cssi/SciSciGPT-SciSciNet huggingface dataset:
Development approach for an advanced Orbiting Solar Observatory spacecraft.

sensor filters out the oscillations of the control system and is easy to build and can be made accurate. It can serve to indicate errors of attitude averaged over longer periods. Also, it will be useful to indicate a failure in the attitude control system. However, there is a time delay associated with its indication because of its low frequency response. Therefore it cannot be used as an error sensor for the control system. Sensors above resonance will sense the instantaneous direction of the acceleration vector (represented by the right side of Fig. 5). Such sensors require some damping to eliminate the higher harmonics of the forcing function. Fortunately, most fluids (such as mercury) have sufficient viscosity to provide adequate damping. This sensor will not indicate the correct local vertical as has already been shown. To obtain the vertical, the readings of the sensor have to be corrected according to Eqs. (28) and (33). To compute those corrections one requires the angular accelerations of the satellite in pitch and roll. Figure 6 shows a torsiograph, which can be used to measure the angular acceleration. A flywheel is connected by a shaft to the wall of the satellite. Under angular acceleration the shaft experiences a torque. A shaft in tension has maximum strains in a direction of 45° with respect to its longitudinal direction. These strains are measured by strain A strain gage is made of high-resistance very thin wire mounted between two thin sheets of paper. The wire changes its electrical resistance under strain. In the circuit shown in Fig. 6, there are four strain gages used. They are arranged in a bridge circuit driving a push-pull amplifier. For fast vibrating systems, one could use a d.c. voltage on the strain gages, but for slowly vibrating systems much better results are obtained if a 500 cycle a.c. generator is used to energize the strain gages. This overcomes the problems associated with d.c. amplifiers. The 500-cycle generator can also be used to energize the sensory coils of the bubble level. The direction of the vertical can be computed by Eqs. (28) and (33). This sensor gives instantaneous reading of the local vertical and therefore can be used as the input for an attitude control system if so desired.
Statistics of entrance times

Abstract The statistical properties of the transitions of a discrete Markov process are investigated in terms of entrance times. A simple formula for their density is given and used to measure the synchronization of a process with a periodic driving force. For the McNamara–Wiesenfeld model of stochastic resonance we find parameter regions in which the transition frequency of the process is locked with the frequency of the external driving.
Pseudospectral time‐domain algorithm applied to electromagnetic scattering from electrically large objects

The pseudospectral time-domain (PSTD) algorithm is extended to model the electromagnetic scattering from both 2-D and 3-D objects. The plane-wave excitation and the time-domain near–far field transforms in the stretched coordinates are efficiently incorporated into the scattered-field PSTD algorithm. Numerical results demonstrate the effectiveness of the algorithm in wave-scattering problems. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 123–125, 2001.
Realtime Control of Multiple-focus Phased Array Heating Patterns Based on Noninvasive Ultrasound Thermography

A system for the realtime generation and control of multiple-focus ultrasound phased-array heating patterns is presented. The system employs a 1-MHz, 64-element array and driving electronics capable of fine spatial and temporal control of the heating pattern. The driver is integrated with a realtime 2-D temperature imaging system implemented on a commercial scanner. The coordinates of the temperature control points are defined on B-mode guidance images from the scanner, together with the temperature set points and controller parameters. The temperature at each point is controlled by an independent proportional, integral, and derivative controller that determines the focal intensity at that point. Optimal multiple-focus synthesis is applied to generate the desired heating pattern at the control points. The controller dynamically reallocates the power available among the foci from the shared power supply upon reaching the desired temperature at each control point. Furthermore, anti-windup compensation is implemented at each control point to improve the system dynamics. In vitro experiments in tissue-mimicking phantom demonstrate the robustness of the controllers for short (2-5 s) and longer multiple-focus high-intensity focused ultrasound exposures. Thermocouple measurements in the vicinity of the control points confirm the dynamics of the temperature variations obtained through noninvasive feedback.
The relationship between weather and mortality in ten major metropolitan areas in the united states, 1962–1965

Daily deaths in ten large cities in the United States were correlated with weather elements for the months of January, April, July, and October of the years 1962–1965. In addition to showing the effects of spells of hot, humid weather and pollution episodes (extreme weather), it was determined that large interdiurnal changes of temperature, dewpoint, and pressure were accompanied by fluctuations in daily mortality. This applies to the northcentral and northeastern United States, where increases in mortality were coincident with prefrontal weather, decreases with postfrontal weather. Total mortality was the cause of death which correlated highest with the weather elements. Deaths over age 70, and under 70, follow in that order. There was little essential difference between arteriosclerotic heart disease and stroke in responsiveness to weather events.
On some aspects of the decision to conserve or harvest old growth forest

