cssi/SciSciGPT-SciSciNet huggingface dataset:
Magnetic Field Dependence of the Energy Gap in Superconductors

We calculate the reduction of the energy gap at zero temperature for a bulk superconductor in the presence of a static external magnetic field, to the second order in the field strength. Simple formulas are obtained for the long ($\ensuremath{\lambda}\ensuremath{\gg}{\ensuremath{\xi}}_{0}$) and short ($\ensuremath{\lambda}\ensuremath{\ll}{\ensuremath{\xi}}_{0}$) wavelength limits, where ${\ensuremath{\xi}}_{0}$ is the coherence length.We use the general gauge-invariant formulation of the Bardeen-Cooper-Schrieffer (BCS)-Bogoliubov theory developed by one of the authors, but the result is also shown to agree with that of the BCS variational procedure applied in the presence of the field. The gauge invariance is maintained by virtue of the collective excitations as in the Meissner effect. The mathematical proof of gauge invariance is carried out in a completely general manner using Ward identities.
A simple synthesis of 2-vinylindoles

Abstract A two step synthesis of 2-vinyl indoles is described. Reaction of the anions of 2-methylindole-3-carboxylates ( 1 ) and ( 5 ) with ketones and aldehydes leads directly to 2-vinylindole-3-carboxylic acids ( 3 ) and esters ( 7 ), respectively. Decarboxylation of the acids ( 3 ) yields the desired 2-vinylindoles ( 4 ).
Expression-invariant face recognition in hyperspectral images

The performance of a face recognition system degrades when the expression in the probe set is different from the expression in the gallery set. Previous studies use either spatial or spectral information to address this problem. We propose an algorithm that uses spatial and spectral information for expression-invariant face recognition. The algorithm uses a set of three-dimensional Gabor filters to exploit spatial and spectral correlations, while principal-component analysis is used to model expression variation. We demonstrate the effectiveness of the algorithm on a database of 200 subjects with neutral and smiling expressions and explore the dependence of the performance on image spatial resolution and training set size.
Growth Velocities of Branched Actin Networks

The growth of an actin network against an obstacle that stimulates branching locally is studied using several variants of a kinetic rate model based on the orientation-dependent number density of filaments. The model emphasizes the effects of branching and capping on the density of free filament ends. The variants differ in their treatment of side versus end branching and dimensionality, and assume that new branches are generated by existing branches (autocatalytic behavior) or independently of existing branches (nucleation behavior). In autocatalytic models, the network growth velocity is rigorously independent of the opposing force exerted by the obstacle, and the network density is proportional to the force. The dependence of the growth velocity on the branching and capping rates is evaluated by a numerical solution of the rate equations. In side-branching models, the growth velocity drops gradually to zero with decreasing branching rate, while in end-branching models the drop is abrupt. As the capping rate goes to zero, it is found that the behavior of the velocity is sensitive to the thickness of the branching region. Experiments are proposed for using these results to shed light on the nature of the branching process.
Reconciling semiclassical and Bohmian mechanics. I. Stationary states

The semiclassical method is characterized by finite forces and smooth, well-behaved trajectories, but also by multivalued representational functions that are ill behaved at caustics. In contrast, quantum trajectory methods—based on Bohmian mechanics (quantum hydrodynamics)—are characterized by divergent forces and erratic trajectories near nodes, but also well-behaved, single-valued representational functions. In this paper, we unify these two approaches into a single method that captures the best features of both, and in addition, satisfies the correspondence principle. Stationary eigenstates in one degree of freedom are the primary focus, but more general applications are also anticipated.
Changing relationship between the North Atlantic Oscillation and key North Atlantic climate parameters

[1] The North Atlantic Oscillation (NAO) is the key indicator of long-term variability in the North Atlantic. Numerous studies have accepted as a paradigm a steady relationship between the NAO and key North Atlantic climate parameters like the sea surface temperature (SST), surface air temperature (SAT), and sea level pressure (SLP). However, some studies suggest that this relationship is not always steady. For example, the recent decline of the Arctic ice cap is accompanied by a neutral or negative NAO index, whereas the ice decline observed over the last decades is associated with the positive NAO phase and with high atmospheric cyclonicity. In this study, we point to a lack of steadiness in the relationship between the NAO and SAT, SST, and SLP over the North Atlantic region when observed over long (decadal) time intervals. This suggests that the relationship is more complex than previously thought and may require further investigation.
A transposition rule analysis based on a particle process

A linear list is a collection of items that can be accessed sequentially. The cost of a request is the number of items that need to be examined before the desired item is located, i.e. the distance of the requested item from the beginning of the list. The transposition rule is one of the algorithms designed to reduce the search cost by organizing the list. In particular, upon a request for a given item, the item is transposed with the preceding one. We develop a new approach for analyzing the algorithm, based on a coupling to a certain constrained asymmetric exclusion process. This allows us to establish an asymptotic optimality of the rule for two families of request distributions.
Analog information processing at the quantum limit with a Josephson ring modulator

