cssi/SciSciGPT-SciSciNet huggingface dataset:
Sharp trace inequalities for fractional Laplacians

The sharp trace inequality of Jose Escobar is extended to traces for the fractional Laplacian on R^n and a complete characterization of cases of equality is discussed. The proof proceeds via Fourier transform and uses Lieb's sharp form of the Hardy-Littlewood-Sobolev inequality.
To Trade or Not to Trade: The Effect of Broker Search and Discretionary Trading on Securities Market Performance

In this article we examine the interaction of brokerage search with the Bayesian learning behavior of competitive dealers under asymmetric information. We particularly focus on the effects of price search and discretionary trading on the performance of a dealer market. A search process is incorporated into a model in which brokers determine their reservation price and whether to continue their trades. The model enables us to uncover the interrelationships among search cost, bid-ask spread, and price volatility. We show that both spread revision and price volatility are dependent upon the optimal search process, inventory fluctuation, and search cost. Furthermore, our model predicts a negative relationship between price volatility and liquidity trading volume.
Type IIB orientifolds, F-theory, Type I strings on orbifolds and Type I-heterotic duality

Abstract We consider six- and four-dimensional N = 1 supersymmetric orientifolds of Type IIB compactified on orbifolds. We give the conditions under which the perturbative world-sheet orientifold approach is adequate, and list the four-dimensional N = 1 orientifolds (which are rather constrained) that satisfy these conditions. We argue that in most cases orientifolds contain nonperturbative sectors that are missing in the world-sheet approach. These non-perturbative sectors can be thought of as arising from D-branes wrapping various collapsed 2-cycles in the orbifold. Using these observations, we explain certain “puzzles” in the literature on four-dimensional orientifolds. In particular, in some four-dimensional orientifolds the “naive” tadpole cancellation conditions have no solution. However, these tadpole cancellation conditions are derived using the world-sheet approach which we argue to be inadequate in these cases due to appearance of additional non-perturbative sectors. The main tools in our analyses are the map between F-theory and orientifold vacua and Type I-heterotic duality. Utilizing the consistency conditions we have found in this paper, we discuss consistent four-dimensional chiral N = 1 Type I vacua which are non-perturbative from the heterotic viewpoint.
Applications of inverse chromatography in organic geochemistry—I. Characterization of polar solute-soil organic matter interactions by high performance liquid chromatography

Abstract In order to more fully understand the role of soil and sedimentary organic matter (SOM) in the migration and fate of organic pollutants in aquatic systems, a fast and accurate liquid chromatography method has been developed for the determination of sorption isotherms. The method is a modified Frontal Analysis by Characteristic Point (FACP) technique which accounts for hydrodynamic dispersion and which uses conventional HPLC equipment coupled with commercially available chromatography software. We have used this technique to generate sorption isotherms for various fractions of the total SOM. Isotherms are then fit to the Freundlich equation, from which water-organic carbon distribution coefficients ( K oc values) can be calculated. In this presentation we report on our studies of the roles played by various fractions of soil organic matter (lipids, humic/fulvic acids and humin) in the overall sorption process. By using solute probes which interact with solid phases in well-defined ways, we have been able to determine the contributions of acidic, basic and dipolar sites in the various SOM fractions as well as the contribution of nonspecific hydrophobic partitioning, in the sorption of nonionic, polar organic solutes. It appears that these solutes interact with soil organic matter primarily through specific interactions with active sites in the humin fraction of the organic matrix, although there is some hydrophobic partitioning into the lipid fraction as well.
Novel binning method for improved accuracy and speed of volume image coregistration using normalized mutual information

There is a growing consensus that mutual voxel information based measures hold great promise for fully automated multimodal image registration. We have found that image greyscale binning using a specific variation of contrast- limited histogram equalization (which we call histogram preservation) provides significant reduction of noise and spurious local maxima in the normalized mutual information function without causing significant displacement or smoothing of the global maximum. These effects are also relatively robust in the presence of image subsampling, so that accurate subpixel coregistration of typical medical volume images may be achieved in a few seconds by a very simple optima search algorithm based on a few thousand sampled voxels. In this paper, we illustrate these effects by presenting the results of random tests on patient data. Intramodal performance is evaluated by image self- registration using a variety of patient image volumes. Reregistration error is measured as the mean of the residual Euclidean displacement of the eight corner points of the image volumes after reregistration. The performance of histogram preservation prebinning is compared to linear prebinning, and the effect of image subsampling and number of bins on algorithm speed and accuracy is also assessed.
A Tverberg-type result on multicolored simplices

Abstract Let P1, P2,…, Pd+1 be pairwise disjoint n-element point sets in general position in d-space. It is shown that there exist a point O and suitable subsets Qi ⊆ Pi (i = 1, 2,…, d + 1) such that Qi ≥ cdPi, an every d-dimensional simplex with exactly one vertex in each Qi contains Q in its interior. Here cd is a positive constant depending only on d.
Feature-based assembly mating reasoning

