cssi/SciSciGPT-SciSciNet huggingface dataset:
Adjuvant radiation for vulvar carcinoma : Improved local control

Abstract Purpose: Local recurrence is a significant problem following primary surgery for advanced vulva carcinoma. The objectives of this study were to evaluate the impact of adjuvant vulval radiation on local control in high risk patients and the impact of local recurrence on overall survival. Methods and Materials: From 1980–1994, 62 patients with invasive vulva carcinoma and either positive or close (less 8 mm) margins of excision were retrospectively studied. Thirty-one patients were treated with adjuvant radiation therapy to the vulva and 31 patients were observed after surgery. Kaplan-Meier estimates and the Cox proportional hazard regression model were used to evaluate the effect of adjuvant radiation therapy on local recurrence and overall survival. Independent prognostic factors for local recurrence and survival were also assessed. Results: Local recurrence occurred in 58% of observed patients and 16% in patients treated with adjuvant radiation therapy. Adjuvant radiation therapy significantly reduced local recurrence rates in both the close margin and positive margin groups ( p = 0.036, p = 0.0048). On both univariate and multivariate analysis adjuvant radiation and margins of excision were significant prognostic predictors for local control. Significant determinants of actuarial survival included International Federation of Gynecologists and Obstetricians (FIGO) stage, percentage of pathologically positive inguinal nodes and margins of excision. The positive margin observed group had a significantly poorer actuarial 5 year survival than the other groups ( p = 0.0016) and adjuvant radiation significantly improved survival for this group. The 2 year actuarial survival after developing local recurrence was 25%. Local recurrence was a significant predictor for death from vulva carcinoma (risk ratio 3.54). Conclusion: Local recurrence is a common occurrence in high risk patients. In this study adjuvant radiation therapy significantly reduced local recurrence rates and may improve overall survival in certain subgroups. As salvage rates after developing local recurrence are poor adjuvant vulvar radiation should be considered for patients at risk after primary surgery.
HVDC System Control for Damping of Subsynchronous Oscillations

A method for designing a supplemental subsynchronous damping control (SSDC) for an HVDC transmission system is described. The SSDC eliminates torsional instabilities caused by interaction between conventional HVDC controls and turbine-generator rotor torsional modes of vibration. Results of digital simulation used in the design process are compared with measurements made on an HVDC simulator. Results of both digital simulations and HVDC simulator tests which demonstrate SSDC performance are shown. This research and development effort was sponsored by EPRI under RP1425-1.
2,3-Dicyclohexylsuccinimide as a directing/protecting group for the regioselective glycosylation or alkylation of purines

Here we describe the synthesis and application of a novel 2,3-dicyclohexylsuccinimide (Cy2SI) protecting group towards regioselective purine glycosylation and alkylation reactions. This bulky protecting group promotes high regioselectivity during the glycosylation (as well as diastereoselectivity) or alkylation of purines using Hoffer's chlorosugar or tert-butyl bromoacetate, respectively. Cy2SI offers the additional synthetic advantage that other base-labile protecting groups, such as toluoyl esters, can be selectively removed in its presence without affecting the imide.
A useful conversion of alcohols to alkyl fluorides

Abstract A useful conversion of alcohols to alkyl fluorides via their fluoroformates is introduced. The fluoroformates are obtained in nearly quantitative yield from the alcohols by treatment with COF2 (generated in situ from bis(trichloromethyl) carbonate) in ether with KF as an added acid scavenger. The neat fluoroformates are cleaved to the fluorides by heating at 120–125°C using hexabutylguanidinium fluoride (HBGF) as the catalyst.
THE TLWP CATHODIC PROTECTION SYSTEM

This paper details the subsea corrosion protection system of the tension leg well platform (TLWP), which comprises coatings and cathodic protection (CP). Postinstallation surveys reveal potentials of at least 150 mV more protective than the minimum potential required for protection. The TLWP protection system weighs 434,000 lbm less than the conventional CP design, with 286,000 lbm less on the floating portion of the TLWP.
Incidence, Intensity, and Duration of Financial Stress among Farm Firms

Over the past year, evidence on the extent of farm financial stress became available (Melichar, Jolly). However, policy makers disagree not only about the size and significance of the farm debt problems but also about the type of intervention, if any, that would be appropriate. The objective of this paper is to provide a benchmark for subsequent policy discussion. Financial stress requires definition. The absence of normal profit or returns to factors cause financial stress, yet these same forces drive the allocative mechanism of a market economy. Financial stress occurs when the capacity of an individual or firm or a specific sector of the economy to adjust to the forces causing stress is exceeded. Some stress is essential for efficiency and growth. Too much financial stress may lead to misallocation of resources, undesirable structural change, loss of economic and human capital, needed institutions, and individual well-being. Two surveys are used in this report. The USDA Farm Costs and Returns Survey (FCRS) is a probability-based sample of 23,386 farm operators contacted by enumerators between 15 February and 8 March 1985. Of these initial contacts 73% participated in the survey (Johnson, Baum, and Prescott). The FCRS collected income, cost, and balance sheet data for farm operators. The second data source was a mail survey of 4,700 Iowa farm operators conducted in March 1985. The Iowa Crop Reporting Service requested information on 1984 and 1985 financial conditions and operator characteristics. Approximately 23% of the questionnaires were returned (Jolly and Barkema).
Computing linking numbers of a filtration

We develop fast algorithms for computing the linking number of a simplicial complex within a filtration. We give experimental results in applying our work toward the detection of non-trivial tangling in biomolecules, modeled as alpha complexes.
Social facilitation effects of virtual humans.

