cssi/SciSciGPT-SciSciNet huggingface dataset:
Water-soluble octahedral polyammonium nanocapsules: synthesis and encapsulation studies

Abstract The syntheses of two water-soluble octahedral polyammonium nanocapsules 5e and 5f are described. Nanocapsule 5e was prepared via the TFA-catalyzed condensation reaction of six MOM-protected 4-hydroxybutyl-footed tetraformyl cavitands 3c with 12 ethylene diamines, followed by reduction and acidic hydrolysis of the intermediate octahedral polyimino nanocapsule. Nanocapsule 5f was prepared from 5e via the oxidation of the 4-hydroxybutyl feet to 3-carboxypropyl feet. Both nanocapsules are soluble in water below pH 5. 5f is also water-soluble above pH 7. In acidic aqueous solution, nanocapsule 5e encapsulates small negatively charged, partially hydrophobic guests, such as p -toluenesulfonic acid, N -BOC-aspartic acid, or 4-methylumbelliferyl phosphate. The single site microscopic binding constants for the latter guests are 150±30, 510±50, 1550±150 M −1 , respectively and were determined from 1 H NMR titrations and DOSY experiments by assuming a 6:1 binding model with six identical, independent binding sites per nanocapsule (statistical binding). 5e doesn't bind small neutral hydrophobic molecules in aqueous solution. However, both nanocapsules bind to nucleotides, such as ATP, dAMP, dGMP or TTP. NMR experiments support that nucleotides are not encapsulated, but bind to the outside of the nanocapsules.
Some Refinements of the Theory of the Viscous Screw Pump

Recently performed analysis for herringbone thrust bearings has been incorporated into the theory of the viscous screw pump for Newtonian fluids. In addition, certain earlier corrections for sidewall and channel curvature effects have been simplified. The result is a single, refined formula for the prediction of the pressure-flow relation for these pumps.
Representing Boolean functions as polynomials modulo composite numbers

Define the MOD m -degree of a boolean functionF to be the smallest degree of any polynomialP, over the ring of integers modulom, such that for all 0–1 assignments $$\vec x$$ , $$F(\vec x) = 0$$ iff $$P(\vec x) = 0$$ . We obtain the unexpected result that the MOD m -degree of the OR ofN variables is $$O(\sqrt[\tau ]{N})$$ , wherer is the number of distinct prime factors ofm. This is optimal in the case of representation by symmetric polynomials. The MOD n function is 0 if the number of input ones is a multiple ofn and is one otherwise. We show that the MOD m -degree of both the MOD n and $$\neg MOD_n$$ functions isN Ω(1) exactly when there is a prime dividingn but notm. The MOD m -degree of the MOD m function is 1; we show that the MOD m -degree of $$\neg MOD_m$$ isN Ω(1) ifm is not a power of a prime,O(1) otherwise. A corollary is that there exists an oracle relative to which the MOD m P classes (such as ⊕P) have this structure: MOD m P is closed under complementation and union iffm is a prime power, and MOD n P is a subset of MOD m P iff all primes dividingn also dividem.
Business Organization and the Myth of the Market Economy

Acknowledgments Introduction: the wealth of three nations Part I. Economic Institutions and Economic Performance: 1. Business organization and competitive advantage 2. Institutional foundations of industrial dominance and decline 3. Organizations and markets in capitalist development Part II. Intellectual Foundations and Intellectual Constraints: 4. The theory and history of capitalist development 5. The making of the market mentality Part III. 'The Marvels of the Market' Versus 'The Visible Hand': 6. The innovative business organization and transaction cost theory 7. Lending the economic institutions of capitalism a visible hand Part IV. Overcoming Intellectual Constraints: 8. Business organization and economic theory 9. Rigor and relevance in economics.
Infrared-radiofrequency double resonance spectroscopy of CH3F using a color center laser

Abstract A tunable color center laser has been used as the infrared radiation source for infrared-radio-frequency double resonance spectroscopy. The A1–A2 splitting (J, K = 1, l = 1 and J, K = 2, l = −1) in the ν4 vibrational state of CH3F has been studied. This technique has also been used to measure the electric dipole moment for the ν4 state, which has been determined to be 1.8332(23) D.
The Carathéodory topology for multiply connected domains I

We consider the convergence of pointed multiply connected domains in the Caratheodory topology. Behaviour in the limit is largely determined by the properties of the simple closed hyperbolic geodesics which separate components of the complement. Of particular importance are those whose hyperbolic length is as short as possible which we call meridians of the domain. We prove continuity results on convergence of such geodesics for sequences of pointed hyperbolic domains which converge in the Caratheodory topology to another pointed hyperbolic domain. Using these we describe an equivalent condition to Caratheodory convergence which is formulated in terms of Riemann mappings to standard slit domains.
Single‐Nucleotide Polymorphisms Interact to Affect ADH7 Transcription

