cssi/SciSciGPT-SciSciNet huggingface dataset:
Optimal Per-Use Rentals and Sales of Durable Products and Their Distinct Roles in Price Discrimination

We consider a setting in which consumers experience distinct instances of need for a durable product at random intervals. Each instance of need is associated with a random utility and the consumers are differentiated according to the frequency with which they experience such instances of need. We use our model of consumer utility to characterize the firm's optimal strategy of whether to sell, rent, or do a combination of both in terms of the transaction costs and consumers' usage characteristics. We find that the two modes of operation serve different roles in allowing the firm to price discriminate. While sales allow the firm to discriminate among consumers of different usage frequencies, rentals allow it to discriminate according to consumers' realized valuations. Consequently, even when transaction costs are negligible, it is often optimal for the firm to simultaneously rent and sell its product. In addition, we find that although sales and rentals are substitutes and that the offering of sales weakly increases rental prices, it is possible that the introduction of rentals to a pure selling operation can either increase or decrease the optimal sales prices
Suppression of base vibrations and tracking of the tip of an inverted pendulum using sliding mode control and quantitative feedback theory

AbstractThis paper presents a robust control method, combining sliding mode control (SMC) and quantitative feedback theory (QFT) to track the tip of an inverted pendulum, subject to base excitation. A non-linear inverted pendulum (IP) model is considered to analyse tracking control characteristics through computer simulation in order to demonstrate the effectiveness of the proposed control methodology. The sliding mode control is used to track the trajectory of the tip of the inverted pendulum. However, when the system enters into sliding regime, chattering occurs due to switching delays as well as base vibrations. The chattering is eliminated with the introduction of QFT inside the boundary layer to ensure smooth tracking. Problems with noise amplification, resonances, presence of uncertainties, and unmodelled high-frequency dynamics can largely be avoided with the use of QFT over other optimization methods. In addition, the QFT design methodology guides design evolution rather than replacing human inter...
Improved naïve Bayesian modeling of numerical data for absorption, distribution, metabolism and excretion (ADME) property prediction.

We have implemented a naive Bayesian classifier which models continuous numerical data using a Gaussian distribution. Several cases of interest in the area of absorption, distribution, metabolism, and excretion prediction are presented which demonstrate that this approach is superior to the implementation of naive Bayesian classifiers in which continuous chemical descriptors are modeled as binary data. We demonstrate that this enhanced performance, upon comparison with other implementations, is independent of the descriptor sets chosen. We also compare the performance of three implementations of naive Bayesian classifiers with other previously described models.
Evidence with uncertain likelihoods

An agent often has a number of hypotheses, and must choose among them based on observations, or outcomes of experiments. Each of these observations can be viewed as providing evidence for or against various hypotheses. All the attempts to formalize this intuition up to now have assumed that associated with each hypothesis h there is a likelihood function µh, which is a probability measure that intuitively describes how likely each observation is, conditional on h being the correct hypothesis. We consider an extension of this framework where there is uncertainty as to which of a number of likelihood functions is appropriate, and discuss how one formal approach to defining evidence, which views evidence as a function from priors to posteriors, can be generalized to accommodate this uncertainty.
Can the U.S. ethanol industry compete in the alternative fuels market

The U.S. ethanol fuel industry has experienced preferential treatment from federal and state governments ever since the Energy Tax Act of 1978 exempted 10% ethanol/gasoline blend (gasohol) from the federal excise tax. Combined with a 54c/ /gal ethanol import tariff, this exemption was designed to provide incentives for the establishment and development of a U.S. ethanol industry. Despite these tax exemptions, until recently, the U.S. ethanol fuel industry was unable to expand from a limited regional market. Ethanol was dominated in the market by MTBE (methyl-tertiary-butyl ether). Only after MTBE was found to contaminate groundwater and consequently banned in many states did the demand for ethanol expand nationally. Limit pricing on the part of MTBE refiners is one hypothesis that may explain this lack of ethanol entry into the fuel-additives market. As a test of this hypothesis, a structural vector autoregression (SVAR) model of the ethanol fuel market is developed. The results support the hypothesis of limit-pricing behavior on the part of MTBE refiners, and suggest the U.S. corn-based ethanol industry is vulnerable to limit-price competition, which could recur. The dependence of the corn-based ethanol price on supply determinants limits U.S. ethanol refiners' ability to price compete with sugar-cane-based ethanol refiners. Without federal support, U.S. ethanol refiners may find it difficult to compete with cheaper sugar-cane-refined ethanol, chiefly from Brazil.
The Effectiveness of the R&D Tax Credit: Evidence from the Alternative Simplified Credit

