cssi/SciSciGPT-SciSciNet huggingface dataset:
Hybrid Electrochemical/Chemical Synthesis of Quantum Dots

The "electrochemical/chemical method" (or "E/C method") is a new wet chemical method for synthesizing semiconductor quantum dots on graphite surfaces. The E/C synthesis of quantum dots composed of the generic semiconducting salt, MX, typically involves three steps: (1) electrochemical deposition of nanoparticles of the metal, M degrees, from a solution of metal ions, M(n)(+); (2) electrochemical oxidation of these metal particles to MO(n)()(/2), and; (3) displacement of the oxygen from MO(n)()(/2) using HX (for example) to yield nanoparticles of MX. This conversion from metal to metal oxide to metal salt occurs on a particle-by-particle basis; that is, each metal nanoparticle is converted into a semiconductor nanoparticle. E/C-synthesized beta-CuI and CdS quantum dots possess many of the attributes of quantum dots synthesized using molecular beam epitaxy, including epitaxial orientation on the graphite surface, a narrow size dispersion, and strong, particle size-tunable photoluminescence. However, the E/C method is faster, cheaper, and applicable to a greater number of materials.
Divergence, Big Time

ivergence in relative productivity levels and living standards is the dominant feature of modern economic history. In the last century, incomes in the "less developed" (or euphemistically, the "developing") countries have fallen far behind those in the "developed" countries, both proportionately and absolutely. I estimate that from 1870 to 1990 the ratio of per capita incomes between the richest and the poorest countries increased by roughly a factor of five and that the difference in income between the richest country and all others has increased by an order of magnitude.' This divergence is the result of the very different patterns in the long-run economic performance of two sets of countries. One set of countries-call them the "developed" or the "advanced capitalist" (Maddison, 1995) or the "high income OECD" (World Bank, 1995) -is easily, if awkwardly, identified as European countries and their offshoots plus Japan. Since 1870, the long-run growth rates of these countries have been rapid (by previous historical standards), their growth rates have been remarkably similar, and the poorer members of the group grew sufficiently faster to produce considerable convergence in absolute income levels. The other set of countries, called the "developing" or "less developed" or "nonindustrialized," can be easily, if still awkwardly, defined only as "the other set of countries," as they have nothing else in common. The growth rates of this set of countries have been, on average, slower than the richer countries, producing divergence in ' To put it another way, the standard deviation of (natural log) GDP per capita across all countries has increased between 60 percent and 100 percent since 1870, in spite of the convergence amongst the richest.
Semiclassical relativistic strings in S 5 and long coherent operators in N=4 SYM theory

We consider the low energy effective action corresponding to the 1-loop, planar, dilatation operator in the scalar sector of = 4 SU(N) SYM theory. For a general class of non-holomorphic ``long'' operators, of bare dimension L >> 1, it is a sigma model action with 8-dimensional target space and agrees with a limit of the phase-space string sigma model action describing generic fast-moving strings in the S 5 part of AdS 5 × S 5 . The limit of the string action is taken in a way that allows for a systematic expansion to higher orders in the effective coupling = λ/L 2. This extends previous work on rigid rotating strings in S 5 (dual to operators in the SU(3) sector of the dilatation operator) to the case when string oscillations or pulsations in S 5 are allowed. We establish a map between the profile of the leading order string solution and the structure of the corresponding coherent, ``locally BPS'', SYM scalar operator. As an application, we explicitly determine the form of the non-holomorphic operators dual to the pulsating strings. Using action-angle variables, we also directly compute the energy of pulsating solutions, simplifying previous treatments.
Convergent synthesis of potent COX-2 inhibitor inotilone

The first synthesis of potent COX-2 inhibitor inotilone is reported. The convergent route features a Mukaiyama aldol condensation that generates the target without the use of protecting groups or a separate dehydration step. The approach also highlights a superior regioselective preparation of 1-bromo-2,4-pentanedione involving a bis(silyl enol ether) and NBS.
Catalytic Conjugate Addition of Acyl Anion Equivalents Promoted by Fluorodesilylation

The conjugate addition of acyl anion equivalents derived from 2-silyl-1,3-dithianes to α,β-unsaturated ketones and esters has been achieved using a substoichiometric amount of TBAF. High yields and short reaction times are observed for the addition of aryl-1,3-dithianes to a variety of cyclic and acyclic α,β-unsaturated carbonyl acceptors. Observation of the reactive anion by 13C NMR spectroscopy and extension to an asymmetric variant is also presented.
Revealed Preference, Rational Inattention, and Costly Information Acquisition

We develop a revealed preference test for optimal acquisition of costly information. The test encompasses models of rational inattention, sequential signal processing, and search. We provide limits on the extent to which attention costs can be recovered from choice data. We experimentally elicit state dependent stochastic choice data of the form the tests require. In simple cases, tests con…rm that subjects adjust their attention in response to incentives as the theory dictates.
Solving games via three-valued abstraction refinement

