cssi/SciSciGPT-SciSciNet huggingface dataset:
Temperature Analysis of Current Crowded Effect in Power Transistors

Both uniform temperature distribution and crowded temperature distribution for a large-geometry power transistor are studied. Different concepts are used for calculating these two types of temperature distribution. In the first instance, in order to calculate the uniform temperature distribution, it is assumed that the power is uniformly dissipated over the entire emitter surface. In the second instance, in calculating the crowded temperature distribution, the power dissipation is assumed to be concentrated at the edges of the emitter. The time-dependent diffusion equation is solved to calculate the temperature rises in these two cases.
Solid Phase of Krypton on the Exterior of Individual Single-Walled Carbon Nanotubes

We have computed the adsorption of Krypton in a closed single-walled carbon nanotube using the method of Grand Canonical Monte Carlo. Our results indicate evidence of an incommensurate solid formed at high pressure and low temperature (T<85 K), before the formation of a second layer. The solid melts above that temperature. Our simulations are in good agreement with novel experimental results for adsorption in individual carbon nanotubes.
Default estimation, correlated defaults, and expert information

AbstractCapital allocation decisions are made on the basis of an assessment of creditwor-thiness. Default is a rare event for most segments of a bank’s portfolio and datainformation can be minimal. Inference about default rates is essential for ecientcapital allocation, for risk management and for compliance with the requirementsof the Basel II rules on capital standards for banks. Expert information is crucialin inference about defaults. A Bayesian approach is proposed and illustrated usingprior distributions assessed from industry experts. A maximum entropy approach isused to represent expert information. The binomial model, most common in appli-cations, is extended to allow correlated defaults yet remain consistent with Basel II.The application shows that probabilistic information can be elicited from expertsand econometric methods can be useful even when data information is sparse.Keywords: Bayesian inference, Basel II, risk management, prior elicitation,small probability estimation
{η6-1,4-(CH3SO3)2C6H4}Cr(CO)3: synthesis, characterization, and reactivity

Abstract Reaction of (MeCN)3Cr(CO)3 with hydroquinone in refluxing tetrahydrofuran (THF) produced {η6-1,4-C6H4(OH)2}Cr(CO)3 (1) which was subsequently converted to {η6-1,4-(CH3SO3)2C6H4}Cr(CO)3 (2) by treatment with methanesulfonyl chloride and triethylamine. A single-crystal X-ray study of 2 has been completed and is reported. Treatment of 2 with an oxygen nucleophile gave reaction at sulfur; whereas, treatment of 2 with lithium phenylacetylide resulted in decomposition of the complex to metallic chromium.
Mist/Steam Heat Transfer With Jet Impingement Onto a Concave Surface

Internal mist/steam blade cooling technology is proposed for the future generation of Advanced Turbine Systems (ATS). Fine water droplets about 5 μm were carried by steam through a slot jet onto a concave heated surface in a confined channel to simulate inner surface cooling at the leading edge of a turbine blade. Experiments covered Reynolds numbers from 7500 to 22,000 and heat fluxes from 3 to 21 kW/m 2 . The cooling is enhanced significantly near the stagnation point by the mist, decreasing downstream. Unlike impingement onto a flat target where the enhancement vanished at six jet diameters downstream, the cooling enhancement over a concave surface prevails at all points downstream. Similar to the results of the flat surface, the cooling enhancement declines at higher heat fluxes
The Neurocircuitry of Fear, Stress, and Anxiety Disorders

Anxiety disorders are a significant problem in the community, and recent neuroimaging research has focused on determining the brain circuits that underlie them. Research on the neurocircuitry of anxiety disorders has its roots in the study of fear circuits in animal models and the study of brain responses to emotional stimuli in healthy humans. We review this research, as well as neuroimaging studies of anxiety disorders. In general, these studies have reported relatively heightened amygdala activation in response to disorder-relevant stimuli in post-traumatic stress disorder, social phobia, and specific phobia. Activation in the insular cortex appears to be heightened in many of the anxiety disorders. Unlike other anxiety disorders, post-traumatic stress disorder is associated with diminished responsivity in the rostral anterior cingulate cortex and adjacent ventral medial prefrontal cortex. Additional research will be needed to (1) clarify the exact role of each component of the fear circuitry in the anxiety disorders, (2) determine whether functional abnormalities identified in the anxiety disorders represent acquired signs of the disorders or vulnerability factors that increase the risk of developing them, (3) link the findings of functional neuroimaging studies with those of neurochemistry studies, and (4) use functional neuroimaging to predict treatment response and assess treatment-related changes in brain function.
Engineering signal processing in cells: Towards molecular concentration band detection

We seek to couple protein-ligand interactions with synthetic gene networks in order to equip cells with the ability to process internal and environmental information in novel ways. In this paper, we propose and analyze a new genetic signal processing circuit that can be configured to detect various chemical concentration ranges of ligand molecules. These molecules freely diffuse from the environment into the cell. The circuit detects acyl-homoserine lactone ligand molecules, determines if the molecular concentration falls within two prespecified thresholds, and reports the outcome with a fluorescent protein. In the analysis of the circuit and the description of preliminary experimental results, we demonstrate how to adjust the concentration band thresholds by altering the kinetic properties of specific genetic elements, such as ribosome binding site efficiencies or dna-binding protein affinities to their operators.
What do glaciers tell us about climate variability and climate change

