cssi/SciSciGPT-SciSciNet huggingface dataset:
Jet fuel droplet combustion with and without the convection

Combustion of stationary JP8 and JP8+100 fuel droplets were studied in low convectional environments for the first time. Although usage of these fuels is quite broad and significant, their fundamental physical properties are not well provided. Our goal is to provide practical parameters such as burning rate constants, burning times of jet fuel droplets by the use of the spherical symmetry in low convection. Furthermore, sooting propensity of JP8 and JP8+100 is reported by two approaches; burning in air and in a mixture of 30% oxygen and 70% helium (to suppress soot) at room temperature and 1atm. Low convection was achieved by performing experiments in a drop tower with a drag shield to reduce the gravity level. All experiments were fiber-supported and used the same experimental instruments to remove additional complexities. We also report a preliminary experimental result studied in natural convection (at room temperature and 1atm, air). The examined droplet diameters were from 0.44 to 0.49 mm for low convectional experiments and from 0.52 to 0.80 mm for natural convectional environment. Two different regions reveal very different results. In low gravity, significant droplet heating period and excessive soot for both fuels burning in air were observed. On the other hand, convection seems to overcome droplet heating by strong buoyancy, resulting in faster burning completion. Besides, the O/sub 2//He mixture helps us understand a role of soot on droplet burning by soot control. As a final note, droplet burning for all cases is nonlinear even after the initial heating period. Therefore, the burning rate is time-dependent and increases throughout the burning.
Social exclusion and the gender gap in education

Despite a sharp increase in the share of girls who enroll in, attend, and complete various levels of schooling, an educational gender gap remains in some countries. This paper argues that one explanation for this gender gap is the degree of social exclusion within these countries, as indicated by ethno-linguistic heterogeneity, which triggers both economic and psycho-social mechanisms to limit girls' schooling. Ethno-linguistic heterogeneity initially was applied to explaining lagging economic growth, but has emerged in the literature more recently to explain both civil conflict and public goods. This paper is a first application of the concept to explain gender gaps in education. The paper discusses the importance of female education for economic and social development, reviews the evidence regarding gender and ethnic differences in schooling, reviews the theoretical perspectives of various social science disciplines that seek to explain such differences, and tests the relevance of ethnic and linguistic heterogeneity in explaining cross-country differences in school attainment and learning. The study indicates that within-country ethnic and linguistic heterogeneity partly explains both national female primary school completion rates and gender differences in these rates, but only explains average national learning outcomes when national income measures are excluded.
Normal coordinates describing coupled oscillations in the gravitational field

The motion of a local source inducing small oscillations in the gravitational field is investigated and shown to exhibit pure rotational kinetic energy. Should the net affect of these slow, revolving oscillations cause large-scale rotations in spacetime it would certainly result in anomalous celestial accelerations. When this angular rotational frequency of spacetime is applied to the anomalous acceleration of the Pioneer 10/11 spacecrafts, the correlation is promising.
New constraints for heavy axion-like particles from supernovae

We derive new constraints on the coupling of heavy pseudoscalar (axion-like) particles to photons, based on the gamma ray flux expected from the decay of these particles into photons. After being produced in the supernova core, these heavy axion-like particles would escape and a fraction of them would decay into photons before reaching the Earth. We have calculated the expected flux on Earth of these photons from the supernovae SN 1987A and Cassiopeia A and compared our results to data from the Fermi Large Area Telescope. This analysis provides strong constraints on the parameter space for axion-like particles. For a particle mass of 100 MeV, we find that the Peccei-Quinn constant, fa, must be greater than about 1015?GeV. Alternatively, for fa = 1012?GeV, we exclude the mass region between approximately 100?eV and 1?GeV.
Geometrically Nonlinear Analysis of Adhesively Bonded Joints

A geometrically nonlinear finite element analysis of cohesive failure in typical joints is presented. Cracked-lap-shear joints were chosen for analysis. Results obtained from linear and nonlinear analysis show that nonlinear effects, due to large rotations, significantly affect the calculated mode 1, crack opening, and mode 2, inplane shear, strain-energy-release rates. The ratio of the mode 1 to mode 2 strain-energy-release rates (G1/G2) was found to be strongly affected by the adhesive modulus and the adherend thickness. The ratios between 0.2 and 0.8 can be obtained by varying adherend thickness and using either a single or double cracked-lap-shear specimen configuration. Debond growth rate data, together with the analysis, indicate that mode 1 strain-energy-release rate governs debond growth. Results from the present analysis agree well with experimentally measured joint opening displacements. Previously announced in STAR as N83-13497
Ground Delay Program Analytics with Behavioral Cloning and Inverse Reinforcement Learning

Historical data are used to build two types of models that predict Ground Delay Program implementation decisions and produce insights into how and why those decisions are made. More specifically, b...
Insurance Expansions: Do They Hurt Those They Are Designed To Help?

