cssi/SciSciGPT-SciSciNet huggingface dataset:
Meissner effect, Spin Meissner effect and charge expulsion in superconductors

The Meissner effect and the Spin Meissner effect are the spontaneous generation of charge and spin current respectively near the surface of a metal, making a transi- tion to the superconducting state. The Meissner effect is well known but, I argue, not explained by the conventional the- ory; the Spin Meissner effect has yet to be detected. I pro- pose that both effects take place in all superconductors, the first one in the presence of an applied magnetostatic field, the second one even in the absence of applied external fields. Both effects can be understood under the assumption that electrons expand their orbits and thereby lower their quan- tum kinetic energy in the transition to superconductivity. As- sociated with this process, the metal expels negative charge from the interior to the surface and an electric field is gener- ated in the interior. The resulting charge current can be un- derstood as arising from the magnetic Lorenz force on radi- ally outgoing electrons, and the resulting spin current can be understood as arising from a spin Hall effect originating in the Rashba-like coupling of the electron magnetic moment to the internal electric field. The associated electrodynamics is qualitatively different from London electrodynamics, yet can be described by a small modification of the conventional London equations. The stability of the superconducting state and its macroscopic phase coherence hinge on the fact that the orbital angular momentum of the carriers of the spin cur- rent is found to be exactly /2, indicating a topological ori- gin. The simplicity and universality of our theory argue for its validity, and the occurrence of superconductivity in many classes of materials can be understood within our theory.
Hochster's theta invariant and the Hodge–Riemann bilinear relations

Abstract Let R be an isolated hypersurface singularity, and let M and N be finitely generated R -modules. As R is a hypersurface, the torsion modules of M against N are eventually periodic of period two (i.e., Tor i R ( M , N ) ≅ Tor i + 2 R ( M , N ) for i ≫ 0 ). Since R has only an isolated singularity, these torsion modules are of finite length for i ≫ 0 . The theta invariant of the pair ( M , N ) is defined by Hochster to be length ( Tor 2 i R ( M , N ) ) − length ( Tor 2 i + 1 R ( M , N ) ) for i ≫ 0 . H. Dao has conjectured that the theta invariant is zero for all pairs ( M , N ) when R has even dimension and contains a field. This paper proves this conjecture under the additional assumption that R is graded with its irrelevant maximal ideal giving the isolated singularity. We also give a careful analysis of the theta pairing when the dimension of R is odd, and relate it to a classical pairing on the smooth variety Proj ( R ) .
A Khintchine type theorem for hyperplanes

The convergence case of a Khintchine-type theorem for a large class of hyperplanes is obtained. The approach to the problem is from a dynamical viewpoint, and a method due to Kleinbock and Margulis is modified to prove the result.
Factors Associated With Severe Late Toxicity After Concurrent Chemoradiation for Locally Advanced Head and Neck Cancer: An RTOG Analysis

Purpose Concurrent chemoradiotherapy (CCRT) for squamous cell carcinoma of the head and neck (SCCHN) increases both local tumor control and toxicity. This study evaluates clinical factors that are associated with and might predict severe late toxicity after CCRT. Methods Patients were analyzed from a subset of three previously reported Radiation Therapy Oncology Group (RTOG) trials of CCRT for locally advanced SCCHN (RTOG 91-11, 97-03, and 99-14). Severe late toxicity was defined in this secondary analysis as chronic grade 3 to 4 pharyngeal/laryngeal toxicity (RTOG/European Organisation for the Research and Treatment of Cancer late toxicity scoring system) and/or requirement for a feeding tube ≥ 2 years after registration and/or potential treatment-related death (eg, pneumonia) within 3 years. Case-control analysis was performed, with a multivariable logistic regression model that included pretreatment and treatment potential factors. Results A total of 230 patients were assessable for this analysis: 99 p...
a-Si/c-Si Solar Cells: Effect of Preparation and Processing Techniques on the Photovoltaic Properties

The photovoltaic (PV) properties of undoped amorphous silicon (a-Si)/ p-type crystalline silicon (c-Si) solar cells were found to improve by a hydrofluoric acid treatment of c-Si just prior to glow discharge deposition of a-Si. The short circuit current density (Jsc) improved from 2.7 to 23.5 mA/cm2 for an 0.1 µm thick a-Si layer. This also resulted in an improved spectral response of the solar cell in the violet region of the spectrum. The enhanced properties have been attributed to the improved carrier transport across the interface, as seen in the current-voltage-temperature relationships, and also PC-ID simulation of the devices. Solar cells of a similar type were also fabricated by dc magnetron sputtering of the a-Si layer. HF passivated cells (area ~ 0.24 cm2) yielded about 9.5 % efficiency with Jsc of 30 mA/cm2 and a FF of 0.6, without use of an A/R coating. The variation of the PV properties of these cells was investigated as a function of a-Si thickness and c-Si doping.
Furanosides and furanones bearing acrylate sidechains via palladium-mediated cyclizations of γ-Oxoallenes

