cssi/SciSciGPT-SciSciNet huggingface dataset:
Niche firms, mass markets, and income across countries: Accounting for the impact of entry costs

Abstract I develop a model of monopolistic competition in which I distinguish between niche markets and mass markets, in the spirit of Holmes and Stevens, 2014 . Firms choose between entering a small niche market with high markups or a large mass market with low markups. Entry costs and other distortions have a much greater impact on output in the niche market as the gains to specialization are high, relative to the mass market where varieties are highly substitutable. Calibrated to match data from U.S. manufacturing, the model generates an elasticity of total factor productivity with respect to entry costs almost twice that in a model that abstracts from heterogeneous markets. I use data on entry costs across countries to show entry costs alone can account for 23 percent of the cross-country variation in income per worker.
Urinary tract infections.

Recent advances have led to a renewed interest in urinary tract infections in females. First, current research has reassessed the previously used definition of infection as a positive culture with ≥ 100,000 colonies per ml. Norden and Kass1 originally defined a positive culture as ≥ 105 colonies per ml because they found a 96% predictability of a third positive culture if the 2 previous cultures were positive. However, their studies primarily involved pregnant women who were asymptomatic at the time of culture and were not known to be at high risk for recurrent disease. Other authors2,3 reported that symptomatic disease is often associated with colony counts of less than 105 colonies per ml. These studies have thus led to reconsideration of the best way to define infection microbiologically. The roles of new pathogens such as Chlamydia trachomatis, herpes simplex virus (HSV), and Staphylococcus saprophytics have also been demonstrated in recent studies.
Pressure Dependence of the Electrical Properties of Gabi Solidified in Low Gravity

Immiscible GaBi alloys were solidified during free fall in the Marshall Space Flight Cente4 drop tower which provides about 4.5 seconds of low gravity (about 10 −4 g, g = 980 cm/s 2 ). We have measured the electrical resistivity and magnetic susceptibility as a function of pressure (up to 18 kbar) and temperature (300K to 4.2K) of drop tower (DT) sample and ground control (GC) sample prepared under identical conditions except for gravity. At ambient pressure the electrical resistance of the DT sample exhibits a broad maximum at 100K, while that of GC sample decreases rapidly as temperature decreases. Both DT and GC samples becomesuperconducting at 7.7K (T c2 ). However, a minor second superconducting phase with a transition temperature at 8.3K (T c1 ) is observed only in the DT samples.
A theory of change in turbulent environments: the sequencing of dynamic capabilities following industry deregulation

The dynamics of change and the path-dependent evolution of resources and capabilities are central concerns of contemporary strategic management. This paper integrates the resource-based and dynamic capabilities literatures to explain why development of dynamic capabilities is especially important for firms that transition from regulated to deregulated environments. We develop a theoretical model and specific propositions concerning the pattern and sequencing of dynamic capability development within environments experiencing substantial change, specifically in newly deregulated industries. We discuss implications of the proposed theoretical model for both research and managerial practice.
Use of haplotypes to estimate Mendelian sampling effects and selection limits

Limits to selection and Mendelian sampling (MS) terms can be calculated using haplotypes by summing the individual additive effects on each chromosome. Haplotypes were imputed for 43 382 single-nucleotide polymorphisms (SNP) in 1455 Brown Swiss, 40 351 Holstein and 4064 Jersey bulls and cows using the Fortran program findhap.f90, which combines population and pedigree haplotyping methods. Lower and upper bounds of MS variance were calculated for daughter pregnancy rate (a measure of fertility), milk yield, lifetime net merit (a measure of profitability) and protein yield assuming either no or complete linkage among SNP on the same chromosome. Calculated selection limits were greater than the largest direct genomic values observed in all breeds studied. The best chromosomal genotypes generally consisted of two copies of the same haplotype even after adjustment for inbreeding. Selection of animals rather than chromosomes may result in slower progress, but limits may be the same because most chromosomes will become homozygous with either strategy. Selection on functions of MS could be used to change variances in later generations.
The essential synthesis of problem frames and assurance cases

: Problem frames and assurance cases are two current research areas that can improve – and have improved – system dependability, in critical and noncritical systems alike. While these two techniques are effective separately, their synthesis is much more powerful. This paper describes the synthesis of these two techniques and the rationale behind the synthesis, the particular pieces that influence each other, and the beginning of a process to integrate the two in software system development. A detailed example of the application of the synthesis is also provided.
Gamma-ray bursts and cosmology

I review the current status of the use of gamma-ray bursts (GRBs) as probes of the early Universe and cosmology. I describe the promise of long GRBs as probes of the high redshift (z>4) and very high redshift (z>5) Universe, and several key scientific results that have come from observations made possible by accurate, rapid localizations of these bursts by Swift. I then estimate the fraction of long GRBs that lie at very high redshifts and discuss ways in which it may be possible to rapidly identify-and therefore study-a larger number of these bursts. Finally, I discuss the ways in which both long and short GRBs can be made 'standard candles' and used to constrain the properties of dark energy.
Wellness as a Worldwide Phenomenon

