cssi/SciSciGPT-SciSciNet huggingface dataset:
Parameterization of cloud droplet formation in large-scale models: Including effects of entrainment

[1] This work offers for the first time a comprehensive parameterization suitable for large-scale models which is robust, computationally efficient, and from first principles links chemical effects, aerosol heterogeneity and entrainment with cloud droplet formation. The parameterization is based on the entraining ascending parcel model framework; mixing of outside air is parameterized in terms of a per-length entrainment rate. The integration of the droplet growth is done using the “population splitting” concept of Nenes and Seinfeld (2003). Formulations for lognormal and sectional aerosol representations are given, as well as simplifications that allow the treatment of entrainment with high computational efficiency without loss of accuracy. The concept of “critical entrainment,” a value beyond which droplet activation is not favored, is introduced and shown that it is important for defining (1) whether or not entrainment effects have an impact on droplet formation and (2) the characteristic temperature and pressure for cloud droplet formation. The performance of the parameterization was evaluated against a detailed numerical parcel model over a comprehensive range of droplet formation conditions. The agreement is always very good (mean relative error 2.3% ± 21%); errors tend to increase as entrainment approaches the critical value, but are never above 40%.
Crossed rolls at onset of convection in a rigid box

Calcul des nombres de Rayleigh critiques, des configurations en rouleaux et des derivees de vitesse de croissance au seuil de convection pour un boite rigide avec des plaques inferieure et superieure conductrices et des parois laterales isolees
Cocommutative Hopf Algebras of Permutations and Trees

Consider the coradical filtrations of the Hopf algebras of planar binary trees of Loday and Ronco and of permutations of Malvenuto and Reutenauer. We give explicit isomorphisms showing that the associated graded Hopf algebras are dual to the cocommutative Hopf algebras introduced in the late 1980's by Grossman and Larson. These Hopf algebras are constructed from ordered trees and heap-ordered trees, respectively. These results follow from the fact that whenever one starts from a Hopf algebra that is a cofree graded coalgebra, the associated graded Hopf algebra is a shuffle Hopf algebra.
Changes in peripheral blood cells in mice after injection with benzo(a)pyrene during pregnancy.

AbstractPregnant C3H/Anfcum mice were injected ip with 150 ug benzo-(a)pyrene (BP)/g body weight at the second trimester (12 days). Quantitative and differential changes were assayed in the peripheral blood leukocytes and erythrocytes at various times before and after mating and treatment. Within 5 days after injection, a 2- to 4-fold reduction in leukocytes was observed when compared to controls [corn oil (vehicle for BP)-injected pregnant females] which persisted into the 10th postpartum day. The erythrocytes were also significantly reduced but not to the same degree (1.2- to 1.5-fold). Depression in white blood cells is attributed to lymphocyte depletion since the granulocytes were virtually unchanged and the lymphocyte to granulocyte ratio, ordinarily >2 was 1 or < one. No change in monocytes was observed and none of the cell populations, including the erythrocytes, appeared to be abnormal (e.g., no increase in reticulocytes). A moderate reduction (1.5-fold) in erythrocytes and leukocytes also occurre...
THE SCHWARZSCHILD SOLUTION IN THE DGP MODEL

We discuss the Schwarzschild solution in the Dvali–Gabadadze–Porrati (DGP) model. We obtain a perturbative expansion and find the explicit form of the lowest-order contribution. By keeping off-diagonal terms in the metric, we arrive at a perturbative expansion which is valid both far from and near the Schwarzschild radius. We calculate the lowest-order contribution explicitly and obtain the form of the metric both on the brane and in the bulk. As we approach the Schwarzschild radius, the perturbative expansion yields the standard four-dimensional Schwarzschild solution on the brane which is non-singular in the decoupling limit. This non-singular behavior is similar to the Vainshtein solution in massive gravity demonstrating the absence of the van Dam–Veltman–Zakharov (vDVZ) discontinuity in the DGP model.
The Cost of Firearm Deaths in the United States: Reduced Life Expectancies and Increased Insurance Costs

The United States remains far behind most other affluent countries in terms of life expectancy. One of the possible causes of this life expectancy gap is the widespread availability of firearms and the resulting high number of U.S. firearm fatalities: 10,801 homicides in 2000. The European Union experienced 1,260 homicides, Japan only 22. Using multiple decrement techniques, I show that firearm violence shortens the life of an average American by 104 days (151 days for white males, 362 days for black males). Among all fatal injuries, only motor vehicle accidents have a stronger effect. I estimate that the elimination of all firearm deaths in the United States would increase the male life expectancy more than the total eradication of all colon and prostate cancers. My results suggest that the insurance premium increases paid by Americans as a result of firearm violence are probably of the same order of magnitude as the total medical costs due to gunshots or the increased cost of administering the criminal justice system due to gun crime.
Neutron Diffraction Studies of Magnetic Materials