Amplifiers are crucial in every experiment carrying out a very sensitive measurement. However, they always degrade the information by adding noise. Quantum mechanics puts a limit on how small this degradation can be. Theoretically, the minimum noise energy added by a phase-preserving amplifier to the signal it processes amounts at least to half a photon at the signal frequency. Here we propose a practical microwave device that can fulfil the minimal requirements to reach the quantum limit. The availability of such a device is of importance for the readout of solid-state qubits, and more generally for the measurement of very weak signals in various areas of science. We discuss how this device can be the basic building block for a variety of practical applications, such as amplification, noiseless frequency conversion, dynamic cooling and production of entangled signal pairs. The minimum noise energy that a phase-preserving amplifier adds to the signal is fundamentally limited to half a photon. A proposed parametric amplifier based on Josephson junctions should be able to reach this limit at microwave frequencies.
Evaluation of (acyloxy)alkyl ester linkers for antibiotic release from siderophore–antibiotic conjugates

Abstract The syntheses of five ciprofloxacin-modified (acyloxyl)alkyl esters and two siderophore–ciprofloxacin conjugates based on enterobactin that harbor such hydrolyzable linkages are reported. The hydrolytic stabilities of ciprofloxacin-modified (acyloxy)alkyl esters, evaluated at pH 7.5 and 30 °C, vary by >370-fold depending on the substituents in the vicinity of the ester linkage.
A Chiral Ag-Based Catalyst for Practical, Efficient, and Highly Enantioselective Additions of Enolsilanes to α-Ketoesters

A Ag-based chiral catalyst promotes efficient and highly enantioselective aldol additions of ketone-derived enolsilanes to α-ketoesters in the presence of a readily available amino acid-based ligand and commercially available AgF2. α-Ketoester substrates may bear alkyl, alkenyl, and aryl substituents; reactions proceed to >98% conversion to afford the desired tertiary alcohols in 61−>98% isolated yield and 60−96% ee. In contrast to previously reported approaches, highest enantioselectivities are observed with sterically demanding substrates, and reactions can be carried out in undistilled solvent, in air with as little as 1 mol % catalyst.
A METHOD FOR OBTAINING SUSPENSIONS OF LIVING CELLS FROM THE FIXED TISSUES, AND FOR THE PLATING OUT OF INDIVIDUAL CELLS

Individual, living, tissue cells can be obtained in suspension by digesting with trypsin the clot of growing tissue cultures. Under these circumstances the living cells assume a spherical form. When washed and plated in fresh plasma they put out processes and proliferate. After growth in the new plates has occurred the digestion and plating can be repeated. The limits of the method have not yet been reached. We are at work on a number of the problems which it has opened up.
Major Basic Protein Homolog (MBP2): A Specific Human Eosinophil Marker

Human eosinophil granule major basic protein (MBP1) is an exceedingly basic (isoelectric point >11) 14-kDa protein, comprising the core of the secondary eosinophil granule. Recently, a less cationic homolog of MBP, termed MBPH or simply, MBP2, has been discovered. We prepared a panel of mAbs to MBP2 and used these Abs to localize and quantitate this molecule in leukocytes and biological fluids. Specific mAbs for MBP2 were selected using slot-blot analyses and used in a two-site immunoassay, Western blotting, and immunofluorescence microscopy. The sensitivity of the immunoassay was markedly improved by reduction and alkylation of MBP2. MBP1 is more abundant than MBP2 in lysates of eosinophils and their granules, as judged by immunoassay and Western blotting. By immunofluorescence, MBP1 is present in eosinophils, basophils, and a human mast cell line (HMC1), whereas MBP2 is only detected in eosinophils. Neither MBP1 nor MBP2 could be detected in any other peripheral blood leukocyte. MBP2 levels measured in plasma and serum were essentially identical. In contrast to past measurements for MBP1, MBP2 was not detected above normal levels in sera from pregnant donors. However, measurement of serum MBP2 discriminated patients with elevated eosinophils from normal subjects, and MBP2 was also detectable in other biological specimens, such as bronchoalveolar lavage, sputum, and stool. These results indicate that MBP2 is present only in eosinophils and that it may be a useful biomarker for eosinophil-associated diseases.
When is the Fourier transform of an elementary function elementary

Let F be a local field, $ \psi $ a nontrivial unitary additive character of F, and V a finite dimensional vector space over F. Let us say that a complex function on V is elementary if it has the form $ g(x) = C\psi(Q(x))\prod^{k}_{j = 1}\chi_j(P_j(x)), x \in V $ , where $ C \in \mathbb{C} $ , Q is a rational function (the phase function), $ P_j $ are polynomials, and $ \chi_j $ multiplicative characters of F. For generic $ \chi_j $ , this function canonically extends to a distribution on V (if char(F) = 0). Occasionally, the Fourier transform of an elementary function is also an elementary function (the basic example is the Gaussian integral: k = 0, Q is a nondegenerate quadratic form). It is interesting to determine when exactly this happens. This question is the main subject of our study. In the first part of this paper we show that for $ F = \mathbb{R} $ or $ \mathbb{C} $ , if the Fourier transform of an elementary function $ g \neq 0 $ with phase function -Q such that $ \det d^2Q \neq 0 $ is another elementary function $ g^* $ with phase function $ Q^* $ , then $ Q^* $ is the Legendre transform of Q (the "semiclassical condition"). We study properties and examples of phase functions satisfying this condition, and give a classification of phase functions such that both Q and $ Q^* $ are of the form f(x)/t, where f is a homogeneous cubic polynomial and t is an additional variable (this is one of the simplest possible situations). Unexpectedly, the proof uses Zak's classification theorem for Severi varieties.¶ In the second part of the paper we give a necessary and sufficient condition for an elementary function to have an elementary Fourier transform (in an appropriate "weak" sense) and explicit formulas for such Fourier transforms in the case when Q and $ P_j $ are monomials, over any local field F. We also describe a generalization of these results to the case of monomials of norms of finite extensions of F. Finally, we generalize some of the above results (including Fourier integration formulas) to the case when $ F = \mathbb{C} $ and Q comes from a prehomogeneous vector space.
Backward Scattering in the One-Dimensional Electron Gas

