cssi/SciSciGPT-SciSciNet huggingface dataset:
Analysis and Enumeration of Absorbing Sets for Non-Binary Graph-Based Codes

In this work, we first provide the definition of absorbing sets for linear channel codes over non-binary alphabets. In a graphical representation of a non-binary channel code, an absorbing set can be described by a collection of topological and edge labeling conditions. In the non-binary case, the equations relating neighboring variable and check nodes are over a non-binary field, and the edge weights are given by the non-zero elements of that non-binary field. As a consequence, it becomes more difficult for a given structure to satisfy the absorbing set constraints compared to the binary case. This observation in part explains the superior performance of non-binary codes over their binary counterparts. We show that the conditions in the non-binary absorbing set definition can be simplified in the case of non-binary elementary absorbing sets. Based on these simplified conditions, we provide design guidelines for finite-length non-binary codes free of small non-binary elementary absorbing sets. These guidelines demonstrate that even under the preserved topology, the performance of a non-binary graph-based code in the error floor region can be substantially improved by manipulating edge weights so as to avoid small absorbing sets. Our various simulation results suggest that the proposed non-binary absorbing set definition is useful for a range of code constructions and decoders. Finally, by using both insights from graph theory and combinatorial techniques, we establish the asymptotic distribution of non-binary elementary absorbing sets for regular code ensembles.
Pd(II)-Catalyzed C–H Functionalizations Directed by Distal Weakly Coordinating Functional Groups

Ortho-C(sp2)–H olefination and acetoxylation of broadly useful synthetic building blocks phenylacetyl Weinreb amides, esters, and ketones are developed without installing an additional directing group. The interplay between the distal weak coordination and the ligand-acceleration is crucial for these reactions to proceed under mild conditions. The tolerance of longer distance between the target C–H bonds and the directing functional groups also allows for the functionalizations of more distal C–H bonds in hydrocinnamoyl ketones, Weinreb amides, and biphenyl Weinreb amides. Mechanistically, the coordination of these carbonyl groups and the bisdentate amino acid ligand with Pd(II) centers provides further evidence for our early hypothesis that the carbonyl groups of the potassium carboxylate are responsible for the directed C–H activation of carboxylic acids.
The emission thermophotometry (ETP) of some amino acids

Abstract The emission thermophotometry (ETP) curves of ten selected amino acids were determined in a flowing oxygen atmosphere. Most of the ETP curves contained a single emission peak in the 230–350°C temperature range; several of the curves contained multiple peaks and/or shoulder peaks. The light emission varied in intensity for each amino acid, but in most cases was at a very low level. The origin of the light emission process is not known but it is probably due to the presence of unstable pyrolysis products.
The Radio and X-Ray-Luminous Type Ibc Supernova 2003L

We present extensive radio observations of SN 2003L, the most luminous and energetic Type Ibc radio supernova with the exception of SN 1998bw (associated with GRB 980425). Observations from the Very Large Array are well described by fitting a synchrotron self-absorption model to the emission spectrum. This model implies a subrelativistic ejecta velocity, ≈ 0.2c, and a size of r ≈ 4.3 × 1015 cm at t ≈ 10 days. The circumstellar density is suitably fitted with a stellar wind profile, ne ∝ r-2 cm-3 and a constant mass-loss rate of ≈ 7.5 × 10-6 M☉ yr-1. Moreover, the magnetic field follows B ∝ r-1 and the kinetic energy of the radio-bright ejecta is roughly E ≈ 1048 ergs assuming equipartition of energy between relativistic electrons and magnetic fields. Furthermore, we show that free-free absorption does not contribute significantly to the radio spectrum, since it implies ejecta velocities that are inconsistent with size constraints derived from Very Long Baseline Array observations. In conclusion, we find that although SN 2003L has a radio luminosity comparable to that seen in SN 1998bw, it shows no evidence for a significant amount of energy coupled to relativistic ejecta. Using SN 2003L as an example, we comment briefly on the coupling of ejecta velocity and energy in Type Ibc supernovae.
WILL COMET ISON (C/2012 S1) SURVIVE PERIHELION?

On 2013 November 28 Comet ISON (C/2012 S1) will pass by the Sun with a perihelion distance of 2.7 solar radii. Understanding the possible outcomes for the comet's response to such a close passage by the Sun is important for planning observational campaigns and for inferring ISON's physical properties. We present new numerical simulations and interpret them in context with the historical track record of comet disruptions and of sungrazing comet behavior. Historical data suggest that sizes below ~200?m are susceptible to destruction by sublimation driven mass loss, while we find that for ISON's perihelion distance, densities lower than 0.1?g?cm?3 are required to tidally disrupt a retrograde or non-spinning body. Such low densities are substantially below the range of the best-determined comet nucleus densities, though dynamically new comets such as ISON have few measurements of physical properties. Disruption may occur for prograde rotation at densities up to 0.7?g?cm?3, with the chances of disruption increasing for lower density, faster prograde rotation, and increasing elongation of the nucleus. Given current constraints on ISON's nucleus properties and the typically determined values for these properties among all comets, we find tidal disruption to be unlikely unless other factors (e.g., spin-up via torquing) affect ISON substantially. Whether or not disruption occurs, the largest remnant must be big enough to survive subsequent mass loss due to sublimation in order for ISON to remain a viable comet well after perihelion.
Fusion neutron irradiation of Ni-Si alloys at high temperature☆

