cssi/SciSciGPT-SciSciNet huggingface dataset:
Advanced Compton telescope designs and sn science

Abstract The Advanced Compton Telescope (ACT) has been suggested to be the optimal next-generation instrument to study nuclear gamma-ray lines. In this work, we investigate the potential of three hypothetical designs of the ACT to perform SN science. We provide estimates of: (1) the SN detection rate, (2) the SN Ia discrimination rate, and (3) which gamma-ray lines would be detected from specific supernova remnants. We find that the prompt emission from a SN Ia is such that it is unlikely that one would be within the range that an INTERMEDIATE ACT would be able to distinguish between explosion scenarios, although such an instrument would detect a handful of SNRs. We further find that the SUPERIOR ACT design would be a truly breakthrough instrument for SN science. By supplying these estimates, we intend to assist the gamma-ray astrophysics community in deciding the course of the next decade of gamma-ray SN science.
Explicit examples of extremal quasiconvex quadratic forms that are not polyconvex

We prove that if the associated fourth order tensor of a quadratic form has a linear elastic cubic symmetry then it is quasiconvex if and only if it is polyconvex, i.e. a sum of convex and null-Lagrangian quadratic forms. We prove that allowing for slightly less symmetry, namely only cyclic and axis-reflection symmetry, gives rise to a class of extremal quasiconvex quadratic forms, that are not polyconvex. Non-affine boundary conditions on the potential are identified which allow one to obtain sharp bounds on the integrals of these extremal quasiconvex quadratic forms of $$\nabla u$$ over an arbitrary region.
Numerical evidences of fractionalization in an easy-axis two-spin heisenberg antiferromagnet.

Based on exact numerical calculations, we show that the generalized kagome spin model in the easy-axis limit exhibits a spin liquid, topologically degenerate ground state over a broad range of phase space, including a point at which the model is equivalent to a Heisenberg model with purely two-spin exchange interactions. We further present an explicit calculation of the gap (and dispersion) of ``vison'' excitations, and exponentially decaying spin and vison two-point correlators. These are hallmarks of deconfined, fractionalized, and gapped spinons. The nature of the phase transition from the spin-liquid state to a magnetic ordered state tuned by a negative four-spin ``potential'' term is also discussed in light of the low energy spectrum. These results greatly expand the range and the theoretical view of the spin-liquid phase in the vicinity of the Rokhsar and Kivelson exactly soluble point.
Trans-Substituted porphyrin building blocks bearing iodo and ethynyl groups for applications in bioorganic and materials chemistry

Abstract The modular synthesis of linear or cyclic multiporphyrin arrays relies on the availability of trans -substituted porphyrin building blocks with high solubility in organic solvents. Eleven porphyrin building blocks were synthesized bearing iodo, ethynyl, and 2-(trimethylsilyl)ethynyl groups at the 4-, 3-, or 3,5-positions of two meso -aryl units, and mesityl groups at the other two meso -positions. The synthesis involves condensation of 5-mesityldipyrromethane with one or two aryl aldehydes. Combinations of functional groups include di-iodo, tetra-iodo, bis[(2-(trimethylsilyl)ethynyl], iodo and 2-(trimethylsilyl)ethynyl, and ethynyl and 2-(trimethylsilyl)ethynyl. In addition, a porphyrin bearing one 4-iodophenyl group and one 3,5-bis(boron-dipyrrin)phenyl group was synthesized for applications in molecular photonic devices. The iodo and ethynyl groups are ideally-suited for Pd-mediated coupling reactions, allowing the porphyrin building blocks to be joined in the systematic construction of soluble multiporphyrin arrays.
Lower bounds for linear degeneracy testing

In the late nineties, Erickson proved a remarkable lower bound on the decision tree complexity of one of the central problems of computational geometry: given n numbers, do any r of them add up to 0? His lower bound of Ω(n⌈r/2⌉), for any fixed r, is optimal if the polynomials at the nodes are linear and at most r-variate. We generalize his bound to s-variate polynomials for s > r. Erickson's bound decays quickly as r grows and never reaches above pseudo-polynomial: we provide an exponential improvement. Our arguments are based on three ideas: (i) a geometrization of Erickson's proof technique; (ii) the use of error-correcting codes; and (iii) a tensor product construction for permutation matrices.
Folding energetics in thin-film diaphragms

We perform experiments to elucidate how the folding patterns of thin-film diaphragms subject to in-plane isotropic and anisotropic compressive strains depend on the shape, thickness and size of the diaphragms. We then use a constrained von Kaarmaan model to relate the experimental results to the energetics of folding. We show that the differences between the isotropic and the anisotropic cases can be traced back to the structure of the membraneous energy density function. In the isotropic case, we find foldings which satisfy the boundary conditions and minimize the membraneous energy. In the anisotropic case, no such foldings exist, but we are able to construct sequences of increasingly fine foldings which satisfy the boundary conditions and whose membraneous energies converge to the infimum. In both cases, we obtain solutions by allowing bending to select a preferred folding. The solutions compare well with the experimental observations.
The Implications of a High Cosmic-Ray Ionization Rate in Diffuse Interstellar Clouds

