cssi/SciSciGPT-SciSciNet huggingface dataset:
Radiation Effects In Semiconductor Laser Diode Arrays

The effects of radiation events are important for many of the present and future applications that involve opto-electronic components. Laser diodes show a strong resistance to degradation by gamma rays, prompt x-rays and (to a lesser extent), neutrons. This is due to the short carrier lifetime that is associated with stimulated emission and the high current injection conditions that are present in these devices. Radiation-resistant properties should carry over to many of the more recently developed devices such as multi-stripe array and broad area laser diodes. There are however, additional considerations for radiation tolerance that are introduced by these devices. Arrays and other high power laser diodes have larger active region volumes than lower power single stripe devices. In addition, evanescent field coupling between stripes, the material quality available from newer MOCVD expitaxial growth techniques, and stripe definition methods may all influence the radiation tolerance of the high power laser diode devices. Radiation tests have been conducted on various GaAs-GaAlAs laser diode array and broad area devices. Tests involving total gamma dose have indicated that high power laser diodes and arrays have small degradations in light power output with current input after 4 MRad(Si) of radiation from a Co60 source. Additional test results involving flash X-rays indicate that high power diode lasers and arrays are tolerant to 10rads(Si)/sec, when observed on microsecond or milli-second time scales. High power diode laser devices were also irradiated with neutrons to a fluence of 1014 neutrons per cm2 with some degradation of thresh-old current level.
Nucleation Theory: is Replacement Free Energy Needed?

The classical nucleation equation of Volmer can be derived from fluctuation theory, Gibbs’ result for the work to form a critical nucleus, and the rate of collision with vapor molecules with the critical nucleus, without using the “capillarity approximation”. However, this “approximation” can be derived from thermodynamic equations. Corrections to Volmer’s equation are based on questionable assumptions of equilibrium.
On Prime Ideals of Noetherian Skew Power Series Rings

We study prime ideals in skew power series rings T:= R[[y; τ, δ]], for suitably conditioned complete right Noetherian rings R, automorphisms τ of R, and τ-derivations δ of R. Such rings were introduced by Venjakob, motivated by issues in noncommutative Iwasawa theory. Our main results concern “Cutting Down” and “Lying Over.” In particular, assuming that τ extends to a compatible automorphsim of T, we prove: If I is an ideal of R, then there exists a τ-prime ideal P of T contracting to I if and only if I is a τ-δ-prime ideal of R. Consequently, under the more specialized assumption that δ = τ − id (a basic feature of the Iwasawa-theoretic context), we can conclude: If I is an ideal of R, then there exists a prime ideal P of T contracting to I if and only if I is a τ-prime ideal of R. Our approach depends essentially on two key ingredients: First, the algebras considered are Zariskian (in the sense of Li and Van Oystaeyen), and so the ideals are all topologically closed. Second, topological arguments can be used to apply previous results of Goodearl and the author on skew polynomial rings.
Classification of residential exposure to nitrogen dioxide

Abstract In epidemiological studies of indoor nitrogen dioxide (NO 2 ) reported to date, only a limited number of measurements were made to estimate personal exposures. The accuracy of exposure estimates depends on the measurement error inherent in the samplers and in the sampling scheme. If categorical measures of exposure are used, the consequences of measurement error vary with classification rules. The effects of alternative measurement strategies on exposure classification were evaluated using NO 2 diffusion sampler measurements from 653 residences with gas cooking ranges. A time-series of consecutive 2-week integrated measurements was obtained for each home. During the winter season, the standard deviation was 26% of the mean. The probability of misclassification, a function of the mean and the standard deviation per home, was examined for three concentration classes (
New institutional accounting and IFRS

This paper reviews recent advances from the institutional economics and accounting literature to help build a nascent framework for ‘new institutional accounting’ (NIA) research. The framework has five basic elements: (i) institutional structure (formal vs. informal); (ii) level of analysis (macro institutions vs. micro organisations); (iii) causation (exogenous vs. endogenous institutions); (iv) interdependencies (complementarities); and (v) efficient vs. inefficient outcomes. I apply the framework to help provide insights into the determinants and outcomes of accounting institutions (including IFRS) and non-accounting institutions observed around the world. I conclude with a discussion of opportunities and directions for future research on ‘new institutional accounting’.
Radiodetection of Neutrinos

Abstract Despite 100 years of effort, we still know very little about the origin of ultra-high energy cosmic rays. The observation of neutrinos produced when cosmic-ray protons with energies above 4 × 10 19 eV interact with the cosmic microwave background radiation, or in the neutrino sources, would tell us much about the origin and composition of these particles. Over the past decade, many experiments have searched for radio waves emitted from the charged particle showers produced when Extremely High Energy (EHE) neutrinos interact with Antarctic or Greenland ice or the moon. These experiments have not yet observed a neutrino signal. Two groups are now proposing to instrument 100 km 3 of Antarctic ice with radio antennas, producing a detector large enough to observe a clear EHE neutrino signal in a few years of operation.
The Youthful Appearance of the 2003 EL61 Collisional Family

