cssi/SciSciGPT-SciSciNet huggingface dataset:
Model Uncertainty and the Management of a System of Infrastructure Facilities

The network-level infrastructure management problem involves selecting and scheduling maintenance, repair, and rehabilitation (MR&R) activities on networks of infrastructure facilities so as to maintain the level of service provided by the network in a cost-effective manner. This problem is frequently formulated as a Markov decision problem (MDP) solved via linear programming (LP). The conditions of facilities are represented by elements of discrete condition rating sets, and transition probabilities are employed to describe deterioration processes. Epistemic and parametric uncertainties not considered within the standard MDP/LP framework are associated with the transition probabilities used in infrastructure management optimization routines. This paper contrasts the expected costs incurred when model uncertainty is ignored with those incurred when this uncertainty is explicitly considered using robust optimization. A case study involving a network-level pavement management MDP/LP problem demonstrates how explicitly considering uncertainty may limit worst-case MR&R expenditures. The methods and results can also be used to identify the costs of uncertainty in transition probability matrices used in infrastructure management systems.
Hiding in Plain Sight: Timing and Transparency in the Administrative State

Anecdotal evidence of agencies burying bad news is rife in law and politics. The bureaucracy regularly is accused of announcing controversial policies on holidays and weekends when public attention is elsewhere. We show that this conventional wisdom is wrong, or at least significantly incomplete. The conventional wisdom is riddled with theoretical holes, and there is little systematic empirical evidence to support it. After critiquing the conventional account of agencies hiding bad news, we articulate and defend a revised theory of strategic timing in administrative law. We argue that timing decisions rarely affect the visibility of decisions but can drive up the costs of monitoring and responding for interest groups and legislative coalitions. Agency discretion to choose when to announce policy decisions can even allow agencies to influence which interest groups monitor the regulatory process and therefore whose preferences must be taken into account. We evaluate both the conventional wisdom and our revised theory using twenty-five years of empirical evidence. We then develop the implications for administrative law doctrine and institutional design of the bureaucracy.
Model‐based, sensor‐directed remediation of underground storage tanks

Sensor-rich, intelligent robots that function with respect to models of their environment have significant potential to reduce the time and cost for the cleanup of hazardous waste while increasing operator safety. Sandia National Laboratories is performing experimental investigations into the application of intelligent robot control technology to the problem of removing waste stored in tanks. This article describes the experimental environment employed at Sandia with particular attention to the computing and software control environment. Intelligent system control is achieved through the integration of extensive geometric and kinematic world models with real-time sensor-based control. All operator interactions with the system are through fully animated, graphical representations that validate all operator commands before execution to provide for safe operation. Sensing is used to add information to the robot system's world model and to allow sensor-based servo control during selected operations. The results of a first critical features test are reported and the potential for applying advanced intelligent control concepts to the removal of waste in storage tanks is discussed.
Strain-tunable topological quantum phase transition in buckled honeycomb lattices

Low-buckled silicene is a prototypical quantum spin Hall insulator with the topological quantum phase transition controlled by an out-of-plane electric field. We show that this field-induced electronic transition can be further tuned by an in-plane biaxial strain e, owing to the curvature-dependent spin-orbit coupling (SOC): There is a Z2 = 1 topological insulator phase for biaxial strain |e| smaller than 0.07, and the band gap can be tuned from 0.7 meV for e=+0.07 up to 3.0 meV for e=−0.07. First-principles calculations also show that the critical field strength Ec can be tuned by more than 113%, with the absolute values nearly 10 times stronger than the theoretical predictions based on a tight-binding model. The buckling structure of the honeycomb lattice thus enhances the tunability of both the quantum phase transition and the SOC-induced band gap, which are crucial for the design of topological field-effect transistors based on two-dimensional materials.
Testing for Racial Prejudice in the Parole Board Release Process: Theory and Evidence

We develop a model of a Parole Board contemplating whether to grant parole release to a prisoner who has nished serving their minimum sentence. The model implies a simple outcome test for racial prejudice which is based on the released inmate’s rate of recidivism and is robust to the inframarginality problem. Our model has several testable implications which we show empirical support for. Applying our test to data on all prison releases in Pennsylvania between 1999-2003 we nd no evidence of racial prejudice.
Unbiased bits from sources of weak randomness and probabilistic communication complexity

