cssi/SciSciGPT-SciSciNet huggingface dataset:
A facile transfer fluorination approach to the synthesis of N-fluoro sulfonamides

Abstract The synthesis of N -fluoro sulfonamides can be readily accomplished by the transfer fluorination of the potassium salt of the sulfonamide with the readily available, solid fluorinating agent, N -fluoro benzenesulfonimide. The fluorination requires no special equipment or techniques, and is both rapid and general.
Aversive factors in alcohol drinking in humans and animals.

In human subjects there is a wide range of response to the taste of alcohol in varying concentrations. What some people find totally aversive may be accepted with relish by others. Both individual and racial responses to ingested or injected alcohol can be aversive, since markedly dysphoric experiences can occur. Human studies also suggest that the euphorigenic properties of alcohol are very variable between subjects and that this correlates with characteristics of biogenic amines present in the body. Except for relatively low concentrations, the laboratory rat, used commonly in alcohol drinking experiments, avoids the selection of alcohol. Paralleling human studies are animal investigations that manipulate the levels of chemical substances in the brain and demonstrate effects of this upon alcohol self-selection. When certain tetrahydroisoquinolines or β -carboline substances are infused into the brain of the rat or monkey, the aversive nature of orally ingested alcohol, particularly in very high concentrations, is overcome. In contrast, however, when a high dose of a tetrahydropapaveroline is infused, the animal's volitional intake of alcohol is inhibited and even weak concentrations of alcohol are rejected. The possible mechanisms for this phenomenon and the recent investigations of agents acting on CNS opiate receptors in reinstating alcohol aversion are considered.
Electrophoresis of a polyelectrolyte through a nanopore

A hydrodynamic model for determining the electrophoretic speed of a polyelectrolyte through a nanopore is presented. It is assumed that the speed is determined by a balance of electrical and viscous forces arising from within the pore and that classical continuum electrostatics and hydrodynamics may be considered applicable. An explicit formula for the translocation speed as a function of the pore geometry and other physical parameters is obtained and is shown to be consistent with experimental measurements on DNA translocation through nanopores in silicon membranes. Experiments also show a weak dependence of the translocation speed on polymer length that is not accounted for by the present model. It is hypothesized that this is due to secondary effects that are neglected here.
Auctions With A Minimum Requirement Of Bids

We show that in a procurement auction with independent and private costs of production and a positive cost of preparing a bid, the requirement of a minimum number of offers for the good to be bought always yields a unique (perfect) Bayesian equilibrium where no firm enters a bid, whatever its cost of production, the number of potential bidders and the size of the bidding cost. To avoid the no-bid result, the buyer can commit to subsidise the losing bidders in certain circumstances. Alternatively, it can use a stochastic auction, where the provider of the good is not always the firm that bids the lowest price.
Mutasynthesis of Fluorinated Pactamycin Analogues and Their Antimalarial Activity

A mutasynthetic strategy has been used to generate fluorinated TM-025 and TM-026, two biosynthetically engineered pactamycin analogues produced by Streptomyces pactum ATCC 27456. The fluorinated compounds maintain excellent activity and selectivity toward chloroquine-sensitive and multidrug-resistant strains of malarial parasites as the parent compounds. The results also provide insights into the biosynthesis of 3-aminobenzoic acid in S. pactum.
Elastic interaction of two atoms adsorbed on a solid surface

The long-range interaction of two adsorbed atoms mediated by the elastic distortion of the substrate is calculated classically for an elastically isotropic substrate. For identical atoms, the interaction is repulsive; for different atoms, it can be repulsive or attractive. It varies as ρ−3 with the distance ρ between the two adsorbed atoms. This is the same spatial dependence as for the dipole - dipole interaction between two adsorbed atoms. For two xenon atoms adsorbed on gold, the elastic interaction is somewhat smaller than the dipole-dipole interaction. The interaction energy is inversely proportional to the shear modulus of the substrate, so that it may become quite large near a distortive phase transition.
ATMOSPHERIC PARAMETERS OF FIELD L AND T DWARFS

We present an analysis of the 0.95-14.5 ?m spectral energy distributions of nine field ultracool dwarfs with spectral types ranging from L1 to T4.5. Effective temperatures, gravities, and condensate cloud sedimentation efficiencies are derived by comparing the data to synthetic spectra computed from atmospheric models that self-consistently include the formation of condensate clouds. Overall, the model spectra fit the data well, although the agreement at some wavelengths remains poor due to remaining inadequacies in the models. Derived effective temperatures decrease steadily through the L1-T4.5 spectral types, and we confirm that the effective temperatures of ultracool dwarfs at the L/T transition are nearly constant, decreasing by only ~200 K from spectral types L7.5 to T4.5. The condensate cloud properties vary significantly among the L dwarfs in our sample, ranging from very thick clouds to relatively thin clouds with no particular trend with spectral type. The two objects in our sample with very red -->J ? Ks colors are, however, best fitted with synthetic spectra that have thick clouds, which hints at a possible correlation between the near-infrared colors of L dwarfs and the condensate cloud properties. The fits to the two T dwarfs in our sample (T2 and T4.5) also suggest that the clouds become thinner in this spectral class, in agreement with previous studies. Restricting the fits to narrower wavelength ranges (i.e., individual photometric bands) almost always yields excellent agreement between the data and models. Limitations in our knowledge of the opacities of key absorbers such as FeH, VO, and CH4 at certain wavelengths remain obvious, however. The effective temperatures obtained by fitting the narrower wavelength ranges can show a large scatter compared to the values derived by fitting the full spectral energy distributions; deviations are typically ~200 K and, in the worst cases, up to 700 K.
The Optimality of a Simple Market Mechanism

