cssi/SciSciGPT-SciSciNet huggingface dataset:
Hard X-ray and hot electron environment in vacuum hohlraums at NIF

Time resolved hard x-ray images (hv > 9 keV) and time integrated hard x-ray spectra (hv = 18-150 keV from vacuum hohlraums irradiated with four 351 nm wavelength NIF laser beams are presented as a function of hohlraum size and laser power and duration. The hard x-ray images and spectra provide insight into the time evolution of the hohlraum plasma filling and the production of hot electrons. The fraction of laser energy detected as hot electrons (f hot ) shows correlation with both laser intensity and with an analytic plasma filling model.
Synthesis of 5′-Fluoro-5′-deoxy-and 5′-Amino-5′-Deoxytoyocamycin and Sangivamycin and Some Related Derivatives

Abstract A series of 5′-substituted analogs of toyocamycin were prepared by condensation of silylated 4-amino-6-bromo-5-cyanopyrrolo[2,3-d]pyrimidine with protected 5-azido-5-deoxy- or 5-fluoro-5-deoxyribofuranose followed by debromination and deblocking. Alternatively, 5′-azido-5′-deoxytoyocamycin was prepared by azidation of toyocamycin. Conversion of the 5-nitrile function of the toyocamycin derivatives into a carboxamide or a thiocarboxamide gave the corresponding analogs of sangivamycin or thiosangivamycin while reduction of the 5′-azido-5′-deoxy nucleosides provided 5′-amino-5′-deoxy derivatives.
Asymmetric Total Synthesis of (+)-Codeine via Intramolecular Carbenoid Insertion

A strategy was devised for the synthesis of codeine that employed intramolecular insertion of a carbenoid into a benzylic methine CH bond for creation of the C13 quaternary center and construction of the pentacyclic skeleton of the alkaloid. The synthesis began from isovanillin, and asymmetry was introduced through catalytic hydrogenation of its Stobbe condensation product 7 over a chiral catalyst (8). The product (S)-9 was advanced to tetralone 12, which underwent Robinson annulation to give the phenanthrenone 33. The latter was brominated and treated with base to afford the fused benzofuran 35. Reduction with hydride followed by catalytic hydrogenation produced the tetracycle 44, which was converted to diazoketone 48. The latter was reacted in the presence of catalytic Rh2(OAc)4 to furnish the pentacyclic product 49. Beckmann rearrangement of the derived oxime brosylate 59 gave lactam 57, and the synthesis of (+)-1 (the nonnatural enantiomer of codeine) was completed after oxidation to 63, introduction ...
Diophantine and cohomological dimensions

We give explicit linear bounds on the p-cohomological dimension of a field in terms of its Diophantine dimension. In particular, we show that for a field of Diophantine dimension at most 4, the 3-cohomological dimension is less than or equal to the Diophantine dimension.
Heavy quarks and heavy quarkonia as tests of thermalization

We present here a brief summary of the presentation given at the Quark-Gluon-Plasma Thermalization Workshop in Vienna, Austria in August 2005, directly following the International Quark Matter Conference in Hungary.
New Resultant Inequalities and Complex Polynomial Factorization

The author deduces some new probabilistic estimates on the distances between the zeros of a polynomial $p(x)$ by using some properties of the discriminant of $p(x)$ and applies these estimates to improve the fastest deterministic algorithm for approximating polynomial factorization over the complex field. Namely, given a natural $n$, positive $\epsilon$, such that $\log (1/\epsilon) = O(n\log n)$, and the complex coefficients of a polynomial $p(x)=\sum^n_{i=0} p_ix^i$, such that $p_n\ne 0$, $\sum _i |p_i| \le 1$, a factorization of $p(x)$ (within the error norm $\epsilon$) is computed as a product of factors of degrees at most $n/2$, by using $O(\log^2n)$ time and $n^3$ processors under the PRAM arithmetic model of parallel computing or by using $O(n^2\log^2 n)$ arithmetic operations. The algorithm is randomized, of Las Vegas type, allowing a failure with a probability at most $\delta$, for any positive $\delta < 1$ such that $\log (1/\delta) = O(\log n)$. Except for a narrow class of polynomials $p(x)$, these results can be also obtained for $\epsilon$ such that $\log(1/\epsilon) =O(n^2\log n)$.
Potent inhibition of retinoic acid metabolism enzyme(s) by novel azolyl retinoids.

Novel (±)-4-azolyl retinoic acid analogues 4, 5, 7 and 8 have been designed and synthesized and have been shown to be powerful inhibitors of hamster microsomal all-trans-retinoic acid 4-hydroxylase enzyme(s). (±)-4-(1H-Imidazol-1-yl)retinoic acid (4) is the most potent inhibitor of this enzyme reported to date.
Knowledge Spillovers, Mergers and Public Policy in Economic Clusters

This paper investigates how market concentration affects research activity in an economic cluster. The firms in the cluster play a two-stage game. In the first stage the firms choose whether or not to engage in costly research that generates technological improvements that spill over to the other firms in the cluster. The more firms engaged in research the richer or more profitable is the pool of knowledge that spills over. In the second stage after the knowledge spillovers have occurred, firms compete in quantities. We solve for the symmetric mixed strategy equilibrium to the first stage of the game, and find that too low a degree of concentration in the cluster will destroy firms' incentives to undertake research and so the cluster risks stagnation. We explore whether a merger can stimulate research activity by increasing concentration in the cluster. Finally, we consider a public policy response to stagnation and analyze whether a direct public subsidy to stimulate research is preferable to a self-financing arrangement.
Conformal models of Thirring type and the affine Virasoro construction

