cssi/SciSciGPT-SciSciNet huggingface dataset:
Reduced-Order Dynamic Aeroelastic Model Development and Integration with Nonlinear Simulation

Piloted and batch simulations of the aeroservoelastic response are essential tools in the development of advanced flight control systems. In these simulations the number of differential equations must be sufficiently large to yield the required accuracy, yet small enough to enable real-time evaluations of the aircraft flying qualities, The challenge of these conflicting demands is reinforced by nonlinearities in the quasi-steady equations of motion and by the complex characteristies of the oscillatory forces. Our solution to the problem is based on a unique formulation that eliminates the need for auxiliary state variables to represent the unsteady aerodynamics. We also address transformations from the mean flight path axes to a body axes coordinate system and describe how the structural dynamie equations of motion are integrated with the quasi-steady, nonlinear, six-degree-of-freedom plant model. The unified model, which accurately preserves the roots of the dynamic aeroelastic system, includes provisions for control surface inputs and atmospheric turbulence.
Focusing through random media in space and time: a transmission matrix approach

We exploit the evolution in time of the transmission matrix following pulse excitation of a random medium to focus radiation at a selected time delay t′ and position r. The temporal profile of a focused microwave pulse is the same as the incident Gaussian pulse. The contrast in space at time t′ of the focused wave is determined by the participation number of transmission eigenvalues M′ and the size N′ of the measured transmission matrix. The initial rise and subsequent decay of the contrast observed reflect the distribution of decay rates of the quasi-normal modes within the sample.
Ligand basicities from reactions with Nd[(CF3CO)2CH]3·THF

Abstract Proton NMR spectroscopy has been used to obtain the equilibrium constants for the reaction in CDCl3 solvent: where B represents neutral bases with oxygen or nitrogen donors. The ΔG of reaction is well correlated with the Gutmann donor number of the bases. For the oxygen bases, ΔG correlates with Drago's EB parameter but not the CB parameter; for the nitrogen bases, the reverse was obtained (i.e., correlation with the CB but not the EB).
Microwave-assisted synthesis of symmetric and asymmetric viologens

Abstract Viologens are generally synthesized by N-alkylating 4,4′-bipyridine with alkyl halides. Under conventional heating conditions, however, their synthesis suffers from long reaction times and, often, low yields. In this work, symmetric and asymmetric viologens were synthesized under the assistance of microwave irradiation in good to excellent yields and in short reaction times.
Ferroelectric Thin Films for Microelectromechanical Device Applications

Ferroelectric thin films of the lead zirconate titanate family have been integrated with silicon-based micromachined structures in the fabrication of microelectromechanical devices. Sol-gel deposition techniques have been applied in the formation of ferroelectric thin films with high piezoelectric and pyroelectric coefficients for physical forces sensors and infrared detectors, respectively. Knowledge of both electrical and mechanical properties is important in realizing microelectromechanical devices with predictable performance. This pape reports piezoelectric coefficient, pyroelectric coefficient, dielectric constant, and Young’s modulus for lead zirconate titanate and lead titanate thin films.
Content Contribution for Revenue Sharing and Reputation in Social Media: A Dynamic Structural Model

This study examines the incentives for content contribution in social media. We propose that exposure and reputation are the major incentives for contributors. Besides, as more and more social media Web sites offer advertising-revenue sharing with some of their contributors, shared revenue provides an extra incentive for contributors who have joined revenue-sharing programs. We develop a dynamic structural model to identify a contributor's underlying utility function from observed contribution behavior. We recognize the dynamic nature of the content-contribution decision-that contributors are forward-looking, anticipating how their decisions affect future rewards. Using data collected from YouTube, we show that content contribution is driven by a contributor's desire for exposure, revenue sharing, and reputation and that the contributor makes decisions dynamically.
Multiple drug resistance.

Multiple drug resistance to antibacterial agents, antifungals, antivirals, antiprotozoals, and antitumor agents has risen spectacularly in the last decade or so and presently threatens eventually to put an end to successful chemotherapy in all of the above fields. This review summarizes the known origins of the problem, its present dimensions, the means employed to combat the phenomenon and promising avenues for future developments.
A best-first alignment algorithm for automatic extraction of transfer mappings from bilingual corpora

Translation systems that automatically extract transfer mappings (rules or examples) from bilingual corpora have been hampered by the difficulty of achieving accurate alignment and acquiring high quality mappings. We describe an algorithm that uses a best-first strategy and a small alignment grammar to significantly improve the quality of the transfer mappings extracted. For each mapping, frequencies are computed and sufficient context is retained to distinguish competing mappings during translation. Variants of the algorithm are run against a corpus containing 200K sentence pairs and evaluated based on the quality of resulting translations.
Switching Angular Velocity Observer for Rigid-Body Attitude Stabilization and Tracking Control

