cssi/SciSciGPT-SciSciNet huggingface dataset:
An approximate dual subgradient algorithm for multi-agent non-convex optimization

We consider a multi-agent optimization problem where agents subject to local, intermittent interactions aim to minimize a sum of local objective functions subject to a global inequality constraint and a global state constraint set. In contrast to previous work, we do not require that the objective, constraint functions, and state constraint sets are convex. In order to deal with time-varying network topologies satisfying a standard connectivity assumption, we resort to consensus algorithm techniques and the Lagrangian duality method. We slightly relax the requirement of exact consensus, and propose a distributed approximate dual subgradient algorithm to enable agents to asymptotically converge to a pair of primal-dual solutions to an approximate problem. To guarantee convergence, we assume that the Slater's condition is satisfied and the optimal solution set of the dual limit is singleton. We implement our algorithm over a source localization problem and compare the performance with existing algorithms.
Influence of initial flow direction on the turbulent base pressure in supersonic axisymmetric flow

Turbulent base pressure on conical afterbodies in supersonic axisymmetric flow, including initial direction effect
Comparing the quantification of Förster resonance energy transfer measurement accuracies based on intensity, spectral, and lifetime imaging

The measurement of Forster resonance energy transfer FRET in microscopes can be realized by different imaging modali- ties. In the present work, reference FRET constructs are developed to allow the comparison of FRET microscopy measurements using inten- sity, spectral, and lifetime imaging. Complimentary DNA strands are respectively labeled with Oregon Green 488 OG488 or tetrameth- ylrhodamine TMR. The OG488 dye is fixed at the 5 end of one strand, and the TMR label position is allowed to vary along the com- plimentary strand. Since OG488 and TMR are FRET pairs, the FRET efficiency can be determined theoretically from the distance separat- ing the two dyes of the double-stranded DNA molecules. Microscopic images are formed by imaging microcapillaries containing various mixtures of oligonucleotides labeled with the FRET fluorophore pair, only the donor, or only acceptor. Traditional two-channel intensity measurements are compared with spectrally resolved imaging and fluorescence lifetime imaging by calculating a FRET index. The latter proves to be the best method to quantify FRET efficiency in the image. More importantly, the intensity fraction of molecules undergoing FRET can be quantitatively measured in each pixel of the image. © 2006
Comprehensive defect detection featuring die-to-database reflected light inspection

With ever shrinking k1 lithography, overall reticle quality is paramount to ensure high quality image transfer. State-of-the-art reticle inspection systems play two vital roles in reticle manufacturing: quality assurance and manufacturing process feedback. For quality assurance, the system must be capable of detecting all defects of interest to the end user - defects that repeatedly print on wafer, and also those that may reduce the lithography process window. For process monitoring and improvement, the system must be capable of detecting defects at or near the manufacturing limits of mask manufacturing. In order to meet both needs, an inspection system must detect all defect types including pattern errors and contaminates on all mask surfaces including chrome, quartz, and shifter materials. A new advanced inspection method compares both transmitted and reflected light images to the design database. This comprehensive inspection method detects numerous defects that would be missed in a transmitted or reflected only inspection tool. In this study we have tested a new method for detecting reticle defects. Inspection results will be shown from a programmed defect test vehicle as well as a production reticle.
Next-state functions for finite-state vector quantization

In this paper, the finite-state vector quantization scheme called dynamic finite-state vector quantization (DFSVQ) is investigated with regard to its subcodebook construction. In DFSVQ, each input block is encoded by a small codebook called subcodehook which is created from a much larger codebook called supercodebook. Each subcodebook is constructed by selecting, using a reordering procedure, a set of appropriate codevectors from the supercodebook. The performance of the DFSVQ depends on this reordering procedure; therefore, several reordering procedures are introduced and their performances are evaluated in this paper. The reordering procedures that are investigated, are based on the conditional histogram of the codevectors, index prediction, vector prediction, nearest neighbor design, and frequency usage of the code-vectors. The performances of the reordering procedures are evaluated by comparing their hit ratios (the number of blocks encoded by the subcodebook) and their computational complexity. Experimental results are presented and it is found that the reordering procedure based on the vector prediction performs the best when compared with the other reordering procedures.
Search for right-handed currents in muon decay

We report new limits on right-handed currents, based on precise measurements of the endpoint of the e+ spectrum fromμ + decay. Highly polarizedμ + from the TRIUMF “surface” beam were stopped in pure metal foils within either an 1.1-T spin-holding logitudinal field, or a 70-gauss spin-precessing transverse field. Decay e+ emitted within 200 mrad of the beam direction were momentum-analyzed to ±0.2%. For the spin-held data, decay via (V-A) currents requires the e+ rate to approach zero in the beam direction at the endpoint. Measurement of this rate sets the 90%-confidence limits ξP μδ/ϱ>0.9959 and M(WR)>380 GeV, where WR is the possible right-handed gauge boson. For the spin-precessed data we independently determine a 90% confidence limit ξP μδ/ϱ>0.9918.
Cation exchange on the nanoscale: an emerging technique for new material synthesis, device fabrication, and chemical sensing

