cssi/SciSciGPT-SciSciNet huggingface dataset:
Local sensory nerve control of skin blood flow during local warming in type 2 diabetes mellitus

Cutaneous sensory nerve-mediated vasodilation is an important component of normal microvascular responsiveness to thermal and nonthermal stimuli. Since both neural and microvascular function can be impaired in type 2 diabetes mellitus (T2DM), we tested the hypothesis that local sensory nerve-mediated vasodilation during nonpainful local warming of the skin is less in T2DM compared with healthy controls (C) matched for age and body size. The rapid vasodilation during the first approximately 5 min of this local warming ("initial peak") was previously shown to rely primarily on local sensory nerves. We measured skin blood flow in T2DM and C subjects (n = 7 in each group) at baseline and during 35 min of local warming of the skin to 42 degrees C at two sites on the ventral forearm. One site was pretreated with 4% lidocaine (LIDO) to block local sensory innervation. During local warming, cutaneous vascular conductance (CVC) during the initial peak was not different between groups, either at the untreated site [T2DM 75 +/- 2 vs. C 81 +/- 6% of maximum CVC (%maxCVC); P > 0.05] or at the LIDO site (T2DM 63 +/- 7 vs. C 64 +/- 6%maxCVC; P > 0.05). The difference between untreated and LIDO sites (sensory nerve contribution) was also similar between groups (T2DM 13 +/- 5 vs. C 18 +/- 5%maxCVC; P > 0.05) and was smaller with LIDO than was previously shown with other local anesthetics. Our results suggest that relatively healthy individuals with T2DM do not exhibit impairments in local sensory nerve vasodilation during thermal stimulation compared with controls of similar age and body size.
The effects of changing exercise levels on weight and age-related weight gain

To determine prospectively whether physical activity can prevent age-related weight gain and whether changing levels of activity affect body weight. The study consisted of 8080 male and 4871 female runners who completed two questionnaires an average (±standard deviation (s.d.)) of 3.20±2.30 and 2.59±2.17 years apart, respectively, as part of the National Runners’ Health Study. Changes in running distance were inversely related to changes in men's and women's body mass indices (BMIs) (slope±standard error (s.e.): −0.015±0.001 and −0.009±0.001 kg/m2 per Δkm/week, respectively), waist circumferences (−0.030±0.002 and −0.022±0.005 cm per Δkm/week, respectively) and percent changes in body weight (−0.062±0.003 and −0.041±0.003% per Δkm/week, respectively, all P<0.0001). The regression slopes were significantly steeper (more negative) in men than women for ΔBMI and Δ%body weight (P<0.0001). A longer history of running diminished the impact of changing running distance on men's weights. When adjusted for Δkm/week, years of aging in men and years of aging in women were associated with increases of 0.066±0.005 and 0.056±0.006 kg/m2 in BMI, respectively, increases of 0.294±0.019 and 0.279±0.028% in Δ%body weight, respectively, and increases of 0.203±0.016 and 0.271±0.033 cm in waist circumference, respectively (all P<0.0001). These regression slopes suggest that vigorous exercise may need to increase 4.4 km/week annually in men and 6.2 km/week annually in women to compensate for the expected gain in weight associated with aging (2.7 and 3.9 km/week annually when correct for the attenuation due to measurement error). Age-related weight gain occurs even among the most active individuals when exercise is constant. Theoretically, vigorous exercise must increase significantly with age to compensate for the expected gain in weight associated with aging.
Counterintuitive transitions in the multistate Landau?Zener problem with linear level crossings

We generalize the Brundobler?Elser hypothesis in the multistate Landau?Zener problem to the case when instead of a state with the highest slope of the diabatic energy level there is a band of states with an arbitrary number of parallel levels having the same slope. We argue that the probabilities of counterintuitive transitions among such states are exactly zero.
7-epizingiberene, a novel bisabolane sesquiterpene from wild tomato leaves

Abstract A C15 hydrocarbon isolated from the leaves of 2 wild tomato species, Lycopersicon hirsutum f glabratum PI 199381 and Lycopersicon hirsutum PI 365906, has been identified as 7 - epizingiberene (2), a diastereomer of zingiberene (1) that occurs in essential oil of ginger. The structure assignment for 2 is based upon its 1H NMR, 13C NMR, IR, UV, and mass spectral characteristics. All spectral data for zingiberene and epizingiberene are identical except for 9 of 15 13C NMR resonances, which establish the diastereomeric relationship of these sesquiterpenes. The 4S, 7R stereochemistry of epizingiberene was proven by dehydrogenation to (7R)- ar - curcumene (4). The opposite 7R and 7S stereochemistry of the zingiberenes implicates the probable occurrence of opposite sidechain rotations of a common (S)-bisabolyl carbocation intermediate (1OA) to allow stereoelectronically favorable hydride shifts in their respective biosyntheses from (E, E)-farnesyl diphosphate.
Diminishing Returns and the Limit of Athletic Performance

