cssi/SciSciGPT-SciSciNet huggingface dataset:
CO rovibrational emission as a probe of inner disk structure

We present an analysis of CO emission lines from a sample of T Tauri, Herbig Ae/Be, and transitional disks with known inclinations in order to study the structure of inner disk molecular gas. We calculate CO inner radii by fitting line profiles with a simple parameterized model. We find that, for optically thick disks, CO inner radii are strongly correlated with the total system luminosity (stellar plus accretion) and consistent with the dust sublimation radius. Transitional disk inner radii show the same trend with luminosity, but are systematically larger. Using rotation diagram fits, we derive, for classical T Tauri disks, emitting areas consistent with a ring of width ~0.15 AU located at the CO inner radius; emitting areas for transitional disks are systematically smaller. We also measure lower rotational temperatures for transitional disks, and disks around Herbig Ae/Be stars, than for those around T Tauri stars. Finally, we find that rotational temperatures are similar to, or slightly lower than, the expected temperature of blackbody grains located at the CO inner radius, in contrast to expectations of thermal decoupling between gas and dust.
Identification of treatment response with social interactions

This paper studies identification of potential outcome distributions when treatment response may have social interactions. Defining a person’s treatment response to be a function of the entire vector of treatments received by the population, I study identification when nonparametric shape restrictions and distributional assumptions are placed on response functions. An early key result is that the traditional assumption of individualistic treatment response is a polar case within the broad class of constant treatment response (CTR) assumptions, the other pole being unrestricted interactions. Important non-polar cases are interactions within reference groups and anonymous interactions. I first study identification under assumption CTR alone. I then strengthen this assumption to semi-monotone response. I next discuss derivation of these assumptions from models of endogenous interactions. Finally, I combine assumption CTR with statistical independence of potential outcomes from realized effective treatments. The findings both extend and delimit the classical analysis of randomized experiments.
The preparation and lithiation of 3,3-Diphenyl-1,1,2-tribromocyclopropane

Abstract 3,3-Diphenyl-1,1,2-tribromocyclopropane 4 was synthesized from benzophenone in three steps in an overall yield of 11.4%. Treatment of 4 with butyllithium in THF at low temperatures, generated 1-lithio- and 1,2-dilithiocyclopropenes which were characterized by their quenching products, 6, 8, 11, and 12.
Cimetidine as adjunctive treatment for acetaminophen overdose

The aim of this study was to determine if cimetidine in addition to N-acetylcysteine and standard supportive care provide additional hepatoprotection following acute acetaminophen poisoning. It was designed as a prospective study with alternate month treatment protocol, and the work was carried out at a regional certified poison information centre. For a 2-year period, consultations received by the Rocky Mountain Poison Center involving acute acetaminophen overdose patients with a serum level above the nomogram line, but who would not receive N-acetylcystine therapy until at least 8 h postingestion, were prospectively evaluated for adjunctive treatment with cimetidine. All patients received standard supportive therapy and N-acetylcysteine treatment. During odd numbered months, cimetidine 300 mg was administered intravenously every 6 h for the duration of N-acetylcysteine therapy. Forty-one cimetidine treated patients were compared to 66 patients in the control group. The peak measured AST levels (+/- s.e.) were 1259+/-330 and 1301+/-451 for the control and cimetidine treatment groups, respectively (P = 0.94). Fourteen of 64 patients (21%) in the control group and 8/41 patients (20%) in the cimetidine group developed an AST > 1000 IUL-1. There were no statistical differences between the cimetidine-treated and control groups when classified by AST 1000 IUL-1. The addition of cimetidine therapy to standard N-acetylcysteine treatment did not provide additional hepatoprotection in acutely acetaminophen poisoned patients when treatment was started later than 8 h post overdose.(ABSTRACT TRUNCATED AT 250 WORDS)
SOBOLEV MAPPINGS: LIPSCHITZ DENSITY IS NOT A BI-LIPSCHITZ INVARIANT OF THE TARGET

We study a question of density of Lipschitz mappings in the Sobolev class of mappings from a closed manifold into a singular space. The main result of the paper, Theorem 1.7, shows that if we change the metric in the target space to a bi-Lipschitz equivalent one, then the property of the density of Lipschitz mappings may be lost. Other main results in the paper are Theorems 1.2, 1.3, 1.6, 1.8.
The Race to the Bottom, from the Bottom

The dominant perspective in discussions of labour and environmental standards and globalization is that of North–South competition and its impact on Northern standards. This paper presents an alternative perspective, that of South–South competition to export to the North and its impact on Southern standards. It develops a simple model of Southern competition, and demonstrates that whether a Southern race to the bottom is possible depends intricately on the Northern demand curve, the size of large exporters relative to each other and the relative size of the competitive fringe of small exporters. The possibility that Northern trade protectionism may undermine Southern standards is also examined.
Three routes to jet collimation by the Balbus–Hawley magnetorotational instability