This paper provides a new switching angular velocity observer formulation to the classical problem of rigid-body attitude tracking control in the absence of angular rate measurements. Exponential convergence of the angular velocity state estimation errors is proven using a novel error signal definition through the use of this switching-type observer. The observer synthesis and convergence properties are independent of controller design. The switching ensures C0 continuity for all the estimated states. Further, the maximum number of switches required by the observer is shown to be finite and that zeno-type behavior cannot occur. A “separation-property” type result for the attitude tracking problem is established, wherein a proportional-derivative controller uses angular velocity estimates from the proposed switching observer in the absence of actual angular rate measurements, while ensuring almost global asymptotic stability for the overall closed-loop tracking error dynamics. The separation property is al...
A cross-exchange comparison of execution costs and information flow for NYSE-listed stocks

Abstract We examine execution costs for trades in NYSE issues completed on the NYSE, the NASD dealer market, and the regional stock exchanges during 1994. We find that effective bid-ask spreads are only slightly smaller at the NYSE. However, realized bid-ask spreads, which measure market-making revenue net of losses to betterinformed traders but gross of inventory or order-processing costs, are lower on the NYSE by a factor of two to three. This differential is attributable to the successful ‘cream skimming’ of uninformed trades by off-NYSE market makers. These findings reinforce existing concerns about whether orders are routed so as to receive the best possible execution.
The Knee: MR Imaging of Uniquely Pediatric Disorders

Skeleton immaturity and intense physical activity render the pediatric p opulation prone to musculoskeletal injury. Knee pain due to trauma is one of the most common musculoskeletal complaints. Injury patterns seen in children vary from those in adults. Clinical assessment of knee injuries may be difficult owing to severe pain, swelling, and joint effusion. Conventional radiology remains the primary imaging modality for children with knee pain, but many serious injuries will not be shown. In particular, most soft tissue abnormalities will not be seen; therefore, the value of radiography is often limited. MR imaging is an excellent modality for pediatric knee disorders because of its lack of ionizing radiation, multiplanar capabilities, soft tissue contrast, and high resolution providing accurate assessment of bone,cartilage, menisci, ligaments, andadjacent soft tissues. MR imaging should not be used as aroutinetestbecauseitcarriessignificantadditional cost, is associated with a potential delay in diagnosis and treatment, and, for younger children, is not exempt of risks attendant to selection or anesthesia. The main indications to perform MRimaging of the knee are clinical suspicion of suspected internal derangement or an occult fracture, persistent pain, refusal to bear weight, or hemarthrosis.
Gravitational-Wave Driven Instability of Rotating Relativistic Stars

A series of recent surprises appear dramatically to have improved the likelihood that the spin of rapidly rotating, newly formed neutron stars is limited by a nonaxisymmetric instability driven by gravitational waves — and that the emitted waves may be detectable. The first of these was the discovery that the r-modes, rotationally restored modes that have axial parity for spherical models, are unstable in perfect fluid models with arbitrarily slow rotation. First indicated in numerical work by Andersson, 1) the instability is implied in a nearly newtonian context by the newtonian expression for the r-mode frequency (3.1), and a computation by Friedman and Morsink 19) of the canonical energy of initial data showed (independent of assumptions on the existence of discrete modes) that the instability is a generic feature of axial-parity perturbations of relativistic stars. Studies of the viscous and radiative timescales associated with the rmodes, 38), 43), 2), 29), 37) have revealed a second surprising result: The growth time of r-modes driven by current-multipole gravitational radiation is significantly shorter than had been expected, so short, in fact, that the instability to gravitational radiation reaction easily dominates viscous damping in hot, newly formed neutron stars (see Fig. 1 below). As a result, a neutron star that is rapidly rotating at birth now appears likely to spin down by radiating most of its angular momentum in gravitational waves. (See, however, the caveats below.) Nearly simultaneous with these theoretical surprises was the discovery by Marshall et al. 41) of a fast (16ms) pulsar in a supernova remnant (N157B) in the Large Magellanic Cloud. Estimates of the initial period put it in the 6-9ms range, implying the existence of a class of neutron stars that are rapidly rotating at birth. Hence,
Policy Statement of the International Organization for Medical Physics

Over the past few years papers have appeared in the scientific literature that predict thousands of cancers and cancer deaths each year in populations of patients receiving medical imaging procedures (primarily computed tomography) employing ionizing radiation. The predictions in these papers are computed by estimating very small and hypothetical risks at low radiation doses and multiplying these speculative estimates by large numbers of patients experiencing medical imaging. The public media use these papers to develop print and electronic news releases that raise anxiety in parents, families and patients, at times causing them to delay or defer needed imaging procedures. Decisions to delay or defer examinations constitute real risks to patients, as contrasted with the hypothetical risks presented in the papers. Professional organizations, including the American Association of Physicists in Medicine and the Health Physics Society, have developed policy positions in an effort to illuminate the controversy over the risks of low-level radiation exposures (see URLs in the supporting documents and additional readings). Scientific advisory groups such as the International Commission on Radiological Protection, the National Council on Radiation Protection and Measurements, and the United Nations Scientific Committee on the Effects of Atomic Radiation have also addressed the controversy (see URLs in the supporting documents and additional readings). Now the International Organization for Medical Physics, representing 80 national and six regional medical physics organizations and 18,000 medical physicists worldwide, has developed its own policy statement which is reproduced below. One can only hope that the policy statements issued by these knowledgeable organizations will have some deterrent influence on the continued propagation of unsupportable cancer risk estimates related to medical imaging procedures conducted with minimum doses of radiation consistent with high quality studies.
Risky Investment Decisions: How Are Individuals Influenced by Their Groups?

