cssi/SciSciGPT-SciSciNet huggingface dataset:
SAR-ECCM using phase-perturbed LFM chirp signals and DRFM repeat jammer penalization

This work is concerned with developing radar signaling strategies and algorithms that enhance the ability of a synthetic aperture radar (SAR) to image targets in the presence of digital radio frequency memory (DRFM) repeat jammers. The approach is based on a manipulation/alteration of the transmitted signal and/or its parameters in the fast-time domain at every position of the synthetic aperture (pulse repetition interval (PRI)); this scheme is known as pulse diversity. In particular, we utilize a modulated form of the transmitted chirp signal and/or vary the rate of the chirp at each PRI; the modulation and/or the rate is varied from one PRI to another, and these variations are only known to the user. The merits of these pulse diversity methods are studied using the autocorrelation and cross-correlation of these signals. We also present a signal processing method for penalizing a DRFM jammer that tries to repeat the radar signal.
UNDERSTANDING EXCHANGE RATE VOLATILITY WITHOUT THE CONTRIVANCE OF MACROECONOMICS

Exchange rate regimes differ primarily by the activity of the exchange rate, not observable macroeconomic ‘fundamentals’. Fixed exchange rates are typically stable and floating exchange rates are volatile, but macro phenomena are regime-independent. Fundamentals only seem to be relevant for exchange rates at low frequencies or when inflation is high. A basic task of international finance is explaining these cross-regime differences in exchange rate volatility. The evidence suggests that a switch in exchange rate policy is accompanied by a change in market structure; macroeconomic considerations are superfluous. We formalize this observation in a non-linear model with multiple equilibria. (This abstract was borrowed from another version of this item.)
High-throughput biological cell classification featuring real-time optical data compression

High throughput real-time instruments are needed to acquire large data sets for detection and classification of rare events. Enabled by the photonic time stretch digitizer, a new class of instruments with record throughputs have led to the discovery of optical rogue waves [1], detection of rare cancer cells [2], and the highest analog-to-digital conversion performance ever achieved [3]. Featuring continuous operation at 100 million frames per second and shutter speed of less than a nanosecond, the time stretch camera is ideally suited for screening of blood and other biological samples. It has enabled detection of breast cancer cells in blood with record, one-in-a-million, sensitivity [2]. Owing to their high real-time throughput, instruments produce a torrent of data - equivalent to several 4K movies per second - that overwhelm data acquisition, storage, and processing operations. This predicament calls for technologies that compress images in optical domain and in real-time. An example of this, based on warped stretch transformation and non-uniform Fourier domain sampling will be reported.
Normal all pseudo-Anosov subgroups of mapping class groups

We construct the rst known examples of nontrivial, normal, all pseudo-Anosov subgroups of mapping class groups of surfaces. Specically, we construct such subgroups for the closed genus two surface and for the sphere with ve or more punctures. Using the branched covering of the genus two surface over the sphere and results of Birman and Hilden, we prove that a reducible mapping class of the genus two surface projects to a reducible mapping class on the sphere with six punctures. The construction introduces \Brunnian" mapping classes of the sphere, which are analogous to Brunnian links.
A Bayesian model of Knightian uncertainty

A long tradition suggests a fundamental distinction between situations of risk, where true objective probabilities are known, and unmeasurable uncertainties where no such probabilities are given. This distinction can be captured in a Bayesian model where uncertainty is represented by the agent’s subjective belief over the parameter governing future income streams. Whether uncertainty reduces to ordinary risk depends on the agent’s ability to smooth consumption. Uncertainty can have a major behavioral and economic impact, including precautionary behavior that may appear overly conservative to an outside observer. We argue that one of the main characteristics of uncertain beliefs is that they are not empirical, in the sense that they cannot be objectively tested to determine whether they are right or wrong. This can confound empirical methods that assume rational expectations.
Coverage control in constant flow environments based on a mixed energy-time metric

In this paper, we study a multi-vehicle coverage control problem in constant flow environments while taking into account both energy consumption and traveling time. More specifically, the metric (called the mixed energy-time metric) is a weighted sum of the energy consumption and the traveling time for a vehicle to travel from one point to another in constant flows when using the minimum energy control, and the objective is to find vehicle locations that can minimize the expected mixed energy-time required for the set of vehicles to cover a region. We propose a gradient based control law which is calculated based on refined approximated Voronoi cells (induced by the mixed energy-time metric) and of which the convergence is proved via Hybrid Systems Theory. Simulations show that the refined gradient based control can achieve similar performance as the exact gradient based control.
Minimal superstrings and loop gas models

We reformulate the matrix models of minimal superstrings as loop gas models on random surfaces. In the continuum limit, this leads to the identification of minimal superstrings with certain bosonic string theories, to all orders in the genus expansion. RR vertex operators arise as operators in a 2 twisted sector of the matter CFT. We show how the loop gas model implements the sum over spin structures expected from the continuum RNS formulation. Open string boundary conditions are also more transparent in this language.
On the definition and the construction of pockets in macromolecules

