cssi/SciSciGPT-SciSciNet huggingface dataset:
X-RAYS IN THE ORION NEBULA CLUSTER: CONSTRAINTS ON THE ORIGINS OF MAGNETIC ACTIVITY IN PRE-MAIN-SEQUENCE STARS

A recent observation of the Orion Nebula Cluster with the ACIS instrument on board the Chandra X-Ray Observatory detected 1075 sources, 525 of which are pre-main-sequence (PMS) stars with measured bulk properties such as bolometric luminosities, masses, ages, and disk indicators. Nearly half of these stars have photometrically measured rotational periods. This provides a uniquely large and well-defined sample to study the dependence of magnetic activity on bulk properties for stars descending the Hayashi tracks. The following results are obtained: (1) X-ray luminosities Lt in the 0.5-8 keV band are strongly correlated with bolometric luminosity, with average ratio log L_t/L_(bol) = -3.8 for stars with masses 0.7 < M < 2 M_☉, an order of magnitude below the main-sequence saturation level; (2) the X-ray emission drops rapidly below this level in some stars with 2 < M < 3 M_☉; (3) the presence or absence of infrared circumstellar disks has no apparent relation to X-ray levels; and (4) X-ray luminosities exhibit a slight rise as rotational periods increase from 0.4 to 20 days. This last finding stands in dramatic contrast to the strong decline of X-ray emission with increasing period seen in main-sequence stars. The absence of a strong X-ray/rotation relationship in PMS stars, and particularly the high X-ray values seen in some very slowly rotating stars, is a clear indication that the mechanisms of magnetic field generation differ from those operating in main-sequence stars. The most promising possibility is a turbulent dynamo distributed throughout the deep convection zone, but other models, such as α-Ω dynamo with "supersaturation" or relic core fields, are not immediately excluded. The drop in magnetic activity in intermediate-mass stars may reflect the presence of a significant radiative core. The evidence does not support X-ray production in large-scale star-disk magnetic fields in T Tauri stars.
Formamidine anions in synthesis. The one-carbon homologation of aldehydes and ketones to nitriles

Abstract Treatment of various carbonyl compounds with the carbanion of the 2-trimethylsilymethyl formamidine 2 gives the enamidine 3 which is readily transformed into the homologated nitriles 6.
On the thermodynamics of hot hadronic matter

Abstract The equation of state of hot hadronic matter is obtained, by taking into account the contribution of the massive states, with the help of the resonance spectrum τ ( m ) ∼ m 3 justified by the authors in previous papers. This equation of state is in agreement with that provided by the low-temperature expansion for the pion interacting gas. The formulas for the temperature dependence of the non-strange and strange quark condensates are derived by taking into account the contribution of the massive resonances. The critical temperature of the chiral symmetry restoration transition is established to be 190 MeV if only meson resonances are considered, and 180 MeV if both meson and baryon resonances are taken into account. The phase transition of chiral symmetry restoration is modelled by the restriction of the number of the effective degrees of freedom in the hadron phase to that of the microscopic degrees of freedom in the quark-gluon phase, through the corresponding truncation of the hadronic resonance spectrum, and the decrease of the effective hadron masses with temperature predicted by Brown and Rho. The results are in agreement with lattice gauge data and show a smooth crossover in the thermodynamic variables in a temperature range ∼ 50 MeV.
Coordinates for Mapping the Distribution of Magnetically Trapped Particles

Dipole representations of the earth's magnetic field have been found to have insufficient accuracy for the study of magnetically trapped particles. A coordinate system consisting of the magnitude of the magnetic field B, and the integral invariant I has been found to adequately organize, measurements made at different geographic locations. It is shown in the present paper, that a parameter L = f(B,I) can be defined which retains most of the desirable properties of I and which has the additional property of organizing measurements along lines of force. Since the parameter L is the analog of a physical distance in a dipole field (the equatorial radius of a magnetic shell), it is usually found to present fewer conceptual difficulties than the integral invariant I.
Simulating the Formation of Molecular Clouds. II. Rapid Formation from Turbulent Initial Conditions

In this paper we present results from a large set of numerical simulations that demonstrate that H2 formation occurs rapidly in turbulent gas. Starting with purely atomic hydrogen, large quantities of molecular hydrogen can be produced on timescales of 1-2 Myr, given turbulent velocity dispersions and magnetic field strengths consistent with observations. Moreover, as our simulations underestimate the effectiveness of H2 self-shielding and dust absorption, we can be confident that the molecular fractions that we compute are strong lower limits on the true values. The formation of large quantities of molecular gas on the timescale required by rapid cloud formation models therefore appears to be entirely plausible. We also investigate the density and temperature distributions of gas in our model clouds. We show that the density probability distribution function is approximately lognormal, with a dispersion that agrees well with the prediction of Padoan and coworkers. The temperature distribution is similar to that of a polytrope, with an effective polytropic index γeff 0.8, although at low gas densities, the scatter of the actual gas temperature around this mean value is considerable, and the polytropic approximation does not capture the full range of behavior of the gas.
Coherent population transfer of ground-state atoms into Rydberg states