Games that model realistic systems can have very large state-spaces, making their direct solution difficult. We present a symbolic abstraction-refinement approach to the solution of two-player games with reachability or safety goals. Given a reachability or safety property, an initial set of states, and a game representation, our approach starts by constructing a simple abstraction of the game, guided by the predicates present in the property and in the initial set. The abstraction is then refined, until it is possible to either prove, or disprove, the property over the initial states. Specifically, we evaluate the property on the abstract game in three-valued fashion, computing an over-approximation (the may states), and an under-approximation (the must states), of the states that satisfy the property. If this computation fails to yield a certain yes/no answer to the validity of the property on the initial states, our algorithm refines the abstraction by splitting uncertain abstract states (states that are may-states, but not must-states). The approach lends itself to an efficient symbolic implementation. We discuss the property required of the abstraction scheme in order to achieve convergence and termination of our technique.
Scaled sparse linear regression

SUMMARY Scaled sparse linear regression jointly estimates the regression coefficients and noise level in a linear model. It chooses an equilibrium with a sparse regression method by iteratively estimating the noise level via the mean residual square and scaling the penalty in proportion to the estimated noise level. The iterative algorithm costs little beyond the computation of a path or grid of the sparse regression estimator for penalty levels above a proper threshold. For the scaled lasso, the algorithm is a gradient descent in a convex minimization of a penalized joint loss function for the regression coefficients and noise level. Under mild regularity conditions, we prove that the scaled lasso simultaneously yields an estimator for the noise level and an estimated coefficient vector satisfying certain oracle inequalities for prediction, the estimation of the noise level and the regression coefficients. These inequalities provide sufficient conditions for the consistency and asymptotic normality of the noise-level estimator, including certain cases where the number of variables is of greater order than the sample size. Parallel results are provided for least-squares estimation after model selection by the scaled lasso. Numerical results demonstrate the superior performance of the proposed methods over an earlier proposal of joint convex minimization. Somekeywords:Convexminimization;Estimationaftermodelselection;Iterativealgorithm;Linearregression;Oracle inequality; Penalized least squares; Scale invariance; Variance estimation.
On the spherical symmetry of a static perfect fluid

A globally static space-time with asymptotically Euclidean behavior representing a finite body of a perfect fluid and a vacuum region is shown to be diffeomorphic to Euclidean space and its metric spherically symmetric whenever the magnitude of the gravitational field strength is only a function of the gravitational potential. Under some additional physical assumptions it is then proved that this spherically symmetric solution is not deformable, that is, does not admit a nontrivial first order perturbation that is also a static, asymptotically Euclidean perfect fluid with the same equation of state and the same central value of the pressure and the gravitational potential.
Global Implications of Self-Oriented National Monetary Rules

Author(s): Obstfeld, Maurice; Rogoff, Kenneth | Abstract: It is well known that if international linkages are relatively small, the potential gains to international monetary policy coordination are typically quite limited. But what if goods and financial markets are tightly linked? Is it then problematic if countries unilaterally design their institutions for monetary stabilization? Are the stabilization gains from having separate currencies largely squandered in the absence of effective international monetary coordination? We argue that under plausible assumptions the answer is no. Unless risk aversion is very high, lack of coordination in rule setting is a second-order problem compared to the overall gains from monetary policy stabilization.
Short-Duration Gamma-Ray Bursts

Gamma-ray bursts (GRBs) display a bimodal duration distribution with a separation between the short- and long-duration bursts at about 2 s. The progenitors of long GRBs have been identified as massive stars based on their association with Type Ic core-collapse supernovae (SNe), their exclusive location in star-forming galaxies, and their strong correlation with bright UV regions within their host galaxies. Short GRBs have long been suspected on theoretical grounds to arise from compact object binary mergers (neutron star–neutron star or neutron star–black hole). The discovery of short GRB afterglows in 2005 provided the first insight into their energy scale and environments, as well as established a cosmological origin, a mix of host-galaxy types, and an absence of associated SNe. In this review, I summarize nearly a decade of short GRB afterglow and host-galaxy observations and use this information to shed light on the nature and properties of their progenitors, the energy scale and collimation of the relativistic outflow, and the properties of the circumburst environments. The preponderance of the evidence points to compact object binary progenitors, although some open questions remain. On the basis of this association, observations of short GRBs and their afterglows can shed light on the on- and off-axis electromagnetic counterparts of gravitational wave sources from the Advanced LIGO/Virgo experiments.
Does Land Reform Matter? Some Experiences from the Former Soviet Union

There is still no evidence that new farming structures created in the process of land reform have achieved higher productivity than traditional farms. The most striking achievements of reform include a sharp reduction in state ownership of land and a substantial increase in the share of individual farming relative to collective agriculture. Among the rural population, independent private farmers appear to be more optimistic and economically better off than members of collective farm enterprises. This provides qualitative evidence of a positive impact of reform, as private farmers are direct participants in the process of reform, while rural residents who choose to remain in collectives largely shirk exposure to reform and continue to work within a traditional framework. Copyright 1998 by Oxford University Press.
Dynamic page migration in multiprocessors with distributed global memory

