cssi/SciSciGPT-SciSciNet huggingface dataset:
On generalized Whitehead products

We define a symmetric monodical pairing G ◦ H among simply connected co-H spaces G and H with the property that S(G◦H) is equivalent to the smash product G∧H as co-H spaces. We further generalize the Whitehead product map to a map G ◦ H → G ∨ H whose mapping cone is the cartesian product. Whitehead products have played an important role in unstable homotopy. They were originally introduced [Whi41] as a bilinear pairing of homotopy groups: πm(X)⊗ πn(X) → πm+n−1(X), m, n > 1. This was generalized ([Ark62], [Coh57], [Hil59]) by constructing a map W: S(A ∧B) → SA ∨ SB. Precomposition with W defines a function on based homotopy classes: [SA,X]× [SB,X] → [S(A ∧B), X], which is bilinear in case A and B are suspensions. The case where A and B are Moore spaces was central to the work of Cohen, Moore and Neisendorfer ([CMN79]). In [Ani93] and in particular [AG95], this work was generalized. Much of this has since been simplified in [GT10], but further understanding will require a generalization from suspensions to co-H spaces. The purpose of this work is to carry out and study such a generalization. Let CO be the category of simply connected co-H spaces and co-H maps. We define a functor CO × CO → CO, (G,H) → G ◦H, and a natural transformation (1) W: G ◦H → G ∨H generalizing the Whitehead product map. The existence of G◦H generalizes a result of Theriault [The03] who showed that the smash product of two simply connected co-associative co-H spaces is the suspension of a co-H space. We do not need the coH spaces to be co-associative and require only one of them to be simply connected. We call G ◦H the Theriault product of G and H. Received by the editors November 28, 2009 and, in revised form, June 8, 2010. 2010 Mathematics Subject Classification. Primary 55P99, 55Q15, 55Q20, 55Q25. 1In fact we can define G ◦ H for any two co-H spaces but require at least one of them to be either simply connected or a suspension in order to obtain the co-H space structure map on G◦H. Recently Grbic, Theriault and Wu have shown that the smash product of any two co-H spaces is the suspension of a co-H space, but their construction cannot satisfy Theorem 1(a) below [GTW]. c ©2011 American Mathematical Society Reverts to public domain 28 years from publication 6143
Thermodynamic aspects of the vitrification of toluene, and xylene isomers, and the fragility of liquid hydrocarbons

The three xylenes, 1,2‐, 1,3‐, and 1,4‐dimethyl benzene, provide a well‐characterized family of isomeric molecules within which the melting points vary greatly while fluid‐state properties such as boiling points and viscosities remain very similar. Because all pure isomers crystallize rapidly on cooling, their behavior at the low‐temperature end of the liquid state, i.e., near the glass transition, has not been studied. We report here differential scanning calorimetry studies of phase relations for the three mixed isomer systems, and identify composition regions in which emulsified and also bulk mixtures can be vitrified at ordinary cooling rates. For one of the latter, 70% m‐xylene+ 30% o‐xylene by volume, we determine the change in heat capacity through the glass transition. On the assumption that this is the same for pure m‐xylene, we assess the Kauzmann limit on liquid behavior, TK, for m‐xylene to fall at 104.6 K, Tg/TK to be 1.20, and the excess entropy at Tg to be 15.6 J/mol K or 30.5% of the entro...
Mixed Messages: Open‐Market Repurchases Following Stock Acquisitions

Management decisions and market reactions to those decisions do not occur in isolation. Despite this fact, little or no research has examined two events when they occur in a sequence, even when theory suggests that those two events convey opposite signals. We examine firms that do a stock-based acquisition then announce an open-market repurchase program. These two actions, according to the signaling theory, signal conflicting valuation errors. This paper is the first to examine a sequence of events that convey seemingly conflicting signals. Among other results, we find that repurchasers who had previously made a stock-based acquisition have a less positive market reaction than do otherwise comparable repurchasers with no previous acquisition. These results indicate that the market reactions to events are tempered by previous information-releasing events.
The Grothendieck Inequality Revisited

The classical Grothendieck inequality is viewed as a statement about representations of functions of two variables over discrete domains by integrals of two-fold products of functions of one variable. An analogous statement is proved, concerning continuous functions of two variables over general topological domains. The main result is the construction of a continuous map f from l2 (A) into L2 (O A, PA), where A is a set, OA = {-1,1}A, and PA is the uniform probability measure on OA.
HITTING TIMES AND INTERLACING EIGENVALUES: A STOCHASTIC APPROACH USING INTERTWININGS

We develop a systematic matrix-analytic approach, based on intertwinings of Markov semigroups, for proving theorems about hitting-time distributions for finite-state Markov chains—an approach that (sometimes) deepens understanding of the theorems by providing corresponding sample-path-by-sample-path stochastic constructions. We employ our approach to give new proofs and constructions for two theorems due to Mark Brown, theorems giving two quite different representations of hitting-time distributions for finite-state Markov chains started in stationarity. The proof, and corresponding construction, for one of the two theorems elucidates an intriguing connection between hitting-time distributions and the interlacing eigenvalues theorem for bordered symmetric matrices.
Warm-hot gas in and around the Milky Way: Detection and implications of OVII absorption toward LMC X-3

