cssi/SciSciGPT-SciSciNet huggingface dataset:
Flow structure on a rotating plate

The flow structure on a rotating plate of low aspect ratio is characterized well after the onset of motion, such that transient effects are not significant, and only centripetal and Coriolis accelerations are present. Patterns of vorticity, velocity contours, and streamline topology are determined via quantitative imaging, in order to characterize the leading-edge vortex in relation to the overall flow structure. A stable leading-edge vortex is maintained over effective angles of attack from 30° to 75°, and at each angle of attack, its sectional structure at midspan is relatively insensitive to Reynolds number over the range from 3,600 to 14,500. The streamline topology, vorticity distribution, and circulation of the leading-edge vortex are determined as a function of angle of attack, and related to the velocity field oriented toward, and extending along, the leeward surface of the plate. The structure of the leading-edge vortex is classified into basic regimes along the span of the plate. Images of these regimes are complemented by patterns on crossflow planes, which indicate the influence of root and tip swirl, and spanwise flow along the leeward surface of the plate. Comparison with the equivalent of the purely translating plate, which does not induce the foregoing flow structure, further clarifies the effects of rotation.
WORKINGS OF THE MELTING POT: SOCIAL NETWORKS AND THE EVOLUTION OF POPULATION ATTRIBUTES*

This paper links the two nascent economic literatures on social networks and cultural assimilation by investigating the evolution of population attributes in a simple model where agents are influenced by their acquaintances. The main conclusion of the analysis is that attributes converge to a melting-pot equilibrium, where everyone is identical, provided the social network exhibits a sufficient degree of interconnectedness. When the model is extended to allow an expanding acquaintance set, convergence is guaranteed provided a weaker interconnectedness condition is satisfied, and convergence is rapid. If the intensity of interactions with acquaintances becomes endogenous, convergence (when it occurs) is slowed when agents prefer to interact with people like themselves and hastened when interaction with dissimilar agents is preferred.
Bridge number, Heegaard genus and non-integral Dehn surgery

We show there exists a linear function w: N->N with the following property. Let K be a hyperbolic knot in a hyperbolic 3-manifold M admitting a non-longitudinal S^3 surgery. If K is put into thin position with respect to a strongly irreducible, genus g Heegaard splitting of M then K intersects a thick level at most 2w(g) times. Typically, this shows that the bridge number of K with respect to this Heegaard splitting is at most w(g), and the tunnel number of K is at most w(g) + g-1.
Pressure Oscillations in Shuttle Solid Rocket Motors

All Shuttle Solid Rocket Motors (SRMs) exhibit low amplitude longitudinal pressure oscillations during motor burn. Although the oscillations have no known deleterious effect on motor ballistics, the acoustic pressure variations cause thrust oscillations that might affect Shuttle systems or components. The acoustic mode of greatest interest is the first or fundamental mode which, in the SRM, has a nominal frequency of 14-Hz. Oscillations hi the SRM are believed to be caused by coupling between large scale vortices and the acoustic modes of the motor chamber. The vortices are thought to be created in the region of the motor segment interfaces and are inherent in the design of the motor. In such a situation the usual approach is to measure the oscillations and assess their impact on any sensitive components through tests and analysis. Questionable components can be altered to survive the vibration environment. As motor firings occur, oscillations are monitored to determine whether there are changes in the nature of the oscillations. Since the first static test, SRMs have been equipped with instrumentation especially designed to acquire chamber pressure oscillation data. Data from the first SRM static tests were used to establish predicted upper bounds for the maximum amplitudes in the latter half of burn. Those bounds have been used as a basis for worst-case simulation scenarios by specialists in structural dynamics at NASA and Rockwell International and to provide a basis for evaluating data from individual motors which were tested subsequent to the original SRMs. This paper updates the upper bounds prediction the High Performance Motors (HPM) by including data from all static tests performed to date including both original SRMs and post Challenger SRMs or Reusable Solid Rocket Motors (RSRM) in which the joint design was changed. All together, this study examines 28 SRM motors, 16 HPM motors and 12 RSRM motors. Predicted upper bounds will be made for both the first and second longitudinal modes. The first mode upper bounds will be compared to the original seven standard rocket motors (STD). The results indicate that, although the upper bounds have increased, they are still within acceptable bounds.
Adaptive Compensation of Piezoelectric Sensoriactuators

An adaptive filter is used to estimate the feedthrough capacitance of a piezoelectric sensoriactuator in this work. The mechanical response of the piezostructure is resolved from the electrical response of the piezoelectric device through standard adaptive signal processing tech niques. Two common adaptive algorithms are reviewed for the given application: the LMS and the RLS. For spectrally white inputs the adaptation of the digital compensator yields a filter output which is proportional to the electrical response of the piezoelectric device. Thus, the remaining elec trical signal consists of the charge due to the mechanical response of the piezostructure. The adap tive filter converges to a combination of the feedthrough capacitance and the real portion of the mechanical piezostructure response, and the filter error is the quadrature component of the mechanical response. Preliminary results from the theoretical analysis and numerical simulations indicate that, under certain conditions, adaptive signal ...
Vortex Rings and the Plate Jet

