cssi/SciSciGPT-SciSciNet huggingface dataset:
Finance and the Business Cycle: International, Inter-Industry Evidence

By considering yearly production growth rates for several manufacturing industries in more than 100 countries during (roughly) the last 40 years, we show that industries that are more dependent on external finance are hit harder during recessions. The observed difference in the behavior of industries is larger when financial frictions are thought to be more prevalent, linking the result directly to the financial mechanism hypothesis. In particular, more dependent industries are more strongly affected in recessions when they are located in countries with poor financial contractibility, and when their assets are softer or less protective of financiers. THERE IS A LARGE LITERATURE THAT STUDIES the effect of a country's financial de- velopment on the growth rate of output (see Levine (1997) for a survey). The overall conclusion of this literature is that financial markets and institutions have a positive and significant effect on long-run growth. Effort has been made toward establishing that causality goes effectively from financial to economic development and not the other way around. In particular, some recent papers analyze industry- and firm-level data in order to clarify the mechanisms that are sometimes obscured in cross-country studies (Demirg ¨ uc ¸-Kunt and Maksi- movic (1998), Rajan and Zingales (1998)). These papers show that financial development helps firms to grow faster by supplying more external funds; the effect is particularly strong among firms or industries that typically need more external funds to finance their investments. So far, the financial development literature has focused on long-run growth, for example a span of 10 or more years. We focus instead on short-run fluctu- ations in production and on how financial frictions amplify them. Our focus on short-run fluctuations is motivated by the fact that, besides allocating resources for long-term investment, financial systems pool, and diversify risks and pro- vide liquidity. A long tradition, going back as far as Fisher (1933), points out the importance of finance in the propagation (and perhaps as the starting point) of business cycles. This idea is called the credit channel of the business cycle and
Surface Ages and Resurfacing Rates of the Polar Layered Deposits on Mars

Interpretation of the polar stratigraphy of Mars in terms of global climate changes is complicated by the significant difference in surface ages between the north and south polar layered terrains inferred from crater statistics. We have reassessed the cratering record in both polar regions using Viking Orbiter and Mariner 9 images. No craters have been found in the north polar layered terrain, but the surface of most of the south polar layered deposits appears to have been stable for many of the orbital/axial cycles that are thought to have induced global climate changes on Mars. The inferred surface age of the south polar layered deposits (about 10 Ma) is two orders of magnitude greater than the surface age of the north polar layered deposits and residual cap (at most 100 ka). Similarly, modeled resurfacing rates are at least 20 times greater in the north than in the south. These results are consistent with the hypotheses that polar layered deposit resurfacing rates are highest in areas covered by perennial ice and that the differences in polar resurfacing rates result from the 6.4 km difference in elevation between the polar regions. Deposition on the portion of the south polar layered deposits that is not covered by the perennial ice cap may have ceased about 5 million years ago when the obliquity of Mars no longer exceeded 40°.
Pediatric Lung Transplantation

Lung transplantation in children is an effective treatment for end-stage pulmonary disease after all medical therapy has failed. It requires a huge investment in resources and absolute commitment on the part of the parents and patients. In spite of all these efforts and expense, the results with pediatric lung transplantation are the worst of all solid organ transplants. Much lies ahead to overcome the obstacles faced to improve this therapy.
From colonialism to neoliberalism: Critical reflections on Philippine mining in the “long twentieth century”

Abstract Through an analysis of archival data and findings from interviews with industry leaders, I explore the genesis, rise, and fall of the various Philippine mineral regimes of the twentieth century. Specifically, I examine the background of successive and overlapping colonial and neocolonial powers in three eras: late colonial (1901–1941), national developmental (1945–1964), and state authoritarianism (1965–1985). I also briefly examine the current neoliberal mineral regime (1986–present). I argue that, to date, capitalist enterprises and neocolonial powers have pursued two contradictory paths to extract precious (gold and silver) and base (chromite, iron, copper, nickel, magnesium, and ore) metals in the Philippines. On the one hand, mining companies appropriated expansive land, underpriced labor and inexpensive food to subsidize capital expenditure and mineral operations. The appropriation of basic inputs – or what is referred to as “cheap natures” – allowed these companies to reduce their sunken investments and operational costs. But on the other hand, as the sector developed more, it became increasingly difficult to appropriate such “cheap natures.” While initially profitable because of successful appropriation of “cheap natures,” companies eventually experienced decreasing returns because of the problems this caused.
Law, history and lessons in the CRISPR patent conflict

Predicting the outcome of the ongoing patent disputes surrounding genome-editing technology is equal parts patent analysis and history.
A study of the dynamics of UV laser photolysis of NOCl and NOBr