This article examines the concept of wellness through a comparative political economy and legal framework. It asks whether wellness, an increasingly defined term within US federal and state legislative instruments including, for example, the Patient Protection and Affordable Care Act, is primarily a US-centric phenomenon. Or is wellness, in its various different guises, a worldwide phenomenon? By focusing on three distinctly different jurisdictions - the United States, Germany, and Australia - this article examines wellness through the lens of employers, the health care system, employment and tort law, and the greater political economy. It notes that while improving employee health, well-being, and productivity is common across the three countries and their respective cultures, the focus on wellness as a distinct legal concept is unique to the United States.
Hall effect at the magnetic-field-tuned superconductor-insulator transition

Abstract The Hall effect for disordered superconducting films in magnetic field is discussed, with special focus on the vicinity of the magnetic field-tuned superconductor-insulator transition. Evidence is presented that upon ensemble averaging this transition possesses a “hidden” particle/hole symmetry. This symmetry implies that right at the transition the Hall resistance vanishes. Relevance to recent experiments is discussed briefly.
Flutter of pairs of aerodynamically interfering delta wings.

To examine the effect on flutter of the aerodynamic interference between pairs of closely spaced delta wings, several structurally uncoupled 1/80th-scale models were studied by experiment and analysis. Flutter test boundaries obtained in NASA Langley's 26-in. transonic blowdown wind tunnel were compared with subsonic analytical results generated using the doublet lattice method. Trends for several combinations of vertical and longitudinal wing separation were determined, showing flutter speed significantly affected in the closely spaced configurations. A new flutter mechanism coupling one wing's first bending mode with the other wing's first torsion mode was predicted and observed.
Issues in the design of object-oriented database programming languages

We see a trend toward extending object-oriented languages in the direction of databases, and, at the same time, toward extending database systems with object-oriented ideas. On the surface, these two activities seem to be moving in a consistent direction. However, at a deeper level, we see difficulties that may inhibit their ending up at the same point. We feel that many of these difficulties are a result of the underlying assumptions that are inherent in the fields of programming language and database systems research. Many of these assumptions are historical and contribute to a set of cultural biases that often prevent the two communities from interacting as effectively as possible.The purpose of this paper is to try to uncover some of the cultural presuppositions that have inhibited development of a fully integrated database programming language. We have identified database and language features that seem to be difficult to reconcile. We try to uncover the basic problems in these two areas that these features were intended to solve. In order to resolve these problems, we attempt to distinguish fundamental differences from historical artifacts.
Cohort-level sex ratio effects on women's labor force participation

It follows from a number of theoretical models of marriage that the scarcer women are relative to men, i.e., the higher the sex ratio, the less married women are likely to participate in the labor force. Such sex ratio effects may be stronger among less educated women. These predictions are tested using individual data from Current Population Surveys for four regions of the U.S. (Northeast, Midwest, South and West), and for the U.S. as a whole, covering the period 1965–2005 at 5-year intervals. Within-region sex ratio variation results from variation in cohort size (due principally to large fluctuations in number of births) and limited fluctuations in the difference between male and female age at marriage. As hypothesized, we find that sex ratios are inversely related to women’s labor force participation, reflecting that ceteris paribus women born in years of peak baby-boom are more likely to be in the labor force than women born in years of peak baby-bust. Additionally, weaker sex ratio effects are found among educated women in two of the four regions of the United States.
Biological effects of negative pions

Abstract Most pion radiobiological work in the past was done at low dose rates using biological systems sensitive to small doses. Biological effects at the beam entrance were found to be nearly the same as conventional radiations, although some reports have indicated a higher RBE. LET distribution at the peak of a nearly monoenergetic pion beam is not much different from fast neutrons; therefore, one would expect similar biological responses, and the results are consistent with this hypothesis. The RBE at the peak for a nearly monoenergetic pion beam is significantly higher than at the entrance. The RBE peak/RBE plateau ratio is decreased with increasing width of the peak. The OER (∼1.6) at the peak for a nearly monoenergetic pion beam is also similar to fast neutrons and is expected to increase with increasing width of the peak. No OER data for broad peaks relevant to therapy are available. Preliminary measurements on radiosensitivity variation as a function of cell cycle indicate that there is a slight reduction in variation at the plateau, compared to X-rays, and a significant reduction at the narrow peak. With the availability of increasing intensity of pion beams, more radiobiological work relevant to radiotherapy is in progress at Los Alamos, Vancouver and Zurich.
W Mass results from Tevatron and LHC

Most recent results of W boson mass measurements from Tevatron experiments (CDF and DO) in p ¯ p collisions at p s = 1.96 GeV are reported, using 0.2 f b 1 and 1.0 f b 1 data collected at CDF and DO, respec- tively. The measurements of W boson properties at LHC experiments (ATLAS, CMS, and LHCb) inpp collisions at p s = 7 TeV, using data collected before Summer 2011, are presented. These measurements are essential at the preparation stage of the W boson mass measurements at LHC. Challenges for W mass measurement at the LHC in comparison with the Tevatron are outlined. Prospects for W mass precision with upcoming measurements and its implications are discussed.
Pay Equity or Pay Fairness

Does attention to pay satisfaction-employee perceived pay fairness— have dysfunctional consequences for organizations? The oldest and most persistent pay question—What is fair pay?-is reconsidered.
Practical repeater insertion for low power: what repeater library do we need?

