cssi/SciSciGPT-SciSciNet huggingface dataset:
Development of a high-throughput in vitro assay to identify selective inhibitors for human ALDH1A1

The human aldehyde dehydrogenase (ALDH) superfamily consists of at least 19 enzymes that metabolize endogenous and exogenous aldehydes. Currently, there are no commercially available inhibitors that target ALDH1A1 but have little to no effect on the structurally and functionally similar ALDH2. Here we present the first human ALDH1A1 structure, as the apo-enzyme and in complex with its cofactor NADH to a resolution of 1.75 and 2.1A, respectfully. Structural comparisons of the cofactor binding sites in ALDH1A1 with other closely related ALDH enzymes illustrate a high degree of similarity. In order to minimize discovery of compounds that inhibit both isoenzymes by interfering with their conserved cofactor binding sites, this study reports the use of an in vitro, NAD(+)-independent, esterase-based high-throughput screen (HTS) of 64,000 compounds to discover novel, selective inhibitors of ALDH1A1. We describe 256 hits that alter the esterase activity of ALDH1A1. The effects on aldehyde oxidation of 67 compounds were further analyzed, with 30 selectively inhibiting ALDH1A1 compared to ALDH2 and ALDH3A1. One compound inhibited ALDH1A1 and ALDH2, while another inhibited ALDH1A1, ALDH2, and the more distantly related ALDH3A1. The results presented here indicate that this in vitro enzyme activity screening protocol successfully identified ALDH1A1 inhibitors with a high degree of isoenzyme selectivity. The compounds identified via this screen plus the screening methodology itself represent a starting point for the development of highly potent and selective inhibitors of ALDH1A1 that may be utilized to better understand the role of this enzyme in both normal and disease states.
A worldwide system of reference rates

This paper assumes that the major industrial countries (and probably most other major countries) will continue to employ inflation targeting and allow their exchange rates to float, in the sense of accepting no obligation to hold the rate at any particular level. However, it points out that floating may be interpreted in three different ways: as free floating, as permitting ad hoc intervention (with no rules, except possibly that there should be no “manipulation” of the exchange rate), and as managed floating, with the rules and parameters publicly announced. The latter can in turn be accomplished either by prescribing rules relating to changes or levels in the exchange rate. The paper argues in favor of a system of managed floating in which the rules prohibit intervention that would push the exchange rate away from an internationally agreed reference rate. It discusses the problems that would arise in calculating and agreeing a set of reference rates. While these would undoubtedly be serious, the prize is a system that would allow—but not compel—countries to attempt to limit the misalignments of their currency, and that would give the IMF a basis for effective surveillance.
Kidneys From Deceased Donors: Maximizing the Value of a Scarce Resource

Donor age is a significant risk factor for graft loss after kidney transplantation. We investigated the question whether significant graft years were being lost through transplantation of younger donor kidneys into older recipients with potentially shorter lifespans than the organs they receive. We examined patient and graft survival for deceased donor kidney transplants performed in the United States between the years 1990 and 2002 by Kaplan-Meier plots. We categorized the distribution of deceased donor kidneys by donor and recipient age. Subsequently, we calculated the actual and projected graft survival of transplanted kidneys from younger donors with the patient survival of transplant recipients of varying ages. Over the study period, 16.4% (9250) transplants from donors aged 15-50 were transplanted to recipients over the age of 60. At the same time, 73.6% of donors above the age of 50 were allocated to recipients under the age of 60. The graft survival of grafts from younger donors significantly exceeded the patient survival of recipients over the age of 60. The overall projected improvement in graft survival, by excluding transplantation of younger kidneys to older recipients, was approximately 3 years per transplant. Avoiding the allocation of young donor kidneys to elderly recipients, could have significantly increased the overall graft life, by a total 27,500 graft years, between 1990 and 2002, with projected cost savings of about 1.5 billion dollars.
Durkheim as a Functionalist

Functionalism is basic to Durkheim's sociology. Like other functionalists, he focused on the problem of order and the positive effects of social institutions, explaining their existence in terms of their functionally necessary contributions. As a pioneer he grappled with many of the basic problems posed by this perspective. He derived more than one explanation linking existence and necessity. The most distinctive, and yet widely ignored, aspect of his approach is the implicit argument that as a powerful, self-conscious entity controlling the behavior of its individual members, society can perpetuate the social conditions of its own existence. Many of the characteristic strengths and weaknesses of Durkheim's sociological theory may be traced to his functionalism.
A high-performance microflowmeter with built-in self test

Abstract This paper reports the development of a high-performance readout scheme based on a switched-capacitor circuit and intended for use with an ultrasensitive microflowmeter. The microflow transducer improves significantly on the resolution of current flow devices and uses a differential capacitive pressure sensor to measure the flow. The readout electronics feature a clocking speed of 100 kHz and can drive loads as high as 35 pF. The high d.c. gain of the circuit topology (75 dB) is relatively insensitive to stray input capacitance and is ideally suited for a multichip sensor realization. The uncompensated linearity of the overall readout circuit is 10 bits and the pressure/flow resolution is 12 bits. Since ultrasensitive membranes respond to electrostatic forces, the output is characterized as a function of the duty cycle and pulse width of the readout clocking waveforms. The membrane does not respond to these waveforms for high frequencies ( > 50 kHz), but for lower frequencies the diaphragm deflects in response to the time-average voltage applied across the device. A self-test mode can therefore be implemented simply by changing the duty cycle of this pulse. By modifying the amplitude of the waveform, the device can be autocalibrated over a limited pressure range. The transducer and circuitry have been integrated into a flow package, and the multichip device has been tested versus a calibrated gas flow.
Parallel rectilinear shortest paths with rectangular obstacles