The technique of stimulated Raman adiabatic passage (STIRAP) is used to excite laser-cooled rubidium atoms from the $^{85}\mathrm{Rb}\phantom{\rule{0.3em}{0ex}}5{S}_{1∕2}$ ground state to the $44{D}_{5∕2}$ Rydberg state through the $5{P}_{3∕2}$ state. The utilized double-STIRAP scheme allows for an accurate determination of the absolute excitation efficiency. Experimental data are compared with results of a detailed theoretical model, and good agreement is found. It is concluded that at the center of the excitation region an excitation efficiency of 70% is achieved.
The rates and spatial patterns of annual riverbank erosion revealed through terrestrial laser‐scanner surveys of the South River, Virginia

Between a.d. 2006 and 2008, we completed annual surveys of two mercury-contaminated eroding banks, one forested and the other grass covered, along the gravel-bed, bedrock South River in Virginia. Gridded digital terrain models with a resolution of 0·05 m were created from bank topography data collected using a terrestrial laser scanner. Model comparisons indicate that the forested bank retreated nearly 1 m around two leaning trees, while elsewhere the extent of bank retreat was negligible. On the grassy bank, retreat was controlled by the creation of small overhanging clumps of turf at the top of the bank, their occasional failure, and the ultimate removal of failed debris from the bank toe. Partial autocorrelation analysis of vertically integrated bank retreat demonstrates that bank profile erosion is virtually uncorrelated at horizontal distances greater than about 1 m on both banks, a length scale of approximately half the bank height. This extensive streamwise variability suggests that widely spaced profile data cannot adequately represent bank erosion at these sites. Additional analysis of our comprehensive spatial data also indicates that traditional bank profile surveys with any spacing greater than 1 m would result in measurement errors exceeding 10%, an important conclusion for assessing annual rates of mercury loading into the South River from bank erosion. Our results suggest that three-dimensional gridded bare-earth models of bank topography may be required to accurately measure annual bank retreat in similar river systems. Copyright © 2010 John Wiley & Sons, Ltd.
Birational Equivalences of Vortex Moduli

Abstract We construct a finite-dimensional Kahler manifold with a holomorphic, symplectic circle action whose symplectic reduced spaces may be identified with the τ-vortex moduli spaces (or τ-stable pairs). The Morse theory of the circle action induces natural birational maps between the reduced spaces for different values of τ which in the case of rank two bundles can be canonically resolved in a sequence of blow-ups and blow-downs.
Supercharacter formulas for pattern groups

C. Andre and N. Yan introduced the idea of a supercharacter theory to give a tractable substitute for character theory in wild groups such as the unipotent uppertriangular group U n (F q ). In this theory superclasses are certain unions of conjugacy classes, and supercharacters are a set of characters which are constant on superclasses. This paper gives a character formula for a supercharacter evaluated at a superclass for pattern groups and more generally for algebra groups.
Integral points on subvarieties of semiabelian varieties, II

This paper proves a finiteness result for families of integral points on a semiabelian variety minus a divisor, generalizing the corresponding result of Faltings for abelian varieties. Combined with the main theorem of the first part of this paper, this gives a finiteness statement for integral points on a closed subvariety of a semiabelian variety, minus a divisor. In addition, the last two sections generalize some standard results on closed subvarieties of semiabelian varieties to the context of closed subvarieties minus divisors.
Observing the symmetry of attractors

Abstract We show how the symmetry of attractors of equivariant dynamical systems can be observed by equivariant projections of the phase space. Equivariant projections have long been used, but they can give misleading results if used improperly and have been considered untrustworthy. We find conditions under which an equivariant projection generically shows the correct symmetry of the attractor.
Shielding effectiveness of 'pigtail' connections

The shielding effectiveness of a 'pigtail' connection between a coaxial transmission line and a ground plane is treated rigorously by the method of moments, as a function of the type and number of pigtails and frequency. Numerical results show that the type of pigtail connection is crucial with regard to radiation and shielding effectiveness, even though the pigtail itself does not radiate significantly. All pigtails are not equal, even though they can be short electrically. A short pigtail is significantly better than a longer one. A long pigtail connection can actually enhance radiation. Finally, multiple pigtails yield significant improvement over the single pigtail only for short pigtails. Numerical and experimental results are compared and found to be in good agreement. >
Redshift-space distortions with the halo occupation distribution – II. Analytic model

We present an analytic model for the galaxy two-point correlation function in redshift space. The cosmological parameters of the model are the matter density Ω m , power spectrum normalization σ 8 , and velocity bias of galaxies α v , circumventing the linear theory distortion parameter β and eliminating nuisance parameters for non-linearities. The mode] is constructed within the framework of the halo occupation distribution (HOD), which quantifies galaxy bias on linear and non-linear scales. We model one-halo pairwise velocities by assuming that satellite galaxy velocities follow a Gaussian distribution with dispersion proportional to the virial dispersion of the host halo. Two-halo velocity statistics are a combination of virial motions and host halo motions. The velocity distribution function (DF) of halo pairs is a complex function with skewness and kurtosis that vary substantially with scale. Using a series of collisionless N-body simulations, we demonstrate that the shape of the velocity DF is determined primarily by the distribution of local densities around a halo pair, and at fixed density the velocity DF is close to Gaussian and nearly independent of halo mass. We calibrate a model for the conditional probability function of densities around halo pairs on these simulations. With this model, the full shape of the halo velocity DF can be accurately calculated as a function of halo mass, radial separation, angle and cosmology. The HOD approach to redshift-space distortions utilizes clustering data from linear to non-linear scales to break the standard degeneracies inherent in previous models of redshift-space clustering. The parameters of the occupation function are well constrained by real-space clustering alone, separating constraints on bias and cosmology. We demonstrate the ability of the model to separately constrain Ω m , σ 8 and α v in models that are constructed to have the same value of β at large scales as well as the same finger-of-god distortions at small scales.
Comparison between EVM and RSM turbulence models in predicting flow and heat transfer in rib-roughened channels