Three completely different lines of work have recently led to the conclusion that the magnetorotational instability (MRI) may create a hoop stress that collimates jets. One argument is based upon consideration that magnetohydrodynamic (MHD) turbulence, in general, and turbulence driven by the MRI, in particular, is more nearly viscoelastic than it is viscous. Another argument is based upon the dispersion relation for the MRI in the context of 1 D simulations of core collapse. Yet a third argument rests in the results of direct numerical MHD simulations of collapsars and thick accretion flows. I elaborate on my previous work regarding the first argument above and I briefly discuss how these three sets of results are all related. I also discuss the different roles played by the magnetic tension and the magnetic pressure within the context of this work. I point out that this leads to consideration of the normal stress difference between the hoop stress and the radial stress, in preference to a focus on just the hoop stress itself. Additionally, I argue that simulations of thick accretion flows and collapsars are not self-consistent if they include a phenomenological model for an MRI-induced viscous stress but disregard these other MRI-induced stress components. I comment briefly on the RHESSI observation of polarization in the gamma-ray burst GRB0212206.1 argue that this polarization is consistent with a tangled field, and does not require a large-scale organized field. Finally, I suggest that the role of magnetic fields in creating jets, as described here, should be understood not to work within the confines of magnetocentrifugal models of jets, but rather as an alternative to them.
Polymerization of Butadiene with Alkylaluminum and Cobalt Chloride

Abstract The diethylaluminum chloride combination with cobaltous chloride or cobaltous chloride pyridinates requires water in a certain mole ratio to the diethylaluminum chloride to activate them as catalysts for butadiene polymerization at 5° C to 98% cis-1,4 structure. The cobalt-pyridine complex is the preferred component because of its ability to function in trace amounts. Several organic derivatives of water failed as substitutes. However, aluminum trichloride is effective as a substitute for water on an equimolar basis. The cis-1,4 content in the polymer decreases at higher polymerization temperatures. The higher pyridinates of cobaltous chloride tend to reduce the polymer molecular weight within narrow limits. The preferred solvent is benzene, in which the concentration of the monomer is a factor in both microstructure and polymer molecular weight. Certain mixtures of benzene and hexane provide another means of controlling molecular weight. The rate of polymerization is linear with respect to time ...
The accuracy of the clock synchronization achieved by TEMPO in Berkeley UNIX 4.3BSD

The authors discuss the upper and lower bounds on the accuracy of the time synchronization achieved by the algorithm implemented in TEMPO, the distributed service that synchronizes the clocks of the University of California, Berkeley, UNIX 4.3BSD systems. The accuracy is shown to be a function of the network transmission latency; it depends linearly upon the drift rate of the clocks and the interval between synchronizations. TEMPO keeps the clocks of the VAX computers in a local area network synchronized with an accuracy comparable to the resolution of single-machine clocks. Comparison with other clock synchronization algorithms shows that TEMPO, in an environment with no Byzantine faults, can achieve better synchronization at a lower cost. >
A Maximum Likelihood Methodology for Clusterwise Linear Regression

This paper presents a conditional mixture, maximum likelihood methodology for performing clusterwise linear regression. This new methodology simultaneously estimates separate regression functions and membership inK clusters or groups. A review of related procedures is discussed with an associated critique. The conditional mixture, maximum likelihood methodology is introduced together with the E-M algorithm utilized for parameter estimation. A Monte Carlo analysis is performed via a fractional factorial design to examine the performance of the procedure. Next, a marketing application is presented concerning the evaluations of trade show performance by senior marketing executives. Finally, other potential applications and directions for future research are identified.
The Mass Function of Young Star Clusters in the "Antennae" Galaxies.

We determine the mass function of young star clusters in the merging galaxies known as the "Antennae" (NGC 4038/9) from deep images taken with the Wide Field Planetary Camera 2 on the refurbished Hubble Space Telescope. This is accomplished by means of reddening-free parameters and a comparison with stellar population synthesis tracks to estimate the intrinsic luminosity and age, and hence the mass, of each cluster. We find that the mass function of the young star clusters (with ages less, similar160 Myr) is well represented by a power law of the form psipMp~M-2 over the range 104 less, similarM less, similar106 M middle dot in circle. This result may have important implications for our understanding of the origin of globular clusters during the early phases of galactic evolution.
What Policies will Reduce Gender Schooling Gaps in Developing Countries: Evidence and Interpretation

Summary This paper considers evidence for the effects of policies on gender gaps in education, distinguishing between policies that are ostensibly gender neutral and those that explicitly target girls. The demand for girls’ schooling is often more responsive than boys’ to gender neutral changes in school distance, price, and quality, patterns which can be explained in a human capital investment model through assumptions about girls’ and boys’ schooling costs and returns. Among policies that target girls’ enrollments, price incentives to households or schools and the provision of female teachers appear to be effective. Other interventions hold promise but have not been the subject of rigorous evaluation, pointing to an important agenda for future research.
Microscopy and Spectroscopy on a Cell Phone

We have developed two attachments that transform a cell phone’s camera into either a microscope with 1.5 micron resolution or a spectrometer with a 5 nm spectral resolution. We show applications to medically relevant problems.
Flavor, compositeness, and dynamical breaking of supersymmetry