Background The class IV alcohol dehydrogenase (ADH7, µ-ADH, σ-ADH) is important in the metabolism of ethanol and retinol. ADH7 is the only ADH not expressed in liver, instead being expressed mainly in the upper gastro-intestinal tract. Genome wide studies have identified significant associations between single nucleotide polymorphisms (SNPs) in ADH7 and alcoholism and cancer, but the causative variants have not been identified.
A Simple and Efficient Procedure for Oxidation of Sulfides to Sulfoxides on Hydrated Silica Gel with Ceric Ammonium Nitrate (Can) In Methylene Chloride

Abstract A simple, fast and efficient procedure for oxidation of sulfides to the corresponding sulfoxides with CAN mediated by hydrated silica gel in methylene chloride has been developed. To our knowledge, this is the first example of oxidation of sulfides with CAN in a non-aqueous media.
Damage modes and mechanisms of Si-Ge films under prompt soft X-ray radiation

Abstract Thermal and residual stresses in films exposed to sudden temperature changes are analyzed based on an elastoplastic-brittle idealization of film response. The results thus obtained are used to explain qualitatively the damage mechanisms of various failure modes observed in SiGe film deposited onto single-crystal silicon substrates exposed to soft X-ray radiation for a short duration of time.
Witten deformation and the equivariant index

Let M be a compact Riemannian manifold endowed with an isometric action of a compact, connected Lie group. The method of the Witten deformation is used to compute the virtual representation-valued equivariant index of a transversally elliptic, first order differential operator on M. The multiplicities of irreducible representations in the index are expressed in terms of local quantities associated to the isolated singular points of an equivariant bundle map that is locally Clifford multiplication by a Killing vector field near these points.
Path Hitting in Acyclic Graphs

An instance of the path hitting problem consists of two families of paths, ${\mathcal{D}}$and ℋ, in a common undirected graph, where each path in ℋ is associated with a non-negative cost. We refer to ${\mathcal{D}}$and ℋ as the sets of demand and hitting paths, respectively. When p∈ℋ and $q\in{\mathcal{D}}$share at least one mutual edge, we say that p hits q. The objective is to find a minimum cost subset of ℋ whose members collectively hit those of ${\mathcal{D}}$. In this paper we provide constant factor approximation algorithms for path hitting, confined to instances in which the underlying graph is a tree, a spider, or a star. Although such restricted settings may appear to be very simple, we demonstrate that they still capture some of the most basic covering problems in graphs. Our approach combines several novel ideas: We extend the algorithm of Garg, Vazirani and Yannakakis (Algorithmica, 18:3–20, 1997) for approximate multicuts and multicommodity flows in trees to prove new integrality properties; we present a reduction that involves multiple calls to this extended algorithm; and we introduce a polynomial-time solvable variant of the edge cover problem, which may be of independent interest.
Nosocomial bacteremia-induced increases in abscess formation correlate with in vitro upregulation of macrophage procoagulant activity

Objective : To evaluate the hypothesis that sublethal exposure to common nosocomial pathogens can alter the host response to a later, distant infectious insult (peritonitis and intraperitoneal abscess formation), and that these changes are related to the induction of macrophage procoagulant activity. Design : A multiexperiment, randomized, controlled trial. Setting : Animal research laboratory of a university medical center. Subjects : One hundred sixty-five Balb/c mice, weighing 20 to 25 g, were used for in vivo experiments and as the source of peritoneal macrophages for in vitro experiments. Interventions : Nine groups of mice (n = 10 to 18 per group) were twice systemically pre-exposed to sublethal amounts of live Escherichia coli, Enterobacter cloacae, Pseudomonas aeruginosa, Staphylococcus epidermidis, Enterococcus faecalis, or Candida albicans, or to 2.5 or 5.0 μg E. coli lipopolysaccharide O26 :B6. One week later, mice underwent the induction of mixed E. coli/Bacteroides fragilis peritonitis, leading to abscess formation. In parallel experiments in vitro, 10 6 mouse peritoneal macrophages were incubated with similar amounts of nosocomial pathogens or lipopolysaccharide to determine the induction of macrophage procoagulant activity. Measurements and Main Results : The three Gram-negative bacilli tested significantly upregulated both abscess formation and macrophage procoagulant activity, with a strong linear correlation between abscess formation and procoagulant activity. These effects were not seen with the Gram-positive cocci or with C. albicans. Pre-exposure of mice to endotoxin alone did not alter later abscess formation, but did increase macrophage procoagulant activity. Conclusions : Sublethal exposure to some Gram-negative nosocomial pathogens can significantly alter a host's response to a later, distant, infection, even when caused by different bacteria. In the case of peritonitis and intraperitoneal abscess formation, these changes may be mediated by the upregulation of macrophage procoagulant activity. The presence of endotoxin alone does not completely explain these phenomena. (Crit Care Med 1995 ; 23 :1554-1559)
The impact of a trade on national best bid and offer quotes: a new approach to modeling irregularly spaced data☆

Abstract In 1975, amendments to the Security Exchange Act of 1934 mandated the development of a national market system. In response to this mandate, securities listed on the New York Stock Exchange may trade simultaneously on multiple markets. This paper investigates the differential impact of trades executed in the NYSE and regional markets on the national best bid and offer quotes by using a trade and quote revision vector autoregression system. The analysis also introduces a new approach for modeling data collected on irregularly spaced intervals that explicitly estimates a rate at which lagged information is being discounted by incorporating time into the model specification. The results indicate that trades on the regional markets have a smaller, but still significant impact on the price process and that the spacing between observations contains valuable information in modeling the price process.
Design and Optimization of High Performance Adsorption-Based Thermal Battery