This paper presents a feature-based method to obtain assembly mating relations between a set of polyhedral components. Previous research in assembly planning has assumed that these assembly mating relations, or equivalent information such as the final assembled configuration of the components, is provided as part of the problem input. This paper addresses the case where only the component geometry is provided, which can arise in product maintenance or emergency repair applications where the originally designed assembly mating relations are no longer valid, and in robotic autonomous construction applications. The basis of the method is to represent components in terms of form features using a feature recognition method based on Alternating Sum of Volumes with Partitioning (ASVP) decomposition. Feature recognition is applied to each component to obtain its Form Feature Decomposition (FFD), which is a hierarchy of positive and/or negative form features. Positive form features of each component are compared with negative form features of other components to obtain mating relations between pairs of features. Multiple feature matings between the same pair of components are merged into component matings, which comprise the assembly mating relations. A backtracking search generates all feasible assembly configurations from the component matings.
Robotic pediatric urology.

Robotic-assisted minimally invasive surgery is penetrating pediatric urology. The freedom afforded by the “surgical actuators” has led to the expanding adoption of robotics, and it is unlikely that much of laparoscopy will not trend toward some iteration of robotic influence. The da Vinci surgical system (Intuitive Surgical, Sunnyvale, CA) provides delicate telemanipulation, coalesced with three-dimensional visualization and superior magnification. It has bridged the gap between laparoscopy and open surgery. Nonetheless, a confident understanding of pure laparoscopy is paramount in the event that mechanical malfunction is experienced. Robotic pediatric urologic procedures such as pyeloplasty, ureteral reimplantation, abdominal testis surgery, and partial or total nephrectomy with or without ureteral stump removal are routinely performed at select centers offering robotic expertise. Complex reconstructive surgeries such as appendicovesicostomy, antegrade continent enema creation, and augmentation cystoplasty can be performed but are still in their infancy.
Ethyl lactate as a tunable solvent for the synthesis of aryl aldimines

Ethyl L-lactate can be tuned with a cosolvent to create polarity conditions ideal for synthesizing aryl aldimines that crystallize directly out of solution within minutes under ambient conditions in excellent yields and requiring no further purification.
ASSOCIATIVITY RELATIONS IN QUANTUM COHOMOLOGY

The geometry of moduli spaces of stable maps of genus 0 curves into a complex projective manifold X leads to a system of quadratic equations in the tree-level (genus 0) Gromov-Witten numbers of X. In elementary examples, these equations solve for all such numbers, uniquely and consistently, from starting data. The beautiful paper of Di Francesco and Itzykson [1] presents a number of examples in this context. One of the foundational papers in the area of quantum cohomology, [4], explains this phenomenon, at least in some cases, by proving the first reconstruction theorem. This theorem applies to manifoldsX such thatH∗(X,Q) is generated byH(X). This result gives an effective procedure for solving for genus 0 Gromov-Witten numbers from starting data using the quadratic relations (since this entire paper is concerned only with the genus 0 invariants, we omit explicit mention of genus from now on). In all but the simplest cases there will be more than one way of using the relations to solve for the numbers. In other words, the system of equations is overdetermined. In the same paper the authors ask whether the seemingly redundant equations follow algebraically from the useful ones. Consistency of this overdetermined system of equations, as an algebraic (or combinatorial) statement rather than a geometric statement, has only been noted in the literature in isolated instances, cf. [2]. The equations were predicted on the basis of physical theories and later confirmed by rigorous study of the moduli spaces. The view taken by the physicists is quite useful: the numbers are combined into a generating function and the relations are represented by differential equations. The survey paper [6] documents these early studies. This paper continues in the spirit of these early investigations into the structure of the relations. The main result is a generalization of the first reconstruction theorem. Keeping the hypothesis that the cohomology ring of X is generated by divisors, we show that an initial collection of numbers and relations determines, purely algebraically, the entire system of relations (strong reconstruction) as well as the Gromov-Witten numbers. Examples, in the last section, illustrate the existence of non-geometric solutions. For a manifold X with H = H∗(X,C), the associativity relations can be expressed geometrically by saying that an associated connection on TH is flat, i.e., that the quantum potential function dictates on H the structure of a Frobenius manifold [2, 4]. Near a semisimple solution, the equations for flatness can be proved equivalent (with suitable assumptions) to the well-studied Schlesinger equations, cf. [5]. Strong
Dynamically generated electric charge distributions in Abelian projected SU(2) lattice gauge theories.