We should be taking advantage of recent gains in our nonperturbative understanding of supersymmetric gauge theories to find the “standard” model of of dynamical supersymmetry breaking, and possibly of flavor as well. As an illustration of the possibilities for understanding the flavor hierarchy, I describe a realistic, renormalizable, supersymmetric model with a compositeness scale of ∼ 1–3 TeV for the top quark, the left handed bottom quark, and the up-type Higgs. The top-Higgs Yukawa coupling is a dynamically generated strong interaction effect, and is naturally large, while the other Yukawa couplings are suppressed.
Description of the Argonne National Laboratory target making facility

Abstract A description is given of some recent developments at the target facility at Argonne National Laboratory. Highlights include equipment upgrades which enable us to provide enhanced capabilities for support of the Argonne Heavy-Ion Program. Work currently in progress is described and future prospects are discussed.
A three-dimensional impact-penetration algorithm with erosion

Abstract A new interaction algorithm for treating three-dimensional impact-penetration simulations with erosion is presented. This algorithm is based on interactions between slave nodes (projectile) and master elements (target) and no tracking of the sliding interfaces is needed. It employs an assembly of normals to identify the interface surface adaptively so that it can handle eroding elements in both the target and the penetrator. In the interaction algorithm, momentum is exchanged between interacting nodes so that the total momentum is conserved. Examples of three dimensional calculations are also given.
A Two‐Zone Model for Type I X‐Ray Bursts on Accreting Neutron Stars

We construct a two-zone model to describe hydrogen and helium burning on an accreting neutron star and use it to study the triggering of type I X-ray bursts. Although highly simplified, the model reproduces all of the bursting regimes seen in the more complete global stability analysis of Narayan & Heyl, including the delayed mixed burst regime. The results are also consistent with observations. At accretion rates /Edd 0.1, helium burning via the well-known thin-shell thermal instability triggers bursts. As increases, however, the triggering mechanism evolves from the fast thermal instability to a slowly growing overstability involving both hydrogen and helium burning. The competition between nuclear heating via the β-limited CNO cycle and the triple-α process on the one hand, and radiative cooling via photon diffusion and emission on the other, drives oscillations with a period approximately equal to the hydrogen burning timescale. If these oscillations grow, the gradually rising temperature in the helium layer will eventually provoke a thin-shell thermal instability and hence a delayed mixed burst. For /Edd 0.25, nuclear burning is stable and there are no bursts. Nearly all other theoretical models, including detailed time-dependent multizone calculations, predict that bursts should occur for all /Edd 1, in conflict both with our results and with observations. We suggest that this discrepancy arises from the assumed strength of the hot CNO cycle breakout reaction 15O(α, γ)19Ne in these other models. That observations agree much better with the results of Narayan & Heyl and our two-zone model, both of which neglect breakout reactions, may imply that the true 15O(α, γ)19Ne rate is smaller than assumed in previous investigations.
The Definitive Abundance of Interstellar Oxygen

Using the Goddard High Resolution Spectrograph (GHRS) onboard the Hubble Space Telescope, we have obtained high signal-to-noise (S/N) ratio echelle observations of the weak interstellar O I λ1356 absorption toward the stars γ Cas, Per, δ Ori, Ori, 15 Mon, τ CMa, and γ Ara. In combination with previous GHRS measurements in six other sight lines (ζ Per, ξ Per, λ Ori, < Ori, κ Ori, and ζ Oph), these new observations yield a mean interstellar gas-phase oxygen abundance (per 106 H atoms) of 106 O/H = 319 ± 14. The largest deviation from the mean is less than 18%, and there are no statistically significant variations in the measured O abundances from sight line to sight line and no evidence of density-dependent oxygen depletion from the gas phase. Assuming various mixtures of silicates and oxides, the abundance of interstellar oxygen tied up in dust grains is unlikely to surpass 106 O/H ≈ 180. Consequently, the GHRS observations imply that the total abundance of interstellar oxygen (gas plus grains) is homogeneous in the vicinity of the Sun and about two-thirds of the solar value of 106 O/H = 741 ± 130. This oxygen deficit is consistent with that observed in nearby B stars and similar to that recently found for interstellar krypton with GHRS. Possible explanations for this deficit include: (1) early solar system enrichment by a local supernova, (2) a recent infall of metal-poor gas in the local Milky Way, or (3) an outward diffusion of the Sun from a smaller Galactocentric distance.
Use of 2-aminopurine as a fluorescent tool for characterizing antibiotic recognition of the bacterial rRNA A-site

Spectroscopic and calorimetric techniques have been employed to characterize the impact of incorporation of the fluorescent base analog 2-aminopurine into the 1492 or 1493 position of an E. coli rRNA A-site model oligonucleotide, as well as the energetics and dynamics associated with recognition of this A-site model oligomer by aminoglycoside antibiotics. The results of these studies indicate that incorporation of 2AP into either the 1492 or 1493 position does not perturb the structure or stability of the host RNA or its aminoglycoside binding affinity. In addition, the results also highlight drug-induced reduction in the mobilities of the bases at both positions 1492 and 1493 as a potentially key determinant of bactericidal potency.
Synthesis of 5,6-Dihydrophenanthridine (DHPA) Sulfonamides and Subsequent Acid-Catalyzed Rearrangement to Diaryl Sulfones

