cssi/SciSciGPT-SciSciNet huggingface dataset:
A note on anomaly matching for finite density QCD

Abstract We note that the QCD phases at large finite density respect 't Hooft anomaly matching conditions. Specifically the spectrum of the light excitations possesses the correct quantum numbers required to obey global anomaly constraints. We argue that 't Hooft constraints can be used at finite density along with non perturbative methods to help selecting the correct phase.
Facile O-arylation of phenols and carboxylic acids.

A facile, transition-metal-free O-arylation procedure for phenols and aromatic carboxylic acids has been developed that affords good to excellent yields of arylated products under very mild reactio...
Gas-phase ion/ion reactions of peptides and proteins: acid/base, redox, and covalent chemistries

Gas-phase ion/ion reactions are emerging as useful and flexible means for the manipulation and characterization of peptide and protein biopolymers. Acid/base-like chemical reactions (i.e., proton transfer reactions) and reduction/oxidation (redox) reactions (i.e., electron transfer reactions) represent relatively mature classes of gas-phase chemical reactions. Even so, especially in regards to redox chemistry, the widespread utility of these two types of chemistries is undergoing rapid growth and development. Additionally, a relatively new class of gas-phase ion/ion transformations is emerging which involves the selective formation of functional-group-specific covalent bonds. This feature details our current work and perspective on the developments and current capabilities of these three areas of ion/ion chemistry with an eye towards possible future directions of the field.
Solids flow mapping in a gas–solid riser: Mean holdup and velocity fields

Abstract In this study, solids flow dynamics has been investigated in a 6 in. “cold-flow” circulating fluidized bed riser using non-invasive flow techniques. Gamma ray Computed Tomography (CT) has been used to measure the time-averaged cross-sectional solids holdup distribution. The time-averaged mean and fluctuating solids velocity fields have been quantified using the Computer Automated Radioactive Particle Tracking (CARPT) technique. Details of the experimental techniques, protocol of implementation and data analysis are discussed. The experimental studies examine operating conditions in fast fluidization and dilute phase transport regimes. Comparative and symbiotic analyses of the results obtained from CARPT and CT have been used to develop a coherent picture of the solids flow field. In addition, this work also demonstrates the power of CARPT and CT as flow mapping techniques in studying highly turbulent and opaque multiphase systems.
Numerical Simulation of Low-Pressure Turbine Blade Separation Control

Low-pressure turbines are a common and important element of many modern jet engines. Any performance improvement will lead to net savings in aircraft operating costs. At low operating Reynolds numbers or for reduced stage solidities laminar separation from the constituent blades can noticeably deteriorate overall engine performance. Under such conditions active control of laminar separation may eliminate or reduce associated losses resulting in increased engine performance. A high-order-accurate finite volume Navier-Stokes code for investigating separation control for the PackB blade geometry at a Reynolds number based on axial chord of 25,000 was employed. For this Reynolds number laminar separation was observed in the experiments. First, a grid resolution study for the uncontrolled flow was carried out, which shows grid convergence for our simulations. Then separation control by pulsed vortex generator jets was investigated. It is shown how this control results in an earlier transitioning of the flow and the introduction of spanwise coherent structures. The increased wall-normal mixing associated with these two mechanisms results in an effective separation control. An even more efficient separation control can be accomplished by harmonic blowing through a slot. The astounding effectiveness of the latter control scheme is attributed to an amplification of the disturbance input through a hydrodynamic instability mechanism and to the suppression of three-dimensional structures, which weaken the spanwise structures. Finally, separation control by streamwise vortices that were generated by volume forces was investigated. As the flow does not amplify such structures the energy input required for accomplishing an effective control was found to be large compared with the other flow control techniques. Because the structures are steady they can, however, likely be generated with passive devices such as vortex generators.
Giant magnetoresistance materials and their potential as read head sensors

The physical origins of the giant magnetoresistance (GMR) phenomenon is briefly reviewed, and the magnitudes of the GMR ratios in multilayers, spin values, and granular alloys is reviewed. It is pointed out that, though spin valves have been the leading candidate for sensor materials, the maximum values of the sensor sensitivity dR/dH achieved in spin valves are modest. Multilayers can have enormous values of /spl Delta/R/R, but are not presently realistic sensor candidates because of their large saturation fields. Arguments are made that interlayer exchange may be manipulable and attractive sensor arrays synthesized. Recent developments in pancake/multilayer granular alloys are presented, NiFe-Ag systems which display a small saturation field and very attractive values of dR/dH. The conclusion is drawn that GMR sensors will be important in read head technology in the near future. >
Testing for the Gaussian nature of cosmological density perturbations through the three-point temperature correlation function.