Strategic behavior in a finite market can cause inefficiency in the allocation, and market mechanisms differ in how successfully they limit this inefficiency. A method for ranking algorithms in computer science is adapted here to rank market mechanisms according to how quickly inefficiency diminishes as the size of the market increases. It is shown that trade at a single market-clearing price in the k-double auction is worst-case asymptotic optimal among all plausible mechanisms: evaluating mechanisms in their least favorable trading environments for each possible size of the market, the k-double auction is shown to force the worst-case inefficiency to zero at the fastest possible rate.
An on-line machine language debugger for OS/360

The environment provided by the multiprogrammed options of Operating System 360 is not the most suitable for debugging. It is primarily a batch system, with a programmer's card deck disappearing into the card reader and reappearing at some future time on a printer. What happens in between is often impossible to discern; any attempt to monitor a program's execution (e.g., the setting of an address stop) is so complicated that it is nearly impossible. In this environment, debugging is difficult---at the conclusion of a program, the programmer either has successful execution or some indication of program error. If he planned ahead (and was lucky), his output will include not only an indication of the actual error, if one occurred, but trace information (either through OS TESTRAN facilities or his own printouts) to help him determine the problem. However, he is usually presented with a dump, containing a numerical reference to the completion-codes manual. More importantly, the dump represents the state of the system when OS decided it could not continue the program's execution; the user must discover why it went wrong by educated guesses and by "playing computer" with his program. The difficulty and sheer wastefulness of this procedure is extremely evident. For this purpose, an on-line symbolic debugger can be invaluable.
Active tape steering control system

Lateral tape motion (LTM) in tape drives hinders accurate servo head positioning and can cause damage to the tape. It is one of the major obstacles to developing high density, high performance tape drives. This paper presents the development an active tape steering system to reduce LTM. The paper also shows the use of Robust Bode (RBode) plot, a relatively new technique for designing robust controllers. The RBode plot translates a robust performance criterion into allowable and forbidden regions on the open-loop Bode plot of a compensated SISO system. With the RBode plot robust controllers can be directly synthesized with classical loop shaping.
Phase Separation in Symmetric Mixtures of Oppositely Charged Rodlike Polyelectrolytes

Phase separation in salt-free symmetric mixtures of oppositely charged rodlike polyelectrolytes is studied using quasi-analytical calculations. Stability analyses for the isotropic−isotropic and the isotropic−nematic phase transitions in the mixtures are carried out and demonstrate that electrostatic interactions favor nematic ordering. Coexistence curves for the symmetric mixtures are also constructed and are used to examine the effects of linear charge density and electrostatic interaction strength on rodlike polyelectrolyte complexation. It is found that the counterions are uniformly distributed in the coexisting phases for low electrostatic interaction strengths dictated by the linear charge density of the polyelectrolytes and Bjerrum’s length. However, the counterions also partition along with the rodlike polyelectrolytes with an increase in the electrostatic interaction strength. It is shown that the number density of the counterions is higher in the concentrated (or “coacervate”) phase than in the ...
A Preparative Scale Reduction of Alkyl Disulfides with Tributyl Phosphine and Water

Abstract A series of alkyl disulfides has been shown to be reduced by tributyl phosphine at room temperature. The resulting thiols were then acylated in the same pot and isolated in good yields. This sequence is convenient and is a practical option for the preparation of gram quantities of thiol or thioester from the corresponding disulfide.
Transit Draft Heave and Pitch Motion Analysis of the Mobile Offshore Base (MOB) Using Reverse MI/SO Techniques

A major design feature of the Mobile Offshore Base (MOB) is its ability to transit anywhere in the world in the required time frame. This means that the MOB must be able to transit in severe environmental conditions. In these extreme sea conditions, a primary cause for concern is the large accelerations that the vessel motions might experience due to the high static stability of the MOB at Transit Draft. Furthermore, since the vessel has minimum freeboard in this condition, it is exposed to green water over the pontoon tops. The submergence of the pontoon deck causes a considerable loss in the vessel’s restoring moment. These concerns have warranted a study by the Office of Naval Research into the Transit Draft Dynamics of the MOB. A part of the research in progress involves the development of a non-linear system modeling and optimization tool utilizing Reverse MI/SO (Multiple-Input/Single Output) techniques. Reverse MI/SO is based on the statistical signal processing of the recorded time histories of the excitation and response of the non-linear multi-degree-of-freedom system. This method of analysis is functional and reliable in identifying an ideal representation of the linear and non-linear terms of the system under consideration. Reverse MI/SO is a frequency domain analysis technique that also provides coherence functions for each of the terms in the model enabling an evaluation of the correctness of the proposed integro-diffrential equation of motion representing the system.Copyright © 2002 by ASME
Leveraging Social Networks to Combat Collusion in Reputation Systems for Peer-to-Peer Networks

