cssi/SciSciGPT-SciSciNet huggingface dataset:
Dynamic Load Partitioning Strategies for Managing Data of Space and Time Heterogeneity in Parallel SAMR Applications

This paper presents the design and experimental evaluation of two dynamic load partitioning and balancing strategies for parallel Structured Adaptive Mesh Refinement (SAMR) applications: the Level-based Partitioning Algorithm (LPA) and the Hierarchical Partitioning Algorithm (HPA). These techniques specifically address the computational and communication heterogeneity across refinement levels of the adaptive grid hierarchy underlying these methods. An experimental evaluation of the partitioning schemes is also presented.
DISCOVERY OF A NEARLY EDGE-ON DISK AROUND HD 32297

We report the discovery of a nearly edge-on disk about the A0 star HD 32297 seen in light scattered by the disk grains revealed in NICMOS PSF-subtracted coronagraphic images. The disk extends to a distance of at least 400 AU (33) along its major axis with a 1.1 μm flux density of 4.81 ± 0.57 mJy beyond a radius of 03 from the coronagraphically occulted star. The fraction of 1.1 μm starlight scattered by the disk, 0.0033 ± 0.0004, is comparable to its fractional excess emission at 25 + 60 μm of ~0.0027 as measured from IRAS data. The disk appears to be inclined 105 ± 25 from an edge-on viewing geometry, with its major axis oriented 2365 ± 1° eastward of north. The disk exhibits unequal brightness on opposing sides and a break in the surface brightness profile along the NE-side disk major axis. Such asymmetries might implicate the existence of one or more (unseen) planetary mass companions.
Upper bounds on the torque in cylindrical Couette flow

Upper bounds on the torque are derived for a fluid that is contained between two concentric rotating cylinders. Absolute upper bounds are obtained by requiring that the fluid satisfy the boundary conditions and the dissipation integral. Improved bounds are then found by requiring that the fluid satisfy continuity conditions. These bounds are in qualitative agreement with the data in that they reflect the asymptotic parameter dependence in the range of experimental data.
Interrogating Racism: Toward an Antiracist Anthropology

AbstractOver the past several decades, global manifestations of racism have undergone significant transformations. The anticolonial struggle, the civil rights movement, and the antiapartheid offensive have challenged the former established racial regimes. But the consolidation of global capitalism has also created new forms of racialization. A variety of antiracist strategies and interventions have emerged to confront new racisms. Analyses of racism have sought to interrogate its history and contemporary manifestations, how it is maintained and reproduced, and to predict its future. Anthropologists and other social scientists are challenged to develop theoretical perspectives and methodological approaches to advance our understanding of these new manifestations of race and racism.
Mean curvature flows and isotopy of maps between spheres

Let f be a smooth map between unit spheres of possibly different dimensions. We prove the global existence and convergence of the mean curvature flow of the graph of f under various conditions. A corollary is that any area-decreasing map between unit spheres (of possibly different dimensions) is isotopic to a constant map. c � 2004 Wiley Periodicals, Inc.
Prevention and management of travelers' diarrhea.

ravelers’ diarrhea (TD) is one of the most common medical conditions xperienced by individuals from an industrialized country who travel to a eveloping country. Fortunately, the mortality associated with TD is xtremely low (even in children); however, it can be a frustrating ondition forcing changes in travel plans and causing general discomfort. D is a potentially preventable and treatable condition. A health care rofessional preparing a family for international travel can play an mportant role in educating the family members about prevention, rophylaxis, and emergency treatment of TD.
Optimizing Vetoes for Gravitational-wave Transient Searches

Interferometric gravitational-wave detectors like LIGO, GEO600 and Virgo record a surplus of information above and beyond possible gravitational-wave events. These auxiliary channels capture information about the state of the detector and its surroundings which can be used to infer potential terrestrial noise sources of some gravitational-wave-like events. We present an algorithm addressing the ordering (or equivalently optimizing) of such information from auxiliary systems in gravitational-wave detectors to establish veto conditions in searches for gravitational-wave transients. The procedure was used to identify vetoes for searches for unmodelled transients by the LIGO and Virgo collaborations during their science runs from 2005 through 2007. In this work we present the details of the algorithm; we also use a limited amount of data from LIGO's past runs in order to examine the method, compare it with other methods, and identify its potential to characterize the instruments themselves. We examine the dependence of Receiver Operating Characteristic curves on the various parameters of the veto method and the implementation on real data. We find that the method robustly determines important auxiliary channels, ordering them by the apparent strength of their correlations to the gravitational-wave channel. This list can substantially reduce the background of noise events in the gravitational-wave data. In this way it can identify the source of glitches in the detector as well as assist in establishing confidence in the detection of gravitational-wave transients.
Residuals‐based tests for the null of no‐cointegration: an Analytical comparison