Abstract We investigate a class of models in 1+1 dimensions with four fermion interaction term. At each order of the perturbation expansion, the models are ultraviolet finite and Lorentz non-invariant. We show that for certain privileged values of the coupling constants, Lorentz symmetry is restored, and indeed the model turns out to be conformally invariant. This phenomenon is both quantum mechanical and non-perturbative.
The Geological Society of America Bulletin and the development of quantitative geomorphology

The influence of the Geological Society of America Bulletin on the development of quantitative geomorphology is demonstrated by three papers: Horton (1945), Mackin (1948), and Strahler (1952a), all published in the Bulletin . Horton (1945) advocated a move from qualitative to quantitative approaches in the study of landforms. He proposed quantitative tools and techniques by which we could analyze the landscapes around us. His paper not only stimulated statistical and mathematical approaches to geomorphic research and description but raised fundamental questions such as the randomness or determinism of surface processes. Mackin9s (1948) paper was influential in the development of quantitative geomorphology because it prompted the work of Leopold and many others on the hydraulic geometry of river channels. In that paper, he also proposed several concepts fundamental to the dynamic geomorphology system of Strahler. Strahler9s (1952a) paper set forth some guiding principles underlying quantitative methods of investigating landforms. He advocated the use of statistical techniques in landscape analyses of all geomorphic processes. In that paper, Strahler also integrated Mackin9s (1948) concept of system and that of a dynamic equilibrium into a new "dynamic" geomorphology. These three papers were fundamental in the origin and growth of quantitative, process-oriented geomorphology. Future trends lie in the fields of environmental geomorphology, global and planetary studies, and morpho-tectonics with accent on applied problems and cooperation with other disciplines.
Continuous ethanol fermentation using immobilized yeast in a fluidized bed reactor

Continuous ethanol fermentation of glucose using fluidized bed technology was studied. Saccharomyces cerevisiae were immobilized and retained on porous microcarriers. Over two-thirds of the total reactor yeast cell mass was immobilized. Ethanol productivity was examined as dilution rate was varied, keeping all other experimental parameters constant. Ethanol yield remained high at an average of 0.36 g ethanol g−1 glucose (71% of theoretical yield) as the dilution rate was increased stepwise from 0.04 h−1 to 0.14 h−1. At a dilution rate of 0.15 h−1, the ethanol yield steeply declined to 0.22 g ethanol g−1 glucose (44% of theoretical yield). The low maximum percentage of theoretical yield is primarily due to an extended mean cell residence time, and possibly due to the inhibitory effect of a high dissolved carbon dioxide concentration, enhanced by the probable intermittent levels of low pH in the reactor. Constant ethanol production was possible at a high glucose loading rate of 840 g dm−3 day−1 (attained at a dilution rate of 0.14 h−1). Although the highest average ethanol concentration (97.14 g dm−3) occurred at the initial dilution rate of 0.04 h−1, the peak average ethanol production rate (2.87 g (g yeast)−1 day−1) was reached at a greater dilution rate of 0.11 h-1. Thus, the optimal dilution rate was determined to be between 0.11 h−1 and 0.14 h−1. Ethanol inhibition on yeast cells was absent in the reactor at average bulk-liquid ethanol concentrations as high as 97.14 g dm−3. In addition, zero-order kinetics on ethanol production and glucose utilization was evident.
Advancements in Vibration Monitoring for the Mining Industry

Rotating machinery assets are a fundamental necessity in the mining industry. Furthermore, the proper maintenance and ability to monitoring these key assets is important to maximizing the operations. This paper will discuss the merits and advancements in vibration monitor systems and the direct impact on supervisory control and data acquisition and predictive maintenance models.
Mechanical Properties of Sintered and Nitrided Laser‐Synthesized Silicon Powder

Pure and boron-doped silicon powders made by laser-heated gas-phase synthesis were densified by pressureless sintering and then nitrided. Modulus of rupture, hardness, and fracture toughness were measured for reaction-bonded Si3N4 samples made from these powders and for other standard materials for comparison.
Standardized coordinate systems for solar image data

Abstract The current state of describing the coordinates of solar image data is chaotic, and does not take into account the most recent developments in the coordinate systems for astronomy in general, especially as related to FITS files. A set of formal systems for describing the coordinates of solar image data is proposed. These systems build on current practice in applying coordinates to solar image data. Both heliographic and heliocentric coordinates are discussed. A distinction is also drawn between heliocentric and helioprojective coordinates, where the latter takes the observer's exact geometry into account. The extension of these coordinate systems to observations made from non-terrestial viewpoints, such as STEREO and Solar Probe, is discussed. A formal system for incorporation of these coordinates into FITS files, based on the FITS World Coordinate System, is described.
BIHOMOGENEITY AND MENGER MANIFOLDS

Abstract It is shown that for every triple of integers (α,β,γ) such that α ⩾ 1, β ⩾ 1, and γ ⩾ 2, there is a homogeneous, non-bihomogeneous continuum whose every point has a neighborhood homeomorphic to the Cartesian product of Menger compacta μ α × μ β × μ γ . In particular, there is a homogeneous, non-bihomogeneous Peano continuum of covering dimension four.
Brillouin scattering in diamond