This paper investigates the problem of repeater insertion for low power under a given timing budget. A novel repeater insertion algorithm is proposed to compute the optimal repeater number and width in the discrete solution space, as defined by a given repeater library. Using the proposed algorithm, two practical and highly important questions are addressed. Given a certain tolerance to the degradation of repeater power dissipation: 1) how coarse could the repeater size granularity be? 2) What range should repeater widths be in? The experimental results provide valuable insights into repeater library design. Specifically, the investigation reveals that coarse repeater size granularities can be used to reduce the library size by more than 87% with merely a 4% power degradation. Moreover, for two-pin interconnects with various wire lengths and timing targets, the range of optimal repeater sizes for low power is limited, indicating that a low-cost small-size repeater library, if well designed, is adequate to provide high-quality repeater insertion solutions. The proposed scheme can be used in early design stages to generate a compact repeater library that is passed on to other repeater insertion algorithms.
Photometric Redshifts and Morphologies of Galaxies in the NICMOS Parallel Fields

We present positions, magnitudes, sizes, and morphological classi—cations for 111 galaxies discovered in the Hubble Space Telescope NICMOS camera 1 and camera 2 parallel —elds. We combine the magni- tudes measured in the JHK-analog —lters with those from deep ground-based images in V and/or R to measure photometric redshifts for 71 objects using Bruzual & Charlot population synthesis models. We —nd that these objects fall in the range z D 0.0¨2.7, with SzT + 0.8 and a mean luminosity SL T + 1.6L*. The NICMOS images reveal many of the galaxies to be ordered spirals and ellipticals similar to those in the local universe, with a high degree of symmetry and brightness pro—les that are well —tted by de Vaucouleurss r1@4 and exponential disk laws. However, we —nd a higher fraction (D14%) of morphologi- cally peculiar and/or interacting galaxies in the sample than is observed among local galaxies (D3%¨ 4%). This is consistent with the result from other deep HST images including the Hubble Deep Field and Hubble Medium Deep Survey —eld that the fraction of peculiar and interacting galaxies increases with redshift. As the NICMOS images of the sample galaxies cover their rest-frame near-infrared and optical emission, this result increases con—dence that such changes in morphology are genuine, as opposed to an eUect produced by viewing galaxies in the rest-frame ultraviolet. We also —nd that at least 26 of the sample galaxies appear to be members of (noninteracting) pairs or groups, based on their pro- mixity to one another and photometric redshifts. This is consistent with the results of recent ground- based optical surveys for faint galaxies covering larger areas and with the detection of galaxy groups and —laments at redshifts higher than those covered by the present sample.
Who shot FAP? The Nixon welfare plan and the transformation of American politics

This essay takes the battle over President Nixon’s proposals for welfare reform as a lens through which to understand political change at the end of the 1960s. In explaining the rise and fall of the Family Assistance Plan, it argues that scholars should take their attention away from President Nixon and place it on the times during which he governed, especially on grassroots protest, the response to it, and the complexities of the Republican coalition. It adds to the research on the 1960s an appreciation of the changing role of liberal Republicans. It adds to the study of domestic policy an understanding of how the Vietnam war shaped policy at home. It adds to political history an account of welfare politics amidst the conservative renaissance of the early 1970s.
Interelectrode resistance and performance of small- and large-scale MHD generators

The effect of reduced interelectrode resistance in MHD generators on the generator power output is investigated. The analytical model used in the investigation allows for the solution for the electric field and current density distributions in the cross plane of the generator. The power output, expressed as a fraction of the power output of a perfectly insulated generator, is found to be a function of the wall temperature, the ratio of boundary layer thickness to channel transverse dimension, and the product of interelectrode resistance and channel cross-sectional area. The interelectrode resistance is assumed to be inversely proportional to the channel transverse dimension and the variation of power output ratio with channel size is calculated. It is found that deterioration of performance of NHD generators, resulting from reduced interelectrode resistance, diminishes with generator size and is negligible for large-scale generators, provided that the interelectrode resistance remains larger than an order of one-tenth ohm.
Dynamic networks reveal key players in aging