. This article studies the asymptotic distribution of five residuals-based tests for the null of no-cointegration under a local alternative when the tests are computed using both ordinary least squares (OLS) and generalized least squares (GLS)-detrended variables. The local asymptotic power of the tests is shown to be a function of Brownian motion and Ornstein–Uhlenbeck processes, depending on a single nuisance parameter, which is determined by the correlation at frequency zero of the errors of the cointegration regression with the shocks to the right-hand side variables. The tests are compared in terms of power in large and small samples. It is shown that, while no significant improvement can be achieved by using unit root tests other than the OLS detrended t-test originally proposed by Engle and Granger (1987), the power of GLS residuals tests can be higher than the power of system tests for some values of the nuisance parameter.
Evolution of Mercury's obliquity

Abstract Mercury has a near-zero obliquity, i.e. its spin axis is nearly perpendicular to its orbital plane. The value of the obliquity must be known precisely in order to constrain the size of the planet's core within the framework suggested by Peale [Peale, S.J., 1976. Nature 262, 765–766]. Rambaux and Bois [Rambaux, N., Bois, E., 2004. Astron. Astrophys. 413, 381–393] have suggested that Mercury's obliquity varies on thousand-year timescales due to planetary perturbations, potentially ruining the feasibility of Peale's experiment. We use a Hamiltonian approach (free of energy dissipation) to study the spin–orbit evolution of Mercury subject to secular planetary perturbations. We can reproduce an obliquity evolution similar to that of Rambaux and Bois [Rambaux, N., Bois, E., 2004. Astron. Astrophys. 413, 381–393] if we integrate the system with a set of initial conditions that differs from the Cassini state. However the thousand-year oscillations in the obliquity disappear if we use initial conditions corresponding to the equilibrium position of the Cassini state. This result indicates that planetary perturbations do not force short-period, large amplitude oscillations in the obliquity of Mercury. In the absence of excitation processes on short timescales, Mercury's obliquity will remain quasi-constant, suggesting that one of the important conditions for the success of Peale's experiment is realized. We show that interpretation of data obtained in support of this experiment will require a precise knowledge of the spin–orbit configuration, and we provide estimates for two of the critical parameters, the instantaneous Laplace plane orientation and the orbital precession rate from numerical fits to ephemeris data. Finally we provide geometrical relationships and a scheme for identifying the correct initial conditions required in numerical integrations involving a Cassini state configuration subject to planetary perturbations.
High resolution conjugate filters for the simulation of flows

This paper proposes a Hermite-kernel realization of the conjugate filter oscillation reduction (CFOR) scheme for the simulation of fluid flows. The Hermite kernel is constructed by using the discrete singular convolution (DSC) algorithm, which provides a systematic generation of low-pass filter and its conjugate high-pass filters. The high-pass filters are utilized for approximating spatial derivatives in solving flow equations, while the conjugate low-pass filter is activated to eliminate spurious oscillations accumulated during the time evolution of a flow. As both low-pass and high-pass filters are derived from the Hermite kernel, they have similar regularity, time-frequency localization, effective frequency band and compact support. Fourier analysis indicates that the CFOR-Hermite scheme yields a nearly optimal resolution and has a better approximation to the ideal low-pass filter than previous CFOR schemes. Thus, it has better potential for resolving natural high frequency oscillations from a shock. Extensive one- and two-dimensional numerical examples, including both incompressible and compressible flows, with or without shocks, are employed to explore the utility, test the resolution, and examine the stability of the present CFOR-Hermite scheme. Small ratio of point-perwavelength (PPW) is achieved in advancing a wavepacket and resolving a shock/entropy wave interaction. The present results for the advection of an isentropic vortex compare very favorably to those in the literature.
Supergravity, the DBI action and black hole physics

Abstract The assumptions behind the recently conjectured relation between gauge theory and supergravity are elaborated on. It is pointed out that the scaling limit that preserves supergravity solutions, gives the entire DBI action on the gauge theory side, but in the low energy limit the relation between the conformal field theory and Anti-de Sitter supergravity emerges. We also argue that recent work on these issues may help in understanding the physics of five (four) dimensional black hole with three (four) charges in the so-called dilute gas region.
Multiresolution Gaussian Processes

We propose a multiresolution Gaussian process to capture long-range, non-Markovian dependencies while allowing for abrupt changes and non-stationarity. The multiresolution GP hierarchically couples a collection of smooth GPs, each defined over an element of a random nested partition. Long-range dependencies are captured by the top-level GP while the partition points define the abrupt changes. Due to the inherent conjugacy of the GPs, one can analytically marginalize the GPs and compute the marginal likelihood of the observations given the partition tree. This property allows for efficient inference of the partition itself, for which we employ graph-theoretic techniques. We apply the multiresolution GP to the analysis of magnetoencephalography (MEG) recordings of brain activity.
Pitfalls and Prospects in the Peacekeeping Literature