Cation exchange is an age-old technique for the chemical conversion of liquids or extended solids by place-exchanging the cations in an ionic material with a different set of cations. The technique is undergoing a major revival with the advent of high-quality nanocrystals: researchers are now able to overcome the limitations in bulk systems and fully exploit cation exchange for materials synthesis and discovery via rapid, low-temperature transformations in the solid state. In this tutorial review, we discuss cation exchange as a promising materials synthesis and discovery tool. Exchange on the nanoscale exhibits some unique attributes: rapid kinetics at room temperature (orders of magnitude faster than in the bulk) and the tuning of reactivity via control of nanocrystal size, shape, and surface faceting. These features make cation exchange a convenient tool for accessing nanocrystal compositions and morphologies for which conventional synthesis may not be established. A simple exchange reaction allows extension of nanochemistry to a larger part of the periodic table, beyond the typical gamut of II-VI, IV-VI, and III-V materials. Cation exchange transformations in nanocrystals can be topotactic and size- and shape-conserving, allowing nanocrystals synthesized by conventional methods to be used as templates for production of compositionally novel, multicomponent, or doped nanocrystals. Since phases and compositions resulting from an exchange reaction can be kinetically controlled, rather than governed by the phase diagram, nanocrystals of metastable and hitherto inaccessible compositions are attainable. Outside of materials synthesis, applications for cation exchange exist in water purification, chemical staining, and sensing. Since nanoscale cation exchange occurs rapidly at room temperature, it can be integrated with sensitive environments such as those in biological systems. Cation exchange is already allowing access to a variety of new materials and processes. With better mechanistic understanding and control, researchers may be able to advance the field to a stage where a custom nanostructure of arbitrary complexity would be achievable by simple cation exchange chemistry and a basic understanding of the periodic table.
On Decompositions of the KdV 2-Soliton

The KdV equation is the canonical example of an integrable nonlinear partial differential equation supporting multisoliton solutions. Seeking to understand the nature of this interaction, we investigate different ways to write the KdV 2-soliton solution as a sum of two or more functions. The paper reviews previous work of this nature and introduces new decompositions with unique features, putting it all in context and in a common notation for ease of comparison.
The Immensely Inflated News Audience: Assessing Bias in Self-Reported News Exposure

Many studies of media effects use self-reported news expo- sure as their key independent variable without establishing its validity. Motivated by anecdotal evidence that people's reports of their own me- dia use can differ considerably from independent assessments, this study examines systematically the accuracy of survey-based self-reports of news exposure. I compare survey estimates to Nielsen estimates, which do not rely on self-reports. Results show severe overreporting of news exposure. Survey estimates of network news exposure follow trends in Nielsen ratings relatively well, but exaggerate exposure by a factor of 3 on average and as much as eightfold for some demographics. It follows that apparent media effects may arise not because of differences in ex- posure, but because of unknown differences in the accuracy of reporting exposure.
Methods for Compensating for Control Allocator and Actuator Interactions

In this work, a method, which post-processes the output of a control allocation algorithm, is developed to compensate for actuator dynamics. In reaching this objective, it is of great importance to consider the real-world applicability of the approach. In order to obtain an algorithm which can operate in real-time on a typical ∞ight computer, it is pertinent to not add to the complexity of the constrained control allocation algorithm. Likewise, it is necessary to develop an approach that is applicable to both the saturated and unsaturated control efiector cases. One method which can accomplish these goals is to post-process the output of the control allocation algorithm to overdrive the actuators so that at the end of a sampling interval, the actual actuator positions are equivalent to the desired actuator positions. This is the approach taken in this work and it yields a simple, but efiective, means of compensating for actuator dynamics.
Comments on ‘Canonical transformation for a class of time-varying multivariable systems’

(1987). Comments on ‘Canonical transformation for a class of time-varying multivariable systems’. International Journal of Control: Vol. 45, No. 1, pp. 363-363.
The bestest little Higgs

While little Higgs models provide an interesting way to address the hierarchy problem, concrete models in the literature typically face two major obstacles. First, the mechanism for generating a Higgs quartic coupling often leads to large violations of custodial symmetry. Second, there is a tension between precision electroweak observables in the gauge sector and fine-tuning in the top sector. In this work, we present a new little Higgs model which solves both of these problems. The model is based on an SO(6) × SO(6)/SO(6) coset space which has custodial symmetry built in. The Higgs quartic coupling takes a particularly simple form and does not suffer from the “dangerous singlet” pathology. We introduce a gauge breaking module which decouples the mass of gauge partners from the mass of top partners, allowing for natural electroweak symmetry breaking. The collider phenomenology is dominated by production and decay of the top partners, which are considerably lighter than in traditional little Higgs theories.
A Ceramic Photonic Crystal Temperature Sensor