We present new solar phase curve observations of the 2003 EL61 collisional family showing that all the members have light-scattering properties similar to the bright icy satellites of the giant planets and dwarf planets. Compared with other Kuiper Belt objects (KBOs), the five family members we observe (2003 EL61, 2002 TX300, 2003 OP32, 2005 RR43, and 1995 SM55) have conspicuously neutral color (V – I = 0.6-0.8 mag) and flat phase curves at small phase angles (phase coefficients of 0.0-0.1 mag deg–1). Comparing the phase curves we observe for other icy KBOs with the phase curves of icy satellites, we find that the flat phase curves of the 2003 EL61 family are an indication that they have high albedo surfaces coated with fresh ice in the last ~100 Myr. We examine possible resurfacing processes and find none that are plausible. To avoid the influence of cosmic radiation that darkens and reddens most icy surfaces on times scales 100 Myr, the family members must be unusually depleted in carbon, or the collision that created the family occurred so recently that the parent body and fragments have not had time to darken. We also find a rotation period of 4.854 (±0.003) h with amplitude 0.26 (±0.04) mag for 2003 OP32.
Asymptomatic hyperuricemia. Risks and consequences in the Normative Aging Study.

Abstract To quantify the consequences of asymptomatic hyperuricemia, this study examined rates for a first episode of gouty arthritis based on 30,147 human-years of prospective observation. A cohort of 2,046 initially healthy men in the Normative Aging Study was followed for 14.9 years with serial examinations and measurement of urate levels. With prior serum urate levels of 9 mg/dl or more, the annual incidence rate of gouty arthritis was 4.9 percent, compared with 0.5 percent for urate levels of 7.0 to 8.9 mg/dl and 0.1 percent for urate levels below 7.0 mg/dl. With urate levels of 9 mg/dl or higher, cumulative incidence of gouty arthritis reached 22 percent after five years. Incidence rates were three times higher for hypertensive patients than for normotensive patients (p
Pattern formation in weakly damped parametric surface waves driven by two frequency components

A quasi-potential approximation to the Navier–Stokes equation for low-viscosity fluids is developed to study pattern formation in parametric surface waves driven by a force that has two frequency components. A bicritical line separating regions of instability to either of the driving frequencies is explicitly obtained, and compared with experiments involving a frequency ratio of 1/2. The procedure for deriving standing wave amplitude equations valid near onset is outlined for an arbitrary frequency ratio following a multiscale asymptotic expansion of the quasi-potential equations. Explicit results are presented for subharmonic response to a driving force of frequency ratio 1/2, and used to study pattern selection. Even though quadratic terms are prohibited in this case, hexagonal or triangular patterns are found to be stable in a relatively large parameter region, in qualitative agreement with experimental results.
High-power microwave bandwidth broadening by air breakdown

Wideband, high-power microwave pulses are expected to have important applications in the future. One of these applications is ultra-wideband radar. The wide bandwidth should generate increased information for targetcharacterization and identification. The high power should result in increased target detection range for conventional targets and targets with reduced signatures. A way to generate wideband, high-power microwave pulses with relatively conventional technology is to tail erode high-power pulses by passage through a low-pressure air cell. In this process, the tails ofshort(3 — 10 ns), high-amplitude (<1 MV/rn) pulses are removed. This erosion shortens thepulses and generates transmitted pulses with broadenedbandwidths. Thepressure mustbe matched to several incident pulse characteristics to create enough electron density to cause strong tail erosion. The important pulse characteristics are amplitude, frequency, pulse length, and pulse shape. Tail erosion of microwave pulses in the earth's atmosphere has previously been examined with one-dimensional, finite difference computer calculations.13 Experiments on tail erosion in a rectangular waveguide have verified two-dimensional (2D), finite difference computer calculations.4'5 We have shown experimentally that tail erosion from air breakdown broadens the 3 dB bandwidths of 2.8608 GHz incident pulses in a rectangular waveguide at 3.5 ton. The incident pulse amplitude varied from 0.67 —1.16 MV/rn. The pulse bandwidth increased from 0. 147 GHz by 0.0097 — 0.039 GHz or 0.34 — 1.4% relative. The incident bandwidth was 5. 12% relative to the incident carrierfrequency. This experimentalbroadening was simulated with a2D, electromagnetic, electron fluid computercode foravalanche ionization. The simulation predicted bandwidth broadening by 0.029 —0.13 GHz or 1.0 —4.4% relative for a peak initial electron density of 10 electrons/cm3. Although the measured and calculated transmitted electric field envelopes were in close agreement, the calculated bandwidths exceeded those measured by 13 —47%. Because the detectors were not fast enough to resolve individual cycles and therefore determine thelocalfrequency across thepulses, wepresently conclude that the simulation gives betterestimates of reality than do the measurements. The computer code gives predictions of the bandwidth broadening of 3.5 ns incident pulses at 3.5 torr for a Gaussian spatial background electron distribution with a 3 cm fullwidth at halfmaximum (FWHM)in the axialdirection. The peak valueofthe electron density distribution and its transverse FWHM are variable. Incident amplitudes of 1 —18 MV/rn and peak electron densities of 10 — 1011 electrons/cm3 are considered. The transmittedbandwidth varies from 0.352— 3.21 GHz or 12.3 —112% relative. The transmitted spectralcenter frequency varies from 2.87 —4.72 GHz. The transmitted amplitude at 54.6 cm from the input to thelow-pressure section varies from 0.263 — 12.7 MV/rn on the waveguide center line.
The Age, Extinction, and Distance of the Old, Metal-rich Open Cluster NGC 6791

