cssi/SciSciGPT-SciSciNet huggingface dataset:
Topologically Enhanced Slicing of MLS Surfaces

Growing use of massive scan data in various engineering applications has necessitated research on point-set surfaces. A point-set surface is a continuous surface defined directly with a set of discrete points. This paper presents a new approach that extends our earlier work on slicing point-set surfaces into planar contours for rapid prototyping usage. This extended approach can decompose a point-set surface into slices with guaranteed topology. Such topological guarantee stems from the use of Morse theory based topological analysis of the slicing operation. The Morse function for slicing is a height function restricted to the point-set surface, an implicitly defined moving least-squares (MLS) surface. We introduce a Lagrangian multiplier formulation for critical point identification from the restricted surface. Integral lines are constructed to form Morse-Smale complex and the enhanced Reeb graph. This graph is then used to provide seed points for forming slicing contours, with the guarantee that the sliced model has the same topology as the input point-set surface. The extension of this approach to degenerate functions on point-set surface is also discussed.
Opportunities and Challenges in Materials Development for Thin Film Solid Oxide Fuel Cells

Solid oxide fuel cells (SOFCs) are currently the focus of intense investigation given their high chemical-to-electrical energy conversion efficiency and low carbon footprint. In this review, the development of thin film SOFCs, sometimes described as ‘micro-SOFCs', is highlighted and analysed. Opportunities for reduced temperature operation and portable power generation arise from the decreased thickness of the solid electrolyte, as well at the metastable phases and nanoscale-dependent effects that are a consequence of the reduced temperature of fabrication. Challenges such as enhanced cation diffusion along grain boundaries are; however, also observed, potentially impacting the long-term stability of these devices. Recent progress achieved in understanding these and other challenges are reviewed and directions for future work identified.
On Groups with Cayley Graph Isomorphic to a Cube

We say that a group G is a cube group if it is generated by a set S of involutions such that the corresponding Cayley graph Cay(G, S) is isomorphic to a cube. Equivalently, G is a cube group if it acts on a cube such that the action is simply-transitive on the vertices and the edge stabilizers are all nontrivial. The action on the cube extends to an orthogonal linear action, which we call the geometric representation. We prove a combinatorial decomposition for cube groups into products of 2-element subgroups, and show that the geometric representation is always reducible.
Weakly warped extra dimensions and SN1987A

The neutrino pulse from SN1987A provides one of the most rigourous constraints on models of extra dimensions. Previously, calculations have been done to bound the size of these extra dimensions in the case when the metric was factorizable. Here we consider the case of 2 `weakly warped' extra dimensions. We find that even though weak warping seems only to affect the zero mode this can have a measurable effect on the supernovae bounds. In any braneworld model such warping is necessarily present and as such should be taken into account in supernovae bounds and in searches for corrections to newtonian gravity.
Scaling and linear response in the GOY turbulence model

The GOY model is a model for turbulence in which two conserved quantities cascade up and down a linear array of shells. When the viscosity parameter, small nu, Greek, is small the model has a qualitative behavior which is similar to the Kolmogorov theories of turbulence. Here a static solution to the model is examined, and a linear stability analysis is performed to obtain response eigenvalues and eigenfunctions. Both the static behavior and the linear response show an inertial range with a relatively simple scaling structure. Our main results are: (i) The response frequencies cover a wide range of scales, with ratios which can be understood in terms of the frequency scaling properties of the model. (ii) Even small viscosities play a crucial role in determining the model's eigenvalue spectrum. (iii) As a parameter within the model is varied, it shows a "phase transition" in which there is an abrupt change in many eigenvalues from stable to unstable values. (iv) The abrupt change is determined by the model's conservation laws and symmetries.
Accrued Earnings and Growth: Implications for Future Profitability and Market Mispricing

Prior research reveals that the accrual component of profitability is less persistent than the cash flow component, and that investors fail to fully appreciate their differing implications for future profitability (Sloan 1996). However, accruals are a component of growth in net operating assets as well as a component of profitability. Just as we can disaggregate profitability into accruals and cash flows from operations, we can disaggregate growth in net operating assets into accruals and growth in long‐term net operating assets. We find that, after controlling for current profitability, both components of growth in net operating assets—accruals and growth in long‐term net operating assets—have equivalent negative associations with one‐year‐ahead return on assets. This result is consistent with conservative accounting and diminishing marginal returns on investments. We also find that, after controlling for current profitability, the market appears to equivalently overvalue accruals and growth in long‐term...
DU-6859a, a new fluoroquinolone agent comparative in vitro activity against enteric pathogens and multiresistant outpatient Escherichia coli

The activity of DU-6859a, a new fluoroquinolone antimicrobial agent, was compared with that of ciprofloxacin by agar dilution susceptibility testing against enteric pathogens and multiresistant Escherichia coli. The results indicate that DU-6859a inhibits most of these organisms at concentrations similar to those of ciprofloxacin. DU-6859a showed increased activity compared to ciprofloxacin against Campylobacter species isolates.
Financial shocks and worry about the future

