cssi/SciSciGPT-SciSciNet huggingface dataset:
A quality control model with learning effects

Abstract We present a model that extends a variant of the classic quality control/machine maintenance model by adding the concept of quality-based learning. The extension captures the idea that operators of a production process may be able to discover and eliminate defects in the system if, during an inspection, they find the process to be “out of control”. Thus, the distinguishing feature of the model is that one inspects the process not only for the purpose of riring the machine, but also in the hope that the machine will be caught in the act of producing defective output, so that a source of problems is uncovered and eliminated. The paper provides a characterization of optimal inspection policies and suggest the managerial implications: Ignoring the learning benefits of inspection and quality control activities may lead to underinvestment in quality improvement activities, which, in turn, may hinder both cost and quality competitiveness.
Dynamic stability testing of the Orbiter flight control system/flexible body interaction

A new kind of ground vibration test has been developed that yields results directly useful to flight control designers. Inputs are applied to vehicle controllers with the flight control system powered-up. Sensor outputs and system commands are analyzed to measure system transient and frequency response, which are then compared with predictions. An end-to-end evaluation of the validity of the design analysis is thus obtained prior to flight test. Flex body dynamics, sensor and controller characteristics, and system software are all covered. This paper describes the tests on Columbia in August 1980 and summarizes the results.
Elastic and Viscoelastic Calculations of Stresses in Sedimentary Basins

This study presents a method for estimating the stress state within reservoirs at depth with a time-history approach for both elastic and viscoelastic rock behavior. The model can incorporate changes in pore pressure, temperature gradients, consolidation and diagenesis through time-varying material properties, and varying tectonic episodes. Example calculations are presented for simple cases and for a complete stress history of rocks in the Piceance basin.
An Unexpectedly Swift Rise in the Gamma-Ray Burst Rate

The association of long gamma-ray bursts with supernovae naturally suggests that the cosmic GRB rate should trace the star formation history. Finding otherwise would provide important clues concerning these rare, curious phenomena. Using a new estimate of Swift GRB energetics to construct a sample of 36 luminous GRBs with redshifts in the range z = 0-4, we find evidence of enhanced evolution in the GRB rate, with ~4 times as many GRBs observed at -->z ? 4 than expected from star formation measurements. This direct and empirical demonstration of needed additional evolution is a new result. It is consistent with theoretical expectations from metallicity effects, but other causes remain possible, and we consider them systematically.
The Sloan Digital Sky Survey

Astronomy is about to undergo a major paradigm shift, with data sets becoming larger and more homogeneous, designed for the first time in a top-down fashion. The paper discusses the Sloan Digital Sky Survey. By digitally mapping half of the northern sky, this project promises to radically improve the way scientists do astronomy. In putting a digital sky on the desktops of astronomers, the SDSS could well lead to major new discoveries.
The Allocation of Control Rights in Venture Capital Contracts

Venture capitalists often hold extensive control rights over entrepreneurial companies, including the right to fire entrepreneurs. This article examines why, and under what circumstances, entrepreneurs would voluntarily relinquish control. Control rights protect the venture capitalists from hold-up by the entrepreneurs. This provides the correct incentives for the venture capitalists to search for a superior management team. Wealth-constrained entrepreneurs may give up control even if the change in management imposes a greater loss of private benefit to them than a monetary gain to the company. The model also explains why entrepreneurs accept vesting of their stock and low severance.
Great circle links and virtually fibered knots

We show that all two-bridge knot and link complements are virtually fibered. We also show that spherical Montesinos knot and link complements are virtually fibered. This is accomplished by showing that such manifolds are finitely covered by great circle link complements.
Distributional effects of carbon taxes: The case of Mexico

Abstract In this study, I develop an analytical general equilibrium model to assess the distributional effects across income groups of a carbon tax assuming that the revenue from the carbon tax is recycled in two different ways: as a manufacturing tax-cut and a food subsidy. I use this analytical model to provide intuition about the main distributional components. The model is calibrated with data from Mexico to obtain unambiguous price and quantity changes. I find that the distribution of the costs is driven by the way the revenue is recycled. In particular, the costs are distributed regressively when the revenue is recycled as a manufacturing tax cut and progressively when it is recycled as a food subsidy. Providing a food subsidy also generates higher welfare and lower carbon emissions than the manufacturing tax cut. To compare and test the robustness of the numerical findings for Mexico, I calibrate the model with data for a developed country, specifically the U.S.A. Despite differences in the magnitude of the changes in some variables, the general findings mentioned above also hold for U.S.A. data. These results suggest that, as found for the U.S.A. in recent studies, carbon taxes are not necessarily regressive. Rather, the way revenue is recycled is a major determinant of how the carbon tax costs are distributed.
Valuation‐based accounting research: Implications for financial reporting and opportunities for future research