The purpose of this paper is to estimate athletic performance profiles over time, to establish that diminishing returns is a characteristic of performance functions, to measure the rate of the marginal decline, and to measure the upper (lower) bound or limit of performance. The empirical results yield estimates of the limiting value of athletic performance and the frontier maximum (minimum) record. Since lower bounds in the running events have been shown to be sensitive to choice of the nonlinear model, logistic and an exponential model for the men's running and distance events are estimated as a cross-check on my differential equation model. The issue of the gender gap (whether women will ever catch men) in athletic performance is also explored.
Coupling a self-dual tensor to gravity in six dimensions

Abstract A recent result concerning interacting theories of self-dual tensor gauge fields in six dimensions is generalized to include coupling to gravity. The formalism makes five of the six general coordinate invariances manifest, whereas the sixth one requires a non-trivial analysis. The result should be helpful in formulating the world-volume action of the M theory five-brane.
Template-Grown Metal Nanowires

The growth of metal nanowires using membranes as hard templates is reviewed. The method provides access to arrays of single-crystal metal nanowires and to quasi-one-dimensional metal nanostructures with controlled compositional variation along their length. Recent applications of these kinds of nanowires to problems in superconductivity, optical spectroscopy and sensing, and catalytic conversion of chemical to mechanical energy are reviewed.
Predictions of pressure-induced transition temperature increase for a variety of high-temperature superconductors

Abstract A wide variety of superconducting oxides are used to test a general model of high-pressure-induced transition temperature ( T c ) changes. The T c vary from a low of 24 K to a high of 164 K. Although the model is capable of predicting both increases and decreases in T c with pressure, only superconductors that exhibit an increase are considered at this time. Predictions are made of the maximum T th cP for 15 superconductors as a function of their compressibilities. The theoretical results generally agree well with experiment. This model of T c as a function of pressure is derived from a recent successful phenomenological theory of short coherence length superconductivity.
In Vivo Protein-Protein Interaction Assays: Beyond Proteins.

The scope of cell-based assays is being expanded to allow the detection of interactions between proteins and DNA, RNA, or small molecules. The yeast two-hybrid assay, which normally detects protein-protein interactions, can be modified to detect interactions between ligands (the two dark yellow shapes in the diagram) and receptors (DHFR or GR). A small bridging molecule (made up of the ligands joined together) is used to join two fusion proteins (DHFR-DBD and AD-GR), thereby activating the reporter gene.
Indentation of polydimethylsiloxane submerged in organic solvents

This work uses a method based on indentation to characterize a polydimethylsiloxane (PDMS) elastomer submerged in an organic solvent (decane, heptane, pentane, or cyclohexane). An indenter is pressed into a disk of a swollen elastomer to a fixed depth, and the force on the indenter is recorded as a function of time. By examining how the relaxation time scales with the radius of contact, one can differentiate the poroelastic behavior from the viscoelastic behavior. By matching the relaxation curve measured experimentally to that derived from the theory of poroelasticity, one can identify elastic constants and permeability. The measured elastic constants are interpreted within the Flory–Huggins theory. The measured permeability indicates that the solvent migrates in PDMS by diffusion, rather than by convection. This work confirms that indentation is a reliable and convenient method to characterize swollen elastomers.
Copolymerization of isobutylene with 1,4‐13C‐isoprene

Copolymers of isobutylene with 1,4-13C-isoprene have been prepared in methyl chloride solvent at −90 to −50°C using aluminum chloride and organoaluminum halide initiators. The examination of these copolymers containing 0.5 to 3.0 mol % of the diolefin by 13C-NMR has given new information about the mechanism of the copolymerization. It appears that every macromolecule ends in an isoprene derived unit; that chain transfer to monomer by an isoprene-derived propagating carbocation is the dominant chain breaking process. The copolymer triad sequences have been unambiguously assigned and analyzed in both batch and continuous stirred tank reactor copolymers. The relative concentrations of the triads agree with those predicted by published reactivity ratios.
Study of throughput and latency in finite-buffer coded networks

Exact queueing analysis of erasure networks with network coding in a finite buffer regime is an extremely hard problem due to the large number of states in the network. In such networks, packets are lost due to either link erasures or due to blocking due to full buffers. In this paper, a block-by-block random linear network coding scheme with feedback on the links is selected for reliability and more importantly guaranteed decoding of each block. We propose a novel method that iteratively estimates the performance parameters of the network and more importantly reduces the computational complexity compared to the exact analysis. The proposed framework yields an accurate estimate of the distribution of buffer occupancies at the intermediate nodes using which we obtain analytical expressions for network throughput and delay distribution of a block of packets.
Bruhat Order for Two Flags and a Line

The classical Ehresmann-Bruhat order describes the possible degenerations of a pair of flags in a linear space V under linear transformations of V; or equivalently, it describes the closure of an orbit of GL(V acting diagonally on the product of two flag varieties. We consider the degenerations of a triple consisting of two flags and a line, or equivalently the closure of an orbit of GL(V) acting diagonally on the product of two flag varieties and a projective space. We give a simple rank criterion to decide whether one triple can degenerate to another. We also classify the minimal degenerations, which involve not only reflections (i.e., transpositions) in the Weyl group SVSn = dim(V, but also cycles of arbitrary length. Our proofs use only elementary linear algebra and combinatorics.
Offering supplementary network technologies: adoption behavior and offloading benefits