Using data from the Health and Retirement Study and the Survey of Consumer Finances, we show that households that experience adverse financial shocks worry more about the adequacy of their financial resources in retirement, even after controlling for the effects of these shocks on overall wealth. We find supporting evidence that suggests that at least part of the increased worry about retirement is due to general pessimism rather than changes in an individual’s own circumstances. Specifically, experiencing idiosyncratic financial shocks is also associated with greater pessimism about the general future of the economy.
Word maps have large image

An elementw in the free group onr letters defines a mapf w,G:Gv→G for each groupG. In this note, we show that wheneverw≠1 andG is a semisimple algebraic group,f w,G is dominant. As an application, we show that for fixedw and Γ i a sequence of pairwise non-isomorphic finite simple groups, $$\mathop {lim}\limits_{i \to \infty } \frac{{log\left| {\Gamma _j } \right|}}{{log\left| {f_w ,\Gamma _j (\Gamma _j^r )} \right|}} = 1$$ .
Reduction and Emergence in Bose-Einstein Condensates

A closer look at some proposed Gedanken-experiments on BECs promises to shed light on several aspects of reduction and emergence in physics. These include the relations between classical descriptions and different quantum treatments of macroscopic systems, and the emergence of new properties and even new objects as a result of spontaneous symmetry breaking.
Scarring and Mortality Selection Among Civil War POWs: A Long-Term Mortality, Morbidity, and Socioeconomic Follow-Up

Debilitating events could leave either more frail or more robust survivors, depending on the extent of scarring and mortality selection. The majority of empirical analyses find more frail survivors. I find heterogeneous effects. Among severely stressed former Union Army prisoners of war (POWs), the effect that dominates 35 years after the end of the Civil War depends on age at imprisonment. Among survivors to 1900, those younger than 30 at imprisonment faced higher old-age mortality and morbidity and worse socioeconomic outcomes than non-POW and other POW controls, whereas those older than 30 at imprisonment faced a lower older-age death risk than the controls.
Magnetic critical temperature gap in Gd-Y alloys

Abstract In a search for Lifshitz points a very interesting and complex region in the magnetic phase diagram of Gd-Y alloys near 30 at% Y was found. An apparent jump (gap) in the highest ordering temperature and perplexing magnetic behavior was observed.
Rydberg levels of lithium.

The electrostatic fine structure for singly excited lithium is accurately calculated using an effective potential method that has proven to be very useful for helium. Relevant properties of the two-electron ${\mathrm{Li}}^{+}$ ionic core with finite nuclear mass are determined from variational wave functions. From these, non- relativistic level shifts are obtained analytically, and the leading relativistic correction is applied. A comparison with recent experimental results is made.
Hydrogen bonding in tungsten (VI) salicylate free acids

Abstract Hydrogen-bonded free acid dimers of the formula [W(X)Cl3(Hsal–R)]2 (where X=O (1), NC6H3-2,6-Me2 (2), Ph2C2 and Hsal–R=substituted salicylate monoanion) are prepared through reactions between W(X)Cl4 precursors and functionalized salicylic acids (H2sal–R). Download : Download full-size image The free acids are stable at ambient temperature and exist as dimers in solution, although the structure of the dimer is not known. Spectroscopic studies show that the electronic characteristics of the π-donor ligands directly affect the electronic environments of the carboxylate functionality. This influence is observed in weaker binding constants of diethyl ether (KX) as the X ligand becomes more strongly π donating: O⩾NC6H3–2,6-Me2>Ph2C2. In other words, the oxo and aryl imido species are more acidic than the diphenylacetylene compounds in the Bronsted sense owing to the higher Lewis acidity of their tungsten centers. Salicylate adducts of the type W(X)Cl3(Hsal–R)⋯OR2′ (X=O (3), NC6H3–2,6-Me2 (4)) and W(X)Cl3(Hsal–R)⋯NEt3 (X=O (5), NC6H3–2,6-Me2 (6)) have been isolated and characterized. A comparison of two structures, W(NC6H3–2,6-Me2)Cl3(Hsal–3-Me⋯L) where L=OEt2 (4c) and NEt3 (6c), shows that 6c has more charge localization on both the carboxylate group and tungsten center than 4c. The charge separation in amine adducts (i.e. salts) contributes to association of these salts with the free acid (i.e. W(X)Cl3(Hsal–R⋯L)⋯[W(X)Cl3(Hsal–R)]). The strong hydrogen bonding exhibited by the free acids leads to the formation of supramolecular complexes organized around poly(ether) templates, including dimethoxyethane (in 3e) and 18-crown-6.
Trimethylsilylcyanation of aldehydes and ketones catalyzed by diorganotin dichlorides

Abstract Dibutyltin dichloride and diphenyltin dichloride functioned as effective catalysts for the trimethylsilylcyanation of aldehydes and ketones. Isolated yields ranged from 71% to 97%.
Still-image compression using CVQ and wavelet transform