ABSTRACT: We examine the influence of the Alternative Simplified Credit (ASC) on firms' research and development (R&D) spending. The ASC remedies a perceived flaw with the previous R&D tax credit regime that excluded firms with high R&D intensities during their fixed-base periods and/or high sales in the previous four years from claiming a credit. We document a large increase in R&D tax credit eligibility following the enactment of the ASC, and find that its effect on R&D spending was positive relative to firms not utilizing this new credit-calculation option. Specifically, we estimate that the ASC induced an additional $2.26 of R&D spending for every dollar of forgone tax revenue. These results provide evidence that the ASC has spurred R&D investment in a setting where firms have a choice between two credit-calculation methods. JEL Classifications: H25, H32, O31
A system of medical error disclosure

External mandates for medical error disclosure are often justified by potential cost savings, the belief in individual moral obligations in health care, and the concept that patients have rights and providers have responsibilities. Such an approach does not recognise the systems nature of error and outcomes and the important quality role disclosure can play in a system of medical error disclosure. Systems concepts, the patient-provider partnership, and overall quality of care can be enhanced using a system of disclosure that provides for education about the systems nature of error, fulfils the delivery system philosophy of mutual respect, and integrates the patient and his/her family as a partner in the error reduction enterprise. Such a system can result using clear disclosure policies and procedures sensitive to patient and family needs, open communications with concerned, committed, and compassionate system representatives, and use of mediation methods that foster communication, allow for venting, and are flexible in their approach to resolving conflict, including using apology. Although a system may also result in conflict resolution costs, more importantly it may foster and solidify a team approach to reducing errors and promoting patient safety.
Japanese trading companies: can they be copied?

Analysis of Japanese trading companies suggests that would-be U.S. trading companies could be emulate Japan's special, rather than general, trading companies. Factors likely to lead to success are: offering narrow high-margin product lines in geographically diversified markets; integration with manufacturing operations having strong domestic markets; well capitalized finances with access to ample credit, perhaps achieved through partnership with large international banks; efficient working capital management consisting of liberal but controlled trade credit and tight inventories; management experienced in international markets and capable of heeding national interest considerations in many countries; and patience and a long-term outlook, since during client relationships are necessary to achieve profitability.
Capacity of a Multiple-Antenna Fading Channel With a Quantized Precoding Matrix

Given a multiple-input multiple-output (MIMO) channel, feedback from the receiver can be used to specify a transmit precoding matrix, which selectively activates the strongest channel modes. Here we analyze the performance of random vector quantization (RVQ), in which the precoding matrix is selected from a random codebook containing independent, isotropically distributed entries. We assume that channel elements are independent and identically distributed (i.i.d.) and known to the receiver, which relays the optimal (rate-maximizing) precoder codebook index to the transmitter using B bits. We first derive the large system capacity of beamforming (rank-one precoding matrix) as a function of B, where large system refers to the limit as B and the number of transmit and receive antennas all go to infinity with fixed ratios. RVQ for beamforming is asymptotically optimal, i.e., no other quantization scheme can achieve a larger asymptotic rate. We subsequently consider a precoding matrix with arbitrary rank, and approximate the asymptotic RVQ performance with optimal and linear receivers (matched filter and minimum mean squared error (MMSE)). Numerical examples show that these approximations accurately predict the performance of finite-size systems of interest. Given a target spectral efficiency, numerical examples show that the amount of feedback required by the linear MMSE receiver is only slightly more than that required by the optimal receiver, whereas the matched filter can require significantly more feedback.
Efficacy of dural tenting sutures.

Object. The goal of this study was to assess the necessity for the prophylactic use of dural tenting sutures. Methods. Data that had been prospectively collected from 369 consecutive cranial operations in adults were analyzed. In this series of patients, dural tenting sutures were used on a judicious “as needed” basis. They were never used to satisfy a procedural routine or for use as a prophylaxis against epidural hemorrhage that was not apparent. Tenting sutures were used for the control of epidural bleeding in 33 patients (8.9%); no tenting was required in 336 patients (91.1%). Reoperation for postoperative epidural hematoma was not required in this series. Conclusions. Dural tenting sutures continue to have an important role in neurosurgery; however, there is no compelling evidence to support their traditional prophylactic use in every intracranial operation.
THE IMPACT OF LIFE EXPECTANCY IN HUMAN CAPITAL ACCUMULATION: AIDS

A three period overlapping generations model is developed to investigate the impact of shorter life expectancy due to disease, on human capital investment decisions and income growth. This research is particularly relevant to Sub-Saharan Africa given the dramatic reduction in life expectancy due to HIV/AIDS and the potential lasting effects on growth. Our results indicate that as life expectancy shortens so does schooling inducing a lower growth rate of income. These relationships are even more pronounced for the African continent than for the rest of the world.
Conservatism of the gap metric