Diffuse interstellar clouds show large abundances of H+ 3 which can only be maintained by a high ionization rate of H2. Cosmic rays are the dominant ionization mechanism in this environment, so the large ionization rate implies a high cosmic-ray flux, and a large amount of energy residing in cosmic rays. In this paper, we find that the standard propagated cosmic-ray spectrum predicts an ionization rate much lower than that inferred from H+ 3. Low-energy (~10 MeV) cosmic rays are the most efficient at ionizing hydrogen, but cannot be directly detected; consequently, an otherwise unobservable enhancement of the low-energy cosmic-ray flux offers a plausible explanation for the H+ 3 results. Beyond ionization, cosmic rays also interact with the interstellar medium by spalling atomic nuclei and exciting atomic nuclear states. These processes produce the light elements Li, Be, and B, as well as gamma-ray lines. To test the consequences of an enhanced low-energy cosmic-ray flux, we adopt two physically motivated cosmic-ray spectra which by construction reproduce the ionization rate inferred in diffuse clouds, and investigate the implications of these spectra on dense cloud ionization rates, light-element abundances, gamma-ray fluxes, and energetics. One spectrum proposed here provides an explanation for the high ionization rate seen in diffuse clouds while still appearing to be broadly consistent with other observables, but the shape of this spectrum suggests that supernovae remnants may not be the predominant accelerators of low-energy cosmic rays.
Identification and purification of a soluble adenosine triphosphatase from Tetrahymena pyriformis .

An unusual ATPase isolated from the postribosomal supernatant fraction of Tetrahymena pyriformis has been purified to homogeneity. The purification procedure consisted of protamine sulfate and heat treatment; column chromatography successively on phosphocellulose, DEAE-cellulose and Sephadex G-150; and isoelectric focusing. The pure enzyme has a molecular weight of 89,000 and requires either Ca2+ or Ba2+ for maximum activation. Nucleoside triphosphates are hydrolized at decreasing rates in the order: ATP > GTP > ITP > CTP > UTP. The Km for ATP is 2.5 mM. Because of its properties the enzyme is tentatively classified as a soluble Ca2+-activated ATPase.
Reconstructing a history of recombinations from a set of sequences

Abstract One of the classic problems in computational biology is the reconstruction of evolutionary history. A recent trend in the area is to increase the explanatory power of the models that are considered by incorporating higher-order evolutionary events that more accurately reflect the mechanisms of mutation at the level of the chromosome. We take a step in this direction by considering the problem of reconstructing an evolutionary history for a set of genetic sequences that have evolved by recombination. Recombination is a non-tree-like event that produces a child sequence by crossing two parent sequences. We present polynomial-time algorithms for reconstructing a parsimonious history of such events for several models of recombination when all sequences, including those of ancestors, are present in the input. We also show that these models appear to be near the limit of what can be solved in polynomial time, in that several natural generalizations are NP-complete.
Ramanujan's "Lost Notebook" and the Virasoro Algebra

By using the theory of vertex operator algebras, we gave a new proof of the famous Ramanujan’s modulus 5 modular equation from his ‘‘Lost Notebook’’ (p. 139 in [R]). Furthermore, we obtained an infinite list of q-identities for all odd moduli; thus, we generalized the result of Ramanujan.
Resolved inner disks around Herbig Ae/Be stars

We have observed 14 Herbig Ae/Be (HAEBE) sources with the long-baseline near-IR Palomar Testbed Interferometer. All except two sources are resolved at 2.2 μm, with angular sizes generally 5 mas. We determine the size scales and orientations of the 2.2 μm emission using various models: uniform disks, Gaussians, uniform rings, flat accretion disks with inner holes, and flared disks with puffed-up inner rims. Although it is difficult to distinguish different radial distributions, we are able to place firm constraints on the inclinations of most sources; seven objects display significantly inclined morphologies. The inner disk inclinations derived from our near-IR data are generally compatible with the outer disk geometries inferred from millimeter interferometric observations, implying that HAEBE disks are not significantly warped. Using the derived inner disk sizes and inclinations, we compute the spectral energy distributions (SEDs) for two simple physical disk models and compare these with observed SEDs compiled from the literature and new near-IR photometry. While geometrically flat accretion disk models are consistent with the data for the earliest spectral types in our sample (MWC 297, V1685 Cyg, and MWC 1080), the later type sources are explained better through models incorporating puffed-up inner disk walls. The different inner disk geometries may indicate different accretion mechanisms for early- and late-type HAEBE stars.
Evaluation of Peripheral Visual Performance When Using Incandescent and LED Miner Cap Lamps