A mechanism called the pivot mechanism is introduced and described. It controls the dynamic migration of data pages between neighboring memory modules during program execution to improve the performance and programmability of multiprocessors with distributed global memory. The programmer or compiler is relieved from the data allocation task; moreover, because data allocation is dynamically modified to minimize communication traffic, algorithms with varying and unpredictable data access patterns can run efficiently. Flexible data migration serves the dual purpose of making algorithms the efficient machine-specific and making possible the efficient execution of algorithms for which a good static allocation is not possible. Simulation results based on a mesh-connected multiprocessor performing a matrix multiplication are presented. >
Sensitivity analysis of magnetic field sensors utilizing spin-dependent recombination in silicon diodes

Abstract An analysis of the magnetic field sensitivity that could be achieved in a sensor utilizing spin-dependent recombination (SDR) in silicon diodes is presented. Based on current theories of spin-dependent recombination and shot noise in diodes it is predicted that conventional silicon diodes may be used as detectors in a resonant magnetic field sensors with better than 3 μT resolution in a 1 Hz bandwidth – adequate for applications such as compassing, current sensing, position sensors and non-contact switches. A semiconductor device optimized for maximum SDR response will theoretically achieve a resolution on the order of 1 nT.
Low-temperature deformation mechanisms and their interpretation

Low-temperature deformation is characterized by heterogeneous strain in which the bulk of the material clearly retains its primary texture. Deformation is by grain-scale crystal plasticity, rotation, fracture, and pressure solution, and by transgranular mechanisms that crosscut numerous grains. The important low-temperature crystal-plastic features are twin lamellae, deformation bands, and undulatory extinction. Subgrain formation by recrystallization or crystal-plastic strain of more than 15% marks the upper limit of the low-temperature regime. Grain rotation may produce foliations in soft sediments or rocks. Microscopic to mesoscopic kinks and crenulations of bedding occur in soft clay and shale. Transgranular features include Luders' bands, cooling and desiccation cracks, joints, extension-fracture cleavage, clastic dikes, mineral-filled veins of several types, recrystallization/replacement veins, vein arrays, boudins, faults, stylolites, slickolites, solution cleavages that range from widely spaced to slaty and pencil cleavage. Pressure fringes form adjacent to relatively rigid grains and have fabrics analogous to those in veins. Faults include conjugate fault pairs (Andersonian faults) multiple simultaneous conjugates (Oertel faults), and Riedel shear-zone configurations. The sense of fault displacement is determined from bends, steps, trails, tails, and feather fractures. Superplasticity, especially if aided by diffusion in grain-boundary water, might be important at low temperatures. Fault textures are diagnostic of the environment of deformation but have yet to be uniquely correlated with the presence or absence of earthquakes. Riedel shears and pseudotachylite may form in earthquake source regions, although pseudotachylite is evidently rare in brittle fault zones. The best indicators of stress magnitudes are the critical' resolved shear stress for deformation twinning and the presence of tensile fractures. Strain magnitudes and stress and strain tensor orientations can be determined with a variety of methods that are based on mechanical twins, platy grain orientation, grain center distribution, and fault geometry and slip directions. Different deformation mechanism associations, expressed by the partitioning of the total strain into different mechanisms, are related to the ductility and environment of deformation. Deformation fronts separating different mechanism associations are defined on the basis of changes in the crystal-plastic component of strain.
Axial characterization of oxygen storage capacity in close-coupled lightoff and underfloor catalytic converters and impact of sulfur

Abstract The oxygen storage capacity of a 56,000 mile aged warmup and underfloor converter system was characterized as a function of axial location along the converters and compared with fresh samples having the same formulation. Measurements of oxygen storage were made using a titration technique and at conditions expected to be commonly encountered during OBD-II diagnosis of catalyst performance. Vehicle aging resulted in a dramatic loss of oxygen storage in the warmup converter presumably due to the severe thermal sintering, but the significant amount of phosphorus (P) and zinc (Zn) poison accumulation on this converter was found to impact oxygen storage minimally. This is in contrast to the measured impact of P and Zn deposition on warmed-up hydrocarbon conversion, which was found to be significant relative to the impact of thermal sintering. The underfloor converter was found to have retained nearly all of its original oxygen storage after vehicle aging, consistent with operation of this converter at moderate temperatures which do no result in severe thermal sintering of the noble metals and the ceria. The impact of sulfur on the oxygen storage of both warmup and underfloor converter sections was dramatic. Sections in the forward part of the warmup converter and in the front brick of the underfloor converter had relatively modest oxygen storage capacity which was almost completely blocked as the sulfur concentration reached 75–150 ppm (equivalent in gasoline). Other sections such as the rear of the warmup converter and the rear monolith of the underfloor converter had more oxygen storage capacity, which was significantly decreased as the sulfur concentration reached 150 ppm equivalent in fuel, and was approached complete loss near 500 ppm sulfur equivalent in fuel.
Improved distance M-ary (d,k) codes for high density recording