It is shown by way of simple examples that the gap metric may be inappropriate for quantifying the uncertainty for lightly damped systems, e.g. flexible structures such as spacecraft and aircraft. Two plants having otherwise identical transfer functions, except that their zeros on the imaginary axis are located slightly apart due to perturbations, are usually considered very close, i.e. their closed-loop characteristics under most stabilizing feedbacks are very similar. However, it is demonstrated that when the gap is used to quantify the plant perturbations, the computed gap may be large. Consequently, the stability of the perturbed plant with a stabilizing controller designed for the nominal plant cannot be guaranteed via the existing stability theorems using the gap metric. >
Effect of Coulomb collisions on time variations of the solar neutrino flux

We consider the processes that might suppress the time variations in the solar neutrino flux produced by the radial motion of the Earth through the neutrino interference pattern. We calculate these time variations and the extent to which they are suppressed by Coulomb collisions of the neutrino-emitting nuclei. This is done for both the 0.862-MeV 7Be neutrino line and the continuous neutrino spectrum, assuming a Gaussian energy response function of the neutrino detector. We find that the collisional decoherence averages out the time variations for neutrino masses A simple and clear physical picture of the time-dependent solar neutrino problem is presented and qualitative coherence criteria are discussed.
Mechanics of polarization ray tracing

Polarization ray tracing is a collection of methods that extends geometrical ray tracing allowing the calculation of the evolution of polarization states along ray paths and the determination of the intrinsic polarization properties, such as diattenuation and retardance, associated with ray paths. The suitability of the Jones, Mueller, and threedimensional polarization ray tracing calculi are compared, examining the issues of local versus global coordinates, amplitude versus phase representations, inclusion of the wavefront aberration function, partially polarized light, measurements of images by polarimeters, and diffraction image formation by low- and high-numerical-aperture beams.
CLOUD STRUCTURE AND PHYSICAL CONDITIONS IN STAR-FORMING REGIONS FROM OPTICAL OBSERVATIONS. II. ANALYSIS

To complement the optical absorption line survey of diffuse molecular gas in Paper I, we obtained and analyzed far-ultraviolet H2 and CO data on lines of sight toward stars in Cep OB2 and Cep OB3. Possible correlations between column densities of different species for individual velocity components, not total columns along a line of sight as in the past, were examined and were interpreted in terms of cloud structure. The analysis reveals that there are two kinds of CH in diffuse molecular gas: CN-like CH and CH+-like CH. Evidence is provided that CO is also associated with CN in diffuse molecular clouds. Different species are distributed according to gas density in the diffuse molecular gas. Both calcium and potassium may be depleted onto grains in high-density gas, but with different dependencies on local gas density. Gas densities for components where CN was detected were inferred from a chemical model. Analysis of cloud structure indicates that our data are generally consistent with the large-scale structure suggested by maps of CO millimeter-wave emission. On small scales, the gas density is seen to vary by factors greater than 5.0 over scales of ~10,000 AU. The relationships between column densities of CO and CH with that of H2 along a line of sight show similar slopes for the gas toward Cep OB2 and Cep OB3, but the CO/H2 and CH/H2 ratios tend to differ, which we ascribe to variation in average density along the line of sight.
High-intensity ultrasound-promoted reformatsky reactions.

Reformatsky reactions of a phenyl ketone, an α-bromoester, zinc dust, and a catalytic amount of iodine in dioxane under high-intensity ultrasound (HIU) irradiation from an ultrasonic probe give high yields of β-hydroxyesters in short reaction times. A series of alkyl phenyl ketones with increasing steric demands of the alkyl group are evaluated as potential electrophiles for the reactions with several α-bromoesters, also having increasing steric demands. The Reformatsky reaction under HIU is found to be concentration dependent.
A Mechanism for Communication-Efficient Broadcast Encryption over Wireless Ad Hoc Networks

Due to its low communication cost, stateful broadcast encryption is an appealing solution for secure content distribution in mobile ad hoc wireless networks (MANETs). Unfortunately, the inherent limitations of MANETs prevent a standard application of such schemes since they require receivers to be online. In this paper, we present a reliable message delivery mechanism for MANETs that is based on erasure codes and that leverages node mobility in order to achieve non-interactive recovery of missed messages. We then show how our mechanism can be used to reliably deliver the key updates of a stateful broadcast encryption scheme. Our solution has several useful properties: it allows trade-offs between the amount of storage required at each node and the speed of message recovery; and it has the ability to leverage the resources of unauthorized nodes. We evaluate the performance of our approach through simulation, and show that it achieves good performance for networks with high node density.
A quantitative measure, mechanism and attractor for self-organization in networked complex systems

Quantity of organization in complex networks here is measured as the inverse of the average sum of physical actions of all elements per unit motion multiplied by the Planck's constant. The meaning of quantity of organization is the number of quanta of action per one unit motion of an element. This definition can be applied to the organization of any complex system. Systems self-organize to decrease the average action per element per unit motion. This lowest action state is the attractor for the continuous self-organization and evolution of a dynamical complex system. Constraints increase this average action and constraint minimization by the elements is a basic mechanism for action minimization. Increase of quantity of elements in a network, leads to faster constraint minimization through grouping, decrease of average action per element and motion and therefore accelerated rate of self-organization. Progressive development, as self-organization, is a process of minimization of action.
Can iterative decoding for erasure correlated sources be universal

