cssi/SciSciGPT-SciSciNet huggingface dataset:
Infrared spectra of M(OH)(1,2,4) (M = Pb, Sn) in solid argon.

Infrared absorptions for the matrix-isolated lead and tin hydroxides M(OH), M(OH)2 and M(OH)4 (M = Pb, Sn) were observed in laser-ablated metal atom reactions with H2O2 during condensation in excess argon. The major M(OH)2 product was also observed with H2 and O2 mixtures, which allowed the substitution of 18O2. The band assignments were confirmed by appropriate D2O2, D2, 16O18O, and 18O2 isotopic shifts. MP2 and B3LYP calculations were performed to obtain molecular structures and to reproduce the infrared spectra. The minimum energy structure found for M(OH)2 has Cs symmetry and a weak intramolecular hydrogen bond. In experiments with Sn, HD, and O2, the internal D bond is favored over the H bond for Sn(OH)(OD). The Pb(OH)4 and Sn(OH)4 molecules are calculated to have S4 symmetry and substantial covalent character.
Impedance matched absorptive thermal blocking filters

We have designed, fabricated, and characterized absorptive thermal blocking filters for cryogenic microwave applications. The transmission line filter's input characteristic impedance is designed to match 50 Ω and its response has been validated from 0 to 50 GHz. The observed return loss in the 0 to 20 GHz design band is greater than 20 dB and shows graceful degradation with frequency. Design considerations and equations are provided that enable this approach to be scaled and modified for use in other applications.
Dynamic Topology Optimization of Compliant Mechanisms and Piezoceramic Actuators

A topology optimization method is developed to design a piezoelectric ceramic actuator together with a compliant mechanism coupling structure for dynamic applications. The objective is to maximize the mechanical efficiency with a constraint on the capacitance of the piezoceramic actuator. Examples are presented to demonstrate the effect of considering dynamic behavior compared to static behavior and the effect of sizing the piezoceramic actuator on the optimal topology and the capacitance of the actuator element. Comparison studies are also presented to illustrate the effect of damping, external spring stiffness, and driving frequency. The optimal topology of the compliant mechanism is shown to be dependent on the driving frequency, the external spring stiffness, and whether the piezoelectric actuator element is considered design or nondesign. At high driving frequencies, it was found that the dynamically optimized structure is very near resonance.
On the Spatial Distribution of Stellar Populations in the Large Magellanic Cloud

We measure the angular correlation function of stars in a region of the Large Magellanic Cloud (LMC) that spans 20 × 15. We find that the correlation functions of stellar populations are represented well by exponential functions of the angular separation for separations between 2' and 40' (corresponding to ~30 and 550 pc for an LMC distance of 50 kpc). The inner boundary is set by the presence of distinct, highly correlated structures, which are the more familiar stellar clusters, and the outer boundary is set by the observed region's size and the presence of two principal centers of star formation within the region. We also find that the normalization and scale length of the correlation function changes systematically with the mean age of the stellar population. The existence of positive correlation at large separations (~300 pc), even in the youngest population, argues for large-scale hierarchical structure in current star formation. The evolution of the angular correlation toward lower normalizations and longer scale lengths with stellar age argues for the dispersion of stars with time. We show that a simple, stochastic, self-propagating star formation model is qualitatively consistent with this behavior of the correlation function.
Evolution of helium isotopes in the Earth's mantle

Degassing of the Earth's mantle through magmatism results in the irreversible loss of helium to space, and high 3He/4He ratios observed in oceanic basalts have been considered the main evidence for a ‘primordial’ undegassed deep mantle reservoir. Here we present a new global data compilation of ocean island basalts, representing upwelling ‘plumes’ from the deep mantle, and show that island groups with the highest primordial signal (high 3He/4He ratios) have striking chemical and isotopic similarities to mid-ocean-ridge basalts. We interpret this as indicating a common history of mantle trace element depletion through magmatism. The high 3He/4He in plumes may thus reflect incomplete degassing of the deep Earth during continent and ocean crust formation. We infer that differences between plumes and the upper-mantle source of ocean-ridge basalts reflect isolation of plume sources from the convecting mantle for ∼1–2 Gyr. An undegassed, primordial reservoir in the mantle would therefore not be required, thus reconciling a long-standing contradiction in mantle dynamics. Degassing of the Earth's mantle through magmatism results in the irreversible loss of helium to space. As virtually all Earth's 3He is ‘primordial’, high 3He/4He ratios in ocean island basalts are generally taken as evidence for a primitive, unmelted reservoir in the deep Earth. A new global data compilation now shows that ocean island basalts displaying the strongest primordial signal are chemically and isotopically most like mid-ocean-ridge basalts, indicating a common melting history for continent and ocean crust formation via incomplete degassing. This suggests that there is no primordial undegassed reservoir of helium in the mantle, reconciling a long-standing paradox in mantle dynamics.
The degenerate analogue of Ariki’s categorification theorem