A new model for weak random physical sources is presented. The new model strictly generalizes previous models (e.g., the Santha and Vazirani model [27]). The sources considered output strings according to probability distributions in which no single string is too probable.The new model provides a fruitful viewpoint on problems studied previously such as: • Extracting almost-perfect bits from sources of weak randomness. The question of possibility as well as the question of efficiency of such extraction schemes are addressed. • Probabilistic communication complexity. It is shown that most functions have linear communication complexity in a very strong probabilistic sense. • Robustness of BPP with respect to sources of weak randomness (generalizing a result of Vazirani and Vazirani [32], [33]).
Assessment and management of comorbidities (including cardiovascular disease) in patients with nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of liver disease worldwide. Nonalcoholic steatohepatitis, the progressive form of NAFLD, can lead to end-stage liver disease and hepatocellular carcinoma. However, the consequences of NAFLD are not confined to the liver. NAFLD is associated with an increased risk of cardiovascular disease (CVD) and is frequently associated with metabolic syndrome. Thus, there is a pressing need for the diagnosis and management of the comorbidities of NAFLD, including CVD. This review will guide clinicians in the assessment and management of metabolic disease and CVD in patients with NAFLD.
Relationship Between Liver Function and Brain Shrinkage in Patients with Alcohol Dependence

’Background: Oxidative stress has been proposed as one of the mechanisms of alcohol-induced brain shrinkage and alcohol-induced hepatotoxicity. The aim of this study was to assess the correlations between liver function and brain volume (BV) measurements in patients with alcohol dependence. Methods: We recruited 124 patients with alcohol dependence and 111 healthy control subjects from National Institute of Health, National Institute on Alcohol Abuse and Alcoholism inpatient alcohol treatment program. Gamma-glutamyl transferase (GGT), aspartate aminotransferase (AST), alanine aminotransferase (ALT), as well as hematocrit (Hct) and albumin were assayed shortly after admission. Magnetic resonance imaging examination was conducted in both groups (after 3-week abstinence in the patient group). We used stepwise linear regression analyses to determine the variables most strongly correlated with brain shrinkage. Results: Patients with alcohol dependence had lower BV, and greater brain shrinkage as measured by gray matter ratio (GMR), white matter ratio (WMR), brain ratio (BR), and higher cerebrospinal fluid ratio ratio (CSFR) compared with their healthy counterparts. Age and sex were significantly correlated with some BV measurements in both patient and control groups. Body mass index (BMI) was significantly correlated with CSFR, BR, GMR, and WMR; Hct with CSFR and BR; serum GGT level with BV, CSFR, BR, GMR, and WMF in the patient group. No biological variables were correlated with BV indices in the control group. In gender-stratified analysis, age was significantly correlated with brain shrinkage in male patients but not in female patients. Serum GGT level in male and female patients, Hct in male patients, and AST levels in female patients were significantly correlated with brain shrinkage. Conclusions: Our results showed that the higher levels of liver function indices, especially GGT, correlated with BV shrinkage as measured using CSFR, BR, GMR, and WMR in patients with alcohol dependence but not in controls. Serum GGT level outweighed aging effect on brain
Deconvolution of linear systems by constrained regression and its relationship to the Wiener theory

In this paper we discuss the problem of deconvolution of the output of a linear system in the presence of noise, and a previously known technique for solving integral equations is applied. It is shown how this solution is equivalent to constrained linear regression and that this may be computed in the frequency domain. Finally, the relationship between deconvolution by constrained linear regression and by Wiener theory is derived, and it is shown that the constrained regression technique requires far less a priori knowledge than does the Wiener theory.
An economist's perspective on multi-agent learning

We comment on the Shoham, Powers, and Grenager survey of multi-agent learning and game theory, emphasizing that some of their categories are important for economics and others are not. We also try to correct some minor imprecisions in their discussion of the economics literature on learning in games.
Sigma-delta modulator with spectrally shaped feedback

This paper explores the use of finite-impulse response (FIR) filters in the feedback path of a low-pass sigma-delta modulator in order to combat some nonideal effects encountered in an analog implementation. In this approach, the filter corresponding to the first integrator is a lowpass filter which smoothes out the feedback waveform by attenuating the high-frequency quantization noise. This lowpass filtering decreases the power consumption of a switched-capacitor implementation and alternatively reduces the sensitivity to clock jitter in a continuous-time structure. A design methodology ensuring the stability of the system is presented. Theoretical analysis and simulations show that the FIR filters allow a continuous-time single-bit modulator to achieve the jitter performance of a comparable multibit modulator.
Synthesis and anticancer activity of epipolythiodiketopiperazine alkaloids

The epipolythiodiketopiperazine (ETP) alkaloids are a highly complex class of natural products with potent anticancer activity. Herein, we report the application of a flexible and scalable synthesis, allowing the construction of dozens of ETP derivatives. The evaluation of these compounds against cancer cell lines in culture allows for the first expansive structure–activity relationship (SAR) to be defined for monomeric and dimeric ETP-containing natural products and their synthetic cognates. Many ETP derivatives demonstrate potent anticancer activity across a broad range of cancer cell lines and kill cancer cells via induction of apoptosis. Several traits that bode well for the translational potential of the ETP class of natural products include concise and efficient synthetic access, potent induction of apoptotic cell death, activity against a wide range of cancer types, and a broad tolerance for modifications at multiple sites that should facilitate small-molecule drug development, mechanistic studies, and evaluation in vivo.
Multi-Terrain Earth Landing Systems Applicable for Manned Space Capsules

