cssi/SciSciGPT-SciSciNet huggingface dataset:
Vadose Zone Characterization and Monitoring Beneath Waste Disposal Pits Using Horizontal Boreholes

Vadose zone characterization and monitoring immediately below landfills using horizontal boreholes is an emerging technology. However, this topic has received little attention in the peer-reviewed literature. The value of this approach is that activities are conducted below the waste, providing clear and rapid verification of containment. Here we report on two studies that examined the utility of horizontal boreholes for environmental characterization and monitoring under radioactive waste disposal pits. Both studies used core sample analyses to determine the presence of various radionuclides, organic compounds, or metals. At one borehole site, water content and pore-water chloride concentrations were also used to interpret vadose zone behavior. At another site, we examined the feasibility of using flexible membrane liners in uncased boreholes for periodic monitoring. For this demonstration, these retrievable liners were air-injected into boreholes on multiple occasions carrying different instrument packages for environmental surveillance. These included a neutron logging device to measure volumetric water at regular intervals, high-absorbency collectors that wicked available water from borehole walls, or vent tubes that were used to measure air permeability and collect air samples. The flexible and retrievable liner system was an effective way to monitor water content and measure in situ air permeability. The high-absorbency collectors were efficient at extracting liquid water for contaminant analyses even at volumetric water contents below 10%, and revealed tritium migration below one disposal pit. Both demonstration studies proved that effective characterization and periodic monitoring in horizontal boreholes is both feasible and adaptable to many waste disposal problems and locations.
Sequence Specification for Concurrent Object-Oriented Applications

Modeling synchronization among threads is important for the specification, design, and testing of concurrent object-oriented applications such as those written in Java. This paper proposes Synchron...
WE-A-BRA-03: Towards real-time ultrasound image-guided abdominal radiotherapy

Accurate tumor positioning in stereotactic body radiotherapy of abdominal lesions is often hampered by organ motion and set-up errors. The problems of the daily variation (interfractional motion) in tumor position can be partially corrected with on-line soft-tissue image-guided radiotherapy. However, a greater challenge is to also capture the movement during treatment (intrafractional motion).
Housing policy in the wake of the crash

In this article the author examines aspects of U.S. housing policy in the aftermath of the global financial crisis of 2008-09. The author notes that between the years 2000 and 2010 the U.S. housing market underwent extremes of prosperity and financial failure as home prices rose precipitously, and then fell following the financial crisis. A number of topics are addressed including fluctuations in the construction industry, the sharp increase in home prices in Las Vegas, Nevada, and Phoenix, Arizona, and the tax deduction for mortgage interest on homes.
Nonpropulsive applications of ion beams

Eight centimeter ion beam sources utilizing xenon and argon have been developed that operate over a wide range of beam energies and currents. Three types of processes have been studied: sputter deposition, ion beam machining, and ion beam surface texturing. The broad range of source operating conditions allows optimum sputter deposition of various materials. An ion beam source was used to ion mill laser reflection holograms using photoresist patterns on silicon. Ion beam texturing was tried with many materials and has a multitude of potential applications.
Emerging Foodborne Diseases: An Evolving Public Health Challenge

The epidemiology of foodborne disease is changing. New pathogens have emerged, and some have spread worldwide. Many, including Salmonella, Escherichia coli O157:H7, Campylobacter, and Yersinia enterocolitica, have reservoirs in healthy food animals, from which they spread to an increasing variety of foods. These pathogens cause millions of cases of sporadic illness and chronic complications, as well as large and challenging outbreaks over many states and nations. Improved surveillance that combines rapid subtyping methods, cluster identification, and collaborative epidemiologic investigation can identify and halt large, dispersed outbreaks. Outbreak investigations and case-control studies of sporadic cases can identify sources of infection and guide the development of specific prevention strategies. Better understanding of how pathogens persist in animal reservoirs is also critical to successful long-term prevention. In the past, the central challenge of foodborne disease lay in preventing the contamination of human food with sewage or animal manure. In the future, prevention of foodborne disease will increasingly depend on controlling contamination of feed and water consumed by the animals themselves.
On the Geodesic Hypothesis in General Relativity

In this paper, we give a rigorous derivation of Einstein’s geodesic hypothesis in general relativity. We use small material bodies \({\phi^\epsilon}\) governed by the nonlinear Klein–Gordon equations to approximate the test particle. Given a vacuum spacetime \({([0, T]\times\mathbb{R}^3, h)}\) , we consider the initial value problem for the Einstein-scalar field system. For all sufficiently small e and δ ≤ eq, q > 1, where δ, e are the amplitude and size of the particle, we show the existence of the solution \({([0, T]\times\mathbb{R}^3, g, \phi^\epsilon)}\) to the Einstein-scalar field system with the property that the energy of the particle \({\phi^\epsilon}\) is concentrated along a timelike geodesic. Moreover, the gravitational field produced by \({\phi^\epsilon}\) is negligibly small in C1, that is, the spacetime metric g is C1 close to the given vacuum metric h. These results generalize those obtained by Stuart in (Ann Sci Ecole Norm Sup (4) 37(2):312–362, 2004, J Math Pures Appl (9) 83(5):541–587, 2004).
Fault-tolerant routing in peer-to-peer systems