A 3D analysis of two-equation eddy viscosity (EVMs) and Reynolds stress (RSM) turbulence models and their application to solve flow and heat transfer in rotating rib-roughened internal cooling channels is the main focus of this study. The flow in these channels is affected by ribs, rotation, buoyancy, bends and boundary conditions. The EVMs considered are the standard k–ϵ model of Launder and Spalding [1], the renormalization group k–ϵ model of Yakhot and Orszag [2], the realizable k–ϵ model of Shih et al. [3], the standard k–ω model of Wilcox [4] and the shear–stress transport (SST) k–ω model of Menter [5]. The viscosity-affected near-wall region is resolved by enhanced near-wall treatment using combined two-layer model with enhanced wall functions. The results for both stationary and rotating channels showed the advantages of Reynolds stress model (RSM), Gibson and Launder [6], Launder [7] and Launder et al. [8] in predicting the flow field and heat transfer compared to two-equation EVMs that need corre...
LONG STRINGS IN TWO-DIMENSIONAL STRING THEORY AND NON-SINGLETS IN THE MATRIX MODEL

We consider two-dimensional string backgrounds. We discuss the physics of long strings that come from infinity. These are related to non-singlets in the dual matrix model description.
Generation and tandem reactions of 1-alkenyl-1,1-heterobimetallics: practical and versatile reagents for organic synthesis.

A practical and straightforward method for generation of versatile 1-alkenyl-1,1-heterobimetallic intermediates and their application to construction of functionalized building blocks are disclosed. Beginning with readily available air-stable 1-alkynyl-1-boronate esters, hydroboration with dicyclohexylborane generates 1-alkenyl-1,1-diboro species. In situ transmetallation with dialkylzinc reagents furnishes 1-alkenyl-1,1-heterobimetallic intermediates. Direct treatment with aldehydes followed by workup allows isolation of B(pin)-substituted allylic alcohols in 70−95% yield. The B(pin)-substituted allylic alcohols react with NBS to afford (E)-α,β-unsaturated aldehydes in 51−77% yield via a semipinacol-type rearrangement. In situ treatment of 1-alkenyl-1,1-heterobimetallic intermediates with aldehydes followed by TBHP oxidation enables the preparation of α-hydroxy ketones. Under optimized conditions, addition of 1-alkenyl-1,1-heterobimetallic intermediates to a variety of protected α- and β-hydroxy aldehyde...
Equilibrium business cycles with idle resources and variable capacity utilization

A real business cycle economy is studied in which some capital is idle each period and the fraction of capital left idle varies in response to technology shocks. Previous equilibrium business cycle models have the characteristic that the entire stock of capital is used for production in each period. Our objective is to determine whether incorporating idle resources, something regularly observed in actual economies, significantly affects the cyclical properties of the model and hence changes our views about the importance of technology shocks for aggregate fluctuations. In our analysis we do not assume an aggregate production function, but instead model production as taking place at individual plants that are subject to idiosyncratic technology shocks. Each period the plant manager must choose whether to operate the plant or to let the plant remain idle. We find that the cyclical properties of this model are surprisingly similar to those of a standard real business cycle economy. One difference is that the model displays variation in factor shares while the standard models does not.
The Effect of Finasteride on the Prostate Gland in Men With Elevated Serum Prostate-Specific Antigen Levels

Prostate cancer is a disease associated with androgens. It has been hypothesized that reducing the conversion of testosterone (T) to dihydrotestosterone (DHT) in the prostate by the use of the drug finasteride, a 5alpha-reductase inhibitor, will reduce the incidence of prostate cancer. We investigated the chemopreventive potential of finasteride by evaluating its effect on the prostate gland of men with elevated serum prostate-specific antigen (PSA). Fifty-two men with elevated PSA and prostate sextant biopsies negative for cancer were randomized to receive finasteride 5 mg day(-1) (27 patients) or no medication (25 patients) for 12 months and were rebiopsied at 12 months. The biopsies were evaluated for the presence of cancer, the proportion of glandular and hyperplastic tissue, and the presence of high-grade prostatic intraepithelial neoplasia (PIN). Epithelial proliferation was assessed in the prestudy and 12-month biopsies by immunohistochemistry using antibody to proliferating cell nuclear antigen (PCNA). Serum blood samples were drawn at baseline and after 1, 3, 6 and 12 months of study. In the control group, serum levels of PSA and T were unchanged throughout the 12 months. In the finasteride group, PSA decreased 48% (P < 0.001), DHT decreased 67% (P < 0.001) and T increased 21% (P < 0.001). Histological evaluation of prestudy and 12-month biopsy specimens revealed that the finasteride group had a 30% reduction in the percentage of hyperplastic epithelial tissue (P = 0.002), although this decrease was not statistically significantly different between the finasteride and control groups (P = 0.11). In patients with PIN on prestudy biopsy, no change occurred in the PIN lesions with finasteride treatment. Finasteride also had no effect on the proliferation index of prostatic epithelial cells. Of the 27 patients treated with finasteride, eight (30%) had adenocarcinoma of the prostate detected on the 12-month biopsy, compared with one (4%) of the control patients (P = 0.025). In the treatment group, six cancers occurred in the eight patients with PIN on the prestudy biopsy; in the observation group no cancers were detected in the five patients with PIN on the prestudy biopsy (P = 0.021). Two cancers occurred in the 19 men in the treatment group with no evidence of PIN on the prestudy biopsy, compared with one cancer in the 20 men in the observation group with no evidence of PIN on the prestudy biopsy (P = 0.60). This study, using a novel model for evaluating short-term efficacy of chemopreventive or therapeutic agents in men at high risk of prostate cancer, provides little evidence that finasteride is an effective chemopreventive agent for prostate cancer in men with elevated PSA.
Stacks and D-brane bundles