The ability of neutron diffraction in determining the nature and extent of magnetic ordering is illustrated for the intermetallic compounds, Y6(Fe,Mn)23, and ErFe3. Substitution with other 3d transition metals influences the Fe-Fe exchange forces such as to alter, sometimes considerably, the magnetic properties, e.g., local site magnetic anisotropies in Er(Fe,Ni)3 and thermal expansion anomalies in the R2 (Fe,Co)14B compounds. When the 3d atoms are near neighbors in the periodic chart, their nuclear scattering lengths for neutrons are sufficiently different to permit the detection of preferential occupation of the several nonequivalent crystallographic 3d metal sites, i.e., atomic ordering, present in the R6M23, and R2Fe14B structures.
The analysis of foreign exchange data using waveform dictionaries

Abstract This paper uses waveform dictionaries to decompose the signals contained within three foreign exchange rates using tick-by-tick observations obtained world wide. The three exchange rates examined are the Japanese Yen and the German Deutsche Mark against the U.S. dollar and the Deutsche Mark against the Yen. The data were provided by Olsen Associates. A wabeform dictionary is a class of transforms that generalizes both windowed Fourier transforms and wavelets. Each waveform is parameterized by location, frequency, and scale. Such transforms can analyze signals that have highly localized structures in either time or frequency space as well as broad band structures; that is, waveforms can, in principle, detect everything from shocks represented by Dirac Delta functions, to short bursts of energy within a narrow band of frequencies, to the presence of frequencies that occur sporadically, and finally to the presence of frequencies that hold over the entire observed period. Waveform dictionaries are most useful in analyzing data that are not stationary and non-stationarity up to second order is well recognized in the context of foreign exchange rates.
Characterizing the disk around the TW Hydrae Association brown dwarf 2MASSW J1207334-393254

We present detailed modeling of the disk around the TW Hydrae Association (TWA) brown dwarf 2MASSW J1207334-393254 (2M1207), using Spitzer observations from 3.6 to 24 ?m. The spectral energy distribution (SED) does not show a high amount of flaring. We have obtained a good fit using a flat disk of mass between 10-4 and 10 -6 M?, 10-11 M? yr-1, and a large inclination angle between 60? and 70?. We have used three different grain models to fit the 10 ?m Si emission feature, and have found the results to be consistent with ISM-like dust. In comparison with other TWA members, this suggests lesser dust processing for 2M1207, which could be explained by mechanisms such as aggregate fragmentation and/or turbulent mixing. We have found a good fit using an inner disk radius equal to the dust sublimation radius, which indicates the absence of an inner hole in the disk. This suggests the presence of a small K - L' excess, similar to the observed K - [3.6] excess.
Rapid self-assembly of uranyl polyhedra into crown clusters.

Clusters built from 32 uranyl peroxide polyhedra self-assemble and crystallize within 15 min after combining uranyl nitrate, ammonium hydroxide, and hydrogen peroxide in aqueous solution under ambient conditions. These novel crown-shaped clusters are remarkable in that they form so quickly, have extraordinarily low aqueous solubility, form with at least two distinct peroxide to hydroxyl ratios, and form in very high yield. The clusters, which have outer diameters of 23 A, topologically consist of eight pentagons and four hexagons. Their rapid formation and low solubility in aqueous systems may be useful properties at various stages in an advanced nuclear energy system.
A methodology for solute transport in unsteady, nonuniform streamflow with subsurface interaction

Abstract An advection-dispersion-reaction model can generally be used to describe one-dimensional stream solute transport if the flow is steady and if the channel is smooth and uniform. When applied to unsteady, nonuniform streamflows, a model based on the Fickian analogy needs to be modified to account for the temporal and spatial variation of the cross-sectional area of the stream channel. In this paper, we explore this topic with a simple approximation method as well as an elaborate one, both of which are incorporated into a conjunctive stream–aquifer transport model and are applied to a hypothetical stream–aquifer setting. The simple method, while easier to implement, displays a persistent pattern of error in simulation results. The elaborate method, while accurate in computation, results in a more complicated model and requires extensive procedures to overcome the efficiency problem when simulating complex stream–aquifer interactions. However, by coupling the latter with the adaptive stepsize control for the Runge–Kutta method in a conjunctive stream–aquifer model, it not only greatly improves model efficiency but also results in more realistic modeling than previously reported.
Compact Lattice QED with Staggered Fermions and Chiral Symmetry Breaking

Abstract Different formulations of the 4d compact lattice QED with staggered fermions (standard Wilson and modified by suppression of lattice artifacts) are investigated by Monte Carlo simulations within the quenched approximation. We show that after suppressing lattice artifacts the system undergoes a phase transition from the Coulomb phase into a presumably weakly chirally broken phase only at (unphysical) negative β-values.
P38 MAPK in pancreatic cancer: Finding a protective needle in the haystack

Activated p38 MAPK alpha (pp38α) is a good prognostic marker in pancreatic ductal adenocarcinoma (PDAC) that could be used to personalize therapy. pp38α suppresses JNK-mediated proliferation, both in vitro and in vivo. The current findings support testing of combination therapies that include JNK targeting and/or suppressing negative regulators of pp38α.
Growth-Based Franchise Opportunities: Lessons from the GEICO Acquisition