Illumination plays a critical role in an underground miner's safety because miners depend most heavily on visual cues to recognize hazards. Mobile mining machinery, located in the miner's peripheral field of view ( plusmn10deg to about plusmn60deg off-axis), may pose potential pinning and striking hazards. The main objective of this research was to determine if there were peripheral visual performance improvements for the detection of moving objects when using cool-white light-emitting diode (LED) cap lamps as compared to incandescent (INC) light bulbs commonly used in miner cap lamps. The cap lamp variable of interest is the spectral power distribution. The illuminances were normalized by a diffusion filter. The second objective was to determine if age is a factor for the peripheral visual performance. This is important because the workforce is aging-the average miner age is about 43 years old. Thirty subjects participated in the study, ten subjects each in the age groups of younger (18-25 years), middle (40-50 years), and older (51+ years). Visual performance was quantified by the subjects' speed and accuracy of response to detect the rotation of high-contrast (white) circular targets located 3.83 m away at -20deg, 40deg, and 50deg off-axis. The speed of detection and the number of missed target rotations (accuracy) were measured. The prototype LED cap lamp results were best with an 11%-15% improvement compared to the INC and LED cap lamps, respectively. Age does appear to be a significant factor. For the middle and older age groups, the target movement detection time increased 75% and 60%, and the number of missed targets increased 500% and 450%, respectively, in comparison to the youngest age group. The results also suggest that target location is a significant factor. The subjects' target movement detection time for the 40deg and 50deg target movements increased 16% and 69%, respectively, as compared to the -20deg target.
Efficient debugging in a formal verification environment

In this paper, we emphasize the importance of efficient debugging in formal verification and present capabilities that we have developed in order to aid debugging in Intel’s Formal Verification Environment. We have given the name “Counter-Example Wizard” to the bundle of capabilities that we have developed to address the needs of the verification engineer in the context of counter-example diagnosis and rectification. The novel features of the Counter-Example Wizard are the multi-value counter-example annotation, constraint-based debugging, and multiple counter-example generation mechanisms. Our experience with the verification of real-life Intel designs shows that these capabilities complement one another and can help the verification engineer diagnose and fix a reported failure. We use real-life verification cases to illustrate how our system solution can significantly reduce the time spent in the loop of model checking, specification, and design modification.
Pilot-Induced Oscillations Involving Multiple Nonlinearities

A pilot-induced oscillation is a type of instability caused by dynamic couplingbetween the pilot and the aircraft. Linear system analysis reveals that the pilot/aircraft system is unstable during the oscillation event. However, nonlinearities in the feedback system can limit the response variables so that a sustained, constant amplitude limit cycle results. A method is presented to analyze the limit cycle behavior of pilot/aircraft systems as a means of understanding pilot-inducedoscillations and their causes. A new computationaltechnique is considered and a new methodof testing limit cycle stability is presented. An analysisof the YF-12 pilot-inducedoscillation characteristics is used to demonstrate the method.
Absolute instabilities in gyropeniotron amplifiers

The electrons in a gyropeniotron transfer their rotational energy through the transverse migration toward the ridges or the vanes of the waveguide without any orbital bunching. A slotted waveguide (magnetron type) is used for enhanced interaction impedance at high cyclotron harmonics even with low-energy beam and for better mode control. The number of vanes required is 2(s+1) where s is the cyclotron harmonic number of the gyropeniotron interaction. We have calculated the critical current, oscillation frequency, and characteristic wave number for the excitation of absolute instability in gyropeniotron amplifiers. We found that the threshold current decreases as (alpha) increases (at fixed beam voltage) where (alpha) is the ratio of the perpendicular velocity to the parallel velocity of an electron.
Cosmological stretching of perturbations on a cosmic string

We investigate the effects of cosmological expansion on the spectrum of small-scale structure on a cosmic string. We simulate the evolution of a string with two modes that differ in wavelength by one order of magnitude. Once the short mode is inside the horizon, we find that its physical amplitude remains unchanged, in spite of the fact that its comoving wavelength decreases as the longer mode enters the horizon. Thus the ratio of amplitude to wavelength for the short mode becomes larger than it would be in the absence of the long mode.
Energy Prices and the Adoption of Energy‐Saving Technology*

This article investigates the link between factor prices, technology and factor demands. Using plant-level data from the Census of Manufactures, I compare the energy intensity of entrants and incumbents from 1967–97. A 10% increase in the price of energy reduces the relative energy intensity of entrants by 1%. The estimate implies that technology adoption by incumbents explains a statistically significant but relatively small fraction of changes in aggregate energy demand in the 1970s and 1980s. Furthermore, entrants’ technology adoption can reduce the long run effect of energy prices on growth, but by less than previous research has found.
Equal sacrifice and incentive compatible income taxation

Abstract The concepts of equal sacrifice and incentive compatibility in income taxation have been of interest to economists for some time. Here we attempt to integrate the two literatures in a model that offers a labor-leisure choice to consumers while imposing an equal relative or absolute sacrifice tax system. The main result is that equal sacrifice incentive compatible income tax systems generally exist and are locally unique. Examples are presented where this tax system is easy to compute. Comparative statics are calculated. Finally, some remarks about the welfare properties of these tax systems are made.
The conformal plate buckling equation