In this paper we describe explicitly how the twisted “bundles” on a D-brane worldvolume in the presence of a nontrivial B-field, can be understood in terms of sheaves on stacks. We also take this opportunity to provide the physics community with a readable introduction to stacks and generalized spaces.
Numerical evolution of Brill waves

We report a numerical evolution of axisymmetric Brill waves. The numerical algorithm has new features, including (i) a method for keeping the metric regular on the axis and (ii) the use of coordinates that bring spatial infinity to the edge of the computational grid. The dependence of the evolved metric on both the amplitude and shape of the initial data is found.
Recursive properties of isomorphism types

For Γ a revursively enumerable set of formulae, a structure U on a recursive universe is said to be “Γ-recursively enumerable” if the satisfaction predicate restricted to Γ is recursively enumerable (equivalently, if the formulae of Γ uniformulae of Γ uniformly denote recursively enumerable relations on U).For recursively enumerable sets Γ1 ⊆ Γ2 of formulae we shall, under certain conditions, characterize structures U with the following properties.1) Every isomorphism form U to a Γ1-recursively enumerable structure is a recursive isomorphism.2) Every Γ1-recursively enumerable structure isomorphic to U is recursively isomorphic to U.3) Every Γ1-recursively enumerable structure isomorphic to U is Γ2-recursively enumerable.
Recent Developments in Non-Local Optics

In this paper a brief account is given of results of some recent investigations of four classes of effects due to non-locality (or spatial dispersion) upon optical phenomena in bounded solids. These are: Resonant Inelastic (Brillouin or Raman) Scattering; Transient Reflectivity; Wave Propagation and Additional Boundary Conditions in Gyrotropic Media; Lateral Beam Shift — Goos Hanchen Effect.
Management of urinary bladder injuries in laparoscopic assisted vaginal hysterectomy.

Background. To illustrate our experience and evolution in management of urinary bladder injury in laparoscopically assisted vaginal hysterectomy.Methods. Four hundred and twenty-two women underwent laparoscopically assisted vaginal hysterestomy with or without adnexectomy during the period March 1991-September 1994. The indicators for hysterectomy included adenomyosis myoma uteri, intractable menorrhagia, endometriosis and severe pelvic adhesion. There are six cases of urinary bladder injuries resulting from our 422 cases of laparoscopically assisted vaginal hysterectomy.Results. The first two cases of urinary bladder injuries were repaired through exploratory laparotomy. The third case was repaired through laparoscopic intracorporeal suture. The technique of the automatic linear stapler through laparoscopy was used in case 4. The last two cases were repaired vaginally. All these patients recovered well after primary repair with an indwelling catheter for five to seven days regardless of the method of rep...
Regularity of CR mappings between algebraic hypersurfaces

We prove that if $M$ and $M'$ are algebraic hypersurfaces in $ C^ N$, i.e. both defined by the vanishing of real polynomials, then any sufficiently smooth CR mapping with Jacobian not identically zero extends holomorphically provided the hypersurfaces are holomorphically nondegenerate . Conversely, we prove that holomorphic nondegeneracy is necessary for this property of CR mappings to hold. For the case of unequal dimensions, we also prove that if $M$ is an algebraic hypersurface in $ C^N$ which does not contain any complex variety of positive codimension and $M'$ is the sphere in $ C^{N+1 }$ , then extendability holds for all CR mappings with certain minimal a priori regularity. Theorem A. Let $M$ and $M'$ be two algebraic hypersurfaces in $C^N$ and assume that $M$ is connected and holomorphically nondegenerate. If $H$ is a smooth CR mapping from $M$ to $M'$ with $ Jac H \not\equiv 0$, where $Jac H$ is the Jacobian determinant of $H$, then $H$ extends holomorphically in an open neighborhood of $M$ in $ C^N$. A recent example given by Ebenfelt shows that the conclusion of Theorem A need not hold if $M$ is real analytic, but not algebraic. Theorem B. Let $M$ be a connected real analytic hypersurface in $C^N$ which is holomorphically degenerate at some point $p_1$. Let $p_0 \in M$ and suppose there exists a germ at $p_0$ of a smooth CR function on $M$ which does not extend holomorphically to any full neighborhood of $p_0$ in $C^N$. Then there exists a germ at $p_0$ of a smooth CR diffeomorphism from $M$ into itself, fixing $p_0$, which does not extend holomorphically to any neighborhood of $p_0$ in $C^N$. Theorem C. Let $M\subset C^N$ be an algebraic hypersurface. Assume that there is no nontrivial complex analytic variety contained in $M$ through $p_0 \in M$, and let $m=m_{p_0}$ be the D'Angelo type. If $H: M \to S^{2N+1}\subset C^{N+1}$ is a CR map of class $C^m$, where $S^{2N+1}$ denotes the boundary of the unit ball in $C^{N+1 }$, then $H$ admits a holomorphic extension in a neighborhood of $p_0$.
Shortest Path Problems on a Polyhedral Surface