Abstract Atallah, M.J. and D.Z. Chen, Parallel rectilinear shortest paths with rectangular obstacles, Computational Geometry: Theory and Applications 1 (1991) 79-113. Given a rectilinear convex polygon P having O(n) vertices and which contains n pairwise disjoint rectangular rectilinear obstacles, we compute, in parallel, a data structure that supports queries about shortest rectilinear obstacle-avoiding paths in P. That is, a query specifies a source and a destination, and the data structure enables efficient processing of the query. We construct the data structure in O(log2n) time, with O(n2/log2n) processors in the CREW- PRAM model if all queries are such that the source and the destination are on the boundary of P, with O(n2/logn) processors if the source is an obstacle vertex and the destination is on the boundary of P, and with O(n2) processors if both the source and destination are arbitrary points in the plane. The data structure we compute enables one processor to obtain the path length for any pair of query vertices (of obstacles or of P) in constant time, or O(⌈k/logn⌉) processors to retrieve the shortest path itself in logarithmic time, where k is the number of segments of that path. If the two query points are arbitrary rather than vertices, then one processor takes O(logn) time (instead of constant time) for finding the path length, while the complexity bounds for reporting an actual shortest path remain unchanged. A number of other related shortest paths problems are solved. The techniques we use involve a fast computation of staircase separators, and a scheme for partitioning the obstacles' boundaries in a way that ensures that the resulting path length matrices have a monotonicity property that is apparently absent before applying our partitioning scheme. Sequentially, the data structure can be built in O(n2) time.
From wrapped M-branes to Calabi-Yau black holes and strings

We study a class of D = 11 BPS spacetimes that describe M-branes wrapping supersymmetric 2 and 4-cycles of Calabi-Yau 3-folds. We analyze the geometrical significance of the supersymmetry constraints and gauge field equations of motion for these spacetimes. We show that the dimensional reduction to D = 5 yields known BPS black hole and black string solutions of D = 5, N = 2 supergravity. The usual ansatz for the dimensional reduction is valid only in the linearized regime of slowly varying moduli and small gauge field strengths. Our identification of the massless D = 5 modes with D = 11 quantities extends beyond this regime and should prove useful in constructing non-linear ansatze for Calabi-Yau dimensional reductions of supergravity theories.
Photoproduction of pseudoscalar mesons

Abstract Experiments that study the photoproduction of pseudoscalar mesons; pions, etas and kaons, have the potential to increase our knowledge of baryon and hyperon resonance properties. Recent experiments at JLab, Mainz, GRAAL, and Bonn are beginning to produce results in the form of polarization and asymmetry measurements and determinations of the differential and integrated cross sections. These new data are essential to the performance of Partial-Wave Analyses that are less model dependent and coupled-channels calculations that incorporate unitarity dynamically, combining hadronic reaction channels together with electromagnetic processes. This approach is necessary to extract resonance properties and may lead to the identification of missing, but predicted, resonances. Some recent experimental and phenomenological results for single and double pseudoscalar meson photoproduction are discussed.
Computation of a Controlled Store Separation from a Cavity

Coupling of the Reynolds-averaged Navier-Stokes equations, rigid-body dynamics, and a pitch-attitude control law is demonstrated in two and three dimensions. The application problem was the separation of a canard-controlled store from an open-flow rectangular cavity at a freestream Mach number of 1.2. The transient flowfleld was computed using a diagonal scheme in an overset mesh framework, with the resultant aerodynamic loads used as the forcing functions in the nonlinear dynamics equations. The proportional and rate gyro sensitivities were computed via pole placement techniques for the linearized dynamical equations, in which computed aerodynamic stability derivatives were used. In two dimensions, a comparison between full and linearized flow equations for a perturbed pinned missile was made, and a controlled store was found to possess improved separation characteristics over a canard-fixed store. In three dimensions, trajectory comparisons with quasisteady wind-tunnel data for the canard-fixed case were made. Comparisons of canard-fixed and canardactive simulations showed that controlled store offers only modest improvements in cavity separation characteristics for these high-ejection rate cases.
Genesis and characterization of transition metal clusters in Y zeolites