Electric vehicle (EV) technology faces a substantial challenge in terms of driving range, especially when the vehicle’s climate control system relies entirely on the onboard electric battery. Therefore, we are developing an advanced adsorption-based thermal battery (ATB) capable of delivering both heating and cooling for electric vehicles with minimal use of the electric battery bank. While adsorption based climate control systems offer the advantage of direct usage of primary thermal energy sources for operation, they typically have low COP values, and are often bulky and heavy. A compact and lightweight ATB is necessary to replace existing climate control systems in EVs that use electric battery for operation. In this paper, we present a detailed computational analysis of adsorption kinetics taking place within an adsorption bed that is capable of delivering large cooling and heating capacities by making use of novel adsorbents. The overall design of the adsorption bed, which is a critical element in achieving a high performance thermal battery, is also discussed. To make performance predictions, we characterized the adsorbents to obtain their thermophysical and transport properties as well as adsorption characteristics. The model consequently incorporates these measured properties to predict the performance variation as a function of time. This work provides the critical parameters affecting heating and cooling rates, and identifies avenues for further improvement in the overall performance of the thermal battery.Copyright © 2013 by ASME
A Deep X‐Ray Observation of NGC 4258 and Its Surrounding Field

We present a deep X-ray observation of the low-luminosity active galactic nucleus in NGC 4258 (M 106) using the Advanced Satellite for Cosmology and Astrophysics(ASCA). Confirming previous results, we find that the X-ray spectrum of this source possesses several components. The soft X-ray spectrum ( ) is dominated by thermal emission from optically-thin plasma with . The hard X-ray emission is clearly due to a power-law component with photon index absorbed by a column density of . The power-law is readily identified with primary X-ray emiss ion from the AGN central engine. Underlying both of these spectral components is an additional continuum which is possibly due to thermal emission of a very hot gaseous component in the anomalous arms and/or the integrated hard emission of X-ray binaries in the host galaxy. We also clearly detect a narrow iron K emission line at . No broad component is detected. We suggest that the bulk of this narrow line comes from the accretion dis k and, furthermore, that the power-law X-ray source which excites this line emission (which is typically identi fied with a disk corona) must be at least in extent. This is in stark contrast to many higher-luminosity Seyfertgalaxies which display a broad iron line indicating a small ( ) X-ray emitting region. It must be stressed that this study constrains the size of the X-ray emitting corona rather than the presence/absence of a radiatively efficient accretion disk in the innermost regions. If, instead, a substantial fraction of the observe d narrow line originates from material not associated with the accretion disk, limits can be placed on the parameter spa ce of possible allowed relativistically broad iron lines. We include a discussion of various aspects of iron line limb-darkening for highly inclined sources, including the effect of gravitational light-bending on the apparent limb -darkening law. By comparing our data with previous ASCA observations, we find marginal evidence for a change in absor bing column density through to the central engine, and good evidence for a change in the AGN flux. We concl ude with a brief discussion of two serendipitous sources in our field of view; the QSO Q1218+472 and a putative cluster of galaxies. Subject headings: accretion, accretion disks - black hole physics - galaxies: active - galaxies: individual: NGC 4258 - X-rays:galaxies
The Shapes of Dense Cores and Bok Globules

The shapes of isolated Bok globules and embedded dense cores of molecular clouds are analyzed using a nonparametric kernel method, assuming the alternate hypotheses that they are randomly oriented prolate objects or that they are randomly oriented oblate objects. In all cases, the prolate hypothesis gives a better fit to the data. If Bok globules are oblate spheroids, they must be very flattened; the average axis ratio is γ ≈ 0.3, and no globules can have γ 0.7. If Bok globules are prolate, their intrinsic flattening is not as great, with a mean axis ratio γ ≈ 0.5. For most data samples of dense cores embedded within molecular clouds, the randomly oriented oblate hypothesis can be rejected at the 99% one-sided confidence level. If the dense cores are prolate, their mean axis ratio is in the range γ = 0.4–0.5. Analysis of the data of Nozawa et al. reveals that dense cores are significantly different in shape from the clouds in which they are embedded. The shapes of dense cores are consistent with their being moderately flattened prolate spheroids; clouds have flatter apparent shapes and are statistically inconsistent with a population of axisymmetric objects viewed at random angles.
Promoting Condoms in Brazil to Men Who Have Sex with Men