In this paper, we consider a few iterative decoding schemes for the joint source-channel coding of correlated sources. Specifically, we consider the joint source-channel coding of two erasure correlated sources with transmission over different erasure channels. Our main interest is in determining whether or not various code ensembles can achieve the capacity region universally over varying channel conditions. We consider two ensembles in the class of low-density generator-matrix (LDGM) codes known as Luby-Transform (LT) codes and one ensemble of low-density parity-check (LDPC) codes. We analyze them using density evolution and show that optimized LT codes can achieve the extremal symmetric point of the capacity region. We also show that LT codes are not universal under iterative decoding for this problem because they cannot simultaneously achieve the extremal symmetric point and a corner point of the capacity region. The sub-universality of iterative decoding is characterized by studying the density evolution for LT codes.
Reformulating the map color theorem

This paper discusses reformulations of the problem of coloring plane maps with four colors. We include discussion of the Eliahou-Kryuchkov conjecture, the Penrose formula, the vector cross-product formulation and the reformulations in terms of formations and factorizations due to G. Spencer-Brown.
Mismatched Estimation and Relative Entropy

A random variable with distribution P is observed in Gaussian noise and is estimated by a mismatched minimum mean-square estimator that assumes that the distribution is Q, instead of P . This paper shows that the integral over all signal-to-noise ratios (SNRs) of the excess mean-square estimation error incurred by the mismatched estimator is twice the relative entropy D(P ||Q) (in nats). This representation of relative entropy can be generalized to nonreal-valued random variables, and can be particularized to give new general representations of mutual information in terms of conditional means. Inspired by the new representation, we also propose a definition of free relative entropy which fills a gap in, and is consistent with, the literature on free probability.
Minimax Robust Quickest Change Detection

The popular criteria of optimality for quickest change detection procedures are the Lorden criterion, the Pollak criterion, and the Bayesian criterion. In this paper, a robust version of these quickest change detection problems is considered when the pre-change and post-change distributions are not known exactly but belong to known uncertainty classes of distributions. For uncertainty classes that satisfy a specific condition, it is shown that one can identify least favorable distributions (LFDs) from the uncertainty classes, such that the detection rule designed for the LFDs is optimal for the robust problem in a minimax sense. The condition is similar to that required for the identification of LFDs for the robust hypothesis testing problem originally studied by Huber. An upper bound on the delay incurred by the robust test is also obtained in the asymptotic setting under the Lorden criterion of optimality. This bound quantifies the delay penalty incurred to guarantee robustness. When the LFDs can be identified, the proposed test is easier to implement than the CUSUM test based on the Generalized Likelihood Ratio (GLR) statistic which is a popular approach for such robust change detection problems. The proposed test is also shown to give better performance than the GLR test in simulations for some parameter values.
On the Effective Capacity of Two-Hop Communication Systems

In this paper, two-hop communication between a source and a destination with the aid of an intermediate relay node is considered. Both the source and intermediate relay node are assumed to operate under statistical quality of service (QoS) constraints imposed as limitations on the buffer overflow probabilities. It is further assumed that the nodes send the information at fixed power levels and have perfect channel side information. In this scenario, the maximum constant arrival rates that can be supported by this two-hop link are characterized by finding the effective capacity. Through this analysis, the impact upon the throughput of having buffer constraints at the source and intermediate-hop nodes is identified.
Infinite class field towers

This paper studies infinite class field towers of number fields K that are ramified over \({\mathbb{Q}}\) only at one finite prime. In particular, we show the existence of such towers for a general family of primes including p = 2, 3 and 5.
Face Detection in the Near-IR Spectrum

Abstract Face detection is an important prerequisite step for successful face recognition. The performance of previous face detection methods reported in the literature is far from perfect and deteriorates ungracefully where lighting conditions cannot be controlled. We propose a method that outperforms state-of-the-art face detection methods in environments with stable lighting. In addition, our method can potentially perform well in environments with variable lighting conditions. The approach capitalizes upon our near-IR skin detection method reported elsewhere [Proceedings IEEE Workshop on Computer Vision beyond the Visible Spectrum: Methods and Applications; 2000, IEEE Trans. Int. Trans. Sys.; vol. 1; 72–85]. It ascertains the existence of a face within the skin region by finding the eyes and eyebrows. The eye–eyebrow pairs are determined by extracting appropriate features from multiple near-IR bands. Very successful feature extraction is achieved by simple algorithmic means like integral projections and template matching. This is because processing is constrained in the skin region and aided by the near-IR phenomenology. The effectiveness of our method is substantiated by comparative experimental results with the Identix face detector [ http://www.faceit.com ].
On the capture probability for a large number of stations