Abstract Two Ni-4% Si alloys, with different cold work levels, have been irradiated with 14-MeV fusion neutrons at 623 K, and their Curie temperatures have been monitored during irradiation. The results are compared to those of an identical alloy irradiated by 2-MeV electrons. The results show that increasing dislocation density increases the Curie temperature change rate. At the same damage rate, the Curie temperature change rate for the alloy irradiated by 14-MeV fusion neutrons is only 6–7% of that for an identical alloy irradiated by 2-MeV electrons. It is well known that the migration of radiation induced defects contributes to segregation of silicon atoms at sinks in this alloy, causing the Curie temperature changes. The current results imply that the relative free defect production efficiency decreases from one for the electron irradiated sample to 6–7% for the fusion neutron irradiated sample.
Early Mars: How warm and how wet?

It is clear that conditions on Mars during the Noachian period, which extended from the beginning of Mars' geologic record to something like 3.9 b.y.a., were significantly different than they are today. As on the other planets, the meteoritic bombardment rate was far higher than it is at present, as evidenced by the densely cratered nature of Noachian terrains. But there were other differences as well, some inferred, some more obvious. The nature of these differences and what they imply about broader topics of planetary evolution were the primary subjects of the workshop, “Early Mars: How Warm and How Wet?,” held July 26–28, in Breckenridge, Colo. The workshop was sponsored by NASA's Mars' Surface and Atmosphere Through Time (MSATT) program.
PRODUCTION OF TWO OVERLAPPING BOSE-EINSTEIN CONDENSATES BY SYMPATHETIC COOLING

A new apparatus featuring a double magneto-optic trap and an Ioffe-type magnetic trap was used to create condensates of $2\ifmmode\times\else\texttimes\fi{}{10}^{6}$ atoms in either of the $|F\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2,m\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2〉$ or $|F\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1,m\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{-}1〉$ spin states of ${}^{87}$Rb. Overlapping condensates of the two states were also created using nearly lossless sympathetic cooling of one state via thermal contact with the other evaporatively cooled state. We observed that (i) the scattering length of the $|1,\ensuremath{-}1〉$ state is positive, (ii) the rate constant for binary inelastic collisions between the two states is $2.2(9)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}14}{\mathrm{cm}}^{3}/\mathrm{s}$, and (iii) there is a repulsive interaction between the two condensates. Similarities and differences between the behaviors of the two spin states are observed.
Special determinants in higher-rank Brill-Noether theory

Extending our previous study of modified expected dimensions for rank-2 Brill–Noether loci with prescribed special determinants, we introduce a general framework which applies a priori for arbitrary rank, and use it to prove modified expected dimension bounds in several new cases, applying both to rank 2 and to higher rank. The main tool is the introduction of generalized alternating Grassmannians, which are the loci inside Grassmannians corresponding to subspaces which are simultaneously isotropic for a family of multilinear alternating forms on the ambient vector space. In the case of rank 2 with two-dimensional spaces of sections, we adapt arguments due to Teixidor i Bigas to show that our new modified expected dimensions are in fact sharp.
Kalman Filter Modification in Adaptive Control

This paper presents a novel Kalman-filter-based approach for approximately enforcing a linear constraint in adaptive control. One application is that this leads to alternative forms for well-known modification terms such as e modification. It is shown that employing this approach does not increase the theoretical guaranteed ultimate bounds for the closed-loop error signals of an existing adaptive design. In addition, it leads to smaller tracking errors without incurring significant oscillations in the system response and without requiring high modification gain. Three novel modifications to classical adaptive laws are illustrated and tested on a model of wing rock dynamics.
Environmental Control of Cloud-to-Ground Lightning Polarity in Severe Storms

Abstract In this study, it is hypothesized that the mesoscale environment can indirectly control the cloud-to-ground (CG) lightning polarity of severe storms by directly affecting their structural, dynamical, and microphysical properties, which in turn directly control cloud electrification and ground flash polarity. A more specific hypothesis, which has been supported by past observational and laboratory charging studies, suggests that broad, strong updrafts and associated large liquid water contents in severe storms lead to the generation of an inverted charge structure and enhanced +CG lightning production. The corollary is that environmental conditions favoring these kinematic and microphysical characteristics should support severe storms generating an anomalously high (>25%) percentage of +CG lightning (i.e., positive storms) while environmental conditions relatively less favorable should sustain storms characterized by a typical (≤25%) percentage of +CG lightning (i.e., negative storms). Forty-eight...
The sorting order on a Coxeter group

Let (W,S) be an arbitrary Coxeter system. For each word @w in the generators we define a partial order-called the @w-sorting order-on the set of group elements W"@w@?W that occur as subwords of @w. We show that the @w-sorting order is a supersolvable join-distributive lattice and that it is strictly between the weak and Bruhat orders on the group. Moreover, the @w-sorting order is a ''maximal lattice'' in the sense that the addition of any collection of Bruhat covers results in a nonlattice. Along the way we define a class of structures called supersolvable antimatroids and we show that these are equivalent to the class of supersolvable join-distributive lattices.
Another Combinatorial Determinant