In recent times, a great deal of concern has been expressed about the decline in the USA's old growth forests. Although there is broad agreement among researchers that old growth forests provide timber and amenity services, and that forest harvesting decisions are inherently stochastic, there have been very few formal analyses that have explicitly accounted for these aspects of the old growth forest management problem. Consequently, this paper studies these aspects of the problem by formulating the decision to conserve or harvest an old growth forest as a Markovian stochastic control problem. It is then shown how this control problem can be analysed numerically using standard linear programming techniques.
Most convex functions are smooth

Abstract In this paper it is shown that differentiability is a generic property of convex functions.
Crystal structures and magnetic properties of CeAu4Si2 and CeAu2Si2

Abstract Single crystals of CeAu 4 Si 2 and CeAu 2 Si 2 have been grown out of ternary fluxes rich in Au, and the former, also by sintering the stoichiometric composition at 750 °C. The single-crystal X-ray refinement result for CeAu 4 Si 2 is orthorhombic, Cmmm (No. 65, Z =2), different from a tetragonal result found from an X-ray powder diffraction refinement [H. Nakashima, et al., J. Alloys Compds. 424 (2006) 7]. For CeAu 2 Si 2 , this is the first report of the stoichiometric crystalline phase, in the known tetragonal I 4/ mmm structure. The anisotropic field- and temperature-dependent magnetizations, as well as specific heat and resistivity data are compared. Although both compounds have related structural packing, they present unique magnetic features. CeAu 2 Si 2 is a typical antiferromagnet with T N =8.8(1) K and CeAu 4 Si 2 features a ferromagnetic component below T c =3.3(1) K. Both phases have effective moments close in value to that of free Ce 3+ .
Survey evidence on producer use and costs of genetically modified seed.

National survey data collected for 1997 in USDA's Agricultural Resource Management Study was used to derive implications and pose hypotheses about the impact on pesticide use, production practices, and producer costs of using genetically modified (GM) seed in soybean and cotton production. Results of the analysis suggest concurrence with scientific and industry claims about the environmental qualities of these technologies. Herbicide treatments on herbicide-resistant acreage were, on average, less than on other acreage, with more of the treatments in post-emergent applications. The mean value of insecticide treatments for target pests on Bt cotton acreage was reduced relative to other acreage with these pest problems. However, mean costs and mean yields on acreage planted in GM seed relative to other acreage did not indicate a cost advantage, or disadvantage, for the GM seed technologies. Additional research is needed to determine whether these suggested relationships hold when critical variables within aggregated groups are tested for their independent influence. [Econolit: Q000, O330] © 2000 John Wiley & Sons, Inc.
Bayesian Randomized Response as a Class Project

This article describes multiple learning opportunities stemming from a classroom project about psychological therapy analyzed through the Bayesian framework. Because the dataset is rather small, students focus naturally on prior elicitation, issues of identifiability and sensitivity analysis. In addition, because there is not a familiar closed form solution, students are forced to apply relevant simulation techniques, including rejection sampling, Metropolis-Hastings algorithm, data augmentation, simulation of Bayes factors, and other model selection criteria. Comparison with surprising frequentist results prompts a reflection of the pros and cons of either approach. Key features for project success (writing skills, feedback) are discussed.
A bayesian methodology for estimating relative permeability curves

Among the various properties important for simulating reservoir behavior, relative permeability curves may be the most poorly determined by current methods. This paper presents a method for obtaining improved estimates of relative permeability curves. A Bayesian-type performance index is used to incorporate prior estimates of relative permeability curves into an automatic history-matching algorithm. Estimates obtained with the method are consistent with the reservoir production and yet conform to the prior estimates.
Boundary effective field theory and trans-Planckian perturbations: astrophysical implications

We contrast two approaches to calculating trans-Planckian corrections to the inflationary perturbation spectrum: the new physics hypersurface (NPH) model, in which modes are normalized when their physical wavelength first exceeds a critical value, and the boundary effective field theory (BEFT) approach, where the initial conditions for all modes are set at the same time, and modified by higher-dimensional operators enumerated via an effective field theory calculation. We show that these two approaches—as currently implemented—lead to radically different expectations for the trans-Planckian corrections to the cosmic microwave background (CMB) and emphasize that in the BEFT formalism we expect the perturbation spectrum to be dominated by quantum gravity corrections for all scales shorter than some critical value. Conversely, in the NPH case the quantum effects only dominate the longest modes that are typically much larger than the present horizon size. Furthermore, the onset of the breakdown in the standard inflationary perturbation calculation predicted by the BEFT formalism is likely to be associated with a feature in the perturbation spectrum, and we discuss the observational signatures of this feature in both CMB and large-scale structure observations. Finally, we discuss possible modifications to both calculational frameworks that would resolve the contradictions identified here.
A Technique for Measuring Electrical Currents in the Solar Corona