Abstract Treatment of 4,5-hexadienal with catalytic palladium(II) chloride and excess copper(II) chloride, methanol and carbon monoxide in the presence of an acid and a water scavenger resulted in a net acetalization-cyclization- methoxycarbonylation to form a novel methyl furanoside bearing a methyl acrylate sidechain. Treatment of 4,5- hexadienoic acid under the same conditions yields the corresponding furanone, and 3-( tert -butyldimethylsilyloxy)-4,5- hexadienal yields a methyl β-3'-( tert -butyldimethylsilyloxy)-2′-deoxyribofuranoside bearing the acrylate sidechain, with high stereoselectivity. This methodology provides access to sidechain-branched ribofuranoside compounds.
Microwave time delay beamforming using optics

A practicable method of driving 2-D arrays using time delay waveforms for both transmit and receive is presented. An optical subsystem generates a set of delayed signals which are transferred to the elements by fiber optics. The time delays are generated by creating frequency-dependent microwave phase shifts in the optical system. An optical fiber array spatially samples optical wavefronts and transfers the optical signals to the array where they are heterodyne detected to recreate the microwave signals at the input to transmit-receive (TR) modules. This process essentially extends the backplane of the antenna back to the control system where element level operations may be performed. All beamforming and nullforming functions may be implemented, e.g. monopulse. The requisite TR modules have no phase shifters and a minimum of logic. >
A new Lanczos method for electronic structure calculations

In the heart of most electronic structure simulation programs, there is a routine to find the solution of eigenvalue problems. Solving these eigenvalue problems usually dominates the computer time used for the whole simulation[6]. Because of their physical properties, these eigenvalue problems are always symmetric real or Hermitian. The dimensions of the matrices involved are usually very large and a large number of eigenvalues and their corresponding eigenvectors are needed to compute the desired physical quantities. To solve this type of problems, we introduce a variant of the Lanczos method called the thick-restart Lanczos method. In material science, this method is most appropriate for non-selfconsistent cases where the eigenvalue problems are linear and the number of required eigenvalues is relatively small compared to the size of the matrix.The Lanczos method is very simple and yet effective in finding eigenvalues. It is also well suited for parallel computing. There are two common ways of implementing the Lanczos method depending on whether the Lanczos vectors are stored. When the Lanczos vectors are not stored, they may lose orthogonality and the Lanczos method may generate spurious eigenvalues [2, 10]. Though spurious eigenvalues can be effectively identified, we still prefer not to deal with the spurious eigenvalues. When the Lanczos vectors are stored, the loss of orthogonality problem can be corrected by re-orthogonalization [4, 5, 7]. No spurious eigenvalue is generated in this case. However, because each Lanczos step generates one vector, a large amount of computer memory may be required to store all the Lanczos vectors. To limit the maximum amount of memory used, we typically restart the Lanczos algorithm after a certain number of steps. The restarted versions usually use considerably more matrix-vector multiplications than the non-restarted version. In recent years, newly developed restarting strategies have significantly reduced the number of matrix-vector multiplications used. The two most successful ones are the implicit restarting technique [1, 3, 8] and the dynamic thick-restart technique [9, 12]. For symmetric or Hermitian eigenvalue problems, these two schemes are equivalent. Because the thick-restart scheme is easier to implement and it is slightly more flexible than the implicit restarted scheme [9, 12], the new method described here uses the thick-restart scheme. Other thick-restart eigenvalue methods, e.g., the thick-restart Davidson method, can be applied on symmetric eigenvalue problems as well. Compared to them, the main advantage of the new scheme is that it uses less arithmetic operations by taking full advantage of the symmetry of the matrix [13].
Chandra X-Ray Spectroscopy and Imaging of the Galaxy Cluster PKS 0745–191

We present a detailed spectral and spatial analysis of the galaxy cluster PKS 0745-191, using recent observations from the Chandra X-Ray Observatory. The data provide information on the temperature and metallicity of the intracluster medium, the distribution of emission throughout the cluster, morphology of the cluster core, and an independent mass estimate that can be compared to that from gravitational lensing. X-ray spectra extracted from the central 300 kpc (~2') are well described by a two-temperature plasma, and the mean cluster temperature is consistent with previously determined values. The distribution of both temperature and metallicity within the inner 360 kpc (23) of PKS 0745-191 is probed on scales of 8'' (~20 kpc), yielding a relatively constant abundance throughout the region and a strong temperature gradient (down to ~4-5 keV) within the central 215 kpc. β-model fits to the surface brightness profile of PKS 0745-191 indicate that a second β-model component is required to fit the inner ~10 kpc. Imaging analysis of the cluster core reveals an irregular morphology within the inner 50 kpc and confirms that the X-ray emission peak lies within 05 (the spatial resolution of Chandra) of both the optical and radio central cD positions. The cluster mass, based on both two-temperature and multiphase fits to the X-ray spectrum, is in close agreement with lensing mass estimates of PKS 0745-191.
FAIR VALUE OF WHOLE-FARM AND CROP-SPECIFIC REVENUE INSURANCE