Private equity acquirers often purchase underperforming businesses and then cut costs and otherwise turn those businesses around for later sale. This approach has worked incredibly well, so much so that it has attracted a great deal of competition thereby making similar deals increasingly scarce. A potentially lucrative alternative to such deals are growth-based franchise opportunities. A “franchise” is Graham and Dodd nomenclature for a firm operating with a sustainable competitive advantage. A growth-based franchise opportunity arises when a franchise has unrecognized growth potential and thus can be purchased at a reasonable “margin of safety,” or discount from estimated value. The classic example of such an opportunity is Warren Buffett’s 1995 GEICO acquisition. This article presents an approach for identifying, evaluating, and tracking the value realization of growth-based franchise deals in the context of the GEICO case. The approach integrates strategic, financial, and performance management concepts in a way that, it is hoped, will prove useful to future acquirers and researchers alike.
MLCT excited states of cuprous bis-phenanthroline coordination compounds

Cuprous bis-phenanthroline compounds possess metal-to-ligand charge transfer, MLCT, excited states. Phenanthroline ligands coordinated to Cu(I) that are disubstituted in the 2- and 9-positions with alkyl or aryl groups, abbreviated CuI(phen′)2+, have long-lived excited states at room temperature. The parent CuI(phen)2+ compound is non-emissive under the same conditions with a short excited state lifetime, τ<10 ns. Disubstitution in the 2,9-positions stabilizes the Cu(I) state and increases the energy gap between the MLCT and the ground state. The prototypical and most well studied compound is CuI(dmp)2+, where dmp is 2,9-(CH3)2-1,10-phenanthroline. In dichloromethane solution at room temperature, CuI(dmp)2+ displays broad MLCT absorption with λmax=454 nm, a broad unstructured emission with λmax=730 nm, and an excited state lifetime of 85 ns. The emission arises from two closely spaced MLCT excited states, separated in energy by 1800 cm−1, that behave as one state at room temperature. CuI(dmp)2+* excited states are quenched in the presence of Lewis bases and coordinating solvents. A 5-coordinate excited state complex, or exciplex, is proposed to account for temperature dependent quenching data. The substantial inner-sphere reorganizational energy changes that follow light excitation are novel features of these MLCT excited states. This review attempts to cover all the existing data reported on CuI(phen′)2+ excited states and contrast it with well-known MLCT behavior of (dπ)6 transition metal compounds.
Polymer-Bound Carbonic Anhydrides in N -Acylation of 7-Aminocephalosporanic Acid

Abstracts P 7-Aminocephalosporanic acid tert-butyl ester was reacted with polystyrene-bound mixed carbonic-carboxylic anhydrides to give the corresponding N-acylated derivatives. Cleavage of the tert-butyl protecting group with trifluoroacetic acid gave the corresponding cephalosporanic acid.
Wide-Range Monitor for Pulsed X-Ray Sources

A monitoring instrument based on a high-pressure ionization chamber has been developed that measures average dose rates as low as 0.1 mR/h and responds linearly to short pulses at dose rates up to 1.2 x 10/sup 10/ R/h. Its sensitivity can be remotely changed by a factor of 10/sup 4/, to enable accurate measurement of both background radiation and very high intensities such as can be expected from accelerator beam-spills. The instrument's detector-electrometer pulse response was measured using a dose-calibrated field-emission accelerator having a 30-ns pulse width.
National Estimates of Gross Employment and Job Flows from the Quarterly Workforce Indicators with Demographic and Industry Detail.

The Quarterly Workforce Indicators (QWI) are local labor market data produced and released every quarter by the United States Census Bureau. Unlike any other local labor market series produced in the US or the rest of the world, QWI measure employment flows for workers (accession and separations), jobs (creations and destructions) and earnings for demographic subgroups (age and gender), economic industry (NAICS industry groups), detailed geography (block (experimental), county, Core-Based Statistical Area, and Workforce Investment Area), and ownership (private, all) with fully interacted publication tables. The current QWI data cover 47 states, about 98% of the private workforce in those states, and about 92% of all private employment in the entire economy. State participation is sufficiently extensive to permit us to present the first national estimates constructed from these data. We focus on worker, job, and excess (churning) reallocation rates, rather than on levels of the basic variables. This permits a comparison to existing series from the Job Openings and Labor Turnover Survey and the Business Employment Dynamics Series from the Bureau of Labor Statistics (BLS). The national estimates from the QWI are an important enhancement to existing series because they include demographic and industry detail for both worker and job flow data compiled from underlying micro-data that have been integrated at the job and establishment levels by the Longitudinal Employer-Household Dynamics Program at the Census Bureau. The estimates presented herein were compiled exclusively from public-use data series and are available for download.
Finite Affine Groups: Cycle Indices, Hall–Littlewood Polynomials, and Probabilistic Algorithms

