cssi/SciSciGPT-SciSciNet huggingface dataset:
Mangicols: Structures and Biosynthesis of A New Class of Sesterterpene Polyols from a Marine Fungus of the Genus Fusarium

A marine fungal isolate, tentatively identified as Fusarium heterosporum, has been found to produce a series of structurally novel sesterterpene polyols, the mangicols A-G (4-10). The structures of the new compounds, including the stereochemistry of mangicol A, were assigned by interpretation of spectral data derived from both natural products and synthetic derivatives. The mangicols, which possess unprecedented spirotricyclic skeletal components, show only weak to modest cytotoxicities toward a variety of cancer cell lines in in vitro testing. Mangicols A and B, however, showed significant antiinflammatory activity in the PMA (phorbol myristate acetate)-induced mouse ear edema model. A biosynthetic pathway for the neomangicol and mangicol carbon skeletons is proposed on the basis of the incorporation of appropriate radiolabeled precursors.
A framework for viewing atomic events in distributed computations

Events in a distributed computation have been implicitly modeled in the literature in the isolated contexts of various applications. This paper presents a unifying framework for expressing and analyzing events at various levels of atomicity in a distributed computation. In the framework, events at any level of atomicity are defined and composed in terms of events at a finer level of atomicity using hierarchical views of the distributed computation. We identify and prove three properties that are satisfied by each level of atomicity. Results based on these properties that hold for any one level of atomicity apply to all levels of atomicity. The properties also show that the global states at the various levels of atomicity correspond to embedded lattices of global states, thereby providing different abstract views of the same computation.
Restless Bandits, Linear Programming Relaxations, and a Primal-Dual Index Heuristic

We develop a mathematical programming approach for the classicalPSPACE-hard restless bandit problem in stochastic optimization. We introduce a hierarchy ofN (whereN is the number of bandits) increasingly stronger linear programming relaxations, the last of which is exact and corresponds to the (exponential size) formulation of the problem as a Markov decision chain, while the other relaxations provide bounds and are efficiently computed. We also propose a priority-index heuristic scheduling policy from the solution to the firstorder relaxation, where the indices are defined in terms of optimal dual variables. In this way we propose a policy and a suboptimality guarantee. We report results of computational experiments that suggest that the proposed heuristic policy is nearly optimal. Moreover, the second-order relaxation is found to provide strong bounds on the optimal value.
The juxtaposition and spatial disconnect of environmental justice declarations and actual risk: A new method and its application to New York State

Abstract Some states are defining environmental justice areas geographically on the basis of demographic criteria alone. This is problematic as it does not consider distributive concentrations of environmental toxins. Although environmental justice is much more than avoiding concentrations of increased environmental risk, the identification of such areas could provide states with a roadmap for addressing concentrations and for the facilitation of appropriate community-targeted programs in response. This research proposes an applied quantitative approach for the geographic designation of areas determined to be at greater relative risk of exposure to environmental toxins as part of states' broader environmental justice goals and policies. Using the U.S. Environmental Protection Agency's Risk Screening Environmental Impact Tool (RSEI) and spatial analyses, the proposed method defines geographic areas reflecting calculated risk values pertaining to exposed populations and toxic releases. The method is applied to four counties of New York, and the results are juxtaposed with current state-declared environmental justice areas, which are defined on demography alone. This approach permits geospatial mapping and exploratory spatial data analysis. The method potentially can be used by states to effectively address concentrations of toxic releases as part of their environmental justice programs and policies.
Tax‐Exempt Organization Financial Data: Availability and Limitations

Historically, information about tax‐exempt organizations has often been hard to obtain. The 1996 tax act requires a tax‐exempt organization to provide a copy of its informational Form 990 to anyone who requests it and specifies penalties for noncompliance. Form 990 information on most tax‐exempt organizations is also being made available in digitized form. The ready availability of such financial information will subject nonprofit reporting to greater scrutiny than ever before. Accountants need to be aware that preparer error rates may become public information. This paper describes recent developments that are making Form 990 data available to researchers and the general public. It then discusses potential uses for the data as well as limitations of the data, and considers possible implications for nonprofit managers, donors and accounting firms.
New Light on Copenhagen and the German Nuclear Project

The recent release of draft letters from Niels Bohr to Werner Heisenberg provides new insights into German fission research during World War II and into the reasons for its relative failure. I refute claims of deliberate failure and briefly summarize other contributing factors.
Pricing multivariate contingent claims using estimated risk–neutral density functions

Abstract Many asset price series exhibit time-varying volatility, jumps and other features inconsistent with assumptions about the underlying price process made by standard multivariate contingent claims (MVCC) pricing models. This article develops an interpolative technique for pricing MVCCs — flexible NLS pricing — that involves the estimation of a flexible multivariate risk–neutral density function implied by existing asset prices. As an application, the flexible NLS pricing technique is used to value several bivariate contingent claims dependent on foreign exchange rates in 1993 and 1994. The bivariate flexible risk–neutral density function more accurately prices existing options than the bivariate log-normal density implied by a multivariate geometric Brownian motion. In addition, the bivariate contingent claims analyzed have substantially different prices using the two density functions suggesting flexible NLS pricing may improve accuracy over standard methods.
A simple and regioselective synthesis of 13C-methyl-labeled thymidine.