The shape of a protein is important for its functions. This includes the location and size of identifiable regions in its complement space. We formally define pockets as regions in the complement with limited accessibility from the outside. Pockets can be efficiently constructed by an algorithm based on alpha complexes. The algorithm is implemented and applied to proteins with known three-dimensional conformations.
Impact of demand response on thermal generation investment with high wind penetration

We present a stochastic programming model for investments in thermal generation capacity to study the impact of demand response (DR) at high wind penetration levels. The investment model combines continuous operational constraints and wind scenarios to represent the implications of wind variability and uncertainty at the operational level. DR is represented in terms of linear price-responsive demand functions. A numerical case study based on load and wind profiles of Illinois is constructed with 20 candidate generating units of various types. Numerical results show the impact of DR on both investment and operational decisions. We also propose a model in which DR provides operating reserves and discuss its impact on lowering the total capacity needed in the system. We observe that a relatively small amount of DR capacity is sufficient to enhance the system reliability. When compared to the case with no DR, a modest level of DR results in less wind curtailment and better satisfaction of reserve requirements, as well as improvements in both the social surplus and generator utilization, as measured by capacity factors.
Adaptive Harmonic Balance Solutions to Euler' s Equation

A new adaptive harmonic balance method is presented and applied to a variety of subsonic and supersonic onedimensional e owe elds containing strong moving shocks. The adaptive method augments the frequency content in each cell as required to capture the local e ow physics. Augmentation automatically adjusts with grid density, resulting in lower frequency content on coarse grids that cannot adequately resolve high-frequency terms. A study of the effect of augmentation thresholds, increments, and scheduling on the performance and accuracy of the adaptive method is presented, and optimal parameters identie ed. When optimal parameters are used, the new adaptive harmonic balancemethod produces solutions equivalent to a nonadapted harmonic balance solution, but with up to a 50% reduction in run time.
Spatial modeling of snow water equivalent using covariances estimated from spatial and geomorphic attributes

Abstract As the demand for water in the USA rapidly approaches the total available water supply, it is essential that water resources be accurately monitored. Consequently, the National Weather Service (NWS) maintains a set of conceptual, continuous, hydrologic simulation models used to generate extended streamflow predictions, water supply outlooks, and flood forecasts. To obtain accurate predictions and forecasts, it is necessary, periodically throughout the snow season, to estimate the snow water equivalent in river basins throughout the USA. The estimates are obtained using a geostatistical model and snow course, SNOTEL, and airborne snow data. In this research, we develop a positive-definite spatial covariance function that allows researchers to incorporate geomorphic site attributes when snow water equivalent estimates are obtained. We illustrate our approach using snow course and SNOTEL data collected in the North Fork Clearwater River basin. Our results indicate that by incorporating elevation into the covariance model used for the North Fork Clearwater River basin we are able to improve substantially the accuracy of the snow water equivalent estimates.
On the indices of curves over local fields

Fix a non-negative integer g and a positive integer I dividing 2g − 2. For any Henselian, discretely valued field K whose residue field is perfect and admits a degree I cyclic extension, we construct a curve C/K of genus g and index I. This is obtained via a systematic analysis of local points on arithmetic surfaces with semistable reduction. Applications are discussed to the corresponding problem over number fields.
The Discovery of Two Nearby Carbon Dwarfs

The comparison of optical and Two Micron All Sky Survey near-infrared photometry for large samples of cataloged proper-motion stars has given us the potential to discover previously unrecognized nearby objects of rare type. In this Letter we present the discovery of two new carbon dwarfs, LSR 2105+2514 and LP 758-43, which were drawn from proper-motion lists and which lie in a sparsely populated part of optical/near-IR color-color space. Their optical spectra, exhibiting absorptions by C2 and/or CN, are discussed. LSR 2105+2514 is believed to lie within 200 pc and would have M ≥ 6.7, making it lower in luminosity than any carbon dwarf with a measured trigonometric parallax. LP 758-43, which is not as red but still probably cooler than the best studied carbon dwarfs, is believed to lie within 360 pc. Using our optical/near-infrared selection technique on published lists of proper-motion stars, we hope in the near future to expand further the current sample of carbon dwarfs, which numbers only 31 objects at this writing.
Harmonic Balance Analysis of Limit Cycle Oscillations in Turbomachinery