In peer-to-peer networks (P2Ps), many autonomous peers without preexisting trust relationships share resources with each other. Due to their open environment, the P2Ps usually employ reputation systems to provide guidance in selecting trustworthy resource providers for high reliability and security; however, node collusion impairs the effectiveness of reputation systems in trustworthy node selection. Although some reputation systems have certain mechanisms to counter collusion, the effectiveness of the mechanisms is not sufficiently high. In this paper, we leverage social networks to enhance the capability of reputation systems in combating collusion. We first analyzed real trace of the reputation system in the Overstock online auction platform, which incorporates a social network. The analysis reveals the impact of the social network on user purchasing and reputation rating patterns. We, thus, identified suspicious collusion behavior patterns and propose a social network-based mechanism, SocialTrust, to counter collusion. SocialTrust adaptively adjusts the weight of ratings based on the social distance and interest relationship between peers. Experiment results show that SocialTrust can significantly strengthen the capability of current reputation systems in combating collusion.
Synthesis of enantiomers of 2′-aminomethyl-5-benzylacyclouridine (AM-BAU) and 2′-aminomethyl-5-benzyloxybenzylacyclouridine (AM-BBAU). Potent inhibitors of uridine phosphorylase

Racemic 2′-aminomethyl-5-benzyl-acyclouridine (AM-BAU, 5) and 2′-aminomethyl-5-benzyloxybenzyla-cyclouridine (AM-BBAU, 6) have been found to be very active inhibitors of uridine phosphorylase [1]. Their enantiomers were synthesized from chiral 2,2-dimethyl-1,3-dioxolane-4-methanol (7a,b). S-(—)-AM-BAU (5a) and S-(—)-AM-BBAU (6a) were prepared from the R-(—) isomer 7a, and R(+)-AM-BAU (5b) and R-(+)-AM-BBAU (6b) from the S-(+) isomer 7b. A different route from the S-(+) isomer 7b to S-(—)-AM-BBAU (6a) was also determined to be feasible.
Properties of the soliton-lattice state in double-layer quantum Hall systems

Abstract Application of a sufficiently strong parallel magnetic field B∥>Bc produces a soliton-lattice (SL) ground state in a double-layer quantum Hall system. We calculate the ground-state properties of the SL state as a function of B∥ for total filling factor νT=1, and obtain the total energy, anisotropic SL stiffness, Kosterlitz–Thouless melting temperature, and SL magnetization. The SL magnetization might be experimentally measurable, and the magnetic susceptibility diverges as |B∥−Bc|−1.
Critical Points of Holomorphic Sections of Line Bundles and a Spherical Gauss–Lucas Theorem

We study critical points of holomorphic sections of \(\mathcal {O}(m)\) on \({\mathbb{C}}{\mathbb{P}}^{n}\). For quadrics, we give a complete description of their critical points. When n=1, we prove a spherical Gauss–Lucas theorem. For the general situation, we prove that a generic section has all its critical points isolated and non-degenerate.
Best Algorithms for Approximating the Maximum of a Submodular Set Function

A real-valued function z whose domain is all of the subsets of N = {1,..., n is said to be submodular if zS + zT ≥ zS ∪ T + zS ∩ T, ∀S, T ⊆ N, and nondecreasing if zS ≤ zT, ∀S ⊂ T ⊆ N. We consider the problem maxS⊂N {zS: |S| ≤ K, z submodular and nondecreasing, zO = 0}. Many combinatorial optimization problems can be posed in this framework. For example, a well-known location problem and the maximization of certain boolean polynomials are in this class. We present a family of algorithms that involve the partial enumeration of all sets of cardinality q and then a greedy selection of the remaining elements, q = 0,..., K-1. For fixed K, the qth member of this family requires Onq+1 computations and is guaranteed to achieve at least $$\biggl[1-\biggl\frac{K-q}{K}\biggr\biggl\frac{K-q-1}{K-q}\biggr^{K-q}\biggr]\times100 \quad\mbox {percent of the optimum value}.$$ Our main result is that this is the best performance guarantee that can be obtained by any algorithm whose number of computations does not exceed Onq+1.
THE ROLE OF RIFTING IN THE TECTONIC DEVELOPMENT OF THE MIDCONTINENT, U.S.A.