Photonic bandgap effects are observed in a disordered array of sol-gel-derived SiO2 particles prepared via centrifugation of a colloidal suspension. Tunability in the optical response is achieved by infiltrating an organic liquid (1-methylnaphthalene) that possesses a moderately high temperature coefficient of refractive index (dn/dT) into the interparticle void space. The varying dn/dT value between SiO2 and 1-methylnaphthalene is used to tune the contrast ratio, relative to temperature. The resulting optical temperature sensor is the first adaptive ceramic photonic crystal of its type, to our knowledge, and provides a proof-of-concept for simple, disposable optical devices that are based on photonic band engineering. Novel applications of optical structures that possess short-range particulate order are discussed, in consideration of the direct analogy between photonic bandgaps and X-ray diffraction.
Sex Disparities in Arrest Outcomes for Domestic Violence

Domestic violence arrests have been historically focused on protecting women and children from abusive men. Arrest patterns continue to reflect this bias with more men arrested for domestic violence compared to women. Such potential gender variations in arrest patterns pave the way to the investigation of disparities by sex of the offender in domestic violence arrests. This study utilizes data from a quantitative dataset that includes responses by police officers who completed a specially mandated checklist after responding to a domestic dispute. The results showed that while females are arrested quite often in domestic disputes, there remains a significant difference in the arrest outcome whereby male suspects were more likely to be arrested than female suspects. Regression models further indicated differences based on sex and certain predictors of arrest, which supported sex-based rationales in arrests for domestic violence.
A new street connectivity indicator to predict performance for feeder transit services

This paper defines a novel street Connectivity Indicator (C.I.) to predict transit performance by identifying the role that street network connectivity plays in influencing the service quality of demand responsive feeder transit services. This new C.I. definition is dependent upon the expected shortest path between any two nodes in the network, includes spatial features and transit demand distribution information and is easy to calculate for any given service area. Simulation analyses over a range of networks have been conducted to validate the new definition. Results show a desirable monotonic relationship between transit performance and the proposed C.I., whose values are directly proportional and therefore good predictors of the transit performance, outperforming other available indicators, typically used by planners.
Brain Drain in Rural America

The paper aims at understanding changes in the distribution and accumulation of intellectual capital by analyzing migrants' educational profiles across a sample of 303 U.S. counties. The results suggest that newcomers are better educated than the resident population, and the education gap is most pronounced for newcomers from other states. The results further suggest that the educational status of newcomers "in-migrants" is positively related to the educational status of the resident population "stayers", thus implying a further agglomeration of human capital across space. However, for interstate migrants the effect is context-dependent, playing a greater role in urban than in rural settings.
Decentralized two-sided sequential tests for A normal mean

This article is concerned with decentralized sequential testing of a normal mean µ with two-sided alternatives. It is assumed that in a single-sensor network system with limited local memory, i.i.d. normal raw observations are observed at the local sensor, and quantized into binary messages that are sent to the fusion center, which makes a final decision between the null hypothesis H 0 : µ = 0 and the alternative hypothesis H 1 : µ = ±1. We propose a decentralized sequential test using the idea of tandem quantizers (or equivalently, a one-shot feedback). Surprisingly, our proposed test only uses the quantizers of the form I(X n ≥λ), but it is shown to be asymptotically Bayes. Moreover, by adopting the principle of invariance, we also investigate decentralized invariant tests with the stationary quantizers of the form I(|X n | ≫ λ), and show that λ = 0.5 only leads to a suboptimal decentralized invariant sequential test. Numerical simulations are conducted to support our arguments.
Permutation patterns and statistics

Abstract Let S n denote the symmetric group of all permutations of { 1 , 2 , … , n } and let S = ∪ n ≥ 0 S n . If Π ⊆ S is a set of permutations, then we let Av n ( Π ) be the set of permutations in S n which avoid every permutation of Π in the sense of pattern avoidance. One of the celebrated notions in pattern theory is that of Wilf-equivalence, where Π and Π ′ are Wilf equivalent if # Av n ( Π ) = # Av n ( Π ′ ) for all n ≥ 0 . In a recent paper, Sagan and Savage proposed studying a q -analogue of this concept defined as follows. Suppose st : S → { 0 , 1 , 2 , … } is a permutation statistic and consider the corresponding generating function F n st ( Π ; q ) = ∑ σ ∈ Av n ( Π ) q st σ . Call Π , Π ′ st-Wilf equivalent if F n st ( Π ; q ) = F n st ( Π ′ ; q ) for all n ≥ 0 . We present the first in-depth study of this concept for the inv and maj statistics. In particular, we determine all inv - and maj -Wilf equivalences for any Π ⊆ S 3 . This leads us to consider various q -analogues of the Catalan numbers, Fibonacci numbers, triangular numbers, and powers of two. Our proof techniques use lattice paths, integer partitions, and Foata’s second fundamental bijection. We also answer a question about Mahonian pairs raised in the Sagan–Savage article.
CONTINUOUS HOMOTOPY FIXED POINTS FOR LUBIN-TATE SPECTRA