A key element of the President's Vision for Space Exploration is the development of a new space transportation system to replace Shuttle that will enable manned exploration of the moon, Mars, and beyond. NASA has tasked the Constellation Program with the development of this architecture, which includes the Ares launch vehicle and Orion manned spacecraft. The Orion spacecraft must carry six astronauts and its primary structure should be reusable, if practical. These requirements led the Constellation Program to consider a baseline land landing on return to earth. To assess the landing system options for Orion, a review of current operational parachute landing systems such as those used for the F-111 escape module and the Soyuz is performed. In particular, landing systems with airbags and retrorockets that would enable reusability of the Orion capsule are investigated. In addition, Apollo tests and analyses conducted in the 1960's for both water and land landings are reviewed. Finally, tests and dynamic finite element simulations to understand land landings for the Orion spacecraft are also presented.
Economic Indicators for the US Transportation Sector

Since the transportation sector plays an important role in business cycle propagation, we develop indicators for this sector to identify its current state, and predict its future. We define the reference cycle, including both business and growth cycles, for this sector over the period from 1979 using both the conventional National Bureau of Economic Research (NBER) method and modern time series models. A one-to-one correspondence between cycles in the transportation sector and those in the aggregate economy is found; however, both business and growth cycles of transportation often start earlier and end later than those of the overall economy. We also construct an index of leading indicators for the transportation sector using rigorous statistical procedures, and is found to perform well as a forecasting tool.
Did Iraq Cheat the United Nations? Underpricing, Bribes, and the Oil for Food Program

From 1997 through 2003, the UN Oil for Food Program allowed Iraq to export oil for humanitarian supplies. We hypothesize that Iraq deliberately set the price of its oil below market prices to solicit bribes from oil buyers. By comparing the price gap between Iraqi oil and its close substitutes during the Program to the gap prior to the Program, we nd evidence of signican t underpricing. Our central estimate suggests that Iraq collected $1.3 billion in bribes from underpricing its oil, or 2 percent of oil revenues. Underpricing is higher during periods of high volatility in oil markets{when detection is more dicult{but declines after the UN limited Iraq's ability to set the price of its oil.
The development of the external form of the guinea‐pig (cavia cobaya) between the ages of 21 days and 35 days of gestation

The authors are preparing a table for the normal developments of the guinea-pig. This paper deals with the external form and the development of the external characteristics of guinea-pigs between 21 days and 35 days, copulation age. About one hundred embryos were used from thirty-six litters. Length and weight are good criteria for determining age, although there is some variation. The flexures, the disappearance of the tail, the development of hair follicles at specific locations, the degree of development of the mouth and external ear are better criteria for the determination of age. At 27 days there is a sudden increase in both weight and length. This increase is rather uniform from this period until the end of 35 days. At this time the embryo has the appearance of a newborn guinea-pig.
Education and Training Needs in the Radiation Sciences: Problems and Potential Solutions

This article provides a summary of presentations focused on critical education and training issues in radiation oncology, radiobiology and medical physics from a workshop conducted as part of the 60th Annual Meeting of the Radiation Research Society held in Las Vegas, NV (September 21–24, 2014). Also included in this synopsis are pertinent comments and concerns raised by audience members, as well as recommendations for addressing ongoing and future challenges.
Preisach modeling of piezoceramic and shape memory alloy hysteresis

Smart materials such as piezoceramics, magnetostrictive materials, and shape memory alloys exhibit hysteresis, and the larger the input signal the larger the effect. Hysteresis can lead to unwanted harmonics, inaccuracy in open loop control, and instability in closed loop control. The Preisach independent domain hysteresis model has been shown to capture the major features of hysteresis arising in ferromagnetic materials. Noting the similarity between the microscopic domain kinematics that generate static hysteresis effects in ferromagnetics, piezoceramics, and shape memory alloys (SMAs), we apply the Preisach model for the hysteresis in piezoceramic and shape memory alloy materials. This paper reviews the basic properties of the Preisach model, discusses control-theoretic issues such as identification, simulation, and inversion, and presents experimental results for piezoceramic sheet actuators bonded to a flexible aluminum beam, and a Nitinol SMA wire muscle that applies a bending force to the end of a beam.
The limits of direct satellite tracking with GPS

The expected accuracy of the direct user orbit solution and the magnitude of the principal error sources are evaluated using the techniques of covariance analysis. Utilization of advanced GPS receivers, measurement calibration methods, and geophysical models developed for high-precision GPS-based geodesy and differential satellite tracking are assumed in order to explore the limiting accuracy of the above technique. In addition, the dependence of user orbit accuracy on such factors as data arc length, the time interval between the end of the ground data arc used for GPS orbit solutions and the beginning of the user data arc, and data types used are studied. For comparison, results from the analysis of a full differential orbit solution are also presented. It is shown that submeter real-time accuracy can be readily achieved for a user above 700 km altitude, even when the user solution is based on a GPS ephemeris that is more than 12 h old.
Enabling Enhanced Emission and Low Threshold Lasing of Organic Molecules Using Special Fano Resonances of Macroscopic Photonic Crystals