The Brillouin spectrum of diamond excited with either the ${\mathrm{Ar}}^{+}$ or He-Ne laser radiation is measured with a triple-passed piezoelectrically scanned Fabry-Perot interferometer. The polarization features and the selection rules have been verified for a number of scattering geometries. From the measured frequency shifts of the Brillouin components, the following values are obtained for the elastic moduli: ${c}_{11}=10.764\ifmmode\pm\else\textpm\fi{}0.002$, ${c}_{12}=1.252\ifmmode\pm\else\textpm\fi{}0.023$, and ${c}_{44}=5.774\ifmmode\pm\else\textpm\fi{}0.014$ in units of ${10}^{12}$ dyn/${\mathrm{cm}}^{2}$. The relative intensities of the observed Brillouin components for a variety of scattering geometries are consistent with the following elasto-optic contants: ${p}_{44}=\ensuremath{-}0.172$ and ${p}_{11}\ensuremath{-}{p}_{12}=\ensuremath{-}0.292$ determined by Denning et al. and ${p}_{11}+2{p}_{12}=\ensuremath{-}0.1640$ obtained by Schneider. From a comparison of the Brillouin spectrum and the Raman spectrum associated with the zone-center optical phonon, observed under identical conditions, we obtain a value for the single independent component characterizing the Raman tensor per unit cell, viz., $|a|=4.4\ifmmode\pm\else\textpm\fi{}0.3$ ${\mathrm{\AA{}}}^{2}$.
THE OUTER LIMITS OF THE M31 SYSTEM: KINEMATICS OF THE DWARF GALAXY SATELLITES AND XXVIII and AND XXIX

We present Keck/DEIMOS spectroscopy of resolved stars in the M31 satellites And XXVIII and And XXIX. We show that these are likely self-bound galaxies based on 18 and 24 members in And XXVIII and And XXIX, respectively. And XXVIII has a systemic velocity of -331.1 {+-} 1.8 km s{sup -1} and a velocity dispersion of 4.9 {+-} 1.6 km s{sup -1}, implying a mass-to-light ratio (within r{sub 1/2}) of {approx}44 {+-} 41. And XXIX has a systemic velocity of -194.4 {+-} 1.5 km s{sup -1} and velocity dispersion of 5.7 {+-} 1.2 km s{sup -1}, implying a mass-to-light ratio (within r{sub 1/2}) of {approx}124 {+-} 72. The internal kinematics and implied masses of And XXVIII and And XXIX are similar to those of dwarf spheroidals (dSphs) of comparable luminosities, implying that these objects are dark-matter-dominated dwarf galaxies. Despite the large projected distances from their host (380 and 188 kpc), the kinematics of these dSph suggest that they are bound M31 satellites.
On-chip cache device scaling limits and effective fault repair techniques in future nanoscale technology

Abstract In this study, we investigate different cache fault-tolerance techniques to determine which will be most effective when on-chip memory cell defect probabilities exceed those of current technologies, which is highly anticipated in processor on-chip caches manufactured with future nanometer scale technologies. Our most significant finding from this study is that the devices in on-chip memory cells cannot be scaled at the same rate as devices in logic circuits due to the increasing number of erroneous memory cells with voltage scaling, requiring strong fault-tolerance techniques. Second, we propose a technique to minimize performance impacts under aggressive technology and voltage scaling. It works by merging pairs of faulty cache lines into good lines and performs better than TMR at high error rates. We also estimate up to 28% energy savings at low voltage, relative to a recent fault-tolerance scheme [A. Agarwal et al. A process-tolerant cache architecture for improved yield in nanoscale technologies. IEEE Trans. VLSI Syst. 13(1) (2005) 27–38].
Selective cleavage of allyl ethers

Abstract A simple, one-step method for the selective cleavage of allyl ethers to alcohols has been developed by use of Ti(O-i-Pr)4 and a commercially available Grignard reagent.
DETECTION OF GASEOUS EFFLUENTS FROM AIRBORNE LWIR HYPERSPECTRAL IMAGERY USING PHYSICS-BASED SIGNATURES

Detection of gaseous effluent plumes from airborne platforms provides a unique challenge to the remote sensing community. The measured signatures are a complicated combination of phenomenology including effects of the atmosphere, spectral characteristics of the background material under the plume, temperature contrast between the gas and the surface, and the concentration of the gas. All of these quantities vary spatially further complicating the detection problem. In complex scenes simple estimation of a “residual” spectrum may not be possible due to the variability in the scene background. A common detection scheme uses a matched filter formalism to compare laboratory-measured gas absorption spectra with measured pixel radiances. This methodology can not account for the variable signature strengths due to concentration path length and temperature contrast, nor does it take into account measured signatures that are observed in both absorption and emission in the same scene. We have developed a physics-based, forward model to predict in-scene signatures covering a wide range in gas / surface properties. This target space is reduced to a set of basis vectors using a geometrical model of the space. Corresponding background basis vectors are derived to describe the non-plume pixels in the image. A Generalized Likelihood Ratio Test is then used to discriminate between plume and non-plume pixels. Several species can be tested for iteratively. The algorithm is applied to airborne LWIR hyperspectral imagery collected by the Airborne Hyperspectral Imager (AHI) over a chemical facility with some ground truth. When compared to results from a clutter matched filter the physics-based signature approach shows significantly improved performance for the data set considered here.
Solvent controlled mechanistic dichotomy in a Au(III)-catalyzed, heterocyclization triggered, Nazarov reaction