X-ray absorption lines of highly ionized species such as O VII at about zero redshift have been firmly detected in the spectra of several active galactic nuclei. However, the location of the absorbing gas remains a subject of debate. To separate the Galactic and extragalactic contributions to the absorption, we have obtained Chandra LETG-HRC and Far Ultraviolet Spectroscopic Explorer observations of the black hole X-ray binary LMC X-3. We clearly detect the O VII K? absorption line with an equivalent width of 20(14, 26) m??(90% confidence range). The Ne IX K? absorption line is also detected, albeit marginally. A joint analysis of these lines, together with the nondetection of the O VII K? and O VIII K? lines, gives the temperature, velocity dispersion, and hot oxygen column density as 1.3(0.7,1.8) ? 106 K, 79(62,132)?km?s-1, and 1.9(1.2, 3.2) ?1016?cm-2, assuming a collisional ionization equilibrium of the X-ray-absorbing gas and a Galactic interstellar Ne/O number ratio of 0.18. The X-ray data allow us to place a 95% confidence lower limit to the Ne/O ratio as 0.14, but the upper limit is not meaningfully constrained. The O VII line centroid and its relative shift from the Galactic O I K? absorption line, detected in the same observations, are inconsistent with the systemic velocity of LMC X-3 (+310?km?s-1). The far-UV spectrum shows O VI absorption at Galactic velocities, but no O VI absorption is detected at the LMC velocity at greater than 3 ? significance. The measured Galactic O VI column density is higher than the value predicted from the O VII-bearing gas, indicating multiphase absorption. Both the nonthermal broadening and the decreasing scale height with the increasing ionization state further suggest an origin of the highly ionized gas in a supernova-driven galactic fountain. In addition, we estimate the warm and hot electron column densities from our detected O II K? line in the LMC X-3 X-ray spectra and from the dispersion measure of a pulsar in the LMC vicinity. We then infer the O/H ratio of the gas to be 8 ? 10-5, consistent with the chemically enriched galactic fountain scenario. We conclude that the Galactic hot interstellar medium should in general substantially contribute to zero-redshift X-ray absorption lines in extragalactic sources.
The impact of dominant ownership: the case of Anglo-American firms

Ownership has been identified as a key mechanism in corporate governance. Agency theory suggests that high levels of ownership provide increased incentive for shareholders to monitor firm management which should lead to better firm performance. However, not every shareholder may have the same inclination and ability to act as an effective firm monitor. It is argued that the largest or dominant shareholder of a firm may have differing incentives to monitor their investment in the firm. This study examines the impact of three types of dominant shareholders on firm performance. Using a longitudinal sample of firms in the US and UK, findings show that firm performance is negatively influenced by CEO dominant owners. Furthermore, firms with dominant owners who have no existing business relationships with the firms have better firm performance than firms with dominant owners who have potential conflicts of interest. Thus, findings suggest that while dominant ownership creates the ability to monitor and influence firm management, the type of owner plays a large role in whether a shareholder has the inclination to engage in firm monitoring.
Stimulus Overselectivity in Typical Development: Implications for Teaching Children with Autism

Stimulus overselectivity is widely accepted as a stimulus control abnormality in autism spectrum disorders and subsets of other populations. Previous research has demonstrated a link between both chronological and mental age and overselectivity in typical development. However, the age at which children are developmentally ready to respond to discriminations involving simultaneous multiple cues has not been established. Thirty-seven typically developing preschoolers completed a task requiring response to simultaneous cues (color and shape) to establish the age at which typically developing children can successfully respond to multiple cues. Results demonstrate that typically developing children under 36 months of age have difficulty responding to multiple cues. Implications for behavioral treatment for autism are discussed.
Natural Language Processing

Natural language processing (NLP) is the study of mathematical and computational modeling of various aspects of language and the development of a wide range of systems. These include spoken language systems that integrate speech and natural language; cooperative interfaces to databases and knowledge bases that model aspects of human-human interaction; multilingual interfaces; machine translation; and message-understanding systems, among others. Research in NLP is highly interdisciplinary, involving concepts in computer science, linguistics, logic, and psychology. NLP has a special role in computer science because many aspects of the field deal with linguistic features of computation and NLP seeks to model language computationally.
A novel dicyanotriterpenoid, 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-onitrile, active at picomolar concentrations for inhibition of nitric oxide production.