DKT International is a non-profit social marketing enterprise whose mission is to provide safe, affordable options for family planning and STI/HIV prevention. In Brazil, DKT sells male and female condoms to mostly lower-income couples nationwide. This paper is about the introduction of a ribbed, lubricated, latex condom called Affair to the Brazilian market in 2000. Sales were initially very low, but based on reports that Affair was well liked by some men who have sex with men, we took the opportunity to give Affair that positioning. We worked with our advertising agency, a local research company and Dignidade, a Brazilian NGO working for the rights of men who have sex with men. Two new products--a baggy condom called Affair Sensation and a complimentary lubricating gel called Affair Personal Lubricant--with new packaging and a promotional campaign were launched in February 2006. The billboard advertisement generated controversy in Sao Paulo, where the Advertising Council required it to be taken down due to complaints. However, the controversy helped promotion and at the same time generated public debate on sexuality and human rights. Our overall experience has been positive, sales are up and we have received messages of support for the products and their promotion from consumers.
Competition among Financial Intermediaries When Diversification Matters

Abstract Many models predict that the diversification and efficiency of financial intermediaries (“banks”) increases with their size, so that a relatively unrestricted banking sector will settle into an equilibrium with several large, well-diversified, and competitive banks. However, this prediction is at odds with the actual pattern of unrestricted banking sector evolution in many countries. I develop a model that motivates this actual pattern and examine the model's implications for regulatory policy. I show that an investor's return from a bank depends on the number of investors using that bank; this adoption externality makes investor beliefs about other investors' actions critical for bank competition. In a young banking system with free entry, coordination problems lead to excessive fragmentation, and debt overhang makes it difficult for small banks to capture additional market share. As the system matures, many banks fail, and the survivors become the focus of investor beliefs; these incumbents gain a strong advantage over entrants, facilitating collusion. Entry restrictions reduce fragmentation but aid collusion, while government insurance for investors reduces incumbency advantage and collusion but may cause excessive fragmentation. Thus, regulators may wish to impose temporary entry restrictions, along with partial insurance. These results are consistent with historical evidence from several countries.Journal of Economic LiteratureClassification Numbers: G21, G22, L13.
Atomic routing games on maximum congestion

We study atomic routing games on networks in which players choose a path with the objective of minimizing the maximum congestion along the edges of their path. The social cost is the global maximum congestion over all edges in the network. We show that the price of stability is 1. The price of anarchy, PoA, is determined by topological properties of the network. In particular, PoA=O(?+logn), where ? is the length of the longest path in the player strategy sets, and n is the size of the network. Further, ??1?PoA?c(?2+log2n), where ? is the length of the longest cycle in the network, and c is a constant.
Sequential Traffic Flow Optimization with Tactical Flight Control Heuristics

‡A sequential optimization method is applied to manage air traffic flow under uncertainty in airspace capacity and demand. To support its testing, a decision support system is developed by integrating a deterministic integer programming model for assigning delays to aircraft under en route capacity constraints to reactively account for system uncertainties. To reduce computational complexity, the model assigns only departure controls, while a tactical control loop consisting of a shortest path routing algorithm and an airborne holding algorithm refines the strategic plan to keep flights from deviating into capacity constrained airspace. This integrated approach is used to conduct thirty-two, 6-hour fast-time simulation experiments to explore variations in the number and severity of departure controls, tactical reroutes, and airborne holding controls. Three feasible types of traffic flow controls emerged. The first type relied primarily on departure controls and strategic reroutes on the 300 to 400 nmi look-ahead horizon and worked best when rerouting occurred at a frequency of 10 to 15 minutes. The second type generated more tactical reroutes on the 200 ‐ 300 nmi look-ahead horizon and required little airborne holding or pre-departure control when rerouting occurred at a frequency of 5 minutes. The last type relied heavily on airborne holding controls and infrequent updates to the weather avoidance reroutes. This last type was the least desirable solution due to the impact of its airborne holding on airspace complexity and airspace users.
The singularities of the principal component of the Hilbert scheme of points

Abstract Haiman proved the remarkable result that the isospectral Hilbert scheme of points in the plane is normal, Cohen–Macaulay and Gorenstein. This implies the n! conjecture and the positivity conjecture for the Kostka–Macdonald coefficients. In addition, he conjectured that the isospectral Hilbert scheme over the principal component of Hilb n ( C d ) is Cohen–Macaulay for any d , n ⩾ 1 . We provide a counterexample to the conjecture.
Integrality in Stochastic Inventory Models

We study several finite-horizon, discrete-time, dynamic, stochastic inventory control models with integer demands: the newsvendor model, its multi-period extension, and a single-product, multi-echelon assembly model. Equivalent linear programs are formulated for the corresponding stochastic dynamic programs, and integrality results are derived based on the total unimodularity of the constraint matrices. Specifically, for all these models, starting with integer inventory levels, we show that there exist optimal policies that are integral. For the most general single-product, multi-echelon assembly system model, integrality results are also derived for a practical alternative to stochastic dynamic programming, namely, rolling-horizon optimization by a similar argument. We also present a different approach to prove integrality results for stochastic inventory models. This new approach is based on a generalization we propose for the one-dimensional notion of piecewise linearity with integer breakpoints to higher dimensions. The usefulness of this new approach is illustrated by establishing the integrality of both the dynamic programming and rolling-horizon optimization models of a two-product capacitated stochastic inventory control system.
Filtered ends of infinite covers and groups