The U.S. market in subsidized commodity revenue insurance contracts has expanded rapidly since 1996. By far the most prevalent contract forms are crop-specific, rather than the whole-farm design which has a better claim to being optimal. For an arbitrary acre allocation vector, this paper inquires into absolute and relative determinants of the actuarial costs of these forms. The actuarial value of whole-farm insurance increases under a particular characterization of >more systematic= risk, whereas the actuarial value of insurance through crop-specific contracts need not change. Upon fixing stochastic revenue interactions, we identify conditions such that the expected cost of revenue insurance via crop-specific contracts is increasing under a more dispersed vector of location-and-scale adjusted revenue guarantee parameters. Then we identify two precise requirements such that the actuarial values of the two contract forms converge. To give insights on the difference, fair premiums for whole-farm and crop-specific contracts are compared for typical farms in two states.
Non-cyclopentadienyl organometallic compounds of calcium, strontium and barium

Abstract The use of sterically demanding ligands has allowed the organometallic compounds of the heavy alkaline-earth metals calcium, strontium and barium to emerge from the shadow cast by the far better studied organomagnesium Grignard reagents. Metallocenes and other cyclopentadienyl-based complexes have been the most intensively investigated, but in the past decade a wealth of new non-cyclopentadienyl compounds have been characterized. A broad range of structure types are known, encompassing σ- and π-bound anionic ligands, and Lewis base adducts with neutral donors. In this review, crystallographically characterized complexes are discussed, and current interpretations of the bonding in heavier Group 2 element compounds are examined. Recent applications of non-cyclopentadienyl compounds in organic synthesis are surveyed.
Highest energy cosmic-rays and results from the HiRes experiment

The status of the field of ultrahigh energy cosmic-ray physics is summarized, from the point of view of the latest results of the High-Resolution Fly's Eye (HiRes) Experiment. HiRes results are presented, and compared with those of the Akeno Giant Air Shower Array (AGASA), plus the Telescope Array and Pierre Auger experiments. The HiRes measurement of the cosmic-ray spectrum and the observation of the GZK cutoff are presented. HiRes results on composition, searches for anisotropy, measurement of the proton-air total cross-section and shapes of shower profiles are presented.
Redox-controlled proton gating in bovine cytochrome c oxidase.

Cytochrome c oxidase is the terminal enzyme in the electron transfer chain of essentially all organisms that utilize oxygen to generate energy. It reduces oxygen to water and harnesses the energy to pump protons across the mitochondrial membrane in eukaryotes and the plasma membrane in prokaryotes. The mechanism by which proton pumping is coupled to the oxygen reduction reaction remains unresolved, owing to the difficulty of visualizing proton movement within the massive membrane-associated protein matrix. Here, with a novel hydrogen/deuterium exchange resonance Raman spectroscopy method, we have identified two critical elements of the proton pump: a proton loading site near the propionate groups of heme a, which is capable of transiently storing protons uploaded from the negative-side of the membrane prior to their release into the positive side of the membrane and a conformational gate that controls proton translocation in response to the change in the redox state of heme a. These findings form the basis for a postulated molecular model describing a detailed mechanism by which unidirectional proton translocation is coupled to electron transfer from heme a to heme a3, associated with the oxygen chemistry occurring in the heme a3 site, during enzymatic turnover.
Securing frame communication in browsers

Many Web sites embed third-party content in frames, relying on the browser's security policy to protect against malicious content. However, frames provide insufficient isolation in browsers that let framed content navigate other frames. We evaluate existing frame navigation policies and advocate a stricter policy, which we deploy in the open-source browsers. In addition to preventing undesirable interactions, the browser's strict isolation policy also affects communication between cooperating frames. We therefore analyze two techniques for interframe communication between isolated frames. The first method, fragment identifier messaging, initially provides confidentiality without authentication, which we repair using concepts from a well-known network protocol. The second method, postMessage, initially provides authentication, but we discover an attack that breaches confidentiality. We propose improvements in the postMessage API to provide confidentiality; our proposal has been standardized and adopted in browser implementations.
ASYMPTOTIC FILTERING THEORY FOR MULTIVARIATE ARCH MODELS

Abstract ARCH models are widely used to estimate conditional variances and covariances in financial time series models. How successfully can ARCH models carry out this estimation when they are misspecified? How can ARCH models be made robust to misspecification? Nelson and Foster (1994a) employed continuous record asymptotics to answer these questions in the univariate case. This paper considers the general multivariate case. Our results allow us, for example, to construct an asymptotically optimal ARCH model for estimating the conditional variance or conditional beta of a stock return given lagged returns on the stock, volume, market returns, implicit volatility from options contracts, and other relevant data. We also allow for time-varying shapes of conditional densities (e.g., ‘heteroskewticity’ and ‘heterokurticity’). Examples are provided.
Heating of the sunlit polar cap ionosphere by reflected photoelectrons