Abstract Recent studies have proposed the existence of several major ancient rift zones in the midcontinent region of North America. Although the dating of some of these rifts (and even the rift interpretations) are subject to question, an analysis of these “paleo-rifts” reveals three major episodes of rifting: Keweenawan (~ 1.1 b.y. B.P.), Eocambrian (~ 600 m.y. B.P.), and early Mesozoic (~ 200 m.y. B.P.). The extent of these events documents that rifting has played a major role in the tectonic development of the midcontinent region. This role goes well beyond the initial rifting event because these features display a strong correlation with Paleozoic basins and a strong propensity for reactivation. For example, the Eocambrian Reelfoot rift was reactivated in the Mesozoic to form the Mississippi embayment and is the site of modern seismicity which suggests reactivation in a contemporary stress field of ENE compression. Even though the importance of rifting can be established, recognition of rifts and delineation of their complexities remain a major problem which requires more study.
Third-harmonic generation in cuprous oxide: Efficiency determination

The efficiency of third-harmonic generation in cuprous oxide was measured. Intensities followed a noncubic power law that indicates nonperturbative behavior. Polarization anisotropy of the harmonic generation was demonstrated and related to the third-order susceptibility. The results will influence the understanding of harmonic generation in centrosymmetric materials and are potentially relevant to device design and the interpretation of exciton behavior.
't Hooft vortices on D-branes

The point where a D2-brane intersecting a stack of D2-branes is proposed as a candidate for the 't Hooft vortex in the world-volume theory of N D2-branes. This straightforwardly generalizes to D3-branes, where a vortex line is generated by the intersection. Similarly, there are such objects on M-branes. We use Maldacena's conjecture to compute the static potential between a vortex and an anti-vortex in each case, in the large N limit.
p-Version two-dimensional beam element for geometrically nonlinear analysis

Abstract This paper presents a p -version geometrically nonlinear formulation (GNL) based on the total Lagrangian approach for a three-node two-dimensional curved beam element. The hierarchical element approximation functions and the corresponding nodal variables are derived directly from the Lagrange family of interpolation functions. The resulting element displacement approximation is hierarchical and can be of arbitrary and different polynomial orders in the longitudinal and the transverse directions of the beam element and ensures C 0 continuity. The element geometry is described by the coordinates of the nodes located on the axis of the beam (middle surface) and the nodal vectors describing the top and bottom surfaces of the element. The element properties are established using the principle of virtual work and the hierarchical element displacement approximation. In formulating the properties of the element complete two-dimensional stresses and strains are considered hence the element is equally effective for very slender as well as extremely deep beams. Incremental equations of equilibrium are derived and solved using the standard Newton-Raphson method. The total load is divided into increments, and for each increment of load, equilibrium iterations are performed until each component of the residuals is within a preset tolerance. Numerical examples are presented to show the accuracy, efficiency and advantages of the present formulation. The results obtained from the present formulation are compared with those reported in the literature. The formulation presented here removes virtually all of the drawbacks present in existing GNL beam finite element formulations and has many additional benefits. First, the currently available GNL beam formulations are based on fixed order of approximation for the displacements and thus are not hierarchical and have no provision for changing the order of approximation for the displacements u and v . Secondly, the element displacement approximations in the existing formulations are either based on a linearized displacement field for which a true Lagrangian formulation is not possible and the incremental load step size is severely limited or are based on nonlinear nodal rotation function approach in which case even though the description of the displacement field for the element is exact but additional complications arise due to the noncummutative nature of the nonlinear nodal rotation functions. The p -version displacement approximation used here does not involve the traditional nodal rotations that have been used in the existing beam formulations, thus the difficulties associated with their use are not present in this formulation.
Hybridization, hole localization and pair breaking in the high Tc superconducting system Y1-xPrxBa2Cu3O7-δ

Abstract The Y 1- x Pr x Ba 2 Cu 3 O 7- δ ( δ ≈ 0.05) system has a rich temperature—praseodymium concentration ( T - x ) phase diagram consisting of a metal—insulator transition at x cr ≈0.6, high T c superconductivity in the metallic phase (0⩽ x ≤ x cr ), and antiferromagnetic ordering of the Cu 2+ and praseodymium ions at Neel temperatures T N (Cu) > T N (Cu)> T N (Pr) in the insulating phase ( x cr ≤ x ⩽1). In the metallic phase, T c decreases monotonically with x and vanishes near x cr , the dependence of T c on pressure P and the upper critical field on temperature are both anomalous, and the low temperature specific heat can be resolved into a large γΓ contribution, reminiscent of heavy fermion behavior, and a spin 1 2 Kondo anomaly; in the insulating phase, the values of T N (Pr) are anomalously large. These phenomena are briefly reviewed within the framework of a picture that is based on appreciable hybridization of the praseodymium localized 4f states and the CuO 2 valence band states. A phenomenological model that incorporates the annihilation of mobile holes in the CuO 2 planes and superconducting electron pair breaking by the praseodymium ions can describe T c ( x , P ) for x ≤ 0.2.
Radio Properties of Low-Redshift Broad Line Active Galactic Nuclei

