cssi/SciSciGPT-SciSciNet huggingface dataset:
Multiobjective Optimization of Rocket Engine Pumps Using Evolutionary Algorithm

A design optimization method for turbopumps of cryogenic rocket engines has been developed. Multiobjective evolutionary algorithm is used for multiobjective pump design optimizations. Performances of design candidates areevaluated by using the meanline pump flow-modeling method based on the Euler turbine equation coupled with empirical correlations for rotor efficiency. To demonstrate feasibility of the present approach, single-stage centrifugal pump and multistage pump design optimizations are performed. The number of pump performance evaluations necessary to obtain a reasonable pareto-optimal set for the conceptual rocket engine pump design will be investigated using the single-stage centrifugal pump design optimization. In both design optimizations the present method obtains hundreds of reasonable and uniformly distributed pareto-optimal solutions that include some designs outperforming the original design in total head while reducing input power by 1%. Detailed observation of the design results also reveals some important design criteria for turbopumps in cryogenic rocket engines. These results demonstrate the feasibility of the evolutionary algorithm-based multiobjective design optimization method in this field.
Group representations and the Euler characteristic of elliptically fibered Calabi–Yau threefolds

To every elliptic Calabi-Yau threefold with a section X there can be associated a Lie group G and a representationof that group. The group is determined from the Weierstrass model, which has singularities that are generi- cally rational double points; these double points lead to local factors of G which are either the corresponding A-D-E groups or some associated non-simply laced groups. The representationis a sum of representations coming from the local factors of G, and of other representations which can be associated to the points at which the singularities are worse than generic. This construction first arose in physics, and the requirement of anomaly can- cellation in the associated physical theory makes some surprising predictions about the connection between X and �. In particular, an explicit formula (in terms of �) for the Euler characteristic of X is predicted. We give a purely math- ematical proof of that formula in this paper, introducing along the way a new invariant of elliptic Calabi-Yau threefolds. We also verify the other geometric predictions which are consequences of anomaly cancellation, under some (mild) hypotheses about the types of singularities which occur. As a byproduct we also discover a novel relation between the Coxeter number and the rank in the case of the simply laced groups in the "exceptional series" studied by Deligne.
The Projective Geometry of the Gale Transform

Abstract The Gale transform, an involution on sets of points in projective space, appears in a multitude of guises and in subjects as diverse as optimization, coding theory, theta functions, and recently in our proof that certain general sets of points fail to satisfy the minimal free resolution conjecture (see Eisenbud and Popescu, 1999, Invent. Math. 136 , 419–449). In this paper we reexamine the Gale transform in the light of modern algebraic geometry. We give a more general definition in the context of finite (locally) Gorenstein subschemes. We put in modern form a number of the more remarkable examples discovered in the past, and we add new constructions and connections to other areas of algebraic geometry. We generalize Goppa's theorem in coding theory and we give new applications to Castelnuovo theory. We also give references to classical and modern sources.
Biomimetic synthesis via polyepoxide cyclizations

The biomimetic synthesis of trans,syn,trans-fused polycyclic ether natural products involving a cascade of stereospecific and regioselective oxacyclizations of polyepoxide sub- strates is described as applied to the synthesis of polyoxepane and polypyran structures. In addition, an extension of biomimetic polyene cyclizations to terpenoid natural products is outlined.
Bush v. Gore and the Effect of New Source Review on Power Plant Emissions

New Source Review (NSR) is a Clean Air Act regulation that requires electric utilities to meet emission standards when making modifications to existing power plants. The regulation increases the cost of replacing worn out parts, and limits the firm’s scope of potential capital investments. Such restrictions may lead to greater retirements and lower utilization, adversely affecting profits. Prior to the 2000 presidential election, investors expected Bush to have a narrower interpretation of NSR than Gore. Therefore, we use changes in stock prices to estimate the effect on profits of differences in NSR policy. Our results indicate that investors expected the average boiler to be $38 million more valuable under the Bush administration. Over the boilers’ lifetimes, the additional utilization will have increased emissions by 19 million tons of sulfur dioxide, 5.9 million tons of nitrogen oxides and 980 million tons of carbon dioxide, relative to natural gas generation.
Flush-Mounted Steady-Periodic Heated Film With Application to Shear-Stress Measurement

Surface-mounted heated films have been used for fluid-flow measurement for many years. Recently unsteady heating of such surface films has been explored experimentally. In this paper steady-periodic heating of a surface-mounted film is studied analytically. Wall effects and axial heat conduction in the fluid are included. The temperature is found as an exact integral expression constructed from separate Green’s function formulations in the fluid flow and in the solid wall that are matched at the fluid-solid interface. Results for temperature, obtained by quadrature, are reported for several flow speeds and several steady-periodic frequencies. The results show that steady-periodic heating has potential for shear-stress measurement because the heating frequency may be tuned to maximize the temperature response at the shear stress of interest. Thermal calibration of these sensors is discussed, and simulated calibration curves are given.
Effect of Confounding in the Association Between Circumcision Status and Urinary Tract Infection

