cssi/SciSciGPT-SciSciNet huggingface dataset:
Boundary Treatment and AN Efficient Pressure Algorithm for Internal Turbulent Flows Using the Pdf Method

SUMMARY The generalized Langevin model, which is used to model the motion of stochastic particles in the velocity‐ composition joint probability density function (PDF) method for reacting turbulent flows, has been extended to incorporate solid wall effects. Anisotropy of Reynolds stresses in the near-wall region has been addressed. Numerical experiments have been performed to demonstrate that the forces in the near-wall region of a turbulent flow cause the stochastic particles approaching a solid wall to reverse their direction of motion normal to the wall and thereby, leave the near-wall layer. This new boundary treatment has subsequently been implemented in a full-scale problem to prove its validity. The test problem considered here is that of an isothermal, non-reacting turbulent flow in a two-dimensional channel with plug inflow and a fixed back-pressure. An efficient pressure correction method, developed in the spirit of the PISO algorithm, has been implemented. The pressure correction strategy is easy to implement and is completely consistent with the time-marching scheme used for the solution of the Lagrangian momentum equations. The results show remarkable agreement with both k‐ and algebraic Reynolds stress model calculations for the primary velocity. The secondary flow velocity and the turbulent moments are in better agreement with the algebraic Reynolds stress model predictions than the k‐ predictions. The velocity‐composition joint PDF method 1 is an important tool for the computation of reacting turbulent flows. Starting with the conservation equations for mass, momentum and compositions of various species (for a chemically reactive flow), a single transport equation can be derived for the joint probability density function of velocity and composition, fu V x t , as described in Reference 1. The quantity fu dV d represents the probability that V U V dV and d occurs simultaneously, where U is the velocity vector, is the set of all scalars (temperature or enthalpy and concentrations) and V and are independent sample space variables corresponding to U and respectively. The transport equation for the joint PDF is a multidimensional partial differential equation and cannot be solved efficiently by traditional finite difference or finite volume techniques. The Monte Carlo method is used instead. In this method the fluid within the whole computational domain is discretized into representative ‘particles’ (or samples). These ‘particles’ then move with time and their motion is governed by their Lagrangian
Endochronic Theory of Cyclic Plasticity With Applications

Etude de la plastification d'un acier doux soumis a une charge cyclique. Modele mathematique et verification experimentale
Crystal growth and optical properties of lithium–lanthanide oxides: LiLnO2 (Ln = Nd, Sm, Eu, Gd and Dy)

Abstract Single crystals of Li Ln O 2 ( Ln = Nd, Sm, Eu, Gd, Dy) were grown out of a high temperature hydroxide melt. The crystal structures were determined by single crystal X-ray diffraction. These oxides crystallize in the space groups P 2 1 / c (Nd, Sm – δ-type) and Pnma (Eu, Gd, Dy – γ-type) as a function of the lanthanide cation size. The structure of the δ-type (Nd, Sm) contains lithium in approximately trigonal bipyramidal coordination environments that connect to form rings around two lanthanide atoms, where the rings interconnect to form zig-zag layers. The structure of the γ-type (Eu, Gd, Dy) contains lithium in a distorted tetrahedral coordination environment, where two edges are shared to generate infinite chains separated by the rare earth cation. LiGdO 2 and LiEuO 2 luminesce in the visible range with emission maxima at 610 and 609 nm respectively.
Correlation Functions of Strict Partitions and Twisted Fock Spaces

Using twisted Fock spaces, we formulate and study two twisted versions of the n-point correlation functions of Bloch–Okounkov, and then identify them with q-expectation values of certain functions on the set of (odd) strict partitions. We find closed formulas for the 1-point functions in both cases in terms of Jacobi θ-functions. These correlation functions afford several distinct interpretations.
Ultrasonic Removal of Near-Wellbore Damage Caused by Fines and Mud Solids

Laboratory experiments were conducted to investigate the feasibility of using ultrasonic energy to reduce formation damage caused by fines and mud solids. Cores were damaged with drilling muds in a dynamic filtration cell. Damage caused by fines migration was simulated with freshwater injection. The damaged cores were then treated with ultrasonic energy at various frequencies and intensities. The experiments were conducted with fully brine-saturated cores and cores partially saturated with decane. Permeability was monitored as a function of ultrasonic treatment time during backflow for three different sections of each core. Permeability increase, the depth of treatment, and the ultrasonic energy requirements were investigated for both sandstone and limestone cores. The results showed that permeability increased by a factor of three to seven after ultrasonic treatment for cores that were damaged by mud solids and fines migration. Treatment was successful for frequencies of approximately 20 to 80 kHz and acoustic intensities of approximately 20 to 250 W/m{sup 2}. For these wavefield parameters, the effective depth of treatment for reducing fines damage was approximately 2.5 in. Damage caused by mud infiltration penetrated only the first 2.5 in. of the cores, and thus, ultrasonic treatment had no effect on deeper sections.
The Political Economy of The Art of War

Sun Tzu's The Art of War deals with the economic aspects of military operations as well as some more general economic principles. This article studies several of its economic ideas in turn: on war and the state, the effect of war on economic affairs, and the role of incentives in promoting desired behavior within military organizations. It also discusses how the text treats ideal military strategy as a matter of opportunity discovery, analogous to entrepreneurship in the work of Israel Kirzner.
Synthesis and biological activity of 3-substituted 3-desoxynaltrindole derivatives.

