cssi/SciSciGPT-SciSciNet huggingface dataset:
Dark Energy Search with Supernovae

Abstract To determine the nature of dark energy from observational data, it is important that we use model-independent and optimal methods. We should probe dark energy using its density (allowed to be a free function of cosmic time) instead of its equation of state. We should minimize gravitational lensing effect on supernovae by flux-averaging. We need to include complementary data (for example, from the cosmic microwave background (CMB) and large scale structure (LSS)) in a consistent manner to help break the degeneracy between the dark energy density and the matter density fraction. We should push for ambitious future supernova surveys that can observe a large number of supernovae at the highest possible redshifts. I discuss these and other issues that will be important in our quest to unravel the mystery of the nature of dark energy. Current supernova, CMB, and LSS data already rule out dark energy models with dark energy densities that vary greatly with time; with the cosmological constant model providing an excellent fit to the data. A precise measurement of dark energy density as a free function of cosmic time will have a fundamental impact on particle physics and cosmology.
Ion separation using a Y-junction carbon nanotube

Using molecular dynamics simulations, we show that a Y-junction carbon nanotube can be used to separate K+ and Cl− ions from a KCl solution. The Y-junction nanotube is formed by connecting two smaller carbon nanotube branches of sizes (5, 5) and (6, 6) to a larger (8, 8) carbon nanotube. While uncharged (5, 5) and (6, 6) carbon nanotubes show close to zero occupancy of K+ and Cl− ions, we show that a negatively charged (5, 5) carbon nanotube and a positively charged (6, 6) carbon nanotube can be selective to K+ and Cl− ions, respectively. By performing molecular dynamics simulations on the entire system comprising the Y-junction carbon nanotube, the KCl solution chamber, the push plate and the receiving chamber, we show that as the electrolyte moves through the (8, 8) carbon nanotube the K+ and the Cl− ions can be selectively transported through the (5, 5) and the (6, 6) carbon nanotube, respectively. The formation of ion pairs can affect the separation efficiency and we discuss the conditions under which perfect separation can be obtained.
Detection of mutual inconsistency in distributed databases

Abstract A Distributed Database Management System should guarantee the consistency of databases at all sites in the system. In particular when the databases are replicated, mutual consistency among all copies of an item should be maintained. Network partitioning is a difficult kind of failure to deal with. A strategy known as the optimistic approach allows transactions to be run independently in different parts of the distributed system formed due to a partition. The mutual consistency among the copies of an item cannot be taken for granted in this scenario. Thus a natural requirement of the system then is that it determines whether or not the database is consistent and tries to resolve any inconsistencies. A simple scheme is presented in this paper to detect mutual inconsistency when partitioned databases merge. This scheme is similar to that of D. S. Parker et al . [ IEEE Trans. Software Eng. (May 1983)] in spirit although it is more general. In contrast to that of S. Davidson [ ACM Trans. Database Systems (Sept. 1984), 456–482] where a certain amount of information is maintained about each transaction run after the partition, our scheme maintains certain information with each data item accessed after the partition.
Intrinsic construction of invariant functions on simple Lie algebras

Abstract An algorithm for constructing primitive adjoint-invariant functions on a complex simple Lie algebra is presented. The construction is intrinsic in the sense that it does not resort to any representation. A primitive invariant function on the whole Lie algebra is obtained by lifting a coordinate function on a Kostant slice of the Lie algebra. Such an intrinsic construction of invariant functions is most useful for the bigger exceptional Lie algebras such as the Eʼs. The Maple implementation of this algorithm is outlined at the end and will be applied to these exceptional Lie algebras in a future work.
The Dirichlet and Neumann and Dirichlet-to-Neumann problems in quadrature, double quadrature, and non-quadrature domains

We demonstrate that solving the classical problems mentioned in the title on quadrature domains when the given boundary data is rational is as simple as the method of partial fractions. A by-product of our considerations will be a simple proof that the Dirichlet-to-Neumann map on a double quadrature domain sends rational functions on the boundary to rational functions on the boundary. The results extend to more general domains if rational functions are replaced by the class of functions on the boundary that extend meromorphically to the double.
Synthesis of Substituted Quinolines by the Electrophilic Cyclization of N-(2-Alkynyl)anilines

Quinolines substituted in the 3-position by an iodo or phenylseleno group are readily prepared in good to excellent yields by the reaction of propargylic anilines with appropriate electrophiles under mild reaction conditions.
Density of states in chromium alloys