Photoelectrons escape from the ionosphere on sunlit polar cap field lines. In order for those field lines to carry zero current without significant heavy ion outflow or cold electron inflow, field-aligned potential drops must form to reflect a portion of the escaping photoelectron population back to the ionosphere. Using a 1-D ionosphere-polar wind model and measurements from the Resolute Bay Incoherent Scatter Radar (RISR-N), this paper shows that these reflected photoelectrons are a significant source of heat for the sunlit polar cap ionosphere. The model includes a kinetic suprathermal electron transport solver, and it allows energy input from the upper boundary in three different ways: thermal conduction, soft precipitation, and potentials that reflect photoelectrons. The simulations confirm that reflection potentials of several tens of eV are required to prevent cold electron inflow and demonstrate that the flux tube integrated change in electron heating rate (FTICEHR) associated with reflected photoelectrons can reach 109eV cm−2s−1. Soft precipitation can produce FTICEHR of comparable magnitudes, but this extra heating is divided among more electrons as a result of electron impact ionization. Simulations with no reflected photoelectrons and with downward field-aligned currents (FAC) primarily carried by the escaping photoelectrons have electron temperatures which are ∼250–500 K lower than the RISR-N measurements in the 300–600 km region; however, simulations with reflected photoelectrons, zero FAC, and no other form of heat flux through the upper boundary can satisfactorily reproduce the RISR-N data.
Myopic Marketing Management: Evidence of the Phenomenon and Its Long-Term Performance Consequences in the SEO Context

Managers often have incentives to artificially inflate current-term earnings by cutting marketing expenditures, even if it comes at the expense of long-term profits. Because investors rely on current-term accounting measures to form expectations of future-term profits, inflating current-term results can lead to enhanced current-term stock price. We present evidence that some firms engage in this type of “myopic marketing management” at the time of a seasoned equity offering (SEO). In particular, a greater proportion of firms than is typical report earnings higher than normal and marketing expenditures lower than normal at the time of their SEO. Although they realize that firms might be undertaking strategies to artificially inflate current-term earnings, the financial markets are not adequately identifying and properly valuing the firms doing so. Our results indicate that myopic firms are able to temporarily inflate their stock market valuation, but in the long run, as the consequences of cutting marketing spending become manifest, they have inferior stock market performance. We propose some actions that might reduce the incentives for myopic behavior.
Evidence for p-type doping of InN

The first evidence of successful $p$-type doping of InN is presented. It is shown that $\mathrm{InN}\ensuremath{\mathbin:}\mathrm{Mg}$ films consist of a $p$-type bulk region with a thin $n$-type inversion layer at the surface that prevents electrical contact to the bulk. Capacitance-voltage measurements indicate a net concentration of ionized acceptors below the $n$-type surface. Irradiation with 2 MeV ${\mathrm{He}}^{+}$ ions is used to convert the bulk of $\mathrm{InN}\ensuremath{\mathbin:}\mathrm{Mg}$ from $p$ to $n$-type, at which point photoluminescence is recovered. The conversion is well explained by a model assuming two parallel conducting layers (the surface and the bulk) in the films.
Universally Coupled Massive Gravity, II: Densitized Tetrad and Cotetrad Theories ∗

Einstein’s equations in a tetrad formulation are derived from a linear theory in flat spacetime with an asymmetric potential using free field gauge invariance, local Lorentz invariance and universal coupling. The gravitational potential can be either covariant or contravariant and of almost any density weight. These results are adapted to produce universally coupled massive variants of Einstein’s equations, yielding two one-parameter families of distinct theories with spin 2 and spin 0. The theories derived, upon fixing the local Lorentz gauge freedom, are seen to be a subset of those found by Ogievetsky and Polubarinov some time ago using a spin limitation principle. In view of the stability question for massive gravities, the proven non-necessity of positive energy for stability in applied mathematics in some contexts is recalled. Massive tetrad gravities permit the mass of the spin 0 to be heavier than that of the spin 2, as well as lighter than or equal to it, and so provide phenomenological flexibility that might be of astrophysical or cosmological use.
Shape matching and registration by data-driven EM

In this paper, we present an efficient and robust algorithm for shape matching, registration, and detection. The task is to geometrically transform a source shape to fit a target shape. The measure of similarity is defined in terms of the amount of transformation required. The shapes are represented by sparse-point or continuous-contour representations depending on the form of the data. We formulate the problem as probabilistic inference using a generative model and the EM algorithm. But this algorithm has problems with initialization and computing the E-step. To address these problems, we define a data-driven technique (discriminative model) which makes use of shape features. This gives a hybrid algorithm which combines the generative and discriminative models. The resulting algorithm is very fast, due to the effectiveness of shape-features for solving correspondence requiring only a few iterations. We demonstrate the effectiveness of the algorithm by testing it on standard datasets, such as MPEG7, for shape matching and by applying it to a range of matching, registration, and foreground/background segmentation problems.
Understanding pulmonary gas exchange: ventilation-perfusion relationships.