Tandem Au(III)-catalyzed heterocyclization/Nazarov cyclizations leading to substituted carbocycle fused furans are described. An interesting dichotomy of reaction pathways as a function of solvent, confirmed by the isolation and trapping of reaction intermediates, provided a basis for computational studies that supported the experimental findings.
An Outline of the Requirements for a Computer-Aided Design System

In the early 1950's at M.I.T. the Servomechanisms Laboratory (now the Electronic Systems Laboratory) devised and developed the first automatically controlled milling machine. The controlling information for the machine was introduced in the form of punched paper tape, on which all dimensional information and instructions for the various feeds and cutter speeds was contained. At first the punched paper tape was prepared manually by some human operator who translated, in effect, the detail drawing of the part to be machined into numerical form and then into appropriate patterns of holes in the tape. This was a tedious and entirely mechanical chore, and it was only natural that short cuts in the process began to suggest themselves. The scope of such short cuts began to spread through the fabric of the technique, and it was not long before the computer was involved in implementing them.
Gibbs phenomenon in structural mechanics

The concepts of complementary boundary condition and interior condition are discussed. Guidelines are developed to eliminate the Gibbs effect when selecting trial functions for the series expansion
A NOVEL NEUTROSOPHIC LOGIC SVM (N-SVM) AND ITS APPLICATION TO IMAGE CATEGORIZATION

Neutrosophic logic is a relatively new logic that is a generalization of fuzzy logic. In this paper, for the first time, neutrosophic logic is applied to the field of classifiers where a support vector machine (SVM) is adopted as the example to validate its feasibility and effectiveness. The proposed neutrosophic set is integrated into a reformulated SVM, and the performance of the obtained classifier N-SVM is evaluated under a region-based image categorization system. Images are first segmented by a hierarchical two-stage self-organizing map (HSOM) using color and texture features. A novel approach is proposed to select the training samples of HSOM based on homogeneity properties. A diverse density support vector machine (DD-SVM) framework is then applied to viewing an image as a bag of instances corresponding to the regions obtained from image segmentation. Each bag is mapped to a point in the new bag space, and the categorization is transformed to a classification problem. Then, the proposed N-SVM is used as the classifier in the new bag space. N-SVM treats samples differently according to the weighting function, and it helps to reduce the effects of outliers. Experimental results have demonstrated the validity and effectiveness of the proposed method which may find wide applications in the related areas.
MetaMesh: A hierarchical computational model for design and fabrication of biomimetic armored surfaces

Many exoskeletons exhibit multifunctional performance by combining protection from rigid ceramic components with flexibility through articulated interfaces. Structure-to-function relationships of these natural bioarmors have been studied extensively, and initial development of structural (load-bearing) bioinspired armor materials, most often nacre-mimetic laminated composites, has been conducted. However, the translation of segmented and articulated armor to bioinspired surfaces and applications requiresnewcomputationalconstructs.Weproposeanovelhierarchicalcomputationalmodel,MetaMesh, that adapts a segmented fish scale armor system to fit complex ‘‘host surfaces’’. We define a ‘‘host’’ surface as the overall geometrical form on top of which the scale units are computed. MetaMesh operates in three levels of resolution: (i) locally—to construct unit geometries based on shape parameters of scales as identified and characterized in the Polypterus senegalus exoskeleton, (ii) regionally—to encode
The reasonability of panpsychism

Panpsychism is the theory that each thing in the universe is conscious. In other words, panpsychism says that it is like something to be anything, from humans down to electrons. At face value, panpsychism can seem strange, weird, and even farfetched. In the past, many scientists and philosophers have rejected panpsychism because of its unpalatable conclusions; how could particles down at the microphysical level have conscious experiences? However, we ought not reject panpsychism under the guise of Occam's razor. Each available theory of conscious is riddled with its own problems. Thus, we ought to open ourselves up to more unorthodox views. Moreover, we have good reasons to adopt panpsychism; most importantly, we can account for the intimate bond between the mental and the physical. The distinction between conscious experience and physical entities is one of kind, not degree. Granting this dualistic understanding of the world, we should entertain the idea of conscious experience at the fundamental level, ...
Compaction-based concurrent error detection for digital circuits

We present a non-intrusive concurrent error detection (CED) method for combinational and sequential digital circuits. We analyze the optimal solution model and point out the limitations that prevent logic synthesis from yielding a minimal-cost monolithic CED implementation. We then propose a compaction-based alternative approach for restricted error models. The proposed method alleviates these limitations by decomposing the CED functionality into: compaction of the circuit outputs, prediction of the compacted responses, and comparison. We model the fault-free and erroneous responses as connected vertices in a graph and perform graph coloring in order to derive the compacted responses. The proposed method is first discussed within the context of combinational circuits, with zero detection latency, and subsequently extended to Finite State Machines (FSMs), with a constant detection latency of one clock cycle. Experimental results demonstrate that the proposed method achieves significant hardware reduction over duplication-based CED, while detecting all possible errors.
Silica-based nanoprobes for biomedical imaging and theranostic applications