One of the crucial aspects of density perturbations that are produced by the standard inflation scenario is that they are Gaussian where seeds produced by topological defects tend to be non-Gaussian. The three-point correlation function of the temperature anisotropy of the cosmic microwave background radiation (CBR) provides a sensitive test of this aspect of the primordial density field. In this paper, this function is calculated in the general context of various allowed non-Gaussian models. It is shown that the Cosmic Background Explorer and the forthcoming South Pole and balloon CBR anisotropy data may be able to provide a crucial test of the Gaussian nature of the perturbations.
Line Emission from Gas in Optically Thick Dust Disks around Young Stars

Wepresent self-consistent models of gas in optically thick dustydisks and calculate its thermal, density, and chemical structure. The models focus on an accurate treatment of the upper layers where line emission originates and at radii k0.7 AU. Although our models are applicable to stars of any mass, we present here only results around � 1 M� stars where we have varied dustproperties, X-ray luminosities, and UV luminosities. Weseparately treat gas and dust thermal balance and calculate line luminosities at infrared and submillimeter wavelengths from all transitions originating in the predominantly neutral gas that lies below the very tenuous and completely ionized surface of the disk. We find that the [Ar ii ]7 � m, [Ne ii] 12.8 � m, [Fe i ]2 4� m, [S i ]2 5� m, [Fe ii ]2 6� m, [Si ii ]3 5� m, [O i ]6 3� m, and purerotationallinesof H2and CO canbequitestrongandaregoodindicatorsof thepresenceanddistributionof gasin disks. Water is an important coolant in the disk, and many water emission lines can be moderately strong. Current and futureobservationalfacilitiessuchastheSpitzerSpaceTelescope,HerschelSpaceObservatory,andSOFIAarecapable of detecting gas emission from young disks. We apply our models to the disk around the nearby young star, TW Hya, and find good agreement between our model calculations and observations. We also predict strong emission lines from the TW Hya disk that are likely to be detected by future facilities. We suggest that the gas disk around TW Hya may be truncated to � 120 AU, compared to its dust disk of 174 AU. We speculate that photoevaporation due to the strong stellar FUV field from TW Hya is responsible for the gas disk truncation. Subject headingg infrared: ISM — line: formation — planetary systems: protoplanetary disks — radiative transfer
Rhenium catalyzed sulfurization of phosphorus(III) compounds with thiiranes: New reagents for phosphorothioate ester synthesis

Abstract A new method for the mild sulfurization of phosphorus(III) compounds with thiiranes catalyzed by ReOCl 3 (PPh 3 ) 2 ( I ) or ReOCl 3 (SMe 2 )OPPh 3 ) ( II ) is reported. The novel catalytic sulfur transfer reactions are rapid and occur efficiently under ambient conditions in organic solvents. This methodology enabled propylene sulfide to be used as a sulfurizing agent for the synthesis of a protected nucleotide phosphorothioate ester.
Measurement of the Lamb shift in lithiumlike uranium (U89

The 2{sup 2}{ital P}{sub 1/2}-2{sup 2}{ital S}{sub 1/2} (lowest-excited-state to ground-state) energy splitting in lithiumlike uranium, which has large quantum-electrodynamic corrections, has been measured using Doppler-tuned spectrometry. Our result, 280.59{plus minus}0.10 eV, is more precise than current theory and is an 80-fold improvement over the previous most precise measurement of the Lamb shift in (heliumlike) uranium.
Injunctive and reverse settlements in competition-blocking litigation

We distinguish standard settlements, in which the status quo is preserved, and injunctive settlements, which prohibit the defendant’s activity. The reverse (payment) settlement is a special type of injunctive settlement. We examine the divergence between private and social incentives to settle and policies that would minimize socially undesirable injunctive and reverse settlements (e.g., banning reverse settlements). The results are applied to competition-blocking litigation, such as patent infringement and antidumping.
Extending the constraint propagation of intervals

We show that the usual notion of constraint propagation is but one of a number of similar inferences useful in quantitative reasoning about physical objects. These inferences are expressed formally as rules for the propagation of «labeled intervals» through equations. We prove the rules' correctness and illustrate their utility for reasoning about objects (such as motors or transmissions) which assume a continuum of different states. The inferences are the basis of a «mechanical design compiler», which has correctly produced detailed designs from «high level» descriptions for a variety of power transmission and temperature sensing systems
Establishing Key Reservoir Parameters with Diagnostic Fracture Injection Testing