Abstract Let f : A → B be a covering map. We say that A has e filtered ends with respect to f (or B ) if, for some filtration { K n } of B by compact subsets, A − f − 1 ( K n ) “eventually” has e components. The main theorem states that if Y is a (suitable) free H -space, if K H has infinite index, and if Y has a positive finite number of filtered ends with respect to H ∖ Y , then Y has one filtered end with respect to K ∖ Y . This implies that if G is a finitely generated group and K H G are subgroups each having infinite index in the next, then 0 e ( G , H ) ∞ implies that e ( G , K ) = 1 , where e ( ⋅ , ⋅ ) is the number of filtered ends of a pair of groups in the sense of Kropholler and Roller.
Enhancement of Tribological Performance via Innovative Tooling Design for Extrusion Processes

A novel design of extrusion tooling is proposed. This process segments the traditional die set into three separate pieces, a punch, a wall die, and a bottom die. Additionally, the wall die is given the freedom to move along the axis of the punch and a high pressure lubricant is supplied to the interface between the wall and bottom dies. Preliminary tests of the segmented tooling show that, if the tribological conditions are severe enough, the forming load will decrease in comparison to a conventional extrusion system.
Throughput Analysis of Buffer-Constrained Wireless Systems in the Finite Blocklength Regime

In this paper, wireless systems operating under queueing constraints in the form of limitations on the buffer violation probabilities are considered. The throughput of wireless systems operating under such constraints is captured by the effective capacity formulation. It is assumed that finite blocklength codes are employed for transmission. Under this assumption, a recent result on the channel coding rate in the finite blocklength regime is incorporated into the analysis and the throughput achieved with such codes in the presence of queueing constraints is identified. Interactions between the effective rate, queueing constraints, error probabilities, and blocklength values are investigated. In particular, it is shown that for given signal-to-noise ratio, blocklength, and quality of service exponent, the effective rate is maximized at a unique decoding error probability value.
A SHARP BOUND FOR THE AREA OF MINIMAL SURFACES IN THE UNIT BALL

Let Σ be a k-dimensional minimal surface in the unit ball B n which meets the boundary ∂ B n orthogonally. We show that the area of Σ is bounded from below by the volume of the unit ball in $${\mathbb{R}^k}$$ .
The real puzzle of blackmail: An informational approach

Abstract The “puzzle” of blackmail is that threats to reveal private information that would be harmful to someone in exchange for money are illegal, but revelation is not. The resolution is that concealment of information about product quality impedes the efficient operation of markets, whereas revelation promotes it. The real puzzle is why possessors are not naturally inclined to sell to uninformed parties, who value the information more than would-be blackmail victims. The answer has to do with the public good qualities of information, which create an appropriability problem in transactions with uninformed parties. The paper also discusses incentives to acquire compromising information.
Homological Dimensions and Regular Rings

Abstract A question of Avramov and Foxby concerning injective dimension of complexes is settled in the affirmative for the class of noetherian rings. A key step in the proof is to recast the problem on hand into one about the homotopy category of complexes of injective modules. Analogous results for flat dimension and projective dimension are also established.
Leader election using loneliness detection

We consider the problem of leader election (LE) in single-hop radio networks with synchronized time slots for transmitting and receiving messages. We assume that the actual number n of processes is unknown, while the size u of the ID space is known, but is possibly much larger. We consider two types of collision detection: strong (SCD), whereby all processes detect collisions, and weak (WCD), whereby only non-transmitting processes detect collisions. We introduce loneliness detection (LD) as a key subproblem for solving LE in WCD systems. LD informs all processes whether the system contains exactly one process or more than one. We show that LD captures the difference in power between SCD and WCD, by providing an implementation of SCD over WCD and LD. We present two algorithms that solve deterministic and probabilistic LD in WCD systems with time costs of $${\mathcal{O}(\log \frac{u}{n})}$$ and $${\mathcal{O}(\min( \log \frac{u}{n}, \frac{\log (1/\epsilon)}{n}))}$$ , respectively, where $${\epsilon}$$ is the error probability. We also provide matching lower bounds. Assuming LD is solved, we show that SCD systems can be emulated in WCD systems with factor-2 overhead in time. We present two algorithms that solve deterministic and probabilistic LE in SCD systems with time costs of $${\mathcal{O}(\log u)}$$ and $${\mathcal{O}(\min ( \log u, \log \log n + \log (\frac{1}{\epsilon})))}$$ , respectively, where $${\epsilon}$$ is the error probability. We provide matching lower bounds.
A Bayesian nonparametric meta‐analysis model

In a meta-analysis, it is important to specify a model that adequately describes the effect-size distribution of the underlying population of studies. The conventional normal fixed-effect and normal random-effects models assume a normal effect-size population distribution, conditionally on parameters and covariates. For estimating the mean overall effect size, such models may be adequate, but for prediction, they surely are not if the effect-size distribution exhibits non-normal behavior. To address this issue, we propose a Bayesian nonparametric meta-analysis model, which can describe a wider range of effect-size distributions, including unimodal symmetric distributions, as well as skewed and more multimodal distributions. We demonstrate our model through the analysis of real meta-analytic data arising from behavioral-genetic research. We compare the predictive performance of the Bayesian nonparametric model against various conventional and more modern normal fixed-effects and random-effects models.
On the Local Isometric Embedding in R^3 of Surfaces with Gaussian Curvature of Mixed Sign