This essay looks at the historical significance of four APS classic papers that are freely available online: Fenn WO, Rahn H, and Otis AB . A theoretical study of the composition of the alveolar air at altitude. Am J Physiol 146: 637—653, 1946 ( ). Rahn H . A concept of mean alveolar air and the ventilation-bloodflow relationships during pulmonary gas exchange. Am J Physiol 158: 21—30, 1949 ([http://ajplegacy.physiology.org/cgi/reprint/158/1/21][1]). Riley RL and Cournand A . “Ideal” alveolar air and the analysis of ventilation-perfusion relationships in the lungs. J Appl Physiol 1: 825—847, 1949 ( ). Riley RL and Cournand A . Analysis of factors affecting partial pressures of oxygen and carbon dioxide in gas and blood of lungs: theory. J Appl Physiol 4: 77—101, 1951 ( ). [1]: http://ajplegacy.physiology.org/cgi/reprint/158/iss/21
Broadband quasi-taper helical antennas

A unique approach is described for widening the bandwidth of a helical antenna with improved gain, pattern, and axial ratio characteristics. The antenna may be described as a nonuniform or quasi-taper helix, which consists of a combination of uniform and tapered helix sections. Measured patterns, gain, axial ratio, and VSWR for various helical antenna configurations are presented and compared. It is shown that a nonuniform quasi-taper helix can provide an operating bandwidth twice that of a conventional uniform-diameter helix.
Electrochemistry of Mixed Oxygen Ion and Electron Conducting Electrodes in Solid Electrolyte Cells

Mixed ion and electron conductors (MIECs) have garnered increased attention as active components in the electrodes of solid oxide electrolyzers (for electricity to fuel conversion) and especially of solid oxide fuel cells (for fuel to electricity conversion). Although much of the work in the literature is directed toward the understanding of oxygen electroreduction on the surfaces of MIECs, more recent studies also explore the role of these materials in fuel electrooxidation. In both cases, the rich chemical and electronic behaviors of MIECs imply a broad range of possible reaction pathways. We highlight the significant progress that has been made in elucidating these pathways through well-designed experimental and computational studies. At the macroscopic level, patterned electrode studies enable identification of active sites, whereas at the microscopic level, surface-sensitive techniques in combination with atomistic-level simulations are beginning to reveal the nature of the rate-determining step(s) and enable rational design of materials with enhanced activity.
A new interface defect spectroscopy method

A new interface defect spectroscopy method based on variable height charge pumping capable of observing the amphoteric nature of Si/SiO 2 interface states in production quality sub-micron devices is demonstrated. It can help to resolve the long standing debate about the true nature of Si/SiO 2 interface states. Additionally, we show that this is a powerful technique for studying other important material systems.
Thermoelectric properties of silicon nanostructures

Semiconductor nanostructures are promising candidates for efficient thermoelectric energy conversion, with applications in solid-state refrigeration and power generation. The design of efficient semiconductor thermocouples requires a thorough understanding of both charge and heat transport; therefore, thermoelectricity in silicon-based nanostructures requires that both electronic and thermal transport be treated on an equal footing. In this paper, we present semiclassical simulation of carrier and phonon transport in ultrathin silicon nanomembranes and gated nanoribbons. We show that the thermoelectric response of Si-membrane-based nanostructures can be improved by employing the anisotropy of the lattice thermal conductivity, revealed in ultrathin Si due to boundary scattering, or by using a gate to provide additional carrier confinement and enhance the thermoelectric power factor.
Dicyclohexyliodoborane/Triethylamine - a new reagent which achieves the facile enolboration of esters and tertiary amides

Abstract A smooth, rapid, quantitative enolboration of esters and tertiary amides has been achieved for the first time with dicyclohexyliodoborane, Chx2BI, a new reagent in the presence of triethylamine.
A VOTING ARCHITECTURE FOR THE GOVERNANCE OF FREE-DRIVER EXTERNALITIES, WITH APPLICATION TO GEOENGINEERING

Abating climate change is an enormous international public-goods problem with a classical “free-rider” structure. However, it is also a global “free-driver” problem because geoengineering the stratosphere with reflective particles to block incoming solar radiation is so cheap that it could essentially be undertaken unilaterally by one state perceiving itself to be in peril. This exploratory paper develops the main features of a free-driver externality in a simple model motivated by the asymmetric consequences of type-I and type-II errors. I propose a social-choice decision architecture, embodying the solution concept of a supermajority voting rule, and derive its basic properties.
Anti-windup via constrained regulation with observers

Abstract A method is presented for the output-feedback control of discrete-time linear systems with hard constraints on state and control variables. Prior work has shown that optimal controllers for constrained systems take the form of a nonlinear feedback law acting on a set-valued state estimate. In this paper, conventional state estimation schemes are used. A nonlinear control law is derived which views the state estimation error as a disturbance. The resulting control law is then used in conjunction with the conventional observer, rather than set-valued observer, to achieve the desired constrained regulation. The significantly reduced real-time computations come at the cost of restricting the controller structure and thereby introducing possible conservatism in the achievable performance. The results are specialized to the problem of anti-windup for systems with control saturations. A “measurement governor” scheme is introduced that alters plant measurements in such a way to improve performance in the presence of controller saturations.
Ozsváth-Szabó and Rasmussen invariants of doubled knots