An exact solution to the one-dimensional electron gas with a particular attractive-interaction strength for scattering across the Fermi "surface" is given. It is shown that conductivity enhancement occurs for physically interesting values of the coupling constants. Scaling arguments are advanced to demonstrate that this solution applies generally for attractive backward scattering. In addition, the spinless problem is solved exactly for arbitrary couplings.
Synthesis of R- and S-3-Oxo-2-oxaspiro[4.4]-nonane-1-carboxylic acid.

Abstract An efficient synthesis and temperature dependent resolution of R- and S-3-Oxo-2-oxaspiro[4.4]-nonane-1-carboxylic acid are described. The assignment of absolute configuration is based on single crystal X-ray analysis of an amide derivative.
Treatment for Intracranial Dural Arteriovenous Malformations: A Meta-analysis from the English Language Literature

OBJECTIVE: The treatment of intracranial dural arteriovenous malformations (DAVMs) remains problematic. Options include ligature of feeding vessels, endovascular procedures, surgical obliteration, or a combination of the latter two. We conducted a meta-analysis of the English language literature on DAVMs to determine the most effective treatment option related to location and angiographic characteristics. METHODS: The criteria for inclusion were pre- and post-treatment angiography, a description of the type of treatment, and clinical outcome. The analysis included a total of 258 patients, 248 from a review of 223 published articles and 10 from the authors' series. DAVMs were divided into six categories by location, and the results of treatment were compared based on obliteration rates using X 2 analysis. RESULTS: In transverse-sigmoid sinus DAVMs (n = 64), combined therapy (endovascular plus surgical treatment) proved significantly more effective than either therapy alone (P < 0.01). For lesions of the tentorial incisura (n = 66), combined therapy and surgical obliteration alone proved superior to embolization (P < 0.001). For lesions of the cavernous sinus (n = 67), treatment was primarily endovascular, with success rates of 62 to 78% for transarterial and transvenous approaches, respectively. In the anterior fossa (n = 23), surgical obliteration was highly effective, with a success rate of 95 %. The small number of cases in both the superior sagittal sinus (n = 28) and middle fossa (n = 10) regions, precluded any statistical analysis. Finally, simple ligature of feeding vessels produced success rates of only 0 to 8% and can no longer be recommended. CONCLUSION: There is no single ideal treatment for the obliteration of DAVMs. The management of each case is best considered individually. The results of this review serve as a rational starting point for the selection of treatment options.
Time- and space-efficient randomized consensus

Abstract A protocol is presented which solves the randomized consensus problem [9] for shared memory. The protocol uses a total of O ( p 2 + n ) worst-case expected increment, decrement, and read operations on a set of three shared O (log n )-bit counters, where p is the number of active processors and n is the total number of processors. It requires less space than previous polynomial-time consensus protocols [6, 7]. and is faster when not all of the processors participate in the protocol. A modified version of the protocol yields a weak shared coin whose bias is guaranteed to be in the range 1/2 ± ϵ regardless of scheduler behavior, and which is the first such protocol for the shared-memory model to guarantee that all processors agree on the outcome of the coin.
Going Green to Stay in the Black: Transnational Capitalism and Renewable Energy

Sustainable energy use is rapidly developing, often with state support and patriotic political rhetoric. But the solar and wind energy industries are highly transnationalized and already inserted into global patterns of accumulation. While possibly solving some of the most pressing problems between capitalism and environmental sustainability, green capitalism still fails to address the contradiction between labor and capital. Therefore, any progressive strategy for social transformation must link the fair treatment of nature and labor together.
Effect of shear-layer control on leading-edge vortices

The effect of shear-layer control on leading-edge vortices over delta wings with sharp leading edges was investigated. By using suction near the separation point, the direction of the shear layer, and the location of the main vortex as well as its structure could be modified. The maximum swirl angle in the core and overall circulation decreased with suction. This caused the vortex breakdown location to move downstream. When the suction slot was located slightly inboard, the swirl angle was found to increase, causing the breakdown location to move upstream. It is shown that extremely small amounts of leadingedge suction can modify the location of the vortex core and can thus be used to induce rolling moment.
A characterization of strong approximation resistance