Abstract As part of an ongoing investigation into the rearrangement of cyclic aryl aminesulfonanilides to diarylsulfones, a series of novel 5,6-dihydrophenanthridine (DHPA) sulfonamides were synthesized. Acid catalysts were used to rearrange them to DHPA arylsulfones.
A Thomistic defense of whole-brain death

Michel Accad critiques the currently accepted whole-brain criterion for determining the death of a human being from a Thomistic metaphysical perspective and, in so doing, raises objections to a particular argument defending the whole-brain criterion by Patrick Lee and Germain Grisez. In this paper, I will respond to Accad's critique of the whole-brain criterion and defend its continued validity as a criterion for determining when a human being's death has occurred in accord with Thomistic metaphysical principles. I will, however, join Accad in criticizing Lee and Grisez's proposed defense of the whole-brain criterion as potentially leading to erroneous conclusions regarding the determination of human death. Lay summary: Catholic physicians and bioethicists currently debate the legally accepted clinical standard for determining when a human being has died-known as the "wholebrain criterion"-which has also been morally affirmed by the Magisterium. This paper responds to physician Michel Accad's critique of the whole-brain criterion based upon St. Thomas Aquinas's metaphysical account of human nature as a union of a rational soul and a material body. I defend the whole-brain criterion from the same Thomistic philosophical perspective, while agreeing with Accad's objection to an alternative Thomistic defense of whole-brain death by philosophers Patrick Lee and Germain Grisez.
Stereochemistry in the Ene Reactions of Singlet Oxygen and Triazolinediones with Allylic Alcohols. A Mechanistic Comparison

The ene reaction of singlet oxygen with (Z)-4-methylpent-3-en-2-ol-2,5,5,5-d4 (1-OH-d4) in nonpolar solvents exhibits a 90% threo diastereoselectivity in the adduct derived from the major syn perepoxide intermediate, but also a moderate threo diastereoselectivity in the adduct derived from the minor anti perepoxide. Photooxygenation of 2,4-dimethylpent-3-en-2-ol (2) exhibits a significant solvent dependence in the syn/anti methyl stereoselectivity, with nonpolar solvents promoting syn methyl reactivity, while polar solvents promote anti methyl reactivity. These results are in agreement with a steering effect between hydroxyl and singlet oxygen in the rate-determining step of the reaction. N-Phenyltriazolinedione addition to the chiral allylic alcohol 4-methylpent-3-en-2-ol (1-OH) is highly threo diastereoselective in nonpolar solvents, with a solvent dependent variation in the threo/erythro ene products. On the other hand, the nonfunctionalized chiral alkene 2,4-dimethyl-2-hexene (1-Et) exhibits poor dias...
Estimation of blood vessel boundaries in X-ray images

A new approach to blood vessel boundary estimation is presented in this paper. By appropriately modeling the blood vessel as a dynamically evolving state vector, and by taking into account the Poisson statistics of the x-ray imaging noise, we arrive at a state-space system with a nonlinear measurement equation which includes non-Gaussian, nonadditive noise. Maximum a posteriori (MAP) smoothing equations are derived for the state vector describing the vessel, and the optimally smoothed state vector is found by a dynamic programming search. This method performs especially well in images with low signal-to-noise ratio and low sampling rate. The performance of the proposed method is demonstrated by the boundary estimates obtained by applying the algorithm to a simulated vessel and measurement data as well as to real vessel phantom measurement data at various SNRs.
The Stochastic Theory of Fluvial Landsurfaces

A stochastic theory of fluvial landsurfaces is developed for transport-limited erosion, using well-established models for the water and sediment fluxes. The mathematical models and analysis are developed showing that some aspects of landsurface evolution can be described by Markovian stochastic processes. The landsurfaces are described by nondeterministic stochastic processes, characterized by a statistical quantity, the variogram, that exhibits characteristic scalings. Thus the landsurfaces are shown to be self-organized critical (SOC) systems, possessing both an initial transient state and a stationary state, characterized by respectively temporal and spatial scalings. The mathematical theory of SOC systems is developed and used to identify three stochastic processes that shape the surface. The SOC theory of landsurfaces reproduces established numerical results and measurements from digital elevation models (DEMs).
Some ideas on data types in high-level languages

A number of issues are explored concerning the notion that a data type is a set of values together with a set of primitive operations on those values. Among these are the need for a notation for iterating over the elements of any finite set (instead of the more narrow for i := 1 to n notation), the use of the domain of an array as a data type, the need for a simple notation for allowing types of parameters to be themselves parameters (but in a restrictive fashion), and resulting problems with conversion of values from one type to another.
Determination of lead concentration and lead isotope ratios in calcium supplements by inductively coupled plasma mass spectrometry after high pressure, high temperature digestion