Abstract The 3-unsubstituted and substituted analogs of naltrindole (NTI) were synthesized using palladium-catalyzed transformations, and their binding affinity to opioid receptors was determined. Although the 3-desoxy analog showed comparable δ selectivity with that of NTI, all of the novel compounds possessed low affinity for δ receptors indicating the important role of the 3-oxygen atom of NTI for interaction with δ-opioid receptors.
Protein Engineering by In Vivo Incorporation of Non-Natural Amino Acids: Control of Incorporation of Methionine Analogues by Methionyl-tRNA Synthetase

The incorporation of non-natural amino acids is an important strategy for engineering novel chemical and physical properties into natural and artificial proteins. The incorporation of amino acids into proteins in vivo is controlled in large part by the aminoacyl-tRNA synthetases (AARS). We have measured kinetic constants for in vitro activation of a set of methionine analogues by methionyl-tRNA synthetase (MetRS) via the ATP–PPi exchange reaction. Activation of methionine analogues in vitro correlates well with the ability of these analogues to support protein synthesis in vivo, substantiating the critical role of the AARS in controlling the incorporation of non-natural amino acids into proteins. Methionine analogues with k_(cat)/K_m values 2000-fold lower than those for methionine can support synthesis of a typical target protein (mDHFR) under standard conditions of protein expression. The kinetic constants correlate well with observed protein yields from a conventional bacterial expression host, indicating that the MetRS activity of the host can control the level of protein synthesis under certain conditions. Furthermore, increasing the MetRS activity of the bacterial host results in increased protein synthesis in media supplemented with the methionine analogues homoallylglycine and norleucine. These results suggest new strategies for incorporation of non-natural amino acids via manipulation of the AARS activity of a bacterial host.
Stereochemical control in the oxymercuration of 5-alken-1-ols

Abstract The axial preference which had been observed during the intramolecular reaction of cannabinoid precursors 2 and 3 is not a heteroatom-mediated directing effect. Rather, it reflects a kinetic preference which may be related to the anomeric effect.
Effective AdS/renormalized CFT

For an effective AdS theory, we present a simple prescription to compute the renormalization of its dual boundary field theory at \( \mathcal{O}\left( {{{1} \left/ {{{N^2}}} \right.}} \right) \). In particular, we define anomalous dimension holographically as the dependence of the wave-function renormalization factor on the radial cutoff in the Poincare patch of AdS. With this definition, the anomalous dimensions of both single- and double-trace operators are calculated. Three different dualities are considered with the field theory being CFT, CFT with a double-trace deformation and spontaneously broken CFT. For the second dual pair, we compute scaling corrections at the UV and IR fixed points of the RG flow triggered by the double-trace deformation. For the last case, we discuss whether our prescription is sensitive to the AdS interior or equivalently, the IR physics of the dual field theory.
Implicit Finite-Difference Simulations of Three-Dimensional Compressible Flow

An implicit finite-difference procedure for unsteady three-dimensional flow capable of handling arbitrary geometry through the use of general coordinate transformations is described. Viscous effects are optionally incorporated with a "thin-layer" approximation of the Navier-Stokes equations. An implicit approximate factorization technique is employed so that the small grid sizes required for spatial accuracy and viscous resolution do not impose stringent stability limitations. Results obtained from the program include transonic inviscid or viscous solutions about simple body configurations. Comparisons with existing theories and experiments are made. Numerical accuracy and the effect of three-dimensional coordinate singularities are also discussed.
Natural Convection From a Tube Bundle in a Thin Inclined Enclosure

Natural convection heat transfer coefficients for a rectangular array of eight tubes contained in a thin enclosure of aspect ratio 9.3:1 and inclined at 30 deg to the horizontal are measured for a range of transient operating modes typical of a load side heat exchanger in unpressurized integral collector-storage systems. Water is the working fluid, and thermal charging is accomplished via a constant heat flux on the upper boundary. All other boundaries are well insulated. Results for isothermal and stratified enclosures yield the following correlation for the overall Nusselt number: Nu D =(0.728±0.002)Ra 0.25 D, 4.0 ×10 5 ≤Ra D ≤1.4×10 7 . The flow field in the enclosure is inferred from measured temperature distributions. The temperature difference that drives natural convection is also determined. The results extend earlier work for the case of a single tube and provide limiting case heat transfer data for a tube bundle that occupies the upper portion of the collector storage.
An efficient procedure for the demethylation of aryl-methyl ethers in optically pure unusual amino acids

Abstract An efficient procedure was developed for the removal of methyl groups from aryl methyl ethers, without racemization, in derivatives of unusual amino acids that are of significant importance in the design of highly selective peptide protein ligands with specicific conformational topographical features. Demethylation of aromatic amino acids can result in an appreciable increase in receptor affinity, hence the new mild procedure which have been developed represents a facile practical method for demethylation of Tyr (OMe) derivatives, including novel sidechain ring or C-3 modified analogs.
Highly Enantioselective Hydrogenation of Cyclic Enol Acetates Catalyzed by a Rh–PennPhos Complex

The electron-rich and conformationally rigid (R,S,R,S)-Me-PennPhos ligand (shown schematically) appears to chelate rhodium and form well-defined chiral pockets. This allows, for example, efficient differentiation between the two enantiotopic approaches available to a substrate in a hydrogenation reaction. The Rh-Me-PennPhos complex is the first catalyst for the highly enantioselective asymmetric hydrogenation of cyclic enol acetates. For example, 3,4-dihydronaphth-1-yl acetate can be hydrogenated with up to 99% ee.
Organocatalytic Michael cycloisomerization of bis(enones): the intramolecular Rauhut-Currier reaction.