For a predicate f: {-1, 1}k ↦ {0, 1} with ρ(f) = |f-1(1)|/2k, we call the predicate strongly approximation resistant if given a near-satisfiable instance of CSP(f), it is computationally hard to find an assignment such that the fraction of constraints satisfied is outside the range [ρ(f) - Ω(1), ρ(f) + Ω(1)]. We present a characterization of strongly approximation resistant predicates under the Unique Games Conjecture. We also present characterizations in the mixed linear and semi-definite programming hierarchy and the Sherali-Adams linear programming hierarchy. In the former case, the characterization coincides with the one based on UGC. Each of the two characterizations is in terms of existence of a probability measure on a natural convex polytope associated with the predicate. The predicate is called approximation resistant if given a near-satisfiable instance of CSP(f), it is computationally hard to find an assignment such that the fraction of constraints satisfied is at least ρ(f) + Ω(1). When the predicate is odd, i.e. f(-z) = 1 - f(z), ∀z ∈ {-1, 1}k, it is easily observed that the notion of approximation resistance coincides with that of strong approximation resistance. Hence for odd predicates our characterization of strong approximation resistance is also a characterization of approximation resistance.
A Proposal for Quoting Money Market Rates

U.S. money market interest rates may be quoted in many different ways. Regardless of the method, however, the amount of the loan, the coupon, and the par value of the loan are the same. The only difference in the methods is how the interest rate is quoted. This multiplicity of ways of quoting interest rates is a cause of constant confusion for novices attempting to analyze money market instruments and has no value for experts. We propose a single way to quote money market interest rates regardless of the type of money market instrument. The proposed method is not only consistent for the various instruments; it is also consistent with the Truth in Lending Law.
Combinatorial QSAR Modeling of Specificity and Subtype Selectivity of Ligands Binding to Serotonin Receptors 5HT1E and 5HT1F

The Quantitative Structure-Activity Relationship (QSAR) approach has been applied to model binding affinity and receptor subtype selectivity of human 5HT1E and 5HT1F receptor-ligands. The experimental data were obtained from the PDSP Ki Database. Several descriptor types and data-mining approaches have been used in the context of combinatorial QSAR modeling. Data mining approaches included k Nearest Neighbor, Automated Lazy Learning (ALL), and PLS; descriptor types included MolConnZ, MOE, DRAGON, Frequent Subgraphs (FSG), and Molecular Hologram Fingerprints (MHFs). Highly predictive QSAR models were generated for all three data sets (i.e., for ligands of both receptor subtypes and for subtype selectivity), and different individual techniques were proved best in each case. For real value activity data available for 5HT1E and 5HT1F ligand binding, models were characterized by leave-one-out cross-validated R(2) (q(2)) for the training sets and predictive R(2) values for the test sets. The best models for 5HT1E ligands were obtained with the kNN approach combined with MolConnZ descriptors (q(2)=0.69, R(2)=0.92); for 5HT1F ligands ALL QSAR method using MolConnZ descriptors gave the best results (R(2)=0.92). Rigorously validated classification models were also developed for the 5HT1E/5HT1F subtype selectivity data set with high correct classification accuracy for both training (CCRtrain=0.88) and test (CCRtest=1.00) sets using kNN with MolConnZ descriptors. The external predictive power of QSAR models was further validated by virtual screening of The Scripps Research Institute (TSRI) screening library to recover 5HT1E agonists and antagonists (not present in the original PDSP data set) with high enrichment factors. The successful development of externally predictive and interpretative QSAR models affords further design and discovery of novel subtype specific GPCR agents.
An Operator-Fractal

Certain Bernoulli convolution measures μ are known to be spectral. Recently, much work has concentrated on determining conditions under which orthonormal Fourier bases (i.e. spectral bases) exist. For a fixed measure known to be spectral, the ONB need not be unique; indeed, there are often families of such spectral bases. Let for a natural number n and consider the Bernoulli measure with scale factor λ. It is known that L 2(μλ) has a Fourier basis. We first show that there are Cuntz operators acting on this Hilbert space which create an orthogonal decomposition, thereby offering powerful algorithms for computations for Fourier expansions. When L 2(μλ) has more than one Fourier basis, there are natural unitary operators U, indexed by a subset of odd scaling factors p; each U is defined by mapping one ONB to another. We show that the unitary operator U can also be orthogonally decomposed according to the Cuntz relations. Moreover, this operator-fractal U exhibits its own self-similarity.
Fast Configurable-Cache Tuning With a Unified Second-Level Cache

Tuning a configurable cache subsystem to an application can greatly reduce memory hierarchy energy consumption. Previous tuning methods use a level one configurable cache only, or a second level with separate instruction and data configurable caches. We instead use a commercially-common unified second level cache, a seemingly minor difference that actually expands the configuration space from 500 to about 20 000. We develop additive way tuning for tuning a cache subsystem with this large space, yielding 61% energy savings and 9% performance improvements over a nonconfigurable cache, greatly outperforming an extension of a previous method.
Exact learning of DNF formulas using DNF hypotheses