The presence of lead as a contaminant in calcium supplements has aroused considerable public health interest in recent years. In this investigation lead and lead isotope ratios were determined by ICP-MS in ten brands of calcium supplements after high pressure/temperature digestion. Calcium supplements (200 to 250 mg) were digested in 2 mL of nitric acid at 230 °C and at a pressure of 1770 psi (1.2 × 104 kPa). Lead concentrations were determined by matrix-matched lead standards prepared in a high-purity calcium carbonate matrix. Good recoveries of lead and calcium were obtained for certified animal bone reference material. High levels of Pb (8 to 28 μg Pb per g of calcium) were found in calcium supplements that contain dolomite or bone meal. Chelated and refined calcium supplements had lower Pb levels (0.8 to 0.9 μg Pb/g Ca). Application of lead isotope ratios to distinguish the origin of calcium sources was also explored.
Large-x connections of nuclear and high-energy physics

I discuss how global QCD fits of parton distribution functions (PDFs) can make the somewhat separated fields of high-energy particle physics and lower energy hadronic and nuclear physics interact to the benefit of both. I review specific examples of this interplay from recent works of the CTEQ-Jefferson Lab collaboration, including hadron structure at large parton momentum and gauge boson production at colliders. I devote particular attention to quantifying theoretical uncertainties arising in the treatment of large partonic momentum contributions to deep inelastic scattering (DIS) observables, and to discussing the experimental progress needed to reduce these.
Light Source Effects

The perception of surface luster in achromatic single view images seems to depend on the existence of regions with source-like properties, called here Light Source Effects. Light source effects are broken down into three categories according to gross aspects of the physical situation in which they occur, and criteria for detecting the regions they cause are suggested.
Modeling atmospheric effects of the September 1859 solar flare

[1] We have modeled atmospheric effects, especially ozone depletion, due to a solar proton event which probably accompanied the extreme magnetic storm of 1–2 September 1859. We use an inferred proton fluence for this event as estimated from nitrate levels in Greenland ice cores. We present results showing production of odd nitrogen compounds and their impact on ozone. We also compute rainout of nitrate in our model and compare to values from ice core data.
Differential rotation of photospheric magnetic fields associated with coronal holes

An interesting aspect of solar rotation is the fact that coronal holes seem to exhibit little or no differential rotation. The question is investigated of whether or not the photospheric magnetic fields underlying coronal holes also exhibit reduced differential rotation. In order to accomplish this, the daily positions of filaments and plages surrounding a large coronal hole that lasted for several disk passages were measured. The resulting differential-rotation curve was considerably flatter than the standard curve for long-lived filaments and was in remarkably good agreement with the curve found for the overlying coronal hole itself.
Trade-offs between selection complexity and performance when searching the plane without communication

We argue that in the context of biology-inspired problems in computer science, in addition to studying the time complexity of solutions it is also important to study the selection complexity, a measure of how likely a given algorithmic strategy is to arise in nature. In this spirit, we propose a selection complexity metric χ for the ANTS problem [Feinerman et al.]. For algorithm A, we define χ(A) = b + log l, where b is the number of memory bits used by each agent and l bounds the fineness of available probabilities (agents use probabilities of at least 1/2l). We consider n agents searching for a target in the plane, within an (unknown) distance D from the origin. We identify log log D as a crucial threshold for our selection complexity metric. We prove a new upper bound that achieves near-optimal speed-up of (D2/n +D) ⋅ 2O(l) for χ(A) ≤ 3 log log D + O(1), which is asymptotically optimal if l∈ O(1). By comparison, previous algorithms achieving similar speed-up require χ(A) = Ω(log D). We show that this threshold is tight by proving that if χ(A)
Nature versus Nurture: Luminous Blue Variable Nebulae in and near Massive Stellar Clusters at the Galactic Center

Three luminous blue variables (LBVs) are located in and near the Quintuplet Cluster at the Galactic center: the Pistol Star, G0.120-0.048, and qF362. We present imaging at 19, 25, 31, and 37 μm of the region containing these three LBVs, obtained with SOFIA using FORCAST. We argue that Pistol and G0.120-0.048 are identical "twins" that exhibit contrasting nebulae due to the external influence of their different environments. Our images reveal the asymmetric, compressed shell of hot dust surrounding the Pistol Star and provide the first detection of the thermal emission from the symmetric, hot dust envelope surrounding G0.120-0.048. However, no detection of hot dust associated with qF362 is made. Dust and gas composing the Pistol nebula are primarily heated and ionized by the nearby Quintuplet Cluster stars. The northern region of the Pistol nebula is decelerated due to the interaction with the high-velocity (2000 km s–1) winds from adjacent Wolf-Rayet Carbon (WC) stars. From fits to the spectral energy distribution (SED) of the Pistol nebula with the DustEM code we determine that the Pistol nebula is composed of a distribution of very small, transiently heated grains (10 to ~ 35 A) having a total dust mass of 0.03 M ☉, and that it exhibits a gradient of decreasing grain size from south to north due to differential sputtering by the winds from the WC stars. The total IR luminosity of the Pistol nebula is 5.2 × 105 L ☉. Dust in the G0.120-0.048 nebula is primarily heated by the central star; however, the nebular gas is ionized externally by the Arches Cluster. Unlike the Pistol nebula, the G0.120-0.048 nebula is freely expanding into the surrounding medium. A grain size distribution identical to that of the non-sputtered region of the Pistol nebula satisfies the constraints placed on the G0.120-0.048 nebula from DustEM model fits to its SED and implies a total dust mass of 0.021 M ☉. The total IR luminosity of the G0.120-0.048 nebula is ~105 L ☉. From Paschen-α and 6 cm observations we determine a total gas mass of 9.3 M ☉ and 6.2 M ☉ for the Pistol and G0.120-0.048 nebulae, respectively. Given the independent dust and gas mass estimates we find that the Pistol and G0.120-0.048 nebulae exhibit similar gas-to-dust mass ratios of and , respectively. Both nebulae share identical size scales (~0.7 pc) which suggests that they have similar dynamical timescales of ~104 yr, assuming a shell expansion velocity of v exp = 60 km s–1.
Quantal analysis of string-inspired lineal gravity with matter fields