Objective: To investigate whether virtual humans produce social facilitation effects. Background: When people do an easy task and another person is nearby, they tend to do that task better than whe...
The DEEP2 Galaxy Redshift Survey: Clustering of Groups and Group Galaxies at z~1

We study the clustering properties of groups and of galaxies in groups in the DEEP2 Galaxy Redshift Survey data set at z ~ 1 in three separate fields covering a total of 2 deg2. Four measures of two-point clustering in the DEEP2 data are presented: (1) the group correlation function for 460 groups with estimated velocity dispersions of σ ≥ 200 km s-1; (2) the galaxy correlation for the full DEEP2 galaxy sample, using a flux-limited sample of 9800 objects in the range 0.7 ≤ z ≤ 1.0; (3) the galaxy correlation for galaxies in groups or in the field; and (4) the group-galaxy cross-correlation function. Our results are compared with mock group and galaxy catalogs produced from ΛCDM simulations. Using the observed number density and clustering amplitude of the DEEP2 groups, the estimated minimum group dark matter halo mass is Mmin ~ 6 × 1012 h-1 M☉. Groups are more clustered than galaxies in the DEEP2 data, with a relative bias of b = 1.17 ± 0.04 on scales rp = 0.5-15 h-1 Mpc. The correlation function of galaxies in groups has a steeper slope (γ ~ 2.12 ± 0.06) than for the full galaxy sample (γ ~ 1.74 ± 0.03), and both samples can be fit by a power law on scales rp = 0.05-20 h-1 Mpc. We empirically measure the contribution to the projected correlation function, wp(rp), for galaxies in groups from a "one-halo" term and a "two-halo" term. The projected cross-correlation between group centers and the full galaxy sample shows that red galaxies are more centrally concentrated in groups than blue galaxies at z ~ 1. DEEP2 galaxies in groups appear to have a shallower radial distribution than that of mock galaxy catalogs made from N-body simulations, which assume a central galaxy surrounded by satellite galaxies with an NFW profile. Using simulations with different halo model parameters, we show that the clustering of galaxies in groups can be used to place tighter constraints on the halo model than can be gained from using the usual galaxy correlation function alone.
Huffman algebras for independent random variables

Based on a rearrangement inequality by Hardy, Littlewood, and Polya, we define two-operator algebras for independent random variables. These algebras are called Huffman algebras since the Huffman algorithm on these algebras produces an optimal binary tree that minimizes the weighted lengths of leaves. Many examples of such algebras are given. For the case with random weights of the leaves, we prove the optimality of the tree constructed by the power-of-2 rule, i.e., the Huffman algorithm assuming identical weights, when the weights of the leaves are independent and identically distributed.
Synthesis, Characterization, and Oxygenation Studies of Carboxylate-Bridged Diiron(II) Complexes with Aromatic Substrates Tethered to Pyridine Ligands and the Formation of a Unique Trinuclear Complex

In this study, diiron(II) complexes were synthesized as small molecule mimics of the reduced active sites in the hydroxylase components of bacterial multicomponent monooxygenases (BMMs). Tethered aromatic substrates were introduced in the form of 2-phenoxypyridines, incorporating hydroxy and methoxy functionalities into windmill-type diiron(II) compounds [Fe(2)(μ-O(2)CAr(R))(2)-(O(2)CAr(R))(2)(L)(2)] (1-4), where (-)O(2)CAr(R) is a sterically encumbering carboxylate, 2,6-di(4-fluorophenyl)- or 2,6-di(p-tolyl)benzoate (R = 4-FPh or Tol, respectively). The inability of 1-4 to hydroxylate the aromatic substrates was ascertained. Upon reaction with dioxygen, compounds 2 and 3 (L = 2-(m-MeOPhO)Py, 2-(p-MeOPhO)Py, respectively) decompose by a known bimolecular pathway to form mixed-valent diiron(II,III) species at low temperature. Use of 2-(pyridin-2-yloxy)phenol as the ligand L resulted in a doubly-bridged diiron complex (4) and an unprecedented phenoxide-bridged triiron(II) complex (5) under slightly modified reaction conditions.
Rheology, Microstructure and Migration in Brownian Colloidal Suspensions