We explain how to deduce the degenerate analogue of Ariki’s categorification theorem over the ground field $${\mathbb{C}}$$ as an application of Schur–Weyl duality for higher levels and the Kazhdan–Lusztig conjecture in finite type A. We also discuss some supplementary topics, including Young modules, tensoring with sign, tilting modules and Ringel duality.
Low-Pressure Plasma Spectroscopic Diagnostics

Diagnostic techniques have recently been developed that permit the determination of the deviation from local thermal equilibrium (LTE) in subatmospheric electric arcs and plasma jets. A review is presented of the methods that are applicable to MPD (magnetoplasmadynamic) and arcjet thruster plasmas but that have not been used in space propulsion research. Appropriate plasma diagnostics can lead to increased thrust, better nozzle design, and improved modeling capabilities. These methods include nonintrusive techniques, and can determine the electron, Te, gas, Tg, and total excitation, Texa< temperatures, as well as the electron and atom densities, without using LTE or partial LTE assumptions. General relations for analysis and experimental results for argon constricted arcs, an arc in a rotating magnetic field, and plasma torch jets are presented. The methods discussed can also be applied to plasma mixtures.
Studying dark energy with galaxy cluster surveys

Abstract Galaxy cluster surveys provide a powerful means of studying the density and nature of the dark energy. The redshift distribution of detected clusters in a deep, large solid angle SZE or X-ray survey is highly sensitive to the dark energy equation of state. Accurate constraints at the 5% level on the dark energy equation of state require that systematic biases in the mass estimators must be controlled at better than the ∼10% level. Observed regularity in the cluster population and the availability of multiple, independent mass estimators suggests these precise measurements are possible. Using hydrodynamical simulations that include preheating, we show that the level of preheating required to explain local galaxy cluster structure has a dramatic effect on X-ray cluster surveys, but only a mild effect on SZE surveys. This suggests that SZE surveys may be optimal for cosmology while X-ray surveys are well suited for studies of the thermal history of the intracluster medium.
Using NBS as a Mild Bromination Reagent for Polyalkoxyaromatic Systems

Abstract N-Bromosuccinimide in Methylene Chloride is A Mild Mono- or Di-bromination Reagent for Polyalkoxyaromatic Compounds Including Those Which are too Labile to be Brominated with Molecular Bromine.
Quantum superalgebras at roots of unity and non-Abelian symmetries of integrable models

We consider integrable vertex models whose Boltzmann weights (R-matrices) are trigonometric solutions to the graded Yang–Baxter equation. As is well known, the latter can be generically constructed from quantum affine superalgebras Uq(ĝ). These algebras do not form a symmetry algebra of the model for generic values of the deformation parameter q when periodic boundary conditions are imposed. If q is evaluated at a root of unity we demonstrate that in certain commensurate sectors one can construct non-Abelian subalgebras which are translation invariant and commute with the transfer matrix and therefore with all charges of the model. In the line of argument, we introduce the restricted quantum superalgebra Uresq(ĝ) and investigate its root of unity limit. We prove several new formulae involving supercommutators of arbitrary powers of the Chevalley–Serre generators and derive higher order quantum Serre relations as well as an analogue of Lustzig's quantum Frobenius theorem for superalgebras.
An optimal deterministic algorithm for online b -matching

Abstract We consider the natural online version of the well-known unweighted b -matching problem. We present a deterministic algorithm B ALANCE whose competitive ratio is 1−1/(1+1/b) a , where a is the number of online servers per site, and b is the number of adversarial servers per site. We show that the competitive ratio of every deterministic online algorithm is at least 1−1/(1+1/b) a . Hence, B ALANCE is optimally competitive, including low-order terms. In the case a=b , the competitive ratio of B ALANCE approaches 1−1/e≈0.63 as b grows.
Analyzing the Relationships among Race, Wealth, and Home Ownership in America

Abstract This paper presents new evidence on the determinants of the large disparities in home ownership by race in the U.S. Consistent with results first reported by P. Linneman and S. M. Wachter (1989,AREOFA J.7, No. 4, 389–402), we find noceteris paribusracial differences in ownership rates among white and minority households who possess sufficient wealth to meet down payment and closing cost requirements associated with standard mortgage underwriting criteria. However, substantial racial differences among wealth-constrained households exist, with constrained whites owning at higher rates than observationally equivalent minority households. Because minorities are disproportionately constrained by wealth-related underwriting standards, these differentials apply to roughly one-third of the white households in our samples and well over one-half of the minority sample. A multinomial model that treats central city versus suburban location as a choice variable in addition to tenure status is also estimated. The results show that even among households unconstrained by wealth-related underwriting considerations, minorities are much more likely than whites to own in central city locations. Thus, while controlling for wealth constraint status does eliminate tenure choice differences among the unconstrained, location differences remain for this group. They also are present among constrained households. Given the disparate fortunes of central city and suburban land markets in many metropolitan areas, this racial location pattern of ownership may have important long-run impacts on wealth distribution by race.
An efficient algorithm for finding a path subject to two additive constraints

