cssi/SciSciGPT-SciSciNet huggingface dataset:
Fiscal Transparency, Fiscal Performance and Credit Ratings†

Fiscal transparency can provide policymakers with incentives to adopt better policies by enhancing the public debate on the design and sustainability of fiscal policy and establishing accountability for their implementation. Fiscal transparency can also reduce uncertainty about fiscal policy and fiscal outturns by providing more information on the underlying fiscal position and fiscal risks. Both effects suggest that countries should benefit from adopting transparency enhancing policies through better market assessments of their sovereign risk. In this paper, we investigate whether fiscal transparency has an effect on market perceptions of sovereign risk, as measured by sovereign credit ratings, and if so, through which channels. We find that fiscal transparency has a positive and significant effect on ratings – one standard deviation increase in fiscal transparency increases credit ratings by 0.7 and 1 notches (or steps in the credit rating scale) in advanced and developing economies, respectively – but its effect works through different channels in advanced and developing economies. In advanced economies, fiscal transparency is associated with better fiscal outcomes, leading indirectly to higher credit ratings. In developing economies, the direct uncertainty-reducing effect of fiscal transparency seems to be more important. Indeed, the effect of fiscal transparency on fiscal performance is found to increase with the level of institutional development.
Mental health in the aftermath of conflict

The authors survey the recent literature on the mental health effects of conflict. They highlight the methodological challenges faced in this literature, which include the lack of validated mental health scales in a survey context, the difficulties in measuring individual exposure to conflict, and the issues related to making causal inferences from observed correlations. They illustrate how some of these issues can be overcome in a study of mental health in post-conflict Bosnia and Herzegovina. Mental health is measured using a clinically validated scale; conflict exposure is proxied by administrative data on war casualties instead of being self-reported. The analysis suggests that there are no significant differences in overall mental health across areas which are affected by ethnic conflict to a greater or lesser degree.
Product market policies in Romania : a comparison with EU partners

Romania's European Union accession in 2007 has resulted in a substantial reduction of the formal barriers to integration with the European Union Single Market. This study takes stock of the progress by benchmarking product market policies in Romania to those of European Union countries, as measured by the OECD indicators of Product Market Regulation. These indicators allow for a comprehensive mapping of policies affecting competition in product markets. Comparison with European Union countries reveals that, for half of the policy areas covered by the study, Romania's product market policies are more restrictive of competition than most direct comparators in the region, whereas for other indicators Romania is on a par with the European Union average or has achieved best practice. Nonetheless, these results should be interpreted in light of the fact that the Product Market Regulation approach measures officially adopted policies and does not capture implementation. Future reforms should be directed both at improving official regulation and, where policies that favor competition are already in place, toward effective enforcement.
6D SCFTs and Gravity

We study how to couple a 6D superconformal field theory (SCFT) to gravity. In F-theory, the models in question are obtained working on the supersymmetric background $$ \mathbb{R} $$ 5,1 × B where B is the base of a compact elliptically fibered Calabi-Yau threefold in which two-cycles have contracted to zero size. When the base has orbifold singularities, we find that the anomaly polynomial of the 6D SCFTs can be understood purely in terms of the intersection theory of fractional divisors: the anomaly coefficient vectors are identified with elements of the orbifold homology. This also explains why in certain cases, the SCFT can appear to contribute a “fraction of a hypermultiplet” to the anomaly polynomial. Quantization of the lattice of string charges also predicts the existence of additional light states beyond those captured by such fractional divisors. This amounts to a refinement to the lattice of divisors in the resolved geometry. We illustrate these general considerations with explicit examples, focusing on the case of F-theory on an elliptic Calabi-Yau threefold with base $$ {\mathrm{\mathbb{P}}}^2/{\mathbb{Z}}_3 $$ .
Structure of cosmic ray-modified perpendicular shocks

Kinetic diffusion of cosmic rays ahead of perpendicular shocks induces charge non-neutrality, which is mostly, yet not completely, screened by the bulk plasma via polarization drift current. Hydrodynamic shear instabilities as well as the modified Buneman instability of the polarization current generate the turbulence necessary for a Fermi-type acceleration. Thus, similar to the case of parallel shocks, in perpendicular shocks the diffusing cosmic rays generate unstable plasma currents that in turn excite turbulence. This allows for a self-consistent evolution of a shock-cosmic ray system. In the kinetic regime of the modified Buneman instability, electrons may be heated in the cosmic ray precursor.
Protocols for Bandwidth Management in Third Generation Optical Networks