The question as to whether the distribution of radio loudness in active galactic nuclei (AGNs) is actually bimodal has been discussed extensively in the literature. Furthermore, there have been claims that radio loudness depends on black hole mass (M BH) and Eddington ratio (L bol/L Edd). We investigate these claims using the low-redshift broad line AGN sample of Greene & Ho, which consists of 8434 objects at z 10) and radio quiet ( 108 M ☉. We find for the FIRST detected subsample that 367 of the RL AGNs have M BH < 108 M ☉, a large enough number to indicate that RL AGNs are not a product of only the most massive black holes in the local universe.
Measuring the supersymmetry lagrangian

Abstract The parameters of the supersymmetry Lagrangian are the place where experiment and theory will meet. We show that measuring them is harder than has been thought, particularly because of large unavoidable dependences on phases. Measurements are only guaranteed if a lepton collider with a polarized beam and sufficient energy to produce the relevant sparticles is available. Current limits on superpartner masses, WIMPs, and the supersymmetric Higgs are not general, and need re-evaluation. We also tentatively define the MRM (Minimum Reasonable Model), whose parameters may be measurable at LEP, FNAL and LHC.
Do lower income areas have more pedestrian casualties

Pedestrian and motor vehicle casualties are analyzed for the State of New Jersey with the objective of determining how the income of an area may be associated with casualties. We develop a maximum-likelihood negative binomial model to examine how various spatially defined variables, including road, income, and vehicle ownership, may be associated with casualties using census block-group level data. Due to suspected spatial correlation in the data we also employ a conditional autoregressive Bayesian model using Markov Chain Monte Carlo simulation, implemented with Crimestat software. Results suggest that spatial correlation is an issue as some variables are not statistically significant in the spatial model. We find that both pedestrian and motor vehicle casualties are greater in lower income block groups. Both are also associated with less household vehicle ownership, which is not surprising for pedestrian casualties, but is a surprising result for motor vehicle casualties. Controls for various road categories provide expected relationships. Individual level data is further examined to determine relationships between the location of a crash victim and their residence zip code, and this largely confirms a residual effect associated with both lower income individuals and lower income areas.
A theoretical analysis of the role of social networks in entrepreneurship

Entrepreneurship involves innovation and uncertainty. We outline a theory of entrepreneurship, which highlights the importance of social networks in promoting innovation and reducing uncertainty. Our findings suggest that this “social” aspect of entrepreneurship increases the probability of entrepreneurial success. The results also lend credence to theories of entrepreneurship that suggest that entrepreneurial opportunities are formed endogenously by the entrepreneurs who create them. We also consider the public policy implications of our findings.
Testing urine for drugs.

The analysis of body fluids for drugs takes place in two distinctly different environments: the medical model and the penalty model. In the former, and in the context of patient care, the physician requests the test and the patient is both fully co-operative with the sample collectors and highly motivated to provide the ideal sample. In the latter case, the request usually comes from a non-medical authority and it may not be in the best interest ofthe individual to submit a valid sample. In the medical model the information obtained from the test is used to assist the physician in the care and management of the patient. In contrast, in the penalty model the results are used to impose some penalty to the individual. This fundamental difference, together with legal imperatives, has broad implications for the overall design and implementation of a drug testing programme.
Managing Outsourced Software Projects: An Analysis of Project Performance and Customer Satisfaction

We examine the drivers of project performance and customer satisfaction in outsourced software projects using a proprietary panel dataset. The data cover 822 customer observations related to 182 unique projects executed by an India-based software services vendor. Adopting a multidisciplinary perspective, we investigate how project planning, team stability, and communication effectiveness impact project performance and customer satisfaction. We delineate the direct and interactive influences of the antecedent variables. We also examine how these influences are moderated by two important project contexts: (a) the nature of software work (maintenance and development vs. testing projects) and (b) project maturity (new vs. mature projects). Among other results, we demonstrate that, when project planning capabilities are high, the positive impact of team stability and communication effectiveness on project performance is even higher. In addition, our results suggest that the impact of communication on project performance is muted when team stability is high. Finally, we also demonstrate that the impact of the antecedent variables on project performance varies with the nature of software work. Our findings offer specific and actionable insights to managers that can help them manage outsourced projects better, and open up new research perspectives in the context of outsourced project management.
Attenuating illusory binding with TMS of the right parietal cortex

A number of neuroimaging and neuropsychology studies have implicated various regions of parietal cortex as playing a critical role in the binding of color and form into conjunctions. The current study investigates the role of two such regions by examining how parietal transcranial magnetic stimulation (TMS) influences binding errors known as ‘illusory conjunctions.’ Participants made fewer binding errors after 1 Hz rTMS of the right intraparietal sulcus (IPS), while basic perception of features (colors and shape) was unaffected. No perceptual effects were found following left IPS stimulation, or stimulation of the right angular gyrus at the junction of the transverse occipital sulcus (IPS/TOS). These results support a role for the parietal cortex in feature binding but in ways that may require rethinking.
Centrifugal Casting of Microfluidic Components With PDMS

