cssi/SciSciGPT-SciSciNet huggingface dataset:
Some new embeddings and nonimmersions of real projective spaces

We obtain new families of embeddings and nonimmersions of real projective spaces in Euclidean space. The method involves obstruction theory, and includes several new insights. 1. STATEMENT OF RESULTS In this paper, we obtain the following new results regarding immersions and embeddings of real projective space pm in Euclidean space. Let a(n) denote the number of l's in the binary expansion of n. Theorem 1.1. If a(n) = 2, then (1) pl6n+8 cannot be immersed in R32n+3, and (2) pl6n+10 cannot be immersed in R32n+ll. Theorem 1.2. If a(n) > 2, then p8n+4 can be embedded in Rl6n+l. Theorem 1.1(1) improves on the previously best known result ([1]) by 1 dimension, while Theorem 1.1(2) improves on the previously best known nonimmersion and nonembedding results ([2]) for pl6n+10 and pl6n+1l by 4 dimensions, and is within 1 of best possible for them. It also implies new nonimmersions for pl6n+12, pl6n+13, and pl6n+14. Theorem 1.2 improves on the previously best known embedding ([11]) of p8nf+4 by 1 dimension. These results can best be appreciated when viewed in a table of known embedding and immersion results for real projective spaces. Such a table may be seen on the internet (see [3]). The method of proof is obstruction theory, specifically modified Postnikov towers (MPTs). The reason that Theorem 1.1 had not been noticed before is that the first author used to think that nonimmersions were extremely difficult to prove by MPTs because of the possibility of secondary and higher order indeterminacy. We show here that sometimes there is no secondary or higher order indeterminacy for a simple reason. The reason that Theorem 1.2 had not been noticed before is that this was apparently the first time that Mahowald's inductive approach to constructing embeddings ([8]) was combined with the method of evaluation of obstructions initiated in [5]. Received by the editors February 12, 1999. 1991 Mathematics Subject Classification. Primary 57R40.
Learning about intervention target zones

Abstract This paper provides a framework for evaluating how market participants beliefs about foreign exchange target zones change as they learn about central bank intervention policy. We generalize the standard target-zone model to allow for intra-marginal intervention. Intra-marginal intervention implies that market participants' beliefs about the target zone can be determined from their beliefs about the likelihood of intervention. We then estimate a daily probability of intervention model for the period following the Louvre Accord. We find that the market's views of intervention target zones would have varied quite a bit over time even over this relatively stable period.
AN ADVANCING TIME HYPOTHESIS

The evolution of the universe is described as an advancement of time, and only collaterally an expansion of space. An interpretation of time as proceeding at the equivalent of c across space, perpendicular to space, per a reconsideration of Minkowski’s space-time geometry, supports a description of the cosmos as a four-dimensional (hyper) spherical wavefront. By treating space as the surface of a four-dimensional sphere with a current radius of 13.82 billion years (equal to 13.82 billion light years), a Hubble constant of 70.6 (km/s) /Mpc is derived from the measure of the expansion of a megaparsec arc on the surface, independent of empirical measurement or mathematical inversion. It is argued that a close correlation between the advancing temporal cosmic radius and the expansion of the arc subtending a Mpc suggests at least a remarkable coincidence, worthy of further investigation. The hypothesis also has the scientific virtue of economy of explanation, dispensing with the need for the (revived) cosmological constant, cosmic inflation, dark energy, and dark matter as a gravitational constraint on expansion, as well as questions about the shape of the universe and of the influence of gravitation on the rate of expansion. A reexamination of various cosmological parameters in terms of an advancing time hypothesis is expected to provide further confirmation and confer greater simplicity and general coherence to cosmology.
Nature and origins of virtual environments: a bibliographical essay

—Virtual environments presented via head-mounted, computer-driven displays provide a new media for communication. They may be analyzed by considering: (1) what may be meant by an environment; (2) what is meant by the process of virtualization; and (3) some aspects of human performance that constrain environmental design. Their origins are traced from previous work in vehicle simulation and multimedia research. Pointers are provided to key technical references, in the dispersed, archival literature, that are relevant to the development and evaluation of virtual-environment interface systems.
Near optimal leader election in multi-hop radio networks