Wavelet transform which provides a multiresolution representation of images has been widely used in image and video compression. An investigation of wavelet decomposition reveals the cross-correlation among subimages at different resolutions. To exploit this cross-correlation, a new scheme using classified vector quantization to encode wavelet coefficients is proposed in this paper. The original image is first decomposed into a hierarchy of three layers containing ten subimages by discrete wavelet transform. The lowest resolution low frequency subimage is scalar quantized since it contains most of the energy of the wavelet coefficients. All high frequency subimages are vector quantized to utilize the cross-correlation among different resolutions. Vectors are constructed by combining the corresponding coefficients of the high frequency subimages of the same orientation at different resolutions. Classified vector quantization is used to reduce edge distortion and computational complexity. Computer simulations are carried out to evaluate the performance of the proposed method.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Exponential Dowling structures

The notion of exponential Dowling structures is introduced, generalizing Stanley's original theory of exponential structures. Enumerative theory is developed to determine the Mobius function of exponential Dowling structures, including a restriction of these structures to elements whose types satisfy a semigroup condition. Stanley's study of permutations associated with exponential structures leads to a similar vein of study for exponential Dowling structures. In particular, for the extended r-divisible partition lattice we show that the Mobius function is, up to a sign, the number of permutations in the symmetric group on rn+k elements having descent set {r,2r,...,nr}. Using Wachs' original EL-labeling of the r-divisible partition lattice, the extended r-divisible partition lattice is shown to be EL-shellable.
ON THE SELECTION OF PRIMARY PATHS FOR A COMMUNICATION-NETWORK

Abstract This paper deals with a non-bifurcated flow assignment problem in communication networks in which communication paths are limited to a set of pre-selected paths for each node pair. This problem is formulated as a mixed 0–1 linear model with multiple-choice constraints. A heuristic algorithm is presented, which takes a straightforward iterative approach, conceptually similar to that of the Simplex method, for finding the characterized local optimal solution. Several subprocedures which exploit the special structure of the model are included to make the algorithm computationally efficient. The relaxed linear programming model is used for the analysis of the algorithm, and its solution is found to be a tight lower bound. Applications of the algorithm to problems with other performance criteria are also suggested. Computational experience obtained thus far indicates that the algorithm almost always guarantees a quick convergence to a good suboptimal solution.
Convenient Oxidation of Phenothiazine Salts to Their Sulfoxides with Aqueous Nitrous Acid

A Simple method is reported for the preparation of gram quantities of phenothiazine sulfoxides by aqueous nitrous acid oxidation of phenothiazines at room temperature. The chiral levomepromazine gave rise to diastereoisomeric products analogous to those reported for thioridazine sulfoxidation.
Intraday price‐reversal patterns in the currency futures market: The impact of the introduction of GLOBEX and the euro

This article assesses the intraday price-reversal patterns of seven major currency futures contracts traded on the Chicago Mercantile Exchange over 1988–2003 after 1-day returns and opening gaps. Significant intraday price-reversal patterns are observed in five of the seven currency futures contracts, following large price changes. Additional tests are conducted in three subperiods (1988–1992, 1993–1998, and 1999–2003) to examine the impact of the introduction of electronic trading on GLOBEX in 1992 (to assess how a near 24-hour trading session might impact the next-day opening and closing futures prices) and the introduction of the euro in 1999 (to assess its impact on price predictability in other futures markets). It is found that the introduction of the GLOBEX in 1992 significantly reduced pricing errors in currency futures in the second subperiod, making the currency futures markets fairly efficient. However, the introduction of the new currency, the euro, and the disappearance of several European currencies in 1999, resulted in significant price patterns (mostly reversals and some persistence) in most of the currency futures, indicating inefficiencies in the third subperiod. © 2006 Wiley Periodicals, Inc. Jrl Fut Mark 26:1089–1130, 2006
Synchronization and redundancy: Implications for robustness of neural learning and decision making

Learning and decision making in the brain are key processes critical to survival, and yet are processes implemented by nonideal biological building blocks that can impose significant error. We explore quantitatively how the brain might cope with this inherent source of error by taking advantage of two ubiquitous mechanisms, redundancy and synchronization. In particular we consider a neural process whose goal is to learn a decision function by implementing a nonlinear gradient dynamics. The dynamics, however, are assumed to be corrupted by perturbations modeling the error, which might be incurred due to limitations of the biology, intrinsic neuronal noise, and imperfect measurements. We show that error, and the associated uncertainty surrounding a learned solution, can be controlled in large part by trading off synchronization strength among multiple redundant neural systems against the noise amplitude. The impact of the coupling between such redundant systems is quantified by the spectrum of the network Laplacian, and we discuss the role of network topology in synchronization and in reducing the effect of noise. We discuss range of situations in which the mechanisms we model arise in brain science and draw attention to experimental evidence suggesting that cortical circuits capable of implementing the computations of interest here can be found on several scales. Finally, simulations comparing theoretical bounds to the relevant empirical quantities show that the theoretical estimates we derive can be tight.
Economics and ecology: a comparison of experimental methodologies and philosophies

