Single Consistent Set Research Articles

Neutron and gamma multiplicities calculated in the consistent framework of the Hauser-Feshbach Monte Carlo code FIFRELIN

Monte-Carlo simulations to calculate the number of prompt particles emitted during fission were performed using the Fifrelin code and compared to recent experimental data. We show that we are able to reproduce both the neutron and γ-ray multiplicity distributions as a function of the pre-neutron mass of the fission fragments using a single consistent set of parameters. This result was made possible by using an energy-dependent spin cut-off model, driving the initial total angular momentum of the fission fragments, together with microscopic level densities from the HFB plus combinatorial method. We also discuss, how the initial excitation-energy sharing shapes the TKE-dependent γ-ray multiplicity.

Process-Level Modeling Can Simultaneously Explain Secondary Organic Aerosol Evolution in Chambers and Flow Reactors

Secondary organic aerosol (SOA) data gathered in environmental chambers (ECs) have been used extensively to develop parameters to represent SOA formation and evolution. The EC-based parameters are usually constrained to less than one day of photochemical aging but extrapolated to predict SOA aging over much longer timescales in atmospheric models. Recently, SOA has been increasingly studied in oxidation flow reactors (OFRs) over aging timescales of one to multiple days. However, these OFR data have been rarely used to validate or update the EC-based parameters. The simultaneous use of EC and OFR data is challenging because the processes relevant to SOA formation and evolution proceed over very different timescales, and both reactor types exhibit distinct experimental artifacts. In this work, we show that a kinetic SOA chemistry and microphysics model that accounts for various processes, including wall losses, aerosol phase state, heterogeneous oxidation, oligomerization, and new particle formation, can simultaneously explain SOA evolution in EC and OFR experiments, using a single consistent set of SOA parameters. With α-pinene as an example, we first developed parameters by fitting the model output to the measured SOA mass concentration and oxygen-to-carbon (O:C) ratio from an EC experiment (<1 day of aging). We then used these parameters to simulate SOA formation in OFR experiments and found that the model overestimated SOA formation (by a factor of 3-16) over photochemical ages ranging from 0.4 to 13 days, when excluding the abovementioned processes. By comprehensively accounting for these processes, the model was able to explain the observed evolution in SOA mass, composition (i.e., O:C), and size distribution in the OFR experiments. This work suggests that EC and OFR SOA data can be modeled consistently, and a synergistic use of EC and OFR data can aid in developing more refined SOA parameters for use in atmospheric models.

Newborn Screening and Diagnosis of Infants with Congenital Adrenal Hyperplasia

Congenital adrenal hyperplasia (CAH) is an autosomal recessive endocrine disorder which can manifest after birth with ambiguous genitalia and salt-wasting crisis. However, genital ambiguity is not seen in male babies and may be mild in female babies, leading to a missed diagnosis of classical CAH at birth. In this review, we provide a standard operating protocol for routine newborn screening for CAH in Indian settings. A standardization of first tier screening tests with a single consistent set of cut-off values stratified by gestational age is also suggested. The protocol also recommends a two-tier protocol of initial immunoassay/time resolved fluoroimmunoassay followed by liquid chromatography tandem mass spectrometry for confirmation of screen positive babies, wherever feasible. Routine molecular and genetic testing is not essential for establishing the diagnosis in all screen positive babies, but has significant utility in prenatal diagnosis and genetic counseling for future pregnancy.

Incompatible multiple consistent sets of histories and measures of quantumness

In the consistent histories (CH) approach to quantum theory probabilities are assigned to histories subject to a consistency condition of negligible interference. The approach has the feature that a given physical situation admits multiple sets of consistent histories that cannot in general be united into a single consistent set, leading to a number of counter-intuitive or contrary properties if propositions from different consistent sets are combined indiscriminately. An alternative viewpoint is proposed in which multiple consistent sets are classified according to whether or not there exists any unifying probability for combinations of incompatible sets which replicates the consistent histories result when restricted to a single consistent set. A number of examples are exhibited in which this classification can be made, in some cases with the assistance of the Bell, CHSH or Leggett-Garg inequalities together with Fine's theorem. When a unifying probability exists logical deductions in different consistent sets can in fact be combined, an extension of the "single framework rule". It is argued that this classification coincides with intuitive notions of the boundary between classical and quantum regimes and in particular, the absence of a unifying probability for certain combinations of consistent sets is regarded as a measure of the "quantumness" of the system. The proposed approach and results are closely related to recent work on the classification of quasi-probabilities and this connection is discussed.