We study the old problem of isometrically embedding a 2-dimensional Riemannian manifold into Euclidean 3-space. It is shown that if the Gaussian curvature vanishes to finite order and its zero set consists of two Lipschitz curves intersecting transversely at a point, then local sufficiently smooth isometric embeddings exist.
Domain walls and superpotentials from M-theory on Calabi–Yau three-folds

Compactification of M-theory in the presence of G-fluxes yields N = 2 five-dimensional gauged supergravity with a potential that lifts all supersymmetric vacua. We derive the effective superpotential directly from the Kaluza–Klein reduction of the eleven-dimensional action on a Calabi–Yau three-fold and compare it with the superpotential obtained by means of calibrations. We discuss an explicit domain wall solution, which represents five-branes wrapped over holomorphic cycles. This solution has a “running volume” and we comment on the possibility that quantum corrections provide a lower bound allowing for an AdS5 vacuum of the 5-dimensional supergravity.
Performance and stability of hypervelocity aircraft flying on a minor circle

Abstract The equations of motion pertinent to the study of steady and perturbed motions of a rigid vehicle flying on a minor circle at constant altitude above a spherical non-rotating earth are presented. Solutions to the steady-state equations (performance) and perturbation equations (stability) are presented in the form of altitude-speed regions where flight is possible, and root loci, respectively. The linearized equations and performance boundaries are discussed. The principal conclusions are that steady flight is limited mainly by available thrust, and that characteristic oscillations about the steady-flight condition are poorly damped. Minor instabilities were found in all cases examined. New characteristic modes, not present in conventional flight, are discussed—they involve the movement of the vehicle mass-centre relative to the equilibrium flight trajectory. A representative vehicle was chosen for which numerical values were obtained.
Shock Wave Propagation and Spallation Study in Laser Shock Peening

This paper deals with the spallation induced by shock wave propagation in targets during the laser shock peening process. Physical aspects concerning laser-matter interaction, shock wave propagation, and spallation are considered. A continuous kinetic model for the spallation process is included in a one-dimensional finite-difference hydrodynamic code using Lagrangian coordinates in order to calculate the laser-induced spallation phenomena. Shock wave propagation in solids is calculated and validated by experimental data. The spallation zone location is then calculated for various materials with different thickness of foils and various laser shock peening parameters. The numerical simulations are compared with previously reported experimental results and good agreement is obtained for the spallation threshold and damage zone location.
Physical activity and prostate gene expression in men with low risk prostate cancer

Vigorous physical activity after diagnosis of localized prostate cancer may reduce the risk of disease progression and prostate cancer-specific mortality. The molecular mechanisms by which physical activity may exert protective effects in the prostate remain unknown. We examined the associations between self-reported physical activity and gene expression patterns in morphologically normal prostate tissue of 71 men with low-risk prostate cancer on active surveillance. Differential gene expression, gene set, and pathway analyses were conducted comparing dichotomous groups defined by type, intensity, and amount of physical activity reported. Cell cycling and DNA repair pathways were up-regulated in men who participated in ≥ 3 h/week vigorous activity compared with men who did not. In addition, canonical pathways involved in cell signaling and metabolism, the cellular effects of sildenafil (Viagra), and the Nrf2-mediated oxidative stress response were modulated in men who reported ≥ 3 h/week of vigorous activity. Differential expression analysis at the individual gene level revealed modest differences between men who performed vigorous activity for ≥ 3 h/week and those who did not. There were no differences in prostate gene expression in comparisons with exercise groupings that did not consider both duration and intensity of activity. Prostate gene expression and pathway analyses revealed sets of transcripts that may be modulated in normal prostate tissue by participating in ≥ 3 h/week of vigorous activity after diagnosis of low-risk prostate cancer. These findings suggest potential biological mechanisms by which vigorous activity may reduce risk of prostate cancer progression and warrant further study and validation.
Drosophila Embryogenesis Scales Uniformly across Temperature in Developmentally Diverse Species

Temperature affects both the timing and outcome of animal development, but the detailed effects of temperature on the progress of early development have been poorly characterized. To determine the impact of temperature on the order and timing of events during Drosophila melanogaster embryogenesis, we used time-lapse imaging to track the progress of embryos from shortly after egg laying through hatching at seven precisely maintained temperatures between 17.5°C and 32.5°C. We employed a combination of automated and manual annotation to determine when 36 milestones occurred in each embryo. D. melanogaster embryogenesis takes 33 hours at 17.5°C, and accelerates with increasing temperature to a low of 16 hours at 27.5°C, above which embryogenesis slows slightly. Remarkably, while the total time of embryogenesis varies over two fold, the relative timing of events from cellularization through hatching is constant across temperatures. To further explore the relationship between temperature and embryogenesis, we expanded our analysis to cover ten additional Drosophila species of varying climatic origins. Six of these species, like D. melanogaster, are of tropical origin, and embryogenesis time at different temperatures was similar for them all. D. mojavensis, a sub-tropical fly, develops slower than the tropical species at lower temperatures, while D. virilis, a temperate fly, exhibits slower development at all temperatures. The alpine sister species D. persimilis and D. pseudoobscura develop as rapidly as tropical flies at cooler temperatures, but exhibit diminished acceleration above 22.5°C and have drastically slowed development by 30°C. Despite ranging from 13 hours for D. erecta at 30°C to 46 hours for D. virilis at 17.5°C, the relative timing of events from cellularization through hatching is constant across all species and temperatures examined here, suggesting the existence of a previously unrecognized timer controlling the progress of embryogenesis that has been tuned by natural selection as each species diverges.
Preparation of Tethered Aldehyde Ynoates and Ynones by Ring Fragmentation of Cyclic γ-Oxy-β-hydroxy-α-diazo Carbonyls