Abstract Views of the proper role of experiments in (environmental) economics and ecology have developed quite differently. Economics has devoted the majority of effort to abstract theory, with experimentation coming in a distant second. Kagel quotes a colleague who illustrates a common perception among economists: “I am a ‘true believer’ in microeconomic theory, and as a result I am perfectly willing to accept mathematical proofs without experimental evidence”. In contrast, ecology has focused on observation-based experiments as the primary mechanism of research, almost separate from the development of abstract theoretical ecology. Kareiva notes that “sad truth is that ecological theory exists largely in a world of its own, unnoticed by mainstream ecology”. We explore why this divergence has developed and persisted. The main reason is that economists and ecologists differ in their assumptions regarding the objective function of a model. Economists generally assume the objective function is well-defined, ecologists view the function as unknown. We higlight recent research in environmental economics to illustrate the economist's approach to experimentation.
Kinetic resolution of hydroperoxides with enantiopure phosphines: preparation of enantioenriched tertiary hydroperoxides.

An efficient reductive kinetic resolution strategy capable of accessing optically active tertiary hydroperoxides is reported. Readily accessible tertiary hydroperoxides are resolved with commercially available (R)- or (S)-xylyl-PHANEPHOS with selectivity factors as large as 37. The resulting bis(phosphine oxide) can be recycled in high yields. The isolated mono(phosphine oxide) intermediate resolved hydroperoxides with the same selectivity as the parent bisphosphine.
The Economics of Click Fraud

Click fraud is a substantial threat in the cyberworld. Here, the author examines the contexts, mechanisms, and processes associated with the click-fraud industry from an economics viewpoint. The nature of electronic channels, characterized by asymmetric hypermediation, provides a fertile ground for such fraud.
Destruction of the Galactic Globular Cluster System

We investigate the dynamical evolution of the Galactic globular cluster system in considerably greater detail than has been done hitherto, finding that destruction rates are significantly larger than given by previous estimates. The general scheme (but not the detailed implementation) follows Aguilar, Hut, & Ostriker. For the evolution of individual clusters, we use a Fokker-Planck code including the most important physical processes governing the evolution: two-body relaxation, tidal truncation of clusters, compressive gravitational shocks while clusters pass through the Galactic disk, and tidal shocks due to passage close to the bulge. Gravitational shocks are treated comprehensively, using a recent result by Kundi? & Ostriker that the ?E2 shock-induced relaxation term, driving an additional dispersion of energies, is generally more important than the usual energy shift term ?E. Various functional forms of the correction factor are adopted to allow for the adiabatic conservation of stellar actions in a presence of transient gravitational perturbation. We use a recent compilation of the globular cluster positional and structural parameters, and a collection of radial velocity measurements. Two transverse to the line-of-sight velocity components were assigned randomly according to the two kinematic models for the cluster system (following the method of Aguilar, Hut, & Ostriker): one with an isotropic peculiar velocity distribution, corresponding to the present-day cluster population, and the other with the radially preferred peculiar velocities, similar to those of the stellar halo. We use the Ostriker & Caldwell and the Bahcall, Schmidt, & Soneira models for our Galaxy. For each cluster in our sample, we calculated its orbits over a Hubble time, starting from the present observed positions and assumed velocities. Medians of the resulting set of peri- and apogalactic distances and velocities are used then as an input for the Fokker-Planck code. Evolution of the cluster is followed up to its total dissolution due to a coherent action of all of the destruction mechanisms. The rate of destruction is then obtained as a median over all the cluster sample, in accord with Aguilar, Hut, & Ostriker. We find that the total destruction rate is much larger than that given by Aguilar, Hut, & Ostriker with more than half of the present clusters (52%-58% for the Ostriker & Caldwell model, and 75%-86% for the Bahcall, Schmidt, & Soneira model) destroyed in the next Hubble time. Alternatively put, the typical time to destruction is comparable to the typical age, a result that would follow from (but is not required by) an initially power law distribution of destruction times. We discuss some implications for a past history of the globular cluster system and the initial distribution of the destruction times, raising the possibility that the current population is but a very small fraction of the initial population with the remnants of the destroyed clusters constituting presently a large fraction of the spheroid (bulge + halo) stellar population.
Perturbed Toeplitz operators and radial determinantal processes

Nous etudions une classe d’ensembles determinantaux dans le plan complexe invariants par rotation; cette classe comprend les cas des valeurs propres de matrices gaussiennes aleatoires et des zeros de certaines familles de polynomes aleatoires. Le resultat principal est un critere pour l’existence d’un theoreme de la limite centrale pour la statistique des angles entre les points. La preuve utilise une formule exacte reliant la fonction generatrice de telles statistiques au determinant d’une matrice de Toeplitz perturbee.
Sparse phase retrieval: Convex algorithms and limitations