Abstract We show in the maximal Abelian gauge the dynamical electric charge density generated by the coset fields, gauge fixing and ghosts shows antiscreening as in the case of the non-Abelian charge. We verify that with the completion of the ghost term all contributions to flux are accounted for in an exact lattice Ehrenfest relation.
Solar wind excitation of Pc5 fluctuations in the magnetosphere and on the ground

[1] The primary purpose of this paper is to show the importance of solar wind excitation as a source of magnetospheric and ground Pc5 fluctuations. In particular, we show that pressure fluctuations, a nearly ubiquitous feature of the solar wind, drive magnetospheric compressional Pc5, whose amplitude and power increase in direct proportion to the amplitude and power of the solar wind pressure fluctuations. Previous studies of compressional Pc5 have focused primarily on internally generated waves on the dusk flank; here we highlight the pressure fluctuations associated with geoeffective high-speed streams (HSSs) and interplanetary coronal mass ejections (ICMEs) during a time interval in March and April 2002, in the declining phase of the solar cycle, when there was a favorable alignment of satellites. Using three examples and a statistical survey, we show that for this time interval external forcing due to solar wind dynamic pressure fluctuations was dominant over internal forcing. Fluctuations driven by internal processes, occurring primarily at dusk and on the nightside, accounted for less than 20% of the total power. We also found that multiple external forcing processes were occurring during this interval, including evanescent propagation of compressional waves, field line resonance (FLR), and global mode excitation. We need to enlarge our vision of the source of ULF waves to include excitation by solar wind pressure fluctuations as a significant factor.
The 10 February 1977 lunar occultation of Uranus. Radius, limb darkening, and polar brightening at 6900 A

Contact timings, corrected for lunar limb effects, indicate an equatorial radius of 25700 + or - 500 km for the visible disk for Uranus. A modified Minnaert function is used to model limb darkening and polar brightening. Least squares fits to the observed light curve indicate that Uranus is slightly limb darkened in the passband of the observations (450 A FWHM centered near 6900 A) and that polar brightening is present.
Lattice QCD and heavy quarks

Abstract Some interesting heavy-flavor questions are mentioned that may yield to the methods of lattice QCD. Special emphasis is placed on topics which arise in the discussion of CP violation in B decays. Other subjects include quarkonium and light-quark systems and some potential applications outside QCD.
The Prairie Meteorite Network

A network of sixteen stations has been established in the Midwest to obtain photographic data on bright meteors. Special photo-electric techniques have been devised to automate the camera stations, which continuously patrol the nighttime sky.
CO2 splitting by H2O to CO and O2 under UV light in TiMCM-41 silicate sieve

The 266 nm light-induced reaction of CO{sub 2} and H{sub 2}O gas mixtures (including isotopic modifications {sup 13}CO{sub 2}, C{sup 18}O{sub 2}, and D{sub 2}O) in framework TiMCM-41 silicate sieve was monitored by in-situ FT-IR spectroscopy at room temperature. Carbon monoxide gas was observed as the sole product by infrared, and the growth was found to depend linearly on the photolysis laser power. H{sub 2}O was confirmed as stoichiometric electron donor. The work establishes CO as the single photon, 2-electron transfer product of CO{sub 2} photoreduction by H{sub 2}O at framework Ti centers for the first time. O{sub 2} was detected as co-product by mass spectrometric analysis of the photolysis gas mixture. These results are explained by single UV photon-induced splitting of CO{sub 2} by H{sub 2}O to CO and surface OH radical.
State-space model identification with data correlation

Abstract It is proved that a certain sample auto- and cross-correlation Hankel matrix can be used to develop an effective state-space model identification procedure. By incorporating data correlation with a state-space model identification method, identification bias, which is inherent in using the singular value decomposition of a noise-corrupted Hankel data matrix, can be significantly reduced. The proposed new identification procedure is different from other state-space identification methods which use correlation or covariance matrices, since the input excitation signals are not limited to a white gaussian noise or to an impulse. These inputs can be any time functions provided the persistent excitation condition is satisfied Communicated by Dr D. A. Wilson.
The role of lymph node metastasis in the systemic dissemination of breast cancer.

Background. Lymphatic invasion is necessary for regional lymph node (RLN) metastasis in breast cancer (BC), while systemic metastasis requires blood vessel (BV) invasion. The site of BV invasion could be at the primary BC site or through lymphovascular anastomoses. The vague pathologic term “lymphovascular invasion” (LVI) encourages the belief that peri/intratumoral BV invasion may be common. We investigated the relative contribution of RLN metastasis to systemic metastasis by studying the relationship among LVI and RLN and/or systemic metastasis in a population-based cohort of breast cancer patients.
Future of B physics at CDF and DØ

In this contribution to the panel discussion on ''The Future of Hadron B Experiments'' held at the 8th International Conference on B Physics at Hadron Machines (Beauty 2002) at Santiago de Compostela, Spain, June 17-21, 2002, we explore the physics potential for B physics at CDF and D0 in five years and beyond. After a brief introduction to precision flavour physics, we concentrate our discussion on the future of CP violation by evaluating the prospects for measuring the CKM angles {beta}, {gamma} and {alpha} at the Tevatron Collider experiments CDF and D0 by the end of Run II.
Opportunities and challenges in synthetic oligosaccharide and glycoconjugate research