We provide a new and conceptually simplified construction of continuous homotopy fixed point spectra for Lubin-Tate spectra under the action of the extended Morava stabilizer group. Moreover, our new construction of a homotopy fixed point spectral sequence converging to the homotopy groups of the homotopy fixed points of Lubin-Tate spectra is isomorphic to an Adams spectral sequence converging to the homotopy groups of the spectra constructed by Devinatz and Hopkins. The new idea is built on the theory of profinite spectra with a continuous action by a profinite group.
The Higgs Boson: What do we know?

Summary form only given. Lists abstracts and author biographies for the conference Keynote Lectures.
Enantioselective Synthesis of 1,5-anti- and 1,5-syn-Diols Using a Highly Diastereoselective One-Pot Double Allylboration Reaction Sequence

Highly diastereo- and enantioselective syntheses of 1,5-disubstituted (E)-1,5-anti-pent-2-endiols 1 and (Z)-1,5-syn-pent-2-endiols 2 have been achieved via the one-pot coupling of two different aldehydes with either (E)-γ-(1,3,2-dioxaborinanyl)-allyl]diisopinocampheylborane (4) or (E)-γ-(4,4,5,5-tetraphenyl-1,3,2-dioxaborolanyl)allyl]diisopinocampheylborane (11), respectively. The indicated diols 1 and 2 are obtained in 63−95% yield with 89−96% ee and ≥20:1 diastereoselectivity in all cases. The bifunctional γ-boryl-substituted allylborane reagents 4 and 11 were generated in situ by the hydroboration of allenes 3 and 10 with diisopinocampheylborane. The keys to the success of this method are the excellent stereocontrol in the allylboration step leading to 5 and the corresponding substituted methallylboronate derived from 11, the stereospecificity of the subsequent allylboration reaction of the substituted methallylboronate intermediates, and the ability of the diol auxiliary to induce equatorial or axial ...
Efficient palladium-catalyzed nucleophilic addition of triorganoindium reagents to carbocyclic derivatives.

Palladium (0)-catalyzed allylic substitution reactions employing triorganoindium reagents have been investigated. In situ generated vinyl- and arylindiums react with substituted and unsubstituted cyclohex-2-enyl esters in the presence of 1−3 mol % Pd2(dba)3 to produce vinyl- or arylcyclohexenes in moderate to excellent yields. The stereoselectivity of this process was also examined, and evidence is presented that the reaction proceeds with inversion of stereochemical configuration.
Sensor array calibration via tracking with the extended Kalman filter

Starting with a randomly distributed sensor array with unknown sensor orientations, array calibration is needed before target localization and tracking can be performed using classical triangulation methods. In this paper, we assume that the sensors are only capable of accurate direction of arrival (DOA) estimation. The calibration problem cannot be completely solved given the DOA estimates alone, since the problem is not only rotationally symmetric but also includes a range ambiguity. Our approach to calibration is based on tracking a single target moving at a constant velocity. In this case, the sensor array can be calibrated from target tracks generated by an extended Kalman filter (EKF) at each sensor. A simple algorithm based on geometrical matching of similar triangles will align the separate tracks and determine the sensor positions and orientations relative to a reference sensor. Computer simulations show that the algorithm performs well even with noisy DOA estimates at sensors.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Formal Synthesis of Leucascandrolide A

Extracts from the calcareous sponge Leucascandra caveolata were collected from waters along the northeastern coast of New Caledonia by Pietra and co-workers, and yielded the novel marine macrolide leucascandrolide A (1). The structure of 1 was elucidated by extensive 2D NMR experiments and analysis of Mosher ester derivatives, which revealed an 18-membered macrolide containing two bridging trisubstituted tetrahydropyran rings and an ester side chain with a Za,b-unsaturated oxazole. The natural product displayed significant in vitro cytotoxicity against both KB oral epidermoid carcinoma and P388 leukemia cell lines (IC50= 0.05 and 0.25 mgmL , respectively), as well as antifungal activity against the pathogenic yeast Candida albicans. Attempts to isolate additional quantities of the natural product through subsequent harvesting of sponge samples proved unfruitful, which led to the suggestion that 1 may be derived from the
Effects of using observers on stabilization of uncertain linear systems

The effects of observers on robust linear feedback controllers are studied. Sufficient conditions are obtained that guarantee full recovery of the allowable uncertainty bounds attainable by full state feedback. The effects of the resulting high gain observers on the disturbance rejection bounds are also studied. It is shown that full recovery of the uncertainty bound leads to possible large degradation in disturbance rejection. However, if there is only additive plant disturbance and no measurement disturbance, this degradation can be prevented. >
Preparation and chemistry of phosphoranyl-derived iodanes.