MOTIVATION Because susceptibility to diseases increases with age, studying aging gains importance. Analyses of gene expression or sequence data, which have been indispensable for investigating aging, have been limited to studying genes and their protein products in isolation, ignoring their connectivities. However, proteins function by interacting with other proteins, and this is exactly what biological networks (BNs) model. Thus, analyzing the proteins' BN topologies could contribute to the understanding of aging. Current methods for analyzing systems-level BNs deal with their static representations, even though cells are dynamic. For this reason, and because different data types can give complementary biological insights, we integrate current static BNs with aging-related gene expression data to construct dynamic age-specific BNs. Then, we apply sensitive measures of topology to the dynamic BNs to study cellular changes with age. RESULTS While global BN topologies do not significantly change with age, local topologies of a number of genes do. We predict such genes to be aging-related. We demonstrate credibility of our predictions by (i) observing significant overlap between our predicted aging-related genes and 'ground truth' aging-related genes; (ii) observing significant overlap between functions and diseases that are enriched in our aging-related predictions and those that are enriched in 'ground truth' aging-related data; (iii) providing evidence that diseases which are enriched in our aging-related predictions are linked to human aging; and (iv) validating our high-scoring novel predictions in the literature. AVAILABILITY AND IMPLEMENTATION Software executables are available upon request.
Active planning for underwater inspection and the benefit of adaptivity

We discuss the problem of inspecting an underwater structure, such as a submerged ship hull, with an autonomous underwater vehicle (AUV). Unlike a large body of prior work, we focus on planning the views of the AUV to improve the quality of the inspection, rather than maximizing the accuracy of a given data stream. We formulate the inspection planning problem as an extension to Bayesian active learning, and we show connections to recent theoretical guarantees in this area. We rigorously analyze the benefit of adaptive re-planning for such problems, and we prove that the potential benefit of adaptivity can be reduced from an exponential to a constant factor by changing the problem from cost minimization with a constraint on information gain to variance reduction with a constraint on cost. Such analysis allows the use of robust, non-adaptive planning algorithms that perform competitively with adaptive algorithms. Based on our analysis, we propose a method for constructing 3D meshes from sonar-derived point clouds, and we introduce uncertainty modeling through non-parametric Bayesian regression. Finally, we demonstrate the benefit of active inspection planning using sonar data from ship hull inspections with the Bluefin-MIT Hovering AUV.
Return-limited inductances: a practical approach to on-chip inductance extraction

Decreasing slew rates and efforts to reduce the resistance-capacitance (RC) delays of on-chip interconnect through design and technology have resulted in the growing importance of inductance in analyzing interconnect response for timing and noise analysis. In this paper, we consider a practical approach for extracting approximate inductances of on-chip interconnect. This approach, which we call the method of return-limited inductances, is based on performing the inductance modeling of signal lines and power-ground lines independently and on taking advantage of the power and ground distribution of the chip to localize inductive coupling. A set of simple geometry-based matrix decomposition rules guide sparsification in these extractions.
Separation Cutoffs for Random Walk on Irreducible Representations

Random walk on the irreducible representations of the symmetric and general linear groups is studied. A separation distance cutoff is proved and the exact separation distance asymptotics are determined. A key tool is a method for writing the multiplicities in the Kronecker tensor powers of a fixed representation as a sum of non-negative terms. Connections are made with the Lagrange-Sylvester interpolation approach to Markov chains.
Optimization of the hyperspectral imaging-based spatially-resolved system for measuring the optical properties of biological materials

This paper reports on the optimization and assessment of a hyperspectral imaging-based spatially-resolved system for determination of the optical properties of biological materials over the wavelengths of 500-1,000 nm. Twelve model samples covering a wide range of absorption and reduced scattering coefficients were created to validate the hyperspectral imaging system, and their true values of absorption and reduced scattering coefficients were determined and then cross-validated using three commonly used methods (i.e., transmittance, integrating sphere, and empirical equation). Light beam and source-detector distance were optimized through Monte Carlo simulations and experiments for the model samples. The optimal light beam should be of Gaussian type with the diameter of less than 1 mm, and the optimal minimum and maximum source-detector distance should be 1.5 mm and 10-20 mean free paths, respectively. The optimized hyperspectral imaging-based spatially-resolved system achieved good estimation of the optical parameters.
Finite State Channels With Time-Invariant Deterministic Feedback

We consider capacity of discrete-time channels with feedback for the general case where the feedback is a time-invariant deterministic function of the output samples. Under the assumption that the channel states take values in a finite alphabet, we find a sequence of achievable rates and a sequence of upper bounds on the capacity. The achievable rates and the upper bounds are computable for any N, and the limits of the sequences exist. We show that when the probability of the initial state is positive for all the channel states, then the capacity is the limit of the achievable-rate sequence. We further show that when the channel is stationary, indecomposable, and has no intersymbol interference (ISI), its capacity is given by the limit of the maximum of the (normalized) directed information between the input XN and the output YN, i.e., C=limNrarrinfin(1/n)max I(XNrarrYN) where the maximization is taken over the causal conditioning probability Q(xNparzN-1) defined in this paper. The main idea for obtaining the results is to add causality into Gallager's results on finite state channels. The capacity results are used to show that the source-channel separation theorem holds for time-invariant determinist feedback, and if the state of the channel is known both at the encoder and the decoder, then feedback does not increase capacity.
Economic Freedom and Economic Growth: A Short-Run Causal Investigation

