cssi/SciSciGPT-SciSciNet huggingface dataset:
Algebraic structures and eigenstates for integrable collective field theories

Conditions for the construction of polynomial eigen-operators for the Hamiltonian of collective string field theories are explored. Such eigen-operators arise for only one monomial potentialv(x)=μx 2 in the collective field theory. They form aw ∞-algebra isomorphic to the algebra of vertex operators in 2d gravity. Polynomial potentials of orders only strictly larger or smaller than 2 have no non-zero-energy polynomial eigen-operators. This analysis leads us to consider a particular potentialv(x)=μx 2+g/x 2. A Lie algebra of polynomial eigen-operators is then constructed for this potential. It is a symmetric 2-index Lie algebra, also represented as a subalgebra ofU(sl(2)).
Self-care Barriers Reported by Emergency Department Patients With Acute Heart Failure: A Sociotechnical Systems-Based Approach

Study objective We pilot tested a sociotechnical systems-based instrument that assesses the prevalence and nature of self-care barriers among patients presenting to the emergency department (ED) with acute heart failure. Methods A semistructured instrument for measuring self-reported self-care barriers was developed and administered by ED clinicians and nonclinician researchers to 31 ED patients receiving a diagnosis of acute heart failure. Responses were analyzed with descriptive statistics and qualitative content analysis. Feasibility was assessed by examining participant cooperation rates, instrument completion times, item nonresponse, and data yield. Results Of 47 distinct self-care barriers assessed, a median of 15 per patient were indicated as "sometimes" or "often" present. Thirty-four specific barriers were reported by more than 25% of patients and 9 were reported by more than 50%. The sources of barriers included the person, self-care tasks, tools and technologies, and organizational, social, and physical contexts. Seven of the top 10 most prevalent barriers were related to patient characteristics; the next 3, to the organizational context (eg, life disruptions). A preliminary feasibility assessment found few item nonresponses or comprehension difficulties, good cooperation, and high data yield from both closed- and open-ended items, but also found opportunities to reduce median administration time and variability. Conclusion An instrument assessing self-care barriers from multiple system sources can be feasibly implemented in the ED. Further research is required to modify the instrument for widespread use and evaluate its implementation across institutions and cultural contexts. Self-care barriers measurement can be one component of broader inquiry into the distributed health-related "work" activity of patients, caregivers, and clinicians.
Doppler Properties of Polyphase Coded Pulse Compression Waveforms

Doppler properties of the Frank polyphase code and the recently derived P1, P2, P3, and P4 polyphase codes are investigated and compared. An approximate 4 dB cyclic variation of the peak compressed signal is shown to occur as the Doppler frequency increases. The troughs in the peak-signal response occur whenever the total phase shift across the uncompressed pulse, due to Doppler, is an odd multiple of ? radians. It is shown that while the P3 and P4 codes have larger zero-Doppler peak sidelobes than the other codes, the P3 and P4 codes degrade less as the Doppler frequency increases. Also, the effects of amplitude weighting and receiver bandlimiting for both zero and nonzero Doppler are investigated.
Dynamics of self-propelled particles under strong confinement

We develop a statistical theory for the dynamics of non-aligning, non-interacting self-propelled particles confined in a convex box in two dimensions. We find that when the size of the box is small compared to the persistence length of a particle's trajectory (strong confinement), the steady-state density is zero in the bulk and proportional to the local curvature on the boundary. Conversely, the theory may be used to construct the box shape that yields any desired density distribution on the boundary, thus offering a general tool to understand and design such confinements. When the curvature variations are small, we also predict the distribution of orientations at the boundary and the exponential decay of pressure as a function of box size recently observed in simulations in a spherical box.
FROM FLAG COMPLEXES TO BANNER COMPLEXES

A notion of an $i$-banner simplicial complex is introduced. For various values of $i$, these complexes interpolate between the class of flag complexes and the class of all simplicial complexes. Examples of simplicial spheres of an arbitrary dimension that are $(i+1)$-banner but not $i$-banner are constructed. It is shown that several theorems for flag complexes have appropriate $i$-banner analogues. Among them are (1) the codimension-$(i+j-1)$ skeleton of an $i$-banner homology sphere $\Delta$ is $2(i+j)$-Cohen--Macaulay for all $0\leq j\leq \dim\Delta+1-i$, and (2) for every $i$-banner simplicial complex $\Delta$ there exists a balanced complex $\Gamma$ with the same number of vertices as $\Delta$ whose face numbers of dimension $i-1$ and higher coincide with those of $\Delta$.
Turbulent natural convection of liquid deuterium, hydrogen and nitrogen within enclosed vessels

Abstract Quasi-steady natural convection of liquid deuterium, hydrogen, and nitrogen within a sphere, hemisphere, horizontal cylinder, and vertical cylinder has been studied experimentally for the case of a nearly uniform wall temperature. A single expression relating the Nusselt and Rayleigh numbers, Nu = 0·104Ra0·352, fits the deuterium and nitrogen data over the range 7 × 108
Alkylation of thiols with trichloroacetimidates under neutral conditions