Abstract Size and location of Pt particles in Y zeolites largely depend on the conditions of calcination following ion exchange. Besides destroying NH 3 ligands, calcination promotes migration of Pt ions from supercages to sodalite cages. The calcination temperature thus determines whether all, some, or none of the Pt ions remain in the supercages. In the first case, subsequent reduction results in small Pt clusters in supercages. Large Pt particles are, however, formed at the external surface, if all Pt ions were located in sodalite cages. If Pt ions are present in comparable quantities in both types of cages, those located in the supercages are reduced at low temperature and act as nucleation sites for the Pt atoms leaving the sodalite cages at higher temperature. By filling sodalite cages with auxiliary ions of other transition elements, the migration of Pt ions such cages can be suppressed; and a higher platinum dispersion is obtained after reduction.
Catalytic Enantioselective Synthesis of α-Aminooxy and α-Hydroxy Ketone Using Nitrosobenzene

The highly enantioselective and O-selective nitroso aldol reaction of tin enolates 2 and nitrosobenzene (1) has been developed with the use of (R)-BINAP−silver complexes as a catalyst. After the va...
Nanomesa and nanowell formations in Langmuir-Blodgett polyvinylidene fluoride trifluoroethelyne copolymer films

Crystalline nanomesa and nanowell formation has recently been discovered in polyvinylidene fluoride trifluoroethylene [P(VDF TrFE)] copolymer film, developed by Langmuir-Blodgett (LB) deposition. In this paper, a continuum field model is proposed to analyze this remarkable phenomenon, which is implemented in numerical simulations using finite difference method. Good agreement with experimental observations is observed.
SIMPLE SOLUTIONS TO THE EINSTEIN EQUATIONS IN SPACES WITH UNUSUAL TOPOLOGY

We discuss simple vacuum solutions to the Einstein Equations in five-dimensional space–times compactified in two different ways. In such spaces, one black hole phase and more than one black string phase may exist. Several old metrics are adapted to new background topologies to yield new solutions to the Einstein Equations. We then briefly talk about the angular momentum they may carry, the horizon topology and phase transitions that may occur.
Extension of the smith predictor

Abstract An effective means of controlling non-linear systems with time delays by use of a digital computer is presented. A model of the system is required, and an extension of Smith's method is used. The method is demonstrated on an experimental enzyme reactor containing a saturating element and a large delay relative to the time constants of the system. The time optimum control of the experimental system as well as PID control is used to demonstrate the effectiveness of the method.
The rise of vertical farms.

The article discusses the benefits to growing crops in city skyscrapers such as the reduction of water, fossil fuel consumption, and the elimination of agricultural runoff. The key concepts of the article is the impact of farming on the environment, the percentage of food a small block could yield with minimal use of resources, and how urban planners are incorporating the construction and use of vertical farms in cities worldwide. INSETS: Feeding the Future: Not Enough Land;GROWING TECHNIQUES.
TIRED TITANIUM: A FATIGUE‐BASED APPROACH TO AIRCRAFT INVENTORY MANAGEMENT AND ACQUISITION PLANNING

Airframe fatigue has emerged as a primary determinant of tactical aircraft service life. To investigate the impact of various operational scenarios on airframe fatigue and aircraft stocks, we develop an econometric model of fatigue and arrest landing accumulation for US Naval aircraft. Model forecasts suggest that fatigue‐related attrition threatens to reduce inventories below the level needed to meet operational commitments before planned replacements are available. Changes to training regimes could mitigate the shortfall, but it is likely that acquisition schedules will have to be accelerated, or current service life extension programs expanded to maintain inventories in the future. 1This research was conducted while Chad Meyerhoefer was an economist at The CNA Corporation and Robert Trost was at The CNA Corporation while on Summer Break from The George Washington University (GWU). No official endorsement by the Agency for Healthcare Research and Quality or the Department of Health and Human Services, b...
The surface science of graphene: Metal interfaces, CVD synthesis, nanoribbons, chemical modifications, and defects

Abstract Graphene, a single atomic layer of sp2 hybridized carbon, exhibits a zero-band gap with linear band dispersion at the Fermi-level, forming a Dirac-cone at the K -points of its Brillouin zone. In this review, we focus on basic materials science issues of this intriguing material. The scope of this work is further narrowed by concentrating on graphene grown at transition metal surfaces, mostly under vacuum conditions, and neglecting other graphene synthesis approaches, namely growth on SiC or by graphene oxide reduction. Thus one large section of this review focuses on metal/graphene interfaces. We summarize recent surface science studies on the structure, interaction, and the growth of graphene on various metals. Metal supported graphene is a recurring theme throughout this review as it provides model-systems for studying adsorption and graphene modifications on well-defined, large area samples, and thus is ideal for employing surface science techniques. Other aspects of graphene are also reviewed. Approaches for creating and characterizing graphene nanostructures, in particular graphene nanoribbons, are discussed. Graphene nanoribbons play an important role for potential electronic applications because the lateral electron confinement in the ribbons opens a band-gap in graphene. Materials issues of nanoribbons, like formation of well-defined edges are introduced. Atomic-scale defect-structures in graphene are another topic. The known defect structures in graphene are categorized and atomic scale characterization of these defects by scanning tunneling microscopy (stocktickerSTM) and high resolution transmission electron microscopy (TEM) is illustrated. Important for applications of graphene is our ability of modifying its properties. Therefore, studies of substitutional doping of graphene with nitrogen or boron, hydrogenation or fluorination of graphene, and the adsorption of molecules with strong electron affinity are included in this review. This review is restricted to a summary of surface science studies on well-ordered systems. Other important graphene research areas such as transport measurements on pure and modified graphene are not included. The goal of this review is to give a concise overview of the materials science of graphene from the surface science perspective.
Geoid anomalies in the vicinity of subduction zones