The preparation and chemistry of novel phosphoranyl-derived λ3-iodanes is reported. The phosphoranyl-derived phenyliodonium sulfonates were prepared in good yields by the reaction of stabilized phosphonium ylides [1-triphenylphosphoranylidene-2-propanone, methyl(triphenylphosphoranylidene)acetate, (triphenylphosphoranylidene)acetaldehyde, and (triphenylphosphoranylidene)acetonitrile] with the pyridinium complex of iodobenzene ditriflate or with [hydroxy(tosyloxy)iodo]benzene under mild conditions. These compounds represent a potentially useful class of reagents that combine in one molecule synthetic advantages of a phosphonium ylide and an iodonium salt. Specifically, phosphorane-derived phenyliodonium tosylates can react with soft nucleophiles, such as iodide, bromide, benzenesulfinate, and thiophenolate anions, with a selective formation of the respective α-functionalized phosphonium ylides, which can be further converted to alkenes by the Wittig reaction with benzaldehyde. The phosphoranyl-derived benz...
Scramjet Inlet Control by Off-Body Energy Addition: A Virtual Cowl

The theory of energy addition to hypersonic airflow off the vehicle to increase air mass capture and reduce spillage in scramjet inlets at Mach numbers below the design value is explored. The heated region creates a virtual cowl and deflects flow streamlines into the inlet. Optimization studies are performed with a two-dimensional inviscid fluid code. The best location of the energy addition region is near the intersection of the nose shock of the vehicle with the continuation of the cowl line, and slightly below that line. In that case, the shock generated by the heating is close to the shock that is a reflection of the vehicle nose shock off the imaginary solid surface-extension of the cowl. Effects of the size and shape of the energy addition region on inlet performance are also studied.
Localization Theorems for Nonlinear Eigenvalue Problems

Let $T : \Omega \rightarrow \mathbb{C}^{n \times n}$ be a matrix-valued function that is analytic on some simply connected domain $\Omega \subset \mathbb{C}$. A point $\lambda \in \Omega$ is an eig...
Construction of Preferences by Constraint Satisfaction

Participants were given a choice between two multiattribute alternatives (job offers). Preferences for the attributes were measured before, during, and after the choices were made. We found that over the course of decision making, the preferences shifted to cohere with the choice: The attributes of the option that was eventually chosen came to be rated more favorably than they had been rated initially, while the attributes of the rejected option received lower preference ratings than before. These coherence shifts were triggered by a single attribute that decisively favored one option (Experiment 1), and occurred spontaneously in the absence of a decisive attribute (Experiment 2). The coherence shift preceded commitment to choice. These findings favor constraint-satisfaction models of decision making.
Velocity filters for multiple interferences in two-dimensional geophysical data

A procedure for the velocity filtering of two-dimensional geophysical data is discussed. This procedure involves repeatedly applying multichannel filters to a small number of overlapping subarrays of the input data. The multichannel filters can be chosen so that the resulting velocity filter is capable of suppressing multiple interferences traveling at different velocities. The two-dimensional frequency-wavenumber expression of the velocity filter is derived. With this expression, it becomes possible to implement the filter using two-dimensional fast Fourier transform (FFT) techniques. Two examples which illustrate the performance of the derived filters are presented. >
Logic programming for finding models in the logics of knowledge and its applications: A case study

The logics of knowledge are modal logics that have been shown to be effective in representing and reasoning about knowledge in multi-agent domains. Relatively few computational frameworks for dealing with computation of models and useful transformations in logics of knowledge (e.g., to support multi-agent planning with knowledge actions and degrees of visibility) have been proposed. This paper explores the use of logic programming (LP) to encode interesting forms of logics of knowledge and compute Kripke models. The LP modeling is expanded with useful operators on Kripke structures, to support multi-agent planning in the presence of both world-altering and knowledge actions. This results in the first ever implementation of a planner for this type of complex multi-agent domains.
Auditors' Reactions to Inconsistencies between Financial and Nonfinancial Measures: The Interactive Effects of Fraud Risk Assessment and a Decision Prompt

ABSTRACT: Nonfinancial measures (NFMs), such as employee headcount and production space, are operational measures that are not included on the face of the financial statements but are often disclosed elsewhere in the annual report or 10-K (e.g., in Management's Discussion and Analysis). Professional standards, auditing texts, and prior research suggest that external auditors can use NFMs to verify their clients' reported financial information and, in turn, improve audit quality. In an initial experiment where auditors develop an expectation for a client's sales balance, they generally fail to identify a seeded inconsistency between the client's sales and related NFMs. In our second experiment, where we introduce an NFM prompt and manipulate fraud risk as high and low, auditors are more likely to react to the inconsistency (i.e., rely more on inconsistent NFMs/develop expectations that reflect the client's current year decline in NFMs) when they are specifically prompted to consider the implications of NFM...
Engineers versus managers: experts, market-making and state-building in Putin's Russia