The linear equation Δ 2 u = 1 for the infinitesimal buckling under uniform unit load of a thin elastic plate over R 2 has the particularly interesting nonlinear generalization Δ g 2 u = 1, where Ag = e -2u Δ is the Laplace-Beltrami operator for the metric g = e 2u g 0 , with g 0 the standard Euclidean metric on R 2 . This conformal elliptic PDE of fourth order is equivalent to the nonlinear system of elliptic PDEs of second order Δu(x) + K g (x) exp(2u(x)) = 0 and ΔK g (x) + exp(2u(x)) = 0, with x ∈ R 2 , describing a conformally flat surface with a Gauss curvature function K g that is generated self-consistently through the metric's conformal factor. We study this conformal plate buckling equation under the hypotheses of finite integral curvature f Kg exp(2u) dx = K, finite area ∫ exp(2u) dx = a, and the mild compactness condition K + ∈ L 1 (B 1 (y)), uniformly with respect to y ∈ R 2 . We show that asymptotically for |x| → ∞, all solutions behave like u(x) = -(κ/2π) ln |x| + C + o(1) and K(x) = -(α/2π) ln |x| + C + o(1), with κ ∈ (2π, 4π) and α = √2κ(4π - κ). We also show that for each K ∈ (2π, 4π), there exists a K * and a radially symmetric solution pair u, K satisfying K(u) = K and max K = K * , which is unique modulo translation of the origin and scaling of x coupled with a translation of u.
Theoretical chemical characterization of energetic materials

Our research is focused on developing computational capabilities for the prediction of properties of energetic materials associated with performance and sensitivity. Additionally, we want to identify and characterize the dynamic processes that influence conversion of an energetic material to products upon initiation. We are attempting to achieve these goals through the use of standard atomistic simulation methods. In this paper, various theoretical chemistry methods and applications to energetic materials will be described. Current capabilities in predicting structures, thermodynamic properties, and dynamic behavior of these materials will be demonstrated. These are presented to exemplify how information generated from atomistic simulations can be used in the design, development, and testing of new energetic materials. In addition to illustrating current capabilities, we will discuss limitations of the methodologies and needs for advancing the state of the art in this area.
Cytologic diagnosis of bronchogenic carcinoma.

SUMMARY Our experience with cytologic diagnosis of bronchogenic carcinoma has been summarized. To date in more than 400 cases of bronchogenic carcinoma the diagnosis has been made cytologically with a false positive error of approximately 2 per cent. In our experience the false negative error has been approximately 30 per cent. Of 80 consecutive surgically removed bronchogenic carcinomas, 10 per cent were peripherally placed showing slight or no gross communication with the bronchial tree. Cytologic examination in the case of these peripherally located tumors gave negative results. Cytologic studies are of value in the diagnosis of alveolar-cell tumor but of no value in bronchial adenoma or cylindroma.
Noncommuting fields and non-Abelian fluids

Abstract The original ideas about noncommuting coordinates are recalled. The connection between U(1) gauge fields defined on noncommuting coordinates and fluid mechanics is explained. Non-Abelian fluid mechanics is described.
Complexity lower bounds for computation trees with elementary transcendental function gates

We consider computation trees which admit as gate functions along with the usual arithmetic operations also algebraic or transcendental functions like exp, log, sin, square root (defined in the relevant domains) or much more general Pfaffian functions. A new method for proving lower bounds on the depth of these trees is developed which allows to prove a lower bound Ω(√log N) for testing membership to a convex polyhedron with N facets of all dimensions, provided that N is large enough.
An ideal free distribution explains the root production of plants that do not engage in a tragedy of the commons game

Summary Below-ground competition is intense and may dramatically reduce plant performance. However, there is still no consensus on the best strategies plants should use to maximize competitive ability in soil. Some suggest plants should grow roots according to nutrient availability, while others suggest plants should grow roots taking into account both nutrients and neighbours. Unambiguously, testing between these two alternative hypotheses has been challenging. This manuscript had three objectives. First, we presented a model of root growth under competition that is based on an ideal free distribution (IFD). Secondly, we develop the concept of the best response curve as a tool for clearer experimental tests of plant responses to neighbours. Thirdly, we test these ideas by growing fast cycling Brassica rapa either alone or with neighbours to examine this species' root growth strategy both alone and under competition. We hypothesize that those plants with no direct response to neighbours should grow roots according to an IFD. This means that if plants produce x roots in a soil volume of quality R, they should produce x/n roots in a soil volume of quality R/n. The experimental data were consistent with this prediction. Growing plants with neighbours was statistically identical to growing them with half as many nutrients. Thus, the only effect of neighbours was to reduce nutrient availability. This model provides an alternative to previous game theoretic models and suggests an experimental protocol based on the concept of the best response curve. We hope that testing the game theoretic model with a clear alternative model will guide experiment and debate. Synthesis. The data in the literature are mixed, with species sometimes responding to nutrients only, and sometimes responding interactively to both nutrients and neighbours. At present, we lack a general understanding of the causes or consequences of this diversity of strategies. We suggest that a greater understanding of trade-offs among traits that are important for other biotic interactions (above-ground competition, enemy defence, mutualisms) will lead to a greater understanding of why some species over-proliferate roots when in competition but other species do not.
Evaluation of pretreatment computed tomography as a predictor of local control in T1/T2 pyriform sinus carcinoma treated with definitive radiotherapy.