We present a variation and generalization of a determinant evaluation of Wilf (math.CO/9809120). His result concerns a matrix whose entries are the coefficients of powers of a given power series; we replace the powers by repeated compositions and obtain similar results.
THE ORIGIN OF THE VIRGO STELLAR SUBSTRUCTURE

We present three-dimensional space velocities of stars selected to be consistent with membership in the Virgo stellar substructure. Candidates were selected from SA 103, a single 40' Multiplication-Sign 40' field from our proper-motion (PM) survey in Kapteyn's Selected Areas (SAs), based on the PMs, Sloan Digital Sky Survey (SDSS) photometry, and follow-up spectroscopy of 215 stars. The signature of the Virgo substructure is clear in the SDSS color-magnitude diagram (CMD) centered on SA 103, and 16 stars are identified that have high Galactocentric-frame radial velocities (V{sub GSR} > 50 km s{sup -1}) and lie near the CMD locus of Virgo. The implied distance to the Virgo substructure from the candidates is 14 {+-} 3 kpc. We derive mean kinematics from these 16 stars, finding a radial velocity V{sub GSR} = 153 {+-} 22 km s{sup -1} and proper motions ({mu}{sub {alpha}}cos {delta}, {mu}{sub {delta}}) = (- 5.24, -0.91) {+-} (0.43, 0.46) mas yr{sup -1}. From the mean kinematics of these members, we determine that the Virgo progenitor was on an eccentric (e {approx} 0.8) orbit that recently passed near the Galactic center (pericentric distance R{sub p} {approx} 6 kpc). This destructive orbit is consistent with the idea that the substructure(s)more » in Virgo originated in the tidal disruption of a Milky Way satellite. N-body simulations suggest that the entire cloud-like Virgo substructure (encompassing the 'Virgo Overdensity' and the 'Virgo Stellar Stream') is likely the tidal debris remnant from a recently disrupted massive ({approx}10{sup 9} M{sub Sun }) dwarf galaxy. The model also suggests that some other known stellar overdensities in the Milky Way halo (e.g., the Pisces Overdensity and debris near NGC 2419 and SEGUE 1) are explained by the disruption of the Virgo progenitor.« less
Modular invariance, self-duality and the phase transition between quantum Hall plateaus

We investigate the problem of the superuniversality of the phase transition between different quantum Hall plateaus. We construct a set of models which give a qualitative description of this transition in a pure system of interacting charged particles. One of the models is manifestly invariant under both duality and periodic shifts of the statistical angle and, hence, it has a full modular invariance. We derive the transformation laws for the correlation functions under the modular group and use them to derive symmetry constraints for the conductances. These allow us to calculate exactly the conductivities at the modular fixed points. We show that, at least at the modular fixed points, the system is critical. Away from the fixed points, the behavior of the model is determined by extra symmetries such as time reversal. We speculate that if the natural connection between spin and statistics holds, the model may exhibit an effective analyticity at low energies. In this case, the conductance is completely determined by its behavior under modular transformations.
Direct and indirect effects of anthropogenic aerosols on regional precipitation over east Asia

[1] A regional coupled climate-chemistry-aerosol model is developed. It is used to assess the direct and indirect effects of anthropogenic sulfate and carbonaceous aerosols on regional climate over east Asia with a focus on precipitation. The simulated direct and first indirect effects for the most part reduce the solar radiation and hence decrease the surface temperature, while the second indirect effect generates both negative solar forcing and a substantial positive long-wave forcing. It decreases the precipitation, but because of the cancelling effect, surface temperature does not change very much. With the interactively model-calculated current aerosol loading and the combined direct/semidirect/first indirect effect, the simulated precipitation is reduced by about 10% in the fall and winter and by about 5% in the spring and summer. The second indirect effect has the largest impact, by itself decreasing the fall and winter precipitation from about 3% to 20%, depending on the autoconversion scheme assumed. The semidirect effect on precipitation is relatively small. An empirical orthogonal function analysis of climatological precipitation over east Asia since the last century shows a decreasing trend of the leading modes over most of China in the fall and winter, which is generally geographically consistent with the distribution of the model-simulated precipitation reduction from anthropogenic aerosols.
Improved Methods for Sampling Gas and Drill Cuttings

Etude de deux concepts-cles de l'analyse des mud logs. Neuf types differents de separateurs de gaz ont ete testes selon les conditions operatoires conseillees par les fournisseurs. Les reponses varient de deux ordres de grandeur, et beaucoup de separateurs n'exhibent pas une reponse lineaire aux changements de teneur en methane des boues. La presence d'un rebord de fond et l'introduction de bulles dans le separateur par une lame agitatrice, ameliorent les performances du dispositif. Dans une deuxieme partie, un equipement est decrit qui permet d'obtenir des cuttings avant leur passage dans le crible a secousses, eliminant ainsi le risque d'erreurs humaines et augmentant le taux de recuperation des fines, d'ou une representativite accrue
FS 3 : A sampling based method for top-k frequent subgraph mining