We investigate the effect of group versus individual decision-making in the context of risky investment decisions in which all subjects are fully informed of the probabilities and payoffs. Although there is full information, the lottery choices pose cognitive challenges so that people may not be sure of their expected utility-maximizing choice. Making such decisions in a group context provides real-time information in which group members can observe others' choices and revise their own decisions. Our experimental results show that simply observing what others in the group do has a significant impact on behavior. Coupling real-time information with group decisions based on the median value, i.e., majority rule, makes the median investment choice focal, leading people with low values to increase investments and those with high values to decrease investments. Group decisions based on the minimum investment amount produce more asymmetric effects.
EMBEDDING TANGLES IN LINKS

Extending and reproving a recent result of D. Krebes, we give obstructions to the embedding of a tangle in a link.
A transformed framework for dynamic correlation in multireference problems

We describe how multireference dynamic correlation theories can be naturally obtained as single-reference correlation theories in a canonically transformed frame. Such canonically transformed correlation theories are very simple and involve identical expressions to their single-reference counterparts. The corresponding excitations involve quasiparticles rather than the bare particles of the system. High-order density matrices (or their approximations) and the numerical metric instabilities common to multireference correlation theories do not appear. As an example, we formulate the Bogoliubov canonically transformed version of second-order Moller-Plesset perturbation theory and demonstrate its performance in H2, H2O, N2, and BeH2 bond dissociation.
On the need for a popular formal semantics

The technology transfer from semantics research to mainstream computing has been hampered by specialization of techniques at the expense of calculational clarity. A "popular semantics" is proposed as a remedy.
Tethered aerothermodynamic research needs

It is widely recognized that there exist significant gaps in our understanding of the aerothermodynamics of flow in regimes that are both hypersonic and rarefied. We refer here principally to flows of orbital velocity at altitudes of 90 km and above. In this paper, we identify and discuss needs for new information essential to progress on problems of design and computation for flight in these regimes. Measurement requirements implied by research needs are discussed in the context of a tethered research satellite. This vehicle is of the approximate mass and general sophistication of the proposed TSS-2. Recent estimates of drag, and tether and vehicle temperature, provide background materials for the discussion.
A Few Endpoint Geodesic Restriction Estimates for Eigenfunctions

We prove a couple of new endpoint geodesic restriction estimates for eigenfunctions. In the case of general 3-dimensional compact manifolds, after a TT* argument, simply by using the L 2-boundedness of the Hilbert transform on $${\mathbb{R}}$$ , we are able to improve the corresponding L 2-restriction bounds of Burq, Gerard and Tzvetkov (Duke Math J 138:445–486, 2007) and Hu (Forum Math 6:1021–1052, 2009). Also, in the case of 2-dimensional compact manifolds with nonpositive curvature, we obtain improved L 4-estimates for restrictions to geodesics, which, by Holder’s inequality and interpolation, implies improved L p -bounds for all exponents p ≥ 2. We do this by using oscillatory integral theorems of Hormander (Ark Mat 11:1–11, 1973), Greenleaf and Seeger (J Reine Angew Math 455:35–56, 1994) and Phong and Stein (Int Math Res Notices 4:49–60, 1991), along with a simple geometric lemma (Lemma 3.2) about properties of the mixed-Hessian of the Riemannian distance function restricted to pairs of geodesics in Riemannian surfaces. We are also able to get further improvements beyond our new results in three dimensions under the assumption of constant nonpositive curvature by exploiting the fact that, in this case, there are many totally geodesic submanifolds.
Nanocrystalline Soft Magnetic Alloys for Space Applications

This study focuses on a Co-based nanocrystalline alloy (Co84.55Fe4.45Zr7B4) with potential for long-term high temperature use. As an indication of their performance, core losses were measured on toroidal samples using a Walker AC permeameter over a frequency range of 0.1 to 500 kHz, at induction amplitudes of 100, 300, and 500 mT, and temperatures from 22 to 300°C. For a given frequency and maximum induction amplitude, the losses were invariant as a function of measurement temperature. Vibrating sample magnetometry provided the magnetization and hysteretic losses as a function of temperature. As the temperature of the alloy was raised to 300°C from room temperature, the saturation magnetization (120 emu/g)was reduced by less than 15%. A toroid was aged at 300°C for up to 300 hours and core loss measured as a function of aging time at the previously mentioned frequencies and induction amplitudes. The losses were invariant over the aging time.
Powerful Flares from Recoiling Black Holes in Quasars