Glaciers respond to long-term climate changes and also to the year-to-year fluctuations inherent in a constant climate. Differentiating between these factors is critical for the correct interpretation of past glacier fluctuations and for the correct attribution of current changes. Previous work has established that century-scale, kilometre-scale fluctuations can occur in a constant climate. This study asks two further questions of practical significance: how likely is an excursion of a given magnitude in a given amount of time, and how large a trend in length is statistically significant? A linear model permits analytical answers wherein the dependencies on glacier geometry and climate setting can be clearly understood. The expressions are validated with a flowline glacier model. The likelihood of glacier excursions is well characterized by extreme-value statistics, although probabilities are acutely sensitive to some poorly known glacier properties. Conventional statistical tests can be used for establishing the significance of an observed glacier trend. However, it is important to determine the independent information in the observations which can be effectively estimated from the glacier geometry. Finally, the retreat of glaciers around Mount Baker, Washington State, USA, is consistent with, but not independent proof of, the regional climate warming that is established from the instrumental record.
Efficient amide-directed catalytic asymmetric hydroboration.

A series of acyclic β,γ-unsaturated amides are shown to undergo highly regio- (>95%) and enantioselective (93−99% ee) rhodium-catalyzed hydroboration with pinacolborane (PinBH) using simple chiral monophosphite or phosphoramidite ligands in combination with Rh(nbd)2BF4. The most effective ligands identified are phosphoramidite 4, derived from BINOL and N-methylaniline, and phosphite 5c, prepared from the (4‘-tert-butyl)phenyl TADDOL analogue and phenol. For example, (E)-3-hexenoic acid phenylamide ((E)-1) undergoes rhodium-catalyzed hydroboration with PinBH (0.5 mol % Rh(nbd)2BF4, 1.1 mol % BINOL-derived phosphoramidite 4, THF, 40 °C, 2 h) affording an intermediate boronate ester which after oxidation with basic hydrogen peroxide gives the β-hydroxy amide, (S)-3-hydroxyhexanoic acid phenylamide ((S)-3), in good yield (80%) and high enantiomeric purity (99% ee). Isomeric disubstituted (E)- and (Z)-alkenes give nearly identical results, and a trisubstituted alkene substrate is also shown to undergo efficien...
Empirical methods for compound splitting

Compounded words are a challenge for NLP applications such as machine translation (MT). We introduce methods to learn splitting rules from monolingual and parallel corpora. We evaluate them against a gold standard and measure their impact on performance of statistical MT systems. Results show accuracy of 99.1% and performance gains for MT of 0.039 BLEU on a German-English noun phrase translation task.
Palladium catalyzed coupling of organostannanes with vinyl epoxides

Abstract The coupling reaction of organotin reagents with vinyl epoxides, catalyzed by palladium, takes place at ambient temperatures, regioselectively, giving predominately the 1,4-addition product. Both aryl- and vinylstannanes undergo coupling in high yields, while acetylenic, allylic and benzylic tin reagents either give low yields or fail to couple. Although the double bond geometry in the vinylstannane partner is maintained in the coupled product, the double bond geometry from the vinyl epoxide is an E/Z mixture. In coupling reactions with cyclic 1,3-diene monoepoxides, the reaction is stereospedfic with the organic group from the tin partner coupling trans to the alcohol function.
SO4 SYMMETRY IN A HUBBARD MODEL

For a simple Hubbard model, using a particle-particle pairing operator η and a particle-hole pairing operator ζ, it is shown that one can write down two commuting sets of angular momenta operators J and J′, both of which commute with the Hamiltonian. These considerations allow the introduction of quantum numbers j and j′, and lead to the fact that the system has SO4 = (SU2 × SU2)/Z2 symmetry. j is related to the existence of superconductivity for a state and j′ to its magnetic properties.
Hardness of approximate two-level logic minimization and PAC learning with membership queries

Producing a small DNF expression consistent with given data is a classical problem in computer science that occurs in a number of forms and has numerous applications. We consider two standard variants of this problem. The first one is two-level logic minimization or finding a minimum DNF formula consistent with a given complete truth table (TT-MinDNF). This problem was formulated by Quine in 1952 and has been since one of the key problems in logic design. It was proved NP-complete by Masek in 1979. The best known polynomial approximation algorithm is based on a reduction to the SET-COVER problem and produces a DNF formula of size O([email protected]?OPT), where d is the number of variables. We prove that TT-MinDNF is NP-hard to approximate within d^@c for some constant @c>0, establishing the first inapproximability result for the problem. The other DNF minimization problem we consider is PAC learning of DNF expressions when the learning algorithm must output a DNF expression as its hypothesis (referred to as proper learning). We prove that DNF expressions are NP-hard to PAC learn properly even when the learner has access to membership queries, thereby answering a long-standing open question due to Valiant [L.G. Valiant, A theory of the learnable, Comm. ACM 27 (11) (1984) 1134-1142]. Finally, we provide a concrete connection between these variants of DNF minimization problem. Specifically, we prove that inapproximability of TT-MinDNF implies hardness results for restricted proper learning of DNF expressions with membership queries even when learning with respect to the uniform distribution only.
Static negative energies near a domain wall