Diagnostic fracture injection testing (DFIT) is an invaluable tool for evaluating reservoir properties in unconventional formations. The test comprises injection of water over a short time, starting a fracture at the end of a well’s horizontal section, followed by a long shut-in period. Analysis of the falloff data with the G-function plot reveals the fracture-closure pressure, and the fracture pseudolinear-flow period. In most tests, wellhead-pressure (WHP) measurements are used because of cost considerations. A wellbore-heat-transfer model is used to allow conversion of WHP to bottomhole pressure (BHP) by accounting for changing fluid density and compressibility along the wellbore. This model, in turn, allowed us to assess the quality of solutions generated with the WHP data. For DFIT analysis, we adapted the modified-Hall plot for the injection period, whereas both the pressure-derivative and G-function plots were used for the analysis of falloff data. The derivative signature of the modified-Hall plot allows unambiguous estimation of the fracturebreakdown pressure ( pfb) during the injection period. As expected, the pfb always turns out to be higher than the fracture-closure pressure ( pfc), estimated with the two methods during pressure falloff, thereby instilling confidence in the solutions obtained. A statistical design of experiments with coupled geomechanical/fluid-flow simulation capabilities showed that the formation permeability is by far the most important variable controlling the fracture-closure time. Mechanical rock properties, such as Young’s modulus of elasticity and the Poisson’s ratio, play minor roles. In microdarcy formations, a longitudinal fracture takes much longer to close than a transverse fracture.
Crystal structures, charge and oxygen-vacancy ordering in oxygen deficient perovskites SrMnOx (x<2.7)

Bulk SrMnO {sub x} samples with oxygen contents 2.5{<=}x<2.7 have been studied using a combination of neutron time-of-flight and high-energy high-resolution synchrotron X-ray diffraction measurements along with thermogravimetric analysis. We report the identification and characterization of two new oxygen-vacancy ordered phases, Sr{sub 5}Mn{sub 5}O{sub 13} (SrMnO{sub 2.6}-tetragonal P4/m a=8.6127(3) A, c=3.8102(2) A) and Sr{sub 7}Mn{sub 7}O{sub 19} (SrMnO{sub 2.714}-monoclinic P2/m a=8.6076(4) A, b=12.1284(4) A, c=3.8076(2) A, {gamma}=98.203(2){sup o}). The nuclear and magnetic structures of Sr{sub 2}Mn{sub 2}O{sub 5} are also reported (SrMnO{sub 2.5} nuclear: orthorhombic Pbam, magnetic: Orthorhombic Ay type P{sub c}bam with c {sub M}=2c). In the three phases, oxygen-vacancies are ordered in lines running along one of the (100) directions of the parent cubic perovskite system. Oxygen-vacancy ordering allows the charge and orbital ordering of the Mn{sup 3+} and Mn{sup 4+} cations in the new phases. - Graphical abstract: The structures of Sr{sub 5}Mn{sub 5}O{sub 13} and Sr{sub 7}Mn{sub 7}O{sub 19} (shown) were determined using synchrotron X-rays and neutron time-of-flight powder diffraction and the Rietveld method on multiphase bulk samples. Charge, orbital and oxygen vacancy-ordering has been observed in the novel compounds where Mn{sup 4+} octahedra and Mn{sup 3+} pyramids are linked through the corners leaving lines ofmore » vacant oxygen sites lying along the c-axis.« less
Sampling methods and admissions of sexual aggression among college men

Most research on the causes of the sexually aggressive behavior of nonincarcerated men uses college student samples. To examine potential biases associated with different sampling methods, we compare self‐reports of male sexual aggression from studies using random samples to those using classroom volunteers. Fewer men in the random samples admitted to sexual aggression. Several explanations for these results are considered, and an experiment is proposed to examine biases to be expected from these two methods.
A note on nonwhite migration, welfare levels, and the political process

This empirical note finds that nonwhite migration is positively and significantly affected by welfare levels and that welfare levels in turn are positively and significantly affected by nonwhite migration. Thus, this two stage least squares analysis of 1960-1970 net interstate migration lends support to the hypothesis that while nonwhite families are attracted for one reason or another to those states having higher welfare benefit levels per recipient on the one hand, through the political (voting) process they effectively exert pressures to raise welfare levels per recipient on the other hand.
The smoothing of pension expenses: a panel analysis

The main purpose of this paper is to utilize recent developments in panel data techniques to evaluate whether the smoothing of pension expenses is neutral in its long-term effect on reported earnings. Adopting a long-term perspective, the empirical analysis also identifies sources of potential deviations. Results suggest that the current smoothing mechanism tends to induce significant biases in the recognized pension expenses. For a majority of the sample firms, the tendency is to overstate the sponsoring firms’ earnings in the long run. To a large extent, such biases reflect the combination of both ineffective amortization of the deferred gains and losses and questionable latitude in pension rate discretions.
Collective Bargaining and the Interindustry Wage Structure: International Evidence

This paper studies collective bargaining and industry wage levels using microdata and quantile regression techniques for the United States, Britain, West Germany, Austria, Sweden and Norway for the 1980s. The United States has higher industry wage differentials and union wage effects than other countries, with particularly large impacts at the bottom of the distribution. European wage structures are more compressed at the bottom for both nonunion and union workers relative to the United States, with larger differences for nonunion workers. These findings suggest more coordination, contract extension and spillover to nonunion workers, and more binding industry wage floors outside the United States.
The Formation of Massive Stars from Turbulent Cores