Abstract Trichloroacetimidates are displaced with thiols to form the corresponding sulfides without the need for an added acid or base by simply heating the reactants in refluxing THF. This operationally simple procedure provides the corresponding sulfides in excellent yields with only the formation of the neutral trichloroacetamide as the side product. The imidate may also be formed in situ, allowing for a direct method for the formation of sulfides from alcohols. This reaction provides a general method for the synthesis of a variety of sulfides from inexpensive and readily available alcohol starting materials.
FINITE QUANTUM FLUCTUATIONS ABOUT STATIC FIELD CONFIGURATIONS

Abstract We develop an unambiguous and practical method to calculate one-loop quantum corrections to the energies of classical time-independent field configurations in renormalizable field theories. We show that the standard perturbative renormalization procedure suffices here as well. We apply our method to a simplified model where a charged scalar couples to a neutral “Higgs” field, and compare our results to the derivative expansion.
QUARK FOCUSING AT HADRONIC VERTICES.

A basis for dual theory of processes that involve external and/or intermediate exotic hadrons is found in the form of a quark-focusing principle. This principle, derived from the conformal invariance of the theory, requires that at a hadronic vertex all active quarks be focused to a point of their world sheet and act together (as a point-like particle) in the transfer of momentum. It is found that all hadronic couplings (including the coupling of any three exotic hadrons) can be expressed in terms of a single (say the ρππ) coupling constant. Applications to BB scattering are made.
A mathematical model for the vulnerable phase in myocardium

Abstract We present a model of excitable media with the feature that it has a vulnerable phase during which a premature current stimulus will result in the formation of a reentrant self-sustained wave of excitation. The model exploits anisotropic coupling of identical cells, and is therefore useful as a model for the myocardium. We discuss why there is a vulnerable phase and how to determine it quantitatively in models of excitable media, and we demonstrate numerically that permanently rotating waves are formed when a stimulus is applied during this vulnerable phase. Finally, it is shown that the direction of fastest propagation in myocardium is not necessarily the direction of highest safety factor, contrary to commonly accepted opinion. As a result, a reentrant wave is formed after a stimulus is blocked in the axial direction and successfully propagates away from the stimulus site in the lateral direction.
A PHENOMENOLOGICAL MODEL OF SUBCOOLED FLOW BOILING IN THE DETACHED BUBBLE REGION

Abstract The Weisman-Illeslamlou model for the critical heat flux in subcooled boiling has been extended to the determination of boiling heat fluxes throughout the detached bubble region. Both the original model and its extension are based on the assumption that turbulent interchange at the edge of the bubbly layer on the heated wall is the limiting process. By recognizing that the turbulent intensity at the bubbly layer edge is a function of the bubbly layer void fraction, the relationship between heat flux and bubbly layer quality can be established. The bubbly layer quality so obtained allows the computation of the fraction of heat transferred by boiling. With the additional assumption that the wall temperature and boiling heat flux are uniquely related, the wall temperature may be calculated. The boiling curves obtained are shown to be in reasonable agreement with data for subcooled boiling of refrigerant 113 in round tubes. The extended theory is also shown to provide predictions of the onset of the detached bubble region.
Dynamics of solid dispersions in oil during the lubrication of point contacts. I - Graphite

A Hertzian contact is lubricated with dispersed graphite in mineral oils under boundary lubrication conditions. The contacts are optically observed under pure rolling, combined rolling and sliding, and pure sliding conditions. The contact is formed with a steel ball on the flat surface of a glass disk. Photomicrographs are presented which show the distribution of the graphite in and around the contact. In addition, friction and surface damage are shown for conditions when the base oils are used alone and when graphite is added to the base oils. Under pure rolling and combined rolling and sliding conditions, it is found that, for low speeds, a graphite film can form which will separate the contacting surfaces. In contrast, under pure sliding conditions, graphite accumulates at the inlet and sweeps around the contact, but very little of graphite passes through the contact. The accumulated graphite appears to act as a barrier which reduces the supply of oil available to the contact for boundary lubrication. ...
The Spatial Structure of an Accretion Disk

Based on the microlensing variability of the two-image gravitational lens HE 1104-1805 observed between 0.4 and 8 μm, we have measured the size and wavelength-dependent structure of the quasar accretion disk. Modeled as a power law in temperature, T ∝ R−β, we measure a B-band (0.13 μm in the rest frame) half-light radius of R1/2,B = 6.7+ 6.2−3.2 × 1015 cm (68% confidence level) and a logarithmic slope of β = 0.61+ 0.21−0.17 (68% confidence level) for our standard model with a logarithmic prior on the disk size. Both the scale and the slope are consistent with simple thin disk models where β = 3/4 and R1/2,B = 5.9 × 1015 cm for a Shakura-Sunyaev disk radiating at the Eddington limit with 10% efficiency. The observed fluxes favor a slightly shallower slope, β = 0.55+ 0.03−0.02, and a significantly smaller size for β = 3/4.
The efficient calculation of powers of polynomials

