cssi/SciSciGPT-SciSciNet huggingface dataset:
How coupling determines the entrainment of circadian clocks

Autonomous circadian clocks drive daily rhythms in physiology and behaviour. A network of coupled neurons, the suprachiasmatic nucleus (SCN), serves as a robust self-sustained circadian pacemaker. Synchronization of this timer to the environmental light-dark cycle is crucial for an organism’s fitness. In a recent theoretical and experimental study it was shown that coupling governs the entrainment range of circadian clocks. We apply the theory of coupled oscillators to analyse how diffusive and mean-field coupling affects the entrainment range of interacting cells. Mean-field coupling leads to amplitude expansion of weak oscillators and, as a result, reduces the entrainment range. We also show that coupling determines the rigidity of the synchronized SCN network, i.e. the relaxation rates upon perturbation. Our simulations and analytical calculations using generic oscillator models help to elucidate how coupling determines the entrainment of the SCN. Our theoretical framework helps to interpret experimental data.
Fuel choice, indoor air pollution and children's health.

Much of the population in developing countries uses firewood for cooking. The resulting indoor air pollution has severe health consequences for children who are close to the fire while their mothers cook. We use survey data from Guatemala to examine the effects of firewood consumption on the health of children up to five years of age. We also investigate the impact of cooking inside the home, the importance of a mother cooking while caring for her children and the role played by the smoke permeability of housing construction materials. We find that children living in households that use more wood, and where exposure to indoor air pollution is higher because the mother cooks while caring for children or because cooking takes place inside, are more likely to have symptoms of respiratory infection. Simulations indicate that policies that target cooking habits in order to directly reduce exposure, particularly by reducing the number of women who simultaneously cook and care for children, may be more effective for improving young children's health than policies to accelerate the adoption of gas stoves.
The IRC +10216 circumstellar shell

Spectroscopic studies of IRC +10 216 reveal numerous molecular species and at least two grain species. To define the composition of the ejected material and confirm the activity of chemical processes in the expanding shell, it is necessary to integrate infrared and microwave spectroscopic results with multi-spectral spatial mapping.
Learning about spin-one-half fields

It is hard to understand spin-one-half fields without reading Weinberg. This paper is a pedagogical footnote to his formalism with an emphasis on the boost matrix, spinors and Majorana fields.
Verification of the proposed equation for calculation of the forces on a sphere accelerating in a viscous fluid

The equation which was proposed for the calculation of forces on a sphere accelerating in a viscous fluid is verified by comparing the velocities of spheres falling under gravity in a viscous fluid with those calculated from the equation.
Effective modeling/analysis of isothermal phase change problems with emphasis on representative enthalpy architectures and finite elements

Elements 490 . 3 w 7 f ' Raju R. Namburu I ' Graduate Research Assistant A modelinglanalysis approach with special reference to a class of isothermal phase change is described. Emphasis i s placed on representative enthalpy architectures which introduce some added advantages with only minor modifications to the generalized y-family of representations proposed originally for general solidification problems by Tamma and Namburu [ 5 I. Numerical test models are presented to illustrate the applicabiliry to a class of isothermal phase change situations.
MDTraj: A Modern Open Library for the Analysis of Molecular Dynamics Trajectories

As molecular dynamics (MD) simulations continue to evolve into powerful computational tools for studying complex biomolecular systems, the necessity of flexible and easy-to-use software tools for the analysis of these simulations is growing. We have developed MDTraj, a modern, lightweight, and fast software package for analyzing MD simulations. MDTraj reads and writes trajectory data in a wide variety of commonly used formats. It provides a large number of trajectory analysis capabilities including minimal root-mean-square-deviation calculations, secondary structure assignment, and the extraction of common order parameters. The package has a strong focus on interoperability with the wider scientific Python ecosystem, bridging the gap between MD data and the rapidly growing collection of industry-standard statistical analysis and visualization tools in Python. MDTraj is a powerful and user-friendly software package that simplifies the analysis of MD data and connects these datasets with the modern interactive data science software ecosystem in Python.
Abelian gauge fluxes and local models in F-theory

We analyze the Abelian gauge fluxes in local F-theory models with G S = SU(6) and SO(10). For the case of G S = SO(10), there is a no-go theorem which states that for an exotic-free spectrum, there are no solutions for U(1)2 gauge fluxes. We explicitly construct the U(1)2 gauge fluxes with an exotic-free bulk spectrum for the case of G S = SU(6). We also analyze the conditions for the curves supporting the given field content and discuss non-minimal spectra of the MSSM with doublet-triplet splitting.
Applying disease management strategies to medicare