We demonstrate that suspended spherical colloidal particles can be effectively modeled as single dissipative particle dynamics (DPD) particles provided that the conservative repulsive force is appropriately chosen. The suspension model is further improved with a new formulation, which augments standard DPD with noncentral dissipative shear forces between particles while preserving angular momentum. Using the new DPD formulation we investigate the rheology, microstructure and shear-induced migration of a monodisperse suspension of colloidal particles in plane shear flows (Couette and Poiseuille). Specifically, to achieve a well-dispersed suspension we employ exponential conservative forces for the colloid-colloid and colloid-solvent interactions but keep the conventional linear force for the solvent-solvent interactions. Our simulations yield relative viscosity versus volume fraction predictions in good agreement with both experimental data and empirical correlations. We also compute the shear-dependent viscosity and the first and second normal-stress differences and coefficients in both Couette and Poiseuille flow. Simulations near the close packingvolume-fraction (64%) at low shear rates demonstrate a transition to flow-induced string-like structures of colloidal particles simultaneously with a transition to a nonlinear Couette velocity profile in agreement with experimental observations. After a sufficient increase ofthe shear rate the ordered structure melts into disorder with restoration of the linear velocity profile. Migration effects simulated in Poiseuille flow compare well with experiments and model predictions. The important role of angular momentum and torque in nondilute suspensions is also demonstrated when compared with simulations by the standard DPD, which omits the angular degrees of freedom. Overall, the new method agrees very well with the Stokesian Dynamics method but it seems to have lower computational complexity and is applicable to general complex fluids systems.
Efficient Pricing of European-Style Options under Heston's Stochastic Volatility Model

Heston’s stochastic volatility model is frequently employed by finance researchers and practitioners. Fast pricing of European-style options in this setting has considerable practical significance. This paper derives a computationally efficient formula for the value of a European-style put under Heston’s dynamics, by utilizing a transform approach based on inverting the characteristic function of the underlying stock’s log-price and by exploiting the characteristic function’s symmetry. The value of a European-style call is computed using a parity relationship. The required characteristic function is obtained as a special case of a more general solution derived in prior research. Computational advantage of the option value formula is illustrated numerically. The method can help to mitigate the time cost of algorithms that require repeated evaluation of European-style options under Heston’s dynamics.
Adaptive Nonlinear Huber-Based Navigation for Rendezvous in Elliptical Orbit

This paper discusses the development of an adaptive discrete-time robust nonlinear filtering technique, and the application of this technique to the six-degree-of-freedom elliptical orbit rendezvous and docking problem. The proposed adaptive nonlinear filtering technique is based on a robust modification of the divided-difference filtering method based on Huber's generalized maximum likelihood estimation, blended with a robust covariance matching procedure based on a modified Myers―Tapley method. In particular, the adaptive scheme can estimate the process noise and measurement noise covariance matrices along with the state estimate and state estimate error covariance matrix, which uses a robust approach to estimating these covariances that can resist the effects of outliers in the stored buffer of residuals.
Adaptive stabilization of uncertain nonholonomic mechanical systems

This paper presents a new adaptive controller as a solution to the problem of stabilizing nonholonomic mechanical systems in the presence of incomplete information concerning the system dynamic model. The proposed control system consists of two su bsystems: a slightly modified version of the kinematic stabilization strategy of M'Closkey and Murray which generates a desired velocity trajectory for the nonholonomic system, and an adaptive control scheme which ensures that this velocity trajector y is accurately tracked. This approach is shown to provide arbitrarily accurate stabilization to any desired configuration and can be implemented with no knowledge of the system dynamic model. The efficacy of the proposed stabilization strategy is illustr ated through extensive computer simulations with nonholonomic mechanical systems arising from explicit constraints on the system kinematics and from symmetries of the system dynamics.
Multichannel Kondo impurities in superconductors

Abstract We discuss the effect of multichannel Kondo impurities on superconductivity. In the strong coupling regime such impurities are pairbreakers, in contrast to the ordinary Kondon effect. Measurements of Tc-suppression may help in identifying impurities displaying this more exotic exchange coupling to the conduction band.
Nonstationary Random Parametric Vibration in Light Aircraft Landing Gear

In this work, a new approach for analysis of random vibration in light aircraft landing gear for a given duty cycle is developed and studied. The aircraft is modeled as a linear, single-degree-of-freedom oscillator with random properties, including nonstationary damping and random nonstationary load. Note that this type of problem is dife cult to analyze efe ciently using most conventional techniques. Two approaches to analyze the random vibration of the system are examined: a new variant of the random matrix approach, a statistical random vibration analysis method developed previously by the authors; and a hybrid Monte Carlo technique containing a spectral representation approach and a variant of Latin hypercube sampling. Random response results are shown for two light aircraft landing on three different terrain types using each method, and comparisons are offered. These results show that Monte Carlo analysis cannot compute accurate solutions for this problem. It is anticipated that the proposed random matrix technique could be used in conjunction with current fatigue analysis methods so that accurate landing gear fatigue information may be computed.
Highlights in the studies of the relationship of geomagnetic field changes to auroral luminosity.