New oleanane triterpenoids with various substituents at the C-17 position of 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid (CDDO) and methyl 2-carboxy-3,12-dioxooleana-1,9(11)-dien-28-oate were synthesized. Among them, 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-onitrile shows extremely high inhibitory activity (IC50=1 pM level) against production of nitric oxide induced by interferon-γ in mouse macrophages. This potency is about 100 times and 30 times more potent than CDDO and dexamethasone, respectively.
Optimizing restriction site placement for synthetic genomes

Restriction enzymes are the workhorses of molecular biology. We introduce a new problem which arises in the course of our project to design virus variants to serve as potential vaccines: we wish to modify virus-length genomes to introduce large numbers of unique restriction enzyme recognition sites while preserving wild-type function by substitution of synonymous codons. We show that the resulting problem is NP-Complete, give an exponential-time algorithm, as well as well-performing heuristics, and give excellent results for five sample viral genomes. Our resulting modified genomes have several times more unique restriction sites and reduce the maximum gap between adjacent sites by three to nine-fold.
Composite fermions and the fractional quantum Hall effect: essential role of the pseudopotential

Abstract The mean field (MF) composite fermion (CF) picture successfully predicts the band of low-lying angular momentum multiplets of fractional quantum Hall systems for any value of the magnetic field. This success cannot be attributed to a cancellation between Coulomb and Chern–Simons interactions between fluctuations beyond the mean field. It results instead from the short-range behavior of the Coulomb pseudopotential in the lowest Landau level (LL). The class of pseudopotentials for which the MFCF picture is successful can be defined, and used to explain the success or failure of the picture in different cases (e.g. excited LLs, charged magneto-excitons, and Laughlin quasiparticles in a CF hierarchy picture).
Computer tutors that know what they teach

Computer tutors hold the promise of providing truly individualized instruction. Lekan lists 910 Computer Assisted Instruction (CAI) programs, and this large number demonstrates the wide interest in the field of computer tutors.
Internal conversion tables part I: K-, L-, M-shell conversion coefficients for Z=30 to Z=103

Values of the internal conversion coefficient, number of electrons per photon emitted in a nuclear transition, are presented from a new relativistic self-consistent-field calculation which takes into account finite nuclear size, hole and exchange effects, experimental electron binding energies, and vacuum polarization. Coefficients are given for each value of Z ; for K, L , and M electron shells and L - and M -sub-shells; for nuclear-transition multipolarities E1…E4, M1…M4; and for various nuclear-transition energies up to 1500 keV. A program for finding values for other energies by spline interpolation is appended.
Synthesis of hindered biphenyls by sequential non-transition metal-catalyzed reaction/palladium-catalyzed cross-couplings.

The sequential reaction of 1,2-dihalobenzenes with aryllithiums followed by palladium-catalyzed cross-coupling reactions with Grignard reagents and arylboronic acids is described. This sequential reaction provides a convenient and expeditious access to tri-ortho substituted biaryl derivatives.
On the origin of fermion masses

Abstract We point out that if quarks and leptons are composite, their masses may arise mainly in a manner which does not violate electroweak symmetry. A toy model is given which illustrates this. Some implications are discussed, including one involving possible neutrino masses.
Picard Groups on Moduli of K3 Surfaces with Mukai Models

We discuss the Picard group of the moduli space K_g of quasi-polarized K3 surfaces of genus g≤12 and g≠11. In this range, K_g is unirational, and a general element in K_g is a complete intersection with respect to a vector bundle on a homogenous space, by the work of Mukai. In this paper, we find generators for the Picard group Pic_Q(K_g) using the Noether–Lefschetz (NL) theory. This verifies the NL conjecture on the moduli of K3 surfaces in these cases.
ENERGETICS OF STABLE AND METASTABLE LOW-TEMPERATURE IRON OXIDES AND OXYHYDROXIDES

Abstract The energetics of a set of synthetic iron oxides and oxyhydroxides were determined by transposed temperature drop calorimetry and high temperature solution calorimetry using sodium molybdate as a solvent at 979 K. The experiments allow the calculation of the enthalpy of formation from the elements of γ-Fe2O3 with tetragonal symmetry (812.7 ± 2.6 kJ/mol) and with cubic symmetry (−812.3 ± 2.5 kJ/mol) and β-FeOOH (557.6 ± 2.4 kJ/mol), values currently unavailable in the literature. Maghemite, γ-Fe2O3, is 15.3 ± 0.9 kJ/mol less stable in enthalpy than hematite, α-Fe2O3.
Multiresolution Match Kernels for gesture video classification

The emergence of depth imaging technologies like the Microsoft Kinect has renewed interest in computational methods for gesture classification based on videos. For several years now, researchers have used the Bag-of-Features (BoF) as a primary method for generation of feature vectors from video data for recognition of gestures. However, the BoF method is a coarse representation of the information in a video, which often leads to poor similarity measures between videos. Besides, when features extracted from different spatio-temporal locations in the video are pooled to create histogram vectors in the BoF method, there is an intrinsic loss of their original locations in space and time. In this paper, we propose a new Multiresolution Match Kernel (MMK) for video classification, which can be considered as a generalization of the BoF method. We apply this procedure to hand gesture classification based on RGB-D videos of the American Sign Language(ASL) hand gestures and our results show promise and usefulness of this new method.
Disclosure frequency and earnings management

Abstract We examine the relation between disclosure frequency and earnings management, and the impact of this relation on post-issue performance, for a sample of seasoned equity offerings (SEOs). We contend that firms with extensive disclosure are less likely to face information problems, leading to less earnings management and better post-issue performance. Our results confirm that disclosure frequency is inversely related to earnings management and positively associated with post-issue performance. We also find that transparency-reducing disclosure is concentrated in firms that substantially, but temporarily, increase disclosure prior to the offering. Such firms exhibit more earnings management and poorer post-SEO stock performance, on average.
Electrostatic theory of metal whiskers