We consider the problem of recovering signals from their power spectral densities. This is a classical problem referred to in literature as the phase retrieval problem, and is of paramount importance in many fields of applied sciences. In general, additional prior information about the signal is required to guarantee unique recovery as the mapping from signals to power spectral densities is not one-to-one. In this work, we assume that the underlying signals are sparse. Recently, semidefinite programming (SDP) based approaches were explored by various researchers. Simulations of these algorithms strongly suggest that signals upto O(n1/2- ϵ) sparsity can be recovered by this technique. In this work, we develop a tractable algorithm based on reweighted l1-minimization that recovers a sparse signal from its power spectral density for significantly higher sparsities, which is unprecedented. We also discuss the limitations of the existing SDP algorithms and provide a combinatorial algorithm which requires significantly fewer ”phaseless” measurements to guarantee recovery.
Exceedances of structural interaction boundaries for random excitation.

A general theory is developed for determining the number of times a given structural interaction boundary is exceeded when the structure is under random excitation. One of the practical problems of concern is that of an airplane encountering a random gust field, where spar design is governed by interaction curves involving combined axial and shear stresses. Based on a normal-type joint distribution curve, a fairly simple basic equation is developed which allows for the rapid evaluation of the number of exceedances of any stipulated interaction curve. The similarity of the equation with Rice's familiar equation for the single variable case is shown. The theory and results are also developed for cases that obey nonnormal distribution laws of the type that are more likely to be found in practice. In addition, exact solutions are obtained for certain special cases of interest.
Coherent frequency comb generation in a silicon nitride microresonator with anomalous dispersion

We observe a transition to a coherent-comb state in a SiN-microresonator with anomalous dispersion. Although ~300 fs pulse trains are generated after line-by-line shaping, the intensity within the microring does not appear to be pulse-like.
Design of Air and Liquid Cooling Systems for Electronic Components Using Concurrent Simulation and Experiment

The design of cooling systems for electronic equipment is getting more involved and challenging due to increase in demand for faster and more reliable electronic systems. Therefore, robust and more efficient design and optimization methodologies are required. Conventional approaches are based on sequential use of numerical simulation and experiment. Thus, they fail to use certain advantages of using both tools concurrently. The present study is aimed at combining simulation and experiment in a concurrent manner such that outputs of each approach drive the other to achieve better engineering design in a more efficient way. In this study, a relatively simple problem, involving heat transfer from multiple heat sources simulating electronic components and located in a horizontal channel, was investigated. Two experimental setups were fabricated for air and liquid cooling experiments to study the effects of different coolants. De-ionized water was used as the liquid coolant in one case and air in the other. The effects of separation distance and flow conditions on the heat transfer and on the fluid flow characteristics were investigated in detail for both coolants. Cooling capabilities of different cooling arrangements were compared and the results from simulations and experiments were combined to create response surfaces and to find the optimal values of the design parameters.
Infrastructure Commons in Economic Perspective

This chapter briefly summarizes a theory (developed in substantial detail elsewhere)1 that explains why there are strong economic arguments for managing and sustaining infrastructure resources in an openly accessible manner. This theory facilitates a better understanding of two related issues: how society benefits from infrastructure resources and how decisions about how to manage or govern infrastructure resources affect a wide variety of public and private interests. The key insights from this analysis are that infrastructure resources generate value as inputs into a wide range of productive processes and that the outputs from these processes are often public goods and nonmarket goods that generate positive externalities that benefit society as a whole. Managing such resources in an openly accessible manner may be socially desirable from an economic perspective because doing so facilitates these downstream productive activities. For example, managing the Internet infrastructure in an openly accessible manner facilitates active citizen involvement in the production and sharing of many different public and nonmarket goods. Over the last decade, this has led to increased opportunities for a wide range of citizens to engage in entrepreneurship, political discourse, social network formation, and community building, among many other activities. The chapter applies these insights to the network neutrality debate and suggests how the debate might be reframed to better account for the wide range of private and public interests at stake.
Fractional spin and the Pauli term

Abstract It has recently been claimed that the inclusion of a Pauli term in (2+1) dimensions gives rise to a new type of anomalous spin term. The form of that term is shown to contradict the structure relations for the inhomogeneous Lorentz group.
Color-kinematics duality and double-copy construction for amplitudes from higher-dimension operators

We investigate color-kinematics duality for gauge-theory amplitudes produced by the pure nonabelian Yang-Mills action deformed by higher-dimension operators. For the operator denoted by F 3, the product of three field strengths, the existence of color-kinematic dual representations follows from string-theory monodromy relations. We provide explicit dual representations, and show how the double-copy construction of gravity amplitudes based on them is consistent with the Kawai-Lewellen-Tye relations. It leads to the amplitudes produced by Einstein gravity coupled to a dilaton field ϕ, and deformed by operators of the form ϕR 2 and R 3. For operators with higher dimensions than F 3, such as F 4-type operators appearing at the next order in the low-energy expansion of bosonic and superstring theory, the situation is more complex. The color structure of some of the F 4 operators is incompatible with a simple color-kinematics duality based on structure constants f abc, but even the color-compatible F 4 operators do not admit the duality. In contrast, the next term in the α′ expansion of the superstring effective action — a particular linear combination of D 2 F 4 and F 5-type operators — does admit the duality, at least for amplitudes with up to six external gluons.
The collapse and reemergence of networks within and between Republics of the Former Soviet Union