The photodissociation of NOCl and NOBr using lasers operating at 193 (ArF), 249 (KrF), 308 (XeCl), and 337 nm(N2) has been studied under collisionless conditions by measuring the infrared fluorescence of the NO product. Little difference between the results for NOBr and NOCl was observed and all results indicate a linear dependence of photodissociation yield on laser power. The extent of NO vibrational excitation observed was quite large in photodissociation utilizing the ArF and KrF laser lines, with states up to v≥16 observed with ArF and up to v≥14 with KrF. The XeCl and N2 lines produced much less NO excitation, up to v≥5. Statistical, half‐collision, and Franck–Condon models of the photodissociation dynamics were studied, with best agreement with experiment for dissociation at 193 and 249 nm being obtained using a Franck–Condon model. An excited potential function for NOCl in which the NO properties were taken to be close to that of NO(4Π) was found to predict the shape of the dissociated NO vibrational distribution accurately at both 193 and 249 nm. Photolysis at 308 and 337 nm could also be explained by a Franck–Condon model using the NO(A 2Π) state to model the NOCl excited state.
Intraluminal fiber-optic Doppler imaging catheter for structural and functional optical coherence tomography

We describe a miniature fiber-optic Doppler imaging catheter for integrated functional and structural optical coherence tomography (OCT) imaging. The Doppler catheter can map blood flow within a vessel as well as image vessel wall structures. A prototype Doppler catheter has been developed and demonstrated for measuring the intraluminal velocity profile in a vessel phantom (conduit). A simple mathematical model is demonstrated to estimate the total flow rate. This estimation technique also enables the spatial range of flow measurements to be extended by approximately two times the normal OCT image-penetration depth. The Doppler OCT catheter could be a powerful device for cardiovascular imaging.
Complete markets with discontinuous security price

A parameterized family of financial market models is presented. These models have jumps intrinsic to the price processes yet have strict completeness, equivalent martingale measures, and no arbitrage. For each value of the parameter \(\beta (-2\leq\beta <0)\) the model is just as rich as the standard model using white noise (Brownian motion) and a drift; moreover as \(\beta\) increases to zero the model converges weakly to the standard model. A hedging result, analogous to the Karatzas-Ocone-Li theorem, is also presented.
A Dynamic Complex of Signaling Proteins Uses Polar Localization to Regulate Cell-Fate Asymmetry in Caulobacter crescentus

Cellular asymmetry is critical to metazoan development and the life cycle of many microbes. In Caulobacter, cell cycle progression and the formation of asymmetric daughter cells depend on the polarly-localized histidine kinase CckA. How CckA is regulated and why activity depends on localization are unknown. Here, we demonstrate that the unorthodox kinase DivL promotes CckA activity and that the phosphorylated regulator DivK inhibits CckA by binding to DivL. Early in the cell cycle, CckA is activated by the dephosphorylation of DivK throughout the cell. However, in later stages, when phosphorylated DivK levels are high, CckA activation relies on polar localization with a DivK phosphatase. Localization thus creates a protected zone for CckA within the cell, without the use of membrane-enclosed compartments. Our results reveal the mechanisms by which CckA is regulated in a cell-type-dependent manner. More generally, our findings reveal how cells exploit subcellular localization to orchestrate sophisticated regulatory processes.
A general algorithm for limit solutions of plane stress problems

Abstract A computational approach to limit solutions is considered most challenging for two major reasons. A limit solution is likely to be non-smooth such that certain non-differentiable functions are perfectly admissible and make physical and mathematical sense. Moreover, the possibility of non-unique solutions makes it difficult to analyze the convergence of an iterative algorithm or even to define a criterion of convergence. In this paper, we use two mathematical tools to resolve these difficulties. A duality theorem defines convergence from above and from below the exact solution. A combined smoothing and successive approximation applied to the upper bound formulation perturbs the original problem into a smooth one by a small parameter e. As e → 0, the solution of the original problem is recovered. This general computational algorithm is robust such that from any initial trial solution, the first iteration falls into a convex hull that contains the exact solution(s) of the problem. Unlike an incremental method thut invariably renders the limit problem ill-conditioned, the algorithm is numerically stable. Limit analysis itself is a highly efficient concept which bypasses the tedium of the intermediate elastic-plastic deformation and seeks the most important information directly. With the said algorithm, we have produced many limit solutions of plane stress problems. Certain non-smooth characters of the limit solutions are shown in the examples presented. Two well-known as well as one parametric family of yield functions are used to allow comparison with some classical solutions.
Implications and mitigation of model mismatch and covariance contamination for hyperspectral chemical agent detection

Most chemical gas detection algorithms for long-wave infrared hyperspectral images assume a gas with a perfectly known spectral sig- nature. In practice, the chemical signature is either imperfectly measured and/or exhibits spectral variability due to temperature variations and Beers law. The performance of these detection algorithms degrades fur- ther as a result of unavoidable contamination of the background covari- ance by the plume signal. The objective of this work is to explore robust matched filters that take the uncertainty and/or variability of the tar- get signatures into account and mitigate performance loss resulting from different factors. We introduce various techniques that control the selec- tivity of the matched filter and we evaluate their performance in standoff LWIR hyperspectral chemical gas detection applications. © 2013 Society of
A Model for Abundances in Metal-poor Stars