We show the following: (a) For any @e>0, log^(^3^+^@e^)n-term DNF cannot be polynomial-query learned with membership and strongly proper equivalence queries. (b) For sufficiently large t, t-term DNF formulas cannot be polynomial-query learned with membership and equivalence queries that use t^1^+^@e-term DNF formulas as hypotheses, for some @e<1 (c) Read-thrice DNF formulas are not polynomial-query learnable with membership and proper equivalence queries. (d) logn-term DNF formulas can be polynomial-query learned with membership and proper equivalence queries. (This complements a result of Bshouty, Goldman, Hancock, and Matar that logn-term DNF can be so learned in polynomial time.) Versions of (a)-(c) were known previously, but the previous versions applied to polynomial-time learning and used complexity theoretic assumptions. In contrast, (a)-(c) apply to polynomial-query learning, imply the results for polynomial-time learning, and do not use any complexity-theoretic assumptions.
New examples of obstructions to non-negative sectional curvatures in cohomogeneity one manifolds

K. Grove, L. Verdiani, B. Wilking and W. Ziller gave the first examples of cohomogeneity one manifolds which do not carry invariant metrics with non-negative sectional curvatures. In this paper we generalize their results to a larger family. We also classified all class one representations for a pair (G;H) with G/H some sphere, which are used to construct the examples.
Diesel Electric Locomotive Propulsion Systems-A Look into the Future

The demand for increased productivity in train operation has been the driving force in creating today's energy-efficient high-horsepower diesel electric locomotives. A key in obtaining this productivity improvement has been the evolution of the electric transmission that has allowed the locomotive's effective tractive effort to increase along with its diesel engine horsepower. A means of correlating the relative efficiency, reliability, performance, size, and weight of the available propulsion technologies and control strategies is developed, along with trade-offs in applying these technologies and strategies to locomotives now and in the future. Both dc and the various types of ac propulsion technologies are included. How the basic strategy of individual axle control or total locomotive control (for both dc and ac technologies) relates to locomotive productivity is covered along with variations such as power equipment staging in the overall optimization process.
Yield Curve Risk in Japanese Government Bond Markets

This paper characterizes the nature of yield curve risk in the Japanese government bond (JGB) market, and explores the effectiveness of risk management based on a linear factor representation of yield curve risk. The implied optimal hedges against factor risk are related to duration-based hedging strategies, which are shown in many cases to be substantially sub-optimal. In addition, the drift over time in optimal hedge ratios due to the local nature of optimal hedging is investigated. The results show substantial drift especially for the weights on the factor representing the risk of a changing slope of the JGB yield curve. Though our focus is on government bond markets, the findings have implications for risk management for most interest-sensitive instruments, especially those that are priced relative to government bonds (e.g. corporate bonds).
Trimethylaluminum-Promoted Cyclization of Cyanoenaminones. A Versatile Synthesis of Substituted Pyrazolopyridines

Abstract Trimethylaluminum (TMA) promotes the cyclization of cyanoenaminones to form [b]-fused pyrazolopyridine derivatives.
M2Ba2Sn6 (m =yb, ca): metallic zintl phases with a novel tin chain substructure.

The compounds M2Ba2Sn6 (M = Yb, Ca) have been synthesized by solid-state reactions in welded Ta tubes at high temperature. Their structures were determined by single-crystal X-ray diffraction studies to be orthorhombic; space group Cmca (No. 64); Z = 8; a = 15.871(3), 15.912 (3) A; b = 9.387(2), 9.497(2) A; c = 17.212(3), 17.184(3) A; and V = 2564.3(9), 2597.0(9) A3, respectively. These contain infinite tin chains along a constructed from butterflylike 3-bonded Sn tetramers interconnected by pairs of 2-bonded Sn. The chains are further interconnected into corrugated layers by somewhat longer Sn−Sn bonds along c. The compounds with the chains alone would be Zintl phases, but the interchain bonding makes them formally one-electron rich per formula unit. The electronic structures calculated by extended Huckel and TB-LMTO-ASA methods indicate that these compounds are metallic but with a deep pseudogap at the Fermi level. States that bind the extra electrons lie just below EF and involve important Yb(Ca)−Sn ...
A new paradigm for 3D collisionless magnetic reconnection

A new paradigm is suggested for 3D magnetic reconnection where the interaction of reconnection processes with current aligned instabilities plays an important role. According to the new paradigm, the initial equilibrium is rendered unstable by current aligned instabilities (lower-hybrid drift instability first, drift-kink instability later) and the non-uniform development of kinking modes leads to a compression of magnetic field lines in certain locations and a rarefaction in others. The areas where the flow is compressional are subjected to a driven reconnection process. In the present paper we illustrate this series of events with a selection of simulation results.
Substituted Alkyne Synthesis under Nonbasic Conditions: Copper Carboxylate-Mediated, Palladium-Catalyzed Thioalkyne−Boronic Acid Cross-Coupling