Background This study was undertaken to determine whether pretreatment computed tomography (CT) findings can predict local control in pyriform sinus carcinoma treated with definitive radiotherapy (RT). Methods Twenty-three patients with pyriform sinus carcinoma (T1: n = 5; T2: n = 18) were treated with high-dose RT and followed for a minimum of 2 years. Tumor volumes and extent were determined on pretreatment CT studies. The specific CT parameters assessed were analyzed as predictors of local control. Results There was a significant decrease in local control rate for tumors over 6.5 mL (1 of 4 [25%]) relative to tumors under 6.5 mL (17 of 19 [89%]; p = .021). Sensitivity and specificity for local control using this cutoff were 94% and 60%, respectively. Tumor score, as a measure of anatomic extent, was also found to be a significant predictor of local control (p = .033). The local control rate was not influenced significantly by the presence of “minimal” apex disease (<10 mm in greatest dimensions as measured on CT) but decreased significantly when “bulk” apex disease (≥10 mm) was present (p = .027). Laryngeal cartilage sclerosis was not a significant predictor of outcome. Conclusion Computed tomography can stratify pyriform sinus carcinomas into groups more or less likely to be locally controlled with definitive RT. © 1998 John Wiley & Sons, Inc. Head Neck20: 159–168, 1998.
The oblique orbit of the super-Neptune HAT-P-11b

We find the orbit of the Neptune-sized exoplanet HAT-P-11b to be highly inclined relative to the equatorial plane of its host star. This conclusion is based on spectroscopic observations of two transits, which allowed the Rossiter–McLaughlin effect to be detected with an amplitude of 1.5m s^(−1). The sky-projected obliquity is 103^(+26) _(−10) deg. This is the smallest exoplanet for which spin–orbit alignment has been measured. The result favors a migration scenario involving few-body interactions followed by tidal dissipation. This finding also conforms with the pattern that the systems with the weakest tidal interactions have the widest spread in obliquities.We predict that the high obliquity of HAT-P-11 will be manifest in transit light curves from the Kepler spacecraft: starspot-crossing anomalies will recur at most once per stellar rotation period, rather than once per orbital period as they would for a well-aligned system.
Generalized Greatest Common Divisors, Divisibility Sequences, and Vojta¿s Conjecture for Blowups

We apply Vojta?s conjecture to blowups and deduce a number of deep statements regarding (generalized) greatest common divisors on varieties, in particular on projective space and on abelian varieties. Special cases of these statements generalize earlier results and conjectures. We also discuss the relationship between generalized greatest common divisors and the divisibility sequences attached to algebraic groups, and we apply Vojta?s conjecture to obtain a strong bound on the divisibility sequences attached to abelian varieties of dimension at least two.
Improved Materials for DC Dynamic Scattering at Elevated Temperatures

Abstract Liquid crystal (LC) mixtures and a sealant suitable for dc-activated dynamic scattering (DS) matrix displays are developed for wide range storage temperature (−60 to 80°C) and for elevated temperature operation. Three improved eutectic nematic mixtures are formulated with nematic ranges (undoped) of 0 to 74, −;4 to 82, and −13 to 78°C, with flow viscosities of 31, 32 and 36 cP respectively at 25°C. Several types of sealants are tested in contact with LC and are evaluated according to the level of contamination they introduce at elevated temperature. One UV-curved sealant shows no apparent degradation effects after more than 1800 hours of 100°C heating with an undoped ester LC in a vacuum-filled test cell made with this sealant. Thermal storage stability at 80°C and low temperature stability at −60°C in such sealed cells show little change in surface alignment, resistivity, and DS characteristics in LCs with redox dopants, namely dialkylferrocene and (2,4,7-trinitro-9-fluorenylidene)-malononitrile...
Large Magellanic Cloud Microlensing Optical Depth with Imperfect Event Selection

I present a new analysis of the MACHO Project 5.7 yr Large Magellanic Cloud (LMC) microlensing data set that incorporates the effects of contamination of the microlensing event sample by variable stars. Photometric monitoring of MACHO LMC microlensing event candidates by the EROS and OGLE groups has revealed that one of these events is likely to be a variable star, while additional data have confirmed that many of the other events are very likely to be microlensing. These additional data on the nature of the MACHO microlensing candidates are incorporated into a simple likelihood analysis to derive a probability distribution for the number of MACHO microlens candidates that are true microlensing events. This analysis shows that 10-12 of the 13 events that passed the MACHO selection criteria are likely to be microlensing events, with the other 1-3 being variable stars. This likelihood analysis is also used to show that the main conclusions of the MACHO LMC analysis are unchanged by the variable star contamination. The microlensing optical depth toward the LMC is τ = × 10-7. If this is due to microlensing by known stellar populations plus an additional population of lens objects in the Galactic halo, then the new halo population would account for 16% of the mass of a standard Galactic halo. The MACHO detection exceeds the expected background of two events expected from ordinary stars in standard models of the Milky Way and LMC at the 99.98% confidence level. The background prediction is increased to three events if maximal disk models are assumed for both the Milky Way and LMC, but this model fails to account for the full signal seen by MACHO at the 99.8% confidence level.
MASSES AND DISTANCE OF THE YOUNG BINARY NTTS 045251+3016