Both the spin- and charge-density waves of Cr alloys have significant effects on the joint density-of-states {rho}({omega}) of the nested electron and hole Fermi surfaces below the N{acute e}el temperature T{sub N}. The random-phase approximation is used to evaluate {rho}({omega}) within a three-band model of Cr alloys. In the commensurate phase of the spin-density wave, {rho}({omega}) contains a single energy gap 2{Delta}. At zero temperature, 2{Delta} reaches a maximum value of about 370 meV and spans the Fermi energy, which is shifted upwards by the presence of a charge-density wave (CDW). In the incommensurate phase, {rho}({omega}) contains two energy gaps {Delta}{sub 1}{sup {prime}} and {Delta}{sub 1} above and below midgap states. If the CDW order parameter {delta} vanishes, then {Delta}{sub 1}{sup {prime}}={Delta}{sub 1} and both reach a maximum of about 130 meV at T=0; if {delta} is nonzero, then {Delta}{sub 1}{sup {prime}}{lt}{Delta}{sub 1}. A third energy gap {Delta}{sub 2} includes both the midgap states as well as the smaller gaps {Delta}{sub 1} and {Delta}{sub 1}{sup {prime}}. For pure Cr, {Delta}{sub 2} reaches a maximum value of about 450 meV at T=0. Unlike {Delta}{sub 1} and {Delta}{sub 1}{sup {prime}}, {Delta}{sub 2} does not vanish at T{sub N} but decreases to aboutmore » 370 meV. Our results are compared with those obtained earlier from a two-band model in the absence of the CDW. This paper also clarifies the assumptions made by the three-band model and the role of the unpaired holes which reside on the larger of the two nested Fermi surfaces. {copyright} {ital 1997} {ital The American Physical Society}« less
Long-Range Dependence in U.S. Home Price Volatility

The existence of GARCH effects in a financial price series means that the probability of large losses is much higher than standard mean-variance analysis suggests. Accordingly, several recent papers have investigated whether GARCH effects exist in the U.S. housing market, as changes in house prices can have far-ranging impacts on defaults, foreclosures, tax revenues and the values of mortgage-backed securities. Some research in finance indicates that the conditional variance of some assets exhibits far greater persistence, or even “long memory”, than is accounted for in standard GARCH models. If house prices do indeed have this very persistent volatility, properly estimating the conditional variance to allow for such persistence is crucial for optimal portfolio management. We examine a number of U.S. metropolitan areas, and find that, for those with significant GARCH effects, more than half indeed exhibit the very high persistence found in other assets such as equities. We also find that, for those markets exhibiting such persistent volatility, C-GARCH models typically do a better job in forecasting than standard GARCH models. Moreover, there is some tentative evidence that metro areas with the fastest appreciation may be most likely to have such long memory conditional variance. These findings should help in improving risk management, through, for instance the construction of better-specified value-at-risk models.
A Re-examination of the Fragility of Evidence from Cointegration- Based Tests of Foreign Exchange Market Efficiency

We re-examine Sephton and Larsen's (1991) conclusion that cointegration-based tests for market efficiency suffer from temporal instability. We improve upon their research by i) including a drift term in the vector error correction model (VECM) in the Johansen procedure, ii) correcting the likelihood ratio test statistic for finite-sample bias, and iii) fitting the model over longer data sets. We show that instability of the Johansen cointegration tests mostly disappears after accounting for these two factors. The evidence is even more stable in favour of no cointegration when we apply our analysis to longer data sets
The argonne fragment mass analyzer

The Fragment Mass Analyzer is being constructed for use in heavy-ion experiments with the ATLAS superconducting linear accelerator system at Argonne National Laboratory. It is a triple-focussing recoil mass spectrometer, designed to separate nuclear reaction recoils from the primary heavy-ion beam and disperse them in M/Q (mass/unit charge) at the focal plane. The main ion-optical elements are two electric dipoles and a magnetic dipole, with the electric dipoles (E) symmetrically placed before and after the magnet (M). The elements are spaced such that the position energy dispersion (x/delta/sub E/) and the angle energy dispersion (theta/delta/sub E/) of the system both vanish (energy focus). Here delta/sub E/ stands for ..delta..E/E, the fractional energy deviation from the central energy. The energy-dispersionless EME configuration was first used by Cormier and Stwertka for the Recoil Mass Spectrometers at Rochester, and was also chosen by Spolaore et al. for the Recoil Mass Spectrometer at the Laboratori Nazionali di Legnaro in Padua. Although the energy dispersion is canceled, the M/Q dispersion is not, and the device performs as a mass spectrometer. When used in the energy-dispersionless mode, the EME combination of elements offers some distinct advantages over designs containing Wien filters or a single electrostatic element.more » These advantages include wider M/Q and energy acceptances and superior rejection of the primary beam (/approximately/10/sup /minus/12/). The energy focus condition implies isochronous orbits for particles having the same M/Q and energy but with differing emission angles at the target, an important feature when used with pulsed beam accelerators like ATLAS. 8 refs., 4 figs., 1 tab.« less
Estimating Economies of Scope Using Profit Function: A Dual Approach of the Normalized Quadratic Profit Function

Abstract Theoretical relationships between parameters of the normalized quadratic profit and cost functions are derived allowing for economies of scope to be calculated using profit function estimates. An empirical example confirms that the cost function is recovered using the estimated profit function.
Nonlinear inferential control for process applications