Abstract A convenient and efficient procedure for the synthesis of 13C methyl-labeled thymidine by way of lithiation of t-butyldimethylsilyl protected 2′-deoxyuridine is described.
Aeroelastic Tailoring of Forward Swept Composite Wings

A set of closed-form solutions to idealized static aeroelastic problems is presented. These solutions describe the effects of fibrous composites on flexible lifting surface divergence, lift effectiveness, and spanwise center-ofpressure location. Several examples illustrate the ability of aeroelastic tailoring to modify spanwise center-ofpressure location. Additional examples, using data generated from a matrix method of analysis, show that tailoring for forward swept wing divergence is likely to be effective out to relatively high aspect ratios and that lateral control effectiveness can be enhanced considerably by fibrous composite tailoring.
Optimal reduced-order state estimation for unstable plants

The problem of optimal reduced-order steady-state state estimation is considered for the case in which the plant has unstable poles. In contrast to the standard full-order estimation problem involving a single algebraic Riccati equation, the solution to the reduced-order problem involves one modified Riccati equation and one Lyapunov equation coupled by a projection matrix. This projection is completely distinct from the projection obtained by Bernstein and Hyland (1985) for stable plants.
A general and mild synthesis of thioesters and thiols from halides

Abstract The conversion of a wide variety of halides to thioesters by reaction with potassium thiocetate under mild conditions is described, and the generality of the method is demonstrated.
The effect of discharge chamber wall temperature on ion thruster performance

Experiments conducted on a ring cusp ion thruster that could be maintained at temperatures in the range 80 K to 500 K during operation by cooling it with liquid nitrogen are described. The measured changes in performance induced by discharge chamber wall temperature changes are compared to those predicted by a simple discharge chamber model. Good agreement between the temperature induced effects predicted by the model and measured results are demonstrated. Decreases in wall temperature to about 90 K are shown to effect substantial improvements in performance.
From the Laboratory to the Clinic: A Retrospective on Fully Synthetic Carbohydrate‐Based Anticancer Vaccines

This review provides an account of our explorations into oligosaccharide and glycoconjugate construction for the creation and evaluation of vaccines based on carbohydrate-centered tumor antigens. Our starting point was the known tendency of transformed cells to express selective carbohydrate motifs in the form of glycoproteins or glycolipids. Anticancer vaccines derived from carbohydrate-based antigens could be effective targets for immune recognition and attack. Obtaining significant quantities of such structures from natural sources is, however, extremely difficult. With the total synthesis of tumor-associated carbohydrate antigens accomplished, we began to evaluate at the clinical level whether the human immune system can respond to such fully synthetic antigens in a focused and useful way. Toward this goal, we have merged the resources of chemistry and immunology in an attack on the problem. The synthesis and immunoconjugation of various tumor-associated carbohydrate antigens and the results of such constructs in mice vaccinations will be described. For fashioning an effective vaccine, conjugation to a suitable immunogenic carrier was necessary and conjugates of KLH (keyhole limpet cyanin) have consistently demonstrated the relevant immunogenicity. Preclinical and clinical studies with synthetic conjugate carbohydrate vaccines show induction of IgM- and IgG-antibody responses. Another approach to anticancer vaccines involves the use of clustered glycopeptides as targets for immune attack. Initial attention has been directed to mucin related O-linked glycopeptides. Synthetic trimeric clusters of glycoepitopes derived from the Tn-, TF- and Lewis(y)-antigens, appropriately bioconjugated, have been demonstrated to be immunogenic. The hope is that patients immunized in an adjuvant manner with synthetic carbohydrate vaccines would produce antibodies reactive with cancer cells and that the production of such antibodies would mitigate against tumor spread, thereby enabling a more favorable survival and "quality of life" prognosis.
Internet Shopping Agents: Virtual Co-Location and Competition

Internet Shopping Agents (ISAs) allow consumers to costlessly search many online retailers and buy at the lowest price. One would expect these ISAs to subject sellers to intense price competition that results in uniform low prices. Yet, Internet retailers have joined these ISAs. Furthermore, the prices charged by inside retailers can vary substantially. We examine the impact of ISAs on market competition. An ISA creates differentiation in the pricing strategies of ex-ante identical retailers: Some retailers join the ISA due to mass of consumers that they can potentially win, while others stay out and extract surplus from their loyal consumers, while others stay our and extract surplus from their loyal consumers. The equilibrium inside pricing is such that the average price charged can increase or decrease when more retailers join, depending on whether or not the reach of the ISA is independent of the number of joining retailers. When the reach is endogenous, there exist a unique number of inside retailers.
Determining the Grain Composition of the Interstellar Medium with High-Resolution X-Ray Spectroscopy