Suppose we are given a polynomial P(x"1,...,x"r) in r>=1 variables, let m bound the degree of P in all variables x"i, [email protected][email protected]?r, and we wish to raise P to the nth power, n>1. In a recent paper which compared the iterative versus the binary method it was shown that their respective computing times were O(m^2^rn^r^+^1) versus O(mn)^2^r) when using single precision arithmetic. In this paper a new algorithm is given whose computing time is shown to be O((mn)^r^+^1). Also if we allow for polynomials with multiprecision integer coefficients, the new algorithm presented here will be faster by a factor of m^r^-^1n^r over the binary method and faster by a factor of m^r^-^1 over the iterative method. Extensive empirical studies of all three methods show that this new algorithm will be superior for polynomials of even relatively small degree, thus guaranteeing a practical as well as a useful result.
Approximate inversion of the Black–Scholes formula using rational functions

Abstract The Black–Scholes formula is often used in the backward direction to invert the implied volatility, usually with some solver method. Solver methods, being aesthetically unappealing, are also slower than closed-form approximations. However, closed-form approximations in previous works lack accuracy, often providing option pricing errors well exceeding the bid–ask spreads. We develop a new closed-form method based on the rational approximation. The rational approximation is much faster than typical solver methods and very accurate for both at-the-money and away-from-the-money options. Its accuracy can be further improved by one or two steps of Newton–Raphson iterations.
The first enantioselective syntheses of pure R- and S-isoproterenol

Abstract An efficient and highly selective synthetic route to either R - or S -isoproterenol ( 1 ) is described which employs a robot-like catalytic molecule to establish chirality, and readily provides these important therapeutic agents in enantiomerically pure form.
The interaction of steroids with liver microsomal cytochrome P-450--a general hypothesis.

Abstract The study of the oxidative metabolism of steroids as catalyzed by cytochrome P-450 offers a unique challenge to our understanding of critically important biochemical events in a wide variety of areas of investigation. The approaches currently used in our laboratory are to better define (1) the milieu of the heme iron of cytochrome P-450 for the binding of the substrate and (2) the potential role of organic peroxides as key intermediates in oxygen activation by cytochrome P-450. The present report, although highly speculative, hopefully will stimulate others to expand further and test the hypotheses presented, i.e. the role of steering groups on the substrate molecule which orient the substrate to facilitate hydroxylation at specific sites and the presence of higher valence states for the heme iron-substrate complex of cytochrome P-450 associated with oxygen activation prior to substrate hydroxylation.
Silyl-substituted cyclopropyl carbenoids

Cyclopropyl carbeniods, generated from dibromocyclopropanes and methyllithium, insert preferentially into SiMe3 activated CH bonds. In other cases, allene formation remains the dominant process.
Asymmetric additions to dichlorophenyldioxane, a new chiral acetal

Abstract 4-(2,6-Dichlorophenyl)-1,3-dioxanes have been reacted with weak nucleophiles and TiCl 4 to give benzyl ethers with high selectivity. The major products are consistent with an SN 2 -like mechanism. The benzyl ether is removed in one step using Li/NH 3 to give non-racemic secondary alcohols.
Assessing rare and delayed side-effects of contraceptive steroids.

Abstract Rare side effects pose special problems for detection by virtue of their low incidence or unusual nature. They are often missed in initial clinical trials due to their low frequency of occurrence and are only picked up after widespread usage of the contraceptive agent. Rare side effects are usually brought to attention by voluntary spontaneous reporting, occasionally by means of intensive monitoring systems. Once suspected, their rarity makes an initial prospective study infeasible but retrospective investigations can be conducted with less expenditure of time and resources. If warranted, prospective studies can later be initiated to further quantitate and verify the findings of the retrospective investigations. The advantages and disadvantages of retrospective and prospective studies are discussed. In order to determine if contraceptive steroids affect subsequent fertility, a prospective study is most desirable as the temporal relations between pill taking and conception must be obtained in great detail. Some of the problems in the design of such an investigation are elaborated.
Loop variables and the Virasoro group

Abstract We derive an expression in closed form for the action of a finite element of the Virasoro group on generalized vertex operators. This complements earlier results giving an algorithm to compute the action of a finite string of generators of the Virasoro algebra on generalized vertex operators. The main new idea is to use a first order formalism to represent the infinitesimal group element as a loop variable. To obtain a finite group element it is necessary to thicken the loop to a band of finite thickness. This technique makes the calculation very simple.
A versatile synthesis of substituted benzimidazolium salts by an amination/ ring closure sequence

[reaction: see text]. A new method to produce benzimidazolium salts based on a successive Buchwald-Hartwig amination and ring closure is reported. A variety of different benzimidazolium salts can be prepared using this procedure. Amines that bear an alpha-chiral group undergo the reaction to furnish chiral benzimidazolium salts. The salts that lack a C2 substituent on the heterocycle are readily deprotonated to give nucleophilic carbenes.
Unsteady Influences in Droplet Dynamics and Combustion