We consider the problem of designing an overlay network and routing mechanism that permits finding resources efficiently in a peer-to-peer system. We argue that many existing approaches to this problem can be modeled as the construction of a random graph embedded in a metric space whose points represent resource identifiers, where the probability of a connection between two nodes depends only on the distance between them in the metric space. We study the performance of a peer-to-peer system where nodes are embedded at grid points in a simple metric space: a one-dimensional real line. We prove upper and lower bounds on the message complexity of locating particular resources in such a system, under a variety of assumptions about failures of either nodes or the connections between them. Our lower bounds in particular show that the use of inverse power-law distributions in routing, as suggested by Kleinberg [5], is close to optimal. We also give heuristics to efficiently maintain a network supporting efficient routing as nodes enter and leave the system. Finally, we give some experimental results that suggest promising directions for future work.
Topology and chiral symmetry in finite temperature QCD

Abstract We investigate the realization of chiral symmetry in the vicinity of the deconfinement transition in quenched QCD using overlap fermions. Via the index theorem obeyed by the overlap fermions, we gain insight into the behavior of topology at finite temperature. We find small eigenvalues, clearly separated from the bulk of the eigenvalues, and study the properties of their distribution. We compare the distribution with a model of a dilute gas of instantons and anti-instantons and find good agreement.
Instantons on D-branes

We consider type IIA compactification on K3. We show that the instanton subsectors of the worldvolume of N 4-branes wrapped around K3 lead to a Hagedom density of BPS states in accord with heterotic-type IIA duality in 6 dimensions. We also find evidence that the correct framework to understand the results of Nakajima on the appearance of affine Kac-Moody algebras on the cohomology of moduli space of instantons on ALE spaces is in the context of heterotic-type IIA string duality.
3D milk-fouling model of plate heat exchangers using computational fluid dynamics

A 3D fouling model for milk pasteurization using PHEs (plate heat exchangers) was developed using CFD (computational fluid dynamics). Based on the hydrodynamic and thermodynamic performances of PHEs in a 3D environment, the chemical reaction equations employed for protein denaturation and absorption onto the stainless steel surface were coupled using the fluent software. The 10-channel PHE system with both counter-current and cocurrent flows was applied to validate the model by visualizing and quantifying the milk deposit formulated in the fluid channels. The predicted mass deposit values were in good agreement with the experimental data with the prediction error of 0.01 g or 1%. The simulation results based on new PHE system, designed for the uniformity of flow distribution, showed the deposited mass could be reduced to 1/10, compared to the current system under identical energy condition. Although the computational efforts required were quite intensive, the 3D fouling model was validated as an effective tool for design of new plate shape and corrugation profile optimized for minimizing milk fouling.
Hitting Reply: A Qualitative Study to Understand Student Decisions to Respond to Online Discussion Postings.

Providing tools for dialogue exchange does not ensure that students will respond to team mate postings or that online groups will grow in cohesiveness. Students decide whether or not to reply, and it is increasingly important to understand how students make these decisions due to the increase in distance education, millenials, and asynchronous teamwork in the workplace. This exploratory qualitative study was based on an interpretivist philosophy to understand how students reply to discussion postings. Students from two Master's-level research classes were asked why they chose to respond to certain discussion postings and why they chose not to reply to certain postings. The reasons why students responded to postings were clustered into four themes: group process criteria, leadership criteria, social criteria, and judgment criteria. The reasons why students did not respond fell into the criteria of applicability, judgment, leadership, and social criteria. Implications for e-learning instructors and practitioners are discussed in terms of promoting social presence and facilitating collaborative group work. Both the popular and scholarly press focusing on online teaching contain research-based strategies for facilitating online asynchronous communication. Researchers have proposed ways to make learning spaces conducive to discussion and practitioners have developed strategies for evoking student participation online. The literature includes the study of participation rates and patterns (Hara et al, 2000), the application of social, cognitive, and teaching presence research to assess online discussion (Pelz, 2004), and learning strategies that facilitate learning in asynchronous discussions (Kanuka & Garrison, 2004). However, little is known about the decision processes used by students when they decide to respond to asynchronous communication (Virk, 2004). In a face- to-face course, students can use a variety of criteria to decide whether to interact with one another. In the online classroom, students are forced to base their decisions on whether to interact without those cues. In the face-to-face environment, expression is much more detailed (Becker-Beck et al, 2005). In order to understand more about this difference, the foundationalist epistemology was rejected in favor of the interpretivist philosophy of empathic identification. This choice precludes an exact, final, or decisive interpretation of the qualitative data collected in this study. Instead, the interpretations generated from the data analysis represent an insider's view of the intentionality of online students to 'hit reply'. This research contributes to our understandings of how online learners decide to interact in online discussions. The findings may help online educators to understand more about the meanings students ascribe to 'hitting reply', and improve the quality and depth of their online student discussions.
Spatial Convergence and Spillovers in American Invention