Medicare coverage begins for many when they have already developed one or more chronic diseases, and it often pays for the latest and costliest phases. Population-based disease modeling, patient screening, and monitoring would be appropriate interventions for chronic renal disease. Patients who have not yet advanced to end-stage renal disease would benefit from management of diabetes and hypertension, avoidance of nephrotoxic substances, and better preparation for dialysis. Administrative support could take the form of clinical guidelines, physician-led multidisciplinary teams, integrated delivery systems, provider and patient education, and new information technologies. Medicare reflects the long-term public perspective, and thus should further this new direction by supporting education, reimbursing for prevention efforts and allied health services, encouraging efficiency, and monitoring cost and quality outcomes.
Nonparametric Efficiency Analysis for Coffee Farms in Puerto Rico

Nonparametric Efficiency Analysis for Coffee Farms in Puerto Rico Alexandra Gregory Kansas State University Department of Agricultural Economics 400 Waters Hall Manhattan, Kansas 66506-4011 agregory@agecon.ksu.edu Allen M. Featherstone Kansas State University Department of Agricultural Economics Waters Hall Manhattan, Kansas 66506-4011
THE ORIGIN OF ANGULAR MOMENTUM IN DARK MATTER HALOS

We propose a new explanation for the origin of angular momentum in galaxies and their dark halos, in which the halos obtain their spin through the cumulative acquisition of angular momentum from satellite accretion. In our model, the buildup of angular momentum is a random walk process associated with the mass assembly history of the halo's major progenitor. We assume no correlation between the angular momenta of accreted objects. The main role of tidal torques in this approach is to produce the random tangential velocities of merging satellites. Using the extended Press-Schechter approximation, we calculate the growth of mass, angular momentum, and spin parameter λ for many halos. Our random walk model reproduces the key features of the angular momentum of halos found in ΛCDM N-body simulations: a lognormal distribution in λ with an average of ≈ 0.045 and dispersion σλ = 0.56, independent of mass and redshift. The evolution of the spin parameter in individual halos in this model is quite different from the steady increase with time of angular momentum in the tidal torque picture. We find both in N-body simulations and in our random walk model that the value of λ changes significantly with time for a halo's major progenitor. It typically has a sharp increase due to major mergers and a steady decline during periods of gradual accretion of small satellites. The model predicts that, on average, the λ of ~1012 M☉ halos that had major mergers after redshift z = 3 should be substantially larger than the λ of those that did not. Perhaps surprisingly, this suggests that halos that host later forming elliptical galaxies should rotate faster than halos of spiral galaxies.
Aqueous-phase, thermal Pauson-Khand reactions in the presence of surfactants

Abstract Efficient stoichiometric Pauson–Khand reactions were realized in water as the only solvent, and in the presence of surfactants as additives. Use of the cationic surfactant CTAB provided good yields of cyclopentenones from the thermal reactions of pre-formed dicobalthexacarbonyl complexes of enynes and alkynes. The water-CTAB medium was found to be less effective with Co 4 (CO) 12 as the promoter of the reaction. Incidentally, these results have provided a strictly water-based PKR protocol under very mild and convenient conditions.
Cognitive Dissonance in Endodontics

Cognitive dissonance is the existence of views, attitudes, or beliefs which are inconsistent or incompatible with one another but, nonetheless, are held simultaneously by the same person. In a penetrating article, Edwin G. Boring (1), Edgar Pierce Professor of Psychology Emeritus at Harvard University, has documented the existence of cognitive dissonance among scientists who, after all, he said, turn out to be human. One of the graphic examples offered is the persistence of smoking, despite evidence that it is hazardous to life itself. To rationalize, the smoker must change his cognition, thereby minimizing the scare about lung cancer, suppress or ignore the dissonance, or change his behavior by giving up smoking. Is cognitive dissonance present in endodontics? It is our belief that, as scientific evidence accumulates, a greater and greater dissonance is emerging in both the theory and the practice of endodontics. At least, this is true for us, and we would like to share our dissonance with others in the scientific community who perhaps have similar but unexpressed views. It has long been held that if the three basic principles—the so-called “endodontic triad”—are followed faithfully, the end result of endodontic treatment must be successful (2). These three “principles” are (a) thorough debridement of the root canal, (b) sterilization of the root canal, and (c) complete obturation of the root canal. Put down as a simple formula, it would be a! b! c" endodontic success. In endodontic therapy, the a ! b ! c formula for success has been taught in most dental schools as the only sure way to achieve a lasting and permanent result. Deviations from this formula are almost certain to result in failure. So far, no dissonance. However, some dissonance begins to creep in when the dental student or general practitioner (or even the experienced endodontist, for that matter) follows the a ! b ! c formula and failure ensues (Fig. 1). Usually, the dissonance is resolved quickly by the rationalization that, somehow, there has been a break in adherence to the a! b ! c formula. For example, maybe a small amount of necrotic tissue was left in the root canal and somehow escaped being removed, or perhaps the negative culture obtained was a false negative and there were some microorganisms lurking in hidden recesses just waiting for the opportunity to emerge and “vent their spleens” on the periapical tissues after treatment was completed. Perhaps the canal was not completely obturated and there were minute voids between the root filling and the dentinal wall, or perhaps the canal was overfilled and the filling material was irritating. The possibilities are numerous. Conversely, dissonance also arises when, through intention or neglect, the formula is not followed and success results anyway (Fig. 2). How can this be explained rationally? The cognitive dissonance rears its ugly head when we examine each part of the triad, as we shall now do.
Enumerating flux vacua with enhanced symmetries