Abstract The increasing performance demands on controlled chemical operations, coupled with the lack of appropriate measurement technology, motivates the need for nonlinear inferential control approaches. In this article, an overview of nonlinear inferential control approaches is presented, with an emphasis on the estimation component of the algorithm and logical extensions of the linear theory. Applications of the algorithms to process applications are reviewed, and new theoretical and application results are presented.
Maximum cross‐entropy generalized series reconstruction

This article addresses the classical image reconstruction problem from limited Fourier data. In particular, we deal with the issue of how to incorporate constraints provided in the form of a high-resolution reference image which approximates the desired image. A new algorithm is described which represents the desired image using a family of basis functions derived from translated and rotated versions of the reference image. The selection of the most efficient basis function set from this family is guided by the principle of maximum cross-entropy. Simulation and experimental results have shown that the algorithm can achieve high resolution with a small number of data points while accounting for relative misregistration between the reference and measured data. The technique proves to be useful for a number of time-sequential magnetic resonance imaging applications, for which significant improvement in temporal resolution can be obtained, even as the object undergoes bulk motion during the acquisition. © 1999 John Wiley & Sons, Inc. Int J Imaging Syst Technol 10, 258–265, 1999
Typed common intermediate format

Application languages are very e ective in solving speci c software problems. Unfortunately, they pose great challenges to reliable and e cient implementations. In fact, most existing application languages are slow, interpreted, and have poor interoperability with general-purpose languages. This paper presents a framework on building highquality systems environment for multiple advanced languages. Our key innovation is the use of a common typed intermediate language, named FLINT, to model the semantics and interactions of various language-speci c features. FLINT is based on a predicative variant of the Girard-Reynolds polymorphic calculus F!, extended with a very rich set of primitive types and functions. FLINT provides a common compiler infrastructure that can be quickly adapted to generate compilers for new general-purpose and domain-speci c languages. With its single uni ed type system, FLINT serves as a great platform for reasoning about crosslanguage interoperations. FLINT types act as a glue to connect language features that complicate interoperability, such as mixed data representations, multiple function calling conventions, and di erent memory management protocols. In addition, because all runtime representations are determined by FLINT types, languages compiled under FLINT can share the same system-wide garbage collector and foreign function call interface.
Au(I)-catalyzed annulation of enantioenriched allenes in the enantioselective total synthesis of (-)-rhazinilam.

Highly stereoselective Au(I)-catalyzed pyrrole additions to enantioenriched allenes afford a unique entry to optically active heterocycles. Asymmetric quaternary carbons can be installed with concurrent heterocycle annulation utilizing this methodology. The enantioenriched allenes are conveniently obtained by catalytic asymmetric acyl halide−aldehyde cyclocondensations and SN2‘ ring opening of the resulting enantioenriched β-lactones. An enantioselective total synthesis of (−)-rhazinilam highlights the potential utility of this reaction technology in target-oriented synthesis.
Quantifying lunar soil composition with partial least squares modeling of reflectance

Abstract Retrieval of lunar soil composition is commonly achieved through optical remote sensing in which spectral characteristics of returned lunar samples are related to their constituents. Partial least squares (PLS) and principal component regression (PCR) were applied to the dataset characterized by the Lunar Soil Characterization Consortium (LSCC) to estimate the content of FeO, Al 2 O 3 and TiO 2 in the soils. The goal of this study was to test whether the conversion of reflectance to single scattering albedo (SSA) via Hapke’s radiative transfer model is able to improve the performance of PLS and PCR. Results from PLS and PCR modeling of SSA spectra indicate that the conversion does not necessarily improve the performance of PLS and PCR, and this depends on the chemical considered, the way to select the number of optimal factors, and how the data were pretreated. The conversion failed to accommodate the large deviation of highland samples with low FeO, TiO 2 and high Al 2 O 3 .
CEO turnover and the reduction of price sensitivity

Abstract We examine managerial compensation and wealth sensitivities around CEO changes. The average new CEO is incentivized to increase the risk of the firm primarily because he holds significantly less stock than his predecessor, and in fact riskier policy choices are subsequently implemented. Similar results are obtained in a subsample of CEO changes that are due to retirements and deaths, which alleviates concerns about endogeneity. Our findings indicate that firms seem to be limited in their ability to mitigate the risk-averse behavior caused by large CEO shareholdings.
Preparation of Acrylophenones and 2-Alkyl Indanones Utilizing Hexamethylenetetramine as an Inexpensive Mannich Reagent.

Abstract Hexamethylenetetramine/acetic anhydride-promoted α-methylenation of aryl alkyl ketones followed by acid-catalyzed cyclization of the resulting acrylophenones produce 2-alkyl indanones in excellent yields.
Synthesis and anti-norovirus activity of pyranobenzopyrone compounds.