The regional geoid of the southwest Pacific is matched reasonably well by results from a model of the upper mantle density structure (including slabs) associated with subduction zones of the region. Estimates of the geoid are obtained from Geos-3 and Seasat radar altimeter data. These data are very well suited to the task of detecting intermediate wavelength (600-4000 km) geopotential variations. Actually, subducting slabs can be expected to produce primarily intermediate and longer wavelength variations. Gravimetric profiles across trench/island arc complexes resolve primarily short wavelengths. The model represents subducting slabs as thin surfaces of anomalous mass per unit area. These surfaces are positioned using published seismicity results which detail the configuration of the Benioff zones. Crustal effects are ignored. Effects due to the contrast between the young thermal lithosphere of the behind-arc regions (marginal basins) and the older lithosphere seaward of the trench are modelled. Results indicate that the New Hebrides slab possesses an average areal density anomaly of about 300,000 gm/sq cm. This is about three times that which is estimated for the Tonga-Kermadec slab. Additional modelling suggests that slabs worldwide may be an important source of large, long wavelength gravity highs; i.e., they may contribute substantially to geopotential power of harmonic degree as low as three or four up to twenty or more.
Medicare Balance Billing Restrictions: Impacts on Physicians and Beneficiaries

Beginning in the late 1980s, states and the federal government restricted the ability of physicians to "balance bill" Medicare beneficiaries for charges in excess of the copayment and reimbursement amounts approved by Medicare. In this paper, I provide empirical evidence that this policy change resulted in a 9% reduction in out-of-pocket medical expenditures by elderly households. In spite of the change in marginal reimbursement to physicians, however, I find little evidence that the restrictions affected patterns of care. Thus, this restriction on the prices charged by physicians amounted to a transfer from affected physicians to affected patients.
Effect of reactor loading on atomic oxygen concentration as measured by NO chemiluminescence

Summary It has previously been observed that the etch rate of polyethylene samples in the afterglow of an r.f. discharge in oxygen increases with reactor loading. This enhancement of the etch rate is attributed to reactive gas phase products of the polymer etching. In the present work, emission spectroscopy is employed to examine the species present in the gas phase during etching of polyethylene. In particular, the concentration of atomic oxygen downstream from the polyethylene samples is studied as a function of the reactor loading. It is found that the concentration of atomic oxygen increases as the reactor loading is increased. Since atomic oxygen is known to etch hydrocarbons, the increase of etch rate with increased reactor loading is attributed to the increase of atomic oxygen concentration in the vicinity of the sample.
Data augmentation for deep neural network acoustic modeling

This paper investigates data augmentation for deep neural network acoustic modeling based on label-preserving transformations to deal with data sparsity. Two data augmentation approaches, vocal tract length perturbation (VTLP) and stochastic feature mapping (SFM), are investigated for both deep neural networks (DNNs) and convolutional neural networks (CNNs). The approaches are focused on increasing speaker and speech variations of the limited training data such that the acoustic models trained with the augmented data are more robust to such variations. In addition, a two-stage data augmentation scheme based on a stacked architecture is proposed to combine VTLP and SFM as complementary approaches. Experiments are conducted on Assamese and Haitian Creole, two development languages of the IARPA Babel program, and improved performance on automatic speech recognition (ASR) and keyword search (KWS) is reported.
Between plan and market: The role of the local sector in post-mao China

Abstract The Chinese economy has long been characterized by multilevel planning, with local governments controlling nearly half of total industrial output and allocating substantial resources. Because of the important role played by local governments, market reforms have not brought a straight-forward transfer of decision-making authority from the central government to economic agents. Instead, there has been a good deal of “leakage” in the reform process, with local governments retaining and even expanding control over enterprises through a variety of informal mechanisms, as well as through their control over geographically immobile factor resources. This paper looks at the local sector and how market reforms have affected it.
Photoredox Activation for the Direct β-Arylation of Ketones and Aldehydes

The direct β-activation of saturated aldehydes and ketones has long been an elusive transformation. We found that photoredox catalysis in combination with organocatalysis can lead to the transient generation of 5π-electron β-enaminyl radicals from ketones and aldehydes that rapidly couple with cyano-substituted aryl rings at the carbonyl β-position. This mode of activation is suitable for a broad range of carbonyl β-functionalization reactions and is amenable to enantioselective catalysis.
A PRG for lipschitz functions of polynomials with applications to sparsest cut