A harmonic balance technique for the analysis of limit cycle oscillations of turbomachinery blades is presented. This method couples a computational fluid dynamics model to a single-degree-of-freedom structural dynamic model of the turbomachinery blades. The computational fluid dynamics solver uses a nonlinear frequency-domain (harmonic balance) approach that allows one to model the blade row of a turbomachine on a computational grid spanning a single blade passage. Using the harmonic balance approach, several solutions, each one corresponding to a different subtime level of the periodic unsteady flow, are computed simultaneously. These subtime-level solutions are coupled to each other in the computational field by a spectral approximation of the time-derivative term in the Navier―Stokes equation and also by application of far-field and periodic boundary conditions. The structural dynamic model is based on a similar approach in which a single vibratory mode of interest is modeled using the harmonic balance technique. The two solvers are coupled together through the upwash condition on the surface of the blade and the resulting generalized aerodynamic forces. In the proposed approach, the limit cycle oscillation frequency is treated as another unknown, which is solved iteratively, together with the governing equations of fluid flow and structural dynamics, thereby driving the residual of the aeroelastic problem to convergence in a single computational fluid dynamics run. The accuracy of the new method is compared with two other techniques and it is shown to offer significant computational savings.
Constraints on the Stellar Mass Function from Stellar Dynamics at the Galactic Center

We consider the dynamical evolution of a disk of stars orbiting a central black hole. In particular, we focus on the effect of the stellar mass function on the evolution of the disk, using both analytic arguments and numerical simulations. We apply our model to the ring of massive stars at 0.1 pc from the Galactic center, assuming that the stars formed in a cold, circular disk, and find that our model requires the presence of a significant population of massive (>100 M☉) stars in order to explain the observed eccentricities of 0.2-0.3. Moreover, in order to limit the damping of the heavier stars' eccentricities, we also require fewer low-mass stars than expected from a Salpeter mass function, giving strong evidence for a significantly "top-heavy" mass function in the rings of stars seen near to the Galactic center. We also note that the maximum possible eccentricities attainable from circular initial conditions at ages of <10 Myr are around 0.4-0.5, and we suggest that any rings of stars found with higher eccentricities were probably not formed from circular disks.
Insights into ground shock in jointed rocks and the response of structures there-in

Ground shock in rock masses is created by dynamic events such as rock-bursts, coal bumps or man-made explosions. This article examines two aspects of the phenomenology: the propagation of ground shock, and its effects on underground structures. Numerous experiments, at all scales, as well as numerical modeling clearly show that geologic discontinuities have a large influence on ground shock propagation through their actions as wave-guides or as decoupling features. Three-dimensional discrete element (DE) numerical models provide additional insights into the dynamic response of underground structures as influenced by joint orientation, joint spacing, characteristics of the loading pulse (duration, peak velocity, peak displacement), and repeated loadings. It is also shown that in hard rocks the deformability of rock blocks has a negligible influence on tunnel dynamic structural response compared to that of the joint sets or bedding. When viewed together with pictures of underground failures, the 3-D DE models are shown to capture quite well the kinematics of jointed rocks, and their power is illustrated through a very large simulation of an underground facility under dynamic loading.
Lattice model of amphiphilic systems: A review

Abstract A microscopic theory of amphiphilic systems is reviewed. It takes the form of a simple lattice model of three components in which one has an amphiphilic interaction with the other two. Results for the phase diagram, the scattering behavior, and the interfacial properties of the system are in qualitative agreement with experiment.
Enhancement of the traveling front speeds in reaction-diffusion equations with advection

We establish rigorous lower bounds on the speed of traveling fronts and on the bulk burning rate in reaction-diffusion equation with passive advection. The non-linearity is assumed to be of either KPP or ignition type. We consider two main classes of flows. Percolating flows, which are characterized by the presence of long tubes of streamlines mixing hot and cold material, lead to strong speed-up of burning which is linear in the amplitude of the flow, U. On the other hand the cellular flows, which have closed streamlines, are shown to produce weaker increase in reaction. For such flows we get a lower bound which grows as U1/5 for a large amplitude of the flow.
Particle statistics and whole-pattern methods in quantitative X-ray powder diffraction analysis

Modern powder diffraction employing computer-controlled diffractometers now allows quantitative analytical methods to use the whole diffraction trace rather than only individual peaks. Two such methods are in common use: the Rietveld method, which refines the crystal structures of the component phases as part of the matching calculation, and the pattern-fitting method, which uses reference patterns from a database. Potential accuracies of these methods seems to be around 1% absolute. The most severe limitation on the potential accuracy of these methods is particle statistics, which has been reviewed in considerable detail.
Distributed detection by a large team of sensors in tandem