We design leader election protocols for multi-hop radio networks that elect a leader in almost the same time TBC that it takes for broadcasting one message (one ID). For the setting without collision detection our algorithm runs whp. in O(D log n/D + log3n) · min{log log n, log n/D} rounds on any n-node network with diameter D. Since TBC = Θ(D log n/D + log2n) is a lower bound, our upper bound is optimal up to a factor of at most log log n and the extra log n factor on the additive term. Our algorithm is furthermore the first O(n) time algorithm for this setting.Our algorithm improves over a 23 year old simulation approach of Bar-Yehuda, Goldreich and Itai with a O(TBC log n) running time: In 1987 they designed a fast broadcast protocol and subsequently in 1989 they showed how it can be used to simulate one round of a single-hop network that has collision detection in TBC time. The prime application of this simulation was to simulate Willards single-hop leader election protocol, which elects a leader in O(log n) rounds whp. and O(log log n) rounds in expectation. While it was subsequently shown that Willards bounds are tight, it was unclear whether the simulation approach is optimal. Our results break this barrier and essentially remove the logarithmic slowdown over the broadcast time TBC. This is achieved by going away from the simulation approach.We also give an O(D + log n log log n) · min{log log n, log n/D} = O(D + log n) · O(log log n)2 leader election algorithm for the setting with collision detection (even with single-bit messages). This is optimal up to log log n factors and improves over a deterministic algorithm that requires Θ(n) rounds independently of D.Our almost optimal leader election protocols are especially important because countless communication protocols in radio networks use leader election as a crucial first step to solve various, seemingly unrelated, communication primitives such as gathering, multiple unicasts or multiple broadcasts. Even though leader election seems easier than these tasks, its best-known O(TBC log n) running time had become a bottleneck, preventing optimal algorithms. Breaking the simulation barrier for leader election in this paper has subsequently led to the development of near optimal protocols for these communication primitives.
Agricultural factor markets in Sub-Saharan Africa: An updated view with formal tests for market failure.

This paper uses the recently collected Living Standard Measurement Study-Integrated Surveys on Agriculture Initiative data sets from five countries in Sub-Saharan Africa to provide a comprehensive overview of land and labor market participation by agrarian households and to formally test for failures in factor markets. Under complete and competitive markets, households can solve their consumption and production problems separately, so that household factor endowments do not predict input demand. This paper implements a simple, theoretically grounded test of this separation hypothesis, which can be interpreted as a reduced form test of factor market failure. In all five study countries, the analysis finds strong evidence of factor market failure. Moreover, those failures appear general and structural, not specific to subpopulations defined by gender or geography.
Homological Perturbation Theory for Nonperturbative Integrals

We use the homological perturbation lemma to produce explicit formulas computing the class in the twisted de Rham complex represented by an arbitrary polynomial. This is a non-asymptotic version of the method of Feynman diagrams. In particular, we explain that phenomena usually thought of as particular to asymptotic integrals in fact also occur exactly: integrals of the type appearing in quantum field theory can be reduced in a totally algebraic fashion to integrals over an Euler–Lagrange locus, provided this locus is understood in the scheme-theoretic sense, so that imaginary critical points and multiplicities of degenerate critical points contribute.
BV Concentric Aperture Photometry of Globular Clusters

Globular clusters are among the most difficult types of objects to observe with standard photoelectric techniques. Among factors which may contribute to measurement error are the centering of apertures in the oftentimes diffuse cores of clusters, the random distribution of bright stars near the cluster centers, and the determination of an adequate sky correction in fields badly crowded by foreground stars. These problems have been well-discussed by a number of authors (see, e.g., Hanes and Brodie 1984, and the references they cite).
The Iron Project and the RmaX Project

Ongoing activities under an international collaboration of atomic physicists and astrophysicists under the Iron Project and the RmaX Project, with applications to X-ray astronomy, are briefly described.
Observations of Low-Degree P-Mode Oscillations In 1984

Analysis of Stanford differential velocity observations has been extended through the 1984 observing season. Excellent quality observations were obtained in 1984 on 38 days in a 49 day interval from June 20th through August 7th. The power spectrum of this data has been examined and improved frequency determinations have been made for p-modes of degree 2 through 5 and order 5 through 34. Of special interest are the modes of the lower orders, n ranging from 5 to 10, which have not been identified previously.
Testing the Hypothesis That Charge Exchange Can Cause a Two‐Phase Decay

We test the hypothesis that a two-phase decay of the ring current energy content can be produced by the differential charge exchange loss rates of hot O + and hot H + . Results are presented from idealized simulations of ring current decay and show that, for realistic plasma boundary conditions, a two-phase decay can only be created by the transition from flow-out to charge exchange dominance of ring current loss. Differential charge exchange between hot (E > 40 keV) O + and hot H + cannot produce the observed two-phase decay signature for several reasons. First, there are always significant levels of low-energy (E < 10 keV) IT present in the injected plasma, which charge exchanges rapidly and makes the H + loss rate comparable to or greater than the O + loss rate. Second, the ring current is spread over a wide range of L values, and the total charge exchange loss rate is an integral value that does not suddenly change. Third, this integral loss rate is too slow (at least in the results presented here) to create a rapid loss of ring current energy content. Other possible causes of two-phase decay signatures in the storm-time Dst index are briefly discussed.
Magnetism of thin film multilayers: An analogue of interacting platelets