A model is presented that seeks to explain quantitatively the stellar abundances of r-process elements and other elements associated with the r-process sites. It is argued that the abundances of all these elements in stars with -3 ≾[Fe/H] 130) r-elements but no Fe (presumably leaving behind black holes). The L events are of low frequency and produce Fe and dominantly light (A ≾ 130) r-elements (essentially none above Ba). By using the observed abundances in two ultra-metal-poor stars and the solar r-abundances, the initial or prompt inventory of elements produced by the first generations of very massive stars and the yields of H and L events can be determined. The abundances of a large number of elements in a star can then be calculated from the model by using only the observed Eu and Fe abundances. To match the model results and the observational data for stars with -3 < [Fe/H] < -1 requires that the solar r-abundances for Sr, Y, Zr, and Ba must be significantly increased from the standard values. No such changes appear to be required for all other elements. If the changes in the solar r-abundances for Sr, Y, Zr, and Ba are not permitted, the model fails at -3 < [Fe/H] < -1 but still works at [Fe/H] ≈ -3 for these four elements. By using the corrected solar r-abundances for these elements, good agreement is obtained between the model results and data over the range -3 < [Fe/H] < -1. No evidence of s-process contributions is found in this region, but all the observational data in this region now show regular increases of Ba/Eu above the standard solar r-process value. Whether the solar r-components of Sr, Y, Zr, and Ba used here to obtain a fit to the stellar data can be reconciled with those obtained from solar abundances by subtracting the s-components calculated from models is not clear.
Survival analysis of endometrial cancer patients with cervical stromal involvement.

OBJECTIVE Stage II endometrial cancer is relatively uncommon. There is no consensus for appropriate adjuvant therapy in endometrial cancer patients with cervical stromal involvement (International Federation of Gynecology and Obstetrics [FIGO] stage II). This study investigates how adjuvant treatments and tumor characteristics influence overall survival (OS) and disease-free survival (DFS) in stage II patients in order to establish better treatment guidelines. METHODS This multi-institution, Institutional Review Board approved, study is a retrospective review of 40 endometrial cancer patients with cervical stromal involvement treated from 1993 to 2009. Kaplan-Meier estimates were used to evaluate OS and DFS. RESULTS OS was 85% at three years and 67% at five years. There were no significant differences in age, histology, depth of invasion, comorbid conditions, surgical staging or recurrence between patients who received radiation therapy (RT) and those who did not. However, patients with FIGO grade 1 cancers were less likely to receive RT (p=0.007). Patients treated with RT had a similar 5 year OS (n=33, 69%) to those treated with surgery only (n=7, 60%, p=0.746). There were no OS differences when evaluating by grade, histology, or depth of invasion between patients who did and did not receive RT. Four patients recurred: three were locoregional failures only, and one failed locally and distant. CONCLUSION Patients receiving RT had higher grade tumors. Despite this, OS was comparable between the RT and the no RT cohorts. Local failure was the predominant pattern of failure. Endometrial cancer patients with cervical stromal involvement likely receive better locoregional control with the addition of adjuvant RT and we continue to advocate for RT in most cases.
Electrochemical measurements on metal oxide electrodes—I. Zirconium dioxide

Abstract Electrochemical studies were conducted on ZrZrO2 electrodes as part of the program in this laboratory on the development of pH probes for use in high temperature/high pressure aqueous systmes. The influence of various methods of preparation of the oxide electrode on the open circuit potential (Voc) and flatband potential (Vfb) were investigated. Electrodes with low impedance had a Voc that exhibited a Nernstian response to pH (−59 mV/pH) at 23°C, and oxide electrodes with high impedance had a Voc tht was insensitive to pH. Because of the frequency dispersion in the Mott—Schottky plots and the exhaustion of the oxide, Vfb could not be determined for the ZrO2 films. The electrochemical results indicate that the ZrZrO2 electrodes as used in this study do not offer much prospect for monitoring the pH of aqueous solutions.
CaBr2 hydrolysis for HBr production using a direct sparging contactor

Abstract The calcium–bromine cycle being investigated is a novel continuous hybrid cycle for hydrogen production employing both heat and electricity. Calcium bromide (CaBr 2 ) hydrolysis generates hydrogen bromide (HBr) which is electrolyzed to produce hydrogen. The CaBr 2 hydrolysis at 1050 K (777 °C) is endothermic with the heat of reaction δ G T = 181.5 KJ/mol (43.38 kcal/mol) and the Gibbs free energy change is positive at 99.6 kJ/mol (23.81 kcal/mol). What makes this hydrolysis reaction attractive is both its rate and that well over half the thermodynamic requirements for water-splitting heat of reaction of δ G T = 285.8 KJ/mol (68.32 kcal/mol) are supplied at this stage using heat rather than electricity. Molten-phase calcium bromide reactors may overcome the technical barriers associated with earlier hydrolysis approaches using supported solid-phase calcium bromide studied in the Japanese UT-3 cycle. Before constructing the experiment two design concepts were evaluated using COMSOL™ multi-physics models; 1) the first involved sparging steam into a calcium-bromide melt, while 2) the second considered a “spray-dryer” contactor spraying molten calcium bromide counter-currently to upward-flowing steam. A recent paper describes this work [6] . These studies indicated that sparging steam into a calcium-bromide melt is more feasible than spraying molten calcium bromide droplets into steam. Hence, an experimental sparging hydrolysis reactor using a mullite tube (ID 70 mm) was constructed capable of holding 0.3–0.5 kg (1.5–2.5 × 10 −3 kg mol) CaBr 2 forming a melt with a maximum 0.08 m (8 cm) depth. Sparging steam at a steam rate of 0.02 mol/mol of CaBr 2 per minute (1.2–2.3 × 10 −5 kg/s), into this molten bath promptly yielded HBr in a stable operation that converted up to 25% of the calcium bromide. The kinetic constant derived from the experimental data was 2.17 × 10 −12 kmol s −1 m −2 MPa −1 for the hydrolysis reaction. The conversion rate is highly dependent on melt depth and the design for steam sparging. This experimental data provides a basis for designing a larger-scale sparging hydrolysis reactor for the calcium bromide thermochemical cycle where the endothermic heat of reaction can be effectively supplied by heat transfer coils embedded in the melt.
Nilpotent orbits in the dual of classical Lie algebras in characteristic 2 and the Springer correspondence