The probability of capture under a model (for a land mobile radio direct sequence spread spectrum system) based on the ratio of the largest received power to the sum of interference powers is examined in the limit of a large number of transmitting stations. It is shown in great generality that the limit depends only on the capture ratio threshold and the roll-off exponent of the distribution of power received from a typical station. This exponent is insensitive to many typical channel effects such as Rician or Rayleigh fading and log-normal shadowing. The model is suitable for large systems with noncoherently combined interference.
Dynamics of a quantum reference frame

We analyse a quantum mechanical gyroscope which is modelled as a large spin and used as a reference against which to measure the angular momenta of spin-1/2 particles. These measurements induce a back-action on the reference which is the central focus of our study. We begin by deriving explicit expressions for the quantum channel representing the back-action. Then, we analyse the dynamics incurred by the reference when it is used to sequentially measure particles drawn from a fixed ensemble. We prove that the reference thermalizes with the measured particles and find that generically, the thermal state is reached in a time which scales linearly with the size of the reference. This contrasts with a recent conclusion of Bartlett et al that this takes a quadratic amount of time when the particles are completely unpolarized. We now understand their result in terms of a simple physical principle based on symmetries and conservation laws. Finally, we initiate the study of the non-equilibrium dynamics of the reference. Here we find that a reference in a coherent state will essentially remain in one when measuring polarized particles, while rotating itself to ultimately align with the polarization of the particles.
Performance analysis of non-coherent UWB receivers at different synchronization levels

Non-coherent ultra-wideband (UWB) receivers require no channel state information for demodulating the received signal. The primary non-coherent receiver in the UWB literature is the autocorrelation receiver, which autocorrelates the received signal at specific time lags, circumventing problems of template signal design and multipath energy combining. A unique advantage of the UWB autocorrelation receiver is its robustness to synchronization errors, which has not been explored yet to date. This paper investigates two major UWB schemes employing autocorrelation receivers: the transmitted reference (TR) scheme (R. Hoctor and H. Tomlinson, 2002) and the differential (DF) scheme (M. Ho et al., 2002). Performance is analyzed for TR and DF receivers at different synchronization accuracy levels, their robustness to synchronization errors is shown, and the existence of a tradeoff between performance and synchronization complexity for non-coherent UWB receivers is revealed. As a result of our analysis, comparisons of TR and DF schemes are also made in the presence of synchronization errors, which have not been addressed before. Simulations corroborate our findings
The synthesis and chemistry of certain anthelmintic benzimidazoles

A basis for interest in the benzimidazole ring system as a nucleus from which to develop potential chemotherapeutic agents was established in the 1950s when it was found that 5,6-dimethyl-l-(alpha-D-ribofuranosyl)benzimidazole (I) was an integral part of the [structure: see text] structure of vitamin B(12). As a result of these interests and extensive studies, one health related arena that has benefited greatly has been the treatment of parasitic diseases. The discovery of thiabendazole in 1961 further spurred chemists around the world to design and synthesize several thousand benzimidazoles for screening for anthelmintic activity but less than twenty of them have reached commercial use. Much of this work has been done by pharmaceutical companies and is only reported in the patent literature. In this paper, Leroy Townsend and Dean Wise review the development of some of the synthetic methods that have been critical to the preparation of the benzimidazoles of anthelmintic importance. Only a few molecules that demonstrate the processes are discussed here, but numerous reviews of the synthesis and chemistry of other benzimidazoles are available.
A Note on How and Why Growth and Unemployment Go Hand in Hand in Developing Economies

AbstractThis paper develops a simple model to explain the phenomenon of persistent unemployment, even in an economy experiencing high output growth. In the model, unemployment grows at a rate identical with the growth rate of input factors and sectors. The result is primarily triggered by a pre-fixed minimum wage for unskilled workers. To corroborate our claim, we have empirically tested our model hypothesis using data for 12 developing countries and found empirical results consistent with the theory. To mitigate or reduce unemployment, history becomes crucial in deciding on the desired rate of growth in different sectors.
Chern-Simons gauge theory as a string theory

Certain two dimensional topological field theories can be interpreted as string theory backgrounds in which the usual decoupling of ghosts and matter does not hold. Like ordinary string models, these can sometimes be given space-time interpretations. For instance, three-dimensional Chern-Simons gauge theory can arise as a string theory. The world-sheet model in this case involves a limiting case of Floer/Gromov theory of symplectic manifolds. The instantons usually considered in Floer theory give rise to Wilson line insertions in the space-time Chern-Simons theory. A certain holomorphic analog of Chern-Simons theory can also arise as a string theory.
Magnetic pair creation transparency in gamma-ray pulsars