We investigate the ability of high-resolution X-ray spectroscopy to directly probe the grain composition of the interstellar medium. Using iron K-edge experimental data of likely ISM dust candidates taken at the National Synchrotron Light Source at Brookhaven National Laboratory and the Advanced Photon Source at Argonne National Laboratory, we explore the prospects for determining the chemical composition of astrophysical dust and discuss a technique for doing so. Focusing on the capabilities of the Astro-E2 XRS microcalorimeters, we assess the limiting effects of spectral resolution and noise for detecting significant X-ray absorption fine structure signal in astrophysical environments containing dust. We find that given sufficient signal, the resolution of the XRS will allow us to definitively distinguish gas-phase from dust-phase absorption and certain chemical compositions.
Controversy about agricultural technology lessons from the green revolution

The development and introduction of transgenically modified organisms to enhance crop and animal production has generated considerable controversy about potential food safety and environmental impacts. The introduction, in tropical Latin America and Asia, of high yielding varieties of wheat, maize and rice beginning in the late 1960s was also controversial. Critics argued that the new technology was biased against the poor - it would make the rich richer and the poor poorer. In this paper I review the equity and productivity impacts of the 'green revolution' technology and draw several inferences about evaluation of the effects of the new biotechnologies in agricultural production.
Radiation reaction forces and the expanding universe

Abstract The expanding universe is described in terms of the known forces of classical physics. It is shown that great clouds of stars are non-conservative systems and that radiation reaction forces play a part in guiding stellar motions. The forces are of importance in unsymmetrical stars and evidence is collected to show that perhaps all stars are possessed of deep seated thermal asymmetries. The forces continually act to increase the mean velocity of the stars and the galaxy is calculated to expand at a rate which closely approximates the observed rate of expansion. From a relation connecting the mean velocity of the stars and their age, it is deduced from the observed motions that the age of the galaxy is about 1010 years. The deduced rate of expansion of the galaxy agrees well with the observational data and is identical in form and numerical constant with Hubble's relation connecting the velocity of recession and distances of nebulae. Because of the relative size and spacing of the extra galactic nebulae and the short time scale it is supposed that the nebulae were formed by fission from a parent-super nebula and this resulted in thermal asymmetries which brought the newly considered forces into action.The resulting expansion was produced by slow evolutionary radiation processes which bear no direct relation to the properties of space or atomic constants. The calculations suggest that in describing the motions of typical stars over long periods of time, radiation reaction forces are as important as the classical gravitational forces.
Thermochemistry of Perovskite-related oxides with high oxidation states: Superconductors, sensors, fuel cell materials

Perovskite-related oxides containing transition metals (Mn, Fe, Co, Ni, Cu) in high formal oxidation states are important materials as high temperature superconductors, electrochemical sensors and solid oxide fuel cell electrodes. High oxidation states are stabilized by large alkaline earth ions, Ba and Sr. Recent study by high temperature reaction calorimetry has revealed systematics in both enthalpies of formation and of oxygen incorporation in these materials. The enthalpy of formation from the oxides of a series of ternary oxides containing formal Cu3+ becomes increasingly exothermic with decreasing ionic potential, chargehize, of the counterbalancing cation, that is, in the series LaCuOg , LaSrCuOq, LaBaCuOq, NaCu02, KCu02. The enthalpy of oxygen incorporation becomes more exothermic in the sequence M = Ca, Sr, Ba for the series MxLa2-xCu04-y. The oxidation enthalpy is similar for Ba-doped lanthanum cuprates and for YBCO. This enthalpy is similar to that of the formation of the corresponding alkaline earth peroxide for both Ba and Sr, suggesting an energetic and possibly also structural relation between hole states in these multicomponent oxides and in peroxides. The doped lanthanum nickelates and cobaltates show more exothermic oxidation energetics than the cuprates. The overall energetics are governed by the competition of oxygen vacancy formation, oxidation to formal M3+, and coupled ionic substitution. Energetic parameters for these defect formation reactions are derived from calorimetric data.
Diastereospecific synthesis of ketooxindoles. Potential intermediates for the synthesis of alstonisine as well as for Voachalotine related oxindole alkaloids

Abstract A convenient method has been developed to convert NaH tetracyclicketone 1a into the two corresponding oxindoles[C(7)] diastereospecifically. Treatment of the NaH, Nb-benzyl tetracyclicketone 1a with t-BuOCl provided diastereomer 2a (related to Voacanga oxindoles), whereas the same process with NbH (1b) or Nb-benzoyl (1c) substituted analogs funished the diastereomers 2b and 2c (related to alstonisine), respectively.
Effects of stress and strain on scintillating and clear fibers

Among the improvements planned for the 1997-98 upgrade of the DO detector at Fermilab are installation of a scintillating-fiber central tracker and a lead-scintillator central preshower counter read out with wave-shifting fibers. Because of space limitations, fibers in both systems may need to undergo bends with fairly small radii, and the resulting stresses and strains may cause light losses. This paper presents results of a study of the effects of deformation on fiber light transmission. Particular emphasis is placed on the new multiclad fibers developed by Kuraray. >
Diameter and Velocity Effects for Cross-Flow Boiling