We study properties of flux vacua in type IIB string theory in several simple but illustrative models. We initiate the study of the relative frequencies of vacua with vanishing superpotential W = 0 and with certain discrete symmetries. For the models we investigate we also compute the overall rate of growth of the number of vacua as a function of the D3-brane charge associated to the fluxes, and the distribution of vacua on the moduli space. The latter two questions can also be addressed by the statistical theory developed by Ashok, Denef and Douglas, and our results are in good agreement with their predictions. Analysis of the first two questions requires methods which are more number-theoretic in nature. We develop some elementary techniques of this type, which are based on arithmetic properties of the periods of the compactification geometry at the points in moduli space where the flux vacua are located.
How Long Do Junk Bonds Spend in Default

This paper analyzes junk bond defaults during 1980 to 1991 to determine which factors affect the length of time spent in default. Bondholder holdouts are not a significant problem, as firms with proportionately more bonds have shorter default spells. In contrast, bank debt is associated with slower restructurings. Bargaining problems arising from contingent liabilities, lawsuits, and size delay the process, although multiple bond classes do not. Neither information problems nor firm value appear to matter. HLTs do not resolve their defaults at a significantly faster pace. Defaults tend to take less time in the 1990s, despite Drexel's disappearance from the market.
Alignment between green supply chain management strategy and business strategy

It is generally recognised that a company’s green supply chain management strategy is effective to the extent that it is aligned with business strategy. Prior research argues that green supply chain management strategy enhances organisational performance, and provides the company with a competitive advantage. However, identification of appropriate green supply chain management – business strategy alignments and their impact on business performance have received relatively little conceptual attention. Given a conceptualisation of green supply chain management strategy through Simpson and Samson’s typology and business strategy through Miles and Snow’s typology, this paper: 1 develops a conceptual framework for aligning green supply chain management strategy with business strategy 2 identifies from prior research, four green supply chain management strategies (risk-based, efficiency-based, innovation-based and closed-loop) that theoretically aligns with Miles and Snow’s strategic business types (reactors, defenders, analysers and prospectors) 3 identifies which green supply chain management – business strategic alignments impact business performance. Implications, conclusions, limitations and future research opportunities are discussed.
Rare Disasters and Exchange Rates

We propose a new model of exchange rates, which yields a theory of the forward premium puzzle. Our explanation combines two ingredients: the possibility of rare economic disasters, and an asset view of the exchange rate. Our model is frictionless, has complete markets, and works for an arbitrary number of countries. In the model, rare worldwide disasters can occur and affect each country’s productivity. Each country’s exposure to disaster risk varies over time according to a mean-reverting process. Ri sky countries command high risk premia: they feature a depreciated exchange rate and a high interest rate. As their risk premium mean reverts, their exchange rate appreciates. Therefore, currencies of high interest rate countries appreciate on average. To make the notion of disaster risk more implementable, we show how options prices might in principle uncover latent disaster risk, and help forecast exchange rate movements. We then extend the framework to incorporate two factors: a disaster risk factor, and a business cycle factor. We calibrate the model and obtain quantitatively realistic values for the volatility of the exchange rate, the forward premium puzzle regression coefficients, and near-random walk exchange rate dynamics. Finally, we solve a model of stock markets across countries, which yields a series of predictions about the joint behavior of exchange rates, bonds, options and stocks across countries. The evidence from the options market appears to be supportive of the model. (JEL: E43, E44, F31, G12, G15)
O.M.W. Sprague (the man who “wrote the book” on financial crises) and the founding of the Federal Reserve ☆

Abstract O.M.W. Sprague was America's leading expert on financial crises when America was debating establishing the Federal Reserve. His History of Crises under the National Banking System is the most enduring intellectual legacy of the National Monetary Commission; a still frequently cited classic. Since the Commission recommended a central bank, and its recommendation after some modifications became the Federal Reserve System, it might be assumed that Sprague was a strong supporter of establishing a central bank. But he was not. Initially, Sprague favored far more limited reforms, a position that he did not abandon until the Federal Reserve became a fait accompli. Here I discuss the sources of Sprague's opposition to a central bank and the relationship of that opposition to his understanding of the history and structure of the American banking system at the turn of the nineteenth century.
Crystal Structure of FePb4Sb6Se14 and its Structural Relationship with FePb3Sb4Se10