Abstract During the last decade, noroviruses have gained media attention as the cause of large scale outbreaks of gastroenteritis on cruise ships, dormitories, nursing homes, etc. Although noroviruses do not multiply in food or water, they can cause large outbreaks because approximately 10–100 virions are sufficient to cause illness in a healthy adult. Recently, it was shown that the activity of acyl-coenzyme A:cholesterol acyltransferase-1 (ACAT1) enzyme may be important in norovirus infection. In search of anti-noroviral agents based on the inhibition of ACAT1, we synthesized and evaluated the inhibitory activities of a class of pyranobenzopyrone molecules containing amino, pyridine, substituted quinolines, or 7,8-benzoquinoline nucleus. Three of the sixteen evaluated compounds possess ED 50 values in the low micrometer range. 2-Quinolylmethyl derivative 3A and 4-quinolylmethyl derivative 4A showed ED 50 values of 3.4 and 2.4 μM and TD 50 values of >200 and 96.4 μM, respectively. The identified active compounds are suitable for further modification for the development of anti-norovirus agents.
DEFORMED HARISH-CHANDRA HOMOMORPHISM FOR THE CYCLIC QUIVER

In the case of cyclic quiver we prove that the deformed Harish-Chandra map whose existence was conjectured by Etingof and Ginzburg is well defined. As an application we prove a Kirillov-type formula for the cyclotomic Bessel function.
Experimental paradigms for the hypnotic investigation of dream symbolism.

(1961). Experimental Paradigms for the Hypnotic Investigation of Dream Symbolism. International Journal of Clinical and Experimental Hypnosis: Vol. 9, No. 3, pp. 105-117.
Rossby Wave Instability of Keplerian Accretion Disks

We find a linear instability of nonaxisymmetric Rossby waves in a thin nonmagnetized Keplerian disk when there is a local maximum in the radial profile of a key function (r)≡(r)S2/Γ(r), where −1=(∇×v)/Σ is the potential vorticity, S=P/ΣΓ is the entropy, Σ is the surface mass density, P is the vertically integrated pressure, and Γ is the adiabatic index. We consider in detail the special case where there is a local maximum in the disk entropy profile S(r). This maximum acts to trap the waves in its vicinity if its height-to-width ratio max(S)/Δr is larger than a threshold value. The pressure gradient derived from this entropy variation provides the restoring force for the wave growth. We show that the trapped waves act to transport angular momentum outward. A plausible way to produce an entropy variation is when an accretion disk is starting from negligible mass and temperature, therefore, negligible entropy. As mass accumulates by either tidal torquing, magnetic torquing, or Roche-lobe overflow, confinement of heat will lead to an entropy maximum at the outer boundary of the disk. Possible nonlinear developments from this instability include the formation of Rossby vortices and the formation of spiral shocks. What remains to be determined from hydrodynamic simulations is whether or not Rossby wave packets (or vortices) "hold together" as they propagate radially inward.
The hyperspherical four-fermion problem

The problem of a few interacting fermions in quantum physics has sparked intense interest, particularly in recent years owing to connections with the behaviour of superconductors, fermionic superfluids and finite nuclei. This review addresses recent developments in the theoretical description of four fermions having finite-range interactions, stressing insights that have emerged from a hyperspherical coordinate perspective. The subject is complicated, so we have included many detailed formulae that will hopefully make these methods accessible to others interested in using them. The universality regime, where the dominant length scale in the problem is the two-body scattering length, is particularly stressed, including its implications for the famous BCS–BEC crossover problem. Derivations and relevant formulae are also included for the calculation of challenging few-body processes such as recombination.
Production of Fluorine by the Electrolysis of Calcium Fluoride‐Containing Tetrafluoroborate Melts

Tetrafluoroborate melts have been shown to be viable electrolytes for the electrochemical production of fluorine from dissolved . The anode reaction at pyrolytic graphite electrodes apparently involves the oxidation of and/or F− to yield and . may be used to trap ; the resulting may be reused in the bath. Observed anode current efficiencies are generally on the order of 50–60% at an optimum anode current density of 40 mA/cm2. The cathode reaction at tin and/or zinc cathodes involves the reduction of Ca2+ to the metal along with the reduction of alkali metal ions to the respective metals. The presence of zinc in the cathode pool appears to favor the deposition of calcium over that of alkali metals.
Electron-inertia effects on magnetic field reconnection driven by perturbations on boundaries

In this Letter, we consider electron-inertia effects on the magnetic field reconnection induced by perturbing the boundaries of a slab of plasma with a magnetic neutral surface inside. The subsequent evolution of the current sheet formed at the magnetic neutral surface via ideal MHD development is found to be divided into two distinct stages: (1) the electron-inertia stage for small times (when the current sheet is very narrow); (2) the resistive-diffusion stage for large times. The current sheet mainly undergoes exponential damping in the electron-inertia regime while the bulk of the diffusion occurs in the resistivity regime.
Kinematics and control of multifingered hands with rolling contact