Cyclic γ-oxy-β-hydroxy-α-diazo carbonyls undergo Lewis acid induced ring fragmentation to provide either ynoates or ynones tethered to an aldehyde, ketone, or ester. The fragmentation precursors are convenient to prepare by adding lithiated α-diazo carbonyls to α-oxy ketones. The fragmentation appears general and provides a variety of functional group-rich products in good to excellent yield.
Measurement of acoustic shielding by a turbulent jet

The acoustic shielding properties of a turbulent jet have been investigated experimentally. The experimental arrangement consisted of an acoustic point source and a turbulent shielding jet. The source and jet parameters investigated include the source frequency, source spectrum, jet velocity, jet heating by simulation and the lateral and longitudinal source positions with respect to the shielding jet. It is found that the maximum sound attenuation provided by the shielding jet depends on the balance between refraction and diffraction. Over the frequency range investigated, the redistribution of sound by the shielding air jet is power conserving. Comparison between measurement and prediction based on an idealized cylindrical uniform jet model indicates that the spreading and decay of the flow field in real jets are important. Comparisons between the present data trends and those reported for jet-by-jet shielding suggest that the major effects observed in the latter are acoustical rather than aerodynamical.
Decomposition of the height function of Scherk's first surface☆

We show that Scherk's first surface, a one-parameter family of solutions to the minimal surface equation, may be written as a linear superposition of other solutions with specific parametric values.
Indirect detection of neutralino dark matter up to TeV scale

Abstract In this paper, we will describe the results of SUSY parameter space searches including minimal supergravity, non-universal supergravity and minimal supersymmetry and the implications on the indirect detection of neutralino dark matter. We give special attention to the effects of detector thresholds, solar absorption of neutrinos and hadronization of neutralino annihilation products. These effects are known to be important in calculating accurate event rates [1]. We chose also to focus on models which predict a heavy lightest neutralino (several hundred GeV to several TeV). These models have been selected for several reasons including their inaccessibility in future collider searches.
International Business in American MBA Programs—Can We Silence the Critics?

Abstract Many criticisms are being leveled against both the teaching and teachers (content and delivery) of international business courses in American MBA programs. Using empirical evidence from 117 professors of international business from all regions of the United States except Hawaii and Alaska, this study found that 75% of them had conducted research and consulted for international companies, and 71% had doctorates in international business (36%), general management (32%), or international economics (3%). Numbers of published articles, on average, compared favorably with those of accounting faculty from another study. Using these and other criteria, we found that overall the international business faculty were qualified to teach global issues.
Beyond Reppe: Building Substituted Arenes by [2+2+2] Cycloadditions of Alkynes

Synthetic sequel: The transition-metal-catalyzed [2+2+2] cycloaddition is an established method for the construction of carbocyclic frameworks but is often plagued by poor selectivity. Recent literature paints a promising picture—a more general metal-catalyzed [2+2+2] cycloaddition can be accomplished intermolecularly using three separate alkynes to furnish highly substituted arenas (see scheme).
Coordinating with SOHO

Abstract I describe how to maximise the chances of achieving a successful coordinated observation campaign together with SOHO instruments (and TRACE). The ground rules, common pitfalls, useful resources and some essential “tricks of the trade” are covered. The most important hints are: start early, make contact with the instrument teams and the SOCs ( soc@soc.nascom.nasa.gov ), ask whenever in doubt, check the calendar, and be specific.
The Ultraviolet-Far-Infrared Energy Budget of the Gravitationally Lensed Lyman Break Galaxy MS 1512-CB58

A 2 hr service-mode SCUBA observation of the gravitationally lensed Lyman break galaxy MS 1512-cB58 (hereafter cB58) resulted in a 3 σ upper limit of 3.9 mJy at 850 μm. A comparison of this upper limit with values expected from rest-UV–optical measurements of extinction suggests that the dust temperature (Td) and/or emissivity index (β) in cB58 may be substantially higher than is seen in local galaxies, or that the attenuation curve in cB58 may be even gentler than the already quite mild SMC dust law. If dust temperature Td and emissivity index β in cB58 are similar to those seen in local IRAS-selected galaxies, then cB58's dust mass is Md 107.7 M⊙, and its star formation rate is SFR 10 M⊙ yr-1 (for q0 = 0.1, H0 = 75 km s-1 Mpc-1). This SFR upper limit is lower than the star formation rate measured from Hα, thus giving further support to the notion that (Td, β) values in cB58 are higher than those seen in local galaxies. It thus appears that our understanding of dust in this extensively studied Lyman break galaxy is poor, and observations at other wavelengths are needed to better understand dust at high redshift. Such observations can be provided by the upcoming SIRTF mission for which cB58's expected flux densities are calculated.
Dynamical systems method (DSM) for nonlinear equations in Banach spaces