To alleviate the congestion caused by rapid growth in demand for mobile data, wireless service providers (WSPs) have begun encouraging users to offload some of their traffic onto supplementary network technologies, e.g., offloading from 3G or 4G to WiFi or femtocells. With the growing popularity of such offerings, a deeper understanding of the underlying economic principles and their impact on technology adoption is necessary. To this end, we develop a model for user adoption of a base technology (e.g., 3G) and a bundle of the base plus a supplementary technology (e.g., 3G + WiFi). Users individually make their adoption decisions based on several factors, including the technologies' intrinsic qualities, negative congestion externalities from other subscribers, and the flat access rates that a WSP charges. We then show how these user-level decisions translate into aggregate adoption dynamics and prove that these converge to a unique equilibrium for a given set of exogenously determined system parameters. We fully characterize these equilibria and study adoption behaviors of interest to a WSP. We then derive analytical expressions for the revenue-maximizing prices and optimal coverage factor for the supplementary technology and examine some resulting nonintuitive user adoption behaviors. Finally, we develop a mobile app to collect empirical 3G/WiFi usage data and numerically investigate the profit-maximizing adoption levels when a WSP accounts for its cost of deploying the supplemental technology and savings from offloading traffic onto this technology.
Quarks: Currents and constituents

An attempt is made to clarify the relation between current quarks and constituent quarks. Assuming that the two are related by a unitary transformation, we outline the properties of this transformation and, in the process, discover a new U(6) \ifmmode\times\else\texttimes\fi{} U(6) \ifmmode\times\else\texttimes\fi{} O(3) classification algebra for the hadrons. An example of this transformation is constructed in the lightlikeplane formulation of the free-quark model, where the transformation is found to be essentially unique and is just the operator solution to the problem of saturating chiral SU(3) \ifmmode\times\else\texttimes\fi{} SU(3). Using the algebraic structure of the free-quark model phenomenologically, matrix elements of currents between different hadrons are related. This abstraction of free-quark algebraic properties works fairly well for the axial-charge and magnetic-moment operators, although it fails for bilocal operators. Nevertheless, we obtain many successful approximate relations between matrix elements of currents, not the least of which is the recovery of the ratio $\frac{{\ensuremath{\mu}}_{T}(\mathrm{proton})}{{\ensuremath{\mu}}_{T}(\mathrm{neutron})}=\ensuremath{-}\frac{3}{2}$.
Quantized Estimation of Gaussian Sequence Models in Euclidean Balls

A central result in statistical theory is Pinsker's theorem, which characterizes the minimax rate in the normal means model of nonparametric estimation. In this paper, we present an extension to Pinsker's theorem where estimation is carried out under storage or communication constraints. In particular, we place limits on the number of bits used to encode an estimator, and analyze the excess risk in terms of this constraint, the signal size, and the noise level. We give sharp upper and lower bounds for the case of a Euclidean ball, which establishes the Pareto-optimal minimax tradeoff between storage and risk in this setting.
Forward-link-power control in CDMA cellular systems

The forward-link (base to mobile) power control problem in code-division multiple access (CDMA) cellular systems is studied. For a better understanding of the problem, a simple analytical model is developed for the neighboring-cell interference experienced by users as a function of distance from their home base station. Using this model, the authors investigate the proposed n/sup th/-power-of-distance power control laws, especially with regard to the possibility of a service hole being created. The investigation leads to the shape of the optimum radial distance dependent power control law that will provide uniform service to all the users. >
Automated information-handling in pharmacology research

Pharmacology involves the multitude of interrelationships between chemical substances and the function of living systems. Since these interrelationships manifest themselves at all levels of physiological organization from the individual enzyme to the intact mammal, research in this area involves concepts and techniques from almost every biomedical discipline. Thus, pharmacology entails a class of information-handling problems as formidable and enticing as any that can be found in the medical area. In recognition of this, the National Institutes of Health (NIH), through its Chemical/Biological Information-Handling (CBIH) Program, is attempting to accelerate the acquisition of new pharmacological knowledge by designing and developing special computer-based research tools. Working through a tightly interconnected set of contracts with universities, research institutes, profit-making organizations, and government agencies, the CBIH Program seeks to blend the most advanced information science methods into a computer system which can be an almost indispensable logistical and cognitive aid to these investigators.
Instrumentation for the cornell ERL injector test cryostats

Cornell is building a 1.3 GHz Injector Cryomodule for an ERL prototype. The cryomodule consists of five two-cell niobium cavities, each cavity having two coaxial input couplers. Cavity and coupler pairs require acceptance testing at high power prior to assembly in the injector cryomodule. A liquid nitrogen cryostat for testing the couplers at high power has been built and the first input coupler test is complete. In addition, a Horizontal Test Cryostat (HTC) is being built to test input coupler pairs and cavities as a set. The first HTC test is scheduled for summer 2007. Details for instrumentation of the Coupler Test Cryostat (CTC) and HTC are presented.
Fast Vision-guided Mobile Robot Navigation Using Model-based Reasoning And Prediction Of Uncertainties