Magnetic pair creation, γ → e {sup +} e {sup –}, has been at the core of radio pulsar paradigms and central to polar cap models of gamma-ray pulsars for over three decades. The Fermi gamma-ray pulsar population now exceeds 140 sources and has defined an important part of Fermi's science legacy, providing rich information for the interpretation of young energetic pulsars and old millisecond pulsars. Among the population characteristics well established is the common occurrence of exponential turnovers in their spectra in the 1-10 GeV range. These turnovers are too gradual to arise from magnetic pair creation in the strong magnetic fields of pulsar inner magnetospheres. By demanding insignificant photon attenuation precipitated by such single-photon pair creation, the energies of these turnovers for Fermi pulsars can be used to compute lower bounds for the typical altitude of GeV band emission. This paper explores such pair transparency constraints below the turnover energy and updates earlier altitude bound determinations that have been deployed in various Fermi pulsar papers. For low altitude emission locales, general relativistic influences are found to be important, increasing cumulative opacity, shortening the photon attenuation lengths, and also reducing the maximum energy that permits escape of photons frommore » a neutron star magnetosphere. Rotational aberration influences are also explored, and are found to be small at low altitudes, except near the magnetic pole. The analysis presented in this paper clearly demonstrates that including near-threshold physics in the pair creation rate is essential to deriving accurate attenuation lengths and escape energies. The altitude bounds are typically in the range of 2-7 stellar radii for the young Fermi pulsar population, and provide key information on the emission altitude in radio quiet pulsars that do not possess double-peaked pulse profiles. The bound for the Crab pulsar is at a much higher altitude, with the putative detection by MAGIC out to 350-400 GeV implying a lower bound of 310 km to the emission region, i.e., approximately 20% of the light cylinder radius. These results are also extended to the super-critical field domain, where it is found that emission in neurton stars originating below around 10 stellar radii will not appear in the Fermi-LAT band.« less
Synthesis of biologically active N2-amine adducts of 2′-deoxyguanosine

Abstract Several biologically important N2-adducts of 2′-deoxyguanosine (dG) that previously were difficultly accessible, have been synthesized directly by means of the Buchwald–Hartwig reaction. The reaction employed in each case involves the coupling of 2′-deoxy-2-bromoinosine with the appropriate amine. Deprotection in all cases gave good yields of the desired 2-alkylated or -arylated deoxynucleoside.
Expert systems for power system control in Western Europe

Research and development activities of West European utilities, manufacturers, and research institutions in the domain of expert system applications for power system control are surveyed. The development of 12 expert system applications in different project states from prototype to practical use in an electric utility is studied. To get information on the present state of these projects, 13 research institutions, manufacturers, and utilities were asked to fill out a questionnaire. The answers to the questionnaire, which was filled out by 10 institutions, and the comments by the developers are briefly cited and summarized. >
Dehydrogenative silation, isomerization and the control of syn- vs. anti-addition in the hydrosilation of alkynes

Abstract Alkyne hydrosilation has been examined in detail for the catalysts [IrH(H 2 O)(bq)L 2 ]SbF 6 (L = PPh 3 , bq = 7,8-benzoquinolinato) and RhCl(PPh 3 ) 3 . Factors that favor the normal syn - or the unusual anti -silane addition to the alkynes are examined. Two other unusual products are noted: the dehydrogenative silation product RCCSiR 3 , formed by β-elimination in a vinylmetal intermediate and allylsilane products of vinylsilane isomerization. The iridium catalyst is advantageous in that it does not give fast vinylsilane isomerization, as does RhCl(PPh 3 ) 3 , so allowing formation and isolation of the thermodynamically less stable cis -, rather than the more stable trans -vinylsilane isomer RCHCH(SiR' 3 ).
Excitonic couplings and electronic coherence in bridged naphthalene dimers

The electronic excitations of naphthalene and a family of bridged naphthalene dimers are calculated and analyzed by using the Collective Electronic Oscillator method combined with the oblique Lanczos algorithm. All experimentally observed trends in absorption profiles and radiative lifetimes are reproduced. Each electronic excitation is linked to the corresponding real-space transition density matrix, which represents the motions of electrons and holes created in the molecule by photon absorption. Two-dimensional plots of these matrices help visualize the degree of exciton localization and explain the dependence of the electronic interaction between chromophores on their separation.
Growth of GaN on porous SiC and GaN substrates

GaN films were grown on porous SiC and GaN templates using both plasma-assisted molecular beam epitaxy (PAMBE) and metal-organic chemical vapor deposition (MOCVD) to evaluate possible advantage of epitaxy on a porous substrate. For the growth of GaN on porous SiC by PAMBE, transmission electron microscopy (TEM) observations indicate that the exposed SiC suface pores tend to extend into the GaN film as open tubes and to trap Ga droplets. The GaN layers grown on porous templates have fewer threading dislocations originating at the interface, but they have additional defects in the form of half-loop dislocations which act to relieve the strain in the films. For PAMBE of GaN on porous GaN, dislocations existing in the porous seed layer are seen to propagate through the porous layer into the overgrown GaN, resulting in no dislocation reduction. For MOCVD of GaN on porous GaN, the initial regrowth tend to bend laterally the dislocations and enhance their annihilation, resulting in 5–10 × fewer dislocations in the overgrown film. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
The Two-Edge Connectivity Survivable-Network Design Problem in Planar Graphs