Progress is being made toward manufacturing materials with magnetic properties tailored to the desired application. This result is reached in several steps, which are monitored with different optical techniques such as polarized neutron reflectometry. First, ferromagnetic, metallic films (of Fe, Co, Ni, Gd), a few nanometers thick, are prepared by vapor deposition. Their magnetization can be tuned by changing the chemistry or thickness of the films, and can be biased by embedding the films into a matrix of antiferromagnetic material. Ensembles of metallic films (multilayers or superlattices) can be created, with a magnetic coupling between adjacent layers regulated by the nature and thickness of the spacer. For increasing spacer thickness, the alignment of neighboring magnetic layers switches between a parallel (F) and an opposite arrangement (AF) in an oscillatory manner. In multilayer structures possessing more than one kind of magnetic atom complex magnetic phase diagrams have been predicted to occur, with properties that are strongly influenced by the presence of a surface. With these characteristics, the phenomenology of magnetic multilayers draws a close similarity to the physics of interacting platelets.
Solar and Supernova Constraints on Cosmologically Interesting Neutrinos

The sun and core-collapse supernovae produce neutrino spectra that are sensitive to the effects of masses and mixing. Current results from solar neutrino experiments provide perhaps our best evidence for such new neutrino physics, beyond the standard electroweak model. I discuss this evidence as well as the limited possibilities for more conventional explanations. If the resolution of the solar neutrino problem is v e → v µ oscillations, standard seesaw estimates of m u τ , suggest a cosmologically interesting third-generation neutrino. I discuss recent nucleosynthesis arguments that lead to an important constraint on this possibility.
Guidance and Control for Mars Atmospheric Entry: Adaptivity and Robustness

In this paper, we address the atmospheric entry guidance and control problem for Mars precision landing. The guidance and control design is based on the principle of tracking a reference drag versus velocity profile in the entry flight corridor, which is determined by physical constraints of the flight. An integrated adaptive/robust control approach to atmospheric entry guidance and control is introduced to deal with different uncertainties.
Ion reflection, gyration, and dissipation at supercritical shocks

Topics on collisionless plasmas are discussed and include: (1) Ion reflection is the dominant ion dissipation mechanism at nearly perpendicular, supercritical shocks. (2) An increasing fraction of the ions incident on a supercritical shock is reflected as the Mach number increases. The actual fraction reflected can be predicted using the Rankine Hugoniot conservation relations. (3) The effective temperature associated with the dispersion in velocity space associated with ion reflection accounts for a large fraction of the temperature rise observed across supercritical, quasi perpendicular shocks.
Quantum robots plus environments.

A quantum robot is a mobile quantum system, including an on board quantum computer and needed ancillary systems, that interacts with an environment of quantum systems. Quantum robots carry out tasks whose goals include making specified changes in the state of the environment or carrying out measurements on the environment. The environments considered so far, oracles, data bases, and quantum registers, are seen to be special cases of environments considered here. It is also seen that a quantum robot should include a quantum computer and cannot be simply a multistate head. A model of quantum robots and their interactions is discussed in which each task, as a sequence of alternating computation and action phases,is described by a unitary single time step operator T {approx} T{sub a} + T{sub c} (discrete space and time are assumed). The overall system dynamics is described as a sum over paths of completed computation (T{sub c}) and action (T{sub a}) phases. A simple example of a task, measuring the distance between the quantum robot and a particle on a 1D lattice with quantum phase path dispersion present, is analyzed. A decision diagram for the task is presented and analyzed.
Some New Results in Theoretical Cosmology

After a general introduction to the standard Friedman models we discuss the topology of the big bang and the horizon structure of inflationary universes.
Simple recursion relations for general field theories

On-shell methods offer an alternative definition of quantum field theory at tree-level, replacing Feynman diagrams with recursion relations and interaction vertices with a handful of seed scattering amplitudes. In this paper we determine the simplest recursion relations needed to construct a general four-dimensional quantum field theory of massless particles. For this purpose we define a covering space of recursion relations which naturally generalizes all existing constructions, including those of BCFW and Risager. The validity of each recursion relation hinges on the large momentum behavior of an n-point scattering amplitude under an m-line momentum shift, which we determine solely from dimensional analysis, Lorentz invariance, and locality. We show that all amplitudes in a renormalizable theory are 5-line constructible. Amplitudes are 3-line constructible if an external particle carries spin or if the scalars in the theory carry equal charge under a global or gauge symmetry. Remarkably, this implies the 3-line constructibility of all gauge theories with fermions and complex scalars in arbitrary representations, all supersymmetric theories, and the standard model. Moreover, all amplitudes in non-renormalizable theories without derivative interactions are constructible; with derivative interactions, a subset of amplitudes is constructible. We illustrate our results with examples from both renormalizable and non-renormalizable theories. Our study demonstrates both the power and limitations of recursion relations as a self-contained formulation of quantum field theory.
Convective injection into stratospheric intrusions