It is postulated that the plates produced on a liquid jet by finite amplitude pressure fluctuations at the orifice are associated with the phenomenon of vortex-ring formation in the jet. An experimental determination of the pressure profile, using a specially designed pressure probe, in the presence of such pressure fluctuations, produced results consistent with the presence of vortex rings. For weak rings (small pressure fluctuation amplitude) the transverse pressure force produced by the vortex is small and can only trigger the capillary instability. With strong rings the force can overcome the restraining surface tension force, thus producing a plate on the jet. The low pressure produced inside the vortex ring causes fluid to flow in from adjoining parts of the jet and so mass modulation occurs. The author has already shown that the injector vibration produces a pressure variation upstream of the orifice. This in turn results in mass modulation which can trigger combustion instability in liquid fuel rocket engines. The vortex-ring theory provides considerable insight into the coupling between injector vibration (or any source of upstream pressure fluctuation) and the combustion process. Nomenclature AR = cross-sectional area of the vortex ring [Eq. (13)] a = radius of the vortex core E = energy of the vortex ring [Eq. (11)] g = gravity constant H = depth of the fluid I = impulse of the vortex ring [Eq. (8)] PC = pressure in the neighborhood of the vortex core po = pressure in the center of the liquid jet TO = radius of the vortex ring [Eq. (11)]; original jet radius
Instanton recursion relations for the effective prepotential in N=2 super-Yang–Mills

Linear recursion relations for the instanton corrections to the effective prepotential of N=2 supersymmetric gauge theories with an arbitrary number of hypermultiplets in the fundamental representation of an arbitrary classical gauge group are derived. The construction proceeds from the Seiberg–Witten solutions and the renormalization group type equations for the prepotential. Successive iterations of these recursion relations allow us to simply obtain instanton corrections to arbitrarily high order, which we exhibit explicitly up to 6th order. For gauge groups SU(2) and SU(3), our results agree with previous ones.
On the evaluation of Matsubara sums

Given a connected (multi)graph G, consisting of V vertices and I lines, we consider a class of multidimensional sums of the general form S G := ∑ ∞ n1=-∞ ∑ ∞ n2=-∞ ... ∑ ∞ ni=-∞ δ G (n 1 ,n 2 ,...,n I ;{N v }) / (n 2 1 + q 2 1 )(n 2 2+ q 2 2 ) ... (n 2 1 + q 2 1 ) , where the variables q i (i = 1, ... ,I) are real and positive and the variables N v (v = 1,..., V) are integer-valued. δ G (n 1 , n 2 , ..... n I ; {N v }) is a function valued in {0,1} which imposes a series of linear constraints among the summation variables n i , determined by the topology of the graph G. We prove that these sums, which we call Matsubara sums, can be explicitly evaluated by applying a G-dependent linear operator O' G to the evaluation of the integral obtained from S G by replacing the discrete variables n i by continuous real variables x i and replacing the sums by integrals.
Evolution with Changing Mutation Rates

This article considers the robustness of long run equilibria when mutation rates are not assumed to be constant over time. Particular attention is paid to the case where mutation rates decline to zero in the limit. It is found that if behavior is ergodic, then it corresponds to the long run equilibrium for the game. However, conditions for ergodicity become increasingly restrictive as population size increases.Journal of Economic LiteratureClassification Number: 72.
Growth of p-type hematite by atomic layer deposition and its utilization for improved solar water splitting.

Mg-doped hematite (α-Fe2O3) was synthesized by atomic layer deposition (ALD). The resulting material was identified as p-type with a hole concentration of ca. 1.7 × 1015 cm–3. When grown on n-type hematite, the p-type layer was found to create a built-in field that could be used to assist photoelectrochemical water splitting reactions. A nominal 200 mV turn-on voltage shift toward the cathodic direction was measured, which is comparable to what has been measured using water oxidation catalysts. This result suggests that it is possible to achieve desired energetics for solar water splitting directly on metal oxides through advanced material preparations. Similar approaches may be used to mitigate problems caused by energy mismatch between water redox potentials and the band edges of hematite and many other low-cost metal oxides, enabling practical solar water splitting as a means for solar energy storage.
Ligand-guided pathway selection in nickel-catalyzed couplings of enals and alkynes

Nickel-catalyzed couplings of enals and alkynes utilizing triethylborane as the reducing agent illustrate a significant dependence on ligand structure. Simple variation of monodentate phosphines allows selective access to alkylative couplings or reductive cycloadditions, while further variation of reaction conditions provides clean access to reductive couplings and redox-neutral couplings.
Large angle hadron correlations from medium-induced gluon radiation

Abstract Final state medium-induced gluon radiation in ultradense nuclear matter is examined and shown to favor large angle emission when compared to vacuum bremsstrahlung due to the suppression of collinear gluons. Perturbative expression for the contribution of its hadronic fragments to the back-to-back particle correlations is derived. It is found that in the limit of large jet energy loss gluon radiation determines the yield and angular distribution of | Δ φ | ⩾ π 2 dihadrons to high transverse momenta p T 2 of the associated particles. Clear transition from enhancement to suppression of the away-side hadron correlations is established at moderate p T 2 and its experimentally accessible features are predicted versus the trigger particle momentum p T 1 .
Enhancement Of Microchannel Plate Gain By Deposition Of CsI On The Channel Walls