A new methodology for the synthesis of substituted alkynes is described. In the presence of copper(I) thiophene-2-carboxylate (CuTC) or copper (I) 3-methylsalicylate (CuMeSal), the palladium-catalyzed cross-coupling of thioalkyne derivatives with boronic acids affords functionalized alkynes in yields ranging from 39 to 91%. This coupling occurs efficiently under mild, nonbasic conditions with a wide variety of thioalkynes and boronic acids, providing a reaction complementary to the Sonogashira protocol.
The Orbital Period of V368 Aquilae (Nova Aquilae 1936 No. 2)

We report observations of the eclipsing classical nova V368 Aql (Nova Aql 1936 No. 2). These data reveal that the orbital period previously published by Diaz & Bruch is an alias of the true orbital period. A total of 14 eclipses (12 complete and two partial) over 25 nights of observation have established that the orbital period of V368 Aql is 0.6905093(1) day (16.57 hr), which is roughly twice the previously published period. With its revised orbital period, V368 Aql now joins other nova systems with periods in excess of 0.5 day that dominate the long end of the orbital period distribution of cataclysmic variables.
Polymer Mixtures in Na2O.Sb2O3.GeO2 Glasses

Ternary Na2O.Sb2O3.GeO2 glasses (with various [Na]/[Na + Sb] ratios) that contained ≥65 mol% GeO2 were prepared. Their densities (volumes), refractive indices, and infrared spectra were determined and their colors noted. The ternary glasses with ≥88 mol% GeO2 exhibit nearly additive volumes, refractivities, and frequencies for the main Ge-O vibration. Ternary glasses with lesser amounts of GeO2 exhibit a variety of behaviors, depending on the [Na]/[Na + Sb] ratio. Small amounts of Sb2O3 cause significant volume and refraction deviations, as well as changes in νGe-O, that can be associated with gradual elimination of GeO6 octahedra. All the information supports a model for the glasses with 65 to 88 mol% GeO2 that involves a degree of depolymerization that is greater when Na2O and Sb2O3 are present together than when either is present alone.
Constructions and noise threshold of topological subsystem codes

Topological subsystem codes proposed recently by Bombin are quantum error-correcting codes defined on a two-dimensional grid of qubits that permit reliable quantum information storage with a constant error threshold. These codes require only the measurement of two-qubit nearest-neighbor operators for error correction. In this paper, we demonstrate that topological subsystem codes (TSCs) can be viewed as generalizations of Kitaev's honeycomb model to 3-valent hypergraphs. This new connection provides a systematic way of constructing TSCs and analyzing their properties. We also derive a necessary and sufficient condition under which a syndrome measurement in a subsystem code can be reduced to measurements of the gauge group generators. Furthermore, we propose and implement some candidate decoding algorithms for one particular TSC assuming perfect error correction. Our Monte Carlo simulations indicate that this code, which we call the five-square code, has a threshold against depolarizing noise of at least 2%.
Inconsistency of the MLE for the Joint Distribution of Interval‐Censored Survival Times and Continuous Marks

This paper considers the non-parametric maximum likelihood estimator (MLE) for the joint distribution function of an interval-censored survival time and a continuous mark variable. We provide a new explicit formula for the MLE in this problem. We use this formula and the mark-specific cumulative hazard function of Huang & Louis (1998) to obtain the almost sure limit of the MLE. This result leads to necessary and sufficient conditions for consistency of the MLE, which imply that the MLE is inconsistent in general. We show that the inconsistency can be repaired by discretizing the marks. Our theoretical results are supported by simulations.
The need for structural allograft biomechanical guidelines

Because of their osteoconductive properties, structural bone allografts retain a theoretic advantage in biologic performance compared with artificial interbody fusion devices and endoprostheses. Present regulations have addressed the risks of disease transmission and tissue contamination, but comparatively few guidelines exist regarding donor eligibility and bone processing issues with a potential effect on the mechanical integrity of structural allograft bone. The lack of guidelines appears to have led to variation among allograft providers in terms of processing and donor screening regarding issues with recognized mechanical effects. Given the relative lack of data on which to base reasonable screening standards, we undertook basic biomechanical evaluation of one source of structural bone allograft, the femoral ring. Of our tested parameters, the minimum and maximum cortical wall thicknesses of femoral ring allograft were most strongly correlated with the axial compressive load to failure of the graft, suggesting that cortical wall thickness may be a useful screening tool for compressive resistance expected from fresh cortical bone allograft. Development of further biomechanical and clinical data to direct standard development appears warranted.
Price volatility and futures margins

Futures exchanges raise margins in environments characterized by recent substantial increases in futures price volatility, and they raise margins in contracts that have recently shown the largest volatility increase. Volatility then tends to fall. This reduction is smaller - especially the troublesome jump component of volatility that is derived from a Poisson jump-diffusion process of futures daily returns - when the earlier margin increase is larger. The exchanges appear to raise margins when they perceive the earlier volatility increase to be more permanent. Conversely, exchanges reduce margins after an earlier decrease in volatility, but they seem anxious to reduce margins well before volatility has bottomed out. After the margin reduction, volatility continues to decline and by a greater amount for the cases when the earlier reduction in margins was larger.
High quality factor and high confinement silicon resonators using etchless process

We demonstrate high-Q factor and high confinement silicon ring resonators fabricated by a local oxidation of silicon (LOCOS) process. We achieve an intrinsic quality factor of 525,000 in 410 μm-circumference ring resonator.
Positivity and complexity of ideal sheaves