We present a novel optofluidic platform comprising organic molecules in solution suspended on photonic crystal slabs. Through macroscopic Fano resonances provided, enhanced spontaneous emission and low-threshold lasing of organic molecules were observed and theoretically analyzed.
Interleukin-Driven Insulin-Like Growth Factor Promotes Prostatic Inflammatory Hyperplasia

Prostatic inflammation is of considerable importance to urologic research because of its association with benign prostatic hyperplasia and prostate cancer. However, the mechanisms by which inflammation leads to proliferation and growth remain obscure. Here, we show that insulin-like growth factors (IGFs), previously known as critical developmental growth factors during prostate organogenesis, are induced by inflammation as part of the proliferative recovery to inflammation. Using genetic models and in vivo IGF receptor blockade, we demonstrate that the hyperplastic response to inflammation depends on interleukin-1–driven IGF signaling. We show that human prostatic hyperplasia is associated with IGF pathway activation specifically localized to foci of inflammation. This demonstrates that mechanisms of inflammation-induced epithelial proliferation and hyperplasia involve the induction of developmental growth factors, further establishing a link between inflammatory and developmental signals and providing a mechanistic basis for the management of proliferative diseases by IGF pathway modulation.
Economic Performance of U.S. Multinational Agribusinesses: Foreign Direct Investment and Firm Strategy

This study borrows the theoretical framework developed by Lee and Habte-Giorgis (2004) to empirically assess the sequential relationships between firm strategic factors, foreign direct investment (FDI) activity, and financial performance for a sample of U.S.-based multinational agribusinesses. After using hierarchical regressions and path analysis, this study finds a positive direct effect of FDI on performance, a complementary effect between FDI and firm strategic factors (positive and significant interaction terms) on performance, and a positive effect of FDI on performance given a threshold for firm size. Specifically, it provides insights about the direct effect of FDI on performance, as well as about the joint effect of firm size and FDI, marketing intensity and FDI, and capital intensity and FDI on performance. These findings provide evidence that FDI activity is an important factor for U.S. agribusiness financial strength. [JEL classifications: F230, Q130, L250].
THE DOMINANCE OF NEUTRINO-DRIVEN CONVECTION IN CORE-COLLAPSE SUPERNOVAE

Multi-dimensional instabilities have become an important ingredient in core-collapse supernova (CCSN) theory. Therefore, it is necessary to understand the drivin g mechanism of the dominant instability. We compare our parameterized three-dimensional CCSN simulations with other buoyancy-driven simulations and propose scaling relations for neutrino-driven convection. Throug h these comparisons, we infer that buoyancy-driven convection dominates post-shock turbulence in our simulations. In support of this inference, we present four major results. First, the convective fluxes and kinetic ener gies in the neutrino-heated region are consistent with expectations of buoyancy-driven convection. Second, the convective flux is positive where buoyancy actively drives convection, and the radial and tangential components of the kinetic energy are in rough equipartition (i.e. Kr ∼ K� + K�). Both results are natural consequences of buoyancy-drive n convection, and are commonly observed in simulations of convection. Third, buoyant driving is balanced by turbulent dissipation. Fourth, the convective luminosity and turbulent dissipation scale wit h the driving neutrino power. In all, these four results suggest that in neutrino-driven explosions, the multi-dim ensional motions are consistent with neutrino-driven convection. Subject headings:convection — hydrodynamics — instabilities — methods:analytical — methods: numerical — shock waves — supernovae: general — turbulence
What Determines Productivity

Economists have shown that large and persistent differences in productivity levels across businesses are ubiquitous. This finding has shaped research agendas in a number of fields, including (but not limited to) macroeconomics, industrial organization, labor, and trade. This paper surveys and evaluates recent empirical work addressing the question of why businesses differ in their measured productivity levels. The causes are manifold, and differ depending on the particular setting. They include elements sourced in production practices -- and therefore over which producers have some direct control, at least in theory -- as well as from producers' external operating environments. After evaluating the current state of knowledge, I lay out what I see are the major questions that research in the area should address going forward. (JEL D24, G31, L11, M10, O30, O47)
Experimental Measurements of the Flow and Heat Transfer of a Square Jet Impinging on an Array of Square Pin Fins