The problem of decentralized binary hypothesis testing by a team consisting of N decision makers (DMs) in tandem is considered. Each DM receives an observation and transmits a binary message to its successor; the last DM has to decide which hypothesis is true. The necessary and sufficient condition for the probability of error to go asymptotically to zero as N to infinity is that the log-likelihood ratio of the observation of each DM be unbounded. The result is generalized for multiple hypotheses and multiple messages. An easily implementable suboptimal decision scheme is also considered; in this case, the necessary and sufficient condition for the probability of error to asymptotically go to zero is that the log-likelihood ratio of the observation of each DM be unbounded from both above and below. The tradeoff between the complexity of the decision rules and their performance is examined, and numerical results are presented, in order to demonstrate that the performance of both decision schemes is comparable. >
The rising stellar velocity dispersion of M87 from integrated starlight

We have measured the line-of-sight velocity distribution from integrated stellar light at two points in the outer halo of M87 (NGC 4486), the second-rank galaxy in the Virgo Cluster. The data were taken at R = 480'' (∼41.5 kpc) and R = 526'' (∼45.5 kpc) along the SE major axis. The second moment for a non-parametric estimate of the full velocity distribution is 420 ± 23 km s{sup –1} and 577 ± 35 km s{sup –1}, respectively. There is intriguing evidence in the velocity profiles for two kinematically distinct stellar components at the position of our pointing. Under this assumption, we employ a two-Gaussian decomposition and find the primary Gaussian having rest velocities equal to M87 (consistent with zero rotation) and second moments of 383 ± 32 km s{sup –1} and 446 ± 43 km s{sup –1}, respectively. The asymmetry seen in the velocity profiles suggests that the stellar halo of M87 is not in a relaxed state and confuses a clean dynamical interpretation. That said, either measurement (full or two component model) shows a rising velocity dispersion at large radii, consistent with previous integrated light measurements, yet significantly higher than globular cluster measurements at comparable radial positions. These integrated more » light measurements at large radii, and the stark contrast they make to the measurements of other kinematic tracers, highlight the rich kinematic complexity of environments like the center of the Virgo Cluster and the need for caution when interpreting kinematic measurements from various dynamical tracers. « less
Multiple testing of local maxima for detection of peaks in ChIP-Seq data

A topological multiple testing approach to peak detection is proposed for the problem of detecting transcription factor binding sites in ChIP-Seq data. After kernel smoothing of the tag counts over the genome, the presence of a peak is tested at each observed local maximum, followed by multiple testing correction at the desired false discovery rate level. Valid p-values for candidate peaks are computed via Monte Carlo simulations of smoothed Poisson sequences, whose background Poisson rates are obtained via linear regression from a Control sample at two different scales. The proposed method identifies nearby binding sites that other methods do not.
Massive Planet Migration: Theoretical Predictions and Comparison with Observations

We quantify the utility of large radial velocity surveys for constraining theoretical models of type II migration and protoplanetary disk physics. We describe a theoretical model for the expected radial distribution of extrasolar planets that combines an analytic description of migration with an empirically calibrated disk model. The disk model includes viscous evolution and mass loss via photoevaporation. Comparing the predicted distribution to a uniformly selected subsample of planets from the Lick, Keck, and AAT planet search programs, we find that a simple model in which planets form in the outer disk at a uniform rate, migrate inward according to a standard type II prescription, and become stranded when the gas disk is dispersed is consistent with the radial distribution of planets for orbital radii in the range 0.1 AU ≤ a 1.65 MJ. Some variant models are disfavored by existing data, but the significance is limited (~95%) due to the small sample of planets suitable for statistical analysis. We show that the favored model predicts that the planetary mass function should be almost independent of orbital radius at distances where migration dominates the massive planet population. We also study how the radial distribution of planets depends on the adopted disk model. We find that the distribution can constrain not only changes in the power-law index of the disk viscosity, but also sharp jumps in the efficiency of angular momentum transport that might occur at small radii.
Models, languages, and heuristics for distributed computing

We are interested in the issues surrounding computer problem solving in systems of loosely coupled processes. This paper is a compendium of ideas related to the software issues involved in programming distributed systems. We discuss two aspects of this problem: languages and models for distribution, and heuristics for organizing distributed systems. The second section of the paper discusses the nature of distributed languages and models, and presents a comparison of the attributes of several of the major proposals for distributed computing. The third section is a discussion of some heuristics for the organization of multiple-process systems.
Constraining the black hole mass spectrum with gravitational wave observations - I. The error kernel

Many scenarios have been proposed for the origin of the supermassive black holes (SMBHs) that are found in the centres of most galaxies. Many of these formation scenarios predict a high-redshift population of intermediate-mass black holes (IMBHs), with masses M • in the range 10 2 ≲ M • ≲ 10 5 M ⊙ A powerful way to observe these IMBHs is via gravitational waves the black holes emit as they merge. The statistics of the observed black hole population should, in principle, allow us to discriminate between competing astrophysical scenarios for the origin and formation of SMBHs. However, gravitational wave detectors such as Laser Interferometer Space Antenna (LISA) will not be able to detect all such mergers nor assign precise black hole parameters to the merger, due to weak gravitational wave signal strengths. In order to use LISA observations to infer the statistics of the underlying population, these errors must be taken into account. We describe here a method for folding the LISA gravitational wave parameter error estimates into an 'error kernel' designed for use at the population model level. The effects of this error function are demonstrated by applying it to several recent models of black hole mergers, and some tentative conclusions are made about LISA's ability to test scenarios of the origin and formation of SMBHs.
Outcomes of Medicare Beneficiaries With Heart Failure and Atrial Fibrillation