The model-based vision system described in this thesis allows a mobile robot to navigate indoors at an average speed of 8 meters/minute using ordinary laboratory computing hardware of approximately 16 MIPS power. The navigation capabilities of the robot are not impaired by the presence of the stationary or moving obstacles. The vision system maintains a model of uncertainty and keeps track of the growth of uncertainty as the robot travels towards the goal position. The estimates of uncertainty are then used to predict bounds on the locations and orientations of landmarks expected to be seen in a monocular image. This greatly reduces the search for establishing correspondence between the features visible in the image and the landmarks. Given a sequence of image features and a sequence of landmarks derived from a geometric model of the environment, a special aspect of our vision system is the sequential reduction in the uncertainty as each image feature is matched successfully with a landmark, allowing subsequent features to be matched more easily, this being a natural byproduct of the manner in which we use Kalman-filter based updating. Strategies for path planning, path replanning and perception planning are introduced for the robot to navigate in the presence of obstacles. Finally, experimental results are presented.
The formulary model for flexible privacy and access controls

This paper presents a model for engineering the user interface for large data base systems in order to maintain flexible access controls over sensitive data. The model is independent of both machine and data base structure, and is sufficiently modular to allow cost-effectiveness studies on access mechanisms. Access control is based on sets of procedures called formularies. The decision on whether a user can read, write, update, etc., data is controlled by programs (not merely bits or tables of data) which can be completely independent of the contents or location of raw data in the data base.
Monte Carlo based formula for radiation shielding assessment in the forward direction

Monte Carlo simulations of 800-MeV proton beam spills in common shielding materials show that neutron dose equivalent rates in the forward direction can be characterized by a Moyer Model-like formula. Particle transport codes were used to determine the neutron flux at depths up to 6 meters and for production angles from 0/spl deg/ to 30/spl deg/ for primary proton-beam spills on cylindrical beam stops. The flux was then converted to dose equivalent rate as a function of depth and angle. The results for three common shielding materials were combined and the resulting fitted formula provides a quick method for estimating the dose equivalent rates and shielding effectiveness outside thick shielding at forward angles. >
Nowhere minimal CR submanifolds and Levi-flat hypersurfaces

A local uniqueness property of holomorphic functions on real-analytic nowhere minimal CR submanifolds of higher codimension is investigated. A sufficient condition called almost minimality is given and studied. A weaker necessary condition, being contained a possibly singular real-analytic Levi-flat hypersurface is studied and characterized. This question is completely resolved for algebraic submanifolds of codimension 2 and a sufficient condition for noncontainment is given for non algebraic submanifolds. As a consequence, an example of a submanifold of codimension 2, not biholomorphically equivalent to an algebraic one, is given. We also investigate the structure of singularities of Levi-flat hypersurfaces.
Non-perturbative dynamics in supersymmetric gauge theories

Abstract I give an introductory review of recent, fascinating developments in supersymmetric gauge theories. I explain pedagogically the miraculous properties of supersymmetric gauge dynamics allowing one to obtain exact solutions in many instances. Various dynamical regimes emerging in supersymmetric Quantum Chromodynamics and its generalizations are discussed. I emphasize those features that have a chance of survival in QCD and those which are drastically different in supersymmetric and non-supersymmetric gauge theories. Unlike most of the recent reviews focusing almost entirely on the progress in extended supersymmetries (the Seiberg-Witten solution of N = 2 models), these lectures are mainly devoted to N = 1 theories. The primary task is extracting lessons for non-supersymmetric theories.
Aerodynamic data modeling using support vector machines

Aerodynamic data modeling plays an important role in aerospace and industrial fluid engineering. Support vector machines (SVMs), as a novel type of learning algorithms based on the statistical learning theory, can be used for regression problems and have been reported to perform well with promising results. The work presented here examines the feasibility of applying SVMs to the aerodynamic modeling field. Mainly, the empirical comparisons between the SVMs and the commonly used neural network technique are carried out through two practical data modeling cases – performance-prediction of a new prototype mixer for engine combustors, and calibration of a five-hole pressure probe. A CFD-based diffuser optimization design is also involved in the article, in which an SVM is used to construct a response surface and hereby to make the optimization perform on an easily computable surrogate space. The obtained simulation results in all the application cases demonstrate that SVMs are the potential options for the ch...
The role of knowledge and certainty in understanding for dialogue

As people engage in increasingly complex conversations with computers, the need for generality and flexibility in spoken dialogue systems becomes more apparent. This paper describes how three different spoken dialogue systems for the same task reason with knowledge and certainty as they seek to understand what people want. It advocates systems that exploit partial understanding, consider credibility, and are aware both of what they know and of their certainty that it matches their users’ intent.
Scaling Graph-based Semi Supervised Learning to Large Number of Labels Using Count-Min Sketch