This work describes the centrifugal casting and fast curing of double-sided, polydimethylsiloxane (PDMS)-based components with microfeatures. Centrifugal casting permits simultaneous patterning of multiple sides of a component and allows control of the thickness of the part in an enclosed mold without entrapment of bubbles. Spinning molds filled with PDMS at thousands of revolutions per minute for several minutes causes entrapped bubbles within the PDMS to migrate toward the axis of rotation or dissolve into solution. To cure the parts quickly (<10 min), active elements heat and cool cavities filled with PDMS after the completion of spinning. Microfluidic channels produced from the process have a low coefficient of variation (<2% for the height and width of channels measured in 20 parts). This process is also capable of molding functional channels in opposite sides of a part as demonstrated through a device with a system of valves typical to multilayer soft lithography.
Highly optimized fourth-order short-time approximation for path integrals.

We derive a fourth-order short-time approximation for use in imaginary-time path-integral simulations. The short-time approximation converges for all continuous and bounded from below potentials, attains quartic order of convergence for sufficiently smooth potentials, and utilizes statistically independent random variables for its construction. These properties recommend the approximation as a natural replacement of the trapezoidal Trotter-Suzuki approximation for physical systems with continuous distributions.
Total energy distributions of field-emitted electrons at high current density

Measurements of the total energy distributions (TED) have been carried out at high current densities ($J={10}^{6} \mathrm{to} {10}^{8}$ A/${\mathrm{cm}}^{2}$) for a high-work-function ($\ensuremath{\varphi}=4.5$ eV) and low-work-function ($\ensuremath{\varphi}=2.5$ eV) field emitter. At high values of $J$, both emitters give values of the full width at half maximum (FWHM) of the TED which exceed the values based on Fowler-Nordheim theory by a few eV. This deviation of the FWHM values increases with $J$, is independent of temperature, and decreases with emitter radius for a specified beam acceptance angle. The study of these anomalous values of FWHM values extends from 84 to 1975 K. It is believed that Coulomb interaction in the vacuum space in front of the emitter can account for these results, although internal electron energy-broadening mechanisms cannot be ruled out.
Deblending using a space-varying median filter

Deblending is a currently popular method for dealing with simultaneous-source seismic data. Removing blending noise while preserving as much useful signal as possible is the key to the deblending process. In this paper, I propose to use a space-varying median filter (SVMF) to remove blending noise. I demonstrate that this filtering method preserves more useful seismic reflection than does the conventional version of a median filter (MF). In SVMF, I use signal reliability (SR) as a reference to pick up the blending spikes and increase the window length in order to attenuate the spikes. When useful signals are identified, the window length is decreased in order to preserve more energy. The SR is defined as the local similarity between the data initially filtered using MF and the original noisy data. In this way, SVMF can be regionally adaptive, instead of rigidly using a constant window length through the whole profile for MF. Synthetic and field-data examples demonstrate excellent performance for my propos...
MEMS adaptive optics for the Gemini Planet Imager: control methods and validation

The Gemini Planet Imager (GPI) Adaptive Optics system will use a high-order MEMS deformable mirror for phase compensation. The MEMS mirror will be used in a Woofer-Tweeter configuration, with a frequency-domain based splitting of the phase between the two mirrors. Precise wavefront control depends on the ability to command them MEMS to make the exact phase desired. Non-linearities in the MEMS may prevent this. We determine that influence-function pre-compensation can remove most, but not all, open-loop error. We use simulation and a simulation of a non-linear MEMS to address the issue of how much non-linearity can be tolerated in closed-loop by GPI.
A comparison of weight histories in women with class III vs. class I–II obesity

Abstract Objective To describe the weight histories of women with extreme or class III obesity (BMI ≥ 40 kg/m 2 ) in comparison with a sample of women with class I-II obesity (BMI 2 ) and to provide reliability data for a clinical instrument that assesses weight history. Research methods and procedures Female patients ( N = 149) with extreme obesity seeking bariatric surgery and 90 class I–II obese women seeking behavioral treatment completed the Weight and Lifestyle Inventory (WALI), a self-report instrument that assesses age of onset of obesity, maximum weight at different ages, family weight history, and weight changes related to pregnancy. Test-retest reliability data were obtained by administering the WALI to a subsample ( n = 58) of class I–II obese participants at their initial visit and at another pretreatment visit 1 to 2 weeks later. Results Patients with extreme obesity had a significantly younger age of onset of obesity, were significantly heavier at all age ranges, reported significantly more weight gain with their first pregnancy, and had significantly heavier parents and siblings as compared with less obese patients. There were no significant differences between groups with respect to weight gain during second pregnancies or postpartum weight retention. Robust test-retest correlations were obtained for the weight history items on the WALI. Discussion Patients with extreme obesity report more indicators of a genetic predisposition to obesity as compared with less obese patients. The WALI appears to be a reliable instrument for the assessment of weight history in obese patients.
Double three-step phase-shifting algorithm.