A technique is described for measuring electrical currents in the solar corona. It uses radioastronomical polarization measurements of a spatially extended radio source viewed through the corona. The observations yield the difference in the Faraday rotation measure between two closely spaced lines of sight through the corona, a measurement referred to as differential Faraday rotation. It is shown that the expression for differential Faraday rotation is proportional to the path integral nB ds, where n is the plasma density, and B is the coronal magnetic field. The integral is around a closed loop (Amperian loop) in the corona. If the plasma density is assumed roughly constant, the differential Faraday rotation is proportional to the current within the loop, via Ampere's Law. The validity of the constant density approximation is discussed, and two test cases are presented in which the associated error in the inferred current is small, of the order of tens of percent or less. The method is illustrated with observations of the radio source 3C 228 with the Very Large Array (VLA) in 2003 August. A measurement of a differential Faraday rotation "event" on 2003 August 16, yields an estimate of 2.5 × 109 A in the Amperian loop. A smaller event on August 18 yields an enclosed current of 2.3 × 108 A. The implications of these currents for coronal heating are briefly discussed.
The computational complexity of generating random fractals

We examine a number of models that generate random fractals. The models are studied using the tools of computational complexity theory from the perspective of parallel computation. Diffusion-limited aggregation and several widely used algorithms for equilibrating the Ising model are shown to be highly sequential; it is unlikely they can be simulated efficiently in parallel. This is in contrast to Mandelbrot percolation, which can be simulated in constant parallel time. Our research helps shed light on the intrinsic complexity of these models relative to each other and to different growth processes that have been recently studied using complexity theory. In addition, the results may serve as a guide to simulation physics.
Development of molecular electrocatalysts for CO2 reduction and H2 production/oxidation.

The conversion of solar energy to fuels in both natural and artificial photosynthesis requires components for both light-harvesting and catalysis. The light-harvesting component generates the electrochemical potentials required to drive fuel-generating reactions that would otherwise be thermodynamically uphill. This Account focuses on work from our laboratories on developing molecular electrocatalysts for CO2 reduction and for hydrogen production. A true analog of natural photosynthesis will require the ability to capture CO2 from the atmosphere and reduce it to a useful fuel. Work in our laboratories has focused on both aspects of this problem. Organic compounds such as quinones and inorganic metal complexes can serve as redox-active CO2 carriers for concentrating CO2. We have developed catalysts for CO2 reduction to form CO based on a [Pd(triphosphine)(solvent)]2+ platform. Catalytic activity requires the presence of a weakly coordinating solvent molecule that can dissociate during the catalytic cycle a...
Exact Hamiltonian Monte Carlo for Truncated Multivariate Gaussians

We present a Hamiltonian Monte Carlo algorithm to sample from multivariate Gaussian distributions in which the target space is constrained by linear and quadratic inequalities or products thereof. The Hamiltonian equations of motion can be integrated exactly and there are no parameters to tune. The algorithm mixes faster and is more efficient than Gibbs sampling. The runtime depends on the number and shape of the constraints but the algorithm is highly parallelizable. In many cases, we can exploit special structure in the covariance matrices of the untruncated Gaussian to further speed up the runtime. A simple extension of the algorithm permits sampling from distributions whose log-density is piecewise quadratic, as in the “Bayesian Lasso” model.
Ebola Cases and Health System Demand in Liberia

In 2014, a major epidemic of human Ebola virus disease emerged in West Africa, where human-to-human transmission has now been sustained for greater than 12 months. In the summer of 2014, there was great uncertainty about the answers to several key policy questions concerning the path to containment. What is the relative importance of nosocomial transmission compared with community-acquired infection? How much must hospital capacity increase to provide care for the anticipated patient burden? To which interventions will Ebola transmission be most responsive? What must be done to achieve containment? In recent years, epidemic models have been used to guide public health interventions. But, model-based policy relies on high quality causal understanding of transmission, including the availability of appropriate dynamic transmission models and reliable reporting about the sequence of case incidence for model fitting, which were lacking for this epidemic. To investigate the range of potential transmission scenarios, we developed a multi-type branching process model that incorporates key heterogeneities and time-varying parameters to reflect changing human behavior and deliberate interventions in Liberia. Ensembles of this model were evaluated at a set of parameters that were both epidemiologically plausible and capable of reproducing the observed trajectory. Results of this model suggested that epidemic outcome would depend on both hospital capacity and individual behavior. Simulations suggested that if hospital capacity was not increased, then transmission might outpace the rate of isolation and the ability to provide care for the ill, infectious, and dying. Similarly, the model suggested that containment would require individuals to adopt behaviors that increase the rates of case identification and isolation and secure burial of the deceased. As of mid-October, it was unclear that this epidemic would be contained even by 99% hospitalization at the planned hospital capacity. A new version of the model, updated to reflect information collected during October and November 2014, predicts a significantly more constrained set of possible futures. This model suggests that epidemic outcome still depends very heavily on individual behavior. Particularly, if future patient hospitalization rates return to background levels (estimated to be around 70%), then transmission is predicted to remain just below the critical point around Reff = 1. At the higher hospitalization rate of 85%, this model predicts near complete elimination in March to June, 2015.
An Investigation of the Effects of Specialization in Audit Workpaper Review