Objectives This study sought to examine the long-term outcomes of patients hospitalized with heart failure and atrial fibrillation. Background Atrial fibrillation is common among patients hospitalized with heart failure. Associations of pre-existing and new-onset atrial fibrillation with long-term outcomes are unclear. Methods We analyzed 27,829 heart failure admissions between 2006 and 2008 at 281 hospitals in the American Heart Association9s Get With The Guidelines–Heart Failure program linked with Medicare claims. Patients were classified as having pre-existing, new-onset, or no atrial fibrillation. Cox proportional hazards models were used to identify factors that were independently associated with all-cause mortality, all-cause readmission, and readmission for heart failure, stroke, and other cardiovascular disease at 1 and 3 years. Results After multivariable adjustment, pre-existing atrial fibrillation was associated with greater 3-year risks of all-cause mortality (hazard ratio [HR]: 1.14 [99% confidence interval (CI): 1.08 to 1.20]), all-cause readmission (HR: 1.09 [99% CI: 1.05 to 1.14]), heart failure readmission (HR: 1.15 [99% CI: 1.08 to 1.21]), and stroke readmission (HR: 1.20 [99% CI: 1.01 to 1.41]), compared with no atrial fibrillation. There was also a greater hazard of mortality at 1 year among patients with new-onset atrial fibrillation (HR: 1.12 [99% CI: 1.01 to 1.24]). Compared with no atrial fibrillation, new-onset atrial fibrillation was not associated with a greater risk of the readmission outcomes. Stroke readmission rates at 1 year were just as high for patients with preserved ejection fraction as for patients with reduced ejection fraction. Conclusions Both pre-existing and new-onset atrial fibrillation were associated with greater long-term mortality among older patients with heart failure. Pre-existing atrial fibrillation was associated with greater risk of readmission.
HYBRID SIMULATED ANNEALING AND CASE-BASED REASONING APPROACH FOR COMPUTATIONALLY INTENSIVE TRANSPORTATION PROBLEMS: RATIONALE AND DESIGN ISSUES

A hybrid artificial intelligence approach based on combining simulated annealing (SA) and case-based reasoning (CBR) is presented. The approach is designed to allow for solving complex, time-critical optimization problems, examples of which lie at the heart of several intelligent transportation systems applications. According to this hybrid approach, the system, when faced with a new problem, first accesses the case base and attempts to locate a sufficiently similar case. If such a case can be located, the solution of the CBR-retrieved case is directly reused. If not, the SA algorithm is used to solve the problem, with the solution of the CBR-retrieved case serving as a starting point for the search algorithm. The rationale behind the approach is discussed, and its major design issues are analyzed. A case study is then presented to illustrate how the approach could be designed and to demonstrate its advantages. Results indicate that combining SA and CBR offers an efficient approach to solving complex, tim...
Acoustic effect and correlated errors in soliton information transmission.

The acoustic effect significantly increases the timing jitter of solitons in communication lines. We calculate the correlation in near-neighbor soliton time shifts that result from the acoustic interaction and show that the acoustic effect can cause correlated errors that cannot be corrected with standard, simple error-correction codes such as the Hamming code.
Fission Product Monitoring of TRISO Coated Fuel For The Advanced Gas Reactor -1 Experiment

The US Department of Energy has embarked on a series of tests of TRISO coated particle reactor fuel intended for use in the Very High Temperature Reactor (VHTR) as part of the Advanced Gas Reactor (AGR) program. The AGR-1 TRISO fuel experiment, currently underway, is the first in a series of eight fuel tests planned for irradiation in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The AGR-1 experiment reached a peak compact averaged burnup of 9% FIMA with no known TRISO fuel particle failures in March 2008. The burnup goal for the majority of the fuel compacts is to have a compact averaged burnup greater than 18% FIMA and a minimum compact averaged burnup of 14% FIMA. At the INL the TRISO fuel in the AGR-1 experiment is closely monitored while it is being irradiated in the ATR. The effluent monitoring system used for the AGR-1 fuel is the Fission Product Monitoring System (FPMS). The FPMS is a valuable tool that provides near real-time data indicative of the AGR-1 test fuel performance and incorporates both high-purity germanium (HPGe) gamma-ray spectrometers and sodium iodide [NaI(Tl)] scintillation detector-based gross radiation monitors. To quantify the fuel performance, release-to-birth ratios (R/B's) of radioactive fission gases are computed. The gamma-ray spectra acquired by the AGR-1 FPMS are analyzed and used to determine the released activities of specific fission gases, while a dedicated detector provides near-real time count rate information. Isotopic build up and depletion calculations provide the associated isotopic birth rates. This paper highlights the features of the FPMS, encompassing the equipment, methods and measures that enable the calculation of the release-to-birth ratios. Some preliminary results from the AGR-1 experiment are also presented.
Toward a multi-path approach for SETI

