cssi/SciSciGPT-SciSciNet huggingface dataset:
The Systematic Design of Non-commensurate Impedance Matching Tapers for Ultra Wideband Gradient-Index (GRIN) Lens Antennas

We propose a general method for designing wideband matching tapers in inhomogeneous media where phase velocity is coupled to the taper impedance profile. Such tapers are used to match wideband gradient index (GRIN) lens antennas. To simplify fabrication tapers are often constrained to physically uniform layers wherein commensurate line theory cannot predict the frequency response. Therefore, we present a new design algorithm which derives an effective permittivity eff to equalize the electrical length of commensurate and non-commensurate line tapers. The algorithm provides a systematic design method with predictable frequency response for non-commensurate line tapers. Nevertheless, there are several unavoidable nonidealities present in such discretized tapers which we discuss and provide recommendations for mitigation. The algorithm is used to design a Klopfenstein taper with return loss better than 15 dB from 8 to 78 GHz. The design is fabricated and measurements agree with simulation across the WR90, WR28, and WR12 bands. An approximate efficiency formula is proposed which predicts aperture efficiency of taper-matched lenses without the need for time-consuming full-wave simulations. Various lenses are designed and compared to highlight the advantages of Klopfenstein tapers in GRIN lens design. The results demonstrate the usefulness of the proposed design method.
Vertical Mergers and Input Foreclosure Lessons from the AT&T/Time Warner Case

This article offers a practical guide to analyzing vertical mergers using the general approach to input foreclosure and raising rivals’ costs that is described in the 2020 Vertical Merger Guidelines that were issued by the U.S. Department of Justice and the Federal Trade Commission. The step-by-step analysis described here draws lessons from how that theory of harm played out in the lone vertical merger case that has been litigated by the antitrust agencies in recent decades: the 2018 challenge by the Department of Justice to the merger between AT&T and Time Warner. I testified in court as the DOJ’s economic expert in that case. I explain here how to quantify the increase in rivals’ costs and the elimination of double marginalization that are caused by a vertical merger and how to evaluate their net effect on downstream customers. I also explain how this economic analysis fits into the three-step burden-shifting approach that the courts apply to mergers under Section 7 of the Clayton Act. Based on my experience in the AT&T/Time Warner case, I identify a number of shortcomings of the 2020 Vertical Merger Guidelines.
Judicial Selection: Ideology versus Character

Introduction 328 I. The Case for Ideology: A Realist Theory of Judicial Selection 331 A. Senator Schumer and the Realist Turn in Judicial Selection 331 B. The Context for the Realist Turn 332 C. A Simple Model of Judicial Attitudes and Dispositions 334 D. Implications of the Model: The Case for Ideological Selection of Judges 337 II. The Case for Character: An Aretaic Theory of Judicial Selection 341 A. The Thin Theory of Judicial Vice 341 B. The Thin Theory of Judicial Virtue 343 C. The Difficulty with Moving Beyond a Thin Theory of Judicial Virtue 343 D. The Virtue of Justice 345 III. The Virtue of Justice as Lawfulness 346 A. Judicial Philosophy as an End Rather than as a Means Only 346 B. Formalism and Justice as Lawfulness 348 C. Fairness versus Lawfulness 350 IV. Objections and Answers 352 A. The Insufficient Evidence Objection 353 B. The Lack of Criteria Objection 354 C. Judicial Virtue and “Personal” Morality 355 D. The Feasibility Objection 355 Conclusion 357
The galactic gamma-ray distribution - Implications for galactic structure and the radial cosmic-ray gradient

The radial distribution of gamma ray emissivity in the Galaxy was derived from flux longitude profiles, using both the final SAS-2 results and the recently corrected COS-B results and analyzing the northern and southern galactic regions separately. The recent CO surveys of the Southern Hemisphere were used in conjunction with the Northern Hemisphere data, to derive the radial distribution of cosmic rays on both sides of the galactic plane. In addition to the 5 kpc ring, there is evidence from the radial asymmetry for spiral features which are consistent with those derived from the distribution of bright H II regions. Positive evidence was also found for a strong increase in the cosmic ray flux in the inner Galaxy, particularly in the 5 kpc region in both halves of the plane. 39 references.
Anomalous electrodynamics and quantum geometry in the Dirac-Harper model for a graphene bilayer

Graphene bilayers with layer antisymmetric strains are studied using the Dirac-Harper model for a pair of single-layer Dirac Hamiltonians coupled by a one-dimensional moir\'e-periodic interlayer tunneling amplitude. This model hosts low-energy, nearly dispersionless bands near charge neutrality that support anomalous polarizations of its charge multipole distributions. These are analyzed introducing a generalized Berry curvature that encodes the field-induced dynamics of multipole fields allowed in a chiral medium with time-reversal symmetry. The formulation identifies a reciprocity relation between responses to layer-symmetric and layer-antisymmetric in-plane electric fields and reveals momentum-space quantum oscillations produced by a spatial pattern of band inversions on the moir\'e scale.
Probabilistic Modeling of Discrete Structural Response with Application to Composite Plate Penetration Models