Synthetic oligosaccharides and glycoconjugates are increasingly used as probes for biological research and as lead compounds for drug and vaccine discovery. These endeavors are, however, complicated by a lack of general methods for the routine preparation of this important class of compounds. Recent development such as one-pot multi-step protecting group manipulations, the use of unified monosaccharide building blocks, the introduction of stereoselective glycosylation protocols, and convergent strategies for oligosaccharide assembly, are beginning to address these problems. Furthermore, oligosaccharide synthesis can be facilitated by chemo-enzymatic methods, which employ a range of glycosyl transferases to modify a synthetic oligosaccharide precursor. Glycosynthases, which are mutant glycosidases, that can readily form glycosidic linkages are addressing a lack of a wide range glycosyltransferases. The power of carbohydrate chemistry is highlighted by an ability to synthesize glycoproteins.
On the Stability of Group Formation: Managing the Conflict Within

This paper develops a positive analysis of stable group formation, highlighting the role of conflict management within groups. The analysis builds on a simple economic model that features a “winner-take-all” contest for control of some resource. When a group forms, members pool their efforts in that contest and, if successful, apply the resource to a joint production process. While reducing the severity of conflict over the contestable resource relative to the case of individual conflict, the formation of groups adds another layer of conflict, that is, one between the members of the winning group over the distribution of their joint product. The effectiveness of conflict management in enabling groups to resolve this second layer of conflict in more “peaceful” ways has some important implications for the equilibrium structure of groups as well as for the allocation of resources.
Zirconium-catalyzed asymmetric carboalumination (ZACA reaction) of 1,4-dienes

Abstract Variously substituted 1,4-dienes containing a terminal vinyl (H2C CH) group, readily undergo the ZACA reaction with Me3Al and higher alkylalanes in a 1:1 molar ratio in the presence of a catalytic amount (1–5 mol %) of bis[(1-neomenthyl)indenyl]zirconium dichloride in good yields and in good enantioselectivity (70–92% ee), thereby providing an efficient and convenient route to various alkene-containing chiral natural products. Only the reaction of the parent 1,4-pentadiene is accompanied by extensive racemization.
Explaining the Evidence on Inequality and Growth: Informality and Redistribution

This paper constructs a simple model that can account for both the negative relationship between growth and income inequality observed in the cross-country data and the positive relationship observed within countries over time. The model employs a dual-economy structure with formal and informal sectors. Growth is driven by formal sector human capital spillovers. Restrictive institutions impose barriers to formality that reduce the growth rate and increase inequality. Redistributive taxation lowers inequality but blunts the incentive to accumulate, lowering growth. Institutional structures vary more across than within countries. Consequently, variations in institutional barriers to formality may account for the negative relationship between growth and inequality found in the cross-country data. Variations in the intensity of redistribution may account for the positive relationship observed within countries over time.
Phonons of Metallic Vicinal Surfaces

We present an analysis of the vibrational dynamics of metal vicinal surfaces using the embedded atom method to describe the interaction potential and both a real space Green's function method and a slab method to calculate the phonons. We report two main general characteristics: a global shift of the surface vibrational density of states resulting from a softening of the force field. The latter is a direct result of the reduction of coordination for the different type of surface atoms; and an appearance of high frequency modes above the bulk band, resulting from a stiffening of the force field near the step atom. The latter is due to a rearrangement of the atomic positions during the relaxation of the surface atoms yielding a large shortening of the nearest neighbor distances near the step atoms.
EQUIVALENCE RESULTS FOR OPTIMAL PASS‐THROUGH, OPTIMAL INDEXING TO EXCHANGE RATES, AND OPTIMAL CHOICE OF CURRENCY FOR EXPORT PRICING

Firms sometimes write price lists or catalogs for their exports, so they set prices for a period of time and do not adjust prices during that interval in response to changes in their environment. The firm sets the price either in its own currency or the importer's currency. This paper draws a simple link between the choice of currency and the pricing decision of a firm that changes prices in response to all shocks. Specifically, if the latter firm's price has a lower variance in terms of its own currency than the importer's currency, then the firm with a price list will set the price in its own currency (and otherwise it will set price in the foreign currency). This relationship is established by consideration of the firm with a price list as a special case of a firm that indexes its export price to the exchange rate. (JEL: F4, F1)
Precedent-Free Fault Isolation in a Diesel Engine Exhaust Gas Recirculation System

In this paper, a recently introduced model-based method for precedent-free fault detection and isolation (FDI) is modified to deal with multiple input, multiple output (MIMO) systems and is applied to an automotive engine with exhaust gas recirculation (EGR) system. Using normal behavior data generated by a high fidelity engine simulation, the growing structure multiple model system (GSMMS) approach is used to construct dynamic models of normal behavior for the EGR system and its constituent subsystems. Using the GSMMS models as a foundation, anomalous behavior is detected whenever statistically significant departures of the most recent modeling residuals away from the modeling residuals displayed during normal behavior are observed. By reconnecting the anomaly detectors (ADs) to the constituent subsystems, EGR valve, cooler, and valve controller faults are isolated without the need for prior training using data corresponding to particular faulty system behaviors.
Acute knee trauma: how many plain film views are necessary for the initial examination?