Mining labeled subgraph is a popular research task in data mining because of its potential application in many different scientific domains. All the existing methods for this task explicitly or implicitly solve the subgraph isomorphism task which is computationally expensive, so they suffer from the lack of scalability problem when the graphs in the input database are large. In this work, we propose FS3, which is a sampling based method. It mines a small collection of subgraphs that are most frequent in the probabilistic sense. FS3 performs a Markov Chain Monte Carlo (MCMC) sampling over the space of a fixed-size subgraphs such that the potentially frequent subgraphs are sampled more often. Besides, FS3 is equipped with an innovative queue manager. It stores the sampled subgraph in a finite queue over the course of mining in such a manner that the top-k positions in the queue contain the most frequent subgraphs. Our experiments on database of large graphs show that FS3 is efficient, and it obtains subgraphs that are the most frequent amongst the subgraphs of a given size.
27Al NMR, FT-IR and Ethanol-18O TPD Characterization of Fluorided Alumina

A series of F/Al2O3 samples (wt% F = 0 to 20) has been studied using a combination of solid-state 27Al NMR, FT-IR, and ethanol-18O TPD techniques. Solid-state 27Al NMR is particularly sensitive to amorphous phases or small crystallites present on the catalyst surface, many of which cannot be detected by XRD. 27Al NMR shows the presence of three types of AlF3(H2O)n species (with n varying between 0 and 3) on fluorided alumina. FT-IR studies of ethanol adsorption show that fluoride blocks the sites required for dissociative chemisorption of ethanol. A similar analysis of adsorbed pyridine shows an increase in the number of Bronsted acid sites with the addition of up to 10 wt% fluoride. However, increasing the fluoride loading to 20 wt% decreases the number of Bronsted acid sites. The TPD of ethanol-18O from F/Al2O3 samples shows that at low levels fluoride serves to block Lewis acid sites, but at higher levels its predominant role is to increase the Bronsted acidity of the alumina surface. The pyridine adsorption and TPD experiments show that fluoride strengthens the remaining Lewis acid sites.
The potential impact of palivizumab on pediatric airway reconstruction

Abstract Purpose To examine the role of palivizumab, a monoclonal antibody vaccine designed to prevent respiratory syncytial virus (RSV) infection, in the surgical setting, and to explore the feasibility, in terms of medical benefit and cost, of its use in pediatric airway reconstruction patients. Materials and methods Literature review of MEDLINE database using the following indexing terms (“respiratory syncytial virus,” “palivizumab,” “laryngotracheal reconstruction,” and “cricotracheal reconstruction”) and limited to following subcategories (English language, postoperative complication, and morbidity and mortality). All phase IV clinical trials reporting data regarding safety, efficacy, and application of palivizumab in the general pediatric population were selected, as well as all studies from any surgical specialty with data on postoperative outcome complicated by RSV infection. Results The literature demonstrates significant postoperative morbidity and mortality attributable to RSV infection within several surgical specialties including otolaryngology. Meta-analysis of the data from phase IV clinical trials suggests potential benefit from the perioperative use of palivizumab. The cost of vaccination is the principal limiting factor preventing its more widespread application. Conclusion Otolaryngologists need to be aware of the potential significant morbidity caused by perioperative RSV infection and should consider the prophylactic use of palivizumab in their pediatric airway reconstruction patients in high-risk seasons. A large multicenter study would be required to adequately perform a cost-benefit analysis of palivizumab use for this specific indication.
Smoothed Particle Hydrodynamics Simulations of Apsidal and Nodal Superhumps.

In recent years, a handful of systems have been observed to show "negative" (nodal) superhumps, with periods slightly shorter than the orbital period. It has been suggested that these modes are a consequence of the slow retrograde precession of the line of nodes in a disk tilted with respect to the orbital plane. Our simulations confirm and refine this model: they suggest a roughly axisymmetric, retrogradely precessing, tilted disk that is driven at a period slightly less than half the orbital period as the tidal field of the orbiting secondary encounters, in turn, the two halves of the disk above and below the midplane. Each of these passings leads to viscous dissipation on one face of an optically thick disk—observers on opposite sides of the disk would each observe one brightening per orbit, but 180° out of phase with each other.
Chemoenzymatic approaches to glycoprotein synthesis

The construction of homogeneous glycoproteins presents a formidable challenge to the synthetic chemist. Over the past few years there has been an explosion in the number of methods developed to address this problem. These methods include the development of novel ligation technologies for the synthesis of the protein backbone, as well chemical and enzymatic approaches for introducing complex glycans into the peptide backbone. This tutorial review discusses the application of these techniques to the synthesis of peptides and proteins possessing well defined glycans.
Truss assembly and welding by Intelligent Precision Jigging Robots

This paper describes an Intelligent Precision Jigging Robot (IPJR) prototype that enables the precise alignment and welding of titanium space telescope optical benches. The IPJR, equipped with micron accuracy sensors and actuators, worked in tandem with a lower precision remote controlled manipulator. The combined system assembled and welded a 2 m truss from stock titanium components. The calibration of the IPJR, and the difference between the predicted and the truss dimensions as-built, identified additional sources of error that should be addressed in the next generation of IPJRs in 2D and 3D.
Experimental investigation of undesired stable equilibria in pumpkin shape super-pressure balloon designs