The utilization of enones as latent enolates enables regioselective enolate formation from chemically robust presursors. In this communication, we report a catalytic Michael cycloisomerization of bis(enones) under Morita−Baylis−Hillman conditions. Upon exposure to 10 mol % tributylphosphine, bis(enone) substrates afford both five- and six-membered ring products. Notably, unsymmetrical bis(enones) possessing sufficient steric or electronic bias yield single isomeric products.
Rab11 maintains connections between germline stem cells and niche cells in the Drosophila ovary.

All stem cells have the ability to balance their production of self-renewing and differentiating daughter cells. The germline stem cells (GSCs) of the Drosophila ovary maintain such balance through physical attachment to anterior niche cap cells and stereotypic cell division, whereby only one daughter remains attached to the niche. GSCs are attached to cap cells via adherens junctions, which also appear to orient GSC division through capture of the fusome, a germline-specific organizer of mitotic spindles. Here we show that the Rab11 GTPase is required in the ovary to maintain GSC-cap cell junctions and to anchor the fusome to the anterior cortex of the GSC. Thus, rab11 -null GSCs detach from niche cap cells, contain displaced fusomes and undergo abnormal cell division, leading to an early arrest of GSC differentiation. Such defects are likely to reflect a role for Rab11 in E-cadherin trafficking as E-cadherin accumulates in Rab11-positive recycling endosomes (REs) and E-cadherin and Armadillo (β-catenin) are both found in reduced amounts on the surface of rab11 -null GSCs. The Rab11-positive REs through which E-cadherin transits are tightly associated with the fusome. We propose that this association polarizes the trafficking by Rab11 of E-cadherin and other cargoes toward the anterior cortex of the GSC, thus simultaneously fortifying GSC-niche junctions, fusome localization and asymmetric cell division. These studies bring into focus the important role of membrane trafficking in stem cell biology.
Cupric siliconiobate. Synthesis and solid-state studies of a pseudosandwich-type heteropolyanion.

The Na+ and [Cu(en)2(H2O)2]2+ (en = ethylenediamine) salt of a pseudosandwich-type heteropolyniobate forms upon prolonged heating of Cu(NO3)2 and hydrated Na14[(SiOH)2Si2Nb16O54] in a mixed water−en solution. The structure [a = 14.992(2) A, b = 25.426(4) A, c = 30.046(4) A, orthorhombic, Pnn2, R1 = 6.04%, based on 25869 unique reflections] consists of two [Na(SiOH)2Si2Nb16O54]13− units linked by six sodium cations, and this sandwich is charge-balanced by five [Cu(en)2(H2O)2]2+ complexes, seven protons, and three additional sodium atoms (all per a sandwich-type cluster). Diffuse-reflectance UV−vis indicates that there is a λmax at 383 nm for the CuII d−d transition and the 29Si MAS NMR spectrum has two peaks at −78.2 ppm (151 Hz) and −75.5 ppm (257 Hz) for the two pairs of symmetry-equivalent internal [SiO4]4– and external [SiO3(OH)]3− tetrahedra, respectively. Unlike tungsten-based sandwich-type complexes, the [Na(SiOH)2Si2Nb16O54]13− units are linked exclusively by Na+ instead of one or more d-electron m...
Stereoselective Synthesis of cis- or trans-3,5-Disubstituted Pyrazolidines via Pd-Catalyzed Carboamination Reactions: Use of Allylic Strain to Control Product Stereochemistry Through N-Substituent Manipulation

The stereoselective synthesis of either trans- or cis-3,5-disubstituted pyrazolidines is accomplished via Pd-catalyzed carboamination reactions of unsaturated hydrazine derivatives. The products are obtained in good yield with up to >20:1 diastereoselectivity. Stereocontrol is achieved by modulating the degree of allylic strain in the transition state for syn-aminopalladation through a simple modification of the substrate N2-substituent. The pyrazolidine products can be further transformed to 3,5-disubstituted pyrazolines via deprotection/oxidation, or to substituted 1,3-diamines via N−N bond cleavage.
A note on sparse least-squares regression

We compute a sparse solution to the classical least-squares problem min"[email protected][email protected]?"2, where A is an arbitrary matrix. We describe a novel algorithm for this sparse least-squares problem. The algorithm operates as follows: first, it selects columns from A, and then solves a least-squares problem only with the selected columns. The column selection algorithm that we use is known to perform well for the well studied column subset selection problem. The contribution of this article is to show that it gives favorable results for sparse least-squares as well. Specifically, we prove that the solution vector obtained by our algorithm is close to the solution vector obtained via what is known as the ''SVD-truncated regularization approach''.
Preparation of Noble Metal Nanowires Using Hexagonal Mesoporous Silica SBA-15