Abstract Endogenous growth theory places spatial knowledge spillovers at the center of national technological progress. Advances in spatial autocorrelation and regression analyses provide methods to assess the influence of these spillovers on the geographical distribution and growth of invention. This article investigates interstate inequality and convergence in per capita patenting in the United States in the period 1963–2003. We analyze both the complete forty years and trends in ten-year intervals. Moran's I reveals spatial dependence in patenting levels and growth, and LISA cluster maps identify regional groupings of leading and trailing states. Our regression results show that both regional effects and spatial spillovers influence convergence rates, which were low and steady in the thirty years before 1993. In the subsequent decade, patenting expansion concentrated in a few states, inequality increased, and divergence ensued. Western states, in general, and the Pacific Northwest, in particular, incre...
The Photometric Method of Extrasolar Planet Detection Revisited

We investigate the geometry concerning the photometric method of extrasolar planet detection, i.e., the detection of dimiuntion of a parent star’s brightness during a planetary transit. Under the assumption that planetary orbital inclinations can be defined by a Gaussian with a σ of 10° centered on the parent star’s equatorial plane, Monte Carlo simulations suggest that for a given star observed at an inclination of exactly 90°, the probability of at least one Earth-sized or larger planet being suitably placed for transits is approximately 4%. This probability drops to 3% for a star observed at an inclination of 80°, and is still ∼ 0.5% for a star observed at an inclination of 60°. If one can select 100 stars with a pre-determined inclination ≥ 80°, the probability of at least one planet being suitably configured for transits is 95%. The majority of transit events are due to planets in small-a orbits similar to the Earth and Venus; thus, the photometric method in principle is the method best suited for the detection of Earthlike planets.
A prosodic phrasing model for a Korean text-to-speech synthesis system

This paper presents a prosodic phrasing model for Korean to be used in a text-to-speech synthesis (TTS) system. Read text corpora were morpho-syntactically parsed and prosodically labeled following the Penn Korean Treebank (Han, Chunghye, Ko, Eon-Suk, Yi, Heejong, Palmer, M., 2002. Penn Korean Treebank: development and evaluation. In: Proceedings of the 16th Pacific Asian Conference on Language and Computation. Korean Society for Language and Information.) and K-ToBI prosodic labeling conventions (Sun-Ah, J., 2000. K-ToBI (Korean ToBI) labelling conventions. Version 3.1. Available from: URL .), respectively. Decision trees were trained with morpho-syntactic and textual distance features to predict locations of accentual and intonational phrase breaks. Our phrasing model cross-validated on a 300-sentence corpus (6936 words or 21,436 syllables, with an average of 72 syllables or 23 words per sentence) predicted non-breaks with F=92.4% and breaks with F=88.0% (F=72.8% for accentual phrase breaks and F=71.3% for intonational phrase breaks).
Miocene Structural Features Of North And South Padre Island And Ocs Areas, Offshore South Texas

Integration of 2-D seismic reflection data, paleontological reports, velocity analysis, and well logs has provided a new structural model for North and South Padre Island OCS areas. The Clemente-Tomas fault system (Late Oligocene-Early Miocene) is located above overpressured shale ridges. Sediment loading initiated the faulting over the compacted shale. The Corsair fault system (Early-Middle Miocene) is located seaward of Clemente-Tomas and was formed due to a huge sediment influx that forced the salt to withdraw basinward. The Wanda fault system formed during the Late Miocene because of the further salt withdrawal. Study area is dominated by shale ridges and the salt are only formed beneath the present shelf edge as salt diapirs. Overpressured shale was mapped throughout the study area. Well logs show overpressured shale between 8,800 to 12,000 feet. Berg and Avery suggested that growth faults can seal the faults sheared zones which may cause a structural hydrocarbon trap. We examined most of the responses of the dip logs in the study area and we found that the seal general trend is the drag (non seal) type.
Self-Dual Nonsupersymmetric Type II String Compactifications

It has recently been proposed that certain nonsupersymmetric type II orbifolds have vanishing perturbative contributions to the cosmological constant. We show that techniques of Sen and Vafa allow one to construct dual type II descriptions of these models (some of which have no weakly coupled heterotic dual). The dual type II models are given by the same orbifolds with the string coupling S and a T{sup 2} volume T exchanged. This allows us to argue that in various strongly coupled limits of the original type II models, there are weakly coupled duals which exhibit the same perturbative cancellations as the original models.
Review of theory of distortion and disintegration of liquid streams

Abstract Linear and nonlinear analyses of the instabilities and distortion of liquid streams injected into a gaseous media are discussed. The various fundamental mechanisms and the predictive capabilities for the distortions are emphasized. Round jets, planar sheets, annular sheets, and conical sheets are discussed in detail. The balance between capillary and inertial forces is primarily examined. The method for simplifying the analyses in the case of thin liquid sheets is discussed. The capabilities for representing the droplet size distribution that follows the stream disintegration are outlined.
The Tumultuous Lives of Galactic Dwarfs and the Missing Satellites Problem