Systematic Parameterization of Lignin for the Charmm Force Field

Lignin is an abundant aromatic biopolymer within plant cell walls formed through radical coupling chemistry, whose composition and topology can vary greatly depending on the biomass source. Computational modeling provides a complementary approach to traditional experimental techniques to probe lignin interactions, lignin structure, and lignin material properties. However, current modeling approaches are limited based on the subset of lignin chemistries covered by existing lignin force fields. To fill the gap, we developed a comprehensive lignin force field that accounts for more lignin–lignin and lignin–carbohydrate interlinkages than existing lignin force fields, and also greatly expands the lignin monomer chemistries that can be modeled beyond simple alcohols and into the rich mixture of natural lignin varieties. The development of this force field utilizes recent developments in parameterization methodology, and synthesizes them into a workflow that combines target data from multiple molecules simultaneously into a single consistent and comprehensive parameter set. The parameter set represents a significant improvement to alternatives for atomic modeling of diverse lignin topologies, more accurately reproducing experimental observables while also significantly reducing the error relative to quantum calculations. The improved energetics, as well as the rigid adherence to CHARMM parameterization philosophy, enables simulation of lignin within its biological context with greater accuracy than was previously possible. The lignin force field presented here is therefore a crucial first step towards modeling lignin structure across a broad range of environments, including within plant cell walls where lignin is complexed with carbohydrates and deconstructed by bacterial or fungal enzymes, or as it exists within industrial solvent mixtures. Future simulations enabled by this updated lignin force field will thus lead to better chemical and structural understanding of lignin, providing new insight into its role in biomass recalcitrance or probing the potential for lignin to be used within industrial processes.

A state parameter-based model for static recrystallization interacting with precipitation

In the present work, we develop a state parameter-based model for the treatment of simultaneous precipitation and recrystallization based on a single-parameter representation of the total dislocation density and a multi-particle multi-component framework for precipitation kinetics. In contrast to conventional approaches, the interaction of particles with recrystallization is described with a non-zero grain boundary mobility even for the case where the Zener pressure exceeds the driving pressure for recrystallization. The model successfully reproduces the experimentally observed particle-induced recrystallization stasis and subsequent continuation in micro-alloyed steel with a single consistent set of input parameters. In addition, as a state parameter-based approach, our model naturally supports introspection into the physical mechanisms governing the competing recrystallization and recovery processes.

Global Kinetic Analysis of Mammalian E3 Reveals pH-dependent NAD+/NADH Regulation, Physiological Kinetic Reversibility, and Catalytic Optimum

Mammalian E3 is an essential mitochondrial enzyme responsible for catalyzing the terminal reaction in the oxidative catabolism of several metabolites. E3 is a key regulator of metabolic fuel selection as a component of the pyruvate dehydrogenase complex (PDHc). E3 regulates PDHc activity by altering the affinity of pyruvate dehydrogenase kinase, an inhibitor of the enzyme complex, through changes in reduction and acetylation state of lipoamide moieties set by the NAD(+)/NADH ratio. Thus, an accurate kinetic model of E3 is needed to predict overall mammalian PDHc activity. Here, we have combined numerous literature data sets and new equilibrium spectroscopic experiments with a multitude of independently collected forward and reverse steady-state kinetic assays using pig heart E3. The latter kinetic assays demonstrate a pH-dependent transition of NAD(+) activation to inhibition, shown here, to our knowledge, for the first time in a single consistent data set. Experimental data were analyzed to yield a thermodynamically constrained four-redox-state model of E3 that simulates pH-dependent activation/inhibition and active site redox states for various conditions. The developed model was used to determine substrate/product conditions that give maximal E3 rates and show that, due to non-Michaelis-Menten behavior, the maximal flux is different compared with the classically defined kcat.

A practical method for the estimation of oil and water mutual solubilities

A simple model is proposed for the calculation of oil and water mutual solubilities as a function of temperature using the hydrocarbon specific gravity and Watson-K factor as correlating parameters. The model parameters were determined using a single consistent set of high quality solubility data collected at the water or hydrocarbon saturation pressures at temperatures from 273K and 573K but primarily from 298K to 398K. The hydrocarbon in water solubilities ranged over 11 orders of magnitude while the water in hydrocarbons solubilities ranged over 4 orders of magnitude. Hydrocarbon types ranged from low molecular weight paraffins such as n-pentane to heavy aromatics such as anthracene. The average absolute error in the estimated solubilities of water in hydrocarbons over 621 data points was 34% and approached the suggested underlying uncertainty in the reference data (30%). The average absolute error in the estimated solubilities of hydrocarbons in water over 964 data points was 88% and exceeded the suggested underlying uncertainty in the reference data (30%).The model can be extended to higher temperatures using a procedure based on activity coefficients or equations of state and is easily adapted to work with ill-defined hydrocarbon mixtures. Prediction and correlation of solubilities of water in kerosene, heavy oils, and bitumen were made at temperatures, pressures, and compositions far removed from the original data used for model construction. The correlation failed near the critical temperature of water because under these conditions, the properties hydrocarbon-rich phases in the mixtures on which the correlation is based (Type II and Type IIIa phase behaviour according to the van Konynenburg and Scott naming scheme) and those of water+heavy hydrocarbons (Type IIIb phase behaviour) diverge. A separate NRTL based correlation is presented for the mutual solubility of water+heavy oils at temperatures close to the critical temperature of water.