AbstractDiscrete response of structures often is a key probabilistic quantity of interest. For example, one may need to identify the probability of a binary event, such as whether a structure has b...
FuncADL: Functional Analysis Description Language

The traditional approach in HEP analysis software is to loop over every event and every object via the ROOT framework. This method follows an imperative paradigm, in which the code is tied to the storage format and steps of execution. A more desirable strategy would be to implement a declarative language, such that the storage medium and execution are not included in the abstraction model. This will become increasingly important to managing the large dataset collected by the LHC and the HL-LHC. A new analysis description language (ADL) inspired by functional programming, FuncADL, was developed using Python as a host language. The expressiveness of this language was tested by implementing example analysis tasks designed to benchmark the functionality of ADLs. Many simple selections are expressible in a declarative way with FuncADL, which can be used as an interface to retrieve filtered data. Some limitations were identified, but the design of the language allows for future extensions to add missing features. FuncADL is part of a suite of analysis software tools being developed by the Institute for Research and Innovation in Software for High Energy Physics (IRIS-HEP). These tools will be available to develop highly scalable physics analyses for the LHC.
A Square Equal-Area Map Projection with Low Angular Distortion, Minimal Cusps, and Closed-Form Solutions

A novel square equal-area map projection is proposed. The projection combines closed-form forward and inverse solutions with relatively low angular distortion and minimal cusps, a combination of pr...
Hierarchically Local Tasks and Deep Convolutional Networks

The main success stories of deep learning, starting with ImageNet, depend on convolutional networks, which on certain tasks perform significantly better than traditional shallow classifiers, such as support vector machines. Is there something special about deep convolutional networks that other learning machines do not possess? Recent results in approximation theory have shown that there is an exponential advantage of deep convolutional-like networks in approximating functions with hierarchical locality in their compositional structure. These mathematical results, however, do not say which tasks are expected to have input-output functions with hierarchical locality. Among all the possible hierarchically local tasks in vision, text and speech we explore a few of them experimentally by studying how they are affected by disrupting locality in the input images. We also discuss a taxonomy of tasks ranging from local, to hierarchically local, to global and make predictions about the type of networks required to perform efficiently on these different types of tasks.
Annular modes of variability in the atmospheres of Mars and Titan

Annular modes explain much of the internal variability of Earth’s atmosphere but have never been identified as influential on other planets. Using data assimilation datasets for Mars and a general circulation model for Titan, we demonstrate that annular modes are prominent in the atmospheres of both worlds, capturing a larger fraction of their respective variabilities than Earth’s. One mode describes latitudinal shifts of the jet on Mars, as on Earth, and vertical shifts of the jet on Titan. Another describes pulses of mid-latitude eddy kinetic energy on all three worlds, albeit with somewhat different characteristics. We demonstrate that this latter mode has predictive power for regional dust activity on Mars, revealing its usefulness for understanding Martian weather. The similarity of annular variability in dynamically diverse worlds suggests its ubiquity across the Solar System, potentially extending to exoplanets. Annular (zonally symmetric) atmospheric modes, common on Earth, are found on both Mars and Titan via observations and general circulation models. On Mars, they have considerable impact on dust activity and could be used to predict dust storms. On Titan, they could be linked to sporadic cloud outbursts.
Role of layer thickness and field-effect mobility on photoresponsivity of indium selenide (InSe)-based phototransistors

Understanding and optimizing the properties of photoactive two-dimensional (2D) Van der Waals solids are crucial for developing optoelectronics applications. Here we present a detailed investigation of layer dependent photoconductive behavior of InSe based field-effect transistors (FETs). InSe based FETs with five different channel thickness (t, 20 nm < t < 100 nm) were investigated with a continuous laser source of {\lambda} = 658 nm (1.88 eV) over a wide range of illumination power of 22.8 nW < P < 1.29 {\mu}W. All the devices studied, showed signatures of photogating, however, our investigations suggest that the photoresponsivities are strongly dependent on the thickness of the conductive channel. A correlation between the field-effect mobility ({\mu}FE) values (as a function of channel thickness, t) and photoresponsivity (R) indicates that in general R increases with increasing {\mu}FE (decreasing t) and vice versa. The maximum responsivity of ~ 7.84 A/W and ~ 0.59 A/W was obtained for the device with t = 20 nm and t = 100 nm respectively. These values could substantially increase under the application of a gate voltage. The structure-property correlation-based studies presented here indicate the possibility of tuning the optical properties of InSe based photo-FETs for a variety of applications related to photodetector and/or active layers in solar cells.
Adaptive Group Testing on Networks with Community Structure