Summary Objectives To estimate the impact of confounding in the association between circumcision status and urinary tract infection from epidemiological factors, sample collection, and health-seeking behaviors in the first year of life. Methods Beginning with the assumption that true urinary tract infection occurred equally regardless of circumcision status, a Markov model incorporating the differences in the rates of prematurity, of urine collection, of false positive urine specimens, and of health-seeking behaviors in infant boys based on circumcision status was developed. Using this model, the rates of false-positive urine cultures, asymptomatic bacteriuria, and true urinary tract infection detected in the first year of life were estimated and contrasted. Error of the model was estimated using Monte Carlo simulations. Results Keeping the incidence of true urinary tract infection constant between groups, the factors included in the model could account for urinary tract infection being diagnosed 4.27 times more frequently in non-circumcised males under a year of age. Conclusions Previously reported differences in the rate of urinary tract infection by circumcision status could be entirely due to sampling and selection bias. Until clinical studies adequately control for sources of bias, circumcision should not be recommended as a preventive for urinary tract infection.
Specimen Size Effect of the Thermal Diffusivity/Conductivity of Aluminum Nitride

It has been generally found that the thermal diffusivity/conductivity of AIN measured by the laser-flash technique decreases with decreasing specimen size. The results of this study indicate that much of this effect can be attributed to the relatively large temperature rises for thin specimens, especially for high-energy laser pulses, and results from the combination of the noninearity of the commonly used type of IR detector and the strongly negative temperature dependence of the thermal diffusivity of AIN. The experimental results indicate that for reliable data, the specimen temperature rise at thermal equilirium should be kept to less than 1°C by using specimens with a thickness near 3 mm in combination with keeping the pulse energy to a reasonable minimum by attenuation of the laser beam by passing it through an aqueous solution of CuSO4.
Electrode Polarization of Glasses

The low-frequency dielectric characteristics of soda-lime and sodium-silicate glasses were determined as a function of temperature, electrode materials, surface condition, and specimen thickness. The resulting large dielectric constant (often called electrode polarization) was dependent on surface condition of the glass specimen when evaporated metal electrodes were used and insensitive to surface condition when paste electrodes were used. The space charge mechanism was suggested as an explanation for these phenomena. The dependence of the dielectric constant on frequency and specimen thickness agrees with predictions of theory
Capacity Regions and Bounds for a Class of Z-Interference Channels

We define a class of Z-interference channels for which we obtain a new upper bound on the capacity region. The bound exploits a technique first introduced by Korner and Marton. A channel in this class has the property that, for the transmitter-receiver pair that suffers from interference, the conditional output entropy at the receiver is invariant with respect to the transmitted codewords. We compare the new capacity region upper bound with the Han/Kobayashi achievable rate region for interference channels. This comparison shows that our bound is tight in some cases, thereby yielding specific points on the capacity region as well as sum capacity for certain Z-interference channels. In particular, this result can be used as an alternate method to obtain sum capacity of Gaussian Z-interference channels. We then apply an additional restriction on our channel class: the transmitter-receiver pair that suffers from interference achieves its maximum output entropy with a single input distribution irrespective of the interference distribution. For these channels, we show that our new capacity region upper bound coincides with the Han/Kobayashi achievable rate region, which is therefore capacity-achieving. In particular, for these channels superposition encoding with partial decoding is shown to be optimal and a single-letter characterization for the capacity region is obtained.
Unbiased estimates of galaxy scaling relations from photometric redshift surveys

Many physical properties of galaxies correlate with one another, and these correlations are often used to constrain galaxy formation models. Such correlations include the colour-magnitude relation, the luminosity-size relation, the fundamental plane, etc. However, the transformation from observable (e.g. angular size, apparent brightness) to physical quantity (physical size, luminosity) is often distance dependent. Noise in the distance estimate will lead to biased estimates of these correlations, thus compromising the ability of photometric redshift surveys to constrain galaxy formation models. We describe two methods which can remove this bias. One is a generalization of the V max method, and the other is a maximum-likelihood approach. We illustrate their effectiveness by studying the size-luminosity relation in a mock catalogue, although both methods can be applied to other scaling relations as well. We show that if one simply uses photometric redshifts one obtains a biased relation; our methods correct for this bias and recover the true relation.
Fast stochastic global optimization