Abstract We show that a system of a domain wall coupled to a scalar field has static negative energy density at certain distances from the domain wall. This system provides a simple, explicit example of violation of the averaged weak energy condition and the quantum inequalities by interacting quantum fields. Unlike idealized systems with boundary conditions or external background fields, this calculation is implemented precisely in renormalized quantum field theory with the energy necessary to support the background field included self-consistently.
OXYGEN TRANSFER REACTIONS: CATALYSIS BY RHENIUM COMPOUNDS

Publisher Summary This chapter deals with the transfer of an atom—usually oxygen, occasionally sulfur—from one species to another. The catalytic capabilities of rhenium compounds burst on the scene about one decade ago, featuring MeReO3 as a catalyst for reactions of hydrogen peroxide. It was quickly verified that peroxorhenium(VII) compounds were the active intermediates. With them, practical reactions and fundamental questions of mechanism could then be resolved. A new generation of oxorhenium compounds has now been prepared. They catalyze oxidation reactions of a different type, and appear to function by a different mechanism. They are oxorhenium(V) compounds that form usually metastable dioxorhenium(VII) intermediates. The mechanisms feature ReV(O)-to-ReVII(O)2 interconversions and catalyze oxygen-atom transfer reactions. The mechanisms show certain diversity as to the steps that enter in a kinetic sense.
Raman measurement in gas flows using a high-power laser diode

We present a technique to perform noninvasive, spatially- resolved measurements on low pressure, subsonic, laminar gas flows using Raman spectroscopy. From the Raman signal, the density and temperature conditions of the flow can be extracted directly, with reasonably low integration times. The use of a high power laser diode adds to the simplicity of the measurement, plus it makes it a very attractive low cost, efficient technique. Temperature regimes studied are from 290 K - 725 K, spatial resolution obtained is approximately 2.5 X 1.5 mm2 in the flow cross section, and 10-30 micrometers in the flow direction, within a flow profile of diameter approximately 1.5 cm. The flow was generated by a conical double nozzle system with CO2 at the center and Ar as sheath gas. The goal of the measurements is to study the gas dynamical focusing obtained, which will be used for future experiments on highly nonvolatile compounds.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
On the excess attenuation of sound in the atmosphere

The attenuation suffered by a sound wave propagating from an elevated source to the ground, in excess of spherical spreading losses and classical and molecular absorption effects, is studied. Reported discrepancies between attenuation measurements made in the field and the predictions of theories based only on absorption effects are discussed. It is concluded that atmospheric dynamics (turbulence) is a major contributor to the attenuation of sound waves propagating vertically in the atmosphere. Earlier theories on the attenuation of sound due to scattering have led to predictions of a strong (square‐law) frequency dependence and relatively large magnitudes which are not supported by the available field data. The present theory predicts a square‐law frequency dependence only for the special case of a homogeneous, isotropic medium. For a medium such as the atmosphere, with an inhomogeneous, anisotropic outer scale, a much milder frequency dependence is predicted which approaches a cube‐root dependence for t...
Comovement, excess volatility, and home production

Abstract Two investment anomalies in aggregate home-production models are investigated: excess volatility and comovement. Adjustment cost in capital accumulation reduces both volatility and the negative correlation in investments on capital goods in the market and at home. Investments comove to the extent that durable goods and time are good substitutes in consumption activities. Consumers substitute durable goods for time at home when the opportunity cost of time is high during booms. Based on the Consumer Expenditure Survey, I show that households’ expenditure shares on durable goods are negatively associated with leisure, indicating that durable goods are relatively good substitutes for time.
Negative Electron Affinity Effects And Schottky Barrier Height Measurements Of Metals On Diamond (100) Surfaces

In this study copper and cobalt films have been deposited on natural type IIb single crystal semiconducting diamond (100) surfaces in ultra-high vacuum (UHV). Prior to metal deposition the diamond crystals have been cleaned by a 1150°C anneal in UHV. This treatment resulted in positive electron affinity surfaces. Upon deposition of 2A of Cu or Co a negative electron affinity (NEA) was observed. Schottky barrier heights of 0.70 eV and 0.35 eV were found for Cu and Co respectively. In-situ Auger electron spectroscopy (AES) was employed to confirm the presence of a metal layer.
Parametric inference in the large data limit using maximally informative models

Motivated by data-rich experiments in transcriptional regulation and sensory neuroscience, we consider the following general problem in statistical inference: when exposed to a high-dimensional signal S, a system of interest computes a representation R of that signal, which is then observed through a noisy measurement M. From a large number of signals and measurements, we wish to infer the "filter" that maps S to R. However, the standard method for solving such problems, likelihood-based inference, requires perfect a priori knowledge of the "noise function" mapping R to M. In practice such noise functions are usually known only approximately, if at all, and using an incorrect noise function will typically bias the inferred filter. Here we show that in the large data limit, this need for a precharacterized noise function can be circumvented by searching for filters that instead maximize the mutual information I[M; R] between observed measurements and predicted representations. Moreover, if the correct filter lies within the space of filters being explored, maximizing mutual information becomes equivalent to simultaneously maximizing every dependence measure that satisfies the data processing inequality. It is important to note that maximizing mutual information will typically leave a small number of directions in parameter space unconstrained. We term these directions diffeomorphic modes and present an equation that allows these modes to be derived systematically. The presence of diffeomorphic modes reflects a fundamental and nontrivial substructure within parameter space, one that is obscured by standard likelihood-based inference.
Puncture of gravitating domain walls

