cssi/SciSciGPT-SciSciNet huggingface dataset:
Swayed by friends or by the crowd

We have conducted three empirical studies of the effects of friend recommendations and general ratings on how online users make choices. We model and quantify how a user deciding between two choices trades off an additional rating star with an additional friend's recommendation when selecting an item. We find that negative opinions from friends are more influential than positive opinions, and people exhibit "more random" behavior in their choices when the decision involves less cost and risk. Our results are quite general in the sense that people across different demographics trade off recommendations from friends and ratings from the general public in a similar fashion.
Equilibrium existence in group contests

We prove the existence of pure strategy Bayesian equilibria in group contests under individual-level and group-level private information. For the latter type, we develop a novel approach reducing group contests to contests between individuals with multi-dimensional types, with far-reaching implications for the existence of equilibrium in various group contest settings, including the case of complete information.
Alignment by Maximization of Mutual Information

A new information-theoretic approach is presented for finding the pose of an object in an image. The technique does not require information about the surface properties of the object, besides its shape, and is robust with respect to variations of illumination. In our derivation few assumptions are made about the nature of the imaging process. As a result the algorithms are quite general and may foreseeably be used in a wide variety of imaging situations. Experiments are presented that demonstrate the approach registering magnetic resonance (MR) images, aligning a complex 3D object model to real scenes including clutter and occlusion, tracking a human head in a video sequence and aligning a view-based 2D object model to real images. The method is based on a formulation of the mutual information between the model and the image. As applied here the technique is intensity-based, rather than feature-based. It works well in domains where edge or gradient-magnitude based methods have difficulty, yet it is more robust than traditional correlation. Additionally, it has an efficient implementation that is based on stochastic approximation.
Partitions with parts in a finite set

Let A be a nonempty finite set of relatively prime positive integers, and let PA (n) denote the number of partitions of n with parts in A. An elementary arithmetic argument is used to prove the asymptotic formula PA((n) = (,A a) (k1)! + 0 (nk2)Let A be a nonempty set of positive integers. A partition of a positive integer n with parts in A is a representation of n as a sum of not necessarily distinct elements of A. Two partitions are considered the same if they differ only in the order of their summands. The partition function of the set A, denoted PA (n), counts the number of partitions of n with parts in A. If A is a finite set of positive integers with no common factor greater than 1, then every sufficiently large integer can be written as a sum of elements of A (see Nathanson [3] and Han, Kirfel, and Nathanson [2]), and so PA (n) > 1 for all n > no. In the special case that A is the set of the first k integers, it is known that nk-i PA(n) k!(k 1)! Erdos and Lehner [1] proved that this asymptotic formula holds uniformly for k = o(n1/3). If A is an arbitrary finite set of relatively prime positive integers, then PA (1 (k1)!' (1) PA (2J \HalEAa) (kThe usual proof of this result (Netto [4], Polya-Szeg6 [5, Problem 27]) is based on the partial fraction decomposition of the generating function for PA(n). The purpose of this note is to give a simple, purely arithmetic proof of (1). We define PA(O) = 1. Theorem 1. Let A = {al,... , ak} be a set of k relatively prime positive integers, that is, gcd(A) = (a,,... , ak)=1. Received by the editors June 5, 1998. 2000 Mathematics Subject Classification. Primary 11P81; Secondary 05A17, 11B34.
The first miniquasar

We investigate the environmental impact of the first active galactic nuclei that may have formed ∼150 Myr after the big bang in low-mass ∼10 6 M θ minihaloes. Using ENZO, an adaptive-mesh refinement cosmological hydrodynamics code, we carry out three-dimensional simulations of the radiative feedback from 'miniquasars' powered by intermediate-mass black holes. We follow the non-equilibrium multispecies chemistry of primordial gas in the presence of a point source of X-ray radiation, which starts shining in a rare high-cr peak at z = 21 and emits a power-law spectrum in the 0.2-10 keV range. We find that, after one Salpeter time-scale, the miniquasar has heated up the simulation box to a volume-averaged temperature of 2800 K. The mean electron and H 2 fractions are now 0.03 and 4 x 10 -5 : the latter is 20 times larger than the primordial value, and will delay the build-up of a uniform ultraviolet (UV) photodissociating background. The net effect of the X-rays is to reduce gas clumping in the intergalactic medium (IGM) by as much as a factor of 3. While the suppression of baryonic infall and the photoevaporation of some halo gas lower the gas mass fraction at overdensities 8 in the range 20-2000, enhanced molecular cooling increases the amount of dense material at δ > 2000. In many haloes within the proximity of our miniquasar, the H 2 -boosting effect of X-rays is too weak to overcome heating, and the cold and dense gas mass actually decreases. We find little evidence for an entropy floor in gas at intermediate densities preventing gas contraction and H 2 formation: we show, instead, that molecular cooling can affect the dynamics of baryonic material before it has fallen into the potential well of dark matter haloes and virialized. Overall, the radiative feedback from X-rays enhances gas cooling in lower-cr peaks that are far away from the initial site of star formation, thus decreasing the clustering bias of the early pregalactic population, but does not appear to dramatically reverse or promote the collapse of pregalactic clouds as a whole.
Rendezvous regions: a scalable architecture for service location and data-centric storage in large-scale wireless networks