We demonstrate a novel preparation method for the formation of metallic nanowires from gold, platinum, and silver using mesoporous silica SBA-15 as a template. SBA-15 controls the size and the growth direction of the nanowires and also prevents bulk aggregation of the metal. Nanowires can be isolated from the silica framework by treatment with HF.
Bubble geobarometry: A record of pressure changes, degassing, and regassing at Mono Craters, California

Water concentration profiles around bubbles offer a new kind of geobarometer. We measure H 2 O and CO 2 concentrations in glass adjacent to bubbles in pyroclastic obsidian from Mono Craters, California (United States). H 2 O and CO 2 concentration gradients are preserved during the eruption and record nonequilibrium degassing. A key result is that H 2 O is enriched in the glass surrounding the bubbles, indicating that bubbles were resorbing into the melt just prior to the eruption. The required pressure increase for the observed water enrichment is inferred to be the last in a series of pressure cycles with amplitude 5–30 MPa that are caused by repeated fragmentation and annealing. CO 2 concentrations vary substantially in individual obsidian clasts, suggesting that slow diffusion of CO 2 and nonequilibrium degassing contributes to high CO 2 /H 2 O ratios in pyroclastic obsidian from Mono Craters. These data are direct evidence for vapor-melt disequilibrium and demonstrate that degassing paths from a single parental melt need not be unidirectional. Hence volatile concentration gradients offer a tool for evaluating degassing models and inferring time scales of magmatic processes.
A Spitzer Study of Dusty Disks in the Scorpius-Centaurus OB Association

We have obtained Spitzer Space Telescope MIPS observations of 40 F- and G-type common proper motion members of the Scorpius-Centaurus OB association with ages between 5 and 20 Myr at 24 and 70 ?m. We report the detection of 14 objects that possess 24 ?m fluxes ?30% larger than their predicted photospheres, tentatively corresponding to a disk fraction of ?35%, including seven objects that also possess 70 ?m excesses ?100 times larger than their predicted photospheres. The 24 ?m plus 70 ?m excess sources possess high fractional infrared luminosities, LIR/L* = 7 ? 10-4 to 3 ? 10-3; either they possess optically thin, dusty ? Pictoris-like disks or compact, opaque HD 98800-like disks.
Adiabatic conversion of solar neutrinos.

The adiabatic conversion of solar electron neutrinos to muon neutrinos via the Mikheyev-Smirnov-Wolfenstein mechanism is discussed as a level-crossing problem. Solutions to the /sup 37/Cl puzzle obtained numerically by Mikheyev and Smirnov, Rosen and Gelb, and others are shown to form the boundary of the region in the deltam/sup 2/-sin/sup 2/2theta plane where adiabatic conversion occurs. Most of the region within this boundary is ruled out by the nonzero signal in Davis's experiment. The Landau-Zener description of the adiabatic boundary is employed.
Rippling of graphene

We show that ripples observed in free-standing graphene sheets can be explained as a consequence of adsorbed OH molecules sitting on random sites. The adsorbates cause the bonds between carbon atoms to lengthen slightly. Static buckles then result from a mechanism like the one that leads to buckling of leaves. Buckles caused by roughly 20% coverage of adsorbates are consistent with experimental observations.
Stoichiometric and catalytic deuterium and tritium labeling of "unactivated" organic substrates with cationic Ir(III) complexes.

Ir(III) complex [Cp*(PMe3)IrMe(CH2Cl2)][BArf] (1) was used to introduce deuterium stoichiometrically into substituted naphthalene/benzene templates and several “druglike” entities. The exchange process is tolerant of a wide array of functional groups. Labeling of warfarin using subatmospheric pressures of T2 led to specific activities and total activities rivaling current functional group directed tritium labeling methods. When paired with the appropriate deuterium donor, Cp*(PMe3)Ir(H3)OTf (4) was found to deuterate a number of organic compounds catalytically.
Chiral amine organocatalysts for the syn-aldol reaction involving substituted benzaldehydes and hydroxyacetone

Abstract A new series of cyclohexanediamine organocatalysts that contain the primary amine functionality has been designed, synthesized and tested as catalysts for the asymmetric aldol reaction involving hydroxyacetone and a variety of substituted benzaldehydes. High enantioselectivites and diasteroselectivites were obtained using catalyst 1a for these reactions. A key step in this reaction for the formation of the syn -product is the formation of a stable intramolecular hydrogen bonded Z -enamine isomer, which in addition to the steric bulk of the catalyst, serve to dictate the course of the stereochemical outcome of the reaction.
Extinction models for cancer stem cell therapy