This paper discusses the relation between financial reporting research and practice, particularly standard setters. Many studies addressing financial reporting issues use a valuation approach. The paper describes alternative approaches to valuation research and summarises the findings relating to four major current issues: fair value accounting for financial, tangible, and intangible assets, cash flows versus accruals, recognition versus disclosure, and international harmonisation of accounting standards. The summaries include identifying what standard setters and others would like to learn from research, what we have learned, and what is left to learn. The paper concludes with observations about future financial reporting academic research.
Exotic quantum order in low-dimensional systems

Abstract Strongly correlated quantum systems in low dimensions often exhibit novel quantum ordering. This ordering is sometimes hidden and can be revealed only by examining new “dual” types of correlations. Such ordering leads to novel collection modes and fractional quantum numbers. Examples will be presented from quantum spin chains and the quantum Hall effect.
A study of secondary ion triple bond analogues

Abstract Diatomic molecular ions isoelectronic with CN − have been generated in ion-implanted semiconductor materials and analyzed using secondary ion spectrometry (SIMS). Negative (IVA—VA) − ions containing the VA species from IV A-implanted IIIA—VA semiconductors are found to be produced more readily than the IV A − ions. The triple bond analogues studied were of the general types (IVA—VA) − , (IIIA—VIA) − , (VA—VIA) + and (IVA—VIIA) + . Molecular ion formation mechanisms and the analytical consequences of the results of this study are discussed.
A sequential metal-catalyzed C-N bond formation in the synthesis of 2-amido-indoles.

A sequential metal-catalyzed C−N bond formation employing ortho-haloaryl acetylenic bromides is described. The initial amidation is highly selective for Csp−N bond formation, leading to o-haloaryl-substituted ynamides that can be useful building blocks, while the overall sequence provides a facile construction of 2-amido-indoles.
A Vector Dual-Primal Finite Element Tearing and Interconnecting Method for Solving 3-D Large-Scale Electromagnetic Problems

This paper attempts to apply the idea of the FETI-DPH method together with the first-order absorbing boundary condition (ABC) to solve relatively large-scale problems using edge elements. The algorithm for nodal elements is adapted to edge elements to represent the tangential electric and magnetic fields without changing the main idea of the method. The resulting method is denoted as the FETI-DPEM method in this paper
Studies on the Catalytic-Oxidation of Alkanes and Alkenes by Titanium Silicates

Titanium containing, aluminum-free ZSM-5 (TS-1) and amorphous TiO_2-SiO_2 coprecipitate are investigated as catalysts for the selective oxidation of alkanes and alkenes using a variety of oxidants at temperatures below 100°C. Comparisons between the activities of TS-1 and the TiO2-SiO2 coprecipitate for alkane oxidation and alkene epoxidation using nonaqueous H_2O_2 indicate that the absence of water is crucial for the catalytic activity of silica-supported titanium. Due to the hydrophobicity of TS-1, the concentration of water surrounding the titanium is maintained at a low value, and thus TS-1 can be used as an oxidation catalyst with aqueous H_2O_2 as oxidant. Alkyl hydroperoxides are active as oxidants for alkene epoxidation on the TiO_2-SiO_2 coprecipitate but not for alkane oxidation reactions on both TS-1 and the TiO_2-SiO_2 coprecipitate. A plausible explanation for the above results is provided. The presence of stereoscrambling without any "radical clock" rearrangement during alkane oxidation on TS-1 indicates that the radicals formed may have a very short life-time, or their movements are restricted such that no rearrangement can occur. A proposal for the mechanism of alkane oxidation on TS-1 is given and compared to a mechanism suggested for alkene epoxidation on TS-1 and the TiO_2-SiO_2 coprecipitate.
Heavy Dust Obscuration of z = 7 Galaxies in a Cosmological Hydrodynamic Simulation

Hubble Space Telescope observations with the Wide Field Camera 3/Infrared reveal that galaxies at z ∼ 7 have very blue ultraviolet (UV) colors, consistent with these systems being dominated by young stellar populations with moderate or little attenuation by dust. We investigate UV and optical properties of the high-z galaxies in the standard cold dark matter model using a high-resolution adaptive mesh refinement cosmological hydrodynamic simulation. For this purpose, we perform panchromatic three-dimensional dust radiative transfer calculations on 198 galaxies of stellar mass 5 × 10{sup 8}-3 × 10{sup 10} M{sub ☉} with three parameters: the dust-to-metal ratio, the extinction curve, and the fraction of directly escaped light from stars (f{sub esc}). Our stellar mass function is found to be in broad agreement with Gonzalez et al., independent of these parameters. We find that our heavily dust-attenuated galaxies (A{sub V} ∼ 1.8) can also reasonably match modest UV-optical colors, blue UV slopes, as well as UV luminosity functions, provided that a significant fraction (∼10%) of light directly escapes from them. The observed UV slope and scatter are better explained with a Small-Magellanic-Cloud-type extinction curve, whereas a Milky-Way-type curve also predicts blue UV colors due to the 2175 A bump. Wemore » expect that upcoming observations by the Atacama Large Millimeter/submillimeter Array will be able to test this heavily obscured model.« less
The local density of halo giants