During the height of telecommunications boom all optical networking was seen as the next horizon, that would soon revolutionize the data communications world. Networking technology and service companies have been heavily investing in startups that promised to bring all optical, on demand and any bandwidth granularity solutions to the market in eighteen month or less. By the early 2001, there were several hundreds of companies focused on optical equipment development. including optical switches, optical cross-connects and similar, all coming with accompanying management software for the provisioning and control that would bring the final, all optical solution to all. A number of other service companies were focused on the delivery of next generation optically driven services, as exemplified by the emerging IXCs and CLECs in North America. The declared effect was to be a revolutionized networking, resulting in a complete shift to data based networking infrastructures.The rationale for all of the optical enthusiasm was the promise of significantly more data carrying bandwidth, new optically based service provider revenue generating service opportunities, and simplified network infrastructures that greatly reduced service provider Capex and Opex costs. New optical equipment should reduce or eliminate the costly electronic regeneration of optical signals, and new optical switching and mux equipment promised to ease the burden of path provisioning, path monitoring, and path restoration of optical data carrying paths.
Corporate Law Constraints on Political Spending

In 2008 and 2009, a financial panic nearly crippled the global economy and plunged the United States into the most severe economic downturn since the Great Depression, costing over eight million jobs. In June 2009, the administration of President Barack Obama announced its proposals to reform the financial system that had made this crisis possible. One of its central recommendations was the creation of the Consumer Financial Protection Agency (CFPA), a new regulator devoted to protecting ordinary people from the risks presented by financial products such as mortgages and credit cards. The CFPA was deeply unpopular with many businesses, particularly the financial institutions who created and sold the products that the Agency was supposed to protect consumers from. The fight against the CFPA was led by the U.S. Chamber of Commerce, a lobbying and advocacy organization that claims to represent the interests of over three million businesses. The Chamber spent millions of dollars on an advertising campaign attempting to demonize the Agency and helped organize the opposition under the banner “Stop the CFPA.” After the Consumer
Sufficient-completeness, ground-reducibility and their complexity

The sufficient-completeness property of equational algebraic specifications has been found useful in providing guidelines for designing abstract data type specifications as well as in proving inductive properties using the induction-less-induction method. The sufficient-completeness property is known to be undecidable in general. In an earlier paper, it was shown to be decidable for constructor-preserving, complete (canonical) term rewriting systems, even when there are relations among constructor symbols. In this paper, the complexity of the sufficient-completeness property is analyzed for different classes of term rewriting systems. A number of results about the complexity of the sufficient-completeness property for complete (canonical) term rewriting systems are proved: (i) The problem is co-NP-complete for term rewriting systems with free constructors (i.e., no relations among constructors are allowed), (ii) the problem remains co-NP-complete for term rewriting systems with unary and nullary constructors, even when there are relations among constructors, (iii) the problem is provably in “almost” exponential time for left-linear term rewriting systems with relations among constructors, and (iv) for left-linear complete constructor-preserving rewriting systems, the problem can be decided in steps exponential innlogn wheren is the size of the rewriting system. No better lower-bound for the complexity of the sufficient-completeness property for complete (canonical) term rewriting system with nonlinear left-hand sides is known. An algorithm for left-linear complete constructor-preserving rewriting systems is also discussed. Finally, the sufficient-completeness property is shown to be undecidable for non-linear complete term rewriting systems with associative functions. These complexity results also apply to the ground-reducibility property (also called inductive-reducibility) which is known to be directly related to the sufficient-completeness property.
Excess reserves, monetary policy and financial volatility

Abstract This paper examines the real and financial effects of reserves in a Dynamic Stochastic General Equilibrium (DSGE) model with monopoly banking and credit market imperfections. The framework explicitly accounts for the fact that commercial banks hold excess reserves and they incur costs in holding these assets. The model also accounts for imperfect substitutability between bank funding sources and it shows that this feature is an important channel through which reserve requirement shocks can affect real variables. Numerical experiments show that an increase in reserve requirements creates a countercyclical effect for real economic activity. The results also indicate that the combination of an augmented Taylor rule which responds to excess reserves and a countercyclical reserve requirement rule is optimal to mitigate macroeconomic and financial volatility associated with liquidity shocks.
Human rights as a topic and guide for LIS research and practice

In this global information age, accessing, disseminating, and controlling information is an increasingly important aspect of human life. Often, these interests are expressed in the language of human rights--for example, rights to expression, privacy, and intellectual property. As the discipline concerned with "facilitating the effective communication of desired information between human generator and human user" (Belkin, 1975, p. 22), library and information science (LIS) has a central role in facilitating communication about human rights and ensuring the respect for human rights in information services and systems. This paper surveys the literature at the intersection of LIS and human rights. To begin, an overview of human rights conventions and an introduction to human rights theory is provided. Then the intersections between LIS and human rights are considered. Three central areas of informational human rights--communication, privacy, and intellectual property--are discussed in detail. It is argued that communication rights in particular serve as a central linchpin in the system of human rights. Language: en
The Effect of a Geographic Lateral Bone Bruise on Knee Inflammation After Acute Anterior Cruciate Ligament Rupture