Let v be any integer-valued additive knot invariant that bounds the smooth 4-genus of a knot K, |ν(K)| ≤ g 4 (K), and determines the 4-ball genus of positive torus knots, ν(T p,q ) = (p - 1)(q - 1)/2. Either of the knot concordance invariants of Ozsvath-Szabo or Rasmussen, suitably normalized, have these properties. Let D±(K, t) denote the positive or negative t-twisted double of K. We prove that if ν(D + (K,t)) =±1, then ν(D-(K,t)) = 0. It is also shown that ν(D+(K, t)) = 1 for all t ≤ TB(K) and ν(D + (K,t)) = 0 for all t ≥ -TB(-K), where TB(K) denotes the Thurston-Bennequin number. A realization result is also presented: for any 2g x 2g Seifert matrix A and integer a, |a| ≤ g, there is a knot with Seifert form A and v(K) = a.
The Strengths of Near-Infrared Absorption Features Relevant to Interstellar and Planetary Ices

The abundances of ices in planetary environments have historically been obtained through measurements of near-infrared absorption features (λ = 1.0-2.5 μm), and near-IR transmission measurements of materials present in the interstellar medium are becoming more common. For transmission measurements, the band strength (or absorption intensity) of an absorption feature must be known in order to determine the column density of an ice component. In the experiments presented here, we have measured the band strengths of the near-IR absorption features for several molecules relevant to the study of interstellar icy grain mantles and icy planetary bodies: CO (carbon monoxide), CO2 (carbon dioxide), C3O2 (carbon suboxide), CH4 (methane), H2O (water), CH3OH (methanol), and NH3 (ammonia). During a vacuum deposition, the sizes of the near-IR features were correlated with that of a studied mid-IR feature whose strength is well known from previous ice studies. These data may be used to determine ice abundances from observed near-IR spectra of interstellar and planetary materials or to predict the sizes of near-IR features in spectral searches for these molecules in astrophysical environments.
AN ELEMENTARY AND CONSTRUCTIVE SOLUTION TO HILBERT'S 17TH PROBLEM FOR MATRICES

We give a short and elementary proof of a theorem of Procesi, Schacher and (independently) Gondard, Ribenboim that generalizes a famous result of Artin. Let A be an n x n symmetric matrix with entries in the polynomial ring R[x 1 ,..,x m ]. The result is that if A is positive semidefinite for all substitutions (x 1 ,...,x m ) ∈ R m , then A can be expressed as a sum of squares of symmetric matrices with entries in R(x 1 ,...,x m ). Moreover, our proof is constructive and gives explicit representations modulo the scalar case.
Economic Crisis and Income Inequality in Korea

Using quarterly data for urban worker-households in Korea, I investigate trends in income and consumption inequality since the eruption of the recent economic crisis. I find evidence of sharply increasing income inequality while consumption inequality does not show any apparent trend. There is also evidence that severe deterioration in between(income-decile)group inequality has more than offset minor improvement in within-group inequality, resulting in deterioration of overall income inequality. It is, therefore, believed that the worker households in Korea are undergoing a distinct process of income stratification parallel with the concentration of income after the economic crisis.
Climate Change in the South American Monsoon System: Present Climate and CMIP5 Projections

AbstractThe South American monsoon system (SAMS) is the most important climatic feature in South America. This study focuses on the large-scale characteristics of the SAMS: seasonal amplitudes, onset and demise dates, and durations. Changes in the SAMS are investigated with the gridded precipitation, Climate Forecast System Reanalysis (CFSR), and the fifth phase of the Coupled Model Intercomparison Project (CMIP5) simulations for two scenarios [“historical” and high-emission representative concentration pathways (rcp8.5)]. Qualitative comparisons with a previous study indicate that some CMIP5 models have significantly improved their representation of the SAMS relative to their CMIP3 versions. Some models exhibit persistent deficiencies in simulating the SAMS. CMIP5 model simulations for the historical experiment show signals of climate change in South America. While the observational data show trends, the period used is too short for final conclusions concerning climate change. Future changes in the SAMS ...
Explicit nonflat time evolution for PDE-Based image restoration

This article is concerned with new strategies with which explicit time-stepping procedures of PDE-based restoration models converge with a similar efficiency to implicit algorithms. Conventional explicit algorithms often require hundreds of iterations to converge. In order to overcome the difficulty and to further improve image quality, the article introduces new spatially variable constraint term and timestep size, as a method of nonflat time evolution (MONTE). It has been verified that the explicit time-stepping scheme incorporating MONTE converges in only 4-15 iterations for all restoration examples we have tested. It has proved more effective than the additive operator splitting (AOS) method in both computation time and image quality (measured in PSNR), for most cases. Since the explicit MONTE procedure is efficient in computer memory, requiring only twice the image size, it can be applied particularly for huge data sets with a great efficiency in computer memory as well.
Can Exchange Rates Forecast Commodity Prices