A new stochastic optimization strategy is introduced which cascades many Metropolis-like procedures to sample a Boltzmann distribution at fixed temperatures. Global optimization of an objective f(x) in a certain class is shown to require O((/spl Delta//T/sub low/)/sup 2/) computational effort where /spl Delta/=max/sub x,x'/(f(x)-f(x')) and T/sub low/ is a low enough temperature that the Boltzmann function of f at T/sub low/ acceptably small except for optimal x. This theoretical advantage is confirmed by experimental results which are presented for a problem in vector quantization and for seven standard test problems in nonlinear optimization. >
Aspects of dialectics and non-linear dynamics

Three principles of dialectical analysis are examined in terms of non-linear dynamics models. The three principles are the transformation of quantity into quality, the interpenetration of opposites, and the negation of the negation. The first two of these especially are interpreted within the frameworks of catastrophe, chaos and emergent dynamics complexity theoretic models, with the concept of bifurcation playing a central role. Problems with this viewpoint are also discussed. Copyright 2000 by Oxford University Press.
Asymptotic stability of congestion control systems with multiple sources

Congestion in computer networks is the main reason for reduced performance and poor quality of service; therefore, a good congestion control system is essential. The basic property of any control system is stability. We consider the problem of stability in computer network congestion control systems with multiple sources, which is the most common case in general purpose computer networks. The main result of the note is the proof that for congestion control systems with linear controllers (e.g., ATM-ABR), the stability of the congestion control system with a single source is equivalent to the stability of the one with multiple sources. In other words, for the considered congestion control systems, if the system is stable for a single source it will be stable for an arbitrary large number of sources. The proof is based on a well-known necessary and sufficient stability test.
Designing New Business Startups: Entrepreneurial, Organizational, and Ecological Considerations

The startups of 14 educational-software companies are investigated from three different perspectives: entrepreneurial, organizational, and ecological. The performance and stages of development of the new firms are viewed from each perspective. The entrepreneurial perspective concentrates on the characteristics and background of the founding individual. The organizational perspective looks at the planning and initial development processes of the firms. The ecological perspective uses the population of firms as a level of analysis and is concerned with the success of the industry as a whole. These three perspectives each contribute significantly to the designing of startups of new organizations.
An object-oriented approach to nested data parallelism

This paper describes an implementation technique for integrating nested data parallelism into an object-oriented language. Data-parallel programming employs data aggregates called "collections" and expresses parallelism as operations performed over the elements of a collection. When the elements of a collection are also collections, then there is the possibility for "nested data parallelism." Few current programming languages support nested data parallelism however. In an object-oriented framework, a collection is a single object. Its type defines the parallel operations that may be applied to it. Our goal is to design and build an object-oriented data-parallel programming environment supporting nested data parallelism. Our initial approach is built upon three fundamental additions to C++. We add new parallel base types by implementing them as classes, and add a new parallel collection type called a "vector" that is implemented as a template. Only one new language feature is introduced: the foreach construct, which is the basis for exploiting elementwise parallelism over collections. The strength of the method lies in the compilation strategy, which translates nested data-parallel C++ into ordinary C++. Extracting the potential parallelism in nested foreach constructs is called "flattening" nested parallelism. We show how to flatten foreach constructs using a simple program transformation. Our prototype system produces vector code which has been successfully run on workstations, a CM-2 and a CM-5. >
Relativistic plasma klystron amplifier in connection with application to high gradient accelerators

A novel plasma klystron amplifier is presented in which current modulation of a relativistic electron beam is achieved by the unstable two-stream interaction between the electron beam and a plasma column. A model to describe current modulation is developed. Due to a relatively large growth rate of the instability, required interaction length of the beam and plasma column is short for most applications. A full current modulation can be achieved in the plasma klystron amplifiers. >
On the power of neural networks for solving hard problems

Abstract This paper deals with a neural network model in which each neuron performs a threshold logic function. An important property of the model is that it always converges to a stable state when operating in a serial mode. This property is the basis of the potential applications of the model such as associative memory devices and combinatorial optimization. One of the motivations for use of the model for solving hard combinatorial problems is the fact that it can be implemented by optical devices and thus operate at a higher speed than conventional electronics. The main theme in this work is to investigate the power of the model for solving NP-hard problems and to understand the relation between speed of operation and the size of a neural network. In particular, it will be shown that for any NP-hard problem the existence of a polynomial size network that solves it implies that NP = co-NP. Also, for the Traveling Salesman Problem (TSP), even a polynomial size network that gets an e-approximate solution does not exist unless P = NP. The above results are of great practical interest, because right now it is possible to build neural networks which will operate fast but are limited in the number of neurons they contain.
Synthesis of novel chiral binaphthyl phosphorus ligands and their applications in Rh-catalyzed asymmetric hydrogenation