It has been known for more than 60 years that fine metal whiskers can spontaneously form at the surface of a stressed metal, and that these whiskers produce random failures in computer servers, satellites, and electronic storage devices. A new study attributes the whiskers to minute electric field variations at metal surfaces, leading to the first predictive theory for whisker growth and length distribution.
The dry carbonate process: Carbon dioxide recovery from power plant flue gas

Abstract RTI’s Dry Carbonate Process, a solid sorbent CO 2 capture approach, has been developed as a retrofit technology for existing power plants. The process is based on the reversible reaction between sodium carbonate, CO 2 , and water vapor to form sodium bicarbonate. Concentrated CO 2 is recovered by a thermal-swing process. Field testing of a prototype Dry Carbonate Process has been completed with a total of 235 h of operation using natural gas- and coal-derived flue gases. The Dry Carbonate demonstrated >90% CO 2 capture and minimal adverse effects of exposure to SO 2 . Current R&D efforts are focussing on improving the process configuration and sorbent material to scale-up the process to a pilot unit capable of capturing 1 ton of CO 2 per day.
SUPRA-RPC: SUbprogram PaRAmeters in remote procedure calls

Remote-procedure calls (RPCs) allow distributed, high-level language programs to communicate and synchronize in the usual manner via subprogram calls. One of the great challenges in RPC research is to preserve the traditiional call semantics despite the distribution and heterogeneity of the new environment. The main contribution of SUPRA-RPC is in addressing the passing of subprograms as RPC parameters. In doing so, SUPRA overcomes a number of technical difficulties, stemming from scoping, side-effects and other sources. Since supporting subprogram RPC parameters is harder than supporting non-subprogram RPC parameters, the three (of six) components of the SUPRA architecture extend in novel ways the traditional functionality found in their counterparts in other RPC systems. The SUPRA stub generator extracts information not only from remote entry interfaces, but from any scope potentially referenced by a subprogram passed as an RPC parameter. In addition to the usual call- and accept-stubs and the marshaling and unmarshaling routines, the generator constructs out-of-scope access stubs, callback' and callback-handling-stubs, and modified parameter subprograms and others. The SUPRA run-time support manages a run-time symbol table to keep track of referencing environments and out-of-scope objects. When an out-of-scope object is unavailable for access or execution on the server, the object is reached by a synchronous, ‘under-the-covers’ callback. The SUPRA process management supports servers with independent threads of control, manages (possibly nested) callbacks and pools of callback handler threads, and maintains correct identification of thread-initiated calls or callbacks. A SUPRA prototype has been implemented on Sun Unix workstations. The prototype supports C, C++ and CommonLisp programs. A prototype graphical demonstration has been implemented as well, that represents RPC concepts in terms of common life objects and situations.
Aerodynamic investigation with focusing schlieren in a cryogenic wind tunnel

A flow visualization study was performed using a focusing schlieren system in the 0.3m Transonic Cryogenic Tunnel at NASA Langley Research Center. The system proved to be a useful flow visualization tool for flows as low as M = 0.4. This study marked the first verification of the focusing schlieren technique in a major subsonic/transonic wind tunnel and the first time that high-quality, detailed pictures of high-Reynolds-numbers flows were obtained in a cryogenic wind tunnel. This test was part of a development program to implement instrumentation techniques in cryogenic wind tunnels, with the ultimate aim to use them in the National Transonic Facility (NTF).
Polarization-Insensitive Ultralow-Power Second-Harmonic Generation Frequency-Resolved Optical Gating

We demonstrate polarization-insensitive ultralow-power second-harmonic generation (SHG) frequency-resolved optical gating (FROG) measurements with a fiber-pigtailed, aperiodically-poled lithium niobate (A-PPLN) waveguide by scrambling the polarization much faster than the measurement integration time.
Optimal Construction of Edge-Disjoint Paths in Random Regular Graphs

Given a graph G = (V, E) and a set of κ pairs of vertices in V, we are interested in finding, for each pair (ai, bi), a path connecting ai to bi such that the set of κ paths so found is edge-disjoint. (For arbitrary graphs the problem is NP-complete, although it is in P if κ is fixed.)We present a polynomial time randomized algorithm for finding edge-disjoint paths in the random regular graph Gn,r, for sufficiently large r. (The graph is chosen first, then an adversary chooses the pairs of end-points.) We show that almost every Gn,r is such that all sets of κ = Ω(n/log n) pairs of vertices can be joined. This is within a constant factor of the optimum.
Vertical temperature and density patterns in the Arctic mesosphere analyzed as gravity waves