A new estimate of the local density of halo giants - 36 +/- 7 with M(V) less than 0.5 per cu kpc - is presented. This number is derived from an objective-prism survey for nearby metal-weak stars, and so is free from many of the assumptions needed to derive the local halo density in the traditional way, from high proper motion surveys. This number agrees well with estimates of the local density of halo horizontal-branch stars, but is approximately a factor of 2 smaller than the density derived by Bahcall and Casertano (1986). This may be due to the inclusion of some thick disk stars in their proper-motion selected sample. The halo density derived from giants can be expressed as a disk-to-halo ratio of 850:1 (+/- 35 percent). Using these results, a simple model is built to predict numbers of halo giants in specified directions in the Galaxy. It is shown that it performs much better than the Bahcall-Soniera model, in the specific case of halo giants. The surface brightness due to the halo at the solar radius is calculated to be 27.7 V magnitudes per sq arcsec, if the Galaxy was viewed from the outside, edge-on, thus raising the possibility of detecting light from halo field stars in other galaxies similar to our own.
An enantiodivergent approach to D- and L-erythrose via microbial oxidation of chlorobenzene

Abstract D- and L-erythrose derivatives have been synthesized from chlorobenzene, providing for the conversion of undesired pollutants to synthetically useful chiral intermediates . The overall yields of the title compounds are compared to known preparation from arabinoses.
Ground-Based Gamma Ray Astronomy

This paper is the write-up of a rapporteur talk given by the author at the 33rd International Cosmic Ray Conference in Rio de Janeiro, Brazil, in 2013. It attempts to summarize results and developments in ground-based gamma-ray observations and instrumentation from among the ∼300 submissions to the gamma-ray sessions of the meeting. Satellite observations and theoretical developments were covered by a companion rapporteur (Stawarz, L., 33rd ICRC, Rio de Janeiro, Brazil, Rapporteur talk: Space-based Gamma-Ray Astronomy, 2013). Any review of this nature is unavoidably subjective and incomplete. Nevertheless, the article should provide a useful status report for those seeking an overview of this exciting and fast-moving field.
Potential silicon-containing antifolates

Abstract Novel silicon-containing folate derivatives were synthesized as potential inhibitors of folate-dependent enzymes in an attempt to develop more effective antitumor agents. A dimethylsilyl moiety was inserted into the sidechain of two known antifolates with the aim of improving passive transport properties and sidechain conformational flexibility. An efficient, convergent palladium-catalyzed coupling methodology was used to link known heterocycles to novel, highly functionalized vinyl and ethynyl silanes.
The asymmetric Birch reduction and reduction–alkylation strategies for synthesis of natural products

Synthetic applications of the asymmetric Birch reduction and reduction–alkylation are reported. Synthetically useful chiral intermediates have been obtained from chiral 2-alkoxy-, 2-alkyl-, 2-aryl- and 2-trialkylsilyl-benzamides I and the pyrrolobenzodiazepine-5,11-diones II. The availability of a wide range of substituents on the precursor benzoic acid derivative, the uniformly high degree of diastereoselection in the chiral enolate alkylation step, and the opportunity for further development of stereogenic centers by way of olefin addition reactions make this method unusually versatile for the asymmetric synthesis of natural products and related materials.
String-nets, single- and double-stranded quantum loop gases for non-Abelian anyons

String-nets and quantum loop gases are two prominent microscopic lattice models to describe topological phases. String-net condensation can give rise to both Abelian and non-Abelian anyons, whereas loop condensation usually produces Abelian anyons. It has been proposed, however, that generalized quantum loop gases with non-orthogonal inner products could support non-Abelian anyons. We detail an exact mapping between the string-net and these generalized loop models and explain how the non-orthogonal products arise. We also introduce an equivalent loop model of double-stranded nets where quantum loops with an orthogonal inner product and local interactions supports non-Abelian Fibonacci anyons. Finally, we emphasize the origin of the sign problem in systems with non-Abelian excitations and its consequences on the complexity of their ground state wavefunctions.
FIELDS AND FIRST ORDER PERTURBATION EFFECTS IN TWO-DIMENSIONAL CONDUCTOR DOMINATED MAGNETS.

General expressions are given for the field and its expansion coefficients produced by a two dimensional conductor structure surrounded by iron with a circular inside boundary. Saturation effects are described in terms of the tangential field at that boundary. The effects of the following types of perturbations are discussed: displacement, rotation and error excitation of a conductor, change of conductor shape, and modification of the inside contour of the iron. A design criterion is given to minimize the error fields associated with a displacement of the iron shell relative to the conductor structure. Expressions for the force and torque acting on a conductor are derived both for the unperturbed and perturbed magnet. Formulae are presented that allow convenient and fast evaluation of pertinent quantities with a computer when the structure is too complicated for hand computations.
The Far-Ultraviolet Spectrum of the Io Plasma Torus