Single crystals of FePb4Sb6Se14, were obtained from solid-state combination of high purity elemental powders at 873K for three days. Single crystal X-ray structure determination revealed that the compound crystallizes in the monoclinic space group P21/c (no. 14) and adopts the structure of Jamesonite (FePb4Sb6S14). The structure contains two crystallographically independent lead atoms with monocapped and bicapped trigonal prismatic coordinations, three antimony atoms located in a distorted octahedral environment and one iron atom occupying a flattened octahedral coordination. Neighboring monocapped and bicapped trigonal prims around lead atoms share faces and edges to build a corrugated layer parallel to the ac plane. Octahedrally coordinated antimony atoms share edges to form one-dimensional (1D) {SbSe}∞ ribbons connecting adjacent corrugated layers. The distortion of the octahedral coordination around antimony atoms within the {SbSe}∞ ribbons with the longest bond pointing towards the center of the ribbon, suggests the stereochemical activity of antimony lone-pairs with their electron clouds pointing towards the center of the {SbSe}∞ ribbon. The three dimensional framework resulting from the connectivity between the corrugated layers and the {SbSe}∞ ribbons, contains isolated cylindrical voids parallel to [100] which are filled by a 1D FenSe4n+2 straight chain of edge-sharing FeSe6 octahedra. The crystal structure of FePb4Sb6Se14 is closely related to that of FePb3Sb4Se10 as they are formed by similar building units with different sizes.
A qualitative descriptive study of self‐management issues in people with long‐term intermittent urinary catheters

wilde m.h., brasch j. & zhang y. (2011) A qualitative descriptive study of self-management issues in people with long-term intermittent urinary catheters. Journal of Advanced Nursing67(6), 1254–1263. Abstract Aim. The study was to identify and describe issues of intermittent urinary catheter users for future self-management research and/or training programmes. Background. Limited studies were found of how people using clean intermittent catheterization manage their daily routines or troubleshoot problems. Self-management research related to intermittent catheterization could lead to improved compliance with the method and better quality of life. Method. This qualitative descriptive study involved in-depth tape-recorded telephone interviews in 2008–2009 with 34 people in the United States of America using permanent intermittent catheterization, mostly individuals with spinal cord injury or multiple sclerosis. Recruitment was through Internet sites where individuals could link to the study website and then contact the researchers. The sample included 13 men and 21 women aged 21–72 years (mean 42 years). Content analysis for qualitative data involved iterative comparisons of transcripts, summaries and memos. Coding, key quotes and tables were developed to determine themes. Findings. Six major themes were identified: Knowing the Body, Practising Intermittent Catheterization, Limited Options in Catheters and Equipment, Inaccessible Bathrooms, Hassles, and Adjustment in Making Intermittent Catheterization a Part of Life. While some persons had choices in catheters, many did not because of insurance constraints. Some individuals developed knowledge of how to balance the procedure with fluid intake and activities. Conclusion. The lack of acceptable bathrooms can interfere with being able to go to work, travel or be with friends and family. All using intermittent catheterization should have adequate insurance coverage when this is needed. Research into training programmes could incorporate knowledge of experienced users.
Dust-driven Dynamos in Accretion Disks

Magnetically driven astrophysical jets are related to accretion and involve toroidal magnetic field pressure inflating poloidal magnetic field flux surfaces. Examination of particle motion in combined gravitational and magnetic fields shows that these astrophysical jet toroidal and poloidal magnetic fields can be powered by the gravitational energy liberated by accreting dust grains that have become positively charged by emitting photo-electrons. Because a dust grain experiences magnetic forces after becoming charged, but not before, charging can cause irreversible trapping of the grain, so dust accretion is a consequence of charging. Furthermore, charging causes canonical angular momentum to replace mechanical angular momentum as the relevant constant of the motion. The resulting effective potential has three distinct classes of accreting particles distinguished by canonical angular momentum, namely (1) "cyclotron-orbit," (2) "Speiser-orbit," and (3) "zero canonical angular momentum" particles. Electrons and ions are of class 1, but depending on mass and initial orbit inclination, dust grains can be of any class. Light-weight dust grains develop class 1 orbits such that the grains are confined to nested poloidal flux surfaces, whereas grains with a critical weight such that they experience comparable gravitational and magnetic forces can develop class 2 or class 3 orbits, respectively producing poloidal and toroidal field dynamos.
MMBIRFinder: a tool to detect microhomology-mediated break-induced replication