As part of our continuing campaign to measure the masses of pre-main-sequence (PMS) stars dynamically and thus to assess the reliability of the discrepant theoretical calculations of contraction to the main sequence, we present new results for NTTS 045251+3016, a visual and double-lined spectroscopic binary in the Taurus star-forming region (SFR). We obtained new high angular resolution astrometry and high spectral resolution spectroscopy at Keck Observatory. The new data lead to a significant revision of previously published orbital parameters. In particular, we find that the masses of the primary and secondary are 0.86 ± 0.11 and 0.55 ± 0.05 M ☉, respectively, smaller than previously reported, and that the system lies 158.7 ± 3.9 pc from the sun, further than previously reported.
Limitation principles for mixed finite elements based on the Hu-Washizu variational formulation

Abstract In a pioneering paper Fraeijs de Veubeke introduced a limitation principle for finite elements based on the Hellinger-Reissner (two-field) variational formulation. In this paper, a similar principle is presented in the context of the Hu-Washizu (three-field) variational formulation.
Shape matching of partially occluded objects for image retrieval using hierarchical content description

This paper proposes a new contour based shape matching approach capable of recognizing partially occluded objects in images. There are tow major steps in the recognition process of partially occluded objects: 1) feature extraction, and 2) similarity matching. The features for a candidate image region are the contour for better accuracy in curvature estimation. To determine the similarity between a candidate region and an object template, we compute the Hausdorff distance from the contour of the candidate image region to that of the template, where the region contour has been mapped into the template domain. Once a match is established, the information is retained using a hierarchical content description scheme, enabling expedient object based image retrieval at a later time.
Stellar Abundances and Molecular Hydrogen in High-Redshift Galaxies: The Far-Ultraviolet View*

FUSE spectra of star-forming regions in nearby galaxies are compared to composite spectra of Lyman break galaxies (LBGs), binned by strength of Lyα emission and by mid-UV luminosity. Several far-UV spectral features, including lines dominated by stellar wind and by photospheric components, are very sensitive to stellar abundances. Their measurement in LBGs is compromised by the strong interstellar absorption features, allowing in some cases only upper limits to be determined. The derived C and N abundances in the LBGs are no higher than half solar (scaled to oxygen abundance for comparison with emission-line analyses), independent of the strength of Lyα emission. P V absorption indicates abundances as low as 0.1 solar, with an upper limit near 0.4 solar in the reddest and weakest emission galaxies. Unresolved interstellar absorption components would further lower the derived abundances. Trends of line strength and derived abundances are stronger with mid-UV luminosity than with Lyα strength. H2 absorption in the Lyman and Werner bands is very weak in the LBGs. Template H2 absorption spectra convolved to the appropriate resolution show that strict upper limits N(H2) < 1018 cm-2 apply in all cases, with more stringent values appropriate for the stronger emission composites and for mixes of H2 level populations like those on Milky Way sight lines. Since the UV-bright regions are likely to be widespread in these galaxies, these results rule out massive diffuse reservoirs of primordial H2 and suggest that the dust-to-gas ratio is already fairly large at z ≈ 3.
SETTING THE STAGE FOR CIRCUMSTELLAR INTERACTION IN CORE-COLLAPSE SUPERNOVAE. II. WAVE-DRIVEN MASS LOSS IN SUPERNOVA PROGENITORS

Supernovae (SNe) powered by interaction with circumstellar material provide evidence for intense stellar mass loss during the final years before core collapse. We have argued that during and after core neon burning, internal gravity waves excited by core convection can tap into the core fusion power and transport a super-Eddington energy flux out to the stellar envelope, potentially unbinding ~1 solar mass of material. In this work, we explore the internal conditions of SN progenitors using the MESA one-dimensional stellar evolution code in search of those most susceptible to wave-driven mass loss. We focus on simple, order of magnitude considerations applicable to a wide range of progenitors. Wave-driven mass loss during core neon and oxygen fusion happens preferentially in either lower mass (~20 solar mass zero-age main sequence) stars or massive, sub-solar metallicity stars. Roughly 20% of the SN progenitors we survey can excite 1046-48 erg of energy in waves that can potentially drive mass loss within a few months to a decade of core collapse. This energy can generate circumstellar environments with 10?3-1 solar masses reaching 100?AU before explosion. We predict a correlation between the energy associated with pre-SN mass ejection and the time to core collapse, with the most intense mass loss preferentially occurring closer to core collapse. During silicon burning, wave energy may inflate 10?3-1 solar masses of the envelope to 10-100?s of solar radii. This suggests that some nominally compact SN progenitors (Type Ibc progenitors) will have a significantly different SN shock breakout signature than traditionally assumed.
Prenatal Exposure to Curcumin Protects Rod Photoreceptors in a Transgenic Pro23His Swine Model of Retinitis Pigmentosa