The spectrum of the Io plasma torus in the range 905-1187 A was recorded at 0.26 A resolution by the Far Ultraviolet Spectroscopic Explorer (FUSE) on 2001 January 14. Five orbits of data were obtained with the west ansa of the torus centered and tracked in the 30'' × 30'' apertures of the FUSE spectrographs for a total observation time of 9740 s. This region of the spectrum is dominated by transitions of S II, S III and S IV, whose multiplet structure is nearly completely resolved. We confirm our earlier detection of emission from resonance multiplets of Cl III and Cl II and derive an abundance of Cl+2 of 2.1% relative to S2+, leading to an overall chlorine ion abundance in the torus of slightly less than 1%. A number of features near 990 A remain unidentified, and C III λ977 is detected in two independent channels at the 3 σ level. The inferred relative ion abundance of C2+ relative to S2+ is 3.7 × 10-4. We also present spectra at 0.085 A resolution taken on 2001 October 19 and 21 with the 4'' × 20'' aperture. In these spectra, the observed lines are resolved, and their widths correspond to ion temperatures of 60-70 eV for all three sulfur ions.
Spectral Properties of the Renormalization Group at Infinite Temperature

The renormalization group (RG) approach is largely responsible for the considerable success that has been achieved in developing a quantitative theory of phase transitions. Physical properties emerge from spectral properties of the linearization of the RG map at a fixed point. This article considers RG for classical Ising-type lattice systems. The linearization acts on an infinite-dimensional Banach space of interactions. At a trivial fixed point (zero interaction), the spectral properties of the RG linearization can be worked out explicitly, without any approximation. The results are for the RG maps corresponding to decimation and majority rule. They indicate spectrum of an unusual kind: dense point spectrum for which the adjoint operators have no point spectrum at all, only residual spectrum. This may serve as a lesson in what one might expect in more general situations.
Long tunneling contact as a probe of fractional quantum Hall neutral edge modes

We study the tunneling current between edge states of quantum Hall liquids across a single long contact region, and predict a resonance at a bias voltage set by the scale of the edge velocity. For typical devices and edge velocities associated with charged modes, this resonance occurs outside the physically accessible bias domain. However, for edge states that are expected to support neutral modes, such as the $\nu={2/3}$, and $\nu={5/2}$ Pfaffian and anti-Pfaffian states, the neutral velocity can be orders of magnitude smaller than the charged mode and if so the resonance would be accessible. Therefore, such long tunneling contacts can resolve the presence of neutral edge modes in certain quantum Hall liquids.
A PTAS for Cutting Out Polygons with Lines

We present a simple O(m+n 6/e 12) time (1+e)-approximation algorithm for finding a minimum-cost sequence of lines to cut a convex n-gon out of a convex m-gon.
Structure and Ferromagnetism of the Rare-Earth Zintl Compounds: Yb14MnSb11 and Yb14MnBi11

Rare-earth transition metal compounds Yb14MnSb11 and Yb14MnBi11 have been prepared by heating stoichiometric amounts of the elements at 1000−1200 °C. These compounds are isostructural with the Zintl compound Ca14AlSb11 and crystallize in the tetragonal space group I41/acd (Z = 8). Single-crystal X-ray data (143 K) were refined for Yb14MnSb11 [a = 16.615(2) A, c = 21.948(4) A, V = 6059(2) A3, and R1/wR2 (0.0299/0.0479)] and Yb14MnBi11 [a = 17.000(3) A, c = 22.259(6) A, V = 6433(2) A3, R1/wR2 (0.0631/0.133)]. Structural analysis is consistent with Yb2+. Temperature-dependent magnetic susceptibility data show that Yb14MnSb11 orders ferromagnetically at 56 K and Yb14MnBi11 has a ferromagnetic transition at 58 K and another transition at 28 K. High-temperature magnetic susceptibility data can be fit with a modified Curie−Weiss law and give μeff = 4.92(2)μB and μeff = 4.9(1)μB for the Sb and Bi compounds, respectively. This result is consistent with the assignment of Mn3+ (d4) and Yb2+ (f 14). Single-crystal ma...
Synthesis of Aryl-Substituted Piperidines by Superacid Activation of Piperidones.

Diarylpiperidines (8−12) may be prepared in good to excellent yields (80−99%) by the reaction of piperidones (3d−h) with benzene and the Bronsted superacid, trifluoromethanesulfonic acid (CF3SO3H, TfOH). Tropinone (6) and quinuclidone (7) also react in good yields with benzene in TfOH to give the condensation products (13 and 14). Ketal and acetal derivatives also give condensation products (8 and 24) upon reaction with C6H6 in TfOH. The conversion of 3g to 11 is sensitive to both acid quantity and acid strength; a mechanism is proposed for the conversion that invokes dicationic intermediates.
Alkane Isomer Combinatorics: Stereostructure Enumeration and Graph-Invariant and Molecular−Property Distributions