Seeking to redress health disparities across income and race, many policy-makers mandate health insurance benefits, presuming that equalized benefits will help equalize use of beneficial health services. This paper tests that presumption by measuring health care use by a diverse population with comprehensive health insurance. Focusing on use of mental health care and pharmaceuticals, it finds that even when insurance benefits and access are constant, whites and those with high incomes consume more of these benefits than other people do. This suggests that privileged classes extract more health care services even when everyone pays equal premiums for equal insurance coverage.
Incentive effects of bonus depreciation

Abstract This study examines the effect on capital expenditures of “bonus depreciation,” which was intended to stimulate such spending by allowing businesses to immediately expense a portion of the cost of qualified capital expenditures from late 2001 through 2004. After controlling for many previously documented determinants of capital expenditures, some of our results indicate that capital expenditures during bonus depreciation’s availability were greater than those during the time it was not available, consistent with the expected effect. However, other results indicate that bonus depreciation had an insignificant effect on capital expenditures. These mixed findings generally persist through several sensitivity analyses. We interpret these results as weakly supportive evidence that Congress attained its goal of stimulating capital spending.
On piecewise linear cell decompositions

We introduce a class of cell decompositions of PL manifolds and polyhedra which are more general than triangulations yet not as general as CW complexes; we propose calling them PLCW complexes. The main result is an analog of Alexander’s theorem: any two PLCW decompositions of the same polyhedron can be obtained from each other by a sequence of certain “elementary” moves. This definition is motivated by the needs of Topological Quantum Field Theory, especially extended theories as defined by Lurie.
An accurate two-dimensional theory of vibrations of isotropic, elastic plates

Abstract An infinite system of two-dimensional equations of motion of isotropic elastic plates with edge and corner conditions are deduced from the three-dimensional equations of elasticity by expansion of displacements in a series of trigonometrical functions and a linear function of the thickness coordinate of the plate. The linear term in the expansion is to accommodate the in-plane displacements induced by the rotation of the plate normal in low-frequency flexural motions. A system of first-order equations of flexural motions and accompanying boundary conditions are extracted from the infinite system. It is shown that the present system of equations is equivalent to the Mindlin's first-order equations, and the dispersion relation of straight-crested waves of the present theory is identical to that of the Mindlin's without introducing any corrections. Reduction of present equations and boundary conditions to those of classical plate theories of flexural motions is also presented.
On the Relationship between Transmission Power and Capacity of an Underwater Acoustic Communication Channel

The underwater acoustic channel is characterized by a path loss that depends not only on the transmission distance, but also on the signal frequency. As a consequence, transmission bandwidth depends on the transmission distance, a feature that distinguishes an underwater acoustic system from a terrestrial radio system. The exact relationship between power, transmission band, distance and capacity for the Gaussian noise scenario is a complicated one. This work provides a closed-form approximate model for (1) power consumption, (2) band-edge frequency and (3) bandwidth as functions of distance and capacity required for a data link. This approximate model is obtained by numerical evaluation of analytical results which takes into account physical models of acoustic propagation loss and ambient noise. The closed-form approximations may become useful tools in the design and analysis of underwater acoustic networks.
Schedulability criterion and performance analysis of coordinated schedulers

Inter-server coordinated scheduling is a mechanism for downstream nodes to increase or decrease a packet's priority according to the congestion incurred at upstream nodes. In this paper, we derive an end-to-end schedulability condition for a broad class of coordinated schedulers that includes Core-stateless Jitter Virtual Clock (CJVC) and Coordinated Earliest Deadline First (CEDF). In contrast to previous approaches, our technique purposely allows flows to violate their local priority indexes while still providing an end-to-end delay bound. We show that under a simple priority assignment scheme, coordinated schedulers can outperform WFQ schedulers, while replacing per-flow scheduling operations with a simple coordination rule. Finally, we illustrate the performance advantages of coordination through numerical examples and simulation experiments.
Cognitive and behavioral challenges in responding to climate change

Climate scientists have identified global warming as the most important environmental issue of our time, but it has taken over 20 years for the problem to penetrate the public discourse in even the most superficial manner. While some nations have done better than others, no nation has adequately reduced emissions and no nation has a base of public citizens that are sufficiently socially and politically engaged in response to climate change. This paper summarizes international and national differences in levels of knowledge and concern regarding climate change, and the existing explanations for the worldwide failure of public response to climate change, drawing from psychology, social psychology and sociology. On the whole, the widely presumed links between public access to information on climate change and levels of concern and action are not supported. The paper's key findings emphasize the presence of negative emotions in conjunction with global warming (fear, guilt, and helplessness), and the process of emotion management and cultural norms in the construction of a social reality in which climate change is held at arms length. Barriers in responding to climate change are placed into three broad categories: 1) psychological/conceptual, 2) social and cultural, and 3) structural (political economy). The author provides policy considerations and summarizes the policy implications of both psychological and conceptual barriers, and social and cultural barriers. An annotated bibliography is included.
Functionalized 5,6-dihydro-2H-1,2,6-thiadiazine 1,1-dioxides. Synthesis, structure and chemistry

Treatment of sulfamide 4a and aryl-substituted sulfamides 4b-e with ethyl 3,3-diethoxypropionate (13) provided a convenient procedure for the synthesis of functionalized 5,6-dihydro-2H-1,2,6-thiadiazine 1,1-dioxides 14. Key spectral properties of this novel class of heterocycles are reported. The generality and utility of this transformation is briefly explored.
Patient interest in video recording of colonoscopy: a survey.