We describe algorithms to compute edge sequences, a shortest path map, and the Frechet distance for a convex polyhedral surface. Distances on the surface are measured by the length of a Euclidean shortest path. We describe how the star unfolding changes as a source point slides continuously along an edge of the convex polyhedral surface. We describe alternative algorithms to the edge sequence algorithm of Agarwal et al. (SIAM J. Comput. 26(6):1689–1713, 1997) for a convex polyhedral surface. Our approach uses persistent trees, star unfoldings, and kinetic Voronoi diagrams. We also show that the core of the star unfolding can overlap itself when the polyhedral surface is non-convex.
PERTURBATIVE QCD AT HIGH ENERGY COLLIDERS

Selected applications of perturbative Quantum chromodynamics (QCD) to predictions of the Standard Model for processes at high energy colliders are reviewed with emphasis on past successes and future problems.
Time–Space Constrained Codes for Phase-Change Memories

Phase-change memory (PCM) is a promising nonvolatile solid-state memory technology. A PCM cell stores data by using its amorphous and crystalline states. The cell changes between these two states using high temperature. However, since the cells are sensitive to high temperature, it is important, when programming cells (i.e., changing cell levels), to balance the heat both in time and in space. In this paper, we study the time-space constraint for PCM, which was originally proposed by Jiang and coworkers. A code is called an (α, β, p)- constrained code if for any α consecutive rewrites and for any segment of β contiguous cells, the total rewrite cost of the β cells over those α rewrites is at most p. Here, the cells are binary and the rewrite cost is defined to be the Hamming distance between the current and next memory states. First, we show a general upper bound on the achievable rate of these codes which extends the results of Jiang and coworkers. Then, we generalize their construction for (α ≥ 1, β = 1, p = 1)-constrained codes and show another construction for (α = 1, β ≥ 1, p ≥ 1)-constrained codes. Finally, we show that these two constructions can be used to construct codes for all values of α, β, and p.
The spectroscopy, dynamics, and electronic structure of pyrenyl–dU nucleosides: P+/dU− charge transfer state photophysics

Abstract Various spectroscopies including UV–vis absorbance, emission, and emission quantum yield are combined with a variety of kinetics measurements including time resolved emission and nanosecond, picosecond, and femtosecond transient absorbance (TA) to systematize the P +/dU − charge transfer (CT) state dynamics of a variety of pyrenyl–dU nucleoside conjugates in several solvents of varying polarity. These results are then analyzed further by means of electronic structure computations in vacuum and using two different solvent models. Finally, the excess electron dynamics of a number of DNA duplex structures substituted with two different pyrenyl–dU nucleosides and 5-XdU, where X=Br or F, electron traps are discussed in terms of achieving high yields of long-lived photoinduced CT products in DNA.
An Approximate Solution to Radiative Transfer in Two-Dimensional Rectangular Enclosures

The application of a new approximate technique for treating radiative transfer in absorbing, emitting, linear-anisotropic scattering, two-dimensional rectangular enclosures is presented. In its development, the discontinuous nature of the radiation intensity, stability of the iterative solution procedure and selection of quadrature points have been addressed. By using this approach, effects of nonuniform and spectrally dependent properties, anisotropic scattering, and reflecting surfaces can be handled effectively. Furthermore, the spatial discretization can be formed without consideration to the chosen discrete directions, permitting a complete compatibility with the discretization of the conservation equations of mass, momentum and energy. The effects of wall emission, gray-diffuse surfaces, and internal emission are considered for comparison with results available in the literature. The computed numerical results are in excellent agreement with those obtained by other numerical approaches.
Finite-Time Destruction of Entanglement and Non-Locality by Environmental Influences

Entanglement and non-locality are non-classical global characteristics of quantum states important to the foundations of quantum mechanics. Recent investigations have shown that environmental noise, even when it is entirely local in influence, can destroy both of these properties in finite time despite giving rise to full quantum state decoherence only in the infinite time limit. These investigations, which have been carried out in a range of theoretical and experimental situations, are reviewed here.
AN EMPIRICAL STUDY OF HIERARCHICAL DIVISION FOR MESH-STRUCTURED NETWORKS

A parallel/distributed system consists of a collection of processes, which are distributed over a network of processors, and work in a cooperative manner to fulfill various tasks. A hierarchical ap...
Quadratic mixed finite element approximations of the Monge---Ampère equation in 2D