Abstract This research investigation addresses the problem of the unsteady dynamics associated with the vaporization. ignition and hurning of hydrocarhon fuel droplets in laminar and turhulent flowfields. The method of approach is numerical. and detailed solutians of the Navier-Stokes equations have heen carried out to determine the important physical processes which occur around a burning droplet. For the relatively high pressure conditions of the present problem the most unsteady feature of the flow was the ignition and flame formation process. The ignition process causes major changes in the drag and heat transfer compared to the influences of eddy turhulence or the natural decay of the frecstream velocity between the droplet and the surroundings. However, both eddy turbulence and the natural decay of the freestream velocity play a very important role in the history over the droplet lifetime. All of the flow processes comhine to cause the trajectory or the history of the droplet to he much different th...
Multi-anvil, high pressure apparatus: a half-century of development and progress

H. Tracy Hall and the cubic-anvil apparatus which he developed at Brigham Young University to produce diamonds without the belt apparatus. [Courtesy of the H. Tracy Hall Foundation]. In 1958, Tracy Hall invented the first multi-anvil, high pressure apparatus: a tetrahedral-anvil device capable of attaining simultaneous pressures of 10 GPa and temperatures above 3000 K. In the past half-century, multi-anvil apparatus (MAA) have evolved progressively and can now reach pressures close to 100 GPa at high temperatures. Many of these high pressure devices have been utilized in conjunction with in situ X-ray diffraction, especially with the advent of synchrotron radiation facilities in the early 1980s. There are a variety of technological approaches to generating high pressures in the laboratory, primarily motivated by the desire to study the behavior of materials at elevated pressures and temperatures; many of these approaches have been developed in the Earth science community due to the desire to replicate in ...
A Linear Amplifier Suitable for High Counting Rates

A linear amplifier suitable for high counting rates is described. The amplifier uses double-delay-line shaping to minimize base line shifts and to enable timing signals to be obtained from the zero crossover. Miniature delay lines are used and the amplifier is designed to work with lines as short as 100 nanoseconds. It has a maximum gain of 500 and a rise time of 18 nanoseconds. To minimize delay line reflections, the lines are terminated at both ends. A novel circuit is used to obtain the delay line shaping. The amplifier has good overload characteristics and is constructed very compactly. It plugs into a frame designed to accomodate a series of compatible circuits of modular design. The front panel space required is 3.6 by 7 inches. Circuitry and performance are described.
Test ideals in diagonal hypersurface rings, II

Abstract Let R = k [ x 1 ,…, x n ]/( x 1 d +⋯+ x n d ), where k is a field of characteristic p , p does not divide d and n ⩾3. We describe a method for computing the test ideal for these diagonal hypersurface rings. This method involves using a characterization of test ideals in Gorenstein rings as well as developing a way to compute tight closures of certain ideals despite the lack of a general algorithm. In addition, we compute examples of test ideals in diagonal hypersurface rings of small characteristic (relative to d ) including several that are not integrally closed. These examples provide a negative answer to Smith's question [K.E. Smith, The multiplier ideal is universal test ideal, Comm. Algebra 28 (12) (2000) 5912–5929] of whether the test ideal in general is always integrally closed.
Distortions in world food markets in the wake of GATT: Evidence and policy implications

Abstract Although the principle of trade liberalization has gained wide acceptance in recent years, many policy makers in developing countries, especially in Latin America, are exploring temporary import restrictions in the form of additional tariff protection to insulate domestic farmers from the impact of depressed prices until the Uruguay Round accord leads to higher world market prices for agricultural products. The paper argues that there is little reason to believe that current world market prices will rise substantially in real terms, even with the Uruguay Round accord fully implemented. This finding suggests that additional tariff protection would not make economic sense.
Recent developments in monoamine histochemistry.

Publisher Summary This chapter discusses the recent developments in the formaldehyde fluorescence technique of Falck and Hillarp to study monoamine histochemistry. With the routine procedure of the Falck–Hillarp technique, that is treatment of freeze dried tissues with formaldehyde vapors, it is extremely difficult to visualize very fine noradrenaline nerve terminals such as those present in cortical areas. Furthermore, the dopamine (DA), nerve terminals, for example, in the neostriatum do not appear as distinct dot-like fluorescent structures but as a diffuse fluorescence indicating a diffusion of the amines out of the nerve endings during the processing procedures. This technique has recently been improved6 by the introduction of glyoxylic acid, which can be used instead of formaldehyde at the perfusion and partly also at the vapour reaction step. The latter procedure is advantageous especially for the visualization of DA. Moreover, the combination of different histochemical techniques, for example, formaldehyde fluorescence with immunofluoresence, performed either on consecutive sections or on the same section, may be valuable for studying the morphological interrelationships between various neuron systems.
Supported metal catalysts prepared from bimetallic clusters: ReOs3 clusters on γ-Al2O3