The introduction of next-generation sequencing technologies has radically changed the way we view structural genetic events. Microhomology-mediated break-induced replication (MMBIR) is just one of the many mechanisms that can cause genomic destabilization that may lead to cancer. Although the mechanism for MMBIR remains unclear, it has been shown that MMBIR is typically associated with template-switching events. Currently, to our knowledge, there is no existing bioinformatics tool to detect these template-switching events. We have developed MMBIRFinder, a method that detects template-switching events associated with MMBIR from whole-genome sequenced data. MMBIRFinder uses a half-read alignment approach to identify potential regions of interest. Clustering of these potential regions helps narrow the search space to regions with strong evidence. Subsequent local alignments identify the template-switching events with single-nucleotide accuracy. Using simulated data, MMBIRFinder identified 83 percent of the MMBIR regions within a five nucleotide tolerance. Using real data, MMBIRFinder identified 16 MMBIR regions on a normal breast tissue data sample and 51 MMBIR regions on a triple-negative breast cancer tumor sample resulting in detection of 37 novel template-switching events. Finally, we identified template-switching events residing in the promoter region of seven genes that have been implicated in breast cancer. The program is freely available for download at https://github.com/msegar/MMBIRFinder.
On the minimum ropelength of knots and links

The ropelength of a knot is the quotient of its length by its thickness, the radius of the largest embedded normal tube around the knot. We prove existence and regularity for ropelength minimizers in any knot or link type; these are C 1,1 curves, but need not be smoother. We improve the lower bound for the ropelength of a nontrivial knot, and establish new ropelength bounds for small knots and links, including some which are sharp.
ONE-STEP SYNTHESIS OF TRIFLUOROMETHYL- AND OF METHOXY-SUBSTITUTED BENZYNE PRECURSORS

(1990). ONE-STEP SYNTHESIS OF TRIFLUOROMETHYL- AND OF METHOXY-SUBSTITUTED BENZYNE PRECURSORS. Organic Preparations and Procedures International: Vol. 22, No. 6, pp. 747-753.
Kinematics of solid particles in a turbulent protoplanetary disc

We perform numerical simulations of solid particle motion in a shearing box model of a protoplanetary disc. The accretion flow is turbulent due to the action of the magnetorotational instability. Aerodynamic drag on the particles is modelled using the Epstein law with the gas velocity interpolated to the particle position. The effect of the magnetohydrodynamic turbulence on particle velocity dispersions is quantified for solids of different stopping times ts, or equivalently, different sizes. The anisotropy of the turbulence is reflected upon the dispersions of the particle velocity components, with the radial component larger than both the azimuthal and vertical components for particles larger than � 10 cm (assuming minimum-mass solar nebula conditions at 5 AU). The dispersion of the particle velocity magnitude, as well as that of the radial and azimuthal components, as functions of stopping time, agree with previous analytical results for isotropic turbulence. The relative speed between pairs of particles with the same value of ts decays faster with decreasing separation than in the case of solids with different stopping time. Correlations in the particle number density introduce a non-uniform spatial distribution of solids in the 10 to 100 cm size range. Any clump of particles is disrupted by the turbulence in less than one tenth of an orbital period, and the maximally concentrated clumps are stable against self-gravitational collapse.
Lectures on 2D Yang-Mills Theory, Equivariant Cohomology and Topological Field Theories

These are expository lectures reviewing (1) recent developments in two-dimensional YangMills theory and (2) the construction of topological field theory Lagrangians. Topological field theory is discussed from the point of view of infinite-dimensional differential geometry. We emphasize the unifying role of equivariant cohomology both as the underlying principle in the formulation of BRST transformation laws and as a central concept in the geometrical interpretation of topological field theory path integrals.
Cryptographic extraction and key derivation: the HKDF scheme

In spite of the central role of key derivation functions (KDF) in applied cryptography, there has been little formal work addressing the design and analysis of general multi-purpose KDFs. In practice, most KDFs (including those widely standardized) follow ad-hoc approaches that treat cryptographic hash functions as perfectly random functions. In this paper we close some gaps between theory and practice by contributing to the study and engineering of KDFs in several ways. We provide detailed rationale for the design of KDFs based on the extract-then-expand approach; we present the first general and rigorous definition of KDFs and their security that we base on the notion of computational extractors; we specify a concrete fully practical KDF based on the HMAC construction; and we provide an analysis of this construction based on the extraction and pseudorandom properties of HMAC. The resultant KDF design can support a large variety of KDF applications under suitable assumptions on the underlying hash function; particular attention and effort is devoted to minimizing these assumptions as much as possible for each usage scenario. Beyond the theoretical interest in modeling KDFs, this work is intended to address two important and timely needs of cryptographic applications: (i) providing a single hash-based KDF design that can be standardized for use in multiple and diverse applications, and (ii) providing a conservative, yet efficient, design that exercises much care in the way it utilizes a cryptographic hash function. (The HMAC-based scheme presented here, named HKDF, is being standardized by the IETF.)
Ex-vessel Pricing and IFQs: A Strategic Approach