[1] Stratospheric intrusions (tropopause folds) are known to be major contributors to stratosphere-troposphere exchange. The specific mixing processes that lead to irreversible exchange between stratospheric intrusions and the surrounding troposphere, however, are not entirely understood. This study presents direct observations of moist convection penetrating into stratospheric intrusions. The characteristics of convective injection are shown by using in situ aircraft measurements, radar reflectivities, and model analyses. Convective injection is observed at altitudes up to 5 km above the bottom of a stratospheric intrusion. Aircraft measurements from the Stratosphere-Troposphere Analyses of Regional Transport 2008 (START08) experiment show that convective injection in stratospheric intrusions can be uniquely identified by coincident observations of water vapor greater than about 100 ppmv and ozone greater than about 125 ppbv. Trajectory analyses show that convective injection can impact transport in both directions: from troposphere to stratosphere and from stratosphere to troposphere. We present a conceptual model of the synoptic meteorological conditions conducive to convective injection in stratospheric intrusions. In particular, convective injection is found to be associated with a “split front” where the upper-level frontal boundary outruns the surface cold front.
Keck Spectroscopy and NICMOS Photometry of a Redshift z = 5.60 Galaxy*

We present Keck Low Resolution Imaging Spectrometer spectroscopy along with Near-Infrared Camera and Multiobject Spectrometer (NICMOS) F110W (~J) and F160W (~H) images of the galaxy HDF 4-473.0 in the Hubble Deep Field (HDF), with a detection of an emission line consistent with Lyα at a redshift of z=5.60. Attention to this object as a high-redshift galaxy was first drawn by Lanzetta, Yahil, & Fernandez-Soto and appeared in their initial list of galaxies with redshifts estimated from the Wide Field Planetary Camera 2 (WFPC2) HDF photometry. It was selected by us for spectroscopic observation, along with others in the HDF, on the basis of the NICMOS F110W and F160W and WFPC2 photometry. For H_0=65 km s^(-1) Mpc^(-1) and q_0=0.125, the use of simple evolutionary models along with the F814W (~I), F110W, and F160W magnitudes allow us to estimate the star formation rate (~13 M_☉ yr^(-1)). The colors suggest a reddening of E(B-V)~0.06. The measured flux in the Lyα line is approximately 1.0×10^(−17) ergs cm^(-2) s^(-1), and the rest-frame equivalent width, correcting for the absorption caused by intervening H I, is ~90 A. The galaxy is compact and regular, but resolved, with an observed FWHM of ~0."44. Simple evolutionary models can accurately reproduce the colors, and these models predict the Lyα flux to within a factor of 2. Using this object as a template shifted to higher redshifts, we calculate the magnitudes through the F814W and two NICMOS passbands for galaxies at redshifts 6<z<10.
Causal inference and causal explanation with background knowledge

This paper presents correct algorithms for answering the following two questions; (i) Does there exist a causal explanation consistent with a set of background knowledge which explains all of the observed independence facts in a sample? (ii) Given that there is such a causal explanation what are the causal relationships common to every such causal explanation?
A Rejection Principle for Sequential Tests of Multiple Hypotheses Controlling Familywise Error Rates

We present a unifying approach to multiple testing procedures for sequential (or streaming) data by giving sufficient conditions for a sequential multiple testing procedure to control the familywise error rate (FWER). Together we call these conditions a "rejection principle for sequential tests," which we then apply to some existing sequential multiple testing procedures to give simplified understanding of their FWER control. Next the principle is applied to derive two new sequential multiple testing procedures with provable FWER control, one for testing hypotheses in order and another for closed testing. Examples of these new procedures are given by applying them to a chromosome aberration data set and to finding the maximum safe dose of a treatment.
Risk Management for Event-Driven Funds

Many portfolio strategies are “event driven” (i.e., designed to benefit from price movements caused by corporate events, such as a merger). These strategies involve payoffs with discontinuous and skewed distributions that conventional risk methods do not measure well. This article develops methods to measure the forward-looking risk, based on current positions, of portfolios exposed to such discrete events. The method is applied to independent events and to the more realistic case of events that are not independent. For mergers and acquisitions, empirical estimates of deal-break correlations are positive but low, which implies that most of this event risk is idiosyncratic and diversifiable. The methodology allows assessment of the risk and return of various portfolio structures for event-driven funds.
Too poor to grow

Recent theoretical literature has suggested a variety of mechanisms through which poverty may deter growth and become self-perpetuating. A few papers have searched for empirical regularities consistent with those mechanisms  such as aggregate non-convexities and convergence clubs. However, a seemingly basic implication of the theoretical models, namely that countries suffering from higher levels of poverty should grow less rapidly, has remained untested. This paper attempts to fill that gap and provide a direct empirical assessment of the impact of poverty on growth. The papers strategy involves including poverty indicators among the explanatory variables in an otherwise standard empirical growth equation. Using a large panel dataset, the authors find that poverty has a negative impact on growth that is significant both statistically and economically. This result is robust to a variety of specification changes, including (i) different poverty lines; (ii) different poverty measures; (iii) different sets of control variables; (iv) different estimation methods; (v) adding inequality as a control variable; and (vi) allowing for nonlinear effects of inequality on growth. The paper also finds evidence that the adverse effect of poverty on growth works through investment: high poverty deters investment, which in turn lowers growth. Further, the data suggest that this mechanism only operates at low levels of financial development, consistent with the predictions of theoretical models that underscore financial market imperfections as a key ingredient of poverty traps.
Straightforward Access to Hexahydropyrrolo[2,3- b]indole Core by a Regioselective C3-Azo Coupling Reaction of Arenediazonium Compounds with Tryptamines