One of the key issues in providing end-to-end quality-of-service (QoS) guarantees in packet networks is how to determine a feasible path that satisfies a number of QoS constraints. For two or more additive constraints, the problem of finding a feasible path is NP-complete that cannot be exactly solved in polynomial time. Accordingly, several heuristics and approximation algorithms have been proposed for this problem. Many of these algorithms suffer from either excessive computational cost or low performance. In this paper, we provide an efficient approximation algorithm for finding a path subject to two additive constraints. The worst-case computational complexity of this algorithm is within a logarithmic number of calls to Dijkstra's shortest path algorithm. Its average complexity is even much lower than that, as demonstrated by simulation experiments. The performance of the proposed algorithm is justified via theoretical bounds that are provided for the optimal version of the path selection problem. To achieve further performance improvement, several extensions to the basic algorithm are also provided at very low computational cost. Extensive simulations are used to demonstrate the high performance of the proposed algorithm and to contrast it with other path selection algorithms.
The coagulant and thrombogenic properties of human atheroma.

Suspensions of gruel from severely atherosclerotic human aortas and coronary arteries were tested in several coagulation systems. The atheromatous material shortened the clotting time of normal whole blood and plasma and accelerated thrombus formation time in the Chandler apparatus. Normal human platelets in platelet-rich plasma were aggregated by the atheromatous gruel. Aggregation did not occur when the gruel was added to platelet-rich plasma from a patient with a severe factor XII (Hageman) deficiency. The intravenous injection of atheromatous plaque suspensions into rats caused thrombocytopenia, shortening of the whole blood clotting time, and thrombosis. Coagulation of blood from patients with classical hemophilia, with Hageman factor deficiency, and with coumarin-induced anticoagulant effect was accelerated by the addition of the atheromatous gruel. Blood from patients given heparin, however, largely retained its anticoagulant activity. Atheromatous material from both aortic and coronary arteries be...
Controlling the size of popcorn

Abstract We present a thermo-statistical model of popcorn production and propose a way to control the final size of the popcorn by monitoring only the chamber pressure.
Semisimple Orbits of Lie Algebras and Card-Shuffling Measures on Coxeter Groups

Abstract Random walk on the chambers of hyperplane arrangements is used to define a family of card shuffling measures H W , x for a finite Coxeter group W and real x ≠ 0. By algebraic group theory, there is a map Φ from the semisimple orbits of the adjoint action of a finite group of Lie type on its Lie algebra to the conjugacy classes of the Weyl group. Choosing such a semisimple orbit uniformly at random thereby induces a probability measure on the conjugacy classes of the Weyl group. For types A , B , and the identity conjugacy class of W for all types, it is proved that for q very good, this measure on conjugacy classes is equal to the measure arising from H W , q . The possibility of refining Φ to a map to elements of the Weyl group is discussed.
Performance modeling of communication and computation in hybrid MPI and OpenMP applications

Abstract Performance evaluation and modeling are crucial steps to enabling the optimization of parallel programs. Programs written using two programming models, such as MPI and OpenMP, require analysis to determine both performance efficiency and the most suitable numbers of processes and threads for their execution on a given platform. To study both of these problems, we propose the construction of a model that is based upon a small number of parameters, but is able to capture the complexity of the runtime system. We incorporate measurements of overheads introduced by each of the programming models, and thus need to model both the network and computational aspects of the system. We have combined two different techniques that includes static analysis, driven by the OpenUH compiler, to retrieve application signatures and a parallelization overhead measurement benchmark, realized by Sphinx and Perfsuite, to collect system profiles. Finally, we propose a performance evaluation measurement to identify communication and computation efficiency. In this paper, we describe our underlying framework, the performance model, and show how our tool can be applied to a sample code.
Oscillation and recoil of single and consecutively printed droplets.

In this study, the recoil and oscillation of single and consecutively printed drops on substrates of different wettabilities are examined using a high speed camera. The results show that, for a droplet impact on a dry surface at Weber number ∼ O (1), both inertia and capillary effects are important in the initial spreading regime before the droplet starts to oscillate. For a substrate of higher wettability, drop oscillation decays faster due to a stronger viscous dissipation over a longer oscillation path parallel to the substrate. It is also found that when a drop impacts on a sessile drop sitting on a hydrophobic substrate, the combined drop recoil twice resulted from the coalescence of the two drops, whereas no recoil is observed for the impact of a single drop on a dry surface under the same condition. Furthermore, a single-degree-of-freedom vibration model for the height oscillation of single and combined drops on a hydrophobic substrate is established. For the condition considered, the model predict...
The kinetic energy density in Kohn–Sham density functional theory