Three series of rocket soundings were conducted from high latitude sites during winter. In the first series, four pitot pressure soundings were launched during a 13-hour period from Ft. Churchill, Canada (59° N) on January 31, and February 1, 1967. The second series consisted of one pitot sounding and two grenade soundings carried out during a 3-hour period on January 13–14, 1970. Temperature and wind profiles and one density profile were observed independently to obtain the thermodynamic structure, the wind structure, and thus their interdependence in the mesosphere. The third series of soundings was conducted from Point Barrow, Alaska (71° N) on December 6, 1971. This series consisted of five soundings of which the first two and the last two were pitot-grenade pairs. Temperature profiles from all soundings in each series were averaged, and a smooth curve (or series of smooth curves) drawn through the points. A hydrostatic atmosphere based on the average, measured temperature profile was computed, and deviations from the mean atmosphere were analyzed in terms of gravity wave theory. The vertical wavelengths of the deviations were 10–20 km, and the wave amplitudes slowly increased with height. The experimental data were matched by calculated gravity waves having a period ranging between 15 and 80 minutes and horizontal wavelengths of 60 to 280 km. Our interpretation is generally consistent with the results of others who have studied gravity-acoustic waves in the atmosphere. The wind measurements are consistent with the thermodynamic measurements. The results also suggest that gravity waves travelled from East to West with a horizontal phase velocity of approximately 60 m/s. DOI: 10.1111/j.2153-3490.1978.tb00849.x
Ring opening reactions of 2-methyleneoxetanes

Ring opening of 2-methyleneoxetanes with stabilized carbanion nucleophiles provides substituted ketones. The intermediate enolate can be trapped as its silylenol ether. If the 2-methyleneoxetane is exposed to more strongly basic carbanions, the corresponding homopropargylic alcohol is isolated in excellent yield. A variety of heteroatom nucleophiles also open the 2-methyleneoxetane in good to excellent yields.
Stellar Populations of Luminous Evolved Galaxies at z ~ 1.5

Observational evidence has been mounting over the past decade that at least some luminous (~2L*) galaxies have formed nearly all of their stars within a short period of time, only (1-2) × 109 yr after the big bang. These are examples of the first major episodes of star formation in the universe and provide insights into the formation of the earliest massive galaxies. We have examined in detail the stellar populations of six z ~ 1.5 galaxies that appear to be passively evolving, using both ground- and space-based photometry covering rest-frame UV to visible wavelengths. In addition, we have obtained medium-resolution spectroscopy for five of the six galaxies, covering the rest-frame UV portion of the spectrum. Spectral synthesis modeling for four of these galaxies favors a single burst of star formation more than 1 Gyr before the observed epoch. The other two exhibit slightly younger ages with a higher dust content and evidence for a small contribution from either recent star formation or active nuclei. The implied formation redshifts for the oldest of these sources are consistent with previous studies of passive galaxies at high redshift, and improved stellar modeling has shown these results to be quite robust. It now seems clear that any valid galaxy formation scenario must be able to account for these massive (~2 × 1011 M☉) galaxies at very early times in the universe.
Solid state quantum yield determination of a novel base photogenerator

Abstract The photoefficiency of a new class of base photogenerating materials, based on the photoremoval of the α,α-dimethyl-3,5-dimethoxybenzyloxycarbonyl (Ddz) group from masked amine-type bases, was investigated. The solid state quantum yield for the photogeneration of cyclohexylamine from its corresponding Ddz carbamate was evaluated at 280 nm using a number of quantitative IR methods. A value of 0.10 was found using the optimal method involving a comparison of the intensities of a strong IR reference band solely associated with the polymer matrix with the decreasing carbonyl absorption of the Ddz substrate. Comparable quantum yields were also found by using an intense band associated with the Ddz-masked amine, thus indicating the overall applicability and reliability of the method provided that careful choice of the reference band was made. The value of the quantum efficiency for the photodeprotection of Ddz-masked amines is sufficiently high for practical applications requiring the use of photogenerated base.
Electrochemical Intercalation of Lithium into Graphite

The results of a study of the electrochemical intercalation of lithium into Lonza KS15 artificial graphite in 1M PC/EC (50:50) electrolyte are presented here. Electrolyte decomposition reactions occur during the first discharge at about 0.8 V vs. Li metal and their extent is greatly reduced by addition of crown ethers with 12 crown 4 being most effective. A mechanism is proposed for electrolyte decomposition reactions which includes at least two types of process, namely, propylene and ethylene evolution and formation on the surface of graphite of a solid electrolyte interphase film which includes lithium alkyl carbonates. The stoichiometry of lithium intercalation into graphite is found to be inversely dependent on the cycling rates and electrode thickness and proportional to the amount of carbon black added to the graphite.
Data transmission equipment concepts for FIELDATA

FIELDATA is an integrated family of data processing and data transmission equipment being developed for Army use. A unique feature of this family is the almost complete disappearance of conventional distinctions between communications and data processing. This paper deals primarily with the concepts and techniques developed to create this evolutionary merger emphasizing the ways in which conventional communications concepts have been adapted to achieve a high degree of interoperability with computers and other data processing equipment, and an extraordinary degree of flexibility and adaptability of application.
Bad Dreams Under Alternative Anchors: Are the Consequences Different?