The freedom and growth literature has consistently shown that nations which have fewer restrictions on private agents and transactions tend to higher levels of economic growth. It is less clear, however, whether freedom causes growth, growth causes freedom, or the two are jointly determined. To assess these possibilities, Granger-causality tests are performed on annual freedom indicators developed by the Heritage Foundation and national growth rates. The underlying component indexes, which include Trade Policy, Taxation, Government Intervention, Monetary Policy, Capital Flows and Foreign Investment, Banking, Wage and Price Controls, Property Rights, Regulation, and Black Markets, are also tested in addition to the summary freedom rating. The tests suggest the average level of freedom in a nation, as well as many of the specific underlying components of freedom, precedes growth. However, growth may precede one of the component indexes (Government Intervention), and no relationship is found to exist between growth and two of the indexes (Trade Policy and Taxation).
AN EFFICIENT DYNAMIC MECHANISM

This paper constructs an efficient, budget-balanced, Bayesian incentive-compatible mechanism for a general dynamic environment with quasilinear payoffs in which agents observe private information and decisions are made over countably many periods. First, under the assumption of "private values" (other agents' private information does not directly affect an agent's payoffs), we construct an efficient, ex post incentive-compatible mechanism, which is not budget-balanced. Second, under the assumption of "independent types" (the distribution of each agent's private information is not directly affected by other agents' private information), we show how the budget can be balanced without compromising agents' incentives. Finally, we show that the mechanism can be made self-enforcing when agents are sufficiently patient and the induced stochastic process over types is an ergodic finite Markov chain. [PUBLICATION ABSTRACT]
Mechanism and Scope of the Cyanide-Catalyzed Cross Silyl Benzoin Reaction

In this work, cross silyl benzoin addition reactions between acylsilanes (1) and aldehydes (2) catalyzed by metal cyanides are described. Unsymmetrical aryl-, heteroaryl-, and alkyl-substituted benzoin adducts can be generated in moderate to excellent yields with complete regiocontrol using potassium cyanide and a phase transfer catalyst. From a screen of transition metal cyanide complexes, lanthanum tricyanide was identified as an improved second-generation catalyst for the cross silyl benzoin reaction. A study of the influence of water on the KCN-catalyzed cross silyl benzoin addition revealed more practical reaction conditions using unpurified solvent under ambient conditions. A sequential silyl benzoin addition/cyanation/O-acylation reaction that resulted in two new C−C bonds was achieved in excellent yield. The mechanism of cross silyl benzoin addition is proposed in detail and is supported by crossover studies and a number of unambiguous experiments designed to ascertain the reversibility of key ste...
Immunofluorescence laser micro‐dissection of specific nephron segments in the mouse kidney allows targeted downstream proteomic analysis

Laser micro-dissection (LMD) is a very useful tool that allows the isolation of finite areas from tissue specimens for downstream analysis of RNA and protein. Although LMD has been adapted for use in kidney tissue, the use of this powerful tool has been limited by the diminished ability to identify specific tubular segments in the kidney. In this study, we describe a major improvement in the methodology to isolate specific cells in the mouse kidney using immunofluorescence LMD (IF-LMD). Using IF-LMD, we can reproducibly isolate not only glomeruli, but also S1–S2 proximal segments, S3 tubules, and thick ascending limbs. We also demonstrate the utility of a novel rapid immunofluorescence staining technique, and provide downstream applications for IF-LMD such as real-time PCR and cutting-edge proteomic studies. This technical breakthrough may become an invaluable tool for understanding cellular and molecular events in the heterogeneous kidney milieu.
DC-20 GHz N*M passive switches

High-order, bidirectional, DC-20-GHz switch networks are discussed. Single-chip 1*2, 1*4, and 2*2 switch MMICs have been demonstrated. Multiple chips have been used to demonstrate 4*4 and 1*16 switches. The switches all use a combination of series and shunt passive FET switching elements. The 1*4 switch is made of a single stage of switching elements, rather than the usual two stages of 1*2 switches. The 2*2 switch is comprised of two stages of 1*2 switches. The multiple-chip 4*4 switch is made of four stages of 1*2 switches (using the 2*2 switch MMICs). Two stages of 1*4 switches are used to make the 1*16 switch. >
The Performance of BICM With a Single Decision Feedback for the AWGN Channel

This paper studies the performance of bit interleaved coded modulation (BICM) with a single decision feedback. The separation of demodulation and decoding in BICM inevitably reduces the channel's capacity. Altering the conventional bit mapping in BICM and allowing a single decision feedback greatly reduces the capacity loss. The extra complexity introduced by the single decision feedback appears well justified for dense constellations.
Theory of thermal emission from periodic structures