At LLNL microchannel plate (MCP) detectors of x rays have been in use for several years. The voltage is applied by a coating on the MCP which needs to be thick enough that the propagation losses are small. To enhance the gain loss of a thick Au coating CsI is used to enhance the gain and quantum efficiency of the MCP. We have recently discovered that thick coatings of CsI (2 gm) in both the front and back side of the MCP (normal to bias angle) greatly increases the gain.
Stationary and nonstationary strategies in Hotelling's model of spatial competition with repeated pricing decisions

This paper examines Hotelling's model of location with linear transportation cost. Existence of pure strategy subgame perfect equilibria in the infinitely repeated price game with fixed locations is proved. These subgame perfect equilibria have a stick and carrot structure. Given firm locations, there are discount factors sufficiently high that there is a subgame perfect equilibrium with a two-phase structure. Given the discount factors, there are stationary subgame perfect equilibria for a wide range of locations. However, for some pairs of location, no symmetric simple penal code exists, all subgame perfect profiles are nonstationary, and there is only one seller in the market in infinitely many periods.
Atom transfer radical addition and polymerization reactions catalyzed by ppm amounts of copper complexes

Over the past decade, copper-catalyzed atom transfer radical polymerization (ATRP) has had a tremendous impact on the synthesis of polymeric materials with well defined compositions, architectures and functionalities. Apart from synthetic aspects of ATRP, considerable effort has also been devoted to structural and mechanistic understanding of copper complexes involved in ATRP, as well as development of methodologies to decrease the amount of catalyst needed in these systems. This tutorial review reports on recent advances in the area of catalyst regeneration in ATRP and mechanistically similar atom transfer radical addition (ATRA) using environmentally benign reducing agents. The outlined processes termed ARGET (activators regenerated by electron transfer) and ICAR (initiators for continuous activator regeneration) ATRP enable the synthesis of well-defined (co)polymers and single addition adducts using very low concentrations of copper catalysts (1–100 ppm). Recent developments in this area could have profound industrial implications on the synthesis of well-defined polymeric materials and small organic molecules.
Why don't bull moose eat during the rut?

Reduced forage intake by males is generally believed to coincide with the peak of rutting activities in many ungulates. Activity budgets of bull moose (Alces alces) in Denali National Park and Preserve (DNPP) and Isle Royale National Park (IRNP) were analyzed to assess: (1) if time spent foraging decreased during the rut; (2) the timing of reduced forage intake; (3) whether there was variation in feeding time among bulls of varying size; and (4) the proximate mechanism and adaptive value of reduced forage intake. Time spent feeding by bull moose began to decrease around 1 September: large bulls completely ceased feeding for approximately 2 weeks, with median dates of feeding cessation at 18 and 20 September for IRNP and DNPP, respectively. Small bulls fed at reduced rates, but did not cease feeding. Although large bulls in both study sites spent large amounts of time engaged in social behavior during the period of appetite suppression, much of their active time was also spent standing inattentive, i.e., engaged in no activity (45.5% in IRNP, 29.8% in DNPP), suggesting that a constraint in time budgets did not limit opportunities to feed. Forage intake reduction is more likely mediated through a physiological mechanism. Feeding cessation did not coincide with the peak of the rut: at DNPP the median date of feeding cessation was significantly earlier than the median date of breeding behavior and fighting. The timing of feeding cessation coincided with that of scent-urination at both study sites, raising the possibility that appetite suppression may be a byproduct of physiological processes associated with chemical communication.
Water under pressure

Water under pressure is investigated by first principles molecular dynamics, with a focus on the changes in hydrogen bonding and the oxygen network in the nondissociative regime. At a pressure of 10 GPa and a temperature of 600 K, which is close to the freezing point, no appreciable molecular dissociation is observed in the simulations. However, the structure of water is substantially altered from that at ambient conditions. The liquid exhibits a much larger coordination of oxygen atoms, an essential weakening of hydrogen bonding, and sizable changes in the density of electronic states close to the Fermi level. Our results provide new structural data for direct comparison with future experiments. (c) 2000 The American Physical Society.
Rh(I)-Catalyzed Olefin Hydroarylation with Electron-Deficient Perfluoroarenes

Assisted by a partially aqueous media, a catalyst system of [Rh(cod)(OH)]2 and DPPBenzene ligand effectively promotes direct conjugate additions by perfluoroarenes. This formal C−H alkylation process represents a rare example of olefin hydroarylation with electron-deficient arenes. The catalyst system can be modified to selectively form the corresponding olefination products under anhydrous conditions.
Collective Memory Meets Organizational Identity: Remembering to Forget in a Firm's Rhetorical History

Much organizational identity research has grappled with the question of identity emergence or change. Yet the question of identity endurance is equally puzzling. Relying primarily on an analysis of...
Regional differences in lectin binding patterns of vestibular hair cells