Since the inception of the group testing problem in World War II, one of the prevailing assumptions in the probabilistic variant of the problem has been that individuals in the population are infected by a disease independently. However, this assumption rarely holds in practice, as diseases typically spread through interactions between individuals and therefore cause infections to be correlated. Inspired by characteristics of COVID-19 and similar diseases, we consider an infection model over networks which generalizes the traditional i.i.d. model from probabilistic group testing. Under this infection model, we ask whether knowledge of the network structure can be leveraged to perform group testing more efficiently, focusing specifically on community-structured graphs drawn from the stochastic block model. We prove that when the network and infection parameters are conducive to “strong community structure;” our proposed adaptive, graph-aware algorithm outperforms the baseline binary splitting algorithm, and is even order-optimal in certain parameter regimes. A full version of this paper is accessible at http://arxiv.org/abs/2101.0240S. Omitted proofs and numerical experiments are provided in the full version
Extremely correlated superconductors

Abstract Superconductivity in the t - J model is studied by extending the recently introduced extremely correlated fermi liquid theory. Exact equations for the Greens functions are obtained by generalizing Gor’kov’s equations to include extremely strong local repulsion between electrons of opposite spin. These equations are expanded in a parameter λ representing the fraction of double occupancy, and the lowest order equations are further simplified near T c , resulting in an approximate integral equation for the superconducting gap. The condition for T c is studied using a model spectral function embodying a reduced quasiparticle weight Z near half-filling, yielding an approximate analytical formula for T c . This formula is evaluated using parameters representative of single layer High- T c systems. In a narrow range of electron densities that is necessarily separated from the Mott–Hubbard insulator at half filling, we find a typical T c ∼ 1 0 2 K.
Does Gender Matter? The Effect of Management Responses on Reviewing Behavior

The article studies the effect of management responses on the probability of reviewing of female and male reviewers.
A GAN-Like Approach for Physics-Based Imitation Learning and Interactive Control

We present a simple and intuitive approach for interactive control of physically simulated characters. Our work builds upon generative adversarial networks (GAN) and reinforcement learning, and introduces an imitation learning framework where an ensemble of classifiers and an imitation policy are trained in tandem given pre-processed reference clips. The classifiers are trained to discriminate the reference motion from the motion generated by the imitation policy, while the policy is rewarded for fooling the discriminators. Using our GAN-like approach, multiple motor control policies can be trained separately to imitate different behaviors. In runtime, our system can respond to external control signal provided by the user and interactively switch between different policies. Compared to existing method, our proposed approach has the following attractive properties: 1) achieves state-of-the-art imitation performance without manually designing and fine tuning a reward function; 2) directly controls the character without having to track any target reference pose explicitly or implicitly through a phase state; and 3) supports interactive policy switching without requiring any motion generation or motion matching mechanism. We highlight the applicability of our approach in a range of imitation and interactive control tasks, while also demonstrating its ability to withstand external perturbations as well as to recover balance. Overall, our approach has low runtime cost and can be easily integrated into interactive applications and games.
MMF: A loss extension for feature learning in open set recognition

The objective of open set recognition (OSR) is to classify the known classes as well as the unknown classes when the collected samples cannot exhaust all the classes. This paper proposes a loss extension that emphasizes features with larger and smaller magnitudes to find representations that can more effectively separate the known from the unknown classes. Our contributions include: First, we introduce an extension that can be incorporated into different loss functions to find more discriminative representations. Second, we show that the proposed extension can significantly improve the performances of two different types of loss functions on datasets from two different domains. Third, we show that with the proposed extension, one loss function outperforms the others in training time and model accuracy.
Financially constrained mortgage servicers

Abstract Financially constrained mortgage servicers destroyed substantial MBS investor value during the financial crisis through their management of delinquent mortgages. Servicers advance to investors monthly payments missed by borrowers. In order to minimize this obligation to extend financing to distressed borrowers, constrained servicers aggressively pursued foreclosures and modifications at the expense of investors, borrowers, and future mortgage performance. When agency frictions between the servicer and the investor are higher, the servicer’s financial constraints matter more. IV regressions suggest that, on average per defaulted loan, servicers’ financial constraints are responsible for 20% of the total investor value reduction during the financial crisis.
Fighting the Fog: Evaluating the Clarity of Privacy Disclosures in the Age of CCPA

Vagueness and ambiguity in privacy policies threaten the ability of consumers to make informed choices about how businesses collect, use, and share their personal information. The California Consumer Privacy Act (CCPA) of 2018 was intended to provide Californian consumers with more control by mandating that businesses (1) clearly disclose their data practices and (2) provide choices for consumers to opt out of specific data practices. In this work, we explore to what extent CCPA's disclosure requirements, as implemented in actual privacy policies, can help consumers to answer questions about the data practices of businesses. First, we analyzed 95 privacy policies from popular websites; our findings showed that there is considerable variance in how businesses interpret CCPA's definitions. Then, our user survey of 364 Californian consumers showed that this variance affects the ability of users to understand the data practices of businesses. Our results suggest that CCPA's mandates for privacy disclosures, as currently implemented, have not yet yielded the level of clarity they were designed to deliver, due to both vagueness and ambiguity in CCPA itself as well as potential non-compliance by businesses in their privacy policies.
Quantum optics meets black hole thermodynamics via conformal quantum mechanics: II. Thermodynamics of acceleration radiation