Objective. To determine whether anteroposterior (AP) and lateral views of the knee are equivalent to four views in acute fracture detection. Design. Three musculoskeletal radiologists retrospectively interpreted the plain film knee examinations of each patient, establishing ground truth for the presence or absence of a fracture. Cases were presented to four masked senior radiology residents twice – once as a two-view study and again as a four-view study – with 4 weeks separating the two reading sessions to minimize recall bias. Sensitivity, specificity, and diagnostic performance were calculated. Patients. Ninety-two patients presenting to the emergency department with acute knee trauma were evaluated with at least a four-view plain film examination. Results and conclusions. Mean sensitivity for fracture detection using four views (85%) was significantly higher than that using two views (79%). Mean specificity and receiver operating characteristic curve areas were not significantly different using two or four views. Four views are more sensitive than AP and lateral views alone in detection of acute knee fracture.
Acute Idiopathic Corneal Endotheliitis

Seven patients presenting with acute corneal stromal edema without prior surgery, trauma, ocular disease or known exposure to noxious agents are reported. One patient had a severe iridocyclitis; two others subsequently developed herpetic keratouveitis. Four cases, however, were unassociated with other known ocular disease. All four of these patients exhibited keratic precipitates and displayed minimal or no flare and cells in the anterior chamber, although the latter was largely obscured by the corneal edema. In each of these four instances, the inflammation and corneal edema resolved following topical corticosteroid therapy. In two of the four cases, both children, antibody to Herpes simplex virus could not be identified. We suggest that, in patients without known prior corneal disease or trauma, acute diffuse corneal stroma edema may stem from severe iridocyclitis or a primary endotheliitis due either to herpetic infection, the recently described presumed autoimmune corneal endotheliopathy, or a condition which we herein designate acute idiopathic corneal endotheliitis.
a Correlation Estimate for Quantum Many-Body Systems at Positive Temperature

We present an inequality that gives a lower bound on the expectation value of certain two-body interaction potentials in a general state on Fock space in terms of the corresponding expectation value for thermal equilibrium states of non-interacting systems and the difference in the free energy. This bound can be viewed as a rigorous version of first-order perturbation theory for many-body systems at positive temperature. As an application, we give a proof of the first two terms in a high density (and high temperature) expansion of the free energy of jellium with Coulomb interactions, both in the fermionic and bosonic case. For bosons, our method works above the transition temperature (for the non-interacting gas) for Bose–Einstein condensation.
Flux vacua and branes of the minimal superstring

We analyze exactly the simplest minimal superstring theory, using its dual matrix model. Its target space is one dimensional (the Liouville direction), and the background fields include a linear dilaton, a possible tachyon condensate, and RR flux. The theory has both charged and neutral branes, and these exhibit new and surprising phenomena. The smooth moduli space of charged branes has different weakly coupled boundaries in which the branes have different RR charges. This new duality between branes of different charges shows that the semiclassical notion of localized charge is not precise in the quantum theory, and that the charges of these branes can fluctuate. Correspondingly, the RR flux in some parts of target space can also fluctuate—only the net flux at infinity is fixed. We substantiate our physical picture with a detailed semiclassical analysis of the exact answers. Along the way, we uncover new subtleties in super-Liouville theory.
Total synthesis and structural revision of vannusals A and B: synthesis of the originally assigned structure of vannusal B.

The total synthesis of the originally assigned structure of vannusal B (2) and its diastereomer (d-2) are described. Initial forays into these structures with model systems revealed the viability of a metathesis-based approach and a SmI2-mediated strategy for the key cyclization to forge the central region of the molecule, ring C. The former approach was abandoned in favor of the latter when more functionalized substrates failed to enter the cyclization process. The successful, devised convergent strategy based on the SmI2-mediated ring closure utilized vinyl iodide (−)-26 and aldehyde fragment (±)-86 as key building blocks, whose lithium-mediated coupling led to isomeric coupling products (+)-87 and (−)-88 (as shown in Scheme 17 in the article). Intermediate (−)-88 was converted, via (−)-89 and (−)-90/(+)-91, to vannusal B structure 2 (as shown in Scheme 18 in the article), whose spectroscopic data did not match those reported for the natural product. Similarly, intermediate (+)-25, obtained through coup...
Do corporate governance characteristics influence tax management

Abstract This paper investigates how corporate governance plays a role in long-run tax management and contributes to the existing literature in several ways. First, we add insight into the horizon problems related to executive and director compensation and show that incentive compensation provides long-term incentives to improve performance by establishing a link between higher pay-performance sensitivity and lower taxes. Second, this is one of the first papers, to our knowledge, to empirically examine the role of governance in corporate tax management from a long-term perspective in order to better understand the lasting effects of governance. We find that incentive compensation drives managers to make investments into longer-horizon pay outs such as tax management. Furthermore, we find that this investment into tax management benefits shareholders; better tax management is positively related to higher returns to shareholders. We also address the endogeneity issues of corporate governance and performance measures. Finally, our paper is unique in examining which type of tax management strategy (domestic or foreign) different firms focus on. Our results shed light into how governance can improve firm performance and increase shareholder value in the long run.
The Extended k -tree Algorithm