Mergers of spinning black holes can give recoil velocities from gravitational radiation up to several thousand km s−1. A recoiling supermassive black hole in an AGN retains the inner part of its accretion disk. Marginally bound material rejoining the disk around the moving black hole releases a large amount of energy in shocks in a short time, leading to a flare in thermal soft X-rays with a luminosity approaching the Eddington limit. Reprocessing of the X-rays by the infalling material gives strong optical and ultraviolet emission lines with a distinctive spectrum. Despite the short lifetime of the flare (~104 yr), as many as 102 flares may be in play at the present time in QSOs at redshifts ~1-3. These flares provide a means to identify high-velocity recoils.
Understanding the Chandra Detected X-ray Emission of the Knots and Hot Spots of Powerful Extragalactic Jets

I present here a short personal view of our understanding of the Chandra detected knots and hot spots of powerful Fanaroff Rilley (FR) II radio galaxies and quasars in the context of leptonic models. Observations of the knots and hot spots strongly suggest that the jets in these powerful sources retain their relativistic velocities at large scales, all the way to the hot spots. The emission mechanism suggested for the knots of quasars and FR II radio galaxies is external Compton (EC) off the cosmic microwave backgounrd (CMB) from a relativistic flow, while for the hotspots Upstream Compton (UC) scattering from a decelerating relativistic flow.
Strong Redshift Clustering of Distant Galaxies

We present initial results from a redshift survey carried out with the Low Resolution Imaging Spectrograph on the 10 m W. M. Keck Telescope of a field 14.6 arcmin2 in solid angle. In the redshift distribution of the 106 extragalactic objects in this sample we find five strong peaks, with velocity dispersions of ~500 km s-1. There is evidence for a nonuniform areal density of objects in at least two peaks. These peaks have characteristics (velocity dispersions, density enhancements, spacing, and spatial extent) similar to those of nearby galaxy structures (e.g., walls and clusters), and these are expected in a survey of this kind. We suggest that the prominence of these structures in our survey relative to that in other surveys can be attributed to our K selection and dense sampling.
Multiple functions for Mcm2-7 ATPase motifs during replication initiation.

Summary The Mcm2–7 replicative helicase is central to all steps of eukaryotic DNA replication. The hexameric ring of Mcm subunits forms six essential ATPases whose contributions to replication initiation remain unclear. Mcm2–7 complexes containing ATPase-motif mutations showed Mcm2–7 ATP binding and hydrolysis are required for helicase loading. Loading-defective Mcm2–7 mutant complexes were defective in initial Mcm2–7 recruitment or Cdt1 release. Comparison with Cdc6 ATPase mutants showed that Cdc6 ATP hydrolysis is not required for helicase loading but instead drives removal of Mcm2–7 complexes that cannot complete loading. A subset of Mcm2–7 ATPase-site mutants completed helicase loading but could not initiate replication. Individual mutants were defective in distinct events during helicase activation, including maintenance of DNA association, recruitment of the GINS helicase activator, and DNA unwinding. Consistent with its heterohexameric structure, our findings show that the six Mcm2–7 ATPase active sites are specialized for different functions during helicase loading and activation.
Ligand-enabled meta -C–H activation using a transient mediator

Achieving site selectivity in C-H functionalization reactions is a significant challenge, especially when the target C-H bond is distant from existing functional groups. Coordination of a functional group to a metal is often a key driving force and control element in many important reactions including asymmetric hydrogenation, epoxidation and lithiation. Exploitation of this effect has led to the development of a broad range of directed C-H activation reactions. However, these C-H activation methods are limited to proximal C-H bonds, which are spatially and geometrically accessible from the directing functional group. The development of meta-selective C-H functionalizations remains a significant challenge. We recently developed a U-shaped template that can be used to overcome this constraint and have shown that it can be used to selectively activate remote meta-C-H bonds. Although this approach has proved to be applicable to various substrates and catalytic transformations, the need for a covalently attached, complex template is a substantial drawback for synthetic applications. Here we report an alternative approach employing norbornene as a transient mediator to achieve meta-selective C-H activation with a simple and common ortho-directing group. The use of a newly developed pyridine-based ligand is crucial for relaying the palladium catalyst to the meta position by norbornene after initial ortho-C-H activation. This catalytic reaction demonstrates the feasibility of switching ortho-selectivity to meta-selectivity in C-H activation of the same substrate by catalyst control.
Charge-state distributions of 100, 175, 275 and 352 MeV gold ions emerging from thin carbon foils

Abstract Ion charge-state distributions were measured for 100, 175, 275 and 352 MeV gold ions emerging from thin carbon foils. The 90° double-focusing energy analyzing magnet of the Holifield Heavy Ion Research Facility 25 MV tandem accelerator was used to separate the charge-states. Carbon foil thicknesses of 10, 20, 40 and 80 μg/cm 2 were used depending on the beam energy. At least two different foil thicknesses were used at each energy to insure that equilibrium distributions were measured. The measured mean charge was compared with the predictions of the Sayer, Nikolaev-Dmitriev, and Shima et al. semi-empirical charge-distribution formulas. The measurements are in general agreement with the semi-empirical predictions at 100 MeV but were systematically lower at the higher energies. The largest discrepancy was −4.9 charge-states at 352 MeV. These results are especially significant for the design of booster accelerators for large tandem accelerators and for the design of coupled cyclotron systems.
Pediatric Stress Echocardiography