Following closely the practice of peacekeeping, the literature on the subject has come in one small wave and then two larger ones. The first wave, during the Cold War, includes classic works focusing mainly on peacekeeping in wars between states. The second wave, at first inspired by the boom in peacekeeping shortly after the end of the Cold War, soon reflected disillusionment and focuses largely on failure and dysfunction, despite significant cases of success. The third and most recent wave also reflects a resurgence in peacekeeping but is newly concerned with systematic and methodologically rigorous analysis (both quantitative and qualitative) of basic empirical questions about the effects of peacekeeping and the sources of peacekeeping outcomes. Recent empirical studies have demonstrated peacekeeping's effectiveness in maintaining peace, but related questions persist concerning the use of force, transitional administrations, which organizations most effectively keep peace, perspectives of the “peacekep...
Limitations of Hall MHD as a model for turbulence in weakly collisional plasmas

Abstract. The limitations of Hall MHD as a model for turbulence in weakly collisional plasmas are explored using quantitative comparisons to Vlasov-Maxwell kinetic theory over a wide range of parameter space. The validity of Hall MHD in the cold ion limit is shown, but spurious undamped wave modes exist in Hall MHD when the ion temperature is finite. It is argued that turbulence in the dissipation range of the solar wind must be one, or a mixture, of three electromagnetic wave modes: the parallel whistler, oblique whistler, or kinetic Alfven waves. These modes are generally well described by Hall MHD. Determining the applicability of linear kinetic damping rates in turbulent plasmas requires a suite of fluid and kinetic nonlinear numerical simulations. Contrasting fluid and kinetic simulations will also shed light on whether the presence of spurious wave modes alters the nonlinear couplings inherent in turbulence and will illuminate the turbulent dynamics and energy transfer in the regime of the characteristic ion kinetic scales.
A new route to furanoeremophilane sesquiterpenoids. Synthesis of (±)-6β-hydroxyeuryopsin

The naturally occurring furanoeremophilane 6β-hydroxyeuryopsin was synthesized by a novel route which involved Stille coupling of a 2-furylstannane with a cyclohexylmethyl bromide, followed by intramolecular formylation of the furan to complete the tricyclic nucleus of the sesquiterpenoid.
Firm Birth and Death in U.S. Manufacturing: A Regional Adjustment Model

Attracting manufacturing investment is a frequently used rural development policy. Previous research in the location literature has informed policymakers which factors are most important for attracting new firm investment. Far less is known about the interaction of birth and death of establishments. A conceptual model of county-level investment in the U.S. manufacturing sector is developed from location theory and subsequent literature. Specifically, we test the relative importance of location factors influencing firm investment, and if these factors influence firm birth and death differently. Local factors include agglomeration due to localization, urbanization, and internal economies, market structure, labor quality, availability, and cost, market conditions, , infrastructure, and fiscal policy. This study covers the time period 2000 to 2004 for U.S. counties in the lower 48 states. Counts of establishments are from the U.S. Census Bureau’s Dynamic Firm Data Series, which links establishments across space and time. Negative binomial models containing spatially lagged endogenous variables are estimated in a regional adjustment framework to show how ceteris paribus changes in location factors affect the conditional number of establishment births and deaths in a county.
Invariance of fluid limits for the shortest remaining processing time and shortest job first policies

We consider a single-server queue with renewal arrivals and i.i.d. service times, in which the server employs either the preemptive Shortest Remaining Processing Time (SRPT) policy, or its non-preemptive variant, Shortest Job First (SJF). We show that for given stochastic primitives (initial condition, arrival and service processes), the model has the same fluid limit under either policy. In particular, we conclude that the well-known queue length optimality of preemptive SRPT is also achieved, asymptotically on fluid scale, by the simpler-to-implement SJF policy. We also conclude that on fluid scale, SJF and SRPT achieve the same performance with respect to state-dependent response times.
Photonic crystal laser accelerator structures

Photonic crystals have great potential for use as laser-driven accelerator structures. A photonic crystal is a dielectric structure arranged in a periodic geometry. Like a crystalline solid with its electronic band structure, the modes of a photonic crystal lie in a set of allowed photonic bands. Similarly, it is possible for a photonic crystal to exhibit one or more photonic band gaps, with frequencies in the gap unable to propagate in the crystal. Thus photonic crystals can confine an optical mode in an all-dielectric structure, eliminating the need for metals and their characteristic losses at optical frequencies. We discuss several geometries of photonic crystal accelerator structures. Photonic crystal fibers (PCFs) are optical fibers which can confine a speed-of-light optical mode in vacuum. Planar structures, both two- and three-dimensional, can also confine such a mode, and have the additional advantage that they can be manufactured using common microfabrication techniques such as those used for integrated circuits. This allows for a variety of possible materials, so that dielectrics with desirable optical and radiation-hardness properties can be chosen. We discuss examples of simulated photonic crystal structures to demonstrate the scaling laws and trade-offs involved, and touch on potential fabrication processes.
MPI-StarT: Delivering Network Performance to Numerical Applications

