes, and under rough or vegetated surface conditions. Three mechanisms of larval stranding were identified: falling behind shoreline recession; entrapment in small closed water bodies; and inhabitation in shallow areas. Depending on the local vectors of Anopheles mosquitoes, the conditions for their favorable breeding sites correspond to the conditions for large larval stranding. If these conditions are met, water-level manipulation could be an effective measure to control malaria along shorelines of reservoirs behind dams.
Property Rights and Theory of Value

This paper analyses and develops a conception of property rights and in turn makes possible the development of a new approach to the theory of value. As a result, the theory of value takes a more general form and the labor theory of value becomes one of special cases applicable to a primitive society only. Generally all three factors of production, namely the labor force, land, and capital, can create value, but only if there are property rights to them. This necessary condition has led us logically to a principle of relativity for property rights and, accordingly, value. Moreover, it is concluded that although capitalist economics considers practically everything as a commodity, there is, however, an exception – the labor force, which is only one that cannot be sold or bought.
Multi-Pixel Photon Counters for TOF PET Detector and Its Challenges

The Multi-Pixel Photon Counter (MPPC) is a Geiger-mode avalanche photo-diode (APD) developed by Hamamatsu Corp. We propose that it could be a suitable photo-sensor for next-generation time-of-flight PET detectors due to its high photon detection efficiency. We concentrate on the measurement of coincidence timing performance of various MPPCs in conjunction with LYSO crystal scintillators. With 3 mm times 3 mm devices of 50 mum sub-pixels coupled to 3 mm times 3 mm times 10 mm LYSO crystals, we have demonstrated a strong dependence of timing performance on over-voltage and temperature, and analyzed how changes in photon detection efficiency and dark counts would explain the measurements. The best coincidence timing resolution we have achieved between two identical LYSO/MPPC detectors was 240 ps in FWHM. This was worse than the timing resolution of 220 ps obtained with a Hamamatsu H6533 fast PMT, and contradicted the expected improvement from higher photon detection efficiency. The contradiction could be explained by the slow rise-time of MPPC pulse shape, transit time spread, dark counts and electronic noise from the large capacitance of the MPPC. In particular, the slow rise-time of the MPPC pulse suggests the need for a very low trigger threshold on the timing circuit. Since this makes the detector system more sensitive to noise, this poses additional challenges for ganging multiple devices together into a commercially viable time-of-flight PET block detector. We will discuss this work in detail including other challenge imposed by MPPC characteristics.
Adaptive line enhancement using a random AR model

The application of random autoregressive models to signal processing problems (specifically, to adaptive line enhancement) is discussed. The advantage of this approach is that random AR models may reflect more accurately the uncertainty in the stochastic process that generates the received signal. It is shown, through Monte Carlo simulations, that by using random AR models, better results are obtained than by using the conventional deterministic AR models under the same conditions. >
PATH INTEGRAL QUANTIZATION OF THE SYMPLECTIC LEAVES OF THE SU(2)* POISSON–LIE GROUP

The Feynman path integral is used to quantize the symplectic leaves of the Poisson–Lie group SU(2)*. In this way we obtain the unitary representations of ${\mathcal U}_q ({\rm su}(2))$. This is achieved by finding explicit Darboux coordinates and then using a phase space path integral. I discuss the *-structure of SU(2)* and give a detailed description of its leaves using various parametrizations. I also compare the results with the path integral quantization of spin.
Enantioselective and Enantiospecific Transition-Metal-Catalyzed Cross-Coupling Reactions of Organometallic Reagents To Construct C–C Bonds

The stereocontrolled construction of C−C bonds remains one of the foremost challenges in organic synthesis. At the heart of any chemical synthesis of a natural product or designed small molecule is the need to orchestrate a series of chemical reactions to prepare and functionalize a carbon framework. The advent of transition-metal catalysis has provided chemists with a broad range of new tools to forge C−C bonds and has resulted in a paradigm shift in synthetic strategy planning. The impact of these methods was recognized with the awarding of the 2010 Nobel Prize in Chemistry to Richard Heck, Ei-ichi Negishi, and Akira Suzuki for their seminal contributions to the development of Pd-catalyzed cross-coupling.
Millimeter-Wave Cellular Wireless Networks: Potentials and Challenges