Abstract A series of new chiral mono- or bidentate phosphorus ligands were efficiently prepared through a key intermediate ( S )-4-chloro-4,5-dihydro-3 H -4-phosphacyclohepta[2,1- a ;3,4- a ′]binaphthalene and its derivatives. These ligands were applied in the Rh-catalyzed asymmetric hydrogenation of α-dehydro amino acids, enol acetates, itaconates, and enamides. Good to excellent enantioselectivities were obtained (up to 99.5% ee).
Catalytic Enantioselective Nazarov Cyclization: Construction of Vicinal All‐Carbon‐Atom Quaternary Stereocenters

The diastereoselective asymmetric synthesis of vicinal all-carbon-atom quaternary stereocenters is a challenging problem in organic synthesis for which only few solutions have been described. A catalytic asymmetric Nazarov cyclization of fully substituted dienones that provides cyclopentenone derivatives with vicinal quaternary stereocenters in high optical purity and as single diastereoisomers is now reported.
Fifteen years of dancing with vanadium

The advances in vanadium chemistry over the past 15 years are discussed in the areas of solution chemistry, coordination chemistry, and bioinorganic chemistry and will be presented using the perspectives of "What exists in solution?", "What is its structure?", "How does it react?", and "What are its biological effects?". Current and future challenges will be described briefly.
High-speed path length scanning using a Herriott cell delay line

Summary form only given. Optical coherence tomography (OCT) has been extensively investigated as a diagnostic tool in a variety of medical fields, demonstrating its feasibility as a high speed, non-invasive, high resolution in vivo and in situ imaging modality. Typical OCT systems require a mechanically translating reference arm mirror to achieve axial scanning. Scan velocities for galvonometer based scanning systems are limited by mechanical inertia to approximately 3 cm/s with repetition rates of /spl sim/100 Hz. In order to remove motion artifact for imaging in vivo, image acquisition rates of several frames per second are necessary. We demonstrate a simple, low cost, alternative scanning delay line capable of scanning over several millimeters at 2 kHz repetition frequency. The system uses a multi-pass mirror geometry based on a Herriott type cell, which accumulates differential delays in each pass.
Determination of the Interior Structure of Transiting Planets in Multiple-Planet Systems

Tidal dissipation within a short-period transiting extrasolar planet perturbed by a companion object can drive orbital evolution of the system to a so-called tidal fixed point, in which the apses of the transiting planet and its perturber are aligned, and variations in orbital eccentricities vanish. Significant contribution to the apsidal precession rate is made by gravitational quadrupole fields, created by the transiting planets tidal and rotational distortions. The fixed-point orbital eccentricity of the inner planet is therefore a strong function of its interior structure. We illustrate these ideas in the specific context of the recently discovered HAT-P-13 exoplanetary system, and show that one can already glean important insights into the physical properties of the inner transiting planet. We present structural models of the planet, which indicate that its observed radius can be maintained for a one-parameter sequence of models that properly vary core mass and tidal energy dissipation in the interior. We use an octupole-order secular theory of the orbital dynamics to derive the dependence of the inner planet's eccentricity, e_b, on its tidal Love number, k_(2b). We find that the currently measured eccentricity, e_b = 0.021 ± 0.009, implies 0.116 < k_(2b) < 0.425, 0 M_⊕ < M_(core) < 120 M_⊕, and 10,000 < Q_b < 300,000. Improved measurement of the eccentricity will soon allow for far tighter limits to be placed on all of these quantities, and will provide an unprecedented probe into the interior structure of an extrasolar planet.
Time-lapse image registration using the local similarity attribute

We present a method to register time-lapse seismic images based on the local-similarity attribute. We define registration as an automatic point-by-point alignment of time-lapse images. Stretching and squeezing a monitor image and computing its local similarity to the base image allows us to detect an optimal registration even in the presence of significant velocity changes in the overburden. A by-product of this process is an estimate of the ratio of the interval seismic velocities in the reservoir interval. We illustrate the proposed method and demonstrate its effectiveness using both synthetic experiments and real data from a time-lapse experiment in the Duri field, Indonesia.
Signaling in Venture Capitalist—New Venture Team Funding Decisions: Does It Indicate Long-Term Venture Outcomes?

According to signaling theory, new venture teams (NVTs) can communicate to venture capitalists and other potential investors both a “value” signal and a “commitment” signal, based on the level of personal investment in a venture. Venture capitalists (VCs) typically want to know if a NVT is really committed to a venture and if its members truly believe that a venture has wealth creating potential. Team members can convey signals via their investment behavior. We test our hypotheses based on a sample of 183 VC-backed ventures that we tracked over a ten-year time period. These data indicate that the signals sent to VCs in the early stages of the funding process do not appear to have any significant relationship with long-term venture outcomes. We explore possible explanations for these findings, as well as their implications for signaling theory and future research.
Electrolyte Additive Chemistry and Feature Size-Dependent Impurity Incorporation for Cu Interconnects