We prospectively evaluated 40 patients who had knee inflammation after isolated anterior cruciate ligament rupture with or without an associated "geographic" bone bruise/subchondral fracture of the lateral femoral condyle. All patients with acute ruptures documented by magnetic resonance imaging within 1 week of injury were evaluated for a geographic bone bruise/subchondral fracture of the lateral femoral condyle. Two groups of 20 patients each (bone bruise versus no bone bruise) were then enrolled. Variables measured at 1, 2, 3, and 4 weeks after injury included pain, range of motion, effusion, and number of days with an antalgic gait. Patients with a bone bruise had increased size and duration of effusion, increased number of days required to nonantalgic gait without external aids, increased days to achieve normal range of motion, and increased pain scores at measured time intervals. This study confirms results of previous clinical and histologic studies showing an associated articular cartilage lesion, otherwise known as bone bruise/subchondral fracture, is clinically significant. There appears to be an association between a geographic bone bruise and increased disability in patients with acute anterior cruciate ligament ruptures. Patients with a geographic bone bruise may require longer to reach normal homeostasis (range of motion, pain, neuromuscular control) before undergoing anterior cruciate ligament reconstruction.
OVERBIDDING AND HETEROGENEOUS BEHAVIOR IN CONTEST EXPERIMENTS

We provide an overview of experimental literature on contests and point out the two main phenomena observed in most contest experiments: (i) overbidding relative to the standard Nash equilibrium prediction and (ii) heterogeneous behavior of ex-ante symmetric contestants. Based on the sample of contest experiments that we review, the median overbidding rate is 72%. We provide different explanations for the overbidding phenomenon, including bounded rationality, utility of winning, other-regarding preferences, probability distortion, and the shape of the payoff function. We also provide explanations for heterogeneous behavior of contestants based on differences in preferences towards winning, inequality, risk and losses, and demographic differences. Furthermore, we suggest mechanisms that can reduce overbidding and induce more homogeneous behavior. Finally, we discuss directions for future research.
Higher usual alcohol consumption was associated with a lower 41-y mortality risk from coronary artery disease in men independent of genetic and common environmental factors: the prospective NHLBI Twin Study

Background: Evidence that alcohol consumption is inversely associated with long-term coronary artery disease (CAD) mortality independent of genetic and early life environmental factors is lacking. Objective: We evaluated whether alcohol consumption was prospectively associated with CAD mortality risk independent of familial factors. Design: In total, 843 male twins (396 pairs and 51 unpaired twins) aged 42–55 y (mean: 48 y) without baseline CAD reported beer, wine, and spirits consumption at baseline (1969–1973) and were followed up to 2010 in the prospective National Heart, Lung, and Blood Institute Twin Study. Data on usual alcohol consumption over the past year were collected. Outcome was time to event, where the primary event was death from CAD and secondary events were death from cardiovascular disease and all causes. HRs were estimated by using frailty survival models, both overall and within-pair. Results: There were 129 CAD deaths and 219 cardiovascular deaths during 41 y of follow-up. In the whole cohort, after adjustment for caloric intake and cardiovascular disease risk factors, overall HRs per 10-g increment in alcohol intake were 0.94 (95% CI: 0.89, 0.98) for CAD and 0.97 (95% CI: 0.93, 1.00) for cardiovascular mortality. The within-pair adjusted HRs for a twin with 10-g higher daily alcohol consumption than his co-twin were 0.90 (95% CI: 0.84, 0.97) for CAD and 0.95 (95% CI: 0.90, 1.00) for cardiovascular disease mortality in the cohort pooled by zygosity, which remained similar among monozygotic twins. All 3 beverage types tended to be associated with lower CAD mortality risk within-pair to a similar degree. Alcohol consumption was not associated with total mortality risk overall or within-pair. Conclusion: Higher usual alcohol consumption is associated with lower CAD mortality risk, independent of germline and early life environment and adulthood experience shared among twins, supporting a possible causal role of alcohol consumption in lowering CAD death risk. This trial was registered at clinicaltrials.gov as {"type":"clinical-trial","attrs":{"text":"NCT00005124","term_id":"NCT00005124"}}NCT00005124.
Falling-Film Absorption Around Microchannel Tube Banks

An experimental investigation of heat and mass transfer in a falling-film absorber with microchannel tube arrays was conducted. Liquid ammonia-water solution flows in a falling-film mode around an array of small diameter coolant tubes, while vapor flows upward through the tube array counter-current to the falling film. This absorber was installed in a test facility consisting of all components of a functional single-effect absorption chiller, including a desorber, rectifier, condenser, evaporator, solution heat exchanger, and refrigerant pre-cooler, to obtain realistic operating conditions at the absorber and to account for the influence of the other components in the system. Unlike studies in the literature on bench-top, single-component, single-pressure test stands, here the experiments were conducted on the absorber at vapor, solution, and coupling fluid conditions representative of space-conditioning systems in the heating and cooling modes. Absorption measurements were taken over a wide range of solution flow rates, concentrations, and coupling fluid temperatures, which simulated operation of thermally activated absorption systems at different cooling capacities and ambient conditions. These measurements are used to interpret the effects of solution and vapor flow rates, concentrations, and coupling fluid conditions on the respective heat and mass transfer coefficients.© 2011 ASME
Axion stars in the infrared limit