AIM: To find if patients are interested in obtaining a video recording of their colonoscopy procedure. METHODS: We conducted a survey of outpatients presenting for colonoscopy regarding their interest in obtaining a video recording of their colonoscopy. RESULTS: Two hundred and forty-eight patients (mean age 57.9 years; 57% male) were surveyed. Two hundred and one patients (81%) were interested in obtaining a video recording. No significant predictors of patients’ interest in the video recording were identified. After reading a brief educational paragraph explaining missed lesions during colonoscopy, 135 patients (54%) were more interested in having a video recording, and none were less interested. One hundred and fifty-six patients (63%) were willing to pay for a video recording. In multivariable analyses, younger age was predictive of willingness to pay for a video recording. Prior history of colorectal cancer and a family history of colorectal cancer were predictive of willingness to pay a greater amount. CONCLUSION: Patients undergoing colonoscopy expressed substantial interest in obtaining a videorecording of their procedure. Awareness of missing lesions during colonoscopy increased interest in having a videorecording.
Benefit-Based Data Caching in Ad Hoc Networks

Data caching can significantly improve the efficiency of information access in a wireless ad hoc network by reducing the access latency and bandwidth usage. However, designing efficient distributed caching algorithms is nontrivial when network nodes have limited memory. In this article, we consider the cache placement problem of minimizing total data access cost in ad hoc networks with multiple data items and nodes with limited memory capacity. The above optimization problem is known to be NP-hard. Defining benefit as the reduction in total access cost, we present a polynomial-time centralized approximation algorithm that provably delivers a solution whose benefit is at least 1/4 (1/2 for uniform-size data items) of the optimal benefit. The approximation algorithm is amenable to localized distributed implementation, which is shown via simulations to perform close to the approximation algorithm. Our distributed algorithm naturally extends to networks with mobile nodes. We simulate our distributed algorithm using a network simulator (ns2) and demonstrate that it significantly outperforms another existing caching technique (by Yin and Cao [33]) in all important performance metrics. The performance differential is particularly large in more challenging scenarios such as higher access frequency and smaller memory.
Mitral valve prolapse: cardiac arrest with long-term survival.

Abstract Cardiac arrest has been reported in patients with mitral valve prolapse; however, clinical characteristics and survival information are limited since most of the cases reported include autopsy data. Nine patients (2 male, 7 female) with mitral valve prolapse were identified who had cardiac arrest; ventricular fibrillation was documented in 8 patients; resuscitation was unsuccessful in 2. Eight had a history of palpitations (months to 15 years duration) and ventricular arrhythmias, 3 had a history (5–15 years) of recurrent syncope, and 1 was totally asymptomatic. Cardiac catheterization-angiographic studies in 8 patients demonstrated normal coronary artery anatomy and mitral valve prolapse. All 9 patients had auscultatory and echocardiographic evidence of mitral valve prolapse. Seven survivors (6 still alive) were followed from 3 to 14 years after cardiac arrest. A subset of patients with mitral valve prolapse and cardiac arrest is described in whom past medical history is compatible with cardiac arrhythmias or syncope, and whose long-term prognosis appears better than patients with other causes of cardiac arrest.
Water-Soluble Calix[4]resorcarenes as Enantioselective NMR Shift Reagents for Aromatic Compounds

A tetra l-prolinylmethyl derivative of a tetra-sulfonated calix[4]resorcarene (1) is an effective chiral NMR solvating agent for water-soluble compounds with phenyl, pyridyl, bicyclic aromatic, or indole rings. These aromatic compounds form host−guest complexes with the calix[4]resorcarene in water. Complexation of substrates with the calix[4]resorcarene is likely promoted by hydrophobic effects, and bicyclic substrates have association constants with the calix[4]resorcarene larger than those of similar phenyl-containing compounds. Aromatic resonances of the substrates show substantial upfield shifts because of shielding from the aromatic rings of the calix[4]resorcarene, and several resonances in the 1H NMR spectra typically exhibit enantiomeric discrimination. The extent of enantiomeric discrimination depends in part on interactions of the substituent groups of the substrates with the prolinylmethyl groups of the calix[4]resorcarene. The effectiveness of a calix[4]resorcarene prepared from N-methyl-l-al...
Clonal Interference, Multiple Mutations, and Adaptation in Large Asexual Populations