We describe what we believe is a new phase-shifting algorithm called a double three-step algorithm developed to reduce the measurement error of a three-dimensional shape-measurement system, which is based on digital fringe-projection and phase-shifting techniques. After comparing the performance of different existing phase-shifting algorithms, we present the new double three-step algorithm based on the error analysis of the standard three-step algorithm. In this algorithm, three-step phase shifting is done twice with an initial phase offset of 60° between them, and the two obtained phase maps are averaged to generate the final phase map. Both theoretical and experimental results showed that this new algorithm worked well in significantly reducing the measurement error.
Converting metals into phosphides: a general strategy for the synthesis of metal phosphide nanocrystals.

Nanocrystals of metal phosphides, which can have useful catalytic, electronic, and magnetic properties, are known to be accessible by using trioctylphosphine (TOP) as a highly reactive phosphorus source. Here we report a general strategy for synthesizing transition metal phosphides, including those with 4d and 5d transition metals that have not previously been reported as unsupported nanocrystals. Unlike previously reported methods that involve direct decomposition of organometallic precursors, our method utilizes preformed metal nanoparticles as templates for generating metal phosphide nanocrystals. Metal nanoparticles are reacted with TOP in a hot solvent (290−360 °C) to form transition metal phosphides such as Ni2P, PtP2, Rh2P, PdP2, Pd5P2, and Au2P3. Furthermore, nanostructures such as hollow spheres can be easily made using a Kirkendall-type mechanism, which utilizes metal nanoparticles as reactive templates.
Random-field Ising model in and out of equilibrium

We present numerical studies of zero-temperature Gaussian random-field Ising model (zt-GRFIM) in both equilibrium and non-equilibrium. We compare the universal quantities in 3D (avalanche critical exponents and scaling functions, fractal dimensions, and anisotropy measures) for the equilibrium and non-equilibrium disorder-induced phase transitions. We show compelling evidence that the two transitions belong to the same universality class.
Anomalous Capacitive Sheath with Deep Radio Frequency Electric Field Penetration

A novel nonlinear effect of anomalously deep penetration of an external radio-frequency electric field into a plasma is described. A self-consistent kinetic treatment reveals a transition region between the sheath and the plasma. Because of the electron velocity modulation in the sheath, bunches in the energetic electron density are formed in the transition region adjusted to the sheath. The width of the region is of order V(subscript T)/omega, where V(subscript T) is the electron thermal velocity, and w is frequency of the electric field. The presence of the electric field in the transition region results in a cooling of the energetic electrons and an additional heating of the cold electrons in comparison with the case when the transition region is neglected.
A sharp stability result for the relative isoperimetric inequality inside convex cones

The relative isoperimetric inequality inside an open, convex cone \(\mathcal{C}\) states that, at fixed volume, \(B_{r} \cap\mathcal{C}\) minimizes the perimeter inside \(\mathcal{C}\). Starting from the observation that this result can be recovered as a corollary of the anisotropic isoperimetric inequality, we exploit a variant of Gromov’s proof of the classical isoperimetric inequality to prove a sharp stability result for the relative isoperimetric inequality inside \(\mathcal{C}\). Our proof follows the line of reasoning in Figalli et al.: Invent. Math. 182:167–211 (2010), though several new ideas are needed in order to deal with the lack of translation invariance in our problem.
Methane and climate during the Precambrian era

Abstract The Sun was substantially less bright in the distant past, yet Earth's surface temperature remained above freezing. Higher concentrations of the greenhouse gases CO 2 and CH 4 were likely responsible for keeping the early climate warm. CH 4 concentrations of 1000 ppm or higher are predicted for the Late Archean/Paleoproterozoic atmosphere prior to the rise of O 2 . Photolysis of this CH 4 may have created an optically thin organic haze during much of this time. The rise of O 2 at 2.3 Ga eliminated most of the methane and probably triggered the Paleoproterozoic glaciations. CH 4 concentrations could have remained elevated throughout much of the Proterozoic, however, as a consequence of low concentrations of dissolved O 2 and sulfate in the deep oceans and a corresponding increase in organic matter recycling by fermentation and methanogenesis.
Responses of photoreceptors

Publisher Summary This chapter describes the responses of photoreceptors. Visual pigments are contained in specialized nerve cells, the photoreceptors, that have the ability to transform light into an electrical signal. It is observed that light adaptation decreases sensitivity, while it increases temporal resolution. These phenomena are well known in psychophysics as it can be clearly demonstrated that in the presence of a background light or after a period of intense illumination, a flash becomes less visible but flicker fusion frequency is increased. These results suggest that the response to a flash becomes smaller and faster with light adaptation and, in fact, these changes can be observed directly by recording the responses of visual cells. It is seen in experiments of this type that the changes of sensitivity and of time course are correlated, but the decrease of sensitivity is much greater than the shortening of the time scale. In visual cells of Limulus, a, decrease of sensitivity by a factor of 500 is associated with an acceleration of the time course by a factor of about 2. The multistage model is quite suitable for reproducing this relation as sensitivity and time course of responses are controlled by the value of the parameter representing the rate of decay of the intermediary processes.
Algebraic hypergeometric transformations of modular origin