. This study examines the effect of specialization at the different stages of an audit workpaper review. Auditing literature advises focusing each review level on specific kinds of errors (i.e., seniors on mechanical errors and managers on conceptual errors), rather than having seniors and managers perform successive all-encompassing reviews. However, surveys of review practice suggest that all-encompassing reviews are common. To determine whether specialization at different levels of review improves reviewers' overall effectiveness, this study has 35 managers and 39 seniors actually perform a review of a realistic set of workpapers. Half the subjects performed specialized reviews, whereas the other half performed all-encompassing reviews. Overall accuracy rates in our study are consistent with prior research. In addition, the combined reviews of seniors and managers are more effective than those of either seniors or managers separately, demonstrating the benefits of hierarchical review. However, specialized review leads reviewers to be significantly less accurate than reviewers performing all-encompassing reviews. The results suggest specialization will not automatically improve review effectiveness, and that accounting firms may need to re-evaluate their review guidance and professional training on workpaper reviews.
Primary Graft Dysfunction

Primary graft dysfunction (PGD) is the most important cause of early morbidity and mortality following lung transplantation. PGD affects up to 25% of all lung transplant procedures and currently has no proven preventive therapy. Lung transplant recipients who recover from PGD may have impaired long-term function and an increased risk of bronchiolitis obliterans syndrome. This article aims to provide a state-of-the-art review of PGD epidemiology, outcomes, and risk factors, and to summarize current efforts at biomarker development and novel strategies for prevention and treatment.
Rhythm and Entrainment of Acquisition and Alliance Initiatives and Firm Performance: A Temporal Perspective

A temporal perspective, focusing on when and under what conditions firms should accelerate or slow down their acquisition and alliance initiatives, is gaining momentum in strategy research. We explore the temporal relationships between rhythm, entrainment and firm performance. Firms that temporally structure the rhythm of repetitive acquisitions in an even-event pace achieve superior performance as compared to an even or event pace. We also find that intraentrainment—the internal synchronization between acquisition and alliance initiatives—enhances performance and the extraentrainment of alliances—the synchronization with competitors’ alliance rhythm—enhances performance. Our findings have important implications for the organizational improvisation, dynamic fit and alliance/acquisition experience literatures which further opens the window to understanding the creation of competitive advantage by managing rhythm-type strategic actions over time.
Distributed Estimation Using Reduced-Dimensionality Sensor Observations

We derive linear estimators of stationary random signals based on reduced-dimensionality observations collected at distributed sensors and communicated to a fusion center over wireless links. Dimensionality reduction compresses sensor data to meet low-power and bandwidth constraints, while linearity in compression and estimation are well motivated by the limited computing capabilities wireless sensor networks are envisioned to operate with, and by the desire to estimate random signals from observations with unknown probability density functions. In the absence of fading and fusion center noise (ideal links), we cast this intertwined compression-estimation problem in a canonical correlation analysis framework and derive closed-form mean-square error (MSE) optimal estimators along with coordinate descent suboptimal alternatives that guarantee convergence at least to a stationary point. Likewise, we develop estimators based on reduced-dimensionality sensor observations in the presence of fading and additive noise at the fusion center (nonideal links). Performance analysis and corroborating simulations demonstrate the merits of the novel distributed estimators relative to existing alternatives.
Two-Dimensional Ablation, Thermal Response, and Sizing Program for Pyrolyzing Ablators

The purpose of this paper is to describe and demonstrate new capabilities in the two-dimensional implicit thermal response and ablation program. These expanded capabilities include grid options for flight and arcjet geometries, a sizing algorithm for the flight-type geometry, and an orthotropic thermal conductivity model. Applications to analysis of an orthotropic low-density carbon-phenolic material in arcjet and flight environments relevant to the Orion crew module are presented. For the arcjet environment, multidimensional conduction effects strongly influence the in-depth thermal response. For a lunar return flight environment, in the shoulder region of the crew module (where the radius of curvature is smallest), the thermal response is influenced by multidimensional conduction and by the orientation of the orthotropic material.
Antineutrino astronomy and geophysics

Radioactive decays inside the Earth produce antineutrinos that may be detectable at the surface. Their flux and spectrum contain important geophysical information. New detectors need to be developed, discriminating between sources of antineutrinos, including the cosmic-background. The latter can be related to the frequency of supernovas.
Bisimple monogenic orthodox semigroups

We give a complete description of the structure of all bisimple orthodox semigroups generated by two mutually inverse elements.
The Influence of Same-Sign Cross-Coupled Stiffness on Rotordynamics

The following paper focuses on same-sign stiffness cross coupling from several viewpoints. First, the influence on rotordynamics is analyzed and discussed, followed by a discussion of how past experiments measuring cross-coupled forces on rotating components may have been in error due to an incomplete testing procedure. Finally, experimental tests are presented on a partitioned damper seal and the correct and complete experimental procedure for determining cross-coupled coefficients is described.
Coupled flow, thermal, and structural analysis of aerodynamically heated panels