Nanoparticle-based contrast agents are attracting a great deal of attention for various biomedical imaging and theranostic applications. Compared to conventional contrast agents, nanoparticles possess several potential advantages to improve in vivo detection and to enhance targeting efficiency. Silica-based nanoprobes can be engineered to achieve longer blood circulation times, specific clearance pathways, and multivalent binding. In this tutorial review, we summarize the latest progress on designing silica-based nanoprobes for imaging and theranostic applications. The synthesis of both solid silica and mesoporous silica nanoparticles is described, along with different approaches used for surface functionalization. Special emphasis is placed on the application of silica-based nanoprobes in optical, magnetic resonance, and multimodal imaging. The latest breakthroughs in the applications of silica nanoparticles as theranostic agents are also highlighted.
Ultrasound-Assisted Epoxidation of Olefins and α,β-Unsaturated Ketones over Hydrotalcites Using Hydrogen Peroxide

An efficient ultrasound-assisted epoxidation of olefins and α,β-unsaturated ketones over hydrotalcite catalysts in the presence of hydrogen peroxide and acetonitrile is described. This general and selective protocol is relatively fast and is applicable to a wide variety of substrates.
Prenatal seasonality, child growth, and schooling investments : evidence from rural Indonesia

This paper examines the impacts of prenatal conditions on child growth using recent data from Indonesia. There is seasonality in birth weight: this measure is significantly higher immediately after the main rice harvest in the country. The empirical results show that an increase in birth weight improves child growth outcomes as measured by the height and weight z-scores, as well as schooling performance as measured by age at start of schooling and number of grades repeated. The interactions of ecological variations affect early childhood human capital formation and can have long-term impacts on children's outcomes.
Flavor-changing neutral current constraints in topcolor-assisted technicolor

Abstract It is pointed out that flavor-changing neutral current processes (such as B - B mixing) can be sensitive to the dynamics of the topcolor models recently proposed by Hill [Phys. Lett. B 345 (1995) 483], unless at least some of the mixing angles between down-type quarks are suppressed. The flavor-changing processes are mediated by scalar bound states which are likely to be light as a result of the near critical dynamics of the b-quark sector. The consequences of the latter on the bottom quark mass are also briefly discussed.
Single shot amplitude and phase characterization of optical arbitrary waveforms.

Using a time-gated dual quadrature spectral interferometry technique, for the first time we demonstrate single-shot characterization of both spectral amplitude and phase of ~1THz bandwidth optical arbitrary waveforms generated from a 10 GHz frequency comb. Our measurements provide a temporal resolution of 1ps over a record length of 100ps. Single-shot characterization becomes particularly relevant when waveform synthesis operations are updated at the repetition rate of the comb allowing creation of potentially infinite record length waveforms. We first demonstrate unambiguous single shot retrieval using rapidly updating waveforms. We then perform additional single-shot measurements of static user-defined waveforms generated via line-by-line pulse shaping.
A thrust-sheet propulsion concept using fissionable elements

A space propulsion concept is proposed and analyzed which consists of a thin sheet coated on one side with fissionable material, so that nuclear power is converted directly into propulsive power. Thrust is available both from ejected fission fragments and from thermal radiation. Optimum thicknesses are determined for the active and substrate layers. This concept is shown to have potential mission capability (in terms of velocity increments) superior to that of all other advanced propulsion concepts for which performance estimates are available. A suitable spontaneously fissioning material such as Cf-254 could provide an extremely high-performance first stage beyond earth orbit. In contrast with some other advanced nuclear propulsion concepts, there is no minimum size below which this concept is infeasible.
Computation of the asymmetric vortex pattern for bodies of revolution

The three-dimensional flowfield surrounding a slender body of revolution at angle of attack was solved through numerical integration of the complete Navier-Stokes equations. The leeside vortex pattern was computed for two separate sets of conditions. First, a flowfield containing laterally symmetric vortices was computed for a three-caliber ogive cylinder at Mach number 1.98 and angle of attack of 20 deg. Second, a flowfield containing laterally asymmetric vortices was computed for a cone cylinder at Mach number 1.6 and angle of attack of 30 deg. Both cases used a laminar flow assumption. All results were obtained on a CRAY-1 computer utilizing MacCormack's algorithm as vectorized by Shang. The computed results compared favorably with the two sets of experimental data used, in that all the primary flow features were captured.
Self-similarity and coarsening of three dimensional particles on a one or two dimensional matrix

We examine the validity of the hypothesis of self-similarity in systems coarsening under the driving force of interface energy reduction in which three dimensional particles are intersected by a one or two dimensional diffusion matrix. In both cases, solute fluxes onto the surface of the particles, assumed spherical, depend on both particle radius and interparticle distance. We argue that overall mass conservation requires independent scalings for particle sizes and interparticle distances under magnification of the structure, and predict power law growth for the average particle size in the case of a one dimensional matrix (3D/1D), and a weak breakdown of self-similarity in the two dimensional case (3D/2D). Numerical calculations confirm our predictions regarding self-similarity and power law growth of average particle size with an exponent 1/7 for the 3D/1D case, and provide evidence for the existence of logarithmic factors in the laws of boundary motion for the 3D/2D case. The latter indicate a weak breakdown of self-similarity.
The Radical Consequences of Realistic Satellite Orbits for the Heating and Implied Merger Histories of Galactic Disks