We investigate the semi-classical instability of vacuum domain walls to processes where the domain walls decay by the formation of closed string loop boundaries on their worldvolumes. Intuitively, a wall which is initially spherical may `pop', so that a hole corresponding to a string boundary component on the wall, may form. We find instantons, and calculate the rates, for such processes. We show that after puncture, the hole grows exponentially at the same rate that the wall expands. It follows that the wall is never completely thermalized by a single expanding hole; at arbitrarily late times there is still a large, thin shell of matter which may drive an exponential expansion of the universe. We also study the situation where the wall is subjected to multiple punctures. We find that in order to completely annihilate the wall by this process, at least four string loops must be nucleated. We argue that this process may be relevant in certain brane-world scenarios, where the universe itself is a domain wall.
Oscillations of finite liquid columns

Abstract The resonance frequencies of cylindrical liquid bridges spanned between coaxial circular disks are investigated. First, the oscillations of infinite liquid columns are determined, which are periodic in time but damped in axial direction. For each frequency, an infinite set of such oscillations is obtained. Second, turning to finite columns linear combinations of these axially damped oscillations are formed, which satisfy the boundary conditions on the flow velocity at the supporting disks. The resulting infinite sums are truncated by restricting satisfaction of the boundary conditions to a finite number of circles. The fluiddynamic pressure onto the disks is calculated. The maxima at the resonance frequencies clearly decrease in sharpness and eventually vanish with increasing viscosity and decreasing surface tension of the liquid used. The explicit dependence of the resonance frequencies on the aspect ratio between length and diameter of the liquid columns and their viscosity and surface tension is given. Off-resonance, in particular at high frequencies, the length of the columns actually accelerated by the vibrating disk is found to correspond to 30 percent of their diameter.
Effect of Deck Deterioration on Overall System Behavior, Resilience and Remaining Life of Composite Steel Girder Bridges

During the past few decades, several studies have been conducted to characterize the performance of in-service, girder-type bridge superstructures under operating conditions. Few of these efforts have focused on evaluating the actual response of the bridge systems, especially beyond the elastic limit of their behavior, and correlating the impact of damage to the overall system behavior. In practice, most of the in-service bridge superstructures behave elastically under the routine daily traffic. However, existing damage and deteriorating conditions would significantly influence different aspects of the structural performance, including reserve capacity, resilience and remaining service-life. The main purpose of this study is to evaluate the response of composite steel girder bridges under the effect of subsurface delamination in the reinforced concrete deck. Commercial finite element computer software, ANSYS, was implemented to perform a nonlinear analysis on a representative single-span, simply-supported bridge superstructure. The system failure characteristics were captured in the numerical models by incorporating different sources of material non-linearities, including cracking/crushing in the concrete and plasticity in steel components. Upon validation, non-linear behavior of the system, with both intact and degraded configurations, was used to evaluate the impact of integrated damage mechanism on the overall system performance. Reserve capacity of this bridge superstructure was also determined with respect to the nominal element-level design capacity. As vision to the future path, this framework can be implemented to evaluate the performance of other in-service bridges degraded under the effect of different damage scenarios, thus providing a mechanism to determine a measure of capacity, resilience and remaining service-life.
Diastereoselective azomethine ylide cycloadditions to unsaturated, chiral bicyclic lactams

Abstract The levels of diastereoselection resulting from the 1,3-dipolar cycloaddition of chiral and achiral azomethine ylides 2 (a–c) to chiral, unsaturated bicyclic lactams 1 (a–f) are described in terms of steric factors.
Ni(COD)2/4-ClC6H4COR-catalyzed addition reactions of arylboroxines with aldehydes

Abstract Ni(COD) 2 /4-ClC 6 H 4 COR (R = H, CH 3 , Ph) was found to be an efficient catalyst system for the addition reactions of arylboroxines with aromatic and aliphatic aldehydes. The catalytically active species for Ni(COD) 2 /4-ClC 6 H 4 COR catalyst systems was likely to be their oxidative addition adducts, 4-RCOC 6 H 4 Ni(II)Cl(COD) complexes.
Patterns and factors associated with intensive use of ED services: implications for allocating resources.