We give error estimates for a mixed finite element approximation of the two-dimensional elliptic Monge---Ampere equation with the unknowns approximated by Lagrange finite elements of degree two. The variables in the formulation are the scalar variable and the Hessian matrix.
Boundary rigidity and holography

We review boundary rigidity theorems assessing that, under appropriate conditions, riemannian manifolds with the same spectrum of boundary geodesics are isometric. We show how to apply these theorems to the problem of reconstructing a d+1 dimensional, negative curvature space-time from boundary data associated to two-point functions of high-dimension local operators in a conformal field theory. We also show simple, physically relevant examples of negative-curvature spaces that fail to satisfy in a subtle way some of the assumptions of rigidity theorems. In those examples, we explicitly show that the spectrum of boundary geodesics is not sufficient to reconstruct the metric in the bulk. We also survey other reconstruction procedures and comment on their possible implementation in the context of the holographic AdS/CFT duality.
Constrained signaling for welfare and revenue maximization

We consider auction settings where the seller is constrained in the amount and nature of information he may reveal about the good being sold. This is encountered, for example, in online advertising auctions, where communicating precise details of every viewer to interested advertisers is impractical, costly, and possibly socially undesirable. We initiate the study of constrained signaling in such settings, where a seller must choose which information to reveal subject to exogenous constraints on the signaling policy. We consider a seller employing the second-price auction, and present algorithms and hardness results for approximating the welfare and revenue maximizing signaling policies under a variety of constraints.
Antiemetic prescribing practices using a computerized physician order entry system

Purpose Adherence to guideline-consistent chemotherapy-induced nausea and vomiting (CINV) prophylaxis is suboptimal. The primary aim of this study was to evaluate the magnitude of compliance to institutional guideline-directed antiemetic prophylaxis using a computerized physician order entry system at a single tertiary care institution. A nurse survey was also performed to evaluate how oncology practices, within a cooperative group, managed clinician orders for the prevention of CINV.
The Canadian oil sands industry under carbon constraints

Abstract We investigate the impact of climate policies on Canada’s oil sands industry, the largest of its kind in the world. Deriving petroleum products such as gasoline and diesel from oils sands involves significant amounts of energy, and that contributes to a high level of CO2 emissions. We apply the MIT Emissions Prediction and Policy Analysis (EPPA) model, a computable general equilibrium model of the world economy, augmented to include detail on the oil sands production processes, including the possibility of carbon capture and storage (CCS). We find: (1) without climate policy, annual Canadian bitumen production increases almost 4-fold from 2010 to 2050; (2) with climate policies implemented in developed countries, Canadian bitumen production drops by 32% to 68% from the reference 4-fold increase, depending on the viability of large-scale CCS implementation, and bitumen upgrading capacity moves to the developing countries; (3) with climate policies implemented worldwide, the Canadian bitumen production is significantly reduced even with CCS technology, which lowers CO2 emissions at an added cost. This is mainly because upgrading bitumen abroad is no longer economic with the global climate policies.
Application of fracture mechanics in the design and operation of PWRs in France

Fracture mechanics techniques are used to evaluate the risks associated with material aging, the occurrence of fabrication defects or stress corrosion cracks, and to determine the margins with respect to fast fracture resulting from the design and manufacturing practices. Important programs are underway to improve the accuracy and domain of validity of the fracture mechanics methods.
Tandem cyclization of alkynes via rhodium alkynyl and alkenylidene catalysis.

A rhodium(I)-catalyzed tandem cyclization of alkynes has been developed. The reaction allows for multiple bond formations to occur at both the α- and β-positions of alkynes under mild conditions to yield a variety of fused ring systems as the products. In the presence of triethylamine and the complex derived from [Rh(COD)Cl]2 and P(4-F-C6H4)3, a terminal alkyne is converted to a rhodium alkynyl species which reacts with a tethered alkyl halide at the β-position to provide a β,β-disubstituted alkenylidene complex. The rhodium alkenylidene species then undergoes additional ring closures with a range of pendent functional groups such as alkene, hydroxyl, and phenyl groups through [2 + 2] cycloaddition, nucleophilic addition, and 6π-electrocyclization processes, respectively.
Derivation of a Screening Tool to Identify Patients with Right Ventricular Dysfunction or Tricuspid Regurgitation after Negative Computerized Tomographic Pulmonary Angiography of the Chest

AbstractMany dyspneic patients who undergo computerized tomographic pulmonary angiography (CTPA) for presumed acute pulmonary embolism (PE) have no identified cause for their dyspnea yet have persistent symptoms, leading to more CTPA scanning. Right ventricular (RV) dysfunction or overload can signal treatable causes of dyspnea. We report the rate of isolated RV dysfunction or overload after negative CTPA and derive a clinical decision rule (CDR). We performed secondary analysis of a multicenter study of diagnostic accuracy for PE. Inclusion required persistent dyspnea and no PE. Echocardiography was ordered at clinician discretion. A characterization of isolated RV dysfunction or overload required normal left ventricular function and RV hypokinesis, or estimated RV systolic pressure of at least 40 mmHg. The CDR was derived from bivariate analysis of 97 candidate variables, followed by multivariate logistic regression. Of 647 patients, 431 had no PE and persistent dyspnea, and 184 (43%) of these 431 had e...
A novel electrode material for symmetrical SOFCs.