Cells with stem cell-like properties are now viewed as initiating and sustaining many cancers. This suggests that cancer can be cured by driving these cancer stem cells to extinction. The problem with this strategy is that ordinary stem cells are apt to be killed in the process. This paper sets bounds on the killing differential (difference between death rates of cancer stem cells and normal stem cells) that must exist for the survival of an adequate number of normal stem cells. Our main tools are birth–death Markov chains in continuous time. In this framework, we investigate the extinction times of cancer stem cells and normal stem cells. Application of extreme value theory from mathematical statistics yields an accurate asymptotic distribution and corresponding moments for both extinction times. We compare these distributions for the two cell populations as a function of the killing rates. Perhaps a more telling comparison involves the number of normal stem cells NH at the extinction time of the cancer stem cells. Conditioning on the asymptotic time to extinction of the cancer stem cells allows us to calculate the asymptotic mean and variance of NH. The full distribution of NH can be retrieved by the finite Fourier transform and, in some parameter regimes, by an eigenfunction expansion. Finally, we discuss the impact of quiescence (the resting state) on stem cell dynamics. Quiescence can act as a sanctuary for cancer stem cells and imperils the proposed therapy. We approach the complication of quiescence via multitype branching process models and stochastic simulation. Improvements to the τ-leaping method of stochastic simulation make it a versatile tool in this context. We conclude that the proposed therapy must target quiescent cancer stem cells as well as actively dividing cancer stem cells. The current cancer models demonstrate the virtue of attacking the same quantitative questions from a variety of modeling, mathematical, and computational perspectives.
A unified strategy for the synthesis of (−)-maoecrystal Z, (−)-trichorabdal A, and (−)-longikaurin E

Herein we describe in full our investigations that led to the completion of the first total syntheses of (−)-maoecrystal Z, (−)-trichorabdal A, and (−)-longikaurin E. The unified strategy employs a Ti^(III)-mediated reductive epoxide coupling to rapidly prepare a key spirolactone. Highly diastereoselective Sm^(II)-mediated reductive cyclizations and a Pd^(II)-mediated oxidative cyclization enable the construction of three architecturally distinct ent-kauranoid frameworks from this common intermediate.
Lognormal Random-Field Models and Their Applications to Radar Image Synthesis

Lognormal random fields with multiplicative spatial interaction are proposed for modeling radar image intensity. Two particular classes of two-dimensional (2-D) lognormal random fields are introduced: multiplicative autoregressive (MAR), and multiplicative Mnrkov random fields (MMRF). The MAR and MMRF models are formulated as invertible point-transformations of Gaussian autoregressive and Gaussian Markov random fields (GMRF) and therefore possess many desirable properties. Least squares and maximum likelihood estimates for random-field parameters are presented, a decision rule is developed for selecting model order and transformations to normality as well, and techniques for synthesizing 2-D lognormal random fields are provided. Several Seasat synthetic aperture radar (SAR) images were tested using the decision rule developed in this paper and using the Kolmogorov-Smirnov (K-S) goodness-of-fit test. With both tests they were found to possess a good fit to lognormal statistics. MAR and MMRF models were fit to Seasat SAR images, and then the models were used to generate synthetic images that closely resemble the original SAR images both visually and in their variograms. This demonstrates the generality and appropriateness of the MAR and MMRF models for radar imagery.
Efficient Algorithms for the Hitchcock Transportation Problem

We consider the Hitchcock transportation problem on $n$ supply points and $k$ demand points when $n$ is much greater than $k$. The problem can be solved in $O(k n^2 \log n + n^2 \log^2 n)$ time if an efficient minimum-cost flow algorithm is directly applied. Applying a geometric method named splitter finding and a randomization technique, we can improve the time complexity when the ratio $c$ of the maximum supply to the minimum supply is sufficiently small. The expected running time of our randomized algorithm is $O(\frac{kn \log cn}{\log (n/k^4 \log^{2}k)})$ if $n > k^4 \log^{2} k$, and $O(k^5 \log^{2} n \log cn)$ if $n \le k^4 \log^{2} k$. If $n = \Omega(k^{4 + \epsilon})\ (\epsilon > 0)$ and $c = \mbox{poly}(n)$, the problem is solved in $O(kn)$ time, which is optimal.
Catalytic enantioselective O-nitrosocarbonyl aldol reaction of β-dicarbonyl compounds.

The first example of a Cu-catalyzed asymmetric O-nitrosocarbonyl aldol reaction is described. This novel protocol allows convenient access to highly enantioenriched α-hydroxy-β-ketoesters including the antibacterial natural product kjellmanianone (up to 99% ee). MnO2 was introduced as a mild efficient oxidant for the in situ generation of nitrosocarbonyl species from hydroxamic acid derivatives.
Deleterious Effects of Delayed Graft Function in Cadaveric Renal Transplant Recipients Independent of Acute Rejection

Background. In cadaveric renal transplantation, delayed graft function (DGF) correlates with poor long-term graft survival; however, whether its effects are independent of acute rejection is controversial. We wished to study the effect of DGF on graft survival, controlling for acute rejection, discharge creatinine, and human leukocyte antigen match. Methods. We analyzed 27,096 first cadaveric donor renal transplants reported to the UNOS Scientific Renal Transplant Registry between January 1994 and November 1997. DGF was defined as dialysis need in the first week. Acute rejection was recorded for initial hospitalization and within 6 months. Kaplan Meier survival curves were analyzed with the log rank test. Results. DGF increased the incidence of acute rejection before discharge (8% without DGF; 25% with DGF, P<0.01) and any acute rejections by 6 months (25% without DGF, 42% with DGF, P<0.01). Without early rejection, DGF reduced 1-year graft survival from 91 to 75% (P<0.0001) and graft half-life from 12.9 to 8.0 years. In kidneys with acute rejection within 6 months, DGF decreased 3-year graft survival from 77 to 60% and graft half-life from 9.4 to 6.2 years (P<0.001). With a discharge creatinine of less than 2.5 mg/dl, the difference in graft half-life between no DGF and no rejection (13.4 years) and DGF with rejection (9.8 years) was significant (P<0.001). Increased donor age and cold ischemia time additionally decreased graft survival, whereas a good human leukocyte antigen match could not overcome the deleterious effects of DGF or acute rejection. Conclusions. DGF is an important independent predictor of poor graft survival. Newer immunosuppressive strategies must minimize nonimmune and immune renal injury if long-term graft survival is to improve.
Peptide and protein synthesis by segment synthesis-condensation