Abstract In this article, intraseasonal fishing is modeled as a differential game between fishers in a total allowable catch (TAC)–regulated fishery with and without individual fishing quotas (IFQs). Heterogeneous harvest values are included by incorporating time-specific harvest costs and a cumulative-harvest effect into fishers' profit functions. I also allow for strategic interaction among fishers via ex-vessel price dynamics. The equilibrium harvest strategies of the differential games are solved numerically through the use of a genetic algorithm. It is demonstrated how different harvesting sector environments lead to varying degrees of ex-vessel price increases when IFQs are implemented. The primary result shows that possible margins for competition among fishers, other than competition for a greater share of the TAC, can exist even under IFQ management and this competition, especially when combined with noncompetitive processors, may be substantial enough to prevent sizeable rent transfers from the ...
A vector constant modulus algorithm for shaped constellation equalization

The constant modulus algorithm (CMA), a popular method for performing blind equalization, has the drawback of failing when the input data has a Gaussian distribution or a kurtosis larger than three. This means that source shaping (which is used to increase the shaping gain) can produce data unequalizable by CMA and other important blind equalization techniques. This paper proposes a simple extension of CMA that blindly equalizes many types of shaped constellations, including those shaped by shell mapping.
Life in the Pits: Competitive Market Making and Inventory Control

We use futures transaction data to investigate cross-sectional relationships between market-maker inventory positions and trade activity. The investigation documents strongly that traders control inventory throughout the trading day. Despite this evidence of inventory management, typical inventory control models are contradicted by our data. These inventory models predict that market-maker reservation prices are negatively influenced by inventory. Surprisingly, our evidence shows, as a strong and consistent empirical regularity, that correlations between inventory and reservation prices are positive. We interpret the evidence as consistent with active position taking by futures market floor traders. Article published by Oxford University Press on behalf of the Society for Financial Studies in its journal, The Review of Financial Studies.
A variance reduction framework for stable feature selection

Stability of feature selection is an important but under-addressed issue in knowledge discovery from high-dimensional data. In this study, we present a theoretical framework about the relationship between the stability and the accuracy of feature selection based on a formal bias-variance decomposition of feature selection error. The framework also reveals the connection between stability and sample size and suggests a variance reduction approach for improving the stability of feature selection algorithms under small sample size. Following the theoretical framework, we propose an empirical variance reduction framework, margin-based instance weighting, which weights training instances according to their importance to feature evaluation. Our extensive experimental study first verifies the theoretical and empirical frameworks based on synthetic data sets and a popular feature selection algorithm SVM-RFE. Experiments based on real-world microarray data sets further verify that the empirical framework is effective at reducing the variance and improving the subset stability of two representative feature selection algorithms, SVM-RFE and ReliefF, while maintaining comparable predictive accuracy based on the selected features. The proposed instance weighting framework is also shown to be more effective and efficient than the ensemble framework at improving the subset stability of the feature selection algorithms under study. © 2012 Wiley Periodicals, Inc. Statistical Analysis and Data Mining, 2012 © 2012 Wiley Periodicals, Inc.
Using mixtures of biological samples as process controls for RNA-sequencing experiments.

Genome-scale “-omics” measurements are challenging to benchmark due to the enormous variety of unique biological molecules involved. Mixtures of previously-characterized samples can be used to benchmark repeatability and reproducibility using component proportions as truth for the measurement. We describe and evaluate experiments characterizing the performance of RNA-sequencing (RNA-Seq) measurements, and discuss cases where mixtures can serve as effective process controls. We apply a linear model to total RNA mixture samples in RNA-seq experiments. This model provides a context for performance benchmarking. The parameters of the model fit to experimental results can be evaluated to assess bias and variability of the measurement of a mixture. A linear model describes the behavior of mixture expression measures and provides a context for performance benchmarking. Residuals from fitting the model to experimental data can be used as a metric for evaluating the effect that an individual step in an experimental process has on the linear response function and precision of the underlying measurement while identifying signals affected by interference from other sources. Effective benchmarking requires well-defined mixtures, which for RNA-Seq requires knowledge of the post-enrichment ‘target RNA’ content of the individual total RNA components. We demonstrate and evaluate an experimental method suitable for use in genome-scale process control and lay out a method utilizing spike-in controls to determine enriched RNA content of total RNA in samples. Genome-scale process controls can be derived from mixtures. These controls relate prior knowledge of individual components to a complex mixture, allowing assessment of measurement performance. The target RNA fraction accounts for differential selection of RNA out of variable total RNA samples. Spike-in controls can be utilized to measure this relationship between target RNA content and input total RNA. Our mixture analysis method also enables estimation of the proportions of an unknown mixture, even when component-specific markers are not previously known, whenever pure components are measured alongside the mixture.
Effects of Acoustic Disturbances on Measured Flow Characteristics Through a Contraction