Surface glycoconjugates of hair cells and supporting cells in the vestibular endorgans of the bullfrog were identified using biotinylated lectins with different carbohydrate specificities. Lectin binding in hair cells was consistent with the presence of glucose and mannose (CON A), galactose (RCA-I), N-acetylglucosamine (WGA), N-acetylgalactosamine (VVA), but not fucose (UEA-I) residues. Hair cells in the bullfrog sacculus, unlike those in the utriculus and semicircular canals, did not strain for N-acetylglucosamine (WGA) or N-acetylgalactosamine (VVA). By contrast, WGA and, to a lesser extent, VVA, differentially stained utricular and semicircular canal hair cells, labeling hair cells located in peripheral, but not central, regions. In mammals, WGA uniformly labeled Type I hair cells while labeling, as in the bullfrog, Type II hair cells only in peripheral regions. These regional variations were retained after enzymatic digestion. We conclude that vestibular hair cells differ in their surface glycoconjugates and that differences in lectin binding patterns can be used to identify hair cell types and to infer the epithelial origin of isolated vestibular hair cells.
Calibrating the Employment Effects of Trade

The one-sector model of monopolistic competition and intraindustry trade is merged with the Shapiro–Stiglitz model of efficiency wages to show that introducing trade increases employment in both countries. The intuition is that even when employment is held constant, trade improves worker welfare via increased variety of available goods. The increase in worker welfare relaxes the efficiency wage constraint, permitting an increase in employment. The increase in employment magnifies the benefits of trade. The model is calibrated to US data to estimate the employment effects of eliminating all trade and eliminating trade with Mexico and Canada.
TGF-β1 enhances cardiomyogenic differentiation of skeletal muscle-derived adult primitive cells

The optimal medium for cardiac differentiation of adult primitive cells remains to be established. We quantitatively compared the efficacy of IGF-1, dynorphin B, insulin, oxytocin, bFGF, and TGF-β1 in inducing cardiomyogenic differentiation. Adult mouse skeletal muscle-derived Sca1+/CD45-/c-kit-/Thy-1+ (SM+) and Sca1-/CD45-/c-kit-/Thy-1+ (SM-) cells were cultured in basic medium (BM; DMEM, FBS, IGF-1, dynorphin B) alone and BM supplemented with insulin, oxytocin, bFGF, or TGF-β1. Cardiac differentiation was evaluated by the expression of cardiac-specific markers at the mRNA (qRT-PCR) and protein (immunocytochemistry) levels. BM+TGF-β1 upregulated mRNA expression of Nkx2.5 and GATA-4 after 4 days and Myl2 after 9 days. After 30 days, BM+TGF-β1 induced the greatest extent of cardiac differentiation (by morphology and expression of cardiac markers) in SM- cells. We conclude that TGF-β1 enhances cardiomyogenic differentiation in skeletal muscle-derived adult primitive cells. This strategy may be utilized to induce cardiac differentiation as well as to examine the cardiomyogenic potential of adult tissue-derived stem/progenitor cells.
The status of US Teraflops-scale projects

The current status of United States projects pursuing Teraflops-scale computing resources for lattice field theory is discussed. Two projects are in existence at this time: the Multidisciplinary Teraflops Project, incorporating the physicists of the QCD Teraflops Collaboration, and a smaller project, centered at Columbia, involving the design and construction of a 0.8 Teraflops computer primarily for QCD.
ST2 in Emergency Department Chest Pain Patients With Potential Acute Coronary Syndromes

Study objective The emergency department (ED) evaluation of potential acute coronary syndrome patients is limited by the initial sensitivity of cell injury biochemical markers. Increased ST2, a protein thought to participate in the response to cardiovascular injury, has been noted to be prognostic in patients with acute myocardial infarction. We hypothesize that ST2 would be increased at presentation in ED chest pain patients with myocardial ischemia, thus allowing for the early identification of acute myocardial infarction, acute coronary syndrome, and 30-day adverse cardiovascular events, with an area under the receiver operator characteristic curve (AUC) for each outcome of greater than 0.7. Methods Patients aged 25 years or older and presenting to the ED with chest pain prompting an ECG were prospectively enrolled. ST2 was measured at presentation. Main outcomes were acute myocardial infarction, acute coronary syndrome, and 30-day events (death, acute myocardial infarction, or revascularization). Median ST2 values were calculated for patients with and without each outcome. The AUCs were calculated for each outcome. In a post hoc analysis, patients with outlying increased ST2 values were examined to determine possible alternative causes for ST2 expression. Results There were 348 patients enrolled. The outcomes were acute myocardial infarction 17 patients (4.9%), acute coronary syndrome 39 (11.2%), and 30-day events 23 (6.6%). The AUCs for acute myocardial infarction, acute coronary syndrome, and 30-day events were 0.636, 0.630, and 0.579, respectively. ST2 did not predict acute myocardial infarction, acute coronary syndrome, or 30-day events. It was increased in a small number of patients with pulmonary disease, notably, pulmonary emboli, systemic infection or inflammation, and alcohol abuse. Conclusion ST2 was not of value in the evaluation of ED patients with potential acute coronary syndrome.
Renormalized classical non-linear hydrodynamics quantum mode coupling and quantum theory of interacting phonons