The thermodynamics of ``horizon brightened acceleration radiation'' (HBAR), due to a random atomic cloud freely falling into a black hole in a Boulware-like vacuum, is shown to mimic the thermodynamics of the black hole itself. The thermodynamic framework is developed in its most general form via a quantum-optics master equation, including rotating (Kerr) black holes and for any set of initial conditions of the atomic cloud. The HBAR field exhibits thermal behavior at the Hawking temperature and an area-entropy-flux relation that resembles the Bekenstein-Hawking entropy. In addition, this general approach reveals: (i) the existence of an HBAR-black-hole thermodynamic correspondence that explains the HBAR area-entropy-flux relation; (ii) the origin of the field entropy from the near-horizon behavior, via conformal quantum mechanics (CQM).
Parametric Complexity Bounds for Approximating PDEs with Neural Networks

Recent empirical results show that deep networks can approximate solutions to high dimensional PDEs, seemingly escaping the curse of dimensionality. However many open questions remain regarding the theoretical basis for such approximations, including the number of parameters required. In this paper, we investigate the representational power of neural networks for approximating solutions to linear elliptic PDEs with Dirichlet Boundary conditions. We prove that when a PDE's coefficients are representable by small neural networks, the parameters required to approximate its solution scale polynomially with the input dimension $d$ and are proportional to the parameter counts of the coefficient neural networks. Our proof is based on constructing a neural network which simulates gradient descent in an appropriate Hilbert space which converges to the solution of the PDE. Moreover, we bound the size of the neural network needed to represent each iterate in terms of the neural network representing the previous iterate, resulting in a final network whose parameters depend polynomially on $d$ and does not depend on the volume of the domain.
The cost of privacy: Optimal rates of convergence for parameter estimation with differential privacy

Privacy-preserving data analysis is a rising challenge in contemporary statistics, as the privacy guarantees of statistical methods are often achieved at the expense of accuracy. In this paper, we investigate the tradeoff between statistical accuracy and privacy in mean estimation and linear regression, under both the classical low-dimensional and modern high-dimensional settings. A primary focus is to establish minimax optimality for statistical estimation with the (e,δ)-differential privacy constraint. By refining the “tracing adversary” technique for lower bounds in the theoretical computer science literature, we improve existing minimax lower bound for low-dimensional mean estimation and establish new lower bounds for high-dimensional mean estimation and linear regression problems. We also design differentially private algorithms that attain the minimax lower bounds up to logarithmic factors. In particular, for high-dimensional linear regression, a novel private iterative hard thresholding algorithm is proposed. The numerical performance of differentially private algorithms is demonstrated by simulation studies and applications to real data sets.
Into Summarization Techniques for IoT Data Discovery Routing

In this paper, we consider the IoT data discovery problem in very large and growing scale networks. Specifically, we investigate in depth the routing table summarization techniques to support effective and space-efficient IoT data discovery routing. Novel summarization algorithms, including alphabetical based, hash based, and meaning based summarization and their corresponding coding schemes are proposed. The issue of potentially misleading routing due to summarization is also investigated. Subsequently, we analyze the strategy of when to summarize in order to balance the tradeoff between the routing table compression rate and the chance of causing misleading routing. For experimental study, we have collected 100K IoT data streams from various IoT databases as the input dataset. Experimental results show that our summarization solution can reduce the routing table size by 20 to 30 folds with 2-5% increase in latency when compared with similar peer-to-peer discovery routing algorithms without summarization. Also, our approach outperforms DHT based approaches by 2 to 6 folds in terms of latency and traffic.
Spatial dispersion analysis of LGE-CMR for prediction of ventricular arrhythmias in patients with cardiac sarcoidosis.

BACKGROUND Patients with cardiac sarcoidosis (CS) are at increased risk of life-threatening ventricular arrhythmias (VA). Current approaches to risk stratification have limited predictive value. OBJECTIVES To assess the utility of spatial dispersion analysis of late gadolinium enhancement cardiac magnetic resonance (LGE-CMR), as a quantitative measure of myocardial tissue heterogeneity, in risk stratifying patients with CS for VA and death. METHODS Sixty two patients with CS underwent LGE-CMR. LGE images were segmented and dispersion maps of the left and right ventricles were generated as follows. Based on signal intensity (SI), each pixel was categorized as abnormal (SI ≥3SD above the mean), intermediate (SI 1-3 SD above the mean) or normal (SI <1SD above the mean); and each pixel was then assigned a value of 0 to 8 based on the number of adjacent pixels of a different category. Average dispersion score was calculated for each patient. The primary endpoint was VA during follow up. The composite of VA or death was assessed as a secondary endpoint. RESULTS During 4.7 ± 3.5 years of follow up, six patients had VA, and five without documented VA died. Average dispersion score was significantly higher in patients with VA versus those without (0.87 ± 0.08 vs. 0.71 ± 0.16; p = .002) and in patients with events versus those without (0.83 ± 0.08 vs. 0.70 ± 0.16; p = .003). Patients at higher tertiles of dispersion score had a higher incidence of VA (p = .03) and the composite of VA or death (p = .01). CONCLUSIONS Increased substrate heterogeneity, quantified by spatial dispersion analysis of LGE-CMR, may be helpful in risk-stratifying patients with CS for adverse events, including life-threatening arrhythmias.
Seemingly Injective Von Neumann Algebras