Market-making and state-building are mutually reinforcing processes. This paper documents the role played in these processes by two groups of experts in Russia’s electricity sector: technical experts and managerially trained experts. I develop two arguments: (1) a shift in the relative power positions of these two groups was a constitutive element of the marketization and liberalization of the electricity sector. The victory of the managerial experts made assets legible and therefore ‘value-able’. (2) the paper demonstrates that the promotion of managerial experts at the expense of technical experts was a deeply political transformation, as it involved the replacement of a well-established, well-connected group of incumbent political actors. More specifically, I show how the promotion of managerial experts at the expense of technical experts helped the federal government of President Putin eliminate one of the main challengers to its ability to regulate economic activity from the centre ! regional governors.
Computation in a single Neuron: Hodgkin and Huxley revisited

A spiking neuron "computes" by transforming a complex dynamical input into a train of action potentials, or spikes. The computation performed by the neuron can be formulated as dimensional reduction, or feature detection, followed by a nonlinear decision function over the low-dimensional space. Generalizations of the reverse correlation technique with white noise input provide a numerical strategy for extracting the relevant low-dimensional features from experimental data, and information theory can be used to evaluate the quality of the low-dimensional approximation. We apply these methods to analyze the simplest biophysically realistic model neuron, the Hodgkin-Huxley (HH) model, using this system to illustrate the general methodological issues. We focus on the features in the stimulus that trigger a spike, explicitly eliminating the effects of interactions between spikes. One can approximate this triggering "feature space" as a two-dimensional linear subspace in the high-dimensional space of input histories, capturing in this way a substantial fraction of the mutual information between inputs and spike time. We find that an even better approximation, however, is to describe the relevant subspace as two dimensional but curved; in this way, we can capture 90% of the mutual information even at high time resolution. Our analysis provides a new understanding of the computational properties of the HH model. While it is common to approximate neural behavior as "integrate and fire," the HH model is not an integrator nor is it well described by a single threshold.
Computational Aerothermodynamics in Aeroassist Applications

Aeroassisted planetary entry uses atmospheric drag to decelerate spacecraft from super-orbital to orbital or sub- orbital velocities. Numerical simulation of flow fields surrounding these spacecraft during hypersonic atmospheric entry is required to define aerothermal loads. The severe compression in the shock layer in front of the vehicle and subsequent, rapid expansion into the wake are characterized by high temperature, thermo-chemical nonequilibrium processes. Implicit algorithms required for efficient, stable computation of the governing equations involving disparate time scales of convection, diffusion, chemical reactions, and thermal relaxation are discussed. Robust point-implicit strategies are utilized in the initialization phase; less robust but more efficient line-implicit strategies are applied in the endgame. Applications to ballutes (balloon-like decelerators) in the atmospheres of Venus, Mars, Titan, Saturn, and Neptune and a Mars Sample Return Orbiter (MSRO) are featured. Examples are discussed where time-accurate simulation is required to achieve a steady-state solution.
Towards an Analysis of How Shared Representations Are Manipulated to Mediate Online Synchronous Collaboration

This work is concerned with an analysis of how shared representations – notations that are manipulated by more than one person during a collaborative task – are used as resources to support that collaboration. The analysis is built on the concept of “informational uptake”: how information moves and is transformed between individuals via a graphical representation as well as a verbal “chat” tool. By examining patterns of such uptake, one can see ways in which the activity of two individuals is coupled and joined into a larger cognitive (and sometimes knowledge-building) activity distributed across the persons and representations they are manipulating.
Addressing genetic tumor heterogeneity through computationally predictive combination therapy

Recent tumor sequencing data suggests an urgent need to develop a methodology to directly address intra-tumor heterogeneity in the design of anti-cancer treatment regimens. We use RNA interference to model heterogeneous tumors, and demonstrate successful validation of computational predictions for how optimized drug combinations can yield superior effects on these tumors both in vitro and in vivo. Importantly, we discover here that for many such tumors knowledge of the predominant subpopulation is insufficient for determining the best drug combination. Surprisingly, in some cases the optimal drug combination does not include drugs that would treat any particular subpopulation most effectively, challenging straightforward intuition. We confirm examples of such a case with survival studies in a murine pre-clinical lymphoma model. Altogether, our approach provides new insights concerning design principles for combination therapy in the context of intratumoral diversity, data that should inform the development of drug regimens superior for complex tumors.
Multiwall Carbon Nanotubes: Synthesis and Application

Chemical vapor deposition (CVD) is the most promising synthesis route for economically producing large quantities of carbon nanotubes. We have developed a low-cost CVD process for the continuous production of aligned multiwall carbon nanotubes (MWNTs). Here we report the effects of reactor temperature, reaction time, and carbon partial pressure on the yield, purity, and size of the MWNTs produced. A simple method for purifying and healing structural defects in the nanotubes is described. The dispersion of nanotubes in polymer matrices has been investigated as a means of deriving new and advanced engineering materials. These composite materials have been formed into fibers and thin films and their mechanical and electrical properties determined.
Semiflexible filament networks viewed as fluctuating beam-frames