Consider the following problem: Given k=2q random lists of n-bit vectors, L 1,…,L k , each of length m, find x 1∈L 1,…,x k ∈L k such that x 1+⋅⋅⋅+x k =0, where + is the XOR operation. This problem has applications in a number of areas, including cryptanalysis, coding theory, finding shortest lattice vectors, and learning theory. The so-called k-tree algorithm, due to Wagner, solves this problem in $\tilde{O}(2^{q+n/(q+1)})$ expected time provided the length m of the lists is large enough, specifically if m≥2n/(q+1). In many applications, however, it is necessary to work with lists of smaller length, where the above algorithm breaks down. In this paper we generalize the algorithm to work for significantly smaller values of the list length m, all the way down to the threshold value for which a solution exists with reasonable probability. Our algorithm exhibits a tradeoff between the value of m and the running time. We also provide the first rigorous bounds on the failure probability of both our algorithm and that of Wagner. As a third contribution, we give an extension of this algorithm to the case where the vectors are not binary, but defined over an arbitrary finite field $\mathbb{F}_{r}$, and a solution to λ 1 x 1+⋅⋅⋅+λ k x k =0 with $\lambda_{i} \in \mathbb{F}_{r}^{*}$ and x i ∈L i is sought.
DETECTING INTRACLUSTER GAS MOTION IN GALAXY CLUSTERS: MOCK ASTRO-E2 OBSERVATIONS

We explore the detectability of bulk motions in the X-ray-emitting intracluster medium using a catalog of 1836 mock Astro-E2 observations of simulated clusters of galaxies. We generate high-resolution mock spectra for two observing strategies: a four-pointing mosaic and a single central pointing. Normalizing to 200 (400) photons in the iron Kα region for the mosaic (central) study, we fit Poisson realizations of each simulated spectrum to a velocity-broadened isothermal plasma emission model. We confirm that the velocity characteristics (mean and dispersion) returned by the spectral fittings are unbiased measures of the emission-weighted values within the observed region, with scatter ±55 km s-1. The maximum velocity difference between mosaic element pairs Δvmax has ~6% likelihood of being transonic (Δvmax ≥ 0.5cs), and the likelihood falls steeply, p ∝ (Δvmax/cs)-4, at high Mach number. The velocity-broadening parameter σv from the central pointing fit exceeds the thermal value in 49% of the cases, with again a σ tail at large dispersion. We present as case studies the clusters that yield the strongest signal for each observing strategy.
Whirl flutter analysis of a horizontal-axis wind turbine with a two-bladed teetering rotor

Whirl flutter and the effect of pitch-flap coupling on teetering motion of a wind turbine were investigated. The equations of motion are derived for an idealized five-degree-of-freedom mathematical model of a horizontal-axis wind turbine with a two-bladed teetering rotor. The model accounts for the out-of-plane bending motion of each blade, the teetering motion of the rotor, and both the pitching and yawing motions of the rotor support. Results show that the design is free from whirl flutter. Selected results are presented indicating the effect of variations in rotor support damping, rotor support stiffness, and pitch-flap coupling on pitching, yawing, teetering, and blade bending motions. Previously announced in STAR as N82-23707
On using unstable electrohydraulic valves for control

High bandwidth, high flow rate electrohydraulic valves typically have two or more stages. Most multi-stage valves are expensive, require meticulously clean fluid, and introduce higher order dynamics. On the other hand, single-stage spool valves are cheaper and more reliable. However, a majority of them are not suitable for high bandwidth, high flow rate applications due to limitations of the electromechanical/solenoid spool-stroking actuators. In this paper we investigate the feasibility of reducing this limitation by exploiting the transient flow forces in the valve so as to achieve spool dynamics that are intrinsically open-loop unstable. While conventional valves are designed to be open-loop stable, the unstable valve design has to be stabilized via closed-loop feedback. Simulation case studies are conducted to examine the potential dynamic and energetic advantages that an unstable valve may offer. These studies indicate that unstable valves provide faster response than the stable counterparts when stroking forces are limited. Moreover, unstable valves tend to require less positive power and energy to operate.
EXACT SOLUTION OF THE SIX-VERTEX MODEL WITH DOMAIN WALL BOUNDARY CONDITIONS: CRITICAL LINE BETWEEN DISORDERED AND ANTIFERROELECTRIC PHASES

In the present paper we obtain the large N asymptotics of the partition function ZN of the six-vertex model with domain wall boundary conditions on the critical line between the disordered and antiferroelectric phases. Using the weights a = 1 - x, b = 1 + x, c = 2, |x| < 1, we prove that, as N → ∞, ZN = CFN2N1/12(1 + O(N-1)), where F is given by an explicit expression in x and the x-dependency in C is determined. This result reproduces and improves the one given in the physics literature by Bogoliubov, Kitaev and Zvonarev [Boundary polarization in the six-vertex model, Phys. Rev. E65 (2002) 026126]. Furthermore, we prove that the free energy exhibits an infinite-order phase transition between the disordered and antiferroelectric phases. Our proofs are based on the large N asymptotics for the underlying orthogonal polynomials which involve a non-analytical weight function, the Deift–Zhou non-linear steepest descent method to the corresponding Riemann–Hilbert problem, and the Toda equation for the tau-function.
A Semivirtual Watershed Model by Neural Networks