Consider the following problem: given a graph with edge costs and a subset Q of vertices, find a minimum-cost subgraph in which there are two edge-disjoint paths connecting every pair of vertices in Q. The problem is a failure-resilient analog of the Steiner tree problem arising, for example, in telecommunications applications. We study a more general mixed-connectivity formulation, also employed in telecommunications optimization. Given a number (or requirement) r(v) ∈ l0, 1, 2r for each vertex v in the graph, find a minimum-cost subgraph in which there are min lr(u), r(v)r edge-disjoint u-to-v paths for every pair u, v of vertices.We address the problem in planar graphs, considering a popular relaxation in which the solution is allowed to use multiple copies of the input-graph edges (paying separately for each copy). The problem is max SNP-hard in general graphs and strongly NP-hard in planar graphs. We give the first polynomial-time approximation scheme in planar graphs. The running time is O(nlog n).Under the additional restriction that the requirements are only non-zero for vertices on the boundary of a single face of a planar graph, we give a polynomial-time algorithm to find the optimal solution.
Music for a Song: An Empirical Look at Uniform Song Pricing and its Alternatives

Economists have well-developed pricing theories that challenge the wisdom of the common practice of uniform song pricing. This paper explores the profit and welfare implications of various alternatives, including song-specific pricing, various forms of bundling, two-part tariffs, nonlinear pricing, and third-degree price discrimination, using survey-based data on nearly 500 students’ valuations of 50 popular songs in early January, 2008. We find that various alternatives – including simple schemes such as pure bundling and two-part tariffs – can raise both producer and consumer surplus. Revenue could be raised by nearly 10 percent relative to profit-maximizing uniform pricing and by over a fifth relative to current $0.99 uniform pricing. Moreover, revenue could be increased by a tenth while maintaining consumer surplus at the high level accompanying current $0.99 uniform song pricing. While person-specific uniform pricing can raise revenue by three quarters, none of the non-discriminatory schemes raise revenue’s share of surplus above 35 percent. Even with sophisticated pricing, much of the area under the demand curve for this product cannot be appropriated as revenue.
Experts Online: An Analysis of Trading Activity in a Public Internet Chat Room

Abstract We analyze the trading activity in an Internet chat room over a 4-year period. The data set contains nearly 9000 trades from 676 traders. We find these traders are more skilled than retail investors analyzed in other studies. 55 percent make profits after transaction costs, and they have statistically significant α s of 0.17 percent per day after controlling for the Fama–French factors and momentum. Traders hold their winners 25 percent longer than their losers. 42 percent trade both long and short, with equal success rates, and almost double the profit per trade when short. The estimates show a strong influence from other traders, with a buy (sell) order 40.7 percent more likely to be of the same sign if there has been a recent post. Traders improve their skill over time, earning an extra $189 per month for each year of trading experience. They also gain expertise in trading particular stocks. Traders who raise their Herfindahl index by 0.1 raise their profitability by $46 per trade.
The effect of wind on the microwave emission from the ocean's surface at 37 GHz

The microwave brightness temperature measurements from the Electrically Scanned Microwave Radiometer (frequency = 37 GHz) are compared with oceanic wind measurements from data buoys. It is shown that the brightness temperature can be manipulated to yield a measure of the surface roughening which can be very well accounted for by a simple geometric optics model. The data of 1.4, 8.36 and 19.34 GHz were similarly manipulated and shown to require a surface with less slope variance than predicted by optical measurements. It is also shown that the surface may be treated as isotropic to an accuracy equivalent to the roughening produced by a 2 m/s wind speed increment.
Bonferroni-Based Size-Correction for Nonstandard Testing Problems

We develop powerful new size-correction procedures for nonstandard hypothesis testing environments in which the asymptotic distribution of a test statistic is discontinuous in a parameter under the null hypothesis. Examples of this form of testing problem are pervasive in econometrics and complicate inference by making size dicult to control. This paper introduces two sets of new size-correction methods that correspond to two dierent general hypothesis testing frameworks. The new methods are designed to maximize the power of the underlying test while maintaining correct asymptotic size uniformly over the parameter space specied by the null hypothesis. They involve the construction of critical values that make use of reasoning derived from Bonferroni bounds. The rst set of new methods provides complementary alternatives to existing size-correction methods, entailing substantially higher power for many testing problems. The second set of new methods provides the rst available asymptotically size-correct tests for the general class of testing problems to which it applies. This class includes hypothesis tests on parameters after consistent model selection and tests on super-ecient/har d-thresholding estimators. We detail the construction and performance of the new tests in three specic examples: testing after conservative model selection, testing when a nuisance parameter may be on a boundary and testing after consistent model selection.
Scalable Distributed Consensus to Support MPI Fault Tolerance