We present a new method combining structural and statistical mechanics to study the entropic elasticity of semiflexible filament networks. We view a filament network as a frame structure and use structural mechanics to determine its static equilibrium configuration under applied loads in the first step. To account for thermal motion around this static equilibrium state, we then approximate the potential energy of the deformed frame structure up to the second order in kinematic variables and obtain a deformation-dependent stiffness matrix characterizing the flexibility of the network. Using statistical mechanics, we then evaluate the partition function, free energy and thermo-mechanical properties of the network in terms of the stiffness matrix. We show that penalty methods commonly used in finite elements to account for constraints, are applicable even when statistical and structural mechanics are combined in our method. We apply our framework to understand the expansion, shear, uniaxial tension and compression behavior of some simple filament networks. We are able to capture the stress-stiffening behavior due to filament reorientation and stretching out of thermal fluctuations, as well as the reversible stress-softening behavior due to filament buckling. Finally, we apply our method to square networks and show how their mechanical behavior is different from triangular networks with similar filament density and persistence length.
Kalman filtered Compressed Sensing

We consider the problem of reconstructing time sequences of spatially sparse signals (with unknown and time-varying sparsity patterns) from a limited number of linear "incoherent" measurements, in real-time. The signals are sparse in some transform domain referred to as the sparsity basis. For a single spatial signal, the solution is provided by Compressed Sensing (CS). The question that we address is, for a sequence of sparse signals, can we do better than CS, if (a) the sparsity pattern of the signal's transform coefficients' vector changes slowly over time, and (b) a simple prior model on the temporal dynamics of its current non-zero elements is available. The overall idea of our solution is to use CS to estimate the support set of the initial signal's transform vector. At future times, run a reduced order Kalman filter with the currently estimated support and estimate new additions to the support set by applying CS to the Kalman innovations or filtering error (whenever it is "large").
Instant nonthermal leptogenesis

We propose an economical model of nonthermal leptogenesis following inflation during instant preheating. The model involves only the inflaton field, the standard model Higgs, and the heavy ``right-handed'' neutrino.
Is the FHA Creating Sustainable Homeownership

We produce first estimates of the sustainability of homeownership for recent Federal Housing Administration (FHA) borrowers. Unfortunately, the FHA does not produce its own statistics on sustainability. Neither does it permit researchers access to its data on internal refinances. This imposes significant barriers to entry for researchers who wish to track FHA borrower performance over time. We carefully construct the required tracking data to overcome this barrier. We forecast that no more than 75% of the 2007–2009 vintages of FHA borrowers will be able to successfully exit the FHA system. Our work raises questions about FHA's role, its accounting and its accountability.
When is external debt sustainable

The article empirically examines the determinants of debt distress, defined as periods in which countries resort to any of three forms of exceptional finance: significant arrears on external debt, Paris Club rescheduling, and non-concessional International Monetary Fund lending. Probit regressions show that three factors explain a substantial fraction of the cross-country and time-series variation in the incidence of debt distress: the debt burden, the quality of policies and institutions, and shocks. The relative importance of these factors varies with the level of development. These results are robust to a variety of alternative specifications, and the core specifications have substantial out-of-sample predictive power. The quantitative implications of these results are examined for the lending strategies of official creditors.
Passive devices for determining fracture strength of MEMS structural materials

In microelectromechanical systems (MEMS) device design and fabrication there exists a need for quick determination of fracture strength. This report describes several passive devices that use the residual stresses contained within structural MEMS materials to determine fracture strength. Stress concentrations of varying degrees are generated at micromachined notch roots, and the critical stress required for failure indicates the fracture strength. A variety of devices have been fabricated from materials, such as polysilicon, silicon nitride, and aluminum, with widely varying residual stresses, including both tensile and compressive.
Wouthuysen-Field coupling strength and application to high-redshift 21-cm radiation