An extensive grid of metal-rich isochrones utilizing the latest available input physics has been calculated for comparison with the old, metal-rich open cluster NGC 6791. The isochrones have been simultaneously fitted to BV and VI color-magnitude diagrams, with the same composition, reddening, and distance modulus required for both colors. Our best-fitting isochrone assumes [Fe/H] = +0.4, scaled solar abundance ratios, and ΔY/ΔZ = 2 (Y = 0.31), yielding an excellent fit to the data at all points along the major sequences. The resulting age is 8 Gyr, with E(B-V) = 0.10 and (m-M)V = 13.42. The derived cluster parameters are fairly robust to variations in the isochrone [Fe/H] and helium abundances. All the acceptable fits indicate that 0.08 ≤ E(B-V) ≤ 0.13 and 13.30 ≤ (m - M)V ≤ 13.45 and that NGC 6791 has an age of 8.0 ± 0.5 Gyr. The fits also suggest that ΔY/ΔZ lies between 1 and 3. A metallicity as low as solar is clearly ruled out, as is ΔY/ΔZ = 0. Comparison with previous isochrone studies indicates that the derived reddening is primarily due to our use of the most recent color transformations, whereas the age depends on both the colors and the input physics. Our isochrones provide an excellent fit to the Hyades zero-age main sequence as determined by Hipparcos, providing evidence that our derived reddening and distance modulus are reliable.
Kinetics of Cl(2P) reactions with CF3CHCl2, CF3CHFCl, and CH3CFCl2

The rate coefficients for the removal of Cl atoms by reaction with three HCFCs, CF3CHCl2 (HCFC-123), CF3CHFCl (HCFC-124), and CH3CFCl2 (HCFC 141b), were measured as a function of temperature between 276 and 397 K. CH3CF2Cl (HCFC-142b) was studied only at 298 K. The Arrhenius expressions obtained are: k1 = (3.94 ± 0.84)× 10−12 exp[−(1740 ± 100)/T] cm3 molecule−1 s−1 for CF3CHCl2 (HCFC 123); k2 = (1.16 ± 0.41) × 10−12 exp[−(1800 ± 150)/T] cm3 molecule−1 s−1 for CF3CHFCl (HCFC 124); and k3 = (1.6 ± 1.1) × 10−12 exp[−(1800 ± 500)/T] cm3 molecule−1 s−1 for CH3CFCl2 (HCFC 141b). In case of HCFC 141b, non-Arrhenius behavior was observed at temperatures above ca. 350 K and is attributed to the thermal decomposition of CH2CFCl2 product into Cl + CH2CFCl. In case of HCFC-142b, only an upper limit for the 298 K value of the rate coefficient was obtained. The atmospheric significance of these results are discussed. © 1993 John Wiley & Sons, Inc.
Two applications of pressure tuning spectroscopy to processes in liquids

Abstract In this short review, we describe two problems involving pressure tuning spectroscopy. The first of these concerns reversible pressure induced changes in conformation of the protein lysozyme with consequent changes in its affinity for N -acetyl-D glucosamine. The second problem involves the effect of solvent viscosity on the rate of isomerization of 4, N , N ′-dimethylaminobenzonitrile (DMABN) in a series of linear alcohols, isobutanol and glycerol. An important result of this study is that there can be apparent differences in resistance to shear near a solute molecule for solvents with the same bulk viscosity but different geometries. This concept may be extended to other bulk properties like density, compressibility and dielectric constant.
The incompleteness of Misra and Chandy's proof systems

Abstract In this paper we show that Misra and Chandy's proof systems for networks of communicating processes (1981, 1982) are incomplete.
Design of high voltage 4H-SiC superjunction Schottky rectifiers

This paper presents a novel Schottky rectifier structure based on the superjunction approach, which is utilizes 2- and 3D field shaping to increase the avalanche breakdown voltage. Device forward and blocking characteristics are analyzed with numerical simulations and compared with conventional 4H-SiC Schottky rectifiers. Optimal design tradeoffs between breakdown voltage and specific on-resistance are obtained for high voltage 4H-SiC superjunction Schottky rectifiers. The results show that the new structure can provide a 20 /spl times/ lower R/sub on,sp/ than conventional Schottky rectifier for 6kV device. In addition, device termination and possible fabrication steps for the superjunction devices are also presented.
Does Solar Structure Vary with Solar Magnetic Activity

We present evidence that solar structure changes with changes in solar activity. We find that the adiabatic index, Γ1, changes near the second helium ionization, i.e., at a depth of about 0.98 R☉. We believe that this change is a result of the change in the effective equation of state caused by magnetic fields. Inversions should be able to detect the changes in Γ1 if mode sets with reliable and precise high-degree modes are available.
Common divisors of elliptic divisibility sequences over function fields