The effect of heater diameter on the pool and flow boiling heat transfer of Freon-113 was studied. The heaters were horizontal copper tubes of diameter 1.59-7.94 mm (pool) and 3.18-12.7 mm (flow), heated internally by condensing steam. The test fluid at atmospheric pressure flowed upward, normal to the heaters, at approach velocities of 2.4, 4.0, and 6.0 m/s. For flow boiling, at a fixed velocity and wall temperature, smaller tubes resulted in higher heat flux values, except at low wall temperatures. The maximum heat flow was proportional to the 0.44 power of velocity and inversely proportional to the 0.28 power of diameter. In pool boiling the critical diameter was different for different regimes of boiling and depended on the characteristic bubble size. For tubes smaller than this critical diameter, the heat flux increased as the tube size decreased for a fixed wall temperature. Tubes larger than the critical diameter showed no diameter effect on the heat flux, except for transition boiling. For transition boiling, the heat flux increased as the tube diameter increased beyond the critical diameter.
Direct Moat Isolation for VLSI

Device isolation is a major factor in determining the circuit packing density in VLSI. The scalability of device isolation by local oxidation of silicon (LOCOS) is limited by the large encroachment, including both physical and electrical, into the active device area resulting from lateral oxidation (bird's beaking) at the edge of isolation oxide and channel stop diffusion into the active device region. An alternative isolation technique is to form the active device area by patterning a thick field oxide uniformly grown or deposited on the silicon substrate. Such a direct moat isolation scheme makes more efficient use of the silicon area by reducing encroachment considerably and thus allowing closer packing of active devices than the LOCOS approach. Direct moat isolation process approaches for VLSI design rules are discussed. Short-channel effects on the subthreshold characteristics of the parasitic devices are studied using a two-dimensional model and compared with experimental measurements. Good device isolation is demonstrated in a parasitic device with a field oxide thickness of 550 nm and a minimum moat-to-moat spacing of 2 /spl mu/m.
Product set estimates for non-commutative groups

We develop the Plunnecke-Ruzsa and Balog-Szemeredi-Gowers theory of sum set estimates in the non-commutative setting, with discrete, continuous, and metric entropy formulations of these estimates. We also develop a Freiman-type inverse theorem for a special class of 2-step nilpotent groups, namely the Heisenberg groups with no 2-torsion in their centre.
Oxaziridine-Mediated Catalytic Hydroxylation of Unactivated 3° C−H Bonds Using Hydrogen Peroxide

The design, structural characterization, and evaluation of a unique class of 1,2,3-benzoxathiazine-based oxaziridines as potent O-atom transfer agents for catalytic C−H hydroxylation and alkene epoxidation are described. Turnover of this reaction is made possible by employing a diaryl diselenide cocatalyst and urea·H2O2 as the terminal oxidant. Oxidation of saturated hydrocarbons is strongly biased toward 3° C−H bonds even in systems possessing a significantly greater number of methylene groups. In addition, the benzoxathiazine catalyst is effective for epoxidation of terminal and electron-deficient olefins. Collectively, these findings represent an important first step toward the advancement of general methodology for selective C−H oxidation.
Injury surveillance in a pediatric emergency department.

In this study we have tried to determine physician success in the collection of injury data during the emergency department visit. Prospective data were collected from all children between the ages of 0 to 18 treated for an injury. Data were collected at the time of the visit and by chart review the next day. At an urban, university-affiliated, children's hospital, data were collected on 2,156 injured children. Fifty-one percent of the data forms were completed by the treating physician. Physician completion rate was lower on the weekends (46%) than on weekdays (52%, P = .02). The most common mechanisms of injury were falls (34%), motor-vehicle crashes or pedestrians struck (13%), and nonintentional struck by blunt object (12%). The most common mechanism of injury in all age groups was falls. Our results demonstrate that emergency physicians are not successful data collectors. However, when physician data collection is combined with next-day review of patient records, virtually 100% of patients are captured. Active emergency department data collection is important because in contrast to studies which use hospital discharge and mortality data, we found that overall falls account for more injuries presenting to the ED than transportation-related causes. An active surveillance system in emergency departments that does not require extra work on the part of the treating physician would be ideal and may give a more comprehensive description of the scope of the injury problem.
Agency costs, asset specificity, and the capital structure of the firm

Abstract We develop a dynamic model that incorporates the insights of both the agency cost and asset specificity literature about corporate finance. In general, we find that neither can be ignored, and that the optimal capital structure minimizes agency cost and asset specificity considerations. A key finding is that the conditions most favorable for reducing transaction costs due to asset specificity are the same as those for reducing the agency costs of debt. Empirically, we find that agency costs and asset specificity are significant determinants of a firm’s capital structure in the transportation equipment and the printing and publishing industries.
Picturing qubits in phase space