PURPOSE Rhodopsin localization and rod photoreceptor (PR) morphology is altered in embryonic transgenic (Tg) Pro23His (P23H) miniswine. At birth, the Tg P23H swine retina lacks rod driven signaling. Curcumin, a neuroprotective food additive, has been shown to rescue Tg P23H rat rod PRs and promote normal trafficking of rhodopsin. We tested the hypothesis that prenatal exposure to curcumin would prevent PR morphological changes in Tg P23H miniswine retinae. METHODS A domestic sow was inseminated with semen from a Tg P23H miniswine founder. Her daily diet was supplemented with curcumin (100 mg/Kg body weight) from embryonic (E) day 80 to E112. The same diet without curcumin was fed to a second inseminated control sow. At E112, 2 days before parturition, both sows were euthanized. Their embryos were harvested, genotyped, and their eyes enucleated and prepared for morphological evaluation. RESULTS In all pigs, we measured mean outer retinal thickness, localization of rhodopsin, and rod PR morphology. Curcumin-treated Tg P23H swine embryonic retinas were similar to WT. Untreated Tg P23H embryonic retinas show significant degenerative effects; their outer retina was thinner, rod PR morphology was abnormal, and rhodopsin was mislocalized to the outer nuclear layer (ONL). CONCLUSIONS These data support a role for curcumin as a neuroprotective agent that prevents/delays morphological abnormalities associated with rod PR degeneration in this Tg P23H swine model of retinitis pigmentosa (RP). TRANSLATIONAL RELEVANCE Curcumin, a Food and Drug Administration-approved dietary supplement, may arrest/delay PR degeneration if ingested by individuals at risk for developing RP.
A Palladium-Catalyzed Glycosylation Reaction: The de Novo Synthesis of Natural and Unnatural Glycosides

A highly stereoselective and sterospecific palladium-catalyzed glycosylation reaction of a variety of alcohols is reported. The reaction selectively converts α-2-substituted 6-carboxy-2H-pyran-3(6H)-ones into α-2-substituted 6-alkoxy-2H-pyran-3(6H)-ones with complete retention of configuration and similarly converts the pyranones with β-carboxy groups into pyranones with β-alkoxy groups. The reaction works equally well with both amino acid- and carbohydrate-based alcohols. To demonstrate the utility of this process for carbohydrate chemistry several of the products were selectively converted into α-manno-pyranosides in two additional steps. Because the 2-substituted 6-carboxy-2H-pyran-3(6H)-ones are prepared by asymmetric synthesis, this reaction can be used for the preparation of either d- or l-pyranones.
Securing interdependent assets

Stackelberg security game models have become among the leading practical game theoretic approaches to security, having seen actual deployment in the LAX Airport, the United States Federal Air Marshals Service, and the United States Coast Guard, among others. However, most techniques for computing optimal security policies in Stackelberg games to date do not explicitly account for interdependencies among targets. We introduce a novel framework for computing optimal randomized security policies in networked (interdependent) domains. Our framework rests upon a Stackelberg security game model, within which we explicitly capture the indirect spread of damages due either to malicious attacks or unintended failures. We proceed to specify a particular simple, yet natural model of damage spread based on a graphical representation of asset interdependencies coupled with an independent failure cascade model. For the general model, we present an algorithm based on submodularity of the attacker's decision problem, in combination with local search, to approximate optimal security resource allocation across the assets, and show experimentally that our algorithm is far more scalable than an alternative exact approach, yields nearly optimal results, and offers substantial improvement over a well-known heuristic alternative. We then show that in a particular important special case we can compute optimal security policies exactly and efficiently. We proceed to apply our framework to study comparative network resilience, unifying previously disparate strands of research in the area, and to offer insights into other aspects of the interdependent security problem.
Evaluation of molecular models for the affinity maturation of antibodies: roles of cytosine deamination by AID and DNA repair.

One of the most complex and dispersed organs in the human body is the immune system which functions to identify and destroy invading infectious agents such as bacteria and viruses. It includes cells of discrete organs such as the spleen and thymus, but also components of other organs including bones (bone marrow) and the intestine (Peyer’s patch). Additionally, it uses a network of blood and lymphatic vessels that circulate molecules and cells through much of the body. When an infection threatens the body, various cells and molecules of the immune system work together to destroy the infectious particles. This represents a formidable defensive wall in healthy individuals against foreign invaders and is rarely breached. Of interest here are a series of programmed DNA alterations initiated by an enzyme, activation-induced deaminase (AID), that are essential for an effective immune response. The molecular mechanism of AID action and the response of the cell in the form of DNA repair will be discussed in detail below. A useful way to look at the immune system is to divide the immune response to an infection into two parts- the cellular response and the humoral response. The first of these refers to the action of cells like the killer T cells and involves direct interactions of these cells with other cells of the immune system and infected cells in the body. The other part, the humoral response, acts instead through antibodies. These proteins can have such a variety of structures that they bind an apparently limitless number of different small molecules such as fragments of proteins and lipopolysaccharides (collectively called antigens) derived from infectious agents. Antibodies are made by B lymphocytes (B cells) and form tight specific complexes with the antigens. This recognition of foreign antigens by antibodies helps other molecules and cells of the immune system to kill and destroy the infectious organism. The two types of immune responses are not completely separate and in fact work together. In particular, T cells play a crucial role in activating B cells to undergo genetic rearrangements described below. We will focus only on the humoral response in this review and cover the progress made in the field since 1999. However, we shall first describe some aspects of the immune response relevant to these alterations in an outline form and the reader is referred to a standard immunology textbook (See Ref. 1; for example) for additional details.
The diversity-multiplexing tradeoff of the symmetric MIMO 2-user interference channel