We consider the problem of coding for a high density recording channel. New recording media have been developed that support unsaturated, M-ary (M/spl ges/3) signaling. This paper is concerned with the analysis and design of M-ary runlength limited (RLL) codes for multi-amplitude, linear recording AWGN channels. The codes achieve the largest known coding density and have improved minimum distance over an ordinary Adler-Coppersmith-Hassner code designed via the state splitting algorithm. Comparisons are made with Ungerboeck-style trellis codes with comparable complexity. >
Comparative Evaluation of Fracture Mechanics Methodologies as Applied to Offshore Structural Design and Integrity Analyses

A comparative study was performed to evaluate the three most widely used elastic-plastic fracture mechanics methodologies. The three methods are the crack opening displacement (COD) design curve, which is widely used in the offshore industry, the British Central Electricity Generating Board (CEGB) R6 method, and the J -resistance curve method. Analyses of various flawed geometries based on these three methods were performed using consistent material fracture properties. The results of both the COD and R6 methods were compared with those of the J -resistance curve, which is the most rigorous of the three methods. The results of the COD concept, following BSI PD 6493 procedures, appear to be conservative at applied stress levels below 60 percent of the material yield strength and unconservative above this value. However, the results of the R6 method appear to be consistently conservative. The behavior of COD design curve solutions can be improved when the structural geometry and the actual stress-strain relationship are properly considered in the analyses.
Concerns about climate change and the role of fossil fuel use

The greenhouse effect, the ability of certain gases like carbon dioxide and water vapor to effectively trap some of the reemission of solar energy by the planet, is a necessary component to life on Earth; without the greenhouse effect, the planet would be too cold to support life. However, human activities are increasing the concentration of carbon dioxide and several other greenhouse gases, resulting in concerns about warming of the earth by 1–58C over the next century. Recent increases in global averaged temperature over the last decade already appear to be outside the normal variability of temperature changes for the last thousand years. A number of different analyses strongly suggest that this temperature increase is resulting from the increasing atmospheric concentrations of greenhouse gases, thus lending credence to the concerns about much larger changes in climate being predicted for the coming decades. It is this evidence that led the international scientific community through the Intergovernmental Panel on Climate Change Ž. Ž
Deformable contours: modeling and extraction

This paper considers the problem of modeling and extracting arbitrary deformable contours from noisy images. We propose a global contour model based on a stable and regenerative shape matrix, which is invariant and unique under rigid motions. Combined with Markov random field to model local deformations, this yields prior distribution that exerts influence over a global model while allowing for deformations. We then cast the problem of extraction into posterior estimation and show its equivalence to energy minimization of a generalized active contour model. We discuss pertinent issues in shape training, energy minimization, line search strategies, minimax regularization and initialization by generalized Hough transform. Finally, we present experimental results and compare its performance to rigid template matching. >
The Intermediate Phase in Ternary GexAsxSe1-2x Glasses

Melt-quenched AsxGexSe1–2x glasses over the composition range, 0 xc(2). Raman mode frequency of corner-sharing Ge(Se1/2)4 tetrahedra studied as a function of x, also shows three distinct regimes (or power-laws, p) that coincide with ΔHnr(x) trends. These regimes are identified with mechanically floppy (x xc(2)) phases. The Raman elasticity power-law in the intermediate phase, p1 = 1.04(3), and in the stressed rigid phase, p2= 1.52(5), suggest effective dimensionalities of d = 2 and 3 respectively.
Target zone models with stochastic realignments: an econometric evaluation

Abstract This paper provides empirical support for the second generation of target zone models with stochastic devaluation risk. I propose a simple non-linear framework with a time varying probability of exchange rate realignment. This model nests alternatives (i) with no devaluation risk; (ii) with constant devaluation risk; and (iii) the random walk. I reject these three in favor of a stochastic realignment model where devaluation risk varies with economic fundamentals. The model predicts 13 of 17 realignments for the Franc and Lira, including an out-of-sample episode in August 1993.
Management Fads, Pedagogies and Soft Technologies

We present a model for the diffusion of management fads and other technologies which lack clear objective evidence about their merits. The choices made by non-Bayesian adopters reflect both their own evaluations and the social in°uence of their peers. We show, both analytically and computationally, that the dynamics lead to outcomes that appear to be deterministic in spite of being governed by a stochastic process. In other words, when the objective evidence about a technology is weak, the evolution of this process quickly settles down to a fraction of adopters that is not predetermined. When the objective evidence is strong, the proportion of adopters is determined by the quality of the evidence and the adopters'competence.
Molecular electronics by the numbers