The kinematics of rolling contact are derived for two surfaces of arbitrary shape rolling on each other. The kinematic equations are applied to a multifingered hand manipulating some object of arbitrary shape in three dimensions, and a scheme is presented for the control of such a hand which is a generalization of the computed torque method of control of robot manipulators. In implementing the control, it is required that all applied forces lie within the friction cone of the object so that sliding does not occur. The theory has been validated by dynamic graphical simulations of the resulting closed-loop system for several examples. >
Quantum associative memory

Abstract This paper combines quantum computation with classical neural network theory to produce a quantum computational learning algorithm. Quantum computation (QC) uses microscopic quantum level effects to perform computational tasks and has produced results that in some cases are exponentially faster than their classical counterparts. The unique characteristics of quantum theory may also be used to create a quantum associative memory (QuAM) with a capacity exponential in the number of neurons. This paper combines two quantum computational algorithms to produce such a quantum associative memory. The result is an exponential increase in the capacity of the memory when compared to traditional associative memories such as the Hopfield network. The paper covers necessary high-level quantum mechanical and quantum computational ideas and introduces a QuAM. Theoretical analysis proves the utility of the memory, and it is noted that a small version should be physically realizable in the near future.
Methods for Handling Drilled Gas in Oil-Based Drilling Fluids

This paper presents calculation methods for predicting the behavior of drilled-gas contamination of oil-based drilling fluids. The methods are verified by experiments conducted in a 6,000-ft (1828.8 m) test well. This paper also presents field-handling procedures developed with the calculation methods.
Treatment of incompatible initial and boundary data for parabolic equations in higher dimension

A new method is proposed to improve the numeri- cal simulation of time dependent problems when the initial and boundary data are not compatible. Unlike earlier methods limited to space dimension one, this method can be used for any space dimension. When both methods are applicable (in space dimen- sion one), the improvements in precision are comparable, but the method proposed here is not restricted by dimension.
A general rationale for a governmental role in the relief of large risks

The government often provides relief against large risks, such as disasters. A simple, general rationale for this role of government is considered here that applies even when private contracting to share risks is not subject to market imperfections. Specifically, the optimal private sharing of large risks will not result in complete coverage against them. Hence, when such risks eventuate, the marginal utility to individuals of government relief may exceed the marginal value of public goods. Consequently, social welfare may be raised if the government reduces public goods expenditures and directs these freed resources toward individuals who have suffered losses.
The Casimir effect for fermions in one dimension

Abstract We study the Casimir problem for a fermion coupled to a static background field in one space dimension. We examine the relationship between interactions and boundary conditions for the Dirac field. In the limit that the background becomes concentrated at a point (a “Dirac spike”) and couples strongly, it implements a confining boundary condition. We compute the Casimir energy for a masslike background and show that it is finite for a stepwise continuous background field. However the total Casimir energy diverges for the Dirac spike. The divergence cannot be removed by standard renormalization methods. We compute the Casimir energy density of configurations where the background field consists of one or two sharp spikes and show that the energy density is finite except at the spikes. Finally we define and compute an interaction energy density and the force between two Dirac spikes as a function of the strength and separation of the spikes.
Liberal Values in International Criminal Law A Critique of Erdemović

Using the Erdemovic decision as its starting point, the article examines the philosophical foundations of international criminal law. It asserts that international criminal law, properly understood, represents a liberal legal system, emphasizing the rights of the accused over the interests of the prosecution or the goals of international peace and security. Using the work of Ronald Dworkin, it argues that international jurists should apply principles that invoke a respect for human rights and individual autonomy over ‘policy’. Thus, it argues that the reasoning of the Appeals Chamber of the International Criminal Tribunal for the former Yugoslavia was flawed when it determined that duress did not constitute a complete defence in Erdemovic.
School Tracking and Access to Higher Education Among Disadvantaged Groups

Abstract When students are tracked into vocational and academic secondary schools, access to higher education is usually restricted to those who complete an academic track. Postponing such tracking may increase university attendance among disadvantaged students if additional time in school enables them to catch up with their more privileged counterparts. However, if ability and expectations are fairly well set by an early age, postponing tracking during adolescence may not have much effect. This paper exploits an educational reform in Romania to examine the impact of postponing tracking on the proportion of disadvantaged students graduating from university using a regression discontinuity (RD) design. We show that, although students from poor, rural areas and with less educated parents were significantly more likely to finish an academic track and become eligible to apply for university after the reform, this did not translate into an increase in university completion. Our findings indicate that simply postponing tracking, without increasing the slots available in university, is not sufficient to improve access to higher education for disadvantaged groups.
Implications of Modularity on Product Design for the Life Cycle