Observations indicate that massive stars in the Galaxy form in regions of very high surface density, � � 1 gc m � 2 . Clusters containing massive stars and globular clusters have a column density comparable to this. The total pressure in clouds of such a column density is P=k � 10 8 10 9 Kc m � 3 , far greater than that in the diffuse interstellar medium or the average in giant molecular clouds. Observations show that massive-star– forming regions are supersonically turbulent, and we show that the molecular cores out of which individual massive stars form are as well. The protostellar accretion rate in such a core is approximately equal to the instantaneous mass of the star divided by the free-fall time of the gas that is accreting onto the star, as described by Stahler, Shu, & Taam. The star formation time in this turbulent core model for massive-star formation is several times the mean free-fall time of the core out of which the star forms but is about equal to that of the region in which the core is embedded. The high densities in regions of massive-star formation lead to typical timescales for the formation of a massive star of about 10 5 yr. The corresponding accretion rate is high enough to overcome the radiation pressure due to the luminosity of the star. For the typical case we consider, in which the cores out of which the stars form have a density structure � / r � 1:5 , the protostellar accretion rate grows with time as _ m� / t. We present a new calculation of the evolution of the radius of a protostar and determine the protostellar accretion luminosity. At the high accretion rates that are typical in regions of massive-star formation, protostars join the main sequence at about 20 M� . We apply these results to predict the properties of protostars thought to be powering several observed hot molecular cores, including the Orion hot core and W3(H2O). In the appendices we discuss the pressure in molecular clouds and argue that ‘‘ logatropic ’’ models for molecular clouds are incompatible with observation. Subject headings: hydrodynamics — ISM: clouds — stars: formation — turbulence
The equivalence of viscosity and distributional subsolutions for convex subequations — a strong Bellman principle

There are two useful ways to extend nonlinear partial differential inequalities of second order beyond the class of C2 functions: one uses viscosity theory and the other uses the theory of distributions. This paper considers the convex situation where both extensions can be applied. The main result is that under a natural “second-order completeness” hypothesis, the two sets of extensons are isomorphic, in a sense that is made precise.
Tedanolide and the evolution of polyketide inhibitors of eukaryotic protein synthesis

Covering: up to March 2008 This Highlight covers the chemical and biological studies regarding a set of polyketide inhibitors of eukaryotic protein synthesis related to the marine-derived cytotoxic agent tedanolide.
A bound for the number of vertices of a polytope with applications

We prove that the number of vertices of a polytope of a particular kind is exponentially large in the dimension of the polytope. As a corollary, we prove that an n-dimensional centrally symmetric polytope with O(n) facets has {ie1-1} vertices and that the number of r-factors in a k-regular graph is exponentially large in the number of vertices of the graph provided k?2r+1 and every cut in the graph with at least two vertices on each side has more than k/r edges.
Coherence of Countably Many Bets

De Finetti’s betting argument is used to justify finitely additive probabilities when only finitely many bets are considered. Under what circumstances can countably many bets be used to justify countable additivity? In this framework, one faces issues such as the convergence of the returns of the bet. Generalizations of de Finetti’s (Fundam Math 17:298–329, 1931) argument depend on what types of conditions on convergence are required of the bets under consideration. Two new such conditions are compared with others presented in the literature.
An Exactly Solvable Model of Random Site-Specific Recombinations

Cre-lox and other systems are used as genetic tools to control site-specific recombination (SSR) events in genomic DNA. If multiple recombination sites are organized in a compact cluster within the same genome, a series of random recombination events may generate substantial cell specific genomic diversity. This diversity is used, for example, to distinguish neurons in the brain of the same multicellular mosaic organism, within the brainbow approach to neuronal connectome. In this paper, we study an exactly solvable statistical model for SSR operating on a cluster of recombination sites. We consider two types of recombination events: inversions and excisions. Both of these events are available in the Cre-lox system. We derive three properties of the sequences generated by multiple recombination events. First, we describe the set of sequences that can in principle be generated by multiple inversions operating on the given initial sequence. We call this description the ergodicity theorem. On the basis of this description, we calculate the number of sequences that can be generated from an initial sequence. This number of sequences is experimentally testable. Second, we demonstrate that after a large number of random inversions every sequence that can be generated is generated with equal probability. Lastly, we derive the equations for the probability to find a sequence as a function of time in the limit when excisions are much less frequent than inversions, such as in shufflon sequences.
A ONE‐SECTOR NEOCLASSICAL GROWTH MODEL WITH ENDOGENOUS RETIREMENT

This paper extends Diamond’s overlapping generations model by allowing the agents to make the retirement decision. Earning a higher wage income when young not only enables the agents to save more. It also induces more agents to retire early and gives an additional incentive to save more for retirement. This leads to a higher capital–labour ratio in the following period and hence the next generation of agents earns a higher wage income when young. Due to this positive feedback mechanism, endogenous retirement magnifies the persistence of growth dynamics and even generates multiple steady-states for empirically plausible parameter values.
On Curve Veering and Flutter of Rotating Blades