Summary form only given. In large-scale wireless networks such as mobile ad hoc and sensor networks, efficient and robust service discovery and data-access mechanisms are both essential and challenging. Rendezvous-based mechanisms provide a valuable solution for provisioning a wide range of services. We describe rendezvous regions (RRs) - a novel scalable rendezvous-based architecture for wireless networks. RR is a general architecture proposed for service location and bootstrapping in ad hoc networks, in addition to data-centric storage, configuration, and task assignment in sensor networks. In RR the network topology is divided into geographical regions, where each region is responsible for a set of keys representing the services or data of interest. Each key is mapped to a region based on a hash-table-like mapping scheme. A few elected nodes inside each region are responsible for maintaining the mapped information. The service or data provider stores the information in the corresponding region and the seekers retrieve it from there. We run extensive detailed simulations, and high-level simulations and analysis, to investigate the design space, and study the architecture in various environments including node mobility and failures. We evaluate it against other approaches to identify its merits and limitations. The results show high success rate and low overhead even with dynamics. RR scales to large number of nodes and is highly robust and efficient to node failures. It is also robust to node mobility and location inaccuracy with a significant advantage over point-based rendezvous mechanisms.
Hierarchical Nearest-Neighbor Gaussian Process Models for Large Geostatistical Datasets.

AbstractSpatial process models for analyzing geostatistical data entail computations that become prohibitive as the number of spatial locations become large. This article develops a class of highly scalable nearest-neighbor Gaussian process (NNGP) models to provide fully model-based inference for large geostatistical datasets. We establish that the NNGP is a well-defined spatial process providing legitimate finite-dimensional Gaussian densities with sparse precision matrices. We embed the NNGP as a sparsity-inducing prior within a rich hierarchical modeling framework and outline how computationally efficient Markov chain Monte Carlo (MCMC) algorithms can be executed without storing or decomposing large matrices. The floating point operations (flops) per iteration of this algorithm is linear in the number of spatial locations, thereby rendering substantial scalability. We illustrate the computational and inferential benefits of the NNGP over competing methods using simulation studies and also analyze fores...
Resolving boosted jets with XCone

We show how the recently proposed XCone jet algorithm [1] smoothly interpolates between resolved and boosted kinematics. When using standard jet algorithms to reconstruct the decays of hadronic resonances like top quarks and Higgs bosons, one typically needs separate analysis strategies to handle the resolved regime of well-separated jets and the boosted regime of fat jets with substructure. XCone, by contrast, is an exclusive cone jet algorithm that always returns a fixed number of jets, so jet regions remain resolved even when (sub)jets are overlapping in the boosted regime. In this paper, we perform three LHC case studies — dijet resonances, Higgs decays to bottom quarks, and all-hadronic top pairs — that demonstrate the physics applications of XCone over a wide kinematic range.
Band gap engineering in finite elongated graphene nanoribbon heterojunctions: Tight-binding model

A simple model based on the divide and conquer rule and tight-binding (TB) approximation is employed for studying the role of finite size effect on the electronic properties of elongated graphene nanoribbon (GNR) heterojunctions. In our model, the GNR heterojunction is divided into three parts: a left (L) part, middle (M) part, and right (R) part. The left part is a GNR of width WL, the middle part is a GNR of width WM, and the right part is a GNR of width WR. We assume that the left and right parts of the GNR heterojunction interact with the middle part only. Under this approximation, the Hamiltonian of the system can be expressed as a block tridiagonal matrix. The matrix elements of the tridiagonal matrix are computed using real space nearest neighbor orthogonal TB approximation. The electronic structure of the GNR heterojunction is analyzed by computing the density of states. We demonstrate that for heterojunctions for which WL = WR, the band gap of the system can be tuned continuously by varying the l...
Through the looking glass--a new world of proteins enabled by chemical synthesis.

‘Chemical ligation’ – the regioselective and chemoselective covalent condensation of unprotected peptide segments – has enabled the synthesis of polypeptide chains of more than 200 amino acids. An efficient total chemical synthesis of the insulin molecule has been devised on the basis of a key ester-linked intermediate that is chemically converted to fully active human insulin. Enzyme molecules of defined covalent structure and with full enzymatic activity have been prepared and characterized by high-resolution X-ray crystallography. A ‘glycoprotein mimetic’ of defined chemical structure and with a mass of 50,825 Da, has been prepared and shown to have full biological activity and improved pharmacokinetic properties. d-Protein molecules that are the mirror images of proteins found in the natural world have been prepared by total chemical synthesis. Racemic protein mixtures, consisting of the d-enantiomers and l-enantiomers of a protein molecule, form highly ordered centrosymmetric crystals with great ease; this has enabled the determination of the crystal structures of recalcitrant protein molecules. A protein with a novel linear-loop covalent topology of the peptide chain has been designed and synthesized and its structure determined by facile crystallization as the quasi-racemate with the d-form of the native protein molecule. We have developed an optimized total chemical synthesis of biologically active vascular endothelial growth factor-A; total synthesis of the mirror-image protein will be used to systematically develop d-protein antagonists of this important growth factor. The total chemical synthesis of proteins is now a practical reality and enables access to a new world of protein molecules. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.
Coordinating Public Debt Management with Fiscal and Monetary Policies : An Analytical Framework