Hierarchical cold dark matter (CDM) models predict that Milky Way-sized halos contain several hundred dense low-mass dark matter satellites (the substructure), an order of magnitude more than the number of observed satellites in the Local Group. If the CDM paradigm is correct, this prediction implies that the Milky Way and Andromeda are filled with numerous dark halos. To understand why these halos failed to form stars and become galaxies, we need to understand their history. We analyze the dynamical evolution of the substructure halos in a high-resolution cosmological simulation of Milky Way-sized halos in the ?CDM cosmology. We find that about 10% of the substructure halos with the present masses 108-109 M? (circular velocities Vm 30 km s-1) had considerably larger masses and circular velocities when they formed at redshifts z 2. After the initial period of mass accretion in isolation, these objects experience dramatic mass loss because of tidal stripping. Our analysis shows that strong tidal interaction is often caused by actively merging massive neighboring halos, even before the satellites are accreted by their host halo. These results can explain how the smallest dwarf spheroidal galaxies of the Local Group were able to build up a sizable stellar mass in their seemingly shallow potential wells. We propose a new model in which all the luminous dwarf spheroidals in the Local Group are descendants of the relatively massive (109 M?) high-redshift systems, in which the gas could cool efficiently by atomic line emission, and which were not significantly affected by the extragalactic ultraviolet radiation. We present a simple galaxy formation model based on the trajectories extracted from the simulation, which accounts for the bursts of star formation after strong tidal shocks and the inefficiency of gas cooling in halos with virial temperatures Tvir 104 K. Our model reproduces the abundance, spatial distribution, and morphological segregation of the observed Galactic satellites. The results are insensitive to the redshift of reionization.
A control-theoretic perspective on the design of distributed agreement protocols

We present a control-theoretic perspective on the design of distributed agreement protocols. First, we explore agreement-protocol analysis and design for a network of agents with single-integrator dynamics and arbitrary linear observations. One key contribution of our work is the analysis of protocols for networks with quite general observation topologies, including with multiple observations made by each agent. Another contribution is the development of techniques for agreement law design—i.e. for assignment of the dependence of the agreed-upon value on the initial states of the agents. Second, we explore agreement in a quasi-linear model with a stochastic protocol, which we call the controlled voter model. We motivate our study of this model, develop tests for whether agreement is achieved, and consider design of the agreement law. Third, we expose one application of agreement law design, to distributed maximum a posteriori probability (MAP) decision making and hidden Markov model (HMM) estimation. Finally, we provide some further thoughts regarding our control-theoretic perspective on agreement, including ideas for fault-tolerant protocol design using our approach. Copyright © 2006 John Wiley & Sons, Ltd.
A Common-Source Outbreak of Staphylococcus epidermidis Infections among Patients Undergoing Cardiac Surgery

A single strain of Staphylococcus epidermidis caused an outbreak of postoperative wound infections and endocarditis during a 6-month period. Infections caused by the epidemic strain developed more frequently in valve surgery patients than in those undergoing coronary artery bypass graft surgery (P = .03) and occurred only in patients operated on by surgeon A. None of 17 members of the cardiac surgery team carried the epidemic strain in their anterior nares, axillae, or inguinal folds. Hand cultures were performed on 8 surgical personnel, and only surgeon A carried the epidemic strain on his hands. Isolates from cardiac surgery patients, bypass pump blood cultures, and the hands of the implicated surgeon all had identical antimicrobial susceptibility patterns, plasmid profiles, and EcoRI restriction endonuclease digest patterns. In the 24 months after control measures were implemented, no infections caused by the epidemic strain occurred among open heart surgery patients. The findings suggest that the common-source outbreak of infections among cardiac surgery patients was due to carriage of a strain S. epidermidis on the hands of a cardiac surgeon.
Spatial Degrees of Freedom in Everett Quantum Mechanics

Stapp claims that, when spatial degrees of freedom are taken into account, Everett quantum mechanics is ambiguous due to a “core basis problem.” To examine an aspect of this claim I generalize the ideal measurement model to include translational degrees of freedom for both the measured system and the measuring apparatus. Analysis of this generalized model using the Everett interpretation in the Heisenberg picture shows that it makes unambiguous predictions for the possible results of measurements and their respective probabilities. The presence of translational degrees of freedom for the measuring apparatus affects the probabilities of measurement outcomes in the same way that a mixed state for the measured system would. Examination of a measurement scenario involving several observers illustrates the consistency of the model with perceived spatial localization of the measuring apparatus.
Shots for Tots

By endorsing the use of a vaccine that makes the experience of puffing on a cigarette deeply distasteful, Lieber and Millum have taken the first few tentative steps into a future filled with medical interventions that manipulate individual preferences. It is tempting to embrace the careful arguments of “Preventing Sin” and celebrate the possibility that the profound individual and social costs of smoking will finally be tamed. Yet there is something unsettling about the possibility that parental discretion may be on the cusp of a radical expansion, one that involves a new and unexplored approach to behavior modification.
Astrophysical and Astrobiological Implications of Gamma-Ray Burst Properties