The chemical synthesis of biologically active peptides and polypeptides can be achieved by using a convergent strategy of condensing protected peptide segments to form the desired molecule. An oxime support increases the ease with which intermediate protected peptides can be synthesized and makes this approach useful for the synthesis of peptides in which secondary structural elements have been redesigned. The extension of these methods to large peptides and proteins, for which folding of secondary structures into functional tertiary structures is critical, is discussed. Models of apolipoproteins, the homeo domain from the developmental protein encoded by the Antennapedia gene of Drosophila, a part of the Cro repressor, and the enzyme ribonuclease T1 and a structural analog have been synthesized with this method.
Smoothed Particle Hydrodynamics Calculations of Stellar Interactions

Smoothed particle hydrodynamics is a multidimensional Lagrangian method of numerical hydrodynamics that has been used to tackle a wide variety of problems in astrophysics. Here we develop the basic equations of the SPH scheme, and we discuss some of its numerical properties and limitations. As an illustration of typical astrophysical applications, we discuss recent calculations of stellar interactions, including collisions between main sequence stars and the coalescence of compact binaries.
Combining Galois with complex field coding for space–time communications

A joint scheme combining error-control coding (ECC) with complex-field coding (CFC) is proposed for space–time communications through flat or frequency-selective fading multiple-input multiple-output (MIMO) channels. It is shown that the diversity gain of this joint coding scheme is the product of the free distance of the ECC, the complex-field block encoder size, and the number of receiving antennas, which is computationally prohibitive to achieve using ECC alone. The decoding complexity with the proposed iterative decoder is comparable to a system without CFC. Numerical simulations for perfectly interleaved and HIPERLAN channels with both single and multiple antennas show great potential of the proposed joint coding scheme. Copyright © 2003 AEI
Holmium:YAG laser coronary angioplasty: results of a multicenter registry

To date, 1201 symptomatic patients with significant coronary artery disease were treated with the mid IR holmium:YAG (2.1 micron) laser in a multicenter study. Updated results of this study, as presented herein, substantiate the important role of this laser in treatment of lesions not ideal for conventional balloon angioplasty. This device is a safe and effective means of coronary revascularization.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Tau2000 conference summary

Abstract This is a review of some of the highlights of the 6th workshop on the physics of the τ lepton and its neutrino. This includes the test of lepton universality, measurement of Lorentz Structure, study of hadronic decays, direct evidence of tau neutrino, status of neutrino oscillations, and search for neutrinoless decays. This review concludes with a look at the prospect for τ physics in the future.
Understanding link-level 802.11 behavior: replacing convention with measurement

Since wireless signals propagate through the ether, they are significantly affected by attenuation, fading, and interference. As a result, it is often difficult to measure and understand fundamental wireless network behavior. This creates a challenge for both network researchers, who often rely on simulators to evaluate their work, and network managers, who need to deploy and optimize operational networks. Given the complexity of wireless networks, both communities often rely on simplifying rules, which often have not been validated using today's wireless radios. In this paper, we undertake a detailed analysis of 802.11 link-level behavior using real hardware and a physical layer wireless network emulator that gives us complete control over signal propagation. We replace conventional assumptions and possible misconceptions with actual recorded behavior. Additionally, we analyze the impact of our observations on commonly deployed networks. Our work contributes to a more accurate understanding of link-level behavior and enables the development of more accurate wireless network simulators.
Lifshitz transition in d-wave superconductors

The BCS-to-BEC evolution has been recently the focus of studies in superconductors and cold atomic gases. For a d-wave system, we show that a Lifshitz transition occurs at a critical particle density which separates two topologically distinct phases according to their quasiparticle excitation energies: a BCS-like gapless superconductor in the higher-density limit and a BEC-like fully gapped superconductor in the lower-density limit. This transition is second-order according to Ehrenfest's classification, but it occurs without a change in the symmetry of the order parameter and thus cannot be classified under Landau's scheme. To illustrate the nature of the transition, we compute the compressibility and the superfluid density as functions of particle density.
Synthesis of L-ribofuranosyl C-nucleosides.