Combinatoric manipulative methodology to characterize different isomer-class features is extended and illustrated in application to alkane isomers. Stereoisomeric enumerations and various molecular−property characteristics for structural-isomer classes are made. For a range of carbon-atom counts N we enumerate the following: the mean number of diastereomers per N-carbon structural isomer; the mean number of stereoisomers per N-carbon diastereomer; and the mean number of “conformers” per N-carbon stereoisomer. Also we consider distributions of several graph-theoretic properties, characterizing the distributions in terms of averages, variances, covariances, and extremal values. The results for these graph-theoretic invariants are used to predict (via substructural cluster expansion) some molecular properties (heats of formation and magnetic susceptibilities) averaged over these classes. The associated proper standard deviations as well as the extremal values for these cluster-expansion approximants are als...
The Laplacian lattice of a graph under a simplicial distance function

We provide a complete description of important geometric invariants of the Laplacian lattice of a multigraph under the distance function induced by a regular simplex, namely Voronoi Diagram, Delaunay Triangulation, Delaunay Polytope and its combinatorial structure, Shortest Vectors, Covering Radius and Packing Radius. We use this information to obtain the following results: i. We provide an explicit description of the vertices, edges and facets of the Delaunay polytope of the origin under the simplicial distance function and using the description, we show that the Delaunay triangulation contains complete information of the multigraph up to isomorphism. ii. A weak generalization of the matrix-tree theorem: the number of multigraphs with a given Laplacian lattice is controlled, in particular upper bounded, by the number of different Delaunay triangulations. iii. We obtain formulae for the covering and packing densities of a Laplacian lattice and deduce that in the space of Laplacian lattices of undirected connected multigraphs, the Laplacian lattices of highly connected multigraphs such as Ramanujan multigraphs possess high covering and packing properties in the space of Laplacian lattices of connected graphs.
Analysis of Jupiter’s Oval BA: A streamlined approach

We present a novel method of constructing streamlines to derive wind speeds within jovian vortices and demonstrate its application to Oval BA for 2001 pre-reddened Cassini flyby data, 2007 post-reddened New Horizons flyby data, and 1998 Galileo data of precursor Oval DE. Our method, while automated, attempts to combine the advantages of both automated and manual cloud tracking methods. The southern maximum wind speed of Oval BA does not show significant changes between these data sets to within our measurement uncertainty. The northern maximum dries appear to have increased in strength during this time interval, tvhich likely correlates with the oval's return to a symmetric shape. We demonstrate how the use of closed streamlines can provide measurements of vorticity averaged over the encircled area with no a priori assumptions concerning oval shape. We find increased averaged interior vorticity between pre- and post-reddened Oval BA, with the precursor Oval DE occupying a middle value of vorticity between these two.
Electronic and Nuclear Dynamics of the Accessory Bacteriochlorophylls in Bacterial Photosynthetic Reaction Centers from Resonance Raman Intensities

Resonance Raman spectra and absolute Raman scattering intensities of the Franck-Condon coupled vibrational modes of the accessory bacteriochlorophylls (B) in the photosynthetic reaction center from Rb. sphaeroides have been obtained with excitation in their 800 nm Qy absorption band. Although the relative Raman intensities are unchanged when the temperature is reduced from 278 to 95 K, the absolute Raman scattering intensity is found to increase by a factor of4 at 95 K. A self-consistent multimode vibronic model for the excitedstate properties of B has been developed that provides a unique fit to the absorption band and the Raman cross sections at both temperatures using a total S (linear electron-nuclear coupling factor) of 0.32 and an effective electronic dephasing time of54 fs at 278 K and210 fs at 95 K. The Raman scattering cross sections are consistent with an electronic structure model where the two B chromophores absorb and scatter independently. The Raman cross sections scale as 1/T 2 in the 95-298 K range, suggesting that the pure dephasing time, if modeled as a Gaussian (slow-modulation limit), decreases linearly with temperature. At room temperature, the electronic dephasing time is controlled by bath-induced dephasing processes rather than the energy transfer time from the excited state of B. The electronic and nuclear relaxation parameters derived here provide a more quantitative picture of the time scale and structural relaxation of the chromophores involved in energy transfer in reaction centers.
Numerical analysis of the Higgs mass triviality bound

Abstract Previous large N calculations are combined with numerical work at N =4 to show that the minimal standard model will describe physics to an accuracy of a few percent up to energies of the order two to four times the Higgs mass, M H , only if M H ⩽710±60 GeV. This bound is the result of a systematic search in the space of dimension-six operators and is expected to hold in the continuum . Given that studying the scalar sector in isolation is already an approximation, we believe that our result is sufficiently accurate and before further refinements are attempted their relevance to particle physics should be carefully considered.
Multi-stage robust unit commitment considering wind and demand response uncertainties