Let E/k(T) be an elliptic curve defined over a rational function field of characteristic zero. Fix a Weierstrass equation for E. For points R ∈ E(k(T)), write xR=AR/DR2 with relatively prime polynomials AR(T),DR(T) ∈ k[T]. The sequence {DnR}n≥ 1 is called the elliptic divisibility sequence of R. Let P,Q ∈ E(k(T)) be independent points. We conjecture that deg (gcd(DnP, DmQ)) is bounded for m, n ≥ 1, and that gcd(DnP, DnQ) = gcdDP, DQ) for infinitely many n ≥ 1. We prove these conjectures in the case that j(E) ∈ k. More generally, we prove analogous statements with k(T) replaced by the function field of any curve and with P and Q allowed to lie on different elliptic curves. If instead k is a finite field of characteristic p and again assuming that j(E) ∈ k, we show that deg (gcd(DnP, DnQ)) is as large as Open image in new window for infinitely many n≢0 (mod p).
Beyond Moran's I: Testing for Spatial Dependence Based on the Spatial Autoregressive Model

The statistic known as Moran's I is widely used to test for the presence of spatial dependence in observations taken on a lattice. Under the null hypothesis that the data are independent and identically distributed normal random variates, the distribution of Moran's I is known, and hypothesis tests based on this statistic have been shown in the literature to have various optimality properties. Given its simplicity, Moran's I is also frequently used outside of the formal hypothesis-testing setting in exploratory analyses of spatially referenced data; however, its limitations are not very well understood. To illustrate these limitations, we show that, for data generated according to the spatial autoregressive (SAR) model, Moran's I is only a good estimator of the SAR model's spatial-dependence parameter when the parameter is close to 0. In this research, we develop an alternative closed-form measure of spatial autocorrelation, which we call APLE, because it is an approximate profile-likelihood estimator (APLE) of the SAR model's spatial-dependence parameter. We show that APLE can be used as a test statistic for, and an estimator of, the strength of spatial autocorrelation. We include both theoretical and simulation-based motivations (including comparison with the maximum-likelihood estimator), for using APLE as an estimator. In conjunction, we propose the APLE scatterplot, an exploratory graphical tool that is analogous to the Moran scatterplot, and we demonstrate that the APLE scatterplot is a better visual tool for assessing the strength of spatial autocorrelation in the data than the Moran scatterplot. In addition, Monte Carlo tests based on both APLE and Moran's I are introduced and compared. Finally, we include an analysis of the well-known Mercer and Hall wheat-yield data to illustrate the difference between APLE and Moran's I when they are used in exploratory spatial data analysis.
Tangents and Rectifiability of Ahlfors Regular Lipschitz Differentiability Spaces

We study Lipschitz differentiability spaces, a class of metric measure spaces introduced by Cheeger in [Ch99]. We show that if an Ahlfors regular Lipschitz differentiability space has charts of maximal dimension, then, at almost every point, all its tangents are uniformly rectifiable. In particular, at almost every point, such a space admits a tangent that is isometric to a finite-dimensional Banach space. In contrast, we also show that if an Ahlfors regular Lipschitz differentiability space has charts of non-maximal dimension, then these charts are strongly unrectifiable in the sense of Ambrosio-Kirchheim.
X-RAY MICROLENSING IN RXJ1131-1231 AND HE1104-1805

We present results from a monitoring campaign performed with the Chandra X-ray Observatory of the gravitationally lensed quasars RX J1131–1231 and HE 1104–1805. We detect significant X-ray variability in all images of both quasars. The flux variability detected in image A of RX J1131–1231 is of particular interest because of its high amplitude (a factor of ~ 20). We interpret it as arising from microlensing since the variability is uncorrelated with that of the other images and the X-ray flux ratios show larger changes than the optical as we would expect for microlensing of the more compact X-ray emission regions. The differences between the X-ray and optical flux ratios of HE 1104–1805 are less dramatic, but there is no significant soft X-ray or dust absorption, implying the presence of X-ray microlensing in this system as well. Combining the X-ray data with the optical light curves we find that the X-ray emitting region of HE 1104–1805 is compact with a half-light radius 6rg , where the gravitational radius is r g = 3.6 × 1014 cm, thus placing significant constraints on AGN corona models. We also find that the microlensing in HE 1104–1805 favors mass models for the lens galaxy that are dominated by dark matter. Finally, we better characterize the massive foreground cluster near RX J1131–1231, set limits on other sources of extended X-ray emission, and limit the fluxes of any central odd images to be 30-50 (3σ) times fainter than the observed images.
Biology of the 2Na+/1H+ antiporter in invertebrates.