Following Ruffini and Bonazzola, we use a quantized boson field to describe condensates of axions forming compact objects. Without substantial modifications, the method can only be applied to axions with decay constant, f a , satisfying δ = (f a /M P )2 ≪ 1, where M P is the Planck mass. Similarly, the applicability of the Ruffini-Bonazzola method to axion stars also requires that the relative binding energy of axions satisfies $$ \varDelta =\sqrt{1-{\left({E}_a/{m}_a\right)}^2}\ll 1 $$ , where E a and m a are the energy and mass of the axion. The simultaneous expansion of the equations of motion in δ and Δ leads to a simplified set of equations, depending only on the parameter, $$ \lambda =\sqrt{\delta }/\varDelta $$ in leading order of the expansions. Keeping leading order in Δ is equivalent to the infrared limit, in which only relevant and marginal terms contribute to the equations of motion. The number of axions in the star is uniquely determined by λ. Numerical solutions are found in a wide range of λ. At small λ the mass and radius of the axion star rise linearly with λ. While at larger λ the radius of the star continues to rise, the mass of the star, M , attains a maximum at λmax ≃ 0.58. All stars are unstable for λ > λmax. We discuss the relationship of our results to current observational constraints on dark matter and the phenomenology of Fast Radio Bursts.
Pattern selection in rotating convection with experimental boundary conditions.

present the results of weakly nonlinear calculations that enable us to compute accurately both the critical rotation rate beyond which rolls are Kuppers-Lortz unstable as well as the angle with which the instability sets in. These quantities are a sensitive function of the Prandtl number, and here the results differ considerably from those with more idealized boundary conditions. The remainder of the paper is concerned with weakly nonlinear oscillatory convection. The calculations are restricted to two spatial dimensions so that the nonlinear problem concerns only traveling and standing waves. We determine the relative stability between these two patterns and show that either may be stable, depending on the system parameters. In this discussion we are careful to consider the impact of distant sidewalls in preventing the appearance of the mean flows that are associated with traveling patterns in unbounded systems. As in the Kiippers-Lortz calculation we consider stability only with respect to perturbations of the same wave number as the basic pattern. Although this procedure excludes a large class of potentially important perturbations, prior experience suggests that the selected perturbations are the most dangerous. In addition this restriction enables us to rely on results obtained from equivariant bifurcation theory. This technique [6] allows us to classify the possible weakly nonlinear and spatially periodic states and establish their relative stability. In addition it identifies precisely the computations that have to be carried out on the partial diiferential equations in order to discriminate among the possible scenarios. The paper is organized as follows. In the following section we summarize the relevant bifurcation theory results. In Sec. III we formulate the hydrodynamical equations and describe the technique we use to solve them. In Sec. IV we solve the linear stability problem for the conduction solution and identify regions in parameter space where oscillatory and steady-state convection takes place. In Sec. V we restrict the region of stable smallamplitude rolls by computing the location of the onset of
Distributed scheduling and resource allocation for cognitive OFDMA radios

Scheduling spectrum access and allocating power and rate resources are tasks affecting critically the performance of wireless cognitive radio (CR) networks. The present contribution develops a primal-dual optimization framework to schedule any-to-any CR communications based on orthogonal frequency division multiple access and allocate power so as to maximize the weighted average sum-rate of all users. Fairness is ensured among CR communicators and possible hierarchies are respected by guaranteeing minimum rate requirements for primary users while allowing secondary users to access the spectrum opportunistically. The framework leads to an iterative channel-adaptive distributed algorithm whereby nodes rely only on local information exchanges with their neighbors to attain global optimality. Simulations confirm that the distributed online algorithm does not require knowledge of the underlying fading channel distribution and converges to the optimum almost surely from any initialization.
Transverse Structure of the Nucleon and Multiparton Interactions

Transverse structure of the nucleon as probed in the hard exclusive processes plays a critical role in understanding the structure of the underlying events in hard collisions at the LHC, and multiparton interactions. I summarize some results of our recent studies of manifestation of transverse nucleon structure in the hard collisions at the LHC, new generalized parton distributions involved in multiparton interactions, and an important role of double-parton interactions in the two pion production in pp and d-Au collisions at RHIC.
Catalytic Asymmetric Diamination of Conjugated Dienes and Triene

This paper describes a catalytic asymmetric diamination process using di-tert-butyldiaziridinone as nitrogen source with catalyst generated from Pd2(dba)3 and chiral phosphorus amidite ligand. A wide variety of conjugated dienes and triene can be effectively diaminated in good yields with high regio-, diastereo-, and enantioselectivities.
Phase-pulling and breather instability in an AC-driven damped one-dimensional sine-Gordon system