A base-mediated regioselective electrophilic addition of arenediazonium salts at the C3-position of tryptamines followed by cyclization provides an efficient entry to C3-nitrogenated hexahydropyrrolo[2,3-b]indoles (HPIs) that can subsequently be transformed into 3-arylhexahydropyrrolo[2,3-b]indoles and other HPI derivatives. The reaction is the first example of a 1,2-diamination that utilizes easily accessible arenediazonium salts as nitrogenous electrophiles.
Power market structure and performance

Unbundling power generation, transmission, and distribution is not an end itself, but rather a means to achieve better performance. The key objective of the analytical framework of this paper is to explore the links between alternative market structures and performance (in terms of access, price, quality, and technical and financial performance). The results are crucial for providing policy advice, by offering alternative options to policy makers based on the lessons learned from the taxonomy of different market structures, tailored to different national contexts. The analysis is based on unique data, including a panel of 22 countries for the period beginning in 1989 and extending through 2009. The results of the analysis carried out for this study confirm the following conclusions for policy guidance on power market restructuring for developing countries. First, unbundling delivers results in terms of several performance indicators when used as an entry point to implement broader reforms, particularly introducing a sound regulatory framework, reducing the degree of concentration of the generation and distribution segments of the market by attracting public and private players and private sector participation. Second, there seems to be a credible empirical basis for selecting a threshold power system size and per capita income level below which unbundling of the power supply chain is not expected to be worthwhile. Finally, partial forms of vertical unbundling do not appear to drive improvements, probably because the owner was able to continue exercising control over the affairs of the sector and hinder the development of competitive pressure within the power market.
Dynamic pagerank using evolving teleportation

The importance of nodes in a network constantly fluctuates based on changes in the network structure as well as changes in external interest. We propose an evolving teleportation adaptation of the PageRank method to capture how changes in external interest influence the importance of a node. This framework seamlessly generalizes PageRank because the importance of a node will converge to the PageRank values if the external influence stops changing. We demonstrate the effectiveness of the evolving teleportation on the Wikipedia graph and the Twitter social network. The external interest is given by the number of hourly visitors to each page and the number of monthly tweets for each user.
“To Share or not to Share” in Client-Side Encrypted Clouds

With the advent of cloud computing, a number of cloud providers have arisen to provide Storage-as-a-Service (SaaS) offerings to both regular consumers and business organizations. SaaS (different than Software-as-a-Service in this context) refers to an architectural model in which a cloud provider provides digital storage on their own infrastructure. Three models exist amongst SaaS providers for protecting the confidentiality of data stored in the cloud: 1) no encryption (data is stored in plain text), 2) server-side encryption (data is encrypted once uploaded), and 3) client-side encryption (data is encrypted prior to upload). Through a combination of a Network and Source Code Analysis, this paper seeks to identify weaknesses in the third model, as it claims to offer 100% user data confidentiality throughout all data transactions. The weaknesses we uncovered primarily center around the fact that the cloud providers we evaluated (Wuala, Tresorit, and Spider Oak) were each operating in a Certificate Authority capacity to facilitate data sharing. In this capacity, they assume the role of both certificate issuer and certificate authorizer as denoted in a Public-Key Infrastructure (PKI) scheme - which gives them the ability to view user data contradicting their claims of 100% data confidentiality. We have collated our analysis and findings in this paper and explore some potential solutions to address these weaknesses in these sharing methods. The solutions proposed are a combination of best practices associated with the use of PKI and other cryptographic primitives generally accepted for protecting the confidentiality of shared information.
Identity-Based Proxy Re-encryption

In a proxy re-encryption scheme a semi-trusted proxy converts a ciphertext for Alice into a ciphertext for Bob without seeing the underlying plaintext. A number of solutions have been proposed in the public-key setting. In this paper, we address the problem of Identity-Based proxy re-encryption, where ciphertexts are transformed from one identityto another. Our schemes are compatible with current IBE deployments and do not require any extra work from the IBE trusted-party key generator. In addition, they are non-interactive and one of them permits multiple re-encryptions. Their security is based on a standard assumption (DBDH) in the random oracle model.
Uncertainty, instability, and irreversible investment : theory, evidence, and lessons for Africa

A recent (but rapidly growing) literature has focused on how uncertainty and instability affect the adoption of fixed investment projects. That literature shows that if fixed investment projects are costly or impossible to reverse, uncertainty can become a powerful deterrent to investment. The author reviews the literature on irreversible investment to identify the implications for macroeconomic policy and to gauge the practical importance, especially for sub-Saharan Africa, of the link between uncertainty and investment. He presents empirical evidence on the negative association between investment performance and measures of instability, using cross-section time-series data. That evidence suggests that instability and uncertainty are important factors in Africa's poor investment record over the last two decades.
The Problem with Remaining Silent: Exemplification Effects and Public Image