Two important problems affect the ability of asexual populations to accumulate beneficial mutations and hence to adapt. First, clonal interference causes some beneficial mutations to be outcompeted by more-fit mutations that occur in the same genetic background. Second, multiple mutations occur in some individuals, so even mutations of large effect can be outcompeted unless they occur in a good genetic background that contains other beneficial mutations. In this article, we use a Monte Carlo simulation to study how these two factors influence the adaptation of asexual populations. We find that the results depend qualitatively on the shape of the distribution of the fitness effects of possible beneficial mutations. When this distribution falls off slower than exponentially, clonal interference alone reasonably describes which mutations dominate the adaptation, although it gives a misleading picture of the evolutionary dynamics. When the distribution falls off faster than exponentially, an analysis based on multiple mutations is more appropriate. Using our simulations, we are able to explore the limits of validity of both of these approaches, and we explore the complex dynamics in the regimes where neither one is fully applicable.
Shimura curve computations via K3 surfaces of Néron-Severi rank at least 19

In [E1] we introduced several computational challenges concerning Shimura curves, and some techniques to partly address them. The challenges are: obtain explicit equations for Shimura curves and natural maps between them; determine a Schwarzian equation on each curve (a.k.a. Picard-Fuchs equation, a linear second-order differential equation with a basis of solutions whose ratio inverts the quotient map from the upper half-plane to the curve); and locate CM (complex multiplication) points on the curves. We identified some curves, maps, and Schwarzian equations using the maps’ ramification behavior; located some CM points as images of fixed points of involutions; and conjecturally computed others by numerically solving the Schwarzian equations.
An experimental study of turbine vane heat transfer with leading edge and downstream film cooling

This paper presents the effects of downstream film cooling, with and without leading edge showerhead film cooling, on turbine-vane external heat transfer. Steady-state experimental measurements were made in a three-vane linear two-dimensional cascade. The principal independent parameters were maintained over ranges consistent with actual engine conditions. The test matrix was structured to provide an assessment of the independent influence of parameters of interest, namely, exit Mach number, exit Reynolds number, coolant-to-gas temperature ratio, and coolant-to-gas pressure ratio. The data obtained indicate that considerable cooling benefits can be achieved by utilizing downstream film cooling. The downstream film cooling process was shown to be a complex interaction of two competing mechanisms. The thermal dilution effect, associated with the injection of relatively cold fluid, results in a decrease in the heat transfer to the airfoil. Conversely, the turbulence augmentation, produced by the injection process, results in increased heat transfer to the airfoil.
Simulation of Coupled Viscous and Porous Flow Problems

Theoretical and numerical formulations are presented for the conjugate problem involving incompressible flow and flow in a saturated porous medium. The major focus of the work is the development of...
Moving Boundary Model for the Discharge of a LiCoO2 Electrode

A moving boundary model in a spherical LiCoO 2 particle is presented to account for the diffusion controlled phase transition in LiCoO 2 solid particles, and this model is incorporated into a porous electrode model for the LiCoO 2 electrode. The simulation results agree well with the experimental data of a LiCoO 2 electrode. A study of the flux distribution in the porous electrode shows that the phase transition phenomenon in the LiCoO 2 particles has a significant effect on the flux distribution by changing the solid phase diffusion resistance in the particles.
The dual origin of the terrestrial atmosphere

The origin of the terrestrial atmosphere is one of the most puzzling enigmas in the planetary sciences. It is suggested here that two sources contributed to its formation, fractionated nebular gases and accreted cometary volatiles. During terrestrial growth, a transient gas envelope was fractionated from nebular composition. This transient atmosphere was mixed with cometary material. The fractionation stage resulted in a high Xe/Kr ratio, with xenon being more isotopically fractionated than krypton. Comets delivered volatiles having low Xe/Kr ratios and solar isotopic compositions. The resulting atmosphere had a near-solar Xe/Kr ratio, almost unfractionated krypton delivered by comets, and fractionated xenon inherited from the fractionation episode. The dual origin therefore provides an elegant solution to the long-standing “missing xenon” paradox. It is demonstrated that such a model could explain the isotopic and elemental abundances of Ne, Ar, Kr, and Xe in the terrestrial atmosphere.
Technical Efficiency, Allocative Efficiency, and the Implementation of a Price Cap Plan in Telecommunications in the United States

Incentive regulation is designed to improve productive efficiency, enhance service quality and consumer welfare, and reduce the costs of regulation. The issue that is considered here is whether incentive regulation in the form of a price cap applicable to interstate access service to local loops in the telecommunications industry in the United States has resulted in an increase in the technical efficiency and allocative efficiency of local exchange carriers. The results suggest that for changes in technical efficiency, there is a definite randomness between 1985 and 1993 with technical efficiency increasing in some years and decreasing in others. Subsequent to 1993, however, there is a consistent improvement in technical efficiency. Given that incentive regulation in the form of price caps was implemented in 1991, it is likely that some portion of the improvement in technical efficiency subsequent to 1993 is attributable to incentive regulation.
LONG-TERM DYNAMICS AND THE ORBITAL INCLINATIONS OF THE CLASSICAL KUIPER BELT OBJECTS