Millimeter-wave (mmW) frequencies between 30 and 300 GHz are a new frontier for cellular communication that offers the promise of orders of magnitude greater bandwidths combined with further gains via beamforming and spatial multiplexing from multielement antenna arrays. This paper surveys measurements and capacity studies to assess this technology with a focus on small cell deployments in urban environments. The conclusions are extremely encouraging; measurements in New York City at 28 and 73 GHz demonstrate that, even in an urban canyon environment, significant non-line-of-sight (NLOS) outdoor, street-level coverage is possible up to approximately 200 m from a potential low-power microcell or picocell base station. In addition, based on statistical channel models from these measurements, it is shown that mmW systems can offer more than an order of magnitude increase in capacity over current state-of-the-art 4G cellular networks at current cell densities. Cellular systems, however, will need to be significantly redesigned to fully achieve these gains. Specifically, the requirement of highly directional and adaptive transmissions, directional isolation between links, and significant possibilities of outage have strong implications on multiple access, channel structure, synchronization, and receiver design. To address these challenges, the paper discusses how various technologies including adaptive beamforming, multihop relaying, heterogeneous network architectures, and carrier aggregation can be leveraged in the mmW context.
The class of tenable zero-balanced Pólya urn schemes: characterization and Gaussian phases

We study a class of tenable, irreducible, nondegenerate zero-balanced Polya urn schemes. We give a full characterization of the class by sufficient and necessary conditions. Only forms with a certain cyclic structure in their replacement matrix are admissible. The scheme has a steady state into proportions governed by the principal (left) eigenvector of the average replacement matrix. We study the gradual change for any such urn containing n → ∞ balls from the initial condition to the steady state. We look at the status of an urn starting with an asymptotically positive proportion of each color after j n draws. We identify three phases of j n : the growing sublinear, the linear, and the superlinear. In the growing sublinear phase the number of balls of different colors has an asymptotic joint multivariate normal distribution, with mean and covariance structure that are influenced by the initial conditions. In the linear phase a different multivariate normal distribution kicks in, in which the influence of the initial conditions is attenuated. The steady state is not a good approximation until a certain superlinear amount of time has elapsed. We give interpretations for how the results in different phases conjoin at the ‘seam lines’. In fact, these Gaussian phases are all manifestations of one master theorem. The results are obtained via multivariate martingale theory. We conclude with some illustrating examples.
Declining liver graft quality threatens the future of liver transplantation in the United States

National liver transplantation (LT) volume has declined since 2006, in part because of worsening donor organ quality. Trends that degrade organ quality are expected to continue over the next 2 decades. We used the United Network for Organ Sharing (UNOS) database to inform a 20-year discrete event simulation estimating LT volume from 2010 to 2030. Data to inform the model were obtained from deceased organ donors between 2000 and 2009. If donor liver utilization practices remain constant, utilization will fall from 78% to 44% by 2030, resulting in 2230 fewer LTs. If transplant centers increase their risk tolerance for marginal grafts, utilization would decrease to 48%. The institution of "opt-out" organ donation policies to increase the donor pool would still result in 1380 to 1866 fewer transplants. Ex vivo perfusion techniques that increase the use of marginal donor livers may stabilize LT volume. Otherwise, the number of LTs in the United States will decrease substantially over the next 15 years. In conclusion, the transplant community will need to accept inferior grafts and potentially worse posttransplant outcomes and/or develop new strategies for increasing organ donation and utilization in order to maintain the number of LTs at the current level.
Microprocessor-based sinusoidal waveform synthesis using Walsh and related orthogonal functions

A method is described of eliminating harmonics in a pulsewidth-modulated waveform using Walsh and related functions that substitute linear algebraic equations for the nonlinear equations required in Fourier-series harmonic elimination. A microprocessor can then be used to calculate the firing angles to cancel the unwanted harmonics. In an extension of the method, it is shown that a sine wave can be synthesized from a fixed-voltage DC supply by using a reasonable number of power electronic switches. >
On the Existence of Min-Max Minimal Torus