A finite element approach to coupling flow, thermal and structural analyses of aerodynamically heated panels is presented. The Navier-Stokes equations for laminar compressible flow are solved together with the energy equation and quasi-static structural equations of the panel. Interactions between the flow, panel heat transfer and deformations are studied for thin stainless steel panels aerodynamically heated by Mach 6.6 flow.
Yukawa unification and the superpartner mass scale

Naturalness in supersymmetry (SUSY) is under siege by increasingly stringent LHC constraints, but natural electroweak symmetry breaking still remains the most powerful motivation for superpartner masses within experimental reach. If naturalness is the wrong criterion then what determines the mass scale of the superpartners? We motivate supersymmetry by (1) gauge coupling unification, (2) dark matter, and (3) precision b − τ Yukawa unification. We show that for an LSP that is a bino-Higgsino admixture, these three requirements lead to an upper-bound on the stop and sbottom masses in the several TeV regime because the threshold correction to the bottom mass at the superpartner scale is required to have a particular size. For tan β ≈ 50, which is needed for t−b−τ unification, the stops must be lighter than 2.8 TeV when A t has the opposite sign of the gluino mass, as is favored by renormalization group scaling. For lower values of tan β, the top and bottom squarks must be even lighter. Yukawa unification plus dark matter implies that superpartners are likely in reach of the LHC, after the upgrade to 14 (or 13) TeV, independent of any considerations of naturalness. We present a model-independent, bottom-up analysis of the SUSY parameter space that is simultaneously consistent with Yukawa unification and the hint for m h = 125 GeV. We study the flavor and dark matter phenomenology that accompanies this Yukawa unification. A large portion of the parameter space predicts that the branching fraction for B s → μ + μ − will be observed to be significantly lower than the SM value.
Parallelizing Time with Polynomial Circuits

We study the problem of asymptotically reducing the runtime of serial computations with circuits of polynomial size. We give an algorithmic size-depth tradeoff for parallelizing time t random access Turing machines, a model at least as powerful as logarithmic cost RAMs. Our parallel simulation yields logspace-uniform t O(1) size, O(t/log t)-depth Boolean circuits having semi-unbounded fan-in gates. In fact, for appropriate d, uniform t O(1)2O(t/d) size circuits of depth O(d) can simulate time t. One corollary is that every log-cost time t RAM can be simulated by a log-cost CRCW PRAM using t O(1) processors and O(t/log t) time. This improves over previous parallel speedups, which only guaranteed an Ω(log t)-speedup with an exponential number of processors for weaker models of computation. These results are obtained by generalizing the well-known result that $\textsf{DTIME}[t]\subseteq \textsf{ASPACE}[\log t]$.
Instantons, Euclidean supersymmetry and Wick rotations

Abstract We discuss the reality properties of the fermionic collective coordinates in Euclidean space in an instanton background and construct hermitean actions for N =4 and N =2 supersymmetric Euclidean Yang–Mills theories.
Performance characteristics of a ''damped'' mass expulsion attitude control system.

A new mass expulsion approach to space vehicle attitude control is introduced which shows promise of reducing propellant consumption and pulsing frequency plus providing better acquisition performance (time and propellant) and attitude accuracy than present minimumimpulse controllers. This "damped" attitude control logic is designed to adapt optimally to existing disturbance torques in damping the vehicle's position and rate, thereby driving the vehicle near the minimum propellant expenditure trajectory during each control cycle. Simple adaptive compensation based on the immediate past history of control pulses is included to correct for biased and time-variant disturbance torques, propulsive and sensing errors, and time-variant moments of inertia. The limit-cycle performance of the damped controller is compared with a pseudo-rate and a minimum-impulse controller in the presence of propulsive errors, sensing errors, and external disturbance torques. Results of a threeaxis dynamic simulation indicate that the damped controller uses only one-half of the propellant and only one-fifth of the pulses used by a minimum-impulse controller for a typical low-altitude, elliptical orbit.
Effects of Vaneless Diffuser Geometries on Rotating Stall

Detailed experimental investigation was carried out primarily to document the effects of vaneless diffuser diameter and width ratios on the fundamental characteristics of flow perturbation in the vaneless diffuser of a centrifugal blower. A benchmark set of experimental data is provided to aid numerical investigation of instabilities in the vaneless diffuser flow field in particular and the entire compression system in general. The synchronous speed was also varied to study the effect of shaft speed on stall features. The current data showed that a decrease of the diffuser width, at constant impeller angular speed, resulted in an increase of the critical flow coefficient. The data further revealed that an increase in the diffuser diameter ratio resulted in an increase in the frequency of rotating stall. Unlike diffuser diameter ratio, variation of the diffuser width ratio does not have an appreciable effect on the frequency of rotating stall.
The digestive strategy and efficiency of the West Indian manatee, Trichechus manatus.