5 ] The application of this new SOFC conﬁ guration leads to a number of advantages. Possible sulfur poisoning or coke formation on the surface of the anode can be potentially eliminated by oper-ating the anode as a cathode; oxidant (typically air) will ﬂ ush any sulfur or carbon species absorbed on the electrode, thereby regenerating the electrode from sulfur or coke deactivation. In addition, a redox stable cathode is also expected to enhance the cathode durability since O
Multi-Modal Monitoring of Slip Along Frictional Discontinuities

Seismic wave transmission and digital image correlation (DIC) are employed to study slip processes along frictional discontinuities. A series of biaxial compression experiments are performed on gypsum specimens with non-homogeneous contact surfaces. The specimens are composed of two blocks with perfectly mated contact surfaces with a smooth surface with low frictional strength on the upper half and a rough surface with high frictional strength on the lower half. Compressional, P, and shear, S, wave pulses were transmitted through the discontinuity while digital images of the specimen surface were acquired during the test. A distinct peak in the amplitude of transmitted wave occurs prior to the peak shear strength and is considered a “precursor” to the failure. Precursors indicate that slip initiates from the smooth surface and extends to the rough surface as the shear load is increased. From the DIC data, slip is identified as a jump in the displacement field along the fracture that initiates from the smooth surface and propagates to the rough surface. Precursors are associated with an increase in the rate of slip across the discontinuity and are a measure of the reduction in the fracture shear stiffness.
Launch-Vehicle Simulations Using a Concurrent, Implicit Navier-Stokes Solver

A large-scale multibody launch-vehicle simulation at supersonic speed is described. The simulation was conducted on a 256-node Intel Delta machine using a concurrent implementation of the Aerospace Launch System Implicit/Explicit Navier-Stokes code. This general Navier-Stokes solver has been used for a broad range of practical simulations. Those of interest involve a variety of nozzle flows and multibody launch-vehicle configurations such as the Titan IV. The code utilizes a finite volume total-variation-diminishing scheme for computing both steady and unsteady solutions to the three-dimensional compressible Navier-Stokes equations. The scheme is second-order accurate in space and is fully vectorized for operation on Cray computers. A line-by-line relaxation algorithm is used to accelerate the convergence for steady-state solutions. The code employs a variety of features that increase its practical utility. These include multibody configurations, turbulence modeling, and propellant-burning capabilities. The procedures for extending this code to distributed-memory parallel computers are described. Results of the application to a Titan IV launch vehicle at freestream Mach number 1.6 are discussed. Nomenclature E,F,G = flux vectors E, F, G = transformed flux vectors e = total energy per unit volume cx>£.v> &z = unit vectors in the x,y, and z directions, respectively J = Jacobian of the transformation k = thermal conductivity p = pressure q = heat transfer vector T = temperature t = time
Neutrino Radiation Showing a Christodoulou Memory Effect in General Relativity

We describe neutrino radiation in general relativity by introducing the energy–momentum tensor of a null fluid into the Einstein equations. Investigating the geometry and analysis at null infinity, we prove that a component of the null fluid enlarges the Christodoulou memory effect of gravitational-waves. The description of neutrinos in general relativity as a null fluid can be regarded as a limiting case of a more general description using the massless limit of the Einstein–Vlasov system. Gigantic neutrino bursts occur in our universe in core-collapse supernovae and in the mergers of neutron star binaries.
What do non-relativistic CFTs tell us about Lifshitz spacetimes?

We study the reconstructability of (d + 2)-dimensional bulk spacetime from (d + 1)-dimensional boundary data, particularly concentrating on backgrounds which break (d + 1)-dimensional Lorentz invariance. For a large class of such spacetimes, there exist null geodesics which do not reach the boundary. Therefore classically one might guess some information is trapped in the bulk and thus invisible at the boundary. We show that this classical intuition correctly predicts the quantum situation: whenever there are null geodesics which do not reach the boundary, there are also “trapped scalar modes” whose boundary imprint is exponentially suppressed. We use these modes to show that no smearing function exists for pure Lifshitz spacetime, nor for any flow which includes a Lifshitz region. Indeed, for any (planar) spacetime which breaks (d + 1)-dimensional Lorentz invariance at any radius, we show that local boundary data cannot reconstruct complete local bulk data.
Black silicon solar thin-film microcells integrating top nanocone structures for broadband and omnidirectional light-trapping

Recently developed classes of monocrystalline silicon solar microcells (μ-cell) can be assembled into modules with characteristics (i.e., mechanically flexible forms, compact concentrator designs, and high-voltage outputs) that would be impossible to achieve using conventional, wafer-based approaches. In this paper, we describe a highly dense, uniform and non-periodic nanocone forest structure of black silicon (bSi) created on optically-thin (30 μm) μ-cells for broadband and omnidirectional light-trapping with a lithography-free and high-throughput plasma texturizing process. With optimized plasma etching conditions and a silicon nitride passivation layer, black silicon μ-cells, when embedded in a polymer waveguiding layer, display dramatic increases of as much as 65.7% in short circuit current, as compared to a bare silicon device. The conversion efficiency increases from 8.1% to 11.5% with a small drop in open circuit voltage and fill factor.
Granular-cell tumor of the duodenum: a case report