Focusing particularly on one-qubit and two-qubit systems, I explain how the quantum state of a system of n qubits can be expressed as a real function--a generalized Wigner function--on a discrete 2n ?? 2n phase space. The phase space is based on the finite field having 2n elements, and its geometric structure leads naturally to the construction of a complete set of 2n + 1 mutually conjugate bases.
Estimation of Geothermal Brine Viscosity

Viscosity of synthetic brines consisting of sodium chloride, potassium chloride, and calcium chloride were measured at concentrations ranging from 0.99 to 16.667 wt% and at temperatures up to 275/sup 0/C. From the use of laboratory-derived data, a method is presented whereby the viscosity of a geothermal brine may be estimated from a knowledge of its composition.
An evaluation of electromagnetic methods in the presence of geologic noise

An important element of electromagnetic (EM) prospecting is survey design; numerical modeling algorithms may be used to calculate signal‐to‐geologic‐noise (S/N) ratios to compare different survey configurations and measured responses quantitatively. Our models consist of a prismatic three‐dimensional (3-D) target in a conductive half‐space which may contain an overburden conductor; the models are energized by a time‐varying current transmitted in a loop of wire. The signal is the scattered or anomalous response of the target, while the geologic noise is either the response of the half‐space or the anomalous response of the overburden conductor. For typical loop sizes in exploration, the coincident‐loop configuration has a relatively high S/N ratio and thus a relatively high capability to resolve the target in the case of half‐space noise. Measurements made with the horizontal‐loop, moving‐coil configuration can be just as effective if the coil separation is one and one‐half to two times the depth of buria...
Quantization of p-branes, D-p-branes and M-branes

Abstract Killing spinors of space-time BPS configurations play an important role in quantization of theories with the fermionic worldvolume local symmetry. We show here how it works for the CS superstring, BST supermembrane and M-5-brane. We show that the non-linear generalization of the (2,0) d=6 tensor supermultiplet action is the M-5-brane action in a Killing gauge. For D-p-branes the novel feature of quantization is that they can be quantized Lorentz covariantly, in particular, for D-0-brane a gauge exists where the action is covariant and free. We present a general condition on possible choice of gauges for the κ-symmetric branes.
Spin correlations in top-quark pair production at e + e - colliders

Abstract We show that top-quark pairs are produced in an essentially unique spin configuration in polarized e + e − colliders at all energies above the threshold region. Since the directions of the electroweak decay products of polarized top-quarks are strongly correlated to the top-quark spin axis, this unique spin configuration leads to a distinctive topology for top-quark pair events which can be used to constrain anomalous couplings to the top-quark. A significant interference effect between the longitudinal and transverse W-bosons in the decay of polarized top-quarks is also discussed. These results are obtained at leading order in perturbation theory but radiative corrections are expected to be small.
The Multiwavelength Approach to Unidentified Gamma-Ray Sources

As the highest-energy photons, gamma rays have an inherent interest to astrophysicists and particle physicists studying high-energy, nonthermal processes. Gamma-ray telescopes complement those at other wavelengths, especially radio, optical, and X-ray, providing the broad, mutiwavelength coverage that has become such a powerful aspect of modern astrophysics. Multiwavelength techniques of various types have been developed to help identify and explore unidentified gamma-ray sources. This overview summarizes the ideas behind several of these methods.
Oxidation of L-Proline methyl ester derivatives with the iodosylbenzene/trimethylsilylazide reagent combination

Abstract Oxidation of a series of L-Proline derivatives with the (PhlO) n /TMSN 3 reagent combination is reported. Subsequent utilization of the 5-azido N-acyl functionality as a N-acyl iminium ion precursor is described.
Grand unified theories, topological defects, and ultrahigh-energy cosmic rays.

The ultrahigh-energy (UHE) proton and neutrino spectra resulting from collapse or annihilations of topological defects surviving from the GUT era are calculated. Irrespective of the specific process under consideration (which determines the overall normalization of the spectrum), the UHE proton spectrum always 'recovers' at approximately 1.8 x 10 exp 11 GeV after a partial Greisen-Zatsepin-Kuz'min 'cutoff' at approximately 5 x 10 exp 10 GeV and continues to a GUT-scale energy with a universal shape determined by the physics of hadronic jet fragmentation. Implications of our results are discussed.
Misperceiving Interactions Among Complements and Substitutes: Organizational Consequences

Systems composed of activity choices that interact in nonsimple ways can allow firms to create and sustain a competitive advantage. However, in complex systems, decision makers may not always have a precise understanding of the exact strength of the interaction between activities. Likewise, incentive and accounting systems may lead decision makers to ignore or misperceive interactions. This paper studies formally the consequences of misperceiving interaction effects between activity choices. Our results suggest that misperceptions with respect to complements are more costly than with respect to substitutes. As a result, firms should optimally invest more to gather information about interactions among complementary activities--e.g., concerning network effects--than about interactions among substitute activities. Similarly, the use of division-based incentive schemes appears to be more advisable for divisions whose products are substitutes than for divisions that produce complements. It is further shown that system fragility is not necessarily positively correlated with the strength ofthe interaction between choices. While systems of complements become increasingly fragile as the strength of interaction increases, systems of substitutes can become increasingly stable.
AGA's Approach to the Microbiome