Abstract Excess in skin material of a pneumatic envelope beyond what is required for minimum enclosure of a gas bubble is a necessary but by no means sufficient condition for the existence of multiple equilibrium configurations for that pneumatic envelope. The very design of structurally efficient super-pressure balloons of the pumpkin shape type requires such excess. Undesired stable equilibria in pumpkin shape balloons have been observed on experimental pumpkin shape balloons. These configurations contain regions with stress levels far higher than those predicted for the cyclically symmetric design configuration under maximum pressurization. Successful designs of pumpkin shape super-pressure balloons do not allow such undesired stable equilibria under full pressurization. This work documents efforts made so far and describes efforts still underway by the National Aeronautics and Space Administration’s Balloon Program Office to arrive on guidance on the design of pumpkin shape super-pressure balloons that guarantee full and proper deployment.
Analysis of a strain softening constitutive model

Abstract The paper first examines the question of uniqueness of a basic yet simplified constitutive model with strain softening. It is shown that the constitutive equations lead to a unique solution for the case of rate-dependent as well as rate-independent formulation and its implementation in finite element analysis shows mesh size insensitivity in the hardening and softening regimes. Conditions for formation of narrow shear bands are developed and discussed. It is shown that as the damage accumulates the material approaches localization of deformation.
Understanding soft errors in uncore components

The effects of soft errors in processor cores have been widely studied. However, little has been published about soft errors in uncore components, such as memory subsystem and I/O controllers, of a System-on-a-Chip (SoC). In this work, we study how soft errors in uncore components affect system-level behaviors. We have created a new mixed-mode simulation platform that combines simulators at two different levels of abstraction, and achieves 20,000× speedup over RTL-only simulation. Using this platform, we present the first study of the system-level impact of soft errors inside various uncore components of a large-scale, multi-core SoC using the industrial-grade, open-source OpenSPARC T2 SoC design. Our results show that soft errors in uncore components can significantly impact system-level reliability. We also demonstrate that uncore soft errors can create major challenges for traditional system-level checkpoint recovery techniques. To overcome such recovery challenges, we present a new replay recovery technique for uncore components belonging to the memory subsystem. For the L2 cache controller and the DRAM controller components of OpenSPARC T2, our new technique reduces the probability that an application run fails to produce correct results due to soft errors by more than 100× with 3.32% and 6.09% chip-level area and power impact, respectively.
A new model of the hydrogen and helium-broadened microwave opacity of ammonia based on extensive laboratory measurements

Abstract Close to 2000 laboratory measurements of the microwave opacity and refractivity of gaseous NH 3 in an H 2 /He atmosphere have been conducted in the 1.1–20 cm wavelength range (1.5–27 GHz) at pressures from 30 mbar to 12 bar and at temperatures from 184 to 450 K. The mole fraction of NH 3 ranged from 0.06 to 6% with some additional measurements of pure NH 3 . The high accuracy of these results have enabled development of a new model for the opacity of NH 3 in a H 2 /He atmosphere under jovian conditions. The model employs the Ben-Reuven lineshape applied to the published inversion line center frequencies and intensities of NH 3 (JPL Catalog—[Pickett, H.M., Poynter, R.L., Cohen, E.A., Delitsky, M.L., Pearson, J.C., Muller, H.S.P., 1998. J. Quant. Spectrosc. Radiat. Trans. 60, 883–890]) with empirically-fitted line parameters for H 2 and He broadening, and for the self-broadening of some previously unmeasured ammonia inversion lines. The new model for ammonia opacity will provide reliable results for temperatures from 150 to 500 K, at pressures up to 50 bar and at frequencies up to 40 GHz. These results directly impact the retrieval of jovian atmospheric constituent abundances from the Galileo Probe radio signal absorption measurements, from microwave emission measurements conducted with Earth-based radio telescopes and with the future NASA Juno mission, and studies of Saturn's atmosphere conducted with the Cassini Radio Science Experiment and the Cassini RADAR 2.1 cm passive radiometer.
Relationship between obesity, diabetes and the risk of thyroid cancer ☆,☆☆

Abstract Purpose Analyze the relationship between obesity and type-2 diabetes mellitus (DM) and the development of differentiated thyroid cancer (DTC). Materials and methods A randomized case-controlled retrospective chart review of outpatient clinic patients at an academic medical center between January 2005 and December 2012. DTC patients were compared to two control groups: primary hyperparathyroidism (PHPTH) patients with euthyroid state and Internal Medicine (IM) patients. Exposure variables included historical body-mass-index (BMI), most recent BMI within 6 months and DM. Multivariate logistic regressions adjusting for gender, age, and year of BMI assessed the adjusted Odds Ratio (OR) of DTC with both BMI and DM. Results Comparison of means showed a statistically significant higher BMI in DTC (BMI = 37.83) than PHPTH, IM, and pooled controls, BMI = 30.36 p = Conclusion Our results show that obesity and, to a lesser degree, DM are significantly associated with DTC. BMI in particular was a strong predictive variable for DTC (C = 0.82 bivariate, C = 0.84 multivariate).
A mechanistic investigation of gelation. The sol-gel polymerization of precursors to bridged polysilsesquioxanes.