Abstract The concept of “the plurality of worlds” has been with us from the days of Ancient Greece, but only in the 19th century did we begin to consider practical means of communication, none of which, however, was implemented. In the second half of the 20th century, the advent of the space era made possible the actual search for extraterrestrial life in our solar system, and the development of radio astronomy made possible the search for radio signals from other advanced civilizations in our galaxy. It is interesting to note that our ideas about possible modes of communication have evolved hand in hand with technology and are progressively expanding toward broader concepts. Therefore, a multi-path approach for SETI appears to be a wiser strategy towards a complex problem, for which it is very difficult to predict with certainty the means and the time that other stellar civilizations (if they do exist) will select to contact us.
Spontaneous Raman scattering as a high-resolution XUV radiation source

The paper describes a new type of high-resolution XUV radiation source which is based upon spontaneous anti-Stokes scattering of tunable incident laser radiation from atoms excited to metastable levels. The theory of the source is summarized and two sets of experiments using He ( 1s2s )1S atoms, produced in a CW hollow cathode and in a pulsed high-power microwave discharge, are discussed. The radiation source is used to examine transitions originating from the 3p6shell of potassium. The observed features include four previously unreported absorption lines and several sharp interferences of closely spaced autoionizing lines. A source linewidth of about 1.9 cm-1at 185 000 cm-1is demonstrated.
Setting the Stage for Habitable Planets

Our understanding of the processes that are relevant to the formation and maintenance of habitable planetary systems is advancing at a rapid pace, both from observation and theory. The present review focuses on recent research that bears on this topic and includes discussions of processes occurring in astrophysical, geophysical and climatic contexts, as well as the temporal evolution of planetary habitability. Special attention is given to recent observations of exoplanets and their host stars and the theories proposed to explain the observed trends. Recent theories about the early evolution of the Solar System and how they relate to its habitability are also summarized. Unresolved issues requiring additional research are pointed out, and a framework is provided for estimating the number of habitable planets in the Universe.
Experimental Feedback Control of Flow-Induced Cavity Tones

Discrete-time, linear quadratic methods were used to design feedback controllers for reducing tones generated by flow over a cavity. The dynamics of a synthetic jet actuator mounted at the leading edge of the cavity as observed by two microphones in the cavity were modeled over a broad frequency range using state space models computed from experimental data. Variations in closed loop performance as a function of model order, control order, control bandwidth, and state estimator design were studied using a cavity in the Probe Calibration Tunnel at NASA Langley. The controller successfully reduced the levels of multiple cavity tones at the tested flow speeds of Mach 0.275, 0.35, and 0.45. In some cases, the closed loop results were limited by excitation of sidebands of the cavity tones, or the creation of new tones at frequencies away from the cavity tones. Nonetheless, the results validate the combination of optimal control and experimentally-generated state space models, and suggest this approach may be useful for other flow control problems. The models were not able to account for non-linear dynamics, such as interactions between tones at different frequencies.
Acquiring a Variable Structure: An Interlanguage Analysis of Second Language Mood Use in Spanish

This investigation connects issues in second language (L2) acquisition to topics in quantitative sociolinguistics by exploring the relationship between native-speaker (NS) and L2 variation. It is the first large-scale analysis of L2 mood use (the subjunctive-indicative contrast) in Spanish. It applies variationist findings on the range of linguistic and extralinguistic factors (form regularity, semantic category, time reference, hypotheticality, and task) shown to influence NSs’ mood use to an interlanguage analysis of L2 development and shows that analyses of frequency and predictors provide revealing details about how learners acquire the ability to vary their use of verbal moods in Spanish. Variationism, it is concluded, can foster rich descriptions and explanations of interlanguage and its evolution.
Impedance-Based Modeling of Actuators Bonded to Shell Structures:

When discrete piezoelectric actuator patches bonded on structures are used for active shape, vibration, and acoustic control, the desired deformation field in the structure is obtained through the application of localized line forces and moments generated by expanding or contracting bonded piezoelectric actuators. An impedance-based model to predict the dynamic response of cylindrical shells subjected to excitation from surface-bonded induced strain actuators is presented. The essence of the impedance approach is to match the actuator impedance with the structural impedance at the ends of the actuators, which will retain the dynamic characteristics of the actuators. A detailed derivation of the actuator and structural impedance is included. It is found that the actuator's output dynamic force in the axial and tangential direction are not equal. Various case studies of a cylindrical thin shell are performed to illustrate the capabilities of the developed impedance model. Out-of-phase actuation is shown to ...
Effect of a targeted education intervention on the incidence of waste-burning injuries in a military population.