In the middle of the 18th century Celsius observed that there was a correspondence between a great aurora in Europe and the extreme motion of his observed compass needle. By the nineteenth century it was well established that the geomagnetic field always fluctuated violently at the height of an auroral display, that the high latitude zones of peak field disturbance and luminosity had similar locations, and that there were concurrent solar cycle changes in activity levels for the two phenomena. After the International Geophysical Year of 1957 to 1959 the correspondence of the ionospheric electrojet currents and auroral forms became a focus of observational programs. In these recent times the studies of a relationship between short-period pulsations of the geomagnetic field and luminosity pulsations (or the pulsations of bombarding, low energy electrons causing the auroral intensity changes) appeared prominently in the literature. A summary of the scientific progress in the study of these phenomena is presented in this paper.
High-Gain Observers in Nonlinear Feedback Control

The theory of high-gain observers has been developed for about twenty years. This paper is a brief introduction to high-gain observers in nonlinear feedback control, with emphasis on the peaking phenomenon and the role of control saturation in dealing with it. The paper surveys recent results on the nonlinear separation principle, conditional servo compensators, extended high-gain observers, performance in the presence of measurement noise, sampled-data control, and experimental testbeds.
Tracking directions-of-arrival with invariant subspace updating

Abstract A new method for solving directions-of-arrival (DOA) tracking problems is presented. It is based on a practical method for updating invariant subspaces, introduced by G.W. Stewart. This method is O( L 2 ), where L is the number of array sensors. One advantage gained by using the invariant subspace updating method is the ability to track rapidly changing DOAs. In addition, it is possible to track sources as they appear or disappear in the incoming data. The results are indistinguishable from those obtained from a full eigendecomposition at every step.
Common Beliefs and the Existence of Speculative Trade

Abstract This paper shows that if rationality is not common knowledge, the no-trade theorem of Milgrom and Stokey fails to hold. We adopt Monderer and Samet's notion of common p -belief and show that when traders entertain doubts about the rationality of other traders, arbitrarily large volumes of trade as well as rationality may be common p -belief for a large p . Furthermore, rationality and trade may simultaneously be known to arbitrary large (but finite) degree. Journal of Economic Theory Classification numbers: C70, D82, D84.
Radiative Transfer From a Gray, Absorbing-Emitting, Isothermal Medium in a Conical Enclosure

Simulation numerique du transfert de chaleur par rayonnement ayant lieu dans une enceinte conique, grise et isotherme. Comparaison des resultats obtenus a partir de la technique de Monte Carlo et de la methode d'approximation differentielle. Etude realisee pour differentes epaisseurs optiques et formes coniques
Equatorial Spread F: A Review of Recent Experimental Results

The near space region of the Earth is an excellent laboratory in which to study large scale plasma instabilities. This is particularly true in the equatorial ionosphere where the background conditions are fairly well understood, as opposed to the auroral zone ionosphere for example, where an extremely complex interaction occurs between the ionosphere and the hot plasma at high altitudes. In this paper we review an intense research effort aimed at understanding the large scale disruption of the equatorial F layer which often commences just after sunset, and lasts for most of the night. A very attractive explanation for the phenomena, although one not universally accepted, is that the F layer is unstable to the classic Rayleigh-Taylor condition in which a heavy fluid, the plasma, is supported against gravity by a light “fluid”, the Eartht’s magnetic field. We conclude that a reasonable case has been made for this explanation provided that the concept is extended to include nonlinear Rayleigh-Taylor like bouyancy effects above the F peak where the linear process is stable. Internal gravity waves in neutral atmosphere seem to play an important role in seeding the Rayleigh-Taylor process with large scale finite amplitude perturbations. One of the remarkable features of this phenomena is the nearly simultaneous generation of structure with scale sizes spanning five orders of magnitude. These results may have applications in astrophysical processes where the Rayleigh-Taylor instability is thought to play a role.
Equity Duration, Growth Options, and Asset Pricing

Because much of the value of equity depends on option characteristics of investment projects, it is not feasible to calculate equity duration directly. As a result, recent literature has focused on estimating equity duration empirically. Using twenty–five size and book–to–market portfolios, the author shows the estimates of equity duration are critically dependent on the specification of the regression model used to estimate equity duration.
A REFLECTION FREE BOUNDARY CONDITION FOR PROPAGATION IN UNIFORM FLOW USING MAPPED INFINITE WAVE ENVELOPE ELEMENTS

Variable order mapped infinite wave envelope elements are developed for finite element modeling of acoustic radiation in a uniformly moving medium. These elements are used as a nonreflecting boundary condition for computations on an infinite domain in which a radiating body is immersed in a moving medium which is essentially undisturbed outside of the near field. The mapped elements provide a boundary condition equivalent to element stiffness, mass, and damping matrices appended to an inner standard FEM mesh. A demonstration of the performance of mapped elements as influenced by element order is given in the context of acoustic radiation from a turbofan inlet and exhaust.
Study of the Effect of Hole Clearance and Thread Fit on the Self-Loosening of Threaded Fasteners