Previous models of galactic disk heating in interactions invoke restrictive assumptions not necessarily valid in modern ΛCDM contexts: that satellites are rigid and orbits are circular, with slow decay over many orbital periods from dynamical friction. This leads to a linear scaling of disk heating with satellite mass: disk heights and velocity dispersions scale --> Msat/Mdisk. In turn, observed disk thicknesses present strong constraints on merger histories: the implication for the Milky Way is that z ~ 2, in conflict with cosmological predictions. More realistically, satellites merge on nearly radial orbits, and once near the disk, resonant interactions efficiently remove angular momentum while tidal stripping removes mass, leading to rapid merger/destruction in a couple of free-fall plunges. Under these conditions the proper heating efficiency is nonlinear in mass ratio, --> (Msat/Mdisk)2. We derive the scaling of disk scale heights and velocity dispersions as a function of mass ratio and disk gas content in this regime, and show that this accurately describes the results of simulations with appropriate live halos and disks. Under realistic circumstances, we show that disk heating in minor mergers is suppressed by an order of magnitude relative to the expectations of previous analyses. We show that the Milky Way disk could have experienced ~5-10 independent 1:10 mass ratio mergers since -->z ~ 2, in agreement with cosmological models. Because the realistic heating rates are nonlinear in mass, the predicted heating is dominated by the more stochastic, rare low mass ratio mergers, and the existence of populations with little or no thick disk does not require fundamental modifications to the cosmology. This also leads to important differences in the predicted isophotal shapes of bulge-disk systems along the Hubble sequence.
Proton-coupled electron transfer in [(bpy)2Mn(O)2Mn(bpy)2]3+

Etude des reactions electrochimiques du complexe de manganese sur une electrode de carbone a l'etat vitreux dans de l'acetonitrile
Asymmetric Catalysis with Chiral Porous Metal–Organic Frameworks

This paper provides a brief overview of recent progress in the design and synthesis of chiral metal–organic frameworks (CMOFs) and their applications in heterogeneous asymmetric catalysis. Catalytically active CMOFs can be synthesized using two distinct strategies, either by post-synthetic activation of pre-synthesized porous MOFs or by directly linking well-designed catalytically competent bridging ligands with metal ion or metal cluster nodes. Heterogeneous asymmetric catalysis with very high activity and enantioselectivity has been achieved with CMOFs. The intrinsic tunability of CMOFs promises to lead to the design and synthesis of a variety of practically useful heterogeneous asymmetric catalysts for many organic transformations.
GLOBULAR CLUSTERS IN THE OUTER GALACTIC HALO: AM-1 AND PALOMAR 14*

AM-1, at ~120 kpc, and Palomar 14 (Pal 14), at ~70 kpc, are two of the most distant Galactic globular clusters (GCs) known. We present Hubble Space Telescope Wide Field Planetary Camera 2 photometry of AM-1 and Pal 14 that reveals unprecedented depth and detail in the color-magnitude diagrams of these two clusters. Absolute and relative age measurements confirm that both are younger than the inner halo GC M 3 by 1.5-2 Gyr assuming all three clusters have similar compositions. Thus AM-1 and Pal 14 join Pal 3, Pal 4, and Eridanus as distant GCs with red horizontal branches (HBs) and young ages relative to the inner halo. Within the context of the entire body of research on the ages of second parameter GCs, the observed correlation between age and HB morphology suggests that age is the best candidate for the second parameter. However, this conclusion is tempered by the lack of precise chemical abundance determinations for a significant fraction of second parameter GCs.
Finite element solutions of Euler equations for lifting airfoils

Application d'une formulation de Clebsch des equations d'Euler aux ecoulements transsoniques autour de profils aerodynamiques
Extended gain bandwidth low ripple hybrid Raman-parametric amplifier design for PON applications

A hybrid Raman-OPA amplifier with 190 nm bandwidth, and &#60;4dB gain ripple is described. We also show that inclusion of the forth order dispersion coefficient is critical for the correct optimization of the gain bandwidth of the hybrid amplifier.
Agricultural Production Clubs: Viability and Welfare Implications

Consumers are in general less informed than producers about the quality of agricultural goods. To reduce he information gap, consumers can rely on standards (e.g., certification) that ensure quality and origin of the goods. These costly standards can be adopted by a group of producers of high-quality goods. We study the formation of such a group that we model as a club. We first investigate under what circumstances a club of a given size is desirable for producers, and for society. We then analyze the optimal size of the club when there exists a direct barrier to entry, and when there is no barrier. We find that for intermediate values of certification costs, the industry and a club of a given size of certified producers have divergent incentives. Furthermore, if barriers to entry are allowed, an optimal size of club exists, which allows some revelation of information. In the absence of barrier to entry, it is less likely that a club will emerge.
Numerical validation of a constitutive theory for an arbitrarily fractured solid