Abstract This work continues a program to systematically generalize the Skyrme Hartree–Fock method for medium and heavy nuclei by applying effective field theory (EFT) methods to Kohn–Sham density functional theory (DFT). When conventional Kohn–Sham DFT for Coulomb systems is extended beyond the local density approximation, the kinetic energy density τ is sometimes included in energy functionals in addition to the fermion density. However, a local (semi-classical) expansion of τ is used to write the energy as a functional of the density alone, in contrast to the Skyrme approach. The difference is manifested in different single-particle equations, which in the Skyrme case include a spatially varying effective mass. Here we show how to generalize the EFT framework for DFT derived previously to reconcile these approaches. A dilute gas of fermions with short-range interactions confined by an external potential serves as a model system for comparisons and for testing power-counting estimates of new contributions to the energy functional.
Verbal subgroups of hyperbolic groups have infinite width

Let $G$ be a non-elementary hyperbolic group. Let $w$ be a group word such that the set $w[G]$ of all its values in $G$ does not coincide with $G$ or 1. We show that the width of verbal subgroup $w(G)= $ is infinite. That is, there is no such $l\in\mathbb Z$ that any $g\in w(G)$ can be represented as a product of $\le l$ values of $w$ and their inverses.
A microphysiological system model of therapy for liver micrometastases

Metastasis accounts for almost 90% of cancer-associated mortality. The effectiveness of cancer therapeutics is limited by the protective microenvironment of the metastatic niche and consequently these disseminated tumors remain incurable. Metastatic disease progression continues to be poorly understood due to the lack of appropriate model systems. To address this gap in understanding, we propose an all-human microphysiological system that facilitates the investigation of cancer behavior in the liver metastatic niche. This existing LiverChip is a 3D-system modeling the hepatic niche; it incorporates a full complement of human parenchymal and non-parenchymal cells and effectively recapitulates micrometastases. Moreover, this system allows real-time monitoring of micrometastasis and assessment of human-specific signaling. It is being utilized to further our understanding of the efficacy of chemotherapeutics by examining the activity of established and novel agents on micrometastases under conditions replicating diurnal variations in hormones, nutrients and mild inflammatory states using programmable microdispensers. These inputs affect the cues that govern tumor cell responses. Three critical signaling groups are targeted: the glucose/insulin responses, the stress hormone cortisol and the gut microbiome in relation to inflammatory cues. Currently, the system sustains functioning hepatocytes for a minimum of 15 days; confirmed by monitoring hepatic function (urea, α-1-antitrypsin, fibrinogen, and cytochrome P450) and injury (AST and ALT). Breast cancer cell lines effectively integrate into the hepatic niche without detectable disruption to tissue, and preliminary evidence suggests growth attenuation amongst a subpopulation of breast cancer cells. xMAP technology combined with systems biology modeling are also employed to evaluate cellular crosstalk and illustrate communication networks in the early microenvironment of micrometastases. This model is anticipated to identify new therapeutic strategies for metastasis by elucidating the paracrine effects between the hepatic and metastatic cells, while concurrently evaluating agent efficacy for metastasis, metabolism and tolerability.
High-density Two-Dimensional Small Polaron Gas in a Delta-Doped Mott Insulator

Heterointerfaces in complex oxide systems open new arenas in which to test models of strongly correlated material, explore the role of dimensionality in metal-insulator-transitions (MITs) and small polaron formation. Close to the quantum critical point Mott MITs depend on band filling controlled by random disordered substitutional doping. Delta-doped Mott insulators are potentially free of random disorder and introduce a new arena in which to explore the effect of electron correlations and dimensionality. Epitaxial films of the prototypical Mott insulator GdTiO3 are delta-doped by substituting a single (GdO)+1 plane with a monolayer of charge neutral SrO to produce a two-dimensional system with high planar doping density. Unlike metallic SrTiO3 quantum wells in GdTiO3 the single SrO delta-doped layer exhibits thermally activated DC and optical conductivity that agree in a quantitative manner with predictions of small polaron transport but with an extremely high two-dimensional density of polarons, ~7 × 1014 cm−2.
Fuel Injection Scheme for a Compact Afterburner Without Flameholders

State of the art afterburner combustion employs spray bars and flameholders in a long cavity, which adds significant length and weight to the engine and increases its observability. This paper presents a feasibility study for the development of a compact “prime and trigger” afterburner that eliminates the flameholders and reduces the length of the engine. In this concept, fuel is injected just upstream or in between the turbine stages in such a manner that upon exiting the turbine the fuel has evaporated and premixed with the flow without significant combustion, a process referred to as “priming”. Downstream of the turbine, combustion is initiated either through autoignition or by using a low power plasma radical generator being developed in a parallel investigation to “trigger” the combustion process. The prime and trigger injection and ignition scheme has been investigated using an experimental setup that simulates the operating conditions in a typical gas turbine engine. For this investigation, a trigger is not used, and combustion of the fuel occurs through autoignition. A physics-based theoretical model was developed to predict the location of autoignition for given flow and spray properties and injection locations. The theoretical predictions and the experimental results obtained using thermocouple measurements and CH* chemiluminescence confirm the feasibility of the prime and trigger concept by demonstrating the predictable and controlled autoignition of the afterburner fuel.Copyright © 2007 by ASME
Disc morphogenesis in vertebrate photoreceptors