Graph-based Semi-supervised learning (SSL) algorithms have been successfully used in a large number of applications. These methods classify initially unlabeled nodes by propagating label information over the structure of graph starting from seed nodes. Graph-based SSL algorithms usually scale linearly with the number of distinct labels (m), and require O(m) space on each node. Unfortunately, there exist many applications of practical signicance with very large m over large graphs, demanding better space and time complexity. In this paper, we propose MAD-Sketch, a novel graph-based SSL algorithm which compactly stores label distribution on each node using Count-min Sketch, a randomized data structure. We present theoretical analysis showing that under mild conditions, MAD-Sketch can reduce space complexity at each node from O(m) to O(logm), and achieve similar savings in time complexity as well. We support our analysis through experiments on multiple real world datasets. We observe that MAD-Sketch achieves similar performance as existing state-of-the-art graph-based SSL algorithms, while requiring smaller memory footprint and at the same time achieving up to 10x speedup. We nd that MAD-Sketch is able to scale to datasets with one million labels, which is beyond the scope of existing graph-based SSL algorithms.
Power allocation strategies and lattice based coding schemes for bi-directional relaying

We consider a communication system where two transmitters wish to exchange information through a half-duplex relay in the middle. The channels between the transmitters and the relay have asymmetric channel gains. More specifically, the channels are assumed to be synchronized with complex inputs and complex fading coefficients with an average power constraint on the inputs to the channels. The noise at the receivers have the same power spectral density and are assumed to be white and Gaussian. We restrict our attention to transmission schemes where information from the two nodes are simultaneously sent to the relay during a medium access phase followed by a broadcast phase where the relay broadcasts information to both the nodes. An upper bound on the capacity for the two phase protocol under a sum power constraint on the transmit power from all the nodes is obtained as a solution to a convex optimization problem. We show that a scheme using channel inversion with lattice decoding can obtain a rate a small constant 0:09 bits from the upper bound at high signal-to-noise ratios. Numerical results show that the proposed scheme can perform very close to the upper bound.
Do Tax Havens Flourish

Tax haven countries offer foreign investors low tax rates and other tax features designed to attract investment and thereby stimulate economic activity. Major tax havens have less than 1 percent of the world's population (outside the United States) and 2.3 percent of world gross domestic product (GDP), but they host 5.7 percent of the foreign employment and 8.4 percent of foreign property, plant, and equipment of American firms. Per capita real GDP in tax haven countries grew at an average annual rate of 3.3 percent between 1982 and 1999, which compares favorably to the world average of 1.4 percent. Tax haven governments appear to be adequately funded: their average 25 percent ratio of government to GDP exceeds the 20 percent ratio for the world as a whole, though the small populations and relative affluence of these countries would normally be associated with even larger governments. Whether the economic prosperity of tax haven countries comes at the expense of higher tax countries is unclear. Recent res...
The effects of low temporal frequency modes on minimum variance maps from planck.

We estimate the effects of low temporal frequency modes in the time stream on sky maps such as expected from the  experiment - a satellite mission designed to image the sky in the microwave band. We perform the computations in a semi-analytic way based on a simple model of  observations, which permits an insight into the structure of noise correlations of -like maps, without doing exact, computationally intensive numerical calculations. We show that, for a set of plausible scanning strategies, marginalization over temporal frequency modes with frequencies lower than the spin frequency of the satellite (� 1/60 Hz) causes a nearly negligible deterioration of a quality of the resulting sky maps. We point out that this observation implies that it should be possible to successfully remove effects of long-term time domain parasitic signals from the  maps during the data analysis stage.
Syntheses of 1,4-benzothiazepines and 1,4-benzoxazepines via cyclizations of 1-[2-arylthio(oxy)ethyl]-5-benzotriazolyl-2-pyrrolidinones and 3-benzotriazolyl-2-[2-arylthio(oxy)ethyl]-1-isoindolinones.

1-[2-Arylthio(oxy)ethyl]-5-benzotriazolyl-2-pyrrolidinones 6a−e, 12 and 3-benzotriazolyl-2-[2-arylthio(oxy)ethyl]-1-isoindolinones 9a−f, 14 are readily available from reactions of benzotriazole (4), 2-(arylsulfanyl)ethylamines 3, or 2-phenoxyethylamine (11) with 2,5-dimethoxy-2,5-dihydrofuran (5) or 2-formylbenzoic acid (8). Lewis acid mediated cyclizations of 6 and 9 produced novel 1,4-benzothiazepines 7a−e and 10a−f, respectively. Cyclizations of 12 and 14 gave 1,4-benzoxazepines 13 and 15, respectively.
Making Sparse Gaussian Elimination Scalable by Static Pivoting

We propose several techniques as alternatives to partial pivoting to stabilize sparse Gaussian elimination. From numerical experiments we demonstrate that for a wide range of problems the new method is as stable as partial pivoting. The main advantage of the new method over partial pivoting is that it permits a priori determination of data structures and communication pattern for Gaussian elimination, which makes it more scalable on distributed memory machines. Based on this a priori knowledge, we design highly parallel algorithms for both sparse Gaussian elimination and triangular solve and we show that they are suitable for large-scale distributed memory machines.
A Global Model of Technological Utilization Based on Governmental, Business-Investment, Social, and Economic Factors