Abstract The study of asymptotic properties of the conjugacy class of a random element of the finite affine group leads one to define a probability measure on the set of all partitions of all positive integers. Four different probabilistic understandings of this measure are given—three using symmetric function theory and one using Markov chains. This leads to non-trivial enumerative results. Cycle index generating functions are derived and are used to compute the large dimension limiting probabilities that an element of the affine group is separable, cyclic, or semisimple and to study the convergence to these limits. The semisimple limit involves both Rogers–Ramanujan identities. This yields the first examples of such computations for a maximal parabolic subgroup of a finite classical group.
HOW OBSERVATIONS OF CIRCUMSTELLAR DISK ASYMMETRIES CAN REVEAL HIDDEN PLANETS : PERICENTER GLOW AND ITS APPLICATION TO THE HR 4796 DISK

Recent images of the disks of dust around the young stars HR 4796A and Fomalhaut show, in each case, a double-lobed feature that may be asymmetric (one lobe may be brighter than the other). A symmetric double-lobed structure is that expected from a disk of dust with a central hole that is observed nearly edge-on (i.e., close to the plane of the disk). This paper shows how the gravitational influence of a second body in the system with an eccentric orbit would cause a brightness asymmetry in such a disk by imposing a forced eccentricity on the orbits of the constituent dust particles, thus shifting the center of symmetry of the disk away from the star and causing the dust near the forced pericenter of the perturbed disk to glow. Dynamic modeling of the HR 4796 disk shows that its ~5% brightness asymmetry could be the result of a forced eccentricity as small as 0.02 imposed on the disk by either the binary companion HR 4796B or by an unseen planet close to the inner edge of the disk. Since it is likely that a forced eccentricity of 0.01 or higher would be imposed on a disk in a system in which there are planets but no binary companion, the corresponding asymmetry in the disk's structure could serve as a sensitive indicator of these planets that might otherwise remain undetected.
Watertight cataract incision closure using fibrin tissue adhesive

Purpose To determine whether a simple method for applying fibrin tissue adhesive to a clear corneal cataract incision can create a watertight seal. Setting Laboratory investigation. Methods Clear corneal cataract incisions were simulated in 8 eye-bank eyes. In 4 eyes, fibrin adhesive was applied to the incision in a simple manner; the other 4 eyes were controls with no adhesive. Each eye was tested under low pressure conditions to detect fluid ingress of India Ink on the eye's surface. The eyes were tested again with external compression to distort the incision to detect fluid egress. Results In the eyes with fibrin adhesive, there was no egress of fluid with incision distortion and no ingress of India Ink. In the 4 eyes without adhesive, there was ingress and egress of fluid. Conclusion A simple method of applying fibrin adhesive to cataract incisions created a watertight seal.
Soft Ideals and Arithmetic Mean Ideals

This article investigates the soft-interior (se) and the soft-cover (sc) of operator ideals. These operations, and especially the first one, have been widely used before, but making their role explicit and analyzing their interplay with the arithmetic mean operations is essential for the study in [10] of the multiplicity of traces. Many classical ideals are ‘soft’, i.e., coincide with their soft interior or with their soft cover, and many ideal constructions yield soft ideals. Arithmetic mean (am) operations were proven to be intrinsic to the theory of operator ideals in [6, 7] and arithmetic mean operations at infinity (am-∞) were studied in [10]. Here we focus on the commutation relations between these operations and soft operations. In the process we characterize the am-interior and the am-∞ interior of an ideal.
REAR-END COLLISION-WARNING SYSTEM: DESIGN AND EVALUATION VIA SIMULATION

The design of an innovative rear-end collision-warning system was evaluated for effectiveness. The crash scenario involves a lead vehicle not moving (LVNM) in one lane of a straight, dry, paved arterial road and a following vehicle approaching in the same lane. The LVNM has a rearfacing sensor and is equipped with the rear crash-warning system, which allows the LVNM to flash its brake lights or its center high-mounted stop lamp, warning the following vehicle that it is approaching too rapidly. Because this problem is complex, the scope was narrowed, and it was assumed that the driver of the following vehicle always detected the warning after a response time lag and then applied hard braking. The warning algorithm (i.e., selecting the most appropriate warning distance for each approaching vehicle speed) was designed based on trade-offs to maximize the capability of preventing crashes, reduce the frequency of nuisance alarms, and minimize the severity of crashes. The overall measures of effectiveness of the...
Methodology for Clinical Investigation of Ventilator-Associated Pneumonia : Epidemiology and Therapeutic Intervention

aspirates. These criteria are inaccurate in as many as 60 percent of cases compared to autopsy or quantitative cultures of bronchoscopic specimens. Many recent studies of VAP have focused on the accuracy of bronchoscopic and other methods of obtaining uncontaminated specimens from the lower respiratory tract for diagnosis. In anticipation of the use of these more accurate techniques to validate conclusions derived from studies based on the clinical diagnosis of VAP, the appropriateness of the design and conclusions of these published studies have been reviewed. In this communication, we discuss the areas in which sufficient data exist to reach consensus regarding methods for future studies in the epidemiology, treatment, and prevention of VAP and also attempt to delineate areas for future research endeavors. EPIDEMIOLOGIC DEFINITION OF VENTILATOR-ASSOCIATED PNEUMONIA
Synthesis and Triplex Forming Properties of an Acyclic N7-Glycosylated Guanine Nucleoside