This study provides an experimental and theoretical investigation of the effect of hole clearance and thread fit on the self-loosening of tightened threaded fasteners that are subjected to a cyclic transverse service load. An experimental procedure and test setup are developed in order to collect real-time data on the rate of clamp load loss per cycle as well as the loosening rotation of the bolt head. Three levels of hole clearance are investigated; namely, 3%, 6%, and 10% of the bolt nominal diameter. For the commonly used 2A thread fit for a selected bolt size, three classes of the nut thread fit are considered; namely, 1B, 2B, and 3B. A simplified mathematical model is used for the analytical investigation of the effect of the hole clearance and thread fit on threaded fasteners self-loosening. The experimental and theoretical results are presented and discussed.
Medical control of intraocular pressure after cataract surgery

Abstract Purpose: To compare the effectiveness of 2 medications commonly used to prevent intraocular pressure (IOP) elevation in the early period after cataract surgery. Setting: Palo Alto Veterans Affairs Health Care System, Palo Alto, California, USA. Methods: This prospective study comprised 202 eyes of patients scheduled for cataract extraction who agreed to participate. Patients were randomized to receive oral acetazolamide, 500 mg 1 hour preoperatively; oral acetazolamide 500, mg immediately postoperatively; apraclonidine hydrochloride 1%, 2 drops 1 hour preoperatively; or artificial tears (control group). Intraocular pressure was measured preoperatively and 4 to 6 and 24 hours postoperatively. Results: Preoperative IOP was not significantly different among the 4 groups. At 4 to 6 hours postoperatively, only preoperative acetazolamide was significantly more effective than the control medication (P = .038); at 24 hours there were no significant differences among the 4 groups. Postoperative IOP elevation in excess. of 35 mm Hg at 6 or 24 hours decreased significantly in the preoperative . acetazolamide group (3/46 eyes) compared with the control group (14/54 eyes). There was no statistically significant difference in IOP elevation between eyes having extracapsular cataract extraction and those having phacoemulsifioation, independent of treatment group. Conclusion: The results favor preoperative acetazolamide to control postcataract IOP elevation. The method of cataract removal did not affect postoperative IOP elevation.
An Efficient Sensing Localization Algorithm for Free-Form Surface Digitization

We present a divide-and-conquer method that efficiently finds a near-optimal distribution of sensing locations for free-form surface digitization. We formulate a next-best-point problem and transform the uncertainty of a B-spline surface into a higher-dimensional B-spline surface. This technique allows the use of the convex hull and subdivision properties of B-spline surfaces in the divide-and-conquer algorithm. It thus greatly reduces the search time for determining the next best sensing location.
Au(I)-Catalyzed Cycloisomerizations Terminated by sp3 C-H Bond Insertion

The gold(I)-catalyzed cycloisomerization of 1,5-enynes and 1,4-allylallenes to tetracyclododecane and tetracyclotridecane derivatives, respectively, is reported. Complexation of the cationic gold(I) complex to either the alkyne or allene moiety induces an intramolecular addition of the alkene, leading to a gold(I)-stabilized carbenoid intermediate. This intermediate undergoes a formal sp3 C−H insertion to generate the tetracyclic adduct. A series of deuterium labeling experiments showed that the C−H functionalization step proceeds with an inverse kinetic isotope effect.
Jet-medium interactions: Wakes in the QCD medium

We calculate the wake induced in a hot, dense QCD medium by a fast parton in the framework of linear response theory. We discuss two different scenarios: i) a weakly coupled quark gluon plasma (pQGP) described by hardthermal loop (HTL) perturbation theory and ii) a scenario where the plasma has the properties of a quantum liquid. We show that a Mach cone can appear in the second scenario, but not in the first one.
Photocycloaddition-fragmentation route to quinanes: Alternate fragmentation pathways

Abstract We describe here a new type of fragmentation pathway leading to diquinane skeletons, where the normal reactivity of the systems is dramatically altered by a suitably positioned radical stabilizing groups.
A Gibbs sampler for mixed logit analysis of differentiated product markets using aggregate data

In this paper, we offer the Gibbs sampler as an alternative to the GMM estimator developed by Berry, Levinsohn, and Pakes (Econometrica 63(4), 841---890, 1995) in their equilibrium differentiated product market analysis of the automobile industry. We use the GMM objective as the basis for forming a posterior distribution, thereby making use of certain attributes of the GMM approach that reduce the computational cost of conducting posterior inference. The advantages provided by the our Bayesian GMM approach are that it enables us to conduct inference under the exact posterior distribution for the parameters, to estimate moments of functions of interest that are not readily available using GMM, and to capture non-normalities in the parameter distributions. The cost of posterior inference takes the form of additional distributional assumptions and longer computational time. In an illustration within, we find the random coefficients to be only weakly identified by the data. This results in highly non-normal distributions. The GMM estimates hint at this problem, but it can only be fully characterized by the Gibbs sampler.
Holomorphic curves from matrices