The burning of waste is a common cause of accidental injury on the battlefield. This study was devised to determine the incidence of burns incurred while burning waste during U.S. military operations prior to and following an intervention targeted at reducing such injuries. The intervention consisted of a memoranda outlining potential dangers and suggesting improved safety procedures. It was distributed to the combat theater (Iraq and Afghanistan) in March 2004. We reviewed military burn center records from March 2003 to March 2005. Demographics, injury data, and outcomes were recorded and compared between those casualties injured prior to and following the initiative. Twenty-four patients were injured while burning waste, 10% of military casualties admitted to the burn center during the study period. From March 2003 to March 2004, 20 patients were admitted with such injuries. The incidence of 1.67 per month was significantly (P Language: en
Highly transient elastodynamic crack growth in a bimaterial interface : higher order asymptotic analysis and optical experiments

Abstract A higher Order asymptotic analysis of the transient deformation field surrounding the tip of a crack running dynamically along a bimaterial interface is presented. An asymptotic methodology is used to reduce the problem to one of the Riemann-Hilbert type. Its solution furnishes displacement potentials which are used to evaluate explicitly the near-tip transient stress field. Crack-tip fields corresponding to crack speeds up to the lower of the two shear wave speeds are investigated. An experimental study of dynamic crack growth in PMMA steel interfaces using the optical method of CGS and high speed photography, is also described. Transonic terminal speeds (up to 1.4cPMMAS) and initial accelerations ( $ 108 ms2) are reported and discussed. Transient effects are found to be severe and more important than in homogeneous dynamic fracture. For subsonic crack growth, these experiments arc used to demonstrate the necessity of employing a fully transient expression in the analysis of optical data to predict accurately the complex dynamic stress intensity factor history.
Solitary waves in stratified fluids and their interaction

A systematic procedure is proposed for obtaining solutions for solitary waves in stratified fluids. The stratification of the fluid is assumed to be exponential or linear. Its comparison with existing results for an exponentially stratified fluid shows agreement, and it is found that for the odd series of solutions the direction of displacement of the streamlines from their asymptotic levels is reversed when the stratification is changed from exponential to linear. Finally the interaction of solitary waves is considered, and the Korteweg-de Vries equation and the Boussinesq equation are derived. Thus the known solutions of these equations can be relied upon to provide the answers to the interaction problem.
Constrained multi-item inventory systems: an implicit approach

Abstract This paper examines the n -item deterministic inventory model subject to a single linear constraint. Functional relationships between the Lagrangian multipliers and shifts occurring simultaneously in multiple system parameters are identified and used to establish effective initial bounds on the optimal multiplier value in closed form. A recursive process which rapidly converges to the optimal Lagrangian multiplier is also presented. Finally, a comparative analysis highlighting the efficienty of the proposed process in relation to existing algorithms is exhibited.
Counting Rational Points on K3 Surfaces

Abstract For any algebraic variety X defined over a number field K , and height function H D on X corresponding to an ample divisor D , one can define the counting function N X , D ( B )=#{ P ∈ X ( K ) ∣ H D ( P )⩽ B }. In this paper, we calculate the counting function for hyperelliptic K 3 surfaces X which admit a generically two-to-one cover of P 1 × P 1 branched over a singular curve. In particular, we effectively construct a finite union Y =∪ C i of curves C i ⊂ X such that N X − Y , D ( B )⪡ N Y , D ( B ); that is, Y is an accumulating subset of X . In the terminology of Batyrev and Manin [4], this amounts to proving that Y is the first layer of the arithmetic stratification of X . We prove a more precise result in the special case where X is a Kummer surface whose associated Abelian surface is a product of elliptic curves.
Adsorption of normal alkanes on Hg: Experimental check of gibbs adsorption equation and theoretical contact potential

Abstract Simultaneous surface tension, contact potential, and ellipsometric measurements of pentane, octadecane, and dotriacotane on mercury have been made at 24°C. These measurements for pentane have been used to experimentally verify the Gibbs adsorption equation within 6%. It is demonstrated that the experimental contact potential and dielectric constant of the adsorbed films can be theoretically predicted over the range of adsorption (Γ = 0 to 5.5 × 1014 molecules/cm2) with no adjustable parameters. the electric field 2.1 Λ above a clean mercury surface is 1.35 × 107 volts/cm. The dipole moment induced in CH bounds by the electric field is 0.0292 D per CH if the chain is parallel to the surface. The eneregy to change molecules from a horizontal orientation to a vertical orientation is equal to the difference between the heat of adsorption on Hg and the heat of vaporization from the liquid alkane. This energy per CH bond proves to be 0.15 × 10−13 ergs. A most probable model for molecular orientation is revealed as a function of surface density.
Model modification in structural equation modeling by imposing constraints