Abstract We show that string-inspired lineal gravity interacting with matter fields cannot be Dirac-quantized owing to the well-known anomaly in energy-momentum tensor commutators.
Seasoned Equity Offers: The Effect of Insider Ownership and Float

Seasoned equity offering (SEO) underpricing has increased dramatically since the early 1980s. While previous research has examined the determinants of SEO underpricing, these studies have not explored the effect of insider ownership on discounts. We find that this effect is twofold. First, higher insider ownership reduces float, thereby increasing price pressure and SEO underpricing. This effect is greatest in firms with low liquidity. Second, the greater the percentage of secondary shares offered, the lower the underpricing, suggesting that manager's pressure banks to reduce underpricing when their personal wealth is at stake. However, we find that this negative relation is mitigated if the firm employs a prestigious underwriter.
Predictors and outcomes of contralateral prophylactic mastectomy among breast cancer survivors

Background Women affected with breast cancer who carry a BRCA1 or BRCA2 (BRCA1/2) mutation are at risk of developing contralateral breast cancer. To reduce the risk of contralateral breast cancer, some patients opt for prophylactic surgery of the unaffected breast (contralateral prophylactic mastectomy, CPM) in addition to mastectomy of the affected breast.
A surface‐renewal model for constant flux cross‐flow microfiltration

A mathematical model using classical cake-filtration theory and the surface-renewal concept is formulated for describing constant flux, cross-flow microfiltration (CFMF). The model provides explicit analytical expressions for the transmembrane pressure drop (TMP) and cake-mass buildup on the membrane surface as a function of filtration time. The basic parameters of the model are the membrane resistance, specific cake resistance, and rate of surface renewal. The surface-renewal model has two forms: the complete model, which accounts for cake compressibility; and a subsidiary model for incompressible cakes, which can be derived from the complete model. The subsidiary model is correlated against some of the experimental TMP data reported by Miller et al. (J Membrane Sci 2014, 452, 171) for constant flux CFMF of a soybean-oil emulsion in a cross-flow filtration cell having unmodified and surface-modified, fouling-resistant membranes, and has an average root-mean-square (RMS) error of 6.2%. The complete model is fitted to the experimental TMP data reported by Ho and Zydney (J Membrane Sci, 2002, 209, 363) for constant flux microfiltration of a bovine serum albumin solution in a stirred cell using polycarbonate track-etched membranes and has an average RMS error of 11.5%. This model is also correlated against the TMP data of Kovalsky et al. (J Membrane Sci 2009, 344, 204) for constant flux yeast filtration in a stirred cell (average RMS error = 9.2%). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41778.
The Spectrum of a Random Geometric Graph is Concentrated

Consider n points, x 1,... , x n , distributed uniformly in [0, 1] d . Form a graph by connecting two points x i and x j if $$\Vert x_i - x_j\Vert \leq r(n)$$ . This gives a random geometric graph, $$G({\mathcal {X}}_n;r(n))$$ , which is connected for appropriate r(n). We show that the spectral measure of the transition matrix of the simple random walk on $$G({\mathcal {X}}_n; r(n))$$ is concentrated, and in fact converges to that of the graph on the deterministic grid.
Has Moral Hazard Become a More Important Factor in Managerial Compensation

We estimate a principal-agent model of moral hazard with longitudinal data on firms and managerial compensation over two disjoint periods spanning 60 years to investigate increased value and variability in managerial compen sation. We find exogenous growth in firm size largely explains these secular trends in compensation. In our framework, exogenous firm size works through two channels. First, conflicts of interest between shareholders and managers are magnified in large firms, so optimal compensation plans are now more
THE RENT-PRICE RATIO FOR THE AGGREGATE STOCK OF OWNER-OCCUPIED HOUSING

We construct a quarterly time series of the rent-price ratio for the aggregate stock of owner-occupied housing in the United States, starting in 1960, by merging micro data from the last five Decennial Censuses of Housing surveys with price indexes for house prices and rents. We show that the rent-price ratio ranged between 5 and 5.5 percent between 1960 and 1995, but rapidly declined after 1995. By year-end 2006, the rent-price ratio reached a historic low of 3.5 percent. For the rent-price ratio to return to its historical average over, say, the next five years, house prices likely would have to fall considerably.
Targeted chemical upgrading of lignocellulosic biomass to platform molecules