This paper proposes a sovereign asset and liability management framework for analyzing the inter-relationships between debt management, fiscal and monetary policies. It illustrates the consequences of uncoordinated policy mix and extends Sargent and Wallace (1981 and 1993) by including debt management. Examples of policy games played by fiscal, monetary, and debt management authorities reinforce the importance of policy separation and coordination to prevent domination by one authority over another which could lead to inconsistent policy mix.
Radiatively inefficient accretion: breezes, winds and hyperaccretion

We reformulate the adiabatic inflow–outflow solution (ADIOS) model for radiatively inefficient accretion flows, treating the inflow and outflow zones on an equal footing. For purely adiabatic flows (i.e. with no radiative losses), we show that the mass flux in each zone must satisfy with n= 1, in contrast to previous work in which 0 < n < 1 is a free parameter but in rough agreement with numerical simulations. We also demonstrate that the resulting two-zone ADIOS models are not dynamically self-consistent without the introduction of an energy source close in to the central regions of the flow; we identify this with the energy liberated by accretion. We explore the parameter space of non-radiative models and show that both powerful winds and gentle breezes are possible. When small radiative losses (with fixed efficiency) are included, any centrally injected energy flux is radiated away and the system reverts to a power-law behaviour with n≲ 1, where n falls in a small range determined by the fractional level of radiative losses. We also present an ADIOS model for hypercritical (super-Eddington) disc accretion, in which the radiative losses are closely related to the flow geometry. We suggest that hyperaccretion can lead to either winds or breezes.
Precision measurement with gravity

Summary form only given. The author describes some of the work directed towards the measurement of G, g, and g/spl mu//spl nu/. A number of recently completed measurements of G have had, and a number of ongoing measurements have, the aim of improving the accuracy of the first of these "gs" from today's 1.5 parts in 10/sup 2/ to better than one part in 10/sup 4/ (to somewhat better than the accuracy with which it was thought to be known 10 years ago). By contrast, our ability to accurately measure the second "g" has, during the past forty years, enjoyed a remarkable 3 orders-of-magnitude improvement. Lastly, sometime in the next decade or so, the final "g" can be expected to provide us with new insights into things such as the formation of massive black holes and galaxy evolution as well as a variety of other objects of astrophysical interest. The role of precision measurement science in carrying out these measurements, and, indeed, in underpinning all of scientific progress, is highlighted. Finally, the commonality of these three different measurements is pointed out.
Low-Wavenumber Forcing and Turbulent Energy Dissipation

A popular method of forcing the fluid in Direct Numerical Simulations of turbulence is to take the body force proportional to the projection of the velocity of the fluid onto its lowest Fourier modes, while keeping the injected external power constant. In this paper we perform a simple but rigorous analysis to establish bounds on the relationship between the energy dissipation rate and the resulting Reynolds number for this type of forcing. While this analysis cannot give detailed information of the energy spectrum, it does provide some indication of the balance of energy between the lower, directly forced, modes, and those excited by the cascade.
Auto-Sizing Neural Networks: With Applications to n-gram Language Models

Neural networks have been shown to improve performance across a range of natural-language tasks. However, designing and training them can be complicated. Frequently, researchers resort to repeated experimentation to pick optimal settings. In this paper, we address the issue of choosing the correct number of units in hidden layers. We introduce a method for automatically adjusting network size by pruning out hidden units through‘1,1 and ‘2,1 regularization. We apply this method to language modeling and demonstrate its ability to correctly choose the number of hidden units while maintaining perplexity. We also include these models in a machine translation decoder and show that these smaller neural models maintain the significant improvements of their unpruned versions.
Oriented edge forests for boundary detection

We present a simple, efficient model for learning boundary detection based on a random forest classifier. Our approach combines (1) efficient clustering of training examples based on a simple partitioning of the space of local edge orientations and (2) scale-dependent calibration of individual tree output probabilities prior to multiscale combination. The resulting model outperforms published results on the challenging BSDS500 boundary detection benchmark. Further, on large datasets our model requires substantially less memory for training and speeds up training time by a factor of 10 over the structured forest model.
A Hessenberg Generalization of the Garsia-Procesi Basis for the Cohomology Ring of Springer Varieties