An experiment involving the addition of randomly phased broadband acoustic disturbance to the flow through an axisymmetric contraction was conducted. Measurements of flow characteristics such as turbulence intensities, velocity spectra, and coherence functions were made at various locations through the contraction using two flow conditions. Acoustic excitation was shown to substantially increase the measured streamwise component of turbulence while leaving the radial component virtually unchanged. Although the radial component of turbulence energy remains relatively unaffected (less than 3%) inside the contracting region, a sudden increase was observed at the downstream end of the contraction. The coherence at x/L = 0.75 for the acoustically excited flow contains a small band of frequencies with low coherence. The location of the low-coherence frequency band was sensitive to the incoming flow condition, suggesting some type of turbulence/ac oustic interaction. Nomenclature : area c = contraction area ratio / = frequency, Hz or kHz L = contraction length M = turbulence-generating grid mesh size r = radial coordinate, measured from centerline R, R(x) = radius of contraction contour at x s = lateral distance from the axis of symmetry SPL = sound pressure level (dB Re 2 X 10"5 N/m2) u' = root-mean-square of velocity fluctuations in the streamwise direction U, U(x) = streamwise mean velocity v' = root-mean-square of velocity fluctuations in the radial direction V = radial (or lateral) component of mean velocity x = direction parallel to test section and contraction's axis of symmetry
Thermodynamic modeling of the Ba–Ni–Ti system

Abstract The binary Ba–Ni and Ba–Ti systems are modeled by computational thermodynamics using the CALculation of PHAse Diagram (CALPHAD) method, wherein the thermodynamic parameters of disordered bcc, fcc and hcp phases are evaluated in terms of the first-principles calculations using the special quasirandom structures (SQSs). In combination with the Ni–Ti system modeling in the literature, the phase equilibria of the Ba–Ni–Ti system are predicted. Isothermal section of the ternary system is presented.
NIOSH-Sponsored Research in Through-the-Earth Communications for Mines: A Status Report

This paper presents the results of recent contractual research sponsored by the National Institute for Occupational Safety and Health that aimed at demonstrating the feasibility of through-the-earth (TTE) wireless communication in mining. TTE systems, developed by five different contractors, are discussed with a focus on technical approach, prototype hardware, and field test results. System features include both magnetic and electric field sensing, loop and line antennas, digital and analog processing, noise filtering and cancelation, and direction finding. The systems were demonstrated at commercial mine sites. The results of these tests are characterized by transmission range and power levels. This paper concludes with a discussion of issues that remain to be resolved as TTE communications are implemented. These include text versus voice format, acceptable time delays, portability, ease of deployment, an interface with existing communications systems, permissibility, and the effect of geological variations.
Largamides A-H, unusual cyclic peptides from the marine cyanobacterium Oscillatoria sp.

Seven new depsipeptides, termed largamides A−G (1−7), and one new cyclic peptide, largamide H (8), have been isolated from the marine cyanobacterium Oscillatoria sp. Their structures were determined by NMR and ESI-MS techniques. The absolute configurations were assigned using LC-MS, chiral HPLC, and combined analysis of homonuclear and heteronuclear 2,3J couplings, along with ROE data. Largamides, isolated from a single homogeneous cyanobacterial collection, represent three different structural classes of peptides. Largamides A−C (1−3) are characterized by the unusual occurrence of a senecioic acid unit, while largamides B (2) and C (3) possess in addition the rare 2-amino-5-(4‘-hydroxyphenyl)pentanoic acid (Ahppa) and the novel 2-amino-6-(4‘-hydroxyphenyl)hexanoic acid (Ahpha), respectively. Largamides D−G (4−7) are the first 3-amino-6-hydroxy-2-piperidone acid (Ahp)-containing depsipeptides reported with the rare Ahppa unit. Largamide H (8) is a unique cyclic peptide displaying a new 2,5-dihydroxylated ...
Identity and spirituality: A psychosocial exploration of the sense of spiritual self.

The authors examined the structure and content of adults' sense of spiritual identity by analyzing semistructured interviews with 13 spiritually devout men and 15 devout women, ages 22 to 72. Individuals' responses to the Role-Related Identity Interview (G. T. Sorell, M. J. Montgomery, & N. A. Busch-Rossnagel, 1997b) were content analyzed and rated on the role-related spiritual identity dimensions of role salience and flexibility. Individuals were categorized as spiritually foreclosed, achieved, or in moratorium, on the basis of their motivational, affective, self-evaluative, and behavioral investments in spiritually defined roles and their reflectiveness about and behavioral changes in role-related spiritual identity. Similarities and differences within and between spiritual identity status groups were observed, suggesting a variety of ways that spiritual identity provides a sense of continuity as well as a domain for adult developmental change.
Exploration of the bicyclo[3.3.1]nonane system as a template for the development of new ligands for the estrogen receptor.