Impurity levels in plated Cu have been much studied, in particular their role in the room temperature recrystallization (or “self-annealing”) of plated Cu films. 3 The recrystallization of electroplated Cu is important since large-grained metal (having a “bamboo” structure) is desirable for good interconnect electromigration performance. Past impurity studies have often involved blanket Cu films; ones where plated Cu damascene features are studied are fewer in number. Zhang et.al. found higher Cl signals using TOF-SIMS for 90nm wide Cu interconnect lines as compared to wide square pads (600nm on a side), suggesting more impurities are incorporated into the narrow patterned lines than in wide structures (and also that impurity studies on blanket films may have limited applicability to damascene structures). In this study, we characterize the impurity levels of Cu plated into 40nm CD structures for two types of Cu plating chemistries. One chemistry yields relatively pure Cu (“pure” Cu), while another gives a higher level of incorporated impurities (“doped” Cu), both as observed for blanket films. The impurity levels for each type are shown in Table 1. Room temperature recrystallization behavior is shown in Figure 1 by relative changes in deposited film sheet resistance (Rs). The Rs values changes more slowly for the “doped” Cu film. The behavior of the narrow 40nm CD lines is contrasted with that of larger CD structures. The impact of this featuresize dependent impurity incorporation on interconnect reliability will also be discussed.
Fast matrix multiplication is stable

We perform forward error analysis for a large class of recursive matrix multiplication algorithms in the spirit of Bini and Lotti [Numer. Math. 36:63–72, 1980]. As a consequence of our analysis, we show that the exponent of matrix multiplication (the optimal running time) can be achieved by numerically stable algorithms. We also show that new group-theoretic algorithms proposed in Cohn and Umans [Foundations of Computer Science, 44th Annual IEEE Symposium, pp. 438–449, 2003] and Cohn et al. [Foundations of Computer Science, 46th Annual IEEE Symposium, pp. 379–388, 2005] are all included in the class of algorithms to which our analysis applies, and are therefore numerically stable. We perform detailed error analysis for three specific fast group-theoretic algorithms.
Minimum Energy Trap States of Dual-Spin Spacecraft

The general solution to the bearing axis motor torque required to escape a minimum energy trap state is presented for oblate dual-spin spacecraft. A simplified, reduced order analysis of the bearing torque is then obtained for the case of small static imbalances, dynamic imbalances, and asymmetries on the rotor and the stator. This analysis is extended to include large asymmetry on one of the bodies. The results are applied to the design of the Galileo spacecraft.
High Fidelity Modeling of Thermal Relaxation and Dissociation of Oxygen

A master equation study of vibrational relaxation and dissociation of oxygen is conducted using state-specific O2–O transition rates, generated by extensive trajectory simulations. Both O2–O and O2–O2 collisions are concurrently simulated in the evolving nonequilibrium gas system under constant heat bath conditions. The forced harmonic oscillator model is incorporated to simulate the state-to-state relaxation of oxygen in O2–O2 collisions. The system of master equations is solved to simulate heating and cooling flows. The present study demonstrates the importance of atom-diatom collisions due to the extremely efficient energy randomization in the intermediate O3 complex. It is shown that the presence of atomic oxygen has a significant impact on vibrational relaxation time at temperatures observed in hypersonic flow. The population of highly-excited O2 vibrational states is affected by the amount of atomic oxygen when modeling the relaxation under constant heat bath conditions. A model of coupled state-to-...
The direct fluorination of acetone

Abstract A synthesis for hexafluoroacetone using elemental fluorine is reported. Previously hexafluoroacetone and other ketones have been difficult to prepare using fluorination based syntheses.
Scattering and propagation impacts on shipboard radar systems

The tropospheric electromagnetic parabolic equation routine (TEMPER) has been used extensively in conjunction with system simulations in support of operational US Navy exercises and in various ship's system design tradeoff studies. The theory, features, and performance of TEMPER are described briefly, followed by a discussion of atmospheric measurement and resolution issues. Two high-resolution measurement systems are reviewed. Radar system simulation using environmental information is discussed, and several performance predictions in postulated propagation conditions are presented. Finally, a prototype environmental assessment system designed for use on board AEGIS ships is briefly described. >
An algorithm for simulation of electrochemical systems with surface-bulk coupling strategies

In Buoni and Petzold (2007) [13] we described a new algorithm for simulation of electrochemical systems on two-dimensional irregular, time-dependent domains. Here we show how to extend the algorithm to three dimensions. We demonstrate our three-dimensional algorithm by simulating copper electrodeposition into a via structure. This problem poses challenges for the coupling of the dilute electrolyte (bulk) model to the surface dynamics model, which involves a complex network of reactions. To handle this coupling, we introduce a new and highly effective semi-implicit method.
The unified logging infrastructure for data analytics at Twitter