An experimental investigation was conducted to explore the flow behavior, pressure drop, and heat transfer due to free air jet impingement on square inline pin fin heat sinks (PFHS) mounted on a plane horizontal surface. A parametrically consistent set of aluminum heat sinks with fixed base dimension of 25 x 25 mm was used, with pin heights varying between 12.5 mm and 22.5 mm, and fin thickness between 1.5 mm and 2.5 mm. A 6:1 contracting nozzle having a square outlet cross sectional area of 25 x 25 mm was used to blow air at ambient temperature on the top of the heat sinks with velocities varying from 2 to 20 m/s. The ratio of the gap between the jet exit and the pin tips to the pin height, the so-called tip clearance ratio, was varied from 0 (no tip clearance) to 1. The stagnation pressure recovered at the center of the heat sink was higher for tall pins than short pins. The pressure loss coefficient showed a little dependence on Re, increased with increasing pin density, and pin diameter, and decreased with increasing pin height and clearance ratio. The overall base-to-ambient thermal resistance decreased with increasing Re number, pin density and pin diameter. Surprisingly, the dependence of the thermal resistance on the pin height and clearance ratio was shown to be mild at low Re, and to vanish at high Re number.
Vaulted Biaryls in Catalysis: A Structure–Activity Relationship Guided Tour of the Immanent Domain of the VANOL Ligand

The active site in the BOROX catalyst is a chiral polyborate anion (boroxinate) that is assembled in situ from three equivalents of BA3 and one of the VANOL ligand by a molecule of substrate. The substrates are bound to the boroxinate by H bonds to oxygen atoms O1-O3. The effects of introducing substituents at each position of the naphthalene core of the VANOL ligand are systematical- ly investigated in an aziridination reac- tion. Substituents in the 4,4'- and 8,8'- positions have a negative effect on cat- alyst performance, whereas, substitu- ents in the 7- and 7'-positions have the biggest impact in a positive direction.
Navier-Stokes Computations of Limit-Cycle Oscillations for a B-1-Like Configuration

A nonlinear aeroelastic analysis method that solves for the Navier-Stokes equations is put to test in an attempt to capture a limit-cycle oscillation (LCO) phenomenon that is characterized by a coupling of aerodynamic forces due to vortical flow with the elastic response of a wing structure. Time-accurate solutions are computed for unsteady, transonic (M∞ = 0.975), and viscous (Re c = 5.9 x 10 6 ) flows over a B-1-like wing-body configuration at angles of attack of 7.38, 7.88, 8.00, 8.13, 8.25, and 8.38 deg. All flowfield solutions are obtained with the CFL3D Euler/Navier-Stokes solver that was extensively modified for strongly coupled nonlinear aeroelastic analyses. Phase diagrams and aerodynamic damping estimates are used to identify LCO. The predicted aerodynamic damping appears to capture the trends of the experimental data. There is a good correlation between experimental oilflow images and computed instantaneous streamline patterns. The computed amplitude of the wing structural response is much smaller than indicated by flight and wind-tunnel tests. The choice of the computational time step size is identified as a major factor in modeling the development of LCO.
Scaling trends of on-chip power distribution noise

The design of power distribution networks in high-performance integrated circuits has become significantly more challenging with recent advances in process technologies. As on-chip currents exceed tens of amperes and circuit clock periods are reduced well below a nanosecond, the signal integrity of on-chip power supply has become a primary concern in the integrated circuit design. The scaling behavior of the inductive and resistance voltage drops across the on-chip power distribution networks is the subject of this paper. The existing work on power distribution noise scaling is reviewed and extended to include the scaling behavior of the inductance of the on-chip global power distribution networks in high-performance flip-chip packaged integrated circuits. As the dimensions of the on-chip devices are scaled by S, where S>1, the resistive voltage drop across the power grids remains constant and the inductive voltage drop increases by S, if the metal thickness is maintained constant. Consequently, the signal-to-noise ratio decreases by S in the case of resistive noise and by S/sup 2/ in the case of inductive noise. As compared to the constant metal thickness scenario, ideal interconnect scaling of the global power grid mitigates the unfavorable scaling of the inductive noise but exacerbates the scaling of resistive noise by a factor of S. On-chip inductive noise will, therefore, become of greater significance with technology scaling. Careful tradeoffs between the resistance and inductance of the power distribution networks will be necessary in nanometer technologies to achieve minimum power supply noise.
Convergent Validity of Revealed and Stated Recreation Behavior with Quality Change: A Comparison of Multiple and Single Site Demands

We consider the convergent validity of several demand models using beach recreation data. Two models employ multiple site data: a count data demand system model and the Kuhn–Tucker demand system model. We explore the role of existing variation in beach width in explaining trip choices, and analyze a hypothetical 100 foot increase in beach width. We compare these models to a single equation model where we jointly estimate revealed and stated preference trip data, and focus on a hypothetical scenario considering a 100 foot increase in beach width. In each case we develop estimates of the change in beach visits and the welfare impacts from the increase in width. The trip change estimates from two of the three models are similar and convergent valid, though the willingness to pay estimates differ in magnitude.
Tidal alignments as a contaminant of redshift space distortions