We show that “commodity currency” exchange rates have surprisingly robust power in predicting global commodity prices, both in-sample and out-of-sample, and against a variety of alternative benchmarks. This result is of particular interest to policy makers, given the lack of deep forward markets in many individual commodities, and broad aggregate commodity indices in particular. We also explore the reverse relationship (commodity prices forecasting exchange rates) but find it to be notably less robust. We offer a theoretical resolution, based on the fact that exchange rates are strongly forward-looking, whereas commodity price fluctuations are typically more sensitive to short-term demand imbalances.
SUSTAINABILITY OF THE US CURRENT ACCOUNT DEFICIT: AN ECONOMETRIC ANALYSIS OF THE IMPACT OF CAPITAL INFLOW ON DOMESTIC ECONOMY

The purpose of this paper is to estimate, by using the recent econometric techniques of unit root testing and Johansen-Juselius cointegration technique (1990), the impact of foreign capital inflow ...
Protocol conformance testing using multiple UIO sequences

Automatic generation of conformance test sequences for communication protocols by means of unique input/output (UIO) sequences is addressed. It is shown that if multiple minimum-length UIO sequences are computed for each state of the finite-state-machine (FSM) specification, then the length of the resulting test sequence is significantly reduced without an appreciable increase in the time needed to compute the sequence. An algorithm for assignment of the multiple UIO sequences is given. This algorithm, which is based on network flow, is polynomial in the number of states and transitions of the FSM and is effective in reducing the overall length of the test sequence. >
Room-temperature Hiyama cross-couplings of arylsilanes with alkyl bromides and iodides.

The first method for achieving Hiyama couplings of unactivated alkyl bromides and iodides is reported. The desired carbon−carbon bond formation proceeds under mild conditions (room temperature) with good functional-group tolerance.
From Gauge-string duality to strong interactions: A Pedestrian's guide

We survey recent progress in relating string theory to quantum chromodynamics (QCD), focusing on (a) holographic models of gauge theories that are similar to QCD and (b) applications to heavy-ion collisions.
Bacterial symbionts and natural products

The study of bacterial symbionts of eukaryotic hosts has become a powerful discovery engine for chemistry. This highlight looks at four case studies that exemplify the range of chemistry and biology involved in these symbioses: a bacterial symbiont of a fungus and a marine invertebrate that produce compounds with significant anticancer activity, and bacterial symbionts of insects and nematodes that produce compounds that regulate multilateral symbioses.
Locally Decodable Codes for Edit Distance

Locally decodable codes (LDC) [1,9] are error correcting codes that allow decoding (any) individual symbol of the message, by reading only few symbols of the codeword. LDC’s, originally considered in the setting of PCP’s [1], have found other additional applications in theory of CS, such as PIR in cryptography, generating a lot of fascinating work (see [12] and references within). In one straightforward practical application to storage, such codes provide enormous efficiency gains over standard error correcting codes (ECCs), that need to read the entire encoded message to learn even a single bit of the encoded message. Typically, LDC’s, as well as standard ECC’s are designed to decode the encoded message if up to some bounded fraction of the symbols had been modified. This corresponds to decoding strings of bounded Hamming distance from a valid codeword. A stronger natural metric is the edit distance, measuring the shortest sequence of insertions and deletions (indel.) of symbols leading from one word to another. Standard ECC’s for edit distance have been previously considered [11]. Furthermore, [11] devised codes with rate and distance (error tolerance) optimal up to constants, with efficient encoding and decoding procedures. However, combining these two useful settings of LDC, and robustness against indel. errors has never been considered.
Alcohol Use Disorders: Tracts, Twins, and Trajectories

gray matter reduction in the cortical lateral frontal and temporal lobes and attenuated white matter growth of the corpus callosum and pons relative to nondrinking control subjects. In a study by Ruggeri et al. (2), alcohol use disorders were associated with hypermethylation in the 3:-protein-phosphatase-1G (PPM1G )g ene locus; more specifically, PPM1G hypermethylation was associated with the escalation of alcohol use, increased impulsiveness, and increased activity in the right subthalamic nucleus. How are thesetwoobservations—oneonneurocircuitryimagingchanges in adolescents and one on protein phosphatase methylation in adolescents—related? Theadolescentbrainundergoeswidespreadchangesinform and function, both within individual regions and in the connections betweenthem. Studies have shown that a reduction of cortical gray matter begins in preadolescence and continues into the mid-20s, possibly reflecting a normal pruning process(3,4).Equallycompellingaredatashowingthatwhite matter volume increases over the course of adolescence, presumably reflecting connectivity changes, including axonal extension and myelination (4). Mounting evidence suggests that the complex changes underlying neurodevelopment render the adolescent brain particularly vulnerable to the deleterious effects of alcohol. Heavy alcohol use during adolescence is associated with a range of neurobehavioral sequelae, including impairments in visuospatial processing, attention, and memory (5,6)andanincreased riskfor future alcoholuse disorders.
IRM: Integrated File Replication and Consistency Maintenance in P2P Systems