Abstract Membranes holomorphically embedded in flat non-compact space are constructed in terms of the degrees of freedom of an infinite collection of 0-branes. To each holomorphic curve we associate infinite-dimensional matrices which are static solutions to the matrix theory equations of motion, and which can be interpreted as the matrix theory representation of the holomorphically embedded membrane. The problem of finding such matrix representations can be phrased as a problem in geometric quantization, where ϵ ∝ lP3/R plays the role of the Planck constant and parametrizes families of solutions. The concept of Bergman projection is used as a basic tool, and a local expansion for the action of the projection in inverse powers of curvature is derived. This expansion is then used to compute the required matrices perturbatively in ϵ. The first two terms in the expansion correspond to the standard geometric quantization result and to the result obtained using the metaplectic correction to geometric quantization.
Elastic and inelastic surface effects on ion penetration and the resulting sputtering and backscattering

Abstract The computer code ITMC (Ion Transport in Materials and Compounds) has been developed to study in detail the transport of charged particles in solid materials and surface related phenomena such as sputtered atoms and backscattered ions. The code is based on Monte Carlo methods to follow the path and the damage produced by the charged particles in three dimensions as they slow down in target materials. Single-element targets as well as alloys with possible different surface and bulk compositions or with layered structures of different materials can be used. Various models developed to calculate the inelastic energy losses in collisions with target electrons can be used in the code. Most known interatomic potentials can also be used to calculate the elastic energy losses. The major advantages of the code are its ability and flexibility to use and compare various models of elastic and inelastic energy losses in any target with different compounds and different surface and bulk composition.
Juvenile decertification: developing a model for classification and prediction

This study considers the impact of data from the Psychopathy Checklist: Youth Version (PCL:YV), the Massachusetts Youth Screening Instrument (MAYSI), and the Youth Level of Service Case Management Inventory (YLS/CMI) on the court’s decision whether to decertify an adolescent defendant back to juvenile court or keep the defendant in criminal court. There are significant positive relationships between certification status and age; number of violent charges; total charges; PCL:YV, YLS/CMI, and MAYSI total scores; and select subscales of the MAYSI and the YLS/CMI. Significant differences are found between those who remained in the adult criminal justice system and those who were decertified to the juvenile justice system for age, YLS/CMI total score, and the Prior and Current Offenses and Dispositions and Personality and Behavior subscales of the YLS/CMI. The combination of PCL:YV total score and select subscales from the MAYSI and YLS/CMI provided the most accurate model for predicting certification status.
Auction Algorithms for Market Equilibrium

In this paper we study algorithms for computing market equilibrium in markets with linear utility functions. The buyers in the market have an initial endowment given by a portfolio of goods. The market equilibrium problem is to compute a price vector that ensures market clearing, i.e., the demand of a positively priced good equals its supply, and given the prices, each buyer maximizes its utility. The problem is of considerable interest in economics. This paper presents a formulation of the market equilibrium problem as a parameterized linear program. We construct a family of duals corrresponding to these parameterized linear programs and show that finding the market equilibrium is the same as finding a linear program from this family of linear programs. The market-clearing conditions arise naturally from complementary slackness conditions. We then define an auction mechanism that computes prices such that approximate market clearing is achieved. The algorithm we obtain outperforms previously known methods.
1-Phenylthio-1-(trimethylsiloxy)cyclopropanes via the sila-Pummerer rearrangement

Abstract This first study of the sila-Pummerer rearrangement in a cyclopropane system reveals that several 1-trimethylsiloxy-1 -(phenylthio)cyclopropanes can be prepared stereoselectively through putative sulfur-stabilized carbocationic intermediates.
ADSORPTION OF MIXED SURFACTANT SYSTEMS.

The mechanism responsible for the existence of an adsorption maximum observed in static experiments gives rise to unusual effects attending the chromatographic movement of surfactant solutions through a porous medium. These effects are identified by studying the transport of a model system consisting of a binary surfactant mixture as it moves through a porous medium. It is shown that surfactant fractionation is likely to be more significant at low concentrations and that fractionation will be more important in the field than in laboratory models. Two other interesting features are observed: (1) the effluent concentration may in some cases exceed that of the inflow; and (2) the effect of rate-controlled transport is to introduce additional surfactant dispersion. (17 refs.) l surfactant dispersion. (17 refs.)
A Probabilistic Approach to Interior Regularity of Fully Nonlinear Degenerate Elliptic Equations in Smooth Domains

We consider the value function of a stochastic optimal control of degenerate diffusion processes in a domain D. We study the smoothness of the value function, under the assumption of the non-degeneracy of the diffusion term along the normal to the boundary and an interior condition weaker than the non-degeneracy of the diffusion term. When the diffusion term, drift term, discount factor, running payoff and terminal payoff are all in the class of \(C^{1,1}(\bar{D})\), the value function turns out to be the unique solution in the class of \(C_{loc}^{1,1}(D)\cap C^{0,1}(\bar{D})\) to the associated degenerate Bellman equation with Dirichlet boundary data. Our approach is probabilistic.
Aggressive surgical management of gallbladder cancer: At what cost?