Traditional health evaluations are performed while the patient is at rest. Stress echocardiography extends these examinations by providing data in a physiologic setting more closely mimicking the typically active state of children. The test represents a fusion of the fields of two-dimensional echocardiography and cardiovascular stress testing and can be used to assess myocardial perfusion in patients with suspected coronary artery pathology or to evaluate cardiac gradients or functional reserve in patients with noncoronary artery pathology. Testing should be performed with a trained sonographer and attending physician and in collaboration with adult cardiology colleagues. Stress can be administered to the patient through either exercise or pharmacologic agents. Echocardiography is used to assess regional wall motion abnormalities when evaluating myocardial perfusion or gradients and/or function when assessing the patient without coronary artery issues. Conditions with potential coronary artery pathology for which stress echocardiography is appropriate include Kawasaki disease, transplant graft vasculopathy, arterial switch operation for transposition of the great arteries, anomalous coronary artery origins or courses, pulmonary atresia with intact ventricular septum, hyperlipidemia, insulin-dependent diabetes mellitus, and supravalvar aortic stenosis. Stress echocardiography can also be helpful in determining the behavior during activity of gradients in conditions such as hypertrophic cardiomyopathy or aortic and pulmonic stenosis, of cardiac pressures in pulmonary hypertension and of ventricular function in conditions such as dilated cardiomyopathy or mitral and aortic regurgitation.
DETECTION OF THERMAL EMISSION OF XO-2b: EVIDENCE FOR A WEAK TEMPERATURE INVERSION

We estimate flux ratios of the extrasolar planet XO-2b to its host star XO-2 at 3.6, 4.5, 5.8, and 8.0 μm with Infrared Array Camera on the Spitzer Space Telescope to be 0.00081 ± 0.00017, 0.00098 ± 0.00020, 0.00167 ± 0.00036, and 0.00133 ± 0.00049, respectively. The fluxes provide tentative evidence for a weak temperature inversion in the upper atmosphere, the precise nature of which would need to be confirmed by longer wavelength observations. XO-2b substellar flux of 0.76 × 109 erg cm–2 s–1 lies in the predicted transition region between atmospheres with and without upper atmospheric temperature inversion.
THE IMPACT OF FARM CREDIT IN PAKISTAN

Both informal and formal loans matter in agriculture. However, formal lenders provide many more production loans than informal lenders, often at a cost (mostly loan default cost) higher than what they can recover. For example, the Agricultural Development Bank of Pakistan (ADBP), providing about 90% of formal loans in rural areas, incurs high loan default costs. Yet, like other governments, the Government of Pakistan supports the formal scheme on the grounds that lending to agriculture is a high risk activity because of covariate risk. Hence, such policies are often based on a market failure argument. As farm credit schemes are subsidised, policy makers must know if these schemes are worth supporting. Using a recent large household survey data from rural Pakistan (Rural Financial Market Studies or RFMS), we have attempted to estimate the effectiveness of the ADBP as a credit delivery institution. A two-stage method that takes the endogeneity of borrowing into account is used to estimate credit impact. Results reveal that ADBP contributes to household welfare and that its impact is higher for smallholders than for large holders. Nevertheless, large holders receive the bulk of ADBP finance. The ADBP is, thus, not a cost-effective institution in delivering rural finance. Its cost-effectiveness can be improved by reducing its loan default cost and partially by targeting smallholders in agriculture where credit yields better results.
Axisymmetric thermal stresses in sandwich shells of revolution.

Reissner variational formulation of temperature distribution boundary value problem of axisymmetric thermal stresses in isotropic sandwich shells of revolution
A lower bound for the dimension of the base locus of the generalized theta divisor

Abstract We produce a lower bound for the dimension of the base locus of the generalized theta divisor Θ r on the moduli space SU C ( r ) of semistable vector bundles of rank r and trivial determinant on a smooth curve C of genus g ⩾ 2 . To cite this article: D. Arcara, C. R. Acad. Sci. Paris, Ser. I 340 (2005).
CoMMA: a framework for integrated multimedia mining using multi-relational associations

Generating captions or annotations automatically for still images is a challenging task. Traditionally, techniques involving higher-level (semantic) object detection and complex feature extraction have been employed for scene understanding. On the basis of this understanding, corresponding text descriptions are generated for a given image. In this paper, we pose the auto-annotation problem as that of multi-relational association rule mining where the relations exist between image-based features, and textual annotations. The central idea is to combine low-level image features such as color, orientation, intensity, etc. and corresponding text annotations to generate association rules across multiple tables using multi-relational association mining. Subsequently, we use these association rules to auto-annotate test images.In this paper we also present a multi-relational extension to the FP-tree algorithm to accomplish the association rule mining task effectively. The motivation for using multi-relational association rule mining for multimedia data mining is to exhibit the potential accorded by multiple descriptions for the same image (such as multiple people labeling the same image differently). Moreover, multi-relational association rule mining can also benefit the auto-annotation process by pruning the number of trivial associations that are generated if text and image features were combined in a single table through a join. In this paper, we discuss these issues and the results of our auto-annotation experiments on different test sets. Another contribution of this paper is highlighting a need to develop robust evaluation metrics for the image annotation task. We propose several applicable scoring techniques and then evaluate the performance of the different algorithms to study the utility of these techniques. A detailed analysis of the datasets used and the performance results are presented to conclude the paper.
New results on exotic mesons from BNL-E852