Reflecting on the immense potential of the gut microbiome, the governing board created the AGA Center for Gut Microbiome Research and Education. In the coming years, we expect the microbiome discoveries to drive clinical advances. Dr Gail Hecht is active in this area and serves on the center’s scientific advisory board, which guides AGA’s strategic work in this area.
Application of the telegraph model to coda Q variations in southern California

We examine waveforms and data used to construct coda magnitude in southern California to estimate the spatial variation of coda Q and its dependence on frequency. Our analysis combined with independent borehole data suggests that coda is mainly generated by multiple scattering in the upper few kilometers of the crust where large impedance contrasts occur because of surface layering or fracturing. The ubiquitous observation that coda Q increases with frequency is explained as arising from multiple reverberations in the upper crust. We suggest that the telegraph model that has been successfully used to describe reflection seismogram multiples in the exploration industry may also apply to earthquakes. Under this model the apparent increase of Q with frequency is due to trapping of high-frequency energy in the upper crust. This behavior is expected if the associated reflector series has an exponential autocorrelation function, a feature of the telegraph model. At lower frequencies, trapping is less efficient. The combined effects give rise to an apparent absorption band that we suppose is superimposed on frequency-independent intrinsic attenuation. Maximum apparent attenuation occurs at wavelengths equal to the dimensions of the regions of upper crust that contain the scattering layers. At lower frequencies, trapping is less effective, and attenuation decreases as the longer-wavelength waves sample the deeper crust and upper mantle where because of overburden pressures, acoustic impedance contrasts are less extreme. By taking spectral ratios of coda waves to direct S, we estimate that intrinsic Q is high (∼3000) and that coda may be modeled as multiple scattered S waves in a region of anisotropic scattering. The exponential decay of the coda is a result of the perfectly reflecting surface of the Earth with backscattering from random near-surface layers causing progressive leakage and loss of energy downward into the more transparent lower crust and mantle.
A 60GHz 1V + 12.3dBm Transformer-Coupled Wideband PA in 90nm CMOS

We demonstrate a fully integrated 60GHz transformer-coupled two-stage differential power amplifier with single-ended input and output in 90nm digital CMOS with no RF process options. This work uses on-chip transformers for a 60GHz PA as an integrated CMOS solution. Operating from a IV supply, it achieves a ldB compressed output power of +9dBm and saturated power of +12.3dBm.
A wide area differential backup protection scheme for shipboard application

A new wide area differential protection (WADP) system is proposed to suit the need of the shipboard application where short cables make conventional backup schemes impractical. The close proximity of all the components in a shipboard power system makes communication less of an issue than in a land-based system. With an overall view of the protected system and by use of a differential search algorithm, a minimum fault isolation area is decided. A built-in confirmation mechanism avoids unnecessary or false tripping due to protection component failure. The principle of the WADP system is described in detail in this paper. Simulation results are shown for a small Shipboard Power System (SPS).
Model reduction in vehicle dynamics using importance analysis

Previous work by the authors developed a novel model reduction method, namely importance analysis, that offered a unique set of properties: concurrent dynamic and kinematic reduction, applicability to nonlinear systems, preservation of realisation, and trajectory dependence. This paper investigates the utility of importance analysis as a model reduction tool within the context of vehicle dynamics. To this end, a high-fidelity model of a High Mobility Multipurpose Wheeled Vehicle (HMMWV) is considered, and this model is reduced for three different scenarios. Reduction is achieved in both dynamics and kinematics while preserving the original definition and interpretation of state variables and parameters. Furthermore, the resulting reduced models are very different in terms of complexity, containing only what is necessary for their respective scenarios, and providing important insight and computational savings. The conclusion is that importance analysis can be an invaluable reduction tool in vehicle dynamic...
Proposed new concepts for an advanced search and rescue satellite system

Methods of reducing the forwarding time from COSPAS/SARSAT (Space System for Search of Distressed Vessels/Search and Rescue Satellite-Aided Tracking System) satellite passage until a location is supplied to the search and rescue (SAR) forces are studied. It is shown how supplemental use of geostationary satellites or institution off-polar ground stations can reduce the time delay from 62 min to 7 min. The tradeoff between the two approaches is their cost and complexity versus time delay reduction. Sample systems are developed here in order to examine the tradeoffs.
NETL Extreme Drilling Laboratory Studies High Pressure High Temperature Drilling Phenomena