Abstract Motivated by the second law a renormalization scheme is introduced within the framework of classical, non-linear hydrodynamics that enables one to directly calculate the essential results of the quantum theory of interacting phonons. Consequences for quantum mode coupling and the quantum fluctuation dissipation theorem are discussed.
A Constant Bar Fraction out to Redshift z ~ 1 in the Advanced Camera for Surveys Field of the Tadpole Galaxy

Barlike structures were investigated in a sample of 186 disk galaxies larger than 05 that are in the I-band image of the Tadpole galaxy taken with the Hubble Space Telescope Advanced Camera for Surveys. We found 22 clear cases of barred galaxies, 21 galaxies with small bars that appear primarily as isophotal twists in a contour plot, and 11 cases of peculiar bars in clump-cluster galaxies, which are face-on versions of chain galaxies. The latter bars are probably young, as the galaxies contain only weak interclump emission. Four of the clearly barred galaxies at z ~ 0.8-1.2 have grand-design spirals. The bar fraction was determined as a function of galaxy inclination and compared with the analogous distribution in the local universe. The bar fraction was also determined as a function of galaxy angular size. These distributions suggest that inclination and resolution effects obscure nearly half of the bars in our sample. The bar fraction was also determined as a function of redshift. We found a nearly constant bar fraction of 0.23 ± 0.03 from z ~ 0 to z = 1.1. When corrected for inclination and size effects, this fraction is comparable to the bar fraction in the local universe, ~0.4, which we tabulated for all bar and Hubble types in the Third Reference Catalogue of Bright Galaxies. The average major axis of a barred galaxy in our sample is ~10 kpc after correcting for redshift with a Λ-dominated cold dark matter cosmology. The average exponential scale length is ~2 kpc. These are half the sizes of local barred galaxies and not likely to be influenced much by cosmological dimming, because the high-z galaxies are intrinsically brighter. We conclude that galaxy bars were present in normal abundance at least ~8 Gyr ago (z ~ 1); the bars in clump-cluster galaxies may have formed from gaseous disk instabilities and star formation rather than stellar disk instabilities, and bar dissolution cannot be common during a Hubble time unless the bar formation rate is comparable to the dissolution rate. If galaxy interactions trigger bar formation more than bar destruction, then the higher interaction rate in the past suggests relatively few bars actually dissolved in a Hubble time.
The Cultural Affinity Hypothesis and Mortgage Lending Decisions

This paper conducts an empirical analysis of the cultural affinity hypothesis put forth by Calomiris, et al. (1994) in the mortgage lending market. This hypothesis implies that white loan officers, because of a lack of familiarity with minority applicants, will rely more heavily on characteristics that can be observed at low cost (e.g., objective loan application measures) in evaluating the creditworthiness of minority applicants relative to white applicants. Using a cleansed sample of 1,991 loan applications drawn from data collected by the Federal Reserve Bank of Boston, the results of the analysis were consistent with the cultural affinity hypothesis. In particular, we found that marginal black and Hispanic applicants appeared to be held to higher quantitative standards on such objective factors as credit history and debt obligation ratios than were similarly situated marginal white applicants.
Inflation in Argentina : stop and go since the Austral plan

The Austral plan, launched in 1985, was Argentina's most recent stabilization strategy for reducing high inflation. A heterodox program, it combined orthodox components - tight fiscal policy and monetary restraint - with less conventional wage and price controls. The Austral plan failed to bring inflation down on a sustained basis, but it provided useful lessons about the design of heterodox stabilization programs, the difficulties of sustaining this type of effort, and the consequences of failure.
Three-Dimensional Numerical Simulations of Circular Cylinders Undergoing Two Degree-of-Freedom Vortex-Induced Vibrations

In an effort to gain a better understanding of vortex-induced vibrations (VIV), we present three-dimensional numerical simulations of VIV of circular cylinders. We consider operating conditions that correspond to a Reynolds number of 10 5 , low structural mass and damping (m*= 1.0, ζ*=0.005), a reduced velocity of U*=6.0, and allow for two degree-of-freedom (X and Y) motion. The numerical implementation makes use of overset (Chimera) grids, in a multiple block environment where the workload associated with the blocks is distributed among multiple processors working in parallel. The three-dimensional grid around the cylinder is allowed to undergo arbitrary motions with respect to fixed background grids, eliminating the need for grid regeneration as the structure moves on the fluid mesh.
Fetal surgery for myelomeningocele

Myelomeningocele is a common birth defect that is associated with significant lifelong morbidity. Despite improvements in technology and overall patient care, little progress has been made in the postnatal surgical management of the child with spina bifida. Postnatal surgery is aimed at covering the exposed spinal cord and preventing infection. Numerous interventions for ventricular shunts, tethered cord, scoliosis, incontinence, urologic complications, and extremity anomalies are frequently required. Although myelomeningocele is a nonlethal fetal anomaly, the limitations with current postnatal treatment strategies has led to extensive investigation of prenatal treatment options. This article outlines the rationale for fetal intervention and discusses the preliminary experience with human fetal myelomeningocele surgery.
Towards accurate three-dimensional simulation of dense multi-phase flows using cylindrical coordinates