The Springer variety is the set of flags stabilized by a nilpotent operator. In 1976, T.A. Springer observed that this variety's cohomology ring carries a symmetric group action, and he offered a deep geometric construction of this action. Sixteen years later, Garsia and Procesi made Springer's work more transparent and accessible by presenting the cohomology ring as a graded quotient of a polynomial ring. They combinatorially describe an explicit basis for this quotient. The goal of this paper is to generalize their work. Our main result deepens their analysis of Springer varieties and extends it to a family of varieties called Hessenberg varieties, a two-parameter generalization of Springer varieties. Little is known about their cohomology. For the class of regular nilpotent Hessenberg varieties, we conjecture a quotient presentation for the cohomology ring and exhibit an explicit basis. Tantalizing new evidence supports our conjecture for a subclass of regular nilpotent varieties called Peterson varieties.
Can a corporate network and news sentiment improve portfolio optimization using the Black–Litterman model?

The Black–Litterman (BL) model for portfolio optimization combines investors’ expectations with the Markowitz framework. The BL model is designed for investors with private information or knowledge of market behaviour. In this paper, I propose a method where investors’ expectations are based on either news sentiment using high-frequency data or on a combination of accounting variables; financial analysts’ recommendations, and corporate social network indicators with quarterly data. The results show promise when compared to a market portfolio. I also provide recommendations for trading strategies using the results of this BL model.
Nonlinear model reduction based on the finite element method with interpolated coefficients: Semilinear parabolic equations

For nonlinear reduced-order models (ROMs), especially for those with high-order polynomial nonlinearities or nonpolynomial nonlinearities, the computational complexity still depends on the dimension of the original dynamical system. To overcome this issue, we develop an efficient finite element (FE) discretization algorithm for nonlinear ROMs. The proposed approach approximates the nonlinear function by its FE interpolant, which makes the inner product evaluations in generating the nonlinear terms computationally cheaper than that in the standard FE discretization. Due to the separation of spatial and temporal variables in the FE interpolation, the discrete empirical interpolation method (DEIM) can be directly applied on the nonlinear functions in the same manner as that in the finite difference setting. Therefore, the main computational hurdles for applying the DEIM in the FE context are conquered. We also establish a rigorous asymptotic error estimation, which shows that the proposed approach achieves the same accuracy as that of the standard FE method under certain smoothness assumptions of the nonlinear functions. Several numerical tests are presented to validate the proposed method and verify the theoretical results. © 2015 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 31: 1713–1741, 2015
Capture of irregular satellites via binary planetesimal exchange reactions in migrating planetary systems

By logging encounters between planetesimals and planets, we compute the distribution of encounters in a numerically integrated two-planet system that is migrating due to interactions with an exterior planetesimal belt. Capture of an irregular satellite in orbit about a planet through an exchange reaction with a binary planetesimal is only likely when the binary planetesimal undergoes a slow and close encounter with the planet. Taking care to consider where a planet-orbit-crossing binary planetesimal would first be tidally disrupted, we estimate the probability of both tidal disruption and irregular satellite capture. We estimate that the probability that the secondary of a binary planetesimal is captured and becomes an irregular satellite about a Neptune mass outer planet is about 1/100 for binaries with masses and separations similar to transneptunian planetesimal binaries. Scaling functions are given allowing probabilities to be estimated for satellite capture from binary planetesimals with other masses, mass ratios and separations. This capture probability is only weakly dependent upon the binary's tidal disruption radius. We find that the probability that a satellite is captured by the inner planet is one to two orders of magnitude lower than by the outer planet. If young exoplanetary debris discs contain a population of binary planetesimals, then an outwards migrating outer planet should host a recently captured irregular satellite population.
Return-of-Premium Endorsements for Living-Benefits Insurance Policies: Rational or Irrational?

Insurance companies selling Critical Illness, Disability, and Long-Term Care insurance policies typically offer consumers the option to purchase an endorsement that returns the nominal value of all premiums paid (over the life of the policy) if the policy is not used during the policy term. The endorsement costs the policyholder extra money. Simple calculations show that it is prima facie irrational to purchase the endorsement since the conditional implied rate-of-return on the asset (return-of-premium endorsement) is almost twice as worse as a market index; the unconditional rate of return is even worse. Behavioral explanations for the purchase of these otherwise irrational endorsements are considered.
Asymmetric Synthetic Access to the Hetisine Alkaloids: Total Synthesis of (+)-Nominine

A dual cycloaddition strategy for the synthesis of the hetisine alkaloids has been developed, illustrated by a concise asymmetric total synthesis of (+)-nominine (7). The approach relies on an early-stage intramolecular 1,3-dipolar cycloaddition of a 4-oxido-isoquinolinium betaine dipole with an ene-nitrile dipolarophile. Subsequent late-stage pyrrolidine-induced dienamine isomerization/Diels-Alder cascade allows for rapid construction of the carbon--nitrogen polycyclic skeleton within this class of C(20)-diterpenoid alkaloids.
An Analytical Model for Solute Transport in Unsaturated Flow through a Single Fracture and Porous Rock Matrix