This exploratory paper presents a conceptual model of the factors of governmental support and openness, business and technology investment, and socioeconomic level that are posited to influence technological utilization. The conceptual model and conjectures are developed inductively based on logic and prior research about the relationship among variables related to the factors. Structural equation modeling (SEM) is applied to operationalize and test the model. The SEM analysis tests five points of investigation on a large sample of country data from the World Bank and the World Economic Forum. Findings indicate a critical pathway of associations between the factors of government support and openness, investment in business and technology, socioeconomic level, and technology utilization. The paper presents two country case examples of the model and suggests policy steps for national governments of developed and developing countries to prioritize information and communications technology, create openness, strengthen research and development and technology investment, and enhance education and information technology training.
The Passage Time Distribution for a Birth-and-Death Chain: Strong Stationary Duality Gives a First Stochastic Proof

A well-known theorem usually attributed to Keilson states that, for an irreducible continuous-time birth-and-death chain on the nonnegative integers and any d, the passage time from state 0 to state d is distributed as a sum of d independent exponential random variables. Until now, no probabilistic proof of the theorem has been known. In this paper we use the theory of strong stationary duality to give a stochastic proof of a similar result for discrete-time birth-and-death chains and geometric random variables, and the continuous-time result (which can also be given a direct stochastic proof) then follows immediately. In both cases we link the parameters of the distributions to eigenvalue information about the chain. We also discuss how the continuous-time result leads to a proof of the Ray–Knight theorem.
Modeling of the interaction of a side jet with a rarefied atmosphere

The interaction of a jet from a 3000-N-class thruster positioned on the side of a small rocket, with the rarefied atmosphere at 100 and 80 km, is studied numerically. The direct simulation Monte Carlo method was applied to model the three-dimensional jet-atmosphere interaction. Chemical reactions between freestream and plume species were included in the simulations. A two-stage numerical strategy was used, with sequential computations of an axisymmetric plume core flow and three-dimensional plume-freestream interaction. The impact of altitude, angle of attack, rocket velocity, and thrust on flowfields and surface mass fluxes is examined.
Acoustic Signatures in the Cosmic Microwave Background

We study the uniqueness and robustness of acoustic signatures in the cosmic microwave background by allowing for the possibility that they are generated by some as yet unknown source of gravitational perturbations. The acoustic pattern of peak locations and relative heights predicted by the standard inflationary cold dark matter model is essentially unique, and its confirrmation would have deep implications for the causal structure of the early universe. A generic pattern for isocurvature initial conditions arises due to backreaction effects but is not robust to exotic source behavior inside the horizon. If present, the acoustic pattern contains unambiguous information on the curvature of the universe even in the general case. By classifying the behavior of the unknown source, we determine the minimal observations necessary for robust constraints on the curvature. The diffusion damping scale provides an entirely model-independent cornerstone upon which to build such a measurement. The peak spacing, if regular, supplies a precision test.
Controlled symmetries and passive walking

In this note, we investigate the relationship between nonlinear control and passive walking in bipedal locomotion for the general case of an n degree-of-freedom biped in three dimensional space. We introduce the notion of controlled symmetry to capture the effect of the control input on the invariance of the system Lagrangian under group action. We then show the existence of a controlled symmetry for general bipeds under the action of SO(3) taking into account not only the kinetic energy but also the potential energy and impact dynamics. We use this result to show the existence of a nonlinear control law that reproduces so-called passive gaits independent of the particular ground slope. Our contribution in this note is two-fold. First, our result contains the first rigorous proof of the existence of so-called passivity mimicking control laws that explicitly accounts for the impact dynamics. Second, whereas previous papers have studied only planar bipeds with and without knees, our result is completely general. Our results can be viewed as direct extensions of several previous results, such as passivity-based control, virtual gravity, and virtual passive dynamic walking from the planar case to general n-degrees-of-freedom (DOF) robots in three-dimensional space.
A Natural Prime-Generating Recurrence

For the sequence defined by a(n) = a(n − 1) + gcd(n, a(n − 1)) with a(1) = 7 we prove that a(n) − a(n − 1) takes on only 1’s and primes, making this recurrence a rare “naturally occurring” generator of primes. Toward a generalization of this result to an arbitrary initial condition, we also study the limiting behavior of a(n)/n and a transience property of the evolution.
Algorithms for Secretary Problems on Graphs and Hypergraphs