Let $G$ be a simply connected algebraic group of type $B,C$ or $D$ over an algebraically closed field of characteristic 2. We construct a Springer correspondence for the dual vector space of the Lie algebra of $G$. In particular, we classify the nilpotent orbits in the duals of symplectic and orthogonal Lie algebras over algebraically closed or finite fields of characteristic 2.
Optimizing Computer System Configurations

We present a quantitative method for selecting optimum configurations of computer systems. For each con- figuration we specify a set of requirements reflecting user's needs. The level of satisfaction of requirements is called the global preference score. Using this indicator and the total cost of each configuration we solve the following optimization problems: (1) select a configuration which maximizes the global preference score for a constrained cost of computer system, (2) select a configuration which attains a given level of global preference for a minimum cost, and (3) select a configuration which attains the maximum global preference/cost ratio. We first present the optimization method and then a complete case study of computer optimization.
Size effects in metal foam cores for sandwich structures

The shear response of aluminum foam, including size effects, is measured and quantified for a closed-cell aluminum foam. The shear stiffness is shown to depend linearly on density, whereas the strength exhibits a power law dependence. The linear response is shown to be independent of strain rate up to rates of 0.17/s, whereas the strength and energy absorption increase with increasing strain rate. The density dependence of the stiffness is reproduced analytically based on the composite cylinders model. Optical techniques are used to measure the strain field of the experimental specimens throughout the loading program. By evaluation of concentric subregions of the sample, a sample size of 18 mean cell diameters is determined to be the dimension below which the uncertainty in the predicted shear modulus of an aluminum foam sample increases significantly. This length scale threshold is replicated in a periodic finite element structure with randomly distributed imperfections. I. Introduction M ETAL foams represent an attractive alternative for sandwich structure cores for multiple reasons. First, with metal foam cores, the adhesive substrate of a sandwich structure may be eliminated with in-production integral bonding to metallic face sheets, stiffening the sandwich and broadening its range of operating environments. Second, metal foams exhibit a compressive stress‐strain response that is ideal for energy absorption and impact alleviation with a long, constant stress, plastic strain plateau. 1 Third, an opencell metal foam offers an opportunity to eliminate the catastrophic nature of water or cryogenic gas permeation that has crippled the long-term use of sandwich constructions with honeycomb cores. 2 Fourth, an open-cell construction also allows for active cooling of the sandwich structure, elevating its range of acceptable operating temperatures. For integration into sandwich structures, the shear behavior of metal foam must be understood. Some disparate results regarding shear behavior currently exist in the literature. One study found a linear relationship between shear strength and density, 3 whereas a cubic lattice model subjected to shear loading predicted a nonlinear power law dependence. 4 Another investigation offers only a few data points for shear stiffness and strength of melt-foamed aluminum. 5 Furthermore, these experiments involved thin specimens, with no account for size effects. The present paper offers the full shear response curves for a broad range of density. The density dependence of stiffness and strength are found experimentally with the former being reproduced analytically. The strain rate dependence of the shear response is also considered. The effect of specimen size, relative to the mean cell size, is analyzed experimentally with a unique approach involving digital image correlation. The observed behavior is reproduced with a finite element model. These analyses identify a threshold in the ratio of specimen size to cell size, below which the shear response of a given sample is associated with a significant amount of uncertainty.
The Fate of the First Galaxies. I. Self-consistent Cosmological Simulations with Radiative Transfer