Reconciling intuitive physics and Newtonian mechanics for colliding objects.

People have strong intuitions about the influence objects exert upon one another when they collide. Because people's judgments appear to deviate from Newtonian mechanics, psychologists have suggested that people depend on a variety of task-specific heuristics. This leaves open the question of how these heuristics could be chosen, and how to integrate them into a unified model that can explain human judgments across a wide range of physical reasoning tasks. We propose an alternative framework, in which people's judgments are based on optimal statistical inference over a Newtonian physical model that incorporates sensory noise and intrinsic uncertainty about the physical properties of the objects being viewed. This noisy Newton framework can be applied to a multitude of judgments, with people's answers determined by the uncertainty they have for physical variables and the constraints of Newtonian mechanics. We investigate a range of effects in mass judgments that have been taken as strong evidence for heuristic use and show that they are well explained by the interplay between Newtonian constraints and sensory uncertainty. We also consider an extended model that handles causality judgments, and obtain good quantitative agreement with human judgments across tasks that involve different judgment types with a single consistent set of parameters.

Article I. Multi-platform Automated Software Building and Packaging

One of the major goals of the EMI (European Middleware Initiative) project is the integration of several components of the pre-existing middleware (ARC, gLite, UNICORE and dCache) into a single consistent set of packages with uniform distributions and repositories. Those individual middleware projects have been developed in the last decade by tens of development teams and before EMI were all built and tested using different tools and dedicated services. The software, millions of lines of code, is written in several programming languages and supports multiple platforms. Therefore a viable solution ought to be able to build and test applications on multiple programming languages using common dependencies on all selected platforms. It should, in addition, package the resulting software in formats compatible with the popular Linux distributions, such as Fedora and Debian, and store them in repositories from which all EMI software can be accessed and installed in a uniform way. Despite this highly heterogeneous initial situation, a single common solution, with the aim of quickly automating the integration of the middleware products, had to be selected and implemented in a few months after the beginning of the EMI project. Because of the previous knowledge and the short time available in which to provide this common solution, the ETICS service, where the gLite middleware was already built for years, was selected. This contribution describes how the team in charge of providing a common EMI build and packaging infrastructure to the whole project has developed a homogeneous solution for releasing and packaging the EMI components from the initial set of tools used by the earlier middleware projects. An important element of the presentation is the developers experience and feedback on converging on ETICS and on the on-going work in order to finally add more widely used and supported build and packaging solutions of the Linux platforms

Multi-platform Automated Software Building and Packaging

One of the major goals of the EMI (European Middleware Initiative) project is the integration of several components of the pre-existing middleware (ARC, gLite, UNICORE and dCache) into a single consistent set of packages with uniform distributions and repositories. Those individual middleware projects have been developed in the last decade by tens of development teams and before EMI were all built and tested using different tools and dedicated services. The software, millions of lines of code, is written in several programming languages and supports multiple platforms. Therefore a viable solution ought to be able to build and test applications on multiple programming languages using common dependencies on all selected platforms. It should, in addition, package the resulting software in formats compatible with the popular Linux distributions, such as Fedora and Debian, and store them in repositories from which all EMI software can be accessed and installed in a uniform way. Despite this highly heterogeneous initial situation, a single common solution, with the aim of quickly automating the integration of the middleware products, had to be selected and implemented in a few months after the beginning of the EMI project. Because of the previous knowledge and the short time available in which to provide this common solution, the ETICS service, where the gLite middleware was already built for years, was selected. This contribution describes how the team in charge of providing a common EMI build and packaging infrastructure to the whole project has developed a homogeneous solution for releasing and packaging the EMI components from the initial set of tools used by the earlier middleware projects. An important element of the presentation is the developers experience and feedback on converging on ETICS and on the on-going work in order to finally add more widely used and supported build and packaging solutions of the Linux platforms