With the increasing penetration of wind power into the power grid, maintaining system reliability has been a challenging issue for ISOs/RTOs, due to the intermittent nature of wind power. In addition to the traditional reserves provided by thermal, hydro, and gas generators, demand response (DR) programs have gained much attention recently as another reserve resource to mitigate wind power output uncertainty. However, the price-elastic demand curve is not exactly known in advance, which provides another dimension of uncertainty. To accommodate the combined uncertainties from wind power and DR, we allow the wind power output to vary within a given interval with the price-elastic demand curve also varying in this paper. We develop a robust optimization approach to derive an optimal unit commitment decision for the reliability unit commitment runs by ISOs/RTOs, with the objective of maximizing total social welfare under the joint worst-case wind power output and demand response scenario. The problem is formulated as a multi-stage robust mixed integer programming problem. An exact solution approach leveraging Benders' decomposition is developed to obtain the optimal robust unit commitment schedule for the problem. Additional variables are introduced to parameterize the conservatism of our model and avoid over protection. Finally, we test the performance of the proposed approach using a case study based on the IEEE 118-bus system. The results verify that our proposed approach can accommodate both wind power and demand response uncertainties, and demand response can help accommodate wind power output uncertainty by lowering the unit load cost.
Studies of a C-band model function for friction velocity using coincident, simultaneous Ku-band scatterometer measurements

C-band scatterometer measurements during SWADE are being combined with coincident sea surface friction velocity estimates to create a new model function. The goal is to develop the capability of making friction velocity estimates (and surface stress) from radar cross section data acquired by the ERS-1 satellite scatterometer. Both Ku-band and C-band scatterometers were operated simultaneously for extensive intervals for each of 10 days during SWADE. The model function developed previously from FASINEX converts the Ku-band RCS measurements into friction velocity. The results show the C-band RCS dependence at 20, 30, 40 and 50 degrees to be less sensitive to friction velocity than the corresponding cases for Ku-band. Spatial variations of u* across the Gulf Stream are also studied in conjunction with supporting measurements of air-sea temperature and wind fields. >
Deriving a surrogate safety measure for freeway incidents based on predicted end-of-queue properties

Incidents can significantly impact freeway operations and deteriorate mobility and safety. This study quantified their safety impacts through inspecting queue properties. Specifically, the end-of-queue (EOQ), where severe rear-end collisions commonly occur, is employed for safety assessment based on vehicles' trajectories. Since detector data is typically available, this study applied such data for EOQ identification, as opposed to vehicle trajectories that are difficult to collect and process. Three measures related to queue duration, impact area and vehicle number exposed to the EOQ are presented as surrogates. To understand the applicability of these measures, a systematic set of incident scenarios is replicated with VISSIM. Quantitative results are used to estimate regression models, and significant variables are identified. The proposed methods can be used to evaluate safety impact of traffic incident management programs such as freeway service patrol, as well as to determine optimal plans for prearranged incidents such as pothole repair.
Attrition defenses for a peer-to-peer digital preservation system

In peer-to-peer systems, attrition attacks include both traditional, network-level denial of service attacks as well as application-level attacks in which malign peers conspire to waste loyal peers' resources. We describe several defenses for the LOCKSS peer-to-peer digital preservation system that help ensure that application-level attrition attacks even from powerful adversaries are less effective than simple network-level attacks, and that network-level attacks must be intense, widespread, and prolonged to impair the system.
Automatic thermal control switches

Two complementary types of flexible connection thermal control switches are described in detail. Both preflight and flight test results that demonstrate the successful operation of the switch that is presumed to have the more general application are presented. Finally, a more extensive postflight thermo-vacuum test that reveals the natural proportional control feature of the tested switch is included. The flight test of the switch was per- formed in the Get-Away Special (GAS) container which was flown on the third Shuttle flight. HE subject thermal switches have been designed and manufactured and the switch that is expected to have the more general application has been tested in a thermo-vacuum chamber and in the first flight of the GAS package on the third Shuttle flight (STS-3). Both switches are described, and the performance of the tested switch is given in detail. In- cidental to the thermal switch development was the development of the flexible heat pipes which are used as heat carriers in the tested switch. Space limitations preclude a discussion of the heat pipe development in this paper. Purpose of the Switches The objective of the thermal switch development program was to provide an off-the-shelf thermal control device that will: 1) control heat flow between any two adjacent structural components that are otherwise isolated from each other; 2) accommodate limited motion between the two components; 3) require no electric power; 4) need no outside control; 5) provide the maximum amount of self-containe d control logic; and 6) provide a thermal transport capacity of 5 to 50 W. Description of the Switches There are two types of switches (switch A and switch B), each of which is operated by a pair of phase change motors that exerts the required mechanical force when their tem- peratures exceed the phase change temperature of the working fluid within/The actuating motor is a special form (sealed for vacuum operation) of the phase change capsule used to control the coolant temperature in automobile engines. The switches are shown diagrammatica;ly in Figs. 1 and 2. These sketches are simplified to clarify the principles involved. Switch B (Fig. 2) is "closed" at low (below phase change) temperature so that heat will flow from the source plate (to which the connector is attached) through the heat carriers to the payload item to be thermally controlled (to which the switch is attached). This switch opens when the payload item exceeds the motor fluid phase change temperature and heat promptly ceases to flow. A typical application would have the connector of switch B attached to a space radiator, and the switch proper attached to a piece of internal structure. The purpose would be to allow heat (e.g., solar energy) to flow into the internal structure only until that structure reached the phase change control temperature of the switch. This would provide a regulated heat input to the payload item.
The impact of real estate agents on house prices near environmental disamenities