Exact analytical solutions are presented for solute transport in an unsaturated fracture and porous rock matrix. The problem includes advective transport in the fracture and rock matrix as well as advective and diffusive fracture-matrix exchange. Linear sorption in the fracture and matrix and radioactive decay are also treated. The solution is for steady, uniform transport velocities within the fracture and matrix, but allows for independent specification of each of the velocities. The problem is first solved in terms of the solute concentrations that result from an instantaneous point source. Superposition integrals are then used to derive the solute mass flux at a fixed downstream position from an instantaneous point source and for the solute concentrations that result from a continuous point source. Solutions are derived for cases with the solute source in the fracture and the solute source in the matrix. The analytical solutions are closed-form and are expressed in terms of algebraic functions, exponentials, and error functions. Comparisons between the analytical solutions and numerical simulations, as well as sensitivity studies, are presented. Increased sensitivity to cross-flow and solute source location is found for increasing Peclet number. The numerical solutions are found to compare well with the analytical solutions at lower Peclet numbers ,but show greater deviation at higher Peclet numbers.
Enhanced alcohol-seeking behavior by nicotine in the posterior ventral tegmental area of female alcohol-preferring (P) rats: modulation by serotonin-3 and nicotinic cholinergic receptors

Rationale Alcohol and nicotine co-use can reciprocally promote self-administration and drug-craving/drug-seeking behaviors. To date, the neurocircuitry in which nicotine influences ethanol (EtOH) seeking has not been elucidated. Clinical and preclinical research has suggested that the activation of the mesolimbic dopamine system is involved in the promotion of drug seeking. Alcohol, nicotine, and serotonin-3 (5-HT3) receptors interact within the posterior ventral tegmental area (pVTA) to regulate drug reward. Recently, our laboratory has reported that systemic administration of nicotine can promote context-induced EtOH seeking.
On the generalized Borel transform and its application to the statistical mechanics of macromolecules

We present a new integral transform called the generalized Borel transform (GBT) and show how to use it to compute distribution functions used to describe the statistical mechanics of macromolecules. For this purpose, we choose the random flight model (RFM) of macromolecules and show that the application of the GBT to this model leads to the exact expression of the polymer propagator (two-point correlation function) from which all the statistical properties of the model can be obtained. We also discuss the mathematical simplicity of the GBT and its applicability to macromolecules with other topologies.
Coupling between a coherent structure and fine-scale turbulence.

Our direct numerical simulations show that a coherent structure (scrC) in an initially fine-scale homogeneous, isotropic turbulent field breeds secondary structures in its vicinity. These are organized. Shaped like concentric spiral threads perpendicular to the axis of scrC, each is found to be highly polarized with the azimuthal vorticity component being dominant. The threads occur in pairs, and the polarization typically alternates between adjacent threads. Above a critical value (\ensuremath{\approxeq}1000) of Re\ensuremath{\equiv}${\mathrm{\ensuremath{\Gamma}}}_{\mathit{s}\mathit{c}\mathit{r}\mathit{C}}$/\ensuremath{\nu} (${\mathrm{\ensuremath{\Gamma}}}_{\mathit{s}\mathit{c}\mathit{r}\mathit{C}}$ is circulation, \ensuremath{\nu} is kinematic viscosity) a small number of circulation-rich threads emerge as a result of the evolution. The secondary structures are of both practical and theoretical importance. For Reg${\mathrm{Re}}_{\mathrm{crit}}$, the strongest threads excite bending waves on the axis of scrC. For Re\ensuremath{\gg}${\mathrm{Re}}_{\mathrm{crit}}$, scrC is eventually destroyed. We believe that this feedback phenomenon is of critical importance for the rearrangement of coherent structures (CS) and transition to turbulence in shear flows such as plane, circular, and elliptic jets. Turbulent mixing near scrC is due to entrainment and ejection of fluid by the threads. Local isotropy assumption cannot be applied near a CS, because our results show anisotropy in a layer surrounding scrC. The threads are shown to be the combined result of three mechanisms: (1) azimuthal alignment of small-scale vorticity by the strain rate field of scrC; (2) merger (pairing) and axisymmetrization as in two-dimensional turbulent flows, enabled by the alignment; and (3) polarization by differential rotation.
Reexamination of the C2H4F+ potential surface. the status of the classical 2-fluoroethyl cation: a local minimum or transition structure?