Most industrial scale fluidized-bed reactors are cylindrical, and the cylindrical coordinate system is a natural choice for their CFD simulation. There are, however, subtle complexities associated with this choice when using the Two-Fluid Model. The center of the grid forms a computational “boundary” and requires special treatment. Conventionally, a free slip no-normal flow condition has been used which does not predict the hydrodynamics accurately even when predicted parameters are in good agreement with measurement. Another difficulty is posed by the extremely small cells near the grid center, especially when simulating small scale experiments. The presence of these small cells raises concerns over the applicability of the Two-Fluid Model and is known to result in slow simulation convergence. These issues are addressed in the present study and appropriate solutions are proposed including the centerline treatment and the use of a non-uniform grid. Finally, the study compares the Cartesian grid with the cylindrical grid for application to fluidization. It is shown that simulating a cylindrical bed using the cylindrical grid is not only more accurate but also more computationally efficient. The analysis presented along with the proven computational efficiency of the cylindrical grid is especially significant considering that modeling commercial scale reactors, with multiple solid phases and chemical reactions, not only will require accurate description of the fluidization process but will also be exceedingly expensive in terms of computational cost.
Interpolation of sparse multivariate polynomials over large finite fields with applications

Abstract We develop a Las Vegas-randomized algorithm which performs interpolation of sparse multivariate polynomials over finite fields. Our algorithm can be viewed as the first successful adaptation of the sparse polynomial interpolation algorithm for the complex field developed by M. Ben-Or and P. Tiwari (1988, in “Proceedings of the 20th ACM Symposium on the Theory of Computing,” pp. 301–309, Assoc. Comput. Mach., New York) to the case of finite fields. It improves upon a previous result by D. Y. Grigoriev, M. Karpinski, and M. F. Singer (1990, SIAM J. Comput.19, 1059–1063) and is by far the most time efficient algorithm (time and processor efficient parallel algorithm) for the problem when the finite field is large. As applications, we obtain Monte Carlo-randomized parallel algorithms for sparse multivariate polynomial factorization and GCD over finite fields. The efficiency of these algorithms improves upon that of the previously known algorithms for the respective problems.
Transfers and environmental co-benefits of carbon sequestration in agricultural soils : retiring agricultural land in the Upper Mississippi River Basin

This study investigates the carbon sequestration potential and co-benefits from policies aimed at retiring agricultural land in the Upper Mississippi River Basin, a large, heavily agricultural area. In addition to empirically measuring environmental co-benefits, we also compute economic transfers, which have sometimes been referred to as a co-benefit. Very little empirical work measuring the potential magnitude of these transfers has previously been undertaken. We compare and contrast alternative targeting schemes. We find that there are considerable amount of co-benefits and transfers and that the geographic distribution of co-benefits and transfers varies significantly with the specific benefit targeted. This implies that policy design related to targeting can have very important implications for both environmental conditions and income distributions in sub-regions. Issues related to policy design in the presence of co-benefits are considered.
Additional aspects of the Stackelberg strategy in nonzero-sum games

The Stackelberg strategy in nonzero-sum games is a reasonable solution concept for games where, either due to lack of information on the part of one player about the performance function of the other, or due to different speeds in computing the strategies, or due to differences in size or strength, one player dominates the entire game by imposing a solution which is favorable to himself. This paper discusses some properties of this solution concept when the players use controls that are functions of the state variables of the game in addition to time. The difficulties in determining such controls are also pointed out. A simple two-stage finite state discrete game is used to illustrate these properties.
High-calorie-expenditure exercise: a new approach to cardiac rehabilitation for overweight coronary patients.

Background— More than 80% of patients entering cardiac rehabilitation (CR) are overweight, and >50% have metabolic syndrome. Current CR exercise protocols result in little weight loss and minimal changes in cardiac risk factors. We sought to design an exercise protocol that would lead to greater weight loss and risk factor change. Methods and Results— We performed a randomized controlled clinical trial to evaluate the effect of high-calorie-expenditure exercise (3000- to 3500-kcal/wk exercise-related energy expenditure) compared with standard CR exercise (7 to 800 kcal/wk) on weight loss and risk factors in 74 overweight patients with coronary heart disease. Both groups were counseled for weight loss and taking evidence-based preventive medications. High-calorie-expenditure exercise resulted in double the weight loss (8.2±4 versus 3.7±5 kg; P<0.001) and fat mass loss (5.9±4 versus 2.8±3 kg; P<0.001) and a greater waist reduction (−7±5 versus −5±5 cm; P=0.02) than standard CR exercise at 5 months. High-cal...
The uniqueness of tangent cones for Yang–Mills connections with isolated singularities