Three novel structural motifs based on a bicyclo [3.3.1]nonane template were examined as new ligands for estrogen receptor (ER). Type III compounds emerged as the most promising leads for developing high-affinity ER ligands, but they showed little selectivity for either ER subtype. Type II compounds, on the other hand, despite their lower affinity, exhibited significant ERβ binding selectivity.
Chiral synthesis of maconelliol: a novel cyclobutanoid terpene alcohol from pink hibiscus mealybug, Maconellicoccus hirsutus

The chiral synthesis of maconelliol, [2,2-dimethyl-3-(1-methylethylidene)cyclobutyl] methanol, the alcohol moiety of the major sex pheromone component isolated from the pink hibiscus mealybug, Maconellicoccus hirsutus, is described. The compound was synthesized in six steps from alpha-pinene and the key step is dehydration of 5 to 7 through the intermediate 6. The absolute configuration of the naturally occurring maconelliol was determined as R.
On the gains from monetary policy commitment under deep habits

Abstract I study the welfare gains from commitment relative to discretion in the context of an equilibrium model that features deep habits in consumption. Policy simulations reveal that the welfare gains are increasing in the degree of habit formation and economically significant for a range of values consistent with U.S. data. I trace these results to the supply-side effects that deep habits impart on the economy and show that they ultimately weaken the stabilization trade-offs facing a discretionary planner. Most of the inefficiencies from discretion, it turns out, can be avoided by installing commitment regimes that last just two years or less. Extending the commitment horizon further delivers marginal welfare gains that are trivial by comparison.
Analysis and design of CMOS Manchester adders with variable carry-skip

Two different CMOS implementations of the Manchester carry-skip adder are analyzed using the RC timing model, which provides a unified way of analyzing both CMOS circuits and interconnect. Based on the RC timing model, the authors develop efficient polynomial algorithms to determine near-optimal (in latency) as well as optimal block sizes for the one-level manchester adder with variable carry-skip. An analysis shows that the carry-skip delay in a Manchester adder block is linearly proportional to the block size. The approach provides a general paradigm for analysis and design, applicable to different models of ripple-propagation and carry skip. >
Trading Networks and Equilibrium Intermediation

We consider a network of intermediaries facilitating exchange between buyers and a seller. Intermediary traders face a private trading cost, a network characterizes the set of feasible transactions, and an auction mechanism sets prices. We examine stable and equilibrium networks. Stable networks, which are robust to agents’ collusive actions, exist when cost uncertainty is acute and multiple, independent trading relationships are valuable. A free-entry process governs the formation of equilibrium networks. Such networks feature too few intermediaries relative to the optimal market organization and they exhibit an asymmetric structure amplifying the shocks experienced by key intermediaries. Welfare and empirical implications of stable and equilibrium networks are investigated.
Electrophilic amination of aromatics with sodium azide in BF3–H2O

Abstract Boron trifluoride monohydrate is an excellent Bronsted acid catalyst system for a wide range of reactions. It is a non-oxidizing acid catalyst prepared easily by bubbling BF 3 into water. We have found boron trifluoride monohydrate/sodium azide combination to be an efficient reagent system for aromatic electrophilic amination. The present method avoids the use of expensive superacids such as trifluoromethanesulfonic acid and provides a facile access to aromatic amines directly from aromatics.
Narrative Variations in a Virtual Storyteller

Research on storytelling over the last 100 years has distinguished at least two levels of narrative representation (1) story, or fabula; and (2) discourse, or sujhet. We use this distinction to create Fabula Tales, a computational framework for a virtual storyteller that can tell the same story in different ways through the implementation of general narratological variations, such as varying direct vs. indirect speech, character voice (style), point of view, and focalization. A strength of our computational framework is that it is based on very general methods for re-using existing story content, either from fables or from personal narratives collected from blogs. We first explain how a simple annotation tool allows naive annotators to easily create a deep representation of fabula called a story intention graph, and show how we use this representation to generate story tellings automatically. Then we present results of two studies testing our narratological parameters, and showing that different tellings affect the reader’s perception of the story and characters.
New partially hyperbolic dynamical systems I

We propose a new method for constructing partially hyperbolic diffeomorphisms on closed manifolds. As a demonstration of the method we show that there are simply connected closed manifolds that support partially hyperbolic diffeomorphisms. Laying aside many surgery constructions of 3-dimensional Anosov flows, these are the first new examples of manifolds which admit partially hyperbolic diffeomorphisms in the past forty years.
Avoiding interruptions - QoE trade-offs in block-coded streaming media applications

We take an analytical approach to study Quality of user Experience (QoE) for media streaming applications. We use the fact that random linear network coding applied to blocks of video frames can significantly simplify the packet requests at the network layer and avoid duplicate packet reception. We model the receiver's buffer as a queue with Poisson arrivals and deterministic departures. We consider the probability of interruption in video playback (buffer underflow) as well as the number of initially buffered packets (initial waiting time) as the QoE metrics. We explicitly characterize the optimal trade-off between these metrics by providing upper and lower bounds on the minimum initial buffering required to achieve certain level of interruption probability for different regimes of the system parameters. Our bounds are asymptotically tight as the file size goes to infinity. Further, we show that for arrival rates slightly larger than the play rate, the minimum initial buffering remains bounded as the file size grows. This is not the case when the arrival rate and the play rate match.