Electron microscopic examination of the bases of adult rod and cone outer segments (rhesus monkey, ground squirrel, and grey squirrel) has led to a new model of disc morphogenesis. In this model the disc surfaces and disc rims develop by separate mechanisms and from separate regions of the membrane of the inner face of the cilium. This membrane is alternately specified into regions that will form either the disc surfaces or the disc rims. The disc surfaces develop by an evagination or outpouching of the ciliary membrane. The two surfaces of an evagination, scleral and vitreal, each form one of the surfaces of adjacent discs. The disc rim is initially specified as a region of ciliary membrane between adjacent disc-surface evaginations. This region grows bilaterally around the circumferences of adjacent discs, zippering together the apposed surfaces to form the rim and completed disc. At the same time it seals the plasma-membrane edges of the evaginations, which have become detached from the surfaces. Incisures form in rod discs by infolding of the rim and surfaces together, and they begin to form before the rim is completed around the disc perimeter. When a number of new discs are developing simultaneously the ciliary membrane at the base of an outer segment consists of a stack of rim forming and surface forming growth points. This model provides, in addition, for the continuous renewal of outer-segment plasma membrane. It also establishes a developmental basis for the structural uniqueness of the disc rim. Finally, it indicates an evolutionary relationship between the discs of vertebrate visual cells and the membrane specializations of invertebrate visual cells.
Onsager relations and hydrodynamic balance equations.

In this paper we clarify the role of heat flux in the hydrodynamic balance equations, facilitating the formulation of an Onsager relation within the framework of this theory. Previously thought to be unobtainable from the present form of the theory [X.L. Lei, J. Cai, and L.M. Xie, Phys. Rev. B 38, 1529 (1988)], our verification of the Onsager relation for linear particle and heat flux currents driven by electric fields and temperature gradients resolves a puzzling issue of long standing. Our results show that, for any temperature, when electron density is sufficiently high, the linear predictions of balance equation theory exactly satisfy the Onsager relation. The condition of high density is consonant with the requirement of strong electron-electron interactions for the validity of the Lei-Ting balance equations. Our results support the validity of this theory for a weakly nonuniform system. We also discuss a possible method of extending this theory to a system further removed from thermal equilibrium. \textcopyright{} 1996 The American Physical Society.
AGGREGATION ISSUES IN THE ESTIMATION OF LINEAR PROGRAMMING PRODUCTIVITY MEASURES

This paper demonstrates the sensitivity of the linear programming approach in the estimation of productivity measures in the primal framework. Specifically, the sensitivity to the number of constraints (level of dis-aggregation) and imposition of returns to scale constraints is evaluated. Further, the shadow or dual values are recovered from the linear program and compared to the market prices used in the ideal Fisher index approach. Empirical application to U.S. state-level time series data from 1960–2004 reveal productivity change decreases with increases in the number of constraints. Divergence in productivity measures is observed due to the choice of method imposed, various levels of commodity/input aggregation, and technology assumptions. Due to the piecewise linear approximation of the nonparametric programming approach, the shadow share-weights are skewed leading to the difference in the productivity measures due to aggregation.
Challenges on the frontier of intracoronary imaging: atherosclerotic plaque macrophage measurement by optical coherence tomography

Cellularity of the fibrous caps of coronary atheromas, manifested by the infiltration of macrophages (average size, 20 to 30 microm), is thought to weaken the structural integrity of the cap and predispose plaques to rupture. Therefore, an imaging technology capable of identifying macrophages within fibroatheroma caps in patients could provide valuable information for assessing plaque rupture risk. Recently, intravascular optical coherence tomography (OCT), a high-resolution coronary imaging modality, with an axial resolution of approximately 10 microm, has been introduced into the clinical setting. OCT images of the microstructure of the coronary artery wall enable accurate plaque-type characterization, supported by histopathological comparison data. Because of its high resolution, OCT may also be used to identify macrophages in vivo. In this paper we review recent developments in OCT for measuring macrophages in atherosclerotic plaques.
Computation of Time-Periodic Solutions of the Benjamin–Ono Equation

We present a spectrally accurate numerical method for finding nontrivial time-periodic solutions of nonlinear partial differential equations. The method is based on minimizing a functional (of the initial condition and the period) that is positive unless the solution is periodic, in which case it is zero. We solve an adjoint PDE to compute the gradient of this functional with respect to the initial condition. We include additional terms in the functional to specify the free parameters, which in the case of the Benjamin–Ono equation, are the mean, a spatial phase, a temporal phase, and the real part of one of the Fourier modes at t=0.
Kinetic model of ammonia synthesis in the solar nebula

Abstract The synthesis of ammonia in the primitive solar nebula was probably catalyzed by metallic iron grains because the gas phase reaction is kinetically inhibited. A preliminary kinetic model predicts a maximum of 3% of the nitrogen in the form of ammonia at the time of planetary accretion. Rates of reaction were derived from industrial data on ammonia iron catalysts. Due to the low rates of reaction, molecular nitrogen remains the dominant species even at the low temperatures where chemical equilibrium favors ammonia formation. Thus planetary atmospheres formed from a reservoir composed largely of molecular nitrogen. The non-equilibrium volatile gases (CO and N 2 ) suggested to comprise most of the carbon and nitrogen in comets is consistent with the model.
Incomplete mixing in a small, urban stream.