The U.S. Department of Energy's National Energy Technology Laboratory (NETL) established the Extreme Drilling Laboratory to engineer effective and efficient drilling technologies viable at depths greater than 20,000 ft. This paper details the challenges of ultradeep drilling, documents reports of decreased drilling rates as a result of increasing fluid pressure and temperature, and describes NETL's research and development activities. NETL is invested in laboratory-scale physical simulation. Its physical simulator will have capability of circulating drilling fluids at 30,000 psi and 480°F around a single drill cutter. This simulator is not yet operational; therefore, the results will be limited to the identification of leading hypotheses of drilling phenomena and NETL's test plans to validate or refute such theories. Of particular interest to the Extreme Drilling Laboratory's studies are the combinatorial effects of drilling fluid pressure, drilling fluid properties, rock properties, pore pressure, and drilling parameters, such as cutter rotational speed, weight on bit, and hydraulics associated with drilling fluid introduction to the rock-cutter interface. A detailed discussion of how each variable is controlled in a laboratory setting will be part of the conference paper and presentation.
Adjunctive hysterectomy following radiation therapy for bulky carcinoma of the uterine cervix: Prognostic implications of tumor persistence

Twenty-five patients underwent adjunctive extrafascial hysterectomy 14-60 days following completion of external and intracavitary irradiation for bulky carcinoma of the uterine cervix. Review of the operative histopathology and correlation with subsequent patient outcomes suggests that morphologically persistent cancer is prognostically ominous and that cancer near the surgical margin is viable in the majority of instances.
On the electronic structure of planar fluorinated amines and phosphines

Abstract The lowest closed-shell singlet state of planar PF, has recently been shown to have a highest occupied molecular orbital of a 1′ symmetry, rather than the normally expected a 2″ symmetry found in planar NF, and related species. A simple orbital interaction diagram is presented here to rationalize this unusual state. The effects of HOMO-LUMO mixing on the inversion barriers of NF 3 , NCl 3 , PF 3 , PCl 3 , and AsF 3 , are also investigated, and it is found that such mixing significantly reduces the calculated inversion barriers for most of these species.
DESIGN METHODOLOGY OF BOUNDARY DATA STRUCTURES

In this paper we propose a universal data structure (UDS), termed as UDS, which will aid in the design of optimal boundary data structures. We later show, with the aid of some recently published data structures, that any data structure can be expressed as a special case of UDS. We demonstrate how the application of the optimality concepts of the UDS can lead us to the discovery of more efficient data structures than popular data structures. We also discuss two approaches for optimization. We show that a globally optimal data structure is better than a special purpose optimal data structure.
An Assessment of Module Cooling Enhancement With Thermoelectric Coolers

The trend towards increasing heat flux at the chip and module level in computers is continuing. This trend coupled with the desire to increase performance by reducing chip operating temperatures presents a further challenge to thermal engineers. We will provide an assessment of the potential for module cooling enhancement with thermoelectric coolers. A brief background discussion of thermoelectric cooling is provided citing some of the early history of thermoelectrics as well as more recent developments from the literature. An example analyzing cooling enhancement of a multichip module package with a thermoelectric cooler is discussed. The analysis utilizes closed form equations incorporating both thermoelectric cooler parameters and package level thermal resistances to relate allowable module power to chip temperature. Comparisons are made of allowable module power with and without thermoelectric coolers based upon either air or water module level cooling
1,4-diazabicyclo[2.2.2]octane-catalyzed self- and cross-condensation of α-acetylenic ketones

Abstract 3-Butyn-2-one condenses with itself in the presence of 0.1 molar equiv of Dabco providing 80% yield of E -3-(1-buten-3-yn-2-oxy)-buten-2-one. Substitution at the acetylene terminus prevents the condensation. However, such ketones can be condensed with terminal acetylenic ketones to provide the cross-coupled products in high yields.
Nucleation, growth and transformation of amorphous and crystalline solids condensing from the gas phase

The condensation of solids was investigated from the initial nucleation stage through continuous film growth, using evaporation and high-energy ion-beam sputtering. At all stages the kinetics of the nucleation process and the structural characteristics of the condensed phase (glassy, polycrystalline and monocrystalline) were defined. Although many condensates were explored, the specific system discussed is germanium condensing on a variety of amorphous and crystalline substrates. The kinetic behavior observed in crystalline deposits was found consistent with the accepted atomistic model for nucleation. This allowed determination of such nucleation parameters as: the activation energies of surface diffusion,Q d and adsorption,Q ad ,the critical nucleus size,n *, and others. Values of such parameters were found to be systematic functions of the kinetic energy and flux of incident particles and of the type and temperature of the substrate. Two flux and temperature dependent structural order transitions were observed in the very initial nucleation stages and found to coincide with corresponding transitions inn *. Correlation was also established between these transitions and two structural transitions occurring during continuous film growth. This was aided by the occurrence of all four transitions in intermediate condensation stages, i.e. prior to coalescence of nucleation clusters into continuous film. All results were very distinctly affected by the vapor state of the adsorbates, implying considerable correlation between condensation on solid surfaces and in a vapor.
Does the lunar surface still offer value as a site for astronomical observatories