We investigate the effect of orientation-dependent selection effects on galaxy clustering in redshift space. It is found that if galaxies are aligned by large-scale tidal fields, then these selection effects give rise to a dependence of the observed galaxy density on the local tidal field, in addition to the well-known dependences on the matter density and radial velocity gradient. This alters the galaxy power spectrum in a way that is different for Fourier modes parallel to and perpendicular to the line of sight. These tidal galaxy alignments can thus mimic redshift space distortions (RSD), and thus result in a bias in the measurement of the velocity power spectrum. If galaxy orientations are affected only by the local tidal field, then the tidal alignment effect has exactly the same scale and angular dependence as the RSDs in the linear regime, so it cannot be projected out or removed by masking small scales in the analysis. We consider several toy models of tidal alignments and orientation-dependent selection, normalize their free parameter (an amplitude) to recent observations, and find that they could bias the velocity amplitude f(z)G(z) by 5–10 per cent in some models, although most models give much smaller contamination. We conclude that tidal alignments may be a significant systematic error in RSD measurements that aim to test general relativity via the growth of large-scale structure. We briefly discuss possible mitigation strategies.
Design of a pulsed switching magnet for the Bevalac

The design and construction of a water-cooled, pulsed, laminated core dipole magnet recently installed at the Bevalac are described. The magnet has been specifically designed for maximum efficiency in power utilization and has replaced two DC powered magnets in the Bevalac switchyard. It will reduce energy usage by 747 MWh/yr, and it provides the capability of pulse-to-pulse switching in 0.7 s between two major beamline channels serving the nuclear science and radiotherapy programs at the Bevalac. A unique feature of this magnet is the core design, which utilizes an external structure that remains integral with the core laminations after assembly. The structure provides for both torsional and longitudinal rigidity of the core while also facilitating the precision assembly and compression of the core laminations without the use of special assembly fixtures. >
Education and Borrowing Constraints: Tests vs. Prices

This paper examines the properties of exams and markets as alternative allocation devices under borrowing constraints. Exams dominate markets in terms of matching efficiency. Whether aggregate consumption is greater under exams than under markets depends on the power of the exam technology; for a sufficiently powerful test, exams dominate markets in terms of aggregate consumption as well. The positive effects of income taxation are analyzed and the optimal allocation scheme when wealth is observable is derived. The latter consists of a fellowship scheme in which markets set school prices but the government gives out fellowships based on need and the ability to obtain a given exam score.
Mid-Infrared Imaging of a Circumstellar Disk around HR 4796: Mapping the Debris of Planetary Formation

We report the discovery of a circumstellar disk around the young AO star, HR 4796, in thermal infrared imaging carried out at the W.M. Keck Observatory.
Generalized Optimal Feedback Controllers for Discrete-Time Linear Systems

This paper presents a unified treatment to the problem of optimal feedback control of discrete-time linear constant parameter systems using state feedback, output feedback, dynamical output feedback and observer-controller feedback. A class of generalized optimal feedback controllers is proposed as a basis for obtaining existing results as well as for deriving new results such as the interesting min-max feedback controllers. The essence of the generalized results lies in the minimization of a class of generalized performance measures subject to a flexible controller configuration. The stability aspect of the generalized optimal feedback controlled system is addressed.
Enantioselective Intermolecular [2 + 2 + 2] Cycloadditions of Ene–Allenes with Allenoates

An enantioselective [2 + 2 + 2] cycloaddition of ene-allenes with allenoates is described, which transforms simple π-components into stereochemically complex carbocycles in a single step. The rhodium(I)-catalyzed cycloaddition proceeds with good levels of enantioselectivity, and with high levels of regio-, chemo-, and diastereoselectivity. Our results are consistent with a mechanism involving an enantioselective intermolecular allene-allene oxidative coupling.
Asymptotic Tracking for Systems With Structured and Unstructured Uncertainties

The control of systems with uncertain nonlinear dynamics has been a decades-long mainstream area of focus. The general trend for previous control strategies developed for uncertain nonlinear systems is that the more unstructured the system uncertainty, the more control effort (i.e., high gain or high-frequency feedback) is required to cope with the uncertainty, and the resulting stability and performance of the system is diminished (e.g., uniformly ultimately bounded stability). This brief illustrates how the amalgamation of an adaptive model-based feedforward term (for linearly parameterized uncertainty) with a robust integral of the sign of the error (RISE) feedback term (for additive bounded disturbances) can be used to yield an asymptotic tracking result for Euler-Lagrange systems that have mixed unstructured and structured uncertainty. Experimental results are provided that illustrate a reduced root-mean-squared tracking error with reduced control effort.
Next generation photonic network elements -multigranularity switching and rate flexible transponders