In this paper, we will study the existence problem of min-max minimal torus. We use classical conformal invariant geometric variational methods. We prove a theorem about the existence of min-max minimal torus in Theorem 5.1. First we prove a strong uniformization result (Proposition 3.1) using the method of Ahlfors and Bers (Ann. Math. 72(2):385–404, 1960). Then we use this proposition to choose good parameterization for our min-max sequences. We prove a compactification result (Lemma 4.1) similar to that of Colding and Minicozzi (Width and finite extinction time of Ricci flow, 0707.0108 [math.DG], 2007), and then give bubbling convergence results similar to that of Ding et al. (Invent. math. 165:225–242, 2006). In fact, we get an approximating result similar to the classical deformation lemma (Theorem 1.1).
An empirical comparison of software fault tolerance and fault elimination

The authors compared two major approaches to the improvement of software-software fault elimination and software fault tolerance-by examination of the fault detection (and tolerance, where applicable) of five techniques: run-time assertions, multiversion voting, functional testing augmented by structural testing, code reading by stepwise abstraction, and static data-flow analysis. The focus was on characterizing the sets of faults detected by the techniques and on characterizing the relationships between these sets of faults. Two categories of questions were investigated: (1) comparison between fault elimination and fault tolerance techniques and (2) comparisons among various testing techniques. The results provide information useful for making decisions about the allocation of project resources, show strengths and weaknesses of the techniques studies, and indicate directions for future research. >
The effects of E. coli 0157:H7, FMD and BSE on Japanese retail beef prices: A historical decomposition

This study examines the time-varying Japanese price reactions to the 2001 Bovine Spongiform Encephalopathy (BSE) discovery, the 2000 outbreak of foot and mouth disease (FMD), and the 1996 E. coli food po isoning events. Historical decomposition of retail -level price-series aids in explaining the behavior of beef prices in a neighborhood (period-by-period time interval) of the three events. This is based on an application of directed acyclic graphs, constructing orthogonal innovations to determine causal patterns behind contemporaneous innovations. The results show the beef safety events had different negative impacts on Japanese retail beef prices, suggesting that consumers understood and differentiated among the health risks. The results provide incentives for beef producers and retailers to proactively inform consumers about ongoing beef safety measures. Understanding consumer reaction to BSE, FMD and E. coli helps the beef industry restore consumer confidence after future food safety crises, and provides policy makers a basis for countermeasures and compensations. [EconLit citations: Q11, Q13.]
Bin completion algorithms for multicontainer packing, knapsack, and covering problems

Many combinatorial optimization problems such as the bin packing and multiple knapsack problems involve assigning a set of discrete objects to multiple containers. These problems can be used to model task and resource allocation problems in multi-agent systems and distributed systms, and can also be found as subproblems of scheduling problems. We propose bin completion, a branch-and-bound strategy for one-dimensional, multicontainer packing problems. Bin completion combines a bin-oriented search space with a powerful dominance criterion that enables us to prune much of the space. The performance of the basic bin completion framework can be enhanced by using a number of extensions, including nogood-based pruning techniques that allow further exploitation of the dominance criterion. Bin completion is applied to four problems: multiple knapsack, bin covering, min-cost covering, and bin packing. We show that our bin completion algorithms yield new, state-of-the-art results for the multiple knapsack, bin covering, and min-cost covering problems, outperforming previous algorithms by several orders of magnitude with respect to runtime on some classes of hard, random problem instances. For the bin packing problem, we demonstrate significant improvements compared to most previous results, but show that bin completion is not competitive with current state-of-the-art cutting-stock based approaches.
The Identifiability of Covarion Models in Phylogenetics