Molecules are an attractive option to develop nanoscale electronic devices. Experimental measurements of current-voltage characteristics of individual molecules have been possible for several years and have revealed rich structure and diverse behavior. This paper reviews recent theoretical work by the authors in which current-voltage characteristics of individual molecules are computed using a fully quantum-mechanical parameter-free method. The results provide detailed understanding of transport in molecules in the context of data and go further by obtaining information about the role of molecule-electrode contacts and predicting the behavior of three-terminal molecular devices and the factors that control their performance.
Baryogenesis, dark matter and the pentagon

We present a new mechanism for baryogenesis, which links the baryon asymmetry of the universe to the dark matter density. The mechanism arises naturally in the Pentagon model of TeV scale physics. In that context, it forces a re-evaluation of some of the assumptions of the model, and we detail the changes that are required in order to fit observations.
RESILIENT QUANTUM COMPUTATION : ERROR MODELS AND THRESHOLDS

Recent research has demonstrated that quantum computers can solve certain types of problems substantially faster than the known classical algorithms. These problems include factoring integers and certain physics simulations. Practical quantum computation requires overcoming the problems of environmental noise and operational errors, problems which appear to be much more severe than in classical computation due to the inherent fragility of quantum superpositions involving many degrees of freedom. Here we show that arbitrarily accurate quantum computations are possible provided that the error per operation is below a threshold value. The result is obtained by combining quantum error–correction, fault–tolerant state recovery, fault–tolerant encoding of operations and concatenation. It holds under physically realistic assumptions on the errors.
Reversed circular dichroism of isotropic chiral mediums with negative real permeability and permittivity

Negative real parts of the permittivity and permeability lead an isotropic chiral medium to exhibit circular dichroism that is reversed with respect to that exhibited by an identical medium, the real parts of which have positive permittivity and permeability. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 96–97, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10239
Sustaining and sharing economic growth in Tanzania

This book is designed to contribute to the government's thinking on how best to translate broad MKUKUTA (the government of Tanzania's National Strategy for Growth and Reduction of Poverty) policy objectives into practical tactics and programs well suited to Tanzania's economic priorities and to the removal of key institutional and infrastructure bottlenecks. The book aims to respond to three fundamental questions: (a) what factors explain Tanzania's recent acceleration in economic growth, (b) how well has the accelerated growth translated into reduced poverty, and (c) what needs to be done to sustain growth that is also pro-poor. This book focuses on three issues that are central to the success of Tanzania's poverty reduction efforts: What factors explain Tanzania's recent acceleration in economic growth? Has the accelerated economic growth translated into reduced poverty? What must be done to sustain economic growth that is pro-poor? The book presents evidence from the macroeconomic, sectoral, firm, and household levels that shed light on these questions. In addition, the book examines the effectiveness of measures that support the poor in efforts to accumulate human and physical capital, which would enhance their prospects of contributing to economic growth. Finally, it is important to mention that this book is a compilation of chapters written by authors from the African Development Bank (Peter Mwanakatwe), COWI Consultants (Kerstin Pfliegner), independent consultancies (Marianne Simonsen and Annabella Skof), and the World Bank (Jean-Eric Aubert, Vandana Chandra, Louise Fox, Henry Gordon, Johannes Hoogeveen, Pooja Kacker, Ying Li, Allister Moon, Philip Mpango, Ravi Ruparel, Anuja Utz, Robert J. Utz, and Michael Wong).
Modeling Labor Markets with Heterogeneous Agents and Matches

I present a matching model with heterogeneous workers, firms, and worker-fim matches. The model generalizes the seminal Jovanovic (1979) model to the case of heterogeneous agents. The equilibrium wage is linear in a person-specifi cc omponent, a firm-specific component, and a match specific component that varies with tenure. Under certain conditions, the equilibrium wage takes a simpler structure where the match specific component does not vary with tenure. I discuss fixed- and mixedeffect methods for estimating wage models with this structure on longitudinal linked employer-employee data. The fixed effect specification relies on restrictive identification conditions, but is feasible for very large databases. The mixed model requires less restrictive identification conditions, but is feasible only on relatively small databases. Both the fixed and mixed models generate empirical person, firm, and match effects with characteristics that are consistent with predictions from the matching model; the mixed model moreso than the fixed model. Shortcomings of the fixed model appear to be artifacts of the identification conditions.
A learning scheme for dynamic neural networks: equilibrium manifold and connective stability

Abstract Stability of recurrent neural network N: x i =x i + ∑ j=1 n e ij w ij 8 j (x i )+I i , i=1,2,…,n y i =g i (x i ) with learning rule L: e ij =uh ij (e,y,y ∗ ), i,j=1,2,…,n is analyzed using the concept of equilibrium manifold. We shall show that the concept provides an ideal setting for the formulation of a learning rule L that adaptively teaches network N to acquire a desired pattern y∗ as one of its asymptotically stable equilibria. Connective stability of a moving equilibrium in the composite two-time-scale system N & L is established for bounded interconnection weights eij wij and a sufficiently small learning rate μ. The conditions for connective stability, which are derived using the M-matrices and the concept of vector Liapunov functions, are suitable for studying the design trade-offs between the bounds on the nominal weights wij, the shape of the sigmoid function gi(xi), the learning rule h (e, y, y∗), and rate μ, as well as the size of the stability region containing y∗.
Estimation of an Occupational Choice Model when Occupations are Misclassified