We provide a momentum space formulation for thermal emission from photonic crystals and corroborate Kirchhoff's law for periodic structures. This formalism allows us to calculate the optical coherence in the far and near fields of photonic crystals. Calculations in the far field show that the exchange of momentum between a linear grating and the surface polaritons can significantly decrease the coherence length for the grating compared to that of a flat surface. Considerations in the near field of photonic crystals show that, unlike observations of flat surfaces, the electric energy density does not necessarily decrease as $1/{z}^{3}$ for a distance $z$ from the surface.
Radiation from waves guided by nonuniform active surfaces

The concept of electronically manipulating the complex wavenumbers of waves launched along guiding surfaces is discussed. The concept is based on being able to synthesize surfaces on which the surface impedance boundary condition Z/sub s/ can take on values anywhere in the complex plane. In particular, the author hypothesizes nonuniform surface impedances having a negative real part over some finite portion of the surface. With such a capability, one of several species of guided waves can be propagated at a time and then converted to another species as the wave propagates from one zone to the next having a different Z/sub s/. A number of cases were numerically studied to specify the impedance profiles. >
A Holistic Approach for Risk Management During Design

In this paper, an approach for the identification, assessment, mitigation and continuous management of risks during the process of designing a space mission is presented. This approach has been developed by observing the risk patterns that occur at the Project Design Center of the Jet Propulsion Laboratory (TeamX) which develops conceptual, concurrent design of Space Missions. TeamX develops an end-to-end conceptual design of a Space Mission in a matter of one or two weeks. As the creator and operator of the risk chair in TeamX, the author has had the opportunity to observe the risk patterns that occur during design over the course of many design sessions. This paper introduces an abstraction and generalization of those patterns. Risk is defined as anything that can go wrong, along with its approximate likelihood and consequence. The indicators, and causes, and effects of these risks are cross cutting across the multiple levels of people and processes involved in the design, and the actual design product itself.
Child Health and Economic Crisis in Peru

The effect of macroeconomic crises on child health is a topic of great policy importance. This article analyzes the impact of a profound crisis in Peru on infant mortality. It finds an increase of about 2.5 percentage points in the infant mortality rate for children born during the crisis of the late 1980s, which implies that about 17,000 more children died than would have in the absence of the crisis. Accounting for the precise source of the increase in infant mortality is difficult, but it appears that the collapse in public and private expenditures on health played an important role.
Spatial distributions of young stars

We analyze the spatial distribution of young stars in Taurus-Auriga and Upper Sco, as determined from the two-point correlation function (i.e., the mean surface density of neighbors). The corresponding power-law fits allow us to determine the fractal dimensions of each association’s spatial distribution, measure the stellar velocity dispersions, and distinguish between the bound binary population and chance alignments of members. We find that the fractal dimension of Taurus is D ~ 1.05, consistent with its filamentary structure. The fractal dimension of Upper Sco may be even shallower (D ~ 0.7), but this fit is uncertain due to the limited area and possible spatially variable incompleteness. We also find that random stellar motions have erased all primordial structure on scales of ≾0.07° in Taurus and ≾1.7° in Upper Sco; given ages of ~1 and ~5 Myr, the corresponding internal velocity dispersions are ~0.2 and ~1.0 km s^-1, respectively. Finally, we find that binaries can be distinguished from chance alignments at separations of ≾120" (17,000 AU) in Taurus and ≾75" (11,000 AU) in Upper Sco. The binary populations in these associations that we previously studied, spanning separations of 3"–30", is dominated by binary systems. However, the few lowest mass pairs (Mprim ≾ 0.3M⊙) might be chance alignments.
Influence of Plant Material Handling Protocols on Terpenoid Profiles of One-Seed Juniper Saplings

Accurate estimation of one-seed juniper (Juniperus monosperma [Engelm.] Sarg.) intake by herbivores often requires harvesting, transporting, and storing plant material that is later used in pen experiments. Such manipulation could alter terpenoid profiles and modify herbivory levels significantly. We used gas chromatography mass spectrometry (GC/MS) to analyze the terpenoid profile of leaves from 10 short (0.5 m 6 0.05, mean 6 SE) and 10 tall (1.14 m 6 0.06) one-seed juniper saplings subjected to 3 handling protocols: a) placed on dry ice after clipping and stored after 5 hours at � 808C for 3 weeks (Control); b) kept at ambient temperature for the first 24 hours and then frozen at � 808C for 3 weeks; or c) kept at ambient temperature for the first 24 hours, and then stored at 88C for 3 weeks. Juniper saplings contained 51 terpenoids, 3 of which were unknown compounds. Fourteen terpenoids accounted for 95% of the total amount of volatiles. The most abundant compound was a-pinene, which accounted for 65% of total terpenoids present. Handling protocols were not associated with detectable differences in total terpenoid content (Means 6 SE, Control: 21.68 6 1.42 mg � g � 1 dry matter [DM]; Frozen after 24 hours: 19.55 6 1.08 mg � g � 1 DM; Refrigerated after 24 hours: 18.80 6 1.13 mg � g � 1 DM). However, total terpenoid amount and concentration of a few major compounds tended to decrease with increasing storage temperature. Handling protocols induced detectable variations in a small number of minor terpenoids. We observed large among-plant variation in terpenoid profiles that was not fully explained on the basis of sapling size. This study suggests that the length of storage period of one-seed juniper branches should not exceed 3 weeks and that storage refrigeration temperatures should be kept below 88C to prevent significant alterations in terpenoid profiles.
Copper-Catalyzed Coupling of Aryl Iodides with Aliphatic Alcohols