A chiral acyclic nucleoside, one in which the ribose carbohydrate has been replaced with a glycerol-based linker, is prepared by glycosylating guanine at the N7-nitrogen. The stereochemically pure derivative is converted to a DMT-protected phosphoramidite for incorporation into DNA sequences. Sequence containing the acyclic N7-dG nucleoside are capable of forming DNA triplexes in which it is likely that the N1-H and N2-amino groups of the N7-dG are involved in recognition of the guanine base in G-C base pairs.
More on the cut and choose game

Abstract The cut and choose game G c&c (B) is one of the infinitary games on a complete Boolean algebra B introduced by Jech. We prove that existence of a winning strategy for II in G c&c (B) implies semiproperness of B. If the existence of a supercompact cardinal is consistent then so is “for every ℵ 1 - distributive algebra B II has a winning strategy in G c&c (B) ”.
Enantioselective Pictet-Spengler-type cyclizations of hydroxylactams: H-bond donor catalysis by anion binding.

Highly enantioenriched indolizinone and quinolizinone products are obtained in the thiourea-catalyzed cyclization of tryptamine-derived hydroxylactams. Substituent and counterion effect studies point to a novel mechanism of catalysis involving rate-limiting anion abstraction and binding by the thiourea.
Sensitivity of the bond strength to the structure of the interface between reinforcement and cement, and the variability of this structure

The variability in interfacial structure and the sensitivity of the bond strength to this variation were studied for each of the interfaces between carbon fiber and cement paste, between stainless steel fiber and cement paste, and between steel rebar and concrete. The interfacial structural variation was indicated by the variation in the contact electrical resistivity. The interface between steel rebar and concrete had least variability but most sensitivity. The interface between carbon fiber and cement paste had less variability but more sensitivity than that between steel fiber and cement paste.
New Directions for American Education: A Black Perspective

(1970). New directions for American education: A black perspective. The Speech Teacher: Vol. 19, No. 2, pp. 111-116.
Control over stress induces plasticity of individual prefrontal cortical neurons: A conductance-based neural simulation

Behavioral control over stressful stimuli induces resilience to future conditions when control is lacking. The medial prefrontal cortex(mPFC) is a critically important brain region required for plasticity of stress resilience. We found that control over stress induces plasticity of the intrinsic voltage-gated conductances of pyramidal neurons in the PFC. To gain insight into the underlying biophysical mechanisms of this plasticity we used the conductance- based neural simulation software tool, NEURON, to model the increase in membrane excitability associated with resilience to stress. A ball and stick multicompartment conductance-based model was used to realistically fit passive and active data traces from prototypical pyramidal neurons in neurons in rats with control over tail shock stress and those lacking control. The results indicate that the plasticity of membrane excitability associated with control over stress can be attributed to an increase in Na+ and Ca2+ T-type conductances and an increase in the leak conductance. Using simulated dendritic synaptic inputs we observed an increase in excitatory postsynaptic summation and amplification resulting in elevated action potential output. This realistic simulation suggests that control over stress enhances the output of the PFC and offers specific testable hypotheses to guide future electrophysiological mechanistic studies in animal models of resilience and vulnerability to stress.
A kinetic model for cobalt gradient formation during liquid phase sintering of functionally graded WC-Co

Abstract Functionally graded WC–Co composites offer solutions to the trade-off between wear resistance and fracture toughness in WC–Co composites. Although liquid phase sintering is the most economical and viable method for producing WC–Co parts, the main challenge in fabricating a functionally graded WC–Co composite using liquid phase sintering is that the cobalt content homogenizes across the layers resulting in a sintered part with a uniform cobalt content. However, a cobalt gradient can be established after sintering by introducing an initial gradient in carbon within a WC–Co bi-layer prior to sintering. In this paper, a kinetic model is used to describe the graded microstructure as a function of sintering time and temperature as well as other factors including the volume fraction of Co3W3C (η) phase, liquid migration pressure and carbon content. The model predicts that the rate of the increase of the thickness of the WC–Co product layer with respect to the sintering time reduces with the volume fraction of η phase. This is attributed to the effect of the phase reactions between the carbon and η phase. A good agreement is observed between the model and experimental results.
Status of non-Riemannian cosmology

Abstract We provide a brief chronological guide to the literature on non-Riemannian cosmological models. Developments in this field are traced back to the early seventies and are given in table form.
The Influence of Sheet Metal Anisotropy on Laser Forming Process

Cold-rolled sheet metal that is often used in laser forming exhibits anisotropic properties, which are mostly caused by preferred orientations of grains developed during the severe plastic deformation such as cold rolling. In the present study, the textures of cold-rolled mild steel sheets are characterized and the influence of the plastic anisotropy on laser forming process is investigated. Deformation textures are measured in terms of pole figures and orientation distribution function (ODF) plots obtained through electron backscatter diffraction (EBSD). The anisotropy index (R-value) of the material with different rolling reductions is obtained by uniaxial tensile tests. Both are compared and agree with the texture development theory. Effects of the plastic anisotropy on bending deformation during the laser forming process are investigated experimentally and numerically. Various conditions including different laser power, scanning speed, and number of scans for sheets of different rolling reductions are considered and results are discussed. The simulation results are consistent with the experimental observations.
An optimal stopping approach to land development under uncertainty