Using a simple model, this paper shows how a strict monetary rule exhibits characteristics similar to those of an exchange rate anchor, in terms of a lack of robustness in the presence of adverse expectations (bad dreams). More specifically, as an anticipated devaluation under an exchange rate rule leads to well-known contractionary effects, an anticipated increase in the money stock under a monetary rule, though initially expansionary, becomes contractionary when these expectations are not validated. This suggests that much of the criticism of an exchange rate anchor implicitly considers not another rule but rather, discretion as the alternative.
Acoustics of rotors utilizing circulation control

The acoustic characteristics of circulation-controlled rotors are examined by comparing data from three full-scale rotors: a conventional rotor, the X-Wing rotor, and the Circulations Control Rotor. Both the X-Wing rotor and Circulation Control Rotor had higher sound levels than the conventional rotor at identical advancing-tip Mach numbers. There is excess noise due to the compressor on the X-Wing rotor and excess broadband noise on the Circulation Control Rotor. The X-Wing rotor had lower sound levels than the conventional rotor at identical forward speeds because of the lower tip speed feasible with the use of circulation control.
The Long-Time Behavior of the Ricci Tensor under the Ricci Flow

We show that, given an immortal solution to the Ricci flow on a closed manifold with uniformly bounded curvature and diameter, the Ricci tensor goes to zero as . We also show that if there exists an immortal solution on a closed 3-dimensional manifold such that the product of the curvature and the square of the diameter is uniformly bounded, then this solution must be of type III.
Coded Cooperative Data Exchange in Multihop Networks

Consider a connected network of n nodes that all wish to recover k desired packets. Each node begins with a subset of the desired packets and exchanges coded packets with its neighbors. This paper provides necessary and sufficient conditions that characterize the set of all transmission strategies that permit every node to ultimately learn (recover) all k packets. When the network satisfies certain regularity conditions and packets are randomly distributed, this paper provides tight concentration results on the number of transmissions required to achieve universal recovery. For the case of a fully connected network, a polynomial-time algorithm for computing an optimal transmission strategy is derived. An application to secrecy generation is discussed.
Reduced invariant sets

Let K be a compact Lie group and W a finite-dimensional real K-module. Let X be a K-stable real algebraic subset of W. Let \({\mathcal{I}(X)}\) denote the ideal of X in \({\mathbb{R}[W]}\) and let \({\mathcal{I}_{K}(X)}\) be the ideal generated by \({\mathcal{I}(X)^{K}}\) . We find necessary conditions and sufficient conditions for \({{\mathcal{I}(X) = \mathcal{I}_{K}(X)}}\) and for \({{\sqrt{\mathcal{I}_{K}(X)} = \mathcal{I}(X)}}\) . We consider analogous questions for actions of complex reductive groups.
Calibration and flight performance of the long-slit imaging dual order spectrograph

We present preliminary results for the calibration and flight performance of the Long-Slit Imaging Dual Order Spectrograph (LIDOS), a rocket-borne instrument with a large dynamic range in the 900 - 1650 a bandpass. The instrument observes UV-bright objects with a CCD channel and fainter nebulosity with an MCP detector. The image quality and the detector quantum efficiencies were determined using the calibration and test equipment at the Johns Hopkins University, and further monitored using an on-board electron-impact calibration lamp. We review results from each of the three flights of the instrument.
Factorization is not violated

Abstract We show that existing proofs of factorization imply the cancellation of certain multiladder contributions that Gotsman, Levin, and Maor had suggested would invalidate the basic factorization theorem in QCD. No modifications of the original argument are necessary, although the details of the example offer useful insight into the mechanisms of factorization.
Searching for low weight pseudo-codewords

Belief propagation (BP) and linear programming (LP) decodings of low density parity check (LDPC) codes are discussed. We summarize results of instanton/pseudo-codeword approach developed for analysis of the error-floor domain of the codes. Instantons are special, code and decoding specific, configurations of the channel noise contributing most to the Frame-Error-Rate (FER). Instantons are decoded into pseudo- codewords. Instanton/pseudo-codeword with the lowest weight describes the largest Signal-to-Noise-Ratio (SNR) asymptotic of FER, while the whole spectra of the low weight instantons is descriptive of the FER vs SNR profile in the extended error-floor domain. First, we describe a general optimization method that allows to find the instantons for any coding/decoding. Second, we introduce LP-specific pseudo-codeword search algorithm that allows efficient calculations of the pseudo-codeword spectra. Finally, we discuss results of combined BP/LP error-floor exploration experiments for two model codes.
Dependence of Interstellar Turbulent Pressure on Supernova Rate

Feedback from massive stars is one of the least understood aspects of galaxy formation. We perform a suite of vertically stratified local interstellar medium (ISM) models in which supernova (SN) rates and vertical gas column densities are systematically varied based on the Schmidt-Kennicutt law. Our simulations have a sufficiently high spatial resolution (1.95 pc) to follow the hydrodynamic interactions among multiple SNe that structure the interstellar medium. At a given SN rate, we find that the mean mass-weighted sound speed and velocity dispersion decrease as the inverse square root of gas density. The sum of thermal and turbulent pressures is nearly constant in the midplane, so the effective equation of state is isobaric. In contrast, across our four models having SN rates that range from 1 to 512 times the Galactic SN rate, the mass-weighted velocity dispersion remains in the range 4-6 km s–1. Hence, gas averaged over ~100 pc regions follows P ∝ ρα with α ≈ 1, indicating that the effective equation of state on this scale is close to isothermal. Simulated H I emission lines have widths of 10-18 km s–1, comparable to observed values. In our highest SN rate model, superbubble blow-outs occur, and the turbulent pressure on large scales is 4 times higher than the thermal pressure. We find a tight correlation between the thermal and turbulent pressures averaged over ~100 pc regions in the midplane of each model, as well as across the four ISM models. We construct a subgrid model for turbulent pressure based on analytic arguments and explicitly calibrate it against our stratified ISM simulations. The subgrid model provides a simple yet physically motivated way to include SN feedback in cosmological simulations.
The impact of the two-tier plan/market system in chinese industry☆