The purpose of this paper is to determine the impact of real estate agents on the price of houses that are located close to an environmental disamenity. Our main hypothesis is that real estate agents obtain higher prices than those theoretically expected when the houses are located closer to an environmental disamenity. We attribute this result to agents' ability to effectively match potential buyers to house sellers as well as their influence on bargaining power. Estimates from a sample selection corrected hedonic model suggest that the percentage increase in the house price obtained by a real estate agent is greater than the commission rate.
Synthesis and Characterization of Fluorodinitroamine, FN(NO2)2†

NF3 and N(NO2)3 are known compounds, whereas the mixed fluoronitroamines, FN(NO2)2 and F2NNO2, have been unknown thus far. One of these, FN(NO2)2, has now been prepared and characterized by multinuclear NMR and Raman spectroscopy. FN(NO2)2 is the first known example of an inorganic fluoronitroamine. It is a thermally unstable, highly energetic material formed by the fluorination of the dinitramide anion using NF4(+) salts as the preferred fluorinating agent.
CAN SPOT AND CONTRACT MARKETS CO-EXIST IN AGRICULTURE?

New production technologies, consumers who are more discriminating, and the need for improved coordination are among the forces driving the move from spot markets to contracts. Some worry that this tendency will result in the disappearance of spot markets, or at least that they will become too thin to be of help for an efficient price discovery process. Other authors point to the reduction in welfare of independent producers resulting from contracting in oligopsonistic industries. While a large body of literature is available tackling the contract versus spot market decision, much less is known about the reasons that lead to procurement in both markets. This paper provides a simple model to study how fundamental economic factors influence the contracting behavior of farmers and processors. In the model, processors contract upstream with price-taking farmers. Participation in both markets arises as a Nash equilibrium for a wide range of parameterizations. Numerical methods are used to examine the effects of fundamental economic factors on the relative size of the spot and contract markets.
Ultrafast electron diffraction (UED) a new development for the 4D determination of transient molecular structures

With properly timed sequences of ultrafast electron pulses, it is now possible to image complex molecular structures in the four dimensions of space and time with resolutions of 0.01 A and 1 ps, respectively. The new limits of ultrafast electron diffraction (UED) provide the means for the determination of transient molecular structures, including reactive intermediates and non-equilibrium structures of complex energy landscapes. By freezing structures on the ultrafast timescale, we are able to develop concepts that correlate structure with dynamics. Examples include structure-driven radiationless processes, dynamics-driven reaction stereochemistry, pseudorotary transition-state structures, and non-equilibrium structures exhibiting negative temperature, bifurcation, or selective energy localization in bonds. These successes in the studies of complex molecular systems, even without heavy atoms, and the recent development of a new machine devoted to structures in the condensed phase, establish UED as a powerful method for mapping out temporally changing molecular structures in chemistry, and potentially, in biology. This review highlights the advances made at Caltech, with emphasis on the principles of UED, its evolution through four generations of instrumentation (UED-1 to UED-4) and its diverse applications.
Independent evaluation of a simple clinical prediction rule to identify right ventricular dysfunction in patients with shortness of breath.

Abstract Background Many patients have unexplained persistent dyspnea after negative computed tomographic pulmonary angiography (CTPA). We hypothesized that many of these patients have isolated right ventricular (RV) dysfunction from treatable causes. We previously derived a clinical decision rule (CDR) for predicting RV dysfunction consisting of persistent dyspnea and normal CTPA, finding that 53% of CDR-positive patients had isolated RV dysfunction. Our goal is to validate this previously derived CDR by measuring the prevalence of RV dysfunction and outcomes in dyspneic emergency department patients. Methods A secondary analysis of a prospective observational multicenter study that enrolled patients presenting with suspected PE was performed. We included patients with persistent dyspnea, a nonsignificant CTPA, and formal echo performed. Right ventricular dysfunction was defined as RV hypokinesis and/or dilation with or without moderate to severe tricuspid regurgitation. Results A total of 7940 patients were enrolled. Two thousand six hundred sixteen patients were analyzed after excluding patients without persistent dyspnea and those with a significant finding on CTPA. One hundred ninety eight patients had echocardiography performed as standard care. Of those, 19% (95% confidence interval [CI], 14%-25%) and 33% (95% CI, 25%-42%) exhibited RV dysfunction and isolated RV dysfunction, respectively. Patients with isolated RV dysfunction or overload were more likely than those without RV dysfunction to have a return visit to the emergency department within 45 days for the same complaint (39% vs 18%; 95% CI of the difference, 4%-38%). Conclusion This simple clinical prediction rule predicted a 33% prevalence of isolated RV dysfunction or overload. Patients with isolated RV dysfunction had higher recidivism rates and a trend toward worse outcomes.
Nonequilibrium-dissociated stagnation boundary-layer flow on an arbitrarily catalytic swept wing