The functional expression of membrane transport proteins that are responsible for exchanging sodium and protons is a ubiquitous phenomenon. Among vertebrates the Na+/H+ antiporter occurs in plasma membranes of polarized epithelial cells and non-polarized cells such as red blood cells, muscle cells, and neurons, and in each cell type the transporter exchanges one sodium for one hydrogen ion, is inhibited by amiloride, and regulates intracellular pH and sodium concentration within tight limitations. In polarized epithelial cells this transporter occurs in two isoforms, each of which is restricted to either the brush border or basolateral cell membrane, and perform somewhat different tasks in the two locations. In prokaryotic cells, sodium/proton exchange occurs by an electrogenic 1Na+/2H+ antiporter that is coupled to a primary active proton pump and together these two proteins are capable of tightly regulating the intracellular concentrations of these cations in cells that may occur in environments of 4 M NaCl or pH 10-12. Invertebrate epithelial cells from the gills, gut, and kidney also exhibit electrogenic sodium/proton exchange, but in this instance the transport stoichiometry is 2Na+/1H+. As with vertebrate electroneutral Na+/H+ exchange, the invertebrate transporter is inhibited by amiloride, but because of the occurrence of two external monovalent cation binding sites, divalent cations are able to replace external sodium and also be transported by this system. As a result, both calcium and divalent heavy metals, such as zinc and cadmium, are transported across epithelial brush border membranes in these animals and subsequently undergo a variety of biological activities once accumulated within these cells. Absorbed epithelial calcium in the crustacean hepatopancreas may participate in organismic calcium balance during the molt cycle and accumulated heavy metals may undergo complexation reactions with intracellular anions as a detoxification mechanism. Therefore, while the basic process of sodium/proton exchange may occur in invertebrate cells, the presence of the electrogenic 2Na+/1H+ antiporter in these cells allows them to perform a wide array of functions without the need to develop and express additional specialized transport proteins. J. Exp. Zool. 289:232-244, 2001.
Viscosity pressure correlation of liquids

A single correlation was obtained to predict Newtonian viscosity-pressure coefficients of mineral oils, resin and polymer blends, pure hydrocarbons, and nonhydrocarbons. The correlation has been tested for a temperature range from 0°c (32 °F) to 135°C (275 °F). The empirical correlation makes use of atmospheric viscosity and density at the temperature of interest and viscosity-temperature property (mo) of the fluids. When the correlation was compared with other leading correlations, it was shown to require less physical-property data, apply to n wider range of chemical compositions, cover a wider range in fluidity, and provide greater accuracy. The correlation is presented in the form of a polynominal equation. Presented at the 34th Annual Meeting in St. Louis, Missouri, April 30-May 3, 1979
Capacity gain from transmitter and receiver cooperation

Capacity gain from transmitter and receiver cooperation are compared in a relay network where the cooperating nodes are close together. When all nodes have equal average transmit power along with full channel state information (CSI), it is proved that transmitter cooperation outperforms receiver cooperation, whereas the opposite is true when power is optimally allocated among the nodes but only receiver phase CSI is available. In addition, when the nodes have equal average power with receiver phase CSI only, cooperation is shown to offer no capacity improvement over a non-cooperative scheme with the same average network power. When the system is under optimal power allocation with full CSI, the decode-and-forward transmitter cooperation rate is close to its cut-set capacity upper bound, and outperforms compress-and-forward receiver cooperation. Moreover, it is shown that full CSI is essential in transmitter cooperation, while optimal power allocation is essential in receiver cooperation
TeV gamma-ray astronomy

Abstract The observational status of gamma-ray astronomy in the TeV energy range is rapidly changing and is reviewed (1987) with emphasis on the limitations of the present observations. It is apparent that gamma-ray detection techniques must be improved and some methods by which this can be achieved are outlined. There are now more than a dozen TeV gamma-ray telescopes in operation or planned; three of these are in the USA. Ultimately the flux sensitivity that must be achieved in this field will require a telescope so large that it must be part of a national or international facility.
GRAVITATIONAL WAVE RECOIL AND THE RETENTION OF INTERMEDIATE-MASS BLACK HOLES

Duringtheinspiralandmergerofabinaryblackhole,gravitationalradiationisemittedanisotropicallyduetoasymmetries inthe merger configuration.This anisotropic radiation leads toagravitational wave kick,or recoil velocity,as large as � 4000 km s � 1 . We investigate the effect gravitational recoil has on the retention of intermediate-mass black holes(IMBHs)withinthepopulationofGalacticglobularclustersbysimulatingtheresponseof IMBHstoblackhole mergers. Assuming that our current understanding of IMBH formation is correct and yields an IMBH seed in every globular cluster, we find asignificantproblem inretaining low-mass IMBHs(P1000M� ) in the typical merger-rich globularclusterenvironment.Givenauniformblackholespindistributionandorientationandastellar-massblackhole mass function generated in a low-metallicity system, we find that only three of the Milky Way globular clusters can retainanIMBHwithaninitialmassof 200M� .Evenif IMBHshaveaninitialmassof 1000M� ,only60wouldremain withinMilkyWayglobularclusters,andeachwouldresideonlyinthemostmassiveclusters.Ourcalculationsshowthat
Intramolecular cyclopropanation using iodonium ylides. The 3,5-cyclovitamin D ring A synthon

Abstract The key intermediate 2b for 3,5-cyclovitamin D ring A synthon 13 was prepared in 80% yield as a diastereomeric mixture (70:30) via intramolecular cyclopropanation from iodonium ylide 10b.
On statistical analysis of a sample from a population of unknown species

Abstract A population consisting of an unknown number, ν, of distinct species is sampled by selecting one member of the population at a time. Estimation of ν and the probability of discovering a new species in an additional selection have been discussed by several authors. By defining the sample space appropriately, we obtain complete sufficient statistics and show that some inferences can be derived using standard methods. In particular, we prove Starr's (1979) conjecture by showing that his estimator is a function of complete sufficient statistics, and present the best unbiased estimators of a more general class of parametric functions. Some properties of these estimators are obtained using the theory of U-statistics. We also consider the case where k ( k ≥1) members of the population are selected at each stage and derive the best unbiased estimator of the expected number of new species observed in an additional stage of selection.
Photoacoustic insights on diesel exhaust particles