Abstract According to ab initio molecular orbital calculations carried out with full geometry optimization at the MP2/6–31G ** level, the classical 2-fluoroethyl cation, FCH 2 CH 2 + , is a transition structure for H-scrambling in CH 3 CHF + . Single point MP4/6–31G ** calculations at the optimized geometries predict the cyclic ethylene fluoronium ion to lie 24.2 kcal mol −1 above CH 3 CHF + and 5.4 kcal mol −1 below the 2-fluoroethyl cation. ΔG‡ for ring opening of the cyclic fluoronium ion at -60° is estimated to be ca 15 kcal mol −1 . This barrier is largely attributable to the powerful negative fluorine hyperconjugation in the transition state as described by Hoffmann and coworkers. When electron correlation effects are ignored a qualitatively different potential surface is obtained on which the 2-fluoroethyl cation is calculated to be a local minimum separated from the stable 1-fluoroethyl cation by an H-bridged transition state.
Rational herding in financial economics

Abstract This paper briefly describes recent papers on the economics of rational herding in financial markets. Some models can predict perfect herding, in which rational agents all act alike without any countervailing force. Such herding typically arises either from direct payoff externalities (negative externalities in bank runs; positive externalities in the generation of trading liquidity or in information acquisition), principal-agent problems (based on managerial desire to protect or signal reputation), or informational learning (cascades). The paper also provides a few pointers to related literature and suggests issues to be addressed in future research.
IMF Conditionality as Investment Regulation: A Theoretical Analysis

The International Monetary Fund (IMF) was created in 1944 to administer a codified system of fixed exchange rates, and thereby promote a more stable world. In the 1970s, fixed exchange rates were abandoned, leading the IMF to seek new tasks. The IMFs modern role is as a long-term lender to developing countries with chronic balance of payments problems. The IMFs prime tool of influence is conditionality: the provision of credit only where the debtor country meets certain criteria, or enacts certain policies. This article examines the intersection between the IMFs conditionality policies and foreign investment. Although not designed to regulate foreign investment, the IMF has often required capital liberalization as a condition of credit. This article explores the implications of such conditionality and finds it problematic. Investment conditionality is outside the IMFs mandate, difficult to reconcile with existing instruments of investment regulation, inimical to democracy and ineffective at ensuring stabl...
The Origins and Physical Properties of the Complex of Local Interstellar Clouds

The Complex of Local Interstellar Clouds (CLIC) is a relatively tight grouping of low density, warm, partially ionized clouds within about 30 pc of the Solar System. The Local Interstellar Cloud (LIC) is the cloud observed on most lines of sight and may be the cloud that immediately surrounds our Solar System, the properties of which set the outer boundary conditions of the heliosphere. Using absorption line data toward nearby stars, in situ observations of inflowing interstellar gas from spacecraft in the Solar System, and theoretical modeling of the interstellar radiation field and radiative transfer, we can deduce many characteristics of the LIC. We find that the LIC is partially ionized with modest electron density, n e ≈0.07 cm−3. The combination of its temperature and ionization favor photoionization/thermal equilibrium over a non-equilibrium cooling cloud picture. The abundances in the LIC suggest moderate dust destruction for silicate dust but complete destruction of carbonaceous grains. An origin for the LIC as a density enhancement in the ambient medium that has been overrun by a shock seems likely, while its velocity away from the Sco-Cen association points to a possible connection to that region and the Loop I bubble.
Asymmetric synthesis of unusual amino acids: Synthesis of optically pure isomers of β-methylphenylalanine

Abstract All the four individual isomers of β-methylphenylalanine have been synthesized in very high optical purities by utilizing in part the chiral imide enolate bromination methodology of Evans and co-workers.
Stereocontrolled allylation of 2-amino-2-deoxy sugar derivatives by a free-radical procedure

Abstract Preparative routes for anomerically specific 1- C -allylation of 2-amino-2-deoxy sugars have been evaluated in a comparative study of various N -substituents and aglycons as precursors for glycosyl radicals that effectively capture an allyl group from allyltributyltin. The crystalline triacetate 4 of 3-(2-acetamido-2-deoxy- α - d -glucopyranosyl)-1-propene ( 6 ) was obtained in 70% yield when 2-acetamido-3,4,6-tri- O -acetyl-2-deoxy- α - d -glucopyranosyl chloride ( 1 ) was treated with allyltributyltin under free-radical conditions, whereas the corresponding bromide 3 led only to an oxazolidine derivative; the β -1-ethylxanthate analogue of 1 gave 4 , but in only 25% yield. The 2-trifluoroacetamido 1-bromide analogue of 1 was also an effective radical source, giving the 2-trifluoroacetamido analogue 8 of 4 in 60% yield. The free amino analogue 7 of 4 was conveniently obtained via the 2- p -methoxybenzylideneamino 1-bromide analogue of 1 . Use of 3,4,6-tri- O -acetyl-2-deoxy-2-phthalimido- β - d -glucopyranosyl bromide as radical precursor allowed stereospecific access to β -1- C -allyl derivatives of the amino sugar. The crystalline galactosamine analogue 12 of 4 was obtained by using the galacto analogue of chloride 1 , but the corresponding manno chloride gave only an oxazoline product. The 1- C -allylated amino sugar derivatives are conformationally more mobile than derivatives not having a 1- C -linked substituent.
Pd(0)-Mediated couplings of aryl nonaflates and triflates with diphenylphosphine-borane. Preparation of BH3-stabilized, unsymmetrical triarylphosphines