In recent years, there has been a substantial amount of work on large-scale data analytics using Hadoop-based platforms running on large clusters of commodity machines. A less-explored topic is how those data, dominated by application logs, are collected and structured to begin with. In this paper, we present Twitter's production logging infrastructure and its evolution from application-specific logging to a unified "client events" log format, where messages are captured in common, well-formatted, flexible Thrift messages. Since most analytics tasks consider the user session as the basic unit of analysis, we pre-materialize "session sequences", which are compact summaries that can answer a large class of common queries quickly. The development of this infrastructure has streamlined log collection and data analysis, thereby improving our ability to rapidly experiment and iterate on various aspects of the service.
Economic Theory and the Spatial Mismatch Hypothesis

The spatial mismatch hypothesis is that "Serious limitations on black residential choice, combined with the steady dispersal of jobs from central cities, are responsible for the low rates of employment and low earnings of Afro-American workers" (Kain, 1994, p. 371). Despite a wealth of related empirical studies, there has been little work formalising the hypothesis. This paper presents a trade-theoretic model, with three regions (downtown, suburbia and the rest of the world), four goods (a tradable home good, untraded services, a tradable foreign good and land), and two factors (skilled and unskilled workers). Blacks are constrained to live downtown but by incurring commuting costs can work in suburbia. Several exogenous changes are considered (for example a fall in transport costs between suburbia and the rest of the world) which may lead simultaneously to a fall in the downtown unskilled wage and to job suburbanisation, and which therefore provide a theoretical basis for the hypothesis.
Numerical indications of a q-generalised central limit theorem

We provide numerical indications of the q-generalised central limit theorem that has been conjectured ( TSALLIS C., Milan J. Math., 73 (2005) 145) in nonextensive statistical mechanics. We focus on N binary random variables correlated in a scale-invariant way. The correlations are introduced by imposing the Leibnitz rule on a probability set based on the so-called q-product with q ≤ 1. We show that, in the large-N limit (and after appropriate centering, rescaling, and symmetrisation), the emerging distributions are qe-Gaussians, i.e., p(x) ∝ [1-(1-q_e), β(N)x^2]^{1/(1-q_e)}, with q_e=2-(1/q), and with coefficients β(N) approaching finite values β(∞). The particular case q=q_e=1 recovers the celebrated de Moivre-Laplace theorem.
SEU/SRAM as a process monitor

The SEU/SRAM is a 4-kbit static random access memory (SRAM) designed to detect single-event upsets (SEU's) produced by high-energy particles, either in space or on the ground. This device was used to determine the distribution of the memory cell spontaneous flip potential. The variance in this potential was determined to be due to the variation in the threshold voltage of one of the n-FET's found in the memory cell. For a 1.2-/spl mu/m CMOS process, the standard deviation of the n-FET VT was found to be 8 mV. This structure provides substantial statistical data; 4096 data points are measured. Using cumulative distribution and residual plots, outlier cells, such as stuck cells and nonnormally distributed cells, are easily identified. >
Age at Marriage and Marital Instability: Revisiting the Becker-Landes-Michael Hypothesis *

An early age at first marriage is known to be associated with a high risk of divorce. Yet it has been suggested that beyond a certain point, the relationship between age at marriage and marital instability may become positive, because as unmarried women begin to hear their biological clock tick, they may settle for matches far from the optimal. Analyses based on cycles 5 and 6 of the National Surveys of Family Growth show that the relationship between age at marriage and marital instability is strongly negative up to the late twenties, with a flattening of the curve thereafter.
Trade liberalization and income distribution

Empirical work relating trade liberalization and income distributed has iden- tified an important anomaly. The Stolper-Samuelson theorem predict trade liberalization will shift income toward a country's abundant factor. For developing countries, this suggests liberalization will principally benefit the abundant unskilled labor. Yet extensive empirical studies have identified many cases with a contrary result. This paper develops a simple theoretical explanation for this anomaly. It shows that countries which are labor abundant in a global sense may see wages decline with liberalization if they are capital abundant in a local sense. The current absence of empirical work that would allow us to identify the relevant local abundance implies that virtually all assertions regarding anticipated distributional consequences of trade liberalization are without foundation. There may likewise be important implications for industrialized countries that border developing countries undertaking trade liberalization, particularly in regard to the incentives for migration.
Antitrust Immunity and International Airline Alliances

Most of the major carriers worldwide have joined one of three international airline alliances. The U.S. Department of Transportation has granted immunity from the U.S. antitrust laws to many carriers within these alliances. This article assesses the competitive effects and efficiencies associated with such grants. A grant of antitrust immunity to carriers in an alliance reduces competition in routes where these carriers offer competing flights, and the data show that fares paid by passengers for travel in non-stop trans-Atlantic flights are higher in routes with fewer independent competitors. The data also show that the alliances can produce pricing efficiencies for trans-Atlantic passengers who travel with connecting itineraries, but antitrust immunity within an alliance is not necessary to achieve such efficiencies.
Three-dimensional time-marching aeroelastic analyses using an unstructured-grid Euler method