This review presents an overview of the initial targeted chemical processing stages for conversion of lignocellulosic biomass to platform molecules that serve as intermediates for the production of carbon-based fuels and chemicals. We identify four classes of platform molecules that can be obtained in an initial chemical processing step: (i) sugars, (ii) dehydration products, (iii) polyols and (iv) lignin monomers. Special emphasis is placed on reporting and comparing parameters that affect process economics and/or sustainability, including product yields, amount of catalyst used, processing conditions, and product concentrations. We discuss the economic trade-offs associated with choices related to these parameters, depending on the product that is targeted. We also address the effects of real biomass on the ability to recover, recycle, and potentially regenerate catalysts and solvents used in the biomass conversion processes.
Lower Bounds on the Size of Semidefinite Programming Relaxations

We introduce a method for proving lower bounds on the efficacy of semidefinite programming (SDP) relaxations for combinatorial problems. In particular, we show that the cut, TSP, and stable set polytopes on n-vertex graphs are not the linear image of the feasible region of any SDP (i.e., any spectrahedron) of dimension less than 2nδ, for some constant δ > 0. This result yields the first super-polynomial lower bounds on the semidefinite extension complexity of any explicit family of polytopes.Our results follow from a general technique for proving lower bounds on the positive semidefinite rank of a matrix. To this end, we establish a close connection between arbitrary SDPs and those arising from the sum-of-squares SDP hierarchy. For approximating maximum constraint satisfaction problems, we prove that SDPs of polynomial-size are equivalent in power to those arising from degree-O(1) sum-of-squares relaxations. This result implies, for instance, that no family of polynomial-size SDP relaxations can achieve better than a 7/8-approximation for max-sat.
Implicit Sampling for Path Integral Control, Monte Carlo Localization, and SLAM

Implicit sampling is a recently developed variationally enhanced sampling method that guides its samples to regions of high probability, so that each sample carries information. Implicit sampling may thus improve the performance of algorithms that rely on Monte Carlo (MC) methods. Here the applicability and usefulness of implicit sampling for improving the performance of MC methods in estimation and control is explored, and implicit sampling based algorithms for stochastic optimal control, stochastic localization, and simultaneous localization and mapping (SLAM) are presented. The algorithms are tested in numerical experiments where it is found that fewer samples are required if implicit sampling is used, and that the overall runtimes of the algorithms are reduced.
Dynamic Preisach modelling of hysteresis for the piezoceramic actuator system

Rate-dependent hysteresis property is a common phenomenon in various hysteretic systems including the piezoceramic material system. Dynamic Preisach model is needed to describe the rate-dependent hysteresis. This paper proposes a new dynamic Preisach model by introducing the dependence of the Preisach function on the input variation rate. An input variation rate function was introduced to adjust the relationship of hysteresis loop on the input variation rate for different hysteresis systems. A detailed numerical implementation procedure is also presented. Experiments were conducted to study the hysteresis behavior of piezoceramic actuator system and to verify the proposed model.
Construction of Bulk Fields with Gauge Redundancy

We extend the construction of field operators in AdS as smeared single trace operators in the boundary CFT to gauge fields and gravity. Bulk field operators in a fixed gauge can be thought of as non-local gauge invariant observables. Non-local commutators result from the Gauss law constraint, which for gravity implies a perturbative notion of holography. We work out these commutators in a generalized Coulomb gauge and obtain leading order smearing functions in radial gauge.
Search for configurationally stable, aracemic α-amino organolithiums

Abstract The search for configurationally stable α-amino carbanions has led to an interesting observation of differing reactivity of diastereomeric organolithiums and to the characterization of aracemic 2-lithio-N-methylpiperidine and 2-lithio-N-methylpyrrolidine as configurationally stable α-aminoorganolithiums. Details for the preparation of these and related α-lithioheterocycles, evaluation of their chemical and configurational stability, and a preliminary evaluation of the stereoselectivity of their reactions with electrophiles is presented.
Galactic versus Extragalactic Pixel Lensing Events toward M31

A new type of gravitational microlensing experiment toward a field where stars are not resolved is being developed observationally and theoretically: pixel lensing. When the experiment is carried out toward the M31 bulge area, events may be produced both by massive compact halo objects (MACHOs) in our Galactic halo and by lenses in M31. We estimate that ~10%-15% of the total events are caused by Galactic halo MACHOs assuming an all-MACHO halo. If these Galactic events could be identified, they would provide us with an important constraint on the shape of the halo. We test various observ-ables that can be used for the separation of Galactic halo/M31 events. These observables include the Einstein timescale, the effective duration of an event, and the flux at the maximum amplification, but they cannot be used to separate the two populations of events. However, we find that most high maximum-flux Galactic halo events can be isolated through a satellite-based measurement of the flux difference caused by the parallax effect. For the detection of the flux difference, it is required to monitor events with an exposure time of ~20 minutes by a 0.5 m telescope mounted on a satellite. Such observations could be carried out as a minor component of a mission aimed primarily at events seen toward the Galactic bulge and the Large Magellanic Cloud. In addition, proper motion can be used to isolate Galactic halo/M31 events, but for only ~5% of high signal-to-noise ratio M31 events and only 1% of Galactic halo events.
Born Unequal: A Study of the Helpfulness of User-Generated Product Reviews