Abstract Current thinking about the Moon as a destination has revitalized interest in lunar astronomical observatories. Once seen by a large scientific community as a highly enabling site, the dramatic improvement in capabilities for free-space observatories prompts reevaluation of this interest. Whereas the lunar surface offers huge performance advantages for astronomy over terrestrial sites, free-space locales such as Earth orbit or Lagrange points offer performance that is superior to what could be achieved on the Moon. While astronomy from the Moon may be cost-effective once infrastructure is there, it is in many respects no longer clearly enabling compared with free space.
DEFICIENCIES OF LATTICE SUBGROUPS OF LIE GROUPS

Let L be a lattice in a connected Lie group. We show that besides a few exceptional cases, the deficiency of L is nonpositive.
The Effect of the Interstellar Model on Star Formation Properties in Galactic Disks

We studied the effect of interstellar gas conditions on global galaxy simulations by considering three different models for the ISM. Our first model included only radiative cooling down to 300 K, our second model added an additional background heating term due to photoelectric heating, and our third model uses an isothermal equation of state with a temperature of 104 K and no explicit heating or cooling. Two common prescriptions for star formation are implemented in each case. The first is based on cosmological simulations with a low threshold for star formation but also a low efficiency. The second assumes that stars form only in high-density regions but with a higher efficiency. We also explore the effects of including feedback from Type II supernovae. We find that the different ISM types produce marked differences in the structure of the disk and temperature phases present in the gas, although inclusion of feedback largely dominates these effects. In particular, the size of the star-forming clumps was increased both by background heating and by enforcing an isothermal ISM. We also looked at the one-dimensional profiles and found that a lognormal probability distribution function (PDF) provides a good fit for all our simulations over several orders of magnitude in density. Overall, despite noticeable structural differences, the star formation properties in the disk are largely insensitive to ISM type and agree reasonably well with observations.
GrOWL: A tool for visualization and editing of OWL ontologies

In an effort to optimize visualization and editing of OWL ontologies we have developed GrOWL-a browser and visual editor for OWL that accurately visualizes the underlying DL semantics of OWL ontologies while avoiding the difficulties of the verbose OWL syntax. In this paper, we discuss GrOWL visualization model and the essential visualization techniques implemented in GrOWL.
Mg-doped Al-rich AlGaN alloys for deep UV emitters

Mg doped Al-rich AlGaN epilayers with Al content as high as 0.7 is needed for obtaining deep UV LEDs with wavelengths shorter than 300 nm. This is one of the most crucial layers in deep UV LEDs and plays an important role for electron blocking and affects the hole injection into the active layer. Not only is this layer critical for the efficiency of deep UV LEDs, it could also introduce long wavelength emission components in UV LEDs. However, it is difficult to obtain high quality Mg doped Al-rich AlGaN epilayers and the resistivity of the grown films is usually extremely high. We report here on the growth, optical and electrical properties of Mg doped Al 0.7Ga0.3N epilayers. Mg doped Al0.7Ga0.3N epilayers of high crystalline and optical qualities have been achieved after optimizing MOCVD growth conditions. Moreover, we have obtained a resistivity around 12,000 Ω cm (near the theoretical limit with Mg doping) at room temperature and confirmed p-type conduction at elevated temperatures for optimized Mg-doped Al 0.7Ga0.3N epilayers. The growth conditions of the optimized epilayer have been incorporated into deep UV LEDs with wavelength shorter than 300 nm. A significant enhancement in power output with a reduction in forward voltage, V f, was obtained by employing this optimized Mg doped Al0.7Ga0.3N epilayer as an electron blocking layer. The long wavelength emission components in deep UV LEDs were also significantly suppressed. The fundamental limit for achieving p -type Al-rich AlGaN alloys is also discussed.
Gene expression in giant-cell tumors.

Malignant transformation is thought to be associated with changes in the expression of a number of genes, and this alteration in gene expression is considered critical to the development of the malignant phenotype. In this study, gene expression in 8 samples of giant-cell tumor (GCT) of bone, as well as in bone at the site of osteoarthritis and in a variety of normal tissues, was determined at Gene Logic Inc (Gaithersburg, Md) with the use of Affymetrix GeneChip ® U_133 arrays containing approximately 40,000 genes/expressed sequence tags (ESTs). Gene-expression analysis was performed with the use of the Gene Logic GeneExpress ® Software System. Differences in gene expression between GCTs and bone were observed. In addition, genes expressed uniquely in GCTs among these and 519 samples from 20 other tissue types were identified. Some of the genes that were found to be overexpressed in GCTs, such as tartrate-resistant acid phosphatase and the lysosomal H + –transporting ATPase, are also expressed by osteoclasts. Osteoprotegrin ligand (OPGL) was also selectively overexpressed in GCTs. The genes found to be overexpressed in GCTs appear to reflect the genetic profile of osteoclast-lineage cells and also the genetic profile of an osteoclastogenic environment. The genes identified in this study may play a role in the pathogenesis of GCTs, confirm the likely importance of OPGL in GCT pathogenesis, and may indicate other possible targets to which antitumor therapy could be directed.