Growing concern for the environment has spurred interest in environmentally conscious design and manufacturing. The concept of Design for the Life Cycle encompasses all aspects of a product’s life cycle from initial conceptual design, through normal product use, to the eventual disposal of the product. A product’s architecture, determined during the configuration design stage, plays a large role in determining the product’s life cycle characteristics. In this paper, modularity of product architectures with respect to life cycle concerns, not just product functionality and structure, is defined and applied in the analysis of architecture characteristics. A principal hypothesis underlying this work is that high degree of life cycle modularity can be beneficial across all viewpoints of interest because all interested people will view the product similarly and consistently. An architecture decomposition algorithm from the literature is adopted for partitioning architectures into modules from each life cycle viewpoint. Two measures of modularity are proposed: one that measures module correspondence between several viewpoints, and another that measures coupling between modules. The algorithm and measures are applied to the analysis and redesign of an automotive center console. Results of applying the algorithm and measures accurately reflected our intuitive understanding of the original center console design and predicted the results of our redesign. Furthermore, these measures incorporate only configuration information of the product; hence, can be used before detailed design stages.
Wavelength assignment to minimize requirement on tunable range of optical transceivers in WDM networks

In this paper we consider WDM networks with a tunable transmitter and a fixed-wavelength receiver at each station (similar results hold when the transmitter is fixed and the receiver is tunable). Traditionally, each station is required to be able to access all wavelength channels used in the network. Such requirement limits the number of wavelengths that can be exploited in a WDM network up to the size of the resolvable wavelength set of optical transceivers, which is very limited with current technology. In this paper we observe that this requirement is actually an overkill. To realize a communication topology, physical or logical, it is sufficient that the tunable range of the transmitter at each station covers all the wavelengths of the receivers at its neighboring stations. This observation leads to the study of optimal wavelength assignment to minimize the tunability requirement while still guaranteeing that each receiver has a unique wavelength channel. This optimization problem is shown to NP-complete in general and approximation algorithms with provable performance guarantees are presented. When the communication topologies are complete graphs, de Bruijin digraphs, Kautz digraphs, shuffle or rings, the optimal solutions are provided. Finally, we present tight lower bounds when the communication topology is a hypercube.
Uniform approximations for the M/G/1 queue with subexponential processing times

This paper studies the asymptotic behavior of the steady-state waiting time, W ?, of the M/G/1 queue with Subexponential processing times for different combinations of traffic intensities and overflow levels. In particular, we provide insights into the regions of large deviations where the so-called heavy-traffic approximation and heavy-tail asymptotic hold. For queues whose service time distribution decays slower than $e^{-\sqrt{t}}$ we identify a third region of asymptotics where neither the heavy-traffic nor the heavy-tail approximations are valid. These results are obtained by deriving approximations for P(W ?>x) that are either uniform in the traffic intensity as the tail value goes to infinity or uniform on the positive axis as the traffic intensity converges to one. Our approach makes clear the connection between the asymptotic behavior of the steady-state waiting time distribution and that of an associated random walk.
The Fermionic contribution to the spectrum of the area operator in nonperturbative quantum gravity

The role of fermionic matter in the spectrum of the area operator is analysed using the Baez - Krasnov framework for quantum fermions and gravity. The result is that the fermionic contribution to the area of a surface S is equivalent to the contribution of purely gravitational spin network's edges tangent to S. Therefore, the spectrum of the area operator is the same as in the pure gravity case.
The Expected Advantage of Asynchrony

This paper studies the implicit costs of synchronization and the possible gains arising from avoiding synchronization in asynchronous environments. An asynchronous generalization of the PRAM model called the APRAM model is used and appropriate complexity measures are defined. The advantage that asynchrony provides is illustrated by analyzing two algorithms: a parallel summation algorithm which proceeds along an implicit complete binary tree and a recursive doubling algorithm which proceeds along a linked list.
Modeling the conditional mean and variance of the short rate using diffusion, GARCH, and moving average models

This article introduces a two‐factor‐discrete‐time‐stochastic‐volatility model that allows for departures from linearity in the conditional mean and incorporates serially correlated unexpected news, asymmetry, and level effects into the definition of conditional volatility of the short rate. The new class of econometric specifications nests many popular existing symmetric and asymmetric GARCH as well as diffusion models of the short‐term interest rate. This study attempts to determine the correct specification of conditional mean and variance of the short rate by developing a more general econometric framework that allows for nonlinear effects in the drift of the short rate, and that defines the conditional volatility as a nonlinear function of unexpected information shocks and interest rate levels. The existing and alternative models are compared in terms of their ability to capture the stochastic behavior of the short‐term riskless rate. The empirical results indicate that the relative performance of the two‐factor models in predicting the future level and variance of interest‐rate changes is superior to the nested models. © 2000 John Wiley & Sons, Inc. Jrl Fut Mark 20:717–751, 2000
Compatibility of DAMA/LIBRA dark matter detection with other searches in light of new Galactic rotation velocity measurements