In cold dark matter (CDM) cosmogonies, low-mass objects play an important role in the evolution of the universe. Not only are they the first luminous objects to shed light in a previously dark universe, but if their formation is not inhibited by their own feedback, they dominate the galaxy mass function until redshift z ~ 5. In this paper we present and discuss the implementation of a three-dimensional cosmological code that includes most of the needed physics to simulate the formation and evolution of the first galaxies with a self-consistent treatment of radiative feedback. The simulation includes continuum radiative transfer using the optically thin variable Eddington tensor (OTVET) approximation and line radiative transfer in the H2 Lyman-Werner bands of the background UV radiation. We include detailed chemistry for H2 formation/destruction, molecular and atomic cooling/heating processes, ionization by secondary electrons, and heating by Lyα resonant scattering. We find that the first galaxies ("small-halo galaxies") are characterized by bursting star formation, self-regulated by a feedback process that acts on cosmological scales. The mass in stars produced by these objects can exceed the mass in stars produced by normal galaxies; therefore, their impact on cosmic evolution cannot be neglected. The main focus of this paper is on the methodology of the simulations, and we only briefly introduce some of the results. An extensive discussion of the results and the nature of the feedback mechanism are the focus of a companion paper.
A rationality conjecture about Kontsevich integral of knots and its implications to the structure of the colored Jones polynomial

Abstract We formulate a conjecture about the structure of the Kontsevich integral of a knot. We describe its value in terms of the generating functions for the numbers of external edges attached to closed 3-valent diagrams. We conjecture that these functions are rational functions of the exponentials of their arguments, their denominators being the powers of the Alexander–Conway polynomial. This conjecture implies the existence of an expansion of a colored Jones (HOMFLY) polynomial in powers of q−1 whose coefficients are rational functions of q α ( α being the color assigned to the knot). We show how to derive the first Kontsevich integral polynomial associated to the θ -graph from the rational expansion of the colored SU(3) Jones polynomial.
Vernon Smith: economics as a laboratory science

Vernon Smith shared the Nobel Prize in 2002 with Daniel Kahneman. This article surveys Smith’s contributions to economics. His early efforts led to greater understanding of markets and market institutions, which developed into important contributions to the design of new markets. Subsequent research focused on the complexity of behavior in simple games, including recent forays into “neuroeconomics”. The impact of his work on economic thinking and economic theory is substantial.
Gluon-gluon contributions to W+W− production and Higgs interference effects

In this paper we complete our re-assessment of the production of W boson pairs at the LHC, by calculating analytic results for the $ gg \to {W^{+} }{W^{-} } \to \nu {l^{+} }{l^{-} }\bar{\nu } $ process including the effect of massive quarks circulating in the loop. Together with the one-loop amplitudes containing the first two generations of massless quarks propagating in the loop, these diagrams can give a significant contribution with a large flux of gluons. One of the component parts of this calculation is the production of a standard model Higgs boson, gg → H and its subsequent decay, $ H \to {W^{+} }\left( { \to \nu {l^{+} }} \right){W^{-} }\left( { \to {l^{-} }\bar{\nu }} \right) $ . We will quantify the importance of the interference between the Higgs boson production process and the gluon-induced continuum production in the context of searches for the Higgs boson at the Tevatron and the LHC. For instance, for m H < 140 GeV the effect of the interference typically results in around a 10% reduction in the expected number of Higgs signal events. The majority of this interference is due to non-resonant contributions. Therefore cuts on the transverse mass such as those currently used by the ATLAS collaboration reduce the destructive interference to about a 1% effect. We advocate that a cut on the maximum transverse mass be used in future Higgs searches in this channel.
The pinched Veronese is Koszul

In this paper we prove that the coordinate ring of the pinched Veronese, k[X 3,X 2 Y,XY 2,Y 3,X 2 Z,Y 2 Z,XZ 2,YZ 2,Z 3], is Koszul. The result is obtained by combining the use of a flat deformation induced by a distinguished weight together with a generalization of the notion of Koszul filtrations.
Loop Equation and Area Law in Turbulence

The incompressible fluid dynamics is reformulated as dynamics of closed loops C in coordinate space. We derive explicit functional equation for the pdf of the circulation P c (Γ) which allows the scaling solutions in inertial range of spatial scales. The pdf decays as exponential of some power of Γ3/A 2 where A is the minimal area inside the loop.
Western Hemisphere Knowledge Partnerships

An overarching challenge of the 21st century is the pursuit of an economically equitable balance between an exponentially expanding human system on planet Earth and the finite system of renewable natural resources supporting that human system. The combination of rapidly growing human knowledge and revolutionary technologies for sharing knowledge provides an effective tool for addressing; (1) population growth and (2) gains in individual economic productivity that are driving expansion of the human system. An environmentally sustainable, economically equitable, and socially stable global society is within reach as an array of local and regional communities possessing those characteristics. Western Hemisphere Knowledge Partnerships offer an attractive way to demonstrate the potential of The Knowledge Age to mount an international response to this 21st century challenge.
INEX modeling of the Boeing ring optical resonator free electron laser

Abstract We present new results from the integrated numerical model of the accelerator/beam transport system and ring optical resonator of the Boeing free electron laser experiment. Modifications of the electron-beam transport have been included in a previously developed PARMELA model and are shown to reduce dramatically emittance growth in the 180° bend. The new numerically generated electron beam is used in the 3D FEL simulation code FELEX to calculate expected laser characteristics with the ring optical resonator and the 5 m untapered THUNDER wiggler. Performance sensitivity to optical cavity misalignments is studied.
Pssst... textual features... there is more to automatic essay scoring than just you