The first ultraviolet sources in the universe are expected to have coupled the H I spin temperature to the gas kinetic temperature via scattering in the Lyα resonance (the 'Wouthuysen-Field effect'). By establishing an Hi spin temperature different from the temperature of the cosmic microwave background, the Wouthuysen-Field effect should allow observations of H I during the reionization epoch in the redshifted 21-cm hyperfine line. This paper investigates four mechanisms that can affect the strength of the Wouthuysen-Field effect that were not previously considered. (1) Photons redshifting into the Hi Lyman resonances may excite an H atom and result in a radiative cascade terminating in two-photon 2s 1/2 → 1s 1/2 emission, rather than always degrading to Lyα as usually assumed. (2) The fine structure of the Lyα resonance alters the photon frequency distribution and leads to a suppression of the scattering rate. (3) The spin-flip scatterings change the frequency of the photon and cause the photon spectrum to relax not to the kinetic temperature of the gas but to a temperature between the kinetic and spin temperatures, effectively reducing the strength of the Wouthuysen-Field coupling. (4) Near line centre, a photon can change its frequency by several times the line width in a single scattering event, thus potentially invalidating the usual calculation of the Lyα spectral distortion based on the diffusion approximation. It is shown that (1) suppresses the Wouthuysen-Field coupling strength by a factor of up to ∼2, while (2) and (3) are important only at low kinetic temperatures. Effect (4) has a ≤3 per cent effect for kinetic temperatures T k ≥ 2 K. In particular, if the pre-reionization intergalactic medium was efficiently heated by X-rays, only effect (1) is important. Fitting formulae for the Wouthuysen-Field coupling strength are provided for the range of T k ≥ 2 K and Gunn-Peterson optical depth 10 5 < TOP < 10 7 so that all of these effects can be easily incorporated into 21-cm codes.
The Experience of Conditional Cash Transfers in Latin America and the Caribbean

This article discusses the experience of six conditional cash transfer programmes in Latin America, a model of social safety-nets which has grown to dominate the social protection sector in the region during the past decade. While they have been generally successful in terms of achieving their core objective, it is still not clear whether these programmes constitute the most cost-efficient or sustainable solution to the development bottleneck they seek to address. Furthermore, the almost exclusive focus on the human capital accumulation of children leads to missed opportunties in terms of impact on household welfare and the broader rural development context.
PDM: A knowledge-based tool for model construction

Abstract This paper describes PDM, a knowledge-based tool designed to help non-expert users construct Linear Programming (LP) models of Production, Distribution and Inventory (PDI) planning problems. PDM interactively aids users in defining a qualitative model of their planning problem, and employs it to generate problem-specific inferences and as input to a model building component that mechanically constructs the algebraic schema of the appropriate LP model. Interesting features of PDM include the application of domain knowledge to guide user interaction, the use of syntactic knowledge of the problem representation language to effect model revision, and in the use of a small set of primitive modeling rules in model construction.
Reliable Facility Location Design Under the Risk of Disruptions

Reliable facility location models consider unexpected failures with site-dependent probabilities, as well as possible customer reassignment. This paper proposes a compact mixed integer program (MIP) formulation and a continuum approximation (CA) model to study the reliable uncapacitated fixed charge location problem (RUFL), which seeks to minimize initial setup costs and expected transportation costs in normal and failure scenarios. The MIP determines the optimal facility locations as well as the optimal customer assignments and is solved using a custom-designed Lagrangian relaxation (LR) algorithm. The CA model predicts the total system cost without details about facility locations and customer assignments, and it provides a fast heuristic to find near-optimum solutions. Our computational results show that the LR algorithm is efficient for mid-sized RUFL problems and that the CA solutions are close to optimal in most of the test instances. For large-scale problems, the CA method is a good alternative to the LR algorithm that avoids prohibitively long running times.
Attaining Potentially Good Reduction in Arithmetic Dynamics

Let K be a non-archimedean field, and let φ ∈ K(z) be a rational function of degree d ≥ 2. If φ has potentially good reduction, we give an upper bound, depending only on d, for the minimal degree of an extension L/K such that φ is conjugate over L to a map of good reduction. In particular, if d = 2 or d is less than the residue characteristic of K, the bound is d + 1. If K is discretely valued, we give examples to show that our bound is sharp. Fix the following notation throughout this paper.
Selective deoxygenation of α,α′-dioxygenated 3-(2H)-furanones

Abstract Regioselective monodeoxygenation of α,α′-dioxygenated 3-(2H)-furanones has been achieved using samarium diiodide in the presence of excess ethylene glycol.
Characterization of multiple line interconnection structures from time domain measurements

An experimental method for the time domain characterization of a class of nonuniformly coupled interconnection lines is presented. Electrical circuit models for constant velocity structures are extracted from time domain reflection (TDR) measurements. >
Solving the Corner-Turning Problem for Large Interferometers

The so-called corner-turning problem is a major bottleneck for radio telescopes with large numbers of antennas. The problem is essentially that of rapidly transposing a matrix that is too large to store on one single device; in radio interferometry, it occurs because data from each antenna need to be routed to an array of processors each of which will handle a limited portion of the data (say, a frequency range) but requires input from each antenna. We present a low-cost solution allowing the correlator to transpose its data in real time, without contending for bandwidth, via a butterfly network requiring neither additional RAM memory nor expensive general-purpose switching hardware. We discuss possible implementations of this using FPGA, CMOS, analog logic and optical technology, and conclude that the corner-turner cost can be small even for upcoming massive radio arrays.
Discovery of the thallium, lead, bismuth, and polonium isotopes

Abstract Forty-two thallium, forty-two lead, forty-one bismuth, and forty-two polonium isotopes have so far been observed; the discovery of these isotopes is described. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.