We examine online matching problems with applications to Internet advertising reservation systems. Consider an edge-weighted bipartite graph G (L *** R , E ). We develop an 8-competitive algorithm for the following secretary problem: Initially given R , and the size of L , the algorithm receives the vertices of L sequentially, in a random order. When a vertex l *** L is seen, all edges incident to l are revealed, together with their weights. The algorithm must immediately either match l to an available vertex of R , or decide that l will remain unmatched. In [5], the authors show a 16-competitive algorithm for the transversal matroid secretary problem, which is the special case with weights on vertices, not edges. (Equivalently, one may assume that for each l *** L , the weights on all edges incident to l are identical.) We use a very similar algorithm, but simplify and improve the analysis to obtain a better competitive ratio for the more general problem. Our analysis is easily extended to obtain competitive algorithms for a class of similar problems, such as to find disjoint sets of edges in hypergraphs where edges arrive online. We also introduce secretary problems with adversarially chosen groups . Finally, we give a 2e -competitive algorithm for the secretary problem on graphic matroids, where, with edges appearing online, the goal is to find a maximum-weight acyclic subgraph of a given graph.
Understanding image intensities

Traditionally, image intensities have been processed to segment an image into regions or to find edge-fragments. Image intensities carry a great deal more information about three-dimensional shape, however. To exploit this information, it is necessary to understand how images are formed and what determines the observed intensity in the image. The gradient space, popularized by Huffman and Mackworth in a slightly different context, is a helpful tool in the development of new methods.
Network Responsiveness: The Social Structural Microfoundations of Dynamic Capabilities

Intraorganizational social networks are known to be important antecedents to individual career attainment, but research examining their influence on firm-level performance has been limited. We argue that the intrafirm network is likely to affect two firm-level outcomes: coordination and adaptability. Prior research has shown formal structure to be a useful tool for reshaping organizational networks, but we argue that firms vary in their rates of network responsiveness. When formal organizational structure is changed, as in a reorganization, or when targeted individuals undertake job changes, some firms will experience a rapid reshaping of their networks; in other firms, the network will respond more slowly to the new formal structure. We posit that slow network responsiveness may provide coordination advantages via compensatory fit, whereas fast network responsiveness may facilitate more rapid adaptability. As such, a firm's rate of network responsiveness is a heretofore unexplored source of dynamic capab...
Thermochemistry of some binary alloys of Samarium with the noble metals (Cu, Ag, Au) by high temperature direct synthesis calorimetry

Abstract The standard enthalpies of formation of some Samarium compounds with noble metals (Cu, Ag, Au) have been measured by high temperature direct synthesis calorimetry at 1273 ± 2 K. The following results (in kJ/mol of atoms) are reported: CuSm (−12.4 ± 1.9); Cu 2 Sm (−16.7 ± 2.1); Cu 6 Sm (−13.7 ± 1.5); AgSm (−37.0 ± 2.7); Ag 2 Sm (−24.1 ± 2.4); Ag 51 Sm 14 (−16.8 ± 3.5); AuSm (−76.3 ± 2.0); Au 2 Sm (−77.1 ± 1.3); Au 51 Sm 14 (−59.8 ± 2.3). The results are compared with the predictions of the semi-empirical model of Miedema and co-workers. The results are also compared with the recently reported enthalpies of formation of the Cu–LA, Ag–LA and Au–LA systems by the present authors.
NEW APPROACHES TO UNDERSTANDING RACIAL PREJUDICE AND DISCRIMINATION

This chapter reviews and critiques recent work on prejudice, discrimination, and racism, with an emphasis on evidence of continuing discrimination in the United States and efforts to understand its basis in prejudice. Three lines of research are the primary subject of the review: recent work on the measurement of discrimination, especially audit methods; theories of new prejudice and new racism following the Civil Rights movement; and research on implicit prejudicial attitudes. The most sophisticated new work on prejudice and discrimination is characterized by a multidimensional understanding of prejudice and/or the use of experimental methods. This review argues that research on implicit prejudice, largely developed by psychologists, provides an important new understanding of the basis of discrimination and should be incorporated in sociological accounts.
Phosphine‐Based Redox Catalysis in the Direct Traceless Staudinger Ligation of Carboxylic Acids and Azides

The synthesis of amide C N bonds through nucleophilic acyl substitutions constitutes one of the most fundamental transformations in chemical synthesis. Recently, the Staudingertype ligation of carboxylic acid derivatives (e.g., acid chlorides, anhydrides, acyl selenides, and thioesters) and azides has become a preeminent strategy for amide C N bond construction (Scheme 1a). However, the generation of
A smooth transition from powerlessness to absolute power

We study the phase transition of the coalitional manipulation problem for generalized scoring rules. Previously it has been shown that, under some conditions on the distribution of votes, if the number of manipulators is o (√n), where n is the number of voters, then the probability that a random profile is manipulable by the coalition goes to zero as the number of voters goes to infinity, whereas if the number of manipulators is ω(√n), then the probability that a random profile is manipulable goes to one. Here we consider the critical window, where a coalition has size c√n, and we show that as c goes from zero to infinity, the limiting probability that a random profile is manipulable goes from zero to one in a smooth fashion, i.e., there is a smooth phase transition between the two regimes. This result analytically validates recent empirical results, and suggests that deciding the coalitional manipulation problem may be of limited computational hardness in practice.
Assessment of Damage in Ceramics and Ceramic Matrix Composites Using Ultrasonic Techniques