Abstract Supported metal catalysts were prepared by the reaction of H 3 ReOs 3 (CO) 13 with the surface of γ-Al 2 O 3 . After treatment of the sample in He or in H 2 followed by treatment in H 2 , the Os was present in the metallic state as small crystallites, and Re was present in higher oxidation states, which were controlled by the pretreatment. Re in a high oxidation state (approximately + 7), resulting from the former pretreatment, did not affect the catalytic performance of the Os for hydrogenolysis of n -butane, but Re in a lower oxidation state (approximately + 2 or + 3), resulting from the latter pretreatment, doubled the activity of the catalyst and increased its resistance to deactivation. The results point the way to control of the structure and properties of catalysts by manipulation of the surface organometallic chemistry.
Spectroscopic studies on the TiCl4-promoted reaction of allylsilanes with aldehydes and α,β-enones

Abstract The complexation of n-heptanal and 4-(n-heptyl)benzaldehyde with TiCl 4 was studied spectroscopically. It was observed that the nature of the complex formed was dependent upon the stoichiometry of TiCl 4 present. The 2:1 (Lewis base /TiCl 4 ) complex was preferred at sub-stoichiometric quantities of TiCl 4 while the 1:1 complex formed preferentially when excess TiCl 4 was present. Reaction of the pre-complexed aldehyde with allyltrimethylsilane led to the formation of a titanium alkoxide, the structure of which was independently established by metathesis of the corresponding silyl ether. No metathesis of the allylsilane occurred before addition. The reaction of allyltrimethylsilane with TiCl 4 -complexed enones was also studied. A titanium enolate was observed spectroscopically as the intermediate in this reaction. No metathesis of the allylsilane occurred before addition to the complexed enone.
Short Gamma-Ray Bursts with Extended Emission

The recent association of several short gamma-ray bursts (GRBs) with early type galaxies with low star formation rate demonstrates that short bursts arise from a different progenitor mechanism than long bursts. However, since the duration distributions of the two classes overlap, membership is not always easily established. The picture is complicated by the occasional presence of softer, extended emission lasting tens of seconds after the initial spike- like emission comprising an otherwise short burst. Using the large BATSE sample with time-tagged event (TTE) data, we show that the fundamental defining characteristic of the short burst class is that the initial spike exhibits negligible spectral evolution at energies above approx. 25 keV. This is behavior is nearly ubiquitous for the 260 bursts with T(sub 90) less than 2s where the BATSE TTE data type completely included the initial spike: Their spectral lags measured between the 25-50 keV and 100-300 energy ranges are consistent with zero in 90-95% of the cases, with most outliers probably representing the tail of the long burst class. We also analyze a small sample of "short" BATSE bursts - those with the most fluent, intense extended emission. The same lack of evolution on the pulse timescale obtains for the extended emission in the brighter bursts where significant measurements can be made. One possible inference is that both emission components may arise in the same region. We also show that the dynamic range in the ratio of peak intensities, spike : extended, is at least approx. l0(exp 3), and that for some bursts, the extended emission is only a factor of 2-5 lower. However, for our whole sample the total counts fluence of the extended component equals or exceeds that in the spike by a factor of several.
IMPORTANT LESSONS FROM STUDYING THE CHINESE ECONOMY

In 1979 the United States and China established normal diplomatic relations, allowing me to visit China and study the Chinese economy. After doing so for 30 years since and advising the government of Taiwan in the 1960s and the 1970s and the government of the People's Republic of China in the 1980s and the 1990s, this is an opportune moment for me to summarize the important lessons I have learned. The lessons will be summarized in four parts: on economic science, on formulating economic policy and providing economic advice, on the special characteristics of the Chinese economy and on the experience of China's economic reform. At the beginning, I should comment on the quality of Chinese official data on which almost all quantitative studies referred to in this article were based. Chow (2006) has presented the view that by and large the official data are useful and fairly accurate. The main justification is that every time I tested an economic hypothesis or estimated an economic relation using the official data the result confirmed the well-established economic theory. It would be a miracle if I had the power to make the Chinese official statisticians fabricate data to support my hypotheses. Even if I had had the power, most of the data had already been published for years before I conceived the ideas of the studies reported in this article.
On the Disruption of Star Clusters in a Hierarchical Interstellar Medium

The distribution of the number of clusters as a function of mass M and age T suggests that clusters get eroded or dispersed in a regular way over time, such that the cluster number decreases inversely as an approximate power law with T within each fixed interval of M. This power law is inconsistent with standard dispersal mechanisms such as cluster evaporation and cloud collisions. In the conventional interpretation, it requires the unlikely situation where diverse mechanisms stitch together over time in a way that is independent of environment or M. Here, we consider another model in which the large-scale distribution of gas in each star-forming region plays an important role. We note that star clusters form with positional and temporal correlations in giant cloud complexes, and suggest that these complexes dominate the tidal force and collisional influence on a cluster during its first several hundred million years. Because the cloud complex density decreases regularly with position from the cluster birth site, the harassment and collision rates between the cluster and the cloud pieces decrease regularly with age as the cluster drifts. This decrease is typically a power law of the form required to explain the mass-age distribution. We reproduce this distribution for a variety of cases, including rapid disruption, slow erosion, combinations of these two, cluster-cloud collisions, cluster disruption by hierarchical disassembly, and partial cluster disruption. We also consider apparent cluster mass loss by fading below the surface brightness limit of a survey. In all cases, the observed log M-log T diagram can be reproduced under reasonable assumptions.
On the Selection of Photometric Planetary Transits