Abstract An AC-driven damped sine-Gordon system, in the nonlinear Schrodinger regime, may converge into various nontrivial space-time attractors. One of them is breather riding on top of flat profile, both locked to the driver frequency. Using collective-coordinate ansatz for this attractor, and a multiple-scale perturbation technique, we study the location and nature of its instability. Among the various characteristics, this study includes understanding the role of the breather-background coupling, the structure of the associated unstable modes, the scaling structure of the instability boundary, etc. Most strikingly we find the instability mechanism and the above features to be strongly sensitive to the asymptotic phase-difference between the spatially localized breather and the spatially extended uniform background. We call this phenomenon “phase-pulling”.
Infrared photochemistry of bis(trifluoromethyl) peroxide

Bis(trifluoromethyl) peroxide is readily dissociated by multiple infrared photon excitation at CO2 laser wavelengths. The primary dissociation product is CF3O; approximately 85% of the nascent radicals are further dissociated in the laser field to form CF2O and F. The F atoms then react with the remaining CF3O to produce CF3OF. The formation of CF3OF is strongly inhibited by addition of HI, which reacts preferentially with the F atoms.
Oxidized Silicon-On-Insulator (OxSOI) from bulk silicon: a new photonic platform

We demonstrate a bulk silicon alternative to SOI, using Si 3 N 4 masking and oxidation techniques. We show waveguide losses of 2.92 dB/cm with a process compatible with the front-end of a typical CMOS fabrication line.
Self-consistent random-phase approximation for interacting electrons in quantum wells and intersubband absorption

For electrons with Coulomb interaction confined in a quantum well, we have developed an approach based on the Kadanoff-Baym-Keldysh technique to calculate equilibrium Green's functions. This approach is based on iterative numerical computation of the retarded self-energy in the self-consistent random-phase approximation. For two subbands, at zero temperature, we have computed spectral functions, electron distributions, quasiparticle spectra, and the current-current correlation function that determines the intersubband absorption coefficient. Our computations of the optical absorption take into account the depolarization shift and vertex corrections. Apart from direct applications of this theory to the physics of semiconductor quantum well devices, the Green's functions obtained may also serve as self-consistent initial conditions for quantum kinetics problems in quantum wells.
Graph-Based Algorithm for Dynamic Airspace Configuration

In this paper, a new algorithm for dynamic airspace configuration is developed based on graph theory. A graph model is first constructed that accurately represents the air-route structure and air traffic in the National Airspace System. The airspace configuration problem is then formulated as a graph-partitioning problem to balance the subgraph (sector) workload while satisfying the capacity constraint, which is efficiently solved by a spectral clustering method. Since the original spectral clustering method shows some undesirable properties, such as disconnected subgraphs and unbalanced partitions, an algorithm is proposed to refine the partitions. Lastly, using the partitioned graph as an input, a novel airspace sectorization algorithm is developed, based on the graph search method. The new sectors computed by the sectorization algorithm have smooth boundaries and good geometrical shapes, which satisfy the minimum distance requirement (i.e., the sector boundaries are at least a minimum distance away from the airports, waypoints, and main air routes). The performance of the proposed dynamic airspace configuration algorithm is validated through various air-traffic scenarios with real air-traffic data.
Stabilization by Hydrogen. Synthetic and Structural Studies of the Zintl Phase Ba5Ga6H2

Synthesis of the phase formerly reported as Ba5Ga6 succeeds only in the presence of hydrogen. The heavy atom structure of Ba5Ga6H2 has been redetermined by single-crystal X-ray diffraction (trigonal P3c1, Z = 2, a = 7.7698(2) A, c = 14.3902(7) A), and the hydrogen positions have been elucidated by time-of-flight neutron powder diffraction. The unit cell contains isolated slightly distorted octahedra Ga68- with barium cations over all edges. Hydride is bound in two types of barium tetrahedra [d(Ba−H) = 2.61−2.62 A]. The stoichiometry is appropriate for a Zintl phase: (Ba2+)5Ga68-(H-)2.
HST to HST10X: a second revolution in space science

The Hubble Space Telescope is arguably one of the most important and successful scientific endeavors undertaken in the twentieth century. Hubble, a modest-sized 2.4-m telescope, outperforms much larger terrestrial telescopes because it is diffraction limited, and because the sky seen from orbit is darker than the terrestrial night sky. If we increase the diameter of Hubble to 8.4-m, a diameter comparable to Keck and the VLT, the increase in capability will be comparable to that which was first achieved by Hubble's launch and subsequent repair. HST10X will allow a fast track solution of outstanding problems in astronomy. Perhaps foremost among these is the detection of earth-like planets orbiting nearby stars. HST10X can detect earth-like planets around stars at distances up to 10 parsecs. Furthermore, HST10X will enable spectroscopic examination of earth-like planets to search for atmospheric oxygen, a certain sign of life.
Neutral sulfur nucleophiles: synthesis of thioethers and thioesters by substitution reactions of N-heterocyclic carbene boryl sulfides and thioamides.