Abstract 1. 1. During the winters of 1982/83 and 1983/84, samples of digesta were collected from nine sites along the gastrointestinal tracts of seven West Indian manatees, Trichechus manatus . 2. 2. The voluminous large intestine of the manatee is responsible for considerable water reabsorption, as well as being the major site of organic matter, nitrogen and crude fat digestion. 3. 3. Cellulose digestion occurs primarily in the cecum and anterior portion of the colon in a pattern similar to terrestrial nonruminant herbivores like the horse. 4. 4. Overall digestibility coefficients for organic matter (71%), nitrogen (61%) and crude fat (77%) are comparable to those of terrestrial herbivores. 5. 5. Manatees have one of the highest digestibility coefficients for cellulose (80%) of any known mammalian herbivore. This high efficiency of cellulose digestion is due primarily to an extremely slow rate of passage. In addition, it appears that seagrasses may be more digestible than terrestrial forages, possibly due to their relatively low lignin content.
Do Ordinary Nuclei Contain Exotic States of Matter

The strongly repulsive core of the short-range nucleon-nucleon interaction leads to the existence of high-momentum nucleons in nuclei. Inclusive electron scattering can be used to probe these high-momentum nucleons and study the nature of the corresponding short-range correlations in nuclei. With recent data from Jefferson Lab we have begun to map out the strength of two-nucleon correlations in nuclei, while upcoming experiments should allow us to isolate the presence of multi-nucleon correlations. In addition to their importance in describing nuclear structure, these configurations of correlated nucleons represent high-density ‘droplets’ of hadronic matter. As the density of hadronic matter increases there should be a weakening of quark confinement, similar to the onset of deconfinement expected at extremely high temperatures. While there have been hints of non-hadronic structure in nuclei, future measurements will allow us to directly probe the quark distributions of high-density configurations in nuclei. A modified quark structure in these closely packed nucleons would provide a clear signature of exotic components to the structure of nuclei.
Asset allocation and investment horizon

Abstract Quarterly recommendations by national brokerage firms since the third quarter of 1989 provide an opportunity to compare different approaches to asset allocation. To follow a brokerage firm's recommendation every quarter is to practice tactical asset allocation. Both the length of the investor's decision horizon and brokerage commissions that are incurred when portfolio changes are made impact investment performance, and both contribute to the risk experienced by investors. Buy-and-hold and strategic asset allocation would have served investors better than tactical asset allocation during the first half of the 1990s.
Magnetically Driven Accretion Flows in the Kerr Metric. IV. Dynamical Properties of the Inner Disk

This paper continues the analysis of a set of general relativistic three-dimensional MHD simulations of accreting tori in the Kerr metric with different black hole spins. We focus on bound matter inside the initial pressure maximum, where the time-averaged motion of gas is inward and an accretion disk forms. We use the flows of mass, angular momentum, and energy in order to understand dynamics in this region. The sharp reduction in accretion rate with increasing black hole spin reported in the first paper of this series is explained by a strongly spin-dependent outward flux of angular momentum conveyed electromagnetically; when a/M ≥ 0.9, this flux can be comparable to the inward angular momentum flux carried by the matter. In all cases, there is outward electromagnetic angular momentum flux throughout the flow; in other words, contrary to the assertions of traditional accretion disk theory, there is in general no "stress edge," no surface within which the stress is zero. The retardation of accretion in the inner disk by electromagnetic torques also alters the radial distribution of surface density, an effect that may have consequences for observable properties, such as Compton reflection. The net accreted angular momentum is sufficiently depressed by electromagnetic effects that in the most rapidly spinning black holes mass growth can lead to spin-down. Spinning black holes also lose energy by Poynting flux; this rate is also a strongly increasing function of black hole spin, rising to 10% of the rest-mass accretion rate at very high spin. As the black hole spins faster, the path of the Poynting flux changes from being predominantly within the accretion disk to being predominantly within the funnel outflow.
Distilling clinically interpretable information from data collected on next-generation wearable sensors

Medical electronic systems are generating ever larger data sets from a variety of sensors and devices. Such systems are also being packaged in wearable designs for easy and broad use. The large volume of data and the constraints of low-power, extended-duration, and wireless monitoring impose the need for on-chip processing to distill clinically relevant information from the raw data. The higher-level information, rather than the raw data, is what needs to be transmitted. We present one example of information processing for continuous, high-sampling-rate data collected from wearable and portable devices. A wearable cardiac and motion monitor designed by colleagues at MIT simultaneously records electrocardiogram (ECG) and 3-axis acceleration to onboard memory, in an ambulatory setting. The acceleration data is used to generate a continuous estimate of physical activity. Additionally, we use a Portapres continuous blood pressure monitor to concurrently record the arterial blood pressure (ABP) waveform. To help reduce noise, which is an increased challenge in ambulatory monitoring, we use both the ECG and ABP waveforms to generate a robust measure of heart rate from noisy data. We also generate an overall signal abnormality index to aid in the interpretation of the results. Two important cardiovascular quantities, namely cardiac output (CO) and total peripheral resistance (TPR), are then derived from this data over a sequence of physical activities. CO and TPR can be estimated (to within a scale factor) from heart rate, pulse pressure and mean arterial blood pressure, which in turn are directly obtained from the ECG and ABP signals. Data was collected on 10 healthy subjects. The derived quantities vary in a manner that is consistent with known physiology. Further work remains to correlate these values with the cardiac health state.
THE EFFECT OF ATTENDING THE FLAGSHIP STATE UNIVERSITY ON EARNINGS: A DISCONTINUITY-BASED APPROACH