We have developed a general constitutive theory that estimates the effective elastic moduli of a cemented granular material by applying statistical mechanical averaging to a purely micromechanical model. We have also constructed a distinct element model of a cemented granular material, based on the same micromechanical model, which accounts for the elastic forces due to bonding between pairs of spherical particles, and which allows for the possibility of anisotropic damage to the bonds. In this paper, we use a model based on the distinct element method (DEM) to validate the predictions of the theory for various prescribed patterns of damage. In particular we impose several anisotropic patterns of damage on the bonds of a randomly generated assembly of particles. We then undertake numerical experiments, sending both p‐waves and s‐waves through the samples and measuring the wave velocities. The predictions of the theory for these velocities agree well with the results of the numerical model for a variety of damage patterns. We discuss the implications of our theory, as well as potential applications.
Neutron scattering studies of the high temperature spin dynamics of ferromagnetic materials

Abstract The two approaches to understanding the magnetic properties of materials are the localized Heisenberg model and the band theory of electrons. Neutron scattering results at elevated temperatures will be discussed in terms of these models for EuO, Gd and Ni. It is found that measurements near and above the Curie temperature T c are particulary useful for distinguishing between models for ferromagnetism in these materials.
Enough: The Failure of the Living Will

In pursuit of the dream that patients' exercise of autonomy could extend beyond their span of competence, living wills have passed from controversy to conventional wisdom, to widely promoted policy. But the policy has not produced results, and should be abandoned.
The Degrees of Freedom of MIMO Networks With Full-Duplex Receiver Cooperation but no CSIT

The question of whether the degrees of freedom (DoF) of multiuser networks can be enhanced even under isotropic fading and no channel state information or output feedback at the transmitters (CSIT) is investigated. Toward this end, the two-user multiple-input multiple-output (MIMO) broadcast and interference channels are studied with no side-information at the transmitters and with receivers equipped with full-duplex radios. The full-duplex feature allows for receiver cooperation because each receiver, in addition to receiving the signals sent by the transmitters, can also simultaneously transmit a signal in the same band to the other receiver. Unlike the case of MIMO networks with CSIT and full-duplex receivers, for which DoF are known, it is shown that for MIMO networks with no CSIT, full-duplex receiver cooperation is beneficial to such an extent that even the DoF region is enhanced. Indeed, for important classes of two-user MIMO broadcast and interference channels, defined by certain relationships on numbers of antennas at different terminals, the exact DoF regions are established. The key to achieving DoF-optimal performance for such networks are new retro-cooperative interference alignment schemes. Their optimality is established via the DoF analysis of certain genie-aided or enhanced version of those networks. Taken together, the results of this paper show that full-duplex receiver cooperation can recover the DoF lost due to lack of CSIT. In particular, even without CSI and/or output feedback, it has the potential of yielding most, if not all, the gains promised by delayed CSIT, or even Shannon, feedback.
On the feasibility of large-scale automated highways

We investigate the use of large-scale Automated Highway Systems, also called one-dimensional vehicle platoons, as a practical traffic mitigation solution. We review recent theoretical results related to vehicle platooning and discuss their implications on the scalability and safety of large-scale platoons. We also quantify the performance of different platoon control strategies through simulations that use realistic models of vehicle dynamics and sensor accuracy.
Discussion of “Compensation policy and discretionary disclosure”

Abstract Nagar et al. (J. Accounting Econom. 34 (2003)) posits that stock-based compensation motivates managers to increase public disclosure of their private information. The hypothesis is intriguing and new to the literature, and the findings are consistent with it. However, developing the hypothesis depends on some unsupported assumptions and the link between the hypothesis and the empirical evidence is indirect, raising concerns about the validity of the study's inferences about the effects on disclosure of stock-based compensation.
Molecular Electrostatic Potential Analysis for Enzymatic Substrates, Competitive Inhibitors, and Transition-State Inhibitors

Recent advances in the application of kinetic isotope effects to enzyme-catalyzed reactions have provided reliable information for enzymatic transition state structures. A method is presented for quantifying the similarity of substrates and inhibitors with their enzyme-stabilized transition states. On the basis of transition-state stabilization theory for enzymatic reactions, molecules most similar to the transition state structure bind with greatest affinity. Molecular similarity measures are applied to compare substrates, competitive inhibitors, and transition state inhibitors with the transition state structures stabilized by the enzymes AMP deaminase, adenosine deaminase, and AMP nucleosidase. (R)- and (S)-Coformycin 5‘-phosphate are inhibitors for AMP deaminase, with the R-species superior to its enantiomer. Formycin 5‘-phosphate 4-aminopyrazolo[3,4-d]pyrimidine-1-ribonucleotide, and tubercidin 5‘-phosphate inhibit AMP nucleosidase. The transition state for adenosine deaminase is analogous to that fo...
Erase rates in photorefractive materials with two photoactive species

Erase rates for uniformly illuminated refractive-index gratings are derived for a model of photorefractivity in which two photoactive ions participate as donors and acceptors. The model leads naturally to decay of gratings at two separate rates. In some conditions the amplitudes of the components that decay at each rate are nearly equal, while the rates are substantially different. These conditions should be readily observable in crystals with two photoactive species. In other conditions, one amplitude greatly exceeds the other or the time constants are nearly equal, and a single rate would be observed. The ratios of the rates and amplitudes are insensitive to erase irradiance but very sensitive to grating period and absorption cross section. Illustrative parameters for Bi12SiO20 suggest that if two photoactive species are present, two decay rates should be observable.
Solvent‐Free Photosynthesis of Cyclobutanes: Photodimerization of Crystalline Olefins