The fundamental diversity-multiplexing tradeoff (DMT) of the quasi-static fading, symmetric 2-user MIMO interference channel (IC) with channel state information at the transmitters (CSIT) and a short term average power constraint is obtained. The general case is considered where the interference-to-noise ratio (INR) at each receiver scales differently from the signal-to-noise ratio (SNR) at the receivers. The achievability of the DMT is proved by showing that a simple Han-Kobayashi coding scheme can achieve a rate region which is within a constant (independent of SNR) number of bits from a set of upper bounds to the capacity region of the IC. In general, only part of the DMT curve with CSIT can be achieved by coding schemes which do not use any CSIT (No-CSIT). A result in this paper establishes a threshold for the INR beyond which the DMT with CSIT coincides with that with No-CSIT. Our result also settles one of the conjectures made in [1]. Furthermore, the fundamental DMT of a class of non-symmetric ICs with No-CSIT is also obtained wherein the two receivers have different numbers of antennas.
On the Origin of Dynamically Cold Rings around the Milky Way

We present a scenario for the production of dynamically cold rings around the Milky Way via a high-eccentricity, flyby encounter. These initial conditions are more cosmologically motivated than those considered in previous works. We find that the encounters we examine generically produce a series of nearly dynamically cold ringlike features on low-eccentricity orbits that persist over timescales of ~2-4 Gyr via the tidal response of the primary galaxy to the close passage of the satellite. Moreover, they are both qualitatively and quantitatively similar to the distribution, kinematics, and stellar population of the Monoceros Ring. Therefore, we find that a high-eccentricity flyby by a satellite galaxy represents a cosmologically appealing scenario for forming kinematically distinct ringlike features around the Milky Way.
Path integrals and voronin's theorem on the universality of the riemann zeta function

We explore a new approach to the path integral for a latticized quantum theory. This talk is based on work with N. Khuri and H. Ren.
How Do Cohabiting Couples with Children Spend Their Money

Cohabitation is an increasingly prevalent living arrangement in the United States. Although the effects of living in a cohabiting arrangement on child well-being are not fully understood, the literature on children growing up in cohabiting families suggests that they have poorer developmental outcomes than do those growing up in married-parent families or in single-parent families. We use the Consumer Expenditure Survey to see if cohabiting couples with children spend their income on a different set of goods (i.e., have a different distribution of expenditure) than either married parents or single parents. Using a variety of analytical methods, we find that cohabiting couples spend a substantially larger share of their total expenditure on alcohol and tobacco than do either married-parent families or single parents. Cohabiting couples with children also spend less on health care and less on education than do married parents.
Exponential Gelfond–Khovanskii formula in dimension one

Gelfond and Khovanskii found a formula for the sum of the values of a Laurent polynomial over the zeros of a system of n Laurent polynomials in (C \ 0)". We expect that a similar formula holds in the case of exponential sums with real frequencies. Here we prove such a formula in dimension one.
On the Lattice Smoothing Parameter Problem

The smoothing parameter ηe(L) of a Euclidean lattice L, introduced by Micciancio and Regev (FOCS'04; SICOMP'07), is (informally) the smallest amount of Gaussian noise that “smooths out” the discrete structure of L (up to error e). It plays a central role in the best known worst-case/average-case reductions for lattice problems, a wealth of lattice-based cryptographic constructions, and (implicitly) the tightest known transference theorems for fundamental lattice quantities. In this work we initiate a study of the complexity of approximating the smoothing parameter to within a factor γ, denoted γ-GapSPP. We show that (for e = 1/ poly(n)): . (2+o(1))-GapSPP ∈ AM, via a Gaussian analogue of the classic Goldreich-Goldwasser protocol (STOC'98); . (1 + o(1))-GapSPP ∈ coAM, via a careful application of the Goldwasser-Sipser (STOC'86) set size lower bound protocol to thin shells in Rn; . (2 + o(1))-GapSPP E SZK ⊆ AM ∩ coAM (where SZK is the class of problems having statistical zero-knowledge proofs), by constructing a suitable instance-dependent commitment scheme (for a slightly worse o(1)-term); . (1 + o(1))-GapSPP can be solved in deterministic 2O(n) polylog(1/e) time and 2O(n) space. As an application, we demonstrate a tighter worst-case to average-case reduction for basing cryptography on the worstcase hardness of the GapSPP problem, with O(√n) smaller approximation factor than the GapSVP problem. Central to our results are two novel, and nearly tight, characterizations of the magnitude of discrete Gaussian sums over L: the first relates these directly to the Gaussian measure of the Voronoi cell of L, and the second to the fraction of overlap between Euclidean balls centered around points of L.