Abstract There has been a great expansion in the role of the market mechanism in the distribution of industrial goods in China since the late 1970s. A two-tier system, whereby part of total production of each good is allocated by various kinds of directive plans, part by markets, has emerged. It is argued that the two-tier system has resulted in the demise of the direct role of mandatory planning in the allocation of industrial goods, and that the inherent dynamic tendencies of the system are leading to a continual increase in the share of the market over time. J. Comp. Econ. , September 1987, 11 (3), pp. 295–308. The World Bank, Washington, D.C. 20433.
Ridge migration, asthenospheric flow and the origin of magmatic segmentation in the global mid‐ocean ridge system

[1] Global observations of mid-ocean ridge (MOR) bathymetry demonstrate an asymmetry in axial depth across ridge offsets that is correlated with the direction of ridge migration. Motivated by these observations, we have developed two-dimensional numerical models of asthenospheric flow and melting beneath a migrating MOR. The modification of the flow pattern produced by ridge migration leads to an asymmetry in melt production rates on either side of the ridge. By coupling a simple parametric model of three dimensional melt focusing to our simulations, we generate predictions of axial depth differences across offsets in the MOR. These predictions are quantitatively consistent with the observed asymmetry.
Higher Regularity of Hölder Continuous Solutions of Parabolic Equations with Singular Drift Velocities

Motivated by an equation arising in magnetohydrodynamics, we prove that Holder continuous weak solutions of a nonlinear parabolic equation with singular drift velocity are classical solutions. The result is proved using the space–time Besov spaces introduced by Chemin and Lerner (J Differ Equ 121(2):314–328, 1995), combined with energy estimates, without any minimality assumption on the Holder exponent of the weak solutions.
Degenerate dispersive equations arising in the study of magma dynamics

An outstanding problem in Earth science is understanding the method of transport of magma in the Earth's mantle. Two proposed methods for this transport are percolation through porous rock and flow up conduits. Under reasonable assumptions and simplifications, both means of transport can be described by a class of degenerate nonlinear dispersive partial differential equations of the form: where (z, 0) > 0 and (z, t) → 1 as z → ±∞.Although we treat arbitrary n and m, the exponents are physically expected to be between 2 and 5 and 0 and 1, respectively.In the case of percolation, the magma moves via the buoyant ascent of a less dense phase, treated as a fluid, through a denser, porous phase, treated as a matrix. In contrast to classical porous media problems where the matrix is fixed and the fluid is compressible, here the matrix is deformable, with a viscous constitutive relation, and the fluid is incompressible. Moreover, the matrix is modelled as a second, immiscible, compressible fluid to mimic the process of dilation of the pores. Flow via a conduit is modelled as a viscously deformable pipe of magma, fed from below.Analogue and numerical experiments suggest that these equations behave akin to KdV and BBM; initial conditions evolve into a collection of solitary waves and dispersive radiation. As → 0, the equations become degenerate. A general local well-posedness existence theory is given for a physical class of data (roughly H1) via fixed point methods. The strategy requires positive lower bounds on (z, t). The key to global existence is the persistence of these bounds for all time. Furthermore, we construct a Lyapunov energy functional, which is locally convex about the uniform porosity state, ≡ 1, and prove (global in time) nonlinear dynamic stability of the uniform state for any m and n. For data which are large perturbations of the uniform state, we prove global in time well-posedness for restricted ranges of m and n. This includes, for example, the case n = 4,m = 0, where an appropriate uniform in time lower global on can be proved using the conservation laws. We compare the dynamics with that of other problems and discuss open questions concerning a larger range of exponents, for which we conjecture global existence.
Circadian fluctuations in ventricular response to atrial fibrillation

Abstract The ability of living organisms to synchronize their physiologic functions with the environment has been recognized since the first observations by de Mairan. 1 Renewed interest in circadian aspects of cardiovascular function was sparked by the observation of Muller et al 2 that acute myocardial infarction has a higher incidence during the morning hours. Subsequent studies have confirmed and extended this finding. For example, the incidence of sudden cardiac death, 3 the prevalence of ventricular arrhythmia 4 and myocardial ischemia, 5 as well as platelet aggregability increase in the morning and decline at night. Whereas diurnal variations in sinus rate can be readily examined, direct long-term monitoring of the function of the atrioventricular (AV) node is not feasible with current technology. However, in atrial fibrillation the ventricular response (VR) is determined in part by the refractoriness of the AV node. The purpose of this study was to examine diurnal variations in AV nodal refractoriness in patients with chronic atrial fibrillation.
Representing a Functional Curve by Curves with Fewer Peaks