Combining results from Schmidt for the local cosmic rate and mean peak luminosity of γ-ray bursts (GRBs) with results on the history of the cosmic star formation rate (SFR), we provide estimates for the local GRB rate per unit blue luminosity in galaxies. For a moderate increase in SFR with redshift, we find a GRB rate per unit B luminosity of 2.4 × 10-17 hLyr-1. The corresponding mean γ-ray luminosity density in the Milky Way is 1.6 × 1029 ergs s-1 pc-2, and the total rate is 5.5 × 10-7 h yr-1. These values are used to examine a number of phenomena with the following conclusions: (1) The ratio of supernova rate to isotropic equivalent GRB rate is large: 6000 SNe Ibc per GRB, 30,000 SNe II per GRB. With no correction for collimation, it is difficult to maintain that more than a small fraction of neutron star- or black hole-forming events produce GRBs. GRBs could arise in a large fraction of black hole- or magnetar-forming events only with collimation in the range ΔΩ/4π ~ 0.01-0.001 and a steep enough slope of the initial mass function. (2) Without substantial collimation, the GRB rate is small; with collimation, the energy input is small. The net effect is that it is impossible to use these events to account for the majority of large H I holes observed in our own and other galaxies. (3) Modeling the GRB events in the Milky Way as a spatial Poisson process and allowing for modest enhancement in the star formation rate due to birth in a spiral arm, we find that the probability that the solar system was exposed to a fluence large enough to melt the chondrules during the first 107 yr of solar system history is negligibly small, independent of collimation effects. This is especially true considering that there is strong evidence that the chondrules were melted more than once. (4) We calculate the probability that surfaces of planets and satellites have been subjected to irradiation from GRBs at fluence levels exceeding those required for DNA alterations during a given period of time. Downscattering to energies at which photoelectric absorption occurs results in a transmission factor for ionizing radiation that is an exponential function of the atmospheric column density. Even for very opaque atmospheres, a significant fraction of the GRB energy is transmitted as UV lines because of excitation by secondary electrons. For eukaryotic-like organisms in thin atmospheres (e.g., contemporary Mars) or for UV line exposure in thick atmospheres (e.g., Earth), biologically significant events occur at a rate of ~100-500 Gyr-1. The direct contribution of these "jolts" to mutational evolution may, however, be negligible because of the short duration of the GRBs. Evolutionary effects due to partial sterilizations and to longer lived disruptions of atmospheric chemistry should be more important.
Consistent asymptotic expansion of Mott's solution for oxide growth

Abstract Many relatively thick metal oxide films grow according to what is called the parabolic law L = 2 A t + … . Mott explained this for monovalent carriers by assuming that monovalent ions and electrons are the bulk charge carriers, and that their number fluxes vary as t − 1/2 at sufficiently long t . In this theory no bulk charge was present, and surface charges were not discussed. However, it can be analyzed in terms of a discharging capacitor, with the oxide surfaces as the plates. The theory is inconsistent because the field decreases, corresponding to discharge, but there is no net current to cause discharge. The present work, which also includes multi-valent carriers, systematically extends the theory and obtains the discharge current. Because the Planck–Nernst equations are nonlinear (although Gauss's Law and the continuity equations are linear) this leads to a systematic order-by-order expansion in powers of t − 1/2 for the number currents, concentrations, and electric field during oxide growth. At higher order the bulk develops a non-zero charge density, with a corresponding non-uniform net current, and there are corrections to the electric field and the charge-carrier currents. The second order correction to the ion current implies a logarithmic term in the thickness of the oxide layer: L = 2 A t + B ln t + … . It would be of interest to verify this result with high-precision measurements.
Diel feeding behavior and ingestion rate in the copepod Calanus finmarchicus in the southern Gulf of Maine during late spring

Abstract In situ feeding was measured on late stage Calanus finmarchicus in the southern Gulf of Maine during late spring 1988 and 1989. The region is a spring feeding ground for the planktivorous right whale, Eubalaena glacialis . Measurements in 1988 were made during the declining spring bloom, when phytoplankton showed considerable spatial variability. 1989 observations were made after summer stratification had become established, when phytoplankton biomass was low and dominated by the In situ ingestion rates of C. finmarchicus reflected these differences in food, and ranged from 30.2% body C day −1 at a spring bloom station to 0.6% body C day −1 after stratification. These values compare with a maximum ingestion rate of 44.3% body C day −1 measured in a shipboard grazing experiment using cultured algae as food, and indicate that C. finmarchicus became food limited in the southern Gulf of Maine after stratification. Calanus finmarchicus diet feeding behavior and diet vertical migration patterns changed during the seasonal progression from spring bloom to summer stratification. Diet feeding rhythms and vertical migration were absent during the bloom, but developed as the bloom declined. During the post-bloom stratified conditions, diet feeding rhythms continued but vertical migration ceased. Most of the C. finmarchicus population remained near the surface, while a small population of nonmigratory individuals resided at depth and appeared to be feeding upon sedimented spring bloom diatoms. At the spring bloom station C. finmarchicus ingested only a small proportion of the phytoplankton standing stock in the > 7 μm size fraction (2.9% day −1 ), reflecting the high biomass of phytoplankton and the stage composition of the C. finmarchicus population, dominated by early copepodite stages with low biomass. In contrast, at the post-bloom stations in 1989, the dense surface aggregations of C. finmarchicus populations were dominated by late copepodite stages whose total biomass was comparable to that of the phytoplankton, and C. finmarchicus consumed a significantly larger fraction of the > 7 μm phytoplankton standing crop (up to 62.5% day −1 .
Object-oriented concurrent programming in CST