A semi-virtual watershed model is presented in this study. This model places the design rainfall distribution on the input layer and the predicted runoff hydrograph on the output layer. The optimization scheme developed in this study can train the model to establish a set of weights under the guidance of the kinematic wave theory. The weights are time dependent variables by which rainfall signals can be converted to runoff distributions by weighting procedures only. With the consideration of time dependence, the computational efficiency of virtual watershed models is greatly enhanced by eliminating unnecessary visitations between layers. The weighting procedure used in the semi-virtual watershed model expands the Rational method from peak runoff predictions to complete hydrograph predictions under continuous and non-uniform rainfall events.
NGC 7789: AN OPEN CLUSTER CASE STUDY

We have obtained high-resolution spectra of 32 giants in the open cluster NGC 7789 using the Wisconsin–Indiana–Yale–NOAO Hydra spectrograph. We explore differences in atmospheric parameters and elemental abundances caused by the use of the linelist developed for the Gaia-ESO Survey (GES) compared to one based on Arcturus used in our previous work. [Fe/H] values decrease when using the GES linelist instead of the Arcturus-based linelist; these differences are probably driven by systematically lower (∼−0.1 dex) GES surface gravities. Using the GES linelist we determine abundances for 10 elements—Fe, Mg, Si, Ca, Ti, Na, Ni, Zr, Ba, and La. We find the cluster's average metallicity [Fe/H] = 0.03 ± 0.07 dex, in good agreement with literature values, and a lower [Mg/Fe] abundance than has been reported before for this cluster (0.11 ± 0.05 dex). We also find the neutron-capture element barium to be highly enhanced—[Ba/Fe] = +0.48 ± 0.08—and disparate from cluster measurements of neutron-capture elements La and Zr (−0.08 ± 0.05 and 0.08 ± 0.08, respectively). This is in accordance with recent discoveries of supersolar Ba enhancement in young clusters along with more modest enhancement of other neutron-capture elements formed in similar environments.
What do the statin trials tell us

The results of five large-scale, randomized, placebo-controlled trials, involving nearly 31,000 subjects, attest to the benefits of statins in the prevention of coronary events. Several key observations can be made on the basis of the evidence from these investigations. Of primary importance is the fact that statins reduce coronary event rates in patients with or without coronary heart disease. The percentage reduction in risk increases with each successive year of statin therapy. Moreover, the risk reduction is proportional to the reduction in low-density lipoprotein cholesterol. Subgroup analyses have demonstrated that the efficacy of statins extends to specific subgroups of patients, including women, people with diabetes, and older individuals. These agents also reduce the risk of stroke and transient ischemic attacks in patients with coronary disease. Both the randomized trials and widespread clinical experience have confirmed that statins are safe and do not increase the risk of cancer or mortality. Several markers of atherosclerotic risk are ameliorated by statins, although the clinical significance of this observation remains under investigation. The broad range of the therapeutic effects of statins yields safe, effective management of hypercholesterolemia in current practice while also providing a foundation for additional therapeutic refinements in the future.
Synthesis and structure-activity studies of side-chain derivatized arylhydantoins for investigation as androgen receptor radioligands

A series of arylhydantoin derivatives modeled after the antiandrogen RU 58841 was generated to identify potential candidates for development as androgen receptor (AR) radioligands. Side-chain modified derivatives of RU 58841, suitable for labeling with either carbon-11 or radiohalogens (fluorine-18, iodine-123), were synthesized and tested for their AR binding affinities. The N-(iodopropenyl) derivative 13 (Ki = 13 nM) is a potential candidate for development as a radioiodinated AR ligand.
Understanding TCP Vegas: a duality model

We view congestion control as a distributed primal--dual algorithm carried out by sources and links over a network to solve a global optimization problem. We describe a multilink multisource model of the TCP Vegas congestion control mechanism. The model provides a fundamental understanding of delay, fairness and loss properties of TCP Vegas. It implies that Vegas stabilizes around a weighted proportionally fair allocation of network capacity when there is sufficient buffering in the network. It clarifies the mechanism through which persistent congestion may arise and its consequences, and suggests how we might use REM active queue management to prevent it. We present simulation results that validate our conclusions.
Estimation of Space–Time Branching Process Models in Seismology Using an EM–Type Algorithm

Maximum likelihood estimation of branching point process models via numerical optimization procedures can be unstable and computationally intensive. We explore an alternative estimation method based on the expectation-maximization algorithm. The method involves viewing the estimation of such branching processes as analogous to incomplete data problems. Using an application from seismology, we show how the epidemic-type aftershock sequence (ETAS) model can, in fact, be estimated this way, and we propose a computationally efficient procedure to maximize the expected complete data log-likelihood function. Using a space–time ETAS model, we demonstrate that this method is extremely robust and accurate and use it to estimate declustered background seismicity rates of geologically distinct regions in Southern California. All regions show similar declustered background intensity estimates except for the one covering the southern section of the San Andreas fault system to the east of San Diego in which a substanti...
Wavelet-based pavement distress detection and evaluation