We give improved pseudorandom generators (PRGs) for Lipschitz functions of low-degree polynomials over the hypercube. These are functions of the form ψ(P(x)), where P:{1,-1}n -> R is a low-degree polynomial and ψ:R -> R is a function with small Lipschitz constant. PRGs for smooth functions of low-degree polynomials have received a lot of attention recently and play an important role in constructing PRGs for the natural class of polynomial threshold functions [12,13,24,16,15]. In spite of the recent progress, no nontrivial PRGs were known for fooling Lipschitz functions of degree O(log n) polynomials even for constant error rate. In this work, we give the first such generator obtaining a seed-length of (log n)~O(l2/e2) for fooling degree l polynomials with error e. Previous generators had an exponential dependence on the degree l. We use our PRG to get better integrality gap instances for sparsest cut, a fundamental problem in graph theory with many applications in graph optimization. We give an instance of uniform sparsest cut for which a powerful semi-definite relaxation (SDP) first introduced by Goemans and Linial and studied in the seminal work of Arora, Rao and Vazirani [3] has an integrality gap of exp(Ω((log log n)1/2)). Understanding the performance of the Goemans-Linial SDP for uniform sparsest cut is an important open problem in approximation algorithms and metric embeddings. Our work gives a near-exponential improvement over previous lower bounds which achieved a gap of Ω(log log n) [11,21]. Our gap instance builds on the recent short code gadgets of Barak et al. [5].
Adenosine deaminase inhibitors. Synthesis and biological evaluation of aralkyladenines (ARADS).

Abstract Several 9-aralkyladenines have been prepared and their ADA inhibitory activity was determined. A minimum of two carbon atoms separating the aromatic ring from the adenine-bearing carbon (C3′) was found essential for potent activity.
Structure-Based Design and Synthesis of Substituted 2-Butanols as Nonpeptidic Inhibitors of HIV Protease: Secondary Amide Series

The design, synthesis, and crystallographic analysis of protein−inhibitor complexes is described for a novel series of nonpeptidic HIV protease (HIV Pr) inhibitors. Beginning with a cocrystal structure of a Phe-Pro peptidomimetic bound to the HIV Pr, design was initiated that resulted in the substituted 2-butanol compound 8 as the lead compound (Ki = 24.5 μM, racemic mixture). Modifications on the initial compound were then made on the basis of its cocrystal structure with HIV Pr and inhibition data, resulting in compounds with enhanced potency against the enzyme (compound 18, Ki = 0.48 μM). These inhibitors were found to bind to the enzyme essentially as predicted on the basis of the original design hypothesis. Stereospecific synthesis of individual enantiomers confirmed the prediction of a binding preference for the S alcohol stereochemistry. Modest antiviral activity was demonstrated for several of the more potent HIV Pr inhibitors in a HIV-1 infected CEM-SS cell line.
Synthesis and in vitro antitumor activity of some amino-deoxy 7-hexofuranosylpyrrolo[2,3-d]pyrimidines

Abstract 7-(6-amino-6-deoxy- β - d -glucofuranosyl)-5-cyanopyrrolo[2,3- d ]pyrimidine ( 22 ) and 7-(3-aminomethyl-3-deoxy- β - d -allofuranosyl)-5-cyanopyrrolo[2,3- d ]pyrimidine ( 28 ) were synthesized by sequentially coupling silylated 4-amino-6-bromo-5-cyanopyrrolo[2,3- d ]pyrimidine with the corresponding protected sugars 9 and 17 , followed by deblocking and catalytic hydrogenation. Conversion of the 5-nitrile in 22 and 28 into a carboxamide gave the corresponding sangivamycin derivatives 23 and 29 . Whereas 5′-aminomethyl nucleosides 22 and 23 inhibited the growth of four different human tumor cell lines at μ M concentrations, the 3′-aminomethyl analogs 28 and 29 were much less active against these cells.
Factorization theorems for high energy nn, $\gamma p$ and $\gamma\gamma$ scattering

The robustness of the factorization theorem for total cross sections, $\sigma_{nn}/\sigma_{\gamma p}=\sigma_{\gamma p}/\sigma_{\gamma\gamma}$ for nn (the even portion of pp and ${\bar p}p$ scattering), $\gamma p$ and $\gamma\gamma$ scattering, originally proved by Block and Kaidalov using an eikonal formalism, is demonstrated. Factorization theorems for the nuclear slope parameter B and $\rho$ , the ratio of the real to the imaginary portion of the forward scattering amplitude, are derived under very general conditions, using analyticity and the optical theorem.
WATER ABSORPTION FROM GAS VERY NEAR THE MASSIVE PROTOSTAR AFGL 2136 IRS 1

We present ground-based observations of the ν1 and ν3 fundamental bands of H2O toward the massive protostar AFGL 2136 IRS 1, identifying absorption features due to 47 different ro-vibrational transitions between 2.468 μm and 2.561 μm. Analysis of these features indicates the absorption arises in warm (T = 506 ± 25 K), very dense (n(H2) > 5 × 109 cm–3) gas, suggesting an origin close to the central protostar. The total column density of warm water is estimated to be N(H2O) = (1.02 ± 0.02) × 1019 cm–2, giving a relative abundance of N(H2O)/N(H2) 10–4. Our study represents the first extensive use of water vapor absorption lines in the near infrared, and demonstrates the utility of such observations in deriving physical parameters.
A short proof to the rigidity of volume entropy