We address the application of ultrasonic methods to damage assessment in ceramics and ceramic matrix composites. We focuse on damage caused by thermal shock and oxidation at elevated temperatures. The damage-induced changes in elastic constants and elastic anisotropy are determined by measuring the velocities of ultrasonic waves in different propagation directions within the sample. Thermal shock damage measurement is performed in ceramic samples of reaction bonded silicon nitride (RBSN) and aluminum oxide. Thermal shock treatment from different temperatures up to 1000°C is applied to produce the microcracks. Both surface and bulk ultrasonic wave methods are used to correlate the change of elastic constants to microstructural degradation and to determine the change in elastic anisotropy induced by microcrack damage. Oxidation damage is studied in silicon carbide fiber/reaction bonded silicon nitride matrix (SCS-6/RBSN) composites. The oxidation is done by exposing the samples in a flowing oxygen environment at elevated temperatures, up to 1400°C, for 100 hours. Significant changes of ultrasonic velocities were observed for composites before and after oxidation. The elastic constants of the composites were determined from the measured velocity data. The Young's modulus in the fiber direction as obtained from ultrasonic measurements decreases significantly at 600°C but retains its original value at temperatures above 1200°C. This agrees well with the results of destructive tests by other authors. The transverse longitudinal and shear moduli obtained from ultrasonic measurements decrease continually until 1200°C. The results show that the damage-induced anisotropy in both ceramics and ceramic matrix composites can be determined successfully by ultrasonic methods. This suggests the possibility of assessing damage severity using ultrasonic techniques
Microwave Thermolysis with Clayfen: Solvent-Free Oxidation of Sulfides to Sulfoxides

Abstract Alkyl, aryl and cyclic sulfides are rapidly oxidized to the corresponding sulfoxides in high yields upon microwave thermolysis with iron(III) nitrate impregnated on clay (clayfen) under solvent-free conditions; the conversion also occurs in refluxing methylene chloride but requires much longer reaction time.
Cancer Cell Metabolism: One Hallmark, Many Faces

Cancer cells must rewire cellular metabolism to satisfy the demands of growth and proliferation. Although many of the metabolic alterations are largely similar to those in normal proliferating cells, they are aberrantly driven in cancer by a combination of genetic lesions and nongenetic factors such as the tumor microenvironment. However, a single model of altered tumor metabolism does not describe the sum of metabolic changes that can support cell growth. Instead, the diversity of such changes within the metabolic program of a cancer cell can dictate by what means proliferative rewiring is driven, and can also impart heterogeneity in the metabolic dependencies of the cell. A better understanding of this heterogeneity may enable the development and optimization of therapeutic strategies that target tumor metabolism. Significance: Altered tumor metabolism is now a generally regarded hallmark of cancer. Nevertheless, the recognition of metabolic heterogeneity in cancer is becoming clearer as a result of advancements in several tools used to interrogate metabolic rewiring and dependencies. Deciphering this context-dependent heterogeneity will supplement our current understanding of tumor metabolism and may yield promising therapeutic and diagnostic utilities. Cancer Discov; 2(10); 881–98. ©2012 AACR .
Amino Azaxylylenes Photogenerated from o‐Amido Imines: Photoassisted Access to Complex Spiro‐Poly‐Heterocycles

Upon irradiation, cyclic imines containing o-amido groups are shown to produce reactive intermediates, amino azaxylylenes, which undergo intramolecular cycloadditions to tethered unsaturated pendants to yield complex N,O-heterocycles having an additional spiro-connected nitrogen heterocyclic moiety. Modular assembly of the photoprecursors allows expeditious increase of the complexity of the target poly-heterocyclic scaffolds with a minimal number of experimentally simple reaction steps. The photocyclization and subsequent postphotochemical transformations are accompanied by an increase of Lovering's fsp3 factor, thus producing unprecedented three-dimensional molecular architectures, and offering extended sampling of chemical space.
War as a Commitment Problem

Although formal work on war generally sees war as a kind of bargaining breakdown resulting from asymmetric information, bargaining indivisibilities, or commitment problems, most analyses have focused on informational issues. But informational explanations and the models underlying them have at least two major limitations: they often provide a poor account of prolonged conflict, and they give an odd reading of the history of some cases. This article describes these limitations and argues that bargaining indivisibilities should really be seen as commitment problems. The present analysis then shows that a common mechanism links three important kinds of commitment problem: (1) preventive war, (2) preemptive attacks arising from first-strike or offensive advantages, and (3) conflicts resulting from bargaining over issues that affect future bargaining power. In each case, large, rapid shifts in the distribution of power can lead to war. Finally, the analysis elaborates a distinctly different mechanism based on a comparison of the cost of deterring an attack on the status quo with the expected cost of trying to eliminate the threat to the status quo.For helpful comments and criticisms, I thank James Fearon, Hein Goemans, Lisa Martin, Sebastian Mazzuca, Branislav Slantchev, and seminar participants at the University of Montreal–McGill Research Group in International Security, the Institute in Mathematical Behavioral Sciences, University of California, Irvine, and University of California, Santa Barbara. I also gratefully acknowledge the support of the National Science Foundation (SES-0315037).