Abstract Online user-generated product reviews have become an indispensible tool for consumers and thus for retailers who want to attract and retain consumers. Yet, relatively little is known about what causes consumers to find an online peer review helpful to their shopping tasks. Prior research examines mostly the effects of product reviews on consumer product attitude, product choice, and product sales. This paper, however, provides an analysis of the determinants of review helpfulness. In two studies, we examine the effects of review characteristics, product type, and reviewer characteristics on perceived review helpfulness. With data collected from a real online retailer, we provide empirical evidence to support our conceptual predictions. Specifically, both review valence and length have positive effects on review helpfulness, but the product type (i.e., experiential vs. utilitarian product) moderates these effects. Using content analysis of reviews, we develop a measure of expressed reviewer innovativeness (i.e., the predisposition toward new products as revealed in review content). A curvilinear relationship exists between expressed reviewer innovativeness and review helpfulness. These findings lead to pertinent managerial implications.
Origin and relative age of lunar and Mercurian intercrater plains

Differences in the diameter/density distribution of craters in the size range 7-100 km between heavily cratered areas and areas of intercrater plains indicate the deposition of both lunar and Mercurian intercrater plains has preferentially obliterated craters not greater than about 30 km diameter. This obliteration has altered the original lunar population distribution function from about a -1.3 slope to about -0.7 slope. At least a significant portion of both the lunar and Mercurian intercrater plains appear to be volcanic deposits emplaced during the later stages of heavy bombardment on each body rather than basin ejecta or an ancient primordial surface. The very widespread distribution of intercrater plains on Mercury compared to the moon may be related to Mercury's core formation which would have resulted in a large radius increase leading to widespread extensional fracturing to provide egress for the eruption of volcanic deposits on a global scale. This was followed by a radius decrease due to contraction of the lithosphere to produce thrust faulting represented by Mercury's lobate scarps.
The Cancer Risk from Low Level Radiation

We present a wide variety of experimental data indicating that linear no-threshold theory (LNT) greatly exaggerates the cancer risk from low level radiation. LNT is based on cancer initiating hits on DNA molecules, but many other factors affect the progression from DNA damage to a fatal tumor, such as availability of DNA repair enzymes, immune response, and cell suicide. Data are presented to show that these are generally stimulated by low level radiation (LLR) and suppressed by high doses that serve as calibrations for LNT. Since the great majority of cancers are caused by natural chemical processes, the protection against these provided by LLR may make LLR beneficial rather than harmful. Genes turned on and turned off by LLR are often different from those affected by high doses. Direct studies of cancer risk vs dose are reviewed: animal experiments generally indicate that LNT exaggerates the risk of low level radiation, and the same is true of most data on humans except possibly where dose rates are very high. Data show that the time delay between receipt of dose and cancer death increases with decreasing dose, which means that, with low level radiation, death from natural causes will often occur first. This implies an effective threshold. Responses to this type of information by various official and prestigious groups charged with estimating cancer risks from radiation are reviewed.
Growth in Human Immunodeficiency Virus–Infected Children Receiving Ritonavir-Containing Antiretroviral Therapy

Objectives: To determine if age- and sex-adjusted growth z scores correlate with HIV-1 RNA level and if control of viral load for 48 and 96 weeks results in improved growth in children receiving highly active antiretroviral therapy. Design: Secondary analysis of the cohort of children receiving ritonavir nested in a randomized, open-label, clinical trial. Subjects and Methods: The Pediatric AIDS Clinical Trials Group Protocol 338 enrolled clinically stable, antiretroviral therapy–experienced, HIV-infected subjects aged 2 through 17 years. Using data from subjects randomized to ritonavir-containing regimens (n=197), the association of growth z scores and HIV-1 RNA levels were examined. Main Outcome Measures: Age- and sex-adjusted weight and height z scores. Results: Enrollment weights were comparable with ageand sex-adjusted norms, but subjects receiving ritonavircontaining antiretroviral therapy were significantly shorter (mean z score, �0.57 [29th percentile]; 95% confidence interval, �0.73 to �0.40). Higher HIV-1 RNA levels correlated with lower growth z scores (P.01). Subjects achieving and maintaining HIV-1 RNA of 400 copies/mL or less through 48 and 96 weeks experienced worse growth than subjects with a less controlled viral load. Conclusions: In this pediatric cohort, a significant decline in height and weight z scores was found despite control of viral replication. Further studies of growth are necessary to assess if nutritional and hormonal adjuvants to highly active antiretroviral therapy should be considered to improve growth in HIV-infected children.
A note on quantum products of Schubert classes in a Grassmannian

Given two Schubert classes ?? and ?μ in the quantum cohomology of a Grassmannian, we construct a partition ?, depending on ? and μ, such that ?? appears with coefficient 1 in the lowest (or highest) degree part of the quantum product ????μ. To do this, we show that for any two partitions ? and μ, contained in a k × (n ? k) rectangle and such that the 180?-rotation of one does not overlap the other, there is a third partition ?, also contained in the rectangle, such that the Littlewood-Richardson number c ?μ ? is 1.