We numerically integrated the orbits of 1458 particles in the region of the classical Kuiper belt (41 AU ≤ a ≤ 47 AU) to explore the role of dynamical instabilities in sculpting the inclination distribution of the classical Kuiper belt objects (KBOs). We find that the selective removal of low-inclination objects by overlapping secular resonances (ν_(17) and ν_(18)) acts to raise the mean inclination of the surviving population of particles over 4 billion yr of interactions with Jupiter, Saturn, Uranus, and Neptune, though these long-term dynamical effects do not themselves appear to explain the discovery of KBOs with inclinations near 30°. Our integrations also imply that after 3 billion yr of interaction with the massive planets, high-inclination KBOs more efficiently supply Neptune-encountering objects, the likely progenitors of short-period comets, Centaurs, and scattered KBOs. The secular resonances at low inclinations may indirectly cause this effect by weeding out objects unprotected by mean motion resonances during the first 3 billion yr.
Strong Motion from Surface Waves in Deep Sedimentary Basins

It is widely recognized that long-period surface waves generated by conversion of body waves at the boundaries of deep sedimentary basins make an important contribution to strong ground motion. The factors controlling the amplitude of such motion, however, are not widely understood. A study of pseudovelocity response spectra of strong-motion records from the Los Angeles Basin shows that late-arriving surface waves with group velocities of about 1 km/sec dominate the ground motion for periods of 3 sec and longer. The rate of amplitude decay for these waves is less than for the body waves and depends significantly on period, with smaller decay for longer periods. The amplitude can be modeled by the equation \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \[\mathrm{log}{\ }y=f(\mathbf{M},R\_{\mathrm{E}})+c+bR\_{\mathrm{B}}\] \end{document} where y is the pseudovelocity response, f ( M , R E) is an attenuation relation based on a general strong-motion data set, M is moment magnitude, R E is the distance from the source to the edge of the basin, R B is the distance from the edge of the basin to the recording site, and b and c are parameters fit to the data. The equation gives values larger by as much as a factor of 3 than given by the attenuation relationships based on general strong-motion data sets for the same source-site distance. It is clear that surface waves need to be taken into account in the design of long-period structures in deep sedimentary basins. The ground-motion levels specified by the earthquake provisions of current building codes, in California at least, accommodate the long-period ground motions from basin-edge-generated surface waves for periods of 5 sec and less and earthquakes with moment magnitudes of 7.5 or less located more than 20 km outside the basin. There may be problems at longer periods and for earthquakes located closer to the basin edge. The results of this study suggest that anelastic attenuation may need to be included in attempts to model long-period motion in deep sedimentary basins. To obtain better data on surface waves in the future, operators of strong-motion networks should take special care for the faithful recording of the long-period components of ground motion. It will also be necessary to insure that at least some selected recorders, once triggered, continue to operate for a time sufficient for the surface waves to traverse the basin. With velocities of about 1 km/sec, that time will be as long as 100 sec for a basin the size of the Los Angeles Basin.
The acetabular component: an elliptical monoblock alternative.

The major failure mode of cemented or noncemented acetabular fixation is osteolysis produced by biologic reaction to polyethylene and metallic debris. A monoblock acetabular noncemented component offers advantages in reducing the failure mechanism of acetabular cups. First, there is no extra-articular back surface polyethylene wear. Second, locking rings that may generate metallic debris are eliminated. Third, screw-holes, which decrease the surface area for ingrowth, are not needed, and pelvic entrance points for wear debris are eliminated. Fourth, an elliptical configuration allows better coaptation of the shell to the dome of the acetabulum. I have implanted >2,400 elliptical monoblock acetabular cups with a short-term follow-up of 6.5 years, with >4 years of follow-up in 840 hips. There have been no mechanical failures requiring revision. Four patients have been revised for recurrent hip instability, and one has been revised for infection. The need to convert to an acetabular component with screw fixation because of poor press-fit is <1%.
Lessons from action-research partnerships: LASA/Oxfam America 2004 Martin Diskin Memorial Lecture