This paper examines occupational choices using a discrete choice model that accounts for the fact that self-reported occupation data is measured with error. Despite evidence from validation studies which suggests that there is a substantial amount of measurement error in self-reported occupations, existing research has not corrected for classi…cation error when estimating models of occupational choice. This paper develops a panel data model of occupational choices that corrects for misclassi…cation in occupational choices and measurement error in occupation-speci…c work experience variables. The model is used to estimate the extent of measurement error in self-reported occupation data and quantify the bias that results from ignoring measurement error in occupation codes when
CTRW pathways to the fractional diffusion equation

Abstract The foundations of the fractional diffusion equation are investigated based on coupled and decoupled continuous time random walks (CTRW). For this aim we find an exact solution of the decoupled CTRW, in terms of an infinite sum of stable probability densities. This exact solution is then used to understand the meaning and domain of validity of the fractional diffusion equation. An interesting behavior is discussed for coupled memories (i.e., Levy walks). The moments of the random walk exhibit strong anomalous diffusion, indicating (in a naive way) the breakdown of simple scaling behavior and hence of the fractional approximation. Still the Green function P(x,t) is described well by the fractional diffusion equation, in the long time limit.
Supplier Evasion of a Buyer’s Audit: Implications for Motivating Supplier Social and Environmental Responsibility

Prominent buyers’ brands have been damaged because their suppliers caused major harm to workers or the environment, e.g., through a deadly factory fire or release of toxic chemicals. How can buyers motivate suppliers to exert greater care to prevent such harm? This paper characterizes a “backfiring condition” under which actions taken by prominent buyers (increasing auditing, publicizing negative audit reports, providing loans to suppliers) motivate a supplier to exert greater effort to pass the buyer’s audit by hiding information and less care to prevent harm. Intuitively appealing actions for a buyer (penalizing a supplier for harming workers or the environment, or for trying to deceive an auditor) may be similarly counterproductive. Contrary to conventional wisdom, squeezing a supplier’s margin (by reducing the price paid to the supplier or increasing wages for workers) motivates the supplier to exert greater care to prevent harm—under the backfiring condition. Whereas the necessary and sufficient cond...
Between Commonweal and Competition: Understanding the Governance of Public–Private Partnerships

The authors leverage insights and theories from the extensive interfirm (business-to-business, or B2B) alliance literature to explore the effect of the sectors of the partners on the governance of infrastructure public–private partnerships (PPPs) as compared with B2B alliances. Their analysis suggests that the sectors of the partners have an important impact on PPP governance, not only because the sector constrains the availability of some governance mechanisms but also because it makes alternative mechanisms available or relevant to the partners. Specifically, the authors predict that PPPs will avoid equity structures and will rely, instead, on less complete and more complex alliance contracts; a restricted scope of activities; and nonequity hostages, such as metagovernance mechanisms or stakeholder involvement. Contrasting with B2B alliances, their analysis also suggests that trust-based governance mechanisms will play a minimal role in the governance of PPPs.
Electro-optical modulation in graphene integrated photonic crystal nanocavities

We demonstrate high-contrast electro-optic modulation in a graphene integrated photonic crystal nanocavity, providing a modulation depth of more than 10 dB at telecom wavelengths. This work shows the feasibility of high-performance electro-optical modulators in graphene-based nanophotonics.
Efficient construction of cyclopenta[b]quinoline core of isoschizozygane alkaloids via intramolecular formal hetero-Diels-Alder reaction.

Acid-catalyzed condensation of aromatic amines with δ,e-unsaturated aldehydes, followed by intramolecular formal hetero Diels−Alder reaction, is described as a potential route to the cyclopenta[b]quinoline substructure of isoschizozygane alkaloids. Reactions are highly diastereoselective and produce adducts with up to four contiguous stereocenters.
Synthesis of polycyclic xanthenes and furans via palladium-catalyzed cyclization of polycyclic aryltriflate esters

Abstract Palladium-catalyzed cyclization of polycyclic aromatic o-(arylmethyl)phenol triflate esters takes place with unexpected sulfur–oxygen bond cleavage to furnish polycyclic xanthenes. These are the first examples of Pd-catalyzed cross-coupling of aryl triflate esters with arenes to form diaryl ethers. In contrast, analogous palladium-catalyzed cyclization of polycyclic o-(aryloxy)phenol triflate esters proceeds via a mechanism that involves conventional carbon–oxygen bond cleavage to furnish diaryl furans.
Parent stars of extrasolar planets – IX. Lithium abundances