We show that a QWEP von Neumann algebra has the weak* positive approximation property if and only if it is seemingly injective in the following sense: there is a factorization of the identity of M $$I{d_M} = vu:M\buildrel u \over \longrightarrow B(H)\buildrel v \over \longrightarrow M$$ with u normal, unital, positive and v completely contractive. As a corollary, if M has a separable predual, M is isomorphic (as a Banach space) to B(l2). For instance this applies (rather surprisingly) to the von Neumann algebra of any free group. Nevertheless, since B(H) fails the approximation property (due to Szankowski) there are M’s (namely B(H)** and certain finite examples defined using ultraproducts) that are not seemingly injective. Moreover, for M to be seemingly injective it suffices to have the above factorization of IdM through B(H) with u, v positive (and u still normal).
Threshold-Based Quantum Optimization

We propose and study Th-QAOA (pronounced Threshold QAOA), a variation of the Quantum Alternating Operator Ansatz (QAOA) that replaces the standard phase separator operator, which encodes the objective function, with a threshold function that returns a value 1 for solutions with an objective value above the threshold and a 0 otherwise. We vary the threshold value to arrive at a quantum optimization algorithm. We focus on a combination with the Grover Mixer operator; the resulting GM-Th-QAOA can be viewed as a generalization of Grover’s quantum search algorithm and its minimum/maximum finding cousin to approximate optimization.Our main findings include: (i) we provide intuitive arguments and show empirically that the optimum parameter values of GM-Th-QAOA (angles and threshold value) can be found with O(log(p) × log M) iterations of the classical outer loop, where p is the number of QAOA rounds and M is an upper bound on the solution value (often the number of vertices or edges in an input graph), thus eliminating the notorious outer-loop parameter finding issue of other QAOA algorithms; (ii) GM-Th-QAOA can be simulated classically with little effort up to 100 qubits through a set of tricks that cut down memory requirements; (iii) somewhat surprisingly, GM-Th-QAOA outperforms non-thresholded GM-QAOA in terms of approximation ratios achieved. This third result holds across a range of optimization problems (MaxCut, Max k-VertexCover, Max k-DensestSubgraph, MaxBisection) and various experimental design parameters, such as different input edge densities and constraint sizes.
Global bifurcation of solitary waves to the Boussinesq abcd system

Abstract The Boussinesq a b c d system arises in the modeling of long wave small amplitude water waves in a channel, where the four parameters ( a , b , c , d ) satisfy one constraint. In this paper we focus on the solitary wave solutions to such a system. In particular we work in two parameter regimes where the system does not admit a Hamiltonian structure (corresponding to b ≠ d ). We prove via analytic global bifurcation techniques the existence of solitary waves in such parameter regimes. Some qualitative properties of the solutions are also derived, from which sharp results can be obtained for the global solution curves. Specifically, we first construct solutions bifurcating from the stationary waves, and obtain a global continuous curve of solutions that exhibits a loss of ellipticity in the limit. The second family of solutions bifurcate from the classical Boussinesq supercritical waves. We show that the curve associated to the second class either undergoes a loss of ellipticity in the limit or becomes arbitrarily close to having a stagnation point.
Confidence Intervals for Nonparametric Empirical Bayes Analysis

In an empirical Bayes analysis, we use data from repeated sampling to imitate inferences made by an oracle Bayesian with extensive knowledge of the data-generating distribution. Existing results pr...
GPA-Tree: Statistical Approach for Functional-Annotation-Tree-Guided Prioritization of GWAS Results.

MOTIVATION In spite of great success of genome-wide association studies (GWAS), multiple challenges still remain. First, complex traits are often associated with many single nucleotide polymorphisms (SNPs), each with small or moderate effect sizes. Second, our understanding of the functional mechanisms through which genetic variants are associated with complex traits is still limited. To address these challenges, we propose GPA-Tree and it simultaneously implements association mapping and identifies key combinations of functional annotations related to risk-associated SNPs by combining a decision tree algorithm with a hierarchical modeling framework. RESULTS First, we implemented simulation studies to evaluate the proposed GPA-Tree method and compared its performance with existing statistical approaches. The results indicate that GPA-Tree outperforms existing statistical approaches in detecting risk-associated SNPs and identifying the true combinations of functional annotations with high accuracy. Second, we applied GPA-Tree to a systemic lupus erythematosus (SLE) GWAS and functional annotation data including GenoSkyline and GenoSkylinePlus. The results from GPA-Tree highlight the dysregulation of blood immune cells, including but not limited to primary B, memory helper T, regulatory T, neutrophils and CD8+ memory T cells in SLE. These results demonstrate that GPA-Tree can be a powerful tool that improves association mapping while facilitating understanding of the underlying genetic architecture of complex traits and potential mechanisms linking risk-associated SNPs with complex traits. AVAILABILITY The GPATree software is available at https://dongjunchung.github.io/GPATree/. SUPPLEMENTARY INFORMATION Supplementary information is available at Bioinformatics online.
The General Problem of Douglas