An automated pavement inspection system consists of image acquisition and distress image processing. The former is accomplished with imaging sensors, such as video cameras and photomultiplier tubes. The latter includes distress detection, isolation, classification, evaluation, segmentation, and compression. We focus on wavelet-based distress detection, isolation, and evaluation. After a pavement image is decomposed into different-frequency subbands by the wavelet transform, distresses are transformed into high-amplitude wavelet coefficients and noise is transformed into low-amplitude wavelet coefficients, both in the high-frequency subbands, referred to as details. Background is transformed into wavelet coefficients in a low-frequency subband, referred to as approximation. First, several statistical criteria are developed for distress detection and isolation, which include the high-amplitude wavelet coefficient percentage (HAWCP), the high-frequency energy percentage (HFEP), and the standard deviation (STD). These criteria are tested on hundreds of pavement images differing by type, severity, and extent of distress. Experimental results demonstrate that the proposed criteria are reliable for distress detection and isolation and that real-time distress detection and screening is currently feasible. A norm for pavement distress quantification, which is defined as the product of HAWCP and HFEP, is also proposed. Experimental results show that the norm is a useful index for pavement distress evaluation.
Laparoscopic tubal sterilization: long-term postoperative follow-up.

Abstract Patients with laparoscopic tubal sterilization were followed for a period of 18 months to three years. Clinical data as well as follow-up questionnaires indicate that the incidence of gynecologic disease is lower than that reported after conventional tubal ligation. The study also confirms the low incidence of regret reported after interval sterilization.
Doppler Modulation of X-Ray Lines in Cygnus X-3

We measured Doppler shifts of three bright spectral lines in the X-ray emission from Cygnus X-3 as recorded by the Chandra X-Ray Observatory. Doppler shifts of lines associated with Si XIV and S XVI exhibit orbital modulation. The magnitude and phasing of this modulation relative to the orbital ephemeris indicate the location of the source of this emission within the wind emanating from the compact object's companion. These observations enable us to make an indirect measurement of the separation of the two stars. Under certain assumptions our observation of a line associated with Fe XXV also limits the mass of the compact object MC ≤ 3.6 M☉.
Spitzer Constraints on the z = 6.56 Galaxy Lensed by Abell 370

We report on Spitzer IRAC observations of the spectroscopically confirmed z = 6.56 lensed Lyα emitting source HCM 6A that was found behind the cluster Abell 370. Detection of the source at 3.6 and 4.5 μm, corresponding to rest-frame optical emission, allows us to study the stellar population of this primeval galaxy. The broadband flux density at 4.5 μm is enhanced compared to the continuum at other wavelengths, likely due to the presence of strong Hα in emission. The derived Hα line flux corresponds to a star formation rate of 140 M☉ yr-1, more than an order of magnitude larger than estimates from the ultraviolet continuum and Lyα emission line. The dust extinction required to explain the discrepancy is AV ~ 1 mag. The inference of dust at such high redshifts is surprising and implies that the first epoch of star formation in this galaxy occurred at z ~ 20.
Enantioselective Synthesis of Spiro[cyclohexane-1,3'-indolin]-2'-ones Containing Multiple Stereocenters via Organocatalytic Michael/Aldol Cascade Reactions.

Abstract Organocatalytic reactions of 3-olefinic oxindoles and pentane-1,5-dial were investigated to provide access to substituted spirocyclohexane oxindoles via Michael/aldol cascade reactions. Of particular interest, we have examined the stereochemical outcome of electron withdrawing and electron-donating groups on the oxindole ring nitrogen. Interestingly, we have observed that the N-protecting group on the oxindole has critical effect on aldol ring closure leading to ultimate stereochemical outcome of the hydroxyl center. The overall process is quite efficient and afforded products with multiple stereocenters in high yields and excellent enantioselectivities (>99% ee).
Amplitude Distribution of Cosmic Ray Events in Extrinsic IR Detectors

A method of calculating the amplitude distribution of cosmic ray events in IR detectors utilizing known range-energy relationships for the various cosmic particles (mostly protons and helium nuclei) and published cosmic ray energy spectra is described. Good agreement is obtained between the calculated amplitude distribution and the spurious events observed in an extrinsic detector during a flight test.
Three-Step Model for High-Harmonic Generation in Many-Electron Systems

The three-step model (TSM) of high-harmonic generation (HHG) is generalized to atomic and molecular many-electron systems. Using many-body perturbation theory, corrections to the standard TSM due to exchange and electron-electron correlations are derived. It is shown that canonical Hartree-Fock orbitals represent the most appropriate set of one-electron states for calculating the HHG spectrum. To zeroth order in many-body perturbation theory, a HHG experiment allows direct access, in general, to a combination of occupied Hartree-Fock orbitals rather than to the highest occupied molecular orbital by itself.