Abstract We have so far found evidence for two exotic mesons with the quantum numbers I G J PC = 1 − 1 −+ at masses 1.4 and 1.6 GeV. They are seen in the decay channels πη, πϱ and πη′ with varying degrees of strengths.
Significance of particle parameters in the evaluation of exposure-dose-response relationships of inhaled particles

Chronic rat inhalation studies have shown that a number of different panicle types can induce significant adverse effects, including impaired lung clearance, chronic pulmonary inflammation, pulmonary librosis, and lung tumors. These effects occurred when highly insoluble particles of low solubility and low cytotoxicity were inhaled in long-term studies. Inhaled concentrations ranged from a few milligrams per cubic meter up to 250 mg/m3. This wide range of inhaled concentrations may indicate that the particulate compounds have differed largely in their toxicity. This view appears to be supported by the fact that cytotoxic crystalline SiO2 shows very similar effects after much lower inhaled concentrations. However, although administered doses are customarily expressed in units of mass, this may not be the appropriate dose-metric for a correlation with observed effects. For example, effects on alveolar macrophage (AM) mediated clearance of particles could best be correlated with the volumetric lung burden of...
Synthesis of 1-aryl-5-(trifluoromethyl)-1H-pyrazole-4-carboxylic acids and esters

Ethyl 1-aryl-5-(trifluoromethyl)-1H-pyrazole-4-carboxylates 2 were prepared by the condensation of arylhydrazines with ethyl 3-ethoxy-2-(trifluoroacetyl)-2-propenoate (1a) at low temperature. The corresponding acids were also synthesized. X-ray diffraction analysis of an amide derivative 4 verified the position of the trifluoromethyl group on the pyrazole ring.
Variability of Neptune

Earth based observers of Neptune found that the planet varies in brightness at various wavelengths in ways that suggest that changes occur in the planet's atmosphere on several different time-scales. Global inhomogeneities in high altitude haze distribution that are stable for several days permit measurements of the planet's rotation period (about 18 hours), but this stability sometimes breaks down, obscuring the diurnal lightcurve. In addition, there is an apparent long term variability of the brightness of Neptune in anticorrelation with the cycle of solar activity. This slow variability of low amplitude may be punctuated by outbursts of high altitude condensation of particles in the atmosphere, whose decay time is several months.
Synthesis and transannular diels-alder reactions of (E,E,E)-cyclotetradeca-2,8,10-trienones

Abstract (E,E,E)-Cyclotetradeca-2,8,10-trienones 4 and 5 , prepared by intramolecular Horner-Wadsworth-Emmons reactions, undergo highly stereoselective transannular Diels-Alder reactions to the trans-anti-cis tricyclic ketones 6 and 7 , respectively.
Synthesis and characterization of mono-, bis-, tris- and tetrakis(trimethylsilylmethyl)silanes: (Me3SiCH2)xSiH4−x (x = 1−4)

Abstract The mono-, bis-, tris-, and tetrakis(trimethylsilylmethyl)silanes, (Me3SiCH2)xSiH4−x (x = 1−4), have been prepared for use as “models” of the various Si-centered functional units in a complex, highly branched polycarbosilane polymer of the approximate composition, “(SiH2CH2)n”. These compounds have been characterized by GC, IR, 1H, 13C, 29Si NMR, MS, and elemental analysis. The IR and NMR data for this series of compounds show distinct trends on increasing substitution, which are related to the structural differences within the series.
Using the small-world model to improve Freenet performance

Efficient data retrieval in an unstructured peer-to-peer system like Freenet is a challenging problem. In this paper, we study the impact of workload on the performance of Freenet. We find that there is a steep reduction in the hit ratio of document requests with increasing load in Freenet. We show that a slight modification of Freenet's routing table cache replacement scheme (from LRU to a replacement scheme that enforces clustering in the key space) can significantly improve performance. Our modification is based on intuition from the small-world models and theoretical results by Kleinberg; our replacement scheme forces the routing tables to resemble neighbor relationships in a small-world acquaintance graph--clustering with light randomness. Our simulations show that this new scheme improves the request hit ratio dramatically while keeping the small average hops per successful request comparable to LRU. A simple, highly idealized model of Freenet under clustering with light randomness proves that the expected message delivery time in Freenet is O(log n) if the routing tables satisfy the small-world model and have the size θ(log2n).
Calculational Tools for the Evaluation of Nuclear Cross-Section and Spectra Data

Abstract Continued improvements in the calculational methods for obtaining nuclear reaction cross sections and spectra provide indispensable tools for nuclear data evaluations.
Simultaneous optical and X-ray high-speed photometry of Cyg X-2