This paper presents advanced network elements that achieve extremely high capacity and bandwidth flexibility in next-generation photonic networks. Multi-granularity-switching nodes and bit-rate-flexible transponders are discussed with experimental results including 10-Tbit/s-throughput switching and 10-Gbit/s-to-100-Gbit/s bit-rate flexibility.
Listening to Advice: Assessing the External Impact of IMF Article IV Consultations of the United States, 2010–2011

Since 1997, the International Monetary Fund's (IMF) role in surveillance of member countries has changed dramatically. Surveillance, as mandated in Article IV of the Articles of Agreement, has moved from a private process to a public one, with documentation from the consultation freely available at the Fund's Website. But does this public process of surveillance make a difference in generating policy debates? To answer this question, we evaluate whether the Fund's Article IV review was referenced on Capitol Hill and by the White House during two consecutive reviews in the summers of 2010 and 2011. Given the debate about the debt ceiling, the summer of 2011 is a most likely case for the Fund's advice to enter into the policy process. There is little evidence that findings from these reports percolated into the public sphere, casting doubt on the effectiveness of IMF surveillance in developed countries.
Porphyrins bearing arylphosphonic acid tethers for attachment to oxide surfaces.

Synthetic molecules bearing phosphonic acid groups can be readily attached to oxide surfaces. As part of a program in molecular-based information storage, we have developed routes for the synthesis of diverse porphyrinic compounds bearing phenylphosphonic acid tethers. The routes enable (1) incorporation of masked phosphonic acid groups in precursors for use in the rational synthesis of porphyrinic compounds and (2) derivatization of porphyrins with masked phosphonic acid groups. The precursors include dipyrromethanes, monoacyldipyrromethanes, and diacyldipyrromethanes. The tert-butyl group has been used to mask the dihydroxyphosphoryl substituent. The di-tert-butyloxyphosphoryl unit is stable to the range of conditions employed in syntheses of porphyrins and multiporphyrin arrays yet can be deprotected under mild conditions (TMS-Cl/TEA or TMS-Br/TEA in refluxing CHCl3) that do not cause demetalation of zinc or magnesium porphyrins. The porphyrinic compounds that have been prepared include (1) A3B-, trans...
Image Sharing Technologies and Reduction of Imaging Utilization: A Systematic Review and Meta-analysis

Abstract Introduction Image sharing technologies may reduce unneeded imaging by improving provider access to imaging information. A systematic review and meta-analysis were conducted to summarize the impact of image sharing technologies on patient imaging utilization. Methods Quantitative evaluations of the effects of PACS, regional image exchange networks, interoperable electronic heath records, tools for importing physical media, and health information exchange systems on utilization were identified through a systematic review of the published and gray English-language literature (2004-2014). Outcomes, standard effect sizes (ESs), settings, technology, populations, and risk of bias were abstracted from each study. The impact of image sharing technologies was summarized with random-effects meta-analysis and meta-regression models. Results A total of 17 articles were included in the review, with a total of 42 different studies. Image sharing technology was associated with a significant decrease in repeat imaging (pooled effect size [ES] = –0.17; 95% confidence interval [CI] = [–0.25, –0.09]; P P = .002). For all outcomes combined, image sharing technology was not associated with utilization. Most studies were at risk for bias. Conclusions Image sharing technology was associated with reductions in repeat and unnecessary imaging, in both the overall literature and the most-rigorous studies. Stronger evidence is needed to further explore the role of specific technologies and their potential impact on various modalities, patient populations, and settings.
The Effects of Local Police Surges on Crime and Arrests in New York City

The New York Police Department (NYPD) under Operation Impact deployed extra police officers to high crime areas designated as impact zones. Officers were encouraged to conduct investigative stops in these areas. City officials credited the program as one of the leading causes of New York City’s low crime rate. We tested the effects of Operation Impact on reported crimes and arrests from 2004 to 2012 using a difference-in-differences approach. We used Poisson regression models to compare differences in crime and arrest counts before and after census block groups were designated as impact zones compared to census block groups in the same NYPD precincts but outside impact zones. Impact zones were significantly associated with reductions in total reported crimes, assaults, burglaries, drug violations, misdemeanor crimes, felony property crimes, robberies, and felony violent crimes. Impact zones were significantly associated with increases in total reported arrests, arrests for burglary, arrests for weapons, arrests for misdemeanor crimes, and arrests for property felony crimes. Impact zones were also significantly associated with increases in investigative stops for suspected crimes, but only the increase in stops made based on probable cause indicators of criminal behaviors were associated with crime reductions. The largest increase in investigative stops in impact zones was based on indicators of suspicious behavior that had no measurable effect on crime. The findings suggest that saturating high crime blocks with police helped reduce crime in New York City, but that the bulk of the investigative stops did not play an important role in the crime reductions. The findings indicate that crime reduction can be achieved with more focused investigative stops.
Radiosurgery for Medial Temporal Lobe Epilepsy Resulting from Mesial Temporal Sclerosis