Background An aggressive operative approach to gallbladder cancer has been advocated because of improved long-term survival, but data on short-term outcomes are lacking. Therefore, the purpose of this study was to analyze the postoperative outcomes of patients undergoing operative management of gallbladder cancer. Methods Data from the American College of Surgeons-National Surgical Quality Improvement Program (2005–2009) were queried for patients with a diagnosis of gallbladder cancer. Outcomes included serious morbidity, overall morbidity, and mortality. Results For the 613 patients identified, the median age was 67 years, and 64% were female. A potentially curative operation was performed in 424 (69%) patients, including cholecystectomy alone (n =150, 35%), partial hepatectomy (n = 249, 59%), and extensive hepatectomy (n = 25, 6%). Overall morbidity rates for these procedures were 21%, 19%, and 28%, respectively. Mortality was greater (P Conclusion Partial hepatectomy is the most common procedure performed for gallbladder cancer and is a safe operation. A small minority of younger, healthier patients undergoes an extensive hepatectomy, but the mortality of this operation is greater. This analysis suggests that patients with gallbladder cancer should be managed at high-volume centers.
Distribution of plasma potential for an MPD thruster.

Propellant injection through electrodes effect on plasma potential distribution in MPD arc thruster
Effects of pairing in the pseudo-SU(3) model

Abstract An extended version of the pseudo-SU(3) model which includes both spin and proton-neutron degrees of freedom is used to study the influence of the pairing interaction on K-band mixing, B(E2) values and quadrupole moments. Using the asymmetric rotor model as a backdrop, specific consequences of a many-particle shell-model based description of these collective properties are demonstrated and fundamental limits of the collective model's approach are investigated. Finally, the pseudo-SU(3) model, including representation mixing induced by pairing, is used to calculate the energies of 140Ce and the results are compared to experimental data and other theories.
OBSERVATIONAL CONSTRAINTS ON THE GENERALIZED CHAPLYGIN GAS

In this paper we study a quintessence cosmological model in which the dark energy component is considered to be the generalized Chaplygin gas and the curvature of the three-geometry is taken into account. Two parameters characterize this sort of fluid: ν and α. We use different astronomical data for restricting these parameters. It is shown that the constraint ν ≲ α agrees well enough with the astronomical observations.
Structural Insight into the Aromatic Amino Acid Hydroxylases and Their Disease-Related Mutant Forms.

The mammalian aromatic amino acid hydroxylases (phenylalanine, tyrosine, and tryptophan hydroxylase (PheOH, TyrOH, TrpOH, respectively)) are functionally and structurally closely related enzymes (e.g. 65% sequence identity and 80% sequence homology in the catalytic domains)1 (Figure 1). This family of enzymes shares a common catalytic mechanism, in which dioxygen is used by an active site containing a single, reduced iron atom to hydroxylate an unactivated aromatic substrate (i.e., monooxygenase activity), concomitant with a two-electron oxidation of tetrahydropterin cofactor to its quinonoid dihydropterin form (Figure 2).2 The enzymes play an important role in mammalian metabolism: PheOH initiates the catabolism/detoxification of high levels of phenylalanine, while TyrOH and TrpOH catalyze the rate-limiting steps in the biosynthesis of the neurotransmitters/hormones dopamine/noradrenaline/adrenaline and serotonin, respectively. In 1959, Kaufman3 related a deficiency in hPheOH to the genetic disease phenylketonuria (PKU), and more recently a deficiency in hTyrOH has been related to the genetic disease L-DOPA responsive dystonia4 and juvenile parkinsonism.5 Current research is close to linking TyrOH with bipolar affective disorder6 and studying the relationship between DNA polymorphism of the TyrOH gene and schizophrenia7 (see section 4). Reduced biosynthesis of L-DOPA by TyrOH as a result of progressive degeneration of dopaminergic neurons in the nigrostriatal pathway is characteristic of idiopathic parkinsonism (Parkinson’s disease), and evidence has recently been presented that the TyrOH enzyme system itself may contribute to the oxidative stress considered to be responsible for the neurodegeneration.8 While the enzymes operate on different amino acid substrates, the similarity of substrate structure is apparent, and recent data have provided important sequence and mechanistic links between the different hydroxylases. In solution, the aromatic amino acid hydroxylases form homotetramers with molecular mass ranging from 204 to 217 kDa. Sequence homologies, sitedirected mutagenesis, and partial proteolysis experiments have demonstrated that these enzymes are composed of an N-terminal region (PheOH 1-142; TyrOH 1-155; TrpOH 1-177) with regulatory properties and a C-terminal region (PheOH 143-452; TyrOH 156-498; TrpOH 178-445) known to be * Corresponding author. 2137 Chem. Rev. 1999, 99, 2137−2160
Earnings announcements, trading volume, and price discovery: evidence from dual class firms