We present a new method for differentiating between planetary transits and eclipsing binaries on the basis of the presence of ellipsoidal light variations. These variations can be used to detect stellar secondaries with masses of ~0.2 M☉ orbiting Sun-like stars at a photometric accuracy level that has already been achieved in transit surveys. By removing candidates exhibiting this effect, it is possible to greatly reduce the number of objects requiring spectroscopic follow-up with large telescopes. Unlike the usual candidate selection methods, which are based primarily on the estimated radius of the orbiting object, this technique is not biased against bona fide planets and brown dwarfs with large radii because the amplitude of the effect depends on the transiting object's mass and orbital distance. In many binary systems where a candidate planetary transit is actually due to the partial eclipse of two normal stars, the presence of flux variations due to the gravity darkening effect will show the true nature of these systems. We show that many of the recent OGLE III photometric transit candidates exhibit the presence of significant variations in their light curves and are likely to be due to stellar secondaries. We find that the light curves of white dwarf transits generally will not mimic those of small planets because of significant gravitationally induced flux variations. We discuss the relative merits of methods used to detect transit candidates that are due to stellar blends rather than planets. We outline how photometric observations taken in two bands can be used to detect the presence of stellar blends.
Electronic Markets and Trading Algorithms

Academics attempt to understand the consequences of fragmentation, electronic markets, and trading algorithms. Practitioners, by necessity, devise ever-improving trading algorithms to achieve their trading objectives. This article is a bridge of sorts. The author uses the structural approach developed throughout decades of research on price formation to illuminate modern electronic-trading practices and algorithms. He argues that despite the constantly changing trading landscape driven by tech nology improvements, the economic trade-offs embedded in trading algorithms are, for all intents and purposes, not different from manual trading. All that has changed is the implementation.
Solid-state NMR for bacterial biofilms

Bacteria associate with surfaces and one another by elaborating an extracellular matrix to encapsulate cells, creating communities termed biofilms. Biofilms are beneficial in some ecological niches, but also contribute to the pathogenesis of serious and chronic infectious diseases. New approaches and quantitative measurements are needed to define the composition and architecture of bacterial biofilms to help drive the development of strategies to interfere with biofilm assembly. Solid-state NMR is uniquely suited to the examination of insoluble and complex macromolecular and whole-cell systems. This article highlights three examples that implement solid-state NMR to deliver insights into bacterial biofilm composition and changes in cell-wall composition as cells transition to the biofilm lifestyle. Most recently, solid-state NMR measurements provided a total accounting of the protein and polysaccharide components in the extracellular matrix of an E. coli biofilm and transform our qualitative descriptions of matrix composition into chemical parameters that permit quantitative comparisons among samples. We present additional data for whole biofilm samples (cells plus the extracellular matrix) that complement matrix-only analyses. The study of bacterial biofilms by solid-state NMR is an exciting avenue ripe with many opportunities and we close the article by articulating some outstanding questions and future directions in this area.
Frobenius Problem and the Covering Radius of a Lattice

Let $N \geq2$ and let $1 < a_1 < \cdots < a_N$ be relatively prime integers. The Frobenius number of this N-tuple is defined to be the largest positive integer that cannot be expressed as $\sum_{i=1}^N a_i x_i {\rm where\ } x_1,\ldots,x_N$ are non-negative integers. The condition that $\gcd(a_1,\ldots,a_N)=1$ implies that such a number exists. The general problem of determining the Frobenius number given N and $a_1,\ldots,a_N$ is NP-hard, but there have been a number of different bounds on the Frobenius number produced by various authors. We use techniques from the geometry of numbers to produce a new bound, relating the Frobenius number to the covering radius of the null-lattice of this N-tuple. Our bound is particularly interesting in the case when this lattice has equal successive minima, which, as we prove, happens infinitely often.
A method for the selective oxidation of 1,4-diols to lactols

Abstract Solutions of o-iodoxybenzoic acid in dimethyl sulfoxide at 23 °C effect the highly selective oxidation of a number of 1,4-bisprimary or 1,4-primary-secondary diols to γ-lactols, permitting a conversion which could not previously be accomplished in one step.
A new synthesis of sucrose 6′-phosphate