The study of a homologous series of precursors to bridged polysilsesquioxanes has uncovered striking discontinuities in gelation behavior. An investigation of the chemistry during the early stages of the polymerization has provided a molecular basis for these observations. Monomers containing from one to four bridging carbon atoms exhibit a pronounced tendency to undergo rapid intra- or bimolecular cyclization. The cyclic and bicyclic intermediates have been characterized by 29Si NMR spectroscopy, chemical ionization mass spectrometry, and isolation from the reaction solution. These carbosiloxanes are local thermodynamic sinks that produce kinetic bottlenecks in the production of high-molecular-weight silsesquioxanes. The formation of cyclic carbosiloxanes results in slowing, or in some cases completely shutting down, gelation. An additional finding is that the cyclic structures are incorporated intact into the final xerogel.
LATTICE CONGRUENCES OF THE WEAK ORDER

We study the congruence lattice of the poset of regions of a hyperplane arrangement, with particular emphasis on the weak order on a finite Coxeter group. Our starting point is a theorem from a previous paper which gives a geometric description of the poset of join-irreducibles of the congruence lattice of the poset of regions in terms of certain polyhedral decompositions of the hyperplanes. For a finite Coxeter system (W, S) and a subset K ⊆ S ,l etηK : wwK be the projection onto the parabolic subgroup WK . We show that the fibers of ηK constitute the smallest lattice congruence with 1 ≡ s for every s ∈ (S − K). We give an algorithm for determining the congruence lattice of the weak order for any finite Coxeter group and for a finite Coxeter group of type A or B we define a directed graph on subsets or signed subsets such that the transitive closure of the directed graph is the poset of join-irreducibles of the congruence lattice of the weak order. Mathematics Subject Classifications (2000): Primary 20F55, 06B10; secondary 52C35.
Ray shooting and other applications of spanning trees with low stabbing number

@ of n (possibly intersecting) line segments in the plane, preprocess them so that, given a query ray r emanating from a point p, we can quickly compute the intersection point P(
Reserve Prices in Repeated Auctions

This paper aims to estimate the effect of imposing a reserve price in repeated auctions of homogeneous items. I model the behavior of impatient bidders who search for the best auction outcome over time. The model is used to develop estimating equations for the bidders’ valuations, and to evaluate the effect of reserve prices on bids and revenue. Using data collected from surplus auctions of personal computer processors, I find economically significant gains from imposing a reserve price. The revenue-maximizing reserve price improves revenue by about 23% for a large subsample of the auctions in the data.
A novel synthesis of 2,5-diaryl-3-(phenylmethyl)thiophenes

Abstract Addition of phenylmethanethiols (benzylthiols), including (2-furyl)methanethiol, to butadiynes in potassium hydroxide/dimethyl sulfoxide affords the corresponding 2,5-diaryl-3-(phenylmethyl)thiophenes.
Hydrogen: Primary or Supplementary Fuel for Automotive Engines

Abstract Hydrogen, gasoline, and mixtures thereof were compared as fuels for lean-burn engines. Hydrogen for the mixed fuels tests was generated by partial oxidation of gasoline. Hydrogen combustion yielded the highest thermal efficiency at any NO x level. Gasoline yielded the second highest thermal efficiency for NO x levels greater than or approximately equal to 2 g/mile. For lower NO levels and high vehicle inertia weights, progressively more hydrogen supplementation was the second most efficient system. For vehicle inertia weights below 5000 lbm (2300 kg), the statutory NO standard (0.4 g/mile) could be met with one lbm/h (0.13 g/s) hydrogen supplementation.
Electrochemical impedance spectroscopy study of the passive films of alloy 22 in low pH nitrate and chloride environments

Utilizing electrochemical impedance spectroscopy (EIS), we characterize the passive film properties of alloy 22 during immersion in low pH nitrate and chloride solutions. In pure HCl, the passive film grows thinner with increasing acid concentration. In contrast, in HNO3, the passive film corrosion protection properties are enhanced, which leads to low corrosion rates, even at pH < −0.5. The combined influence of both HCl and HNO3 in contact simultaneously with the alloy 22 surface shows multiple phases in the passive film properties depending on the pH. EIS results show that the passive film changes either thickness and/or composition as the system is driven chemically through different corrosion states, including: active, passive, active/passive and transpassive.
Do cyclic nucleotides promote the trans-synaptic induction of tyrosine hydroxylase?

Publisher Summary This chapter discusses the role of cyclic nucleotides in promoting the trans-synaptic induction of tyrosine hydroxylase. An increase of activity at synapses impinging on either sympathetic ganglia or adrenal chromaffin cells results in an induction of tyrosine hydroxylase. This induction is termed trans-synaptic and occurs after time latency from the termination of the stimulus. Such latency implicates intermediate steps in transforming the increase of synaptic activity into a change of protein synthesis. The chapter also discusses the molecular nature of the events that transform stimulation of synaptic receptors located in the membrane of post junctional cells into an intracellular effector stimulus that increases the number of molecules of the inducible TH. The studies have identified three phases in the sequence of intracellular events which cause the induction of TH in adrenal medulla and superior cervical ganglia of demedullated rats after cold exposure. The cAMP/cGMP concentration ratio increases as a result of the extraordinary high rate of transmitter release. This increase persists for about 90 min and during the subsequent 10 to 18 hours a series of biochemical events occur, including de novo synthesis of specific messenger RNA.
The virus of my virus is my friend: ecological effects of virophage with alternative modes of coinfection.