Abstract Aim This study aims to better understand the patterns and factors associated with the use of emergency department (ED) services on high-volume and intensive (defined by high volume and high-patient severity) days to improve resource allocation and reduce ED overcrowding. Methods This study created a new index of “intensive use” based on the volume and severity of illness and a 3-part categorization (normal volume, high volume, intensive use) to measure stress in the ED environment. This retrospective, cross-sectional study collected data from hospital clinical and financial records of all patients seen in 2001 at an urban academic hospital ED. Results Multiple logistic regression models identified factors associated with high volume and intensive use. Factors associated with intensive days included being in a motor vehicle crash; having a gun or stab wound; arriving during the months of January, April, May, or August; and arriving during the days of Monday, Tuesday, or Wednesday. Factors associated with high-volume days included falling from 0 to 10 ft; being in a motor vehicle crash; arriving during the months of January, April, May, or August; and arriving during the days of Monday, Tuesday, or Wednesday. Conclusion These findings offer inputs for reallocating resources and altering staffing models to more efficiently provide high-quality ED services and prevent overcrowding.
Straddling the tholeiitic/calc-alkaline transition: the effects of modest amounts of water on magmatic differentiation at Newberry Volcano, Oregon

Melting experiments have been performed at 1 bar (anhydrous) and 1- and 2-kbar H2O-saturated conditions to study the effect of water on the differentiation of a basaltic andesite. The starting material was a mafic pumice from the compositionally zoned tuff deposited during the ~75 ka caldera-forming eruption of Newberry Volcano, a rear-arc volcanic center in the central Oregon Cascades. Pumices in the tuff of Newberry caldera (TNC) span a continuous silica range from 53 to 74 wt% and feature an unusually high-Na2O content of 6.5 wt% at 67 wt% SiO2. This wide range of magmatic compositions erupted in a single event makes the TNC an excellent natural laboratory in which to study the conditions of magmatic differentiation. Our experimental results and mineral–melt hygrometers/thermometers yield similar estimates of pre-eruptive H2O contents and temperatures of the TNC liquids. The most primitive (mafic) basaltic andesites record a pre-eruptive H2O content of 1.5 wt% and a liquidus temperature of 1,060–1,070 °C at upper crustal pressure. This modest H2O content produces a distinctive fractionation trend that is much more enriched in Na, Fe, and Ti than the calc-alkaline trend typical of wetter arc magmas, but slightly less enriched in Fe and Ti than the tholeiitic trend of dry magmas. Modest H2O contents might be expected at Newberry Volcano given its location in the Cascade rear arc, and the same fractionation trend is also observed in the rim andesites of the rear-arc Medicine Lake volcano in the southern Cascades. However, the Na–Fe–Ti enrichment characteristic of modest H2O (1–2 wt%) is also observed to the west of Newberry in magmas erupted from the arc axis, such as the Shevlin Park Tuff and several lava flows from the Three Sisters. This shows that modest-H2O magmas are being generated directly beneath the arc axis as well as in the rear arc. Because liquid lines of descent are particularly sensitive to water content in the range of 0–3 wt% H2O, they provide a quantitative and reliable tool for precisely determining pre-eruptive H2O content using major-element data from pumices or lava flows. Coupled enrichment in Na, Fe, and Ti relative to the calc-alkaline trend is a general feature of fractional crystallization in the presence of modest amounts of H2O, which may be used to look for “damp” fractionation sequences elsewhere.
Preparation of siloxacyclopentene containing 1,3-dienes and their Diels–Alder reactions

A number of enynyloxy dimethyl and diisopropyl silanes have been prepared and converted into siloxacyclopentene containing 1,3-dienes via intramolecular hydrosilylation of the alkyne functional group. Diels–Alder reactions of these dienes are reported.
Bayesian Clustering of Transcription Factor Binding Motifs

Genes are often regulated in living cells by proteins called transcription factors that bind directly to short segments of DNA in close proximity to specific genes. These binding sites have a conserved nucleotide appearance, which is called a motif. Several recent studies of transcriptional regulation require the reduction of a large collection of motifs into clusters based on the similarity of their nucleotide composition. We present a principled approach to this clustering problem based on a Bayesian hierarchical model that accounts for both within- and between-motif variability. We use a Dirichlet process prior distribution that allows the number of clusters to vary and we also present a novel generalization that allows the core width of each motif to vary. This clustering model is implemented, using a Gibbs sampling strategy, on several collections of transcription factor motif matrices. Our stochastic implementation allows us to examine the variability of our results in addition to focusing on a set ...
Experimental results for massive blowing studies.

Abstract : Previous work on the problem of massive blowing is described. A technique for visualizing the streamline separating the blown gas from that of the oncoming stream is developed, in which a chemiluminescent reaction along the separation streamline appears as a yellow glow and is easily photographed. Data for a variety of aerodynamic shapes over a wide range of flow conditions were obtained. A major result is that the separation streamline is essentially straight for a wedge- or cone-shaped model. Pressure distributions measured on the surface of wedge and cone models indicate that the pressure decays from high values near the leading edge of blowing to low values near the trailing edge. (Author)
Design and test of non-evacuated solar collectors with compound parabolic concentrators