We compare the Li abundances of a sample of stars with planets discovered with the Doppler method to a sample of stars without detected planets. We prepared the samples by combining the Li abundances reported in several recent studies in a consistent way. Our results confirm recent claims that the Li abundances of stars with planets are smaller than those of stars without planets near the solar temperature. We also find that the vsini and R' HK anomalies correlate with the Li abundance anomalies. These results suggest that planet formation processes have altered the rotation and Li abundances of stars that host Doppler-detected planets. We encourage others to test these findings with additional observations of Li in stars with temperatures between 5600 and 6200 K.
Cooperative Cashing? An Economic Analysis of Document Duplication in Cooperative Web Caching

Cooperative caching is a popular mechanism to allow an array of distributed caches to cooperate and serve each others' Web requests. Controlling duplication of documents across cooperating caches is a challenging problem faced by cache managers. In this paper, we study the economics of document duplication in strategic and nonstrategic settings. We have three primary findings. First, we find that the optimum level of duplication at a cache is nondecreasing in intercache latency, cache size, and extent of request locality. Second, in situations in which cache peering spans organizations, we find that the interaction between caches is a game of strategic substitutes wherein a cache employs lesser resources towards eliminating duplicate documents when the other caches employs more resources towards eliminating duplicate documents at that cache. Thus, a significant challenge will be to simultaneously induce multiple caches to contribute more resources towards reducing duplicate documents in the system. Finally, centralized decision making, which as expected provides improvements in average latency over a decentralized setup, can entail highly asymmetric duplication levels at the caches. This in turn can benefit one set of users at the expense of the other, and thus will be challenging to implement.
Compressible turbulence: Multi-fractal scaling in the transition to the dissipative regime

Abstract Multi-fractal scaling in the transition to the dissipative regime for fully-developed compressible turbulence is considered. The multi-fractal power law scaling behavior breaks down for very small length scales thanks to viscous effects. However, the effect of compressibility is found to extend the single-scaling multi-fractal regime further into the dissipative range. In the ultimate compressibility limit, thanks to the shock waves which are the appropriate dissipative structures, the single-scaling regime is found to extend indeed all the way into the full viscous regime. This result appears to be consistent with the physical fact that vortices become more resilient and stretch stronger in a compressible fluid hence postponing viscous intervention. The consequent generation of enhanced velocity gradients in a compressible fluid appears to provide an underlying physical basis for the previous results indicating that fully-developed compressible turbulence is effectively more dissipative than its incompressible counterpart.
Rational expectations, inflation and the nominal interest rate

Abstract There is a substantial empirical literature, beginning with Fama (1975), that utilizes regressions of the inflation rate in a given period on initial interest rates (or inflation differentials on the slope of the initial yield curve) to test the Fisher hypothesis and/or to provide forecasts of inflation. Both uses depend critically on the maintained hypothesis that asset market prices fully incorporate all relevant current information about future yields. This paper will investigate the plausibility of the rational expectations hypothesis for real returns in markets for one-period default-free bonds, will show that under normal macroeconomic assumptions it cannot be expected to hold, and will consider the consequences of its failure for the interpretation of empirical results.
A Commodity Solution Based High Data Rate Asynchronous Trigger System for Hadron Collider Experiments

We show how commodity CPU, networking and memory components greatly simplify a sophisticated trigger system designed for the demanding environment of a high data rate hadron collider experiment operating at 2times1032 cm-2 s-1. The trigger system is based on an 8-fold way, 3-level architecture capable of processing over 22 million data channels at a crossing rate of 2.5 MHz with a mean value of 6 interactions per crossing. Although originally designed for a B-physics experiment at the Tevatron, the flexible and highly scalable nature of the design should also be relevant to other next generation hadron collider experiments such as those at the LHC
OZONE/OXONE-MEDIATED OXIDATIONS OF AMINO AND O-BENZYLHYDROXYLAMINO SUGARS

A method for the preparation of C-methyl branched nitro sugars from the corresponding amino sugars by oxidation with mixed oxidants is described. Ozonolysis of the amino sugars in the presence of OXONE (potassium monopersulfate) and acetone (Bashir-Hashemi's procedure) gave nitro sugars in good yields. Oxidation of an O-benzylhydroxylamino sugar by this method resulted in deprotection and oxidation in a single step, giving the nitro sugar directly. The mixed oxidant method is experimentally simpler and more convenient to use than DMDO, which had been previously reported for the oxidation of amino sugars.
Stockpiled Forage Kochia to Maintain Beef Cows During Winter