In peer-to-peer file sharing systems, file replication and consistency maintenance are widely used techniques for high system performance. Despite significant interdependencies between them, these two issues are typically addressed separately. Most file replication methods rigidly specify replica nodes, leading to low replica utilization, unnecessary replicas and hence extra consistency maintenance overhead. Most consistency maintenance methods propagate update messages based on message spreading or a structure without considering file replication dynamism, leading to inefficient file update and hence high possibility of outdated file response. This paper presents an Integrated file Replication and consistency Maintenance mechanism (IRM) that integrates the two techniques in a systematic and harmonized manner. It achieves high efficiency in file replication and consistency maintenance at a significantly low cost. Instead of passively accepting replicas and updates, each node determines file replication and update polling by dynamically adapting to time-varying file query and update rates, which avoids unnecessary file replications and updates. Simulation results demonstrate the effectiveness of IRM in comparison with other approaches. It dramatically reduces overhead and yields significant improvements on the efficiency of both file replication and consistency maintenance approaches.
A Note on Polarization Vectors in Quantum Electrodynamics

A photon of momentum k can have only two polarization states, not three. Equivalently, one can say that the magnetic vector potential A must be divergence-free in the Coulomb gauge. These facts are normally taken into account in QED by introducing two polarization vectors ɛλ(k) with λ ∈ {1,2}, which are orthogonal to the wave-vector k. These vectors must be very discontinuous functions of k and, consequently, their Fourier transforms have bad decay properties. Since these vectors have no physical significance there must be a way to eliminate them and their bad decay properties from the theory. We propose such a way here.
A beam size monitor based on appearance intensities for multiple gas ionization

A method of measuring the spot size or bunch length of intense charged particle beams is proposed. The relation between the size (widths and length) of a charged particle beam and the beam's electric field forms the basis for a sub-micron beam size monitor. When the beam passes through a low pressure gas of high Z atoms, the beam field causes multiple ionizations of the gas atoms. The appearance of ionized atoms in a given charge state gives information about the field of the beam and hence its size. Sample calculations show that appearance thresholds can indicate the spot size of round beams with 10 nm accuracy or the bunch length of round or flat beams with up to 10 /spl mu/m accuracy.
Nonparametric Bayesian Estimation of Freeway Capacity Distribution from Censored Observations

Previous studies have been made of the usefulness and effectiveness of survival analysis in transportation and traffic engineering studies with incomplete data in which the Kaplan-Meier estimate is proposed for determining traffic capacity distribution. However, well-known estimators like Kaplan-Meier and Nelson-Aalen have several disadvantages that make it difficult to obtain the traffic capacity distribution. First, neither estimator is defined for all values of traffic flows possible. That is, the maximum flow followed by a breakdown defines the final point of the estimated distribution curve. Therefore, parametric fitting tools have to be applied to obtain the remaining portion of the curve. Moreover, the discontinuity and nonsmoothness of the Kaplan-Meier and Nelson-Aalen estimates make it difficult to ensure the robustness of the estimation. In this paper the Kaplan-Meier and Nelson-Aalen nonparametric estimators are used to obtain the traffic capacity function of four freeway sections. Then a Bayes...
Frequency Acceleration of Voltage Endurance

Frequency acceleration of voltage endurance has been the subject of a large number of research papers. A review of those papers reveals that it is not a priori possible to rely upon obtianing linearity of acceleration. It is shown that the appropriate acceleration factor for micaceous insulation can only be determined with very long term testing.
Natural Dark Matter from an unnatural Higgs boson and new colored particles at the TeV scale

The thermal relic abundance of Dark Matter motivates the existence of new electroweak scale particles, independent of naturalness considerations. However, most un- natural Dark Matter models do not ensure the presence of new particles charged under SU(3)C, resulting in challenging LHC phenomenology. Here, we present a class of models with scalar electroweak doublet Dark Matter that require a host of colored particles at the TeV scale. In these models, the Higgs boson is apparently fine-tuned, but the Dark Matter doublet is kept light without any additional fine-tuning.
Intellectual Property Rights and Innovation: Evidence from the Human Genome

Do intellectual property (IP) rights on existing technologies hinder subsequent innovation? Using newly collected data on the sequencing of the human genome by the public Human Genome Project and the private firm Celera, this paper estimates the impact of Celera’s gene-level IP on subsequent innovation. Across a range of empirical specifications, I document evidence that Celera’s IP led to reductions in subsequent scientific research and product development on the order of 20–30 percent. These results suggest that Celera’s short-term IP had persistent negative effects on subsequent innovation relative to a counterfactual of Celera genes having always been in the public domain.