In this note we give a short proof to the rigidity of volume entropy. The result says that for a closed manifold with Ricci curvature bounded from below, if the universal cover has maximal volume entropy, then it is the space form. This theorem was first proved by F. Ledrappier and X. Wang in [1].
Equilibrium cooperation in two-stage games: Experimental evidence*

This paper reports results of an experiment design ed to investigate the nature of cooperation and punishment. Subjects are matched in a series of two-person, two-stage games with a sequential equilibrium that supports first-stage cooperation with a credible threat of subsequent punishment. Participants sometimes used a consistent punish/reward strategy, and when they did, cooperation rates increased dramatically. The results thus contradict “payoff relevance”: second-stage behavior can be influenced by first-stage outcomes that have no effect on the payoff structure. Nevertheless, high cooperation rates were often not observed, even with a Pareto undominated “punishment” equilibrium in the second stage.
Can evolution explain how the mind works? A review of the evolutionary psychology debates

“Nothing in biology makes sense except in the light of evolution.” It would be hard to find a biologist today who disagrees with geneticist Theodosius Dobzhansky’s famous claim. Darwin’s theory of evolution via natural selection has done more than any other principle to explain the biological world, and to illuminate the relationships among all current life forms and among those found in the fossil record.
Selective heparinization of venous anastomosis in latissimus dorsi free flaps to cover lower-extremity soft-tissue defects

Two groups of consecutive patients treated with latissimus dorsi free myocutaneous flaps to cover lower-extremity soft-tissue defects were compared for postoperative vascular occlusion. In the first group of 13 patients (group I), there were five (38%) venous occlusions and no arterial occlusions. The second group of 15 patients (group II) was treated with selective heparinization of each venous anastomosis via a 0.35" catheter sutured into the serratus branch of the donor vein. In this group one patient suffered an arterial occlusion, but no patient suffered a venous occlusion. Statistical analysis using the Fisher exact probabilities test showed a significant decrease in vascular occlusion rate in group II, proving that selective heparinization had a beneficial effect on the venous patency rate.
PREMATURE MORTALITY AND POVERTY MEASUREMENT

There is a glaring paradox in all commonly used measures of poverty. The death of a poor person, because of poverty, reduces poverty according to these measures. This surely violates our basic intuitions of how poverty measures should behave. It cannot be right in concept that differentially higher mortality among the poor serves to reduce poverty. This article begins the task of developing poverty measures that are not perversely mortality sensitive. A family of measures is proposed that is an intuitive modification of standard poverty measures to take into account the fact that the rich live longer than the poor.
Genitourinary Complications of Crohn's Disease in Pediatric Patients

OBJECTIVE: The purpose of this study was to determine the incidence and types of genitourinary complications in pediatric patients with Crohn's disease. CONCLUSION: Genitourinary complications of Crohn's disease in children are not rare and may be the initial presentation of the condition.
MARKET SEGMENTATION STRATEGIES OF MULTIPRODUCT FIRMS

We analyze a multiproduct duopoly and ask whether firms should offer general purpose products or tailor their offerings to fit specific consumer needs. Offering a targeted product has two effects: utility increases for some consumers due to increased fit, whereas utility decreases for others due to increased misfit. Previous work has not considered these two effects jointly and has therefore not been able to capture the tradeoff inherent in market segmentation. We show that in addition to the degree of fit and misfit, the intensity of competition and the fixed cost of offering an additional product determine firms’ market segmentation strategies. EXTENDING PRODUCT LINES TO TARGET MORE NARROWLY DEFINED CONSUMER SEGMENTS has been a favorite strategy of brand managers for years. Popular buzzwords like one-on-one marketing and niche marketing underline its importance in practice. In this context, we ask to what extent market segmentation is justified from a profitability point of view. Consider a competitive environment in which each firm can either offer a general purpose product or segment the market by offering products that are tailored to consumers’ needs. While a consumer ceteris paribus prefers a product that is targeted at her own segment, she would rather buy a general purpose product than a product that is targeted at another segment. Segmenting the market therefore has two effects. First, if a consumer’s preferred product is offered, she is better off because she is able to buy a product that exactly fits her needs. We call this positive aspect of market segmentation fit. Second, if the consumer’s preferred product is not offered, she is worse off because she ends up with a product that does not satisfy her needs at all. This negative aspect of market segmentation is denoted as misfit.
OPTIMIZATION TECHNIQUES APPLIED TO IMPROVING FREEWAY OPERATIONS

Abstract This paper describes optimization techniques which have been developed and applied for evaluating freeway operational improvements such as redesign and/or ramp control strategies. The paper has four major parts. First, a deterministic macroscopic simulation model is described which predicts the traffic performance on a directional freeway as a function of freeway design and traffic demand patterns. Then two decision models are presented which automatically work with the simulation model to select optimum redesign and/or ramp control strategies. Finally, a freeway corridor model is described. Emphasis is given to the structure of the model and to the first step in the development of the freeway corridor model which is a major arterial street model.
Dynamic Investigation of DNA Bending and Wrapping By Type II Topoisomerases