Covarion models of character evolution describe inhomogeneities in substitution processes through time. In phylogenetics, such models are used to describe changing functional constraints or selection regimes during the evolution of biological sequences. In this work the identifiability of such models for generic parameters on a known phylogenetic tree is established, provided the number of covarion classes does not exceed the size of the observable state space. `Generic parameters' as used here means all parameters except possibly those in a set of measure zero within the parameter space. Combined with earlier results, this implies both the tree and generic numerical parameters are identifiable if the number of classes is strictly smaller than the number of observable states.
Universal spectrum of 2d conformal field theory in the large c limit

Two-dimensional conformal eld theories exhibit a universal free energy in the high temperature limit T ! 1, and a universal spectrum in the Cardy regime, ! 1. We show that a much stronger form of universality holds in theories with a large central charge c and a sparse light spectrum. In these theories, the free energy is universal at all values of the temperature, and the microscopic spectrum matches the Cardy entropy for all c . The same is true of three-dimensional quantum gravity; therefore our results provide simple necessary and sucient criteria for 2d CFTs to behave holographically in terms of the leading spectrum and thermodynamics. We also discuss several applications to CFT and gravity, including operator dimension bounds derived from the modular bootstrap, universality in symmetric orbifolds, and the role of non-universal ‘enigma’ saddlepoints in the thermodynamics of 3d gravity.
Representing northern peatland microtopography and hydrology within the Community Land Model

Abstract. Predictive understanding of northern peatland hydrology is a necessary precursor to understanding the fate of massive carbon stores in these systems under the influence of present and future climate change. Current models have begun to address microtopographic controls on peatland hydrology, but none have included a prognostic calculation of peatland water table depth for a vegetated wetland, independent of prescribed regional water tables. We introduce here a new configuration of the Community Land Model (CLM) which includes a fully prognostic water table calculation for a vegetated peatland. Our structural and process changes to CLM focus on modifications needed to represent the hydrologic cycle of bogs environment with perched water tables, as well as distinct hydrologic dynamics and vegetation communities of the raised hummock and sunken hollow microtopography characteristic of peatland bogs. The modified model was parameterized and independently evaluated against observations from an ombrotrophic raised-dome bog in northern Minnesota (S1-Bog), the site for the Spruce and Peatland Responses Under Climatic and Environmental Change experiment (SPRUCE). Simulated water table levels compared well with site-level observations. The new model predicts hydrologic changes in response to planned warming at the SPRUCE site. At present, standing water is commonly observed in bog hollows after large rainfall events during the growing season, but simulations suggest a sharp decrease in water table levels due to increased evapotranspiration under the most extreme warming level, nearly eliminating the occurrence of standing water in the growing season. Simulated soil energy balance was strongly influenced by reduced winter snowpack under warming simulations, with the warming influence on soil temperature partly offset by the loss of insulating snowpack in early and late winter. The new model provides improved predictive capacity for seasonal hydrological dynamics in northern peatlands, and provides a useful foundation for investigation of northern peatland carbon exchange.
The real exchange rate, sectoral allocation and development in China and East Asia: A simple exposition

Global macroeconomic imbalances are among the key issues facing policymakers, especially in the US and China which are the two major affected / contributing parties. While there has been a great deal of discussion and disagreement on this important issue, what all sides have in common is the general failure to adequately pay attention to the role of the exchange rate in allocating resources internally between tradables and nontradables. These sectoral changes can have both real and macroeconomic consequences. This paper offers a simple analytical exposition of some of the issues relating to Chinas and East Asian development and their impact on global imbalances using a two-sector tradable and nontradables model.
Nonparametric Inference of Value-at-Risk for Dependent Financial Returns

The article considers nonparametric estimation of value-at-risk (VaR) and associated standard error estimation for dependent financial returns. Theoretical properties of the kernel VaR estimator are investigated in the context of dependence. The presence of dependence affects the variance of the VaR estimates and has to be taken into consideration in order to obtain adequate assessment of their variation. An estimation procedure of the standard errors is proposed based on kernel estimation of the spectral density of a derived series. The performance of the VaR estimators and the proposed standard error estimation procedure are evaluated by theoretical investigation, simulation of commonly used models for financial returns, and empirical studies on real financial return series.
A New Method for Enumerating Independent Sets of a Fixed Size in General Graphs