Newly discovered boryl sulfides and N-borylthioamides are shown to serve as neutral sources of sulfur nucleophiles in substitutions reactions. For example, heating of diMe-Imd-BH(SPh)2 with benzyl bromides, primary bromides, or acid chlorides provides the corresponding thioethers or thioesters in high yields. Likewise, N-phenyltetrazole thioethers/esters are made from a readily available N-borylthionotetrazole. The formation of the boryl sulfide and its onward nucleophilic substitution can be telescoped down to a one-pot reaction whose components are an NHC–borane (NHC-BH3), a disulfide, and an electrophile.
The diameter of long-range percolation clusters on finite cycles

Bounds for the diameter and expansion of the graphs created by long-range percolation on the cycle ℤ/Nℤ are given. © 2001 John Wiley & Sons, Inc. Random Struct. Alg., 19: 102–111, 2001
Shaky Roads and Trembling Exports: Assessing the Trade Effects of Domestic Infrastructure Using a Natural Experiment

Abstract Our knowledge of the trade effects of domestic infrastructure is very limited. The reason is twofold. First, data needed to examine these effects are not readily available. Second, identifying such effects requires properly addressing potential endogeneity problems affecting the relationship between internal infrastructure and trade. In this paper, we overcome these limitations by combining firm-level export data with detailed geo-referenced information on Chile and by exploiting the earthquake that took place in this country in 2010 as an exogenous source of variation in available infrastructure and thereby in transport costs. We find that diminished transportation infrastructure had a significant negative impact on firms' exports.
Distributed algorithms for covering, packing and maximum weighted matching

This paper gives poly-logarithmic-round, distributed δ-approximation algorithms for covering problems with submodular cost and monotone covering constraints (Submodular-cost Covering). The approximation ratio δ is the maximum number of variables in any constraint. Special cases include Covering Mixed Integer Linear Programs (CMIP), and Weighted Vertex Cover (with δ = 2). Via duality, the paper also gives poly-logarithmic-round, distributed δ-approximation algorithms for Fractional Packing linear programs (where δ is the maximum number of constraints in which any variable occurs), and for Max Weighted c-Matching in hypergraphs (where δ is the maximum size of any of the hyperedges; for graphs δ = 2). The paper also gives parallel (RNC) 2-approximation algorithms for CMIP with two variables per constraint and Weighted Vertex Cover. The algorithms are randomized. All of the approximation ratios exactly match those of comparable centralized algorithms.
Fast meridional transport in the lower thermosphere by planetary-scale waves

Abstract Observations showed that the main engine water exhaust plumes from space shuttles released at ∼110 km altitude from Florida could be transported over thousands of kilometers northward or southward, reaching the Arctic after a day or so, and in one case Antarctica after three days ( Stevens et al., 2003 , Stevens et al., 2005 ). In this work, we study the meridional transport associated with the quasi-two-day wave (QTDW) and migrating tides. Diagnostic calculations are performed to trace the particle trajectories using winds from the Thermosphere–Ionosphere–Mesosphere-Electrodynamics General Circulation Model (TIME-GCM) simulations for January, when the amplitude of the QTDW usually peaks. The calculations demonstrate that the mean meridional circulation, a QTDW or a migrating tide cannot individually sustain planetary-scale meridional transport for one to three days, but the combined effects of a QTDW and a tide can. In particular, when the QTDW and the tides are scaled according to the observed amplitudes, particles released at ∼110 km and appropriate longitudes/local times can undergo transport fast enough to reach Antarctica within three days as observed. The magnitude and direction of the transport depend on the amplitudes and phases of the tides and the QTDW. These simulations thus suggest that the observed rapid planetary-scale meridional transport of the shuttle main engine plume can be driven by planetary waves and tides.
Permanent and transitory income in models of housing demand

Abstract Permanent income has for some time been recognized as the appropriate income variable for models of housing demand. This paper examines a recently developed model wherein permanent and transitory income are considered to be the fitted and residual components, respectively, of a regression of actual income on several household characteristics. An important caveat for these models is pointed out. One logical remedial strategy is shown to result in underidentification for the coefficient on permanent income. However, the technique uncovers a tangential result which summarizes why an alternative class of models can be expected to underestimate income elasticities.
Fluctuation-Driven 1st-Order Isotropic-to-Tetrahedratic Phase Transition

Motivated in part by recent experiments on liquid crystals with bent-core molecules, which are observed to display a spontaneous chiral symmetry breaking, we introduce a field theory of a 3rd-rank tensor order parameter Tijk to describe the isotropic-to-tetrahedratic phase transition that we predict to take place in these materials. We study the critical properties of the corresponding phase transition and find that this transition, continuous at the mean-field level, is generically driven 1st-order by thermal fluctuations.
Fiber-optic Cherenkov radiation in the few-cycle regime

We demonstrate (both theoretically and experimentally) that fiber-optic Cherenkov radiation in the few-cycle regime exhibits three unique features absent when pumped with long pulses: continuum generation, high conversion-efficiency (up to 40%), and broad bandwidth (70-nm).
Wall Crossing of BPS States on the Conifold from Seiberg Duality and Pyramid Partitions