This study investigates a new approach to automatically assessing essay quality that combines traditional approaches based on assessing textual features with new approaches that measure student attributes such as demographic information, standardized test scores, and survey results. The results demonstrate that combining both text features and student attributes leads to essay scoring models that are on par with state-of-the-art scoring models. Such findings expand our knowledge of textual and non-textual features that are predictive of writing success.
Axioms for higher torsion invariants of smooth bundles

This paper attempts to explain the relationship between various characteristic classes for smooth manifold bundles which are known as ‘higher torsion’ classes. We isolate two fundamental properties that these cohomology classes may or may not have: additivity and transfer. We show that higher Franz-Reidemeister torsion and higher Miller-Morita-Mumford classes satisfy these axioms. Conversely, any characteristic class of smooth bundles satisfying the two axioms must be a linear combination of these two examples.We also show how any higher torsion invariant, that is, any characteristic class satisfying the two axioms, can be computed for a smooth bundle with a fiberwise Morse function with distinct critical values. Finally, we explain the statements of the conjectured formulas relating higher analytic torsion classes, higher Franz-Reidemeister torsion and Dwyer-Weiss-Williams smooth torsion.
Krull dimension for differential graded algebras

We introduce a naive notion of a system of parameters for a homologically finite complex over a commutative noetherian local ring and compare it to the system of parameters defined by Christensen. We show that these notions differ in general but that they agree when the complex in question is a DG R-algebra. In this case we also show that the Krull dimension defined in terms of the lengths of such systems of parameters agrees with Krull dimensions defined in terms of certain chains of prime ideals.
IBAR: Interacting boson model calculations for large system sizes

Abstract Scaling the system size of the interacting boson model-1 (IBM-1) into the realm of hundreds of bosons has many interesting applications in the field of nuclear structure, most notably quantum phase transitions in nuclei. We introduce IBAR, a new software package for calculating the eigenvalues and eigenvectors of the IBM-1 Hamiltonian, for large numbers of bosons. Energies and wavefunctions of the nuclear states, as well as transition strengths between them, are calculated using these values. Numerical errors in the recursive calculation of reduced matrix elements of the d-boson creation operator are reduced by using an arbitrary precision mathematical library. This software has been tested for up to 1000 bosons using comparisons to analytic expressions. Comparisons have also been made to the code PHINT for smaller system sizes. Program summary Program title: IBAR Catalogue identifier: AELI_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AELI_v1_0.html Program obtainable from: CPC Program Library, Queenʼs University, Belfast, N. Ireland Licensing provisions: GNU General Public License version 3 No. of lines in distributed program, including test data, etc.: 28 734 No. of bytes in distributed program, including test data, etc.: 4 104 467 Distribution format: tar.gz Programming language: C++ Computer: Any computer system with a C++ compiler Operating system: Tested under Linux RAM: 150 MB for 1000 boson calculations with angular momenta of up to L = 4 Classification: 17.18, 17.20 External routines: ARPACK ( http://www.caam.rice.edu/software/ARPACK/ ) Nature of problem: Construction and diagonalization of large Hamiltonian matrices, using reduced matrix elements of the d-boson creation operator. Solution method: Reduced matrix elements of the d-boson creation operator have been stored in data files at machine precision, after being recursively calculated with higher than machine precision. The Hamiltonian matrix is calculated and diagonalized, and the requested transition strengths are calculated using the eigenvectors. Restrictions: The 1000 boson coefficients for L = 0 and L = 20 have been included in the IBAR distribution and the 7.3 GB of data that make up the remaining coefficients for L = 21 to L = 2000 are available upon request. Running time: If the provided example is changed to include 100 bosons, the calculation requires about 1 second of run time. For 1000 bosons, the calculation requires about 9 minutes of run time.
The Flavor puzzle in multi-Higgs models

We reconsider the flavor problem in the models with two Higgs doublets. By studying two generation toy models, we look for flavor basis independent constraints on Yukawa couplings that will give us the mass hierarchy while keeping all Yukawa couplings of the same order. We then generalize our findings to the full three generation Standard Model. We find that we need two constraints on the Yukawa couplings to generate the observed mass hierarchy, and a slight tuning of Yukawa couplings of order 10%, much less than the Standard Model. We briefly study how these constraints can be realized, and show how flavor changing currents are under control for \( K - \bar{K} \) mixing in the neardecoupling limit.
OverCode: Visualizing Variation in Student Solutions to Programming Problems at Scale

In MOOCs, a single programming exercise may produce thousands of solutions from learners. Understanding solution variation is important for providing appropriate feedback to students at scale. The wide variation among these solutions can be a source of pedagogically valuable examples and can be used to refine the autograder for the exercise by exposing corner cases. We present OverCode, a system for visualizing and exploring thousands of programming solutions. OverCode uses both static and dynamic analysis to cluster similar solutions, and lets teachers further filter and cluster solutions based on different criteria. We evaluated OverCode against a nonclustering baseline in a within-subjects study with 24 teaching assistants and found that the OverCode interface allows teachers to more quickly develop a high-level view of students' understanding and misconceptions, and to provide feedback that is relevant to more students' solutions.
An efficient synthesis of methyl 2,3-anhydro-α-d-ribofuranoside