The intermediate range of concentration ratios (1.5X–10X) which can be achieved with CPCs without diurnal tracking provides both economic and thermal advantages for solar collector design even when used with non-evacuated absorbers. The present paper summarizes more than 3 yr of research on non-evacuated CPCs and reviews measured performance data and critical design considerations. Concentrations in the upper portions of the practical range (e.g. 6X) can provide good efficiency (40–50 per cent) in the 100–160°C temperature range with relatively frequent tilt adjustments (12–20 times per year). At lower concentrations (e.g. 3X) performance will still be substantially better than that for a double glazed flat plate collector above about 70°C and competitive below, while requiring only semi-annual adjustments for year round operation. In both cases the cost savings associated with inexpensive reflectors, and the optimal coupling to smaller, simple inexpensive absorbers (e.g. tubes, fins, etc.) can be as important an advantage as the improved thermal performance. The design problems for non-evacuated CPC collectors are entirely different from those for CPC collectors with evacuated receivers. For example, heat loss through the reflector can become critical, since ideal CPC optics demands that the reflector extend all the way to the absorber. Recent improvements in reflector surfaces and low cost antireflection coatings have made practical a double-glazed non-evacuated CPC design. It is calculated that a 1.5X version of such a collector would have an optical efficiency ηo = 0.71, a heat loss coefficient U = 2.2 W/m2°C and a heat extraction effciency factor F′ ≥ 0.98, while requiring no tilt adjustments.
NOISELESS OPTICAL AMPLIFICATION OF IMAGES

We used a spatially broadband optical parametric amplifier for image amplification. In the phase-sensitive configuration of the amplifier, we observed noiseless amplification of input images. For a gain of $\ensuremath{\simeq}2.5$, we measured noise-figure values of ( $0.2\ifmmode\pm\else\textpm\fi{}0.6$) and ( $0.4\ifmmode\pm\else\textpm\fi{}0.5$) dB, respectively, for two amplifiers of different lengths. These experimental values agree with theory (for an ideal noiseless amplifier the noise figure is 0 dB) and are almost 2 dB lower than the quantum limit of an ideal phase-insensitive amplifier.
Families of quasimodular forms and Jacobi forms: The crank statistic for partitions

Families of quasimodular forms arise naturally in many situations such as curve counting on Abelian surfaces and counting ramified covers of orbifolds. In many cases the family of quasimodular forms naturally arises as the coefficients of a Taylor expansion of a Jacobi form. In this note we give examples of such expansions that arise in the study of partition statistics. The crank partition statistic has gathered much interest recently. For instance, Atkin and Garvan showed that the generating functions for the moments of the crank statistic are quasimodular forms. The two variable generating function for the crank partition statistic is a Jacobi form. Exploiting the structure inherent in the Jacobi theta function we construct explicit expressions for the functions of Atkin and Garvan. Furthermore, this perspective opens the door for further investigation including a study of the moments in arithmetic progressions. We conduct a thorough study of the crank statistic restricted to a residue class modulo 2.
Preparation and chemistry of Me3SiCH2AsH2; preparation of [Me3SiCH2(H)AsGaPh2]3, a trimeric mono(arsino)gallane containing a hydrogen bonded to arsenic. Isolation and X-ray crystal structure of (Me3SiCH2As)5

Abstract Reduction of Me3SiCH2AsCl2 (I) with LiA1H4 at −78°C afforded Me3SiCH2 AsH2 (II) and reaction of II with Ph3Ga produced [Me3SiCH2(H)AsGaPh2]3 (III) which was characterized by partial elemental analysis (C and H), 1H NMR spectroscopy and a cryoscopic molecular weight determination. Based on 1H NMR data, [Me3SiCH2 (H)AsGaMe2]3 (IV) was produced by the reaction of II with Me3Ga; however, only H2, Me4Si, (Me3SiCH2As)5 (VI) and unreacted (Me3SiCH2)3Ga were identified after allowing the latter to react with II. Reaction of 2 equiv. of Me3SiCl with a mixture of II and n-BuLi (1 : 2 mole ratio) afforded Me3SiCH2As(SiMe3)2 (V). The monosilylated arsine was not isolated when 1 equiv. of Me3SiCl was allowed to react with combined II and n-BuLi (1 : 1 mole ratio); rather, a mixture of II and V resulted. Attempted preparations of (Me3SiCH2AsGaPh)n, are described. The ring compound, VI, was prepared by reaction of I with a mixture of Me3SiCl and Mg in THF. The molecular structure of this cycloarsane was determined by single-crystal X-ray diffraction methods. Pale yellow crystals of VI belong to the monoclinic system with four molecules occupying the general positions of space group P21/c(C2h5)with cell constants: a = 9.952(1), b = 30.245(9), c = 13.000(3) A, β = 91.69(1)°, V = 3911.3 A 3, Z = 4.
Suppression of circular Bragg phenomenon in chiral sculptured thin films produced with simultaneous rocking and rotation of substrate during serial bideposition

Chiral sculptured thin films (STFs) produced by substrate rotation during physical vapor deposition exhibit the circular Bragg phenomenon, whereby normally incident left- and right-circularly polarized plane waves are discriminated in a spectral regime called the circular Bragg regime. Theory had predicted that substrate rocking, in synchrony with substrate rotation, during deposition could suppress the propensity to exhibit the circular Bragg phenomenon. Therefore chiral STFs of a dielectric material were fabricated with/without substrate rocking, and their transmittance spectrums for incident linearly and circularly polarized plane waves were measured. With sufficient rocking amplitude, the discrimination between incident left- and right-circularly polarized light nearly vanished, whereas a Bragg phenomenon for all normally incident plane waves was observed. Thus, chiral STF technology can be used to produce both ordinary and circular-polarization Bragg filters.
Toward a definition and understanding of correlation for variables constrained by random relations