In this paper we study the relation between pyramid partitions with a general empty room configuration (ERC) and the BPS states of D-branes on the resolved conifold. We find that the generating function for pyramid partitions with a length n ERC is exactly the same as the D6/D2/D0 BPS partition function on the resolved conifold in particular Kahler chambers. We define a new type of pyramid partition with a finite ERC that counts the BPS degeneracies in certain other chambers.
Probing the surface-to-bulk transition: A closed-form constant-scaling algorithm for computing subsurface Green functions

A closed-form algorithm for computing subsurface Green functions—the blocks of a material’s Green function between the surface and the bulk—is presented, where we assume the system satisfies a common principal-layer approximation. By exploiting the block tridiagonal and nearly block Toeplitz structure of the Hamiltonian and overlap matrices, this method scales independently of the system size (constant scaling), allowing studies of large systems. As a proof-of-concept example, we investigate the decay of surface effects in an armchair graphene nanoribbon, demonstrating the persistence of surface effects hundreds of atomic layers (∼0.5 μm) away from a surface. We finally compare the surface-to-bulk transitions of finite and semi-infinite systems, finding that finite systems exhibit amplified surface effects.
Solitons on singularities

We describe solitons that live on the world-volumes of D5 branes wrapped on deformed An singularities fibered over C(x). We show that monopoles are D3 branes wrapped on an A1 singularity and stretched along C(x). F and D-term strings are D3 branes wrapped on a node of an A2 singularity that is deformed and resolved respectively. Domain walls are D5 branes wrapped on a deformed A3 singularity and stretched along C(x).
Quasi-experimental analysis of the impact of exchange rate regime selection on crisis recovery: evidence from the Asian Financial Crisis

Research typically treats exchange rate regime selection as exogenous. Using the Asian Financial Crisis as a case study, we show that countries that peg in 1996 and countries that float in 1996 are, on average, different from each other on variables that affect the outcomes of interest. After accounting for endogenous exchange rate regime selection using propensity score matching, we find that a country’s exchange rate regime choice in 1996 had no significant impact on the size of the shock to real income levels, but reduced subsequent income growth and weakly increased inflation.
Multirate rearrangeable clos networks and a generalized edge coloring problem on bipartite graphs

Chung and Ross (SIAM J. Comput., 20, 1991) conjectured that the minimum number m(n, r) of middle-state switches for the symmetric 3-stage Clos network C(n, m(n, r), r) to be rearrangeable in the multirate enviroment is at most 2n -- 1. This problem is equivalent to a generalized version of the biparite graph edge coloring problem. The best bounds known so far on the function m(n, r) is 11n/9 ≤ m(n, r) ≤ 41n/16 + O(1), for n, r ≥ 2, derived by Du-Gao-Hwang-Kim (SIAM J. Comput., 28, 1999). In this paper, we make several contributions. Firstly, we give evidence to show that even a stronger result might hold. In particular, we give a coloring algorithm to show that m(n, r) ≤ [(r + 1)n/2], which implies m(n, 2) ≤ [3n/2] - stronger than the conjectured value of 2n -- 1. Secondly, we derive that m(2, r) = 3 by an elegant argument. Lastly, we improve both the best upper and lower bounds given above: [5n/4] ≤ m(n, r) ≤ 2n -- 1 + [(r -- 1)/2], where the upper bound is an improvement over 41n/16 when r is relatively small compared to n. We also conjecture that m(n, r) ≤ [2n (1 -- 1/2(r)].
Suppression of Insulin Secretion by Protein Deprivation in Obesity

Hyperinsulinemia, decreased sensitivity of peripheral tissues to both exogenous and endogenous insulin and abnormalities of glucose tolerance are frequent findings in obesity (1). These abnormalities are frequently reversed by dietary deprivation and weight reduction (2) and induced in normal subjects made obese by overfeeding. The role played by specific nutrients in the hyperinsulinemia of obese people has not been clearly defined. Studies by Grey and Kipnis (3) suggest that diets high in carbohydrate are associated with hyperinsulinemia while isocaloric diets low in carbohydrate decrease circulating insulin levels. In contrast to these observations, Brunzell, et al, (4) reported that high carbohydrate diets given to normal subjects or mildly diabetic patients decrease basal and glucose stimulated insulin levels and improve glucose tolerance.
Magnetic Structures of Solar Active Regions, Full-Halo Coronal Mass Ejections, and Geomagnetic Storms

We have analyzed three active regions to investigate the relationship between magnetic configurations of active regions and geomagnetic storms. Each active region was associated with multiple full-halo coronal mass ejections (CMEs). This study demonstrates that, although full-halo CMEs may originate from the same active region, it is not necessary for them to have similar geoeffectiveness, depending on the magnetic configurations actually involved in the corresponding flare activities. This implies that (1) the flares, CMEs, and geomagnetic storms are closely related magnetically, as already suggested by many others, and (2) the occurrence of solar active region-related geomagnetic storms may be determined by the magnetic fields that are involved in the corresponding solar flares. These associations suggest ways to improve geomagnetic storm prediction.
Optimizing Consumer Credit Markets and Bankruptcy Policy