In contours γ consisting of several closed curves, soap film experi­ments produce multiply connected minimal surfaces, as for example in the classical case of surfaces of revolution of least area. Moreover, for suitable contours γ, soap film experiments indicate the existence of minimal surfaces of higher topological structure such as surfaces not of genus zero or non-orientable surfaces,1 see Figures 4.1 and 4.2. Such more complicated surfaces are formed by the soap film whenever they have greater stability—i. e. smaller area—than simply connected surfaces spanned in the same contour.
American foreign policy in a new era

Introduction 1. Theories of War in an Era of Leading World Peace 2. September 11? How Has It Changed the World? 3. The Confrontation between Iraq and the U.S.: Implications for the Theory and Practice of Deterrence 4. Understanding the Bush Doctrine 5. Where Do We Go from Here?
Medicating children with attention deficit disorder.

To the Editor.— I read the position statement by the American Academy of Pediatrics, Committees on Children With Disabilities and Drugs (Pediatrics 1987;80:758-760) regarding medication for children with attention deficit disorder. It is encouraging that the American Academy of Pediatrics has undertaken to bring this information to its membership; it is disappointing that, in discussing evaluation and treatment, there was no acknowledgment of any role for the child psychiatrist, even though the vast majority of research into diagnosis and treatment has been done by child psychiatrists and published in the psychiatric literature.
Opportunistic Cooperation with Receiver-Based Ratio Combining Strategy

In cooperative wireless communication systems, many combining techniques could be employed at the receiver, such as maximal ratio combining (MRC), equal gain combining (EGC), etc. To address the effect of receiver diversity combining on optimum energy allocation, we analyze the problem of minimizing average total transmit energy under a SNR constraint when different ratio combining methods are utilized at destination. For maximal ratio combining (MRC), based on the explicit analytical solution an asymptotic solution for normalized optimum total energy in terms of μand ?was derived in the high-SNR scenario. For fixed ratio combining (FRC), we find that there does not exist an explicit analytical solution to the optimum energy allocation problem. However, the convexity proof for the energy function provides a way of using numerical convex optimization methods to find the unique solution. Our results also show that, while direct transmission ($\mathcal{E}^*\_r = 0$) is optimum for certain channel states when the destination uses MRC, the relay should always transmit, i.e. $\mathcal{E}^*\_r >0$ for all channel states, when the combining ratio βis a fixed number.
Characterization of a multienzyme complex derived from a Bacillus subtilis DNA-membrane extract that synthesizes RNA and DNA precursors.

The activity of a variety of enzymes involved in the synthesis of RNA and DNA precursors was found to copurify with initiation of DNA replication activity. These enzymes included ribo- and deoxyribonucleoside kinases, kinases for their phosphorylated intermediates, and ribonucleoside diphosphate reductase. This precursor-synthesizing complex is part of a Bacillus subtilis DNA-membrane extract originally shown to contain all of the enzymes and template necessary for initiation of DNA replication (J. Laffan and W. Firshein, J. Bacteriol. 169:2819-2827, 1987). Although the complex incorporated deoxyribonucleoside triphosphates into DNA, deoxyribonucleosides were incorporated even faster, suggesting catalytic facilitation. Both ribonucleosides and deoxyribonucleosides were found by thin-layer chromatography separation to be converted by the complex into their mono-, di-, and triphosphate derivatives. Ribonucleotides were incorporated into DNA via the action of ribonucleoside diphosphate reductase. Some regulatory mechanisms of the kinase system may also be retained by the complex. Electron microscope studies revealed that the precursor-synthesizing-initiation subcomplex is contained within a particulate fraction consisting of different-size vesicles resembling liposomes and that these particles may be structurally important in maintaining the synthetic activity of the subcomplex. Images
Heuristic harvesting of information for case-based argument

The BankXX system models the process of perusing and gathering information for argument as a heuristic best-first search for relevant cases, theories, and other domain-specific information. As BankXX searches its heterogeneous and highly interconnected network of domain knowledge, information is incrementally analyzed and amalgamated into a dozen desirable ingredients for argument (called argument pieces), such as citations to cases, applications of legal theories, and references to prototypical factual scenarios. At the conclusion of the search, BankXX outputs the set of argument pieces filled with harvested material relevant to the input problem situation. This research explores the appropriateness of the search paradigm as a framework for harvesting and mining information needed to make legal arguments. We discuss how we tackled the problem of evaluation of BankXX from both the case-based reasoning (CBR) and task-performance perspectives. In particular, we discuss how various system parameters—start node, evaluation function, resource limit—affected BankXX from the CBR perspective and how well BankXX performs its assigned task of gathering information useful for legal argumentation by running BankXX on real legal cases and comparing its output with the published court opinions for those cases.
Molecular Dynamics Simulation of Ion Channels