CST is a programming language based on Smalltalk-80 that supports concurrency using locks, asynchronous messages, and distributed objects. Distributed objects have their state distributed across many nodes of a machine, but are referred to by a single name. Distributed objects are capable of processing many messages simultaneously and can be used to efficiently connect together large collections of objects. They can be used to construct a number of useful abstractions for concurrency. This paper describes the CST language, gives examples of its use, and discusses an initial implementation.
Seeding influential nodes in non-submodular models of information diffusion

We consider the model of information diffusion in social networks from [2] which incorporates trust (weighted links) between actors, and allows actors to actively participate in the spreading process, specifically through the ability to query friends for additional information. This model captures how social agents transmit and act upon information more realistically as compared to the simpler threshold and cascade models. However, it is more difficult to analyze, in particular with respect to seeding strategies. We present efficient, scalable algorithms for determining good seed sets -- initial nodes to inject with the information. Our general approach is to reduce our model to a class of simpler models for which provably good sets can be constructed. By tuning this class of simpler models, we obtain a good seed set for the original more complex model. We call this the projected greedy approach because you `project' your model onto a class of simpler models where a greedy seed set selection is near-optimal. We demonstrate the effectiveness of our seeding strategy on synthetic graphs as well as a realistic San Diego evacuation network constructed during the 2007 fires.
Belief semantics of authorization logic

A formal belief semantics for authorization logics is given. The belief semantics is proved to subsume a standard Kripke semantics. The belief semantics yields a direct representation of principals' beliefs, without resorting to the technical machinery used in Kripke semantics. A proof system is given for the logic; that system is proved sound with respect to the belief and Kripke semantics. The soundness proofs are mechanized in Coq.
Collective properties of excitons in the presence of a two-dimensional electron gas

Abstract We have studied the collective properties of two-dimensional (2D) excitons immersed within a quantum well which contains 2D excitons and a two-dimensional electron gas (2DEG). We have also analyzed the excitations for a system of 2D dipole excitons with spatially separated electrons and holes in a pair of quantum wells (CQWs) when one of the wells contains a 2DEG. Calculations of the superfluid density and the Kosterlitz–Thouless (K–T) phase transition temperature for the 2DEG-exciton system in a quantum well have shown that the K–T transition temperature increase with increasing exciton density and that it might be possible to have fast long-range transport of excitons. The superfluid density and the K–T transition temperature for dipole excitons in CQWs in the presence of a 2DEG in one of the wells increases with increasing inter-well separation.
A convenient procedure for the synthesis of enyne-allenes

Abstract Bromoboration of 1-hexyne with BBr 3 followed by treatment with 2-propanol produced alkenyl boronic ester 3 . Subsequent Pd(0)-catalyzed cross-coupling with acetylenic zinc chlorides and iodination furnished enyne iodides 6 , which were then converted to enyne-allenes 8 by a second Pd(0)-catalyzed reaction with allenic zinc chlorides.
The Globular Cluster Luminosity Function as a Distance Indicator: Dynamical Effects

The dynamical evolution of the globular cluster systems in external galaxies is estimated, based on the standard dynamical theory normalized to the Milky Way. Assuming the same initial luminosity function, we construct an intrinsic distribution of globular clusters resulting from an isolated, passive evolution over the Hubble time of the true initial distribution. The galactic environment changes this distribution primarily through tidal shocks and dynamical friction. Our model explains, on a quantitative basis, the observed differences between the inner and outer populations of globular clusters in the Galaxy, M31, and M87. We can further calculate the amount of apparent brightening of the peak of the luminosity function due to destruction of low-mass clusters. Comparing the corrected peak with the center of the intrinsic distribution, we obtain distance moduli to the galaxies. Using this method we find dmM31 = 24.03 ± 0.23 and dmM87 = 30.81 ± 0.17, as compared to the current best estimates using other methods (dmM31 = 24.30 ± 0.20, dmM87 = 31.0 ± 0.1). This new method, coupled with Hubble Space Telescope observations, promises to provide an independent way of estimating distances to galaxies with recessional velocities 10,000 km s-1, or d 100 h-1 Mpc. The surprising consistency of the predicted and observed distances supports our initial Ansatz that the mass functions of globular clusters in the three galaxies, spanning a wide range of masses, were universal at the birth of these systems.
Sequential choice and non-Bayesian observational learning

Standard models of observational learning in settings of sequential choice have two key features. The first is that players make decisions by using Bayes' rule to update their beliefs about payoffs from a common prior. The second is that each agent's decision rule is common knowledge, so that subsequent players can draw inferences about unobserved private signals from observable actions. In this paper, I relax the first assumption while maintaining the second. In particular, I look at observational learning by players who choose between two actions using nonparametric methods for estimating payoffs. When players are identical and make inferences using the maximum score method, an informational cascade and herd must result. If players of different payoff types use kernel or nearest-neighbor methods, there are cases in which a cascade need not arise. If one does occur, it must be one in which all players, regardless of type, choose the same action. In some situations, these alternative learning rules perform better than Bayesian updating.
Mexican body mass index values in the late-19th-century American West.