Abstract This paper examines the effect of attending the flagship state university on the earnings of 28 to 33 year olds by combining confidential admissions records from a large state university with earnings data collected through the state's unemployment insurance program. To distinguish the effect of attending the flagship state university from the effects of confounding factors correlated with the university's admission decision or the applicant's enrollment decision, I exploit a large discontinuity in the probability of enrollment at the admission cutoff. The results indicate that attending the most selective state university causes earnings to be approximately 20% higher for white men.
Unsteady Euler airfoil solutions using unstructured dynamic meshes

Two algorithms for the solution of the time-dependent Euler equations are presented for unsteady aerodynamic analysis of oscillating airfoils. Both algorithms were developed for use on an unstructured grid made up of triangles. The first flow solver involves a Runge-Kutta time-stepping scheme with a finite-volume spatial discretization that reduces to central differencing on a rectangular mesh. The second flow solver involves a modified Euler time-integration scheme with an upwind-biased spatial discretization based on the flux-vector splitting of Van Leer. The paper presents descriptions of the Euler solvers and dynamic mesh algorithm along with results which assess the capability.
Feedback and Weighting Mechanisms for Improving Jacobian Estimates in the Adaptive Simultaneous Perturbation Algorithm

It is known that a stochastic approximation (SA) analogue of the deterministic Newton-Raphson algorithm provides an asymptotically optimal or near-optimal form of stochastic search. However, directly determining the required Jacobian matrix (or Hessian matrix for optimization) has often been difficult or impossible in practice. This paper presents a general adaptive SA algorithm that is based on a simple method for estimating the Jacobian matrix while concurrently estimating the primary parameters of interest. Relative to prior methods for adaptively estimating the Jacobian matrix, the paper introduces two enhancements that generally improve the quality of the estimates for underlying Jacobian (Hessian) matrices, thereby improving the quality of the estimates for the primary parameters of interest. The first enhancement rests on a feedback process that uses previous Jacobian estimates to reduce the error in the current estimate. The second enhancement is based on an optimal weighting of per-iteration Jacobian estimates. From the use of simultaneous perturbations, the algorithm requires only a small number of loss function or gradient measurements per iteration - independent of the problem dimension - to adaptively estimate the Jacobian matrix and parameters of primary interest.
Time-Accurate Euler Simulation of Interaction of Nozzle Wake and Secondary Flow With Rotor Blade in an Axial Turbine Stage Using Nonreflecting Boundary Conditions

The objective of this paper is to investigate the three-dimensional unsteady flow interactions in a turbomachine stage. A three-dimensional time-accurate Euler code has been developed using an explicit four-stage Runge-Kutta scheme. Three-dimensional unsteady nonreflecting boundary conditions are formulated at the inlet and the outlet of the computational domain to remove the spurious numerical reflections. The three-dimensional code is first validated for two-dimensional and three-dimensional cascades with harmonic vortical inlet distortions. The effectiveness of the nonreflecting boundary conditions is demonstrated. The unsteady Euler solver is then used to simulate the propagation of nozzle wake and secondary flow through the rotor and the resulting unsteady pressure field in an axial turbine stage. The three-dimensional and time-dependent propagation of nozzle wakes in the rotor blade row and the effects of nozzle secondary flow on the rotor unsteady surface pressure and passage flow field are studied. It was found that the unsteady flow field in the rotor is highly three dimensional and the nozzle secondary flow has significant contribution to the unsteady pressure on the blade surfaces. Even though the steady flow at the midspan is nearly two dimensional, the unsteady flow is three dimensional and the unsteady pressure distribution cannot be predicted bymore » a two-dimensional analysis.« less
Status of Pep-II and BaBar

In this report, the status of the PEP-II machine and the BaBar detector are presented. Performance is presented as of the Lepton Photon Conference (August 1999) with subsequent performance levels footnoted as appropriate. This report is made on behalf of the SLAC/LBNL/LLNL team that built and commissioned PEP-II, the SLAC Accelerator Department that commissioned and operated the machine, and the 71 institution, 9 nation detector collaboration that built, commissioned, and operate BaBar.
Monte Carlo Analysis of Satellite Beam Pointing Errors