Abstract C-Nucleosides, 4-amino-8-(β- l -ribofuranosyl)pyrazolo[1,5-a]-1,3,5-triazine ( 12 ) and 4-amino-7-(β- l -ribofuranosyl)-5H-pyrrolo[3,2-d]pyrimidine ( l -9-deazaadenosine, 22 ), were synthesized from the key intermediate, 3-dimethylamino-2-(2,3-O-isopropylidene-5-O-trityl- l -ribofuranosyl)acrylonitrile ( 8 ), which was prepared from l -xylose in 11 steps.
Possible energy gain for a plasma-liner-driven magneto-inertial fusion concept

A one-dimensional parameter study of a Magneto-Inertial Fusion (MIF) concept indicates that significant gain may be achievable. This concept uses a dynamically formed plasma shell with inwardly directed momentum to drive a magnetized fuel to ignition, which in turn partially burns an intermediate layer of unmagnetized fuel. The concept is referred to as Plasma Jet MIF or PJMIF. The results of an adaptive mesh refinement Eulerian code (Crestone) are compared to those of a Lagrangian code (LASNEX). These are the first published results using the Crestone and LASNEX codes on the PJMIF concept.
Introducing Song Form Intelligence into Streaming Audio

When receiving streaming media over a low bandwidth wireless connection, users can experience not only packet losses but also extended service interruptions. These dropouts can last for as long as 15 sec. During this time no packets are received and if not addressed, these dropped packets cause unacceptable interruptions in the audio stream. A long dropout of this kind may be overcome by ensuring that the buffer at the client is large enough. However, when using fixed bit rate technologies such as Windows Media or Real Audio, this may only be done by buffering packets for an extended period (10 sec or more) before starting to play the track. During this period, many users are likely to lose interest or become frustrated. This research presents a novel semantic audio error concealment buffering technology, made possible by the song form structure. It enables the audio to start playing within two or three sec, while at the same time using a small proportion of the available bandwidth to fill the client device buffer with received packets but categorised into structures of the song. A pattern matching run-time algorithm works to identify portions of the audio stream and when a dropout does occur relevant section of the buffered audio are inserted so as to create a perfect match for the lost audio. Our algorithm can be shown to increase reliability on bursty wireless networks.
Child care choices, food intake, and children's obesity status in the United States.

Abstract This article studies two pathways in which selection into different types of child care settings may affect likelihood of childhood obesity. Frequency of intake of high energy-dense and low energy-dense food items may vary across care settings, affecting weight outcomes. We find that increased use of paid and regulated care settings, such as center care and Head Start, is associated with higher consumption of fruits and vegetables. Among children from single-mother households, the probability of obesity increases by 15 percentage point with an increase in intake of soft drinks from four to six times a week to daily consumption and by 25 percentage point with an increase in intake of fast food from one to three times a week to four to six times a week. Among children from two-parent households, eating vegetables one additional time a day is associated with 10 percentage point decreased probability of obesity, while one additional drink of juice a day is associated with 10 percentage point increased probability of obesity. Second, variation across care types could be manifested through differences in the structure of the physical environment not captured by differences in food intake alone. This type of effect is found to be marginal and is statistically significant among children from two-parent households only. Data are used from the Early Childhood Longitudinal Study – Birth Cohort surveys ( N = 10,700; years = 2001–2008). Children's age ranged from four to six years in the sample.
Gravitational wave searches with ground tracking networks

Long-term experiments designed to search for gravitational waves (GW) have been performed with the Pioneer 10 and 11 spacecraft, and are planned for NASA's Galileo and ESA's Ulysses spacecraft. The result of a passing monochromatic GW is a sinusoidal modulation of the Doppler series that depends on the round-trip light time (RTLT) to a spacecraft and on the angle between the radiation propagation direction and the spacecraft link. Thus, an ideal experiment must have coverage and monitoring of interplanetary spacecraft during cruise that must be continuous as the earth turns to permit observation of complete three-pulse responses over the RTLT. To achieve this goal, an international 40-day Joint Tracking Experiment (JTE) is planned for the fall of 1987 for continuous tracking of the two spacecraft, when both will be near solar opposition. A diagram of the tracking geometry during the JTE and diagrams illustrating theoretical GW properties are included.
A hybrid computational method for partial differential equations

A hybrid computational method for partial differential equations which significantly reduces the time of solutions and error propagation is presented. It is a truly hybrid method, relying on the accurate algebraic capability of the digital machine and the integration capability and speed of the analog.
Incorporating Size Selectivity into Synergistic Solvent Extraction: A Review of Crown Ether-Containing Systems

This paper provides a comprehensive review of synergistic solvent extraction using crown ethers with a focus on the role of both extractants in facilitating cation-specific separations. An introduction to the various equilibria affecting synergistic extraction using crown ethers is followed by a review of the work published in this field during the 1972-1999 time period. The influence of various solvent extraction parameters on the potential for cation-selective synergism is critically examined. Those synergistic extractant combinations showing cation selectivity are highlighted, as are the fundamental investigations that are the foundation of the current understanding of synergistic solvent extraction using crown ethers.
Divergence of dipole sums and the nature of non-Lorentzian exponentially narrow resonances in one-dimensional periodic arrays of nanospheres

The origin and properties of non-Lorentzian spectral lines in linear chains of nanospheres are discussed. The lines are shown to be super-exponentially narrow with the characteristic width exp[−C(h/a)3] where C is a numerical constant, h the spacing between the nanospheres in the chain and a the sphere radius. The fine structure of these spectral lines is also investigated.
Low-order observer for discrete-time systems with slow and fast modes