A news report on the use of Lean Finley Textured Beef (LFTB) was created in order to examine the effects of exemplars. Respondents read a news story with exemplars about Lean Finely Textured Beef, a story with exemplars about LFTB followed by a factual government blog, or a factual government blog and then the story with exemplars. Respondents reported their perceptions of severity, susceptibility, and behavioral intentions. Outcomes were found to be highest for the exemplar-only condition and lowest for the blog followed by the story with exemplar. Results are discussed in terms of implications for public relations and risk communication.
Till geography do us part ? prolegomena to an economic and monetary union between the Dominican Republic and Haiti

This paper offers a preliminary assessment of the potential benefits and costs of an economic and monetary union (EMU) between the Dominican Republic and Haiti -- two countries sharing the same island but whose history is one of conflict and divergent economic prospects in recent decades. After a brief review of the historical context, it examines the nature of these potential benefits and costs. It then conducts a preliminary analysis (using basic statistical techniques) of some key criteria for the formation of an economic and monetary union between the two countries. A more formal analysis of business cycle synchronization, based on basic and extended integrated vector auto-regression models with exogenous variables (VARX), is developed next. Overall, the analysis suggests that at this stage several economic criteria are not satisfied for the two countries to fully benefit from an economic and monetary union. At the same time, however, the endogeneity of most of these criteria (including the degree of business cycle synchronization) militates in favor of an aggressive medium-term agenda for integration between them.
Energy and emissions : local and global effects of the rise of China and India

Part 1 of the paper reviews recent trends in fossil fuel use and associated externalities. It also argues that the recent run-up in international oil prices reflects growing concerns about supply constraints associated with declining spare capacity in OPEC, refining bottlenecks, and geopolitical uncertainties rather than growing incremental use of oil by China and India. Part 2 compares two business as usual scenarios with a set of alternate scenarios based on policy interventions on the demand for or supply of energy and different assumptions about rigidities in domestic and international energy markets. The results suggest that energy externalities are likely to worsen significantly if there is no shift in China's and India's energy strategies. High energy demand from China and India could constrain some developing countries' growth through higher prices on international energy markets, but for others the "growth retarding" effects of higher energy prices are partially or fully offset by the "growth stimulating" effects of the larger markets in China and India. Given that there are many inefficiencies in the energy system in both China and India, there is an opportunity to reduce energy growth without adversely affecting GDP growth. The cost of a decarbonizing energy strategy will be higher for China and India than a fossil fuel-based strategy, but the net present value of delaying the shift will be higher than acting now. The less fossil fuel dependent alternative strategies provide additional dividends in terms of energy security.
Diffusions on graphs, Poisson problems and spectral geometry

We study diffusions, variational principles and associated boundary value problems on directed graphs with natural weightings. We associate to certain subgraphs (domains) a pair of sequences, each of which is invariant under the action of the automorphism group of the underlying graph. We prove that these invariants differ by an explicit combinatorial factor given by Stirling numbers of the first and second kind. We prove that for any domain with a natural weighting, these invariants determine the eigenvalues of the Laplace operator corresponding to eigenvectors with nonzero mean. As a specific example, we investigate the relationship between our invariants and heat content asymptotics, expressing both as special values of an analog of a spectral zeta function.
Maternal-Fetal Medicine physicians' practice patterns for 22-week delivery management.

AbstractObjective: To describe Maternal-Fetal Medicine (MFM) physicians’ practice patterns for 22-week delivery management.Mehods: Surveyed 750 randomly-sampled members of the Society of Maternal-Fetal Medicine, querying MFMs’ practices and policies guiding 22-week delivery management.Results: Three hundred and twenty-five (43%) MFMs responded. Nearly all (87%) would offer induction. Twenty-eight percent would order steroids, and 12% would perform cesarean for a patient desiring resuscitation. Offering induction differed significantly based on the provider’s practice setting, region, religious service attendance and political affiliation. In multivariable analyses, political affiliation remained a significant predictor of offering induction (p = 0.03).Conclusions: Most MFMs offer induction for PPROM at 22 weeks. A noteworthy proportion is willing to order steroids and perform cesarean. Personal beliefs and practice characteristics may contribute to these decisions. While little is known about the efficacy...
The local bubble, local fluff, and heliosphere

The properties of the Local Bubble, Local Fluff complex of nearby interstellar clouds, and the heliosphere are mutually constrained by data and theory. Observations and models of the diffuse radiation field, interstellar ionization, pick-up ion and anomalous cosmic-ray populations, and interstellar dust link the physics of these regions. The differences between the one-asymmetric-superbubble and two-superbubble views of the Local Bubble are discussed.
Magnons in the Ferromagnetic Kondo‐Lattice Model