Random relations are random sets defined on a two-dimensional space (or higher). After defining the correlation for two variables constrained by a random relation as an interval, the effect of imprecision was studied by using a multi-valued mapping, whose domain is a space of joint random variables. This perspective led to the notions of consistent and non-consistent marginals, which parallel those of epistemic independence, and unknown interaction and epistemic independence for random sets, respectively. The calculation of the correlation bounds entails solving two optimisation problems that are NP-hard. When the entire random relation is available, it is shown that the hypothesis of non-consistent marginals leads to correlation bounds that are much larger (four orders of magnitude in some cases) than those obtained under the hypothesis of consistent marginals; this hierarchy parallels the hierarchy between probability bounds for unknown interaction and strong independence, respectively. Solutions of the...
Formation, migration, and clustering of delocalized vacancies and interstitials at a solid-state semicoherent interface

Atomistic simulations are used to study the formation, migration, and clustering of delocalized vacancies and interstitials at a model fcc-bcc semicoherent interface formed by adjacent layers of Cu and Nb. These defects migrate between interfacial trapping sites through a multistep mechanism that may be described using dislocation mechanics. Similar mechanisms operate in the formation, migration, and dissociation of interfacial point defect clusters. Effective migration rates may be computed using the harmonic approximation of transition state theory with a temperature-dependent prefactor. Our results demonstrate that delocalized vacancies and interstitials at some interfaces may be viewed as genuine defects, albeit governed by mechanisms of higher complexity than conventional point defects in crystalline solids.
Particle track record of Apollo 15 green soil and rock

Track densities, track stability, and uranium contents have been measured in lunar samples containing abundant green glass spherules from stations 6a and 7 of the Apollo 15 mission. This glass is rather homogeneous in its track registration properties but nonuniform in its uranium content, specific gravity, and bulk etching rate. The major components of a soil sample, 15401, are found to have had an unusually short surface exposure (500,000 yr) and to have been stirred at least once, but not often during its lifetime. A nearby soil clod, 15426, appears to have been brought to the surface in the same event. 15405, the rock upon which 15401 was perched, has recorded deformation features and track densities compatible with its surface residence having begun at the same time.
APR: a geographic information system based primary router for underground residential distribution design

This paper presents an automated tool for optimizing the routing of primary cables in underground residential distribution systems (URD). Although initially developed as one of the modules in Puget Sound Power and Light Co.'s automated electrical plant design program, Automated Primary Router (APR) can also be used in standalone mode. APR, implemented in a geographic information system (GIS)-based environment, is capable of efficiently accessing and manipulating geographically referenced data from a facilities management system database. It also provides a full-fledged graphic user interface, along with on-line visualization and accurate cost estimation to facilitate the design process. APR employs a heuristic search algorithm to find the best primary cable routes either for new residential developments, or for existing URD systems as part of the ongoing cable replacement program. Based on the test results, APR shows significant stability and efficiency in finding the optimal solution for primary cable routing. With this performance, APR can help distribution engineers improve the quality of URD design, producing standardized and economically justifiable primary cable routes. Because geographically referenced design data are digitally stored in the GIS database, APR further increases the reusability and accessibility of the URD design information. >
WAGE‐MODERATING EFFECTS OF CORPORATISM: DECENTRALIZED VERSUS CENTRALIZED WAGE SETTING IN A UNION, FIRM, GOVERNMENT CONTEXT

Corporatism is often claimed to exert a moderating influence on the real wage gap, the difference between the actual wage rate and the full employment wage rate. Corporatist countries should, therefore, show a lesser degree of unemployment. This paper explores and models one of the reasons why these results might be observed. An important reason for wage moderation could be the endogeneity of the wage tax rate for a centralized or encompassing trade union. Copyright 1993 by Blackwell Publishers Ltd and The Victoria University of Manchester
Single crystal growth from light, volatile and reactive materials using lithium and calcium flux

We present a method for the solution growth of single crystals from reactive Li and Ca melts and its application to the synthesis of several, representative compounds. Among these, single crystalline LiN, Li(Li)N with = {Mn, Fe, Co}, LiCaN, LiC, LiRh and LiIr from Li-rich flux, as well as CaN, CaNi, CaNi, YbNi, YNi and LaNi from Ca-rich flux could be obtained. Special emphasize is given on the growth of nitrides using commercially available LiN and CaN powders as the nitrogen source instead of N gas.
Oxydehydrogenation of ethane over ZSM-5 zeolite catalysts: Effect of steam