Abstract A large body of research explores the characteristics of networks in Western economies. This study primarily analyzes supply networks in Estonia before and after the breakup of the former Soviet Union and the impact of networks on firm performance. Of particular interest is whether firms which had to reestablish networks were better off than those which were able to sustain previously established networks. Significant differences were found in the pre-independence network structures of high and low performing firms. After independence, network structures were not significantly different, with linkages to the former Soviet Union severed for both groups. Successful firms were found to have Estonia-centered customer and supply networks existing before independence, while unsuccessful firms pre-independence networks centered on the Soviet Union.
GAMMA-RAY BURSTS IN CIRCUMSTELLAR SHELLS: A POSSIBLE EXPLANATION FOR FLARES

It is now generally accepted that long-duration gamma-ray bursts (GRBs) are due to the collapse of massive rotating stars. The precise collapse process itself, however, is not yet fully understood. Strong winds, outbursts, and intense ionizing UV radiation from single stars or strongly interacting binaries are expected to destroy the molecular cloud cores that give birth to them and create highly complex circumburst environments for the explosion. Such environments might imprint features on GRB light curves that uniquely identify the nature of the progenitor and its collapse. We have performed numerical simulations of realistic environments for a variety of long-duration GRB progenitors with ZEUS-MP and have developed an analytical method for calculating GRB light curves in these profiles. Though a full, three-dimensional, relativistic magnetohydrodynamical computational model is required to precisely describe the light curve from a GRB in complex environments, our method can provide a qualitative understanding of these phenomena. We find that, in the context of the standard afterglow model, massive shells around GRBs produce strong signatures in their light curves, and that this can distinguish them from those occurring in uniform media or steady winds. These features can constrain the mass of the shell and the properties of the wind before and after the ejection. Moreover, the interaction of the GRB with the circumburst shell is seen to produce features that are consistent with observed X-ray flares that are often attributed to delayed energy injection by the central engine. Our algorithm for computing light curves is also applicable to GRBs in a variety of environments such as those in high-redshift cosmological halos or protogalaxies, both of which will soon be targets of future surveys such as the Joint Astrophysics Nascent Satellite or Lobster.
Computational Geometry: An Introduction

From the reviews: "This book offers a coherent treatment, at the graduate textbook level, of the field that has come to be known in the last decade or so as computational geometry...The book is well organized and lucidly written; a timely contribution by two founders of the field. It clearly demonstrates that computational geometry in the plane is now a fairly well-understood branch of computer science and mathematics. It also points the way to the solution of the more challenging problems in dimensions higher than two."
Aromatic pentafluoro-λ6-sulfanyl (SF5) surfactants: m-SF5(CF2)nC6H4SO3K

The synthesis and characterization of new fluorinated surfactants based on SF5-aromatic system are presented for the first time.
Legal Reform and Loan Repayment: The Microeconomic Impact of Debt Recovery Tribunals in India

In 1993, the Indian government introduced debt recovery tribunals to speed up the resolution of debt recovery claims larger than a threshold. This paper exploits the staggered introduction of tribunals across states and the link between overdues and claim size to implement a differences-in-differences strategy on project loan data. It finds that the tribunals reduced delinquency for the average loan by 28 percent. They also lowered the interest rates charged on larger loans, holding constant borrower quality. This suggests that the speedier processing of debt recovery suits can lower the cost of credit.
FREE-SPACE QUANTUM CRYPTOGRAPHY IN DAYLIGHT

Quantum cryptography is an emerging technology in which two parties may simultaneously generate shared, secret cryptographic key material using the transmission of quantum states of light. The security of these transmissions is based on the inviolability of the laws of quantum mechanics and information-theoretically secure post-processing methods. An adversary can neither successfully tap the quantum transmissions, nor evade detection, owing to Heisenberg's uncertainty principle. In this paper we describe the theory of quantum cryptography, and the most recent results from our experimental free-space system with which we have demonstrated for the first time the feasibility of quantum key generation over a point-to-point outdoor atmospheric path in daylight. We achieved a transmission distance of 0.5 km, which was limited only by the length of the test range. Our results provide strong evidence that cryptographic key material could be generated on demand between a ground station and a satellite (or between two satellites), allowing a satellite to be securely re-keyed on orbit. We present a feasibility analysis of surface-to-satellite quantum key generation.
Social contract, taxation and the standing of deadweight loss