Abstract Exposure of an aryl nonaflate or triflate to diphenylphosphine-borane in the presence of catalytic Pd(PPh 3 ) 4 in CH 3 CN at 40° leads to good isolated yields of triarylphosphines uncomplicated by autoxidation.
News spillovers from the Greek debt crisis: Impact on the Eurozone financial sector

Abstract We examine the impact of changes in Greek sovereign yield spreads on abnormal returns of financial sector stocks for a sample of Eurozone countries, during the Greek debt crisis. We find that increases in yield spreads are associated with negative abnormal returns on financial stocks in the Portugal, Spain and Netherlands. These abnormal returns are driven in part by ratings downgrades and other unfavorable news announcements about Greece. We isolate the effects of known transmission channels–impairment of financial firms’ asset base due to cross-holdings of Greek bonds, from increases in domestic interest rates and higher funding costs. Our analysis indicates that news events lead to spillovers in excess of what can be explained by these channels of transmission.
Sample complexity for topology estimation in networks of LTI systems

This paper proposes a consistent and computationally efficient FFT-based algorithm for inferring the network topology where each node in the network is associated to a wide-sense stationary, ergodic, Gaussian process. Each edge of the tree network is characterized by a linear, time-invariant dynamical system and additive white Gaussian noise. The proposed algorithm uses Bartlett's procedure to produce periodogram estimates of cross power spectral densities between processes. Under appropriate assumptions, we prove that the number of vector-valued samples from a single sample path required for consistent estimation is polylogarithmic in the number of nodes in the network. Thus, the sample complexity is low. Our proof uses properties of spectral estimates and analysis for learning tree-structured graphical models.
Monetary Rules for Commodity Traders

The paper develops a model of a small economy that trades commodities whose world prices fluctuate exogenously, and studies its implications for monetary policy. It derives analytical characterizations of optimal Ramsey and flexible price allocations under both perfect risk sharing and financial autarky. This allows the paper to identify the crucial roles of production structure, price elasticities, and capital mobility in monetary policy evaluation. In a calibrated example, impulse-responses under PPI targeting track flexible price allocations closely, but can diverge greatly from Ramsey allocations when risk sharing is perfect and intratemporal elasticities are high. In those cases, policy rules that stabilize real exchange rates more than PPI targeting can deliver higher welfare. But PPI targeting is a clear winner under portfolio autarky.
Commentary: teaching health centers and the path to graduate medical education reform.

The primary-care-oriented Teaching Health Center Graduate Medical Education (THCGME) program funded by the Patient Protection and Affordable Care Act of 2010 offers opportunities to explore alternative solutions to such graduate medical education (GME) policy issues as institutional indirect educational costs, variations in trainee-related productivity gains, and the program costs of GME innovations. THCGME reporting requirements may also provide data on the impact of various educational innovations on career choice and clinical care as well as other information that could be useful in devising a more transparent and equitable system of support for GME.THCGME program advocates should, however, be cautious in applying any lessons learned to broader GME policy reform. Unlike the THCGME funding, Medicare GME payments are part of the Medicare entitlement, tied to provision of clinical services and financed outside the annual congressional appropriations process. Pressure on domestic discretionary spending makes substantially expanded appropriations for the THCGME program an unlikely path for widespread reform. Absent secure "all-payer financing" of GME, residency program sponsors lack sufficient Medicare funds to cover all GME costs and must favor investments in specialties that meet local concerns, not long-term national workforce priorities. Nonetheless, the THCGME program provides an exciting opportunity to improve and to study primary care GME. Furthermore, the organizational infrastructures established, program leaders developed, data collected, and lessons learned from the program can inform more fundamental change in U.S. GME payment policy.
Convective and Rotational Stability of a Dilute Plasma

The stability of a dilute plasma to local convective and rotational disturbances is examined. A subthermal magnetic field and finite thermal conductivity along the field lines are included in the analysis. Stability criteria similar in form to the classical Hoiland inequalities are found, but with angular velocity gradients replacing angular momentum gradients, and temperature gradients replacing entropy gradients. These criteria are indifferent to the properties of the magnetic field and to the magnitude of the thermal conductivity. Angular velocity gradients and temperature gradients are both free energy sources; it is not surprising that they are directly relevant to the stability of the gas. Magnetic fields and thermal conductivity provide the means by which these sources can be tapped. Previous studies have generally been based upon the classical Hoiland criteria, which are inappropriate for magnetized, dilute astrophysical plasmas. In sharp contrast to recent claims in the literature, the new stability criteria demonstrate that marginal flow stability is not a fundamental property of accreting plasmas thought to be associated with low-luminosity X-ray sources.
Sexual attitudes and behavior of young adults who were burned as children.