Modifications to a three-dimensional, implicit, upwind, unstructured-grid Euler code for aeroelastic analysis of complete aircraft configurations are described. The modifications involve the addition of the structural equations of motion for their simultaneous time integration with the governing flow equations. The paper presents a detailed description of the time-marching aeroelastic procedures and presents comparisons with experimental data to provide an assessment of the capability. Flutter results are shown for an isolated 45-deg swept-back wing and a supersonic transport configuration with a fuselage, clipped delta wing, and two identical rearward-mounted engine nacelles. Comparisons are made between computed and experimental flutter characteristics to assess the accuracy of the aeroelastic results.
Metal–metal multiple bonding in C3-symmetric bimetallic complexes of the first row transition metals

Metal–metal multiple bonds have been an intense area of focus in inorganic chemistry for many decades as a result of their fundamentally interesting bonding properties, as well as their potential applications in multielectron transfer and small molecule activation processes. Much of what is known in this field revolves around 2nd and 3rd row transition metals, with fundamental knowledge lacking in the area of bonds between elements of the first transition series. The smaller size and tendency of first row ions to adopt high-spin electron configurations weaken metal–metal interactions and serve to complicate the interpretation of the electronic structure and bonding in bimetallic species containing first row transition metals. Furthermore, traditional tetragonal “paddlewheel” complexes dominate the metal–metal multiple bond literature, and only recently have researchers begun to take advantage of the weaker ligand field in three-fold symmetric bimetallic complexes to encourage more favourable metal–metal bonding interactions. In the past 5 years, several research groups have exploited three-fold symmetric frameworks to investigate new trends in metal–metal bonding involving the first row transition metals. This feature article serves to highlight recent achievements in this area and to use C3-symmetric systems as a model to better understand the fundamental aspects of multiple bonds featuring first row transition metals.
Assessing the Impact of ABFT and Checkpoint Composite Strategies

Algorithm Based Fault Tolerant (ABFT) approaches promise unparalleled scalability and performance in failure-prone environments. With the advances in the theoretical and practical understanding of algorithmic traits enabling such approaches, a growing number of frequently used algorithms (including all widely used factorization) have been proven ABFT-capable. In the context of larger applications, these algorithms provide a temporal section of the execution when the data is protected by it's own intrinsic properties, and can be algorithmically recomputed without the need of checkpoints. However, while typical scientific applications spend a significant fraction of their execution time in library calls that can be ABFT-protected, they interleave sections that are difficult or even impossible to protect with ABFT. As a consequence, the only fault-tolerance approach that is currently used for these applications is checkpoint/restart. In this paper we propose a model to investigate the efficiency of a composite protocol, that alternates between ABFT and checkpoint/restart for effective protection of an iterative application composed of ABFT-aware and ABFT-unaware sections. We validate this model using a simulator. The model and simulator show that this composite approach drastically increases the performance delivered by an execution platform, especially at scale, by providing means to rarefy the checkpoints while simultaneously decreasing the volume of data needed to be check pointed.
Aromatics from pyrones: para-substituted alkyl benzoates from alkenes, coumalic acid and methyl coumalate

The Diels–Alder reaction of coumalic acid and methyl coumalate with unactivated alkenes provides only para-substituted adducts in good yield.
Displacement sensor based on pyroelectric thick films and contactless light-spot cursor

A sensor is presented to measure translational displacement exploiting the position-dependent signals generated by pyroelectric films when excited by a movable light-emitting diode that works as a contactless light-spot cursor. The pyroelectric films are made of lead zirconate titanate (PZT) screen-printed on alumina substrate by the thick-film technology. The sensor employs a differential configuration which minimizes the sensitivity toward mechanical vibrations and microphonics caused by the piezoelectric response of PZT. An electronic circuit based on excitation modulation and synchronous rectification rejects the interference from thermal and light background. The sensor principle, design, and manufacturing are described, and experimental results from the device characterization are reported.
PONIARD: A Programmable Optical Networking Infrastructure for Advanced Research and Development of Future Internet

Motivated by the design goals of Global Environment for Network Innovation (GENI), we consider how to support the slicing of link bandwidth resources as well as the virtualization of optical access networks and optical backbone mesh networks. Specifically, in this paper, we study a novel programmable mechanism called optical orthogonal frequency division multiplexing (OFDM)/orthogonal frequency division multiple access (OFDMA) for link virtualization. Unlike conventional time division multiplexing (TDM)/time division multiple access (TDMA) and wavelength division multiplexing (WDM)/wavelength division multiple access (WDMA) methods, optical OFDM/OFDMA utilizes advanced digital signal processing (DSP), parallel signal detection (PSD), and flexible resource management schemes for subwavelength level multiplexing and grooming. Simulations as well as experiments are conducted to demonstrate performance improvements and system benefits including cost-reduction and service transparency.
The Political Context of Sentencing: An Analysis of Community and Individual Determinants