We describe an MPI implementation for a cluster of SMPs interconnected by a high- performance interconnect. This work is a collaboration between a numerical applications programmer and a cluster interconnect architect. The collaboration started with the modest goal of satisfying the communication needs of a specific numerical application, MITMatlab. However, by supporting the MPI standard MPI-StarT readily extends support to a host of applications. MPI-StarT is derived from MPICH by developing a custom implementation of the Channel Interface. Some changes in MPICH's ADI and Protocol Layers are also necessary for correct and optimal operation. MPI-StarT relies on the host SMPs' shared memory mechanism for intra-SMP communication. Inter-SMP communication is supported through StarT-X. The StarT-X NIU allows a cluster of PCI-equipped host platforms to communicate over the Arctic Switch Fabric. Currently, StarT-X is utilized by a cluster of SUN E5000 SMPs as well as a cluster of Intel Pentium-II workstations. On a SUN E5000 with StarT-X, a processor can send and receive a 64-byte message in less than 0.4 and 3.5 usec respectively and incur less than 5.6 usec user-to-user one-way latency. StarT-X's remote memory-to-memory DMA mechanism can transfer large data blocks at 60 MByte/sec between SUN E5000s. This paper outlines our effort to preserve and deliver this level of communication performance through MPI-StarT to user applications. We have studied the requirements of MITMatlab and the capabilities of StarT-X and have formulated an implementation strategy for the Channel Interface. In this paper, we discuss some performance and correctness issues and their resolutions in MPI-StarT. The correctness issues range from the handling of arbitrarily large message sizes to deadlock-free support of nonblocking MPI operations. Performance optimizations include a shared-memory-based transport mechanism for intra- SMP communication and a broadcast mechanism that is aware of the performance difference between intra-SMP and the slower inter-SMP communication. We characterize the performance of MPI-StarT on a cluster of SUN E5000s. On SUN E5000s, MPI processes within the same SMP can communicate at over 150 MByte/sec using shared memory. When communicating between SMPs over StarT-X, MPI-StarT has a peak bandwidth of 56 MByte/sec. While fine-tuning of MPI-StarT is ongoing, we demonstrate that MPI-StarT is effective in enabling the speedup of MITMatlab on a cluster of SMPs by reporting on the performance of some representative numerical operations.
Feature selection for linear SVM with provable guarantees

We give two provably accurate feature-selection techniques for the linear SVM. The algorithms run in deterministic and randomized time respectively. Our algorithms can be used in an unsupervised or supervised setting. The supervised approach is based on sampling features from support vectors. We prove that the margin in the feature space is preserved to within ź-relative error of the margin in the full feature space in the worst-case. In the unsupervised setting, we also provide worst-case guarantees of the radius of the minimum enclosing ball, thereby ensuring comparable generalization as in the full feature space and resolving an open problem posed in Dasgupta et al. (2007) 7. We present extensive experiments on real-world datasets to support our theory and to demonstrate that our method is competitive and often better than prior state-of-the-art, for which there are no known provable guarantees. HighlightsWe give two provably accurate feature-selection techniques for the linear SVM.Algorithms can be used in supervised or unsupervised setting.We prove margin is preserved to within e-relative error in the full feature space.In unsupervised case, we provide worst-case guarantees of margin and radius of minimum enclosing ball.Extensive experiments demonstrate that our method is competitive and often better than prior art.
Economic Value of Celebrity Endorsements: Tiger Woods' Impact on Sales of Nike Golf Balls

In this paper we quantify the economic worth of celebrity endorsements by studying the sales of endorsed products. We do so with the use of two unique data sets consisting of monthly golf ball sales and professional golfer celebrity rankings. In particular, we examine the impact Tiger Woods had on sales of Nike golf balls. Our identification of the causal effect of a celebrity is grounded in the celebrity's random performance over time. Using two different approaches, reduced form and structural, we find that there are substantial celebrity endorsement effects. From our structural model, we determine that endorsements not only induce consumers to switch brands, a business stealing effect, but also have a primary demand effect. We determine that from 2000 to 2010, the Nike golf ball division reaped an additional profit of $103 million through the acquisition of 9.9 million in sales from Tiger Woods' endorsement effect. Moreover, having Tiger Woods' endorsement led to a price premium of roughly 2.5%. As a result, approximately 57% of Nike's investment in Woods' $181 million endorsement deal was recovered just in U.S. golf ball sales alone.
Cosmopolitans or Locals: Who Will Lead the Next Generation of Community Colleges?

The impact of cosmopolitan and local latent social roles on different professional occupations and organizational behavior has been studied since Gouldner’s seminal study was published in 1957. This study was conducted to understand the relationship between the latent social role of the public community college chief academic officer and his or her intent to pursue a community college presidency.
A lossless metamaterial with tunable permittivity and its application as a compact phase shifter

In this paper, we propose a new type of lossless metamaterial whose effective permittivity is tunable from negative to positive values. Its optical response is studied analytically and numerically. We further demonstrate that this tunable metamaterial can significantly modulate the phase of an incident pulse with negligible reflection loss, functioning as an efficient phase shifter.
Distributed Navigation Algorithms for Sensor Networks