Peer ReviewedTitle:Lessons from Action-Research Partnerships: LASA/Oxfam America 2004 Martin Diskin MemorialLectureAuthor:Fox, Jonathan A, UCSCPublication Date:02-01-2006Series:Reprint SeriesPublication Info:Reprint Series, Center for Global, International and Regional Studies, UC Santa CruzPermalink:http://escholarship.org/uc/item/65c0g8kwAdditional Info:Originally published as Jonathan Fox, "Lessons from Action-Research Partnerships,”Development in Practice, 16 (1), Feb., 2006Keywords:Globalization and Regulation, Social MovementsAbstract:Dr. Martin Diskin was a very engaged and vital member of the Latin American Studies Associationcommunity for some 30 or more years. Martin also gave us [at Oxfam America] 18 years of hislife . . . . He shaped over this period our commitment to human rights. He guided our grant-making in Latin America through several generations of institutional leaders and staff. (He wasaround longer than three directors and some 20 board members.) He encouraged our staff tospeak out forcefully against injustice and to position ourselves as a staunch critic of US foreignpolicy in Central America and Cuba. He demonstrated to us the value of linking research toadvocacy and being informed and strategic advocates. Most importantly, he modeled for us howto be courageous, tough-minded, outspoken and sail against the wind. . . He embodied thequintessential activist academic.Oxfam America wishes to remember Martin through this lectureship as a way of putting a #ag in theground in his honor that commemorates: his commitment to human rights activism; his propheticvoice in a world so in need of courage and hopeful vision; his commitment to academic rigor inservice of humanity; and his generosity as mentor and friend. (Remarks by Raymond Offenheiser,President, Oxfam America, at the Latin American Studies Association Congress, Chicago, IL, 25September 1998.)
Seeing the trees and their branches in the network is hard

Phylogenetic networks are a restricted class of directed acyclic graphs that model evolutionary histories in the presence of reticulate evolutionary events, such as horizontal gene transfer, hybrid speciation, and recombination. Characterizing a phylogenetic network as a collection of trees and their branches has long been the basis for several methods of reconstructing and evaluating phylogenetic networks. Further, these characterizations have been used to understand molecular sequence evolution on phylogenetic networks. In this paper, we address theoretical questions with regard to phylogenetic networks, their characterizations, and sequence evolution on them. In particular, we prove that the problem of deciding whether a given tree is contained inside a network is NP-complete. Further, we prove that the problem of deciding whether a branch of a given tree is also a branch of a given network is polynomially equivalent to that of deciding whether the evolution of a molecular character (site) on a network is governed by the infinite site model. Exploiting this equivalence, we establish the NP-completeness of both problems, and provide a parameterized algorithm that runs in time O(2^k^/^2n^2), where n is the total number of nodes and k is the number of recombination nodes in the network, which significantly improves upon the trivial brute-force O(2^kn) time algorithm for the problem. This reduction in time is significant, particularly when analyzing recombination hotspots.
Quarks in nuclei

Abstract I describe a hybrid model in which nuclei are treated as a system of six-quark bags, pions and baryons.
A Public Key Encryption Scheme Secure against Key Dependent Chosen Plaintext and Adaptive Chosen Ciphertext Attacks

Recently, at Crypto 2008, Boneh, Halevi, Hamburg, and Ostrovsky (BHHO) solved the long-standing open problem of "circular encryption," by presenting a public key encryption scheme and proving that it is semantically secure against key dependent chosen plaintext attack (KDM-CPA security) under standard assumptions (and without resorting to random oracles). However, they left as an open problem that of designing an encryption scheme that simultaneously provides security against both key dependent chosen plaintext and adaptive chosen ciphertext attack (KDM-CCA2 security). In this paper, we solve this problem. First, we show that by applying the Naor-Yung "double encryption" paradigm, one can combine any KDM-CPA secure scheme with any (ordinary) CCA2 secure scheme, along with an appropriate non-interactive zero-knowledge proof, to obtain a KDM-CCA2 secure scheme. Second, we give a concrete instantiation that makes use the above KDM-CPA secure scheme of BHHO, along with a generalization of the Cramer-Shoup CCA2 secure encryption scheme, and recently developed pairing-based NIZK proof systems. This instantiation increases the complexity of the BHHO scheme by just a small constant factor.
Conservation of the Stress Tensor in Perturbative Interacting Quantum Field Theory in Curved Spacetimes

We propose additional conditions (beyond those considered in our previous papers) that should be imposed on Wick products and time-ordered products of a free quantum scalar field in curved spacetime. These conditions arise from a simple "Principle of Perturbative Agreement": for interaction Lagrangians L1 that are such that the interacting field theory can be constructed exactly — as occurs when L1 is a "pure divergence" or when L1 is at most quadratic in the field and contains no more than two derivatives — then time-ordered products must be defined so that the perturbative solution for interacting fields obtained from the Bogoliubov formula agrees with the exact solution. The conditions derived from this principle include a version of the Leibniz rule (or "action Ward identity") and a condition on time-ordered products that contain a factor of the free field φ or the free stress-energy tensor Tab. The main results of our paper are (1) a proof that in spacetime dimensions greater than 2, our new conditions can be consistently imposed in addition to our previously considered conditions and (2) a proof that, if they are imposed, then for any polynomial interaction Lagrangian L1 (with no restriction on the number of derivatives appearing in L1), the stress-energy tensor Θab of the interacting theory will be conserved. Our work thereby establishes (in the context of perturbation theory) the conservation of stress-energy for an arbitrary interacting scalar field in curved spacetimes of dimension greater than 2. Our approach requires us to view time-ordered products as maps taking classical field expressions into the quantum field algebra rather than as maps taking Wick polynomials of the quantum field into the quantum field algebra.
Gauge Invariant Cosmological Perturbations