Type II topoisomerases catalyze DNA decatenation and unwinding which is crucial for cell division, and therefore type II topoisomerases are some of the main targets of anti-cancer drugs. A recent crystal structure shows that, during the catalytic cycle, a yeast type II topoimerase can bend a 34 base pair DNA segment by up to 150 degrees. Bacterial gyrase, another type II topoisomerase, can wrap an approximately 100 bp DNA segment into a tight 180 degree turn. Bending a stiff polymer like DNA requires considerable energy and could represent the rate limiting step in the catalytic (topological) cycle. By substitututing diaminopurine (DAP) deoxyribonucleotides for dATP in PCR reactions, stiffer DNA fragments have been produced and used as substrates for topoisomerase II-mediated relaxation of plectonemes introduced in single molecules using magnetic tweezers. The overall rate of relaxation of plectonemes by recombinant human topoisomerase II alpha decreased on the stiffer DNA. In addition the ability of recombinant E. coli gyrase to wrap DNA also decreased for DAP-substituted DNA in which every base pair has three hydrogen bonds. These dynamic measurements of DNA bending and wrapping by type II topisomerases are consistent with the hypothesis that DNA flexibility affects the rate determining step for type II topoisomerase activity.
Bulgarian passports, Macedonian identity: The invention of EU citizenship in the Republic of Macedonia

: In this article, I examine some of the social effects that Bulgaria's EU membership has for Macedonia and the meanings that identification documents have for ethnic Macedonians who instrumentalize Bulgarian claims on their Macedonian identity for their own ends. I argue that the case study of Macedonia helps us view identification documents as objects that neither necessarily fix nationality nor are ineluctable guarantees of belonging to the (Bulgarian) nation-state, and understand state documentation practices as practices that do not always produce determined identities and citizen-subjects.
Why solve the Hamiltonian constraint in numerical relativity

The indefinite sign of the Hamiltonian constraint means that solutions to Einstein's equations must achieve a delicate balance – often among numerically large terms that nearly cancel. If numerical errors cause a violation of the Hamiltonian constraint, the failure of the delicate balance could lead to qualitatively wrong behavior rather than just decreased accuracy. This issue is different from instabilities caused by constraint-violating modes. Examples of stable numerical simulations of collapsing cosmological spacetimes exhibiting local mixmaster dynamics with and without Hamiltonian constraint enforcement are presented.
Anomalies in PT-Symmetric Quantum Field Theory

It is shown that a version of PT-symmetric electrodynamics based on an axial-vector current coupling massless fermions to the photon possesses anomalies and so is rendered nonrenormalizable. An alternative theory is proposed based on the conventional vector current constructed from massive Dirac fields, but in which the PT transformation properties of electromagnetic fields are reversed. Such a theory seems to possess many attractive features.
Climbing the Dispute Pagoda: Grievances and Appeals to the Official Justice System in Rural China

In the wake of heightened scholarly and media attention to the growing volume of conflict in rural China, this article represents the first effort to use survey data to identify the causes both of ...
Relationship of electric field and charged particle density fluctuations to air turbulence in the mesosphere

[1] A theoretical model is developed that is applicable to the electric field fluctuations that arise in the polar summer mesosphere as a result of the coupling of the charged species to the neutral air turbulence. The motions of electrons, ions, and charged aerosol particles are described as harmonic oscillators both driven and damped by the drag force exerted by the neutral air. The relative fluctuations in the ion density are found to be nearly the same as those in the neutral air as a consequence of the ions' high-momentum transfer relaxation frequency. The aerosol density fluctuations follow those of the neutral air at frequencies below their relaxation frequency, which is in the acoustic range. The electrons move primarily in response to the electric force to partially cancel the net charge density of ions and aerosol particles except at wavelengths shorter than the Debye length. Electric field and charge density fluctuations are calculated for several sets of conditions. In “bite-out” regions in which the electron density is reduced as a consequence of attachment to the aerosol particles the electric field fluctuations are found to be enhanced, which is consistent with observations.
Covariant Derivatives on Null Submanifolds

The degenerate nature of the metric on null hypersurfaces makes it difficult to define a covariant derivative on null submanifolds. Recent approaches using decomposition to define a covariant derivative on null hypersurfaces are investigated, with examples demonstrating the limitations of the methods. Motivated by Geroch’s work on asymptotically flat spacetimes, conformal transformations are used to construct a covariant derivative on null hypersurfaces, and a condition on the Ricci tensor is given to determine when this construction can be used. Several examples are given, including the construction of a covariant derivative operator for the class of spherically symmetric hypersurfaces.
In vivo colposcopic imaging of neoplastic tissues using optical coherence tomography

Summary form only given. In order to investigate the diagnostic utility of OCT for identifying markers of dysplastic change, an integrated OCT colposcope has been developed and used for clinical imaging. The integrated colposcope has a 300 mm long working distance and permits a simultaneous en face view of the cervix with real time OCT imaging. This design enables OCT images to be registered with the standard colposcopic view of cervical pathology. The OCT colposcope enables acquisition of cross-sectional tomographic images of cervical tissue. Images could be obtained with 15 /spl mu/m resolution at a rate of 4-8 frames per second for 500 and 250 transverse pixel images.
Message Delays with Prioritized HOLP and Round-Robin Packet Servicing