The eigenvalues of rotating blades usually change with rotation speed according to the Stodola-Southwell criterion. Under certain circumstances, the loci of eigenvalues belonging to two distinct modes of vibration approach each other very closely, and it may appear as if the loci cross each other. However, our study indicates that the observable frequency loci of an undamped rotating blade do not cross, but must either repel each other (leading to “curve veering”), or attract each other (leading to “frequency coalescence”). Our results are reached by using standard arguments from algebraic geometry—the theory of algebraic curves and catastrophe theory. We conclude that it is important to resolve an apparent crossing of eigenvalue loci into either a frequency coalescence or a curve veering, because frequency coalescence is dangerous since it leads to flutter, whereas curve veering does not precipitate flutter and is, therefore, harmless with respect to elastic stability.
Effects of High-Speed Tunnel Noise on Laminar-Turbulent Transition

It is well known that the high levels of noise present in conventional hypersonic ground-test facilities cause transition to occur earlier than in e ight. Flight measurements of incoming noise are reviewed and compared with measurements in ground-test facilities, of both conventional and quiet design, at hypersonic and high supersonic speeds. The low noise present in e ight is apparently the reason for the very large transition Reynolds numbers sometimes measured in e ight, when roughness, crosse ow, and other factors are controlled. Design will usually involve consideration of the trend in transition when a parameter is varied. The effect of facility noise on these trends is reviewed. In some cases, the trend of conventional-tunnel data is opposite to the trend in quiet-tunnel data. Thus, transition measurements in conventional ground-test facilities are not reliable predictors of e ight performance, except perhaps in special cases.
SURFACE-MEDIATED HIGHLY EFFICIENT OXIDATION OF ALCOHOLS BY BISMUTH NITRATE

Montmorillonite impregnated with bismuth nitrate was found to be an excellent reagent for the oxidation of a variety of alcohols in excellent yield.
Increased microstructural variability is associated with decreased structural strength but with increased measures of structural ductility in human vertebrae.

The lack of accuracy in the prediction of vertebral fracture risk from average density measurements, all external factors being equal, may not just be because bone mineral density (BMD) is less than a perfect subrogate for bone strength but also because strength alone may not be sufficient to fully characterize the structural failure of a vertebra. Apart from bone quantity, the regional variation of cancellous architecture would have a role in governing the mechanical properties of vertebrae. In this study, we estimated various microstructural parameters of the vertebral cancellous centrum based on stereological analysis. An earlier study indicated that within-vertebra variability, measured as the coefficient of variation (COV) of bone volume fraction (BV/TV) or as COV of finite element-estimated apparent modulus (E FE ) correlated well with vertebral strength. Therefore, as an extension to our earlier study, we investigated (i) whether the relationships of vertebral strength found with COV of BV/TV and COV of E FE could be extended to the COV of other microstructural parameters and microcomputed tomography-estimated BMD and (ii) whether COV of microstructural parameters were associated with structural ductility measures. COV-based measures were more strongly associated with vertebral strength and ductility measures than average microstructural measures. Moreover, our results support a hypothesis that decreased microstructural variability, while associated with increased strength, may result in decreased structural toughness and ductility. The current findings suggest that variability-based measures could provide an improvement, as a supplement to clinical BMD, in screening for fracture risk through an improved prediction of bone strength and ductility. Further understanding of the biological mechanisms underlying microstructural variability may help develop new treatment strategies for improved structural ductility.
Simple and nearly optimal multi-item auctions

We provide a Polynomial Time Approximation Scheme (PTAS) for the Bayesian optimal multi-item multi-bidder auction problem under two conditions. First, bidders are independent, have additive valuations and are from the same population. Second, every bidder's value distributions of items are independent but not necessarily identical monotone hazard rate (MHR) distributions. For non-i.i.d. bidders, we also provide a PTAS when the number of bidders is small. Prior to our work, even for a single bidder, only constant factor approximations are known.Another appealing feature of our mechanism is the simple allocation rule. Indeed, the mechanism we use is either the second-price auction with reserve price on every item individually, or VCG allocation with a few outlying items that requires additional treatments. It is surprising that such simple allocation rules suffice to obtain nearly optimal revenue.
Unitary representations and theta correspondence for type I classical groups

In this paper, we discuss the positivity of the Hermitian form ð; Þ p introduced by Li in Invent. Math. 27 (1989) 237–255. Let ðG1; G2Þ be a type I dual pair with G1 the smaller group. Let p be an irreducible unitary representation in the semistable range of yðMG1; MG2Þ (see Communications in Contemporary Mathematics, Vol. 2, 2000, pp. 255–283). We prove that the invariant Hermitian form ð; Þp is positive semidefinite under certain restrictions on the size of G2 and a mild growth condition on the matrix coefficients of p: Therefore, if ð; Þp does not vanish, yðMG1; MG2ÞðpÞ is unitary. Theta correspondence over R was established by Howe in (J. Amer. Math. Soc. 2 (1989) 535–552). Li showed that theta correspondence preserves unitarity for dual pairs in stable range. Our results generalize the results of Li for type I classical groups (Invent. Math. 27 (1989) 237). The main result in this paper can be used to construct irreducible unitary
The influence of dental unit waterline cleaners on composite-to-dentin bond strengths