This paper investigates price discovery between control shares (the superior voting class) and public shares (the inferior voting class) issued by 62 dual-class firms around 148 quarterly earnings announcements from January 2002 to June 2008. We document substantial informed trading in both control and public shares. The average price discovery of control shares is 46.6 % for positive events and 40.5 % for negative events during the event periods. In addition, before the earnings announcements, abnormal trading volume and price discovery increase significantly in control shares relative to public shares. We find price discovery of control shares increases with relative volume of control shares to public shares and relative bid-ask spread but decreases with relative institutional ownership and relative volatility. Our results suggest that publicly traded superior voting class contributes to price discovery substantially, especially before earnings announcements when the information asymmetry is high. The listing of control shares not only enhances price efficiency, but also provides opportunities for outside sophisticated investors to get voting rights and engage in monitoring. Our study sheds new light on the issues of price discovery and corporate governance of dual-class firms.
Synthesis and characterization of chiral bimetallic complexes bearing hard and soft Lewis acidic sites

Abstract A new class of optically active heterobimetallic complexes is described. The complexes L*MCl 2 (M = Pt(II), Pd(II), L* = C 2 -symmetric boron-containing bisphosphine ligand) and [Rh(cod)(L*)]ClO 4 (cod = η 2 ,η 2 -1,5-cyclooctadiene) were synthesized as possible templates for asymmetric catalytic reactions that involve substrate precoordination to a Lewis acidic site remote from the transition metal reaction site. Primary amines were found to bind reversibly via a B-N interaction to the free ligands L*. 1 H NMR measurements revealed that the binding constant of representative primary amines to L* could be tuned through variation of the electronic properties of the substituents covalently bound to boron.
Deer Creek Farms: Tradition into the Future

The Deer Creek Farms case study illustrates a family farm operation that is trying to identify how to transition the business to include the next generation. The family is currently growing corn, soybeans, and contract hogs. The family is faced with decisions to expand production in one or more of the current enterprises, exit out of one or more of the current enterprises, or diversify into additional enterprises. Each member of the family is given the task of proposing their vision of the farm's future. The examples illustrated through the Deer Creek Farms case study will assist agricultural producers as they monitor, identify, and manage strategic risk on their farms.
Why Do Managers Undertake Acquisitions? An Analysis of Internal and External Rewards for Acquisitiveness

We study the effect of a firm's acquisitions on the subsequent career of its chief executive officer (CEO) by examining a sample of executives who undertook large acquisitions between 1986 and 1988. We find that acquirers do not have significantly different compensation growth from executives who did not undertake acquisitions. Further, we find the effect of acquisitions on compensation does not depend on whether the acquisition increased shareholder weatth, nor on whether the acquisition was diversifying. We do find a benefit to acquisitions, however, because CEOs who completed acquisitions are significantly more likely to gain outside directorships than those who did not complete acquisitions. Our results do not support the argument that CEOs have an incentive to pursue acquisitions in order to increase their own compensation, but lend support to the argument that CEOs have an incentive to pursue acquisitions to increase their prestige and standing in the business community.
Secret Key Generation from Sparse Wireless Channels: Ergodic Capacity and Secrecy Outage

This paper investigates generation of a secret key from a reciprocal wireless channel. In particular we consider wireless channels that exhibit sparse structure in the wideband regime and study the impact of sparsity on the secret key capacity. We explore this problem in two steps. First, we study key generation from a state-dependent discrete memoryless multiple source. The state of the source captures the effect of channel sparsity. Secondly, we consider a wireless channel model that captures channel sparsity and correlation between the legitimate users' channel and the eavesdropper's channel. Such dependency can significantly reduce the secret key capacity. According to system delay requirements, two performance measures are considered: (i) ergodic secret key capacity and (ii) outage probability. We show that in the wideband regime when a white sounding sequence is adopted, a sparser channel can achieve a higher ergodic secret key rate than a richer channel can. For outage performance, we show that if the users generate secret keys at a fraction of the ergodic capacity, the outage probability will decay exponentially in signal bandwidth. Moreover, a larger exponent is achieved by a richer channel.
Arachnophobia: A Case on Impairment and Accounting Ethics

ABSTRACT: This case requires students to apply accounting and ethical decision making within the context of a potential land impairment decision. Students are required to research the relevant professional literature and provide appropriate FASB codification references and IAS cites as they investigate the significant uncertainties that frequently are associated with valuation and impairment analyses. Students also are required to evaluate the ethical implications of the decisions that could be made regarding the necessity of impairment. The case provides an opportunity for students to extend their research and financial accounting abilities, to consider the consequences associated with a set of potentially reasonable accounting alternatives, and to begin to appreciate how the significant uncertainties that are present in many accounting and auditing situations require consistent technical and ethical decision making. The case could be used in Intermediate Accounting I, as well as in undergraduate and gra...
Normal state resistance and low temperature magnetoresistance of superconducting cables for accelerator magnets

Resistance measurements which are routinely made on superconducting wires and cables for accelerator magnets can provide an accurate measure of the copper-to-superconductor ratio. Compared to the etch and weight technique, a resistance specification for Cu/Sc is preferable for monitoring of this parameter during wire and cable production. Results shown here indicate that by using the 4 K magnetoresistance data of bulk copper and the size effect formula for the resistivity enhancement of copper, the measured residual resistance ratio can be used to estimate the resistance at high fields. >