The aerodynamic heating of a swept stagnation line is examined in the high-altitude hypersonic flight regime where nonequilibrium dissociation/recombination in the boundary layer and finite surface catalysis effects are both important. Assuming a highly cooled body (T w /T s <<1), we extend Fay and Riddell's well-known self-similar solution for nonequilibrium-dissociated flow to include the effects of sweepback and arbitrary surface catalycity. Specific results for heat transfer are presented for the same zero sweep baseline case that was used in Fay and Riddell's work. In the frozen gas-phase limit, it is found that the combined net effects of sweep angle A wipe out the dissociation effects altogether beyond about Λ ≃ 65 deg and thus eliminate the usual favorable effect of a noncatalytic wall in reducing nonequilibrium heat transfer. Regarding the gas-phase chemistry aspect, results for a completely noncatalytic wall show that notwithstanding the significant spanwise viscous dissipation heating effect on the dissociation rate the net sweep effect diminishes the gas-phase reaction effect to zero beyond Λ ≃ 60 deg, analogously to the surface reaction case.
Turbularization of an acoustic boundary layer on a transpiring surface

Turbularization of an acoustic boundary layer (Stokes layer) on impermeable and permeable surfaces is analytically considered. The theoretical approach utilizes a second-order closure model of turbulence. Both an approximate, closed-form solution and a more comprehensive finite-difference solution of the time-dependent, parabolic, one-dimensional governing equations are obtained. For simple acoustic boundary layers on impermeable surfaces, both the approximate solution and the numerical results for the critical acoustic Mach number required for turbulent transition are qualitatively confirmed by experiment. The calculations for acoustic boundary layers with transpiration (injection) indicate a substantial reduction of the acoustic Mach number required for transition, up to a limiting injection velocity that is frequency dependent. The results may provide a mechanism for flow-related combustion instability in practical systems, particularly solid propellant rockets, since turbularization of the near-surface combustion zone could result at relatively low-acoustic Mach numbers.
Analysis of Cracked Gas Turbine Blades

Results from an analysis of cracked first stage blades (or buckets) from two General Electric Frame 7001 E industrial/electric utility gas turbines are presented. Numerous cracks were observed along the leading-edge and mid-chord regions of the pressure and suction surfaces. In one unit cracks were found after 874 start-stop cycles, which included 218 trips from load and 11,000 service hours. Buckets in the sister engine were examined after 1800 cycles, which included 218 trips from load and 24,000 service hours. In both cases, cracks initiated in the platinum aluminide coating and propagated into the IN-738LC base metal. For the 11,000-hour bucket, 20-mil (0.5-mm) deep cracks were observed, and for the 24,000-hour bucket, the leading edge cracks had grown to the leading edge cooling hole, a distance of 0.2 inches (5 mm). The number of cycles to crack initiation was in good agreement with thermal mechanical fatigue (TMF) predictions from the REMLIF computer program, which is part of the Electric Power Research Institute's (EPRI) Life Management System. The cracking was greatly accelerated by the large number of trips experienced. The extensive crack propagation that occurred is thought to have been strongly assisted by oxygen and sulfur penetration along the grain boundaries. The coating on the leading edge degraded from the original platinum-aluminide plus beta phases to a gamma prime phase after 24,000 hours of service, but it was still protective except where it was cracked. Where the coating was cracked, environmental attack of the interdiffusion zone and base metal occurred, resulting in spallation of the coating and preferential grain boundary attack. Operating and maintenance considerations for optimizing bucket life in demanding cyclic duty environments are also discussed.
Changes in women's hours of market work: The role of returns to experience

Abstract Over the past several decades, married women's hours of market work increased significantly in the US. I argue that changes in behavior by married women with children account for much of this change. In particular, the pattern of married women's work hours has changed substantially over the life cycle. In the past, married women in childbearing age tended to specialize in childrearing and home production activities at the expense of engaging in market work. Now they do not curb the hours they work in the market. What factors contribute to this change in behavior? In this paper, I focus on relative changes in returns to experience as an explanation. I use PSID data for the 1970s and the 1990s to estimate the extent to which relative returns to experience have changed. I then use a life-cycle model with human capital accumulation and home production to quantitatively assess the consequences of this increase for married women's hours of work over the life cycle. The estimates of the human capital production function show that women's marginal returns to experience increased by 25% across decades, whereas men's increased by only 6%. I show that this relative change accounts for 96% of the observed variation in married women's hours of work. Moreover, according to the model, the increase in returns to experience accounts for roughly half of the increase in the female/male wage ratio that is found in the data. I also show that a decline in the gender wage gap, holding returns to experience constant, accounts for only 18% of the total increase in hours of work. As a consequence, it cannot explain the change in the shape of women's life-cycle profiles. Although the focus of the analysis is the labor supply behavior of women, the model also allows predictions about the behavior of men and single women. These predictions are consistent with the data.
2-Diazoacetoacetic acid, an efficient and convenient reagent for the synthesis of α-diazo-β-ketoesters

The formation of various α-diazo acetoacetic esters can be obtained in a single transformation with good to excellent yields using readily available 2-diazoacetoacetic acid.