The problem of bounding the “complexity" of a polynomial ideal in terms of the degrees of its generators has attracted a great deal of interest in recent years. Results in this direction go back at least as far as the classical work [17] of Hermann on the ideal membership problem, and the effective Nullstellensatz of Brownawell [4] and Kollar [21] marks a major recent advance.With the development of computational algebraic geometry the question has taken on increasing importance, and it came into particularly clear focus through the influential paper [3] of Bayer andMumford.More recently, the theorem of [8] and [20] concerning regularity of powers raises the question of bounding the complexity of powers of an ideal, and suggests that asymptotically the picture should become very clean. The aim of the present paper is to examine some of the results and questions of [3], [30] and [7] from a geometric perspective, in the spirit of [12]. Our thesis is that much of this material is clarified, and parts rendered transparent, when viewed through the lenses of vanishing theorems and intersection theory. Specifically,motivated by thework [25], [26] of Paolettiwe introduce an invariant s(J ) thatmeasures in effect howmuchonehas to twist an idealJ in order tomake
A practical synthesis of the lipophilic side chain of the polyoxypeptins

Abstract The lipophilic side chain of the cyclic depsipeptide polyoxypeptin A ( 1 ) and B ( 2 ), strong apoptosis inducers, has been synthesised as an ester of mixed methyl ketal 18 . The key step is an asymmetric anti -aldol reaction of the designed 2-( N -2-methylbenzyl- N -2,4,6-trimethylbenzyl) amino-1-phenylpropyl ester 8 by means of a combination of LDA–Cp 2 ZrCl 2 (0.3 equiv.) for enolation and transmetallation into the zirconium enolate for aldolization. By using a non-boron associated anti -aldol reaction, 10 g of the key lactone 6 were synthesised in six steps from 8 and in 48% overall yield.
Catalytic Asymmetric Synthesis of Branched Chiral Allylic Phenyl Ethers from (E)-Allylic Alcohols

The first di-μ-amidate dipalladium complexes and a new di-μ-carboxylate dipalladium complex of the COP (cobalt oxazoline palladacycle) palladium(II) catalyst family are reported and characterized crystallographically. The di-μ-amidate complex 3 or its enantiomer (ent-3) are the first asymmetric catalysts that allow commercially available, or readily accessible, (E)-2-alkene-1-ols to be transformed to enantioenriched branched allylic aryl ethers upon reaction of their trichloroacetimidate derivatives with phenols. The 3-aryloxy-1-alkene products are formed in high enantiomeric purity (typically 90–98% ee) and useful yields (61–88%).
Optimal strategies for computing symmetric Boolean functions in collocated networks

We address the problem of finding optimal strategies for computing Boolean symmetric functions. We consider a collocated network, where each node's transmissions can be heard by every other node. Each node has a Boolean measurement and we wish to compute a given Boolean function of these measurements with zero error. We allow for block computation to enhance data fusion efficiency, and determine the minimum worst-case total bits to be communicated to perform the desired computation. We restrict attention to the class of symmetric Boolean functions, which only depend on the number of 1s among the n measurements. We define three classes of functions, namely threshold functions, delta functions and interval functions. We provide exactly optimal strategies for the first two classes, and an order-optimal strategy with optimal preconstant for interval functions. Using these results, we can characterize the complexity of computing percentile type functions, which is of great interest. In our analysis, we use lower bounds from communication complexity theory, and provide an achievable scheme using information theoretic tools.
Organizational commitment among general practitioners: A cross-sectional study of the role of psychosocial factors

Objective. To examine whether general practitioners (GP) working in primary health care have lower organizational commitment compared with physicians working in other health sectors. The authors al...
Equilibrium and migration in dynamic models of housing markets

Abstract This paper presents a model of a regional housing market where households choose among competing employment opportunities offered by cities within a given system. The equilibrium requirement imposed in the model requires that households be indifferent among all locations both within their current city and other cities within the region, rather than in terms of exogenously determined utility or populations. This construction allows the characterization of equilibrium in terms of potentially observable variables related to household income. Given that equilibrium can be defined in this more general manner, it is natural to identify ways in which the predictions will differ from those generated by existing models. Capozza and Helsley's (J. Urban Econ. 28 (1990) 180–203) model of land conversion is evaluated in this context. In this setting, the option value associated with the ability to delay development depends directly on the degree to which the income processes are correlated across cities. Also, increased idiosyncratic income risk does not necessarily lead to larger option values.
Use of a Lithiolactone in the Enantioselective Constructions of A/C seco-B and of A/B seco-C proTaxol Systems

Abstract We show that an unusual lithiolactone system is a useful starting point for the construction of various intermediates to the taxol structure. © 1997 Elsevier Science Ltd.
The implementation of the Cm* multi-microprocessor