This Article explores the relationship between consumer credit markets and bankruptcy policy. In general, I argue that the causative relationships running between borrowing and bankruptcy compel a new strategy for policing the conduct of lenders and borrowers in modern consumer credit markets. The strategy must be sensitive to the role of the credit card in lending markets and must recognize that both issuers and cardholders are well placed to respond to the increased levels of spending and indebtedness. In the latter parts of the Article, I recommend mandatory minimum payment requirements, a tax on distressed credit card debt, and the subordination of payments to credit card lenders in bankruptcy. I also argue that many aspects of the American bankruptcy system, as recently reformed, are overly protective of credit card issuers.
Liquid Argon as an Electron/Photon Detector in the Energy Range of 50 Mev to 2 Gev: A Monte Carlo Investigation

Using Monte Carlo techniques, the characteristics of a proposed electron/photon detector based on the total absorption of electromagnetic showers in liquid argon have been investigated. The energy range studied was 50 MeV to 2 GeV. Results are presented on the energy and angular resolution predicted for the device, along with detailed predictions of the transverse and longitudinal shower distributions. Comparisons are made with other photon detectors, and possible applications are discussed.
Software design for distributed sensing and computing tasks

In this paper we illustrate the benefits of a strongly typed software design framework, explore the difficulties in applying such a system in a distributed sensing setting, and describe the extended type system we have created and fielded in multi-robot sensing experiments. While the built-in type systems of modern object-oriented languages provide much of the functionality we desire, there is a level of synchronization required by both static and dynamic linking that limits the applicability of such a system to a scalable distributed sensing and computing platform. We show how the limitations of these robust strong type systems can be overcome, allowing one to bring their power to bear on distributed sensing. By adhering to a formal, well-supported type system, our framework offers a scalable approach to dynamic resource discovery and exploitation. A natural consequence of the platform’s design is a higher level design system for building multi-agent programs that itself enforces type safety when pairing data sources and sinks, both when the distributed task is being launched and as the task dynamically reconfigures itself to exploit new resources.
Number variance of random zeros on complex manifolds

We show that the variance of the number of simultaneous zeros of m i.i.d. Gaussian random polynomials of degree N in an open set \(U \subset {\mathbb{C}}^m\) with smooth boundary is asymptotic to \(N^{{m-1}/2} \nu_{mm} {\rm Vol}(\partial U)\), where \(\nu_{mm}\) is a universal constant depending only on the dimension m. We also give formulas for the variance of the volume of the set of simultaneous zeros in U of k < m random degree-N polynomials on \({\mathbb{C}}^{m}\). Our results hold more generally for the simultaneous zeros of random holomorphic sections of the N-th power of any positive line bundle over any m-dimensional compact Kahler manifold.
Cool-flame extinction during n-alkane droplet combustion in microgravity

Abstract Recent droplet-combustion experiments onboard the International Space Station (ISS) have revealed that large n-alkane droplets, following radiative extinction of the visible flame, can continue to burn quasi-steadily in a low-temperature regime, characterized by negative-temperature-coefficient (NTC) chemistry. In this study we report experimental observations of n-heptane, n-octane, and n-decane droplets of varying initial size burning in oxygen/nitrogen, oxygen/nitrogen/carbon dioxide, and oxygen/nitrogen/helium environments at pressures from 0.5 to 1.0 atm, with oxygen concentrations from 14% to 25% by volume. These large n-alkane droplets exhibited radiative extinction of the hot flame, followed by quasi-steady low-temperature burning, which terminated with diffusive extinction accompanied by the formation of a vapor cloud, while small droplets did not exhibit radiative extinction but instead burned to completion or disruptively extinguished. Results for droplet burning rates in both the hot-flame and cool-flame regimes, as well as droplet extinction diameters at the end of each stage, are presented. The cool-flame extinction diameters for all three n-alkanes are shown to follow a similar trend as functions of the oxygen concentration, predicted here from a simplified theoretical model that is based on the reaction-rate parameters for the oxygen molecule addition to the alkyl radical and for ketohydroperoxide decomposition.
Quantum cosmology aspects of D3 branes and tachyon dynamics

We investigate aspects of quantum cosmology in relation to string cosmology systems that are described in terms of the Dirac-Born-Infeld action. Using the Silverstein-Tong model, we analyze the Wheeler-DeWitt equation for the rolling scalar and gravity as well for R × S3 universe, by obtaining the wave functions for all dynamical degrees of freedom of the system. We show, that in some cases one can construct a time dependent version of the Wheeler-DeWitt (WDW) equation for the moduli field . We also explore in detail the minisuperspace description of the rolling tachyon when non-minimal gravity tachyon couplings are inserted into the tachyon action.