Abstract This paper develops the proposition that the normative design of a good tax system depends on the ethical premise or social contract on which society is taken to operate. This thesis is applied to Lockean entitlement to earnings with its corollary of benefit taxation and to the utilitarian model with its counterpart of maximum welfare or least total sacrifice. Fairness rules including maximin are also noted. For each case the role of tax avoidance and resulting deadweight loss is examined and found of questionable standing. In concluding, a parallel is drawn with the role of punishement in jurisprudence.
The fluorous Swern and Corey–Kim reactions: scope and mechanism

Abstract Protocols for the efficient preparation of 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecafluoro-8-methanesulfenyloctane and 1,1,1,2,2,3,3,4,4-nonafluoro-6-methanesulfenylhexane (fluorous dimethyl sulfide) and for their oxidation to the corresponding sulfoxides (fluorous dimethyl sulfoxide) are reported. The lower molecular weight sulfoxide, in conjunction with oxalyl chloride and Hunig's base, brings about the oxidation of diversely functionalized primary and secondary alcohols to aldehydes and ketones in excellent yield. The fluorous sulfoxide is efficiently recovered for reuse by a simple continuous fluorous extraction and hydrogen peroxide oxidation protocol. The whole process is odor-free. A deuterium-labeling experiment is used to demonstrate that the oxidations take place via the classical Swern mechanism, i.e. by intramolecular hydride abstraction from a sulfur ylid. Corey–Kim oxidations may be performed with the higher molecular weight fluorous sulfide, although recycling is not as efficient.
Seasonal and interannual variations of top‐of‐atmosphere irradiance and cloud cover over polar regions derived from the CERES data set

[1] The daytime cloud fraction derived by the Clouds and the Earth's Radiant Energy System (CERES) cloud algorithm using Moderate Resolution Imaging Spectroradiometer (MODIS) radiances over the Arctic from March 2000 through February 2004 increases at a rate of 0.047 per decade. The trend is significant at an 80% confidence level. The corresponding top-of-atmosphere (TOA) shortwave irradiances derived from CERES radiance measurements show less significant trend during this period. These results suggest that the influence of reduced Arctic sea ice cover on TOA reflected shortwave radiation is reduced by the presence of clouds and possibly compensated by the increase in cloud cover. The cloud fraction and TOA reflected shortwave irradiance over the Antarctic show no significant trend during the same period.
Submillimeter Observations of Titan: Global Measures of Stratospheric Temperature, CO, HCN, HC3N, and the Isotopic Ratios 12C/13C and 14N/15N

Interferometric observations of the atmosphere of Titan were performed with the Submillimeter Array on two nights in 2004 February to investigate the global average vertical distributions of several molecular species above the tropopause. Rotational transitions of CO, isomers of HCN, and HC3N were simultaneously recorded. The abundance of CO is determined to be 51 ± 4 parts per million (ppm), constant with altitude. The vertical profile of HCN is dependent on the assumed temperature but generally increases from 30 parts per billion at the condensation altitude (~83 km) to 5 ppm at ~300 km. Furthermore, the central core of the HCN emission is strong and can be reproduced only if the upper stratospheric temperature increases with altitude. The isotopic ratios are determined to be 12C/13C = 132 ± 25 and 14N/15N = 94 ± 13 assuming the Coustenis & Bezard temperature profile. If the Lellouch temperature profile is assumed, the ratios decrease to 12C/13C = 108 ± 20 and 14N/15N = 72 ± 9. The vertical profile of HC3N is consistent with that derived by Marten et al.
Can We Determine Electric Fields and Poynting Fluxes from Vector Magnetograms and Doppler Measurements

The availability of vector-magnetogram sequences with sufficient accuracy and cadence to estimate the temporal derivative of the magnetic field allows us to use Faraday’s law to find an approximate solution for the electric field in the photosphere, using a Poloidal–Toroidal Decomposition (PTD) of the magnetic field and its partial time derivative. Without additional information, however, the electric field found from this technique is under-determined – Faraday’s law provides no information about the electric field that can be derived from the gradient of a scalar potential. Here, we show how additional information in the form of line-of-sight Doppler-flow measurements, and motions transverse to the line-of-sight determined with ad-hoc methods such as local correlation tracking, can be combined with the PTD solutions to provide much more accurate solutions for the solar electric field, and therefore the Poynting flux of electromagnetic energy in the solar photosphere. Reliable, accurate maps of the Poynting flux are essential for quantitative studies of the buildup of magnetic energy before flares and coronal mass ejections.
Disintegration of projective measures

In this paper, we study a class of quasi-invariant measures on paths generated by discrete dynamical systems. Our main result characterizes the subfamily of these measures which admit a certain disintegration. This is a disintegration with respect to a random walk Markov process which is indexed by the starting point of the paths. Our applications include wavelet constructions on Julia sets of rational maps on the Riemann sphere.
Applications of ( a , b )-continued fraction transformations