Medial temporal lobe epilepsy associated with mesial temporal sclerosis (MTS) is perhaps the most well-defined epilepsy syndrome that is responsive to structural interventions such as surgery. Several minimally invasive techniques have arisen that provide additional options for the treatment of MTS while potentially avoiding many of open surgery's associated risks. By evading these risks, they also open up treatment options to patients who otherwise are poor surgical candidates. Radiosurgery is one of the most intensively studied of these alternatives and has found a growing role in the treatment of medial temporal lobe epilepsy.
Exercise training increases L-type calcium current density in coronary smooth muscle

Exercise training produces numerous adaptations in the coronary circulation, including an increase in coronary tone, both in conduit and resistance arteries. On the basis of the importance of volta...
The Impact of Governance on Economic Growth: The Case of Middle Eastern and North African Countries

The main goal of this paper is to evaluate the impact of governance on economic growth using a group of 188 countries. Although our main focus is on the 21 Middle Eastern and North African (MENA) countries, our findings can be applied to the other countries as well. There are two main contributions in this paper. The first contribution is we are able to create a “composite governance index” (CGI) that summarizes the existing six governance measurements; the Worldwide Governance Indicators (WGI), using the Principal Components Analysis (PCA) method. The first principal component derived from the WGIs explains as large as 81% of the variations in the original six WGI measurements, which indicates that it can be used as a strong indicator for evaluating government’s managerial ability and effectiveness. Following the creation of CGI, the second contribution is we are able to quantify the marginal contribution of improvement in governance to economic performance using PPP adjusted constant per capita GDP data. We find that the per capita GDP would rise by about 2% if the CGI increases by one unit. Using the Rule of 70, the marginal estimate further indicates a mere five-unit improvement in CGI would double the country’s per capita GDP in seven years. Nonetheless, the effect of improvement of governance can not account for the higher than expected per capita GDP in most of the oil rich MENA countries. In other words, the majority of the MENA countries have achieved fragile levels of economic growth that does not depend on sound governance.
Towards eco-friendly home networking

Abstract Home networking is becoming increasingly sophisticated as users connect ever more networked devices. In the past, home networks typically consisted of a simple router and maybe a few computers. Now, high speed wireless networks are commonplace in homes with a large number of devices: TVs, game consoles, home theater systems, and even home automation systems. This is in addition to standard computing devices such as desktops, laptops, tablets, smart phones and network-attached storage. Smart homes with many wireless sensors to improve quality of life are also emerging. However, home network devices such as routers and broadband modems have been designed for maximum performance with limited consideration of energy optimization when the devices are idle or serving low bandwidth traffic. The goal of this paper is to analyze network activity of wireless home routers, investigate opportunities for energy saving, and present mechanisms for improving the energy efficiency of wireless home routers. We analyzed five week-long traces of home network traffic and identified a number of energy saving opportunities. Through detailed trace-based simulation and implementation measurements we are able to reduce the wireless energy consumption of the home router by 12–59% while incurring only minor delay of the initial packet delivery after leaving the low energy state. Modification of an actual router's behavior shows that the proposed energy optimizations are feasible with existing clients.
Aggregate fluctuations and the industry structure of the US economy

Abstract In a two-sector economy, changes in intermediate input trade as reflected in cost share fluctuations are key to determining the amplification properties of investment-specific and neutral shocks. I document that the cost shares of intermediate inputs produced by the investment sector correlate positively with GDP, whereas those of inputs produced by the consumption sector correlate negatively with GDP. The two-sector model of Greenwood et al. (1988) is extended to allow for trade of intermediate goods and to show that the documented correlations discipline heterogeneous elasticities of substitution in intermediate inputs across sectors. Shock amplification — that is, the effect of a sectorial shock on aggregate value added — depends on the degree of heterogeneity in these elasticities of substitution. For a calibrated economy to that of the United States, I find that shock amplification is stronger than in a unitary elasticity economy. It is also stronger than in an economy with a common non-unitary elasticity that is either inferred from data via reduced-form estimates, or calibrated to match the same targets as our benchmark economy.
On mesh restrictions to satisfy comparison principles, maximum principles, and the non-negative constraint: Recent developments and new results

ABSTRACTThis paper concerns with mesh restrictions that are needed to satisfy several important mathematical properties—maximum principles, comparison principles, and the nonnegative constraint—for a general linear second-order elliptic partial differential equation. We critically review some recent developments in the field of discrete maximum principles, derive new results, and discuss some possible future research directions in this area. In particular, we derive restrictions for a three-node triangular (T3) element and a four-node quadrilateral (Q4) element to satisfy comparison principles, maximum principles, and the nonnegative constraint under the standard single-field Galerkin formulation. Analysis is restricted to uniformly elliptic linear differential operators in divergence form with Dirichlet boundary conditions specified on the entire boundary of the domain. Various versions of maximum principles and comparison principles are discussed in both continuous and discrete settings. In the literatu...