We propose efficient distributed algorithms to aid navigation of a user through a geographic area covered by sensors. The sensors sense the level of danger at their locations and we use this information to find a safe path for the user through the sensor field. Traditional distributed navigation algorithms rely upon flooding the whole network with packets to find an optimal safe path. To reduce the communication expense, we introduce the concept of a skeleton graph which is a sparse subset of the true sensor network communication graph. Using skeleton graphs we show that it is possible to find approximate safe paths with much lower communication cost. We give tight theoretical guarantees on the quality of our approximation and by simulation, show the effectiveness of our algorithms in realistic sensor network situations.
Equal gain transmission in multiple-input multiple-output wireless systems

Multiple-input multiple-output (MIMO) wireless systems are of interest due to their ability to provide substantial gains in capacity and quality. The paper proposes equal gain transmission (EGT) to provide diversity advantage in MIMO systems experiencing Rayleigh fading. The applications of EGT with selection diversity combining, equal gain combining, and maximum ratio combining are addressed. It is proven that systems using EGT with any of these combining schemes achieve full diversity order when transmitting over a memoryless, flat-fading Rayleigh matrix channel with independent entries. Since, in practice, full channel knowledge at the transmitter is difficult to realize, a quantized version of EGT is proposed. An algorithm to construct a beamforming vector codebook that guarantees full diversity order is presented. Monte-Carlo simulation comparisons with various beamforming and combining systems illustrate the performance as a function of quantization.
Dynamical evolution of the Hungaria asteroids

The Hungarias are a stable asteroid group orbiting between Mars and the main asteroid belt, with high inclinations (16–30), low eccentricities (e < 0.18), and a narrow range of semi-major axes (1.78– 2.06 AU). In order to explore the significance of thermally-induced Yarkovsky drift on the population, we conducted three orbital simulations of a 1000-particle grid in Hungaria a–e–i space. The three simulations included asteroid radii of 0.2, 1.0, and 5.0 km, respectively, with run times of 200 Myr. The results show that mean motion resonances—martian ones in particular—play a significant role in the destabilization of asteroids in the region. We conclude that either the initial Hungaria population was enormous, or, more likely, Hungarias must be replenished through collisional or dynamical means. To test the latter possibility, we conducted three more simulations of the same radii, this time in nearby Mars-crossing space. We find that certain Mars crossers can be trapped in martian resonances, and by a combination of chaotic diffusion and the Yarkovsky effect, can be stabilized by them. Therefore, some Hungarias (around 5% of non-family members with absolute magnitudes H < 15.5 and 10% for H < 17) may represent previously transient Mars crossers that have been adopted in this manner.
Equilibrium participation in public goods allocations

We consider a notion of voluntary participation for mechanism design in public goods economies in which mechanisms select public goods allocations and individuals then choose whether or not to submit their requested transfer to the central planner. The set of allocations that are robust to non-participation is shown to be sub-optimal in a wide variety of environments and may shrink to the endowment as the economy is replicated. When agents become small as the economy becomes large, any non-trivial mechanism suffers from non-participation when agents cannot be coerced to contribute.
Under‐representation of women in high‐impact published clinical cancer research

BACKGROUND. Adequate representation of women in research has been deemed essential. METHODS. Cancer research published in 8 journals in 2006 was reviewed. The percentage of women among study participants was compared with the proportion expected from population-based estimates of sex-specific cancer incidence, using binomial tests. Differences were assessed in sex distribution of participants by funding source, author sex, and focus of research with the Student t test, and in a linear regression model controlling for cancer type. RESULTS. A total of 1534 cancer research articles were identified, of which 661 (representing 1,096,098 participants) were prospective clinical studies and were analyzed further. For all 7 nonsex–specific cancer types assessed, the majority of studies analyzed included a lower proportion of women than the proportion of women among patients having cancer of that type in the general population. Among studies focusing on cancer treatment, women constituted a significantly lower overall proportion of the participants in the analyzed studies than expected for 6 of 7 non-sex–specific cancer types (P < .001). Among non-sex–specific studies, the mean percentage of participants who were women was 38.8%. Nonsex–specific studies reporting government funding had a higher percentage of female participants (mean 41.3% vs 36.9%; P ¼ .005). In a regression model controlling for cancer type, lack of government funding (P ¼ .03) and focus on cancer treatment (P ¼ .03) were found to be independent significant predictors of a lower percentage of female participants. CONCLUSIONS. Women were under-represented as participants in recently published, high-impact studies of non-sex–specific cancers. Studies that received government funding included a higher proportion of female subjects. Cancer 2009;115:3293–301. V C 2009 American
Catalytic asymmetric synthesis of chiral allylic amines. Evaluation of ferrocenyloxazoline palladacycle catalysts and imidate motifs.