Although the biological function of ion channels associated with cells has been clarified, an atomic level understanding of these transmembrane proteins is still lacking. Molecular Dynamics (MD) simulations are a well suited tool to gain insight into the function of such proteins in their host environment. First, we give a brief introduction to the field of ion channels by describing the basic properties, structure, and function of an ion channel. We then present specific results for three a-helical bundles: the synthetic LS2 and LS3 channels, and a shortened sequence of the M2 channel protein associated with the influenza virus.
The Effect of a Mycotoxin Deactivation Product on Growth of Juvenile Rainbow Trout Fed Distillers Dried Grains

AbstractDistillers dried grains (DDG) with solubles (DDGS) is a product that has shown potential as a protein source for some fish species, but high inclusion rates of DDGS have not always been successfully achieved for Rainbow Trout Oncorhynchus mykiss. Our objective was to determine whether inclusion of a mycotoxin deactivation product (Biofix Plus) could improve the ability of high-protein DDG (HPDDG) to replace a portion of the fish meal in diets for Rainbow Trout. The 2 × 2 factorial feeding trial examined protein source (menhaden fish meal [MFM] or HPDDG) with or without Biofix Plus. A control diet (42% digestible protein, 20% crude lipid, 25% MFM) was compared to a test diet in which HPDDG replaced 12% of the total MFM on a digestible-protein basis (24% HPDDG inclusion). Diets were fed to juvenile Rainbow Trout (initial weight: mean ± SE = 30.5 ± 1.6 g) in four replicate tanks per treatment for 9 weeks in a 15°C recirculating system. At the conclusion of the feeding trial, we observed no negative e...
Inverse muon decay, νμ+e→μ−+νe, at the Fermilab Tevatron☆

Abstract We report an improved measurement of the inverse muon decay process, νμ+e→μ−+νe, at the Fermilab Tevatron. The rate of this reaction with respect to the νμ-N charged current interaction is measured to be (0.1245±0.0057(stat.)±0.0031 (sys.)) × 10−2. The measurement confirms the standard model predictions for the Lorentz structure of the weak current, the helicity of the neutrino, and the energy dependence of the cross section.
Paralysis and killing of Caenorhabditis elegans by enteropathogenic Escherichia coli requires the bacterial tryptophanase gene

Pathogenic Escherichia coli, including enteropathogenic E. coli (EPEC), enterohaemorrhagic E. coli (EHEC), enteroinvasive E. coli (EIEC) and enterotoxigenic E. coli (ETEC) are major causes of food and water-borne disease. We have developed a genetically tractable model of pathogenic E. coli virulence based on our observation that these bacteria paralyse and kill the nematode Caenorhabditis elegans. Paralysis and killing of C. elegans by EPEC did not require direct contact, suggesting that a secreted toxin mediates the effect. Virulence against C. elegans required tryptophan and bacterial tryptophanase, the enzyme catalysing the production of indole and other molecules from tryptophan. Thus, lack of tryptophan in growth media or deletion of tryptophanase gene failed to paralyse or kill C. elegans. While known tryptophan metabolites failed to complement an EPEC tryptophanase mutant when presented extracellularly, complementation was achieved with the enzyme itself expressed either within the pathogen or within a cocultured K12 strains. Thus, an unknown metabolite of tryptophanase, derived from EPEC or from commensal non-pathogenic strains, appears to directly or indirectly regulate toxin production within EPEC. EPEC strains containing mutations in the locus of enterocyte effacement (LEE), a pathogenicity island required for virulence in humans, also displayed attenuated capacity to paralyse and kill nematodes. Furthermore, tryptophanase activity was required for full activation of the LEE1 promoter, and for efficient formation of actin-filled membranous protrusions (attaching and effacing lesions) that form on the surface of mammalian epithelial cells following attachment and which depends on LEE genes. Finally, several C. elegans genes, including hif-1 and egl-9, rendered C. elegans less susceptible to EPEC when mutated, suggesting their involvement in mediating toxin effects. Other genes including sek-1, mek-1, mev-1, pgp-1,3 and vhl-1, rendered C. elegans more susceptible to EPEC effects when mutated, suggesting their involvement in protecting the worms. Moreover we have found that C. elegans genes controlling lifespan (daf-2, age-1 and daf-16), also mediate susceptibility to EPEC. Together, these data suggest that this C. elegans/EPEC system will be valuable in elucidating novel factors relevant to human disease that regulate virulence in the pathogen or susceptibility to infection in the host.
“Universal” Frequency Standardization from a Single Frequency Standard†