Photoacoustic measurements at General Motors Research Laboratories on diesel exhaust particulate emissions are reviewed. Conventional optical techniques provide real-time qualitative monitoring of particle mass concentration, but typical data exhibit considerable scatter, suggesting that the assumption of a simple correlation between optical response and particle mass concentration is unsound. Photoacoustic measurements at long wavelengths not only provide excellent sensitivity but, in principle, also avoid problems associated with variations in particular size. However, variations in shape (via clustering) and particle chemistry, resulting from varying engine operating conditions, can drastically affect the optical attenuation per unit particle mass, particularly for very small particles.
Eleven Euclidean Distances are Enough

Abstract The well-known three-distance theorem states that there are at most three distinct gaps between consecutive elements in the set of fractional parts of the first n multiples of any real number. We generalise this theorem to higher dimensions under a suitable formulation. The three-distance theorem can be thought of as a statement about champions in a tournament. The players in the tournament are geodesics between pairs of multiples of the given real number (modulo 1), two edges play each other if and only if they overlap, and an edge loses only against edges of shorter length that it plays against. According to the three-distance theorem, there are at most three distinct values for the lengths of undefeated edges. In the plane and in higher dimensions, we consider fractional parts of multiples of a vector of real numbers, and two edges play if their projections along any axis overlap. In the plane, there are at most 11 values for the lengths of undefeated edges.
Exploring the mental space of autonomous intentional agents

The ability to infer the intentions of other agents on the basis of their motion is a critical psychological faculty. In the present study, we examine a key question underlying this process, namely: What are the psychologically natural categories of intentional agents and actions? To investigate this question empirically, we use displays containing a number of autonomous, independently programmed agents moving about a two-dimensional environment and interacting with one another. Each agent behaves according to its own simple program, controlled by a small number of parameters that define its "personality." We probe participants' impressions of the similarities among the behaviors of the various agents, and then use multidimensional scaling in an attempt to recover the subjective mental space of agent types. An important variable underlying this space turns out to be a parameter that determines how the agent reacts to a nearby agent at one critical distance. A follow-up experiment suggests that variation along this parameter ultimately contributes to modulating a more fundamental perceptual dimension that reflects how "hostile" or "friendly" the agents appear to be.
Factorization in non-leptonic decays of heavy mesons

We propose a QCD-based model for calculation of the non-perturbative corrections to the factorization approximation in the decays of heavy mesons. In the framework of the model, factorization in pseudoscalar transitions holds exactly at the leading order leaving the opportunity to calculate non-leading corrections consistently.
CONFLICT DATASETS: A PRIMER FOR ACADEMICS, POLICYMAKERS, AND PRACTITIONERS

Prominent conflict datasets used in the social scientific study of war and peace are summarized. These include datasets for armed conflicts (e.g., COW and UCDP/PRIO wars and sub‐war conflicts), terrorism (e.g., GTD and ITERATE terrorist incidents), and events (e.g., WEIS, KEDS, and VRA cooperative and conflict actions). Topics explored include the diversity of conflict types, alternative definitions of war and sub‐war conflict, historical patterns of violence in the international system, and degree of overlap across datasets.
Insights into the mechanism of the β-elimination catalyzed by the N-terminal domain of DNA polymerase β

Abstract The N-terminal domain of DNA polymerase β carries an activity for excision of deoxyribose 5-phosphate from DNA at an interaction interface that includes a helix-hairpin-helix motif containing Lys-68 and Lys-72 and an adjacent Ω loop containing His-34 and Lys-35. His-34 displays a low pK a (5.7) due to proximity to Lys-35. In a proposed mechanism, Lys-68 protonates the hemiacetal O4′ and His-34 stabilizes the protonated aldehyde-type species, possibly accepting the proton. In one of two possible mechanisms, Lys-68 or Lys-72 forms a Schiff's base with the substrate. His-34 can function in C2′ deprotonation for the Lys-68 Schiff's base intermediate, while the proton would be transferred to water for the Lys-72 Schiff's base. Lys-35 stabilizes the phosphomonoester leaving group in either case.
Short horizons, time inconsistency, and optimal social security

We study the optimal provision of social security in a dynamically efficient economy using a continuous-time overlapping-generations model in which consumers have short planning horizons. The short-horizon mechanism leads to dynamic optimization that is time-inconsistent over the life cycle. Our calibrated general-equilibrium results are generally supportive of social security for a wide array of social welfare functions. Thus, the basic life-cycle model can be augmented with only this slight twist in order to rationalize a social security program with the current U.S. tax rate.
Chiral effective lagrangian description of bulk nuclear matter

Abstract Here we point out that the four-nucleon terms incorporate into lowest order non-linear chiral effective Lagrangians the same description of bulk nuclear matter contained in the Walecka model, that is generally considered satisfactory. We find this point worth noticing because, while the Walecka model is an entirely phenomenological renormalizable model, non-linear chiral Lagrangians have a deep basis in elementary particle physics, and, in this sense, are more fundamental.
New efficient method for the synthesis of the antiviral agent carbovir