Palladium(II) catalysts based on a ferrocenyloxazoline palladacyclic (FOP) scaffold were synthesized and evaluated for the rearrangement of prochiral allylic N-(4-methoxyphenyl)benzimidates. When iodide-bridged dimer FOP precatalysts are activated by reaction with excess silver trifluoroacetate, the allylic rearrangement of both E and Z prochiral primary allylic N-(4-methoxyphenyl)benzimidates takes place at room temperature to give the corresponding chiral allylic N-(4-methoxyphenyl)benzamides in high yield and good ee (typically 81−95%). Several allylic imidate motifs were evaluated also. Because the corresponding enantioenriched allylic amide products can be deprotected in good yield to give enantioenriched allylic amines, allylic N-aryltrifluoroacetimidates were identified as promising substrates.
Phenylsulfonyl ene-allenes as efficient precursors to bicyclic systems via intramolecular [2 + 2]-cycloaddition reactions.

Various phenylsulfonyl allene derivatives were prepared with double bonds tethered either to the α-position or the γ-position of the allene. These substrates underwent a highly regio- and stereospecific thermal [2 + 2]-cycloaddition across the nonactivated cumulene double bond, forming distal cycloadducts (i.e., 57) in the case of α-tethered allenes and proximal adducts (i.e., 25) in the case of γ-tethered allenes. The mechanistic rationale for the observed stereospecificity involves initial diradical formation, followed by a rapid ring closure to the more stable cis-fused ring system. The tether may be equipped with heteroatoms, allowing for the formation of fused heterocycles (e.g., 61), and the cycloaddition can be facilitated by the introduction of sterically bulky groups and/or by conformational rigidity to the tether. Other modes of cyclization were observed in the presence of sodium benzenesulfinate or Lewis acids, in which cases polar mechanisms prevail. The chemoselectivity is reversed for [4 + 2...
An identity-based single-sign-on scheme for computer networks

Conventionally, no user identification is required for a user to log into a security-protected system. User authentication is based on what the user knows, or what the user has, which can be easily shared among others. Moreover, when multiple systems are involved, the user is then required to authenticate to each system individually and repeatedly. In this paper, we present a scheme to achieve secure user identification and authentication to multiple security-protected systems simultaneously through a single operation. The proposed scheme is based on the well-known RSA cryptosystem, the discrete logarithm problem, and the subset-sum NP-complete problem. Security analysis shows that the proposed scheme is secure to all known security attacks and can be easily implemented in various environments including very resource constrained environment such as Smart Cards. Copyright © 2008 John Wiley & Sons, Ltd.
Spurious Signals in TRMM/VIRS Reflectance Channels and Their Effect on Aerosol Retrievals

Abstract Aerosol optical depths, τ1 and τ2, and the Angstrom exponent α = –ln(τ1/τ2)/ln(λ1/λ2), are retrieved from daytime measurements (sun zenith angle θo < 60°) over ocean in reflectance bands 1 (λ1 = 0.63 µm) and 2 (λ2 = 1.61 µm) of the five-channel visible and infrared scanner (VIRS) on board the Tropical Rainfall Measuring Mission (TRMM) satellite. In band 2, a thermal leak originating from the secondary spectral response peak at ∼5.2 µm contributes radiance comparable to the signal scattered by aerosols. In the past two corrections, the thermal signal was parameterized empirically as a linear function of radiances in bands 4 and 5 (centered at 10.8 and 11.9 µm, respectively), R4 and R5, and a quadratic function of view angle θ through multiple regression analyses. The regression coefficients were estimated from a limited amount of all-sky nighttime (100° < θo < 170°) data over land and ocean, and were used to predict and remove the false signal from daytime data. As a result, retrievals of τ2 and α...
Learning a Discriminative Model for the Perception of Realism in Composite Images

What makes an image appear realistic? In this work, we are answering this question from a data-driven perspective by learning the perception of visual realism directly from large amounts of data. In particular, we train a Convolutional Neural Network (CNN) model that distinguishes natural photographs from automatically generated composite images. The model learns to predict visual realism of a scene in terms of color, lighting and texture compatibility, without any human annotations pertaining to it. Our model outperforms previous works that rely on hand-crafted heuristics, for the task of classifying realistic vs. unrealistic photos. Furthermore, we apply our learned model to compute optimal parameters of a compositing method, to maximize the visual realism score predicted by our CNN model. We demonstrate its advantage against existing methods via a human perception study.
Hf3Fe4Sn4 and Hf9Fe4−xSn10+x: Two stannide intermetallics with low-dimensional iron sublattices

Abstract This article reports two new Hf-rich intermetallics synthesized using Sn flux: Hf 3 Fe 4 Sn 4 and Hf 9 Fe 4− x Sn 10+ x . Hf 3 Fe 4 Sn 4 adopts an ordered variant the Hf 3 Cu 8 structure type in orthorhombic space group Pnma with unit cell edges of a =8.1143(5) A, b =8.8466(5) A, and c =10.6069(6) A. Hf 9 Fe 4− x Sn 10+ x , on the other hand, adopts a new structure type in Cmc 2 1 with unit cell edges of a =5.6458(3) A, b =35.796(2) A, and c =8.88725(9) A for x =0. It exhibits a small amount of phase width in which Sn substitutes on one of the Fe sites. Both structures are fully three-dimensional and are characterized by pseudo one- and two-dimensional networks of Fe–Fe homoatomic bonding. Hf 9 Fe 4− x Sn 10+ x exhibits antiferromagnetic order at T N =46(2) K and its electrical transport behavior indicates that it is a normal metal with phonon-dictated resistivity. Hf 3 Fe 4 Sn 4 is also an antiferromagnet with a rather high ordering temperature of T N =373(5) K. Single crystal resistivity measurements indicate that Hf 3 Fe 4 Sn 4 behaves as a Fermi liquid at low temperatures, indicating strong electron correlation.
Pricing and referrals in diffusion on networks