As system sizes increase, the amount of time in which an application can run without experiencing a failure decreases. Exascale applications will need to address fault tolerance. In order to support algorithm-based fault tolerance, communication libraries will need to provide fault-tolerance features to the application. One important fault-tolerance operation is distributed consensus. This is used, for example, to collectively decide on a set of failed processes. This paper describes a scalable, distributed consensus algorithm that is used to support new MPI fault-tolerance features proposed by the MPI 3 Forum's fault-tolerance working group. The algorithm was implemented and evaluated on a 4,096-core Blue Gene/P. The implementation was able to perform a full-scale distributed consensus in 222 µs and scaled logarithmically.
Early Chronotropic Incompetence Predicts the Need for Atropine During Dobutamine Stress Echocardiography

Abstract Analysis of heart rate responses in 130 patients undergoing dobutamine stress echocardiography revealed that heart rate response at 20 μg/kg/min predicted the eventual need for atropine in chronotropically incompetent patients. Administering atropine at intermediate doses of dobutamine rather than at peak stress may reduce test duration and provide a more balanced chronotropic and inotropic stress.
Latent Classes of Adolescent Posttraumatic Stress Disorder Predict Functioning and Disorder After 1 Year

Objective To identify latent classes of posttraumatic stress disorder (PTSD) symptoms in a national sample of adolescents, and to test their associations with PTSD and functional impairment 1 year later. Method A total of 1,119 trauma-exposed youth aged 12 through 17 years (mean = 14.99 years, 51% female and 49% male) participating in the National Survey of Adolescents–Replication were included in this study. Telephone interviews were conducted to assess PTSD symptoms and functional impairment at Waves 1 and 2. Results Latent Class Analysis revealed three classes of adolescent PTSD at each time point: pervasive disturbance, intermediate disturbance, and no disturbance. Three numbing and two hyperarousal symptoms best distinguished the pervasive and intermediate disturbance classes at Wave 1. Three re-experiencing, one avoidance, and one hyperarousal symptom best distinguished these classes at Wave 2. The Wave 1 intermediate disturbance class was less likely to have a PTSD diagnosis, belong to the Wave 2 pervasive disturbance class, and report functional impairment 1 year later compared with the Wave 1 pervasive disturbance class. The Wave 1 no disturbance class was least likely to have PTSD, belong to the pervasive disturbance class, and report functional impairment at Wave 2. Conclusions This study suggests that PTSD severity–distinguishing symptoms change substantially in adolescence and are not characterized by the numbing cluster, contrary to studies in adult samples. These results may help to explain inconsistent factor analytic findings on the structure and diagnosis of PTSD, and emphasize that developmental context is critical to consider in both research and clinical work in PTSD assessment and diagnosis.
Cosmological Questions for the European Southern Observatory Very Large Telescope

The next decade promises an observational revolution which will change cosmology for ever. The precise measurement of the angular anisotropy of the cosmic microwave background should specify to a few percent all of the parameters of the cosmological model which effect astrophysics. The growth of structure will then be determined (but not yet observed) until gravitational collapse becomes highly nonlinear and stars, galaxies and active galactic nuclei (AGN) form. Not all of the gas enters these collapsed objects, in part because of feed back: stars eject gas, and both stars and AGN emit ionizing radiation which heats the gas. Instead, the universe enters a prolonged out-of-equilibrium state, which we are in today, when its appearance is determined by the balance between three things: the parameters of the cosmological model, the efficiency with which matter enters various collapsed objects, the matter and energy released by those objects. The competition between these collapse and feedback processes determines the appearance of the universe today, and their study will replace the specification of the model as the long term focus of research in cosmology.
Comparative performance of tabu search and simulated annealing heuristics for the quadratic assignment problem

For almost two decades the question of whether tabu search (TS) or simulated annealing (SA) performs better for the quadratic assignment problem has been unresolved. To answer this question satisfactorily, we compare performance at various values of targeted solution quality, running each heuristic at its optimal number of iterations for each target. We find that for a number of varied problem instances, SA performs better for higher quality targets while TS performs better for lower quality targets.
The Hegemon's Purse: No Economic Peace Between Democracies

Cox & Drury broaden the democratic peace literature from the domain of militarized conflict to economic sanctions. Their analysis of economic sanctions data from 1978 through 2000 finds that democracies are more likely to enact sanctions but are less likely to do so against other democracies. In this article, their analysis is extended in three different ways: first, their methodology and sample size are improved; second, interactions between variables are examined; and, third, additional hypotheses are tested. This article finds that the substantive effects of joint democracy on the likelihood of sanctions disappear after accounting for the disproportionate role of the United States (and correcting for method); the United States has a significantly different pattern of implementing sanctions than other states; and the trade dependence of a potential sender plays a significant role in determining the likelihood of sanctions.