Imperfections in attitude control components and control algorithms of communication s satellites result in spacecraft pointing errors and give rise to a random variation of the radiated power delivered to the ground. Monte Carlo techniques are applied to this statistical problem to obtain design and margin information. A probabilistic method of specifying required power levels is presented.
Synthesis and Evaluation of an α-C-Galactosylceramide Analogue that Induces Th1-biased Responses in Human Natural Killer T Cells

An alpha-galactosylceramide (alphaGalCer, 1) and its isosteric C-glycoside analogue (2) were found to possess promising immunostimulatory activity because of their ability to activate natural killer T (NKT) cells. We report the synthesis of compound 3, a truncated nonisosteric C-alphaGalCer analogue, that like 2 is not enzymatically labile at the glycosidic linkage, but has the anomeric carbon directly bonded to the C1 of the phytoceramide backbone. We compared the biological activity of the three ligands using an in vitro system with human dendritic cells as the antigen-presenting cells and human NKT cells as the responding cells. Although 3 was a less potent agonist for NKT cells than 1 and 2, it induced cytokine production with the highest IFN-gamma:IL-4 and IFN-gamma:IL-13 ratios. Therefore, our data suggest that the new mimetic of alphaGalCer might preferentially promote Th1-immune responses and serve as a potent adjuvant in the immunotherapy of cancer and infectious diseases.
Time-reversal and model-based imaging in a THz waveguide

A substantial improvement in the reconstruction of time-reversed THz fields is demonstrated by adapting a waveguide technique from ultrasound imaging. Furthermore, a model based reconstruction method is considered as an alternative to time-reversal THz imaging.
Taxation and the worlds of welfare

Please note that consumption tax data in the paper are estimated from expenditure data in all cases, and are not directly taken from the LIS. The wording of footnote 6 is misleading, as it suggests that the consumption tax data were obtained from LIS for some countries; this is not the case. This is important to note because our method cannot take into account exemptions of consumption tax for lower-income taxpayers, and will overstate the regressivity of consumption tax in such cases. The authors would like to apologize for this error. We have re-estimated the consumption tax results using the LIS’s v14 category, which is defined as ‘All other types of direct taxes such as consumption tax, church tax, poll tax, etc.’ The conflation of consumption tax with other taxes makes this variable of limited use for our purposes, but does allow some insight. This variable is available for several countries, including three of the countries for which we had estimated sales tax from expenditure (France, Switzerland, and the UK). It proves to be regressive for those three countries, to a similar magnitude as in our paper; and it is regressive for all other countries except Norway. These calculations are available from the authors.
Improved Wind and Turbulence Measurements Using a Low-Cost 3-D Sonic Anemometer at a Low-Wind Site

A year of data from sonic anemometer and mechanical wind sensors was analyzed and compared at a low-wind site. Results indicate that 15-minute average and peak 1-second wind speeds (u) from the sonic agree well with data de- rived from a co-located cup anemometer over a wide range of speeds. Wind direction data derived from the sonic also agree closely with those from a wind vane except for very low wind speeds. Values of standard deviation of longitudinal wind speed (￻ u) and wind direction fluctuations (￻￻) from the sonic and mechanical sensors agree well for times with u > 2 ms -1 but show significant differences with lower u values. The most significant differences are associated with the stan- dard deviation of vertical wind fluctuations (￻ w): the co-located vertical propeller anemometer yields values increasingly less than those measured by the sonic anemometer as u decreases from 2.5 approaching 0 ms -1 . The combination of u over-estimation and under-estimation of ￻ w from the mechanical sensors at low wind speeds causes considerable under- estimation of the standard deviation of vertical wind angle fluctuations (￻￻), an indicator of vertical dispersion. Calcula- tions of ￻￻ from sonic anemometer measurements are typically 5° to 10° greater than from the mechanical sensors when the mechanical instruments indicate that ￻￻ < 5° or so. The errors with the propeller anemometer, cup anemometer and wind vane, caused by their inability to respond to higher frequency (smaller scale) turbulent fluctuations, can therefore lead to large (factors of 2 to 10 or more) errors in both the vertical and horizontal dispersion during stable conditions with light winds. The sonic anemometer clearly provides more accurate and reliable wind data than the mechanical wind sensor with u < 2.5 ms -1 .
Calix[4]pyrrole-Based Ion Pair Receptors

ConspectusIon pair receptors, which are able to bind concurrently both a cation and an anion, often display higher selectivity and affinity for specific ion pairs than simple ion receptors capable of recognizing primarily either a cation or an anion. This enhancement in recognition function is attributable to direct or indirect cooperative interactions between cobound ions via electrostatic attractions between oppositely charged ions, as well as to positive allosteric effects. In addition, by virtue of binding the counterions of the targeted ion, ion pair receptors can minimize the solvation of the counterions, which can otherwise have a negative effect on the interactions between the receptors and the targeted ions. As a result of their more favorable interactions, ion pair receptors are attractive for use in applications, such as extraction and sensing, where control of the binding interactions is advantageous. In this Account, we illustrate this potential in the context of ion pair receptors based on t...