Abstract No research has been done on the body mass index values of the 19th-century Mexican population. This paper introduces a new data source of 19th-century Mexican male inmates in American prisons and finds that the majority of Mexican body mass was in the normal range (18.5–24.9). Few Mexicans were underweight or obese by modern standards. Body mass varied little (0–0.9 units) by occupations possibly because criminals probably came from the lower end of the socioeconomic distribution; however, it did vary with crimes for which inmates were incarcerated.
Focusing of x-rays using micromachined silicon lobster eye lenses

We are developing a novel x-ray lens based on a 1D analogue of the optical system of the lobster's eye. The lobster eye lens consists of a large number of flat reflecting surfaces with 100 micrometers separation between adjacent surfaces. We have used silicon micromachining to fabricate arrays of 100 micrometers sized optical elements in oriented single crystal silicon wafers. We used a concentrated KOH solution to anisotropically etch single crystal silicon wafers; the resulting surfaces were aligned with the planes perpendicular to the face of the wafer. The pores were 50 micrometers wide and 800 micrometers deep, for an aspect ratio of 16:1. We report on the fabrication techniques and measurements of the surface microroughness of the etched surfaces.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Synthesis and evaluation of vancomycin and vancomycin aglycon analogues that bear modifications in the residue 3 asparagine

The synthesis and biological evaluation of a set of residue 3 analogues of vancomycin and its aglycon are described. These investigations follow from the promising biological activity of a protected and synthetically modified vancomycin aglycon analogue in which the asparagine side chain was modified to possess a nitrile, rather than a carboxamide. Although this modification typically was detrimental to antimicrobial activity, hydrophobic vancomycin aglycon analogues that lack a lipid anchor as well as the disaccharide are detailed that exhibit unusual potency against VanB, but not VanA, resistant bacteria.
Lateral diffusion of platinum through Pt2Si in Pt/Si couples

Abstract Lateral diffusion couples formed by depositing platinum islands on silicon layers on Al 2 O 3 were used in conjunction with scanning electron microprobe measurements to investigate the growth of platinum silicides in the temperature range 400–700 °C. The phase Pt 2 Si grows over a length of 4–30 μm with a rate proportional to the square root of time and an activation energy of approximately 1.3 eV. With samples containing 7 at.% Rh in the platinum, the growth rate of Pt 2 Si is reduced and the activation energy is increased to about 2.0 eV. In these Pt-7at.% Rh samples, electron-induced X-ray measurements indicate that rhodium remains in the original deposited region while both platinum and silicon diffuse in the formed Pt 2 Si region.
Instantaneous planar visualization of reacting supersonic flows using silane seeding

A new visualization technique for reacting flows has been developed. This technique, which is suitable for supersonic combustion flows, has been demonstrated on a scramjet combustor model. In this application, gaseous silane (SiH4) was added to the primary hydrogen fuel. When the fuel reacted, so did the (SiH4), producing silica (SiO2) particles in situ. The particles were illuminated with a laser sheet formed from a frequency-doubled Nd:YAG laser (532 nm) beam and the Mie scattering signal was imaged. These planar images of the silica Mie scattering provided instantaneous 'maps' of combustion progress within the turbulent reacting flowfield.
A microstrip nonreciprocal tunable YIG filter

A nonreciprocal tunable YIG filter in a microstrip configuration has been constructed which makes use of a novel method of generating a circularly, polarized field in the plane of a microstrip circuit. Nonreciprocities in excess of 40 dB have been obtained at X band with relatively low insertion loss and VSWR.
Magnetic symmetry of low-dimensional multiferroics and ferroelastics

Ferroics are materials with two or more “orientation” states with the ability to switch between them via an applied field. Based on spatial inversion and time reversal symmetry, there are four types of primary ferroics: ferroelectrics described by polarization P (a polar vector with broken spatial inversion symmetry), ferromagnets described by magnetization M (an axial vector with broken time reversal symmetry), ferrotoroidics described by torodization T (an axio-polar vector with both spatial inversion and time reversal symmetries broken) and ferroelastics described by strain e (a symmetric second rank polar tensor with neither spatial inversion nor time reversal symmetry broken but with broken rotational symmetry). Crystals exhibiting simultaneous ferroelectricity and magnetism are called magnetoelectrics. We analyze the magnetic symmetry of one- and two-dimensional (1D and 2D) multiferroics and enumerate 1D and 2D magnetoelectric point groups. We study a representative phase transition to such a point ...
A phosphorus-carbon bond cleavage reaction of coordinated trimethylphosphine in (PMe3)4Ru(OC6H4Me)2