The implementation of a hierarchical, packet switched multiprocessor is presented. The lowest level of the structure, a Computer Module, is a processor-memory pair. Computer Modules are grouped to form a cluster; communication within the cluster is via a parallel bus controlled by a centralized address mapping processor. Clusters communicate via intercluster busses. A memory reference by a program may be routed, transparently, to any memory in the system. This paper discusses the hardware used to implement the communication mechanism. The use of special diagnostic hardware and performance models is also discussed.
Satellite power system LEO vs GEO assembly issues

A strawman crystal-silicon 5-GW satellite power system (SPS) concept formed the basis of a study of construction concepts for building a complete SPS in low Earth orbit (LEO) or geosynchronous orbit (GEO). Construction scenarios were evolved, including factory-in-space concepts and operations. Design implications imposed on the SPS satellite as a consequence of in-orbit assembly operations, and related attitude control requirements during assembly in LEO or GEO environments, were also evaluated. Results are presented indicating that complete assembly of an operational SPS in LEO, followed by transport to GEO, does not appear technically desirable. The best mix, however, of LEO vs GEO construction activity remains to be resolved.
Food Safety Program: Endrin Monitoring in the Mississippi River

Twelve successive monthly samplings and analyses of representative fish and shellfish and of mud and water from the lower Mississippi River showed neither a high concentration of endrin nor a time-ordered change in the concentration. The general absence of endrin from the samples indicated no significant contamination.
Effects of tissue inhibitor of metalloproteinase 2 deficiency on aneurysm formation

Objective Matrix metalloproteinase (MMP)-2 has been shown to play a pivotal role in aortic aneurysm formation. Its activation requires formation of a trimolecular complex of MMP-2, tissue inhibitor of metalloproteinase-2 (TIMP-2), and membrane type 1 (MT1)-MMP, which is attached to the cell surface. At higher concentrations, TIMP-2 becomes an inhibitor of MMP-2. Thus, TIMP-2 could both augment and inhibit matrix degradation. This study was undertaken to define the net effect of TIMP-2 on matrix destruction and aneurysm formation. Methods The abdominal aortas of wild-type and TIMP-2–deficient (TIMP-2 −/− ) mice were exposed to 0.25 mol/L CaCl 2 or 0.9% NaCl for 15 minutes after laparotomy. Aortic diameters were measured before treatment and 6 weeks after aneurysm induction. In addition, aortic tissues were studied for MMP-2 activation by zymography, and matrix structure was studied by connective tissue staining. Results The aortic diameter increased in both wild-type and TIMP-2 −/− mice. The increase in the TIMP-2 −/− mice was significantly smaller after CaCl 2 treatment (51% ± 3%) compared with the diameter of wild-type mice (67% ± 4%). Connective staining of aortic sections from the CaCl 2 -treated mice revealed disruption and fragmentation of the medial elastic lamellae in both wild-type and TIMP-2 −/− mice. Zymographic analysis showed that active MMP-2 levels were decreased in TIMP-2 −/− aortas compared with wild-type mice. Conclusions Targeted deletion of TIMP-2 results in attenuation of aneurysm development. Despite its name as an inhibitor of MMPs, TIMP-2 promotes aortic enlargement in vivo, presumably through its role as a cofactor in the activation of MMP-2.
Separation shock dynamics in Mach 5 turbulent interactions induced by cylinders

Wall pressure fluctuations have been measured under the unsteady separation shock in interactions generated by unswept circular cylinders. Models were tested in the turbulent boundary layers on the tunnel floor and on a full-span flat plate. The freestream unit Reynolds number was 53×10 6 m -1 , and the wall temperature approximately adiabatic. Distributions of the shock frequency, shock period, and shock speeds in the upstream and downstream directions have been calculated
Smaller building blocks form larger assemblies: Aggregation Behavior of biaryl-based dendritic facial amphiphiles

Synthesis and micellar behavior of biaryl-based benzyl ether dendritic molecules prepared from a new biaryl building block are described. The key objective of the study is to tune the size of individual dendritic molecules and investigate its effect on aggregation behavior of the resulting micelle-like assemblies. We show that the functional group placement in the building block influences flexibility of the dendritic backbone and interior volume available for packing the hydrophobic groups, which is reflected in different aggregation behavior and aggregate size of the two types of micellar assemblies.
Palladium-catalyzed, asymmetric Baeyer–Villiger oxidation of prochiral cyclobutanones with PHOX ligands

Described in this report is a general method for the conversion of prochiral 3-substituted cyclobutanones to enantioenriched γ-lactones through a palladium-catalyzed Baeyer–Villiger oxidation using phosphinooxazoline ligands in up to 99% yield and 81% ee. Lactones of enantiopurity ≥ 93% could be obtained through a single recrystallization step. Importantly, 3,3-disubtituted cyclobutanones produced enantioenriched lactones containing a β-quaternary center.
The Dynamic Demand for Capital and Labor

A model of the dynamically interrelated demand for capital and labor is specified and estimated. The estimates are of the first-order conditions of the firm's problem rather than of the closed-form decision rules. This use of the first-order conditions allows a random rate of return and a flexible specification of the technology. The estimates do not imply the very slow rates of adjustment displayed in other, related estimates of the demand for capital. Because adjustment is estimated to be rapid, there is, contrary to the standard view, scope for factor prices to affect investment at relatively high frequencies.