We proved a uniqueness theorem of tangent connections for a Yang–Mills connection with an isolated singularity with a quadratic growth of the curvature at the singularity. We also obtained control over the rate of the asymptotic convergence of the connection to the tangent connection if furthermore the connection is stationary or the tangent connection is integrable, with a stronger result in the latter case. There are parallel results for the cones at infinity of a Yang–Mills connection on an asymptotically flat manifold. We also gave an application of our methods to the Yang–Mills flow and proved that the Yang–Mills flow exists for all time and has asymptotic limit if the initial value is close to a smooth local minimizer of the Yang–Mills functional.
Effect of contact induced states on minimum conductivity in graphene

The objective of this paper is to point out that contact induced states can help explain the structure dependence of the minimum conductivity observed experimentally. Contact induced states are similar to the well-known metal induced gap states in metal-semiconductor Schottky junctions, which typically penetrate a few atomic lengths into the semiconductor, while the depth of penetration decreases with increasing band gap. However, in graphene we find that these states penetrate a much longer distance of the order of the width of the contacts. As a result, ballistic graphene samples with a length less than their width at Dirac points can exhibit a length-dependent resistance that is not ``Ohmic'' in origin but arises from a reduced role of contact induced states. While earlier theoretical works have shown that ballistic graphene samples can exhibit a minimum conductivity, our numerical results demonstrate that this minimum conductivity depends strongly on the structure and configuration of the channel and contacts. In diffusive samples, our results still show that the contact induced states effect needs to be taken into account in explaining minimum conductivity and its dependence on the structure (two terminal vs four terminal) and configuration used.
Enantioselective Synthesis of α-Tertiary Hydroxyaldehydes by Palladium-Catalyzed Asymmetric Allylic Alkylation of Enolates

Chiral α-tertiary hydroxyaldehydes are very versatile building blocks in synthetic chemistry. Herein, we report the first examples of a catalytic asymmetric protocol for the synthesis of such compounds from readily available α-halo or α-hydroxy ketones or enol silyl ethers with excellent yields and enantioselectivity. Its synthetic utility is demonstrated in the short, efficient formal synthesis of (S)-oxybutynin. In this process, the chiral ligand controls the regioselectivity as well as the enantioselectivity.
On perturbative instability of Pope-Warner solutions on Sasaki-Einstein manifolds

Given a Sasaki-Einstein manifold, M7, there is the N = 2 supersymmetric AdS4 ×M7 Freund-Rubin solution of eleven-dimensional supergravity and the correspond- ing non-supersymmetric solutions: the perturbatively stable skew-whiffed solution, the perturbatively unstable Englert solution, and the Pope-Warner solution, which is known to be perturbatively unstable when M7 is the seven-sphere or, more generally, a tri-Sasakian manifold. We show that similar perturbative instability of the Pope-Warner solution will arise for any regular Sasaki-Einstein manifold, M7, admitting a basic, primitive, trans- verse (1,1)-eigenform of the Hodge-de Rham Laplacian with the eigenvalue in the range between 2(9 − 4 √ 3) and 2(9 + 4 √ 3). Existence of such (1,1)-forms on all homogeneous Sasaki-Einstein manifolds can be shown explicitly using the Kahler quotient construction or the standard harmonic expansion. The latter shows that the instability arises from the coupling between the Pope-Warner background and Kaluza-Klein scalar modes that at the supersymmetric point lie in a long Z-vector supermultiplet. We also verify that the insta- bility persists for the orbifolds of homogeneous Sasaki-Einstein manifolds that have been discussed recently.
The Three-dimensional Structure of a Sunspot Magnetic Field

We report on observations of the three-dimensional structure of a sunspot magnetic field from the photosphere to the chromosphere, obtained with the new visible/infrared spectropolarimeter SPINOR. The observations, interpreted with a non-LTE modeling technique, reveal a surprisingly complex topology with areas of opposite-sign torsion, suggesting that flux ropes of opposite helicity may coexist together in the same spot.
Robust Range-Only Beacon Localization

In this paper, we present a system capable of simultaneously estimating the position of an autonomous underwater vehicle (AUV) and the positions of stationary range-only beacons. Notably, our system does not require beacon positions a priori, and our system performs well even when range measurements are severely degraded by noise and outliers. We present a powerful outlier rejection method that can identify groups of range measurements that are consistent with each other, and a method for initializing beacon positions in an extended Kalman filter (EKF). We have successfully applied our algorithms to real-world data and have demonstrated a simultaneous localization and mapping (SLAM) system whose navigation performance is comparable to that of systems that assume known beacon locations
Comparison of ELM heat loads in snowflake and standard divertors

Abstract An analysis is given of the impact of the tokamak divertor magnetic structure on the temporal and spatial divertor heat flux from edge localized modes (ELMs). Two configurations are studied: the standard divertor where the poloidal magnetic field ( B p ) varies linearly with distance ( r ) from the magnetic null and the snowflake where B p varies quadratically with r . Both one- and two-dimensional models are used to analyze the effect of the longer magnetic field length between the midplane and the divertor plate for the snowflake that causes a temporal dilation of the ELM divertor heat flux. A second effect discussed is the appearance of a broad region near the null point where the poloidal plasma beta can substantially exceed unity, especially for the snowflake configuration during the ELM; such a condition is likely to drive additional radial ELM transport.
The Maximal Generic Number of Pure Nash Equilibria