Abstract Conservative solute tracer experiments were conducted in Indian Creek, a small urban stream located in Philadelphia, Pennsylvania, USA. Estimated flow rates were between 46 L s −1 and 81 L s −1 , average stream width was 5.5 m and average stream depth was 0.2 m. Given these dimensions, most researchers would think it reasonable to assume that the stream is completely mixed vertically and horizontally. However, we found that the stream was not vertically completely mixed in a 1.0 m deep, 30 m long pool. The limited mixing was demonstrated by the vertical stratification of a tracer cloud which was completely mixed both laterally and vertically across the stream prior to entering the pool. We suggest that the cause of limited mixing is due to a balance between groundwater inflow and transverse dispersion at the cross-section. We show that the unsupported assumption of complete mixing may result in a wide range, and thus increased uncertainty, of the values of stream flow and longitudinal dispersion coefficient estimated from these data. We conclude that the assumption of complete mixing and one-dimensional modeling must be checked against actual field conditions, even in small streams.
Asymptomatic reactivation of herpes simplex virus in women after the first episode of genital herpes.

Abstract ▪Objective:To determine frequency, anatomic site, and host factors associated with asymptomatic shedding of herpes simplex virus after initial episodes of genital herpes. ▪Design:Cohort st...
A COMPARATIVE ASTROCHEMICAL STUDY OF THE HIGH-MASS PROTOSTELLAR OBJECTS NGC 7538 IRS 9 AND IRS 1

We report the results of a spectroscopic study of the high-mass protostellar object NGC 7538 IRS 9 and compare our observations to published data on the nearby object NGC 7538 IRS 1. Both objects originated in the same molecular cloud and appear to be at dierent points in their evolutionary histories, oering an unusual opportunity to study the temporal evolution of envelope chemistry in objects sharing a presumably identical starting composition. Observations were made with the Texas Echelon Cross Echelle Spectrograph (TEXES), a sensitive, high spectral resolution (R = = ’ 100,000) mid-infrared grating spectrometer. Forty-six individual lines in vibrational modes of the molecules C2H2, CH4, HCN, NH3 and CO were detected, including two isotopologues ( 13 CO, 12 C 18 O) and one combination mode ( 4 + 5 C2H2). Fitting synthetic spectra to the data yielded the Doppler shift, excitation temperature, Doppler b parameter, column density and covering factor for each molecule observed; we also computed column density upper limits for lines and species not detected, such as HNCO and OCS. We nd dierences among spectra of the two objects likely attributable to their diering radiation and thermal environments. Temperatures and column densities for the two objects are generally consistent, while the larger line widths toward IRS 9 result in less saturated lines than those toward IRS 1. Finally, we compute an upper limit on the size of the continuum-emitting region ( 2000 AU) and use this constraint and our spectroscopy results to construct a schematic model of IRS 9. Subject headings: stars: formation | stars: pre{main sequence | techniques: spectroscopic | ISM: individual objects (NGC 7538 IRS 9, NGC 7538 IRS 1)
Multisensor data fusion

Multisensor data fusion is a key enabling technology in which information from a number of sources is integrated to form a unified picture [1]. This concept has been applied to numerous fields and new applications are being explored constantly. Even though most multisensor data fusion applications have been developed relatively recently, the notion of data fusion has always been around. In fact, all of us employ multisensor data fusion principles in our daily lives. The human brain is an excellent example of an operational fusion system that performs extremely well. It integrates sensory information, namely sight, sound, smell, taste and touch data and makes inferences regarding the problem at hand. It has been a natural desire of researchers in different disciplines of science and engineering to emulate this information fusion ability of the human brain. The idea is that fusion of complementary information available from different sensors will yield more accurate results for information processing problems. Significant advances in this important field have been made but perfect emulation of the human brain remains an elusive goal.
Recognizing the first radiation sources through their 21 cm signature

At the beginning of the reionization epoch, radiation sources produce fluctuations in the redshifted 21 cm background. We show that different types of sources (such as miniquasars, Population II and III stars, supernovae, etc.) produce distinct signatures in the 21 cm signal radial profiles and statistical fluctuations, through which they can be identified. Furthermore, we show that the 21 cm signal from X-ray-emitting sources is much easier to observe than was expected, due to a previously neglected pumping mechanism.
Real-time block transfer under a link-sharing hierarchy