We describe a general method of arithmetic coding of geodesics on the modular surface based on the study of one-dimensional Gauss-like maps associated to a two-parameter family of continued fractions introduced in [Katok and Ugarcovici. Structure of attractors for ( a , b )-continued fraction transformations. J. Modern Dynamics 4 (2010), 637–691]. The finite rectangular structure of the attractors of the natural extension maps and the corresponding ‘reduction theory’ play an essential role. In special cases, when an ( a , b )-expansion admits a so-called ‘dual’, the coding sequences are obtained by juxtaposition of the boundary expansions of the fixed points, and the set of coding sequences is a countable sofic shift. We also prove that the natural extension maps are Bernoulli shifts and compute the density of the absolutely continuous invariant measure and the measure-theoretic entropy of the one-dimensional map.
An R&D Race with Knowledge Accumulation

I develop a model of an R&D race with knowledge accumulation. My model does not inherit the memorylessness property of the exponential distribution that troubles existing models of R&D races. Hence, firms' knowledge stocks are no longer irrelevant to their behavior during the R&D race, and knowledge accumulation has strategic implications. In this more general setting, I obtain results that stand in marked contrast to the previous literature. In particular, under some conditions, the firm that is behind in the race engages in catch-up behavior. This pattern of strategic interactions (action-reaction) is consistent with empirical research. Copyright 2003 by the RAND Corporation.
The synthesis of new binucleating polyaza macrocyclic and macrobicyclic ligands : dioxygen affinities of the cobalt complexes

Abstract Six macrocyclic and five macrobicyclic Schiff bases have been synthesized by condensation of rigid dialdehydes with diethylenetriamine or tris (aminoethyl) amine, and have been reduced to the corresponding saturated hexaaza macrocyclic complexes or octaaza macrobicyclic complexes. Six of the dicobalt complexes of these new ligands were found to be oxygen carriers.
Ground based VLF observations near L = 2.5 during the Halloween 2003 storm

[1] Ground based recordings at Palmer Station, Antarctica (L = 2.44) provide rare observations of VLF waves at low L during and in the aftermath of the Halloween 2003 superstorms. VLF observations in the morning magnetic local time sector for Oct 29 to Nov 5 2003 are compared with daily global average changes in the electron radiation belts near the slot region. Wave activity observed at Palmer was remarkably intense during this period and included discrete chorus emissions, mid-latitude hiss as well as an unusual form of hiss extending up to ∼15 kHz suggestive of auroral hiss. While the inner edge of the new radiation belt formed near L = 2, analysis of VLF data indicate that chorus was primarily confined outside L ≈ 2.75.
Independence of ℓ in Lafforgue's theorem

Abstract Let X be a smooth curve over a finite field of characteristic p, let l≠p be a prime number, and let L be an irreducible lisse Q l -sheaf on X whose determinant is of finite order. By a theorem of L. Lafforgue, for each prime number l′≠p, there exists an irreducible lisse Q l′ -sheaf L ′ on X which is compatible with L , in the sense that at every closed point x of X, the characteristic polynomials of Frobenius at x for L and L ′ are equal. We prove an “independence of l” assertion on the fields of definition of these irreducible l′-adic sheaves L ′ : namely, that there exists a number field F such that for any prime number l′≠p, the Q l′ -sheaf L ′ above is defined over the completion of F at one of its l′-adic places.
Zeolite supported rhodium carbonyls from Rh(allyl)3 and their use as 1-hexene hydroformylation catalysts

Abstract Rhodium has been introduced to protonated zeolite Y (HY) and partially protonated zeolite Y (5% HNaY) as the tris-allyl complex, Rh(C3H5)3. The resulting zeolite, RhHY or RhNaY, may be reduced in CO to yield Rh(CO)2+ or Rh6(CO)16 depending on the reaction conditions. Reaction with phosphines suggests that rhodium lies both within the zeolite framework and on the zeolite surface. When the zeolite supported phosphine complexes are used as solution hydroformylation catalysts, all of the observed activity appears to come from the solution phase as rhodium is leached from the support.
Faster randomized consensus with an oblivious adversary

Two new algorithms are given for randomized consensus in a shared-memory model with an oblivious adversary. Each is based on a new construction of a conciliator, an object that guarantees termination and validity, but that only guarantees agreement with constant probability. The first conciliator assumes unit-cost snapshots and achieves agreement among n processes with probability $$1-\epsilon $$ 1 - ∈ in $$O(\log ^* n + \log (1/\epsilon ))$$ O ( log ? n + log ( 1 / ∈ ) ) steps for each process. The second uses ordinary multi-writer registers, and achieves agreement with probability $$1-\epsilon $$ 1 - ∈ in $$O(\log \log n + \log (1/\epsilon ))$$ O ( log log n + log ( 1 / ∈ ) ) steps. Combining these constructions with known results gives randomized consensus for arbitrarily many possible input values using unit-cost snapshots in $$O(\log ^* n)$$ O ( log ? n ) expected steps and randomized consensus for up to $$(\log n)^{O(\log \log \log n)}$$ ( log n ) O ( log log log n ) possible input values using ordinary registers in $$O(\log \log n)$$ O ( log log n ) expected steps.