Abstract When a new product or technology is introduced, potential consumers can learn its quality by trying it, at a risk, or by letting others try it and free-riding on the information that they generate. We propose a dynamic game to study the adoption of technologies of uncertain value, when agents are connected by a network and a monopolist seller chooses a profit-maximizing policy. Consumers with low degree (few friends) have incentives to adopt early, while consumers with high degree have incentives to free ride. The seller can induce high-degree consumers to adopt early by offering referral incentives – rewards to early adopters whose friends buy in the second period. Referral incentives thus lead to a ‘double-threshold strategy’ by which low and high-degree agents adopt the product early while middle-degree agents wait. We show that referral incentives are optimal on certain networks while inter-temporal price discrimination is optimal on others.
Shape dependence of entanglement entropy in conformal field theories

We study universal features in the shape dependence of entanglement entropy in the vacuum state of a conformal field theory (CFT) on $$ {\mathrm{\mathbb{R}}}^{1,d-1} $$ . We consider the entanglement entropy across a deformed planar or spherical entangling surface in terms of a perturbative expansion in the infinitesimal shape deformation. In particular, we focus on the second order term in this expansion, known as the entanglement density. This quantity is known to be non-positive by the strong-subadditivity property. We show from a purely field theory calculation that the non-local part of the entanglement density in any CFT is universal, and proportional to the coefficient C T appearing in the two-point function of stress tensors in that CFT. As applications of our result, we prove the conjectured universality of the corner term coefficient $$ \frac{\sigma }{C_T}=\frac{\pi^2}{24} $$ in d = 3 CFTs, and the holographic Mezei formula for entanglement entropy across deformed spheres.
Development of an Ontology to Model Medical Errors, Information Needs, and the Clinical Communication Space

Medical errors are common, costly and often preventable. Work in understanding the proximal causes of medical errors demonstrates that systems failures predispose to adverse clinical events. Most of these systems failures are due to lack of appropriate information at the appropriate time during the course of clinical care. Problems with clinical communication are common proximal causes of medical errors. We have begun a project designed to measure the impact of wireless computing on medical errors. We report here on our efforts to develop an ontology representing the intersection of medical errors, information needs and the communication space. We will use this ontology to support the collection, storage and interpretation of project data. The ontology’s formal representation of the concepts in this novel domain will help guide the rational deployment of our informatics interventions. A real-life scenario is evaluated using the ontology in order to demonstrate its utility.
Three new sensitivity analysis methods for influence diagrams

Performing sensitivity analysis for influence diagrams using the decision circuit framework is particularly convenient, since the partial derivatives with respect to every parameter are readily available [Bhattacharjya and Shachter, 2007; 2008]. In this paper we present three non-linear sensitivity analysis methods that utilize this partial derivative information and therefore do not require re-evaluating the decision situation multiple times. Specifically, we show how to efficiently compare strategies in decision situations, perform sensitivity to risk aversion and compute the value of perfect hedging [Seyller, 2008].
Macroeconomic Regimes and Regime Shifts

Abstract Many economic time series exhibit dramatic breaks associated with events such as economic recessions, financial panics, and currency crises. Such changes in regime may arise from tipping points or other nonlinear dynamics and are core to some of the most important questions in macroeconomics. This chapter surveys the literature for studying regime changes and summarizes available methods. Section 1 introduces some of the basic tools for analyzing such phenomena, using for illustration the move of an economy into and out of recession. Section 2 focuses on empirical methods, providing a detailed overview of econometric analysis of time series that are subject to changes in regime. Section 3 discusses theoretical treatment of macroeconomic models with changes in regime and reviews applications in a number of areas of macroeconomics. Some brief concluding recommendations for applied researchers are offered in Section 4 .
Christina Merchant and the State of Dispute System Design

Christina Merchant made an important contribution to the field of dispute resolution through her teaching, writing, and training on dispute system design. Using principles of organization development, she brought a new organizational lens to thinking about dispute system design (DSD) beyond collective bargaining and grievance procedures; she looked at the whole organization, its many sources of, causes for, and ways to address conflict. With Cathy Costantino, her 1996 book provided a unique and influential resource for a field that has continued to grow. The field would benefit from broadening the academic literature that informs systems for managing conflict. Zooming out to the organization's nested institutional contexts, the work of Elinor Ostrom in political science and political economy provides the tools of institutional analysis for DSD. She also laid the groundwork for thinking about DSD in relation to governance, not only at the local but also at the state, regional, national, and international levels. By applying a more comprehensive analytic framework to DSD, conflict resolvers with DSD skills and expertise are poised to make important differences in emerging global systems for addressing conflict upstream in policy development, midstream in its implementation, and downstream in enforcement.
FlexiWi-Fi Security Manager Using Freescale Embedded System