Most application data units are too large to be carried in a single packet (or cell) and must be segmented for network delivery. To an application, the end-to-end delays and loss rate of its data units are much more relevant performance measures than ones specified for individual packets (or cells). The concept of a burst (or block) was introduced to represent a sequence of packets (or cells) that carry an application data unit. We describe how a real-time variable bit-rate (VBR) service, with quality of service (QoS) parameters for block transfer delay and block loss rate, can be provided by integrating concepts and delay guarantee results from our previous work on burst scheduling, together with ideas from asynchronous transfer mode (ATM) block transfer. Two new contributions are presented herein. First, we design an admission control algorithm to provide the following two classes of service: bounded-delay block transfer with no loss, and bounded-delay block transfer at a specified block loss rate. Secondly, we show how to extend existing end-to-end delay bounds to networks with hierarchical link sharing.
Turtle: Identifying frequent k -mers with cache-efficient algorithms

Motivation: Counting the frequencies of k-mers in read libraries is often a first step in the analysis of high-throughput sequencing data. Infrequent k-mers are assumed to be a result of sequencing errors. The frequent k-mers constitute a reduced but error-free representation of the experiment, which can inform read error correction or serve as the input to de novo assembly methods. Ideally, the memory requirement for counting should be linear in the number of frequent k-mers and not in the, typically much larger, total number of k-mers in the read library. Results: We present a novel method that balances time, space and accuracy requirements to efficiently extract frequent k-mers even for high-coverage libraries and large genomes such as human. Our method is designed to minimize cache misses in a cache-efficient manner by using a pattern-blocked Bloom filter to remove infrequent k-mers from consideration in combination with a novel sort-and-compact scheme, instead of a hash, for the actual counting. Although this increases theoretical complexity, the savings in cache misses reduce the empirical running times. A variant of method can resort to a counting Bloom filter for even larger savings in memory at the expense of false-negative rates in addition to the false-positive rates common to all Bloom filter-based approaches. A comparison with the state-ofthe-art shows reduced memory requirements and running times. Availability and implementation: The tools are freely available for download at http://bioinformatics.rutgers.edu/Software/Turtle and http://figshare.com/articles/Turtle/791582.
EVALUATING DISCOURSE PROCESSING ALGORITHMS

In order to take steps towards establishing a methodology for evaluating Natural Language systems, we conducted a case study. We attempt to evaluate two different approaches to anaphoric processing in discourse by comparing the accuracy and coverage of two published algorithms for finding the co-specifiers of pronouns in naturally occurring texts and dialogues. We present the quantitative results of hand-simulating these algorithms, but this analysis naturally gives rise to both a qualititive evaluation and recommendations for performing such evaluations in general. We illustrate the general difficulties encountered with quantitative evaluation. These are problems with: (a) allowing for underlying assumptions, (b) determining how to handle underspecifications, and (c) evaluating the contribution of false positives and error chaining.
THE DISTRIBUTIONAL BEHAVIOR OF FUTURES PRICE SPREADS

The distributional behavior of futures price spreads is examined for four commodities: corn, live cattle, gold and T-bonds. Remarkably different results are found over commodities, time period, and sample size. Actual spread changes for the smaller sample size of gold and T-bonds and for corn produce more normal distributions for weekly than for daily differencing intervals, while all live cattle spreads for actual changes are normally distributed. However, the larger sample size of both gold and T-bonds and the relative spread changes for corn and live cattle do not become more normally distributed under temporal aggregation of the data.
Correlated Phases of Bosons in Tilted Frustrated Lattices

We study the ``tilting'' of Mott insulators of bosons into metastable states. These are described by Hamiltonians acting on resonant subspaces and have rich possibilities for correlated phases with nontrivial entanglement of pseudospin degrees of freedom encoded in the boson density. We extend a previous study [S. Sachdev, K. Sengupta, and S. M. Girvin, Phys. Rev. B 66, 075128 (2002)] of cubic lattices to a variety of lattices and tilt directions in two dimensions: square, decorated square, triangular, and kagome. For certain configurations three-body interactions are necessary to ensure that the energy of the effective resonant subspace is bounded from below. We find quantum phases with Ising density wave order and with superfluidity transverse to the tilt direction, and a quantum liquid state with no broken symmetry. The existence of the quantum liquid state is shown by an exact solution for a particular correlated boson model. We also find cases for which the resonant subspace is described by effective quantum dimer models.
Longitudinal and Transverse Space Charge Limitations on Transport of Maximum Power Beams

The maximum transportable beam power is a critical issue in selecting the most favorable approach to generating ignition pulses for inertial fusion with high energy accelerators. Maschke and Courant1 have put forward expressions for the limits on transport power for quadrupole and solenoidal channels. We have included in a more general way the self consistent effect of space charge defocusing on the power limit. The results show that no limits on transmitted power exist in principal. In general, quadrupole transport magnets appear superior to solenoids except for transport of very low energy and highly charged particles. Longitudinal space charge effects are very significant for transport of intense beams.
Sources and Mechanisms of Carbon Monoxide Production by Irradiation