Abstract An efficient synthesis of methyl 2,3-anhydro-α- d -ribofuranoside is reported. Its preparation is achieved via a four-step sequence from methyl 2,3,5-tri-O-benzoyl-α- d -arabinofuranoside in 74% overall yield.
Cassiopeia A and Its Clumpy Presupernova Wind

The observed shock wave positions and expansion in Cassiopeia A can be interpreted in a model of supernova interaction with a freely expanding stellar wind with a mass loss rate of ~2 × 10-5 M☉ yr-1 for a wind velocity of 10 km s-1. The wind was probably still being lost at the time of the supernova, which may have been of Type IIn or Type IIb. The wind may play a role in the formation of very fast knots observed in Cas A. In this model, the quasi-stationary flocculi (QSFs) represent clumps in the wind, with a density contrast of several 103 compared with the smooth wind. The outer, unshocked clumpy wind is photoionized by radiation from the supernova and is observed as a patchy H II region around Cas A. This gas has a lower density than the QSFs and is heated by nonradiative shocks driven by the blast wave. Denser clumps have recombined and are observed as H I compact absorption features toward Cas A.
Images of the Brownian sheet

An N-parameter Brownian sheet in R d maps a non-random compact set F in R N to the random compact set B(F) in R d . We prove two results on the image-set B(F): (1) It has positive d-dimensional Lebesgue measure if and only if F has positive (d 2 -dimensional capacity. This generalizes greatly the earlier works of J. Hawkes (1977), J.-P. Kahane (1985), and Khoshnevisan (1999). (2) If dim H F > d 2 then with probability one, we can find a finite number of points ζ 1 ,.....,ζ m ∈ R d such that for any rotation matrix θ that leaves F in ΡΝ+ one of the ζi's is interior to B(θF). In particular, B(F) has interior-points a.s. This verifies a conjecture of T. S. Mountford (1989). This paper contains two novel ideas: To prove (1), we introduce and analyze a family of bridged sheets. Item (2) is proved by developing a notion of "sectorial local-non-determinism (LND)." Both ideas may be of independent interest. We showcase sectorial LND further by exhibiting some arithmetic properties of standard Brownian motion; this completes the work initiated by Mountford (1988).
On a Diffusive Version of the Lifschitz–Slyozov–Wagner Equation

This paper is concerned with the Becker-Doring (BD) system of equations and their relationship to the Lifschitz-Slyozov-Wagner (LSW) equations. A diffusive version of the LSW equations is derived from the BD equations. Existence and uniqueness theorems for this diffusive LSW system are proved. The major part of the paper is taken up with proving that solutions of the diffusive LSW system converge in the zero diffusion limit to solutions of the classical LSW system. In particular, it is shown that the rate of coarsening for the diffusive system converges to the rate of coarsening for the classical system.
Linear Bellman combination for control of character animation

Controllers are necessary for physically-based synthesis of character animation. However, creating controllers requires either manual tuning or expensive computer optimization. We introduce linear Bellman combination as a method for reusing existing controllers. Given a set of controllers for related tasks, this combination creates a controller that performs a new task. It naturally weights the contribution of each component controller by its relevance to the current state and goal of the system. We demonstrate that linear Bellman combination outperforms naive combination often succeeding where naive combination fails. Furthermore, this combination is provably optimal for a new task if the component controllers are also optimal for related tasks. We demonstrate the applicability of linear Bellman combination to interactive character control of stepping motions and acrobatic maneuvers.
VACUUM UV CIRCULAR DICHROISM OF POLYSACCHARIDES

Polysaccharides are of great commercial and biological importance. At the molecular level they display a richness in structural and conformational variability, and helical structures are commonplace. Of the various experimental techniques applicable to the study of polysaccharide conformation, optical spectroscopy has been limited by the relatively high energy of the electronic excitations, the first excitation in unsubstituted saccharides being in the vacuum ultraviolet region. In the past decade, the development of VUV CD spectrometers, including the use of synchrotron radiation, has allowed the chiroptical properties of polysaccharides to be observed directly. In this brief review the major CD features of polysaccharides are summarized, and several applications are described illustrating the usefulness of VUV CD spectroscopy in the study of the polysaccharide conformation. Examples include the glucans, dextran and acetylated cellulose; the glycosaminoglycan, heparin; and the microbial polysaccharides, gellan and xanthan. A recently proposed quadrant rule which describes the sign of the 175 nm n-σ* polysaccharide CD band also is discussed. This rule is the first attempt to place the descriptionof polysaccharide VUV CD on a theoretical foundation.
A materials chemistry perspective on nanomagnetism