Two approaches for model modification, or specification search, in structural equation modeling are: releasing constraints (e.g., adding free parameters) and imposing constraints (e.g., deleting free parameters). These two approaches can be considered as "forward search" and "backward search", respectively. The forward search approach, which starts with a more limited model to find a more general model by adding free parameters, is very frequently utilized in practice. However, the success rate of the forward approach in obtaining the correct model is usually low. The forward search also has been found to depend very highly on the initial model selected in the modification process. The farther the initial model differs from the true model, the less likely is the proper modification to occur. This study illustrates the backward search approach, which starts with a more general model and improves the model by imposing constraints, using the z and Wald (W) tests. Assuming a correct measurement model, this study focuses on the model modification of structural relationships among factors. The results showed that with correct specification of the causal order of latent factors the correct model may be located with higher than 60% accuracy, using the incremental univariate Wald test, or the z test. With more cautious, or restricted, search, the success rates are even higher.
Developing an expert ship message interpreter: theoretical and practical conclusions

The architecture of the control and data structures of the real-time expert system ERIK ("evaluating reports using integrated knowledge") is fine tuned for the task of flexible knowledge-intensive interpretation of ship messages. In spite of the large amounts of knowledge needed for this interpretation task, ERIK can interpret noisy and ill-formed inputs with high reliability due to a variety of computational features. Among these features are an expectation-driven control structure, selective variable depth focusing of attention, intelligent recovery from failed expectations, distributed recognition modules, and a sophisticated spelling correction facility. ERIK, which is now running on-line at the Coast Guard Automated Mutual-assistance Vessel Rescue (AMVER) center, incorporates artificial intelligence design and programming techniques. Using these techniques to solve a complex real-time information processing problem has led to theoretical and practical insights that are presented in this paper.
Pauli-limited superconductivity in small grains

We report on an exploration of the mean-field phase diagram for Pauli-limited superconductivity in small metallic grains. Emphasis is placed on the crossover from the ultra-small grain limit where superconductivity disappears to the bulk thin-film limit as the single-particle level spacing in the grain decreases. We find that the maximum Zeeman coupling strength compatible with superconductivity increases with decreasing grain size, in spite of a monotonically decreasing condensation energy per unit volume.
The Response of the Zonally Averaged Circulation to Stratospheric Ozone Reductions.

The effects of various ozone density reductions of the zonally averaged circulation are evaluated with a numerical quasi-geostrophic model. If the ozone perturbations are confined to the polar regions and are minuscule on a global basis as was characteristic of the August 1972 solar proton event, then the calculations indicate a negligible effect on the mean circulation. For global ozone perturbations by predicted halocarbon pollution, about 10% reduction in the zonal jet strength and less than a 5% change in global mean stratospheric temperature are calculated. Large, uniform ozone reductions (above 50%) produce significant effects on the mean circulation: a substantial collapse of the stratosphere due to cooler temperatures, and a weak polar night jet. The reflection and transmission of quasi-stationary planetary waves in the middle atmosphere are computed to be insensitive to solar activity as extreme as the August 1972 solar proton event. It thus seems improbable that planetary waves are a viable mechanism for solar-weather interactions that involve perturbations of the zonally averaged circulation by ozone density reductions.
Synthesis, structure and magnetic properties of A2MnB′O6 (A=Ca, Sr; B′=Sb, Ta) double perovskites

A2MnB 0 O6 (A ¼ Ca, Sr; B ¼ Sb, Ta) double perovskites have been synthesized and their structural and magnetic properties have been investigated. Rietveld refinement of the powder X-ray diffraction data for Sr2MnSbO6 indicated significant ordering of Mn and Sb at the B-site while all other phases showed mostly a random distribution of the B-site cations. X-ray absorption spectroscopic data established the presence of Mn in the 3+ and Sb/Ta in the 5+ oxidation states in all the phases. Magnetic susceptibility data indicated ferromagnetic correlations for all the A2MnB 0 O6 phases with Weiss temperatures varying from 64 to 107 K.
Nickel-catalyzed reductive arylation of activated alkynes with aryl iodides.

Abstract The direct, regioselective, and stereoselective arylation of activated alkynes with aryl iodides using a nickel catalyst and manganese reductant is described. The reaction conditions are mild (40 °C in MeOH, no acid or base) and an intermediate organomanganese reagent is unlikely. Functional groups tolerated include halides and pseudohalides, free and protected anilines, and a benzyl alcohol. Other activated alkynes including an amide and a ketone also reacted to form arylated products in good yields.