In this paper a method is described of obtaining from a single frequency standard source (quartz plate oscillator) a very large series of frequencies related to the known frequency by a ratio of simple integers. The frequencies thus attainable range from a few hundred to several millions of cycles per second, covering the entire gamut of audio and radio frequencies now in regular use. Not only does the method provide a means for the calibration of oscillators in this range of frequency, the calibration of wavemeters (or frequency meters) and means for obtaining a desired frequency, or frequencies, for laboratory measurements, but also a means of effecting a direct comparison of frequency standards. The most important result is that such frequency standards may be compared even though they are of widely different frequencies, as for example, it makes possible the comparison of a standard of audio frequency with a standard of radio frequency. The application of the method in laboratory measurements makes it possible to refer all work in which determinations of frequency, or steps of frequency are required directly to a single standard of frequency. Simultaneous comparison of an audio frequency standard, a radio frequency standard, and standing waves on parallel wires is possible.
Democracy, Capitalism, and Income Inequality: Seeking Causal Directions

Recent research shows that lower levels of income inequality cause higher levels of democracy, and vice versa in a simultaneous relationship. A critical factor missing from these studies is a direct exogenous measure of capitalism in models explaining variation in income inequality and democracy. This study examines 50 countries over the years 1978–1993 and finds in a pooled two stage least squares modeling exercise that the Fraser Institute measure of capitalism appears to have a weakly positive linear impact on POLITY IV measures of democracy and a weakly positive linear impact on income inequality (more capitalism, more inequality). There appears to be no higher-order relationship between capitalism and democracy or income inequality, though there is a weak parabolic relationship between democracy and income inequality.
Genetic organization of a repeated DNA sequence family in the rice blast fungus.

Abstract The fungal rice pathogen Magnaporthe grisea contains repetitive DNA sequences called MGR. We have used a DNA probe, MGR586, derived from these sequences and crosses between rice-pathogenic and non-rice-pathogenic laboratory strains of M. grisea to rapidly map genes in this organism. The rice-pathogenic strain contained 57 EcoRI restriction fragments that hybridize to the MGR586 probe; the other five non-rice-pathogenic parent strains contained a single MGR586 sequence. Genetic analysis of MGR segregation detected eight linkage groups and allowed the mapping of three pigmentation genes (Alb1, Rsy1, and Buf1), the mating type locus (Mat1), the nucleolar organizer (Rdn1), the Smol gene, and two restriction fragment length polymorphisms linked to Smol. Our results indicate that the MGR586 loci are randomly distributed about the M. grisea genome and permit the construction of a well-marked linkage map useful for future studies on genome organization and genetic analysis in M. grisea.
Human hematopoietic cell specific nuclear protein MNDA interacts with the multifunctional transcription factor YY1 and stimulates YY1 DNA binding

The human myeloid nuclear differentiation antigen, MNDA, is expressed only in myelomonocytic and a subset of B lymphoid hematopoietic cells. MNDA is uniformly distributed throughout the interphase cell nucleus and associates with chromatin, but does not bind specific DNA sequences. We recently demonstrated that MNDA binds nucleolin and nucleophosmin/NPM/B23 and both of these nuclear proteins bind the ubiquitous zinc finger transcription factor YY1. Investigations of the possible effect of MNDA on the interaction between YY1 and NPM, showed that MNDA bound YY1 directly under both in vitro and in vivo conditions. The MNDA-YY1 interaction enhanced the affinity of YY1 for its target DNA and decreased its rate of dissociation. The N-terminal half (200 amino acids) of MNDA was sufficient for maximum enhancement of YY1 DNA binding and a portion of this sequence was responsible for binding YY1. MNDA participated in a ternary complex with YY1 and the YY1 target DNA element. The results show that MNDA affects the ability of YY1 to bind its target DNA sequnce and that MNDA participates in a ternary complex possibly acting as a cofactor to impart lineage specific features to YY1 function. J. Cell. Biochem. 70:489–506, 1998. © 1998 Wiley-Liss, Inc.
Timed killing kinetic studies of the interaction between ciprofloxacin and β-lactams against gram-negative bacilli

Abstract Timed killing kinetic studies were performed with ciprofloxacin in combination with aztreonam, ceftazidime, piperacillin/tazobactam, and ticarcillin/clavulanic acid against three isolates each of Klebsiella pneumoniae, Enterobacter cloacae, Serratia marcescens , and Pseudomonas aeruginosa . Each antimicrobial agent in the combination was tested at its MIC and at one-half and one-quarter of its MIC. Colony counts were determined at 0, 3, 5, and 7 hours. Synergy occurred most frequently at 7 hours and, when present, was most likely to occur when ciprofloxacin and the β-lactam were tested at concentrations equal to their respective MICs. Synerge after 3 hours of incubation was not predictive of a synergestic interaction at 5 or 7 hours. Antagonism was noted in several instances, particularly when ciprofloxacin and the β-lactam were combined at one-quarter of their respective MICs.