A simple and mild method for the coupling of aryl iodides and aliphatic alcohols that does not require the use of alkoxide bases is described. The reactions can be performed in neat alcohol. For more precious alcohols, the etherification was carried out in toluene as solvent using 2 equiv of alcohol. Additionally, the cross-coupling of an optically active benzylic alcohol with an unactivated aryl halide was demonstrated to proceed with complete retention of configuration.
Synthesis and structure–activity investigation of iodinated arylhydantoins and arylthiohydantoins for development as androgen receptor radioligands

Abstract A series of side-chain derivatives of the arylhydantoin RU 58841 and the arylthiohydantoin RU 59063, wherein the aromatic trifluoromethyl group was replaced with iodine, was synthesized for possible development as radioiodinated androgen receptor (AR) ligands. Derivatives containing the cyanomethyl, methoxyethyl and propenyl side-chains displayed moderately high affinity (Ki = 20–59 nM) towards the rat AR. Side-chains containing bulky lipophilic groups such as, benzyl and phenylpropyl, were poorly tolerated (Ki > 219 nM). Superior AR binding affinities (0.71 nM
Low-cost sensorless control of brushless DC motors with improved speed range

This paper presents a low-cost position sensorless control scheme for brushless dc motors. Rotor position information is extracted by indirectly sensing the back EMF from only one of the three motor-terminal voltages for a three-phase motor. Depending on the terminal voltage sensing locations, either a low-pass filter or a band-pass filter is used for position information retrieval. This leads to a significant reduction in the component count of the sensing circuit. The cost saving is further increased by coupling the sensing circuit with a single-chip microprocessor or digital signal processor for speed control. In addition, a look-up-table-based correction for the nonideal phase delay introduced by the filter is suggested to ensure accurate position detection even at low speed. This extends the operating speed range and improves motor efficiency. Experimental results are included to verify the proposed scheme.
Synthesis of 2-pentafluorosulfanylnaphthalene

A three step synthesis of 2-pentafluorosulfanylnaphthalene is reported. Initial addition of SF5Cl to benzobarralene was followed by elimination to form 2-pentafluorosulfanylbenzobarralene. Heating of this compound with 3,6-bis-(2-pyridyl)-1,2,4,5-tetrazine led to elimination of the ethylene bridge via a sequence of cycloadditions and retro-cycloadditions to form the title compound.
Choosing Subsamples for Sequencing Studies by Minimizing the Average Distance to the Closest Leaf

Imputation of genotypes in a study sample can make use of sequenced or densely genotyped external reference panels consisting of individuals that are not from the study sample. It also can employ internal reference panels, incorporating a subset of individuals from the study sample itself. Internal panels offer an advantage over external panels because they can reduce imputation errors arising from genetic dissimilarity between a population of interest and a second, distinct population from which the external reference panel has been constructed. As the cost of next-generation sequencing decreases, internal reference panel selection is becoming increasingly feasible. However, it is not clear how best to select individuals to include in such panels. We introduce a new method for selecting an internal reference panel—minimizing the average distance to the closest leaf (ADCL)—and compare its performance relative to an earlier algorithm: maximizing phylogenetic diversity (PD). Employing both simulated data and sequences from the 1000 Genomes Project, we show that ADCL provides a significant improvement in imputation accuracy, especially for imputation of sites with low-frequency alleles. This improvement in imputation accuracy is robust to changes in reference panel size, marker density, and length of the imputation target region.
Off-the-Grid Recovery of Piecewise Constant Images from Few Fourier Samples

We introduce a method to recover a continuous domain representation of a piecewise constant two-dimensional image from few low-pass Fourier samples. Assuming the edge set of the image is localized to the zero set of a trigonometric polynomial, we show that the Fourier coefficients of the partial derivatives of the image satisfy a linear annihilation relation. We present necessary and sufficient conditions for unique recovery of the image from finite low-pass Fourier samples using the annihilation relation. We also propose a practical two-stage recovery algorithm that is robust to model-mismatch and noise. In the first stage we estimate a continuous domain representation of the edge set of the image. In the second stage we perform an extrapolation in Fourier domain by a least squares two-dimensional linear prediction, which recovers the exact Fourier coefficients of the underlying image. We demonstrate our algorithm on the superresolution recovery of MRI phantoms and real MRI data from low-pass Fourier sam...
Electric Field Generation in Martian Dust Devils