Sucrose 6'-phosphate (3) is the key intermediate for sucrose (1) synthesis in plants [1]. It has recently become commercially available at ca. $1500/g (Sigma). The only chemical synthesis is that of Buchanan et al. [2]. This six-step procedure, while unambiguous, gives an overall yield of only ca. 6%. We describe here a simplified route (2 steps) with an unoptimized yield of ca. 15%. Our strategy was to use a phosphorylation reagent selective for primary hydroxyl groups and thus to avoid the necessity for blocking all of the secondary ones. Sowa and Ouchi [3] described a suitable system which they used very effectively for the synthesis of 5'-nucleotides from unprotected nucleosides. We applied this reagent to 2,1':4,6-di-O-isopropylidenesucrose (2) [4] in which the only unprotected primary hydroxyl group is that at the 6'-position (Scheme 1). The identity of the product was established by comparison of its rotation with the literature value and by the correspondence of its 1H and 13C NMR spectra with those of an authentic sample synthesized by Buchanan's method (Sigma) 1H assignments were made with the help of the assignments of du Penhoat et al. [5] for sucrose and the results of a one-bond H-C COSY experiment (Fig. 1). The 13C spectrum showed that all of the resonances were shifted downfield by ca. 0.5 ppm as compared with sucrose [6] except for the C-5' doublet which was shifted upfield by 0.5 ppm and the C-6' doublet which was shifted downfield by 2.2 ppm (Table 1).
Nonlinear model-based control of a batch reactive distillation column

Abstract The inherent trade off between model accuracy and computational tractability for model-based control applications is addressed in this article by the development of reduced order nonlinear models. Traveling wave phenomena is used to develop low order models for multicomponent reactive distillation columns. A motivational example of batch esterification column is used to demonstrate the synthesis procedure. Tight control of the column is obtained with the use of reduced model in a model predictive control algorithm.
Linearizing intuitionistic implication

Abstract An embedding of the implicational propositional intuitionistic logic (IIL) into the nonmodal fragment of intuitionistic linear logic (IMALL) is given. The embedding preserves cut-free proofs in a proof system that is a variant of IIL. The embedding is efficient and provides an alternative proof of the PSPACE-hardness of IMALL. It exploits several proof-theoretic properties of intuitionistic implication that analyze the use of resources in IIL proofs.
One-bit algorithms

Many algorithms in distributed systems assume that the size of a single message depends on the number of processors. In this paper, we assume in contrast that messages consist of a single bit. Our main goal is to explore how the one-bit translation of unbounded message algorithms can be sped up by pipelining. We consider two problems. The first is routing between two processors in an arbitrary network and in some special networks (ring, grid, hypercube). The second problem is coloring a synchronous ring with three colors. The routing problem is a very basic subroutine in many distributed algorithms; the three coloring problem demonstrates that pipelining is not always useful.
Disks from the perspective of a file system

Most applications do not deal with disks directly, instead storing their data in files in a file system, which protects us from those scoundrel disks. After all, a key task of the file system is to...
Temperature scales of magnetization oscillations in an asymmetric quantum dot

The temperature scales of different types of magnetization oscillations in a quantum dot, formed in a two-dimensional electron gas by circularly symmetric or asymmetric confining potentials, are studied. Aharonov-Bohm (AB) oscillations, with a superimposed fine structure caused by magnetic-field-induced shifts of the electronic energy levels, develop at low magnetic fields ${\ensuremath{\omega}}_{c}\ensuremath{\ll}{\ensuremath{\omega}}_{x,y}$ (where ${\ensuremath{\omega}}_{c}$ is the cyclotron frequency and ${\ensuremath{\omega}}_{x,y}$ are the harmonic confining frequencies that determine the shape and effective size of the dot). The characteristic scale of the fine-structure fluctuations is ${\ensuremath{\varphi}}_{0}/({\ensuremath{\varepsilon}}_{F}/\ensuremath{\Elzxh}{\ensuremath{\omega}}_{0})$ (where ${\ensuremath{\varphi}}_{0}$ is the flux quantum, ${\ensuremath{\varepsilon}}_{F}$ is the Fermi energy, and ${\ensuremath{\omega}}_{0}=\sqrt{{\ensuremath{\omega}}_{x}{\ensuremath{\omega}}_{y}})$ and they are smeared at temperatures $Tg(\ensuremath{\Elzxh}{\ensuremath{\omega}}_{0}{)}^{2}/{\ensuremath{\varepsilon}}_{F},$ with restoration of the pure AB picture for $Tl~\ensuremath{\Elzxh}{\ensuremath{\omega}}_{0}.$ At high magnetic fields, ${\ensuremath{\omega}}_{c}\ensuremath{\gg}{\ensuremath{\omega}}_{x,y},$ de Haas--van Alphen oscillations develop (for $Tl~\ensuremath{\Elzxh}{\ensuremath{\omega}}_{c}),$ with a superimposed AB oscillatory structure which undergoes temperature smearing for $Tg~\ensuremath{\Elzxh}{\ensuremath{\omega}}_{0}({\ensuremath{\omega}}_{0}/{\ensuremath{\omega}}_{c}).$ Effects of the asymmetry of the confining potential on the magnetization oscillations are discussed. The magnetic moment of the dot as a function of the chemical potential exhibits a series of paramagnetic peaks superimposed on a diamagnetic background, and the influence of the magnetic-field strength and asymmetry of the dot on these features is discussed.
The GOES-R GeoStationary Lightning Mapper (GLM)