Abstract Objective Little is known about sexual attitudes and behaviors of adults burned as children. We hypothesized that survivors with large burn scars would have differences in sexual attitudes and behaviors from their unburned counterparts. Methods Ninety-two young adults (50 males and 42 females), ages 21.0 ± 2.7 years old, who were burned 30% total body surface area or more as children 14.2 ± 5.4 years earlier, completed the questionnaire “What Young People Believe and Do” by RC Sorenson, 1972. The questionnaire explores sources of sexual information, attitudes toward different sexual behaviors, and experience with different sexual behaviors. Results Sixty-five percent of the females and 52% of the males currently had a significant other. Although only 54% women and 60% of men felt they were sexually attractive, 83 and 87%, respectively, endorsed feeling confident about sex. Experience with sexual intercourse was common: 90% of females and 76% of males. Burn severity was not significantly correlated with sexual attitudes and behaviors. Conclusion The majority of 92 young adults burned as children described sexual attitudes and behaviors comparable to the general population and the vast majority had significant sexual experience. Females reported more sexual behavior post-burn than males.
Local anisotropy in globally isotropic granular packings.

We report on two-dimensional computer simulations of frictionless granular packings at various area fractions φ above the jamming point φ(c). We measure the anisotropy in coarse-grained stress e(s) and shear modulus e(m) as functions of coarse-graining scale, R. e(s) can be collapsed onto a master curve after rescaling R by a characteristic length scale ξ and e(s) by an anisotropy magnitude A. Both A and ξ accelerate as φ→φ(c) from above, consistent with a divergence at φ(c). e(m) shows no characteristic length scale and has a nontrivial power-law form, e(m)~R(-0.62), over almost the entire range of R at all φ. These results suggest that the force chains present in the spatial structure of the quenched stress may be governed by different physics than the anomalous elastic response near jamming.
Is this a good title

Missing web pages, URIs that return the 404 "Page Not Found" error or the HTTP response code 200 but dereference unexpected content, are ubiquitous in today's browsing experience. We use Internet search engines to relocate such missing pages and provide means that help automate the rediscovery process. We propose querying web pages' titles against search engines. We investigate the retrieval performance of titles and compare them to lexical signatures which are derived from the pages' content. Since titles naturally represent the content of a document they intuitively change over time. We measure the edit distance between current titles and titles of copies of the same pages obtained from the Internet Archive and display their evolution. We further investigate the correlation between title changes and content modifications of a web page over time. Lastly we provide a predictive model for the quality of any given web page title in terms of its discovery performance. Our results show that titles return more than 60% URIs top ranked and further relevant content returned in the top 10 results. We show that titles decay slowly but are far more stable than the pages' content. We further distill stop titles than can help identify insufficiently performing search engine queries.
Domain-oriented design environments

The field of knowledge-based software engineering has been undergoing a shift in emphasis from automatic programming to human augmentation and empowerment. In our research work, we support this shift with an approach that embedshuman-computer cooperative problem-solving tools intodomain-oriented, knowledge-based design environments. Domain orientation reduces the large conceptual distance between problem-domain semantics and software artifacts. Integrated environments support the coevolution of specification and construction while allowing designers to access relevant knowledge at each stage within the software development process.
THE COMPLEMENTARY UNBOUNDEDNESS OF DUAL FEASIBLE SOLUTION SETS IN CONVEX PROGRAMMING

F.E. Clark has shown that if at least one of the feasible solution sets for a pair of dual linear programming problems is nonempty then at least one of them is both nonempty and unbounded. Subsequently, M. Avriel and A.C. Williams have obtained the same result in the more general context of (prototype posynomial) geometric programming. In this paper we show that the same result is actually false in the even more general context of convex programming — unless a certain regularity condition is satisfied.
The Seiberg-Witten differential from M theory

Abstract The form of the Seiberg-Witten differential is derived from the M-theory approach to N = 2 supersymmetric Yang-Mills theories by directly imposing the BPS condition for twobranes ending on fivebranes. The BPS condition also implies that the pullback of the Kahler form onto the space part of the twobrane world-volume vanishes.
A rate-compatible sphere-packing analysis of feedback coding with limited retransmissions

Recent work by Polyanskiy et al. and Chen et al. has excited new interest in using feedback to approach capacity with low latency. Polyanskiy showed that feedback identifying the first symbol at which decoding is successful allows capacity to be approached with surprisingly low latency. This paper uses Chen's rate-compatible sphere-packing (RCSP) analysis to study what happens when symbols must be transmitted in packets, as with a traditional hybrid ARQ system, and limited to relatively few (six or fewer) incremental transmissions. Numerical optimizations find the series of progressively growing cumulative block lengths that enable RCSP to approach capacity with the minimum possible latency. RCSP analysis shows that five incremental transmissions are sufficient to achieve 92% of capacity with an average block length of fewer than 101 symbols on the AWGN channel with SNR of 2.0 dB. The RCSP analysis provides a decoding error trajectory that specifies the decoding error rate for each cumulative block length. Though RCSP is an idealization, an example tail-biting convolutional code matches the RCSP decoding error trajectory and achieves 91% of capacity with an average block length of 102 symbols on the AWGN channel with SNR of 2.0 dB. We also show how RCSP analysis can be used in cases where packets have deadlines associated with them (leading to an outage probability).