The physical interpretation of perturbations of homogeneous, isotropic cosmological models in the early Universe, when the perturbation is larger than the particle horizon, is clarified by defining a complete set of gauge-invariant variables. The linearized perturbation equations written in these variables are simpler than the usual versions, and easily accommodate an arbitrary background equation of state, entropy perturbations, and anisotropic pressure perturbations. Particular attention is paid to how a scalar (density) perturbation might be generated by stress perturbations at very early times, when the non-gauge-invariant perturbation in the density itself is ill-defined. The amplitude of the fractional energy density perturbation at the particle horizon cannot be larger, in order of magnitude, than the maximum ratio of the stress perturbation to the background energy density at any earlier time, unless the perturbation is inherent in the initial singularity.
TEMPO-catalyzed oxidation of benzylic alcohols to aldehydes with the H2O2/HBr/ionic liquid [bmim]PF6 system

Abstract A selective oxidation of benzylic alcohols to the corresponding aldehydes in room temperature ionic liquid was achieved by using TEMPO/HBr/H2O2 system, and both ether-insoluble acetamido-TEMPO and ionic liquid [bmim]PF6 can be successfully recovered and reused for the oxidation of the same (different) substrate.
Physics-based continuous simulation of long-term near-surface hydrologic response for the Coos Bay experimental catchment

[1] The study reported here employed the physics-based Integrated Hydrology Model (InHM) to conduct continuous hydrologic-response simulation from 1990 through 1996 for the Coos Bay experimental catchment. The uniqueness of the boundary-value problem used to simulate three sprinkling experiments was assessed, via model performance evaluation against observed piezometric and discharge data, for 33 events extracted from the continuous record. The InHM simulations could not adequately reproduce the distributed observed pore water pressures, suggesting that detailed characterization of the locations and connectivities of bedrock fractures is critical for future efforts designed to simulate distributed hydrologic response at the field scale for locations where bedrock fracture flow is important. The simulations presented here suggest the potential for interaction between the deeper water table and near-surface hydrologic response. The results reported herein suggest that while uniqueness can be reasonably achieved with respect to the integrated response (i.e., discharge), the integrated response uniqueness is no guarantee that the distributed response (i.e., pressure head) is either unique or well simulated.
Climate and Scale in Economic Growth

This paper introduces new data on climatic conditions to empirical tests of growth theories. We find that, since 1960, temperate countries have converged towards high levels of income while tropical nations have converged towards various income levels associated with economic scale and the extent of the market. These results hold for a wide range of tests. A plausible explanation is that temperate regions' growth was assisted by their climate, perhaps historically for their transition out of agriculture into sectors whose productivity converges across countries, while tropical countries' growth is relatively more dependent on gains from specialization and trade.
Magnet power supply system for the ALS storage ring and booster

The magnet power supply system is described by specification, design, hardware, and operating experience. A unique system for the 1 Hz, 1.5 GeV booster, where the wideband QF and QD power supplies track the dipole current to within 0.1% at injection will be detailed. AC distribution system considerations related to inverting the stored energy of the booster magnet back into the power grid will be discussed. The rationale for linear correctors and individual quad supplies (225 total units) will be placed within the context of the storage ring requirements. >
The role of NAFTA and returns to scale in export duration

While exports within NAFTA face a lower hazard, its onset has increased the hazard of exporting between the members, though intra-NAFTA exports still enjoy a lower hazard. There are differences in the timing of the effect of NAFTA across the three members. Unlike the effect on Canadian exports, the effect on Mexican and U.S. exports is persistent. Exports of increasing-returns-to-scale manufacturing products faced the highest hazard across all three members. The effect of NAFTA on the hazard of exporting each of the three returns to scale type of products is exporter specific with no uniform patterns.
Identification of multivariable stochastic linear systems via spectral analysis given time-domain data

Estimation of the parametric multiple-input-multiple-output (MIMO) infinite impulse response transfer function given time-domain input-output (IO) data is considered. We first propose a frequency-domain solution to the least-squares equation error multivariable system identification problem using the power spectrum and the cross-spectrum of the IO data to estimate the IO parametric transfer function. The proposed approach is shown to yield a unimodal performance surface and consistent identification in colored noise and the sufficient-order case. We then investigate an iterative pseudo-maximum likelihood approach and analyze its consistency under sufficient-order modeling. Finally, a computer simulation example is provided to illustrate the two approaches.
Discrete games with flexible information structures: an application to local grocery markets