The Arrow-Fisher-Henry (AFH) analysis of land development under uncertainty has been conducted in a two period model. Recently, Capozza and Helsley (1990) and Batabyal (1996, 1997) have addressed the question of land development under uncertainty in a multi-period setting. We extend aspects of this literature by analyzing the multi-period land development question in an optimal stopping framework. In particular, we characterize the optimal decision rule governing the development of land, given that the objective of a landowner is to maximize the total revenue from development.
A versatile VLSI fast Fourier transform processor

A versatile special-purpose VLSI fast Fourier transform (FFT) processor is presented. It can process variant data sizes of FFT and cooperate with other identical FFT processors to accomplish cascade and parallel FFT processing schemes. The operations of the single processor FFT processing scheme, the multiprocessor cascade FFT processing scheme, and the multiprocessor parallel FFT processing scheme are described. The results of performance analysis show that the combination of adaptive architecture capability and VLSI technology can provide a practical solution for meeting the goal of advanced real-time FFT processing.
Surface sputtering from cold dark matter interactions: proposed search for its diurnal modulation

Abstract Nuclear recoil cascades induced by Cold Dark Matter (CDM) elastic scattering can produce the ejection of target atoms from solid surfaces. We calculate the yield and energy distribution of these sputtered atoms in a variety of materials. These parameters would suffer a large diurnal modulation induced by the rotation of the Earth and its motion through the galactic halo. Schemes for the detection of this unique CDM signature are proposed.
Quiver theories, soliton spectra and Picard-Lefschetz transformations

Quiver theories arising on D3-branes at orbifold and del Pezzo singularities are studied using mirror symmetry. We show that the quivers for the orbifold theories are given by the soliton spectrum of massive 2d N=2 theory with weighted projective spaces as target. For the theories obtained from the del Pezzo singularities we show that the geometry of the mirror manifold gives quiver theories related to each other by Picard-Lefschetz transformations, a subset of which are simple Seiberg duals. We also address how one indeed derives Seiberg duality on the matter content from such geometrical transitions and how one could go beyond and obtain certain ``fractional Seiberg duals.'' Moreover, from the mirror geometry for the del Pezzos arise certain Diophantine equations which classify all quivers related by Picard-Lefschetz. Some of these Diophantine equations can also be obtained from the classification results of Cecotti-Vafa for the 2d N=2 theories.
Daily fluid balance predicts hospital mortality in critically ill patients receiving continuous renal replacement therapy.

It has been suggested that fluid balance is a biomarker in critically ill patients [1]. There is a paucity of randomized trials examining the effect of daily fluid balance on outcomes in patients on continuous renal replacement therapy (CRRT). The RENAL trial did not find mortality difference with higher CRRT dose [2], but did not investigate the effect of daily fluid balance on patient outcomes. A post hoc analysis suggested survival benefit in patients with negative fluid balance [3]. In this study, we hypothesize that daily fluid balance is an independent predictor of mortality in critically ill patients.
On the Energetics of Advection‐dominated Accretion Flows

Using mean field MHD, we discuss the energetics of optically thin, two-temperature, advection-dominated accretion flows (ADAFs). If the magnetic field is tangled and roughly isotropic, flux freezing is insufficient to maintain the field in equipartition with the gas. In this case we expect a fraction of the energy generated by shear in the flow to be used to build up the magnetic field strength as the gas flows in; the remaining energy heats the particles. We argue that strictly equipartition magnetic fields are incompatible with a priori reasonable levels of particle heating; instead, the plasma β in ADAFs (≡ gas pressure divided by magnetic/turbulent pressure) is likely to be 5; correspondingly, the viscosity parameter α is likely to be 0.2.
Evasiveness of Subgraph Containment and Related Properties

We prove new results on evasiveness of monotone graph properties by extending the techniques of Kahn, Saks, and Sturtevant [ Combinatorica, 4 (1984), pp. 297--306]. For the property of containing a subgraph isomorphic to a fixed graph, and a fairly large class of related n-vertex graph properties, we show evasiveness for an arithmetic progression of values of n. This implies a $\frac12n^2 - O(n)$ lower bound on the decision tree complexity of these properties. We prove that properties that are preserved under taking graph minors are evasive for all sufficiently large n. This greatly generalizes a theorem due to Best, van Emde Boas, and Lenstra [A Sharpened Version of the Aanderaa--Rosenberg Conjecture, Report ZW 30/74, Mathematisch Centrum, Amsterdam, The Netherlands, 1974] which states that planarity is evasive. We prove a similar result for bipartite subgraph containment.
Disjoinable Lagrangian spheres and dilations

We consider open symplectic manifolds which admit dilations (in the sense previously introduced by Solomon and the author). We obtain restrictions on collections of Lagrangian submanifolds which are pairwise disjoint (or pairwise disjoinable by Hamiltonian isotopies) inside such manifolds. This includes the Milnor fibres of isolated hypersurface singularities which have been stabilized (by adding quadratic terms) sufficiently often.
Joint Universal Lossy Coding and Identification of Stationary Mixing Sources