Nanomagnetism encompasses naturally occurring magnetic molecules and clusters as well as artificially structured low-dimensional magnetic materials. Basic research areas include the pursuit of novel interfacial magnetic coupling and spin-transport phenomena and creating new magnetic electronic architectures. In addition to the study of fundamental magnetic phenomena, nanomagnets may in the future form the basis of emerging technologies, such as in ultra-high density data storage media, ultra-strong permanent magnets, and biological and chemical sensing. Herein we highlight materials chemistry contributions to the quest for new magnetic functionalities, including the fabrication of surfactant-mediated magnetic particles and soft matter templates as platforms for hierarchically assembled hybrid magnetic materials. Nanomagnetism is positioned at the frontier between chemistry and magnetism. Devising methods to organize functional magnetic nanostructures draws on the unique strengths of a diverse materials chemistry community.
The strategic pursuit of moral credentials

Abstract Moral credentials establish one's virtue and license one to act in morally disreputable ways with impunity (Monin & Miller, 2001). We propose that when people anticipate doing something morally dubious, they strategically attempt to earn moral credentials. Participants who expected to do something that could appear racist (decline to hire a Black job candidate in Studies 1 and 2, or take a test that might reveal implicit racial bias in Study 3) subsequently sought to establish non-racist credentials (by expressing greater racial sensitivity in Studies 1 and 2, or by exaggerating how favorably they perceived a Black job candidate in Study 3). Consistent with prior research, a follow-up study revealed that the opportunity to establish such credentials subsequently licensed participants to express more favorable attitudes towards a White versus a Black individual. We argue that strategically pursuing moral credentials allows individuals to manage attributions about their morally dubious behavior.
Equilibrium properties of the plasma sheath with a magnetic field parallel to the wall

Abstract Motivated by the Magnetized Target Fusion (MTF), a systematic investigation of the equilibrium properties of a 1D plasma sheath with a magnetic field parallel to the wall was carried out using analytical theory and kinetic simulations. Initially uniform full Maxwellian plasma consisting of equal temperature collisionless electrons and ions is allowed to interact with a perfectly absorbing conducting wall, which charges positively due to large ions gyro-radii. The analysis of the steady-state plasma and field profiles reveals the importance of the relation between electron and ion thermal Larmor radii and plasma Debye length. In particular, the sheath width scaling, the details of the particle flows and the break-down of force balance components exhibit different behaviors in three possible regimes. Despite our primary motivation, the results in this paper can also be applicable to the divertor and the first wall of tokamaks.
WIDE-FIELD INFRARED SURVEY EXPLORER OBSERVATIONS OF YOUNG STELLAR OBJECTS IN THE WESTERN CIRCINUS MOLECULAR CLOUD

The Wide-field Infrared Survey Explorer has uncovered a population of young stellar objects (YSOs) in the Western Circinus molecular cloud. Images show the YSOs to be clustered into two main groups that are coincident with dark filamentary structure in the nebulosity. Analysis of photometry shows numerous Class I and II objects. The locations of several of these objects are found to correspond to known dense cores and CO outflows. Class I objects tend to be concentrated in dense aggregates, and Class II objects more evenly distributed throughout the region.
A 15-Kiloparsec X-Ray Disk in the Elliptical Galaxy NGC 1700

We present Chandra observations of the young elliptical galaxy NGC 1700. The X-ray isophotes are highly flattened between semimajor axes of 30'' and 80'', reaching a maximum ellipticity X ≈ 0.65 at 60'' (15 kpc). The surface brightness profile in the spectrally soft flattened region is shallower than that of the starlight, indicating that the emission comes from hot gas rather than stellar sources. The flattening is so extreme that the gas cannot be in hydrostatic equilibrium in any plausible potential. A likely alternative is that the gas has significant rotational support. A simple model, representing isothermal gas distributed about a particular angular momentum, can reproduce the X-ray morphology while staying consistent with stellar kinematics. The specific angular momentum of the gas matches that of the stars in the most isophotally distorted outer part of the galaxy, and its cooling time matches the time since the last major merger. We infer that the gas was acquired in that merger, which involved a preexisting elliptical galaxy with a hot interstellar medium. The hot gas carried the angular momentum of the encounter and has since gradually settled into a rotationally flattened cooling disk.
Strings as perturbations of evolving spin networks

Abstract One step in the construction of a background independent formulation of string theory is detailed, in which it is shown how perturbative strings may arise as small fluctuations around histories in a formulation of non-perturbative dynamics of spin networks due to Markopoulou. In this formulation the dynamics of spin network states and their generalizations is described in terms of histories which have discrete analogues of the causal structure and many fingered time of Lorentzian spacetimes. Perturbations of these histories turn out to be described in terms of spin systems defined on 2-dimensional timelike surfaces embedded in the discrete spacetime. When the history has a classical limit which is Minkowski spacetime, the action of the perturbation theory is given to leading order by the spacetime area of the surface, as in bosonic string theory. This map between a non-perturbative formulation of quantum gravity and a 1+1 dimensional theory generalizes to a large class of theories in which the group SU(2)_is extended to any quantum group or supergroup. It is argued that a necessary condition for the non-perturbative theory to have a good classical limit is that the resulting 1+1 dimensional theory defines a consistent and stable perturbative string theory.