The X-ray emission from X-ray binaries may originate in flares occurring when magnetic loops anchored in the disc reconnect. In analogy with our Sun, Ha emission should arise as the accelerated electrons thermalize in the optically emitting disc, perhaps leading to correlated variability between X-rays, Ha and the optical continuum. We present simultaneous X-ray and optical high-speed photometry of the neutron star low-mass X-ray binary Cyg X-2 to search for such correlations. The highest time resolution achieved is 5 ms in white light and 100 ms with a 3-nm filter centred on Ha. We find power on time-scales >∼ 100 s (flickering) in optical with a total rms of a few per cent, about an order of magnitude less than that seen in X-rays. We do not find significant correlations between the X-ray and optical fluxes on short time-scales, and hence cannot conclude whether magnetic flares contribute significantly to the optical emission.
Viscoelastoplastic Response of Axisymmetric Shells under Impulsive Loadings

A derivation of finite element equations of and solution to the viscoelastoplastic response of an isotropic axisymmetric shell are presented herein. The generalized Maxwell model is incorporated into the von Mises isotropic yield function. This permits a derivation of the incremental stress as a function of elastic, viscous, and plastic strains. With this relationship inserted into the incremental equation of motion, a direct numerical integration scheme is then used to solve for incremental responses. The plastic tangent stiffness matrix is updated at each incremental time step. Numerical results are presented for a circular plate to verify correctness of the program and subsequently for a spherical cap subjected to uniformly distributed transverse impulsive load of infinite duration.
A Cartesian Grid Embedded Boundary Method for Poisson's Equation on Irregular Domains

We present a numerical method for solving Poisson's equation, with variable coefficients and Dirichlet boundary conditions, on two-dimensional regions. The approach uses a finite-volume discretization, which embeds the domain in a regular Cartesian grid. We treat the solution as a cell-centered quantity, even when those centers are outside the domain. Cells that contain a portion of the domain boundary use conservative differencing of second-order accurate fluxes on each cell volume. The calculation of the boundary flux ensures that the conditioning of the matrix is relatively unaffected by small cell volumes. This allows us to use multigrid iterations with a simple point relaxation strategy. We have combined this with an adaptive mesh refinement (AMR) procedure. We provide evidence that the algorithm is second-order accurate on various exact solutions and compare the adaptive and nonadaptive calculations.
Stock Prices, Real Exchange Rates, and Optimal Capital Accumulation

The dynamics of the real exchange rate and the price of equity for a small open economy are analyzed using an optimizing model in which the process of capital accumulation entails adjustment costs. The analysis demonstrates how changes in fiscal policies or world interest rates can generate sustained movements in real exchange rates and equity prices simply because investment requires scarce resources. Interpreting such movements as evidence of market inefficiencies would be incorrect since adjustment is driven entirely by equilibrium in asset and goods markets. The results, however, do indicate that a stable and consistent set of fiscal policies can help reduce unnecessary volatility in real exchange rates and equity prices.
A demographic analysis of the family structure experiences of children in the United States

This paper analyzes the family structure experiences of children in the U.S. Childbearing and transitions among single, cohabiting, and married states are analyzed jointly. A novel contribution is to distinguish men by their relationship to children: biological father or stepfather. The analysis uses data from the NLSY79. A key finding is that children of black mothers spend on average only 33% of their childhood living with the biological father and mother, compared to 74% for children of white mothers. The two most important proximate demographic determinants of the large racial gap are the much higher propensity of black women to conceive children outside of a union, and the lower rate of “shotgun” unions for blacks compared to whites. Another notable finding is that cohabitation plays a negligible role in the family structure experiences of children of white mothers, and even for children of black mothers accounts for less than one fifth of time spent living with both biological parents.
On the Unusually High Temperature of the Cluster of Galaxies 1E 0657-56

A recent X-ray observation of the cluster 1E 0657-56 (z = 0.296) with ASC,4 implied an unusually high temperature of approx. 17 keV. Such a high temperature would make it the hottest known cluster and severely constrain cosmological models since, in a Universe with critical density (Omega = 1) the probability of observing such a cluster is only approx. 4 x 10(exp -5). Here we test the robustness of this observational result since it has such important implications. We analysed the data using a variety of different data analysis methods and spectral analysis assumptions and find a temperature of approx. 11 - 12 keV in all cases, except for one class of spectral fits. These are fits in which the absorbing column density is fixed at the Galactic value. Using simulated data for a 12 keV cluster, we show that a high temperature of approx. 17 keV is artificially obtained if the true spectrum has a stronger low-energy cut-off than that for Galactic absorption only. The apparent extra absorption may be astrophysical in origin, (either intrinsic or line-of-sight), or it may be a problem with the low-energy CCD efficiency. Although significantly lower than previous measurements, this temperature of kT approx. 11 - 12 keV is still relatively high since only a few clusters have been found to have temperatures higher than 10 keV and the data therefore still present some difficulty for an Omega = 1 Universe. Our results will also be useful to anyone who wants to estimate the systematic errors involved in different methods of background subtraction of ASCA data for sources with similar signal-to-noise to that of the IE 0657-56 data reported here.
Liability for Past Environmental Contamination and Privatization