Abstract The Oxydehydrogenation of ethane over zeolite based catalysts (H+, Na+-, Ni2+-, Pt+-, Ga3+-, and [V]-ZSM-5) was studied in the temperature range 450–600°C. Selectivity to ethylene and higher hydrocarbons close to 80% was achieved at 550 °C. Basic (Na-ZSM-5) and neutral ([V]-ZSM-5) zeolite catalysts were shown to be more active and selective for the Oxydehydrogenation of ethane than ZSM-5 in acid form. In addition to the Oxydehydrogenation product, a significant amount of higher hydrocarbons (C3+) was produced when using zeolites containing Ga3+-, Pt2+-, or Ni2+- cations. Na+-, V5+-, and H+-exchanged ZSM-5 catalyst are less effective in facilitating the production of higher hydrocarbons (Ca3+). Steam often has a profound effect on the performance of zeolite based catalysts. The addition of steam can enhance their selectivity to hydrocarbon products and reduce their tendency to form methane. Relatively high conversion (ca. 43%) and high selectivity (ca. 78%) to hydrocarbons were achieved at temperatures around 550 °C. Higher reaction temperature results in significant increase of the formation of methane while lower reaction temperature leads to lower selectivity to hydrocarbon products.
Information infrastructure tools for bioterrorism preparedness

As this paper was aimed at finding dual/multiple-use for the bioterrorism technology made possible by the large infusion of funds to the states and territories through the Center for Disease Control and Prevention request for proposals (CDC RFP), its six Focus Areas serve as vertical criteria on the figures that follow. The CDC RFP holds this prominent role, as the CDC was the agency tapped by DHHS to monitor the use of the funds and associated performance. The CDC's six Focus Areas (with Focus Area D, Laboratory Capacity - Chemical Agents apparently not funded this year) include: Focus Area A: Preparedness Planning and Readiness Assessment (including the National Pharmaceutical Stockpile (NPS) and associated response), Focus Area B: Surveillance and Epidemiology Capacity, Focus Area C: Laboratory Capacity iologic Agents, Focus Area E: Health Alert Network/Communications and Information Technology, Focus Area F: Communicating Health Risks and Health Information Dissemination, and Focus Area G: Education & Training. It should be noted that the importance of dual/multiple-use notwithstanding, the initial defined use of bioterrorism funds for each Focus Area (as outlined by the Congressional funding and latter elaborated on by DHHS and the CDC) should be met first. Thus, it is the goal of this article to accomplish both this and to find extensible systems capable of response to, and detection of, multiple emergency disasters or outbreak situations.
Large-scale oligonucleotide synthesis by the H-phosphonate method

Abstract The H-phosphonate method is capable of giving good yields, on scales in the area of 14 μmole, with as little as 2eq of monomer. Under these conditions, however, capping was found to be necessary. Cyanoethyl H-phosphonate has been introduced for this purpose and shown to be effective.
An X-Ray Reprocessing Model of Disk Thermal Emission in Type 1 Seyfert Galaxies

Using a geometry consisting of a hot central Comptonizing plasma surrounded by a thin accretion disk, we model the optical through hard X-ray spectral energy distributions of the type 1 Seyfert. galaxies NGC 3516 and NGC 7469. As in the model proposed by Poutanen, Krolik, and Ryde for the X-ray binary Cygnus X-1 and later applied to Seyfert galaxies by Zdziarski, Lubifiski, and Smith, feedback between the radiation reprocessed by the disk and the thermal Comptonization emission from the hot central plasma plays a pivotal role in determining the X-ray spectrum, and as we show, the optical and ultraviolet spectra as well. Seemingly uncorrelated optical/UV and X-ray light curves, similar to those which have been observed from these objects can, in principle, be explained by variations in the size, shape, and temperature of the Comptonizing plasma. Furthermore, by positing a disk mass accretion rate which satisfies a condition for global energy balance between the thermal Comptonization luminosity and the power available from accretion, one can predict the spectral properties of the heretofore poorly measured hard X-ray continuum above approximately 50 keV in type 1 Seyfert galaxies. Conversely, forthcoming measurements of the hard X-ray continuum by more sensitive hard X-ray and soft gamma-ray telescopes, such as those aboard the International Gamma-Ray Astrophysics Laboratory (INTEGRAL) in conjunction with simultaneous optical, UV, and soft X-ray monitoring, will allow the mass accretion rates to be directly constrained for these sources in the context of this model.
THE DISSAVING OF ANNUITY WEALTH AND MARKETABLE WEALTH IN RETIREMENT

This paper compares the automatic dissaving of annuity wealth with the discretionary dissaving of marketable wealth that would result from life-cycle consumption behavior by retired persons. In simulations of a life-cycle model based on the isoelastic utility function and realistic parameter values, we find that marketable wealth normally would be dissaved more rapidly than annuity wealth. This suggests that empirical findings that show the opposite relation-slow dissaving of marketable wealth being accompanied by faster dissaving of annuity wealth (or total wealth)-should not be interpreted as evidence that supports the life-cycle theory.
New methods for lossless image compression using arithmetic coding

Abstract We give a new paradigm for lossless image compression, with four modular components: pixel sequence, prediction, error modeling and coding. We present two new methods (called MLP and PPPM) for lossless compression, both involving linear prediction, modeling prediction errors by estimating the variance of a Laplace distribution, and coding using arithmetic coding applied to precomputed distributions. The MLP method is both progressive and parallelizable. We give results showing that our methods perform significantly better than other currently used methods for lossless compression of high resolution images, including the proposed JPEG standard. We express our results both in terms of the compression ratio and in terms of a useful new measure of compression efficiency, which we call compression gain.