In this paper, we study the problems of (approximately) representing a functional curve in 2-D by a set of curves with fewer peaks. Representing a function (or its curve) by certain classes of structurally simpler functions (or their curves) is a basic mathematical problem. Problems of this kind also find applications in applied areas such as intensity-modulated radiation therapy (IMRT). Let $\bf f$ be an input piecewise linear functional curve of size n. We consider several variations of the problems. (1) Uphill–downhill pair representation (UDPR): Find two nonnegative piecewise linear curves, one nondecreasing (uphill) and one nonincreasing (downhill), such that their sum exactly or approximately represents $\bf f$. (2) Unimodal representation (UR): Find a set of unimodal (single-peak) curves such that their sum exactly or approximately represents $\bf f$. (3) Fewer-peak representation (FPR): Find a piecewise linear curve with at most k peaks that exactly or approximately represents $\bf f$. Furthermore, for each problem, we consider two versions. For the UDPR problem, we study its feasibility version: Given e>0, determine whether there is a feasible UDPR solution for $\bf f$ with an approximation error e; its min-e version: Compute the minimum approximation error e ∗ such that there is a feasible UDPR solution for $\bf f$ with error e ∗. For the UR problem, we study its min-k version: Given e>0, find a feasible solution with the minimum number k ∗ of unimodal curves for $\bf f$ with an error e; its min-e version: given k>0, compute the minimum error e ∗ such that there is a feasible solution with at most k unimodal curves for $\bf f$ with error e ∗. For the FPR problem, we study its min-k version: Given e>0, find one feasible curve with the minimum number k ∗ of peaks for $\bf f$ with an error e; its min-e version: given k≥0, compute the minimum error e ∗ such that there is a feasible curve with at most k peaks for $\bf f$ with error e ∗. Little work has been done previously on solving these functional curve representation problems. We solve all the problems (except the UR min-e version) in optimal O(n) time, and the UR min-e version in O(n+mlog m) time, where m<n is the number of peaks of $\bf f$. Our algorithms are based on new geometric observations and interesting techniques.
Enhanced Electrical and Thermal Interconnects by the Self-Assembly of Nanoparticle Necks Utilizing Capillary Bridging

This work presents enhanced composite joints that support both electrical or thermal transport in electronic packages. The joints are sequentially formed by applying a nanoparticle suspension, evaporating a solvent, self-assembling of nanoparticles by capillary bridging, and the formation of so called “necks” between micron-sized features. This sequence is used to either form low temperature electrical joints under copper pillars or enhanced percolating thermal underfills with areal contacts between filler particles of the composite. The report discusses processing aspects of the capillary bridges evolution and of uniform neck formation, it discusses strategies to achieve mechanically stable necks, and it compares the performance of the achieved joints against state-of-the-art solutions.The capillary bridge evolution during liquid evaporation was investigated in copper pillar arrays and random particle beds. The vapor-liquid interface first penetrates locations of low pillar or particle density resulting in a dendritic fluid network. Once the network breaks up individual necks form. For aqueous nano-suspensions highly uniform necks with high yield were obtained by evaporation at 60°C. Isothermal conditions were preferred to yield equal neck counts at the cavity’s top and bottom surfaces. Mechanically stable silver necks required an annealing at only 150°C, dielectric necks an annealing at 140°C with a bi-modal approach. Therein polystyrene nanoparticles occupy interstitial positions in densly packed alumina necks, then melt and adhere to the alumina. The electrical necks showed a shear strength of 16 MPa, equivalent to silver joints used in power electronic packages. The thermal necks yielded a thermal conductivity of up to 3.8 W/mK, 5-fold higher than commercially available capillary thermal underfills.Copyright © 2013 by ASME
The X-ray evolution of galaxies: implications for future X-ray observatories

The X-ray evolution of the luminosity of normal galaxies is primarily driven by the evolution of their X-ray binary populations. The imprints left by a cosmological evolution of the star formation rate (SFR) will cause the average X-ray luminosity of galaxies to appear higher in the redshift range 1–3. As reported by White and Ghosh [ApJ, 504 (1998) L31] the profile of X-ray luminosity with redshift can both serve as a diagnostic probe of the SFR profile and constrain evolutionary models for X-ray binaries. In order to observe the high redshift (z>3) universe in the X-ray band, it is necessary to avoid confusion from foreground field galaxies. We report on the predictions of these models of the X-ray flux expected from galaxies and the implications for the telescope parameters of future deep universe X-ray observatories.
Effective Propagation Constants and Attenuation Rates in Media of Densely Distributed Coated Dielectric Particles with Size Distributions

The effective propagation constants and attenuation rates in dense nontenuous media with coated dielectric particles governed by size distributions are studied. A coated particle consists of two layers with different materials. In a dense medium, particles do not scatter independently and the effects of correlated scattering have to be included. The correlated scattering can be taken into account by using the quasicrystalline approximation (QCA) or the quasicrystalline approximation with coherent potential (QCA-CP). The Lippmann-Schwinger equation for coated particles is solved analytically to calculate the T-matrix for both QCA and QCA-CP. We also consider the dense medium with particle sizes governed by size distribution. The pair distribution functions for particles of different sizes are computed by using the Percus-Yevick approximation. For small particles, closed form analytic expressions are obtained for the complex effective propagation constants. For moderate size particles, the complex effective...