Virophages are viruses that rely on the replication machinery of other viruses to reproduce within eukaryotic hosts. Two different modes of coinfection have been posited based on experimental observation. In one mode, the virophage and the virus enter the host independently. In the other mode, the virophage adheres to the virus so both virophage and virus enter the host together. Here we ask: what are the ecological effects of these different modes of coinfection? In particular, what ecological effects are common to both infection modes, and what are the differences particular to each mode? We develop a pair of biophysically motivated ODE models of viral-host population dynamics, corresponding to dynamics arising from each mode of infection. We find that both modes of coinfection allow for the coexistence of the virophage, virus, and host either at a stable fixed point or through cyclical dynamics. In both models, virophage tends to be the most abundant population and their presence always reduces the viral abundance and increases the host abundance. However, we do find qualitative differences between models. For example, via extensive sampling of biologically relevant parameter space, we only observe bistability when the virophage and the virus enter the host together. We discuss how such differences may be leveraged to help identify modes of infection in natural environments from population level data.
The directional distance function and measurement of super-efficiency : an application to airlines data

In a recent paper published in this Journal, Lovell and Rouse (LR) proposed a modification of the standard data envelopment analysis (DEA) model that overcomes the infeasibility problem often encountered in computing super-efficiency. In the LR procedure one appropriately scales up the observed input vector (scale down the output vector) of the relevant super-efficient firm thereby usually creating its inefficient surrogate. By contrast, Chen suggested a different procedure that replaces input–output bundles that are found to be inefficient in standard DEA by their efficient projections. An alternative procedure proposed in this paper uses the directional distance function and the resulting Nerlove–Luenberger measure of super-efficiency. The fact that the directional distance function combines, by definition, features of both an input-oriented and an output-oriented model, generally leads to a complete ranking of the observations and is easily interpreted. A dataset on international airlines is utilized in an illustrative empirical application.
DYNAMICAL EVOLUTION OF PLANETESIMALS IN PROTOPLANETARY DISKS

The current picture of terrestrial planet formation relies heavily on our understanding of the dynamical evolution of planetesimals—asteroid-like bodies thought to be planetary building blocks. In this study we investigate the growth of eccentricities and inclinations of planetesimals in spatially homogeneous protoplanetary disks using methods of kinetic theory. Emphasis is put on clarifying the effect of gravitational scattering between planetesimals on the evolution of their random velocities. We explore disks with a realistic mass spectrum of planetesimals evolving in time, similar to that obtained in self-consistent simulations of planetesimal coagulation: the distribution scales as a power law of mass for small planetesimals and is supplemented by an extended tail of bodies at large masses representing the ongoing runaway growth in the system. We calculate the behavior of planetesimal random velocities as a function of the planetesimal mass spectrum both analytically and numerically; results obtained by the two approaches agree quite well. Scaling of random velocity with mass can always be represented as a combination of power laws corresponding to different velocity regimes (shear- or dispersion-dominated) of planetesimal gravitational interactions. For different mass spectra we calculate analytically the exponents and time-dependent normalizations of these power laws, as well as the positions of the transition regions between different regimes. It is shown that random energy equipartition between different planetesimals can only be achieved in disks with very steep mass distributions (the differential surface number density of planetesimals falling off steeper than m-4) or in the runaway tails. In systems with shallow mass spectra (shallower than m-3) the random velocities of small planetesimals turn out to be independent of their masses. We also discuss the damping effects of inelastic collisions between planetesimals and of gas drag, and their importance in modifying planetesimal random velocities.
Exact Bures probabilities that two quantum bits are classically correlated

In previous studies, we have explored the ansatz that the volume elements of the Bures metrics over quantum systems might serve as prior distributions, in analogy with the (classical) Bayesian role of the volume elements (“Jeffreys' priors”) of Fisher information metrics. Continuing this work, we obtain exact Bures prior probabilities that the members of certain low-dimensional subsets of the fifteen-dimensional convex set of density matrices are separable or classically correlated. The main analytical tools employed are symbolic integration and a formula of Dittmann (J. Phys. A 32, 2663 (1999)) for Bures metric tensors. This study complements an earlier one (J. Phys. A 32, 5261 (1999)) in which numerical (randomization) - but not integration - methods were used to estimate Bures separability probabilities for unrestricted and density matrices. The exact values adduced here for pairs of quantum bits (qubits), typically, well exceed the estimate ( ) there, but this disparity may be attributable to our focus on special low-dimensional subsets. Quite remarkably, for the q= 1 and states inferred using the principle of maximum nonadditive (Tsallis) entropy, the Bures probabilities of separability are both equal to . For the Werner qubit-qutrit and qutrit-qutrit states, the probabilities are vanishingly small, while in the qubit-qubit case it is .
The Effects of Low-Temperature Dielectronic Recombination on the Relative Populations of the Fe M-Shell States