Abstract The DSM (dynamical systems method) is justified for nonlinear operator equations in a Banach space. The main assumption is on the spectral properties of the Frechet derivative of the operator at a suitable point. A singular perturbation problem related to the original equation is studied.
On the connectedness of the moduli space of Calabi-Yau manifolds

We show that the moduli space of all Calabi-Yau manifolds that can be realized as hypersurfaces described by a transverse polynomial in a four-dimensional weighted projective space, is connected. This is achieved by exploiting techniques of toric geometry and the construction of Batyrev that relate Calabi-Yau manifolds to reflexive polyhedra. Taken together with the previously known fact that the moduli space of all CICY's is connected, and is moreover connected to the moduli space of the present class of Calabi-Yau manifolds (since the quintic threefold P4[5] is both CICY and a hypersurface in a weighted P4) this strongly suggests that the moduli space of all simply connected Calabi-Yau manifolds is connected. It is of interest that singular Calabi-Yau manifolds corresponding to the points in which the moduli spaces meet are often, for the present class, more singular than the conifolds that connect the moduli spaces of CICY's.
Linking the Power Sources of Emission‐Line Galaxy Nuclei from the Highest to the Lowest Redshifts

This dissertation searches for common grounds for the diversity of properties exhibited by the emission-line nuclei of galaxies, from large look-back times to the local universe. I present results of (1) a program of high signal-to-noise spectroscopy for 44 quasars using the MMT and Keck obz 4 servatories; (2) a detailed analysis of the ultraviolet and optical spectral behavior of 22 narrow-line Seyfert 1 (NLS1) galaxies based on archival Hubble Space Telescope (HST) spectra; (3) an in-depth investigation of the proposed link between NLS1s and quasars by means of comparison of composite z 4 spectra and a principal component analysis; (4) a simulation of Seyferts/quasars designed to explore the role of dust in modifying their observed spectral energy distribution; and (5) a sensitive search for accretion signatures in a large sample of nearby emission-line galaxy nuclei, employing a quantitative comparison of the nebular line flux ratios in small (HST) and large (ground-based) apertures. The lowand high-redshift quasars are found to be very similar in their emission characteristics, although differences exist. In particular, the data bolster indications of supersolar metallicities in the luminous, sources, which supports z 4 scenarios that assume substantial star formation concurrent or preceding the quasar phenomena. An in-depth analysis of quasar selection effects is performed, based on comparisons of distributions of equivalent widths for quasar ensembles characterized by different detection techniques. The measurements are consistent with a common parent population, suggesting that the trends identified here are representative of high-z QSOs. The quasars are found to be more metal enriched and z 4 more spectroscopically heterogeneous than the NLS1s, indicating that a close connection between these objects remains doubtful. NLS1s reveal redder UV-blue continua than those measured in other quasars and Seyferts. The sources with UV line absorption are in general less powerful and show redder spectra, suggesting that luminosity-dependent dust absorption may be important in modifying their continua. A recedingtorus–like geometry seems to explain these trends and other observed correlations between quasar luminosity and continuum slope. This relatively simple framework also predicts a number of absorbed AGNs that is consistent with recent modeling and observations of the X-ray background light and extragalactic point source population. Finally, in most of the nearby emission-line nuclei, the expected increased AGN-like behavior at smaller scales is not seen, although the nuclear emission is resolved. This suggests that these sources are not necessarily powered by accretion onto a compact object and that the composite model proposed for the LINER/H ii transition nuclei (which assumes a central accreting-type nucleus surrounded by star-forming regions) is not generally supported. Only about 10% of the narrow-line objects reveal broad Ha features, thus changing their spectral classification from type 2 to type 1.
A One-Pot Cross-Pinacol Coupling/Rearrangement Procedure

A new catalytic retro-pinacol/cross-pinacol reaction, followed by subsequent rearrangement or deoxygenation of the intermediately formed vicinal diols, is described. This operationally simple one-pot protocol allows isolation of geminal α,α-diphenyl ketones or 1,1-diphenyl alkenes with high yields and selectivities.
Dynamics of Intra-EMS Interest Rate Linkages

Anumber of previous studies have questioned the dominant role of Germany within the European Monetary System (EMS). These conclusions are often based on empirical findings that the interest rates of EMS member countries are not affected by German interest rates, even in the long run. In this study, we demonstrate that intra-EMS interest rate differentials (vis-a-vis Germany) exhibit mean-reverting behavior characterized by long-memory dynamics. In a system incorporating six EMS countries and one non-EMS country (the U.S.A.), estimates from a fractional error correction model suggest the presence of short-run intra-EMS monetary-policy interdependencies but validate the German Dominance Hypothesis in the long run.