A Southern Ocean dietary database

Knowledge of the trophic functioning of Southern Ocean ecosystems is critical to their understanding and management. Marine ecosystem models, often used to explore the potential impacts of human disturbance and climate change, and for fisheries stock assessments, generally rely on suitable data to underpin the parameterization of taxon attributes and diets. Diet-related data from published and unpublished data sets and studies were collated into a single consistent data set, circum-Antarctic in scope, with two principal tables. The first table relates to direct sampling methods of dietary assessment, including gut, scat, and bolus content analyses, stomach flushing, and observed feeding. It currently comprises ∼25 000 records from 300 studies and includes information on >1000 taxa. The second table is a compilation of stable isotope values (currently 1500 records from 20 studies, covering 200 taxa). Each record in these two tables includes details such as the location and date of sampling, predator size a...

ChemInform Abstract: Experimental Determination of the S1 Torsional Potential of 9,9′- Bianthryl in 2-Methyl-butane by Simultaneous Franck-Condon and Band Shape Analysis of Temperature Dependent Optical Fluorescence Spectra.

Optical fluorescence spectra of anthracene (AN) and of 9,9’‐bianthryl (BA) have been measured in the apolar solvent 2‐methyl‐butane (2MB) at seven different temperatures in the range 123 K to 298 K. The AN spectra are strongly structured and consist of simple Franck–Condon (FC) progressions. The BA spectra on the other hand are broad and show unusual temperature dependencies. These effects are interpreted within a two state model with five vibrational and one torsional degree of freedom. A FC analysis is carried out using vibronic band shape functions which are convolutions of two functions. The first one is a Gaussian representing the spectral broadening due to librations and intermolecular interactions. The second one results from a semiclassical treatment of the intramolecular torsional mode (large amplitude motion, LAM). Optical transitions are assumed to occur from ensembles which are thermally equilibrated with respect to their nuclear degrees of freedom. The Boltzmann distribution with respect to the LAM potentials in combination with a change of the transition frequency as a function of the torsional angle φ is identified as the predominant broadening mechanism. The LAM potentials in the S0 and S1 state are represented by a three parameter cosine series. A nonlinear least‐squares fit of the experimental spectra leads to a single consistent set of model parameters valid for all temperatures. The S1 double minimum LAM potential of BA in 2MB is found to have minima at φeq=62° (and 118°) and a local barrier at φ=90° of 255 cm−1.

On the logic of preference and judgment aggregation

Agents that must reach agreements with other agents need to reason about how their preferences, judgments, and beliefs might be aggregated with those of others by the social choice mechanisms that govern their interactions. The emerging field of judgment aggregation studies aggregation from a logical perspective, and considers how multiple sets of logical formulae can be aggregated to a single consistent set. As a special case, judgment aggregation can be seen to subsume classical preference aggregation. We present a modal logic that is intended to support reasoning about judgment aggregation scenarios (and hence, as a special case, about preference aggregation): the logical language is interpreted directly in judgment aggregation rules. We present a sound and complete axiomatisation. We show that the logic can express aggregation rules such as majority voting; rule properties such as independence; and results such as the discursive paradox, Arrow's theorem and Condorcet's paradox--which are derivable as formal theorems of the logic. The logic is parameterised in such a way that it can be used as a general framework for comparing the logical properties of different types of aggregation--including classical preference aggregation. As a case study we present a logical study of, including a formal proof of, the neutrality lemma, the main ingredient in a well-known proof of Arrow's theorem.

The Distribution of Collisionally Induced Blue Stragglers in the Color‐Magnitude Diagram

A primary production mechanism for blue stragglers in globular clusters is thought to be collisionally induced mergers, perhaps mediated by dynamical encounters involving binary stars. We model the formation and evolution of such blue stragglers and produce theoretical distributions of them in the color-magnitude diagram. We use a crude representation of cluster dynamics and detailed binary-single star encounter simulations to produce cross sections and rates for a variety of collisions. The results of the collisions are determined on the basis of smoothed-particle hydrodynamics simulations of realistic star models. The evolution of the collision products are then followed in detail using the Yale stellar evolution code. We present our results in the form of distributions in the observed color-magnitude diagram. We use our results to explore the effects of a variety of input assumptions on the number and kind of blue stragglers created by collisions. In particular, we describe the changes in the blue straggler distribution that result from using realistic collision products rather than the fully mixed assumption, and from changes in assumptions about the number and orbital-period distribution of the primordial binary population. We then apply our models to existing data from the core of M3, where the large blue straggler population is thought to be dominated by collision products. We find that we have difficulty successfully modeling the observed blue stragglers under a single consistent set of assumptions. However, if three particularly bright blue stragglers are considered to be part of a different observed population (as has been suggested previously for other clusters) and left out of the population, the remainder can be successfully modeled using realistic encounter products and assuming a 20% binary fraction with a plausible period distribution. Finally, we suggest a variety of routes toward a more comprehensive understanding of the blue straggler phenomenon.