It is shown that Ramanujan's cubic transformation of the Gauss hypergeometric function 2 F 1 arises from a relation between modular curves, namely the covering of X 0 (3) by X 0 (9). In general, when 2≤ N≤ 7, the N-fold cover of X 0 (N) by X 0 (N 2 ) gives rise to an algebraic hypergeometric transformation. The N = 2,3,4 transformations are arithmetic-geometric mean iterations, but the N = 5,6,7 transformations are new. In the final two cases the change of variables is not parametrized by rational functions, since X 0 (6),X 0 (7) are of genus 1. Since their quotients X 0 + (6),X 0 + (7) under the Fricke involution (an Atkin-Lehner involution) are of genus 0, the parametrization is by two-valued algebraic functions. The resulting hypergeometric transformations are closely related to the two-valued modular equations of Fricke and H. Cohn.
Bridge structure for the graphene/Ni(111) system : A first principles study

The structure of graphene on Ni(111) is studied with density functional theory (DFT). Six different structures, i.e., top-fcc, top-hcp, hcp-fcc, bridge-top, bridge-fcc, and bridge-hcp, were investigated. Bridge-top, bridge-fcc, and bridge-hcp are studied here. Top-fcc and hcp-fcc have been considered before, experimentally and theoretically, and regarded as energetically stable structures. The calculations employed the local density approximation (LDA) and the Perdew, Burke, and Ernzerhof (PBE) generalized-gradient approximation to DFT. The results showed that with PBE, none of the structures is stable at the experimentally relevant temperatures; with LDA, only bridge-top and top-fcc are stable. These findings suggest that it will be worthwhile to carry on new experimental studies to revisit the structural determination of the graphene/Ni(111) system, with special emphasis on testing whether bridge-top could exist by itself or coexist with other structures.
Modeling the dynamics of inhomogeneous natural rotifer populations under toxicant exposure

Most population models assume that individuals within a given population are identical, that is, the fundamental role of variation is ignored. Here we develop a general approach to modeling heterogeneous populations with discrete evolutionary time step. The theory is applied to models of natural rotifer population dynamics. We show that under particular conditions the behavior of the inhomogeneous model possesses complex transition regimes, which depends both on the mean and the variance of the initial parameter distribution; the final state of the population depends on the least possible value from the domain of the parameter. The question of population persistence is discussed.
Capturing divergence in dependency trees to improve syntactic projection

Obtaining syntactic parses is an important step in many NLP pipelines. However, most of the world's languages do not have a large amount of syntactically annotated data available for building parsers. Syntactic projection techniques attempt to address this issue by using parallel corpora consisting of resource-poor and resource-rich language pairs, taking advantage of a parser for the resource-rich language and word alignment between the languages to project the parses onto the data for the resource-poor language. These projection methods can suffer, however, when syntactic structures for some sentence pairs in the two languages look quite different. In this paper, we investigate the use of small, parallel, annotated corpora to automatically detect divergent structural patterns between two languages. We then use these detected patterns to improve projection algorithms and dependency parsers, allowing for better performing NLP tools for resource-poor languages, particularly those that may not have large amounts of annotated data necessary for traditional, fully-supervised methods. While this detection process is not exhaustive, we demonstrate that common patterns of divergence can be identified automatically without prior knowledge of a given language pair, and the patterns can be used to improve performance of syntactic projection and parsing.
Interacting acceleration compensation algorithm for tracking maneuvering targets

The two-stage Kalman estimator has been studied for state estimation in the presence of random bias and applied to the tracking of maneuvering targets by treating the target acceleration as a bias vector. Since the target acceleration is considered a bias, the first stage contains a constant velocity motion model and estimates the target position and velocity, while the second stage estimates the target acceleration when a maneuver is detected, the acceleration estimate is used to correct the estimates of the first stage. The interacting acceleration compensation (IAC) algorithm is proposed to overcome the requirement of explicit maneuver detection of the two-stage estimator. The IAC algorithm is viewed as a two-stage estimator having two acceleration models: the zero acceleration of the constant velocity model and a constant acceleration model. The interacting multiple model (IMM) algorithm is used to compute the acceleration estimates that compensate the estimate of the constant velocity filter. Simulation results indicate the tracking performance of the IAC algorithm approaches that of a comparative IMM algorithm while requiring approximately 50% of the computations. >
The Representation of Brightness in Primary Visual Cortex

Although neurons in primary visual cortex are sensitive to the spatial distribution and intensity of light, their responses have not been thought to correlate with the perception of brightness. Indeed, primary visual cortex is often described as an initial processing stage that sends information to higher cortical areas where perception of brightness, color, and form occurs. However, a significant percentage of neurons in primary visual cortex were shown to respond in a manner correlated with perceived brightness, rather than responding strictly to the light level in the receptive fields of the cells. This finding suggests that even at the first stage of visual cortical processing, spatial integration of information yields perceptual qualities that are only indirectly related to the pattern of illumination of the retina.