1 Introduction 2 Photodimerization of Cinnamic Acids: Emergence of Topochemical Postulates 3 Photodimerization of Coumarins, Styrylcoumarins and Benzylidenecyclopentanones 4 Reaction Cavity Concept: Role of Empty Space and Immediate Neighbors 5 Fine Tuning of Topochemical Postulates 6 Impact of Excitation on Molecular Geometry and Intermolecular Arrangement 7 Crystal Engineering 8 Does Dimerization Precede Geometric Isomerization? 9 Single Crystal to Single Crystal Photodimerization of Olefins 10 Concluding Remarks 11 Appendix: More Examples of Solid State Photodimerization of Olefins 12 Acknowledgment Keywords: olefin photodimerization and cyclobutanes in crystals; cinnamic acid photodimerization; reaction cavity concept; topochemical postulates; static concept of preorganization; crystal engineering; dimerization preceding geometric isomerization; single crystal to single crystal (SCSC)
Reaction of singlet oxygen with 2-cyclopenten-1-ones

Abstract The reaction of singlet oxygen with 2-cyclopenten-1-one derivatives is regioselective. Reactivity toward singlet oxygen is not solely determined by the conformation of the carbonyl group relative to the olefinic double bond, since even some s-trans derivatives are reasonably reactive.
Benzeneseleninic Anhydride Oxidation of 1,2-Diarylethanes and 1,2-Diarylethylenes to 1,2-Diaryldiketones.

Abstract 1,2-Diarylethanes and 1,2-diarylethylenes can be oxidized directly to 1,2-diaryldiketones in good yields by reaction with benzeneseleninic anyhdride (BSA) at 120 °C in chlorobenzene.
OBSERVATIONS OF THICK DISKS IN THE HUBBLE SPACE TELESCOPE ULTRA DEEP FIELD

The vertical profiles of chain and spiral galaxies in the Hubble Space Telescope Ultra Deep Field (UDF) are fit to sech2 functions convolved with stellar profiles in order to measure the disk scale heights z0 in four passbands. The bulge regions of the spiral galaxies are avoided. Photometric redshifts give absolute scales. The rms heights of the giant clumps in these galaxies are also measured. The results indicate that UDF disks are thick, with an average z0 = 1.0 ± 0.4 kpc. The ratio of radial exponential scale length to z0 is ~3 ± 1.5. The scale heights are only 20% larger than the radii of the giant star-forming clumps and a factor of ~10 larger than the rms clump deviations around the midplanes. This suggests that the clumps formed from midplane gas and dissolved to make the thick disks. Redshifted stellar population models suggest ages of ~1 Gyr and mass column densities from 4 to 40 M☉ pc-2. The UDF disks look like young versions of modern thick disks. This resemblance is difficult to understand if galaxies grow over time or if subsequent accretion of thin disks gravitationally shrinks the observed thick disks. More likely, high-redshift disks are thick because their mass column densities are low; a velocity dispersion of only 14 km s-2 reproduces the observed thickness. Modern thick disks require more heating at high redshift. This is possible if the gas that eventually makes the thin disk is in place before the youngest age of a modern thick disk, and if the existing stars are heated during the delivery of this gas.
The Timing of Redistribution

We investigate whether late redistribution programs that can be targeted toward low income families, but that may distort savings decisions, can �dominate� early redistribution programs that cannot be targeted as a result of information constraints. We use simple two-period overlapping generations models with heterogeneous agents under six policy regimes: a model calibrated to the U.S. economy (benchmark), two early redistribution (lump sum) regimes, two (targeted) late redistribution regimes, and finally a model without taxes and redistribution. Redistribution programs are financed by a labor tax on the young generation and a capital tax on the old generation. We argue that if the programs are small in size, late redistribution can dominate early redistribution in terms of welfare but not in terms of real output. Better targeting of low income households cannot completely offset savings distortions. In addition, we find that the optimal transfer and tax policy implies a capital tax of 100% and transfers exclusively to the young generation.
Consequences of Magnetic Field Structure for Heat Transport in Magnetohydrodynamics

Interfaces between hot and cold magnetized plasmas exist in various astrophysical contexts, for example, where hot outflows impinge on an ambient interstellar medium. It is of interest to understand how the structure of the magnetic field spanning the interface affects the temporal evolution of the temperature gradient. Here, we explore the relation between the magnetic field topology and the heat transfer rate by adding various fractions of tangled versus ordered field across a hot-cold interface that allows the system to evolve to a steady state. We find a simple mathematical relation for the rate of heat conduction as a function of the initial ratio of ordered-to-tangled field across the interface. We discuss potential implications for the astrophysical context of magnetized wind blown bubbles around evolved stars.
Stereoselective Synthesis of γ-Substituted (Z)-Allylic Boranes via Kinetically Controlled Hydroboration of Allenes with 10-TMS-9-borabicyclo[3.3.2]decane

Kinetically controlled hydroboration of allenes 8 and 14a−d with the readily accessible Soderquist borane 7, which is generated in situ from borohydride 6, constitutes a convenient and preparatively useful method for synthesis of (Z)-γ-(substituted)allylboranes 9 and 15a−d. These allylboranes undergo highly diastereo- (≥90: 10) and enantioselective (typically 89−96% e.e.) allylboration reactions with representative aldehydes to give syn-β-functionalized homoallylic alcohols.