The DAMA/NaI and DAMA/LIBRA annual modulation data, which may be interpreted as a signal for the existence of weakly interacting dark matter (WIMPs) in our galactic halo, are re-examined in light of new measurements of the local velocity relative to the galactic halo. In the vicinity of the Sun, the velocity of the Galactic disk has been estimated to be 250 km/s rather than 220 km/s [1]. Our analysis is performed both with and without the channeling effect included. The best fit regions to the DAMA data are shown to move to slightly lower WIMP masses. Compatibility of DAMA data with null results from other experiments (CDMS, XENON10, and CRESST I) is investigated given these new velocities. A small region of spin-independent (elastic) scattering for 7–8 GeV WIMP masses remains at 3σ. Spin-dependent scattering off of protons is viable for 5–15 GeV WIMP masses for direct detection experiments (but has been argued by others to be further constrained by Super-Kamiokande due to annihilation in the Sun).
Absorption of scalars by extended objects

We derive the low energy absorption cross section of minimal scalars for a very generic class of geometries, that includes, among others, black holes, strings, p-branes, as well as intersecting brane configurations. The scalar field can be absorbed across a regular surface (a horizon) of finite area, or across a zero area throat, which may be singular or regular. Then we focus on some particular cases and compare with the results obtained using microscopic models at weak coupling. Exact agreement is found for the absorption by the non-degenerate ground state of effective strings. For geometries where the throat is singular, we show that absorption through the stretched horizon yields correct results for degenerate states. For non-degenerate (ground) states we introduce a stretched throat, and show that it accounts for the correct dependence on frequency, charges, and moduli for the absorption by ground states of BPS fundamental strings. It is also shown to lead to the correct dependence on frequency for extremal D-branes.
Effectiveness of gentamicin for gonorrhoea treatment: systematic review and meta-analysis.

Objectives The development of resistance to multiple antimicrobial agents has limited treatment options for gonorrhoea. The potential emergence of cephalosporin resistance in Neisseria gonorrhoeae and cephalosporin allergy in some patients make it necessary to evaluate the effectiveness of other available antimicrobial agents. Gentamicin is widely available in the USA and is used for gonorrhoea treatment in several countries. We conducted a systematic review of the medical literature to assess the effectiveness of gentamicin for treatment of uncomplicated urogenital gonococcal infections. Methods Two reviewers assessed relevant articles and independently selected studies that met prespecified selection criteria (including systematic enrolment and assignment to treatment and culture-confirmed diagnosis and outcome). Summary measures for selected studies were pooled using inverse variance-weighted averages with fixed effects. Heterogeneity was assessed using I 2 , which estimates proportion (0–100%) of variability attributable to heterogeneity between studies. Pooled percentage with negative follow-up culture was compared with Centers for Disease Control and Prevention (CDC) criteria for selection of recommended therapy (lower 95% CI of efficacy ≥95%). Results Twenty-nine potentially relevant studies were identified; three met inclusion criteria. Two studies used 240 mg intramuscular gentamicin and one used 280 mg. Percentages with negative culture after single-dose treatment were 90.7% (n=86), 91.4% (n=220) and 95.0% (n=40). Pooled percentage with negative culture after single-dose treatment was 91.5% (95% CI 88.1% to 94.0%, I 2 =0%). Conclusions Gentamicin does not meet current CDC criteria for recommended treatment of gonorrhoea. However, if cephalosporin resistance emerges, gentamicin may be a useful alternative agent. Evaluation of additional regimens, including combination therapy, is warranted.
Irradiation as a tool for studying solid-state amorphization phenomena

An overview of selected experimental results on amorphization induced by irradiation and by ion implantation is first presented. This overview and other general observations on the microstructural evolution that precedes the transition to the amorphous state of irradiated crystalline materials expose some of the important data that must be accounted for by theory. A perspective of our present understanding of irradiation-induced amorphization is then presented. As described in previous work, the theory assumes a localized buildup of complexes (coupled interstitial/ vacancy pairs) to a critical value as the mechanism of amorphization. The theory of complex formation implies that the production of a defective state characterized by localized anisotropic distortions of the crystalline lattice leads to amorphization. It is proposed that this concept can be generalized to encompass solid-state amorphization transitions other than those induced by irradiation. Examples available in the literature to support this idea are presented. It is therefore suggested that irradiation can be used as a valuable tool to study other solid-state amorphization transitions.
A critical assessment of satellite drag and atmospheric density modeling

Abstract This paper examines atmospheric drag models and data usage involved with propagating near-Earth satellites. Many studies, and even some International standards try to promote one model over another, rather than identifying the behavior of the numerous parameters necessary to select the best model for a particular mission and application. We briefly summarize existing information, and quantify sources of uncertainty in satellite propagation resulting from several atmospheric models, or from the treatment of input data indices. The goal is for researchers to understand the relative impact of using different models and data indices so they can properly assess which model and data input to use.
XML access control using static analysis