Among the current Wi-Fi two security models (Enterprise and Personal), while the Enterprise model (802.1X) offers an effective framework for authenticating and controlling the user traffic to a protected network, the Personal model (802.11) offers the cheapest and the easiest to setup solution. However, the drawback of the personal model implementation is that all access points and client radio NIC on the wireless LAN should use the same encryption key. A major underlying problem of the 802.11 standard is that the pre-shared keys are cumbersome to change. So if those keys are not updated frequently, unauthorized users with some resources and within a short timeframe can crack the key and breach the network security. The purpose of this paper is to propose and implement an effective method for the system administrator to manage the users connected to a router, update the keys and further distribute them for the trusted clients using the Freescale embedded system, Infrared and Bluetooth modules.
SQUIRE 2.0-Standards for Quality Improvement Reporting Excellence-Revised Publication Guidelines from a Detailed Consensus Process.

Since the publication of Standards for QUality Improvement Reporting Excellence (SQUIRE 1.0) guidelines in 2008, the science of the field has advanced considerably. In this manuscript, we describe the development of SQUIRE 2.0 and its key components. We undertook the revision between 2012 and 2015 using (1) semi-structured interviews and focus groups to evaluate SQUIRE 1.0 plus feedback from an international steering group, (2) two face-to-face consensus meetings to develop interim drafts, and (3) pilot testing with authors and a public comment period. SQUIRE 2.0 emphasizes the reporting of three key components of systematic efforts to improve the quality, value, and safety of healthcare: the use of formal and informal theory in planning, implementing, and evaluating improvement work; the context in which the work is done; and the study of the intervention(s). SQUIRE 2.0 is intended for reporting the range of methods used to improve healthcare, recognizing that they can be complex and multidimensional. It provides common ground to share these discoveries in the scholarly literature (http://www.squire-statement.org).
Beyond organic chemistry: aromaticity in atomic clusters.

We describe joint experimental and theoretical studies carried out collaboratively in the authors' labs for understanding the structures and chemical bonding of novel atomic clusters, which exhibit aromaticity. The concept of aromaticity was first discovered to be useful in understanding the square-planar unit of Al4 in a series of MAl4− bimetallic clusters that led to discoveries of aromaticity in many metal cluster systems, including transition metals and similar cluster motifs in solid compounds. The concept of aromaticity has been found to be particularly powerful in understanding the stability and bonding in planar boron clusters, many of which have been shown to be analogous to polycyclic aromatic hydrocarbons in their π bonding. Stimulated by the multiple aromaticity in planar boron clusters, a design principle has been proposed for stable metal-cerntered aromatic molecular wheels of the general formula, M@Bnk−. A series of such borometallic aromatic wheel complexes have been produced in supersonic cluster beams and characterized experimentally and theoretically, including Ta@B10− and Nb@B10−, which exhibit the highest coordination number in two dimensions.
Conditional utility, utility independence, and utility networks

We introduce a new interpretation of two related notions - conditional utility and utility independence. Unlike the traditional interpretation, the new interpretation render the notions the direct analogues of their probabilistic counterparts. To capture these notions formally, we appeal to the notion of utility distribution, introduced in previous paper. We show that utility distributions, which have a structure that is identical to that of probability distributions, can be viewed as a special case of an additive multiattribute utility functions, and show how this special case permits us to capture the novel senses of conditional utility and utility independence. Finally, we present the notion of utility networks, which do for utilities what Bayesian networks do for probabilities. Specifically, utility networks exploit the new interpretation of conditional utility and utility independence to compactly represent a utility distribution.
Purchasing Power Parity: A Time Series Analysis of the U.S. and Mexico, 1995–2007

This paper presents indirect evidence that absolute purchasing power parity (PPP) may hold in the long-run between Mexico and the U.S., but due to data limitations, the relationship could not be tested directly. Thus it is not clear if absolute PPP holds in the long run between the U.S. and Mexico. Given that relative PPP is a necessary, but not sufficient, condition for absolute PPP to hold, this study tests the relationship between the change in the log of the exchange rate, and the changes in the log of the U.S. producer price index (PPI) and the Mexican PPI. Here, the absence of relative PPP would indicate that absolute PPP could not hold. Given that all the relevant variables in first difference log are stationary, PPP in its relative form holds and OLS can be applied directly in a VAR model setting, viz., treating all variables initially as potentially endogenous. The estimates indicate one-way Granger causality from the percentage change in the exchange rate to the percentage change in the Mexican price level, which is not an implausible result for an emerging nation such as Mexico which imports a significant fraction of (dollar denominated) intermediate products and capital inputs.