Three disciplines for prioritized transmission of messages in packet switching systems are considered. Messages from a finite number of classes having their lengths drawn independently from general service time distributions are assumed to arrive to the system according to independent Poisson processes. After entering the switch, the messages are divided into packets, overhead is added, and then the packets join a queue to be served according to one of the following disciplines: head-of-the-line (HOL), HOL with message preemption, and prioritized round robin (RR). Preemption of packet transmission is not allowed in any of the disciplines, and the service disciplines of different classes need not be the same. One result of the work presented here is a model to assess delays in the case of the prioritized RR; this work appears to be the first in which messages are not of fixed length and all quanta from a given message are served at the same priority. Numerical results which illustrate effects of choice of packet lengths and service disciplines upon delay of messages from the different classes are presented.
Total synthesis of lucilactaene, a cell cycle inhibitor active in p53-inactive cells.

Hetero-bis-metalated 1,3-butadiene is employed in the lynchpin coupling of synthetic fragments of the side chain of the antitumor agent, lucilactaene. Sequential Stille and Suzuki−Miyaura couplings interpolate this unique boron/tin diene into the pentaene chain. The total synthesis of lucilactaene was accomplished efficiently, in just eight linear steps.
Mixed Quinone Monoketals via Iodobenzene Diacetate Oxidation

Abstract Oxidation of p-methoxyphenol, 4-methoxynaphthol and 4-acetamidophenol with iodobenzenediacetate in various alcohols as solvent afforded the corresponding mixed quinone or naphthoquinone monoketals in good yield. Oxidation of p-methoxyphenol in the presence of sorbyl alcohol led to in situ intramolecular Diels-Alder reactions proceeding by way of the corresponding mixed quinone monoketal.
Template Removal and Thermal Stability of Organically Functionalized Mesoporous Silica Nanoparticles

The surfaces of organically functionalized, MCM-41-type mesoporous silica nanoparticle materials, prepared by a co-condensation method, were studied by solid-state nuclear magnetic resonance (NMR) spectroscopy following a series of heat treatments between 100 and 400 °C. The surfaces were functionalized with 2,2‘-bipyridine, 4-(dimethylamino)pyridine, and pentafluorobenzene. The 13C and 29Si NMR spectra of these materials showed that the structures and concentrations of these functional groups remained unaffected by the heat treatment. Furthermore, it has been demonstrated that the surfactant template, cetyltrimethylammonium bromide (CTAB), could be effectively removed from these materials by heat treatment without disrupting the covalent bonds between the functional groups and the silica surface. The chemical accessibility and reactivity of the organic functionalities were also preserved after heating.
Design and analysis of MAD transfer circuitry

This is the second in a series of papers concerned with a technique for performing combinatorial and sequential digital logic with magnetic elements and connecting wires only. These elements are termed MAD's (Multi-Aperture Devices). For clarity, in the first paper the basic techniques were described in terms of simple circuit structures which do not represent the best that can be achieved in the way of operational properties. The object of this paper is: 1) to present circuit techniques for significantly improving the circuit operation; and 2) to present experimental and analytic results which are pertinent to an understanding of the coupling loop operation.
Optimal software design reuse policies: A control theoretic approach

We study optimal policies for design reuse in a software project using a control theoretic approach. A project needs to be developed in minimum time by optimally choosing the proportion of effort allocated towards design activities. We first consider a local case, where the benefits of design activities are restricted within the project. Here the optimal policy follows a bang-bang structure: invest fully in design followed by investing fully in implementation. Next we consider two sequentially linked projects where design capital built in the first project can be reused by the downstream project. For the two project case, the design investment in the upstream project first increases and then decreases with the ability to utilize design capital accumulated in the first project for the second project. We also propose a coordination scheme that rewards the upstream project team so that design investment in this project is chosen in a globally optimal manner.
Two-photon absorption and self-phase modulation measurements with shaped femtosecond laser pulses

We demonstrate experimentally that phase sensitive detection of spectral hole refilling can yield information about self-phase modulation and two-photon absorption coefficients.
Tachyon condensates and string theoretic inflation

Abstract Cosmological solutions of the beta function equations for background fields of the closed bosonic string are investigated at the one-loop level. Following recent work of Kostelecky and Perry, it is assumed that the spatial sections of the space-time are conformally flat. Working in the sigma-model frame, the nontrivial tachyon potential is utilized to determine solutions with sufficient inflation to solve the smoothness and flatness problems. The graceful exit and density perturbation constraints can also be successfully implemented.
Chemistry of the Silicon-Silicon Double Bond

Disilenes, compounds containing silicon-silicon double bonds, can be isolated as thermally stable, yellow- or orange-colored crystalline compounds; the substituent groups at silicon must be large (mesityl, tert -butyl, etc.) to prevent polymerization. Structural and spectro-scopic studies indicate many similarities between the 3p–3p π bonding in disilenes and the 2p-2p π bonding in olefins, but disilenes are much more reactive than alkenes. The reactions of disilenes lead to many new classes of silicon compounds, including three- and four-membered rings which present novel problems in chemical bonding.