Game-theoretic models are frequently employed to study strategic interaction between agents. Empirical research has focused on estimating payoff functions while maintaining strong assumptions regarding the information structure of the game. I show how to relax informational assumptions to enhance the credibility of empirical analysis in discrete games. I apply the method to data on the entry and exit patterns of grocery stores. The model provides useful bounds on equilibrium outcomes. In addition, the empirical analysis indicates that more restrictive informational assumptions can generate qualitatively misleading counterfactual outcomes.
Microwave-assisted N-arylation of a sulfoximine with aryl chlorides

N-Arylsulfoximines and related species could be prepared in good to excellent yield by the palladium-catalyzed coupling of 1 with aryl chlorides under the influence of microwave irradiation.
Switching through singularities

Asymptotic tracking is studied for systems which are not regular, that is, the relative degree is not well defined. For these systems, the input–output linearizing control law has singularities. We propose a tracking control law which switches between an approximate tracking law (Hauser et al., IEEE Trans. Automat. Control 37 (3) (1992) 392–398) close to the singularities, and an exact tracking law away from the singularities, and we study the applicability of this law based on the behavior of the system’s zero dynamics at the switching boundary. As in Hauser et al. (IEEE Trans. Automat. Control 37 (3) (1992) 392–398), the ball and beam example is used to motivate the study.
Efficiently identifying significant associations in genome-wide association studies

Over the past several years, genome wide association studies (GWAS) have implicated hundreds of genes in common disease. More recently, the GWAS approach has been utilized to identify regions of the genome which harbor variation affecting gene expression or expression quantitative trait loci (eQTLs). Unlike GWAS applied to clinical traits where only a handful of phenotypes are analyzed per study, in (eQTL) studies, tens of thousands of gene expression levels are measured and the GWAS approach is applied to each gene expression level. This leads to computing billions of statistical tests and requires substantial computational resources, particularly when applying novel statistical methods such as mixed-models. We introduce a novel two-stage testing procedure that identifies all of the significant associations more efficiently than testing all the SNPs. In the first-stage a small number of informative SNPs, or proxies, across the genome are tested. Based on their observed associations, our approach locates the regions which may contain significant SNPs and only tests additional SNPs from those regions. We show through simulations and analysis of real GWAS datasets that the proposed two-stage procedure increases the computational speed by a factor of 10. Additionally, efficient implementation of our software increases the computational speed relative to state of the art testing approaches by a factor of 75.
Subtype selective NMDA receptor antagonists: evaluation of some novel alkynyl analogues

A benzylpiperidine analogue with an acetylenic linker, 5-(3-[4-(4-fluorobenzyl)-piperidin-1-yl]-prop-1-ynyl)-1,3-dihydrobenzimidazol-2-one (3), was identified as a chemical lead with excellent activity at the NR1A/2B receptor (IC50=3 nM). Efforts to optimize this activity led to focused modifications around the structural motif of 3. The synthesis and SAR studies are discussed.
The Impact of School Resources on Women’s Earnings and Educational Attainment: Findings from the National Longitudinal Survey of Young Women

The article measures the impact of high school resources on women’s educational attainment and earnings. No link emerges between education and school resources—as measured by the pupil‐teacher ratio, spending per pupil, teachers’ starting salaries, or books per student. For white women, no significant connection between school resources and wages is found. But school inputs are in several cases significantly and positively related to black women’s wages. Wage elasticities with respect to school inputs are uniformly larger for black women. Finally, the impact of school resources on earnings remains constant or in some cases weakens as workers grow older.
Development of nonproprietary phosphine ligands for the Pd-catalyzed amination reaction

Abstract A new family of pyrazole and bi-pyrazole phosphine ligands are reported that perform efficiently in the Pd-catalyzed amination reaction. Of the ligands screened, ligand 1 emerged as the most compatible for couplings involving both primary and secondary amines with typical yields of 84–99%.
Optimizing hybrid metrology: rigorous implementation of Bayesian and combined regression

Hybrid metrology, e.g., the combination of several measurement techniques to determine critical dimensions, is an increasingly important approach to meet the needs of the semiconductor industry. A proper use of hybrid metrology may yield not only more reliable estimates for the quantitative characterization of 3-D structures but also a more realistic estimation of the corresponding uncertainties. Recent developments at the National Institute of Standards and Technology (NIST) feature the combination of optical critical dimension (OCD) measurements and scanning electron microscope (SEM) results. The hybrid methodology offers the potential to make measurements of essential 3-D attributes that may not be otherwise feasible. However, combining techniques gives rise to essential challenges in error analysis and comparing results from different instrument models, especially the effect of systematic and highly correlated errors in the measurement on the χ2 function that is minimized. Both hypothetical examples and measurement data are used to illustrate solutions to these challenges.