The problem of joint universal source coding and modeling, treated in the context of lossless codes by Rissanen, was recently generalized to fixed-rate lossy coding of finitely parametrized continuous-alphabet i.i.d. sources. We extend these results to variable-rate lossy block coding of stationary ergodic sources and show that, for bounded metric distortion measures, any finitely parametrized family of stationary sources satisfying suitable mixing, smoothness and Vapnik-Chervonenkis learnability conditions admits universal schemes for joint lossy source coding and identification. We also give several explicit examples of parametric sources satisfying the regularity conditions.
THE ARIZONA RADIO OBSERVATORY CO MAPPING SURVEY OF GALACTIC MOLECULAR CLOUDS. III. THE SERPENS CLOUD IN CO J = 2-1 AND 13CO J = 2-1 EMISSION

We mapped 12CO and 13CO J = 2-1 emission over 1.04 deg2 of the Serpens molecular cloud with 38'' spatial and 0.3 km s–1 spectral resolution using the Arizona Radio Observatory Heinrich Hertz Submillimeter Telescope. Our maps resolve kinematic properties for the entire Serpens cloud. We also compare our velocity moment maps with known positions of young stellar objects (YSOs) and 1.1 mm continuum emission. We find that 12CO is self-absorbed and 13CO is optically thick in the Serpens core. Outside of the Serpens core, gas appears in filamentary structures having LSR velocities which are blueshifted by up to 2 km s–1 relative to the 8 km s–1 systemic velocity of the Serpens cloud. We show that the known Class I, flat, and Class II YSOs in the Serpens core most likely formed at the same spatial location and have since drifted apart. The spatial and velocity structure of the 12CO line ratios implies that a detailed three-dimensional radiative transfer model of the cloud will be necessary for full interpretation of our spectral data. The "starless cores" region of the cloud is likely to be the next site of star formation in Serpens.
600-year sedimentary archive of hurricane strikes in a prograding beach ridge plain, southwestern Louisiana

Abstract This study tests a novel approach to paleotempestology, substituting the lateral time-depth of a prograding beach ridge plain for the vertical time-depth of an aggrading coastal lake, pond, lagoon, swamp or marsh. Trenching and coring of a beach ridge plain in southwestern Louisiana revealed six sand beds and one shell bed, interpreted as hurricane washover deposits. The sand beds are readily distinguished from enclosing marsh sediments by their higher sand content, lower organic content and contrasting microfossil assemblages. Based on the modern analogs of hurricanes Audrey (1957), Rita (2005) and Ike (2008), and consideration of nearby landfalling hurricanes in the historical record, it was determined that the storm intensity threshold of the study site is equivalent to a Category 3 hurricane. There is a wide variation in hurricane strike frequency between this site and other sites bordering the Gulf of Mexico. This variation results from differences in site sensitivity and the nature of geologic or geochemical proxies used to derive hurricane strike records. The approach demonstrated by this study could have applicability at other sites around the world where beach ridge plains are subject to tropical cyclone strikes.
Seven trees in one

Abstract Following a remark of Lawvere, we explicitly exhibit a particularly elementary bijection between the set T of finite binary trees and the set T7 of seven-tuples of such trees. “Particularly elementary” means that the application of the bijection to a seven-tuple of trees involves case distinctions only down to a fixed depth (namely four) in the given seven-tuple. We clarify how this and similar bijections are related to the free commutative semiring on one generator X subject to X = 1 + X2. Finally, our main theorem is that the existence of particularly elementary bijections can be deduced from the provable existence, in intuitionistic type theory, of any bijections at all.
Reaction of a superoxochromium(III) ion with nitrogen monoxide: Kinetics and mechanism

The kinetics of the rapid reaction between CraqOO2+ and NO were determined by laser flash photolysis of CraqNO2+ in O2-saturated acidic aqueous solutions, k = 7 × 108 M-1 s-1 at 25° C. The reaction produces an intermediate, believed to be NO2, which was scavenged with ([14]aneN4)Ni2+. With limiting NO, the CraqOO2+/NO reaction has a 1:1 stoichiometry and produces both free NO3- and a chromium nitrato complex, CraqONO22+. In the presence of excess NO, the stoichiometry changes to [NO]/[CraqOO2+] = 3:1, and the reaction produces close to 3 mol of nitrite/mol of CraqOO2+. An intermediate, identified as a nitritochromium(III) ion, CraqONO2+, is a precursor to a portion of free NO2-. In the proposed mechanism, the initially produced peroxynitrito complex, CraqOONO2+, undergoes O−O bond homolysis followed by some known and some novel chemistry of CraqO2+ and NO2. The reaction between CraqO2+ and NO generates CraqONO2+, k > 104 M-1 s-1. CraqOO2+ reacts with NO2 with k = 2.3 × 108 M-1 s-1.
Understanding behavioral sources of process variation following enterprise system deployment