Most studies of jail or prison sentence length focus on whether offender characteristics produce sentencing differentials after legal effects have been controlled, but the findings in the literature have not been consistent, probably because most studies have been based on a few jurisdictions. To see if political effects explain these discrepancies, this study of 337 jurisdictions in seven states analyzes interaction effects between external political influences and offender attributes after holding constant multiple individual and environmental factors. To adjust for censoring, Tobit is used to analyze the length of sentences, while state differences are held constant with state-specific dummy variables. When interaction terms are not included, the results are consistent with prior research. But the inclusion of political interactions produces findings suggesting that African Americans and males receive longer sentences when local courts are embedded in conservative political environments where a law-and-order presidential candidate received more votes. These results support theoretical claims that punishment is an intensely political process.
Synthesis of [3.3.0] bicyclic isoxazolidinyl nucleosides

The isoxazolidine derivative 6, prepared from an intermolecular 1,3-dipolar cycloaddition of the (5S)-unsaturated lactone 5 and N-methylnitrone, was effectively used for the synthesis of [3.3.0] bicyclic isoxazolidinyl cytidine 4a and thymidine 4b.
Electrolyte-based on-demand and disposable microbattery

A micromachined battery based on liquid electrolyte and metal electrodes for on-demand and disposable usages has been successfully demonstrated. The microbattery uses gold as the positive electrode and zinc as the negative electrode and is fabricated by using the standard surface micromachining technology. Two kinds of electrolytes have been tested, including the combination of sulfuric acid/hydrogen peroxide and potassium hydroxide. The operation of the battery can be on-demand by putting a droplet of electrolyte to activate the operation. Theoretical voltage and capacity of the microbattery are formulated and compared with experimental results. The experimental study shows that a maximum voltage of 1.5 V and maximum capacity of 122.2 /spl mu/W-min have been achieved by using a single droplet of about 0.5 /spl mu/l of sulfuric acid/hydrogen peroxide.
Input-output stability of sampled-data linear time-varying systems

In this paper we consider the input-output stability of feedback systems consisting of a continuous-time, linear, time-varying plant with a discrete time, linear time-varying controller. These results generalize some of the results of Chen and Francis (1991, 1995) where the plant is restricted to be time-invariant. >
Iron isotopes in the Amazon River system: Weathering and transport signatures

Abstract Trace metal clean plankton tows, river samples, aerosol leachates, and porewater samples from the Amazon River system were measured for their iron isotopic composition. The overall isotopic range observed was 1.5‰ with Fe isotopic variability observed between different types of tributaries. Dissolved Fe and suspended load Fe from two main channel sites were isotopically similar (≈ − 0.1 to − 0.3‰). In contrast, the dissolved Fe and suspended load Fe from an organic rich tributary, the Negro River, were isotopically distinct with the dissolved slightly isotopically heavy (+ 0.3‰) and the suspended load isotopically light (− 0.9‰). The isotopically lightest sample from the Amazon region was shelf porewater (− 1.3‰). In river water–seawater mixing experiments, the Fe isotopic signal of dissolved Fe of river water was modified by flocculation of isotopically heavy Fe. The variability of the Fe isotopic composition of natural samples including biological and aqueous samples demonstrates that significant fractionation is associated with Fe biogeochemistry in the environment.
A Model for Bomblet Ejection from Missiles

Abstract : Ejection of bomblets from a missile which does not have an active ejector mechanism is studied. A model is developed for this process which yields a measure of ejection time, bomblet position at early times and trajectories. The model involves centrifugal (roll rate effect) and aerodynamic forces. A gross knowledge of the flow field is necessary and an estimate for forces on a bomblet while it is penetrating a shear layer is crucial. It is shown that a bomblet may be trapped in a separated flow pocket. Results from the model are consistent with some observations and have been useful in design and performance studies. (Author)
Rounding corners of polygons and the embedded contact homology of T 3

The embedded contact homology (ECH) of a 3‐manifold with a contact form is a variant of Eliashberg‐Givental‐Hofer’s symplectic field theory, which counts certain embedded J ‐holomorphic curves in the symplectization. We show that the ECH of T 3 is computed by a combinatorial chain complex which is generated by labeled convex polygons in the plane with vertices at lattice points, and whose differential involves “rounding corners”. We compute the homology of this combinatorial chain complex. The answer agrees with the Ozsvath‐Szabo Floer homology HF C .T 3 /.