Abstract An efficient synthesis of (±)-carbovir 1 and simple des(hydroxymethyl) analogues, e.g., 5 , is reported which uses a new approach for attaching nucleoside bases to cycloalkene systems.
A Bayesian estimation of macro and micro CES production functions

Abstract The paper presents a Bayesian estimation of CES production functions. The proposed estimation method is easier to use than methods so far developed and it allows a direct comparison with the maximum likelihood estimator. A Bayesian highest posterior density interval inference is made to examine the validity of the Cobb–Douglas representation. The method is applied to Japanese macro data and to micro data on two Japanese manufacturing plants. The results indicate that the current practice of employing the Cobb–Douglas form a priori ought to be corrected. In addition, the micro data present results paradoxical to the commonly held view of capital intensity.
The diastereoselective epoxidation of olefins in supercritical carbon dioxide

Allylic alcohols are epoxidized with tert-butyl hydroperoxide in the presence of a vanadyl salen oxo-transfer catalyst in supercritical CO2. The metal catalyst was prepared in a simple two step, Schiff base reaction to form the salen ligand, followed by complexation to the vanadyl group. The epoxidation reactions are clean and give both high yields and good diastereoselectivity.
Component-Mode-Based Reduced Order Modeling Techniques for Mistuned Bladed Disks—Part II: Application

In this paper the component-mode-based methods formulated in the companion paper (Part I: Theoretical Models) are applied to the dynamic analysis of two example finite element models of bladed disks. Free and forced responses for both tuned and mistuned rotors are considered. Comprehensive comparisons are made among the techniques using full system finite element solutions as a benchmark. The accurate capture of eigenfrequency veering regions is of critical importance for obtaining high-fidelity predictions of the rotor's sensitivity to mistuning. Therefore, particular attention is devoted to this subject. It is shown that the Craig-Bampton component mode synthesis (CMS) technique is robust and yields highly reliable results. However, this is achieved at considerable computational cost due to the retained component interface degrees of freedom. It is demonstrated that this problem is alleviated by a secondary modal analysis reduction technique (SMART). In addition, a non-CMS mistuning projection method is considered. Although this method is elegant and accurate, it is seen that it lacks the versatility and efficiency of the CMS-based SMART. Overall, this work shows that significant improvements on the accuracy and efficiency of current reduced order modeling methods are possible.
Representation Theory of the Nonstandard Hecke Algebra

The nonstandard Hecke algebra $\check {\mathcal {H}}_{r}$ was defined by Mulmuley and Sohoni to study the Kronecker problem. We study a quotient $\check {\mathcal {H}}_{r,2}$ of $\check {\mathcal {H}}_{r}$ , called the nonstandard Temperley–Lieb algebra, which is a subalgebra of the symmetric square of the Temperley–Lieb algebra TL r . We give a complete description of its irreducible representations. We find that the restriction of an irreducible $\check {\mathcal {H}}_{r,2}$ -module to $\check {\mathcal {H}}_{r-1,2}$ is multiplicity-free, and as a consequence, any irreducible $\check {\mathcal {H}}_{r,2}$ -module has a seminormal basis that is unique up to a diagonal transformation.
Space Weather Outreach: An informal education perspective

Abstract Informal science education institutions, such as science centers, play an important role in science education. They serve millions of people, including students and teachers. Within the last decade, many have tried to improve the public’s understanding of science and scientific research through informal education projects. The recent success of several space weather-related missions and research programs and the launch of the International Heliophysical Year (IHY) research and education programs make this an ideal time to inform the public about the importance and relevance of space weather to our understanding of heliophysical science. Communication efforts associated with space weather both benefit and are compromised by analogies to terrestrial weather. This paper summarizes the benefits and challenges of the terrestrial weather analogy using two exhibit evaluation studies. The paper also describes three components of the Space Science Institute’s Space Weather Outreach Program – Space Weather Center Website, Educator Workshops, and Small Exhibits – and how they can help to achieve the education goals of IHY.
Predicting and testing continental vertical motion histories since the Paleozoic

Abstract Dynamic topography at the Earth's surface caused by mantle convection can affect a range of geophysical and geological observations including bathymetry, sea-level change, continental flooding, sedimentation and erosion. These observations provide important constraints on and test of mantle dynamic models. Based on global mantle convection models coupled with the surface plate motion history, we compute dynamic topography and its history for the last 400 Ma associated with Pangea assembly and breakup, with particular focus on cratonic regions. We propose that burial-unroofing histories of cratons inferred from thermochronology data can be used as a new diagnostic to test dynamic topography and mantle dynamic models. Our models show that there are currently two broad dynamic topography highs in the Pacific and Africa for the present-day Earth that are associated with the broad, warm structures (i.e., superplumes) in the deep mantle, consistent with previous proposals of dynamical support for the Pacific and African superswells. Our models reveal that Pangea assembly and breakup, by affecting subduction and mantle upwelling processes, have significant effects on continental vertical motions. Our models predict that the Slave craton in North America subsides before Pangea assembly at 330 Ma but uplifts significantly from 330 Ma to 240 Ma in response to pre-Pangea subduction and post-assembly mantle warming. The Kaapvaal craton of Africa is predicted to undergo uplift from ~180 Ma to 90 Ma after Pangea breakup, but its dynamic topography remains stable for the last 90 Ma. The predicted histories of elevation change for the Slave and Kaapvaal cratons compare well with the burial-unroofing histories inferred from thermochronology studies, thus supporting our dynamic models including the development of the African superplume mantle structure. The vertical motion histories for other cratons can provide further tests of and constraints on our mantle dynamic models.
Robust Optimal Policy in a Forward-Looking Model with Parameter and Shock Uncertainty