Abstract For finite pure strategy setsS1, …, SnifE⊂S=S1×…×Snis the set of pure strategy Nash equilibria for an open set of payoffs vectors, then #E⩽#S/(maxi#Si). There is an open set of payoff vectors for which there are #S/(maxi#Si) pure Nash equilibria.Journal of Economic Literature, Classification Number C72.
Weakly relative poverty

Prevailing measures of relative poverty are unchanged when all incomes grow or contract by the same proportion. This property stems from seemingly implausible assumptions about the disutility of relative deprivation and the cost of social inclusion. The authors propose weakly relative lines that relax these assumptions. On calibrating our measures to national poverty lines and survey data, we find that half the population of the developing world in 2005 lived in poverty, only half of whom were absolutely poor. The total number of poor rose over 1981 to 2005 despite falling numbers of absolutely poor. With sustained economic growth, the incidence of relative poverty became less responsive to further growth. The number of relatively poor rose, just as the numbers of absolutely poor fell.
Effects of Voltage Control in Utility Interactive Dispersed Storage and Generation Systems

When a small generator is connected to the distribution system, the voltage at the point of interconnection is determined largely by the system and not the generator. This paper examines the effect on the generator, on the load voltage and on the distribution system of a number of voltage control strategies. Synchronous generators with three kinds of exciter control are considered, as well as induction generators and constant extinction angle inverters, with and without capacitor compensation. Operation with a constant slightly lagging power factor is shown to have some advantages.
On training with feedback in wideband channels

Transmitter knowledge of channel state has a great impact on wideband fading channel capacity. However, in the low SNR regime, power per dimension does not suffice to provide an accurate measurement of the channel over the entire spectrum. In the presence of feedback, we may collect information at the transmitter about some aspects of the channel quality over a certain portion of the spectrum. In this work, we investigate the effect of such information. We consider channel testing with a finite amount of energy over a block-fading channel in both time and frequency. We consider a transmission scheme in which the wideband channel is decomposed into many parallel narrowband subchannels, each used with a binary modulation scheme. The quality of each subchannel corresponds to the crossover probability of a binary symmetric channel. We use a multi-armed bandit approach to consider the relative costs and benefits of allotting energy for testing versus transmission, and for repeated testing a single subchannel versus testing different subchannels. We give both upper and lower bounds on the number of subchannels that should be probed for throughput maximization under the scheme we have chosen. Our bounds are in terms of available transmission energy, available bandwidth and fading characteristics of the channel. Moreover, in our numerical results, the two bounds are close.
Inertia Effects on the Dynamics of a Disk Levitated by Incompressible Laminar Fluid Flow

This paper develops a nonlinear ordinary differential equation (O.D.E.) of motion for a disk parallel to a flat plate and levitated by incompressible laminar flow of fluid supplied from a central orifice. The fluid's inertia, reflected in high mass flow rates, is accounted for. The transient flow velocity and pressure field are found by iterative integration of the Navier-Stokes equation to determine the O.D.E. for the time-dependent height of the disk (or fluid film thickness). The film thickness is found by not only numerically integrating the O.D.E., but also by linearizing the equation to obtain a closed-form solution. The results of this combined squeeze film, source-flow case compare favorably with experimental data presented which span cases from negligible inertia (viscous dominance) to cases of inertia dominance. Fortunately, the closed-form solution differs only slightly from the numerical solution; this provides relatively accurate expressions for the frequencies and damping coefficients in terms of the geometry, load (or weight of disk), mass flow rate, and the fluid properties.
General Coordinate Transformations as the Origins of Dark Energy

In this note we demonstrate that the algebra associated with coordinate transformations might contain the origins of a scalar field that can behave as an inflaton and/or a source for dark energy. We will call this particular scalar field the diffeomorphism scalar field. In one dimension, the algebra of coordinate transformations is the Virasoro algebra while the algebra of gauge transformations is the Kac–Moody algebra. An interesting representation of these algebras corresponds to certain field theories that have meaning in any dimension. In particular, the so-called Kac–Moody sector corresponds to Yang–Mills theories and the Virasoro sector corresponds to the diffeomorphism field theory that contains the scalar field and a rank-two symmetric, traceless tensor. We will focus on the contributions of the diffeomorphism scalar field to cosmology. We show that this scalar field can, qualitatively, act as a phantom dark energy, an inflaton, a dark matter source, and the cosmological constant Λ.
Physicochemical characterization techniques for solid lipid nanoparticles: principles and limitations

Solid lipid nanoparticles (SLNs) are gaining importance due to numerous advantages they offer as a drug delivery system. SLN incorporate poorly soluble drugs, proteins, biologicals, etc. SLN are prepared by techniques like high-pressure homogenization, sonication and employs a wide range of lipids and surfactants. Physicochemical characterization techniques include particle size analysis, zeta potential and determination of crystallinity/polymorphism. Furthermore, drug loading and drug entrapment efficiency are common parameters used to test the efficiency of SLN. Most importantly, the functionality assay of SLN is essential to predict the activity and performance in vivo. The review presented discusses the importance of SLN in drug delivery with emphasis on principles and limitations associated with their physicochemical characterization.