The magnetic properties of the ferromagnetic Kondo-lattice model (FKLM) are investigated. Starting from an analysis of the magnon spectrum in the spin-wave regime, we examine the ferromagnetic stability as a function of the occupation of the conduction band n and the strength J of the coupling between the localised moments and the conduction electrons. From the properties of the spin-wave stiffness D the ferromagnetic phase at zero temperature is derived. Using an approximate formula the critical temperature T c is calculated as a function of J and n.
Are Education Cost Functions Ready for Prime Time? An Examination of Their Validity and Reliability

This article makes the case that cost functions are the best available methodology for ensuring consistency between a state's educational accountability system and its education finance system. Because they are based on historical data and well-known statistical methods, cost functions are a particularly flexible and low-cost way to forecast what each school district must spend to meet the standards in a state's accountability system. However, the application of cost functions to education must confront several challenges in both data collection and estimation methodology. This article describes the strengths and weaknesses of various ways to address these challenges and illustrates how the reliability and forecasting accuracy of cost functions can be tested using data for Missouri school districts.
Elliptic models and M-theory

Abstract We give a unified analysis of four-dimensional elliptic models with N =2 supersymmetry and a simple gauge group, and their relation to M-theory. Explicit calculations of the Seiberg–Witten curves and the resulting one-instanton prepotential are presented. The remarkable regularities that emerge are emphasized. In addition, we calculate the prepotential in the Coulomb phase of the (asymptotically-free) Sp (2 N ) gauge theory with N f fundamental hypermultiplets of arbitrary mass.
Adenoviral gene transfer of an NF-κB super-repressor increases collagen deposition in rodent cutaneous wound healing

Background The transcription factor nuclear factor-κB (NF-κB) plays an essential role in inflammation. To date, no studies have investigated the effect of inhibiting NF-κB–mediated inflammation on normal cutaneous wound healing. We tested this by locally administering an adenovirus recombinant that constitutively expresses a super-repressor isoform of inhibitory-κB (IκB) into rats undergoing a well-established model of dorsal wound healing. Methods Seventy-two Sprague-Dawley rats underwent insertion of a sponge-pump construct into a dorsal subcutaneous pocket. One group of rats received pumps filled with the adenovirus expressing I-κB (rAd-Iκb), a second group received pumps filled with adenovirus expressing green fluorescent protein (GFP) (rAd-gfp), and a third received pumps filled with normal saline (NS). Rats were killed in groups of 6 on days 1, 3, 5 and 7 postoperation. The wound fluid was analyzed for nitrite/nitrate (NOx) and tumor necrosis factor-alpha (TNF-α) concentrations. The wound fluid was assayed for hydroxyproline (OHP) content, an index of reparative collagen deposition. Results Administration of rAd-Iκb for 7 days resulted in higher collagen deposition (OHP) compared with the rAd-gfp and NS groups. NOx levels were significantly higher in the rAd-gfp group on day 1 and marginally so on day 5. TNF-α quantitation analysis found no significant difference among the 3 groups. Conclusion IκB expression through an adenoviral vector in the cutaneous wound may improve rodent healing, as shown by increased collagen deposition, through decreased inflammation. This mechanism appears to be TNF-α independent. Inhibition of NF-κB may reduce inflammation by reducing the local NOx concentrations.
Theoretical and Experimental Analysis of the Forced Response of Sagged Cable/Mass Suspensions

This study examines the forced response of a sagged elastic cable supporting an array of discrete masses. Such systems arise, for instance, in ocean engineering applications employing cable hydrophone arrays. The excitation considered is harmonic and normal to the cable and may, for instance, approximate prescribed environmental loading. An asymptotic model is presented that describes the linear forced response of a cable/mass suspension having small equilibrium curvature. Closed-form expressions for the Green’s function to an associated boundary value problem are obtained using a transfer matrix formulation. The derived Green’s function is utilized to construct integral representations for steady-state response under boundary and/or domain excitation. Solutions obtained for a variety of domain loading distributions demonstrate the utility and efficiency of this solution strategy. The theoretical response predictions are verified through experimental measurements of the natural frequency spectrum and frequency response of laboratory cable/mass suspensions.
COLLATERAL EFFECTS ON SOLAR NEBULA OXYGEN ISOTOPES DUE TO INJECTION OF 26Al BY A NEARBY SUPERNOVA

Injection of material from a core-collapse supernova into the solar system's already-formed disk is one proposed mechanism for producing the short-lived radionuclides, such as 26Al? and 41Ca, inferred from isotopic studies of meteorites to have existed in the solar nebula. This hypothesis has recently been challenged on the basis that the injection of enough supernova material to match the meteoritic abundances of 26Al and 41Ca would produce large, measurable, and unobserved collateral effects on oxygen isotopes. Here we calculate again the shifts in oxygen isotopes due to the injection of supernova material in the solar nebula, using a variety of nucleosynthetic conditions of our own progenitor explosions. Unlike previous studies of this type, we also consider the effect of non-homogeneity in abundance distribution of the nucleosynthesis products after the explosion. We calculate the shifts in oxygen isotopes due to the injection of sufficient supernova material to produce the meteoritic abundances of 26Al and 41Ca, and analyze the predicted shifts in detail for compatibility with meteoritic data. We find that the range in possible isotopic shifts is considerable and sensitive to parameters such as progenitor mass and anisotropy of the explosion; however, a small number of compatible scenarios do exist. Because of the wide range of outcomes and the sensitivity of isotopic yields to assumed conditions, it is difficult to constrain the supernova that may have led to the injection of 26Al in the solar nebula. Conversely, we argue that the existence of viable counterexamples demonstrates that it is premature to use oxygen isotopes to rule out the injection of 26Al and 41Ca into the solar nebula protoplanetary disk by a nearby supernova.
Eigensolution Reanalysis of Rotor Dynamic Systems by the Generalized Receptance Method