Abstract A product resulting from cleavage of the PC bond in a trimethylphosphine ligand forms upon thermolysis of (PMe 3 ) 4 Ru(OC 6 H 4 Me) 2 ( 1 ) or addition of p -cresol to the orthometallated complex (PMe 3 ) 4 Ru(η 2 -OC 6 H 3 Me) ( 2 ). The trimethylphosphine ligand has been transformed to a dimethylarylphosphinite ligand in the product (PMe 3 ) 3 (η 2 -PMe 2 OC 6 H 3 )Ru(OC 6 H 4 Me) ( 3 ). Although complex 1 exists in equilibrium with complex 2 and free p -cresol at 65° C, kinetic evidence is presented indicating that complex 1 undergoes the PC cleavage reaction. An X-ray crystal structure analysis was performed on 3 . Crystal data at 25° C: a 11.8875(11), b 36.000(4), c 14.1207(13) A, β = 90.428(8)°, Z = 8, D calc 1.33 g/cm 3 ; space group P 2 1 / n .
Observation of Coherent Perovskite Particles in Growing Chromia Films

A Co–45 wt% Cr alloy that was implanted with 2×1016 yttrium ions/cm2 was oxidized at 1000°C in pure oxygen for 25 h. The chromia film that formed on the surface of the alloy had a grain size of 200 to 300 nm. Yttrium was segregated to the chromia grain boundaries, and both coherent and incoherent particles of YcrO3 (<2 vol% of the oxide film) were present in the chromia film.
Experimental investigation and thermodynamic modeling of the Nd–Ni system

Abstract The Nd–Ni system has been investigated via experiments and thermodynamic modeling. In the experimental part, alloys across the entire composition range were prepared by arc melting pure Nd and Ni slugs and annealing the alloys at 500 °C ( 70 at.% Ni) for 2 weeks. The annealed alloys were then subjected to differential scanning calorimetry and differential thermal analysis (DTA) measurements to determine the invariant reaction temperatures. Except for the peritectic reaction liquid + Nd 7 Ni 3 ↔ Nd 3 Ni and the polymorphous phase transformation of Nd 2 Ni 7 found in this study, all the other invariant reactions are confirmed to be the same types but with significant different temperatures as reported results. In the modeling part, the available phase equilibrium and thermodynamic data in the Nd–Ni system were analyzed by using thermodynamic models for the Gibbs energies of individual phases. An optimal set of thermodynamic parameters were obtained using WinPhad software. The calculated phase equilibria and thermodynamic properties from the model parameters were compared to the corresponding experimental data and good agreement was obtained.
On-line Optimal Control of a Class of Discrete Event Systems with Real-Time Constraints

We consider Discrete Event Systems (DES) involving tasks with real-time constraints and seek to control processing times so as to minimize a cost function subject to each task meeting its own constraint. It has been shown that the off-line version of this problem can be efficiently solved by the Critical Task Decomposition Algorithm (CTDA) (Mao et al., IEEE Trans Mobile Comput 6(6):678---688, 2007). In the on-line version, random task characteristics (e.g., arrival times) are not known in advance. To bypass this difficulty, worst-case analysis may be used. This, however, does not make use of probability distributions and results in an overly conservative solution. In this paper, we develop a new approach which does not rely on worst-case analysis but provides a "best solution in probability" efficiently obtained by estimating the probability distribution of sample-path-optimal solutions. We introduce a condition termed "non-singularity" under which the best solution in probability leads to the on-line optimal control. Numerical examples are included to illustrate our results and show substantial performance improvements over worst-case analysis.
Polarization measurements on single-step co-fired solid oxide fuel cells (SOFCs)

Abstract Anode-supported planar solid oxide fuel cells (SOFC) were successfully fabricated by a single step co-firing process. The cells comprised of a Ni + yttria-stabilized zirconia (YSZ) anode, a YSZ or scandia-stabilized zirconia (ScSZ) electrolyte, a (La0.85Ca0.15)0.97MnO3 (LCM) + YSZ cathode active layer, and an LCM cathode current collector layer. The fabrication process involved tape casting of the anode, screen printing of the electrolyte and the cathode, and single step co-firing of the green-state cells in the temperature range of 1300–1330 °C for 2 h. Cells were tested in the temperature range of 700–800 °C with humidified hydrogen as fuel and air as oxidant. Cell test results and polarization modeling showed that the polarization losses were dominated by the ohmic loss associated with the electrodes and the activation polarization of the cathode, and that the ohmic loss due to the ionic resistance of the electrolyte and the activation polarization of the anode were relatively insignificant. Ohmic resistance associated with the electrode was lowered by improving the electrical contact between the electrode and the current collector. Activation polarization of the cathode was reduced by the improvement of the microstructure of the cathode active layer and lowering the cell sintering temperature. The cell performance was further improved by increasing the porosity in the anode. As a result, the maximum power density of 1.5 W cm−2 was achieved at 800 °C with humidified hydrogen and air.