ABSTRACT Background One approach to controlling dental unit waterline (DUWL) contamination by microorganisms is the addition of chemical cleaners to the treatment water. Yet, there is concern that these cleaners might affect the bonding of resin-based composites to enamel and dentin. The authors evaluated the influence of DUWL cleaners on composite-to-dentin bond strengths. Methods The authors tested the strength of resin-based composite bonded to dentin in specimens treated with distilled water (control) or one of four cleaners. They tested a total-etch adhesive, a self-etching primer/adhesive and an experimental self-etching primer/adhesive. The authors stored the specimens for 24 hours at 37 C and tested them to determine their bond strengths. Results The mean shear bond strengths (SBSs) varied according to the cleaner and adhesive used, ranging from 14.7 to 21.9 megapascals. However, the authors found no statistically significant differences and/or interactions between mean SBSs of specimens treated with the various DUWL cleaners and adhesives ( P ≥ .05). Conclusions The tested DUWL cleaners did not significantly influence composite-to-dentin bond strengths for the total-etch adhesive and self-etching primer/adhesives used in this study. Clinical Implications The conclusions imply that bonding of resin-based composites to dentin is not affected by the cleaners tested when they are used to treat DUWL contamination.
Sticky Information and the Locus of Problem Solving: Implications for Innovation

To solve a problem, needed information and problem-solving capabilities must be brought together. Often the information used in technical problem solving is costly to acquire, transfer, and use in a new location-is, in our terms, "sticky." In this paper we explore the impact of information stickiness on the locus of innovation-related problem solving. We find, first, that when sticky information needed by problem solvers is held at one site only, problem solving will be carried out at that locus, other things being equal. Second, when more than one locus of sticky information is called upon by problem solvers, the locus of problem solving may iterate among these sites as problem solving proceeds. When the costs of such iteration are high, then, third, problems that draw upon multiple sites of sticky information will sometimes be "task partitioned" into subproblems that each draw on only one such locus, and/or, fourth, investments will be made to reduce the stickiness of information at some locations. Information stickiness appears to affect a number of issues of importance to researchers and practitioners. Among these are patterns in the diffusion of information, the specialization of firms, the locus of innovation, and the nature of problems selected by problem solvers.
Analysis of dynamic linear and non-linear memristor device models for emerging neuromorphic computing hardware design

The value memristor devices offer to the neuromorphic computing hardware design community rests on the ability to provide effective device models that can enable large scale integrated computing architecture application simulations. Therefore, it is imperative to develop practical, functional device models of minimum mathematical complexity for fast, reliable, and accurate computing architecture technology design and simulation. To this end, various device models have been proposed in the literature seeking to characterize the physical electronic and time domain behavioral properties of memristor devices. In this work, we analyze some promising and practical non-quasi-static linear and non-linear memristor device models for neuromorphic circuit design and computing architecture simulation.
Adaptive signal processing for adaptive control

A few of the well established methods of adaptive signal processing are modified and extended for application to adaptive control. An unknown plant will track an input command signal if the plant is preceded by a controller whose transfer function approximates the inverse of the plant transfer function. An adaptive inverse modeling process can be used to obtain a stable controller, whether the plant is minimum or non-minimum phase. No direct feedback is involved. However the system output is monitored and utilized in order to adjust the parameters of the controller. The proposed method is a promising new approach to the design of adaptive control systems.
Palladium-catalyzed couplings to nucleophilic heteroarenes: the total synthesis of (−)-frondosin B

Abstract The total synthesis of (−)-frondosin B, the enantiomer of naturally-occuring (+)-frondosin B, is described, wherein a palladium-catalyzed cyclization is used to establish the tetracyclic ring system of the natural product.
The design and implementation of a self-calibrating distributed acoustic sensing platform

We present the design, implementation, and evaluation of the Acoustic Embedded Networked Sensing Box (ENSBox), a platform for prototyping rapid-deployable distributed acoustic sensing systems, particularly distributed source localization. Each ENSBox integrates an ARM processor running Linux and supports key facilities required for source localization: a sensor array, wireless network services, time synchronization, and precise self-calibration of array position and orientation. The ENSBox's integrated, high precision self-calibration facility sets it apart from other platforms. This self-calibration is precise enough to support acoustic source localization applications in complex, realistic environments: e.g., 5 cm average 2D position error and 1.5 degree average orientation error over a partially obstructed 80x50 m outdoor area. Further, our integration of array orientation into the position estimation algorithm is a novel extension of traditional multilateration techniques. We present the result of several different test deployments, measuring the performance of the system in urban settings, as well as forested, hilly environments with obstructing foliage and 20-30 m distances between neighboring nodes.
A set-theoretic approach to organizational configurations