This paper characterizes a robust optimal policy rule in a simple forward-looking model, when the policymaker faces uncertainty about model parameters and shock processes. We show that the robust optimal policy rule is likely to involve a stronger response of the interest rate to fluctuations in inflation and the output gap than is the case in the absence of uncertainty. Thus parameter uncertainty alone does not necessarily justify a small response of monetary policy to perturbations. However, uncertainty may amplify the degree of ‘super-inertia’ required by optimal monetary policy. We finally discuss the sensitivity of the results to alternative assumptions. Copyright © 2007 John Wiley & Sons, Ltd.
Normal fault growth in analog models and on Mars

Abstract Normal faults observed in extensional clay models evolve by displacement (throw) accumulation and concomitant trace length increase, and by segment linkage. The first of these processes leads to an increase in the maximum throw to trace length ( D max / L ) ratio, whereas the second leads to a decrease in this ratio. With increasing extension individual faults evolve along stepwise tracks in D max / L parameter space, although at any given time a summary plot of D max versus L for the entire fault population will typically span one order of magnitude in D max / L ratio and two orders of magnitude in trace length, obscuring the stepwise nature of fault evolution and giving the impression of self-similar fault growth along a locus of constant D max / L ratio. In addition, the number of simple faults (faults with a single throw maximum) incorporated into a compound fault (a fault with multiple throw maxima) is strongly correlated with the fault’s trace length, indicating that trace length increase is dominated by linkage not throw accumulation. When analyzed for evidence of relict simple faults (expressed as throw maxima), normal faults observed on Mars exhibit similar characteristics to those developed in analog clay models. By analogy, we infer that Mars normal faults evolve in a similar fashion to faults in clay models.
Metnase promotes restart and repair of stalled and collapsed replication forks

Metnase is a human protein with methylase (SET) and nuclease domains that is widely expressed, especially in proliferating tissues. Metnase promotes non-homologous end-joining (NHEJ), and knockdown causes mild hypersensitivity to ionizing radiation. Metnase also promotes plasmid and viral DNA integration, and topoisomerase IIα (TopoIIα)-dependent chromosome decatenation. NHEJ factors have been implicated in the replication stress response, and TopoIIα has been proposed to relax positive supercoils in front of replication forks. Here we show that Metnase promotes cell proliferation, but it does not alter cell cycle distributions, or replication fork progression. However, Metnase knockdown sensitizes cells to replication stress and confers a marked defect in restart of stalled replication forks. Metnase promotes resolution of phosphorylated histone H2AX, a marker of DNA double-strand breaks at collapsed forks, and it co-immunoprecipitates with PCNA and RAD9, a member of the PCNA-like RAD9–HUS1–RAD1 intra-S checkpoint complex. Metnase also promotes TopoIIα-mediated relaxation of positively supercoiled DNA. Metnase is not required for RAD51 focus formation after replication stress, but Metnase knockdown cells show increased RAD51 foci in the presence or absence of replication stress. These results establish Metnase as a key factor that promotes restart of stalled replication forks, and implicate Metnase in the repair of collapsed forks.
Accelerated Life Testing (ALT) in Microelectronics and Photonics: Its Role, Attributes, Challenges, Pitfalls, and Interaction With Qualification Tests

Accelerated life tests (ALTs) are aimed at the revealing and understanding the physics of the expected or occurred failures, i.e. are able to detect the possible failure modes and mechanisms. Another objective of the ALTs is to accumulate representative failure statistics. Adequately designed, carefully conducted, and properly interpreted ALTs provide a consistent basis for obtaining the ultimate information of the reliability of a product - the predicted probability of failure after the given time of service. Such tests can dramatically facilitate the solution to the cost effectiveness and time-to-market problems. ALTs should play an important role in the evaluation, prediction and assurance of the reliability of microelectronics and optoelectronics devices and systems. In the majority of cases, ALTs should be conducted in addition to the qualification tests, which are required by the existing standards. There might be also situations, when ALTs can be (and, probably, should be) used as an effective substitution for such standards, or, at least, as the basis for the improvement of the existing qualification specifications. We describe different types (categories) of accelerated tests, with an emphasis on the role that ALTs should play in the development, design, qualification and manufacturing of microelectronics and photonics products. We discuss the challenges associated with the implementation and use of the ALTs, potential pitfalls (primarily those associated with possible shifts in the mechanisms and modes of failure), and the interaction of the ALTs with other types of accelerated tests. The role of the nondestructive evaluations is also briefly outlined. The case of a laser welded optoelectronic package assembly is used to illustrate the concepts addressed.