We develop a new method for enumerating independent sets of a fixed size in general graphs, and we use this method to show that a conjecture of Engbers and Galvin [7] holds for all but finitely many graphs. We also use our method to prove special cases of a conjecture of Kahn [13]. In addition, we show that our method is particularly useful for computing the number of independent sets of small sizes in general regular graphs and Moore graphs, and we argue that it can be used in many other cases when dealing with graphs that have numerous structural restrictions.
Auditing the Producer Price Index: Micro Evidence From Prescription Pharmaceutical Preparations

From January 1984 through December 1989, the Bureau of Labor Statistics (BLS) price index for prescription pharmaceuticals grew at 9.09% per year. Using BLS-type Laspeyres index procedures with monthly price and quantity data on all prescription pharmaceuticals sold by four U.S. pharmaceutical manufacturers accounting for 24% of industry domestic sales, we find that the four-company index increases at 6.68% per year. When we employ a Divisia price index with smoothed weights incorporating new goods, the index grows 6.03% per year. Why does the BLS index grow 50% more rapidly than the Divisia index? That mystery is the focal point of our article.
Finite state automata representing two-dimensional subshifts

A new type of two-dimensional automaton has been defined to recognize a class of two-dimensional shifts of finite type having the property that every admissible block found within the related local picture language can be extended to a point of the subshift. Here it is shown that this automaton accurately represents the image of the represented two-dimensional shift of finite type under a block code. It is then shown that these automata can be used to check for a certain type of two-dimensional transitivity in the factor language of the corresponding shift space and how this relates to periodicity in the two-dimensional case. The paper closes with a notion of ''follower sets'' that are used to reduce the size of the automata representing two-dimensional sofic shifts.
A sketch-based interface for iterative design and analysis of 3D objects

This paper presents a freehand, sketch-based interface for Computed Aided Design (CAD) engineering design and finite element analysis. After a user sketches a two dimensional sketch consisting of connected straight and curved strokes, the sketch is processed by two optimization-based reconstruction algorithms that can reconstruct sketches of 3D objects made up of straight lines and planar curves. The proposed implementation allows certain types of objects with over 50 strokes to be reconstructed in interactive time. Following reconstruction, the structural properties of the 3D shape can be examined using finite element analysis. The object can quickly be modified using the pen-based interface according to the results of the analysis. The combination of a rapid, sketch-based design interface and finite element analysis allows users to iteratively design, analyze and modify 3D objects in an intuitive and flexible way.
Interstellar scintillation of PSR J0437-4715 on two scales

Aims. We sought to determine the scale of scintillation in the interstellar plasma of PSR J0437 4715. Methods. We used the US VLB Array to obtain scintillation amplitude and phase data, from dynamic spectra at 327 MHz. Results. We observe two scales of scintillation of pulsar PSR J0437 4715, di ering by more than an order of magnitude in scintillation bandwidth. The wider-bandwidth scale of scintillation that we observe indicates less scattering for this pulsar than for other nearby pulsars, other than PSR B0950+08. The narrower scale agrees approximately with that observed for other nearby pulsars.
Enhancement of Solar Corona and Comet Details

Finely detailed striae in astronomical images can be important in formulation of theory. Examples are studies of streamers in the solar corona and of dust tails in comets. In both instances, conventional observations fail to reveal much of the structural detail. Digital image processing has been used at Los Alamos Scientific Laboratory (LASL) for enhancing these images. The corona images have tremendous variations in film density which must be eliminated before fine striae can be seen. These variations can be removed by means of numerical modeling of their spatial relation to the sun. This model can be thought of as a surface of background film density. In the comet images the overall variation is less severe. Further, the large number of comet images makes it infeasible to model them individually. Hence, an extreme low-pass filter was used to create an image which can be used as the background surface. In both cases, the background surface is divided into the original image pixel by pixel. This quotient image is then frequency-filtered for edge enhancement or noise control. Nonlinear density transformations are then used to enhance contrast. For both types of images, heretofore unmeasurable details become readily visible for analysis.