Abrikossof first described granular-cell tumor (GCT) in 1926. This tumor most typically occurs in the skin, the tongue, and the breast. The GI tract is a less common site of occurrence. In the GI tract, the esophagus is the most frequent site, with nearly 200 cases reported. Considerably fewer GCTs have been reported in the large intestine, the stomach, and the biliary tract. Only two reports have noted the appearance of GCT in the duodenum. In 1981, Johnston and Helwig described a series of 74 GCTs from the GI tract and the perianal region. They listed one GCT from the duodenum, without a detailed description of clinical findings. Recently, Onoda et al reported a duodenal GCT presenting with significant GI bleeding and requiring surgical excision. We report a third case of duodenal GCT and discuss its management.
Unimodality of partitions with distinct parts inside Ferrers shapes

We investigate the rank-generating function F λ of the poset of partitions contained inside a given shifted Ferrers shape λ . When λ has four parts, we show that F λ is unimodal when λ = { n , n - 1 , n - 2 , n - 3 } , for any n � 4 , and that unimodality fails for the doubly-indexed, infinite family of partitions of the form λ = { n , n - t , n - 2 t , n - 3 t } , for any given t � 2 and n large enough with respect to t .When λ has b � 3 parts, we show that our rank-generating functions F λ are all unimodal. However, the situation remains mostly obscure for b � 5 . In general, the type of results that we obtain present some remarkable similarities with those of the 1990 paper of D. Stanton, who considered the case of partitions inside ordinary (straight) Ferrers shapes.Along the way, we also determine some interesting q -analogs of the binomial coefficients, which in certain instances we conjecture to be unimodal. We state several other conjectures throughout this note, in the hopes to stimulate further work in this area. In particular, one of these will attempt to place into a much broader context the unimodality of the posets M ( n ) of staircase partitions, for which determining a combinatorial proof remains an outstanding open problem.
Vinylogous aldol products from chiral crotylsilanes obtained by enantioselective Rh(II) and Cu(I) carbenoid Si-H insertion.

Enantioenriched homoallylic ethers containing a α,β-unsaturated ester (syn-vinylogous aldol products) were directly accessed by Lewis acid catalyzed crotylation utilizing chiral silane 2. The reagents were prepared by enantioselective Si−H insertion to an α-diazovinylacetates using Davies’ Rh2(DOSP)4 catalyst or chiral Cu(I) Schiff base complex.
Emergence of localized plasticity and failure through shear banding during microcompression of a nanocrystalline alloy

Abstract Microcompression testing is used to probe the uniaxial stress–strain response of a nanocrystalline alloy, with an emphasis on exploring how grain size and grain boundary relaxation state impact the complete flow curve and failure behavior. The yield strength, strain hardening, strain-to-failure and failure mode of nanocrystalline Ni–W films with mean grain sizes of 5, 15 and 90 nm are studied using taper-free micropillars that are large enough to avoid extrinsic size effects. Strengthening is observed with grain refinement, but catastrophic failure through strain localization is found as well. Shear banding is found to cause failure, resembling the deformation of metallic glasses. Finally, we study the influence of grain boundary state by employing heat treatments that relax nonequilibrium boundary structure but leave grain size unchanged. A pronounced strengthening effect and increased strain localization are observed after relaxation in the finer grained samples.
Rationale, design, and baseline characteristics of a community-based comparative effectiveness trial to prevent type 2 diabetes in economically disadvantaged adults: The RAPID Study

Reaching Out and Preventing Increases in Diabetes (RAPID) is a community-based randomized trial evaluating the comparative costs and effectiveness of a group-based adaption of the DPP lifestyle intervention developed and implemented in partnership with the YMCA. RAPID enrolled adult primary care patients, with BMI 24 kg/m(2) or higher and abnormal glucose metabolism (HbA1c 5.7-6.9% or fasting plasma glucose 100-125 mg/dL). 509 participants were enrolled and randomized to one of two groups: standard clinical advice plus free-of-charge access to a group-based adaption of the DPP offered by the Y, versus standard clinical advice alone. Key outcomes for future analysis will include differences in body weight and other cardiovascular risk factors over a 24-month intervention period. At baseline, RAPID participants had a mean (SD) age of 51 ± 12.1 years, weight of 225.1 ± 56.2 lbs, and BMI of 36.9 ± 8.6 kg/m(2). 70.7% were women, 57.2% were African American, 35.4% were non-Hispanic White, and 3.2% were Hispanic. Mean HbA1c was 6.05 ± 0.34%. Additionally, 55.4% of participants had a baseline systolic blood pressure of ≥130 mmHg, 33.1% had a total blood cholesterol exceeding 200mg/dL, and 74% reported a household income of <$25,000. The RAPID Study successfully randomized a large cohort of participants with a wide distribution of age, body weight, and race who are at high risk for developing type 2 diabetes.
The Changing Face of Beauty

Beautiful faces, like clothing and body conformation, go in and out of fashion. Yet, certain women in every era are considered truly beautiful. Who, then, sets standards of facial beauty and how are women chosen as representative of an ideal? Identifying great beauties is easier than explaining why they are chosen, but answers to these elusive questions are suggested in art, literature, and a review of past events.