We examine the effects of low-temperature, or Δn = 0, dielectronic recombination (DR) on the ionization balance of the Fe M shell (Fe IX-Fe XVI). Since Δn = 0 rates are not available for these ions, we have derived estimates based on the existing rates for the first four ionization states of the CNO sequence and newly calculated rates for L-shell ions of third-row elements and Fe. For a range of ionization parameter and column density applicable to the intrinsic absorbers detected in ASCA, Chandra, and XMM-Newton observations of Seyfert galaxies, we generated two grids of photoionization models, with and without DR. The results show that the ionization parameter at which the population of an Fe M-shell ion peaks can increase in some cases by a factor of more than 2 when these rates are included. More importantly, there are dramatic changes in the range in ionization parameter over which individual M-shell ions contain significant fractions of the total Fe (e.g., >10%) in the plasma. These results may explain the mismatch between the range of Fe ionization states detected in the X-ray spectra of Seyfert galaxies, identified by the energies of the M-shell unresolved transition array, and those predicted by photoionization models of the X-ray absorbers that reproduce lines of second- and third-row elements. The results suggest that care should be taken in using third- and fourth-row ions to constrain the physical conditions in photoionized X-ray plasmas until accurate DR rates are available. This underscores the importance of atomic physics in interpreting astronomical spectroscopy.
Information revelation and certification intermediaries

I discuss the role of intermediaries that search out the information of privately informed parties and then choose what to reveal to uninformed parties. The focus is on the strategic manipulation of information by these certification intermediaries. I show that in a class of environments the optimal choice for a monopoly intermediary is to reveal only whether quality is above some minimal standard. Despite this minimal information transmission, the intermediary can capture a large share of the surplus. I also show that competition among the intermediaries can lead to full information revelation.
Structure of Lithium Nitride and Transition-Metal-Doped Derivatives, Li3-x-yMxN (M = Ni, Cu): A Powder Neutron Diffraction Study

Structures of lithium nitride (α-Li3N) and ternary nitridometalates Li3-x-yMxN (M = Ni, Cu) have been refined from time-of-flight powder neutron diffraction data using the Rietveld method. The parent binary nitride was synthesized by reaction of lithium metal with nitrogen using liquid sodium as a solvent. The ternary nitrides were prepared by reaction of Li3N with the respective transition metals under nitrogen. Refined data confirm the hexagonal structure previously reported by single-crystal X-ray diffraction for lithium nitride (P6/mmm, a = 3.6576(1) A, c = 3.8735(1) A, Z = 1) and show that the α-Li3N phase contains close to 3% Li vacancies at room temperature. The substituted nitridometalates, Li1.36Ni0.79N and Li2.21Cu0.40N, both form structures analogous to α-Li3N (P6/mmm, a = 3.7697(1) A, c = 3.5270(1) A and a = 3.6791(1) A, c = 3.7725(1) A, respectively) in which the transition metal is disordered with Li between [Li2-yN] planes and Li vacancies are disordered within these planes. The nickel and ...
Observation of the anisotropy in arrival direction of cosmic rays with IceCube

The IceCube Neutrino Observatory is a kilometer-scale detector currently under construction at the South Pole. In its final configuration the detector will comprise 5160 Digital Optical Modules (DOMs) deployed on 86 strings between 1.5–2.5 km deep within the ice. While still incomplete, the detector has already recorded tens of billions of cosmic ray muons with a median energy of 20 TeV. This large sample has been used to study the arrival direction distribution of the cosmic rays. We report the observation of an anisotropy in the cosmic rays arrival direction at two different angular scales. The observed large scale anisotropy seems to be a continuation of similar structures observed in the Northern Sky by several experiments. IceCube observes also significant features on the angular scale of 20° – 30° that might be part of the larger scale structure.
Characteristic Time Correlations of Pollutant Emissions from an Annular Gas Turbine Combustor

The continuing development of a characteristic time model for gaseous pollutant emissions from conventional gas turbine engines is described. The new engine studied here is the Pratt & Whitney JT9D, and it is shown that universal correlations can be obtained by comparison with previous results. Since heterogeneous effects are found negligible for the data which were used in the present study, NO and CO emissions indices are correlated in terms of ratios of fluid mechanic and chemical kinetic times. Current limitations of the modeling approach are detailed.
Expected Detection and False Alarm Rates for Transiting Jovian Planets

Ground-based searches for transiting Jupiter-sized planets have so far produced few detections of planets but many of stellar systems with eclipse depths, durations, and orbital periods that resemble those expected from planets. The detection rates prove to be consistent with our present knowledge of binary and multiple-star systems and of Jovian-mass extrasolar planets. Space-based searches for transiting Earth-sized planets will be largely unaffected by the false alarm sources that afflict ground-based searches, except for distant eclipsing binaries whose light is strongly diluted by that of a foreground star. A by-product of the rate estimation is evidence that the period distribution of extrasolar planets is depressed for periods between 5 and 200 days.