I argue that research on organizational configurations has been limited by a mismatch between theory and methods and introduce set-theoretic methods as a viable alternative for overcoming this mismatch. I demonstrate the value of such methods for studying organizational configurations and discuss their applicability for examining equifinality and limited diversity among configurations, as well as their relevance to other research fields such as complementarities theory, complexity theory, and the resource-based view
The spirit of capitalism and long-run growth

Abstract In this paper, we will show that the capitalist-spirit approach to economic growth has been developed by Adam Smith, Karl Marx, Max Weber and John Maynard Keynes and many others. It can be demonstrated that countries with different degree of the capitalist spirit will have different per capita consumption, per capita capital stock and different endogenous growth rates in the long run. This capitalist spirit model is also widely supported by many empirical and historical studies on cultural attributes and economic development.
Active radio frequency pulse compression using switched resonant delay lines

Abstract This paper presents a study and design methodology for enhancing the efficiency of the SLED II rf pulse-compression system [P.B. Wilson, Z.D. Farkas and R.D. Ruth, Linear Accel. Conf., Albuquerque, NM, 1990]. This system employs resonant delay lines as a means of storing rf energy. By making the external quality factor of these lines vary as a function of time, the intrinsic efficiency of the system can reach 100%. However, we demonstrate a considerable increase in efficiency even if the change of the quality factor is limited to a single event in time. During this event, the quality factor of the lines changes from one value to another. The difference between these two values is minimized to simplify the realization of the quality factor switch. We present the system optimum parameters for this case. We also show the extension of this system to two events in time, during which the quality factor of the line changes between three predetermined states. The effects of the losses due to the delay lines and the switch used to change the quality factor are also studied.
Propagation of Fluctuations in Biochemical Systems, II: Nonlinear Chains

We consider biochemical reaction chains and investigate how random external fluctuations, as characterised by variance and coefficient of variation, propagate down the chains. We perform such a study under the assumption that the number of molecules is high enough so that the behaviour of the concentrations of the system is well approximated by differential equations. We conclude that the variances and coefficients of variation of the fluxes will decrease as one moves down the chain and, through an example, show that there is no corresponding result for the variances of the concentrations of the chemical species. We also prove that the fluctuations of the fluxes as characterised by their time averages decrease down reaction chains. The results presented give insight into how biochemical reaction systems are buffered against external perturbations solely by their underlying graphical structure and point out the benefits of studying the out-of-equilibrium dynamics of systems.
Mechanical Drawing of Gas Sensors on Paper

This communication describes a simple solvent-free method for fabricating chemoresistive gas sensors on the surface of paper. The method involves mechanical abrasion of compressed powders of sensing materials on the fibers of cellulose. We illustrate this approach by depositing conductive layers of several forms of carbon (e.g., single-walled carbon nanotubes [SWCNTs], multi-walled carbon nanotubes, and graphite) on the surface of different papers (Figure 1, Figure S1). The resulting sensors based on SWCNTs are capable of detecting NH3 gas at concentrations as low as 0.5 part-per-million.
Shaping current waveforms for direct modulation of semiconductor lasers

We demonstrate a technique for shaping current inputs for the direct modulation of a semiconductor laser for digital communication. The introduction of shaped current inputs allows for the suppression of relaxation oscillations and the avoidance of dynamical memory in the physical laser device, i.e., the output will not be influenced by previously communicated information. For the example of time-optimized bits, the possible performance enhancement for high data rate communications is shown numerically.
Modeling Land Use Decisions with Aggregate Data

In this article, we develop land use models to study the impact of changes in decision variables on soil erosion or other environmental outcomes. From an underlying behavioral model, we use maximum entropy to recover a parametric model of county-level land use shares as a function of decision variables such as output prices, input costs, and land quality. The statistical model may be extended to estimate subcounty land use shares and to incorporate data from federal land use surveys. We use the procedure to analyze the impact of changes in livestock inventories on soil erosion rates in three Iowa counties.
Measures and Their Random Reals

We study the randomness properties of reals with respect to arbitrary probability measures on Cantor space. We show that every non-computable real is non-trivially random with respect to some measure. The probability measures constructed in the proof may have atoms. If one rules out the existence of atoms, i.e. considers only continuous measures, it turns out that every non-hyperarithmetical real is random for a continuous measure. On the other hand, examples of reals not random for any continuous measure can be found throughout the hyperarithmetical Turing degrees.
Measurements and Model Validation for Composite Propellants Burning under Cross Flow of Gases