Linear shift-invariant discrete-time systems with slow and fast modes are considered. In particular, investigation of these systems with inadequately modelled but stable fast dynamics, is made. Conditions under which a low-order observer can be designed for estimating the slow states from knowledge of only the degenerate model, are given. A design methodology, which is robust with respect to the neglected fast dynamics, is presented for stabilizing systems satisfying these conditions.
Aza-Tryptamine Substrates in Monoterpene Indole Alkaloid Biosynthesis

Biosynthetic pathways can be hijacked to yield novel compounds by introduction of novel starting materials. Here we have altered tryptamine, which serves as the starting substrate for a variety of alkaloid biosynthetic pathways, by replacing the indole with one of four aza-indole isomers. We show that two aza-tryptamine substrates can be successfully incorporated into the products of the monoterpene indole alkaloid pathway in Catharanthus roseus. Use of unnatural heterocycles in precursor-directed biosynthesis, in both microbial and plant natural product pathways, has not been widely demonstrated, and successful incorporation of starting substrate analogs containing the aza-indole functionality has not been previously reported. This work serves as a starting point to explore fermentation of aza-alkaloids from other tryptophan- and tryptamine-derived natural product pathways.
Optimal three-dimensional flight control of a supersonic fighter

This paper discusses optimal three-dimensional flight control of a supersonic fighter through an onboard automatic guidance and control system. This system is simulated to check the speed requirements of the algorithms to be solved before being implemented in real hardware. A very-high-speed digital computer is used for this time-critical simulation. In the simulation optimal trajectories are generated in real time, on line. Results obtained from the particular problem of a real-time, online minimum-time supersonic chandelle with prescribed final point are displayed.
An adaptive checkpointing scheme for distributed databases with mixed types of transactions

A checkpointing algorithm that is noninterfering with transaction processing is presented. It prevents the well-known domino effect and saves the intermediate results of a long-lived transaction in an adaptive manner, managing effectively both short- and long-lived transactions in the system. >
Social, lifestyle and demographic inequalities in hypertension care.

Aims: Recent nationwide in-depth analyses on inequalities in hypertension prevalence and care are scarce. This study assessed sociodemographic and lifestyle factors associated with the prevalence, awareness, treatment and control of hypertension in Finland. Methods: A representative nationwide sample (participation rate 58%) of the Finnish adult population underwent a health examination and interview in 2011. After excluding participants with missing data, 4230 people were included in the analyses. Weighted regression modelling was used to explore the associations of sociodemographic and lifestyle factors with the prevalence, awareness, treatment and control of hypertension. Results: The prevalence, awareness, treatment and control rates of hypertension (blood pressure ⩾140/90 mmHg or antihypertensive medication) in Finland were 47%, 57%, 51% and 48%, respectively. Older age, male sex, lower education, retirement, higher BMI, never-smoking and heavy alcohol use were associated with a higher prevalence of ...
Bayes factors based on test statistics

Summary. Traditionally, the use of Bayes factors has required the specification of proper prior distributions on model parameters that are implicit to both null and alternative hypotheses. I describe an approach to defining Bayes factors based on modelling test statistics. Because the distributions of test statistics do not depend on unknown model parameters, this approach eliminates much of the subjectivity that is normally associated with the definition of Bayes factors. For standard test statistics, including the χ2-, F-, t- and z-statistics, the values of Bayes factors that result from this approach have simple, closed form expressions.
An invariant of finite group actions on shifts of finite type

We describe a pair of invariants for actions of finite groups on shifts of finite type, the left-reduced and right-reduced shifts. The left-reduced shift was first constructed by Fiebig, who showed that its zeta function is an invariant, and in fact equal to the zeta function of the quotient dynamical system. We also give conditions for expansivity of the quotient, and applications to combinatorial group theory, knot theory and topological quantum field theory.
The anisotropic and rheological structure of the oceanic upper mantle from a simple model of plate shear

SUMMARY We have developed a channel flow model that dynamically couples plate motion and mantle stress with a composite rheology (diffusion creep and dislocation creep) to study the rheological and anisotropic structures of the oceanic upper mantle. A semi-analytic approach is used to solve for mantle stress and viscosity, allowing fast calculations and exploration of a wide range of rheological parameters. Mantle stress in our model is due to shearing by a moving plate. By comparing mantle stress with a transition stress for dislocation creep, we identify regions where either diffusion creep or dislocation creep is active. Deformation by dislocation creep results in a mineral fabric that may be responsible for observed seismic anisotropy. Our study suggests that there is an important relation between plate motion, seismic anisotropy, mantle viscosity and transition stress. Using laboratory results for rheological parameters, we find that dislocation creep exists only in a layer at certain depths in the upper mantle. For a plate velocity of 10 cm yr −1 , an asthenospheric viscosity of 10 19 Pa s and an asthenospheric transition stress of 0.1 MPa, our model predicts a ∼200 km thick dislocation creep layer, which is broadly consistent with the observations of seismic anisotropy. For a plate velocity of 10 cm yr −1 and an asthenospheric transition stress of 0.1 MPa, the asthenospheric viscosity needs to be greater than 5 × 10 18 Pa s to produce any dislocation creep deformation, and the