This paper examines the role ofliability for past environmental contaminationin the privatization processes of Central andEastern Europe. In particular, it establishes alink between a risk-averse investor's amount ofinformation regarding the extent of pastenvironmental contamination (and its cleanupcosts) and the investor's willingness to payfor a particular enterprise, i.e., bid. As theinvestor obtains a more precise estimate of theuncertain cleanup costs, the investor facesless risk; therefore, the investor's riskpremium falls and the investor's bid rises.This link generates four hypotheses regarding aprivatization agency's responses to theinvestor's knowledge of clean-up costs.
New Paradigm for the Isotope Scaling of Plasma Transport Paradox

Most tokamak experimental results [M. Bessenrodt-Weberpals et al., Nucl. Fusion 33, 1205 (1993)] and basic physics experiments [V. Sokolov and A. K. Sen, Phys. Rev. Lett. 89, 095001 (2002)] in the Columbia Linear Machine indicate dependence of the ion thermal conductivity on the isotopic mass close to ${\ensuremath{\chi}}_{\ensuremath{\perp}}\ensuremath{\sim}{A}_{i}^{\ensuremath{-}0.5}$, i.e., inverse gyro-Bohm. This is in stark contradiction to most present theoretical models predicting Bohm (${A}_{i}^{0}$) or gyro-Bohm (${A}_{i}^{0.5}$) scaling. A series of experiments designed to explore the physics basis of this scaling appears to lead to a new model for this scaling based on 3-wave coupling of two ion temperature gradient radial harmonics and an ion acoustic wave.
Saddlepoint approximations for affine jump-diffusion models

Abstract Affine jump-diffusion (AJD) processes constitute a large and widely used class of continuous-time asset pricing models that balance tractability and flexibility in matching market data. The prices of e.g., bonds, options, and other assets in AJD models are given by extended pricing transforms that have an exponential-affine form; these transforms have been characterized in great generality by Duffie et al. [2000. Transform analysis and asset pricing for affine jump-diffusions. Econometrica 68, 1343–1376]. Calculating model prices requires inversion of these transforms, and this has limited the application of AJD models to the comparatively small subclass for which the transforms are available in closed form. This article seeks to widen the scope of AJD models amenable to practical application through approximate transform inversion techniques. More specifically, we develop the use of saddlepoint approximations for AJD models. These approximations facilitate the calculation of prices in AJD models whose transforms are not available explicitly. We derive and test several alternative saddlepoint approximations and find that they produce accurate prices over a wide range of parameters.
Direct Reductive Amination of Aldehyde Bisulfite Adducts Induced by 2-Picoline Borane: Application to the Synthesis of a DPP-IV Inhibitor

Aldehyde-bisulfite adducts dervied from unstable parent aldehydes were reductively alkylated in a direct fashion with a variety of amines. This approach features the use of 2-picoline borane as the reducing agent and a protic solvent for the reaction media and has been successfully applied to the synthesis of a DPP-IV inhibitor and a variety of other amines.
Metallic Thermal-Protection-System Panel Flutter Study.

Panel flutter analysis results of a reusable launch vehicle metallic thermal protection system [Ref.l] panel are presented in this paper. Panel flutter is a self-excited aeroelastic vibration. The unsteady aerodynamic theory used in this study is the first- and second-order piston theory. The analysis capability is incorporated into a commercial finite element code with the goal of providing a useful tool for aerospace engineers —MSC/MARC [Ref.6]. The capability consists of three parts: linear flutter analysis, linear flutter analysis with arbitrary flow direction, and nonlinear hypersonic flutter analysis. Structural nonlinearities are not considered. The current paper covers both panel flutter analysis tool development as well as parametric panel flutter study of a specific metallic TPS configuration. The resulting analytical tool was used to analyze a metallic TPS being built for the X-33 experimental vehicle. The results show that nonlinear, hypersonic aerodynamic terms were found to have an insignificant effect on the panel flutter predictions for the X-33 TPS. The honeycomb sandwich that comprises most of the outer surface of the X-33 TPS panel was found to have large margins of safety for panel flutter for all flight conditions. However, the outer overlapping, panel-to-panel seals were predicted
Simulation of Cavity Flow by the Lattice Boltzmann Method

A detailed analysis is presented to demonstrate the capabilities of the lattice Boltzmann method. Thorough comparisons with other numerical solutions for the two-dimensional, driven cavity flow show that the lattice Boltzmann method gives accurate results over a wide range of Reynolds numbers. Studies of errors and convergence rates are carried out. Compressibility effects are quantified for different maximum velocities and parameter ranges are found for stable simulations. The paper's objective is to stimulate further work using this relatively new approach for applied engineering problems in transport phenomena utilizing parallel computers.
Q0906+6930: The Highest Redshift Blazar

We report the discovery of a radio-loud flat-spectrum QSO at z = 5.47 with properties similar to those of the EGRET γ-ray blazars. This source is the brightest radio QSO at z > 5, with a parsec-scale radio jet and a black hole mass estimate 1010 M☉. It appears to be the most distant blazar discovered to date. High-energy observations of this source can provide powerful probes of the background radiation in the early universe.