Optimization of pseudomorphic HEMT's supported by numerical simulations

Measurements and simulations of three different pseudomorphic high electron mobility transistors (PHEMT's) are presented. The PHEMT's possess the same epitaxial structure but different geometrical properties. For the simulations, the generic device simulator MINIMOS-NT is employed. This simulator is not restricted to planar device surfaces but is able to model complex surface topologies including the effect of passivating dielectric layers. Mixed hydrodynamic and drift-diffusion simulations are demonstrated. They include the DC characteristics as well as the bias-dependent gate capacitances. Thus, bias-dependent current-gain cutoff frequencies f/sub T/ can be calculated. The results compare very well with the values obtained by small-signal parameter extractions from S-parameter measurements. Although a single consistent set of parameters is used for the simulations of all three devices, their characteristics are reproduced with an accuracy to our knowledge not reported before. Therefore, the DC and RF properties of PHEMT's with geometries significantly different from the measured devices can be reliably predicted.

Surface corrugation effects on the adsorption dynamics of xenon on Pt(110)−(1 × 2)

The adsorption probability of xenon on Pt(110)(1 × 2) shows a strong dependence on both the polar (θ i) and aximuthal angles of incidence. For atoms incident along the (11̄0) direction the adsorption probability increases slowly with increasing angle of incidence, scaling as E i, cos 0.5θ, whereas along the (100) azimuth it decreases with increasing angle of incidence, exhibiting “negative” energy scaling. The hard cube washboard model does not account quantitatively for these differences with a single consistent set of parameters.

Theoretical interpretation of the swelling of elastomers

The swelling dilation moduli reported in the preceding paper are here analyzed with use of a recently proposed theory of rubber elasticity. The theory predicts that the elastic equation of state is dependent on solution thermodynamic parameters, in agreement with the observations. It is successful in accounting for the solvent effects, which is a step forward; it also succeeds in predicting that the Mooney-Rivlin C 2 term decreases with increasing extent of swelling. Unfortunately, agreement with experiment cannot be achieved with a single consistent set of parameters

Experimental determination of the S1 torsional potential of 9,9′-bianthryl in 2-methyl-butane by simultaneous Franck–Condon and band shape analysis of temperature dependent optical fluorescence spectra

Optical fluorescence spectra of anthracene (AN) and of 9,9′-bianthryl (BA) have been measured in the apolar solvent 2-methyl-butane (2MB) at seven different temperatures in the range 123 K to 298 K. The AN spectra are strongly structured and consist of simple Franck–Condon (FC) progressions. The BA spectra on the other hand are broad and show unusual temperature dependencies. These effects are interpreted within a two state model with five vibrational and one torsional degree of freedom. A FC analysis is carried out using vibronic band shape functions which are convolutions of two functions. The first one is a Gaussian representing the spectral broadening due to librations and intermolecular interactions. The second one results from a semiclassical treatment of the intramolecular torsional mode (large amplitude motion, LAM). Optical transitions are assumed to occur from ensembles which are thermally equilibrated with respect to their nuclear degrees of freedom. The Boltzmann distribution with respect to the LAM potentials in combination with a change of the transition frequency as a function of the torsional angle φ is identified as the predominant broadening mechanism. The LAM potentials in the S0 and S1 state are represented by a three parameter cosine series. A nonlinear least-squares fit of the experimental spectra leads to a single consistent set of model parameters valid for all temperatures. The S1 double minimum LAM potential of BA in 2MB is found to have minima at φeq=62° (and 118°) and a local barrier at φ=90° of 255 cm−1.

An abductive theory of legal issues

A normative theory of legal issues, argument moves and clear cases is presented in which abduction, rather than deduction, is of central importance. The theory is a refinement of Fiedler's constructive view of legal reasoning. Like legal positivism, the theory elaborates the concept of a clear case, but here clearness is defined relative to a set of competing interpretations of the law, rather than a single consistent set of “valid” rules. A computational model for the theory is described, which uses an ATMS reason maintenance system to implement abduction. Finally, the theory is compared with Anne Gardner's program for spotting issues in offer and acceptance law school examination questions.