Abstract This paper extends the current understanding of the time-sensitivity of intent and usage following large-scale IT implementation. Our study focuses on perceived system misfit with organizational processes in tandem with the availability of system circumvention opportunities. Case study comparisons and controlled experiments are used to support the theoretical unpacking of organizational and technical contingencies and their relationship to shifts in user intentions and variation in work-processing tactics over time. Findings suggest that managers and users may retain strong intentions to circumvent systems in the presence of perceived task-technology misfit. The perceived ease with which this circumvention is attainable factors significantly into the timeframe within which it is attempted, and subsequently impacts the onset of deviation from prescribed practice and anticipated dynamics.
Agglomeration and Cost Economies for Washington State Hospital Services

Abstract Hospital cost efficiency is dependent on the potential to generate cost economies, which imply lower costs for hospitals that are, for example, larger or more diversified. Although scale and scope economies have been recognized in the literature on hospital costs, agglomeration economies due to hospital clustering have received little attention. We consider the impact of such spatial linkages, which may result from labor pooling or knowledge spillovers, by including a measure of other hospitals' proximity in a flexible cost function model. We find significant agglomeration economies for the Washington State hospitals in our dataset; geographic concentration appears to reduce costs for most treatment centers. We also find significant scale economies, and some evidence of scope economies from complementarities between outputs and among treatment centers.
A Fully Automated, Single-Connection Tester for T/R Modules

This paper was written from both a specific and general point of view. The discussion on the tester's instrument integration included an actual block diagram of the Sandia tester; this was done to provide a specific example of how the HP 85110A's access links can be utilized. On the other hand, the de-embedding discussion and analysis was carried out from a general point of view to be of maximum service to the reader: the expression one should use to de-embed a measurement is ultimately a function of the measurement environment and the accuracy desired. For example, the usefulness of some of the approximations was shown to be a function of the instrument's reflection coefficient at the measurement frequency.
The Expected Properties of Dark Lenses

We investigate the properties of multiple-image gravitational lens systems formed by dark matter halos. Both the Navarro-Frenk-White (NFW) and Moore et al. mass profiles are considered, and the effects of quadrupole perturbations to the lensing potential are taken into account. The systems produced by dark halos exhibit two generic properties that serve as powerful benchmarks for scrutinizing individual lens candidates: small flux ratios between the two brightest images in triples and detectable odd images. In contrast, most currently ambiguous quasar pairs consist of two components with flux ratios ≥3 : 1. Such systems are statistical outliers in the expected distribution of dark lenses and are therefore likely to be binary quasars.
A Resolved Circumstellar Disk around the Herbig Ae Star HD 100546 in the Thermal Infrared

We present mid-infrared nulling interferometric and direct imaging observations of the Herbig Ae star HD 100546 obtained with the Magellan I (Baade) 6.5 m telescope. The observations show resolved circumstellar emission at 10.3, 11.7, 12.5, 18.0, and 24.5 ?m. Through the nulling observations (10.3, 11.7, and 12.5 ?m), we detect a circumstellar disk, with an inclination of 45? ? 15? with respect to a face-on disk, a semimajor axis position angle of 150? ? 10? (east of north), and a spatial extent of about 25 AU. The direct images (18.0 and 24.5 ?m) show evidence for cooler dust with a spatial extent of 30-40 AU from the star. The direct images also show evidence for an inclined disk with a similar position angle as the disk detected by nulling. This morphology is consistent with models in which a flared circumstellar disk dominates the emission. However, the similarity in relative disk size that we derive for different wavelengths suggests that the disk may have a large inner gap, possibly cleared out by the formation of a giant protoplanet. The existence of a protoplanet in the system also provides a natural explanation for the observed difference between HD 100546 and other Herbig Ae stars.
Noble Gases in the Murchison Meteorite: Possible Relics of s-Process Nucleosynthesis

The Murchison carbonaceous chondrite contains a new type of xenon component, enriched by up to 50 percent in five of the nine stable xenon isotopes, mass numbers 128 to 132. This component is released at 1200 to 1600 C from a severely etched mineral fraction. Krypton shows a similar but smaller enrichment in the isotopes 80 and 82. Neon and helium released in the same interval also are quite anomalous, being highly enriched in the isotopes 22 and 3. These patterns are strongly suggestive of three nuclear processes believed to take place in red giants: the s process (neutron capture on a slow time scale), helium burning, and hydrogen shell burning. If this interpretation is correct, then primitive meteorites contain yet another kind of alien, presolar material: dust grains ejected from red giants.
DETECTION OF METHANE ON KUIPER BELT OBJECT (50000) QUAOAR

The near-infrared spectrum of (50000) Quaoar obtained at the Keck Observatory shows distinct absorption features of crystalline water ice, solid methane, and ethane, and possibly other higher order hydrocarbons. Quaoar is only the fifth Kuiper Belt object (KBO) on which volatile ices have been detected. The small amount of methane on an otherwise water ice-dominated surface suggests that Quaoar is a transition object between the dominant volatile-poor small KBOs and the few volatile-rich large KBOs such as Pluto and Eris.