Terrestrial dust devils are known to generate electric fields from the vertical separation of charged dust particles. The particles present within the dust devils on Mars may also be subject to similar charging processes and so likely contribute to electric field generation there as well. However, to date, no Marsin situ instrumentation has been deployed to measure electric field strength. In order to explore the electric environment of dust devils on Mars, the triboelectric dust charging physics from the MacroscopicTriboelectric Simulation (MTS) code has been coupled to the Mars Regional Atmospheric ModelingSystem (MRAMS). Using this model, we examine how macroscopic electric fields are generated within martian dust disturbances and attempt to quantify the time evolution of the electrodynamical system.Electric fields peak for several minutes within the dust devil simulations. The magnitude of the electric field is a strong function of the size of the particles present, the average charge on the particles and the number of particles lifted. Varying these parameters results in peak electric fields between tens of millivolts per meter and tens of kilovolts per meter.
Analytical error analysis of Clifford gates by the fault-path tracer method

We estimate the success probability of quantum protocols composed of Clifford operations in the presence of Pauli errors. Our method is derived from the fault-point formalism previously used to determine the success rate of low-distance error correction codes. Here we apply it to a wider range of quantum protocols and identify circuit structures that allow for efficient calculation of the exact success probability and even the final distribution of output states. As examples, we apply our method to the Bernstein---Vazirani algorithm and the Steane [[7,1,3]] quantum error correction code and compare the results to Monte Carlo simulations.
An Unstructured Finite-Volume Method for Incompressible Flows with Complex Immersed Boundaries

A numerical method is developed for solving three-dimensional, unsteady, incompressible flows with immersed moving solids of arbitrary geometric complexity. A co-located (nonstaggered) pressure-based finite-volume method is employed to solve the Navier-Stokes equations for the flow region, and the solid region is represented by material points with known position and velocity. The influence of the body on the flow is accounted for by reconstructing implicitly the velocity on the immersed boundary faces b-tween fluid and solid. Canonical test cases and mesh convergence tests are carried out. A validation test for the vibration of microcantilevers shows good agreement between computed and measured damping factor values.
Transient phases during fast crystallization of organic thin films from solution

We report an in situ microbeam grazing incidence X-ray scattering study of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) organic semiconductor thin film deposition by hollow pen writing. Multiple transient phases are observed during the crystallization for substrate temperatures up to ≈93 °C. The layered smectic liquid-crystalline phase of C8-BTBT initially forms and preceedes inter-layer ordering, followed by a transient crystalline phase for temperature >60 °C, and ultimately the stable phase. Based on these results, we demonstrate a method to produce extremely large grain size and high carrier mobility during high-speed processing. For high writing speed (25 mm/s), mobility up to 3.0 cm2/V-s has been observed.
Comparative evaluation of mandibular canal visibility on cross-sectional cone-beam CT images: a retrospective study.

Objectives:The purpose of this study was to determine the visibility of the mandibular canal (MC) in CBCT images and if the visibility of the MC is affected by gender, location and/or age.Methods:CBCT images were evaluated for the visibility of the MC by a board-certified oral and maxillofacial radiologist, a board-certified periodontist and a periodontics resident. Representative slices were examined for the first premolar (PM1), second premolar (PM2), first molar (M1) and second molar (M2) sites by all examiners. The visibility of the MC was registered as either present or absent.Results:360 total CBCT cross-sectional images were examined, with the MC identified in 204 sites (56%). Age had a significant effect on MC visibility, but it differed by location: for PM1, age 47–56 had lower visibility than age 65+ (p = 0.0377). Gender also had a significant effect on canal visibility, where females had lower visibility than males overall (p = 0.0178) and had the most pronounced difference for PM1 (p = 0.0054)...
An examination of firms’ responses to tax forgiveness

This study uses state tax amnesties to examine how firms respond to forgiveness—particularly repeated forgiveness—by a taxing authority. We posit that tax forgiveness programs alter taxpayer perceptions of the probability of detection by enforcers or the probability of future forgiveness programs, either of which could affect future tax aggressiveness. We find that firms headquartered in an amnesty-granting state increase state income tax aggressiveness following the first instance of tax amnesty, relative to control firms in other states. Moreover, we find evidence that tax aggressiveness incrementally increases with each additional repetition of a tax amnesty. Finally, we find that the effect of amnesties on tax aggressiveness is more prominent for small firms, which face less scrutiny and for which the tax aggressiveness measures are less confounded. Our findings suggest that repeated programs of tax forgiveness have increasingly negative implications for corporate tax collections.
Covariant multipole polarization operators and density matrices for any spin

Covariant multipole polarization operators for a particle with finite nonzero mass and arbitrary spin are constructed by considering the usual multipole expansion of polarization matrices as the rest system operators. Then these multipole operators are used to write down the covariant density matrices and finally their properties are briefly discussed.