Abstract The Geostationary Operational Environmental Satellite R-series (GOES-R) is the next block of four satellites to follow the existing GOES constellation currently operating over the Western Hemisphere. Advanced spacecraft and instrument technology will support expanded detection of environmental phenomena, resulting in more timely and accurate forecasts and warnings. Advancements over current GOES capabilities include a new capability for total lightning detection (cloud and cloud-to-ground flashes) from the Geostationary Lightning Mapper (GLM), and improved cloud and moisture imagery with the 16-channel Advanced Baseline Imager (ABI). The GLM will map total lightning activity continuously day and night with near-uniform storm-scale spatial resolution of 8 km with a product refresh rate of less than 20 s over the Americas and adjacent oceanic regions in the western hemisphere. This will aid in forecasting severe storms and tornado activity, and convective weather impacts on aviation safety and efficiency. In parallel with the instrument development, an Algorithm Working Group (AWG) Lightning Detection Science and Applications Team developed the Level 2 (stroke and flash) algorithms from the Level 1 lightning event (pixel level) data. Proxy data sets used to develop the GLM operational algorithms as well as cal/val performance monitoring tools were derived from the NASA Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) instruments in low Earth orbit, and from ground-based lightning networks and intensive prelaunch field campaigns. The GLM will produce the same or similar lightning flash attributes provided by the LIS and OTD, and thus extend their combined climatology over the western hemisphere into the coming decades. Science and application development along with preoperational product demonstrations and evaluations at NWS forecast offices and NOAA testbeds will prepare the forecasters to use GLM as soon as possible after the planned launch and checkout of GOES-R in late 2015. New applications will use GLM alone, in combination with the ABI, or integrated (fused) with other available tools (weather radar and ground strike networks, nowcasting systems, mesoscale analysis, and numerical weather prediction models) in the hands of the forecaster responsible for issuing more timely and accurate forecasts and warnings.
Facile Synthesis of Highly Functionalized N-Methyl Amino Acid Esters without Side-Chain Protection

[reaction: see text] The facile, two-pot synthesis of N-methyl amino acid esters by way of reductive amination is presented. Side chain protection schemes are not required, the starting materials are all commercially available, and the synthetic method is straightforward and affords desired product in very high yield.
An efficient synthesis of (R)-3-hydroxytetradecanoic acid

Abstract A short, efficient synthesis of (R)-3-hydroxytetradecanoic acid, a key component of bacterial endotoxins, using (R)-oxirane acetic acid ethyl ester as the source of chirality is described. The method is general and can be used in the preparation of other chiral 3-hydroxy acids.
Monitoring Java Programs with Java PathExplorer

Abstract We present recent work on the development of Java PathExplorer (JP a X), a tool for monitoring the execution of Java programs. JPaX can be used during program testing to gain increased information about program executions, and can potentially furthermore be applied during operation to survey safety critical systems. The tool facilitates automated instrumentation of a program's byte code, which will then emit events to an observer during its execution. The observer checks the events against user provided high level requirement specifications, for example temporal logic formulae, and against lower level error detection procedures, usually concurrency related such as deadlock and data race algorithms. High level requirement specifications together with their underlying logics are defined in rewriting logic using Maude, and then can either be directly checked using Maude rewriting engine, or be first translated to efficient data structures and then checked in Java.
Synthesis of oxides containing transition metals

Abstract Various techniques are described for the preparation of polycrystalline and single crystal samples of transition metal oxides. The importance of “precursors” in facilitating the formation of the desired product is discussed. The various problems encountered in the preparation of pure, homogeneous, uniform materials are related to the characterization of these compounds in order to properly describe their properties.
Construction of Non-Perturbative, Unitary Particle–Antiparticle Amplitudes for Finite Particle Number Scattering Formalisms

Starting from a unitary, Lorentz invariant two-particle scattering amplitude, we show how to use an identification and replacement process to construct a unique, unitary particle–antiparticle amplitude. This process differs from conventional on-shell Mandelstam s, t, u crossing in that the input and constructed amplitudes can be off-diagonal and off-energy shell. Further, amplitudes are constructed using the invariant parameters which are appropriate to use as driving terms in the multi-particle, multichannel non-perturbative, cluster decomposable, relativistic scattering equations of the Faddeev-type integral equations recently presented by Alfred, Kwizera, Lindesay and Noyes. It is therefore anticipated that when so employed, the resulting multi-channel solutions will also be unitary. The process preserves the usual particle–antiparticle symmetries. To illustrate this process, we construct a J=0 scattering length model chosen for simplicity. We also exhibit a class of physical models which contain a finite quantum mass parameter and are Lorentz invariant. These are constructed to reduce in the appropriate limits, and with the proper choice of value and sign of the interaction parameter, to the asymptotic solution of the non-relativistic Coulomb problem, including the forward scattering singularity, the essential singularity in the phase, and the Bohr bound-state spectrum.