Erosive burning rates of three types of ammonium perchlorate-based composite propellant formulations were measured by using the high-speed motion picture method. Experiments were conducted in a test rig designed to develop a well-defined, turbulent boundary layer with a distinct leading edge by the flow of combustion gases over two-dimensional propellant samples. Erosive burning rate correlations which relate the burning rate to freestream velocity and pressure were developed. The comparison of experimental data and theoretical results obtained from the erosive burning model, based upon the turblilent boundary-layer approach developed by the authors, showed a close agreement.
The National Security Agency (NSA) eavesdropping on Americans A programme that is neither legal nor necessary

On 16 December 2005, the New York Times reported that the President had authorized the National Security Agency (NSA) to spy on Americans, inside the United States, without first obtaining a warrant from the secret FISA court. Although the President has described the NSA activities to be legal and critical to our national security, the programme has started a national controversy, raising questions over its legality and necessity. Consequently, there have been pending legal challenges, congressional investigations, and public outcry over the use of such expansive presidential authority. The legal community, including the American Bar Association, considers the programme illegal. The only district court that has addressed the issue has held it to be an unconstitutional programme that violates FISA. This comment highlights several reasons for why warrantless wiretapping is illegal and unnecessary. The comment also notes public policy reasons against presidential power that is not subject to any checks from Congress or review from the judiciary. Finally, it argues that the President needs to immediately cease the programme; asks Congress to take its oversight responsibility more seriously; and reasons that the judicial review protects against abuse.
Geometrically Thin Disk Accreting into a Black Hole

A numerical model of a steady state, thin accretion disk with a constant effective speed of sound is presented. We demonstrate that a "no torque" inner boundary condition is a reasonable approximation provided that the disk thickness, including the thickness of the torquing magnetic fields, is small everywhere. It is likely that this conclusion is correct also for nonsteady disks, as long as the total thickness at the sonic point, Hc, is much smaller than the radius there, rc ≈ rms. The very existence of thin disks is not proved or disproved in this work, but such disks are believed to exist for moderate accretion rates. Within our model there is a small torque at rms, which may increase disk luminosity by several percent. An important result of our analysis is that the physically acceptable steady state solutions in our toy model exist only for α < 0.14(100vs/c)1/3. A significant torque may be applied to a thin disk if there is a large-scale magnetic field, like in a modified Blandford-Znajek mechanism.
Direct reconstruction of kinetic parameter images from dynamic PET data

Our goal in this paper is the estimation of kinetic model parameters for each voxel corresponding to a dense three-dimensional (3-D) positron emission tomography (PET) image. Typically, the activity images are first reconstructed from PET sinogram frames at each measurement time, and then the kinetic parameters are estimated by fitting a model to the reconstructed time-activity response of each voxel. However, this "indirect" approach to kinetic parameter estimation tends to reduce signal-to-noise ratio (SNR) because of the requirement that the sinogram data be divided into individual time frames. In 1985, Carson and Lange proposed, but did not implement, a method based on the expectation-maximization (EM) algorithm for direct parametric reconstruction. The approach is "direct" because it estimates the optimal kinetic parameters directly from the sinogram data, without an intermediate reconstruction step. However, direct voxel-wise parametric reconstruction remained a challenge due to the unsolved complexities of inversion and spatial regularization. In this paper, we demonstrate and evaluate a new and efficient method for direct voxel-wise reconstruction of kinetic parameter images using all frames of the PET data. The direct parametric image reconstruction is formulated in a Bayesian framework, and uses the parametric iterative coordinate descent (PICD) algorithm to solve the resulting optimization problem. The PICD algorithm is computationally efficient and is implemented with spatial regularization in the domain of the physiologically relevant parameters. Our experimental simulations of a rat head imaged in a working small animal scanner indicate that direct parametric reconstruction can substantially reduce root-mean-squared error (RMSE) in the estimation of kinetic parameters, as compared to indirect methods, without appreciably increasing computation.
Interactions, neighborhood selection and housing demand

Abstract This paper contributes to the growing literature that aims at identifying and measuring the impact of social context on individual economic behavior. We develop a model of housing structure demand with neighborhood effects and neighborhood choice. Modeling neighborhood choice is of fundamental importance in estimating and understanding endogenous and contextual neighborhood effects. Controlling for non-random sorting into neighborhoods allows for unbiased estimates and provides a means for identifying endogenous neighborhood effects. Estimation of the model exploits a household-level data set that has been augmented with contextual information at two different levels (“scales”) of aggregation. One is at the neighborhood level, consisting of about ten neighbors, with the data coming from the neighborhood clusters sub-sample of the American Housing Survey. A second level is the census tract to which these dwelling units belong. These data were geocoded by means of privileged access to confidential US Census data. Our results for the neighborhood choice model indicate that individuals prefer to live near others like themselves. Our estimates of the housing structure demand equation confirm that neighborhood effects are important. In particular, one's demand for housing depends on the mean of neighbors' demand for housing.