Access control policies for XML typically use regular path expressions such as XPath for specifying the objects for access-control policies. However such access-control policies are burdens to the query engines for XML documents. To relieve this burden, we introduce static analysis for XML access-control. Given an access-control policy, query expression, and an optional schema, static analysis determines if this query expression is guaranteed not to access elements or attributes that are hidden by the access-control policy but permitted by the schema. Static analysis can be performed without evaluating any query expression against actual XML documents. Run-time checking is required only when static analysis is unable to determine whether to grant or deny access requests. A side effect of static analysis is query optimization: access-denied expressions in queries can be evaluated to empty lists at compile time. We further extend static analysis for handling value-based access-control policies and introduce view schemas.
Stock-based pay in new economy firms

Abstract Ittner, Lambert, and Larcker (J. Accounting Economics (2003) this issue) present compelling evidence that new economy firms rely more on stock-based compensation than do old economy firms, based on 1998 and 1999 data from a proprietary sample of companies. I complement the ILL results by analyzing data over a longer time period (1992–2001) and, more importantly, document the effect of the 2000 market crash on stock-based pay in new economy firms. Finally, I offer evidence supporting the conjecture that differences in pay practices between new and old economy firms reflect accounting considerations, perceived costs, and competitive inertia.
Approximating a MIMO, 1D Diffusion System to a Low Order, State-Space Form in Order to Facilitate Controller Design

Chemical distribution is an important factor in many biological systems, driving the phenomenon known as chemotaxis. In order to properly study the effects of various chemical inputs to an in vitro biological assay, it is necessary to have strict control over the spatial distribution of these chemicals. This distribution is typically governed by diffusion, which by nature is a distributed parameter system (DPS), dependent on both space and time. Much study and literature within the controls community has been devoted to DPS, whose dynamics are marked by partial differential equations or delays. They span an infinite-dimensional state-space, and the mathematical complexity associated with this leads to the development of controllers that are often highly abstract in nature. In this paper, we present a method of approximating these systems and expressing them in a manner that makes a DPS amenable to control using a very low order model. In particular, we express the PDE for one-dimensional chemical diffusion as a two-input, two-output state-space system and show that standard controllers can manipulate the outputs of interest, using pole placement and integral control via an augmented state model.Copyright © 2010 by ASME
Limits on the power of concurrent-write parallel machines

Abstract The computation of specific functions using the most general form of concurrent-read-concurrent-write parallel RAM is considered. It is shown that such a machine can compute any function of Boolean inputs in time log n − log log n + O(1) given a polynomial number of processors and memory cells and that this bound is tight for integer addition. Despite this evidence of the power of the model we show that a very simple function, namely parity, requires time Ω ( log n ) to compute given a polynomial bound on the number of processors, independent of the number of memory cells.
Parameterized Tractability of Edge-Disjoint Paths on Directed Acyclic Graphs

Given a graph and terminal pairs $(s_i,t_i)$, $i\in[k]$, the edge-disjoint paths problem is to determine whether there exist $s_{i}t_{i}$ paths, $i\in[k]$, that do not share any edges. We consider this problem on acyclic digraphs. It is known to be NP-complete and solvable in time $n^{O(k)}$ where $n$ is the number of nodes. It has been a long-standing open question whether it is fixed-parameter tractable in $k$, i.e., whether it admits an algorithm with running time of the form $f(k)\,n^{O(1)}$. We resolve this question in the negative: we show that the problem is $W[1]$-hard, hence unlikely to be fixed-parameter tractable. In fact it remains $W[1]$-hard even if the demand graph consists of two sets of parallel edges. On a positive side, we give an $O(m+k^{O(1)}\,k!\,n)$ algorithm for the special case when $G$ is acyclic and $G+H$ is Eulerian, where $H$ is the demand graph. We generalize this result (1) to the case when $G+H$ is “nearly” Eulerian, and (2) to an analogous special case of the unsplittable flow problem, a generalized version of disjoint paths that has capacities and demands.
Statistical Structures Underlying Quantum Mechanics and Social Science

Common observations of the unpredictability of human behavior and the influence of one question on the answer to another suggest social science experiments are probabilistic and may be mutually incompatible with one another, characteristics attributed to quantum mechanics (as distinguished from classical mechanics). This paper examines this superficial similarity in depth using the Foulis-Randall Operational Statistics language. In contradistinction to physics, social science deals with complex, open systems for which the set of possible experiments is unknowable and outcome interference is a graded phenomenon resulting from the ways the human brain processes information. It is concluded that social science is, in some ways, “less classical” than quantum mechanics, but that generalized “quantum” structures may provide appropriate descriptions of social science experiments. Specific challenges to extending “quantum” structures to social science are identified.
Composition operators within singly generated composition C*-algebras

Let ϕ be a linear-fractional self-map of the open unit disk D, not an automorphism, such that ϕ(ζ) = η for two distinct points ζ,η in the unit circle ∂D. We consider the problem of determining which composition operators, acting on the Hardy space H 2, lie in C*(C ϕ ,K), the unital C*-algebra generated by the composition operator C ϕ and the ideal K of compact operators. This necessitates a companion study of the unital C*-algebra generated by the composition operators induced by all parabolic non-automorphisms with common fixed point on the unit circle.