A method is presented for efficiently calculating the damped natural frequencies of complex rotor bearings systems. The procedure is applicable to the repeated reanalysis of rotor systems during the search for an optimal design. The generalized receptances used in the method are calculated with a series of formulas that improves the convergence characteristics when only an incomplete set of modes is available. A nonsynchronous gyroscopic rotor example is examined to illustrate the reanalysis procedure.Copyright © 1982 by ASME
Watching a Superfluid Untwist Itself: Recurrence of Rabi Oscillations in a Bose-Einstein Condensate

The order parameter of a condensate with two internal states can continuously distort in such a way as to remove twists that have been imposed along its length. We observe this effect experimentally in the collapse and recurrence of Rabi oscillations in a magnetically trapped, two-component Bose-Einstein condensate of ${}^{87}\mathrm{Rb}$.
ANALYSIS OF RANDOM REFERENCE TRACKING IN SYSTEMS WITH SATURATING ACTUATORS

Abstract This paper develops a method for analysis of random reference tracking in feedback systems with saturating actuators. The development is motivated by the frequency domain approach to linear systems, where the bandwidth and resonance peak of the sensitivity function are used to predict the quality of step reference tracking. Similarly based on the so-called saturating random sensitivity function, we introduce tracking quality indicators and show that they can be used to determine both the quality of random reference tracking and the nature of track loss under actuator saturation.
Structure, Optical Properties, and Magnetism of the Full Zn1–xCuxWO4 (0 ≤ x ≤ 1) Composition Range

Microcrystalline and submicrometer powders of Zn1–xCuxWO4 (0 ≤ x ≤ 1) have been prepared by a solid-state synthesis from stoichiometric quantities of the constituent d-block metal oxide and tungsten oxide as well as from a Pechini sol–gel synthesis starting from the d-block metal nitrate and ammonium metatungstate. The stoichiometry of the product is confirmed by inductively coupled plasma-atomic emission spectrometry (ICP-AES) analysis. X-ray diffraction shows that for the entire range of compositions, a single-phase product crystallizes in the wolframite structure, with a symmetry-lowering transition from P2/c to P1 at x = 0.20, concomitant with the first-order Jahn–Teller distortion of Cu2+. Far-IR spectroscopy corroborates that symmetry lowering is directly related to the tetragonal distortion within the CuO6 octahedra, with the Zn–O Au symmetry mode at 320 cm–1 (x = 0) splitting into two stretches at 295 and 338 cm–1 (x = 0.3). UV–vis–NIR spectroscopy shows an optical absorption edge characteristic ...
The product in the Hochschild cohomology ring of preprojective algebras of Dynkin quivers

Abstract In this paper, we compute the cup product structure of the preprojective algebra Dynkin quivers of type D and E over a field of characteristic zero. This is a continuation of the work done in [P. Etingof, C. Eu, Hochschild and cyclic homology of preprojective algebras of ADE quivers, arXiv: math.AG/0609006 ] where the additive structure of the Hochschild cohomology (together with its grading) was computed. Together with the results in [K. Erdmann, N. Snashall, On Hochschild cohomology of preprojective algebras. I, J. Algebra 205 (2) (1998) 391–412, II, J. Algebra 205 (2) (1998) 413–434] (where the A -case was studied), this yields a complete description of the product in the Hochschild cohomology of ADE quivers over a field of characteristic zero.
Nucleophilic aromatic substitution on 3-aroyl-2-arylbenzothiophenes. Rapid access to raloxifene and other selective estrogen receptor modulators

Abstract Versatile, mild and high yielding methods for nucleophilic aromatic substitution of 2-dialkylamino-1-ethoxides and related nucleophiles on 3-aroyl-2-arylbenzothiophene nuclei are presented. A short synthesis of raloxifene is detailed.
The first example of nickel-catalyzed silyl-Heck reactions: direct activation of silyl triflates without iodide additives

For the first time, nickel-catalyzed silyl-Heck reactions are reported. Using simple phosphine-supported nickel catalysts, direct activation of silyl triflates has been achieved. These results contrast earlier palladium-catalyzed systems, which require iodide additives to activate silyl-triflates. These nickel-based catalysts exhibit good functional group tolerance in the preparation of vinyl silanes, and unlike earlier systems, allows for the incorporation of trialkylsilanes larger than Me3Si.