Extending grazing into the winter, as opposed to feeding of harvested forages, can increase the sustainability of ranching in the western US. This study was conducted to determine the economic value of grazing stockpiled forage kochia (Kochia prostrata [L.] Scrad.) and crested wheatgrass (Agropyron desertorum [Fisch. Ex Link] Schultes) during the fall and winter. Changes in cow body weight, body condition score, and ultrasound backfat were compared for late-gestation cows grazing forage kochia–crested wheatgrass pastures vs. those fed alfalfa (Medicago sativa L.) hay in drylot. The study was conducted from early November to late January for 2 consecutive years near Promontory, Utah. Forage availability and nutritional quality were monitored throughout the experiment. Cows grazing stockpiled forages did not receive any protein or energy supplements. Forage kochia comprised approximately 70% of available forage, with November crude protein content of 116 and 76 g·kg−1 in years 1 and 2, respectively. Nutritional quality declined throughout the season, presumably mostly because of removal of higher-quality forage by preferential grazing as opposed to weathering. Averaged over years, cows grazing forage kochia–grass gained body weight (19 kg), increased in body condition (0.3 points), and maintained backfat thickness, finishing well within the range considered optimum for onset of calving and return to estrus. Pasture- vs. drylot-fed cows did not differ with regard to changes in body weight or body condition score. Both treatments increased backfat in year 1, when initial backfat was less than 0.5 cm, but both treatments resulted in loss of backfat in year 2, when initial backfat was greater than 1.0 cm. Grazing was more economical, costing $0.24·cow−1·d−1 less than feeding alfalfa hay in drylot. Forage kochia can be used on western rangelands to extend grazing into the fall and winter, thereby improving the profitability of beef production.
Estrogen attenuates P2X7-R-mediated apoptosis of uterine cervical cells by blocking calcium influx

Estrogen blocks apoptosis of human ectocervical epithelial cells by modulating P2X7/Ca2+ influx. The effect involves decreased Ca2+-influx and cytosolic-calcium-increase via ATP-activated P2X7 pores. This mechanism may have physiological significance in the human cervix, in-vivo, and the results suggest a physiological role for estrogen in the cervix as an anti-apoptotic factor.
Copper(I) iodide dimethyl sulfide catalyzed 1,4-addition of alkenyl groups from alkenyl-alkylzincate reagents

Abstract The presence of catalytic quantities of the copper(I) iodide dimethyl sulfide complex {(CuI)4(SMe2)3} with alkenyl-alkylzincate reagents allows for the complete chemoselective 1,4-addition of various alkenyl groups to a number of α,β-unsaturated carbonyl compounds in CH2Cl2 at +35 °C. The 1,4-addition of the mixed vinylzincate reagent is more efficient than the corresponding vinylzirconocene reagent in CH2Cl2 or THF. By employing CH2Cl2 as a medium, the asymmetric copper-catalyzed addition of the vinyl groups to α,β-unsaturated imides is facilitated by the presence of TMSOTf to give excellent yields and up to 95:5 diastereomeric ratios (dr).
ENDPOINT: WHEN ARTHROPLASTY IS NO LONGER AN OPTION

When is revision surgery contraindicated in the face of a failed total hip? Surgically indicated can be interpreted as a situation where the patient will benefit from a specific intervention, with sufficient likelihood, to warrant the risks of intervention. Contraindication connotes the opposite; the risks, or likelihood of the intervention9s failure to achieve the desired results outweigh the expected extent and likelihood of benefit. Contraindicated actually represents the end point of a complex decision making process which must be carried out by the practitioner in conjunction with the patient and may require the full range of the surgeons analytical, technical and communication skills. Most commonly the term means that the surgeon9s thinking has led to a belief that the patient will be better off without further surgery. Deciding to forego another revision usually means leaving the patient with a resection arthroplasty. Relative indications for resection, or even avoiding revision of a failed arthroplasty, are most commonly biological. In a healthy host, with a sterile but anatomically deficient bed with adequate soft tissue coverage, mechanical reconstruction capabilities and massive bulk allograft may allow reconstruction of almost any amount of tissue loss. Severe osteomyelitis or soft tissue infection, unmanageable for reasons, including but not limited to: chronic immune-suppression, mixed or resistant organisms or a life threatening sensitivity to antibiotics which may be required to treat the sepsis. More subjective factors, such as adequacy of soft tissue and bone stock, comorbid medical conditions or a patient9s desire to avoid additional surgery as well as costs must be considered. This decision may include dozens of other considerations, some of which may be considered pre-operatively and some which may only arise intra-operatively.
Copper-catalyzed amination of aromatic halides with 2-N,N-dimethylaminoethanol as solvent

A copper-catalyzed amination of aromatic halides under mild conditions using N,N-dimethylaminoethanol as solvent is described. We have studied this reaction in some detail varying the copper source, base, water content and other parameters including the scope of useful amine and aromatic halide structures. A variety of 4-halo-N,N-cycloalkylanilines and 2-N,N-cycloalkylaminothiophenes were synthesized for further elaboration into chromophores for optoelectronic applications.
Novel structure-defined chiral bis(oxazolinyl)thiophenes for Ru-catalyzed asymmetric cyclopropanation

Abstract The novel structures of sulfur-containing chiral bis(oxazoline) compounds which have been synthesized have been determined by X-ray crystal diffraction analyses. A high enantioselectivity (ee >99%) in the asymmetric cyclopropanation of diphenylethene with diazoester using the bis(oxazoline)-Ru(II) catalyst was obtained.