The sources and mechanisres of gas production by irradiation were determined using model systems prepared with fatty acid, phospholipids, oil, surgars, glycolysis and TCA cycle intermediates, nucleic acids, amino acid monomers and homopolymers, and proteins. The model systems were icradiated at 0, 2.5, 5, or 10 kGy using a linear accelerator and the amounts of CO, CO 3 , and CH 4 produced were determined using gas chromatography. The productions of CO, CO 2 , and CH 4 In all samples were irradiation-dose dependent. Glycine, asparagine, and glutarnine were the major sources of CO production among amino acids, and glyceraidehydes, pyruvate, and α-ketoglutarate were the major sources of CO among glycolysis intermediates. Phosphatidyl cholirte, phosphatidyl ethanolamine, and lysophosphatidyl choline produced the greatest amounts of CO among the phospholipids. The major sources of CO 2 production were pyravate, threoine, and methlonine, and those of CH 4 were methlorine and acetone. The amounts of CO produced from these sources were significant, and the production of gas compounds via radiolytic degradation appears to be closely related to the structure of molecules.
Complexity constrained rate-distortion optimization of sign language video using an objective intelligibility metric

Sign language users are eager for the freedom and convenience of video communication over cellular devices. Compression of sign language video in this setting offers unique challenges. The low bitrates available make encoding decisions extremely important, while the power constraints of the device limit the encoder complexity. The ultimate goal is to maximize the intelligibility of the conversation given the rate-constrained cellular channel and power constrained encoding device. This paper uses an objective measure of intelligibility, based on subjective testing with members of the Deaf community, for rate-distortion optimization of sign language video within the H.264 framework. Performance bounds are established by using the intelligibility metric in a Lagrangian cost function along with a trellis search to make optimal mode and quantizer decisions for each macroblock. The optimal QP values are analyzed and the unique structure of sign language is exploited in order to reduce complexity by three orders of magnitude relative to the trellis search technique with no loss in rate-distortion performance. Further reductions in complexity are made by eliminating rarely occuring modes in the encoding process. The low complexity SL optimization technique increases the measured intelligibility up to 3.5 dB, at fixed rates, and reduces rate by as much as 60% at fixed levels of intelligibility with respect to a rate control algorithm designed for aesthetic distortion as measured by MSE.
Fourier Transforms of Positive Definite Kernels and the Riemann \(\xi \)-Function

The purpose of this paper is to investigate the distribution of zeros of entire functions which can be represented as the Fourier transforms of certain admissible kernels. The principal results bring to light the intimate connection between the Bochner–Khinchin–Mathias theory of positive definite kernels and the generalized real Laguerre inequalities. The concavity and convexity properties of the Jacobi theta function play a prominent role throughout this work. The paper concludes with several questions and open problems.
The business case for pediatric asthma quality improvement in low-income populations: examining a provider-based pay-for-reporting intervention.

Objective: To measure the return on investment (ROI) for a pediatric asthma pay-for-reporting intervention initiated by a Medicaid managed care plan in New York State. Design: Practice-level, randomized prospective evaluation. Setting: Twenty-five primary care practices providing care to children enrolled in the Monroe Plan for Medical Care (the Monroe Plan). Participants: Practices were randomized to either treatment (13 practices, 11 participated) or control (12 practices). Intervention: For each of its eligible members assigned to a treatment group practice, the Monroe plan paid a low monthly incentive fee to the practice. To receive the incentive, treatment group practices were required to conduct, and report to the Monroe Plan, the results of chart audits on eligible members. Chart audits were conducted by practices every 6 months. Aftereach chart audit, the Monroe Plan provided performance feedback to each practice comparing its adherence to asthma care guidelines with averages from all other treatment group practices. Control practices continued with usual care. Main Outcome Measures: Intervention implementation and operating costs and per member, per month claims costs. ROI was measured by net present value (discounted cash flow analysis). Results: The ROI to the Monroe Plan was negative, primarily due to high intervention costs and lack of reductions in spending on emergency department and hospital utilization forchildren in treatment relative to control practices. Conclusions: A pay-for-reporting, chart audit intervention is unlikely to achieve the meaningful reductions in utilization of high-cost services that would be necessary to produce a financial ROI in 2.5 years.
Combustion properties of biomass

Properties of biomass relevant to combustion are briefly reviewed. The compositions of biomass among fuel types are variable, especially with respect to inorganic constituents important to the critical problems of fouling and slagging. Alkali and alkaline earth metals, in combination with other fuel elements such as silica and sulfur, and facilitated by the presence of chlorine, are responsible for many undesirable reactions in combustion furnaces and power boilers. Reductions in the concentrations of alkali metals and chlorine, created by leaching the elements from the fuel with water, yield remarkable improvements in ash fusion temperatures and confirm much of what is suggested regarding the nature of fouling by biomass fuels. Other influences of biomass composition are observed for the rates of combustion and pollutant emissions. Standardized engineering practices setting out protocols of analysis and interpretation may prove useful in reducing unfavorable impacts and industry costs, and further development is encouraged.